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What are pQTLs? | The identification of protein quantitative trait loci (pQTLs) may be a powerful complementary method of improving our understanding of disease pathways. | Proteins are central to almost all cellular processes, and dysregulation of
expression and function is associated with a range of disorders. A number of
studies in human have recently shown that genetic factors significantly
contribute gene expression variation. In contrast, very little is known about
the genetic basis of variation in protein abundance in man. Here, we assayed the
abundance levels of proteins in plasma from 96 elderly Europeans using a new
aptamer-based proteomic technology and performed genome-wide local (cis-)
regulatory association analysis to identify protein quantitative trait loci
(pQTL). We detected robust cis-associations for 60 proteins at a false discovery
rate of 5%. The most highly significant single nucleotide polymorphism detected
was rs7021589 (false discovery rate, 2.5 × 10(-12)), mapped within the gene
coding sequence of Tenascin C (TNC). Importantly, we identified evidence of
cis-regulatory variation for 20 previously disease-associated genes encoding
protein, including variants with strong evidence of disease association show
significant association with protein abundance levels. These results demonstrate
that common genetic variants contribute to the differences in protein abundance
levels in human plasma. Identification of pQTLs will significantly enhance our
ability to discover and comprehend the biological and functional consequences of
loci identified from genome-wide association study of complex traits. This is
the first large-scale genetic association study of proteins in plasma measured
using a novel, highly multiplexed slow off-rate modified aptamer (SOMAmer)
proteomic platform. The progression of liver fibrosis in response to chronic injury varies
considerably among individual patients. The underlying genetics is highly
complex due to large numbers of potential genes, environmental factors and cell
types involved. Here, we provide the first toxicogenomic analysis of liver
fibrosis induced by carbon tetrachloride in the murine 'genetic reference panel'
of recombit inbred BXD lines. Our aim was to define the core of risk genes
and gene interaction networks that control fibrosis progression. Liver fibrosis
phenotypes and gene expression profiles were determined in 35 BXD lines.
Quantitative trait locus (QTL) analysis identified seven genomic loci
influencing fibrosis phenotypes (pQTLs) with genome-wide significance on
chromosomes 4, 5, 7, 12, and 17. Stepwise refinement was based on expression QTL
mapping with stringent selection criteria, reducing the number of 1,351
candidate genes located in the pQTLs to a final list of 11 cis-regulated genes.
Our findings demonstrate that the BXD reference population represents a powerful
experimental resource for shortlisting the genes within a regulatory network
that determine the liver's vulnerability to chronic injury. Annotating and interpreting the results of genome-wide association studies
(GWAS) remains challenging. Assigning function to genetic variants as expression
quantitative trait loci is an expanding and useful approach, but focuses
exclusively on mRNA rather than protein levels. Many variants remain without
annotation. To address this problem, we measured the steady state abundance of
441 human signaling and transcription factor proteins from 68 Yoruba HapMap
lymphoblastoid cell lines to identify novel relationships between
inter-individual protein levels, genetic variants, and sensitivity to
chemotherapeutic agents. Proteins were measured using micro-western and reverse
phase protein arrays from three independent cell line thaws to permit mixed
effect modeling of protein biological replicates. We observed enrichment of
protein quantitative trait loci (pQTLs) for cellular sensitivity to two commonly
used chemotherapeutics: cisplatin and paclitaxel. We functionally validated the
target protein of a genome-wide significant trans-pQTL for its relevance in
paclitaxel-induced apoptosis. GWAS overlap results of drug-induced apoptosis and
cytotoxicity for paclitaxel and cisplatin revealed unique SNPs associated with
the pharmacologic traits (at p<0.001). Interestingly, GWAS SNPs from various
regions of the genome implicated the same target protein (p<0.0001) that
correlated with drug induced cytotoxicity or apoptosis (p ≤ 0.05). Two genes
were functionally validated for association with drug response using siRNA:
SMC1A with cisplatin response and ZNF569 with paclitaxel response. This work
allows pharmacogenomic discovery to progress from the transcriptome to the
proteome and offers potential for identification of new therapeutic targets.
This approach, linking targeted proteomic data to variation in pharmacologic
response, can be generalized to other studies evaluating genotype-phenotype
relationships and provide insight into chemotherapeutic mechanisms. Author information:
(1)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland; Institute for Information
Transmission Problems (Kharkevich Institute), Russian Academy of Sciences,
Moscow 127994, Russia. Electronic address: [email protected].
(2)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland; Swiss Institute of Bioinformatics,
1211 Geneva, Switzerland.
(3)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland; Swiss Institute of Bioinformatics,
1211 Geneva, Switzerland; New York Genome Center, Avenue of the Americas 101,
New York, NY 10013, USA; Department of Systems Biology, Columbia University,
1130 St. Nicholas Avenue, New York, NY 10032, USA.
(4)Medical Research Council Functional Genomics Unit, Department of Physiology,
Anatomy and Genetics, University of Oxford, Oxford OX1 3PT, UK; Wellcome Trust
Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
(5)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland.
(6)Institute for Information Transmission Problems (Kharkevich Institute),
Russian Academy of Sciences, Moscow 127994, Russia; School of Bioengineering and
Bioinformatics, Moscow State University, Vorobievy Gory 1-73, Moscow 119992,
Russia.
(7)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland; Swiss Institute of Bioinformatics,
1211 Geneva, Switzerland; Center of Excellence in Genomic Medicine Research,
King Abdulaziz University, Jeddah 21589, Saudi Arabia.
(8)Department of Genetic Medicine and Development, University of Geneva Medical
School, 1 Rue Michel-Servet, 1211 Geneva, Switzerland; Institute of Genetics and
Genomics in Geneva, 1211 Geneva, Switzerland. Electronic address:
[email protected]. |
What is Dysphoric Milk Ejection Reflex? | Dysphoric milk ejection reflex (D-MER) is characterized by an abrupt dysphoria, or undesirable feeling that occurs with the MER and continues for no more than a few minutes. After milk ejection, the dysphoria vanishes. Symptoms may decrease by 3 months or they may continue throughout the breastfeeding period. | Dysphoric Milk Ejection Reflex (D-MER) is an abrupt emotional "drop" that occurs
in some women just before milk release and continues for not more than a few
minutes. The brief negative feelings range in severity from wistfulness to
self-loathing, and appear to have a physiological cause. The authors suggest
that an abrupt drop in dopamine may occur when milk release is triggered,
resulting in a real or relative brief dopamine deficit for affected women.
Clinicians can support women with D-MER in several ways; often, simply knowing
that it is a recognized phenomenon makes the condition tolerable. Further study
is needed. BACKGROUND: Dysphoric milk ejection reflex (D-MER) is characterized by an abrupt
dysphoria, or undesirable feeling that occurs with the MER and continues for no
more than a few minutes. After milk ejection, the dysphoria vanishes.
CASE SERIES: This case series provides a report of three women who have
experienced D-MER. All three women described the sudden onset of negative
feelings at the initiation of each breastfeeding session. The dysphoria vanished
after each milk ejection.
DISCUSSION: Literature on D-MER is limited to one published qualitative research
study and two published case reports. As a result, lactation professionals and
other providers in the healthcare setting rarely recognize this condition.
CONCLUSIONS: The case studies presented here provide evidence for the presence
of D-MER. Research is needed to better understand its pathophysiology,
incidence, and treatment options. |
Is Rucaparib effective for ovarian cancer? | Yes. Rucaparib is an oral, small molecule, poly (ADP-ribose) polymerase inhibitor that has been approved for the treatment of patients with advanced ovarian cancer who have been treated with two or more chemotherapies and have a BRCA1 or BRCA2 gene mutation identified by an approved companion diagnostic test. | Here, we investigate the potential role of the PARP inhibitor rucaparib (CO-338,
formerly known as AG014699 and PF-01367338) for the treatment of sporadic
ovarian cancer. We studied the growth inhibitory effects of rucaparib in a panel
of 39 ovarian cancer cell lines that were each characterized for mutation and
methylation status of BRCA1/2, baseline gene expression signatures, copy number
variations of selected genes, PTEN status, and sensitivity to platinum-based
chemotherapy. To study interactions with chemotherapy, we used multiple drug
effect analyses and assessed apoptosis, DNA fragmentation, and γH2AX formation.
Concentration-dependent antiproliferative effects of rucaparib were seen in 26
of 39 (67%) cell lines and were not restricted to cell lines with BRCA1/2
mutations. Low expression of other genes involved in homologous repair (e.g.,
BCCIP, BRCC3, ATM, RAD51L1), amplification of AURKA or EMSY, and response to
platinum-based chemotherapy was associated with sensitivity to rucaparib. Drug
interactions with rucaparib were synergistic for topotecan, synergistic, or
additive for carboplatin, doxorubicin or paclitaxel, and additive for
gemcitabine. Synergy was most pronounced when rucaparib was combined with
topotecan, which resulted in enhanced apoptosis, DNA fragmentation, and γH2AX
formation. Importantly, rucaparib potentiated chemotherapy independent of its
activity as a single agent. PARP inhibition may be a useful therapeutic strategy
for a wider range of ovarian cancers bearing deficiencies in the homologous
recombination pathway other than just BRCA1/2 mutations. These results support
further clinical evaluation of rucaparib either as a single agent or as an
adjunct to chemotherapy for the treatment of sporadic ovarian cancer. Rucaparib camsylate (CO-338;
8-fluoro-2-{4-[(methylamino)methyl]phenyl}-1,3,4,5-tetrahydro-6H-azepino[5,4,3-cd]indol-6-one
((1S,4R)-7,7-dimethyl-2-oxobicyclo[2.2.1]hept-1-yl)methanesulfonic acid salt) is
a PARP1, 2 and 3 inhibitor. Phase I studies identified a recommended Phase II
dose of 600 mg orally twice daily. ARIEL2 Part 1 established a tumor genomic
profiling test for homologous recombination loss of heterozygosity
quantification using a next-generation sequencing companion diagnostic (CDx).
Rucaparib received US FDA Breakthrough Therapy designation for treatment of
platinum-sensitive BRCA-mutated advanced ovarian cancer patients who received
greater than two lines of platinum-based therapy. Comparable to rucaparib
development, other PARP inhibitors, such as olaparib, niraparib, veliparib and
talazoparib, are developing CDx tests for targeted therapy. PARP inhibitor
clinical trials and CDx assays are discussed in this review, as are potential
PARP inhibitor combination therapies and likely resistance mechanisms. 1. The FDA approved the PARP inhibitor rucaparib to treat women with advanced
ovarian cancer who have already been treated with at least two chemotherapies
and have a BRCA1 or BRCA2 gene mutation identified by an approved companion
diagnostic test. The agency also gave a nod to the FoundationFocus CDxBRCA test
to detect BRCA alterations. The nonradiologic medical management of solid tumors has evolved from the use of
traditional cytotoxic agents to modern targeted therapies, monoclonal
antibodies, and immunotherapies. Advances in the understanding of cancer biology
and therapeutic strategies have resulted in increasing numbers of new drug
applications and approvals. Consequently, practicing oncologists need to learn
how the newly available agents function and what toxicities to watch for, as
well as ways to optimize the use of both new drugs and previously approved drugs
with new indications. In 2016, the US Food and Drug Administration approved
three novel drugs for the treatment of solid maligcies-olaratumab in selected
patients with soft-tissue sarcoma, atezolizumab for the treatment of bladder
cancer, and rucaparib for the treatment of ovarian cancer; also in 2016, the use
of previously approved anticancer agents (including atezolizumab) was expanded
into 11 new patient populations. The diversity of options for patients is
evident in the broad range of the 2016 approvals, which include immune
checkpoint inhibitors, targeted therapies, monoclonal antibodies, and
traditional cytotoxic agents. This article focuses on the new agents and
indications that emerged in 2016 for solid tumor treatment. We review the drug
indications, mechanisms of action, pivotal trial data, pertinent toxicities, use
in special populations, and the appropriate clinical contexts for treatment
planning. Rucaparib (Rubraca™) is an oral, small molecule, poly (ADP-ribose) polymerase
inhibitor being developed by Clovis Oncology, Inc. (Boulder, CO, USA) for the
treatment of solid tumours. It has been approved in the USA as monotherapy for
the treatment of patients with deleterious BRCA mutation (germline and/or
somatic) associated advanced ovarian cancer who have been treated with two or
more chemotherapies. A marketing authorization application for rucaparib for the
same indication has been submitted to the European Medicines Agency. Rucaparib
is also under phase II or III investigation in ovarian, breast and prostate
cancer. This article summarizes the milestones in the development of rucaparib
leading to this first approval for ovarian cancer. Author information:
(1)Research Department of Oncology, UCL Cancer Institute, London, United
Kingdom. [email protected].
(2)Department of Medical Oncology, Dana-Farber Cancer Institute, Boston,
Massachusetts.
(3)Department of Medical Oncology, Sarah Cannon Research Institute, Tennessee
Oncology, PLLC, Nashville, Tennessee.
(4)Department of Obstetrics and Gynecology, Princess Margaret Cancer Centre,
University Health Network, Toronto, Ontario, Canada.
(5)Department of Medical Oncology, Yale University, New Haven, Connecticut.
(6)Department of Medical Oncology, Sarah Cannon Research Institute/Florida
Cancer Specialists, Sarasota, Florida.
(7)Department of Medical Oncology, Basser Center for BRCA, University of
Pennsylvania, Philadelphia, Pennsylvania.
(8)Department of Medical Oncology, Vall d'Hebron University Hospital and Vall
d'Hebron Institute of Oncology, Barcelona, Spain.
(9)Department of Medical Oncology, Northern Centre for Cancer Care, Newcastle
upon Tyne, United Kingdom.
(10)Department of Obstetrics, Gynecology, and Reproductive Sciences, Helen
Diller Family Comprehensive Cancer Center, University of California, San
Francisco, San Francisco, California.
(11)Department of Oncology, Tel Aviv Sourasky Medical Center, Tel Aviv, Israel.
(12)Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
(13)Department of Medical Oncology, Guy's Hospital, London, United Kingdom.
(14)Clinical Science, Clovis Oncology, Inc., Boulder, Colorado.
(15)Biostatistics, Clovis Oncology, Inc., Boulder, Colorado.
(16)Statistics and Data Management, Clovis Oncology, Inc., Boulder, Colorado.
(17)Clinical Pharmacology and Nonclinical DMPK, Clovis Oncology, Inc., Boulder,
Colorado.
(18)Clinical Development, Clovis Oncology, Inc., Boulder, Colorado.
(19)Clinical and Preclinical Development, Clovis Oncology, Inc., Boulder,
Colorado.
(20)Department of Oncology, Sheba Medical Center, Ramat Gan, Israel. On December 19, 2016, the FDA granted accelerated approval to rucaparib
(RUBRACA; Clovis Oncology, Inc.) for the treatment of patients with deleterious
BRCA mutation (germline and/or somatic)-associated advanced ovarian cancer who
have been treated with two or more chemotherapies. The FDA also approved the
FoundationFocus CDx BRCA test (Foundation Medicine, Inc.), the first
next-generation sequencing-based companion diagnostic, for identifying patients
with advanced ovarian cancer eligible for treatment with rucaparib based on
detection of deleterious BRCA1 and/or BRCA2 mutations in tumor tissue.
Rucaparib's approval was based primarily on efficacy data from 106 patients with
BRCA mutation-associated ovarian cancer who had prior treatment with two or more
chemotherapies and safety data from 377 patients with ovarian cancer treated
with rucaparib 600 mg orally twice daily on two open-label, single-arm trials.
Investigator-assessed objective response rate was 54% [57/106; 95% confidence
interval (CI), 44-64], and median duration of response was 9.2 months (95% CI,
6.6-11.7). The approved companion diagnostic verified tumor BRCA mutation status
retrospectively in 96% (64/67) of patients. Common adverse reactions (≥20%) to
rucaparib were nausea, fatigue, vomiting, anemia, abdominal pain, dysgeusia,
constipation, decreased appetite, diarrhea, thrombocytopenia, and dyspnea. This
article summarizes the FDA review and data supporting rucaparib's accelerated
approval. Clin Cancer Res; 23(23); 7165-70. ©2017 AACRSee related commentary by
Kohn et al., p. 7155. Rucaparib camsylate (CO-338, AG-014699, PF-01367338) is a potent PARP-1, PARP-2,
and PARP-3 inhibitor. Phase I and II studies demonstrated clinical efficacy in
both BRCA-mutated (inclusive of germline and somatic) ovarian tumors and ovarian
tumors with homologous recombination deficiency (HRD) loss of heterozygosity
(LOH). Rucaparib has received the US Food and Drug Administration (FDA) approval
for patients with deleterious BRCA mutation (germline and/or somatic)-associated
advanced ovarian cancer who have been treated with two or more chemotherapies.
There is evidence to suggest that rucaparib has clinical efficacy against
ovarian tumors with high HRD-LOH. Rucaparib's companion diagnostic
FoundationFocus™ CDx BRCA test is the first FDA-approved next-generation
sequencing-based companion diagnostic test designed to identify patients likely
to respond to rucaparib. This article reviews the mechanisms of action, safety,
approval, and indications for use of the PARP inhibitor rucaparib as well as
future trials and use of rucaparib's companion diagnostic test. BACKGROUND: Rucaparib, a poly(ADP-ribose) polymerase inhibitor, has anticancer
activity in recurrent ovarian carcinoma harbouring a BRCA mutation or high
percentage of genome-wide loss of heterozygosity. In this trial we assessed
rucaparib versus placebo after response to second-line or later platinum-based
chemotherapy in patients with high-grade, recurrent, platinum-sensitive ovarian
carcinoma.
METHODS: In this randomised, double-blind, placebo-controlled, phase 3 trial, we
recruited patients from 87 hospitals and cancer centres across 11 countries.
Eligible patients were aged 18 years or older, had a platinum-sensitive,
high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube
carcinoma, had received at least two previous platinum-based chemotherapy
regimens, had achieved complete or partial response to their last platinum-based
regimen, had a cancer antigen 125 concentration of less than the upper limit of
normal, had a performance status of 0-1, and had adequate organ function.
Patients were ineligible if they had symptomatic or untreated central nervous
system metastases, had received anticancer therapy 14 days or fewer before
starting the study, or had received previous treatment with a poly(ADP-ribose)
polymerase inhibitor. We randomly allocated patients 2:1 to receive oral
rucaparib 600 mg twice daily or placebo in 28 day cycles using a
computer-generated sequence (block size of six, stratified by homologous
recombination repair gene mutation status, progression-free interval after the
penultimate platinum-based regimen, and best response to the most recent
platinum-based regimen). Patients, investigators, site staff, assessors, and the
funder were masked to assignments. The primary outcome was investigator-assessed
progression-free survival evaluated with use of an ordered step-down procedure
for three nested cohorts: patients with BRCA mutations (carcinoma associated
with deleterious germline or somatic BRCA mutations), patients with homologous
recombination deficiencies (BRCA mutant or BRCA wild-type and high loss of
heterozygosity), and the intention-to-treat population, assessed at screening
and every 12 weeks thereafter. This trial is registered with ClinicalTrials.gov,
number NCT01968213; enrolment is complete.
FINDINGS: Between April 7, 2014, and July 19, 2016, we randomly allocated 564
patients: 375 (66%) to rucaparib and 189 (34%) to placebo. Median
progression-free survival in patients with a BRCA-mutant carcinoma was 16·6
months (95% CI 13·4-22·9; 130 [35%] patients) in the rucaparib group versus 5·4
months (3·4-6·7; 66 [35%] patients) in the placebo group (hazard ratio 0·23 [95%
CI 0·16-0·34]; p<0·0001). In patients with a homologous recombination deficient
carcinoma (236 [63%] vs 118 [62%]), it was 13·6 months (10·9-16·2) versus 5·4
months (5·1-5·6; 0·32 [0·24-0·42]; p<0·0001). In the intention-to-treat
population, it was 10·8 months (8·3-11·4) versus 5·4 months (5·3-5·5; 0·36
[0·30-0·45]; p<0·0001). Treatment-emergent adverse events of grade 3 or higher
in the safety population (372 [99%] patients in the rucaparib group vs 189
[100%] in the placebo group) were reported in 209 (56%) patients in the
rucaparib group versus 28 (15%) in the placebo group, the most common of which
were anaemia or decreased haemoglobin concentration (70 [19%] vs one [1%]) and
increased alanine or aspartate aminotransferase concentration (39 [10%] vs
none).
INTERPRETATION: Across all primary analysis groups, rucaparib significantly
improved progression-free survival in patients with platinum-sensitive ovarian
cancer who had achieved a response to platinum-based chemotherapy. ARIEL3
provides further evidence that use of a poly(ADP-ribose) polymerase inhibitor in
the maintece treatment setting versus placebo could be considered a new
standard of care for women with platinum-sensitive ovarian cancer following a
complete or partial response to second-line or later platinum-based
chemotherapy.
FUNDING: Clovis Oncology. INTRODUCTION: Poly(ADP-ribose) polymerase (PARP) inhibitors are a targeted
therapy option for ovarian cancer. The goal of this review was to organize and
summarize the clinical trials evaluating PARP inhibitor therapy in ovarian
cancer as monotherapy, maintece therapy after partial or complete remission
to therapy or as a part of a combination regimen.
EVIDENCE ACQUISITION: PubMed, ClinicalTrials.gov, data from the United States
Food and Drug Administration (US FDA) and proceedings from scientific
conferences were searched for published and unpublished data pertaining to
clinical trials and approvals of PARP inhibitor use in ovarian cancer.
EVIDENCE SYNTHESIS: There have been 36 published phase 1, 2 and 3 studies
evaluating the use of olaparib, niraparib, veliparib and rucaparib in ovarian
cancer. Olaparib and rucaparib have been approved by the US FDA as monotherapy
for advanced recurrent ovarian cancer. Niraparib and olaparib have been approved
by the US FDA for maintece therapy after partial or complete remission in
recurrent ovarian cancer. There are currently ten phase 3 trials evaluating PARP
inhibitors at various timepoints in ovarian cancer therapy including at the time
of primary adjuvant therapy, as maintece therapy after primary chemotherapy,
as monotherapy for recurrent cancer and as maintece therapy after
chemotherapy for recurrence.
CONCLUSIONS: The landscape of PARP inhibitor use for ovarian cancer is rapidly
evolving and PARP inhibitors have become more available as a targeted therapy
option for ovarian cancer treatment. OBJECTIVE: To review the pharmacology, safety, efficacy, and the role of
rucaparib in the treatment of relapsed, advanced ovarian cancer.
SUMMARY: A total of 2 phase I/II trials and 1 phase II trial have evaluated the
safety and efficacy of oral rucaparib in ovarian cancer. In patients with
deleterious BRCA1/2 mutation, an overall response rate of 80% was achieved in
the phase II trial Assessment of Rucaparib in Ovarian CancEr Trial 2 (ARIEL2).
In the same trial, progression-free survival was higher in patients with BRCA1/2
mutation and BRCA wild types with high loss of heterozygosity (LOH) than BRCA
wild types with low LOH. Rucaparib was found to be relatively well tolerated in
clinical trials, with the most common adverse events being anemia, fatigue, and
nausea.
CONCLUSION: Rucaparib appears to be a safe and effective new option in the
treatment of relapsed, advanced BRCA1/2 mutant ovarian cancer. The role of
rucaparib in this setting will likely expand and be further elucidated as
results from several ongoing studies become available. |
What is the "protein inference problem"? | A major challenge in shotgun proteomics has been the assignment of identified peptides to the proteins from which they originate, referred to as the protein inference problem. | A major challenge in shotgun proteomics has been the assignment of identified
peptides to the proteins from which they originate, referred to as the protein
inference problem. Redundant and homologous protein sequences present a
challenge in being correctly identified, as a set of peptides may in many cases
represent multiple proteins. One simple solution to this problem is the
assignment of the smallest number of proteins that explains the identified
peptides. However, it is not certain that a natural system should be accurately
represented using this minimalist approach. In this paper, we propose a
reformulation of the protein inference problem by utilizing the recently
introduced concept of peptide detectability. We also propose a heuristic
algorithm to solve this problem and evaluate its performance on synthetic and
real proteomics data. In comparison to a greedy implementation of the minimum
protein set algorithm, our solution that incorporates peptide detectability
performs favorably. MOTIVATION: Assembling peptides identified from tandem mass spectra into a list
of proteins, referred to as protein inference, is an important issue in shotgun
proteomics. The objective of protein inference is to find a subset of proteins
that are truly present in the sample. Although many methods have been proposed
for protein inference, several issues such as peptide degeneracy still remain
unsolved.
RESULTS: In this article, we present a linear programming model for protein
inference. In this model, we use a transformation of the joint probability that
each peptide/protein pair is present in the sample as the variable. Then, both
the peptide probability and protein probability can be expressed as a formula in
terms of the linear combination of these variables. Based on this simple fact,
the protein inference problem is formulated as an optimization problem: minimize
the number of proteins with non-zero probabilities under the constraint that the
difference between the calculated peptide probability and the peptide
probability generated from peptide identification algorithms should be less than
some threshold. This model addresses the peptide degeneracy issue by forcing
some joint probability variables involving degenerate peptides to be zero in a
rigorous manner. The corresponding inference algorithm is named as ProteinLP. We
test the performance of ProteinLP on six datasets. Experimental results show
that our method is competitive with the state-of-the-art protein inference
algorithms.
AVAILABILITY: The source code of our algorithm is available at:
https://sourceforge.net/projects/prolp/.
CONTACT: [email protected].
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
Online. Protein inference is an important issue in proteomics research. Its main
objective is to select a proper subset of candidate proteins that best explain
the observed peptides. Although many methods have been proposed for solving this
problem, several issues such as peptide degeneracy and one-hit wonders still
remain unsolved. Therefore, the accurate identification of proteins that are
truly present in the sample continues to be a challenging task. Based on the
concept of peptide detectability, we formulate the protein inference problem as
a constrained Lasso regression problem, which can be solved very efficiently
through a coordinate descent procedure. The new inference algorithm is named as
ProteinLasso, which explores an ensemble learning strategy to address the
sparsity parameter selection problem in Lasso model. We test the performance of
ProteinLasso on three datasets. As shown in the experimental results,
ProteinLasso outperforms those state-of-the-art protein inference algorithms in
terms of both identification accuracy and running efficiency. In addition, we
show that ProteinLasso is stable under different parameter specifications. The
source code of our algorithm is available at:
http://sourceforge.net/projects/proteinlasso. In mass spectrometry-based shotgun proteomics, protein quantification and
protein identification are two major computational problems. To quantify the
protein abundance, a list of proteins must be firstly inferred from the raw
data. Then the relative or absolute protein abundance is estimated with
quantification methods, such as spectral counting. Until now, most researchers
have been dealing with these two processes separately. In fact, the protein
inference problem can be regarded as a special protein quantification problem in
the sense that truly present proteins are those proteins whose abundance values
are not zero. Some recent published papers have conceptually discussed this
possibility. However, there is still a lack of rigorous experimental studies to
test this hypothesis. In this paper, we investigate the feasibility of using
protein quantification methods to solve the protein inference problem. Protein
inference methods aim to determine whether each candidate protein is present in
the sample or not. Protein quantification methods estimate the abundance value
of each inferred protein. Naturally, the abundance value of an absent protein
should be zero. Thus, we argue that the protein inference problem can be viewed
as a special protein quantification problem in which one protein is considered
to be present if its abundance is not zero. Based on this idea, our paper tries
to use three simple protein quantification methods to solve the protein
inference problem effectively. The experimental results on six data sets show
that these three methods are competitive with previous protein inference
algorithms. This demonstrates that it is plausible to model the protein
inference problem as a special protein quantification task, which opens the door
of devising more effective protein inference algorithms from a quantification
perspective. The source codes of our methods are available at:
http://code.google.com/p/protein-inference/. |
What is the link between lithium use during pregnancy and Ebstein anomaly? | It is generally believed that lithium use is associated with increased risk of Ebstein anomaly. However, more recent studies challenge this association. | Lithium carbonate is an effective drug for prophylaxis and treatment of major
affective disorders. In-utero exposure to lithium during the first trimester of
pregcy might be associated with an increased risk of cardiac malformations,
especially the rare Ebstein's anomaly. We prospectively recruited and followed
148 women (mean age 30 years, SD 5 range 15-40) using lithium during the first
trimester of pregcy, who consulted four teratogen information centres in the
USA and Canada. Pregcy outcome was compared with that of controls matched for
maternal age. We had complete follow-up of pregcy outcome in 138 of 148
patients recruited. In the other 10, fetal echocardiograms were available but
postnatal follow-up was not done. Mean daily dose of lithium was 927 mg (SD
340). Rates of major congenital malformations did not differ between the lithium
(2.8%) and control (2.4%) groups. 1 patient in the lithium group chose to
terminate pregcy after Ebstein's anomaly was detected by a prenatal
echocardiogram. There was 1 ventricular septal defect in the controls.
Birthweight was significantly higher in the lithium-exposed infants than in the
controls despite identical gestational ages (3475 [660] g vs 3383 [566] g, p =
0.02). The true difference in birthweight might have been even larger, since
significantly more women using lithium than controls were cigarette smokers
(31.8% vs 15.5%, p = 0.002). These results indicate that lithium is not an
important human teratogen. Women with major affective disorders who wish to have
children may continue lithium therapy, provided that adequate screening tests,
including level II ultrasound and fetal echocardiography, are done. The literature in most European languages was consulted for guidelines regarding
the drug treatment of psychiatrically disturbed pregt or lactating women. The
available information allows only a few conclusions. Lithium exposure during the
first trimester seems to increase the risk of congenital heart disease,
especially Ebstein's anomaly. As there is still insufficient evidence to prove
the safeness of other psychoactive drugs for the fetus, caution seems warranted
here too. A causal link between pharmacotherapy of the mother-to-be and
malformation of the baby is difficult to prove. But toxic and withdrawal
symptoms in infants born to women treated regularly until shortly before
confinement are well documented for most psychoactive drugs. Ebstein's anomaly is characterised by downward displacement of the tricuspid
valve into the right ventricle. The most deformed leaflets are the septal and
mural ones. The abnormally situated tricuspid orifice produces a portion of the
right ventricle lying between the atrioventricular ring and the origin of the
valve. This proximal segment is atrialized. Commonly associated anatomical
defects include a atrial septal second defect, a ventricular septal defect,
pulmonary stenosis or atresia, and mitral valve prolapse. An accessory
conduction pathway (Wolf-Parkinson White syndrome) was found in this
malformation. It is thought that this malformation is due to a direct
teratogenic effect of lithium on the atrioventricular junction. Ebstein's
anomaly can be accurately identified by echocardiography and angiography. OBJECTIVE: To reevaluate the risk associated with in utero exposure to lithium.
DATA SOURCES AND STUDY SELECTION: Data were obtained from all published studies,
in multiple languages, referenced in MEDLINE, Toxline, and the Lithium
Information Center databases. Unpublished studies were not included. The search
terms were lithium, pregcy, teratogen, abnormalities (drug induced),
Ebstein's anomaly, and adverse effects.
DATA EXTRACTION AND SYNTHESIS: In the 1970s a very strong association was
suggested between maternal lithium treatment during pregcy and Ebstein's
anomaly of the heart in the offspring. The relative risk for Ebstein's anomaly
among such children was estimated to be 400 on the basis of data collected from
a registry of voluntarily submitted cases. More recent controlled epidemiologic
studies have consistently shown a lower risk. No women who took lithium during
pregcy were found among four case-control studies of Ebstein's anomaly
involving 25, 34, 59, and 89 affected children, respectively. In two cohort
studies, risk ratios of 3.0 (95% confidence interval [CI], 1.2 to 7.7) and 1.5
(95% CI, 0.4 to 6.8) for all congenital anomalies have been observed. The risk
ratios for cardiac malformations in these studies were 7.7 (95% CI, 1.5 to 41.2)
and 1.2 (95% CI, 0.1 to 18.3), respectively.
CONCLUSION: While initial information regarding the teratogenic risk of lithium
treatment was derived from biased retrospective reports, more recent
epidemiologic data indicate that the teratogenic risk of first-trimester lithium
exposure is lower than previously suggested. The clinical management of women
with bipolar disorder who have childbearing potential should be modified with
this revised risk estimate. The purpose of this study was to review the use of lithium in pregcy and its
effects on the neonate. This was a case study and review of the published
literature. Lithium is commonly used in the treatment of psychiatric disorders,
specifically bipolar depression. Bipolar disorders that require treatment with
lithium demand special consideration when the woman becomes pregt. Reported
neonatal problems with maternal lithium therapy include Ebstein's anomaly, poor
respiratory effort and cyanosis, rhythm disturbances, nephrogenic diabetes
insipidus, thyroid dysfunction, hypoglycemia, hypotonia and lethargy,
hyperbilirubinemia, and large-for-gestational-age infants. Lithium can have
adverse effects on the fetus and newborn infant, but data suggest normal
behavioral patterns in childhood. Ebstein anomaly (EA) is a congenital defect of the tricuspid valve (TV) and the
right ventricle (RV) in which the attachments of the septal and posterior valve
leaflets are apically displaced. The latter creates 3 morphologic components
inside the right heart, namely the right atrium proper, the atrialized RV, and
the functional RV. This rare anomaly accounts for <1.5% of all congenital heart
diseases. The current opinion among authors is that it is a genetically
heterogeneous condition caused by failure of delamination of the TV leaflets
from the underlying myocardium and the interventricular septum. Its
characteristic electrocardiographic findings include tall, broad, right atrial P
waves, prolonged PR intervals, and deep Q waves in the right precordial leads.
Echocardiography is currently the best technique for diagnosing this anomaly,
although cardiac magnetic resoce imaging is also gaining traction as an
alternative modality. The management strategies for EA correlate with the age of
the patient, severity of the heart disease, and/or associated cardiac
abnormalities. TV repair, rather than valve replacement, is preferred because of
its favorable long-term prognosis. Nevertheless, a large, randomized study is
still needed to compare the different valve repair techniques used in patients
with EA. OBJECTIVES: The aim of this study was to describe the epidemiology of Ebstein's
anomaly in Europe and its association with maternal health and medication
exposure during pregcy.
DESIGN: We carried out a descriptive epidemiological analysis of
population-based data.
SETTING: We included data from 15 European Surveillance of Congenital Anomalies
Congenital Anomaly Registries in 12 European countries, with a population of 5.6
million births during 1982-2011. Participants Cases included live births, fetal
deaths from 20 weeks gestation, and terminations of pregcy for fetal anomaly.
Main outcome measures We estimated total prevalence per 10,000 births. Odds
ratios for exposure to maternal illnesses/medications in the first trimester of
pregcy were calculated by comparing Ebstein's anomaly cases with cardiac and
non-cardiac malformed controls, excluding cases with genetic syndromes and
adjusting for time period and country.
RESULTS: In total, 264 Ebstein's anomaly cases were recorded; 81% were live
births, 2% of which were diagnosed after the 1st year of life; 54% of cases with
Ebstein's anomaly or a co-existing congenital anomaly were prenatally diagnosed.
Total prevalence rose over time from 0.29 (95% confidence interval (CI)
0.20-0.41) to 0.48 (95% CI 0.40-0.57) (p<0.01). In all, nine cases were exposed
to maternal mental health conditions/medications (adjusted odds ratio (adjOR)
2.64, 95% CI 1.33-5.21) compared with cardiac controls. Cases were more likely
to be exposed to maternal β-thalassemia (adjOR 10.5, 95% CI 3.13-35.3, n=3) and
haemorrhage in early pregcy (adjOR 1.77, 95% CI 0.93-3.38, n=11) compared
with cardiac controls.
CONCLUSIONS: The increasing prevalence of Ebstein's anomaly may be related to
better and earlier diagnosis. Our data suggest that Ebstein's anomaly is
associated with maternal mental health problems generally rather than lithium or
benzodiazepines specifically; therefore, changing or stopping medications may
not be preventative. We found new associations requiring confirmation. BACKGROUND: There has been concern that exposure to lithium early in pregcy
may be associated with a marked increase in the risk of Ebstein's anomaly (a
right ventricular outflow tract obstruction defect) in infants and overall
congenital cardiac defects, but data are conflicting and limited.
METHODS: We conducted a cohort study involving 1,325,563 pregcies in women
who were enrolled in Medicaid and who delivered a live-born infant between 2000
and 2010. We examined the risk of cardiac malformations among infants exposed to
lithium during the first trimester as compared with unexposed infants and, in
secondary analyses, with infants exposed to another commonly used mood
stabilizer, lamotrigine. Risk ratios and 95% confidence intervals were estimated
with control for psychiatric and medical conditions, medications, and other
potential confounders.
RESULTS: Cardiac malformations were present in 16 of the 663 infants exposed to
lithium (2.41%), 15,251 of the 1,322,955 nonexposed infants (1.15%), and 27 of
the 1945 infants exposed to lamotrigine (1.39%). The adjusted risk ratio for
cardiac malformations among infants exposed to lithium as compared with
unexposed infants was 1.65 (95% confidence interval [CI], 1.02 to 2.68). The
risk ratio was 1.11 (95% CI, 0.46 to 2.64) for a daily dose of 600 mg or less,
1.60 (95% CI, 0.67 to 3.80) for 601 to 900 mg, and 3.22 (95% CI, 1.47 to 7.02)
for more than 900 mg. The prevalence of right ventricular outflow tract
obstruction defects was 0.60% among lithium-exposed infants versus 0.18% among
unexposed infants (adjusted risk ratio, 2.66; 95% CI, 1.00 to 7.06). Results
were similar when lamotrigine-exposed infants were used as the reference group.
CONCLUSIONS: Maternal use of lithium during the first trimester was associated
with an increased risk of cardiac malformations, including Ebstein's anomaly;
the magnitude of this effect was smaller than had been previously postulated.
(Funded by the National Institute of Mental Health.). |
Does verubecestat activate BACE? | No, verubecestat is a potent BACE inhibitor. | |
What does the Ribosome-bound Quality Control complex do? | Ribosome-bound Quality Control complex (RQC), which recognizes nascent peptides translated from aberrant mRNAs, polyubiquitylates these aberrant peptides, extracts them from the stalled 60S subunit and finally escorts them to the proteasome for degradation. | Proteostasis in eukaryotes is maintained by compartment-specific quality control
pathways, which enable the refolding or the degradation of defective
polypeptides to prevent the toxicity that may arise from their aggregation.
Among these processes, translational protein quality control is performed by the
Ribosome-bound Quality Control complex (RQC), which recognizes nascent peptides
translated from aberrant mRNAs, polyubiquitylates these aberrant peptides,
extracts them from the stalled 60S subunit and finally escorts them to the
proteasome for degradation. In this review, we focus on the mechanism of action
of the RQC complex from stalled 60S binding to aberrant peptide delivery to the
proteasome and describe the cellular consequences of a deficiency in the RQC
pathway, such as aberrant protein aggregation. In addition, this review covers
the recent discoveries concerning the role of cytosolic chaperones, as well as
Tom1, to prevent the accumulation of aberrant protein aggregates in case of a
deficiency in the RQC pathway. |
What is emicizumab? | ACE910 (emicizumab) is a humanized bispecific antibody recognizing factor IXa and X mimicking factor VIII function. | The development of inhibitors to factor VIII (FVIII) or factor IX (FIX) remains
a major treatment complication encountered in the treatment of haemophilia. Not
all patients with even the same severity and genotype develop inhibitors
suggesting an underlying mechanism of tolerance against FVIII- or FIX-related
immunity. One mechanism may be central tolerance observed in patients in whom
the FVIII mutation enables some production of the protein. The other is a
peripheral tolerance mechanism which may be evident in patients with null
mutation. Recently, recombit porcine FVIII (rpFVIII, Obixur, OBI-1, BAX801)
has been developed for the haemostatic treatment of both congenital haemophilia
with inhibitor (CHAWI) and acquired haemophilia A (AHA). In 28 subjects with AHA
with life-/limb-threatening bleeding, rpFVIII reduced or stopped bleeding in all
patients within 24 h. The cross-reactivity of anti-human FVIII antibodies to
rpFVIII remains around 30-50%. Recently, new therapeutics based on the quite
novel concepts have been developed and clinical studies are ongoing. These are
humanized asymmetric antibody mimicking FVIIIa function by maintaining a
suitable interaction between FIXa and FX (Emicizumab, ACE910), and small
interfering RNAs (siRNA, ALN-AT3) suppress liver production of AT through
post-transcriptional gene silencing and a humanized anti-TFPI monoclonal
antibody (Concizumab). Their main advantages are longer half-life, subcutaneous
applicability and efficacy irrespective of the presence of inhibitors which will
make it easier to initiate more effective treatment especially early childhood. The principle of hemophilia treatment is replacement therapy with factor VIII
and factor IX concentrates. Recently, extended half-life factor VIII and factor
IX concentrates have been developed. With these concentrates, improvements in
patient QOL can be expected. More recently, a novel hemophilia therapy based on
a very new concept was developed. ACE910 (emicizumab) is a humanized bispecific
antibody recognizing factor IXa and X mimicking factor VIII function. The
half-life is reportedly 4-5 weeks and remarkably decreased annual bleeding rates
have been achieved with subcutaneous weekly injections in the phase 1 clinical
trial. Clinical trials of anti-antithrombin therapeutics based on siRNA
(ALN-AT3) and anti-TFPI antibody are currently ongoing and the results are
eagerly anticipated. During the last decade, the development of improved and novel approaches for the
treatment of hemophilia A has expanded tremendously. These approaches include
factor VIII (FVIII) with extended half-life (eg, FVIII-Fc and PEGylated FVIII),
monoclonal antibodies targeting tissue factor pathway inhibitor, small
interfering RNA to reduce antithrombin expression and the bispecific antibody
ACE910/emicizumab. Emicizumab is a bispecific antibody recognizing both the
enzyme factor IXa and the substrate factor X. By simultaneously binding enzyme
and substrate, emicizumab mimics some part of the function exerted by the
original cofactor, FVIII, in that it promotes colocalization of the
enzyme-substrate complex. However, FVIII and the bispecific antibody are
fundamentally different proteins and subject to different modes of regulation.
Here, we will provide an overview of the similarities and dissimilarities
between FVIII and emicizumab from a biochemical and mechanistical perspective.
Such insight might be useful in the clinical decision making for those who apply
emicizumab in their practice now or in the future, particularly in view of the
thrombotic complications that have been reported when emicizumab is used in
combination with FVIII-bypassing agents. |
What illness is transmitted by the Lone Star Tick, Amblyomma americanum? | Amblyomma americanum (Lone star tick) is an important disease vector in the United States. It transmits several human pathogens, including the agents of human monocytic ehrlichiosis, tularemia, and southern tick-associated rash illness [STARI] or Masters disease | Amblyomma americanum is an aggressive ixodid tick that has been implicated as a
vector for several bacterial agents. Among these is Ehrlichia chaffeensis, which
causes human monocytic (or monocytotropic) ehrlichiosis. In this study,
experimental tick transmission of E. chaffeensis from infected lone star ticks
to deer was revisited, and the question of whether it would be possible to
re-isolate the organism from deer was asked, because this had not been done
previously. Here, we were able to transmit a wild strain of E. chaffeensis from
acquisition-fed lone star ticks to white-tailed deer. Ehrlichia chaffeensis was
re-isolated from one white-tailed deer on multiple days during the infection and
from another deer on one day during the infection. Peak rickettsemias for E.
chaffeensis-infected deer were 17 DPI with acquisition-fed ticks and 14 DPI with
needle-inoculated deer. This study supports the role of the lone star tick and
white-tailed deer as vector and reservoir host for E. chaffeensis, demonstrating
culture re-isolation of E. chaffeensis in deer infected by experimental tick
transmission for the first time. We reviewed scientific literature pertaining to known and putative disease
agents associated with the lone star tick, Amblyomma americanum. Reports in the
literature concerning the role of the lone star tick in the transmission of
pathogens of human and animal diseases have sometimes been unclear and even
contradictory. This overview has indicated that A. americanum is involved in the
ecology of several disease agents of humans and other animals, and the role of
this tick as a vector of these diseases ranges from incidental to significant.
Probably the clearest relationship is that of Ehrlichia chaffeensis and A.
americanum. Also, there is a definite association between A. americanum and
tularemia, as well as between the lone star tick and Theileria cervi to
white-tailed deer. Evidence of Babesia cervi (= odocoilei) being transmitted to
deer by A. americanum is largely circumstantial at this time. The role of A.
americanum in cases of southern tick-associated rash illness (STARI) is
currently a subject of intensive investigations with important implications. The
lone star tick has been historically reported to be a vector of Rocky Mountain
spotted fever rickettsiae, but current opinions are to the contrary. Evidence
incriminated A. americanum as the vector of Bullis fever in the 1940s, but the
disease apparently has disappeared. Q fever virus has been found in unfed A.
americanum, but the vector potential, if any, is poorly understood at this time.
Typhus fever and toxoplasmosis have been studied in the lone star tick, and
several non-pathogenic organisms have been recovered. Implications of these
tick-disease relationships are discussed. Ehrlichia chaffeensis, an intracellular gram-negative zoonotic bacterium, is the
causative agent of human monocytotropic ehrlichiosis (HME). In humans, the
disease can range from a mild, non-specific illness with few to no clinical
signs to a moderately severe to fatal disease, especially those with compromised
immune systems. E. chaffeensis is maintained in a complex cycle involving
white-tailed deer (WTD; Odocoileus virginianus) as a primary reservoir and the
lone star tick (LST; Amblyomma americanum) as a primary vector. Numerous other
species are naturally exposed to E. chaffeensis and disease has been documented
in some domestic animals and wildlife including domestic dogs and ring-tailed
lemurs. The organism has been found throughout the natural range of the LST and
as the tick continues to expand its range, the geographic range of risk for E.
chaffeensis infections will likely continue to expand. Recent data have
indicated that E. chaffeensis, or a closely related organism, has been found in
many species of ticks and vertebrate hosts in numerous countries. Southern tick-associated rash illness is a Lyme-like syndrome that occurs in the
southern states. Borrelia lonestari, which has been suggested as a possible
causative agent of southern tick-associated rash illness, naturally infects
white-tailed deer (WTD; Odocoileus virginianus) and is transmitted by the lone
star tick (Amblyomma americanum). To better understand the prevalence and
distribution of Borrelia exposure among WTD, we tested WTD from 21 eastern
states for antibodies reactive to B. lonestari using an indirect
immunofluorescent antibody assay and Borrelia burgdorferi using the IDEXX SNAP
4Dx test. A total of 107/714 (15%) had antibodies reactive to B. lonestari, and
prevalence of antibodies was higher in deer from southern states (17.5%) than in
deer from northern states (9.2%). Using the SNAP 4DX test, we found that 73/723
(10%) were positive for B. burgdorferi, and significantly more northern deer
(23.9%) were positive compared with southern deer (3.8%). Our data demonstrate
that WTD are exposed to both Borrelia species, but antibody prevalence for
exposure to the two species differs regionally and distributions correlate with
the presence of Ixodes scapularis and A. americanum ticks. The most common clinical manifestation of Lyme disease is the characteristic
rash, erythema migrans (EM). In the 1980s EM-like eruptions were reported in
Missouri and other southeastern states. The EM-like eruptions, which were of
unknown etiology, often followed the bite of the Lone Star tick (Amblyomma
americanum) and the rash is called STARI (southern tick-associated rash
illness). Although the Lone Star tick is found in the Lyme disease-endemic areas
of New England and Mid-Atlantic regions of the United States, STARI has been
reported only once from the Northeast and Mid-Atlantic regions. We report a
child from Connecticut who visited Long Island, New York, and developed a rash
that was thought to be EM. Because the patient failed to respond to antibiotics
used to treat Lyme disease, an investigation ensued, and the diagnosis of STARI
was established. Amblyomma americanum, the lone star tick, is the most common and most aggressive
human biting tick in the Southeastern United States. It is known to transmit the
agents of human ehrlichioses, Ehrlichia chaffeensis and Ehrlichia ewingii. In
addition, it carries agents of unspecified pathogenicity to humans, including
Rickettsia amblyommii, Borrelia lonestari, and the newly emerging Panola
Mountain Ehrlichia (PME). Surveillance of these ticks for recognized or emerging
pathogens is necessary for assessing the risk of human infection. From 2005 to
2009, we surveyed A. americanum ticks from four locations in the state of
Georgia. Ticks (1,183 adults, 2,954 nymphs, and 99 larval batches) were tested
using a multiplex real-time polymerase chain reaction (PCR) assay designed to
detect and discriminate DNA from Rickettsia spp., E. chaffeensis, and E.
ewingii. This assay was capable of detecting as few as 10 gene copies of the
aforementioned agents. Ticks were also tested for PME and B. lonestari by nested
PCR. The prevalence of infection ranged from 0 to 2.5% for E. chaffeensis, 0 to
3.9% for E. ewingii, 0 to 2.2% for PME, 17 to 83.1% for R. amblyommii, and 0 to
3.1% for B. lonestari. There were 46 (4.1%) individual adults positive for two
agents, and two females that were each positive for three agents. Two larval
batches were positive for both B. lonestari and R. amblyommii, indicating the
potential for transovarial transmission of both agents from a single female.
Although infrequent in occurrence, the dynamics of coinfections in individual
ticks should be explored further, given the potential implications for
differential diagnosis and severity of human illness. Amblyomma americanum (Lone star tick) is an important disease vector in the
United States. It transmits several human pathogens, including the agents of
human monocytic ehrlichiosis, tularemia, and southern tick-associated rash
illness. Blood-feeding insects (Class Insecta) depend on bacterial endosymbionts
to provide vitamins and cofactors that are scarce in blood. It is unclear how
this deficiency is compensated in ticks (Class Arachnida) that feed exclusively
on mammalian blood. A bacterium related to Coxiella burnetii, the agent of human
Q fever, has been observed previously within cells of A. americanum. Eliminating
this bacterium (CLEAA, Coxiella-like endosymbiont of A. americanum) with
antibiotics reduced tick fecundity, indicating that it is an essential
endosymbiont. In an effort to determine its role within this symbiosis, we
sequenced the CLEAA genome. While highly reduced (656,901 bp) compared with C.
burnetii (1,995,281 bp), the CLEAA genome encodes most major vitamin and
cofactor biosynthesis pathways, implicating CLEAA as a vitamin provisioning
endosymbiont. In contrast, CLEAA lacks any recognizable virulence genes,
indicating that it is not a pathogen despite its presence in tick salivary
glands. As both C. burnetii and numerous "Coxiella-like bacteria" have been
reported from several species of ticks, we determined the evolutionary
relationship between the two bacteria. Phylogeny estimation revealed that CLEAA
is a close relative of C. burnetii, but was not derived from it. Our results are
important for strategies geared toward controlling A. americanum and the
pathogens it vectors, and also contribute novel information regarding the
metabolic interdependencies of ticks and their nutrient-provisioning
endosymbionts. Monocytic ehrlichiosis in people caused by the intracellular bacterium,
Ehrlichia chaffeensis, is an emerging infectious disease transmitted by the lone
star tick, Amblyomma americanum. Tick transmission disease models for
ehrlichiosis require at least two hosts and two tick blood feeding episodes to
recapitulate the natural transmission cycle. One blood feeding is necessary for
the tick to acquire the infection from an infected host and the next feeding is
needed to transmit the bacterium to a naïve host. We have developed a model for
E. chaffeensis transmission that eliminates the entire tick acquisition stage
while still producing high numbers of infected ticks that are also able to
transmit infections to naïve hosts. Fully engorged A. americanum nymphs were
ventrally needle-infected, possibly into the midgut, and following molting, the
unfed adult ticks were used to infect naive deer and dogs. We have also
described using the ticks infected by this method the transmission of both
wild-type and transposon mutants of E. chaffeensis to its primary reservoir
host, white tailed deer and to another known host, dog. The infection
progression and IgG antibody responses in deer were similar to those observed
with transmission feeding of ticks acquiring infection by natural blood feeding.
The pathogen infections acquired by natural tick transmission and by feeding
needle-infected ticks on animals were also similar to intravenous infections in
causing persistent infections. Needle-infected ticks having the ability to
transmit pathogens will be a valuable resource to substantially simplify the
process of generating infected ticks and to study infection systems in
vertebrate hosts where interference of other pathogens could be avoided. Amblyomma americanum, also known as the lone star tick, is found in much of the
eastern United States. Since the mid-20th century, the lone star tick has been
implicated in human disease. Today, A americanum remains an important vector for
tick-borne illness. In addition to others, species of Rickettsia, Ehrlichia, and
Borrelia are all transmitted by the lone star tick. Recently described
conditions such as Southern tick-associated rash illness and anaphylaxis to red
meat following tick bites have been attributed to the lone star tick. Impressive
local reactions also can result after bites from A americanum. Early treatment
of tick-borne illness is crucial to ensure good patient outcomes. Tick-control
measures also are an important part of disease management in endemic areas. We
discuss the tick's biology, human illnesses associated with A americanum, and
methods to control tick numbers and eliminate disease in local reservoirs. |
Which is the function of ubiquilins? | Ubiquilins, a family of ubiquitin-binding proteins, are involved in all protein degradation pathways. Ubiquilin (UBQLN) proteins are adaptors thought to link ubiquitinated proteins to the proteasome. | Ubiquilins (UBQLN), a family of adaptor proteins with partial homology with
ubiquitin, are proposed to facilitate proteasomal degradation of ubiquitinated
substrates. We now demonstrate a novel role for UBQLN in promoting autophagosome
maturation during nutrient deprivation. Ectopic expression of UBQLN protects
cells against starvation-induced cell death, while depletion renders cells more
susceptible. This protective function requires the essential autophagy
regulators, Atg5 and Atg7. The ubiquitin-associated (UBA) domain of UBQLN is
required for its association with autophagosomes as well as for its prosurvival
functions.Remarkably, during starvation-induced autophagy, UBQLN promotes the
fusion of early autophagosomes with lysosomes.Overall, this work illustrates an
important function for UBQLN in cell survival during nutrient starvation, which
requires a newly recognized function for UBQLN in autophagosome maturation. Protein degradation occurs through several distinct proteolytic pathways for
membrane and cytosolic proteins. There is evidence that these processes are
linked and that crosstalk among these major protein degradation pathways occurs.
Ubiquilins, a family of ubiquitin-binding proteins, are involved in all protein
degradation pathways. This minireview provides an overview of ubiquilin function
in protein degradation and contrasts it with sequestosome-1 (p62), a protein
that also has been implicated in multiple proteolytic pathways. BACKGROUND: Ubiquilins are proteins that function as ubiquitin receptors in
eukaryotes. Mutations in two ubiquilin-encoding genes have been linked to the
genesis of neurodegenerative diseases. However, ubiquilin functions are still
poorly understood.
RESULTS: In this study, evolutionary and functional data are combined to
determine the origin and diversification of the ubiquilin gene family and to
characterize novel potential roles of ubiquilins in mammalian species, including
humans. The analysis of more than six hundred sequences allowed characterizing
ubiquilin diversity in all the main eukaryotic groups. Many organisms (e. g.
fungi, many animals) have single ubiquilin genes, but duplications in animal,
plant, alveolate and excavate species are described. Seven different ubiquilins
have been detected in vertebrates. Two of them, here called UBQLN5 and UBQLN6,
had not been hitherto described. Significantly, marsupial and eutherian mammals
have the most complex ubiquilin gene families, composed of up to 6 genes. This
exceptional mammalian-specific expansion is the result of the recent emergence
of four new genes, three of them (UBQLN3, UBQLN5 and UBQLNL) with precise
testis-specific expression patterns that indicate roles in the postmeiotic
stages of spermatogenesis. A gene with related features has independently arisen
in species of the Drosophila genus. Positive selection acting on some mammalian
ubiquilins has been detected.
CONCLUSIONS: The ubiquilin gene family is highly conserved in eukaryotes. The
infrequent lineage-specific amplifications observed may be linked to the
emergence of novel functions in particular tissues. We investigated how mitochondrial membrane proteins remain soluble in the
cytosol until their delivery to mitochondria or degradation at the proteasome.
We show that Ubiquilin family proteins bind transmembrane domains in the cytosol
to prevent aggregation and temporarily allow opportunities for membrane
targeting. Over time, Ubiquilins recruit an E3 ligase to ubiquitinate bound
clients. The attached ubiquitin engages Ubiquilin's UBA domain, normally bound
to an intramolecular UBL domain, and stabilizes the Ubiquilin-client complex.
This conformational change precludes additional chances at membrane targeting
for the client, while simultaneously freeing Ubiquilin's UBL domain for
targeting to the proteasome. Loss of Ubiquilins by genetic ablation or
sequestration in polyglutamine aggregates leads to accumulation of non-inserted
mitochondrial membrane protein precursors. These findings define Ubiquilins as a
family of chaperones for cytosolically exposed transmembrane domains and explain
how they use ubiquitin to triage clients for degradation via coordinated intra-
and intermolecular interactions. Ubiquilin (UBQLN) proteins are adaptors thought to link ubiquitinated proteins
to the proteasome. However, our lab has recently reported a previously
unappreciated role for loss of UBQLN in lung cancer progression. In fact, UBQLN
genes are lost in over 50% of lung cancer samples examined. However, a reason
for the loss of UBQLN has not been proposed, nor has a selective pressure that
could lead to deletion of UBQLN been reported. Diesel Exhaust Particles (DEP)
are a major concern in the large cities of developing nations and DEP exposed
populations are at an increased risk of developing a number of illnesses,
including lung cancer. A connection between DEP and UBQLN has never been
examined. In the present study, we determined the effect of DEP on lung cell
lines and were interested to determine if UBQLN proteins could potentially play
a protective role following treatment with DEP. Interestingly, we found that DEP
treated cells have increased expression of UBQLN proteins. In fact,
over-expression of UBQLN was capable of protecting cells from DEP toxicity. To
investigate the mechanism by which DEP leads to increased UBQLN protein levels,
we identified and interrogated microRNAs that were predicted to regulate UBQLN
mRNA. We found that DEP decreases the oncogenic microRNA, MIR155. Further, we
showed that MIR155 regulates the mRNA of UBQLN1 and UBQLN2 in cells, such that
increased MIR155 expression increased cell invasion, migration, wound formation
and clonogenicity in UBQLN-loss dependent manner. This is the first report of an
environmental carcinogen regulating expression of UBQLN proteins. We show that
exposure of cells to DEP causes an increase in UBQLN levels and that MIR155
regulates mRNA of UBQLN. Thus, we propose that DEP-induced repression of MIR155
leads to increased UBQLN levels, which in turn may be a selective pressure on
lung cells to lose UBQLN1. |
Which algorithm has been developed for prediction of protein subcellular localization using deep learning? | DeepLoc is an algorithm which has been developed for prediction of protein subcellular localization using deep learning. | MOTIVATION: The prediction of eukaryotic protein subcellular localization is a
well-studied topic in bioinformatics due to its relevance in proteomics
research. Many machine learning methods have been successfully applied in this
task, but in most of them, predictions rely on annotation of homologues from
knowledge databases. For novel proteins where no annotated homologues exist, and
for predicting the effects of sequence variants, it is desirable to have methods
for predicting protein properties from sequence information only.
RESULTS: Here, we present a prediction algorithm using deep neural networks to
predict protein subcellular localization relying only on sequence information.
At its core, the prediction model uses a recurrent neural network that processes
the entire protein sequence and an attention mechanism identifying protein
regions important for the subcellular localization. The model was trained and
tested on a protein dataset extracted from one of the latest UniProt releases,
in which experimentally annotated proteins follow more stringent criteria than
previously. We demonstrate that our model achieves a good accuracy (78% for 10
categories; 92% for membrane-bound or soluble), outperforming current
state-of-the-art algorithms, including those relying on homology information.
AVAILABILITY AND IMPLEMENTATION: The method is available as a web server at
http://www.cbs.dtu.dk/services/DeepLoc. Example code is available at
https://github.com/JJAlmagro/subcellular_localization. The dataset is available
at http://www.cbs.dtu.dk/services/DeepLoc/data.php.
CONTACT: [email protected]. |
List the continent of origin for the brown marmorated stinkbug(Halyomorpha halys) | The brown marmorated stinkbug (Halyomorpha halys) is native to Asia | The brown marmorated stink bug, Halyomorpha halys, is native to Asia (China,
Taiwan, Japan, and the Korean peninsula). It was first found in Allentown, Pa,
in 1996 and has since spread across wide areas of the Eastern United States. As
of October 2010, at least 26 states have reported the presence of the brown
marmorated stink bug. It is considered an invasive species, and to the best of
scientific knowledge, it was accidently introduced into the United States
through transportation of goods from Asia. To date, no reports of human disease
have been published in the literature. Fruit crop workers have complained of a
slight allergic reaction to the chemicals released by the bug. The brown marmorated stink bug, Halyomorpha halys, a native of Asia, has become
a serious invasive pest in the USA. H. halys was first detected in the USA in
the mid 1990s, dispersing to over 41 other states. Since 1998, H. halys has
spread throughout New Jersey, becoming an important pest of agriculture, and a
major nuisance in urban developments. In this study, we used spatial analysis,
geostatistics, and Bayesian linear regression to investigate the invasion
dynamics and colonization processes of this pest in New Jersey. We present the
results of monitoring H. halys from 51 to 71 black light traps that were placed
on farms throughout New Jersey from 2004 to 2011 and examined relationships
between total yearly densities of H. halys and square hectares of 48
landscape/land use variables derived from urban, wetland, forest, and
agriculture metadata, as well as distances to nearest highways. From these
analyses we propose the following hypotheses: (1) H. halys density is strongly
associated with urban developments and railroads during its initial
establishment and dispersal from 2004 to 2006; (2) H. halys overwintering in
multiple habitats and feeding on a variety of plants may have reduced the Allee
effect, thus facilitating movement into the southernmost regions of the state by
railroads from 2005 to 2008; (3) density of H. halys contracted in 2009 possibly
from invading wetlands or sampling artifact; (4) subsequent invasion of H. halys
from the northwest to the south in 2010 may conform to a stratified-dispersal
model marked by rapid long-distance movement, from railroads and wetland
rights-of-way; and (5) high densities of H. halys may be associated with
agriculture in southern New Jersey in 2011. These landscape features associated
with the invasion of H. halys in New Jersey may predict its potential rate of
invasion across the USA and worldwide. Brown marmorated stink bug, Halyomorpha halys (Stål), (Hemiptera: Pentatomidae)
is an invasive polyphagous agricultural and urban nuisance pest of Asian origin
that is becoming widespread in North America and Europe. Despite the economic
importance of pentatomid pests worldwide, their feeding behavior is poorly
understood. Electronically monitored insect feeding (EMIF) technology is a
useful tool in studies of feeding behavior of Hemiptera. Here we examined H.
halys feeding behavior using an EMIF system designed for high throughput studies
in environmental chambers. Our objectives were to quantify feeding activity by
monitoring proboscis contacts with green beans, including labial dabbing and
stylet penetration of the beans, which we collectively define as 'probes'. We
examined frequency and duration of 'probes' in field-collected H. halys over 48
hours and we determined how environmental conditions could affect diel and
seasonal periodicity of 'probing' activity. We found differences in 'probing'
activity between months when the assays were conducted. These differences in
activity may have reflected different environmental conditions, and they also
coincide with what is known about the phenology of H. halys. While a substantial
number of 'probes' occurred during scotophase, including some of the longest
mean 'probe' durations, activity was either lower or similar to 'probing'
activity levels during photophase on average. We found that temperature had a
significant impact on H. halys 'probing' behavior and may influence periodicity
of activity. Our data suggest that the minimal temperature at which 'probing' of
H. halys occurs is between 3.5 and 6.1 °C (95% CI), and that 'probing' does not
occur at temperatures above 26.5 to 29.6 °C (95% CI). We estimated that the
optimal temperature for 'probing' is between 16 and 17 °C. The brown marmorated stink bug, Halyomorpha halys (Stål), is native to eastern
Asia and is presently invading North America. Little is known about the exposure
to and effects of winter temperatures in newly invaded regions on H. halys The
overwintering habitats that this species utilizes vary greatly in their thermal
buffering capacity. They naturally overwinter in aggregations beneath loose bark
on trees and in cliff outcroppings, but will also commonly aggregate in
buildings. Effects of cold temperatures such as mortality and freezing have yet
to be quantified in the invading population. We report that H. halys is chill
intolerant (i.e., dies before reaching its freezing point), and that the degree
of cold tolerance of populations in North America differs by season, sex, and
acclimation location. The mean winter supercooling point (± SEM) of individuals
acclimated in Minnesota was -17.06 °C ± 0.13 and in Virginia was -13.90 °C ±
0.09. By using laboratory assays of lower lethal temperatures and ambient air
temperature records, we accurately forecasted mortality for field experiments in
Minnesota and Virginia. Temperature refugia provided by human-built structures
are likely crucial for overwintering survival during atypically cold winters and
possibly contribute to the northern geographic range expansion of this
economically damaging insect in the temperate climates of North America. With the introduction and establishment of exotic species, most ecosystems now
contain both native and exotic plants and herbivores. Recent research identifies
several factors that govern how specialist herbivores switch host plants upon
introduction. Predicting the feeding ecology and impacts of introduced
generalist species, however, remains difficult. Here, we examine how plant
geographic origin, an indicator of shared co-evolutionary history, influences
patterns of host use by a generalist, invasive herbivore, while accounting for
variation in plant availability. The brown marmorated stink bug, Halyomorpha
halys, is a highly polyphagous Asian herbivore and an economically important
invasive pest in North America and Europe. In visual surveys of 220 plant taxa
in commercial nurseries in Maryland, USA, H. halys was more abundant on
non-Asian plants and selected these over Asian plants. The relationship between
the relative use of plants and their availability was strongly positive but
depended also on plant origin at two of our three sites, where the higher
relative use of non-Asian plants was greatest for highly abundant taxa. These
results highlight the importance of considering both plant origin and relative
abundance in understanding the selection of host plants by invasive generalist
herbivores in diverse, natural and urban forests. Human mediated transportation into novel habitats is a prerequisite for the
establishment of non-native species that become invasive, so knowledge of common
sources may allow prevention. The brown marmorated stink bug (BMSB, Halyomorpha
halys) is an East Asian species now established across North America and Europe,
that in the Eastern United States of America (US) and Italy is causing
significant economic losses to agriculture. After US populations were shown to
originate from Northern China, others have tried to source BMSB populations now
in Canada, Switzerland, Italy, France, Greece, and Hungary. Due to selection of
different molecular markers, however, integrating all the datasets to obtain a
broader picture of BMSB's expansion has been difficult. To address this
limitation we focused on a single locus, the barcode region in the cytochrome
oxidase I mitochondrial gene, and analyzed representative BMSB samples from
across its current global range using an Approximate Bayesian Computation
approach. We found that China is the likely source of most non-native
populations, with at least four separate introductions in North America and
three in Europe. Additionally, we found evidence of one bridgehead event: a
likely Eastern US source for the central Italy populations that interestingly
share enhanced pest status. In the United States, California (CA) is the primary commercial producer of
pistachio nuts, Pistacia vera L. (Anacardiaceae). The brown marmorated stink bug
(BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an invasive and
polyphagous insect pest from Asia, has established in urban areas in several
pistachio-growing counties in CA. Breeding BMSB populations have not been
detected in commercial pistachio acreage. However, the detection of BMSB in Kern
and Fresno counties, major Kerman pistachio producing areas in CA, underscored
key knowledge gaps on BMSB ecology in CA and motivated investigations on the
susceptibility of pistachio nuts to BMSB feeding. Laboratory feeding trials
conducted in quarantine under permit indicated that adult BMSB stylets can
penetrate developing pistachio shells and associated feeding was correlated with
kernel necrosis for nuts collected mid to late season (June to August 2016).
Feeding damage estimates indicated that higher levels of kernel injury were
associated with female BMSB when compared to feeding by male BMSB. These results
suggest that there is probable risk of feeding damage to field grown pistachios
from BMSB. The implications of this study for BMSB pest management in the CA
pistachio system and future research directions are discussed. |
Please list 6 symptoms of Scarlet fever. | Symptoms of scarlet fever include fever, rash, strawberry tongue and sore throat. In some cases other symptoms, angular stomatitis, tonsular exudate, and swollen lymph nodes are seen. | Group A streptococcal strains were isolated from the throats of 46 children
suffering from scarlet fever. For detection of erythrogenic toxins (ETs), the
culture supernatants were concentrated 100 times by ethanol precipitation and
solubilisation in acetate buffer. ELISA was used to identify ETA and double
immunodiffusion to identify ETB and ETC. The presence of the ETA gene was
detected by a specific DNA probe. ETA (alone or in combination with ETB and/or
ETC) was found in 51.9% of the strains, ETB (alone or in combination with ETA
and/or ETC) in 76.9% and ETC (in combination with ETA and ETB) in 28.9%. Only
5.8% of strains did not produce any detectable ET. In SDS-PAGE, supernatants of
ETB-producing strains showed a pronounced band in either the region of the
proteinase zymogen or the active proteinase. There was no correlation between
the type of erythrogenic toxin and the serological M or T type of the producing
strain. The mitogenic potency of culture supernatants did not differ
significantly irrespective of the toxin type(s) present. Culture supernatants of
strains without a detectable amount of the known ETs were highly mitogenic,
indicating the production of other streptococcal mitogens. A correlation with
clinical symptoms was determined with regard to exanthema and fever. Strains
producing two or three toxins caused a more intense exanthema. Patient
temperature was higher (greater than or equal to 38 degrees C) when the
infecting strain produced ETB. The toxin-producing patterns of the strains of
this study were compared with those isolated during the last epidemic outbreak
of scarlet fever in East Germany. 11,119 patients with scarlet fever admitted in the last sixteen years, from 1973
to 1988, to Sapporo City General Hospital, were studied statistically on
symptoms and laboratory findings. The results were summarized as follows: 1.
Annual number of patients have reduced suddenly since 1981, and become zero in
1989. The patients increased in number during the winter season. Eighty two
percent of the cases were between 3 and 8 years of age, and the average age was
5.8 year-old. 2. Cases of above-38 degrees C temperature were seen in about
81.4%, and from 2 to 5 days-duration of temperature were seen in 86.6% of the
patients in the year 1976. Cases of above-moderate rash were observed in 68.2%,
sever redness of throat in 29.9%, strawberry tongue in 86.3% and angular
stomatitis in 37.7% of the patients. In recent statistical analysis (1982-1988),
we found, however, a tendency that patients having stronger symptoms were being
introduced to our hospital. 3. The higher rates of cases showing elevated ASD
titer were seen in the elder patients and in the winter. C-reactive protein
(CRP) titers were mostly in the range of (-) to (greater than or equal to 6+),
having 2.4 + on an average. 4. Patients who developed into overt nephritis were
not seen. Cases of microscopic hematuria (greater than or equal to 3 red cells/f
in urine sediments), however, were observed in 1.1% (125/11,119). Sever
complications were hardly seen. 5. Reappearance of beta-hemolytic streptococci
(on a week after discharge) were found in 3.1% (241/7,877). 6. Reinfection or
relapse cases of scarlet fever were found in 6.7% (642/9,585).(ABSTRACT
TRUNCATED AT 250 WORDS) 82 cases of streptococcal infection (SI) in children who died in 1977-1985 are
studied. Higher incidence of SI in children particularly in those who died at
home is emphasized. As a rule, the proper diagnosis was not established
clinically. By manifestations the observations were divided into two groups: 1)
SI with a pronounced generalization including a pharyngeal one (31 cases), 4 of
them with a rash (scarlet fever); extrapharyngeal (7 cases), 6 of them with a
rash (scarlet fever); 2) SI without pronounced generalization (localized)
including 33 cases with the involvement of the lungs and tonsilla and having an
ordinary course and 11 cases of a sudden death. SI structural manifestations
involved development of necrotic or purulent-necrotic inflammation of a various
degree in the area of the primary focus, regional lymph nodes as well as in the
foci resulting from lymphohaematogenic and intracanalicular dissemination. The
first symptoms of the septic process could be found even in case of death during
the first day of the disease. The role of viral respiratory infection being the
background for the SI development, especially for its pharyngeal variant and
lung affection, is shown. The significance of thymomegaly and adrenal hypoplasia
in the development of a sudden death is revealed. Scarlet fever consists in a diffuse exanthem associated with mucous changes.
Classical scarlet fever is rare now, but other severe streptococcal infections
have become more frequent, such as streptococcal toxic shock syndrome. The
scarlatiniform exanthem and the shock observed in this disease are due to a
streptococcal pyrogenic exotoxin. Exfoliative toxins secreted by Staphylococcus
aureus are responsible for the tender erythema and cutaneous scaling
characteristic of staphylococcal scalded skin syndrome of infancy. The so-called
staphylococcal scarlet fever is probably an attenuated variant of this disease.
Toxic shock syndrome toxin 1 (TSST1) is another staphylococcal toxin implied in
the staphylococcal toxic shock syndrome. This disease is characterized by
general symptoms and a scarlatiniform exanthem which are due to the effects of
TSST1, acting as a superantigen. Because childhood rashes may be difficult to differentiate by appearance alone,
it is important to consider the entire clinical presentation to help make the
appropriate diagnosis. Considerations include the appearance and location of the
rash; the clinical course; and associated symptoms, such as pruritus or fever. A
fever is likely to occur with roseola, erythema infectiosum (fifth disease), and
scarlet fever. Pruritus sometimes occurs with atopic dermatitis, pityriasis
rosea, erythema infectiosum, molluscum contagiosum, and tinea infection. The key
feature of roseola is a rash presenting after resolution of a high fever,
whereas the distinguishing features in pityriasis rosea are a herald patch and a
bilateral and symmetric rash in a Christmas tree pattern. The rash associated
with scarlet fever usually develops on the upper trunk, then spreads throughout
the body, sparing the palms and soles. Impetigo is a superficial bacterial
infection that most commonly affects the face and extremities of children.
Erythema infectiosum is characterized by a viral prodrome followed by the
"slapped cheek" facial rash. Flesh-colored or pearly white papules with central
umbilication occur with molluscum contagiosum, a highly contagious viral
infection that usually resolves without intervention. Tinea is a common fungal
skin infection in children that affects the scalp, body, groin, feet, hands, or
nails. Atopic dermatitis is a chronic, relapsing inflammatory skin condition
that may present with a variety of skin changes. |
Gallbladder carriage is a well recognised means of spread of which bacteria? | Gallbladder carriage is associated with spread of Salmonella Typhi. | Although typhoid fever has been intensively studied, chronic typhoid carriage
still represents a problem for the transmission and persistence of the disease
in areas of endemicity. This chronic state is highly associated with the
presence of gallstones in the gallbladder of infected carriers upon which
Salmonella can form robust biofilms. However, we hypothesize that in addition to
gallstones, the gallbladder epithelium aids in the establishment/maintece of
chronic carriage. In this work, we present evidence of the role of the
gallbladder epithelium in chronic carriage by a mechanism involving invasion,
intracellular persistence, and biofilm formation. Salmonella was able to adhere
to and invade polarized gallbladder epithelial cells apically in the absence and
presence of bile in a Salmonella pathogenicity island 1 (SPI-1)-dependent
manner. Intracellular replication of Salmonella was also evident at 12 and 24 h
postinvasion. A flowthrough system revealed that Salmonella is able to adhere to
and form extensive bacterial foci on gallbladder epithelial cells as early as 12
h postinoculation. In vivo experiments using a chronic mouse model of typhoid
carriage showed invasion and damage of the gallbladder epithelium and lamina
propria up to 2 months after Salmonella infection, with an abundant presence of
macrophages, a relative absence of neutrophils, and extrusion of infected
epithelial cells. Additionally, microcolonies of Salmonella cells were evident
on the surface of the mouse gallbladder epithelia up to 21 days postinfection.
These data reveal a second potential mechanism, intracellular persistence and/or
bacterial aggregation in/on the gallbladder epithelium with luminal cell
extrusion, for Salmonella maintece in the gallbladder. Author information:
(1)Department of Microbial Infection and Immunity, Center for Microbial
Interface Biology, The Ohio State University, OH, USA. Electronic address:
[email protected].
(2)Department of Microbial Infection and Immunity, Center for Microbial
Interface Biology, The Ohio State University, OH, USA.
(3)The Hospital for Tropical Diseases, Wellcome Trust Major Overseas Programme,
Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam; Centre for
Tropical Medicine, Oxford University, Oxford, United Kingdom; The London School
of Hygiene and Tropical Medicine, London, United Kingdom.
(4)Oxford University Clinical Research Unit, Patan Academy of Health Sciences,
Kathmandu, Nepal.
(5)Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA,
USA; Department of Medicine, Harvard Medical School, Boston, MA, USA.
(6)Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA,
USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Department
of Immunology and Infectious Diseases, Harvard School of Public Health, Boston,
MA, USA. The host-pathogen interactions occurring in the gallbladder during Salmonella
Typhi colonization contribute to typhoid fever pathogenesis during the acute and
chronic stages of disease. The gallbladder is the primary reservoir during
chronic typhoid carriage. In this organ, Salmonella encounters host-barriers
including bile, immunoglobulins, and mucus. However, the bacterium possesses
mechanisms to resist and persist in this environment, in part by its ability to
attach to and invade into the gallbladder epithelium. Such persistence in the
gallbladder epithelium contributes to chronic carriage. In addition, patients
harboring gallstones in their gallbladders have increased risk of becoming
carriers because these abnormalities serve as a substrate for Salmonella biofilm
formation. Our laboratory has studied the Salmonella interactions in this
specific environment by developing in vitro methods that closely mimic the
gallbladder and gallstones niches. These methods are reproducible and provide a
platform for future studies of acute and chronic bacterial infections in the
gallbladder. Salmonella enterica serovar Typhi, the causative agent of typhoid fever in
humans, forms biofilms encapsulated by an extracellular matrix (ECM). Biofilms
facilitate colonization and persistent infection in gallbladders of humans and
mouse models of chronic carriage. Individual roles of matrix components have not
been completely elucidated in vitro or in vivo To examine individual functions,
strains of Salmonella enterica serovar Typhimurium, the murine model of S Typhi,
in which various ECM genes were deleted or added, were created to examine
biofilm formation, colonization, and persistence in the gallbladder. Studies
show that curli contributes most significantly to biofilm formation. Expression
of Vi antigen decreased biofilm formation in vitro and virulence and bacterial
survival in vivo without altering the examined gallbladder pro- or
anti-inflammatory cytokines. Oppositely, loss of all ECM components (ΔwcaM ΔcsgA
ΔyihO ΔbcsE) increased virulence and bacterial survival in vivo and reduced
gallbladder interleukin-10 (IL-10) levels. Colanic acid and curli mutants had
the largest defects in biofilm-forming ability and contributed most
significantly to the virulence increase of the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant
strain. While the ΔwcaM ΔcsgA ΔyihO ΔbcsE mutant was not altered in resistance
to complement or growth in macrophages, it attached and invaded macrophages
better than the wild-type (WT) strain. These data suggest that ECM components
have various levels of importance in biofilm formation and gallbladder
colonization and that the ECM diminishes disseminated disease in our model,
perhaps by reducing cell attachment/invasion and dampening inflammation by
maintaining/inducing IL-10 production. Understanding how ECM components aid
acute disease and persistence could lead to improvements in therapeutic
treatment of typhoid fever patients. |
What is included in the Mentzer index? | Mentzer index (MCV/RBC) is mean corpuscular volume (MCV) and red blood cell count (RBC) ratio. It is used for differentiation of thalassemia and iron deficiency anemia. | Several laboratory tests have been proposed for the differentiation of beta
thalassemia from iron deficiency, including decision functions based on red
blood cells indices generated by electronic cell counters. The accuracy of these
screening methods was assessed in 192 patients with microcytosis known to be
secondary to beta thalassemia minor and 72 patients with iron deficiency. The
functions evaluated were: 1) discrimit function of England an Fraser:
MCV--(5xHb)--RBC--8.4; 2) ratio of MCH/RBC; 3) ratio of MCV/RBC; 4) ratio of
(MCV)2 x MCH and 5) the erythrocyte count. The discrimit function of England
and Fraser showed the highs, percentage of correct distinction between iron
deficiency and beta thalassemia minor, although diagnosis errors occurred in
10%. Mentzer ratio MCV/RBC detected all cases of beta thalassemia but was a poor
index for iron deficiency detection. The tested discrimit function, with
exception of the Mentzer ratio, although not sufficiently accurate for
definitive diagnosis, appears to be a useful technique in the initial screening
of patients with microcytosis. |
Which disease is treated with Fexinidazole? | Oral fexinidazole is effective for late-stage human african trypanosomiasis. | Fexinidazole is a 5-nitroimidazole drug currently in clinical development for
the treatment of human sleeping sickness (human African trypanosomiasis [HAT]),
caused by infection with species of the protozoan parasite Trypanosoma brucei.
The compound and its two principal metabolites, sulfoxide and sulfone, have been
assessed for their ability to kill a range of T. brucei parasite strains in
vitro and to cure both acute and chronic HAT disease models in the mouse. The
parent molecule and both metabolites have shown trypanocidal activity in vitro
in the 0.7-to-3.3 μM (0.2-to-0.9 μg/ml) range against all parasite strains
tested. In vivo, fexinidazole is orally effective in curing both acute and
chronic diseases in the mouse at doses of 100 mg/kg of body weight/day for 4
days and 200 mg/kg/day for 5 days, respectively. Pharmacokinetic data indicate
that it is likely that the sulfoxide and sulfone metabolites provide most, if
not all, of the in vivo killing activity. Fexinidazole and its metabolites
require up to 48 h exposure in order to induce maximal trypanocidal efficacy in
vitro. The parent drug and its metabolites show no in vitro cross-reactivity in
terms of trypanocidal activity with either themselves or other known
trypanocidal drugs in use in humans. The in vitro and in vivo antitrypanosomal
activities of fexinidazole and its two principal metabolites provide evidence
that the compound has the potential to be an effective oral treatment for both
the T. b. gambiense and T. b. rhodesiense forms of human sleeping sickness and
both stages of the disease. Safer and more effective oral drugs are required to treat visceral
leishmaniasis, a parasitic disease that kills 50,000 to 60,000 people each year
in parts of Asia, Africa, and Latin America. Here, we report that fexinidazole,
a drug currently in phase 1 clinical trials for treating African
trypanosomiasis, shows promise for treating visceral leishmaniasis. This
2-substituted 5-nitroimidazole drug is rapidly oxidized in vivo in mice, dogs,
and humans to sulfoxide and sulfone metabolites. Both metabolites of
fexinidazole were active against Leishmania donovani amastigotes grown in
macrophages, whereas the parent compound was inactive. Pharmacokinetic studies
with fexinidazole (200 mg/kg) showed that fexinidazole sulfone achieves blood
concentrations in mice above the EC(99) (effective concentration inhibiting
growth by 99%) value for at least 24 hours after a single oral dose. A
once-daily regimen for 5 days at this dose resulted in a 98.4% suppression of
infection in a mouse model of visceral leishmaniasis, equivalent to that seen
with the drugs miltefosine and Pentostam, which are currently used clinically to
treat this tropical disease. In African trypanosomes, the mode of action of
nitro drugs involves reductive activation via a NADH (reduced form of
nicotinamide adenine dinucleotide)-dependent bacterial-like nitroreductase.
Overexpression of the leishmanial homolog of this nitroreductase in L. donovani
increased sensitivity to fexinidazole by 19-fold, indicating that a similar
mechanism is involved in both parasites. These findings illustrate the potential
of fexinidazole as an oral drug therapy for treating visceral leishmaniasis. BACKGROUND: New safe and effective treatments for Chagas disease (CD) are
urgently needed. Current chemotherapy options for CD have significant
limitations, including failure to uniformly achieve parasitological cure or
prevent the chronic phase of CD, and safety and tolerability concerns.
Fexinidazole, a 2-subsituted 5-nitroimidazole drug candidate rediscovered
following extensive compound mining by the Drugs for Neglected Diseases
initiative and currently in Phase I clinical study for the treatment of human
African trypanosomiasis, was evaluated in experimental models of acute and
chronic CD caused by different strains of Trypanosoma cruzi.
METHODS AND FINDINGS: We investigated the in vivo activity of fexinidazole
against T. cruzi, using mice as hosts. The T. cruzi strains used in the study
were previously characterized in murine models as susceptible (CL strain),
partially resistant (Y strain), and resistant (Colombian and VL-10 strains) to
the drugs currently in clinical use, benznidazole and nifurtimox. Our results
demonstrated that fexinidazole was effective in suppressing parasitemia and
preventing death in infected animals for all strains tested. In addition,
assessment of definitive parasite clearance (cure) through parasitological, PCR,
and serological methods showed cure rates of 80.0% against CL and Y strains,
88.9% against VL-10 strain, and 77.8% against Colombian strain among animals
treated during acute phase, and 70% (VL-10 strain) in those treated in chronic
phase. Benznidazole had a similar effect against susceptible and partially
resistant T. cruzi strains. Fexinidazole treatment was also shown to reduce
myocarditis in all animals infected with VL-10 or Colombian resistant T. cruzi
strains, although parasite eradication was not achieved in all treated animals
at the tested doses.
CONCLUSIONS: Fexinidazole is an effective oral treatment of acute and chronic
experimental CD caused by benznidazole-susceptible, partially resistant, and
resistant T. cruzi. These findings illustrate the potential of fexinidazole as a
drug candidate for the treatment of human CD. BACKGROUND AND OBJECTIVES: Fexinidazole is a 5-nitroimidazole recently included
in a clinical efficacy trial as an oral drug for the treatment of human African
trypanosomiasis (HAT). Preclinical studies showed it acts as a pharmacologically
active pro-drug with two key active metabolites: sulfoxide and sulfone (the most
active metabolite). The present studies aimed to determine the best dose regimen
for the treatment of stage 2 sleeping sickness patients, which could eventually
also treat stage 1 patients.
METHODS: Fexinidazole was assessed in 154 healthy adult male subjects of
sub-Saharan African origin. Three initial first-in-human studies and two
additional studies assessed a single ascending dose and multiple ascending doses
(both under fasted conditions), tablet versus suspension formulation and food
effect (fasted vs. high-fat meal and field-adapted food), and multiple ascending
doses with a loading dose regimen under fed conditions.
RESULTS: Fexinidazole was well-tolerated in a single dose from 100 to 3,600 mg,
with quick absorption of the parent drug and rapid metabolism into sulfoxide
[time to maximum concentration (t max) 2-5 h] and sulfone (t max 18-24 h). The
tablet formulation was approximately 25 % less bioavailable than the suspension,
and food intake increased drug absorption and plasma concentrations of
fexinidazole and its two metabolites by approximately 200 %. Fourteen-day
multiple ascending dosing administered up to 3,600 mg/day in fasted conditions
showed that fexinidazole was generally well-tolerated (mild to moderate,
spontaneously reversible drug-related adverse events). Following the high-fat
food effect finding, another study was conducted to evaluate the impact of a
low-fat regimen closer to that of the target population, showing that the type
of meal does not influence fexinidazole absorption. The last study showed that a
loading dose of 1,800 mg/day for 4 days followed by a 1,200 mg/day regimen for 6
days with a normal meal provided the desired exposure of fexinidazole and its
metabolites, particularly sulfone, with good tolerability. Based on preclinical
evidence from a chronic infection mouse model, systemic drug concentrations
obtained are expected to be clinically effective in stage 2 HAT.
CONCLUSIONS: These studies show that fexinidazole can be safely assessed in
patients as a potential oral cure for both stages of HAT. This study was designed to verify the in vivo efficacy of sulfoxide and sulfone
fexinidazole metabolites following oral administration in a murine model of
Chagas disease. Female Swiss mice infected with the Y strain of Trypanosoma
cruzi were treated orally once per day with each metabolite at doses of 10 to
100 mg/kg of body weight for a period of 20 days. Parasitemia was monitored
throughout, and cures were detected by parasitological and PCR assays. The
results were compared with those achieved with benznidazole treatment at the
same doses. Fexinidazole metabolites were effective in reducing the numbers of
circulating parasites and protecting mice against death, compared with untreated
mice, but without providing cures at daily doses of 10 and 25 mg/kg. Both
metabolites were effective in curing mice at 50 mg/kg/day (30% to 40%) and 100
mg/kg/day (100%). In the benznidazole-treated group, parasitological cure was
detected only in animals treated with the higher dose of 100 mg/kg/day (80%).
Single-dose pharmacokinetic parameters for each metabolite were obtained from a
parallel group of uninfected mice and were used to estimate the profiles
following repeated doses. Pharmacokinetic data suggested that biological
efficacy most likely resides with the sulfone metabolite (or subsequent reactive
metabolites formed following reduction of the nitro group) following
administration of either the sulfoxide or the sulfone and that prolonged plasma
exposure over the 24-h dosing window is required to achieve high cure rates.
Fexinidazole metabolites were effective in treating T. cruzi in a mouse model of
acute infection, with cure rates superior to those achieved with either
fexinidazole itself or benznidazole. OBJECTIVES: To review current and emerging tools for Gambiense HAT control and
elimination, and propose strategies that integrate these tools with
epidemiological evidence.
METHODS: We reviewed the scientific literature to identify contemporary and
emerging tools and strategies for controlling and eliminating Gambiense HAT.
Through an iterative process involving key stakeholders, we then developed
comprehensive scenarios leading to elimination, considering both established and
new tools for diagnosis, case treatment and vector control.
RESULTS: Core components of all scenarios include detecting and treating cases
with established or emerging techniques. Relatively more intensive scenarios
incorporate vector control. New tools considered include tiny targets for tsetse
fly control, use of rapid diagnostic tests and oral treatment with fexinidazole
or oxaboroles. Scenarios consider the time when critical new tools are expected
to become ready for deployment by national control programmes. Based on a review
of the latest epidemiological data, we estimate the various interventions to
cover 1,380,600 km(2) and 56,986,000 people.
CONCLUSIONS: A number of new tools will fill critical gaps in the current
armamentarium for diagnosing and treating Gambiense HAT. Deploying these tools
in endemic areas will facilitate the comprehensive and sustainable control of
the disease considerably and contribute to the ultimate goal of elimination. AIM: Fexinidazole (FEX) is a nitroimidazole being developed as a new trypanocide
treatment for human African trypanosomiasis/sleeping sickness. Its main
metabolites, fexinidazole sulfoxide (M1) and fexinidazole sulfone (M2), show the
same in vitro pharmacological activity as FEX.
METHODS & RESULTS: An LC-MS/MS assay was developed for quantitation of FEX in
DBS, collected via finger-prick from healthy subjects. The DBS assay was
specific, accurate and reproducible for FEX, M1 and M2 when validated against
the current plasma assay. DBS samples were stable for 24 h at 37°C with 95%
relative humidity, and 58 weeks desiccated at room temperature.
CONCLUSION: DBS finger-prick sampling offers a simple, practical method for
determining FEX, M1 and M2 concentrations in clinical studies in Africa. BACKGROUND: Few therapeutic options are available to treat the late-stage of
human African trypanosomiasis, a neglected tropical disease, caused by
Trypanosoma brucei gambiense (g-HAT). The firstline treatment is a combination
therapy of oral nifurtimox and intravenous eflornithine that needs to be
administered in a hospital setting by trained personnel, which is not optimal
given that patients often live in remote areas with few health resources.
Therefore, we aimed to assess the safety and efficacy of an oral regimen of
fexinidazole (a 2-substituted 5-nitroimidazole with proven trypanocidal
activity) versus nifurtimox eflornithine combination therapy in patients with
late-stage g-HAT.
METHODS: In this randomised, phase 2/3, open-label, non-inferiority trial, we
recruited patients aged 15 years and older with late-stage g-HAT from g-HAT
treatment centres in the Democratic Republic of the Congo (n=9) and the Central
African Republic (n=1). Patients were randomly assigned (2:1) to receive either
fexinidazole or nifurtimox eflornithine combination therapy according to a
predefined randomisation list (block size six). The funder, data management
personnel, and study statisticians were masked to treatment. Oral fexinidazole
was given once a day (days 1-4: 1800 mg, days 5-10: 1200 mg). Oral nifurtimox
was given three times a day (days 1-10: 15 mg/kg per day) with eflornithine
twice a day as 2 h infusions (days 1-7: 400 mg/kg per day). The primary endpoint
was success at 18 months (ie, deemed as patients being alive, having no evidence
of trypanosomes in any body fluid, not requiring rescue medication, and having a
cerebrospinal fluid white blood cell count ≤20 cells per μL). Safety was
assessed through routine monitoring. Primary efficacy analysis was done in the
modified intention-to-treat population and safety analyses in the
intention-to-treat population. The acceptable margin for the difference in
success rates was defined as 13%. This study has been completed and is
registered with ClinicalTrials.gov, number NCT01685827.
FINDINGS: Between October, 2012, and November, 2016, 419 patients were
pre-screened. Of the 409 eligible patients, 14 were not included because they
did not meet all inclusion criteria (n=12) or for another reason (n=2).
Therefore, 394 patients were randomly assigned, 264 to receive fexinidazole and
130 to receive nifurtimox eflornithine combination therapy. Success at 18 months
was recorded in 239 (91%) patients given fexinidazole and 124 (98%) patients
given nifurtimox eflornithine combination therapy, within the margin of
acceptable difference of -6·4% (97·06% CI -11·2 to -1·6; p=0·0029). We noted no
difference in the proportion of patients who experienced treatment-related
adverse events (215 [81%] in the fexinidazole group vs 102 [79%] in the
nifurtimox eflornithine combination therapy group). Treatment discontinuations
were unrelated to treatment (n=2 [1%] in the fexinidazole group). Temporary
nifurtimox eflornithine combination therapy interruption occurred in three (2%)
patients. 11 patients died during the study (nine [3%] in the fexinidazole group
vs two [2%] in the nifurtimox eflornithine combination therapy group).
INTERPRETATION: Our findings show that oral fexinidazole is effective and safe
for the treatment of T b gambiense infection compared with nifurtimox
eflornithine combination therapy in late-stage HAT patients. Fexinidazole could
be a key asset in the elimination of this fatal neglected disease.
FUNDING: Drugs for Neglected Diseases initiative. |
Is Tocilizumab effective for Giant-Cell Arteritis? | Yes, Tocilizumab effective for Giant-Cell Arteritis. Its efficacy was proven in clinical trials. Tocilizumab may exert its therapeutic effects in Giant-Cell Arteritis by increasing the proliferation and activation of Tregs, and by reverting the pathogenic Treg phenotype seen during active disease. | INTRODUCTION: Treatment of giant cell arteritis is based on prolonged
corticosteroid therapy but adverse side effects are common especially in the
elderly.
CASE REPORTS: We report three patients with giant cell vasculitis treated by
tocilizumab, an interleukin-6 receptor antibody, owing to resistance or
intolerance to corticosteroid therapy. A favorable outcome was rapidly observed
both on clinical and biological data allowing a corticoid therapy sparing.
CONCLUSION: Tocilizumab is a promising treatment of giant cell arteritis but
controlled trials are needed to confirm its efficacy. OBJECTIVES: Patients with giant cell arteritis (GCA) often respond to
corticosteroid (CS) therapy; however, the majority of patients relapse when CS
therapy is tapered or withdrawn. The purpose of this study was to assess the
efficacy of tocilizumab (TCZ) in patients with relapsing GCA.
METHODS: Four patients with relapsing GCA received TCZ monthly (4mg/kg or
8mg/kg). Disease activity and drug tolerability were evaluated clinically and
via laboratory test results at the beginning of the study and every 3 months
until the publication of this study. All four patients were still receiving TCZ
monthly at the time of manuscript submission.
RESULTS: All four patients treated with TCZ achieved clinical and laboratory
response. No adverse events were detected.
CONCLUSIONS: In our small case series, TCZ was efficacious and well tolerated in
patients with relapsing GCA. Proper randomised controlled trials are required to
achieve confident conclusions regarding the safety and efficacy of TCZ in GCA. PURPOSE OF REVIEW: This article critically reviews the advances in medical
management of giant cell arteritis (GCA) and Takayasu arteritis (TAK) with a
focus on recent developments in targeted biologic therapy.
RECENT FINDINGS: The role of biologics in the treatment of large vessel
vasculitis (LVV) is expanding. TNFα inhibitors appear to be effective in the
treatment of TAK but have little benefit in GCA. Preliminary clinical trial data
suggest that abatacept and tocilizumab reduce the risk of relapse in GCA.
Increasing observational evidence supports the use of interleukin-6 inhibitors
in TAK. Based on a small open-label study, ustekinumab appears safe and
potentially effective for refractory GCA. A possible role of B cell
dysregulation may contribute to pathogenic mechanisms in LVV, but support for
the use of B cell depleting therapy is limited.
SUMMARY: Interleukin-6 inhibitors appear efficacious in the treatment of
refractory cases of LVV; however, utility in newly diagnosed
immunosuppressive-naïve patients is less well established. Abatacept and
ustekinumab are promising targets for therapy in LVV but further investigation
is needed before routine use is considered. Author information:
(1)From the Université Paris-Descartes; APHP, Hôpital Cochin, Centre de
référence maladies auto-immunes et systémiques rares, service de médecine
interne, Paris; Service de médecine interne, Centre hospitalier d'Abbeville,
Abbeville; Service de médecine interne, Université Grenoble Alpes, Centre
Hospitalier Universitaire (CHU) de Grenoble, Grenoble; Service de médecine
interne, Centre Hospitalier Général de Mulhouse, Mulhouse; Service de médecine
interne, CHU de Limoges, Limoges; Department of Rheumatology, Hôpital Cochin,
APHP; INSERM (U1153): Clinical epidemiology and biostatistics, PRES Sorbonne
Paris-Cité, Paris; Service de médecine interne, Hôpital Avicenne, Bobigny;
Service de médecine interne, Hôpital Hôtel-Dieu, Nantes; Service de
rhumatologie, CHU de Clermont-Ferrand, Clermont Ferrand; Service de médecine
interne et médecine polyvalente, Hôpital de Saint Quentin, Saint Quentin;
Service de médecine interne, CH de Dax, Dax; Service de médecine interne,
Hôpital Claude Huriez, Lille; Centre d'Investigation Clinique Biothérapie INSERM
CIC-1431, FHU INCREASE, Service de rhumatologie, Centre Hospitalier Régional
Universitaire (CHRU), Besançon, France.A. Régent, MD, PhD, Université
Paris-Descartes; APHP, Hôpital Cochin, Centre de référence maladies auto-immunes
et systémiques rares, service de médecine interne; S. Redeker, MD, Service de
médecine interne, Centre hospitalier d'Abbeville; A. Deroux, MD, Service de
médecine interne, Université Grenoble Alpes, CHU de Grenoble; P. Kieffer, MD,
Service de médecine interne, Centre Hospitalier Général de Mulhouse; K.H. Ly,
MD, PhD, Service de médecine interne, CHU de Limoges; M. Dougados, MD, PhD,
Université Paris-Descartes, Department of Rheumatology, APHP, Hôpital Cochin,
INSERM (U1153): Clinical Epidemiology and Biostatistics, PRES Sorbonne
Paris-Cité; E. Liozon, MD, Service de médecine interne, CHU de Limoges; C.
Larroche, MD, Service de médecine interne, Hôpital Avicenne; Giant-cell arteritis (GCA) is the most common vasculitis in people aged more
than 50 years. Despite the frequency of this disease, there is currently no
international consensus on its therapeutic modalities. The aim of this study was
to conduct a review on an international literature about the treatment of GCA,
whatever the clinical pattern might be. Oral corticosteroids remain the
cornerstone treatment, possibly preceded by intravenous bolus in complicated
forms. In cases of glucocorticoid (GC) dependence or GC-related side effects, a
GC-sparing agent may be necessary. Methotrexate is one of the most used
treatments despite its low level of evidence and mild efficacy. Cyclophosphamide
and tocilizumab look promising but require validation in further studies. The
results for TNF-α blockers and azathioprine are disappointing. Preventing
complications of prolonged corticosteroid therapy is a world challenge and the
management of GC-induced osteoporosis is not the same from one country to
another. There is a significant risk of arterial thrombosis, mainly at treatment
onset, which may encourage to associate an antiplatelet therapy, especially in
patients with other cardiovascular risk factors. Place of statins in the
treatment of the disease is uncertain. OBJECTIVES: Randomised-controlled trials have recently proven the efficacy of
the interleukin (IL)-6 receptor antagonist tocilizumab (TCZ) in giant cell
arteritis (GCA). However, the mechanism of action of IL-6 blockade in this
disease is unknown. Moreover, the role of regulatory T (Treg) cells in the
pathogenesis of GCA remains underexplored. Given the plasticity of Tregs and the
importance of IL-6 in their biology, we hypothesised that TCZ might modulate the
Treg response in GCA. We therefore characterised the Treg compartment of
patients with GCA treated with TCZ.
METHODS: We classified 41 patients with GCA into three groups: active disease
(aGCA, n=11), disease remission on corticosteroids (rGCA-CS, n=19) and disease
remission on TCZ (rGCA-TCZ, n=11). Healthy controls (HCs) were included for
comparison. We determined the frequency, phenotype and function of peripheral
blood Tregs.
RESULTS: Patients with aGCA demonstrated a hypoproliferating Treg compartment
enriched in IL-17-secreting Tregs (IL-17+Tregs). Tregs in patients with aGCA
disproportionally expressed a hypofunctional isoform of Foxp3 that lacks exon 2
(Foxp3Δ2). Foxp3Δ2-expressing Tregs coexpressed CD161, a marker commonly
associated with the Th17 linage, significantly more often than full-length
Foxp3-expressing Tregs. Compared with those of HCs, GCA-derived Tregs
demonstrated impaired suppressor capacity. Treatment with TCZ, in contrast to CS
therapy, corrected the Treg abnormalities observed in aGCA. In addition, TCZ
treatment increased the numbers of activated Tregs (CD45RA-Foxp3high) and the
Treg expression of markers of trafficking (CCR4) and terminal differentiation
(CTLA-4).
CONCLUSIONS: TCZ may exert its therapeutic effects in GCA by increasing the
proliferation and activation of Tregs, and by reverting the pathogenic Treg
phenotype seen during active disease. Giant cell arteritis and Takayasu arteritis are the two major forms of
idiopathic large vessel vasculitis. High doses of glucocorticoids are effective
in inducing remission in both conditions, but relapses and recurrences are
common, requiring prolonged glucocorticoid treatment with the risk of the
related adverse events. Areas covered: In this article, we will review the
standard and biological treatment strategies in large vessel vasculitis, and we
will focus on the current approaches to these diseases. Expert commentary: The
results of treatment trials with conventional immunosuppressive agents such as
methotrexate, azathioprine, mycophenolate mofetil, and cyclophosphamide have
overall been disappointing. TNF-α blockers are ineffective in giant cell
arteritis, while observational evidence and a phase 2 randomized trial support
the use of tocilizumab in relapsing giant cell arteritis. Observational evidence
strongly supports the use of anti-TNF-α agents and tocilizumab in Takayasu
patients with relapsing disease. However biological agents are not curative, and
relapses remain common. Giant cell arteritis (GCA) is a systemic inflammatory vasculitis affecting
medium and large vessels with potentially sight and life-threatening
complications. Early diagnosis and prompt treatment are imperative in order to
prevent vision loss and progression of the disease. Erythrocyte sedimentation
rate (ESR) and C-reactive protein (CRP) are inflammatory markers which are
elevated in the majority of patients and support the diagnosis of GCA among
patients who present with typical symptoms. GCA is confirmed with superficial
temporal artery biopsy which demonstrates characteristic pathological findings.
Treatment of suspected ophthalmic involvement must be initiated urgently, even
when diagnostic studies are pending. High dose corticosteroid therapy is the
mainstay of treatment and is administered either intravenously or orally to
prevent further vision loss and treat systemic vasculitis. Oral corticosteroid
therapy is required for months to years with careful follow-up and periodic
laboratory evaluations with ESR and CRP. Corticosteroids are tapered gradually
over months and may be associated with complications such as hypertension,
diabetes mellitus, osteoporosis, psychosis, peptic ulcer disease, and infection.
Supplementation with calcium, vitamin D, bisphosphonate therapy, antimicrobial
prophylaxis, and initiation of a proton pump inhibitor or Histamine H2-receptor
antagonist should be considered. Recurrence of inflammation is common in GCA and
necessitates an escalation of corticosteroid dose. Adjunctive immunomodulatory
therapy may be considered in patients experiencing relapsing inflammation
despite high doses of corticosteroids or those with corticosteroid-induced
complications. Emerging evidence for adjunctive therapy with tocilizumab,
methotrexate, aspirin, angiotensin receptor blockers, and statins is encouraging
and may lead to a more mainstream role for these therapies among patients with
GCA. BACKGROUND: Giant cell arteritis is an inflammatory disorder of the medium- and
large-size arteries. Permanent visual loss related to arteritic anterior
ischemic optic neuropathy is among the most serious complications of this
disease and initial treatment usually consists of high dose corticosteroids.
There is no consensus in the literature concerning the optimal therapeutic
approach in giant cell arteritis patients with corticosteroid-resistant
arteritic anterior ischemic optic neuropathy.
CASE REPORT: A 73-year-old Caucasian female with biopsy-proven giant cell
arteritis developed an acute visual loss of the right eye due to arteritic
anterior ischemic optic neuropathy. Despite 5 daily methylprednisolone pulses,
systemic symptoms persisted and rapid involvement of the controlateral eye was
documented. Therefore, tocilizumab (humanised monoclonal antibody binding the
human interleukin-6 receptor) was introduced as a potential salvage therapy with
a swift consecutive resolution of the systemic symptoms and stabilization of the
ophthalmic lesions.
CONCLUSIONS: Although a late effect of steroids pulses cannot be formally ruled
out in this dramatic situation, tocilizumab likely offered a decisive effect in
preventing bilateral blindness and may have contributed to steroid tapering.
Tocilizumab may represent a new early effective second-line treatment option in
corticosteroid-resistant anterior ischemic optic neuropathy. More data are
needed to confirm this observation and to evaluate the safety profile of this
treatment. BACKGROUND: Giant-cell arteritis commonly relapses when glucocorticoids are
tapered, and the prolonged use of glucocorticoids is associated with side
effects. The effect of the interleukin-6 receptor alpha inhibitor tocilizumab on
the rates of relapse during glucocorticoid tapering was studied in patients with
giant-cell arteritis.
METHODS: In this 1-year trial, we randomly assigned 251 patients, in a 2:1:1:1
ratio, to receive subcutaneous tocilizumab (at a dose of 162 mg) weekly or every
other week, combined with a 26-week prednisone taper, or placebo combined with a
prednisone taper over a period of either 26 weeks or 52 weeks. The primary
outcome was the rate of sustained glucocorticoid-free remission at week 52 in
each tocilizumab group as compared with the rate in the placebo group that
underwent the 26-week prednisone taper. The key secondary outcome was the rate
of remission in each tocilizumab group as compared with the placebo group that
underwent the 52-week prednisone taper. Dosing of prednisone and safety were
also assessed.
RESULTS: Sustained remission at week 52 occurred in 56% of the patients treated
with tocilizumab weekly and in 53% of those treated with tocilizumab every other
week, as compared with 14% of those in the placebo group that underwent the
26-week prednisone taper and 18% of those in the placebo group that underwent
the 52-week prednisone taper (P<0.001 for the comparisons of either active
treatment with placebo). The cumulative median prednisone dose over the 52-week
period was 1862 mg in each tocilizumab group, as compared with 3296 mg in the
placebo group that underwent the 26-week taper (P<0.001 for both comparisons)
and 3818 mg in the placebo group that underwent the 52-week taper (P<0.001 for
both comparisons). Serious adverse events occurred in 15% of the patients in the
group that received tocilizumab weekly, 14% of those in the group that received
tocilizumab every other week, 22% of those in the placebo group that underwent
the 26-week taper, and 25% of those in the placebo group that underwent the
52-week taper. Anterior ischemic optic neuropathy developed in one patient in
the group that received tocilizumab every other week.
CONCLUSIONS: Tocilizumab, received weekly or every other week, combined with a
26-week prednisone taper was superior to either 26-week or 52-week prednisone
tapering plus placebo with regard to sustained glucocorticoid-free remission in
patients with giant-cell arteritis. Longer follow-up is necessary to determine
the durability of remission and safety of tocilizumab. (Funded by F. Hoffmann-La
Roche; ClinicalTrials.gov number, NCT01791153 .). Despite the progress in the last years on the field of vasculitides, there are
several unmet needs regarding classification, disease activity assessment,
predictors of flares and complications, and type of treatment for the different
forms. The 1990 American College of Rheumatology (ACR) classification criteria
currently used to define giant cell arteritis and Takayasu arteritis were
designed to discriminate between different types of vasculitides but not to
differentiate vasculitis from other disorders. Recently, efforts have been made
to overcome the shortcomings of the ACR criteria. The lack of an accepted
definition of disease activity in large-vessel vasculitides presents a major
challenge in creating useful and valid outcome tools for the assessment of
disease course. Identification of predictors of flares can aid in optimizing
therapeutic strategies, minimizing disease flares, and reducing
treatment-related side effects. It is furthermore important to recognize and
characterize the risk factor that might predict the manifestations associated
with poor outcome and prognosis. Two RCTs have evidenced the efficacy of
tocilizumab in addition to glucocorticoids (GCs) in the treatment of giant cell
arteritis (GCA). However, the role of tocilizumab or other biological agents
without GCs needs to be investigated. Recent observational studies have
suggested that rituximab is also effective in patients with eosinophilic
granulomatosis with polyangiitis and in antineutrophil cytoplasmic antibodies
(ANCA)-negative patients with granulomatosis with polyangiitis and microscopic
polyangiitis. Rituximab or anti-TNF alfa may represent a possible alternative
therapy in case of refractory or difficult to treat polyarteritis nodosa (PAN)
patients. The new International Criteria for Behçet's Disease have shown a
better sensitivity and a better accuracy compared to the older International
Study Group on Behçet's Disease criteria. The EULAR recommendations for the
management of Behçet's disease (BD) have been recently updated. However, the
treatment of refractory disease is still a real challenge. Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are the two main large
vessel vasculitides. They share some similarities regarding their clinical,
radiological and histological presentations but some pathogenic processes in GCA
and TAK are activated differently, thus explaining their different sensitivity
to biological therapies. The treatment of GCA and TAK essentially relies on
glucocorticoids. However, thanks to major progress in our understanding of their
pathogenesis, the role of biological therapies in the treatment of these two
vasculitides is expanding, especially in relapsing or refractory diseases. In
this review, the efficacy, the safety and the limits of the main biological
therapies ever tested in GCA and TAK are discussed. Briefly, anti TNF-α agents
appear to be effective in treating TAK but not GCA. Recent randomized
placebo-controlled trials have reported on the efficacy and safety of abatacept
and mostly tocilizumab in inducing and maintaining remission of GCA. Abatacept
was not effective in TAK and robust data are still lacking to draw any
conclusions concerning the use of tocilizumab in TAK. Furthermore, ustekinumab
appears promising in relapsing/refractory GCA whereas rituximab has been
reported to be effective in only a few cases of refractory TAK patients. If a
biological therapy is indicated, and in light of the data discussed in this
review, the first choice would be tocilizumab in GCA and anti-TNF-α agents
(mainly infliximab) in TAK. |
Is there a link between nuclear position and DNA repair pathway choice? | Yes. Nuclear position dictates DNA repair pathway choice, thus revealing a new level of regulation in DSB repair controlled by spatial organization of DNA within the nucleus. | Faithful DNA repair is essential to avoid chromosomal rearrangements and promote
genome integrity. Nuclear organization has emerged as a key parameter in the
formation of chromosomal translocations, yet little is known as to whether DNA
repair can efficiently occur throughout the nucleus and whether it is affected
by the location of the lesion. Here, we induce DNA double-strand breaks (DSBs)
at different nuclear compartments and follow their fate. We demonstrate that
DSBs induced at the nuclear membrane (but not at nuclear pores or nuclear
interior) fail to rapidly activate the DNA damage response (DDR) and repair by
homologous recombination (HR). Real-time and superresolution imaging reveal that
DNA DSBs within lamina-associated domains do not migrate to more permissive
environments for HR, like the nuclear pores or the nuclear interior, but instead
are repaired in situ by alternative end-joining. Our results are consistent with
a model in which nuclear position dictates the choice of DNA repair pathway,
thus revealing a new level of regulation in DSB repair controlled by spatial
organization of DNA within the nucleus. |
Can non ubiquitinated Tomm20 promote mitophagy? | The translocase of outer mitochondrial membrane 20 (Tomm20), is a mitochondrial translocase that, when ubiquitinated, promotes mitophagy. | |
Does SARM1 deletion cause neurodegeneration? | Mouse strain with Sarm1 deletion (Sarm1-/-) is highly resistant to axon neurodegeneration. | Accruing evidence suggests that prion-like behavior of fibrillar forms of
α-synuclein, β-amyloid peptide and mutant huntingtin are responsible for the
spread of the lesions that characterize Parkinson disease, Alzheimer disease and
Huntington disease, respectively. It is unknown whether these distinct protein
assemblies are transported within and between neurons by similar or distinct
mechanisms. It is also unclear if neuronal death or injury is required for
neuron-to-neuron transfer. To address these questions, we used mouse primary
cortical neurons grown in microfluidic devices to measure the amounts of
α-synuclein, Aβ42 and HTTExon1 fibrils transported by axons in both directions
(anterograde and retrograde), as well as to examine the mechanism of their
release from axons after anterograde transport. We observed that the three
fibrils were transported in both anterograde and retrograde directions but with
strikingly different efficiencies. The amount of Aβ42 fibrils transported was
ten times higher than that of the other two fibrils. HTTExon1 was efficiently
transported in the retrograde direction but only marginally in the anterograde
direction. Finally, using neurons from two distinct mutant mouse strains whose
axons are highly resistant to neurodegeneration (Wld(S) and Sarm1(-/-)), we
found that the three different fibrils were secreted by axons after anterograde
transport, in the absence of axonal lysis, indicating that trans-neuronal spread
can occur in intact healthy neurons. In summary, fibrils of α-synuclein, Aβ42
and HTTExon1 are all transported in axons but in directions and amounts that are
specific of each fibril. After anterograde transport, the three fibrils were
secreted in the medium in the absence of axon lysis. Continuous secretion could
play an important role in the spread of pathology between neurons but may be
amenable to pharmacological intervention. |
Is DNA polymerase θ involved in DNA repair? | Yes, DNA polymerase θ protects against genomic instability via an alternative end-joining repair pathway for DNA double-strand breaks. | DNA polymerase θ protects against genomic instability via an alternative
end-joining repair pathway for DNA double-strand breaks. Polymerase θ is
overexpressed in breast, lung and oral cancers, and reduction of its activity in
mammalian cells increases sensitivity to double-strand break-inducing agents,
including ionizing radiation. Reported here are crystal structures of the
C-terminal polymerase domain from human polymerase θ, illustrating two potential
modes of dimerization. One structure depicts insertion of ddATP opposite an
abasic-site analog during translesion DNA synthesis. The second structure
describes a cognate ddGTP complex. Polymerase θ uses a specialized thumb
subdomain to establish unique upstream contacts to the primer DNA strand,
including an interaction with the 3'-terminal phosphate from one of five
distinctive insertion loops. These observations demonstrate how polymerase θ
grasps the primer to bypass DNA lesions or extend poorly annealed DNA termini to
mediate end-joining. New research shows that DNA polymerase θ is a key player in PARP-mediated DNA
damage repair and essential for the survival of cancer cells where homologous
recombination is compromised. Polθ could be a biomarker for PARP-inhibitor
response, and is a potential therapeutic target for overcoming resistance to
these drugs. DNA polymerase θ (Pol θ) is implicated in various cellular processes including
double-strand break repair and apurinic/apyrimidinic site bypass. Because Pol θ
expression correlates with poor cancer prognosis, the ability of Pol θ to bypass
the C4'-oxidized abasic site (C4-AP) and 2-deoxyribonolactone (L), which are
generated by cytotoxic agents, is of interest. Translesion synthesis and
subsequent extension by Pol θ past C4-AP or L and an abasic site (AP) or its
tetrahydrofuran analogue (F) was examined. Pol θ conducts translesion synthesis
on templates containing AP and F with similar efficiencies and follows the
"A-rule," inserting nucleotides in the order A > G > T. Translesion synthesis on
templates containing C4-AP and L is less efficient than AP and F, and the
preference for A insertion is reduced for L and absent for C4-AP. Extension past
all abasic lesions (AP, F, C4-AP, and L) was significantly less efficient than
translesion synthesis and yielded deletions caused by the base one or two
nucleotides downstream from the lesion being used as a template, with the latter
being favored. These results suggest that bypass of abasic lesions by Pol θ is
highly mutagenic. |
List drugs that are included in the Vosevi polypill. | Vosevi pill includes sofosbuvir, velpatasvir and voxilaprevir. It is approved by the US Food and Drug Administration (FDA) for adult patients with chronic hepatitis C virus (HCV) infection without cirrhosis or with compensated cirrhosis (Child-Pugh A) who have: genotype 1, 2, 3, 4, 5, or 6 infection and have previously been treated with an HCV regimen containing an NS5A inhibitor; and genotype 1a or 3 infection and have previously been treated with an HCV regimen containing sofosbuvir without an NS5A inhibitor. | |
What part of what body organ controls the circadian clock? | the suprachiasmatic nucleus (SCN) of the hypothalamus acts as the central clock in mammals, the circadian expression of clock genes | The suprachiasmatic nucleus (SCN) controls circadian rhythms in mammals. The SCN
may also participate in regulating body metabolism and energy. Similar to other
hypothalamic nuclei, the SCN have been reported to contain glucose-sensitive
neurons and receptors for the adipose tissue hormone, leptin. Here we
investigated leptin effects on the SCN clock. Our results demonstrate that the
SCN circadian clock, when isolated in vitro, can be phase advanced by leptin in
a dose-dependent fashion that does not require non-SCN hypothalamic tissue.
Phase advances are induced at all circadian times except late subjective night.
These data suggest that peripheral signals of energy and metabolism directly
modulate the circadian pacemaker in mammals. The mammalian circadian system consists of a central oscillator in the
suprachiasmatic nucleus of the hypothalamus, which coordinates peripheral clocks
in organs throughout the body. Although circadian clocks control the rhythmic
expression of a large number of genes involved in metabolism and other aspects
of circadian physiology, the consequences of genetic disruption of
circadian-controlled pathways remain poorly defined. Here we report that the
targeted disruption of Nocturnin (Ccrn4l) in mice, a gene that encodes a
circadian deadenylase, confers resistance to diet-induced obesity. Mice lacking
Nocturnin remain lean on high-fat diets, with lower body weight and reduced
visceral fat. However, unlike lean lipodystrophic mouse models, these mice do
not have fatty livers and do not exhibit increased activity or reduced food
intake. Gene expression data suggest that Nocturnin knockout mice have deficits
in lipid metabolism or uptake, in addition to changes in glucose and insulin
sensitivity. Our data support a pivotal role for Nocturnin downstream of the
circadian clockwork in the posttranscriptional regulation of genes necessary for
nutrient uptake, metabolism, and storage. The suprachiasmatic nucleus of the brain is the circadian center, relaying
rhythmic environmental and behavioral information to peripheral tissues to
control circadian physiology. As such, central clock dysfunction can alter
systemic homeostasis to consequently impair peripheral physiology in a manner
that is secondary to circadian malfunction. To determine the impact of circadian
clock function in organ transplantation and dissect the influence of intrinsic
tissue clocks versus extrinsic clocks, we implemented a blood vessel grafting
approach to surgically assemble a chimeric mouse that was part wild-type (WT)
and part circadian clock mutant. Arterial isografts from donor WT mice that had
been anastamosed to common carotid arteries of recipient WT mice (WT:WT)
exhibited no pathology in this syngeneic transplant strategy. Similarly, when WT
grafts were anastamosed to mice with disrupted circadian clocks, the structural
features of the WT grafts immersed in the milieu of circadian malfunction were
normal and absent of lesions, comparable to WT:WT grafts. In contrast, aortic
grafts from Bmal1 knockout (KO) or Period-2,3 double-KO mice transplanted into
littermate control WT mice developed robust arteriosclerotic disease. These
lesions observed in donor grafts of Bmal1-KO were associated with up-regulation
in T-cell receptors, macrophages, and infiltrating cells in the vascular grafts,
but were independent of hemodynamics and B and T cell-mediated immunity. These
data demonstrate the significance of intrinsic tissue clocks as an autonomous
influence in experimental models of arteriosclerotic disease, which may have
implications with regard to the influence of circadian clock function in organ
transplantation. Although circadian rhythms in mammalian physiology and behavior are dependent
upon a biological clock in the suprachiasmatic nuclei (SCN) of the hypothalamus,
the molecular mechanism of this clock is in fact cell autonomous and conserved
in nearly all cells of the body. Thus, the SCN serves in part as a "master
clock," synchronizing "slave" clocks in peripheral tissues, and in part directly
orchestrates circadian physiology. In this chapter, we first consider the
detailed mechanism of peripheral clocks as compared to clocks in the SCN and how
mechanistic differences facilitate their functions. Next, we discuss the
different mechanisms by which peripheral tissues can be entrained to the SCN and
to the environment. Finally, we look directly at how peripheral oscillators
control circadian physiology in cells and tissues. Circadian rhythms are the approximate 24-h biological cycles that function to
prepare an organism for daily environmental changes. They are driven by the
molecular clock, a transcriptional:translational feedback mechanism that in
mammals involves the core clock genes Bmal1, Clock, Per1/2, and Cry1/2. The
molecular clock is present in virtually all cells of an organism. The central
clock in the suprachiasmatic nucleus (SCN) has been well studied, but the clocks
in the peripheral tissues, such as heart and skeletal muscle, have just begun to
be investigated. Skeletal muscle is one of the largest organs in the body,
comprising approximately 45% of total body mass. More than 2300 genes in
skeletal muscle are expressed in a circadian pattern, and these genes
participate in a wide range of functions, including myogenesis, transcription,
and metabolism. The circadian rhythms of skeletal muscle can be entrained both
indirectly through light input to the SCN and directly through time of feeding
and activity. It is critical for the skeletal muscle molecular clock not only to
be entrained to the environment but also to be in synchrony with rhythms of
other tissues. When circadian rhythms are disrupted, the observed effects on
skeletal muscle include fiber-type shifts, altered sarcomeric structure, reduced
mitochondrial respiration, and impaired muscle function. Furthermore, there are
detrimental effects on metabolic health, including impaired glucose tolerance
and insulin sensitivity, which skeletal muscle likely contributes to considering
it is a key metabolic tissue. These data indicate a critical role for skeletal
muscle circadian rhythms for both muscle and systems health. Future research is
needed to determine the mechanisms of molecular clock function in skeletal
muscle, identify the means by which skeletal muscle entrainment occurs, and
provide a stringent comparison of circadian gene expression across the diverse
tissue system of skeletal muscle. The environmental light-dark (LD) cycle entrains the central circadian clock
located in the suprachiasmatic nucleus (SCN) of mammals. The present study
examined the effects of disrupted LD cycles on peripheral clocks in mice housed
under a normal 12 h light-12 h dark cycle (LD 12:12) or an ultradian LD 3:3
cycle. Drinking behavior seemed to be free-running with a long period (26.03 h)
under ultradian LD 3:3 cycles, in addition to light-induced direct suppression
(masking effect). Core body temperature completely lost robust circadian rhythm
and acquired a 6-h rhythm with a low amplitude under LD 3:3. Robust circadian
expression of Per1, Per2, Clock and Bmal1 mRNAs was similarly flattened to
intermediate levels in the liver, heart and white adipose tissue under LD 3:3.
Robust circadian expression of Rev-erbα mRNA was completely damped in these
tissues. Circadian expression of Dbp, a clock-controlled gene, was also
disrupted in these tissues from mice housed under LD 3:3. The aberrant LD cycle
seemed to induce the loss of circadian gene expression at the level of
transcription, because rhythmic pre-mRNA expression of these genes was also
abolished under LD 3:3. In addition to the direct effect of the aberrant LD
cycle, abolished systemic time cues such as those of plasma corticosterone and
body temperature might be involved in the disrupted expression of these
circadian genes under LD 3:3. Our findings suggest that disrupted environmental
LD cycles abolish the normal oscillation of peripheral clocks and induce
internal desynchrony in mammals. Although, the suprachiasmatic nucleus (SCN) of the hypothalamus acts as the
central clock in mammals, the circadian expression of clock genes has been
demonstrated not only in the SCN, but also in peripheral tissues and brain
regions outside the SCN. However, the physiological roles of extra-SCN circadian
clocks in the brain remain largely elusive. In response, we generated
Nkx2.1-Bmal1-/- mice in which Bmal1, an essential clock component, was
genetically deleted specifically in the ventral forebrain, including the
preoptic area, nucleus of the diagonal band, and most of the hypothalamus except
the SCN. In these mice, as expected, PER2::LUC oscillation was drastically
attenuated in the explants of mediobasal hypothalamus, whereas it was maintained
in those of the SCN. Although, Nkx2.1-Bmal1-/- mice were rhythmic and nocturnal,
they showed altered patterns of locomotor activity during the night in a 12:12-h
light:dark cycle and during subjective night in constant darkness. Control mice
were more active during the first half than the second half of the dark phase or
subjective night, whereas Nkx2.1-Bmal1-/- mice showed the opposite pattern of
locomotor activity. Temporal patterns of sleep-wakefulness and feeding also
changed accordingly. Such results suggest that along with mechanisms in the SCN,
local Bmal1-dependent clocks in the ventral forebrain are critical for
generating precise temporal patterns of circadian behaviors. The nerve center responsible for controlling our circadian rhythm is located in
a cluster of cells known as the suprachiasmatic nucleus in the hypothalamus.
Various physiological functions such as sleep, arousal, blood pressure, body
temperature, and hormone secretion are regulated in a 24-hour rhythm by this
circuit. Somatic cells of other organs have a peripheral clock gene and by
synchronizing the rhythm of the central and peripheral clocks, it is possible to
live a healthy life. Due to aging and degenerative disease, circadian rhythm
gradually collapses. Factors that can contribute to this include reduced
expression of the time gene associated with photo stimulation, a reduction in
neurotransmitter levels, and reduced melatonin production. Biological clocks
play an important role in our emotions, cognitive function, and behavior. Sleep
disorders and metabolic disease related to the circadian rhythm affect metabolic
and endocrine activities via the autonomic nervous system and the intestinal
bacterial flora. Shift work disorder is associated with insomnia and excessive
drowsiness as individuals often work during their sleeping hours. Now time
management is placed at the center of our society, and it is important to
evaluate the medical risk of engaging in shift work. In frontotemporal dementia
(FTD), the stereotypical behaviors may be associated with time. In some
patients, multiple timed behaviors occupy a considerable part of the patient's
daily life. Stereotypical behaviors in FTD are often considered in contrast to
obsessive-compulsive disease (OCD). Studies of OCD have found a close
correlation between clinical symptoms, cognitive function, and brain function. The suprachiasmatic nucleus houses the central circadian clock and is
characterized by the timely regulated expression of clock genes. However,
neurons of the cerebellar cortex also contain a circadian oscillator with
circadian expression of clock genes being controlled by the suprachiasmatic
nucleus. It has been suggested that the cerebellar circadian oscillator is
involved in food anticipation, but direct molecular evidence of the role of the
circadian oscillator of the cerebellar cortex is currently unavailable. To
investigate the hypothesis that the circadian oscillator of the cerebellum is
involved in circadian physiology and food anticipation, we therefore by use of
Cre-LoxP technology generated a conditional knockout mouse with the core clock
gene Arntl deleted specifically in granule cells of the cerebellum, since
expression of clock genes in the cerebellar cortex is mainly located in this
cell type. We here report that deletion of Arntl heavily influences the
molecular clock of the cerebellar cortex with significantly altered and
arrhythmic expression of other central clock and clock-controlled genes. On the
other hand, daily expression of clock genes in the suprachiasmatic nucleus was
unaffected. Telemetric registrations in different light regimes did not detect
significant differences in circadian rhythms of running activity and body
temperature between Arntl conditional knockout mice and controls. Furthermore,
food anticipatory behavior did not differ between genotypes. These data suggest
that Arntl is an essential part of the cerebellar oscillator; however, the
oscillator of the granular layer of the cerebellar cortex does not control
traditional circadian parameters or food anticipation. |
Which algorithms are used for compression of SAM files? | The most popular format for genomic data is the SAM (Sequence Alignment/Map) format, which contains information such as alignment, quality values, etc. These files are large (on the order of terabytes), which necessitates compression. GeneComp, NGC, SAMZIP and QVZ are algorithms which perform compression of data stored in SAM files. | Research in bioinformatics primarily involves collection and analysis of a large
volume of genomic data. Naturally, it demands efficient storage and transfer of
this huge amount of data. In recent years, some research has been done to find
efficient compression algorithms to reduce the size of various sequencing data.
One way to improve the transmission time of large files is to apply a maximum
lossless compression on them. In this paper, we present SAMZIP, a specialized
encoding scheme, for sequence alignment data in SAM (Sequence Alignment/Map)
format, which improves the compression ratio of existing compression tools
available. In order to achieve this, we exploit the prior knowledge of the file
format and specifications. Our experimental results show that our encoding
scheme improves compression ratio, thereby reducing overall transmission time
significantly. MOTIVATION: Recent advancements in sequencing technology have led to a drastic
reduction in the cost of sequencing a genome. This has generated an
unprecedented amount of genomic data that must be stored, processed and
transmitted. To facilitate this effort, we propose a new lossy compressor for
the quality values presented in genomic data files (e.g. FASTQ and SAM files),
which comprise roughly half of the storage space (in the uncompressed domain).
Lossy compression allows for compression of data beyond its lossless limit.
RESULTS: The proposed algorithm QVZ exhibits better rate-distortion performance
than the previously proposed algorithms, for several distortion metrics and for
the lossless case. Moreover, it allows the user to define any quasi-convex
distortion function to be minimized, a feature not supported by the previous
algorithms. Finally, we show that QVZ-compressed data exhibit better performance
in the genotyping than data compressed with previously proposed algorithms, in
the sense that for a similar rate, a genotyping closer to that achieved with the
original quality values is obtained.
AVAILABILITY AND IMPLEMENTATION: QVZ is written in C and can be downloaded from
https://github.com/mikelhernaez/qvz.
CONTACT: [email protected] or [email protected] or [email protected]
SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics
online. MOTIVATION: Next generation sequencing machines produce vast amounts of genomic
data. For the data to be useful, it is essential that it can be stored and
manipulated efficiently. This work responds to the combined challenge of
compressing genomic data, while providing fast access to regions of interest,
without necessitating decompression of whole files.
RESULTS: We describe CSAM (Compressed SAM format), a compression approach
offering lossless and lossy compression for SAM files. The structures and
techniques proposed are suitable for representing SAM files, as well as
supporting fast access to the compressed information. They generate more compact
lossless representations than BAM, which is currently the preferred lossless
compressed SAM-equivalent format; and are self-contained, that is, they do not
depend on any external resources to compress or decompress SAM files.
AVAILABILITY AND IMPLEMENTATION: An implementation is available at
https://github.com/rcanovas/libCSAM CONTACT: [email protected]
Information: Supplementary data is available at Bioinformatics online. The affordability of DNA sequencing has led to unprecedented volumes of genomic
data. These data must be stored, processed, and analyzed. The most popular
format for genomic data is the SAM format, which contains information such as
alignment, quality values, etc. These files are large (on the order of
terabytes), which necessitates compression. In this work we propose a new
reference-based compressor for SAM files, which can accommodate different levels
of compression, based on the specific needs of the user. In particular, the
proposed compressor GeneComp allows the user to perform lossy compression of the
quality scores, which have been proven to occupy more than half of the
compressed file (when losslessly compressed). We show that the proposed
compressor GeneComp overall achieves better compression ratios than previously
proposed algorithms when working on lossless mode. |
What does MetaHIT stand for? | Metagenomics of the Human Intestinal Tract (MetaHIT) project are focusing mainly on the human microbiome | |
List 4 drugs used to treat opioid addiction or overdose | Suboxone (buprenorphine/naloxone) and methadone are used to assist in opioid withdrawal and Naloxone is used to treat overdoses | The practice of prescribing opioid drugs for opioid dependent patients in the
U.S. has been subjected to special government scrutiny for almost 100 years.
From 1920 until 1964, doctors who used opioids to treat addicts risked federal
and/or state criminal prosecution. Although that period ended when oral
methadone maintece was established as legitimate medical practice, public
concern about methadone diversion and accidental overdose fatalities, combined
with political pressure from both hostile bureaucracies and groups committed to
drug-free treatments, led to the development of unprecedented and detailed Food
and Drug Administration (FDA) regulations that specified the manner in which
methadone (and later, levo-alpha-acetyl methadol, or levomethadyl acetate,
(LAAM)) could be provided. In 1974, Congress gave the Drug Enforcement
Administration (DEA) additional oversight of methadone treatment programs.
Efforts to liberalize the FDA regulations over the past 30 years have been
resisted by both the DEA and existing treatment providers. Additional
flexibility for clinicians may evolve from the most recent effort to create an
accreditation system to replace some of the FDA regulations. The development of
buprenorphine, a partial opioid agonist, as an effective treatment for opioid
addiction reopened the possibility for having a less burdensome oversight
process, especially because of its reduced toxicity if ingested by non-tolerant
individuals. New legislation, the Drug Addiction Treatment Act (DATA) of 2000,
created an opportunity for clinicians with special training to be exempted from
both federal methadone regulations and the requirement to obtain a special DEA
license when using buprenorphine to treat addicts. Some details of how the DATA
was developed, moved through Congress, and signed into law are described. Although the synthetic opioid buprenorphine has been available clinically for
almost 30 years, its use has only recently become much more widespread for the
treatment of opioid addiction. The pharmacodynamic and pharmacokinetic profiles
of buprenorphine make it unique in the armamentarium of drugs for the treatment
of opioid addiction. Buprenorphine has partial mu-opioid receptor agonist
activity and is a kappa-opioid receptor antagonist; hence, it can substitute for
other micro-opioid receptor agonists, yet is less apt to produce overdose
reactions or dysphoria. On the other hand, buprenorphine can block the effects
of opioids such as heroin (diamorphine) and morphine, and can even precipitate
withdrawal in individuals physically dependent upon these drugs. Buprenorphine
has significant sublingual bioavailability and a long half-life, making
administration on a less than daily basis possible. Furthermore, its
discontinuation is associated with only a mild withdrawal syndrome. Clinical
trials have demonstrated that sublingual buprenorphine is effective in both
maintece therapy and detoxification of individuals addicted to opioids. The
introduction of a sublingual formulation combining naloxone with buprenorphine
further reduces the risk of diversion to illicit intravenous use. Because of its
relative safety and lower risk of illegal diversion, buprenorphine has been made
available in several countries for treating opioid addiction in the private
office setting, greatly enhancing treatment options for this condition. Opioid dependence is a problem of national concern, especially with dramatically
increased rates of abuse and dependence of prescription opioids. The current
article provides an up-to-date review of the literature on opioid dependence
treatment, with a focus on conclusions drawn by experts in the field (e.g.,
Cochrane reviews and meta-analyses) and methodologically rigorous studies (e.g.,
randomized controlled trials). We describe the major classes of drug treatments
available, including opioid agonist (e.g., methadone, buprenorphine, LAAM),
antagonist (e.g., naltrexone) and non-opioid pharmacotherapies (e.g., alpha2
adrenergic agonists). These treatments are discussed in the context of
detoxification and long term treatment options such as abstinence-based and
maintece strategies. We review the state of the literature as to prevention
of opioid overdose and discuss the widespread problem of comorbidity among
opioid-dependent populations. We also focus prominently on evidence for
inclusion of psychosocial approaches in treatment regimens, either as
stand-alone or in conjunction with psychopharmacological options. Opioid use and overdose rates have risen to epidemic levels in the United States
during the past decade. Fortunately, there are effective medications (ie,
methadone, buprenorphine, and oral and injectable naltrexone) available for the
treatment of opioid addiction. Each of these medications is approved for use in
conjunction with psychosocial treatment; however, there is a dearth of empirical
research on the optimal psychosocial interventions to use with these
medications. In this systematic review, we outline and discuss the findings of 3
prominent prior reviews and 27 recent publications of empirical studies on this
topic. The most widely studied psychosocial interventions examined in
conjunction with medications for opioid addiction were contingency management
and cognitive behavioral therapy, with the majority focusing on methadone
treatment. The results generally support the efficacy of providing psychosocial
interventions in combination with medications to treat opioid addictions,
although the incremental utility varied across studies, outcomes, medications,
and interventions. The review highlights significant gaps in the literature and
provides areas for future research. Given the enormity of the current opioid
problem in the United States, it is critical to gain a better understanding of
the most effective ways to deliver psychosocial treatments in conjunction with
these medications to improve the health and well-being of individuals suffering
from opioid addiction. Buprenorphine office-based opioid maintece is an increasingly common form of
treatment for opioid use disorders. However, total prescribing has not kept pace
with the current opioid and overdose epidemic and access remains scarce among
the underserved. This study sought to assess current provider attitudes and
clinical practices among a targeted sample of primarily New York City public
sector buprenorphine prescribers. A cross-sectional online survey purposefully
sampled buprenorphine prescribers in NYC with a focus on those serving Medicaid
and uninsured patient populations. Expert review of local provider networks,
snowball referrals, and in-person networking generated an email list, which
received a survey link. A brief 25-question instrument queried provider and
practice demographics, prescribing practices including induction approaches and
attitudes regarding common hot topics (e.g., buprenorphine diversion, prescriber
patient limits, insurance issues, ancillary treatments). Of 132 email
invitations, N=72 respondents completed (n=64) or partially completed (n=8) the
survey between January and April 2016. Most (79%) were Medicaid providers in
non-psychiatric specialties (72%), working in a hospital-based or community
general practice (51%), and board-certified in addiction medicine or psychiatry
(58%). Practice sizes were generally 100 patients or fewer (71%); many providers
(64%) individually prescribed buprenorphine <25% of total practice time to a
median 23 patients (mean 31, range 0-102). Unobserved (home) induction for new
patients was a common practice: 49% predomitly prescribed unobserved
induction; 16% mixed unobserved and observed inductions. Adjunctive psychosocial
counseling was routinely recommended (46%) or considered on a case-by-case basis
(17%) versus mandated (37%). Medication prior authorization requirements were
the highest rated barriers to practice, followed by inadequate clinic space,
limited clinic time and/or support staff, and inadequate psychiatric services
for dual diagnoses. Buprenorphine diversion was not rated as an important
practice barrier. In conclusion, this targeted survey of buprenorphine
prescribers in NYC treating primarily underserved populations showed a
consistent pattern of part-time prescribing to modest volumes of patients,
routine use of unobserved buprenorphine induction, and primarily elective
referrals to psychosocial counseling. Barriers to prescribing included prior
authorization requirements, lack of clinical resources (space, staff) and
psychiatric services. Federal and local efforts to reduce such barriers may
improve buprenorphine access among the underserved. The prevalence of opioid abuse in the United States has been steadily increasing
over the last several years among many major demographics, including pregt
women. Rise in prenatal opioid abuse has resulted in subsequent escalation of
neonatal abstinence syndrome incidence, prompting the US Congress to pass the
Protecting Our Infants Act of 2015. This act specifically calls for a critical
review of current treatment options for prenatal opioid abuse which may
ultimately lead to the development of better therapies and a decreased incidence
of neonatal abstinence syndrome. Currently, the American College of
Obstetricians and Gynecologists recommends methadone, buprenorphine, or
buprenorphine/naloxone in the treatment of prenatal opioid abuse. In this
review, each maintece therapy treatment option is discussed and compared
revealing inconsistencies in postpartum retention rates, effects on fetal
development, and availability to patients due to restrictions in health care
coverage. Although each of these treatment options reduces opioid abuse and
potential negative outcomes for the fetus, the shortcomings of these drugs
highlight the overarching need for an improved standard of care. Drug developers
and lawmakers should consider that affordability, coverage by health insurance,
and success in retention rates substantially impacts the decision of the patient
and healthcare provider regarding utilization of a particular opioid maintece
therapy. Drug overdose is a leading cause of injury death in the United States; 47,055
fatal drug overdoses were reported in 2014, a 6.5% increase from the previous
year (1), driven by opioid use disorder (2,3). Methadone is an opioid prescribed
for pain management and is also provided through opioid treatment programs to
treat opioid use disorders. Because methadone might remain in a person's system
long after the pain-relieving benefits have been exhausted, it can cause slow or
shallow breathing and dangerous changes in heartbeat that might not be perceived
by the patient (4,5). In December 2006, the Food and Drug Administration issued
a Public Health Advisory that alerted health care professionals to reports of
death and life-threatening adverse events, such as respiratory depression and
cardiac arrhythmias, in patients receiving methadone (4); in January 2008, a
voluntary manufacturer restriction limited distribution of the 40 mg formulation
of methadone.* CDC analyzed state mortality and health care data and preferred
drug list (PDL) policies to 1) compare the percentage of deaths involving
methadone with the rate of prescribing methadone for pain, 2) characterize
variation in methadone prescribing among payers and states, and 3) assess
whether an association existed between state Medicaid reimbursement PDL policies
and methadone overdose rates. The analyses found that, from 2007 to 2014, large
declines in methadone-related overdose deaths occurred. Prescriptions for
methadone accounted for 0.85% of all opioid prescriptions for pain in the
commercially insured population and 1.1% in the Medicaid population. In
addition, an association was observed between Medicaid PDLs requiring prior
authorization for methadone and lower rates of methadone overdose among Medicaid
enrollees. PDL policies requiring prior authorization might help to reduce the
number of methadone overdoses. |
Can nanoparticles be used for afterglow imaging? | Nanoparticles are used for afterglow imaging. | Afterglow or persistent luminescence eliminates the need for light excitation
and thus circumvents the issue of autofluorescence, holding promise for
molecular imaging. However, current persistent luminescence agents are rare and
limited to inorganic oparticles. This study reports the design principle,
synthesis, and proof-of-concept application of organic semiconducting
oparticles (OSNs) with ultralong phosphorescence for in vivo afterglow
imaging. The design principle leverages the formation of aggregates through a
top-down oparticle formulation to greatly stabilize the triplet excited
states of a phosphorescent molecule. This prolongs the particle luminesce to the
timescale that can be detected by the commercial whole-animal imaging system
after removal of external light source. Such ultralong phosphorescent of OSNs is
inert to oxygen and can be repeatedly activated, permitting imaging of lymph
nodes in living mice with a high signal-to-noise ratio. This study not only
introduces the first category of water-soluble ultralong phosphorescence organic
oparticles but also reveals a universal design principle to prolong the
lifetime of phosphorescent molecules to the level that can be effective for
molecular imaging. |
Describe mechanism of action of Romosozumab. | Romosozumab, a humanized monoclonal antibody that binds to sclerostin, prevents sclerostin from exerting this inhibitory effect. In the presence of romosozumab, the Wnt signaling pathway is activated leading to bone formation and bone mineral density gain. It is used for osteoporosis treatment. | INTRODUCTION: Disorders with inactivating mutations of the SOST gene result in
reduced or absent expression of sclerostin and are associated with high bone
mass. Sclerostin is an important regulator of bone formation due to its
inhibitory actions in the osteoanabolic Wnt signaling pathway. Advances in
understanding the mechanisms of action of this signaling molecule have led to
the development of a pharmacological inhibitor of sclerostin with potential
clinical applications as an osteoanabolic drug for the treatment of
osteoporosis.
AREAS COVERED: Romosozumab is the first humanized monoclonal sclerostin antibody
to be tested in clinical trials. Similar to preclinical animal studies with
sclerostin antibodies, initial clinical studies show that romosozumab increases
bone formation and bone mineral density.
EXPERT OPINION: Blocking sclerostin action with romosozumab is a promising new
therapeutic approach to osteoanabolic therapy of osteoporosis; efficacy and
safety data on large controlled studies are awaited. The Wnt pathway has an important role in bone formation. Inactivation of
sclerostin, an inhibitor of this pathway, has been associated with increased
bone mass both in animal experiments and in human clinical trials. Romosozumab
is a humanized monoclonal antibody targeting sclerostin. Preclinical studies
showed that this antibody primarily increases bone formation resulting in
increased bone mineral density. Initial studies carried out in humans are in
line with data obtained in animals. If these results are confirmed in larger
studies with fracture end-points, this monoclonal antibody with its anabolic
action, will become a key drug in the treatment of osteoporosis. Since the identification of osteoporosis as a major health issue in aging
populations and the subsequent development of the first treatment modalities for
its management, considerable progress has been made in our understanding of the
mechanisms controlling bone turnover and disease pathophysiology, thus enabling
the pinpointing of new targets for intervention. This progress, along with
advances in biotechnology, has rendered possible the development of ever more
sophisticated treatments employing novel mechanisms of action. Denosumab, a
monoclonal antibody against RANKL, approved for the treatment of postmenopausal
and male osteoporosis, significantly and continuously increases bone mineral
density (BMD) and maintains a low risk of vertebral, non-vertebral, and hip
fractures for up to 8 years. Currently available combinations of estrogens with
selective estrogen receptor modulators moderately increase BMD without causing
the extra-skeletal adverse effects of each compound alone. The cathepsin K
inhibitor odanacatib has recently been shown to decrease vertebral,
non-vertebral, and hip fracture rates and is nearing approval. Romosozumab, an
anti-sclerosin antibody, and abaloparatide, a PTH-related peptide analog, are at
present in advanced stages of clinical evaluation, so far demonstrating
efficaciousness together with a favorable safety profile. Several other agents
are currently in earlier clinical and preclinical phases of development,
including dickkopf-1 antagonists, activin A antagonists, β-arrestin analogs,
calcilytics, and Src tyrosine kinase inhibitors. Romosozumab is a humanized immunoglobulin G2 monoclonal antibody that binds and
blocks the action of sclerostin, a protein secreted by the osteocyte and an
extracellular inhibitor of canonical Wnt signaling. Blockade of sclerostin
binding to low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and
LRP6) allows Wnt ligands to activate canonical Wnt signaling in bone, increasing
bone formation and decreasing bone resorption, making sclerostin an attractive
target for osteoporosis therapy. Because romosozumab is a bone-forming agent and
an activator of canonical Wnt signaling, questions have arisen regarding a
potential carcinogenic risk. Weight-of-evidence factors used in the assessment
of human carcinogenic risk of romosozumab included features of canonical Wnt
signaling, expression pattern of sclerostin, phenotype of loss-of-function
mutations in humans and mice, mode and mechanism of action of romosozumab, and
findings from romosozumab chronic toxicity studies in rats and monkeys. Although
the weight-of-evidence factors supported that romosozumab would pose a low
carcinogenic risk to humans, the carcinogenic potential of romosozumab was
assessed in a rat lifetime study. There were no romosozumab-related effects on
tumor incidence in rats. The findings of the lifetime study and the
weight-of-evidence factors collectively indicate that romosozumab administration
would not pose a carcinogenic risk to humans. Romosozumab (Romo), a humanized sclerostin antibody, is a bone-forming agent
under development for treatment of osteoporosis. To examine the effects of Romo
on bone quality, mature cynomolgus monkeys (cynos) were treated 4 months post-
ovariectomy (OVX) with vehicle, 3 mg/kg, or 30 mg/kg Romo for 12 months, or with
30 mg/kg Romo for 6 months followed by vehicle for 6 months (30/0). Serum bone
formation markers were increased by Romo during the first 6 months,
corresponding to increased cancellous, endocortical, and periosteal bone
formation in rib and iliac biopsies at months 3 and 6. Dual-energy X-ray
absorptiometry (DXA) bone mineral density (BMD) was increased by 14% to 26% at
the lumbar spine and proximal femur at month 12, corresponding to significant
increases in bone strength at 3 and 30 mg/kg in lumbar vertebral bodies and
cancellous cores, and at 30 mg/kg in the femur diaphysis and neck. Bone mass
remained positively correlated with strength at these sites, with no changes in
calculated material properties at cortical sites. These bone-quality measures
were also maintained in the 30/0 group, despite a gradual loss of accrued bone
mass. Normal bone mineralization was confirmed by histomorphometry and ash
analyses. At the radial diaphysis, a transient, reversible 2% reduction in
cortical BMD was observed with Romo at month 6, despite relative improvements in
bone mineral content (BMC). High-resolution pQCT confirmed this decline in
cortical BMD at the radial diaphysis and metaphysis in a second set of OVX cynos
administered 3 mg/kg Romo for 6 months. Radial diaphyseal strength was
maintained and metaphyseal strength improved with Romo as estimated by finite
element modeling. Decreased radial cortical BMD was a consequence of increased
intracortical remodeling, with no increase in cortical porosity. Romo resulted
in marked improvements in bone mass, architecture, and bone strength, while
maintaining bone quality in OVX cynos, supporting its bone efficacy and safety
profile. © 2016 American Society for Bone and Mineral Research. Sclerostin, a glycoprotein produced primarily by osteocytes, blocks the
canonical Wnt signaling bone formation pathway. Romosozumab is a humanized
monoclonal antibody to sclerostin that binds to sclerostin, permitting the
engagement of Wnt ligands with their co-receptors, resulting in an increase in
bone formation and bone mineral density (BMD). Clinical studies with romosozumab
have shown dramatic improvements in BMD at the spine and hip. Romosozumab is
associated with improvement in bone strength through mechanisms that include
increases in bone formation and, different from classical osteoanabolic agents,
suppression of bone resorption. Areas covered: Herein, the authors highlight the
available data on romosozumab for the treatment of osteoporosis. This includes
the latest data on the efficacy, pharmacokinetics and pharmacodynamics as well
as safety and tolerability data. Expert opinion: Monthly subcutaneous dosing of
romosozumab reduces the risk of vertebral and clinical fractures in women with
postmenopausal osteoporosis, with a favorable balance of benefits and risks.
Romosozumab is a promising emerging anabolic agent with a novel mechanism of
action that may expand the options for treating osteoporotic patients at high
risk of fracture. Treatment with sclerostin antibody (romosozumab) increases bone formation while
reducing bone resorption, leading to increases in bone volume and bone mineral
density. Sclerostin antibody treatment may also provide beneficial changes in
trabecular microarchitecture and strength that are not reflected in bone volume
and density. Here we use three-dimensional dynamic histomorphometry to determine
longitudinal changes in vertebral trabecular microarchitecture in adolescent
male cynomolgus monkeys (4-5 years old) treated with sclerostin antibody.
Animals were treated bi-weekly with either sclerostin antibody (30 mg/kg, sc,
n = 6) or vehicle (n = 6) for 10 weeks. Animals were administered fluorochrome
bone formation labels on days 14 and 24 (tetracycline) and on days 56 and 66
(calcein), followed by necropsy on day 70. Cylindrical specimens of cancellous
bone from the 5th lumbar vertebrae were used to generate high-resolution,
three-dimensional images of bone and fluorescent labels of bone formation
(0.7 × 0.7 × 5.0 µm/voxel). The three-dimensional images of the bone formation
labels were used to determine the bone volume formed between days 14 and 66 and
the resulting alterations in trabecular microarchitecture within each bone.
Treatment with sclerostin antibody resulted in a conversion of rod-like
trabeculae into plate-like trabeculae at a higher rate than in vehicle-treated
animals (p = 0.01). Plate bone volume fraction was greater in the sclerostin
antibody group relative to vehicle (mean 43 vs. 30%, p < 0.05). Bone formation
increased the thickness of trabeculae in all three trabecular orientations
(axial, oblique, and transverse, p < 0.05). The volume of bone formed between
days 14 to 66 was greater in sclerostin antibody-treated groups (9.0 vs. 5.4%,
p = 0.02), and new bone formation due to sclerostin antibody treatment was
associated with increased apparent stiffness as determined from finite element
models. Our results demonstrate that increased bone formation associated with
sclerostin antibody treatment increases plate-like trabecular morphology and
improves mechanical performance. Increased understanding of bone biology has led to the discovery of several
unique signaling pathways that regulate bone formation and resorption. The Wnt
signaling pathway plays a significant role in skeletal development, adult
skeletal homeostasis, and bone remodeling. Sclerostin is an inhibitor of the Wnt
signaling pathway. Romosozumab, a humanized monoclonal antibody that binds to
sclerostin, prevents sclerostin from exerting this inhibitory effect. Therefore,
in the presence of romosozumab, the Wnt signaling pathway is activated leading
to bone formation and bone mineral density gain. Clinical studies of romosozumab
have shown that this agent is one of the most potent bone anabolic agents in
development to date. Romosozumab does not act solely as an anabolic agent, but
rather, it has effects on increasing bone formation as well as reducing bone
resorption. In the clinical studies, patients tolerated romosozumab well with no
major safety signals reported. In a Phase III study, romosozumab as compared to
placebo has been shown to reduce vertebral fractures by 73% after 1 year of
treatment. Sequential therapy with romosozumab for 1 year followed by denosumab
in the second year reduced vertebral fractures by 75% as compared to the group
that received placebo for 1 year and denosumab in the second year. Romosozumab
holds significant potential, by a novel mechanism of action, to expand our
ability to treat osteoporosis. More studies are needed to determine the ideal
setting in which romosozumab may be used to optimize osteoporosis treatment. There has been substantial progress in the management of patients with
osteoporosis and the prevention of osteoporotic fractures. Currently available
strong anti-resorptive agents are bisphosphonates and an anti-receptor activator
of nuclear factor-kappa B ligand (RANKL) antibody, denosumab. Although
bisphosphonates and denosumab both inhibit bone resorption and prevent vertebral
and non-vertebral fractures, their mechanisms of action are different. Whereas
bisphosphonates' effects on bone mineral density and fracture peak around 3 to 5
years and become plateaued, those of denosumab are maintained for up to 10
years. There are differences in the modes of action of these two drugs.
Bisphosphonates accumulate on the mineralized bone surface and are released by
the acid environment under osteoclastic bone resorption, whereas denosumab is
not accumulated on bone but directly binds RANKL and inhibits its binding to the
receptor RANK. Thus, the reduction in denosumab concentration 4 to 6 months
after injection may enable RANK to bind to RANKL, where it is highly expressed,
such as in damaged bone regions. As anabolic agents, only teriparatide has been
available for a long time, but abaloparatide, a synthetic analog of PTHrP(1-34),
is currently under development. Because of the difference in the preferential
binding conformations of PTH1 receptor between teriparatide and abaloparatide,
the latter shows anabolic effects with fewer bone resorptive effects.
Romosozumab, an anti-sclerostin antibody, inhibits the action of sclerostin, a
canonical Wnt signal inhibitor secreted from osteocytes, and enhances canonical
Wnt signaling. Romosozumab robustly increases vertebral and proximal femoral
bone mineral density within 12 months and inhibits vertebral and clinical
fractures in patients with osteoporosis by enhancing bone formation and
inhibiting bone resorption. In this review, we summarize the recent advances in
therapeutic agents for the treatment of osteoporosis and discuss future
prospects with their use. |
Which proteins are regulated by Nrf2? | Keap1-Nrf2 system is known as a sensor of electrophilic compounds, and protects cells from oxidative stress through induction of various antioxidant enzymes. | Cellular stress leads to an upregulation of gene transcription. We asked if
there is a specificity in the activation of the stress-responsive transcription
factors Nrf2, ATF4, and AP-1/c-Jun, or if activation of these proteins is a
redundant cellular answer toward extracellular stressors. Here, we show that
oxidative stress, induced by stimulation of the cells with the oxidant arsenite,
strongly activated gene transcription via the stress-responsive element (StRE),
while phorbol ester or tunicamycin, activators of AP-1/c-Jun or ATF4,
respectively, activated AP-1 or nutrient-sensing response element-mediated
transcription. Preincubation of the cells with N-acetyl-cysteine or
overexpression of thioredoxin selectively attenuated arsenite-induced
upregulation of StRE-regulated transcription. Expression of either
domit-negative or constitutively active mutants of Nrf2, ATF4, or c-Jun
confirmed that distinct transcription units are regulated by these transcription
factors. Physiological stimuli involving the activation of either Gαq-coupled
designer receptors or the protein kinases c-Jun N-terminal protein kinase or p38
strongly stimulated transcription via AP-1/c-Jun, with minimal effects on Nrf2
or ATF4-responsive promoters. Thus, activation of transcription by extracellular
signaling molecules shows specificity at the level of the chemical nature of the
signaling molecule, at the level of the intracellular transduction process, and
at the level of signal-responsive transcription factors. J. Cell. Biochem. 118:
127-140, 2017. © 2016 Wiley Periodicals, Inc. AIMS: The NLRP3 inflammasome is a multiprotein complex that protects hosts
against a variety of pathogens. However, the molecular mechanisms of modulating
NLRP3 inflammasome activation, especially at the priming step, are still poorly
understood. This study was designed to elucidate the negative regulation of
nuclear factor E2-related factor-2 (Nrf2) on the activation of NLRP3
inflammasome.
RESULTS: We reported that Nrf2 activation inhibited NLRP3 expression, caspase-1
cleavage, and subsequent IL-1β generation. Compared with normal cells,
Nrf2-deficient cells showed upregulated cleaved caspase-1, which were attributed
to the increased transcription of NLRP3 caused by excess reactive oxygen species
(ROS). Furthermore, priming of the NLRP3 inflammasome was sensitive to the
exogenous ROS levels induced by H2O2 or rotenone. Combined with adenosine
triphosphate, rotenone triggered higher activity of the NLRP3 inflammasome
compared with lipopolysaccharide, suggesting that ROS promoted the priming step.
In addition, Nrf2-induced NQO1 was involved in the inhibition of the NLRP3
inflammasome. In an in vivo alum-induced peritonitis mouse model, Nrf2
activation suppressed typical IL-1 signaling-dependent inflammation, whereas
Nrf2-/- mice exhibited a significant increase in the recruitment of immune cell
and the generation of IL-1β compared with wild-type mice.
INNOVATION: We elucidated the effects and possible mechanisms of Nrf2
activation-induced NQO1 expression on NLRP3 inflammasome inactivation and
established a novel regulatory role of the Nrf2 pathway in ROS-induced NLRP3
priming.
CONCLUSIONS: We demonstrated Nrf2 negatively regulating NLRP3 inflammasome
activity by inhibiting the priming step and suggested that Nrf2 could be a
potential target for some uncontrolled inflammasome activation-associated
diseases. Antioxid. Redox Signal. 26, 28-43. |
What drug cures hepatitis C? | Sofosbuvir-based therapy cures hepatitis C virus infection | BACKGROUND: The introduction of innovative specialty pharmaceuticals with high
prices has renewed efforts by public and private healthcare payers to constrain
their utilization, increase patient cost-sharing, and compel government
intervention on pricing. These efforts, although rational for individual payers,
have the potential to undermine the public health impact and overall economic
value of these innovations for society. The emerging archetypal example is the
outcry over the cost of sofosbuvir, a drug proved to cure hepatitis C infection
at a cost of $84,000 per person for a course of treatment (or $1000 per tablet).
This represents a radical medical breakthrough for public health, with great
promise for the long-term costs associated with this disease, but with major
short-term cost implications for the budgets of healthcare payers.
OBJECTIVES: To propose potential ficing models to provide a workable and
lasting solution that directly addresses the misalignment of incentives between
healthcare payers confronted with the high upfront costs of innovative specialty
drugs and the rest of the US healthcare system, and to articulate these in the
context of the historic struggle over paying for innovation.
DISCUSSION: We describe 3 innovative ficing models to manage expensive
specialty drugs that will significantly reduce the direct, immediate cost burden
of these drugs to public and private healthcare payers. The 3 ficing models
include high-cost drug mortgages, high-cost drugs reinsurance, and high-cost
drug patient rebates. These models have been proved successful in other areas
and should be adopted into healthcare to mitigate the high-cost of specialty
drugs. We discuss the distribution of this burden over time and across the
healthcare system, and we match the ficial burden of medical innovations to
the healthcare stakeholders who capture their overall value. All 3 models work
within or replicate the current healthcare marketplace mechanisms for
distributing immediate high-cost events across multiple at-risk stakeholders,
and/or encouraging active participation by patients as consumers.
CONCLUSION: The adoption of these 3 models for the ficing of high-cost drugs
would ameliorate decades-long economic conflict in the healthcare system over
the value of, and ficial responsibility for, drug innovation. |
Is there any role of interleukin-11 in cardiovascular fibrosis? | Yes. Interleukin 11 (IL11) upregulation is the dominant transcriptional response to TGFB1 exposure and required for its profibrotic effect. IL11 and its receptor (IL11RA) are expressed specifically in fibroblasts where they drive non-canonical, ERK-dependent autocrine signalling that is required for fibrogenic protein synthesis. In mice, fibroblast-specific Il11 transgene expression or Il11 injection causes heart and kidney fibrosis and organ failure whereas genetic deletion of Il11ra1 is protective against disease. Thus, inhibition of IL11 prevents fibroblast activation across organs and species in response to a range of important pro-fibrotic stimuli. | Author information:
(1)National Heart Centre Singapore, Singapore.
(2)Duke-National University of Singapore Medical School, Singapore.
(3)Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115,
USA.
(4)Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular
Medicine in the Helmholtz Association (MDC), Robert-Rossle Strasse 10, 13125
Berlin, Germany.
(5)Inflammation Division, Walter and Eliza Hall Institute of Medical Research,
Parkville, Victoria 3052, Australia.
(6)Department of Medical Biology, The University of Melbourne, Parkville,
Victoria 3050, Australia.
(7)Skaggs School of Pharmacy and Pharmaceutical Sciences, University of
California San Diego, La Jolla, California, USA.
(8)Department of Medicine, University of California at San Diego, La Jolla,
California 92093, USA.
(9)Department of Pharmacology, University of California at San Diego, La Jolla,
California 92093, USA.
(10)Kandang Kerbau Women's and Children's Hospital, Singapore.
(11)Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston,
Massachusettes 02115, USA.
(12)Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA.
(13)DZHK (German Centre for Cardiovascular Research), partner site, Berlin,
Germany.
(14)Charité-Universitätsmedizin, Berlin, Germany.
(15)Berlin Institute of Health (BIH), Berlin, Germany.
(16)National Heart and Lung Institute, Imperial College London, London, UK.
(17)MRC-London Institute of Medical Sciences, Hammersmith Hospital Campus, Du
Cane Road, London, W12 0NN, UK. |
List major risk factors for Alzheimer's disease. | Apolipoprotein E4
type 2 diabetes
Clusterin
Hypertension
advancing age
obesity | The incidence of Alzheimer's disease (AD) is increasing. Major risk factors for
AD are advancing age and diabetes. Lately, obesity has been associated with an
increased risk of dementia. Obese and diabetic individuals are prone to
decreased circulating levels of zinc, reducing the amount of zinc available for
crucial intracellular processes. In the brain, zinc co-localizes with glutamate
in synaptic vesicles, and modulates NMDA receptor activity. Intracellular zinc
is involved in apoptosis and fluctuations in cytoplasmic Zn(2+) affect
modulation of intracellular signaling. The ZNT and ZIP proteins participate in
intracellular zinc homeostasis. Altered expression of zinc-regulatory proteins
has been described in AD patients. Using microarray data from human frontal
cortex (BrainCloud), this study investigates expression of the SCLA30A (ZNT) and
SCLA39A (ZIP) families of genes in a Caucasian and African-American sample of
145 neurologically and psychiatrically normal individuals. Expression of ZNT3
and ZNT4 were significantly reduced with increasing age, whereas expression of
ZIP1, ZIP9 and ZIP13 were significantly increased. Increasing body mass index
(BMI) correlated with a significant reduction in ZNT1 expression similar to what
is seen in the early stages of AD. Increasing BMI also correlated with reduced
expression of ZNT6. In conclusion, we found that the expression of genes that
regulate intracellular zinc homeostasis in the human frontal cortex is altered
with increasing age and affected by increasing BMI. With the increasing rates of
obesity throughout the world, these findings warrant continuous scrutiny of the
long-term consequences of obesity on brain function and the development of
neurodegenerative diseases. Progressive accumulation of amyloid-β peptide (Aβ) in the brain is implicated as
the central event in the development of Alzheimer's disease (AD). It is thought
that extracellular Aβ triggers toxic signals leading to neurodegeneration. The
events downstream of Aβ however are not entirely clear. Clusterin (Apo J) is one
of the major risk factors for sporadic form of AD. Clusterin binds to Aβ and
prevents Aβ aggregation. In addition, clusterin promotes Aβ degradation and
accelerates Aβ clearance from the brain. Clusterin thus protects neurons from Aβ
and loss of clusterin level in the brain is implicated as promoting AD
pathology. In this study, we found that the level of clusterin protein but not
mRNA is reduced in the brains of 3xTg-AD mice. When rat hippocampal primary
neurons were treated with Aβ1-42, level of clusterin protein but not mRNA was
downregulated. Aβ1-42-induced downregulation of clusterin was blocked by
lysosome inhibitors bafilomycin A1 and ammonium chloride. In neurons, Aβ1-42
induced expression of sortilin, a lysosomal sorting protein that targets
proteins to lysosome for degradation. In BE(2) M17 human neuroblastoma cells,
clusterin bound to sortilin and when sortilin expression was silenced,
Aβ1-42-induced clusterin downregulation was almost completely blocked. Our data
demonstrate that in neurons, Aβ1-42 promotes lysosomal degradation of clusterin
by inducing expression of sortilin and provide a novel mechanism by which Aβ
promotes AD pathogenesis. Hypertension is one of the major risk factors for central nervous system (CNS)
disorders like stroke and Alzheimer's disease (AD). On the other hand, CNS
diseases like AD have been associated with gliosis and impaired neurogenesis.
Further, renin angiotensin system (RAS) is intricately associated with
hypertension; however, the accumulating evidences suggest that over-activity of
RAS may perpetuate the brain inflammation related with AD. Therefore, in the
present study, we examined the effect of hypertension and RAS on glial
(astrocytes and microglia) activation and hippocampal neurogenesis in a rat
model of chronic hypertension. We used Candesartan [angiotensin type 1 receptor
(AT1R) blocker (ARB)] both at a low dose (0.1 mg/kg) and anti-hypertensive dose
(2 mg/kg) to explore whether their effect on astrocyte and microglial
activation, neuroinflammation, and neurogenesis is blood pressure (BP) dependent
or independent. Our data revealed that hypertension induces robust microglial
and astrocyte activation, neuroinflammation, and cripples hippocampal
neurogenesis. Importantly, AT1R blockade by Candesartan, even at low dose
(0.1 mg/kg), prevented astrocyte and microglial activation and neuroinflammation
in the brain of hypertensive rats. Mechanistically, AT1R blockade prevented the
activation of NADPH oxidase, reactive oxygen species (ROS) generation,
suppression of MAP kinase and NFкB signaling. Importantly, we, for the first
time to our knowledge, provided the evidence that AT1R blockade by activating
Wnt/β-catenin signaling, promotes neurogenesis during hypertensive state. We
conclude that AT1R blockade prevents astrocyte and microglial activation and
improves hippocampal neurogenesis in hypertensive state, independent of BP
lowering action. |
What can be predicted with the Wells criteria? | Wells criteria are used to determine clinical probability of pulmonary embolism. | STUDY OBJECTIVE: The literature suggests that the d -dimer is useful in patients
suspected of having pulmonary embolism and who have a low pretest probability of
disease. A previously defined clinical decision rule, the Wells Criteria, may
provide a reliable and reproducible means of determining this pretest
probability. We evaluate the interrater agreement and external validity of Wells
Criteria in determining pretest probability in patients suspected of having
pulmonary embolism.
METHODS: This was a prospective observational study. Trained research assistants
enrolled patients during 120 random 8-hour shifts. Patients who underwent
imaging for pulmonary embolism after a medical history, physical examination,
and chest radiograph were enrolled. Treating providers and research assistants
determined pretest probability according to Wells Criteria in a blinded fashion.
Two d -dimer assays were run. Three-month follow-up for the diagnosis of
pulmonary embolism was performed. Interrater agreement tables were created.
kappa Values, sensitivities, and specificities were determined.
RESULTS: Of the 153 eligible patients, 3 patients were missed, 16 patients
declined, and 134 (88%) patients were enrolled. Sixteen (12%) patients were
diagnosed with pulmonary embolism. The kappa values for Wells Criteria were 0.54
and 0.72 for the trichotomized and dichotomized scorings, respectively. When
Wells Criteria were trichotomized into low pretest probability (n=59, 44%),
moderate pretest probability (n=61, 46%), or high pretest probability (n=14,
10%), the pulmonary embolism prevalence was 2%, 15%, and 43%, respectively. When
Wells Criteria were dichotomized into pulmonary embolism-unlikely (n=88, 66%) or
pulmonary embolism-likely (n=46, 34%), the prevalence was 3% and 28%,
respectively. The immunoturbidimetric and rapid enzyme-linked immunosorbent
assay d -dimer assays had similar sensitivities (94%) and specificities (45%
versus 46%).
CONCLUSION: Wells Criteria have a moderate to substantial interrater agreement
and reliably risk stratify pretest probability in patients with suspected
pulmonary embolism. BACKGROUND AND AIMS: Determining clinical probability of pulmonary embolism (PE)
with Wells scoring system is the first step towards diagnosis of PE. Definitive
diagnosis of PE is confirmed by computed tomography pulmonary angiography
(CTPA).
METHODS: This was a prospective study on 80 patients referred to the Institute
for Pulmonary Diseases of Vojvodina with suspected PE between April 2010 and
August 2012. Clinical probability of PE was determined according to the Wells
and modified Wells scoring system. CTPA was performed in 60 patients. The degree
of pulmonary vascular obstruction was quantified by the Qanadli index.
RESULTS: Low clinical probability of PE was present in one patient (1.6%),
moderate in 43 (71.6%) and high in 16 (26.6%) patients. PE was confirmed in 50
(83.3%) patients. There were 21 patients (42%) whose Quanadli index was <25%, 18
(36%) between 25%-50%, while Quanadli index was ≥50 in 11 patients (22%). When
compared to CTPA findings, modified Wells scoring system showed 90% sensitivity
[95% confidence interval (CI) 78.2%-96.6%], and 20% specificity (95% CI
3.11%-55.6%), positive predictive value (PPV) 84.9% (95% CI 72.4%-93.2%) and
negative predictive value (NPV) 28.6% (95% CI 4.5%-70.7%). There was weak
positive correlation between Wells score and Quanadli index (r = 0.14;
P = 0.29), without statistical significance. Wells score was significantly
higher in haemodynamically unstable than in haemodynamically stable patients
(6.8 vs 5.6, P = 0.014). There was no statistically significant difference
between the values of Quanadli index in these two groups (31.33% vs 26.64%,
P = 0.062).
CONCLUSION: Modified Wells criteria have high sensitivity but low specificity in
PE diagnostics. The Wells score does not correlate well with the Quanadli index. ESSENTIALS: When high probability of pulmonary embolism (PE), sensitivity of
computed tomography (CT) is unclear. We investigated the sensitivity of
multidetector CT among 134 patients with a high probability of PE. A normal CT
alone may not safely exclude PE in patients with a high clinical pretest
probability. In patients with no clear alternative diagnosis after CTPA, further
testing should be strongly considered.
BACKGROUND: Whether patients with a negative multidetector computed tomographic
pulmonary angiography (CTPA) result and a high clinical pretest probability of
pulmonary embolism (PE) should be further investigated is controversial.
METHODS: This was a prospective investigation of the sensitivity of
multidetector CTPA among patients with a priori clinical assessment of a high
probability of PE according to the Wells criteria. Among patients with a
negative CTPA result, the diagnosis of PE required at least one of the following
conditions: ventilation/perfusion lung scan showing a high probability of PE in
a patient with no history of PE, abnormal findings on venous ultrasonography in
a patient without previous deep vein thrombosis at that site, or the occurrence
of venous thromboembolism (VTE) in a 3-month follow-up period after
anticoagulation was withheld because of a negative multidetector CTPA result.
RESULTS: We identified 498 patients with a priori clinical assessment of a high
probability of PE and a completed CTPA study. CTPA excluded PE in 134 patients;
in these patients, the pooled incidence of VTE was 5.2% (seven of 134 patients;
95% confidence interval [CI] 1.5-9.0). Five patients had VTEs that were
confirmed by an additional imaging test despite a negative CTPA result (five of
48 patients; 10.4%; 95% CI 1.8-19.1), and two patients had objectively confirmed
VTEs that occurred during clinical follow-up of at least 3 months (two of 86
patients; 2.3%; 95% CI 0-5.5). None of the patients had a fatal PE during
follow-up.
CONCLUSIONS: A normal multidetector CTPA result alone may not safely exclude PE
in patients with a high clinical pretest probability. Purpose To determine the frequency of, and yield after, provider overrides of
evidence-based clinical decision support (CDS) for ordering computed tomographic
(CT) pulmonary angiography in the emergency department (ED). Materials and
Methods This HIPAA-compliant, institutional review board-approved study was
performed at a tertiary care, academic medical center ED with approximately 60
000 annual visits and included all patients who were suspected of having
pulmonary embolism (PE) and who underwent CT pulmonary angiography between
January 1, 2011, and August 31, 2013. The requirement to obtain informed consent
was waived. Each CT order for pulmonary angiography was exposed to CDS on the
basis of the Wells criteria. For patients with a Wells score of 4 or less, CDS
alerts suggested d-dimer testing because acute PE is highly unlikely in these
patients if d-dimer levels are normal. The yield of CT pulmonary angiography
(number of positive PE diagnoses/total number of CT pulmonary angiographic
examinations) was compared in patients in whom providers overrode CDS alerts (by
performing CT pulmonary angiography in patients with a Wells score ≤4 and a
normal d-dimer level or no d-dimer testing) (override group) and those in whom
providers followed Wells criteria (CT pulmonary angiography only in patients
with Wells score >4 or ≤4 with elevated d-dimer level) (adherent group). A
validated natural language processing tool identified positive PE diagnoses,
with subsegmental and/or indeterminate diagnoses removed by means of chart
review. Statistical analysis was performed with the χ2 test, the Student t test,
and logistic regression. Results Among 2993 CT pulmonary angiography studies in
2655 patients, 563 examinations had a Wells score of 4 or less but did not
undergo d-dimer testing and 26 had a Wells score of 4 or less and had normal
d-dimer levels. The yield of CT pulmonary angiography was 4.2% in the override
group (25 of 589 studies, none with a normal d-dimer level) and 11.2% in the
adherent group (270 of 2404 studies) (P < .001). After adjustment for the risk
factor differences between the two groups, the odds of an acute PE finding were
51.3% lower when providers overrode alerts than when they followed CDS
guidelines. Comparison of the two groups including only patients unlikely to
have PE led to similar results. Conclusion The odds of an acute PE finding in
the ED when providers adhered to evidence presented in CDS were nearly double
those seen when providers overrode CDS alerts. Most overrides were due to the
lack of d-dimer testing in patients unlikely to have PE. © RSNA, 2016. OBJECTIVE: Our objective was to evaluate the diagnostic value of computed
tomography angiography (CTA) and ventilation perfusion (V/Q) scan in the
assessment of pulmonary embolism (PE) by means of a Bayesian statistical model.
METHODS: Wells criteria defined pretest probability. Sensitivity and specificity
of CTA and V/Q scan for PE were derived from pooled meta-analysis data.
Likelihood ratios calculated for CTA and V/Q were inserted in the nomogram.
Absolute (ADG) and relative diagnostic gains (RDG) were analyzed comparing post-
and pretest probability. Comparative gain difference was calculated for CTA ADG
over V/Q scan integrating ANOVA p value set at 0.05.
RESULTS: The sensitivity for CT was 86.0% (95% CI: 80.2%, 92.1%) and specificity
of 93.7% (95% CI: 91.1%, 96.3%). The V/Q scan yielded a sensitivity of 96% (95%
CI: 95%, 97%) and a specificity of 97% (95% CI: 96%, 98%). Bayes nomogram
results for CTA were low risk and yielded a posttest probability of 71.1%, an
ADG of 56.1%, and an RDG of 374%, moderate-risk posttest probability was 85.1%,
an ADG of 56.1%, and an RDG of 193.4%, and high-risk posttest probability was
95.2%, an ADG of 36.2%, and an RDG of 61.35%. The comparative gain difference
for low-risk population was 46.1%; in moderate-risk 41.6%; and in high-risk a
22.1% superiority. ANOVA analysis for LR+ and LR- showed no significant
difference (p = 0.8745, p = 0.9841 respectively).
CONCLUSIONS: This Bayesian model demonstrated a superiority of CTA when compared
to V/Q scan for the diagnosis of pulmonary embolism. Low-risk patients are
recognized to have a superior overall comparative gain favoring CTA. Role of prophylactic anticoagulation in acutely ill medical patients has been
extensively probed with the development of guidelines which made it convenient
for the physicians to adopt a particular anticoagulation regimen for
thromboprophylaxis. Intermingled with the guidelines are the development of
modern anticoagulants like direct factor Xa inhibitors which are being studied
for their role in the prevention of venous thromboembolism (VTE) in medically
ill patients and have been concluded so far with the positive note. We are going
to discuss a case of a patient who was admitted in the medical ICU with hospital
acquired pneumonia. As her immediate risk of VTE was low (Wells criteria), she
was advised mechanical measures to prevent VTE along with continuation of
rivaroxaban therapy which had already been prescribed for her avalvular atrial
fibrillation. While mechanically ventilated, she developed pulmonary venous
thromboembolism. It is the first case report of VTE in adequately anticoagulated
patient with rivaroxaban. OBJECTIVE: Determine effects of evidence-based clinical decision support (CDS)
on the use and yield of computed tomographic pulmonary angiography for suspected
pulmonary embolism (CTPE) in Emergency Department (ED) patients.
METHODS: This multi-site prospective quality improvement intervention conducted
in three urban EDs used a pre/post design. For ED patients aged 18+years with
suspected PE, CTPE use and yield were compared 19months pre- and 32months
post-implementation of CDS intervention based on the Wells criteria, provided at
the time of CTPE order, deployed in April 2012. Primary outcome was the yield
(percentage of studies positive for acute PE). Secondary outcome was utilization
(number of studies/100 ED visits) of CTPE. Chi-square and statistical process
control chart assessed pre- and post-intervention differences. An interrupted
time series analysis was also performed.
RESULTS: Of 558,795 patients presenting October 2010-December 2014, 7987 (1.4%)
underwent CTPE (mean age 52±17.5years, 66% female, 60.1% black); 34.7% of
patients presented pre- and 65.3% post-CDS implementation. Overall CTPE
diagnostic yield was 9.8% (779/7987 studies positive for PE). Yield increased a
relative 30.8% after CDS implementation (8.1% vs. 10.6%; p=0.0003). There was no
statistically significant change in CTPE utilization (1.4% pre- vs. 1.4%
post-implementation; p=0.25). A statistical process control chart demonstrated
immediate and sustained improvement in CTPE yield post-implementation.
Interrupted time series analysis demonstrated the slope of PE findings versus
time to be unchanged before and after the intervention (p=0.9). However, there
was a trend that the intervention was associated with a 50% increased
probability of PE finding (p=0.08), suggesting an immediate rather than gradual
change after the intervention.
CONCLUSIONS: Implementing evidence-based CDS in the ED was associated with an
immediate, significant and sustained increase in CTPE yield without a measurable
decrease in CTPE utilization. Further studies will be needed to assess whether
stronger interventions could further improve appropriate use of CTPE. |
What is the purpose of the Tabix tool? | Tabix is the first generic tool that indexes position sorted files in TAB-delimited formats such as GFF, BED, PSL, SAM and SQL export, and quickly retrieves features overlapping specified regions. Tabix features include few seek function calls per query, data compression with gzip compatibility and direct FTP/HTTP access. Tabix is implemented as a free command-line tool as well as a library in C, Java, Perl and Python. It is particularly useful for manually examining local genomic features on the command line and enables genome viewers to support huge data files and remote custom tracks over networks. | |
What is MULTOVL? | MULTOVL is an application suite that detects and statistically analyses multiple overlaps of genomic regions in a fast and efficient manner. The package supports the detection of multiple region intersections, unions and 'solitary' genomic regions. The significance of actually observed overlaps is estimated by comparing them with empirical null distributions generated by random shuffling of the input regions. | We present the MULTOVL application suite that detects and statistically analyses
multiple overlaps of genomic regions in a fast and efficient manner. The package
supports the detection of multiple region intersections, unions and 'solitary'
genomic regions. The significance of actually observed overlaps is estimated by
comparing them with empirical null distributions generated by random shuffling
of the input regions. |
How is Hsd17b1 associated with endometriosis? | Evidence for association between the Ser312Gly polymorphism in HSD17B1 and endometriosis was found in a Japanese population. The A-allele of HSD17B1 appears to confer higher risk for endometriosis. Inhibition of the estradiol-synthesizing enzyme 17beta-hydroxysteroid dehydrogenase type 1 (17beta-HSD1) has been proposed as a promising new therapeutic option to treat estrogen-dependent diseases like endometriosis | BACKGROUND: Endometriosis, an estrogen-dependent disease, is believed to be
influenced by multiple genetic and environmental factors. Here, we evaluated
whether the risk and severity of endometriosis are associated with polymorphisms
in estradiol-synthesizing enzyme genes: the Ser312Gly polymorphism in
17-beta-hydroxysteroid dehydrogenase type 1 (HSD17B1) and the Arg264Cys
polymorphism in cytochrome P450, subfamily XIX (CYP19).
METHODS: All participants underwent diagnostic laparoscopy, and the stage of
endometriosis was determined according to the Revised American Fertility Society
classification. Of the 138 women enrolled, 59 had no endometriosis, 21 had stage
I, 10 had stage II, 23 had stage III and 25 had stage IV. SNPs were
discriminated by allele-specific oligonucleotide hybridization.
RESULTS: Individuals having at least one A-allele (A/G or A/A genotype) of
HSD17B1 showed a significantly increased risk of endometriosis (A/G genotype:
adjusted OR, 3.06; 95%CI 1.21-7.74; A/A genotype: adjusted OR, 3.02; 95%CI
1.08-8.43). There was a significant trend associating A/G + A/A genotypes with
severity of endometriosis (P for trend < 0.01). No statistically significant
association was found for the CYP19 polymorphism.
CONCLUSIONS: Evidence for association between the Ser312Gly polymorphism in
HSD17B1 and endometriosis was found in a Japanese population. The A-allele of
HSD17B1 appears to confer higher risk for endometriosis. Lowering local estradiol concentration by inhibition of the
estradiol-synthesizing enzyme 17beta-hydroxysteroid dehydrogenase type 1
(17beta-HSD1) has been proposed as a promising new therapeutic option to treat
estrogen-dependent diseases like endometriosis and breast cancer. Based on a
molecular modelling approach we designed and synthesized novel C15-substituted
estrone derivatives. Subsequent biological evaluation revealed that potent
inhibitors of human 17beta-HSD1 can be identified in this compound class. The
best, compound 21, inhibited recombit human 17beta-HSD1 with an IC50 of 10nM
and had no effect on the activity of recombit human 17beta-hydroxysteroid
dehydrogenase type 2 (17beta-HSD2), the enzyme catalyzing estradiol
inactivation. These properties were retained in a cell-based enzyme activity
assays. In spite of the estrogen backbone compound 21 did not show estrogen
receptor mediated effects in vitro or in vivo. In conclusion, estrone C15
derivative compound 21 can be regarded as a promising lead compound for further
development as a 17beta-HSD1 inhibitor. |
What is the drug Tecfidera used against? | Tecifidera is approved for the treatment of relapsing-remitting multiple sclerosis. | OBJECTIVE: To describe the clinical evidence supporting the safety, efficacy,
and clinical utility of oral dimethyl fumarate for the treatment of multiple
sclerosis (MS).
DATA SOURCES: A comprehensive PubMed search was conducted in July 2013 using the
search terms dimethyl fumarate and Tecfidera. Reference lists of abstracted
publications were reviewed to identify relevant works that were not retrieved
via the electronic search. Additional information was obtained from the FDA Web
site, manufacturer prescribing information, and Clinicaltrials.gov.
STUDY SELECTION AND DATA ABSTRACTION: Clinical trials and review articles that
included the use of dimethyl fumarate in the treatment of MS and were available
in English were abstracted for review.
DATA SYNTHESIS: The safety and efficacy of dimethyl fumarate for the treatment
of relapsing remitting MS was confirmed in 2 phase III trials, DEFINE and
CONFIRM. Relative to placebo, twice-daily dimethyl fumarate was found to reduce
the proportion of patients with relapses at 2 years by 34% to 49% and the
annualized relapse rate by 44% to 53%. Although the incidence of serious adverse
effects did not differ from that of placebo, intolerable flushing and
gastrointestinal adverse effects prompted discontinuation in 3% and 4% of
patients, respectively.
CONCLUSIONS: In March 2013, dimethyl fumarate was approved as a third oral
option for patients with relapsing forms of MS. Although no head-to-head trials
have been conducted, a comparison of data from phase III trials suggests that
the efficacy of dimethyl fumarate is comparable to that of existing oral agents
and may offer a preferable safety profile. As a case study of patent coverage for a repurposed drug, Biogen Idec's approach
for Tecfidera(®), an oral formulation of dimethyl fumarate, was analyzed. While
mixtures of fumarates have been used for over 50 years to treat psoriasis,
Tecifidera is approved for the treatment of relapsing-remitting multiple
sclerosis. Biogen pursued claims to pharmaceutical formulations and useful doses
for treating multiple sclerosis, an approach that is relevant to pharmaceutical
lifecycle management in general. A survey of recent US, EP, and PCT patent
applications indicate other companies are developing competing fumarate
formulations. While it is possible to pursue secondary patents for compounds
without composition of matter coverage, regulatory data exclusivity provides
additional protection to delay competitors. |
Is there a disease or condition called Exploding Head Syndrome? | Exploding head syndrome (EHS) is characterized by loud noises or a sense of explosion in the head during sleep transitions. | Attention has recently been drawn to a condition termed the exploding head
syndrome, which is characterized by unpleasant, even terrifying sensations of
flashing lights and/or sounds during reported sleep. Nine patients complaining
of sensations of explosions in the head during sleep or drowsiness were
investigated with polysomnographic recordings. None of them had any neurological
disorder. Five patients reported explosions during the recording sessions.
According to the recordings, the attacks always took place when the patients
were awake and relaxed. In two cases abrupt electroencephalographic (EEG) and
electromyographic changes indicating increasing alertness were recorded at the
time of the reported attacks. In the remaining three cases no EEG changes were
seen. Thus, there were no indications of an epileptic etiology to the condition.
In all patients the symptoms ameliorated spontaneously with time. The severity
of the symptoms was reduced by reassurance of the harmlessness of the condition.
Clomipramine was prescribed to three patients who all reported immediate relief
of symptoms. It is concluded that symptoms of this type are probably not true
hypnagogic phenomena but may be an expression of emotional stress in the awake
state. The case is reported of a 47-year old female suffering from the exploding head
syndrome. This syndrome consists of a sudden awakening due to a loud noise
shortly after falling asleep, sometimes accompanied by a flash of light. The
patient is anxious and experiences palpitations and excessive sweating. Most
patients are more than fifty years of age. Further investigations do not reveal
any abnormality. The pathogenesis is unknown, and no therapy other than
reassurance is necessary. Fifty patients suffering from the "exploding head syndrome" are described. This
hitherto unreported syndrome is characterised by a sense of an explosive noise
in the head usually in the twilight stage of sleep. The associated symptoms are
varied, but the benign nature of the condition is emphasised and neither
extensive investigation nor treatment are indicated. This article reviews the features of an uncommon malady termed "the exploding
head syndrome." Sufferers describe terrorizing attacks of a painless explosion
within their head. Attacks tend to occur at the onset of sleep. The etiology of
attacks is unknown, although they are considered to be benign. Treatment with
clomipramine has been suggested, although most sufferers require only
reassurance that the spells are benign in nature. Exploding head syndrome is a rare phenomenon but can be a significant disruption
to quality of life. We describe a 39-year-old female with symptoms of a loud
bang and buzz at sleep onset for 3 years. EEG monitoring confirmed these events
occurred in transition from stage 1 sleep. This patient reported improvement in
intensity of events with topiramate medication. Based on these results,
topiramate may be an alternative method to reduce the intensity of events in
exploding head syndrome. INTRODUCTION: Exploding head syndrome (EHS) is a rare parasomnia in which
affected individuals awaken from sleep with the sensation of a loud bang. The
etiology is unknown, but other conditions including primary and secondary
headache disorders and nocturnal seizures need to be excluded.
CASE PRESENTATION: A 57-year-old Indian male presented with four separate
episodes of awakening from sleep at night after hearing a flashing sound on the
right side of his head over the last 2 years. These events were described 'as if
there are explosions in my head'. A neurologic examination, imaging studies, and
a polysomnogram ensued, and the results led to the diagnosis of EHS.
CONCLUSION: EHS is a benign, uncommon, predominately nocturnal disorder that is
self-limited. No treatment is generally required. Reassurance to the patient is
often all that is needed. Exploding head syndrome is characterized by the perception of abrupt, loud
noises when going to sleep or waking up. They are usually painless, but
associated with fear and distress. In spite of the fact that its characteristic
symptomatology was first described approximately 150 y ago, exploding head
syndrome has received relatively little empirical and clinical attention.
Therefore, a comprehensive review of the scientific literature using Medline,
PsycINFO, Google Scholar, and PubMed was undertaken. After first discussing the
history, prevalence, and associated features, the available polysomnography data
and five main etiological theories for exploding head syndrome are summarized.
None of these theories has yet reached domice in the field. Next, the various
methods used to assess and treat exploding head syndrome are discussed, as well
as the limited outcome data. Finally, recommendations for future measure
construction, treatment options, and differential diagnosis are provided. BACKGROUND: Exploding head syndrome (EHS) is characterized by attacks of a
sudden noise or explosive feeling experienced in the head occurring during the
transition from wake to sleep or from sleep to wake.
METHODS: We present six new cases extending the clinical experience with the
syndrome. We also reviewed all available cases from the scientific literature
and evaluated the typical features of EHS.
RESULTS: The female to male ratio is 1.5 to 1. The median age at onset is 54. In
average, one attack per day to one attack per week occurs. Some patients suffer
from several attacks per night. In about half of all patients, a chronic time
course can be observed but episodic or sporadic occurrence is also common. The
most frequent accompanying symptoms beside the noise are fear and flashes of
light. Polysomnographic studies do not reveal any specific sleep pattern
associated with EHS. Tricyclic antidepressants are helpful in some patients.
However, most patients do not need treatment because of the benign nature of the
syndrome.
CONCLUSION: EHS is a well-defined disease entity with a benign nature. Exploding head syndrome is characterized by the perception of loud noises during
sleep-wake or wake-sleep transitions. Although episodes by themselves are
relatively harmless, it is a frightening phenomenon that may result in clinical
consequences. At present there are little systematic data on exploding head
syndrome, and prevalence rates are unknown. It has been hypothesized to be rare
and to occur primarily in older (i.e. 50+ years) individuals, females, and those
suffering from isolated sleep paralysis. In order to test these hypotheses, 211
undergraduate students were assessed for both exploding head syndrome and
isolated sleep paralysis using semi-structured diagnostic interviews: 18.00% of
the sample experienced lifetime exploding head syndrome, this reduced to 16.60%
for recurrent cases. Though not more common in females, it was found in 36.89%
of those diagnosed with isolated sleep paralysis. Exploding head syndrome
episodes were accompanied by clinically significant levels of fear, and a
minority (2.80%) experienced it to such a degree that it was associated with
clinically significant distress and/or impairment. Contrary to some earlier
theorizing, exploding head syndrome was found to be a relatively common
experience in younger individuals. Given the potential clinical impacts, it is
recommended that it be assessed more regularly in research and clinical
settings. PURPOSE OF REVIEW: The medical aphorism that common things happen commonly makes
unique (and less common) migraine subtypes especially appropriate to review for
the general neurologist. This article also identifies some rare headache
disorders and other disturbances, and offers strategies to manage them.
RECENT FINDINGS: This article discusses migraine with brainstem aura, which is
troublesome clinically and has had a change in terminology in the International
Classification of Headache Disorders, Third Edition, beta version (ICHD-3 beta),
and hemiplegic migraine, which is also troublesome in practice. The rare
headache disorder hypnic headache and the exploding head syndrome are also
discussed. When hypnic headache is recognized, it is eminently treatable, while
exploding head syndrome is a benign condition with no reported consequences.
SUMMARY: Unique migraine subtypes, rare headache disorders, and other
disturbances present to neurologists. When recognized, they can often be managed
very well, which offers significant benefits to patients and practice
satisfaction to neurologists. Background Exploding head syndrome (EHS) is characterized by loud noises or a
sense of explosion in the head during sleep transitions. Though relatively
common, little is known about its characteristic symptoms or associated
features. Methods A cross-sectional study of 49 undergraduates with EHS was
performed. A clinical interview established diagnosis. Results The most common
accompanying symptoms were tachycardia, fear, and muscle jerks/twitches with the
most severe associated with respiration difficulties. Visual phenomena were more
common than expected (27%). EHS episodes were perceived as having a random
course, but were most likely to occur during wake-sleep transitions and when
sleeping in a supine position. Only 11% reported EHS to a professional, and 8%
of those with recurrent EHS attempted to prevent episodes. Conclusions EHS
episodes are complex (Mean (M) = 4.5 additional symptoms), often multisensorial,
and usually associated with clinically-significant fear. They are rarely
reported to professionals and treatment approaches are limited. Diagnosis of paroxysmal events in epilepsy patients is often made through
video-telemetry electroencephalography in the epilepsy monitoring unit. This
case report describes the first-ever diagnosis of exploding head syndrome in a
patient with longstanding epilepsy and novel nocturnal events. In this report,
we describe the presentation of exploding head syndrome and its prevalence and
risk factors. In addition, the prevalence of newly diagnosed sleep disorders
through video-telemetry electroencephalography in the epilepsy monitoring unit
is briefly reviewed. This report also illustrates the novel use of clobazam for
the treatment of exploding head syndrome. |
What is INCB3619? | INCB3619, is avselective, potent, orally bioavailable small-molecule inhibitor of a subset of ADAM proteases that prevents the processing and activation of multiple ErbB ligands, including heregulin. In addition, INCB3619 inhibits gefitinib-resistant HER3 signaling and enhances gefitinib inhibition of EGFR signaling in NSCLC. Administration of INCB3619 to tumor-bearing mice reduced ErbB ligand shedding in vivo and inhibited ErbB pathway signaling (e.g., phosphorylation of Akt), tumor cell proliferation, and survival. | We describe here the existence of a heregulin-HER3 autocrine loop, and the
contribution of heregulin-dependent, HER2-mediated HER3 activation to gefitinib
insensitivity in non-small cell lung cancer (NSCLC). ADAM17 protein, a major
ErbB ligand sheddase, is upregulated in NSCLC and is required not only for
heregulin-dependent HER3 signaling, but also for EGFR ligand-dependent signaling
in NSCLC cell lines. A selective ADAM inhibitor, INCB3619, prevents the
processing and activation of multiple ErbB ligands, including heregulin. In
addition, INCB3619 inhibits gefitinib-resistant HER3 signaling and enhances
gefitinib inhibition of EGFR signaling in NSCLC. These results show that ADAM
inhibition affects multiple ErbB pathways in NSCLC and thus offers an excellent
opportunity for pharmacological intervention, either alone or in combination
with other drugs. PURPOSE: ErbB receptor signaling pathways are important regulators of cell fate,
and their dysregulation, through (epi)genetic alterations, plays an etiologic
role in multiple cancers. ErbB ligands are synthesized as membrane-bound
precursors that are cleaved by members of the ADAM family of zinc-dependent
metalloproteases. This processing, termed ectodomain shedding, is essential for
the functional activation of ErbB ligands. Recent studies suggest that elevated
levels of ErbB ligands may circumvent the effectiveness of ErbB-targeted
therapeutics. Here, we describe the discovery and preclinical development of
potent, selective inhibitors of ErbB ligand shedding.
EXPERIMENTAL DESIGN: A series of biochemical and cell-based assays were
established to identify selective inhibitors of ErbB ligand shedding. The
therapeutic potential of these compounds was assessed in multiple in vivo models
of cancer and matrix metalloprotease-related toxicity.
RESULTS: INCB3619 was identified as a representative selective, potent, orally
bioavailable small-molecule inhibitor of a subset of ADAM proteases that block
shedding of ErbB ligands. Administration of INCB3619 to tumor-bearing mice
reduced ErbB ligand shedding in vivo and inhibited ErbB pathway signaling (e.g.,
phosphorylation of Akt), tumor cell proliferation, and survival. Further,
INCB3619 synergized with clinically relevant cancer therapeutics and showed no
overt or compounding toxicities, including fibroplasia, the dose-limiting
toxicity associated with broad-spectrum matrix metalloprotease inhibitors.
CONCLUSIONS: Inhibition of ErbB ligand shedding offers a potentially novel and
well-tolerated therapeutic strategy for the treatment of human cancers and is
currently being evaluated in the clinic. |
What is crenezumab? | Crenezumab is a humanized antibody targeting Amyloid-β (Aβ) which is currently tested in multiple clinical trials for the prevention of Alzheimer's disease. It strongly reacts with amyloid plaques and detects N-terminally modified Aβ peptides Aβ4-42 and pyroglutamate Aβ3-42. | |
Describe Vanishing lung syndrome. | Vanishing lung syndrome, also known as idiopathic giant bullous emphysema, is a rare disease characterized by giant emphysematous bullae. It is a rare radiological syndrome in which the lungs appear to be disappearing on X-ray. It typically occurs in young, thin male smokers with large bullae in one or more upper lobes occupying at least one-third of the hemithorax. This syndrome is associated with significant morbidity and mortality. | PURPOSE: we reviewed the imaging findings in 7 patients with idiopathic giant
bullous emphysema. This is a chronic, progressive condition usually affecting
young male smokers and is characterized by giant emphysematous bullae, which
commonly develop in the upper lobes. Extensive paraseptal emphysema coalesces to
form giant bullae, compressing the normal lung parenchyma and often displacing
it centrally. These bullae occupy at least one-third of a hemithorax.
MATERIALS AND METHODS: Seven patients with chest radiographic evidence of a
bulla or bullae occupying at least one-third of a hemithorax, who had also been
examined with high-resolution computed tomography (HRCT), were included in this
retrospective study. On HRCT scans, the size, location, and distribution of the
bullae were documented and categorized as either subpleural or central.
RESULTS: The HRCT scan findings in all 7 study patients included numerous bullae
ranging in size from a few centimeters in diameter to giant bullae nearly
filling an entire hemithorax, mimicking a pneumothorax. Five of the 7 patients
had extensive upper lobe predomit bullae, 4 of the 7 patients showed severe
bilateral disease with asymmetric involvement, 2 of the 7 patients demonstrated
left lung predomice and whereas 1 patient showed right lung predomit
disease. All of our patients had subpleural bullae, had parenchymal fibrosis,
another had extensive subcutaneous emphysema, and 1 had accompanying
bronchiectasis.
CONCLUSIONS: The predomit findings on HRCT scans are extensive paraseptal
emphysema coalescing into giant bullae. HRCT is helpful in confirming the
diagnosis of VLS, assessing the degree of the disease, and providing information
to guide treatment. Vanishing lung syndrome (VLS) is a rare and distinct clinical syndrome that
usually affects young men. VLS leads to severe progressive dyspnea and is
characterized by extensive, asymmetric, peripheral, and predomitly upper lobe
giant lung bullae. Case reports have suggested an additive role of marijuana use
in the development of this disease in young male tobacco smokers. We herein
report a case of a 65-year-old Hispanic male previously diagnosed with severe
emphysema and acquired immune deficiency syndrome (AIDS), with a history of
intravenous heroin use and active marijuana smoking who presents to the
emergency department with severe progressive shortness of breath he was found to
have multiple large subpleural bullae occupying more than one-third of the
hemithorax on chest computerized tomography (CT), characteristic of vanishing
lung syndrome. The patient was mechanically ventilated and later developed a
pneumothorax requiring chest tube placement and referral for surgical
bullectomy. Surgical bullectomy has shown high success rates in alleviating the
debilitating symptoms and preventing the life threatening complications of this
rare syndrome. This case further emphasizes the importance of recognizing VLS in
patients with severe emphysema and heavy marijuana smoking. Giant bullous emphysema (GBE), known as 'vanishing lung syndrome', usually
occurs in association with chronic obstructive pulmonary disease (COPD). In this
report, we describe a patient with giant emphysematous bulla occupying
approximately 95% of the right hemithorax, who had history of repeated attacks
of acute exacerbation of COPD. About 95% of right pulmonary parenchyma was
removed. Delightfully, the 5% of residual lung compressed for 4 years gradually
inflated, and occupied the whole hemithorax. Preoperatively he was functionally
and clinically severely disabled while improved markedly after bullectomy. Vanishing lung syndrome, also known as idiopathic giant bullous emphysema, is a
rare disease characterized by giant emphysematous bullae. The disease is
diagnosed by radiological findings of giant bullae in one, or both, of the upper
lobes of the lung, occupying at least one-third of the hemithorax. There have
been several reports of vanishing lung syndrome, however it remains to be
determined whether genetic inheritance is associated with the disease. In the
present study, five patients within one family, with vanishing lung syndrome,
were reported during a follow-up period of ~ 20 years. All of the patients were
diagnosed by radiological findings, which showed diffuse bullae in the lungs,
which were of varying size and asymmetrical distribution, and the occurrence of
pneumothorax or emphysema. The Medical Ethics Committee of the People's Hospital
of Zhangye Municipality (Zhangye, China) approved this study, and all subjects
gave their informed consent During the follow-up period of 20 years, bullae in
these patients were shown to progressively increase, and no other pulmonary
diseases, including lung cancer, tuberculosis, pneumoconiosis and chronic
bronchitis were observed. Autosomal domit inheritance was observed in five
cases, and autosomal recessive inheritance was observed in one case. The present
study suggests that vanishing lung syndrome may be associated with autosomal
domit and recessive genetic inheritance. Vanishing lung syndrome (VLS) is a rare radiological syndrome in which the lungs
appear to be disappearing on X-ray. It is a chronic, progressive condition
usually affecting young male smokers and is characterised by giant emphysematous
bullae, which commonly develop in the upper lobes. We describe here a rare case
of 60-year-old male patient who had a history of chronic smoking for 30 years.
He had been admitted in the hospital multiple times due to spontaneous
pneumothorax, type 2 respiratory failure and infective exacerbations. He was
earlier diagnosed having chronic obstructive pulmonary disease (COPD) with
predomit emphysema on the basis of his history and chest X-ray findings.
Eventually, his CT chest revealed the diagnosis of giant bullous
disease/vanishing lung syndrome. He had been surviving with his little lung
tissue for about 10 years. No such case has been reported in the literature so
far. He was attended last on 12th October, 2009 in medical outdoor of Christian
Medical College and Hospital, Ludhiana by the first three authors. Thereafter,
the patient was not traceable. Giant bullous emphysema, or vanishing lung syndrome, typically occurs in young,
thin male smokers with large bullae in one or more upper lobes occupying at
least one-third of the hemithorax. We present here a rare case of giant bullous
emphysema in a mid-age nonsmoking female who was seen for progressive shortness
of breath and cough. Chest computed tomography found a giant bulla in the middle
lobe of right lung. The patient underwent successful thoracoscopic bullectomy
and is currently without residual symptoms. Giant bullae often mimic pneumothorax on radiographic appearance. We present the
case of a 55-year-old man admitted to a referring hospital with dyspnea, cough,
and increasing sputum production; he refused thoracotomy for tension
pneumothorax and presented to our hospital for a second opinion. A computed
tomography (CT) scan at our hospital revealed a giant bulla, which was managed
conservatively as an exacerbation of chronic obstructive pulmonary disease.
Thoracic surgery was consulted but advised against bullectomy. Giant bullae can
easily be misdiagnosed as a pneumothorax, but the management of the two
conditions is vastly different. Distinguishing between the two may require CT
scan. Symptomatic giant bullae are managed surgically. We highlight the
etiology, presentation, diagnosis, and treatment of bullous lung disease,
especially in comparison to pneumothorax. Vanishing lung syndrome is a clinical presentation of giant bullous emphysema
associated with significant morbidity and mortality. We present a case of a
50-year-old white woman with vanishing lung syndrome who presented with a
spontaneous secondary pneumothorax and an uncontrolled bronchopleural fistula.
The large bronchopleural fistula was initially controlled with a double-lumen
endotracheal tube and a tube thoracostomy. After surgical efforts failed,
complete left lung isolation was performed with multiple intrabronchial valves.
In essence, a medical pneumonectomy was performed. The patient was weaned from
mechanical ventilation and discharged to rehabilitation. She was ambulatory at
5-month follow-up. Marijuana use has been increasing across the United States due to its
legalization as both a medicinal and recreational product. A small number of
case reports have described a pathological entity called vanishing lung syndrome
(VLS), which is a rare bullous lung disease usually caused by tobacco smoking.
Recent case reports have implicated marijuana in the development of VLS. We
present a case of a 47-year-old man, who presented to our hospital with
shortness of breath, fevers and a productive cough. On physical exam, he was
tachypneic with audible stridor and absent right sided breath sounds.
Laryngoscopy showed a retropharyngeal abscess, and chest radiography showed a
possible right pneumothorax. Chest computed tomography (CT) showed bilateral
bullous emphysematous lung disease with a giant bulla occupying most of his
right lung field. He was placed on mechanical ventilation and treated with broad
spectrum antibiotics in the intensive care unit, where he developed acute
respiratory distress syndrome (ARDS). He continued to decline, and developed
disseminated intravascular coagulation, after which he succumbed to his disease. |
What do the trispecific HIV antibodies target? | Trispecific HIV antibodies (Abs) allow a single molecule to interact with three independent HIV-1 envelope determinants: the CD4 binding site, the membrane-proximal external region (MPER), and the V1V2 glycan site. | |
What is calciphylaxis | Calcific uraemic arteriolopathy also known as calciphylaxis is an unusual and potentially fatal condition characterised by small-vessel calcification and ischaemic skin necrosis. | OBJECTIVE: Calciphylaxis, a rare disorder typically affecting renal failure
patients, results in vascular calcification with subsequent skin necrosis,
gangrene, and often death from sepsis. Parathyroid hormone is thought to act as
a tissue sensitizer leading to these soft tissue changes. As such,
parathyroidectomy is often advocated to control this complicated condition. A
discussion of calciphylaxis does not exist in the otolaryngology literature, and
head and neck surgeons performing parathyroidectomy should be aware of this
phenomenon. This study evaluates the success of parathyroidectomy in reversing
the ill effects of calciphylaxis in both our patient population and the
literature.
STUDY DESIGN: Retrospective study and review of the literature.
METHODS: Five patients with calciphylaxis treated at our institution were
evaluated for mortality, surgical and perioperative complications, wound
healing, and predictors of patient outcomes.
RESULTS: Two patients died from sepsis and infectious complications of their
calciphylaxis shortly after surgery. Of the three survivors, two later died (15
and 18 mo after surgery) from causes not directly related to calciphylaxis. The
other long-term survivor required partial amputation of a leg for osteomyelitis.
There was one operative complication-- wound infection requiring antibiotic
therapy, drainage, and packing. Postoperative hypocalcemia required treatment in
two patients. Immediate perioperative survival was more likely in patients with
leukocyte counts less than 20,000 cells/mL.
CONCLUSIONS: Calciphylaxis is a serious disease and patients often succumb to
sepsis and infectious complications. Patients with extremely high leukocyte
counts from coexistent infections may have a worse prognosis. Although a
conclusive effective therapy does not exist, parathyroidectomy can be safely
performed and may benefit some patients with what is often an otherwise fatal
disease. The literature to date generally confirms our findings. Key Words:
Calciphylaxis, parathyroid hormone, parathyroidectomy, skin necrosis, chronic
renal failure. We report a patient with severe bilateral leg ulceration that was resistant to
treatment. A biopsy confirmed the cause as calciphylaxis. Calciphylaxis refers
to a syndrome of calcium deposition in the small and intermediate dermal
vasculature which can lead to epidermal ischaemia, ulceration and necrosis. Most
cases occur in those with chronic renal failure and secondary
hyperparathyroidism. We describe the rare presentation of calciphylaxis in a
patient with normal renal function and primary hyperparathyroidism who had many
classical features. Unfortunately she developed gangrene, sepsis and died. Calciphylaxis is a severe complication of chronic renal failure, confined almost
exclusively to patients on dialysis therapy. Histological characteristics of
calciphylaxis include small-vessel calcifications of skin, subcutaneous tissue,
and visceral organs. These vascular changes promote tissue ischemia that often
results in tissue necrosis. In this study, we investigated the extent of skin
ischemia in patients with calciphylaxis by means of transcutaneous oxygen
tension (TCPO(2)) measurement, a noninvasive test that accurately assesses skin
oxygenation. TCPO(2) levels were measured in 21 patients with calciphylaxis and
21 age- and sex-matched patients without evidence of calciphylaxis (controls).
TCPO(2) levels were measured bilaterally at the chest, anterior abdomen, and
upper thigh while patients breathed room air and after a 30-minute exposure to
100% fraction of inspired oxygen (FIO(2)). Compared with controls, patients with
calciphylaxis showed significantly lower TCPO(2) levels at each body region. In
both controls and patients with calciphylaxis, lower TCPO(2) levels correlated
with increased weight and use of hemodialysis. No correlation with serum
parathyroid hormone (PTH), serum calcium, or serum phosphorus values was
present, although 39% of the patients with calciphylaxis had markedly elevated
PTH values (sixfold greater than normal; >300 pg/dL). Low TCPO(2) levels in
patients with calciphylaxis were documented in body regions with and without
skin lesions. In patients with calciphylaxis, extremely low TCPO(2) values
(</=30 mm Hg while patients breathed room air) were present in 62% of the body
regions with skin lesions and 26% of the body regions without lesions. Room-air
TCPO(2) levels </=30 mm Hg were present in only 0.8% of the body regions of
control patients. TCPO(2) levels obtained while patients breathed 100% FIO(2)
remained lower in patients with calciphylaxis than in controls. In conclusion,
TCPO(2) levels are abnormally low in patients with calciphylaxis, indicating
that severe and diffuse skin ischemia exists, even at areas free of skin
lesions. Low TCPO(2) values did not substantially increase with 100% FIO(2) in
many patients with calciphylaxis, suggesting a fixed insufficiency of the skin
vessels. This study shows that TCPO(2) measurements may allow rapid and
noninvasive screening for skin ischemia before the development of skin lesions
in patients with calciphylaxis. Calcific uraemic arteriolopathy, also named calciphylaxis, is a rare but serious
disorder characterized by medial mural calcification of small vessel leading to
tissue ischaemia. It most commonly occurs in end stage renal disease patients on
dialysis or recently received renal transplant with chronic nephropathy
allograft. The pathogenesis of calciphylaxis is poorly understood. Abnormalities
in mineral metabolism are clearly involved, but the specific factors that
induces this disorder are not completely known.
OBJECTIVES: Describe the main clinical features, outcomes and follow up of all
calciphylaxis cases recorded in our dialysis unit in order to analyse the
incidence, the main biologic parameters and the therapeutic background in which
calciphylaxis appeared.
MATERIAL AND METHODS: We performed a descriptive study about all the
calciphylaxis cases diagnosed at our dialysis unit between the years 1991 and
2005.
RESULTS: 8 cases, 6 women. Mean age: 65.3 years. All the patients were on
haemodialysis treatment (one previous renal transplant). Mean time on dialysis
was 76.6 months. Cumulative incidence was 1.17%. The principal end stage renal
disease aethiology was neprhoangioeslerosis in four patients. Secondary
hiperparatyrhoidism was present in 4 patients and 2 of them had been
paratyrhoidectomized previously. A second cutaneous biopsy was needed for
correct diagnosis in 3 patients. Calciphylaxis distal lesions were present in 7
patients. Two cases required urgent paratyrhoidectomy in order to control
calciphylaxis. Only in 2 cases a Ca x P product > 60 mg/dL was present and 3
cases had PTHi values higher than 300 pg/mL. Calcium phosphate binders and
vitamin D were present in 2 and 4 cases, respectively. One patient with proximal
calciphylaxis died due to skin injury infection.
CONCLUSIONS: Calciphylaxis is a rare disorder but not exceptional, related to
end stage renal disease patients. The diagnosis requires a high clinical
suspicion, being sometimes difficult to distinguish from other entities in spite
of pathological study. Proximal distribution of calciphylaxis had worst
prognostic. Metabolic disorders and therapeutics background were not different
from other patients included in dialysis treatment. BACKGROUND AND OBJECTIVES: Calciphylaxis, or calcific uremic arteriolopathy, is
a well-described entity in end-stage kidney disease and renal transplant
patients; however, little systematic information is available on calciphylaxis
from nonuremic causes. This systematic review was designed to characterize
etiologies, clinical features, laboratory abnormalities, and prognosis of
nonuremic calciphylaxis.
DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A systematic review of literature
for case reports and case series of nonuremic calciphylaxis was performed. Cases
included met the operational definition of nonuremic
calciphylaxis-histopathologic diagnosis of calciphylaxis in the absence of
end-stage kidney disease, renal transplantation, or acute kidney injury
requiring renal replacement therapy.
RESULTS: We found 36 cases (75% women, 63% Caucasian, aged 15 to 82 yr) of
nonuremic calciphylaxis. Primary hyperparathyroidism, maligcy, alcoholic
liver disease, and connective tissue disease were the most common reported
causes. Preceding corticosteroid use was reported for 61% patients. Protein C
and S deficiencies were seen in 11% of patients. Skin lesions were
morphologically similar to calcific uremic arteriolopathy. Mortality rate was
52%, with sepsis being the leading cause of death.
CONCLUSION: Calciphylaxis should be considered while evaluating skin lesions in
patients with predisposing conditions even in the absence of end-stage kidney
disease and renal transplantation. Nonuremic calciphylaxis is reported most
often in white women. Mineral abnormalities that are invoked as potential causes
in calcific uremic arteriolopathy are often absent, suggesting that
heterogeneous mechanisms may contribute to its pathogenesis. Nonuremic
calciphylaxis is associated with high mortality, and there is no known effective
treatment. Calciphylaxis is a rare complication that occurs in 1% of patients with
end-stage renal disease (ESRD) each year. Extensive microvascular calcification
and occlusion/thrombosis lead to violaceous skin lesions, which progress to
nonhealing ulcers with secondary infection, often leading to sepsis and death.
The lower extremities are predomitly involved (roughly 90% of patients).
Although most calciphylaxis patients have abnormalities of the calcium-phosphate
axis or elevated levels of parathyroid hormone, these abnormalities do not
appear to be fundamental to the pathophysiology of the disorder. We report on a
case of histologically proven calciphylaxis in a 54-year-old woman with normal
renal function and normal calcium-parathyroid homeostasis. She had a history of
alcoholic cardiomyopathy, and was treated with warfarin anticoagulation. She has
been successfully treated with antibiotics, i.v. biophosphonates and intensive
local wound care. We recorded a complete wound healing in contrast to what is
reported in other series. Calciphylaxis is a disease in which metastatic calcification affects small- and
medium-sized vessels resulting in significant dermatologic manifestations.
Lesions typically occur over areas of high fat content and progress to black
leathery eschars. Calciphylaxis is associated with intense pain and markedly
increased risk of infection, often leading to sepsis requiring hospitalization.
Diagnosis is made by clinical history and skin biopsy. Management of
calciphylaxis is interdisciplinary, emphasizing factors such as primary
prevention, proper wound care, pain control, and hormone and mineral balance.
Although calciphylaxis carries a high mortality rate, symptomatic treatment has
shown promise as a method for controlling disease progression. Calciphylaxis is a rare condition characterized by medial calcification of
small- and medium-sized vessels that subsequently leads to ischemic necrosis.
Calciphylaxis most often occurs in patients with end-stage renal disease and
secondary hyperparathyroidism. We present a unique case of calciphylaxis in
which the patient did not have end-stage renal disease. Instead, primary
hyperparathyroidism and/or alcoholic cirrhosis were the more likely causes of
her calciphylaxis. In addition, our case demonstrated not only calciphylaxis but
also fragmentation and calcification of elastic fibers within the dermis,
changes that are most often seen in pseudoxanthoma elasticum. This is the first
reported case of calciphylaxis, to our knowledge, with histopathologic changes
of pseudoxanthoma elasticum in a patient who is nonuremic. Calciphylaxis is a metastatic calcification-induced vasculopathy that results in
the occlusion of small blood vessels. Although calciphylaxis is normally
associated with end-stage renal disease, calciphylaxis from non-uremic origin
occurs as well. While the number of reports continues to increase, a standard
treatment for non-uremic calciphylaxis has yet to be established. Sodium
thiosulfate (STS), which has been proven to be effective in the treatment of
uremic calciphylaxis, shows promise; however, reports of its use in non-uremic
cases are limited. We describe a case of non-uremic calciphylaxis in a patient
with normal renal and parathyroid function who had complete resolution of
disease after treatment with STS, and we review similar cases in the published
work. Based on the successful outcomes detailed in this case series, STS appears
to be an effective therapy for non-uremic calciphylaxis. BACKGROUND: Calciphylaxis combines features of vascular thrombotic occlusion and
endoluminal calcification. In this study we examine the expression of
osteopontin as a diagnostic marker and its role in lesional pathogenesis.
METHODS: 25 formalin-fixed, paraffin embedded skin biopsies of 20 females and 5
males (mean age of 60 years) with a diagnosis of calciphylaxis were assessed for
osteopontin expression.
RESULTS: Lower extremities were the most commonly involved areas; however a
truncal and genital distribution was also noted in 3 cases. Renal failure was
present in 21 of 25 cases. One patient had myeloproliferative disorder and one
patient had advanced colon cancer. The domit pathology was localized to the
subcutaneous fat, characterized by mural calcification and luminal thrombosis
affecting capillaries, venules, arterioles and small arteries. In 2 cases, a
subcutaneous thrombogenic vasculopathy without calcification was noted.
Osteopontin expression was confined to the subcutis, being most striking in
calcified vessels but also apparent in vessels without calcification, including
mineral poor variants of calciphylaxis.
CONCLUSION: Calciphylaxis represents a unique calcific thrombogenic
vasculopathy, not limited to renal failure. Ectopic osteopontin expression may
define a critical and initial event in the calciphylaxis pathogenesis.
Therapeutic agents designed to reduce osteopontin expression may be of value in
its treatment. Calciphylaxis is characterized by calcification in the medium and small vessel
arterioles and can be a life-threatening complication often associated with
chronic kidney disease (CKD). A review of the literature was conducted to
explore existing evidence about the relationship between obesity and
calciphylaxis. A total of 54 publications (published between 1962 and 2015) were
identified. Most studies noted a variety of risk factors for calciphylaxis,
including CKD, female gender, Caucasian race, liver disease, and lower serum
albumin. Obesity was identified as a risk factor in 6 of the 8 studies reviewed.
In one study, obesity was found to increase the risk of calciphylaxis 4-fold.
The majority of calciphylaxis lesions in obese persons were proximal in
distribution; all studies report proximal lesions are associated with a higher
mortality rate than distal lesions. The mortality rate of persons with CKD and
calciphylaxis is 8 times higher than that of persons with CKD without
calciphylaxis. There is no definitive evidence to support the belief current
epidemic rates of obesity, diabetes, (diabesity), and chronic renal disease will
predispose more patients to the development of calciphylaxis. However, until
more information from the calciphylaxis registries and other studies is
available, clinicians should maintain a high index of suspicion when a patient
presents with indurated, painful nodules or necrotic ulcers, especially if the
patient also has CKD. Calciphylaxis is a small vessel vasculopathy, characterized by medial wall
calcification that develops in a few patients with chronic renal failure. The
prognosis of skin calciphylaxis has improved considerably since the introduction
of sodium thiosulfate (STS), but it remains unclear whether this therapy is
effective against organ lesions related to calciphylaxis. Pulmonary
calciphylaxis is a usually fatal medical condition that may occur in association
with skin involvement in patients with end-stage renal disease.We report here
the case of a 49-year-old woman homozygous sickle cell disease patient on
chronic hemodialysis with biopsy-proven systemic calciphylaxis involving the
lungs and skin. On admission, ulcerative skin lesions on the lower limbs and
bilateral pulmonary infiltrates on chest computerized tomography scan were the
main clinical and radiological findings. Skin and bronchial biopsies
demonstrated calciphylaxis lesions. The intravenous administration of STS in
association with cinacalcet for 8 consecutive months led to a clear improvement
in skin lesions and thoracic lesions on chest computerized tomography scan.This
case suggests for the first time that organ lesions related to calciphylaxis,
and particularly lung injury, are potentially reversible. This improvement
probably resulted from the combination of 3 interventions (more frequent
dialysis, cinacalcet, and STS), rather than the administration of STS alone. BACKGROUND: Calcific uraemic arteriolopathy (CUA, calciphylaxis) is a rare
disease predomitly in dialysis patients and associated with high mortality.
Painful skin ulcerations and calcification of cutaneous arterioles characterize
calciphylaxis.
METHODS: We established an observational, Internet-based registry allowing
online notification for all German CUA cases. The registry recorded data about
patient characteristics, biochemistry and therapies. Blood samples were stored
in a central biobank.
RESULTS: Between 2006 and 2015, 253 CUA patients were recorded: median age 70
[interquartile range (IQR) 61-76] years, 60% females and 86% ( n = 207) dialysis
patients, translating into an estimated annual incidence rate of 0.04% in German
dialysis patients. Fifty-two per cent received vitamin K antagonists (VKAs)
prior to CUA. Skin lesions were localized in 71% on the legs or gluteal region.
In dialysis CUA patients median total serum calcium was 2.20 (IQR 2.06-2.37)
mmol/L, phosphorus 1.67 (IQR 1.35-2.03) mmol/L, intact parathyroid hormone 147
(IQR 72-276) pg/mL and fetuin-A 0.21 (IQR 0.16-0.26) g/L (normal range
0.35-0.95). Median sclerostin, osteoprotegerin, TRAP5b, bone-specific alkaline
phosphatase and c-terminal FGF23 levels were all elevated. The most frequently
recorded therapeutic procedures in dialysis CUA patients were as follows: wound
debridement (29% of cases), stopping VKA (25%), lowering calcium supply (24%),
sodium thiosulphate (22%), application of vitamin K (18%), increase of dialysis
duration/frequency (17%) and stoping active vitamin D (16%).
CONCLUSIONS: Approximately 50% of CUA patients used VKA. Our data suggest that
uncontrolled hyperparathyroidism is not the key determit of calciphylaxis.
Therapeutic strategies were heterogeneous. The experience of the German registry
will help substantially to initiate a large-scale multinational CUA registry. BACKGROUND: Calciphylaxis is a syndrome consisting of vascular calcification,
thrombosis, and skin necrosis. The syndrome develops often in chronic
hemodialysis patients. However, there have been several case reports on
calciphylaxis in patients with POEMS (polyneuropathy, organomegaly,
endocrinopathy, M-protein, and skin changes) syndrome, a systemic disease
associated with plasma cell dyscrasia and upregulation of vascular endothelial
growth factor (VEGF).
METHODS: In 76 POEMS patients and 86 age- and gender-matched disease controls,
we studied abnormal small vessel calcification by computed tomography (CT) of
the soft tissues. Clinical and laboratory profiles were compared between POEMS
patients with and without calciphylaxis. Histological examination was performed
in six autopsy cases.
RESULTS: Small vessel calcification on CT was found in 17 % of POEMS patients
and in none of the controls (P < 0.001). Autopsy confirmed calciphylaxis in 2
(33 %) patients. Among POEMS patients, higher disease activity, including more
severe neuropathy and ascites, higher serum levels of interleukin-6, and lower
serum albumin levels, was associated with the development of calciphylaxis.
Serum levels of creatinine, calcium, and phosphate were not related to the
presence of calciphylaxis.
CONCLUSIONS: Calciphylaxis is often present in patients with POEMS syndrome.
Upregulation of multiple inflammatory cytokines such as VEGF and interleukin-6
may contribute to the development of calciphylaxis, by entirely different
mechanism from that in chronic dialysis. POEMS syndrome should be recognized as
a potential cause of calciphylaxis. WHAT IS KNOWN AND OBJECTIVE: Calciphylaxis is a rare and potentially
life-threatening cause of skin necrosis and is poorly recognized by clinicians
in non-uraemic patients.
CASE DESCRIPTION: We report five cases of warfarin-induced calciphylaxis in
patients with normal renal function. In four cases, sodium thiosulphate was
successfully used as a treatment. No other predisposing factors besides obesity
and warfarin were found in these patients.
WHAT IS NEW AND CONCLUSION: Previously only few cases of solely warfarin-induced
calciphylaxis have been described. Treatment with sodium thiosulphate has shown
promising results, and there is thus a need to improve the recognition of
calciphylaxis. INTRODUCTION: Patients with renal failure who are being treated with dialysis
frequently develop neuromuscular manifestations. Renal failure-associated
calciphylaxis, also termed calcific uremic arteriolopathy (CUA), is a
life-threatening condition usually observed in patients with end-stage renal
disease on chronic dialysis or after renal transplantation.
METHODS: We describe a hemodialyzed patient who presented with rapidly
progressive unexplained systemic vasculopathy, muscle atrophy, and proximal
weakness, that unexpectedly proved to be caused by calciphylaxis.
RESULTS: Quadriceps muscle biopsy disclosed diffuse vascular calcific deposits
on medium- and small-sized vessels, characteristic of CUA. Other changes
included ischemic myopathy, focal intracellular calcium accumulation within
myofibers, and calcium deposits in endomysial capillaries associated with marked
complement activation and C5b9 formation.
CONCLUSION: There are only a few descriptions of muscle involvement in the
context of CUA, a condition with a prognosis that depends on early diagnosis and
treatment. This report underscores the usefulness of muscle biopsy in the
diagnosis of systemic calciphylaxis. Muscle Nerve 56: 529-533, 2017. BACKGROUND: Calcific uraemic arteriolopathy (calciphylaxis) is an unusual and
potentially fatal condition characterised by small-vessel calcification and
ischaemic skin necrosis. It mainly affects patients with end-stage renal disease
(ESRD) on haemodialysis, but may rarely occur in the absence of ESRD in
conditions such as primary hyperparathyroidism, maligcy, alcoholic liver
disease and connective tissue disease.
METHODS: We reviewed the records of all patients diagnosed with calciphylaxis
while on renal replacement therapy at Tygerberg Hospital, Cape Town, South
Africa, between 1990 and 2014, to describe its presentation, course and final
outcome.
RESULTS: Nineteen patients developed calciphylaxis over this period. Their
median age was 34 years and 13 (68.4%) were female. Fifteen (78.9%) had received
a kidney transplant. All patients had painful skin lesions that rapidly
progressed to infarction. Small-vessel calcification was seen on skin biopsy in
13 patients. Twelve patients had hyperparathyroidism. Several of the
transplanted patients had been treated for graft rejection in the year preceding
the diagnosis. Treatment consisted of good wound care and efforts to normalise
serum calcium and phosphate levels. Five patients received an urgent
parathyroidectomy. The outcome was fatal in 17 patients, with sepsis being the
main cause of death.
CONCLUSIONS: In our patients, calciphylaxis carried a worse prognosis than
previously reported internationally. It should always be considered in the
differential diagnosis of painful skin lesions in the dialysis or transplant
patient. |
What is the alternative lengthening of telomeres? | Alternative lengthening of telomeres (ALT) is a telomerase independent telomere maintenance mechanism that occurs in ∼15% of cancers. It is proposed to occur preferentially at telomeric lagging strands leading to heterogeneous telomere lengths observed in most ALT cancers. | Alternative lengthening of telomeres (ALT) is a telomerase independent telomere
maintece mechanism that occurs in ∼15% of cancers. The potential mechanism of
ALT is homology-directed telomere synthesis, but molecular mechanisms of how ALT
maintains telomere length in human cancer is poorly understood. Here, we
generated TERC (telomerase RNA) gene knockouts in telomerase positive cell lines
that resulted in long-term surviving clones acquiring the ALT pathway but at a
very low frequency. By comparing these ALT cells with parental telomerase
positive cells, we observed that ALT cells possess excessively long telomeric
overhangs derived from telomere elongation processes that mostly occur during S
phase. ALT cells exhibited preferential elongation of the telomeric lagging
strands, whereas telomerase positive cells exhibited similar elongation between
leading and lagging strands. We propose that the ALT pathway preferentially
occurs at telomeric lagging strands leading to heterogeneous telomere lengths
observed in most ALT cancers. |
Which organ express and secretes the hormone FGF21? | Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic regulator expressed in multiple tissues including liver and adipose tissue. Although highest levels of expression are in pancreas, little is known about the function of FGF21 in this tissue. | Fibroblast growth factor 21 (FGF21) is an important endocrine metabolic
regulator expressed in multiple tissues including liver and adipose tissue.
Although highest levels of expression are in pancreas, little is known about the
function of FGF21 in this tissue. In order to understand the physiology of FGF21
in the pancreas, we analyzed its expression and regulation in both acinar and
islet tissues. We found that acinar tissue express 20-fold higher levels than
that observed in islets. We also observed that pancreatic FGF21 is nutritionally
regulated; a marked reduction in FGF21 expression was noted with fasting while
obesity is associated with 3-4 fold higher expression. Acinar and islet cells
are targets of FGF21, which when systemically administered, leads to
phosphorylation of the downstream target ERK 1/2 in about half of acinar cells
and a small subset of islet cells. Chronic, systemic FGF21 infusion
down-regulates its own expression in the pancreas. Mice lacking FGF21 develop
significant islet hyperplasia and periductal lymphocytic inflammation when fed
with a high fat obesogenic diet. Inflammatory infiltrates consist of TCRb+ Thy1+
T lymphocytes with increased levels of Foxp3+ regulatory T cells. Increased
levels of inflammatory cells were coupled with elevated expression of cytokines
such as TNFα, IFNγ and IL1β. We conclude that FGF21 acts to limit islet
hyperplasia and may also prevent pancreatic inflammation. We have previously shown that Fibroblast growth factor 21 (Fgf21) is expressed
in the thymus as well as in the liver. In line with this expression profile,
Fgf21 was recently reported to protect against ageing-related thymic senescence
by improving the function of thymic epithelial cells (TECs). However, the
function of Fgf21 in the juvenile thymus remained to be elucidated. We
investigated the physiological roles of Fgf21 in the juvenile thymus and found
that young Fgf21 knockout mice, but not β-Klotho knockout mice nor adult Fgf21
knockout mice, showed a significant reduction in the percentage of
single-positive CD4+ and CD8+ thymocytes without obvious alteration in TECs.
Furthermore, treatment with recombit FGF21 protein rescued the impairment in
fetal thymus organ culture (FTOC) of Fgf21 knockout mice. Annexin V staining
revealed FGF21 protein enhanced apoptosis of immature thymocytes undergoing
selection process in FTOC, suggesting that FGF21 may facilitate the selection of
developing T cells. Endocrine Fgf21 from the liver induced by metabolic
stimulation did not affect juvenile thymocyte development. Our data suggest that
Fgf21 acts as one of intrathymic cytokines in the neonatal and juvenile thymus,
involving thymocyte development in a β-Klotho-independent manner. |
What is the biological role of Neddylation? | NEDDylation is a post-translational protein modification that is tightly linked to ubiquitination and thereby protein degradation. It however has its own enzyme machinery. It is coupled to ubiquitination and is important for maintaining cellular homeostasis. | Genetic experiments have established an important role for the ubiquitin-like
molecule NEDD8 (neural-precursor-cell-expressed developmentally down-regulated
8) in the regulation of cell growth, viability and development. It is therefore
essential to identify the molecular targets for the pathway. Until recently, the
cullin family of proteins was characterized as the only substrates for
NEDDylation. However, through either direct biological approaches or the use of
proteomics, it is now evident that the NEDD8 proteome is more diverse than
thought previously. The present review describes the biological significance of
NEDDylation for the novel identified substrates and the emerging evidence for
the co-operation between the ubiquitin and NEDD8 pathways to control protein
function. The neddylation conjugation pathway has a pivotal role in mediating
ubiquitination of proteins and regulation of numerous biological processes.
Dysregulation in the ubiquitination and neddylation pathways is associated with
many cancers. Ubiquitination involves covalent attachment of ubiquitin to target
proteins, leading to protein degradation by the proteasome system. The activity
of the E3-ubiquitin ligase family, cullin-RING ligases, is essential for
promoting ubiquitin transfer to the appropriate substrates. Neddylation, a
process mediated by the protein NEDD8, is required for conformational changes of
cullins, a scaffolding protein situated in the core of cullin-RING ligases, and
regulation of E3 ligase activity. In this review, we present a comprehensive
discussion of the recent findings on the neddylation pathway and its importance
during tumorigenesis. The ramifications regarding the potential therapeutic use
of ubiquination and neddylation inhibition are also discussed. Posttranslational protein modifications (PTMs) are necessary for cells to
function properly. The role of PTMs in regulating immune responses, specifically
those mediated by dendritic cells (DCs), which are critical for both innate and
adaptive immunity, is not well understood. Utilizing multiple but complementary
approaches, we determined the role of an important but less understood type of
PTM, namely, neddylation, in regulating DC functions. Inhibition of neddylation
suppressed the release of proinflammatory cytokines by DCs in response to
Toll-like receptor, nucleotide oligomerization domain-like receptor, and
noninfectious CD40L stimulation. These effects were more profound than those
mediated by the proteasome inhibitor bortezomib or a commonly used
antiinflammatory agent, dexamethasone. Targeting neddylation also suppressed the
ability of DCs to stimulate murine allogeneic T cells in vitro and in vivo and
human allogeneic T-cell responses in vitro. Mechanistic studies demonstrated
that inhibition of neddylation reduced both canonical and noncanonical nuclear
factor-κB (NF-κB) activity. Neddylation inhibition prevented the degradation of
inhibitor-κB and thus reduced the translocation and activation of NF-κB, but
without perturbation of the mitogen-activated protein kinase/extracellular
signal-regulated kinase pathway. Thus, blocking neddylation could be a novel
strategy for mitigating immune-mediated disease processes. The activity of cullin-RING type ubiquitination E3 ligases is regulated by
neddylation, a process analogous to ubiquitination that culminates in covalent
attachment of the ubiquitin-like protein Nedd8 to cullins. As a component of the
E3 for neddylation, SCCRO/DCUN1D1 plays a key regulatory role in neddylation
and, consequently, cullin-RING ligase activity. The essential contribution of
SCCRO to neddylation is to promote nuclear translocation of the cullin-ROC1
complex. The presence of a myristoyl sequence in SCCRO3, one of four SCCRO
paralogues present in humans that localizes to the membrane, raises questions
about its function in neddylation. We found that although SCCRO3 binds to CAND1,
cullins, and ROC1, it does not efficiently bind to Ubc12, promote cullin
neddylation, or conform to the reaction processivity paradigms, suggesting that
SCCRO3 does not have E3 activity. Expression of SCCRO3 inhibits SCCRO-promoted
neddylation by sequestering cullins to the membrane, thereby blocking its
nuclear translocation. Moreover, SCCRO3 inhibits SCCRO transforming activity.
The inhibitory effects of SCCRO3 on SCCRO-promoted neddylation and
transformation require both an intact myristoyl sequence and PONY domain,
confirming that membrane localization and binding to cullins are required for in
vivo functions. Taken together, our findings suggest that SCCRO3 functions as a
tumor suppressor by antagonizing the neddylation activity of SCCRO. Neddylation is a post-translational protein modification that conjugates a
ubiquitin-like protein NEDD8 to target proteins. Similar to ubiquitination,
neddylation is mediated by a cascade of three NEDD8 specific enzymes, an E1
activating enzyme, an E2 conjugating enzyme and one of the several E3 ligases.
Neddylation is countered by the action of deneddylases via a process termed
deneddylation. By altering the substrate's conformation, stability, subcellular
localization or binding affinity to DNA or proteins, neddylation regulates
diverse cellular processes including the ubiquitin-proteasome system-mediated
protein degradation, protein transcription, cell signaling etc. Dysregulation of
neddylation has been linked to cancer, neurodegenerative disorders, and more
recently, cardiac disease. Here we comprehensively overview the biochemistry,
the proteome and the biological function of neddylation. We also summarize the
recent progress in revealing the physiological and pathological role of
neddylation and deneddylation in the heart. Protein neddylation, a newly characterized posttranslational modification that
adds the ubiquitin-like molecule NEDD8 to substrates, modulates important
biological processes, whereas dysfunction of neddylation may cause several
serious diseases, such as cancer. Inhibition of neddylation pathway has emerged
as a promising anticancer strategy, as evidenced by development of the
NEDD8-activating enzyme (NAE) inhibitor MLN4924. Due to its potent anti-cancer
efficacy and well-tolerated toxicity, MLN4924 has been evaluated in multiple
Phase I clinical trials for solid tumors and hematologic maligcies. Recently,
accumulating evidences indicate that neddylation pathway also plays a pivotal
role in the regulation of multiple processes of tumor microenvironment (TME),
such as tumor angiogenesis and the function of immune cells. In this review, we
briefly summarize the latest progresses in this field and highlight neddylation
pathway as an attractive therapeutic target against human cancer. Multiple strategies evolved by Mycobacterium tuberculosis (M. tb) have
contributed to its successful prevalence. We previously identified specific
genes in the cysteine protease and calcium-calmodulin pathways that regulated
immune responses from dendritic cells (DCs). In this study we have characterized
the role of neddylation in regulating various defense responses from DCs during
mycobacterial infection. Neddylation is a process that is similar to
ubiquitination. It however has its own enzyme machinery. It is coupled to
ubiquitination and is important for maintaining cellular homeostasis. Here we
show that stimulation of DCs with M. tb antigens Rv2463 and Rv3416 as well as
infection with live M. tb modulates the expression levels of key proteins in the
neddylation pathway. Further, stimulation with the two antigens promoted the
association of NEDD8 with its target Cullin-1. The modulation in the expression
levels of NEDD8 and SENtrin specific Protein 8 (SENP8) by the two antigens was
in a calcium, MAPK and TLR dependent mechanism. Further, knockdown of specific
genes of neddylation promoted the generation of oxidative burst, promoted
phagolysosome fusion in mycobacteria infected DCs and induced higher expression
of autophagy and apoptosis associated proteins in DCs. These results point
toward a unique strategy employed by mycobacteria and its antigens towards
immune suppression via modulating neddylation in DCs. Neddylation is a posttranslational modification that controls diverse biological
processes by covalently conjugating the ubiquitin-like protein NEDD8 to specific
targets. Neddylation is commonly mediated by NEDD8-specific enzymes (typical
neddylation) and, sometimes, by ubiquitin enzymes (atypical neddylation).
Although typical neddylation is known to regulate protein function in many ways,
the regulatory mechanisms and biological consequence of atypical neddylation
remain largely unexplored. Here we report that NEDD8 conjugates were accumulated
in the diseased hearts from mouse models and human patients. Proteotoxic
stresses induced typical and atypical neddylation in cardiomyocytes. Loss of
NUB1L exaggerated atypical neddylation, whereas NUB1L overexpression repressed
atypical neddylation through promoting the degradation of NEDD8. Activation of
atypical neddylation accumulated a surrogate misfolded protein, GFPu. In
contrast, suppression of atypical neddylation by NUB1L overexpression enhanced
GFPu degradation. Moreover, NUB1L depletion accumulated a cardiomyopathy-linked
misfolded protein, CryAB(R120G), whereas NUB1L overexpression promoted its
degradation through suppressing neddylation of ubiquitinated proteins in
cardiomyocytes. Consequently, NUB1L protected cells from proteotoxic
stress-induced cell injury. In summary, these data indicate that NUB1L
suppresses atypical neddylation and promotes the degradation of misfolded
proteins by the proteasome. Our findings also suggest that induction of NUB1L
could potentially become a novel therapeutic strategy for diseases with
increased proteotoxic stress. Purpose: Recent studies have shown that the process of protein neddylation was
abnormally activated in several human cancers. However, it is unknown whether
and how UBE2F, a less characterized neddylation E2, regulates lung cancer cell
survival, and whether and how NOXA, a proapoptotic protein, is ubiquitylated and
degraded by which E3 and via which ubiquitin linkage.Experimental Design:
Methods of immunohistochemistry and immunoblotting were utilized to examine
UBE2F protein expression. The biological functions of UBE2F were evaluated by in
vitro cell culture and in vivo xenograft models. The in vivo complex formation
among UBE2F-SAG-CUL5-NOXA was measured by a pulldown assay. Polyubiquitylation
of NOXA was evaluated by in vivo and in vitro ubiquitylation assays.Results:
UBE2F is overexpressed in non-small cell lung cancer (NSCLC) and predicts poor
patient survival. While UBE2F overexpression promotes lung cancer growth both in
vitro and in vivo, UBE2F knockdown selectively inhibits tumor growth. By
promoting CUL5 neddylation, UBE2F/SAG/CUL5 tri-complex activates CRL5
(Cullin-RING-ligase-5) to ubiquitylate NOXA via a novel K11, but not K48,
linkage for targeted proteasomal degradation. CRL5 inactivation or forced
expression of K11R ubiquitin mutant caused NOXA accumulation to induce
apoptosis, which is rescued by NOXA knockdown. Notably, NOXA knockdown rescues
the UBE2F silencing effect, indicating a causal role of NOXA in this process. In
lung cancer tissues, high levels of UBE2F and CUL5 correlate with a low level of
NOXA and poor patient survival.Conclusions: By ubiquitylating and degrading NOXA
through activating CRL5, UBE2F selectively promotes lung cancer cell survival
and could, therefore, serve as a novel cancer target. Clin Cancer Res; 23(4);
1104-16. ©2016 AACR. |
What is break induced replication? | Break-induced replication (BIR) is an important pathway specializing in repair of one-ended double-strand DNA breaks (DSBs). This type of DSB break typically arises at collapsed replication forks or at eroded telomeres. BIR initiates by invasion of a broken DNA end into a homologous template followed by initiation of DNA synthesis that can proceed for hundreds of kilobases. | |
What is a fibrocyte? | Fibrocytes are bone marrow-derived progenitor cells that produce growth factors and contribute to fibrogenesis in the lungs. Fibrocytes are circulating mesenchymal precursors (CD45+, col 1+) recruited to fibrotic areas. | Fibrocytes are circulating mesenchymal precursors (CD45+, col 1+) recruited to
fibrotic areas. Fibrocytes secrete profibrotic mediators including periostin; a
matricellular protein that regulates cellular interactions with extracellular
matrix (ECM) components. In bleomycin-induced fibrosis, periostin deficiency in
structural or hematopoietic cells limits development of pulmonary fibrosis. To
determine if hematopoietic-derived fibrocytes might secrete soluble factors to
activate structural myofibroblast differentiation, wild-type (WT) fibroblasts
were treated with conditioned medium from fibrocytes isolated from
bleomycin-treated WT or periostin-/- mice. After 24 h we saw less α-smooth
muscle actin expression in cells treated with conditioned medium from
periostin-/- fibrocytes. Adoptive transfer of WT fibrocytes augmented lung
fibrosis to a greater extent than transfer of fibrocytes from periostin-/- mice.
In vitro analysis of fibrocytes and fibroblasts isolated from WT and
periostin-/- mice treated with TGFβ1 or periostin demonstrated co-regulation of
mesenchymal activation and beta 1 integrin as a potential receptor for periostin
on fibrocytes. Additionally, connective tissue growth factor (CTGF) mRNA
expression was increased in fibrocytes treated with periostin whereas CTGF and
lysl oxidase (LOX) mRNA expression was low in bleomycin-treated periostin-/-
fibrocytes. These data suggest fibrocytes may augment bleomycin-induced fibrosis
via secretion of periostin and other soluble factors that promote myofibroblast
differentiation. BACKGROUND: The role of fibrocytes in chronic obstructive pulmonary disease
(COPD) is unknown. We sought to enumerate blood and tissue fibrocytes in COPD
and determine the association of blood fibrocytes with clinical features of
disease.
METHODS: Utilizing flow cytometry to identify circulating, collagen type 1+
cells, we found two populations: (i) CD45+ CD34+ (fibrocytes) and (ii) CD45+
CD34- [myeloid-derived suppressor cell (MDSC)-like fibrocytes] cells in stable
COPD (n = 41) and control (n = 29) subjects. Lung resection material from a
separate group of subjects with (n = 11) or without (n = 11) COPD was collected
for tissue fibrocyte detection. We examined circulating fibrocyte populations
for correlations with clinical parameters including quantitative computed
tomography (qCT) and determined pathways of association between correlated
variables using a path analysis model.
RESULTS: Blood and tissue fibrocytes were not increased compared to control
subjects nor were blood fibrocytes associated with lung function or qCT, but
were increased in eosinophilic COPD. Myeloid-derived suppressor cell-like
fibrocytes were increased in COPD compared to controls [2.3 (1.1-4.9), P =
0.038]. Our path analysis model showed that collagen type 1 intensity for
MDSC-like fibrocytes was positively associated with lung function through
associations with air trapping, predominately in the upper lobes.
CONCLUSION: We have demonstrated that two circulating populations of fibrocyte
exist in COPD, with distinct clinical associations, but are not prevalent in
proximal or small airway tissue. Blood MDSC-like fibrocytes, however, are
increased and associated with preserved lung function through a small
airway-dependent mechanism in COPD. Non-healing diabetic wounds are difficult to treat. They also create heavy
ficial burdens for both patients and society. Negative pressure wound therapy
(NPWT) has been adopted to treat intractable wounds and has proved to be
effective. However, the mechanisms that underlie the effects of this treatment
are not entirely understood. Circulating fibrocytes are unique
haematopoietic-derived stem cells that have been reported to play a pivotal role
in wound healing. Here, we have investigated the effect of NPWT on fibrocyte
mobilization and the role of fibrocyte mobilization in the healing of diabetic
wounds during NPWT. We show that the NPWT group exhibited 2.6-fold to 12.1-fold
greater numbers of tail vein-injected PKH-26-labelled fibrocytes in the diabetic
wound sites compared with the control group. We also demonstrate that the
full-thickness skin wounds treated with NPWT exhibit significantly reduced mRNA
and protein expression, blood vessel density and proliferating cells when
exogenous fibrocyte mobilization is inhibited. We speculate that systemic
mobilization of fibrocytes during NPWT may be a mechanism for healing
intractable wounds in a diabetic rat model experiment and that enhancement of
cell mobilization may represent a potential treatment idea for intractable wound
healing across all fields of surgery. Myelofibrosis (MF) may be caused by various pathogenic mechanisms such as
elevation in circulating cytokine levels, cellular interactions and genetic
mutations. However, the underlying mechanism of MF still remains unknown. Recent
studies have revealed that fibrocytes, the spindle-shaped fibroblast-like
hematopoietic cells, and the thrombopoietin (TPO)/myeloproliferative leukemia
protein (MPL; TPO receptor) signaling pathway play a certain role in the
development of MF. In the present study, we aimed to investigate the
relationship between fibrocytes and MPL activation. We showed that TPO or a TPO
receptor agonist directly induces fibrocyte differentiation using murine
fibrocyte cell lines and a murine MF model. Conversely, elimination of
macrophages expressing MPL by clodronate liposomes reversed the MF phenotype of
the murine model, suggesting that fibrocyte differentiation induced by MPL
activation contributes to the progression of MF. Furthermore, we revealed that
SLAMF7high MPLhigh monocytes in human peripheral blood mononuclear cells were
possible fibrocyte precursors and that these cells increased in number in MF
patients not treated with ruxolitinib. Our findings confirmed a link between
fibrocytes and the TPO/MPL signaling pathway, which could result in a greater
understanding of the pathogenesis of MF and lead to the development of novel
therapeutic interventions. Fibrocytes, ahematopoietic stem cell source of fibroblasts/myofibroblasts, were
previously implicated to infiltrate into the intestinal and enhance
inflammation.The aims of the present study were to elucidate the role of
fibrocytes in necrotizing enterocolitis (NEC) pathogenesis and to explore the
mechanisms by which fibrocytes contributed to the inflammatory responses.We
investigated circulating and intestinal local fibrocytes from 32 patients with
NEC, 8 patients with noninflammatory conditions of the gastrointestinal tract
and 12 normal subjects.Significantly higher numbers of circulating fibrocytes
were found in the peripheral blood from NEC patients than the controls
(P < .01). Numerous fibrocytes were found infiltrating the NEC intestinal mucous
membranes. The percentage of fibrocytes to total leukocytes in the NEC
inflammatory lesions was significantly increased compared with the percentage in
the noninflammatory gastrointestinal tract. The fibrocyte attractant chemokine
C-X-C motif chemokine ligand 12 (CXCL12) was significantly increased in the
plasma and was detectable in 80% of the peritoneal lavage fluid from NEC
patients but not the controls. Furthermore, chemokine expression was increased
in fibrocytes infiltrating and trafficking to leukocyte sites. In culture,
lipopolysaccharide (LPS) induced a significant increase in the expression of the
Toll-like receptor (TLR4) signal, with the upregulation of p38 in both the
isolated fibrocytes and macrophages. Similarly, interleukin (IL)-1β induced
increased the upregulation of the IL-6, tumor necrosis factor (TNF)-α, and
intercellular cell adhesion molecule-1 mRNAs but downregulated ColI in
fibrocytes isolated from NEC patients compared with the controls.These findings
indicate that circulating fibrocytes are increased in NEC patients and may be
recruited to the inflammatory intestinal track, most likely through the
CXCR4/CXCL12 axis. These cells may contribute to intestinal inflammation through
TLR4 signaling by producing the TNF-α and IL-6 cytokines. BACKGROUND: Nintedanib, a tyrosine kinase inhibitor that is specific for
platelet-derived growth factor receptors (PDGFR), fibroblast growth factor
receptors (FGFR), and vascular endothelial growth factor receptors (VEGFR), has
recently been approved for idiopathic pulmonary fibrosis. Fibrocytes are bone
marrow-derived progenitor cells that produce growth factors and contribute to
fibrogenesis in the lungs. However, the effects of nintedanib on the functions
of fibrocytes remain unclear.
METHODS: Human monocytes were isolated from the peripheral blood of healthy
volunteers. The expression of growth factors and their receptors in fibrocytes
was analyzed using ELISA and Western blotting. The effects of nintedanib on the
ability of fibrocytes to stimulate lung fibroblasts were examined in terms of
their proliferation. The direct effects of nintedanib on the differentiation and
migration of fibrocytes were also assessed. We investigated whether nintedanib
affected the accumulation of fibrocytes in mouse lungs treated with bleomycin.
RESULTS: Human fibrocytes produced PDGF, FGF2, and VEGF-A. Nintedanib and
specific inhibitors for each growth factor receptor significantly inhibited the
proliferation of lung fibroblasts stimulated by the supernatant of fibrocytes.
Nintedanib inhibited the migration and differentiation of fibrocytes induced by
growth factors in vitro. The number of fibrocytes in the bleomycin-induced lung
fibrosis model was reduced by the administration of nintedanib, and this was
associated with anti-fibrotic effects.
CONCLUSIONS: These results support the role of fibrocytes as producers of and
responders to growth factors, and suggest that the anti-fibrotic effects of
nintedanib are at least partly mediated by suppression of fibrocyte function. |
Which cellular functions are affected by lncRNA H19 in the heart? | H19 could inhibit autophagy in cardiomyocytes by epigenetically silencing of DIRAS3. Elevated H19 promotes apoptosis through PA2G4. Downregulation of H19 promotes proliferation and inhibits apoptosis. H19 induces mineralization of valve interstitial cells. H19 contributes to cardiac fibroblast proliferation and fibrosis, which act in part through repression of DUSP5/ERK1/2. | Down-regulation of DUSP5 has been shown to increase cell proliferation. DUSP5
expression is regulated through epigenetic events involving LncRNA H19 human
choriocarcinoma cell line. However, the molecular mechanisms of H19 modulating
the DUSP5 expression in cardiac fibrosis remain largely unknown. Here, we
identify H19 negatively regulation of DUSP5 gene expression in cardiac
fibroblast and fibrosis tissues. In vivo, the expression levels of H19, DUSP5,
α-SMA, p-ERK1/2, and ERK1/2 in cardiac fibrosis tissue were estimated by Western
blotting, quantitative reverse transcription-polymerase chain reaction and
immunohistochemistry. In vitro stimulation of freshly isolated rat cardiac
fibroblasts with recombit marine TGF-β1 was performed, followed by
quantitative reverse transcription-polymerase chain reaction and Western
blotting to detect changes in H19, DUSP5, p-ERK1/2, and ERK1/2 levels. Cardiac
fibroblasts were transfected with pEX-3-H19 overexpressing, H19-RNAi
down-regulating, or pEGFP-C1-DUSP5 overexpressing. Finally, cell proliferation
was assessed by the MTT assay and cell cycle. H19 endogenous expression is
overexpressed in cardiac fibroblast and fibrosis tissues, and an opposite
pattern is observed for DUSP5. H19 ectopic overexpression reduces DUSP5
abundance and increases the proliferation of cardiac fibroblast, whereas H19
silencing causes the opposite effects. In a broader perspective, these results
demonstrated that LncRNA H19 contributes to cardiac fibroblast proliferation and
fibrosis, which act in part through repression of DUSP5/ERK1/2. BACKGROUND: Calcific aortic valve disease is characterized by an abnormal
mineralization of the aortic valve. Osteogenic activity in the aortic valve is
under the control of NOTCH1, which regulates the expression of key
pro-osteogenic genes such as RUNX2 and BMP2. Long noncoding RNAs (lncRNAs) may
reprogram cells by altering the gene expression pattern.
METHODS: Multidimensional genomic profiling was performed in human aortic valves
to document the expression of lncRNAs and the DNA methylation pattern in
calcific aortic valve disease. In-depth functional assays were carried out to
document the impact of lncRNA on the mineralization of the aortic valve.
RESULTS: We documented that lncRNA H19 (H19) was increased in calcific aortic
valve disease. Hypomethylation of the promoter region was observed in
mineralized aortic valves and was inversely associated with H19 expression.
Knockdown and overexpression experiments showed that H19 induces a strong
osteogenic phenotype by altering the NOTCH1 pathway. Gene promoter analyses
showed that H19 silenced NOTCH1 by preventing the recruitment of p53 to its
promoter. A knockdown of H19 in valve interstitial cells (VICs) increased the
expression of NOTCH1 and decreased the level of RUNX2 and BMP2, 2 downstream
targets repressed by NOTCH1. In rescue experiments, the transfection of a vector
encoding for the active Notch intracellular domain prevented H19-induced
mineralization of valve interstitial cells.
CONCLUSIONS: These findings indicate that a dysregulation of DNA methylation in
the promoter of H19 during calcific aortic valve disease is associated with a
higher expression of this lncRNA, which promotes an osteogenic program by
interfering with the expression of NOTCH1. |
Dinutuximab is used for treatment of which disease? | Dinutuximab, a monoclonal antibody against disialoganglioside, is used for treatment of high-risk neuroblastoma. | PURPOSE: Dinutuximab (Unituxin™; ch14.18), a monoclonal antibody against
disialoganglioside, improved survival as part of post-consolidation therapy for
high-risk neuroblastoma. United Therapeutics Corporation (UTC) assumed ch14.18
production from the National Cancer Institute (NCI); this study evaluates
pharmacokinetic comparability, safety, and tolerability of UTC and NCI products.
METHODS: In this randomized, two-sequence crossover study, 28 patients aged
≤8 years with high-risk neuroblastoma received equivalent ch14.18-UTC or
ch14.18-NCI doses. Despite comparable protein content, nominal doses differed:
17.5 mg/m(2)/day (ch14.18-UTC) and 25 mg/m(2)/day (ch14.18-NCI). Patients
received one product during therapy cycles 1 and 2, the other during cycles 3-5.
Ch14.18 pharmacokinetic profile characterization used population modeling
(NONMEM(®) version 7.2). A two-compartment model with first-order distribution
and elimination processes described pharmacokinetic data. Estimated product
parameters were normalized to UTC nominal dose. For pharmacokinetic
comparability, the final model was used to estimate exposure ratios (UTC/NCI)
and associated 90 % confidence intervals (CIs) for area under the curve from
time zero to infinity (AUCinf) and maximum concentration (C max). All
comparisons were based on a standardized single-dose regimen (17.5 mg/m(2) over
10 h).
RESULTS: Final-model pharmacokinetic parameters were similar to previously
published ch14.18-NCI parameters and comparable for UTC and NCI products.
Products' systemic exposures were comparable, with 90 % CIs around ratios for
AUCinf (0.96; 90 % CI 0.88-1.04) and C max (1.04; 90 % CI 0.98-1.11) within
standard bioequivalence bounds (90 % CI 0.80-1.25). Products' adverse events
were similar and consistent with those previously reported.
CONCLUSIONS: Equivalent actual ch14.18-UTC and ch14.18-NCI doses produced
comparable exposures, with no notable safety or tolerability differences. Dinutuximab (ch14.18; Unituxin™) is a chimeric human-mouse monoclonal antibody
that binds to the glycolipid antigen disialoganglioside, which is highly
expressed on the surface of neuroblastoma cells. This intravenous drug is
approved in the EU and USA as combination therapy with granulocyte-macrophage
colony-stimulating factor (GM-CSF), interleukin (IL)-2 and isotretinoin for the
postconsolidation treatment of patients with high-risk neuroblastoma. In a
multinational, phase III study in this patient population, event-free survival
(EFS) benefits with the dinutuximab-containing regimen versus isotretinoin alone
were observed at the time of the primary (p = 0.0115) and confirmatory
(p = 0.0330) efficacy analyses, although the observed p-value for the
between-group difference in EFS for the primary efficacy analysis did not cross
the prespecified boundary for statistical significance (p < 0.0108). Significant
and sustained (5 years) overall survival benefits were seen with the
dinutuximab-containing regimen versus isotretinoin alone. Despite pretreatment
with analgesics, antihistamines and antipyretics, serious adverse reactions have
been reported with the dinutuximab-containing regimen, with infusion reactions
and neuropathy prompting the US FDA to issue boxed warnings. Dinutuximab
administered in combination with GM-CSF, IL-2 and isotretinoin represents an
important advance in the postconsolidation treatment of patients with high-risk
neuroblastoma, with its benefits outweighing its risks in a patient population
with a poor prognosis and limited therapeutic options. OBJECTIVE: To review the pharmacology, pharmacokinetics, efficacy, safety,
dosage and administration, and formulary considerations for dinutuximab.
DATA SOURCES: MEDLINE was searched (1964 to January 2016) using the terms
ch14.18, dinutuximab, immunotherapy, and neuroblastoma. Other information was
identified from package insert, Biologics License Application, abstracts, news
releases, and ClinicalTrials.gov.
STUDY SELECTION AND DATA EXTRACTION: Identified English-language articles were
reviewed. Selected studies included phase I through III.
DATA SYNTHESIS: High-risk neuroblastoma is primarily a childhood cancer with
5-year survival rates of 40% to 50%. Treatment for high-risk neuroblastoma
includes induction chemotherapy, surgery, myeloablative chemotherapy with
autologous hematopoietic stem cell transplant, and radiation therapy. For
patients achieving clinical remission, limited treatments exist for preventing
relapse. Dinutuximab is a chimeric, human-murine, anti-GD2 monoclonal antibody
approved in combination with granulocyte-macrophage colony-stimulating factor
(GM-CSF), aldesleukin (interleukin-2 [IL-2]), and isotretinoin (13-cis-retinoic
acid [RA]) for maintece treatment of pediatric patients with high-risk
neuroblastoma who achieve at least a partial response to first-line multiagent,
multimodality therapy. In phase III trials, dinutuximab increased 2-year
event-free survival and overall survival when compared to standard treatment.
Severe adverse effects of dinutuximab include pain, hypersensitivity reactions,
capillary leak syndrome, and hypotension.
CONCLUSIONS: Dinutuximab is the first anti-GD2 monoclonal antibody approved in
combination with GM-CSF, IL-2, and RA for maintece treatment of pediatric
patients with high-risk neuroblastoma who achieve at least a partial response to
first-line multiagent, multimodality therapy. Ongoing research will determine if
dinutuximab could be used earlier in treatment, in nonresponders to initial
therapies, in combination with chemotherapy, or in other cancers. Neuroblastoma (NB) is the most common extra cranial solid tumor of childhood,
with 60% of patients presenting with high risk (HR) NB by means of clinical,
pathological and biological features. The 5-year survival rate for HR-NB remains
below 40%, with the majority of patients suffering relapse from chemorefractory
tumor. Immunotherapy is the main strategy against minimal residual disease and
clinical experience has mostly focused on monoclonal antibodies (MoAb) against
the glycolipid disialoganglioside GD2. Three anti-GD2 antibodies have been
tested in the clinic including murine 14G2a, human-mouse chimeric ch14.18 and
3F8. Anti-GD2 MoAb induces cellular cytoxicity against NB and is most effective
when effector cells like natural killer cells, granulocytes and macrophages are
amplified by cytokines. The combination of cytokines IL-2 and GM-CSF with the
anti-GD2 MoAb ch14.18 (Dinutuximab) has shown a significant improvement in
outcome for HR-NB. The FDA and EMA approved dinutuximab (Unituxin(R)) in 2015
for the treatment of patients with HR-NB who achieved at least a partial
response after multimodality therapy. Neuroblastoma, an embryonic cancer of the sympathetic nervous system, is the
most common extracranial solid tumor in childhood. Dinutuximab (formerly called
ch14.18), a monoclonal antibody targeting the disialoganglioside GD2, has been
shown to significantly improve survival rates in patients with high-risk
neuroblastoma. However, the safe and effective use of dinutuximab therapy in
these high-risk patients requires medical expertise in patient selection,
treatment administration, and the monitoring and management of adverse events.
Findings of the randomized phase III study (ANBL0032) led to the approval of
dinutuximab for the treatment of children with high-risk neuroblastoma.
Multi-institutional nursing approaches to implementing standard protocols ensure
the effective management of high-risk neuroblastoma patients receiving
dinutuximab immunotherapy. Understanding and implementing recommendations for
the management of the clinically important and most common adverse events are
essential to ensuring patient continuation of therapy and improving patient
outcomes. PURPOSE: The pharmacology, clinical efficacy, safety, dosage and administration,
and role in therapy of dinutuximab for the treatment of high-risk pediatric
neuroblastoma are reviewed.
SUMMARY: Dinutuximab (Unituxin, United Therapeutics) is a novel monoclonal
antibody recently approved for use in combination with granulocyte- macrophage
colony-stimulating factor, interleukin-2, and isotretinoin for the treatment of
pediatric patients with high-risk neuroblastoma. Its approval has led to the
first major change in standard recommended first-line maintece therapy for
high-risk pediatric neuroblastoma in over a decade. Dinutuximab causes
antibody-dependent cell-mediated cytotoxicity and complement-dependent
cytotoxicity by binding to GD2, a tumor-associated antigen. The recommended
dosage of dinutuximab is 17.5 mg/m2/day for 4 consecutive days of each 24- or
32-day cycle, for a maximum of 5 cycles. In a Phase III trial, patients who
received dinutuximab as part of combination immunotherapy in addition to
standard maintece therapy had significantly improved 2-year event-free
survival relative to those who received standard maintece therapy alone (66%
versus 46%, p < 0.01). Dinutuximab has a unique adverse-effect profile that
includes infusion reactions, neuropathic pain, and electrolyte abnormalities;
the most common adverse effects observed with dinutuximab use in clinical trials
were pain, pyrexia, myelosuppression, infusion reactions, and electrolyte
abnormalities.
CONCLUSION: Dinutuximab is a novel monoclonal antibody that is efficacious as
part of combination immunotherapy in pediatric patients with high-risk
neuroblastoma. Immunotherapy with the anti-GD2 monoclonal antibody ch14.18, or dinutuximab,
represents an important therapeutic advance in the treatment of pediatric
high-risk neuroblastoma and is now considered part of standard of care in this
patient population. To date, transverse myelitis as a result of dinutuximab
therapy has not been reported in clinical trials or in the published literature.
We describe three patients with clinical symptoms of transverse myelitis,
confirmed via magnetic resoce imaging, shortly following initiation of
dinutuximab. All patients were discontinued from dinutuximab treatment and
received urgent treatment, with rapid improvement in symptoms and resultant
functional recovery. |
What is the ChIP-exo method used for? | Precise Identification of DNA-Binding Proteins Genomic Location by Exonuclease Coupled Chromatin Immunoprecipitation (ChIP-exo). | This unit describes the ChIP-exo methodology, which combines chromatin
immunoprecipitation (ChIP) with lambda exonuclease digestion followed by
high-throughput sequencing. ChIP-exo allows identification of a nearly complete
set of the binding locations of DNA-binding proteins at near-single-nucleotide
resolution with almost no background. The process is initiated by cross-linking
DNA and associated proteins. Chromatin is then isolated from nuclei and
subjected to sonication. Subsequently, an antibody against the desired protein
is used to immunoprecipitate specific DNA-protein complexes. ChIP DNA is
purified, sequencing adaptors are ligated, and the adaptor-ligated DNA is then
digested by lambda exonuclease, generating 25- to 50-nucleotide fragments for
high-throughput sequencing. The sequences of the fragments are mapped back to
the reference genome to determine the binding locations. The 5' ends of DNA
fragments on the forward and reverse strands indicate the left and right
boundaries of the DNA-protein binding regions, respectively. DNA-binding proteins play a crucial role in all living organisms by interacting
with various DNA sequences across the genome. While several methods have been
used to study the interaction between DNA and proteins in vitro, chromatin
immunoprecipitation followed by sequencing (ChIP-seq) has become the standard
technique for identifying the genome-wide location of DNA-binding proteins in
vivo. However, the resolution of standard ChIP-seq methodology is limited by the
DNA fragmentation process and presence of contaminating DNA. A significant
improvement of the ChIP-seq technique results from the addition of an
exonuclease treatment during the immunoprecipitation step (ChIP-exo) that lowers
background noise and more importantly increases the identification of binding
sites to a level near to single-base resolution by effectively footprinting
DNA-bound proteins. By doing so, ChIP-exo offers new opportunities for a better
characterization of the complex and fascinating architecture that resides in
DNA-proteins interactions and provides new insights for the comprehension of
important molecular mechanisms. Chromatin immunoprecipitation (ChIP) is an indispensable tool in the fields of
epigenetics and gene regulation that isolates specific protein-DNA interactions.
ChIP coupled to high throughput sequencing (ChIP-seq) is commonly used to
determine the genomic location of proteins that interact with chromatin.
However, ChIP-seq is hampered by relatively low mapping resolution of several
hundred base pairs and high background signal. The ChIP-exo method is a refined
version of ChIP-seq that substantially improves upon both resolution and noise.
The key distinction of the ChIP-exo methodology is the incorporation of lambda
exonuclease digestion in the library preparation workflow to effectively
footprint the left and right 5' DNA borders of the protein-DNA crosslink site.
The ChIP-exo libraries are then subjected to high throughput sequencing. The
resulting data can be leveraged to provide unique and ultra-high resolution
insights into the functional organization of the genome. Here, we describe the
ChIP-exo method that we have optimized and streamlined for mammalian systems and
next-generation sequencing-by-synthesis platform. |
Where do mitochondrial DNA deletion breakpoints tend to occur? | Circular dichroism and UV spectral analysis demonstrated that mitochondrial G-rich sequences near deletion breakpoints prevalent in human disease form G-quadruplex DNA structures. | The large majority of mitochondrial DNA (mtDNA) deletions analyzed from
mitochondrial myopathies and aging humans have been found to be flanked by
direct repeats, a finding which has led to the slip-replication hypothesis of
deletion formation. In this study, we have characterized 13 mtDNA deletion
breakpoints from skeletal muscle harvested from 9- to 27-year-old rhesus
monkeys. Seven of the deletions, five of which were unique to a particular
animal, did not have direct repeats at the deletion breakpoints. In contrast,
two of the three deletions common to several animals had direct repeats flanking
the breakpoints. It appears, therefore, that at least two different mechanisms
exist by which mtDNA deletions are formed during aging, one requiring and one
independent of flanking direct repeats. Furthermore, the species in which mtDNA
deletions are detected may determine which mechanism predominates. We have recently described an autosomal domit hereditary inclusion body
myopathy (h-IBM). Clinically it is is characterized by congenital joint
contractures and slowly progressive, proximal muscle weakness and
ophthalmoplegia. There is deterioration of muscle function between 30 and 50
years of age. While young patients show minor pathological changes in muscle,
the middle-aged and old patients show rimmed vacuoles and inclusions of
filaments measuring 15-18 nm in diameter. Except for the absence of significant
inflammation the histopathology is similar to that found in sporadic inclusion
body myositis (s-IBM). In s-IBM mitochondrial alterations including cytochrome c
oxidase (COX) -deficient muscle fibers are common. These are due to multiple
mitochondrial DNA (mtDNA) deletions. In this study we investigated the
occurrence of mitochondrial alterations in autosomal domit h-IBM. Young
affected individuals showed no mitochondrial changes but three patients aged 38,
51 and 59 years, respectively, showed ragged red fibers and COX-deficient muscle
fibers. Polymerase chain reaction analysis showed multiple mtDNA deletions. By
in situ hybridization clonal expansions of mtDNA with deletions were
demonstrated in COX-deficient muscle fibers. Most of the analyzed deletion
breakpoints showed nucleotide repeats flanking the deletions. The results show
that COX-deficient muscle fibers and somatic mtDNA deletions are present in this
family with h-IBM. The same factors may be involved in the development of mtDNA
deletions in s-IBM and this family with h-IBM. BACKGROUND: Mitochondrial DNA (mtDNA) deletions cause disease and accumulate
during aging, yet our understanding of the molecular mechanisms underlying their
formation remains rudimentary. Guanine-quadruplex (GQ) DNA structures are
associated with nuclear DNA instability in cancer; recent evidence indicates
they can also form in mitochondrial nucleic acids, suggesting that these non-B
DNA structures could be associated with mtDNA deletions. Currently, the multiple
types of GQ sequences and their association with human mtDNA stability are
unknown.
RESULTS: Here, we show an association between human mtDNA deletion breakpoint
locations (sites where DNA ends rejoin after deletion of a section) and
sequences with G-quadruplex forming potential (QFP), and establish the ability
of selected sequences to form GQ in vitro. QFP contain four runs of either two
or three consecutive guanines (2G and 3G, respectively), and we identified four
types of QFP for subsequent analysis: intrastrand 2G, intrastrand 3G, duplex
derived interstrand (ddi) 2G, and ddi 3G QFP sequences. We analyzed the position
of each motif set relative to either 5' or 3' unique mtDNA deletion breakpoints,
and found that intrastrand QFP sequences, but not ddi QFP sequences, showed
significant association with mtDNA deletion breakpoint locations. Moreover, a
large proportion of these QFP sequences occur at smaller distances to
breakpoints relative to distribution-matched controls. The positive association
of 2G QFP sequences persisted when breakpoints were divided into clinical
subgroups. We tested in vitro GQ formation of representative mtDNA sequences
containing these 2G QFP sequences and detected robust GQ structures by UV-VIS
and CD spectroscopy. Notably, the most frequent deletion breakpoints, including
those of the "common deletion", are bounded by 2G QFP sequence motifs.
CONCLUSIONS: The potential for GQ to influence mitochondrial genome stability
supports a high-priority investigation of these structures and their regulation
in normal and pathological mitochondrial biology. These findings emphasize the
potential importance of helicases that subsequently resolve GQ to maintain the
stability of the mitochondrial genome. Mitochondrial DNA deletions are prominent in human genetic disorders, cancer,
and aging. It is thought that stalling of the mitochondrial replication
machinery during DNA synthesis is a prominent source of mitochondrial genome
instability; however, the precise molecular determits of defective
mitochondrial replication are not well understood. In this work, we performed a
computational analysis of the human mitochondrial genome using the "Pattern
Finder" G-quadruplex (G4) predictor algorithm to assess whether G4-forming
sequences reside in close proximity (within 20 base pairs) to known
mitochondrial DNA deletion breakpoints. We then used this information to map G4P
sequences with deletions characteristic of representative mitochondrial genetic
disorders and also those identified in various cancers and aging. Circular
dichroism and UV spectral analysis demonstrated that mitochondrial G-rich
sequences near deletion breakpoints prevalent in human disease form G-quadruplex
DNA structures. A biochemical analysis of purified recombit human Twinkle
protein (gene product of c10orf2) showed that the mitochondrial replicative
helicase inefficiently unwinds well characterized intermolecular and
intramolecular G-quadruplex DNA substrates, as well as a unimolecular G4
substrate derived from a mitochondrial sequence that nests a deletion breakpoint
described in human renal cell carcinoma. Although G4 has been implicated in the
initiation of mitochondrial DNA replication, our current findings suggest that
mitochondrial G-quadruplexes are also likely to be a source of instability for
the mitochondrial genome by perturbing the normal progression of the
mitochondrial replication machinery, including DNA unwinding by Twinkle
helicase. Next-generation sequencing (NGS) based on massively parallel sequencing (MPS) of
the entire 16,569 bp mitochondrial genome generates thousands of reads for each
nucleotide position. The high-throughput sequence data generated allow the
detection of mitochondrial DNA (mtDNA) point mutations and deletions with the
ability to accurately quantify the mtDNA point mutation heteroplasmy and to
determine the deletion breakpoints. In addition, this method is particularly
sensitive for the detection of low-level mtDNA large deletions and multiple
deletions. It is by far the most powerful tool for molecular diagnosis of mtDNA
disorders. |
Name 4 circular RNA molecules associated with carcinogenesis. | circ-ABCB10 knockdown suppressed the proliferation and increased apoptosis of breast cancer cells.
Hsa_circ_0058246 was elevated in tumor specimens of patients with poor clinical outcomes.
Circ-FBXW7 expression positively associated with glioblastoma patient overall survival.
ciRS-7 promotes the development of cancer by acting as sponge of miR-7. | Circular RNAs (circRNAs) are a class of newly-identified non-coding RNA
molecules. CircRNAs are conserved across different species and display specific
organization, sequence, and expression in disease. Moreover, circRNAs' closed
ring structure, insensitivity to RNase, and stability are advantages over linear
RNAs in terms of development and application as a new kind of clinical marker.
In addition, according to recent studies, circular RNA-7 (ciRS-7) acts as a
sponge of miR-7 and thus inhibits its activity. Numerous evidences have
confirmed expression of miR-7 is dysregulated in cancer tissues, however,
whether ciRS-7 invovled in oncogenesis by acting as sponge of miR-7 remains
unclear. Most recently, a study reported ciRS-7 acted as an oncogene in
hepatocellular carcinoma through targeting miR-7 expression. This suggest
ciRS-7/ miR-7 axis affects oncogenesis, and it provides a new perspective on the
mechanisms of decreased miR-7 expression in cancer tissues. Discovery of sponge
role of circRNAs caused researchers to more closely explore the underlying
mechanism of carcinogenesis and has significant clinical implications, and may
open a new chapter in research on the pathology and treatment of cancers. This
review summarizes the structure and function of circRNAs and provides evidence
for the impact of ciRS-7 in promoting the development of cancer by acting as
sponge of miR-7. Gastric cancer is one of the most common tumors of the digestive system. Here,
analysis of the expression profiles of circular RNAs in advanced gastric
adenocarcinoma and adjacent normal mucosa tissues revealed differential
expression of 306 circular RNAs, among which 273 were predicted to exert
regulatory effects on target microRNAs. The downstream pathway networks of
circular RNA-microRNA were mapped and the node genes were identified. In
particular, we found that the expression of hsa_circ_0058246 was elevated in
tumor specimens of patients with poor clinical outcomes. Our collective findings
indicate that circular RNAs play a critical role in gastric cancer
tumorigenesis. Data from this study provide a new perspective on the molecular
pathways underlying metastasis and recurrence of gastric cancer and highlight
potential therapeutic targets that may contribute to more effective diagnosis
and treatment of the disease. Circular RNA (circRNA) is a key regulator in the development and progression of
human cancers, however its role in breast cancer tumorigenesis is not well
understood. The present study aims to investigate the expression profiles and
potential modulation of circRNA on breast cancer carcinogenesis. Human circRNA
microarray was performed to screen for abnormally expressed circRNA in breast
cancer tissue. Results found circ-ABCB10, was significantly up-regulated in
breast cancer tissue. And results were replicated in a larger sample size. In
vitro, loss-of-function experiments showed circ-ABCB10 knockdown suppressed the
proliferation and increased apoptosis of breast cancer cells. Bioinformatics
prediction program predicted the complementary sequence within circ-ABCB10 and
miR-1271, which was validated by luciferase reporter assay. Finally, miR-1271
rescued the function of circ-ABCB10 on breast cancer cells, confirming the
sponge effect of circ-ABCB10 on miR-1271. Overall, results identified a new
functional circ-ABCB10 in breast cancer tumorigenesis, and reveal the important
regulatory role of circ-ABCB10 through sponging miR-1271, providing a novel
insight for breast cancer pathogenesis. BACKGROUND: Circular RNAs (circRNAs) are RNA transcripts that are widespread in
the eukaryotic genome. Recent evidence indicates that circRNAs play important
roles in tissue development, gene regulation, and carcinogenesis. However,
whether circRNAs encode functional proteins remains elusive, although
translation of several circRNAs was recently reported.
METHODS: CircRNA deep sequencing was performed by using 10 pathologically
diagnosed glioblastoma samples and their paired adjacent normal brain tissues.
Northern blotting, Sanger sequencing, antibody, and liquid chromatograph Tandem
Mass Spectrometer were used to confirm the existence of circ-FBXW7 and its
encoded protein in in two cell lines. Lentivirus-transfected stable U251 and
U373 cells were used to assess the biological functions of the novel protein
invitro and invivo (five mice per group). Clinical implications of circ-FBXW7
were assessed in 38 pathologically diagnosed glioblastoma samples and their
paired periphery normal brain tissues by using quantitative polymerase chain
reaction (two-sided log-rank test).
RESULTS: Circ-FBXW7 is abundantly expressed in the normal human brain (reads per
kilobase per million mapped reads [RPKM] = 9.31). The spanning junction open
reading frame in circ-FBXW7 driven by internal ribosome entry site encodes a
novel 21-kDa protein, which we termed FBXW7-185aa. Upregulation of FBXW7-185aa
in cancer cells inhibited proliferation and cell cycle acceleration, while
knockdown of FBXW7-185aa promoted maligt phenotypes invitro and invivo.
FBXW7-185aa reduced the half-life of c-Myc by antagonizing USP28-induced c-Myc
stabilization. Moreover, circ-FBXW7 and FBXW7-185aa levels were reduced in
glioblastoma clinical samples compared with their paired tumor-adjacent tissues
(P < .001). Circ-FBXW7 expression positively associated with glioblastoma
patient overall survival (P = .03).
CONCLUSIONS: Endogenous circRNA encodes a functional protein in human cells, and
circ-FBXW7 and FBXW7-185aa have potential prognostic implications in brain
cancer. |
Which is the enzymatic activity of nardilysin? | Nardilysin (N-arginine dibasic convertase; Nrdc) is a metalloendopeptidase of the M16 family that promotes ectodomain shedding of the precursor forms of various growth factors and cytokines by enhancing the protease activities of a disintegrin and metalloproteinase (ADAM) proteins. | Chronic inflammation contributes to a wide variety of human disorders. In the
stomach, longstanding gastritis often results in structural alterations in the
gastric mucosa, including metaplastic changes and gastric cancers. Therefore, it
is important to elucidate factors that are involved in gastric inflammation.
Nardilysin (N-arginine dibasic convertase; Nrdc) is a metalloendopeptidase of
the M16 family that promotes ectodomain shedding of the precursor forms of
various growth factors and cytokines by enhancing the protease activities of a
disintegrin and metalloproteinase (ADAM) proteins. Here, we have demonstrated
that Nrdc crucially regulates gastric inflammation caused by Helicobacter felis
infection or forced expression of prostaglandin E2 in K19-C2mE mice. Metaplastic
changes following gastric inflammation were suppressed by the deletion of Nrdc.
Furthremore, the deletion of Nrdc significantly suppressed
N-methyl-N-nitrosourea (MNU)-induced gastric tumorigenesis in the murine
stomach. These data may lead to a global therapeutic approach against various
gastric disorders by targeting Nrdc. |
The Mantoux test detects what latent infection/disease? | screened for TB infection with a Mantoux tuberculin skin testtuberculin skin test (TST) performed according to the Mantoux method. | Detection of latent tuberculosis infection is an important step in the control
of tuberculosis. The tuberculin skin test is the only proven method for
identifying tuberculosis infection in patients who do not have tuberculosis
disease. The prevalence of tuberculosis infection among hospitalized patients in
a pneumological department of an inner-city hospital was evaluated, using the
intradermal tuberculin skin test (Mantoux technique). Interpretation of the
Mantoux test was based on the size of induration in millimeters and the
individual risk profile of the patients, according to the guidelines of the
American Thoracic Society and the Centers for Disease Control, revised in 1989.
Of 697 tested patients, 252 showed test results consistent with tuberculosis
infection (36.2%). 55 of these 697 patients had active tuberculosis disease or a
prior history of tuberculosis (7.9%). A positive tuberculin skin test was found
in 197 of 642 patients (30.7%) with a diagnosis different from tuberculosis
(COPD, pneumonia, cancer and others). In our study, the sensitivity of the
tuberculin skin test for active tuberculosis infection was 95%. The present
study revealed a high prevalence of tuberculosis infection among hospitalized
patients in a pneumological department. Further studies are needed to assess the
usefulness of routine tuberculin skin testing in hospitalized populations. In order to determine the prevalence of latent infection due to Mycobacterium
tuberculosis in drug users and to provide centres for drug users with a
practical tool for tuberculosis screening, 237 drug users were subjected to the
Monotest and, for reference purposes, to the Mantoux test. The overall
prevalence of subjects with a tuberculin skin reaction size > or = 5 mm in the
Mantoux test was 25.7%; utilizing a cut-off of > or = 10 mm, the prevalence was
11.4%. Irrespective of cut-off, the Monotest showed a sensitivity of > 90% and a
specificity of > 80%. At a prevalence of 25.7%, and with cut-offs of > or = 5 or
> or = 10 mm, the positive predictive value was 83% or 62.2%, respectively.
Irrespective of cut-off, the negative predictive value was > 97%. In conclusion,
the Monotest proved satisfactory as a tool for epidemiological screening in a
population with a high prevalence for latent tuberculosis, namely drug users. Tuberculosis is responsible for more then 2 million deaths worldwide each year
and vies with HIV as the world's most fatal infectious disease. In many
developing countries, attempts to control the spread of infection rely solely on
identification and treatment of those with active disease, ignoring subclinical
infection. However, in developed countries, large efforts are also expended to
identify and give prophylactic drugs to people with latent tuberculosis
infection. Until recently, the 100-year-old tuberculin skin test (Mantoux) has
been the only available diagnostic test for latent tuberculosis infection,
despite its many well-known limitations. Advances in scientific knowledge have
led to the development of tests for tuberculosis that measure the production of
interferon-gamma by T-cells stimulated in vitro with Mycobacterium
tuberculosis-specific antigens. These interferon-gamma tests are highly specific
and unaffected by prior Bacille Calmette-Guérin vaccination or immune reactivity
to most atypical mycobacteria. They are more sensitive than the tuberculin skin
test in detecting people with active tuberculosis, and their results correlate
more closely with M. tuberculosis exposure risk factors than the tuberculin skin
test in people likely to have latent tuberculosis infection. Science has caught
up with one of the oldest diagnostic tests still in use worldwide, and the
adoption of new, tuberculosis-specific interferon-gamma-based tests should move
us one step closer to better control of this insidious pathogen. Patients receiving tumor necrosis factor alpha inhibitors for the treatment of
rheumatic diseases (rheumatoid arthritis, psoriatic arthritis, ankylosing
spondylitis) are at high risk of developing tuberculosis during treatment. This
article gives the recommendations for the prevention and management of
tuberculosis in patients with rheumatic diseases before initiating therapy with
tumor necrosis factor alpha inhibitors. They are adapted considering the high
prevalence of tuberculosis, high drug resistance of Mycobacterium tuberculosis,
and extensive bacille Calmette-Guérin vaccination against tuberculosis in
Lithuania. In order to reduce the risk of tuberculosis, the screening should be
done before starting antitumor necrosis factor alpha therapy. This includes
complete medical history and posterior-anterior, lateral chest radiography.
Tuberculin skin test using the Mantoux method with 5 tuberculin units and
interferon-gamma release assay should be performed in patients without
posttuberculous radiological lesions. If Ghon's complex or untreated
posttuberculous lesions are present, or if the results the Mantoux test or
interferon-gamma release assay are positive, the patient should be treated for
latent tuberculosis. For the treatment of latent tuberculosis, isoniazid and
rifampicin are given for 3 months, and the introduction of antitumor necrosis
factor alpha therapy is delayed at least for one month. In cases of suspected
active Mycobacterium tuberculosis infection, tuberculosis should be confirmed
microbiologically or morphologically, and adequate antituberculosis treatment
should be initiated. Diagnosis of tuberculosis (TB) is difficult, since symptoms are often very
unspecific or lacking. However active, prompt and accurate diagnosis is the key
element in the public health response to tuberculosis and the cornerstone of
tuberculosis control. Different diagnostic methods for an assured diagnosis of
TB are necessary. Chest radiography is a useful keystone to identify
tuberculosis, but diagnosis of tuberculosis cannot be established by radiography
alone. CT scanning is used in patients without pathological chest radiography
but clinically suspected active TB and to differentiate TB from other diseases.
Radiological appearance is primarily determined by the immune status of patients
and caverns and disseminated disease foci are often observed. Laboratory
diagnostic methods include microscopic identification of acid-fast mycobacteria
from any body fluid (especially sputum), as well as isolation and
characterisation of mycobacteria in culture. It is then possible to type the
pathogens by the shape of their colony, their growth behavior and their
biochemical characteristics. These methods are regarded as the gold standard in
diagnosis of active TB. In patients who are highly suspected of having TB, but
whose sputum specimens tested negative for mycobacteria, a nucleic acid
amplification test is additionally performed. Moreover, sensitivity testing with
first and second line antitubercular drugs is applied as standard. Laboratory
diagnostic testing of cellular immunity against pathogenic mycobacteria employs
the tuberculin skin test (TST, Mantoux tuberculin test) or the more specific
interferon γ test to determine γ interferon released by T lymphocytes stimulated
in vitro. The new ELISA and ELISPOT procedures exhibit higher test specificity
and less cross reactivity to NTM (non-tuberculosis mycobacteria), are
independent of BCG-vaccination status and correlate better with the degree of
exposure than does the TST. In Russia, an intradermal Diaskintest® drug has been designed, which is a
recombit tuberculosis allergen based on M. tuberculosis-- specific proteins:
ESAT-6 and CFP-10 produced by a genetically modified Escherichia coli culture.
Diaskintest® test and Mantoux test with 2TE PPD-L were concurrently carried out
in 300 children and adolescents with tuberculosis and followed up in risk groups
at a tuberculosis dispensary to determine the sensitivity of the new skin test
in active tuberculosis infection. Diaskintest® showed a high sensitivity not
only in active tuberculosis, but also in occult, the so-called latent,
tuberculosis infection. This is suggested by the following evidence. The high
percentage (83.8%) of positive responses to Diaskintest® is noted in children
and adolescents with tuberculosis, receiving an intensive course of
chemotherapy. Negative tests were observed only in minor forms at the resolution
stage. In the children who had completed treatment, positive tests were seen in
78.3%, moreover in those with prior tuberculosis of intrathoracic lymph nodes;
negative tests were observed not earlier than 18 months after start of
treatment. The highest sensitivity of Diaskintest® was shown in children with
early primary tuberculosis infection and through family contact with
bacteria-excreting subjects (91.7%). These children may be judged with the
highest assurance to have latent tuberculosis infection, the population of which
is in an active state at the moment of the study. The children with early
primary tuberculosis infection, but in no family contact with bacteria-excreting
individuals, showed a lower percentage of positive responses to Diaskintest®
both before (37.5%) and after (10%) treatment, which suggests that there must be
a lower bacterial burden in the child. A high percentage of positive responses
to Diaskintest® (76.2%) were found in subjects with hyperergic reactions to
tuberculin. These were in only 16.7% in the group of patients receiving
preventive therapy. In children and adolescents with a persistent positive
Mantoux test (for more than 3 years), the response to Diaskintest® was negative
in most cases since in early infection when mycobacteria propagated, the
reaction to the drug was positive, but as 3 years pass the probability of the
infection transition to the persistence stage is high--at that time the response
to Diaskintest® becomes negative. Diaskintest® induces no delayed
hypersensitivity associated with BCG vaccination, suggesting its high
specificity. There were no positive reactions in patients with nonspecific lung
diseases. Health care workers (HCW) are particularly at risk of acquiring tuberculosis
(TB), even in countries with low TB incidence. Therefore, TB screening in HCW is
a useful prevention strategy in countries with both low and high TB incidence.
Tuberculin skin test (TST) is widely used although it suffers of low
specificity; on the contrary, the in vitro enzyme immunoassay tests (IGRA) show
superior specificity and sensitivity but are more expensive. The present study
reports the results of a three-year TB surveillance among HCW in a large
teaching hospital in Rome, using TST (by standard Mantoux technique) and IGRA
(by QuantiFERON-TB) as first- and second-level screening tests, respectively.
Out of 2290 HCW enrolled, 141 (6.1%) had a positive TST; among them, 99 (70.2%)
underwent the IGRA and 16 tested positive (16.1%). The frequency of HCW tested
positive for TB seems not far from other experiences in low incidence countries.
Our results confirm the higher specificity of IGRA, but, due to its higher cost,
TST can be considered a good first level screening test, whose positive results
should be further confirmed by IGRA before the patients undergo X-ray diagnosis
and/or chemotherapy. |
What is measured with the Proseek panels? | Differnet Proseek multiplex protein biomarker panels exists: CVD, inflammatory, neurology and oncology biomarker. | Allogeneic hematopoietic stem cell transplantation (aHSCT) is used as a curative
treatment in severe hematological and immunological disorders. Despite clear
improvement of the aHSCT outcome, substantial proportion of patients still
suffers from severe complications, including graft-versus-host disease (GvHD).
The aim of this study was, therefore, to identify inflammation-associated
molecules deregulated in the early serum samples of the patients after aHSCT and
nominate markers associated with particular aHSCT parameters/complications.
Serum concentrations of 92 inflammation-associated proteins were measured in
samples obtained from 80 aHSCT patients 14 days after transplantation and from
23 healthy control subjects by a novel sensitive proximity extension assay
technology using Proseek Multiplex Inflammation I kit. Serum profiles of
inflammatory proteins in patients after aHSCT were substantially different from
those observed in control subjects and related to underlying disease status
before transplantation. Particularly, the difference between aHSCT patients and
controls reached significance level for 57 analytes (40 upregulated, 17
downregulated in aHSCT patients). The concentration of several markers was
associated with the level of donor/recipient HLA match (TGF-α: p corr = 0.025,
HGF: p corr = 0.036) and with complete donor chimerism at day +30 after
allografting (DNER: p corr = 0.042). None of the markers was significantly
associated with acute and chronic GvHD after correction. More than half of
investigated proteins significantly differed between the samples from aHSCT
patients and healthy control subjects as a consequence of the "cytokine storm"
after aHSCT. Comparisons of patient's subgroups based on specific
biological/clinical parameters revealed much less evident differences;
nevertheless, we nominated several markers associated with the level of
donor/recipient HLA match and post-transplant chimerism. OBJECTIVE: The present study evaluates the effect of food intake on 92
biomarkers for cardiovascular disease (CVD).
METHODS: Twenty two healthy subjects (11 male and 11 female aged 25.9±4.2 years)
were investigated. A total of 92 biomarkers were measured before a standardized
meal as well as 30 and 120 minutes afterwards with the Proseek Multiplex CVD III
kit.
RESULTS: The levels for eight biomarkers decreased significantly (P<0.05) 30
minutes after food intake. The levels for seven biomarkers remained
significantly decreased 120 minutes after food intake. Nine biomarker decreased
significantly at 120 minutes after food intake. The changes were between 4-30%,
most commonly around 5%. Only six biomarkers showed a difference of 10% or more
due to food intake. The biggest differences were observed for Insulin-like
growth factor-binding protein 1 (30%); Azurocidin, Cystatin-B, and
Myeloperoxidase (13%); Monocyte chemotactic protein 1 (11%); and Myeloblastin
(10%), all 120 minutes after food intake.
CONCLUSIONS: This study shows that food intake affects several different CVD
biomarkers, but the effect is predomitly modest. Timing of blood sampling in
relation to food intake, therefore, appears not to be a major concern. Further
studies are warranted in older healthy subjects and in patients with various
cardiac diseases to determine whether the findings are reproducible. BACKGROUND: Ischaemic stroke and coronary heart disease are important
contributors to the global disease burden and share atherosclerosis as the main
underlying cause. Recent evidence from a genome-wide association study (GWAS)
suggested that single nucleotide polymorphisms (SNP) near the MMP12 gene at
chromosome 11q22.3 were associated with large-vessel ischaemic stroke. Here, we
evaluated and extended these results by examining the relationship between MMP12
and atherosclerosis in clinical and experimental studies.
METHODS AND RESULTS: Plasma concentrations of MMP12 were measured at baseline in
3394 subjects with high-risk for cardiovascular disease (CVD) using the Olink
ProSeek CVD I array. The plasma MMP12 concentration showed association with
incident cardiovascular and cerebrovascular events (130 and 67 events,
respectively, over 36 months) and carotid intima-media thickness progression (P
= 3.6 × 10-5 ). A GWAS of plasma MMP12 concentrations revealed that SNPs
rs499459, rs613084 and rs1892971 at chr11q22.3 were independently associated
with plasma MMP12 (P < 5 × 10-8 ). The lead SNPs showed associations with mRNA
levels of MMP12 and adjacent MMPs in atherosclerotic plaques. MMP12
transcriptomic and proteomic levels were strongly significantly increased in
carotid plaques compared with control arterial tissue and in plaques from
symptomatic versus asymptomatic patients. By combining immunohistochemistry and
proximity ligation assay, we demonstrated that MMP12 localizes to CD68 +
macrophages and interacts with elastin in plaques. MMP12 silencing in human
THP-1-derived macrophages resulted in reduced macrophage migration.
CONCLUSIONS: Our study supports the notion that MMP12 is implicated in
large-artery atherosclerotic stroke, functionally by enhancing elastin
degradation and macrophage invasion in plaques. BACKGROUND: Systemic lupus erythematosus (SLE) is a remarkably heterogeneous
autoimmune disease. Despite tremendous efforts, our knowledge of serum protein
patterns in severe SLE phenotypes is still limited. We investigated the serum
protein pattern of SLE, with special emphasis on irreversible organ damage and
active lupus nephritis (LN) as assessed by renal Systemic Lupus Erythematosus
Disease Activity Index.
METHODS: We used proximity extension immunoassay (PEA, Proseek Multiplex, Olink)
to assess the serum levels of ninety-two inflammation-related proteins in Czech
patients with SLE (n = 75) and age-matched healthy control subjects (n = 23).
Subgroup analysis was carried out on the basis of organ damage (with/without,
42/33) and biopsy-proven LN (with/without, 27/48; active LN, n = 13; inactive
LN, n = 14).
RESULTS: Of thirty deregulated proteins between SLE and the healthy controls
(Pcorr < 0.05), the top upregulated proteins in SLE were sirtuin 2, interleukin
18 (IL18), and caspase 8 (Pcorr < 0.0006). Of these, sirtuin 2 and caspase 8
had not yet been reported with SLE. Elevated levels of IL8, CCL2/MCP1, CCL11,
and MMP10 (Pcorr < 0.05) were detected in patients with organ damage for which
the serum levels of CCL11 and MMP10 were particularly informative in organ
damage prediction. Comparing patients based on LN, elevated levels of CSF1,
sIL15RA, sCD40, sCX3CL1, caspase 8, sIL18R1, bNGF, and GDNF (Pcorr < 0.05) were
detected in active LN. Except GDNF, all LN-associated markers showed usefulness
in prediction of active renal disease.
CONCLUSIONS: This highly sensitive PEA analysis identified the serum pattern of
SLE, organ damage, and active LN, with many novel candidate proteins detected.
Their exact role and suitability as biomarkers in SLE deserve further
investigation. Serum protein fingerprints associated with MGUS and MM and their changes in MM
after autologous stem cell transplantation (MM-ASCT, day 100) remain unexplored.
Using highly-sensitive Proximity Extension ImmunoAssay on 92 cancer biomarkers
(Proseek Multiplex, Olink), enhanced serum levels of Adrenomedullin (ADM, Pcorr=
.0004), Growth differentiation factor 15 (GDF15, Pcorr= .003), and soluble Major
histocompatibility complex class I-related chain A (sMICA, Pcorr= .023), all
prosurvival and chemoprotective factors for myeloma cells, were detected in MM
comparing to MGUS. Comparison of MGUS and healthy subjects revealed elevation of
angiogenic and antia-poptotic midkine (Pcorr= .0007) and downregulation of
Transforming growth factor beta 1 (TGFB1, Pcorr= .005) in MGUS. Importantly,
altered serum pattern was associated with MM-ASCT compared to paired MM at the
diagnosis as well as to healthy controls, namely by upregulated B-Cell
Activating Factor (sBAFF) (Pcorr< .006) and sustained elevation of other
pro-tumorigenic factors. In conclusion, the serum fingerprints of MM and MM-ASCT
were characteristic by elevated levels of prosurvival and chemoprotective
factors for myeloma cells. BACKGROUND: Currently, there are no FDA approved screening tools for detecting
early stage ovarian cancer in the general population. Development of a
biomarker-based assay for early detection would significantly improve the
survival of ovarian cancer patients.
METHODS: We used a multiplex approach to identify protein biomarkers for
detecting early stage ovarian cancer. This new technology (Proseek® Multiplex
Oncology Plates) can simultaneously measure the expression of 92 proteins in
serum based on a proximity extension assay. We analyzed serum samples from 81
women representing healthy, benign pathology, early, and advanced stage serous
ovarian cancer patients.
RESULTS: Principle component analysis and unsupervised hierarchical clustering
separated patients into cancer versus non-cancer subgroups. Data from the
Proseek® plate for CA125 levels exhibited a strong correlation with current
clinical assays for CA125 (correlation coefficient of 0.89, 95% CI 0.83, 0.93).
CA125 and HE4 were present at very low levels in healthy controls and benign
cases, while higher levels were found in early stage cases, with highest levels
found in the advanced stage cases. Overall, significant trends were observed for
38 of the 92 proteins (p < 0.001), many of which are novel candidate serum
biomarkers for ovarian cancer. The area under the ROC curve (AUC) for CA125 was
0.98 and the AUC for HE4 was 0.85 when comparing early stage ovarian cancer
versus healthy controls. In total, 23 proteins had an estimated AUC of 0.7 or
greater. Using a naïve Bayes classifier that combined 12 proteins, we improved
the sensitivity corresponding to 95% specificity from 93 to 95% when compared to
CA125 alone. Although small, a 2% increase would have a significant effect on
the number of women correctly identified when screening a large population.
CONCLUSIONS: These data demonstrate that the Proseek® technology can replicate
the results established by conventional clinical assays for known biomarkers,
identify new candidate biomarkers, and improve the sensitivity and specificity
of CA125 alone. Additional studies using a larger cohort of patients will allow
for validation of these biomarkers and lead to the development of a screening
tool for detecting early stage ovarian cancer in the general population. |
Is Enlimomab effective for stroke treatment? | No. Anti-ICAM therapy with enlimomab is not an effective treatment for ischemic stroke in and may significantly worsen stroke outcome. | A growing body of evidence, primarily from animal models of cerebral ischemia
and preliminary human studies, indicates that inflammatory mechanisms contribute
to secondary neuronal injury after acute cerebral ischemia. Ischemia followed by
reperfusion rapidly leads to the expression of inflammatory cytokines,
particularly tumor necrosis factor-alpha and interleukin-1beta, which stimulate
a complex cascade of events involving local endothelial cells, neurons,
astrocytes, and perivascular cells. A secondary response includes the release of
other cytokines, an increase in components of the coagulation system, an
upregulation of cell adhesion molecule expression, and changes in the expression
of components of the immune response. The net effect of these events is
transformation of the local endothelium to a prothrombotic/proinflammatory state
and induction of leukocyte migration to the site of injury. A number of studies
have shown that leukocyte migration occurs within hours of reperfusion.
Leukocytes accumulate in the injured region, where they cause tissue injury by
several mechanisms, including occlusion of microvasculature, generation of
oxygen free radicals, release of cytotoxic enzymes, alteration of vasomotor
reactivity, and increase in cytokine and chemoattractant release. Monoclonal
antibodies against leukocyte adhesion molecules have been shown to reduce
infarct volume in animal models of ischemia-reperfusion. However, this treatment
failed to show benefit in the Enlimomab Acute Stroke Trial. A number of factors
may complicate the use of antibody directed adhesion molecule blockade in acute
stroke and will be discussed in this article. Overall, an increased
understanding of inflammatory and immunologic mechanisms still offers great
potential for reducing acute stroke injury. BACKGROUND: There has been recent interest in the possible role of
reperfusion-induced inflammation with neuronal injury after stroke. Enlimomab, a
murine intercellular adhesion molecule-1 (ICAM-1) antibody, reduces leukocyte
adhesion and infarct size in experimental stroke studies. The purpose of the
current clinical trial was to evaluate the use of enlimomab after ischemic
stroke.
METHODS: A total of 625 patients with ischemic stroke were randomized to receive
either enlimomab (n = 317) or placebo (n = 308) within 6 hours of stroke onset.
Treatment was given over 5 days. Patients were evaluated at baseline and on days
5 and 90 after initiation of treatment; long-term assessments were carried out
after 6 and 12 months. The primary efficacy endpoint was the response to therapy
at 90 days on the Modified Rankin Scale; other endpoints included Barthel Index
(BI) and NIH Stroke Scale and survival.
RESULTS: At day 90, the Modified Rankin Scale score was worse in patients
treated with enlimomab than with placebo (p = 0.004). Fewer patients had
symptom-free recovery on enlimomab than placebo (p = 0.004), and more died (22.2
versus 16.2%). The negative effect of enlimomab was apparent on days 5, 30, and
90 of treatment (p = 0.005). There were significantly more adverse events with
enlimomab treatment than placebo, primarily infections and fever. Patients
experiencing fever were more likely to have a poor outcome or die.
CONCLUSIONS: The authors conclude that anti-ICAM therapy with enlimomab is not
an effective treatment for ischemic stroke in the model studied and, indeed, may
significantly worsen stroke outcome. BACKGROUND AND PURPOSE: Enlimomab, a murine monoclonal anti-human intercellular
adhesion molecule (ICAM)-1 antibody, had a negative outcome in a multicenter
acute-stroke trial. We did a bedside-to-bench study in standardized rat stroke
models to explore mechanisms for these untoward results.
METHODS: After focal brain ischemia in Wistar rats and spontaneously
hypertensive rats (SHR), we administered murine anti-rat ICAM-1 antibody (1A29),
subclass-matched murine immunoglobulin (IgG1), or vehicle intravenously. To
examine whether rat anti-mouse antibodies were generated against the mouse
protein and whether these were deleterious, we sensitized Wistar rats with 1A29
or vehicle 7 days before surgery. Infarct volume, tissue myeloperoxidase
activity, neutrophil CD11b expression, and microvascular E-selectin, P-selectin,
and ICAM-1 expression were examined 48 hours after surgery. Complement
activation was serially assessed for 2 hours after a single injection of either
1A29 or vehicle.
RESULTS: 1A29 treatment did not significantly reduce infarct size in either
strain. 1A29 sensitization augmented infarct size and generated rat anti-mouse
antibodies. Although 1A29 inhibited neutrophil trafficking shown by reduction in
brain myeloperoxidase activity, circulating neutrophils were activated and
displayed CD11b upregulation. Complement was activated in 1A29-sensitized Wistar
rats and 1A29-treated SHR. E-selectin (SHR), endothelial P-selectin (Wistar and
SHR), and ICAM-1 (SHR) were upregulated in animals treated with 1A29.
CONCLUSIONS: Administration to rats of a murine antibody preparation against
ICAM-1, 1A29, elicits the production of host antibodies against the protein,
activation of circulating neutrophils, complement activation, and sustained
microvascular activation. These observations provide several possible mechanisms
for central nervous system-related clinical deterioration that occurred when
Enlimomab was given in acute ischemic stroke. Animal models of focal ischaemia induced by middle cerebral artery occlusion
(MCAO) provide most evidence for cellular inflammatory responses in stroke.
Permanent MCAO results in a modest neutrophil infiltration at 24 h after
ischaemia, predomitly around arterial vessels at the margins of infarction,
whereas MCAO with subsequent reperfusion is associated with substantial
infiltration by neutrophils throughout the entire infarct. Several studies show
that C-reactive protein (CRP), an inflammatory marker, is associated with stroke
outcomes and future vascular events. Several drugs, especially
hydroxymethylglutaryl coenzyme A reductase inhibitors (statins), have been
demonstrated to reduce hsCRP levels independently of their effects on plasma
cholesterol. Various cytokines were shown to be expressed in the injured brain.
Recent investigations demonstrated that mRNAs of above cytokines were induced in
the ischemic rat brain. TNF-alpha is a pleiotropic cytokine that mediates key
roles in many physiological and pathological cellular processes including acute
and chronic inflammation, programmed cell death or apoptosis, anti-tumor
responses, and infection. Pharmaceutical industry to search a small molecule TNF
inhibitor have taken multiple strategies. Significant protection after in vivo
oral use of SB-239063 from brain injury and neurological deficits was observed
in one study. In the same study significant protection from brain injury and
neurological deficits was also demonstrated due to i.v post-stroke treatment
with the same compound. Leukocyte-endothelial adhesion process consists of
several steps, beginning with rolling of the leukocyte on the endothelial
surface until it has slowed down to such a degree that it sticks to the
endothelium. Treatment with a murine anti-ICAM-1 antibody (enlimomab) has been
investigated in patients with acute ischemic stroke in the Enlimomab Acute
Stroke Trial (EAST). Unfortunately, the case fatality rate in this trial was
significantly higher in the enlimomab patient group than in the placebo group.
Furthermore, experimental data have shown that focal cerebral ischemia induces a
time-dependent activation of granulocytes, lymphocytes, and macrophages.
Dissipation of ATP by CD39 reduced P2X7 receptor stimulation and thereby
suppressed baseline leukocyte alphaMbeta2-integrin expression. As
alphaMbeta2-integrin blockade reversed the postischemic, inflammatory phenotype
of Cd39-/- mice, these data suggest that phosphohydrolytic activity on the
leukocyte surface suppresses cell-cell interactions that would otherwise promote
thrombosis or inflammation. |
Are AAV vectors considered for the treatment of retinal dystrophies? | Yes, AAV vectors are considered for the treatment of retinal dystrophies. | Clinical trials treating inherited retinal dystrophy caused by RPE65 mutations
had put retinal gene therapy at the forefront of gene therapy. Both successes
and limitations in these clinical trials have fueled developments in gene
vectors, which continue to further advance the field. These novel gene vectors
aim to more safely and efficiently transduce retinal cells, expand the gene
packaging capacity of AAV, and utilize new strategies to correct the varying
mechanisms of dysfunction found with inherited retinal dystrophies. With recent
clinical trials and numerous pre-clinical studies utilizing these novel vectors,
the future of ocular gene therapy continues to hold vast potential. |
Does International Citicoline Trial on acUte Stroke trial supports efficacy of citicoline for stroke treatment? | No. The International Citicoline Trial on acUte Stroke (ICTUS) found that citocoline is not efficacious in the treatment of moderate-to-severe acute ischaemic stroke. | BACKGROUND: Citicoline is approved in some countries for the treatment of acute
ischaemic stroke. The drug has shown some evidence of efficacy in a pooled
analysis. We sought to confirm the efficacy of citicoline in a larger trial.
METHODS: We undertook a randomised, placebo-controlled, sequential trial in
patients with moderate-to-severe acute ischaemic stroke admitted at university
hospitals in Germany, Portugal, and Spain. Using a centralised minimisation
process, patients were randomly assigned in a 1:1 ratio to receive citicoline or
placebo within 24 h after the onset of symptoms (1000 mg every 12 h
intravenously during the first 3 days and orally thereafter for a total of 6
weeks [2×500 mg oral tablets given every 12 h]). All study participants were
masked. The primary outcome was recovery at 90 days measured by a global test
combining three measures of success: National Institutes of Health Stroke Scale
≤1, modified Rankin score ≤1, and Barthel Index ≥95. Safety endpoints included
symptomatic intracranial haemorrhage in patients treated with recombit tissue
plasminogen activator, neurological deterioration, and mortality. This trial is
registered, NCT00331890.
RESULTS: 2298 patients were enrolled into the study from Nov 26, 2006, to Oct
27, 2011. 37 centres in Spain, 11 in Portugal, and 11 in Germany recruited
patients. Of the 2298 patients who gave informed consent and underwent
randomisation, 1148 were assigned to citicoline and 1150 to placebo. The trial
was stopped for futility at the third interim analysis on the basis of complete
data from 2078 patients. The final randomised analysis was based on data for
2298 patients: 1148 in citicoline group and 1150 in placebo group. Global
recovery was similar in both groups (odds ratio 1·03, 95% CI 0·86-1·25;
p=0·364). No significant differences were reported in the safety variables nor
in the rate of adverse events.
INTERPRETATION: Under the circumstances of the ICTUS trial, citicoline is not
efficacious in the treatment of moderate-to-severe acute ischaemic stroke.
FUNDING: Ferrer Grupo. CDP-choline has shown neuroprotective effects in cerebral ischemia. In humans,
although a recent trial International Citicoline Trial on Acute Stroke (ICTUS)
has shown that global recovery is similar in CDP-choline and placebo groups,
CDP-choline was shown to be more beneficial in some patients, such as those with
moderate stroke severity and not treated with t-PA. Several mechanisms have been
proposed to explain the beneficial actions of CDP-choline. We have now studied
the participation of Sirtuin1 (SIRT1) in the neuroprotective actions of
CDP-choline. Fischer rats and Sirt1⁻/⁻ mice were subjected to permanent focal
ischemia. CDP-choline (0.2 or 2 g/kg), sirtinol (a SIRT1 inhibitor; 10 mg/kg),
and resveratrol (a SIRT1 activator; 2.5 mg/kg) were administered
intraperitoneally. Brains were removed 24 and 48 h after ischemia for western
blot analysis and infarct volume determination. Treatment with CDP-choline
increased SIRT1 protein levels in brain concomitantly to neuroprotection.
Treatment with sirtinol blocked the reduction in infarct volume caused by
CDP-choline, whereas resveratrol elicited a strong synergistic neuroprotective
effect with CDP-choline. CDP-choline failed to reduce infarct volume in Sirt1⁻/⁻
mice. Our present results demonstrate a robust effect of CDP-choline like SIRT1
activator by up-regulating its expression. Our findings suggest that therapeutic
strategies to activate SIRT1 may be useful in the treatment of stroke. Sirtuin 1
(SIRT1) is implicated in a wide range of cellular functions. Regarding stroke,
there is no direct evidence. We have demonstrated that citicoline increases
SIRT1 protein levels in brain concomitantly to neuroprotection. Citicoline fails
to reduce infarct volume in Sirt1⁻/⁻ mice. Our findings suggest that therapeutic
strategies acting on SIRT1 may be useful in the treatment of stroke. This study was to evaluate the efficacy and safety of early application of
citicoline in the treatment of patients with acute stroke by meta-analysis.
Randomized controlled trials published until May 2015 were electronically
searched in MEDLINE, Embase, the Cochrane Central Register of Controlled Trials,
WHO International Clinical Trial Registration Platform, Clinical Trial.gov, and
China Biology Medicine disc. Two reviewers independently screened the articles
and extracted the data based on the inclusion and exclusion criteria. The
quality of included articles was evaluated by using Revman5.0, and meta-analysis
was performed. The results showed that 1027 articles were obtained in initial
retrieval, and finally 7 articles, involving a total of 4039 cases, were
included for analysis. The meta-analysis showed that no significant differences
were found in the long-term mortality (OR=0.91, 95% CI 0.07 to 1.09, P=0.30),
the rate of dependency (OR=1.02, 95% CI 0.87 to 1.24, P=0.85), and the effective
rate (OR=0.98, 95% CI 0.84 to 1.14, P=0.82) between citicoline group and control
group. The overall rate of adverse events in citicoline group was not
significantly different from that in control group (P=0.30). The quality of
included articles reached moderate-low level. In conclusion, citicolne cannot
reduce long-term mortality and dependence rate in the treatment of acute stroke,
and the effective rate of citivoline may be not better than that of controls but
with reliable safety. |
Is human lysyl oxidase-like 2 a glycoprotein? | Yes, human lysyl oxidase-like 2 is a glycoprotein. | Using recombit DNA technology for expression of protein therapeutics is a
maturing field of pharmaceutical research and development. As recombit
proteins are increasingly utilized as biotherapeutics, improved methodologies
ensuring the characterization of post-translational modifications (PTMs) are
needed. Typically, proteins prepared for PTM analysis are proteolytically
digested and analyzed by mass spectrometry. To ensure full coverage of the PTMs
on a given protein, one must obtain complete sequence coverage of the protein,
which is often quite challenging. The objective of the research described here
is to design a protocol that maximizes protein sequence coverage and enables
detection of post-translational modifications, specifically N-linked
glycosylation. To achieve this objective, a highly efficient proteolytic digest
protocol using trypsin was designed by comparing the relative merits of
denaturing agents (urea and Rapigest SF), reducing agents [dithiothreitol (DTT)
and tris(2-carboxyethyl)phophine (TCEP)], and various concentrations of
alkylating agent [iodoacetamide (IAM)]. After analysis of human apo-transferrin
using various protease digestion protocols, ideal conditions were determined to
contain 6 M urea for denaturation, 5 mM TCEP for reduction, 10 mM IAM for
alkylation, and 10 mM DTT, to quench excess IAM before the addition of trypsin.
This method was successfully applied to a novel recombit protein, human lysyl
oxidase-like 2. Furthermore, the glycosylation PTMs were readily detected at two
glycosylation sites in the protein. These digestion conditions were specifically
designed for PTM analysis of recombit proteins and biotherapeutics, and the
work described herein fills an unmet need in the growing field of
biopharmaceutical analysis. |
Can GDF15 be a biomarker for metformin treatment? | Yes, GDF15 levels are a biomarker for the use of metformin in people with dysglycemia, and its concentration reflects the dose of metformin. | OBJECTIVE: Metformin is a commonly used glucose-lowering drug. However, apart
from glycemic measures, no biomarker for its presence or dose has been
identified.
RESEARCH DESIGN AND METHODS: A total of 237 biomarkers were assayed in baseline
serum from 8,401 participants (2,317 receiving metformin) in the Outcome
Reduction with Initial Glargine Intervention (ORIGIN) trial. Regression models
were used to identify biomarkers for metformin use.
RESULTS: Growth differentiation factor 15 (GDF15) was strongly linked to
metformin, such that the odds of metformin use per SD increase in level varied
from 3.73 (95% CI 3.40, 4.09) to 3.94 (95% CI 3.59, 4.33) depending on the other
included variables. For the remaining 25 linked biomarkers, the odds ranged from
0.71 to 1.24. A 1.64 ng/mL higher GDF15 level predicted a 188-mg higher
metformin dose (P < 0.0001).
CONCLUSIONS: GDF15 levels are a biomarker for the use of metformin in people
with dysglycemia, and its concentration reflects the dose of metformin. |
Has rituximab been considered as a treatment for chronic fatigues syndrome? (November 2017) | The use of rituximab may be of benefit for CFS/ME, but the evidence of its effectiveness is still limited. | This review explores the current evidence on benefits and harms of therapeutic
interventions in chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) and
makes recommendations. CFS/ME is a complex, multi-system, chronic medical
condition whose pathophysiology remains unknown. No established diagnostic tests
exist nor are any FDA-approved drugs available for treatment. Because of the
range of symptoms of CFS/ME, treatment approaches vary widely. Studies
undertaken have heterogeneous designs and are limited by sample size, length of
follow-up, applicability and methodological quality. The use of rintatolimod and
rituximab as well as counselling, behavioural and rehabilitation therapy
programs may be of benefit for CFS/ME, but the evidence of their effectiveness
is still limited. Similarly, adaptive pacing appears to offer some benefits, but
the results are debatable: so is the use of nutritional supplements, which may
be of value to CFS/ME patients with biochemically proven deficiencies. To
summarize, the recommended treatment strategies should include proper
administration of nutritional supplements in CFS/ME patients with demonstrated
deficiencies and personalized pacing programs to relieve symptoms and improve
performance of daily activities, but a larger randomized controlled trial (RCT)
evaluation is required to confirm these preliminary observations. At present, no
firm conclusions can be drawn because the few RCTs undertaken to date have been
small-scale, with a high risk of bias, and have used different case definitions.
Further, RCTs are now urgently needed with rigorous experimental designs and
appropriate data analysis, focusing particularly on the comparison of outcomes
measures according to clinical presentation, patient characteristics, case
criteria and degree of disability (i.e. severely ill ME cases or bedridden). |
Does oncogene-induced DNA replication stress inhibit genomic instability? | No, oncogene-induced DNA replication stress is thought to drive genomic instability. | Oncogene-induced DNA replication stress is thought to drive genomic instability
in cancer. In particular, replication stress can explain the high prevalence of
focal genomic deletions mapping within very large genes in human tumors.
However, the origin of single-nucleotide substitutions (SNS) in nonfamilial
cancers is strongly debated. Some argue that cancers have a mutator phenotype,
whereas others argue that the normal DNA replication error rates are sufficient
to explain the number of observed SNSs. Here, we sequenced the exomes of 24,
mostly precancerous, colon polyps. Analysis of the sequences revealed mutations
in the APC, CTNNB1, and BRAF genes as the presumptive cancer-initiating events
and many passenger SNSs. We used the number of SNSs in the various lesions to
calculate mutation rates for normal colon and adenomas and found that colon
adenomas exhibit a mutator phenotype. Interestingly, the SNSs in the adenomas
mapped more often than expected within very large genes, where focal deletions
in response to DNA replication stress also map. We propose that single-stranded
DNA generated in response to oncogene-induced replication stress compromises the
repair of deaminated cytosines and other damaged bases, leading to the observed
SNS mutator phenotype. |
Is the petrous bone used in ancient DNA sampling? | Large-scale genomic analyses of ancient human populations have become feasible partly due to refined sampling methods. The inner part of petrous bones and the cementum layer in teeth roots are currently recognized as the best substrates for such research. | Large-scale genomic analyses of ancient human populations have become feasible
partly due to refined sampling methods. The inner part of petrous bones and the
cementum layer in teeth roots are currently recognized as the best substrates
for such research. We present a comparative analysis of DNA preservation in
these two substrates obtained from the same human skulls, across a range of
different ages and preservation environments. Both substrates display
significantly higher endogenous DNA content (average of 16.4% and 40.0% for
teeth and petrous bones, respectively) than parietal skull bone (average of
2.2%). Despite sample-to-sample variation, petrous bone overall performs better
than tooth cementum (p = 0.001). This difference, however, is driven largely by
a cluster of viking skeletons from one particular locality, showing relatively
poor molecular tooth preservation (<10% endogenous DNA). In the remaining
skeletons there is no systematic difference between the two substrates. A crude
preservation (good/bad) applied to each sample prior to DNA-extraction predicted
the above/below 10% endogenous DNA threshold in 80% of the cases. Interestingly,
we observe signficantly higher levels of cytosine to thymine deamination damage
and lower proportions of mitochondrial/nuclear DNA in petrous bone compared to
tooth cementum. Lastly, we show that petrous bones from ancient cremated
individuals contain no measurable levels of authentic human DNA. Based on these
findings we discuss the pros and cons of sampling the different elements. The temporal bone discovered in the 1960s from the Darra-i-Kur cave in
Afghanistan is often cited as one of the very few Pleistocene human fossils from
Central Asia. Here we report the first direct radiocarbon date for the specimen
and the genetic analyses of DNA extracted and sequenced from two areas of the
bone. The new radiocarbon determination places the find to ∼4500 cal BP (∼2500
BCE) contradicting an assumed Palaeolithic age of ∼30,000 years, as originally
suggested. The DNA retrieved from the specimen originates from a male individual
who carried mitochondrial DNA of the modern human type. The petrous part yielded
more endogenous ancient DNA molecules than the squamous part of the same bone.
Molecular dating of the Darra-i-Kur mitochondrial DNA sequence corroborates the
radiocarbon date and suggests that the specimen is younger than previously
thought. Taken together, the results consolidate the fact that the human bone is
not associated with the Pleistocene-age deposits of Darra-i-Kur; instead it is
intrusive, possibly re-deposited from upper levels dating to much later periods
(Neolithic). Despite its Holocene age, the Darra-i-Kur specimen is, so far, the
first and only ancient human from Afghanistan whose DNA has been sequenced. Ancient DNA (aDNA) research involves invasive and destructive sampling
procedures that are often incompatible with anthropological, anatomical, and
bioarcheological analyses requiring intact skeletal remains. The osseous
labyrinth inside the petrous bone has been shown to yield higher amounts of
endogenous DNA than any other skeletal element; however, accessing this
labyrinth in cases of a complete or reconstructed skull involves causing major
structural damage to the cranial vault or base. Here, we describe a novel
cranial base drilling method (CBDM) for accessing the osseous labyrinth from the
cranial base that prevents damaging the surrounding cranial features, making it
highly complementary to morphological analyses. We assessed this method by
comparing the aDNA results from one petrous bone processed using our novel
method to its pair, which was processed using established protocols for sampling
disarticulated petrous bones. We show a decrease in endogenous DNA and molecular
copy numbers when the drilling method is used; however, we also show that this
method produces more endogenous DNA and higher copy numbers than any postcranial
bone. Our results demonstrate that this minimally-invasive method reduces the
loss of genetic data associated with the use of other skeletal elements and
enables the combined craniometric and genetic study of individuals with
archeological, cultural, and evolutionary value. |
Is recursive splicing more common in short introns? | Recent work in human and fruitfly tissues revealed that long introns are extensively processed cotranscriptionally and in a stepwise manner, before their two flanking exons are spliced together Recursive splicing is a process in which large introns are removed in multiple steps by re-splicing at ratchet points--5' splice sites recreated after splicing. | RGS proteins are defined by the presence of a semiconserved RGS domain that
confers the GTPase-activating activity of these proteins toward certain G alpha
subunits. RGS6 is a member of a subfamily of RGS proteins distinguished by the
presence of DEP and GGL domains, the latter a G beta 5-interacting domain. Here
we report identification of 36 distinct transcripts of human RGS6 that arise by
unusually complex processing of the RGS6 gene, which spans 630 kilobase pairs of
genomic DNA in human chromosome 14 and is interrupted by 19 introns. These
transcripts arise by use of two alternative transcription sites and complex
alternative splicing mechanisms and encode proteins with long or short
N-terminal domains, complete or incomplete GGL domains, 7 distinct C-terminal
domains and a common internal domain where the RGS domain is found. The role of
structural diversity in the N-terminal and GGL domains of RGS6 splice variants
in their interaction with G beta 5 and subcellular localization and of G beta 5
on RGS6 protein localization was examined in COS-7 cells expressing various RGS6
splice variant proteins. RGS6 splice variants with complete GGL domains
interacted with G beta 5, irrespective of the type of N-terminal domain, while
those lacking a complete GGL domain did not. RGS6 protein variants displayed
subcellular distribution patterns ranging from an exclusive cytoplasmic to
exclusive nuclear/nucleolar localization, and co-expression of G beta 5 promoted
nuclear localization of RGS6 proteins. Analysis of our results show that the
long N-terminal and GGL domain sequences of RGS6 proteins function as
cytoplasmic retention sequences to prevent their nuclear/nucleolar accumulation.
These findings provide the first evidence for G beta 5-independent functions of
the GGL domain and for a role of G beta 5 in RGS protein localization. This
study reveals extraordinary complexity in processing of the human RGS6 gene and
provides new insights into how structural diversity in the RGS6 protein family
is involved in their localization and likely function(s) in cells. Many genes with important roles in development and disease contain exceptionally
long introns, but special mechanisms for their expression have not been
investigated. We present bioinformatic, phylogenetic, and experimental evidence
in Drosophila for a mechanism that subdivides many large introns by recursive
splicing at nonexonic elements and alternative exons. Recursive splice sites
predicted with highly stringent criteria are found at much higher frequency than
expected in the sense strands of introns >20 kb, but they are found only at the
expected frequency on the antisense strands, and they are underrepresented
within introns <10 kb. The predicted sites in long introns are highly conserved
between Drosophila melanogaster and Drosophila pseudoobscura, despite extensive
divergence of other sequences within the same introns. These patterns of
enrichment and conservation indicate that recursive splice sites are
advantageous in the context of long introns. Experimental analyses of in vivo
processing intermediates and lariat products from four large introns in the
unrelated genes kuzbanian, outspread, and Ultrabithorax confirmed that these
introns are removed by a series of recursive splicing steps using the predicted
nonexonic sites. Mutation of nonexonic site RP3 within Ultrabithorax also
confirmed that recursive splicing is the predomit processing pathway even
with a shortened version of the intron. We discuss currently known and potential
roles for recursive splicing. In the alternative splicing, intron retention, of histamine H(3) receptors in
rats and mice, the short transcript isoforms that are excised alternatively
spliced introns are easily detected in a very low level in rats and are
undetectable in mice using the regular PCR protocol. The retained introns have
common 5' splice site and different 3' splice sites. The detailed mechanism for
the special alternative splicing remains largely unclear. In this study, we
developed a minigene splicing system to recapitulate natural alternative
splicing of the receptors and investigated the effects of 5' and 3' splice sites
on intron retention in HeLa cells. Mutating weak 5' and 3' splice sites of the
alternatively spliced introns toward the canonical consensus sequences promoted
the splicing of the corresponding introns in rat and mouse minigenes. The effect
of splice site strength was context-dependent and much more significant for the
3' splice site of the longer alternative intron than for the 3' splice site of
the shorter alternative intron and the common 5' splice sites; it was also more
significant in the rat minigene than in the mouse minigene. Mutating the 3'
splice site of the longer alternative intron resulted in almost complete
splicing of the intron and made the corresponding isoform to become the nearly
exclusive transcript in the rat minigene. In mammals a considerable 92% of genes contain introns, with hundreds and
hundreds of these introns reaching the incredible size of over 50,000
nucleotides. These "large introns" must be spliced out of the pre-mRNA in a
timely fashion, which involves bringing together distant 5' and 3' acceptor and
donor splice sites. In invertebrates, especially Drosophila, it has been shown
that larger introns can be spliced efficiently through a process known as
recursive splicing-a consecutive splicing from the 5'-end at a series of
combined donor-acceptor splice sites called RP-sites. Using a computational
analysis of the genomic sequences, we show that vertebrates lack the proper
enrichment of RP-sites in their large introns, and, therefore, require some
other method to aid splicing. We analyzed over 15,000 non-redundant, large
introns from six mammals, 1,600 from chicken and zebrafish, and 560
non-redundant large introns from five invertebrates. Our bioinformatic
investigation demonstrates that, unlike the studied invertebrates, the studied
vertebrate genomes contain consistently abundant amounts of direct and
complementary strand interspersed repetitive elements (mainly SINEs and LINEs)
that may form stems with each other in large introns. This examination showed
that predicted stems are indeed abundant and stable in the large introns of
mammals. We hypothesize that such stems with long loops within large introns
allow intron splice sites to find each other more quickly by folding the
intronic RNA upon itself at smaller intervals and, thus, reducing the distance
between donor and acceptor sites. Recursive splicing is a process in which large introns are removed in multiple
steps by re-splicing at ratchet points--5' splice sites recreated after
splicing. Recursive splicing was first identified in the Drosophila
Ultrabithorax (Ubx) gene and only three additional Drosophila genes have since
been experimentally shown to undergo recursive splicing. Here we identify 197
zero nucleotide exon ratchet points in 130 introns of 115 Drosophila genes from
total RNA sequencing data generated from developmental time points, dissected
tissues and cultured cells. The sequential nature of recursive splicing was
confirmed by identification of lariat introns generated by splicing to and from
the ratchet points. We also show that recursive splicing is a constitutive
process, that depletion of U2AF inhibits recursive splicing, and that the
sequence and function of ratchet points are evolutionarily conserved in
Drosophila. Finally, we identify four recursively spliced human genes, one of
which is also recursively spliced in Drosophila. Together, these results
indicate that recursive splicing is commonly used in Drosophila, occurs in
humans, and provides insight into the mechanisms by which some large introns are
removed. It is generally believed that splicing removes introns as single units from
precursor messenger RNA transcripts. However, some long Drosophila melanogaster
introns contain a cryptic site, known as a recursive splice site (RS-site), that
enables a multi-step process of intron removal termed recursive splicing. The
extent to which recursive splicing occurs in other species and its mechanistic
basis have not been examined. Here we identify highly conserved RS-sites in
genes expressed in the mammalian brain that encode proteins functioning in
neuronal development. Moreover, the RS-sites are found in some of the longest
introns across vertebrates. We find that vertebrate recursive splicing requires
initial definition of an 'RS-exon' that follows the RS-site. The RS-exon is then
excluded from the domit mRNA isoform owing to competition with a
reconstituted 5' splice site formed at the RS-site after the first splicing
step. Conversely, the RS-exon is included when preceded by cryptic promoters or
exons that fail to reconstitute an efficient 5' splice site. Most RS-exons
contain a premature stop codon such that their inclusion can decrease mRNA
stability. Thus, by establishing a binary splicing switch, RS-sites demarcate
different mRNA isoforms emerging from long genes by coupling cryptic elements
with inclusion of RS-exons. Over time eukaryotic genomes have evolved to host genes carrying multiple exons
separated by increasingly larger intronic, mostly non-protein-coding, sequences.
Initially, little attention was paid to these intronic sequences, as they were
considered not to contain regulatory information. However, advances in molecular
biology, sequencing, and computational tools uncovered that numerous segments
within these genomic elements do contribute to the regulation of gene
expression. Introns are differentially removed in a cell type-specific manner to
produce a range of alternatively-spliced transcripts, and many span tens to
hundreds of kilobases. Recent work in human and fruitfly tissues revealed that
long introns are extensively processed cotranscriptionally and in a stepwise
manner, before their two flanking exons are spliced together. This process,
called "recursive splicing," often involves non-canonical splicing elements
positioned deep within introns, and different mechanisms for its deployment have
been proposed. Still, the very existence and widespread nature of recursive
splicing offers a new regulatory layer in the transcript maturation pathway,
which may also have implications in human disease. |
Is Lysyl oxidase crosslinking collagen? | Yes, lysyl oxidase (LOX) and LOX-like (LOXL) proteins play crucial roles in ECM remodeling due to their collagen crosslinking and intracellular functions. | Lung cancer is the leading cause of cancer-related deaths, primarily due to
distant metastatic disease. Metastatic lung cancer cells can undergo an
epithelial-to-mesenchymal transition (EMT) regulated by various transcription
factors, including a double-negative feedback loop between the microRNA-200
(miR-200) family and ZEB1, but the precise mechanisms by which ZEB1-dependent
EMT promotes maligcy remain largely undefined. Although the cell-intrinsic
effects of EMT are important for tumor progression, the reciprocal dynamic
crosstalk between mesenchymal cancer cells and the extracellular matrix (ECM) is
equally critical in regulating invasion and metastasis. Investigating the
collaborative effect of EMT and ECM in the metastatic process reveals increased
collagen deposition in metastatic tumor tissues as a direct consequence of
amplified collagen gene expression in ZEB1-activated mesenchymal lung cancer
cells. In addition, collagen fibers in metastatic lung tumors exhibit greater
linearity and organization as a result of collagen crosslinking by the lysyl
oxidase (LOX) family of enzymes. Expression of the LOX and LOXL2 isoforms is
directly regulated by miR-200 and ZEB1, respectively, and their upregulation in
metastatic tumors and mesenchymal cell lines is coordinated to that of collagen.
Functionally, LOXL2, as opposed to LOX, is the principal isoform that crosslinks
and stabilizes insoluble collagen deposition in tumor tissues. In turn, focal
adhesion formation and FAK/SRC signaling is activated in mesenchymal tumor cells
by crosslinked collagen in the ECM. Our study is the first to validate direct
regulation of LOX and LOXL2 by the miR-200/ZEB1 axis, defines a novel mechanism
driving tumor metastasis, delineates collagen as a prognostic marker, and
identifies LOXL2 as a potential therapeutic target against tumor progression. BACKGROUND/AIMS: We studied the role of lysyl oxidase-like 2 (LOXL2) in collagen
crosslinking and hepatic progenitor cell (HPC) differentiation, and the
therapeutic efficacy of a LOXL2-blocking monoclonal antibody on liver fibrosis
progression/reversal in mice.
METHODS: Anti-LOXL2 antibody, control antilysyl oxidase antibody or placebo was
administered during thioacetamide (TAA)-induced fibrosis progression or during
recovery. Therapeutic efficacy in biliary fibrosis was tested in BALB/c.Mdr2-/-
and 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC)-fed mice. Collagen
crosslinking, fibrosis progression and reversal were assessed histologically and
biochemically. HPC differentiation was studied in primary EpCAM(+) liver cells
in vitro.
RESULTS: LOXL2 was virtually absent from healthy but strongly induced in
fibrotic liver, with predomit localisation within fibrotic septa. Delayed
anti-LOXL2 treatment of active TAA fibrosis significantly reduced collagen
crosslinking and histological signs of bridging fibrosis, with a 53% reduction
in morphometric collagen deposition. In established TAA fibrosis, LOXL2
inhibition promoted fibrosis reversal, with enhanced splitting and thinning of
fibrotic septa, and a 45% decrease in collagen area at 4 weeks of recovery. In
the Mdr2-/- and DDC-induced models of biliary fibrosis, anti-LOXL2 antibody
similarly achieved significant antifibrotic efficacy and suppressed the ductular
reaction, while hepatocyte replication increased. Blocking LOXL2 had a profound
direct effect on primary EpCAM(+) HPC behaviour in vitro, promoting their
differentiation towards hepatocytes, while inhibiting ductal cell lineage
commitment.
CONCLUSIONS: LOXL2 mediates collagen crosslinking and fibrotic matrix
stabilisation during liver fibrosis, and independently promotes fibrogenic HPC
differentiation. By blocking these two convergent profibrotic pathways,
therapeutic LOXL2 inhibition attenuates both parenchymal and biliary fibrosis
and promotes fibrosis reversal. PURPOSE: The zonule of Zinn (ciliary zonule) is a system of fibers that centers
the crystalline lens on the optical axis of the eye. Mutations in zonule
components underlie syndromic conditions associated with a broad range of ocular
pathologies, including microspherophakia and ectopia lentis. Here, we used
HPLC-mass spectrometry to determine the molecular composition of the zonule.
METHODS: Tryptic digests of human and bovine zonular samples were analyzed by
HPLC-mass spectrometry. The distribution of selected components was confirmed by
immunofluorescence confocal microscopy. In bovine samples, the composition of
the equatorial zonule was compared to that of the hyaloid zonule and vitreous
humor.
RESULTS: The 52 proteins common to the zonules of both species accounted for
>95% of the zonular protein. Glycoproteins constituted the main structural
components, with two proteins, FBN1 and LTBP2, constituting 70%-80% of the
protein. Other abundant components were MFAP2, EMILIN-1, and ADAMTSL-6. Lysyl
oxidase-like 1, a crosslinking enzyme implicated in collagen and elastin
biogenesis, was detected at significant levels. The equatorial and hyaloid
zonular samples were compositionally similar to each other, although the hyaloid
sample was relatively enriched in the proteoglycan opticin and the fibrillar
collagens COL2A1, COL11A1, COL5A2, and COL5A3.
CONCLUSIONS: The zonular proteome was surprisingly complex. In addition to
structural components, it contained signaling proteins, protease inhibitors, and
crosslinking enzymes. The equatorial and hyaloid zonules were similar in
composition, but the latter may form part of a composite structure, the hyaloid
membrane, that stabilizes the vitreous face. |
Is sternotomy closure done using either a sternal ZipFix™ implant or conventional steel wire following cardiac surgery? | Yes, closure of the sternum following cardiac surgery can be done using a wire closure or sternal ZipFix™ a cable-tie-based system which is fast, easy to use, reliable and safe. | BACKGROUND: Sternal dehiscence occurs when steel wires pull through sternal
bone. This study tests the hypothesis that closure stability can be improved by
jacketing sternal wires with stainless steel coils, which distribute the force
exerted on the bone over a larger area.
METHODS: Midline sternotomies were performed in 6 human cadavers (4 male). Two
sternal closure techniques were tested: (1) approximation with six interrupted
wires, and (2) the same closure technique reinforced with 3.0-mm-diameter
stainless steel coils that jacket wires at the lateral and posterior aspects of
the sternum. Intrathoracic pressure was increased with an inflatable rubber
bladder placed beneath the anterior chest wall, and sternal separation was
measured by means of sonomicrometry crystals. In each trial, intrathoracic
pressure was increased until 2.0 mm of motion was detected. Differences in
displacement pressures between groups were examined at 0.25-mm intervals using
the paired Student's t test.
RESULTS: The use of coil-reinforced closures produced significant improvement in
sternal stability at all eight displacement levels examined (p < 0.03). Mean
pressure required to cause displacement increased 140% (15.5 to 37.3 mm Hg) at
0.25 mm of separation, 103% (34.3 to 69.8 mm Hg) at 1.0 mm of separation, and
122% (46.8 to 103.8 mm Hg) at 2.0 mm of separation.
CONCLUSIONS: Reinforcement of sternal wires with stainless steel coils
substantially improves stability of sternotomy closure in a human cadaver model. BACKGROUND: Wire closure still remains the preferred technique despite
reasonable disadvantages. Associated complications, such as infection and
sternal instability, cause time- and cost-consuming therapies. We present a new
tool for sternal closure with its first clinical experience and results.
METHODS: The sternal ZipFix(TM) System is based on the cable-tie principle. It
primarily consists of biocompatible Poly-Ether-Ether-Ketone implants and is
predomitly used peristernally through the intercostal space. The system
provides a large implant-to-bone contact for better force distribution and for
avoiding bone cut through.
RESULTS: 50 patients were closed with the ZipFix(TM) system. No sternal
instability was observed at 30 days. Two patients developed a mediastinitis that
necessitated the removal of the device; however, the ZipFix(TM) were intact and
the sternum remained stable.
CONCLUSIONS: In our initial evaluation, the short-term results have shown that
the sternal ZipFix(TM) can be used safely and effectively. It is fast, easy to
use and serves as a potential alternative for traditional wire closure. OBJECTIVES: To determine the difference in sternal infection and other
infectious events between conventional wire and cable-tie-based closure
techniques post-sternotomy in a collective of patients after cardiac surgery.
METHODS: The sternal ZipFix™ (ZF) system consists of a biocompatible
poly-ether-ether-ketone (PEEK) cable-tie that surrounds the sternum through the
intercostal space and provides a large implant-to-bone contact. Between 1
February 2011 and 31 January 2012, 680 cardiac operations were performed via
sternotomy at our institution. After the exclusion of operations for active
endocarditis and early mortality within 7 days, 95 patients were exclusively
closed with ZF and could be compared with 498 who were closed with conventional
wires (CWs) during the same period. A multivariable logistic regression
analysis, including body mass index, renal impairment and emergency as suspected
confounders and inverse propensity weights was performed on the infection rate.
RESULTS: Total infection rate was 6.1%, with a total of 36 diagnosed sternal
infections (5 in ZF and 31 in CW). Comparing ZF with CW with regard to sternal
infection, there is no statistically significant difference related to the
device (odds ratio: 0.067, confidence interval: 0.04-9.16, P=0.72). The
propensity modelling provided excellent overlap and the mean propensity was
almost the same in both groups. Thus, we have observed no difference in
receiving either ZF or CW. No sternal instability was observed with the ZF
device, unlike 4/31 patients in the CW group. The overall operation time is
reduced by 11 min in the ZF group with identical perfusion and clamping times.
CONCLUSIONS: Our study underlines a neutral effect of the sternal ZipFix™ system
in patients regarding sternal infection. Postoperative complications are similar
in both sternal closure methods. The cable-tie-based system is fast, easy to
use, reliable and safe. BACKGROUND: Stainless steel wiring remains the most popular technique for
primary sternal closure. Recently, a multifilament cable wiring system (Pioneer
Surgical Technology Inc., Marquette, MI, USA) was introduced for sternal closure
and has gained wide acceptance due to its superior resistance to tension. We
aimed to compare conventional steel wiring to multifilament cable fixation for
sternal closure in patients undergoing major cardiac surgery.
METHODS: Data were collected retrospectively on 1,354 patients who underwent
sternal closure after major cardiac surgery, using either the multifilament
cable wiring system or conventional steel wires between January 2009 and October
2010. The surgical outcomes of these two groups of patients were compared using
propensity score matching based on 18 baseline patient characteristics.
RESULTS: Propensity score matching yielded 392 pairs of patients in the two
groups whose baseline profiles showed no significant differences. No significant
differences between the two groups were observed in the rates of early mortality
(2.0% vs. 1.3%, p=0.578), major wound complications requiring reconstruction
(1.3% vs. 1.3%, p>0.99), minor wound complications (3.6% vs. 2.0%, p=0.279), or
mediastinitis (0.8% vs. 1.0%, p=1.00). Patients in the multifilament cable group
had fewer sternal bleeding events than those in the conventional wire group, but
this tendency was not statistically significant (4.3% vs. 7.4%, p=0.068).
CONCLUSION: The surgical outcomes of sternal closure using multifilament cable
wires were comparable to those observed when conventional steel wires were used.
Therefore, the multifilament cable wiring system may be considered a viable
option for sternal closure in patients undergoing major cardiac surgery. |
Is transcription of eRNA bidirectional? | In addition to widespread transcription of long non-coding RNAs (lncRNAs) in mammalian cells, bidirectional ncRNAs are transcribed on enhancers, and are thus referred to as enhancer RNAs (eRNAs). Kallikrein-related peptidase 3 (KLK3), which codes for prostate-specific antigen (PSA), is a well-known AR-regulated gene and its upstream enhancers produce bidirectional enhancer RNAs (eRNAs), termed KLK3e. | We have integrated and analyzed a large number of data sets from a variety of
genomic assays using a novel computational pipeline to provide a global view of
estrogen receptor 1 (ESR1; a.k.a. ERα) enhancers in MCF-7 human breast cancer
cells. Using this approach, we have defined a class of primary transcripts
(eRNAs) that are transcribed uni- or bidirectionally from estrogen receptor
binding sites (ERBSs) with an average transcription unit length of ∼3-5 kb. The
majority are up-regulated by short treatments with estradiol (i.e., 10, 25, or
40 min) with kinetics that precede or match the induction of the target genes.
The production of eRNAs at ERBSs is strongly correlated with the enrichment of a
number of genomic features that are associated with enhancers (e.g., H3K4me1,
H3K27ac, EP300/CREBBP, RNA polymerase II, open chromatin architecture), as well
as enhancer looping to target gene promoters. In the absence of eRNA production,
strong enrichment of these features is not observed, even though ESR1 binding is
evident. We find that flavopiridol, a CDK9 inhibitor that blocks transcription
elongation, inhibits eRNA production but does not affect other molecular
indicators of enhancer activity, suggesting that eRNA production occurs after
the assembly of active enhancers. Finally, we show that an enhancer
transcription "signature" based on GRO-seq data can be used for de novo enhancer
prediction across cell types. Together, our studies shed new light on the
activity of ESR1 at its enhancer sites and provide new insights about enhancer
function. The functional importance of gene enhancers in regulated gene expression is well
established. In addition to widespread transcription of long non-coding RNAs
(lncRNAs) in mammalian cells, bidirectional ncRNAs are transcribed on enhancers,
and are thus referred to as enhancer RNAs (eRNAs). However, it has remained
unclear whether these eRNAs are functional or merely a reflection of enhancer
activation. Here we report that in human breast cancer cells 17β-oestradiol
(E2)-bound oestrogen receptor α (ER-α) causes a global increase in eRNA
transcription on enhancers adjacent to E2-upregulated coding genes. These
induced eRNAs, as functional transcripts, seem to exert important roles for the
observed ligand-dependent induction of target coding genes, increasing the
strength of specific enhancer-promoter looping initiated by ER-α binding.
Cohesin, present on many ER-α-regulated enhancers even before ligand treatment,
apparently contributes to E2-dependent gene activation, at least in part by
stabilizing E2/ER-α/eRNA-induced enhancer-promoter looping. Our data indicate
that eRNAs are likely to have important functions in many regulated programs of
gene transcription. The androgen receptor (AR) is a key factor that regulates the behavior and fate
of prostate cancer cells. The AR-regulated network is activated when AR binds
enhancer elements and modulates specific enhancer-promoter looping.
Kallikrein-related peptidase 3 (KLK3), which codes for prostate-specific antigen
(PSA), is a well-known AR-regulated gene and its upstream enhancers produce
bidirectional enhancer RNAs (eRNAs), termed KLK3e. Here, we demonstrate that
KLK3e facilitates the spatial interaction of the KLK3 enhancer and the KLK2
promoter and enhances long-distance KLK2 transcriptional activation. KLK3e
carries the core enhancer element derived from the androgen response element III
(ARE III), which is required for the interaction of AR and Mediator 1 (Med1).
Furthermore, we show that KLK3e processes RNA-dependent enhancer activity
depending on the integrity of core enhancer elements. The transcription of KLK3e
was detectable and its expression is significantly correlated with KLK3 (R(2) =
0.6213, P < 5 × 10(-11)) and KLK2 (R(2) = 0.5893, P < 5 × 10(-10)) in human
prostate tissues. Interestingly, RNAi silencing of KLK3e resulted in a modest
negative effect on prostate cancer cell proliferation. Accordingly, we report
that an androgen-induced eRNA scaffolds the AR-associated protein complex that
modulates chromosomal architecture and selectively enhances AR-dependent gene
expression. Author information:
(1)1] CGAT Programme, MRC Functional Genomics Unit, Department of Physiology,
Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK [2].
(2)1] Department of Pharmacy and Pharmacology, University of Bath, Claverton
Down, BA2 7AY Bath, UK [2].
(3)Department of Pharmacy and Pharmacology, University of Bath, Claverton Down,
BA2 7AY Bath, UK.
(4)Respiratory Research Group, University Hospital of South Manchester,
University of Manchester, Southmoor Road, Manchester M23 9LY, UK.
(5)Airways Disease, National Heart and Lung Institute, Imperial College, London
SW3 6LY, UK.
(6)Department of Functional and Comparative Genomics, Centre for Genomic
Research, University of Liverpool, Liverpool L69 3BX, UK.
(7)CGAT Programme, MRC Functional Genomics Unit, Department of Physiology,
Anatomy, and Genetics, University of Oxford, Oxford OX1 3QX, UK.
(8)1] Department of Pharmacy and Pharmacology, University of Bath, Claverton
Down, BA2 7AY Bath, UK [2] Respiratory Research Group, University Hospital of
South Manchester, University of Manchester, Southmoor Road, Manchester M23 9LY,
UK [3] Airways Disease, National Heart and Lung Institute, Imperial College,
London SW3 6LY, UK. Recent studies have revealed that active enhancers are transcribed, producing a
class of noncoding RNAs called enhancer RNAs (eRNAs). eRNAs are distinct from
long noncoding RNAs (lncRNAs), but these two species of noncoding RNAs may share
a similar role in the activation of mRNA transcription. Emerging studies,
showing that eRNAs function in controlling mRNA transcription, challenge the
idea that enhancers are merely sites of transcription factor assembly. Instead,
communication between promoters and enhancers can be bidirectional with
promoters required to activate enhancer transcription. Reciprocally, eRNAs may
then facilitate enhancer-promoter interaction or activate promoter-driven
transcription. A new paradigm has emerged in recent years characterizing transcription
initiation as a bidirectional process encompassing a larger proportion of the
genome than previously thought. Past concepts of coding genes thinly scattered
among a vast background of transcriptionally inert noncoding DNA have been
abandoned. A richer picture has taken shape, integrating transcription of coding
genes, enhancer RNAs (eRNAs), and various other noncoding transcriptional
events. In this review we give an overview of recent studies detailing the
mechanisms of RNA polymerase II (RNA Pol II)-based transcriptional initiation
and discuss the ways in which transcriptional direction is established as well
as its functional implications. |
Is the protein pelota a ribosomal rescue factor? | Yes, in eukaryotes, Pelota (Dom34 in yeast) and Hbs1 are responsible for solving general problems of ribosomal stall in translation. | No-go decay and nonstop decay are mRNA surveillance pathways that detect
translational stalling and degrade the underlying mRNA, allowing the correct
translation of the genetic code. In eukaryotes, the protein complex of Pelota
(yeast Dom34) and Hbs1 translational GTPase recognizes the stalled ribosome
containing the defective mRNA. Recently, we found that archaeal Pelota (aPelota)
associates with archaeal elongation factor 1α (aEF1α) to act in the mRNA
surveillance pathway, which accounts for the lack of an Hbs1 ortholog in
archaea. Here we present the complex structure of aPelota and GTP-bound aEF1α
determined at 2.3-Å resolution. The structure reveals how GTP-bound aEF1α
recognizes aPelota and how aPelota in turn stabilizes the GTP form of aEF1α.
Combined with the functional analysis in yeast, the present results provide
structural insights into the molecular interaction between eukaryotic Pelota and
Hbs1. Strikingly, the aPelota·aEF1α complex structurally resembles the
tRNA·EF-Tu complex bound to the ribosome. Our findings suggest that the
molecular mimicry of tRNA in the distorted "A/T state" conformation by Pelota
enables the complex to efficiently detect and enter the empty A site of the
stalled ribosome. In higher eukaryotes, transfer RNAs (tRNAs) with the same anticodon are encoded
by multiple nuclear genes, and little is known about how mutations in these
genes affect translation and cellular homeostasis. Similarly, the surveillance
systems that respond to such defects in higher eukaryotes are not clear. Here,
we discover that loss of GTPBP2, a novel binding partner of the ribosome
recycling protein Pelota, in mice with a mutation in a tRNA gene that is
specifically expressed in the central nervous system causes ribosome stalling
and widespread neurodegeneration. Our results not only define GTPBP2 as a
ribosome rescue factor but also unmask the disease potential of mutations in
nuclear-encoded tRNA genes. |
Is CXCL7 a chemokine? | Yes, CXCL7 is a chemokine highly expressed in platelets. | CXCL7, a chemokine highly expressed in platelets, orchestrates neutrophil
recruitment during thrombosis and related pathophysiological processes by
interacting with CXCR2 receptor and sulfated glycosaminoglycans (GAG). CXCL7
exists as monomers and dimers, and dimerization (~50 μM) and CXCR2 binding (~10
nM) constants indicate that CXCL7 is a potent agonist as a monomer. Currently,
nothing is known regarding the structural basis by which receptor and GAG
interactions mediate CXCL7 function. Using solution nuclear magnetic resoce
(NMR) spectroscopy, we characterized the binding of CXCL7 monomer to the CXCR2
N-terminal domain (CXCR2Nd) that constitutes a critical docking site and to GAG
heparin. We found that CXCR2Nd binds a hydrophobic groove and that ionic
interactions also play a role in mediating binding. Heparin binds a set of
contiguous basic residues indicating a prominent role for ionic interactions.
Modeling studies reveal that the binding interface is dynamic and that GAG
adopts different binding geometries. Most importantly, several residues involved
in GAG binding are also involved in receptor interactions, suggesting that
GAG-bound monomer cannot activate the receptor. Further, this is the first study
that describes the structural basis of receptor and GAG interactions of a native
monomer of the neutrophil-activating chemokine family. Chemokines mediate diverse fundamental biological processes, including combating
infection. Multiple chemokines are expressed at the site of infection; thus
chemokine synergy by heterodimer formation may play a role in determining
function. Chemokine function involves interactions with G-protein-coupled
receptors and sulfated glycosaminoglycans (GAG). However, very little is known
regarding heterodimer structural features and receptor and GAG interactions.
Solution nuclear magnetic resoce (NMR) and molecular dynamics
characterization of platelet-derived chemokine CXCL7 heterodimerization with
chemokines CXCL1, CXCL4, and CXCL8 indicated that packing interactions promote
CXCL7-CXCL1 and CXCL7-CXCL4 heterodimers, and electrostatic repulsive
interactions disfavor the CXCL7-CXCL8 heterodimer. As characterizing the native
heterodimer is challenging due to interference from monomers and homodimers, we
engineered a "trapped" disulfide-linked CXCL7-CXCL1 heterodimer. NMR and
modeling studies indicated that GAG heparin binding to the heterodimer is
distinctly different from the CXCL7 monomer and that the GAG-bound heterodimer
is unlikely to bind the receptor. Interestingly, the trapped heterodimer was
highly active in a Ca2+ release assay. These data collectively suggest that GAG
interactions play a prominent role in determining heterodimer function in vivo.
Further, this study provides proof-of-concept that the disulfide trapping
strategy can serve as a valuable tool for characterizing the structural and
functional features of a chemokine heterodimer. |
The TRPM2 gene is associated with development of spontaneous thromboembolism? | TheTransientReceptorPotentialMelastatin 2 (TRPM2) is a member of G protein coupled receptor superfamily and a novel dual-function protein that possesses both ion channel andAdenosine 5'-DiphosPhataseRibose (ADPR) hydrolase function. TRPM2 is involved in Ca2+signaling in various cells as an endogenous redox sensor for oxidative stress and reactive oxygen species, and contributes to cytokine production, insulin release, motility, Ca2+entry and Ca2+-dependent cellular reactions such as endothelial hyper-permeability and apoptosis and may regulate the bacteriocidal activity of Macrophages | TRPM2 is a recently identified TRPM family cation channel which is unique among
known ion channels in that it contains a C-terminal domain which is homologous
to the NUDT9 ADP-ribose hydrolase and possesses intrinsic ADP-ribose hydrolase
activity. Here, available information on the TRPM2 gene, transcripts, predicted
protein products, and assembled multimeric channels is comprehensively reviewed
and synthesized to highlight important areas for future work and provide insight
into potential biological function(s) of TRPM2 channels. It has been proposed that in cancer, where the bulk of the genome becomes
hypomethylated, there is an increase in transcriptional noise that might lead to
the generation of antisense transcripts that could affect the function of key
oncosuppressor genes, ultimately leading to maligt transformation. Here, we
describe the computational identification of a melanoma-enriched antisense
transcript, TRPM2-AS, mapped within the locus of TRPM2, an ion channel capable
of mediating susceptibility to cell death. Analysis of the TRPM2-AS genomic
region indicated the presence in the same region of another tumor-enriched TRPM2
transcript, TRPM2-TE, located across a CpG island shared with TRPM2-AS.
Quantitative PCR experiments confirmed that TRPM2-AS and TRPM2-TE transcripts
were up-regulated in melanoma, and their activation was consistent with the
methylation status of the shared CpG island. Functional knock-out of TRPM2-TE,
as well as over-expression of wild-type TRPM2, increased melanoma susceptibility
to apoptosis and necrosis. Finally, expression analysis in other cancer types
indicated that TRPM2-AS and TRPM2-TE over-expression might have an even wider
role than anticipated, reinforcing the relevance of our computational approach
in identifying new potential therapeutic targets. BACKGROUND: Disordered cellular calcium regulation has been implicated in the
pathophysiology of diabetes through mechanisms that remain unresolved. The
non-selective calcium channel, transient receptor potential cation channel,
subfamily M, member 2 (TRPM2), has been recently reported to play a role in
insulin secretion by pancreatic beta-cells. We hypothesized that gene variation
of TRPM2 may play a role in the pathophysiology of type 2 diabetes mellitus
(T2DM).
METHODS: Using a case-control study from a community-based population sample of
the Boston metropolitan area (all whites: 455 controls and 467 cases), we
assessed the relationship of 9 TRPM2 tag-SNPs with (i) diabetes-related
intermediate phenotypes and (ii) the presence of T2DM.
RESULT: All SNPs examined were in Hardy-Weinberg equilibrium. Overall allele,
genotype, and haplotype distributions were similar between cases and controls.
Three TRPM2 variants (rs2838553, rs2838554 and rs4818917) were associated with
homeostasis model assessment of beta-cell function (HOMA-%B), but not with
HOMA-insulin resistance (HOMA-IR), fasting glucose levels nor hemoglobin A1c
levels. Marker-by-marker logistic regression analysis, adjusted for potential
risk factors, showed no evidence for an association of any of the tag-SNPs
tested with T2DM. Further investigation using an entropy blocker-defined
haplotype-based approach showed similar null findings.
CONCLUSIONS: The present investigation found no evidence for an association of
the variants tested with T2DM, although HOMA-%B was negatively associated with
three TRPM2 variants (rs2838553, rs2838554 and rs4818917). More importantly, our
present findings require replication/confirmation in future large-scale,
prospective investigations. The Na+ and Ca(2+)-permeable melastatin related transient receptor potential 2
(TRPM2) channels can be gated either by ADP-ribose (ADPR) in concert with Ca(2+)
or by hydrogen peroxide (H(2)O(2)), an experimental model for oxidative stress,
binding to the channel's enzymatic Nudix domain. Since the mechanisms that lead
to TRPM2 gating in response to ADPR and H(2)O(2) are not understood in neuronal
cells, I summarized previous findings and important recent advances in the
understanding of Ca(2+) influx via TRPM2 channels in different neuronal cell
types and disease processes. Considering that TRPM2 is activated by oxidative
stress, mediated cell death and inflammation, and is highly expressed in brain,
the channel has been investigated in the context of central nervous system.
TRPM2 plays a role in H(2)O(2) and amyloid β-peptide induced striatal cell
death. Genetic variants of the TRPM2 gene confer a risk of developing Western
Pacific amyotropic lateral sclerosis and parkinsonism-dementia complex and
bipolar disorders. TRPM2 also contributes to traumatic brain injury processes
such as oxidative stress, inflammation and neuronal death. There are a limited
number of TRPM2 channel blockers and they seem to be cell specific. For example,
ADPR-induced Ca(2+) influx in rat hippocampal cells was not blocked by
N-(p-amylcinnomoyl)anthralic acid (ACA), the IP(3) receptor inhibitor
2-aminoethoxydiphenyl borate or PLC inhibitor flufenamic acid (FFA). However,
the Ca(2+) entry in rat primary striatal cells was blocked by ACA and FFA. In
conclusion TRPM2 channels in neuronal cells can be gated by either ADPR or
H(2)O(2). It seems to that the exact relationship between TRPM2 channels
activation and neuronal cell death still remains to be determined. BACKGROUND: There is strong evidence that oxidative stress is associated with
the pathogenesis of chronic obstructive pulmonary disease (COPD). The transient
receptor potential melastatin-2 (TRPM2) is an oxidative stress sensing channel
that is expressed in a number of inflammatory cells and therefore it has been
suggested that inhibition of TRPM2 could lead to a beneficial effect in COPD
patients. In this study, we have investigated the role of TRPM2 in a variety of
mouse models of oxidative stress and COPD using TRPM2-deficent mice.
METHODS: Mice were exposed to ozone (3 ppm for 4 h) or lipopolysaccharide (LPS,
0.3 mg/kg, intranasaly). In another model, mice were exposed to tobacco smoke
(750 μg/l total wet particulate matter) for 30 min twice a day on three
consecutive days. For the exacerbation model, the smoke exposure on the morning
of day 3 animals was replaced with intranasal administration of LPS (0.3 mg/kg).
Animals were killed 3 and 24 h after the challenge (ozone and LPS model) or 18 h
after the last tobacco smoke exposure. In vitro neutrophil chemotaxis and
monocyte activation were also studied using cells isolated from wild type and
TRPM2-deficient animals. Statistical significance for the in vivo data (P <
0.05) was determined using analysis of variance with Kruskal-Wallis and Dunns
multiple comparison test.
RESULTS: In all models studied, no difference in the bronchoalveolar lavage
inflammation could be evidenced when comparing wild type and TRPM2-deficient
mice. In addition, no difference could be seen in the lung inflammation as
assessed by the measurement of various cytokines/chemokines. Similarly in
various in vitro cellular activation assays using isolated neutrophils and
monocytes no significant differences could be observed when comparing wild type
and TRPM2-deficient mice.
DISCUSSION: We have shown, in all the models tested, no difference in the
development of airway inflammation or cell activation between TRPM2-deficient
mice and their wild type counterparts. These results would suggest that
inhibiting TRPM2 activity in COPD would have no anti-inflammatory effect. BACKGROUND: Glutathione (GSH) plays an important role in neuronal oxidant
defence. Depletion of cellular GSH is observed in neurodegenerative diseases and
thereby contributes to the associated oxidative stress and Ca2+ dysregulation.
Whether depletion of cellular GSH, associated with neuronal senescence, directly
influences Ca2+ permeation pathways is not known. Transient receptor potential
melastatin type 2 (TRPM2) is a Ca2+ permeable non-selective cation channel
expressed in several cell types including hippocampal pyramidal neurons.
Moreover, activation of TRPM2 during oxidative stress has been linked to cell
death. Importantly, GSH has been reported to inhibit TRPM2 channels, suggesting
they may directly contribute to Ca2+ dysregulation associated with neuronal
senescence. Herein, we explore the relation between cellular GSH and TRPM2
channel activity in long-term cultures of hippocampal neurons.
RESULTS: In whole-cell voltage-clamp recordings, we observe that TRPM2 current
density increases in cultured pyramidal neurons over time in vitro. The observed
increase in current density was prevented by treatment with NAC, a precursor to
GSH synthesis. Conversely, treatment of cultures maintained for 2 weeks in vitro
with L-BSO, which depletes GSH by inhibiting its synthesis, augments TRPM2
currents. Additionally, we demonstrate that GSH inhibits TRPM2 currents through
a thiol-independent mechanism, and produces a 3.5-fold shift in the
dose-response curve generated by ADPR, the intracellular agonist for TRPM2.
CONCLUSION: These results indicate that GSH plays a physiologically relevant
role in the regulation of TRPM2 currents in hippocampal pyramidal neurons. This
interaction may play an important role in aging and neurological diseases
associated with depletion of GSH. AIMS: Transient receptor potential melastatin 2 (TRPM2) highly expressed in
immunocytes is a Ca(2+)-permeable non-selective cation channel activated by
oxidative stress. Myocardial ischaemia/reperfusion (I/R) injury is characterized
by acute inflammation associated with the augmentation of oxidative stress. We
hypothesized that TRPM2 is implicated in the exacerbation of myocardial I/R
injury.
METHODS AND RESULTS: Wild-type (Trpm2(+/+)) and Trpm2 knockout (Trpm2(-/-)) mice
were subjected to ligation of the left main coronary artery followed by
reperfusion. Myocardial infarction following I/R, but not ischaemia alone, was
reduced more in Trpm2(-/-)mice than in Trpm2(+/+) mice and cardiac contractile
functions were also improved in Trpm2(-/-)mice. TRPM2 was highly expressed in
the polymorphonuclear leucocytes (PMNs) rather than in the heart. The number of
neutrophils and myeloperoxidase (MPO) activity in the reperfused area following
ischaemia was lowered in Trpm2(-/-) mice. When Trpm2(+)(/+) or Trpm2(-/-) PMNs
were administered to the Trpm2(-/-) heart ex vivo through the perfusate or in
vivo by iv injection, Trpm2(+)(/+) PMNs produced enlargement of the infarct
size. Following in vitro regional I/R, a pharmacological inhibitor of TRPM2
reduced the infarct size. The combination of H(2)O(2) and leukotriene B(4)
(LTB(4)) increased intracellular Ca(2+) concentration and their adhesion to
endothelial cells in Trpm2(+)(/+) but not in Trpm2(-/-)PMNs.
CONCLUSION: These findings indicate that neutrophil TRPM2 is implicated in the
exacerbation of myocardial reperfusion injury. Accumulation of neutrophils in
the reperfused area mediated by TRPM2 activation is likely to play a crucial
role in myocardial I/R injury. Food allergy (FA) is a common allergic disease without any currently available
effective drug therapies. Mucosal mast cells (MMCs) play a particularly
important role in FA, and the increase in their cytosolic Ca(2+) concentration
([Ca(2+)]cyt) is considered to be a principal component of the degranulation
process. However, the mechanisms governing Ca(2+) influx remain poorly
understood in MMCs. Recent reports have highlighted the functions of the
transient receptor potential melastatin 2 (TRPM2) channel in immunocytes,
including its role in monocyte chemokine production and macrophage phagocytic
activity. Although TRPM2 gene expression has been demonstrated in mast cells,
the significance of such expression remains virtually unknown. In this study, we
found that antigen-stimulated degranulation was significantly reduced in
mucosal-type bone marrow-derived mast cells (mBMMCs) prepared from
TRPM2-knockout (TRPM2-KO) mice (TRPM2-KO mBMMCs) and was suppressed following
the administration of three TRPM2 inhibitors with different chemical structures,
including econazole, flufenamic acid (FFA), and 2-aminoethoxydiphenyl borate.
Furthermore, the antigen-stimulated increase in [Ca(2+)]cyt was significantly
decreased in TRPM2-KO mBMMCs and was also suppressed by the TRPM2 inhibitors
econazole and FFA. In addition, thapsigargin-induced increase in [Ca(2+)]cyt was
significantly decreased in TRPM2-KO mBMMCs. These results suggest that TRPM2 may
participate in antigen-induced extracellular Ca(2+) influx and subsequent
degranulation. In addition, TRPM2 inhibitors were shown to improve food allergic
reactions in a mouse model. Together, these results suggest that TRPM2
inhibitors suppress MMC degranulation via regulation of the increase in
[Ca(2+)]cyt. Thus, TRPM2 may play a key role in degranulation by modulating
intracellular Ca(2+) in MMCs. BACKGROUND AND PURPOSE: Brain injury during stroke results in oxidative stress
and the release of factors that include extracellular Ca(2+), hydrogen peroxide,
adenosine diphosphate ribose, and nicotinic acid adenine dinucleotide phosphate.
These alterations of the extracellular milieu change the activity of transient
receptor potential melastatin subfamily member 2 (TRPM2), a nonselective cation
channel expressed in the central nervous system and the immune system. Our goal
was to evaluate the contribution of TRPM2 to the tissue damage after stroke.
METHODS: In accordance with current quality guidelines, we independently
characterized Trpm2 in a murine ischemic stroke model in 2 different
laboratories.
RESULTS: Gene deficiency of Trpm2 resulted in significantly improved
neurological outcome and decreased infarct size. Besides an already known
moderate neuroprotective effect of Trpm2 deficiency in vitro, ischemic brain
invasion by neutrophils and macrophages was particularly reduced in
Trpm2-deficient mice. Bone marrow chimeric mice revealed that Trpm2 deficiency
in the peripheral immune system is responsible for the protective phenotype.
Furthermore, experiments with mixed bone marrow chimeras demonstrated that Trpm2
is essential for the migration of neutrophils and, to a lesser extent, also of
macrophages into ischemic hemispheres. Notably, the pharmacological TRPM2
inhibitor, N-(p-amylcinnamoyl)anthranilic acid, was equally protective in the
stroke model.
CONCLUSIONS: Although a neuroprotective effect of TRPM2 in vitro is well known,
we can show for the first time that the detrimental role of TRPM2 in stroke
primarily depends on its role in activating peripheral immune cells. Targeting
TRPM2 systemically represents a promising therapeutic approach for ischemic
stroke. In Alzheimer's disease, accumulation of soluble oligomers of β-amyloid peptide
is known to be highly toxic, causing disturbances in synaptic activity and
neuronal death. Multiple studies relate these effects to increased oxidative
stress and aberrant activity of calcium-permeable cation channels leading to
calcium imbalance. The transient receptor potential melastatin 2 (TRPM2)
channel, a Ca(2+)-permeable nonselective cation channel activated by oxidative
stress, has been implicated in neurodegenerative diseases, and more recently in
amyloid-induced toxicity. Here we show that the function of TRPM2 is augmented
by treatment of cultured neurons with β-amyloid oligomers. Aged APP/PS1
Alzheimer's mouse model showed increased levels of endoplasmic reticulum stress
markers, protein disulfide isomerase and phosphorylated eukaryotic initiation
factor 2α, as well as decreased levels of the presynaptic marker synaptophysin.
Elimination of TRPM2 in APP/PS1 mice corrected these abnormal responses without
affecting plaque burden. These effects of TRPM2 seem to be selective for
β-amyloid toxicity, as ER stress responses to thapsigargin or tunicamycin in
TRPM2(-/-) neurons was identical to that of wild-type neurons. Moreover, reduced
microglial activation was observed in TRPM2(-/-)/APP/PS1 hippocampus compared
with APP/PS1 mice. In addition, age-dependent spatial memory deficits in APP/PS1
mice were reversed in TRPM2(-/-)/APP/PS1 mice. These results reveal the
importance of TRPM2 for β-amyloid neuronal toxicity, suggesting that TRPM2
activity could be potentially targeted to improve outcomes in Alzheimer's
disease.
SIGNIFICANCE STATEMENT: Transient receptor potential melastatin 2 (TRPM2) is an
oxidative stress sensing calcium-permeable channel that is thought to contribute
to calcium dysregulation associated with neurodegenerative diseases, including
Alzheimer's disease. Here we show that oligomeric β-amyloid, the toxic peptide
in Alzheimer's disease, facilitates TRPM2 channel activation. In mice designed
to model Alzheimer's disease, genetic elimination of TRPM2 normalized deficits
in synaptic markers in aged mice. Moreover, the absence of TRPM2 improved
age-dependent spatial memory deficits observed in Alzheimer's mice. Our results
reveal the importance of TRPM2 for neuronal toxicity and memory impairments in
an Alzheimer's mouse model and suggest that TRPM2 could be targeted for the
development of therapeutic agents effective in the treatment of dementia. Transient receptor potential melastatin 2 (TRPM2) is a thermosensitive,
Ca2+-permeable cation channel. TRPM2 contributes to the pathogenesis of
inflammatory bowel disease, and inflammatory and neuropathic pain. We
hypothesized that TRPM2 is important for visceral nociception and the
development of visceral hypersensitivity. Therefore, we investigated the
expression of TRPM2 channels and their involvement in visceral nociception in
normal physiology and under pathological conditions that cause visceral
hypersensitivity in rats. TRPM2 immunoreactivities were detected in the mucosa
and muscle layer of the rat gastrointestinal tract. TRPM2 immunopositive cell
bodies were almost completely co-localized with calretinin- and NeuN-positive
cells in the myenteric plexus. We found that the majority of the
TRPM2-immunoreactive cells were double-labeled with the retrograde marker
fluorogold in lumbar 6/sacral 1 dorsal root ganglia (DRG), indicating that TRPM2
is expressed in spinal primary afferents innervating the distal colon. Subtypes
of TRPM2-immunopositive DRG neurons were labeled by the A-fiber marker NF200,
the C-fiber marker IB4, substance P, calcitonin gene-related peptide, or P2X3
receptor. We found that oral administration of the TRPM2 inhibitor econazole
(30mg/kg) reduced the visceromotor response (VMR) to noxious colorectal
distention (CRD) at 80mmHg in control rats. Expression of TRPM2 in the mucosa of
the distal colon was increased in a trinitrobenzene sulfonic acid-induced
colitis model. The VMR to CRD significantly increased in colitis model rats
compared with control rats at 40, 60, and 80mmHg. Econazole restored visceral
hypersensitivity to the control level. Furthermore, TRPM2-deficient mice showed
significantly attenuated trinitrobenzene sulfonic acid induced visceral
hypersensitivity compared with wild-type mice. In conclusion, TRPM2 channels
contribute to visceral nociception in response to noxious stimuli under normal
conditions and visceral hypersensitivity in pathological conditions. Acidification of macrophage phagosomes serves an important bactericidal
function. We show here that the redox-sensitive transient receptor potential
(TRP) cation channel TRPM2 is expressed in the phagosomal membrane and regulates
macrophage bactericidal activity through the activation of phagosomal
acidification. Measurement of the TRPM2 current in phagosomes identified TRPM2
as a functional redox-sensitive cation channel localized in the phagosomal
membrane. Simultaneous measurements of phagosomal Ca2+ changes and phagosome
acidification in macrophages undergoing phagocytosis demonstrated that TRPM2 was
required to mediate the efflux of cations and for phagosomal acidification
during the process of phagosome maturation. Acidification in phagosomes was
significantly reduced in macrophages isolated from Trpm2-/- mice as compared to
wild type, and acidification was coupled to reduced bacterial clearance in
Trpm2-/- mice. Trpm2+/+ macrophages treated with the vacuolar H+-ATPase
inhibitor bafilomycin showed reduced bacterial clearance, similar to that in
Trpm2-/- macrophages. Direct activation of TRPM2 using adenosine diphosphate
ribose (ADPR) induced both phagosomal acidification and bacterial killing. These
data collectively demonstrate that TRPM2 regulates phagosomal acidification, and
is essential for the bacterial killing function of macrophages. The Transient Receptor Potential Melastatin 2 (TRPM2) is a member of G protein
coupled receptor superfamily and a novel dual-function protein that possesses
both ion channel and Adenosine 5'-DiphosPhatase Ribose (ADPR) hydrolase
function. TRPM2 is involved in Ca2+ signaling in various cells as an endogenous
redox sensor for oxidative stress and reactive oxygen species, and contributes
to cytokine production, insulin release, motility, Ca2+ entry and Ca2+-dependent
cellular reactions such as endothelial hyper-permeability and apoptosis. The
wide expression of TRPM2 might render it as a potentially significant
therapeutic target in pathological settings including cardiovascular and
neurodegenerative diseases and of great relevance in drug design, feed additives
and other industries. Here, we discuss the TRPM2 gene structure, function, its
variants, as well as its activators and inhibitors and provide a peptide drug
design for modulation of oxidative stress. Trisomy 21 (Down Syndrome, DS) is the most common chromosomal anomaly. Although
DS is mostly perceived as affecting cognitive abilities and cardiac health,
individuals with DS also exhibit dysregulated immune functions. Levels of
pro-inflammatory cytokines are increased, but intrinsic alterations of innate
immunity are understudied in DS. Furthermore, elevated Reactive Oxygen Species
(ROS) are well documented in individuals with DS, further exacerbating
inflammatory processes. Chronic inflammation and oxidative stress are often
precursors of subsequent tissue destruction and pathologies, which affect a
majority of persons with DS. Together with ROS, the second messenger ion Ca2+
plays a central role in immune regulation. TRPM2 (Transient Receptor Potential
Melastatin 2) is a Ca2+-permeable ion channel that is activated under conditions
of oxidative stress. The Trpm2 gene is located on human Chromosome 21 (Hsa21).
TRPM2 is strongly represented in innate immune cells, and numerous studies have
documented its role in modulating inflammation. We have previously found that as
a result of suboptimal cytokine production, TRPM2-/- mice are highly susceptible
to the bacterial pathogen Listeria monocytogenes (Lm). We therefore used Lm
infection to trigger and characterize immune responsiveness in the DS mouse
model Dp10(yey), and to investigate the potential contribution of TRPM2. In
comparison to wildtype (WT), Dp10(yey) mice show an increased resistance against
Lm infection and higher IFNγ serum concentrations. Using a gene elimination
approach, we show that these effects correlate with Trpm2 gene copy number,
supporting the notion that Trpm2 might promote hyperinflammation in DS. |
Is a mutation of the ZIKV's membrane protein prM responsible for the microcephaly in new-born infants? | Yes, a single mutation in the prM protein of Zika virus contributes to fetal microcephaly. | Author information:
(1)State Key Laboratory of Molecular Developmental Biology, Chinese Academy of
Sciences (CAS) Center for Excellence in Brain Science and Intelligence
Technology, Institute of Genetics and Developmental Biology, CAS, Beijing
100101, China.
(2)University of CAS, Beijing 100101, China.
(3)Department of Virology, State Key Laboratory of Pathogen and Biosecurity,
Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
(4)State Key Laboratory of Stem Cell and Reproductive Biology, Institute of
Zoology, CAS, Beijing 100101, China.
(5)Graduate School, Anhui Medical University, Hefei 230032, China.
(6)National Laboratory of Macromolecules, Institute of Biophysics, CAS, Beijing
100101, China.
(7)Shandong Universities Key Laboratory of Etiology and Epidemiology of Emerging
Infectious Diseases, Taishan Medical College, Taian 271000, China.
(8)Department of Biochemistry and Molecular Biology and Department of
Pharmacology and Toxicology, Sealy Center for Structural Biology and Molecular
Biophysics, University of Texas Medical Branch, Galveston, TX 77555, USA.
(9)Parkinson's Disease Center, Beijing Institute for Brain Disorders, Beijing
100101, China. |
What is the aim of the PhenCode database? | PhenCode (Phenotypes for ENCODE; http://www.bx.psu.edu/phencode) is a collaborative, exploratory project to help understand phenotypes of human mutations in the context of sequence and functional data from genome projects. | PhenCode (Phenotypes for ENCODE; http://www.bx.psu.edu/phencode) is a
collaborative, exploratory project to help understand phenotypes of human
mutations in the context of sequence and functional data from genome projects.
Currently, it connects human phenotype and clinical data in various
locus-specific databases (LSDBs) with data on genome sequences, evolutionary
history, and function from the ENCODE project and other resources in the UCSC
Genome Browser. Initially, we focused on a few selected LSDBs covering genes
encoding alpha- and beta-globins (HBA, HBB), phenylalanine hydroxylase (PAH),
blood group antigens (various genes), androgen receptor (AR), cystic fibrosis
transmembrane conductance regulator (CFTR), and Bruton's tyrosine kinase (BTK),
but we plan to include additional loci of clinical importance, ultimately
genomewide. We have also imported variant data and associated OMIM links from
Swiss-Prot. Users can find interesting mutations in the UCSC Genome Browser (in
a new Locus Variants track) and follow links back to the LSDBs for more detailed
information. Alternatively, they can start with queries on mutations or
phenotypes at an LSDB and then display the results at the Genome Browser to view
complementary information such as functional data (e.g., chromatin modifications
and protein binding from the ENCODE consortium), evolutionary constraint,
regulatory potential, and/or any other tracks they choose. We present several
examples illustrating the power of these connections for exploring phenotypes
associated with functional elements, and for identifying genomic data that could
help to explain clinical phenotypes. For development and evaluation of methods for predicting the effects of
variations, benchmark datasets are needed. Some previously developed datasets
are available for this purpose, but newer and larger benchmark sets for benign
variants have largely been missing. VariSNP datasets are selected from dbSNP.
These subsets were filtered against disease-related variants in the ClinVar,
UniProtKB/Swiss-Prot, and PhenCode databases, to identify neutral or
nonpathogenic cases. All variant descriptions include mapping to reference
sequences on chromosomal, genomic, coding DNA, and protein levels. The datasets
will be updated with automated scripts on a regular basis and are freely
available at http://structure.bmc.lu.se/VariSNP. |
What is the basis of the Sp3 procedure used in proteomics? | SP3, a novel technology for proteomic sample preparation using magnetic beads. SP3 provides a rapid and unbiased means of proteomic sample preparation in a single tube that facilitates ultrasensitive analysis by outperforming existing protocols in terms of efficiency, scalability, speed, throughput, and flexibility. | In order to obtain a systems-level understanding of a complex biological system,
detailed proteome information is essential. Despite great progress in proteomics
technologies, thorough interrogation of the proteome from quantity-limited
biological samples is hampered by inefficiencies during processing. To address
these challenges, here we introduce a novel protocol using paramagnetic beads,
termed Single-Pot Solid-Phase-enhanced Sample Preparation (SP3). SP3 provides a
rapid and unbiased means of proteomic sample preparation in a single tube that
facilitates ultrasensitive analysis by outperforming existing protocols in terms
of efficiency, scalability, speed, throughput, and flexibility. To illustrate
these benefits, characterization of 1,000 HeLa cells and single Drosophila
embryos is used to establish that SP3 provides an enhanced platform for
profiling proteomes derived from sub-microgram amounts of material. These data
present a first view of developmental stage-specific proteome dynamics in
Drosophila at a single-embryo resolution, permitting characterization of
inter-individual expression variation. Together, the findings of this work
position SP3 as a superior protocol that facilitates exciting new directions in
multiple areas of proteomics ranging from developmental biology to clinical
applications. Oocytes undergo a range of complex processes via oogenesis, maturation,
fertilization, and early embryonic development, eventually giving rise to a
fully functioning organism. To understand proteome composition and diversity
during maturation of human oocytes, here we have addressed crucial aspects of
oocyte collection and proteome analysis, resulting in the first proteome and
secretome maps of human oocytes. Starting from 100 oocytes collected via a novel
serum-free hanging drop culture system, we identified 2,154 proteins, whose
function indicate that oocytes are largely resting cells with a proteome that is
tailored for homeostasis, cellular attachment, and interaction with its
environment via secretory factors. In addition, we have identified 158
oocyte-enriched proteins (such as ECAT1, PIWIL3, NLRP7)(1) not observed in
high-coverage proteomics studies of other human cell lines or tissues.
Exploiting SP3, a novel technology for proteomic sample preparation using
magnetic beads, we scaled down proteome analysis to single cells. Despite the
low protein content of only ∼100 ng per cell, we consistently identified ∼450
proteins from individual oocytes. When comparing individual oocytes at the
germinal vesicle (GV) and metaphase II (MII) stage, we found that the Tudor and
KH domain-containing protein (TDRKH) is preferentially expressed in immature
oocytes, while Wee2, PCNA, and DNMT1 were enriched in mature cells, collectively
indicating that maintece of genome integrity is crucial during oocyte
maturation. This study demonstrates that an innovative proteomics workflow
facilitates analysis of single human oocytes to investigate human oocyte biology
and preimplantation development. The approach presented here paves the way for
quantitative proteomics in other quantity-limited tissues and cell types. Data
associated with this study are available via ProteomeXchange with identifier
PXD004142. |
What is "enhancer hijacking"? | Enhancer hijacking is the molecular process through which a structural variant removes or moves a TAD boundary to expose TSSs to regulatory enhancers from which they would normally be insulated. | B-cell lymphomas frequently contain genomic rearrangements that lead to oncogene
activation by heterologous distal regulatory elements. We used a novel approach
called "pinpointing enhancer-associated rearrangements by chromatin
immunoprecipitation," or PEAR-ChIP, to simultaneously map enhancer activity and
proximal rearrangements in lymphoma cell lines and patient biopsies. This method
detects rearrangements involving known cancer genes, including CCND1, BCL2, MYC,
PDCD1LG2, NOTCH1, CIITA, and SGK1, as well as novel enhancer duplication events
of likely oncogenic significance. We identify lymphoma subtype-specific
enhancers in the MYC locus that are silenced in lymphomas with MYC-activating
rearrangements and are associated with germline polymorphisms that alter
lymphoma risk. We show that BCL6-locus enhancers are acetylated by the
BCL6-activating transcription factor MEF2B, and can undergo genomic duplication,
or target the MYC promoter for activation in the context of a
"pseudo-double-hit" t(3;8)(q27;q24) rearrangement linking the BCL6 and MYC loci.
Our work provides novel insights regarding enhancer-driven oncogene activation
in lymphoma.
SIGNIFICANCE: We demonstrate a novel approach for simultaneous detection of
genomic rearrangements and enhancer activity in tumor biopsies. We identify
novel mechanisms of enhancer-driven regulation of the oncogenes MYC and BCL6,
and show that the BCL6 locus can serve as an enhancer donor in an "enhancer
hijacking" translocation. Author information:
(1)European Molecular Biology Laboratory (EMBL), Genome Biology Unit,
Heidelberg, Germany.
(2)The Finsen Laboratory, Rigshospitalet, University of Copenhagen, Copenhagen,
Denmark.
(3)Biotech Research and Innovation Centre (BRIC), Copenhagen, Denmark.
(4)Department of Translational Oncology, National Center for Tumor Diseases
(NCT), Heidelberg, Germany.
(5)Division of Translational Oncology, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(6)Division of Molecular Thoracic Oncology, German Cancer Research Center
(DKFZ), Heidelberg, Germany.
(7)Department of Translational Genomics, Center of Integrated Oncology
Cologne-Bonn, Medical Faculty, University of Cologne, Cologne, Germany.
(8)Department of Cancer Genetics, Institute for Cancer Research, Oslo University
Hospital-The Norwegian Radium Hospital, Oslo, Norway.
(9)Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(10)Division of Clinical Epidemiology and Aging Research, German Cancer Research
Center (DKFZ), Heidelberg, Germany.
(11)Department of Oncology, Oslo University Hospital-The Norwegian Radium
Hospital, Oslo, Norway.
(12)Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis,
Tennessee, USA.
(13)Institute of Pathology, Jena University Hospital, Jena, Germany.
(14)General Surgery, Heidelberg University Clinics, Heidelberg, Germany.
(15)Department of Cardiothoracic Surgery, Oslo University
Hospital-Rikshospitalet, Oslo, Norway.
(16)Department of Pathology, VU University Medical Center, Amsterdam, the
Netherlands.
(17)Institute of Pathology, Technical University Munich, Munich, Germany.
(18)Department of Pathology, University Hospital Cologne, Cologne, Germany.
(19)German Consortium for Translational Cancer Research (DKTK), German Cancer
Research Center (DKFZ), Heidelberg, Germany.
(20)Center for Molecular Medicine Cologne (CMMC), University of Cologne,
Cologne, Germany.
(21)European Molecular Biology Laboratory (EMBL), Cell Biology Unit, Heidelberg,
Germany.
(22)European Molecular Biology Laboratory-European Bioinformatics Institute
(EMBL-EBI), Wellcome Trust Genome Campus, Cambridge, UK. Author information:
(1)Division of Pediatric Neurooncology, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(2)Department of Developmental Neurobiology, St Jude Children's Research
Hospital, Memphis, Tennessee, USA.
(3)Division of Theoretical Bioinformatics, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(4)Division of Applied Bioinformatics, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(5)Department for Bioinformatics and Functional Genomics, Institute for Pharmacy
and Molecular Biotechnology (IPMB) and BioQuant, Heidelberg University,
Heidelberg, Germany.
(6)Developmental &Stem Cell Biology Program, The Hospital for Sick Children,
Toronto, Ontario.
(7)Division of Molecular Genetics, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(8)Biotech Research &Innovation Centre (BRIC), Copenhagen University and Finsen
Laboratory, Rigshospitalet, Denmark.
(9)Department of Biological Engineering, Massachusetts Institute of Technology,
Cambridge, Massachusetts, USA.
(10)German Cancer Consortium (DKTK), Heidelberg, Germany.
(11)Genome Biology Unit, European Molecular Biology Laboratory (EMBL),
Heidelberg, Germany.
(12)Max Planck Institute for Molecular Genetics, Department of Vertebrate
Genomics, Berlin, Germany.
(13)Department of Structural Biology, St Jude Children's Research Hospital,
Memphis, Tennessee, USA.
(14)Broad Institute of Harvard and MIT, Cambridge, Massachusetts, USA.
(15)Heidelberg Center for Personalized Oncology (DKFZ-HIPO), German Cancer
Research Center (DKFZ), Heidelberg, Germany.
(16)Medical Faculty Heidelberg, Heidelberg University, Heidelberg, Germany.
(17)Department of Pediatric Hematology and Oncology, Heidelberg University
Hospital, Heidelberg, Germany.
(18)Genomics and Proteomics Core Facility, German Cancer Research Center (DKFZ),
Heidelberg, Germany.
(19)Department of Oncology, St Jude Children's Research Hospital, Memphis,
Tennessee, USA.
(20)Department of Computational Biology, St Jude Children's Research Hospital,
Memphis, Tennessee, USA.
(21)Department of Oncogenomics, Amsterdam Medical Center, Amsterdam,
Netherlands.
(22)Department of Neuropathology, NN Burdenko Neurosurgical Institute, Moscow,
Russia.
(23)Department of Pediatrics, Papé Family Pediatric Research Institute, Knight
Cancer Institute, Oregon Health and Science University, Portland, Oregon, USA.
(24)Department of Neurology, Boston Children's Hospital and Harvard Medical
School, Boston, Massachusetts, USA.
(25)Department of Neurosurgery, University Clinic, Heidelberg University,
Heidelberg Hospital, Germany.
(26)Department of Neurosurgery, University Hospital Tübingen, Tübingen, Germany.
(27)Department of Hematology and Oncology, Children's University Hospital
Tübingen, Tübingen, Germany.
(28)Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los
Angeles, California, USA.
(29)Developmental Tumor Biology Laboratory, Hospital Sant Joan de Déu,
Barcelona, Spain.
(30)Department of Pathology, Duke University, Durham, North County, USA.
(31)Department of Pediatrics, McGill University, Montreal, Quebec, Canada.
(32)Department of Neurosurgery, Kitasato University School of Medicine,
Sagamihara, Japan.
(33)Michael Smith Genome Sciences Centre, BC Cancer Agency, Vancouver, British
Columbia, Canada.
(34)Department of Neuropathology, Heidelberg University Hospital, Heidelberg,
Germany.
(35)Division of Neurosurgery, Hospital for Sick Children, Toronto, Ontario,
Canada. |
What disease is tinea ? | Tinea is a superficial fungal infections of the skin. | 4103 cases suspected of mycoses were analysed as to sex, age and site of disease
and 3891 were proved cases. This group formed 50% of total mycoses or 13-93% of
all dermatoses recorded in the Government General Hospital, Madras, during the
period of study. There were 66-26% adult female, 27-6% adult male and 6-14% were
below 13 years. Dermatophytoses were found in 73-5%; the other common diseases
were tinea versicolor (17-68%) and candidiasis (12-43%). Multiple sites of
involvement or more than 1 disease in the same individual were mostly observed.
The incidence of piedra (0-1%) and deep mycoses (0-156%) was very low. Mycetoma
was the common disease (5/6) in deep mycoses. In dermatophytoses, tinea corporis
(49-71%) and tinea cruris (47-85%) commonest; tinea axillaris (3-42%), tinea
capitis (1-72%) and tinea barbae (1-29%) were less common. The incidence of
tinea manuum, tinea pedis and tinea unguium was similar (4-97%-6-38%). High
temperature and humidity were related to the higher incidence of tinea corporis,
tinea cruris and tinea versicolor. Mainly children suffered from tinea capitis.
All other mycoses were commonly found in adults between 2nd and 3rd decades. In
all mycoses but candidiasis, female predominated. Cutaneous candidiasis was
mainly a problem of housewives. Among the dermatophytes Trichophyton violaceum
was predomit (33-7%) followed by T. rubrum (32-6%). Trichophyton schoenleinii
and M. gypseum were rarely isolated. From mycetoma, Madurella mycetomii,
Nocardia braziliensis, N. asteroides and Actinomadura spp. were isolated.
Demonstration of Cryptococcus laurentii in 1 case is reported in this area for
the first time. Superficial fungal infections are common. Most diagnoses of fungal infections of
the skin can be made by physical examination, assisted by the use of a Wood's
lamp, skin scrapings for microscopic examination, and fungal cultures.
Dermatophyte infections are common at all ages, in both sexes, and they have a
worldwide distribution. These infections include tinea capitis, tinea cruris,
tinea pedis, tinea corporis, tinea manuum and tinea barbae. Tinea versicolor,
caused by Malassezia furfur, and candidal infections are also common. Treatment
modalities include oral and topical agents. Good personal hygiene is an
important adjunct to antifungal therapy. Decisions regarding the appropriateness
of therapy in a given patient must take into account the extent and location of
the infection, the benefits and risks of each of the treatments, and cost. Oral
therapies include griseofulvin, ketoconazole, and itraconazole. There are a
large variety of topical treatments, including nystatin, selenium sulfide,
tolnaftate, haloprogin, miconazole, clotrimazole, and sodium thiosulfate.
Important to successful treatment is compliance with what is sometimes a long
course of treatment, and good personal hygiene. BACKGROUND: Visceral leishmaniasis (VL) is endemic in several areas in the
Sudan. The disease is associated with depressed cellular immunity. Tinea
versicolor is a normal commensal of the skin which can become pathogenic
particularly in patients with depressed cell-mediated immunity. Patients with VL
have a high prevalence of tinea versicolor.
METHODS: One hundred and thirty patients with parasitologic confirmation of VL
were screened for tinea versicolor infection. In the suspected cases the
diagnosis was made by demonstrating the fungal hyphae and spores in skin
scrapings. All patients were treated with sodium stibogluconate.
RESULTS: Of the 130 patients with VL, 10.8% were found to have severe tinea
versicolor. The fungal infection developed or became worse with the start of VL.
After successful treatment of VL, the tinea lesions disappeared completely or
decreased in severity.
CONCLUSIONS: Depressed cell-mediated immunity that is a feature of VL is the
probable underlying cause for fungal infection. Tinea infection during the
course of VL is to be distinguished from lesions of post-kala-azar dermal
leishmaniasis. Superficial mycotic infections of the skin, hair, or nails are recurring
presentations in the geriatric primary care setting. The most common infections
are those caused by dermatophytes. The genus Trichophyton gives rise to most of
the tinea dermatophytoses, including tinea capitis, tinea pedis, and tinea
unguium (onychomycosis). Part of the diagnostic challenge lies in distinguishing
the mycotic lesions from those caused by cutaneous diseases such as psoriasis,
eczema, dyshidrosis, and contact dermatitis. Because environmental conditions
play a major role in fungal infection onset, clinical management should include
patient education about conditions conducive to fungal propagation. Oral agents
are the primary mode of treatment for fungal infections of the scalp and nails,
whereas topical treatments are frontline agents for other superficial skin
conditions. Tinea capitis is a dermatophyte infection that occurs mainly in childhood; there
are few reports, in Brazil, in adolescents and adults. The detection of
asymptomatic carriers is of great importance in the disease control. From
February 1998 to February 1999, a study was performed at the outpatient
Dermatologic Unit of Instituto de Puericultura e Pediatria Martagão Gesteira
(Universidade Federal do Rio de Janeiro, Brasil) to verify the frequency of
asymptomatic carriers and tinea capitis between 79 adolescents, adults and
elderly who lived in the same household of 56 children (0-12 years) with tinea
capitis. Of these, one female and one male adults (2.5%) were asymptomatic
carriers and the cultures revealed Trichophyton tonsurans and Microsporum canis
respectively. One female adolescent and two female adults (3.8%) had tinea
capitis and all cultures revealed Trichophyton tonsurans. The study has shown
that adolescents and adults who live in the same household of children with
tinea capitis may be sick or asymptomatic carriers. Tinea capitis is a fungal infection of the skin and the hair with involvement of
the hair shaft and the pilosebaceous unit. It may be the most common of all
cutaneous mycoses in children. Tinea capitis can be inflammatory or
noninflammatory. It is thought that humoral and cell-mediated immunities play a
role in the formation of the clinical types of the disease. We studied twelve
patients with acute inflammatory disease, four patients with chronic
non-inflammatory disease, and one patient with a black-dot variant of tinea
capitis. The composition of inflammatory infiltrates present in lesional skin
was analyzed by antibodies to T cells (CD3) and B cells (CD20). Anti-CD3
revealed large numbers of T cells in twelve patients with acute, inflammatory
dermatophytosis, whereas anti-CD20 revealed marked infiltrates of both B and T
cells in all patients with chronic, non-inflammatory dermatophytosis. As a
result, we thought that cell-mediated immunity might play a role in the acute,
inflammatory type of tinea capitis and that humoral immunity might do so in the
chronic, non-inflammatory type of tinea capitis. OBJECTIVE: To study the epidemiology of foot diseases, including tinea pedis and
onychomycosis in clinic attendees in Hong Kong.
METHODS: Two groups were included: the institutional group consisted of clinical
evaluation and mycological investigations by dermatologists; and the private
group consisted of clinical evaluation only by the private physicians. Patients
who had a regular visit to the clinics were randomly invited to have a clinical
examination of their feet.
RESULTS: A total of 1014 patients were studied. The prevalence rate of foot
disease, fungal infections, tinea pedis and toe nail onychomycosis were
respectively 50.7%, 26.9%, 20.4% and 16.6%. More male and elderly patients were
affected except that the sex prevalence in toe nail onychomycosis was not shown
to be significant. Vascular disease, diabetes mellitus and obesity were the
three most prevalent predisposing factors in foot disease, fungal disease and
fungal nail disease. Dermatophytes, in particular Trichophyton rubrum, were
shown to be the most common pathogen in both skin and nail infections.
CONCLUSIONS: Foot diseases, especially tinea pedis and toe nail onychomycosis,
are common in patients attending local clinics in Hong Kong. Both physicians and
patients should be more aware of foot problems and have more active approaches
and management strategies. The term "tinea incognita" refers to diverse clinical presentation of mycotic
infections modified by inappropriate use of topical or systemic corticosteroids.
A 67-year-old male patient with a five-year history of generalized erythematous
plaques on the trunk and extremities, previously treated with topical
corticosteroids, is described. The lesions mainly showed a psoriasiform, some
eczematous appearance, few of them showing a clinical picture of folliculitis.
The native mycologic specimen was negative. The diagnosis was made on the basis
of mycologic culture finding of Trichophyton interdigitale growth. Systemic and
topical antimycotic therapy administered for two months resulted in complete
regression of skin lesions. A statistical 30-year study of dermatomycosis in Sendai National Hospital
(1968-1997) revealed many changes in the prevalent diseases: Tinea pedis and
tinea unguium constantly increased during this period, and the ratio of the
former associated with nail infection finally reached 30% of all tinea pedis
patients. On the contrary, tinea corporis and cruris showed a remarkable
decreasing tendency. Patient age distribution of each disease also showed
distinctive changes, generally increasing in the older generation and decreasing
in the younger. The number of patients with tinea pedis and unguium gradually
increased among the middle and older generations, with the peak of the
age-distribution curve shifting upward year after year. On the other hand, cases
of tinea cruris among the younger generation were few in the latest years, and
middle-age patients remained at a low number. In the first stage of this study
the kinds of atiologic dermatophytes consisted of multiple species, but after
middle period the isolation of Epidermaphyton floccosum decreased. Microsporum
canis appeared first in 1976 but in the recent several years has completely
disappeared. In the last few years of the period studied Trichophyton rubrum and
Trichophyton mentagrophytes were the only isolates found from among all types of
dermatophytoses. Infantile candidiasis remarkably increased in 1970-1975 but
thereafter decreased rapidlly. Candidial intertrigo also increased in the same
period but did not decrease as much thereafter and continued at the same
intermediate level. The number of other types of candidiases were not greatly
changed throughout the 30-year period. Malassezia infection also showed no
remarkable changes, and only 20 cases of sporothrichosis were found. One case of
the deep seated form of cutaneous aspergillosis was found, and this was also
true of chromomycosis caused by Fonceaea pedrosoi. An estimated 4.2 million seasonal and migrant farmworkers and their dependents
live in the U.S. Most of these farmworkers are Latino. These workers are exposed
to numerous occupational and environmental risk factors that can result in skin
disease. Few data exist on the prevalence of skin disease in this population.
The purpose of this study was to estimate the prevalence and predictors of skin
disease in a sample of Latino farmworkers in North Carolina. A sample of 59
farmworkers was recruited and interviewed at two camps during the 2004
agricultural season. A dermatologist completed a skin exam of each worker and
recorded any skin disease present. Forty-two (77.7%) of the 54 men, and all five
of the women examined had a diagnosed skin disease. For the men, onychomycosis
(nail fungus, 31.5%), tinea pedis (foot fungus, 27.8%), and acne (24.1 %) were
the most commonly diagnosed skin diseases, with contact dermatitis diagnosed in
5.6% of the sample. Other diagnoses included scars, sunburn, and atopic
dermatitis. Among the women, diagnoses included melasma (dark patches on the
face, 2 cases), xerosis (excessively dry skin, 1 case), tinea pedis (2 cases),
onychomycosis (1 case), acne (1 case), and insect bites (1 case). There were no
statistically significant differences between workers in the two camps despite
different growing seasons and different crops harvested. Skin disease is
prevalent among the North Carolina Latino farmworkers who participated in this
study, with fungal disease being the most prevalent. The koranic schools are in poor socio-economical conditions in Dakar and skin
diseases are common in these conditions. The goal of our descriptive study was
to determine the prevalence of skin diseases occurring in these situations. One
hundred five boys from four koranic schools of Dakar were examined. Eighty
percent of the examined boys were with unless one skin disease. Tinea capitis
(42.66%), scabiosis (13.33%), pyoderma (15.33%), plantar keratodermia (100%)
were the skin diseases. In 34.52% these skin disease were associated and
antecedents of skin infections diseases were reported in 89.5% of boys. Atopic
dermatitis was in 2.38% cases, keloid in 1.19%. The other frequent diseases were
abdominal parasitosis (71.42%), umbilical hernia (6.66%). All skin diseases were
improved only in 50% of cases after two months of treatment. Tinea capitis was
cured in 4 months after treatment. The high prevalence and the chronicity of the
skin disease were due to poor socio-economical conditions. BACKGROUND: Although usually simple, the diagnosis of dermatophyte infection is
sometimes neglected. An observational study has been realized to evaluate the
role of corticosteroid exposure (tinea incognito) and of other primary
characteristics of the dermatophytosis that from onset mimic other diseases and
mislead an unexperienced physician.
MATERIALS AND METHODS: Between 1990 and 2009, all cases of atypical
dermatophytosis mimicking other skin diseases were collected from the more
general number of dermatophyte infections diagnosed at the Dermatology
Department of Cagliari University, Italy.
RESULTS: One-hundred and fifty-four cases (71 male/83 female, 2-81 years old)
were studied, with a median of 7 cases/year. The most observed clinical forms
were those mimicking impetigo, eczematous dermatitis, lupus erythematosus,
polymorphous light eruption, psoriasis, and rosacea. The identified
dermatophytes were: Microsporum canis (70 cases), Trichophyton rubrum (43
cases), Trichophyton mentagrophytes var. mentagrophytes (29 cases), Trichophyton
mentagrophytes var. interdigitale (six cases), Microsporum gypseum (three
cases), Epidermophyton floccosum (two cases), and Trichophyton verrucosum (one
case). Diagnostic difficulties are discussed, with special attention to the
origin of the pathomorphosis.
CONCLUSIONS: In our experience, clinical atypia is not a mere consequence of
corticosteroid therapy but present at the very onset of the illness, due to the
variable dermatophyte invasive capacity, the site of invasion, physiological
individual, and/or acquired condition, such as excessive washing or sun
exposure. Therefore, we suggest using the term "tinea atypica" rather than
"tinea incognito" to include all forms of dermatophytosis that do not present
the classic features for both primary and secondary pathomorphosis. Although usually simple, the diagnosis of dermatophyte infection is sometimes
neglected. Variations in clinical presentation (tinea atypica), mimicking other
skin diseases depend on many factors, partially due to the dermatophyte's
characteristics, and a combination of patient's pathological but often
physiological conditions, such as excessive washing or sun exposure. The
physician's misdiagnosis and eventual prescription of steroids or other
incongruous treatments further induce pathomorphosis (tinea incognito),
longstanding disease and delayed recovery. This review describes the morphology
of some atypical dermatophyte infections, in an attempt to compare and correlate
changes to the normal features of the disease by site of involvement. The risk
factors and predisposing conditions are also analysed to provide a reasoned
interpretation of morphology and therefore evoke the diagnostic suspect in
atypical cases. Periodical training is the clue to improve dermatologist
expertise in what is the first-sight ability to make a diagnosis, perform the
correct assessments and consequent therapy in daily practice. Onychomycosis is a common infection of the nail unit that is usually caused by a
dermatophyte (tinea unguium) and most frequently affects toenails in adults. In
most cases, onychomycosis is associated with limited treatment options that are
effective in achieving complete clearance in many cases. In addition, recurrence
rates are high in the subset of treated patients who have been effectively
cleared, usually with an oral antifungal agent. There has been a conspicuous
absence of medical therapies approved in the United States since the
introduction of topical ciclopirox (8% nail lacquer), with no new effective
agents introduced for more than 10 years. Fortunately, newer agents and
formulations have been under formal development. While patients might prefer a
topical therapy, efficacy with ciclopirox 8% nail lacquer, the only available
agent until the very recent approval of efinaconazole 10% solution, has been
disappointing. The poor therapeutic outcomes achieved with ciclopirox 8% nail
lacquer were not unexpected as the cure rates achieved in the clinical trials
were unimpressive, despite concomitant nail debridement, which was an integral
part of the pivotal trials with ciclopirox 8% nail lacquer. Efinaconazole 10%
solution and tavaborole 5% solution are new topical antifungals specifically
developed for the treatment of dermatophyte onychomycosis. In Phase 3 clinical
trials, both newer agents were applied once daily for 48 weeks without
concomitant nail debridement. Mycologic cure rates with efinaconazole 10%
solution are markedly superior to what was achieved with ciclopirox 8% nail
lacquer. To add, they appear to be nearly comparable to those achieved with oral
itraconazole in pivotal clinical trials. However, it is important to remember
that direct comparisons between different studies are not conclusive, are not
generally considered to be scientifically sound, and may not be entirely
accurate due to differences in study design and other factors. Well-designed and
properly powered head-to-head studies are needed in order to draw definitive
conclusions about efficacy comparisons between therapies, at least based on
academic and regulatory standards. Although tavaborole 5% solution is in an
earlier phase of development for onychomycosis, treatment success rates reported
thus far for both efinaconazole 10% solution and tavaborole 5% solution are
superior to ciclopirox 8% nail lacquer. As a result, a new era of onychomycosis
appears to be upon us that incorporates topical therapy more effectively than in
the past. Not only may these newer topical agents provide viable monotherapy
alternatives to oral therapy for onychomycosis, topical therapy for
onychomycosis that is effective, well tolerated, and easy to use may also find a
role in combination therapy, and/or as continued therapy after initial clearance
to reduce recurrence or re-infection. Internationally adopted children often present diseases contracted in the
country of origin. Skin diseases are common in new arrivals, and diagnosis may
prove challenging for GPs or even dermatologists if they are inexperienced in
the extensive geographic and ethnic diversity of international adoptees. To
analyse the frequency and characteristics of skin diseases in international
adoptees. In total, 142 adoptees were evaluated for a cross-sectional cohort
study. The most frequent diseases observed at arrival were dermatological
conditions. Of the adoptees, 70% presented at least one skin disease, of which
57.5% were infectious; Tinea capitis being the most frequent (n = 42). The
recovery rate of Tinea capitis was 89% (n = 32/36). Ten cases of scabies were
diagnosed. Other diseases included viral skin infection (n = 22), with 16 cases
of Molluscum contagiosum and bacterial infection. Skin diseases are very common
in internationally adopted children. There is a need for close collaboration
between dermatologists and paediatricians to diagnose such infections, as well
as clear guidelines to treat them. |
How are deletion breakpoints defined? | Molecular mapping of deletion breakpoints on chromosome 4 of Drosophila melanogaster. We identified 18 deletion breakpoints at the DNA nucleotide sequence level. Commonly used methods for the detection of CNV breakpoints include long-range PCR and primer walking, their success being limited by the deletion size, GC content and presence of DNA repeats. | Previous studies have shown that approximately 80% of patients with X-linked
ichthyosis have a total deletion of the steroid sulphatase (STS) locus which
lies in Xp22.3-Xpter. We show by Southern analysis that a common core of
sequences are absent in 78.6% of our cases, suggesting that the deletion
breakpoints may be highly clustered. To characterize the region in more detail a
long-range physical map of over 3 megabases (Mb) surrounding the STS locus was
constructed using pulse-field gel electrophoresis. The map enabled the order of
sequences tel-SI19-GMGXY3-[STS,GMGXY19]-GMGX9-[dic56 ,SIII2]-cen and the
localization of the deletion breakpoints to be established. In ten cases the
pulse-field evidence supports the clustering of breakpoints and indicates a
deletion size of 2 Mb in most patients. Five CpG islands have been positioned
around the STS locus and may be associated with other loci in the region
involved in mental retardation and Kallman's syndrome. The map will be
instrumental in an attempt to isolate and characterize the deletion breakpoints
and to access other genes located in the region. A 9.3 kb transposable element of the roo family has been found inserted 3' to
the Sgs-4 glue protein gene of Drosophila. The X chromosome which carries this
insert also carries wDZL, a domit, unstable allele of the white locus caused
by the insertion of the 13 kb wDZL element. Three deletions isolated from the
wDZL strain have molecular breakpoints 3' to Sgs-4 that are associated with the
roo element. Though the deletions eliminate much of the DNA between white and
Sgs-4, none of the distal breakpoints fall at or near the wDZL element. The
results suggest that this copia-like element, which is structurally similar to
an integrated retrovirus, is capable of promoting chromosomal deletions. Thailand deletion of alpha-Thalassemia (thal) 1 involves the zeta2-, phi zeta1-,
alpha2-, alpha1-, and theta1-globin genes. In Southeast Asians and Taiwanese,
this mutation is the second most common long-segment deletion of two
alpha-globin genes, after the Southeast Asian deletion. To define the Thailand
deletion breakpoints, we used polymerase chain reaction (PCR) to amplify the
normal-sequence DNA fragments across the breakpoints. The amplified products
were sequenced directly or after cloning into pGem-3Z or pCR2.1 vectors.
Comparison of the normal and mutant sequences revealed that the 5' breakpoint
lies between nucleotides 1,269 and 1,290 upstream of the initiator codon adenine
of the zeta2-globin gene, and the 3' breakpoint lies between nucleotides 29,387
and 29,408 downstream of it. A total of 30,677 nucleotides were deleted. Both
breakpoints mentioned above lie within the Alu repetitive sequences and an
extensive sequence homology is present around the two breakpoints. These
findings suggest that homologous recombination is the mechanism by which the
deletion occurs. Based on our data, we used three oligonucleotide primers to
amplify the regions across the deletion and its corresponding normal sequence.
The feasibility of PCR diagnosis was confirmed in 20 carriers with this
deletion. Mutations in the HPRT gene cause a spectrum of diseases that ranges from
hyperuricemia alone to hyperuricemia with profound neurological and behavioral
dysfunction. The extreme phenotype is termed Lesch-Nyhan syndrome. In 271 cases
in which the germinal HPRT mutation has been characterized, 218 different
mutations have been found. Of these, 34 (13%) are large- (macro-) deletions of
one exon or greater and four (2%) are partial gene duplications. The deletion
breakpoint junctions have been defined for only three of the 34 macro-deletions.
The molecular basis of two of the four duplications has been defined. We report
here the breakpoint junctions for three new deletion mutations, encompassing
exons 4-8 (20033bp), exons 4 and 5 (13307bp) and exons 5 and 6 (9454bp),
respectively. The deletion breakpoints were defined by a combination of long
polymerase chain reaction (PCR) amplifications, and conventional PCR and DNA
sequencing. All three deletions are the result of non-homologous recombinations.
A fourth mutation, a duplication of exons 2 and 3, is the result of an
Alu-mediated homologous recombination between identical 19bp sequences in
introns 3 and 1. In toto, two of three germinal HPRT duplication mutations
appear to have been caused by Alu-mediated homologous recombination, while only
one of six deletion mutations appears to have resulted from this type of
recombination mechanism. The other five deletion mutations resulted from
non-homologous recombination. With this admittedly limited number of
characterized macro-mutations, Alu-mediated unequal homologous recombinations
account for at least 8% (3 of 38) of the macro-alterations and 1% (3 of 271) of
the total HPRT germinal mutations. BACKGROUND: Segmental duplications flanking the neurofibromatosis type 1 (NF1)
gene locus on 17q11 mediate most gene deletions in NF1 patients. However, the
large size of the gene and the complexity of the locus architecture pose
difficulties in deletion analysis. We report the construction and application of
the first NF1 locus specific microarray, covering 2.24 Mb of 17q11, using a
non-redundant approach for array design. The average resolution of analysis for
the array is approximately 12 kb per measurement point with an increased average
resolution of 6.4 kb for the NF1 gene.
METHODS: We performed a comprehensive array-CGH analysis of 161 NF1 derived
samples and identified heterozygous deletions of various sizes in 39 cases. The
typical deletion was identified in 26 cases, whereas 13 samples showed atypical
deletion profiles.
RESULTS: The size of the atypical deletions, contained within the segment
covered by the array, ranged from 6 kb to 1.6 Mb and their breakpoints could be
accurately determined. Moreover, 10 atypical deletions were observed to share a
common breakpoint either on the proximal or distal end of the deletion. The
deletions identified by array-CGH were independently confirmed using multiplex
ligation-dependent probe amplification. Bioinformatic analysis of the entire
locus identified 33 segmental duplications.
CONCLUSIONS: We show that at least one of these segmental duplications, which
borders the proximal breakpoint located within the NF1 intron 1 in five atypical
deletions, might represent a novel hot spot for deletions. Our array constitutes
a novel and reliable tool offering significantly improved diagnostics for this
common disorder. Copper toxicosis is an autosomal recessive disorder affecting Bedlington
terriers, characterized by elevated liver copper levels and early death of
affected dogs. Genetic linkage mapping studies initially identified linkage
between the disease and the microsatellite marker C04107. Subsequently, the
deletion of exon 2 of the copper metabolism domain containing 1 (COMMD1) gene
(formerly MURR1) was shown to be the major cause of copper toxicosis, although
the deletion breakpoints were not defined. In this investigation, polymerase
chain reaction (PCR)-based techniques and sequencing were used to isolate the
deletion breakpoints, utilizing the newly available dog genome sequence. The
breakpoints were positioned at 65.3091 and 65.3489 Mb of dog chromosome 10, in
intron 1 and intron 2 of COMMD1 respectively, a deletion of 39.7 kb. The two
breakpoints share sequence homology suggesting that homologous recombination may
have been responsible for the deletion. Using this information, a genomic
diagnostic test for the COMMD1 deletion was developed and compared with
microsatellite C04107 genotypes of 40 Bedlington terriers. Results from the 40
samples showed allele 2 of C04107 to be in linkage disequilibrium with the
COMMD1 deletion. Genomic disorders contribute significantly to genetic disease and, as detection
methods improve, greater numbers are being defined. Paralogous low copy repeats
(LCRs) mediate many of the chromosomal rearrangements that underlie these
disorders, predisposing chromosomes to recombination errors. Deletions of
proximal 22q11.2 comprise the most frequently occurring microdeletion syndrome,
DiGeorge/Velocardiofacial syndrome (DGS/VCFS), in which most breakpoints have
been localized to a 3 Mb region containing four large LCRs. Immediately distal
to this region, there are another four related but smaller LCRs that have not
been characterized extensively. We used paralog-specific primers and long-range
PCR to clone, sequence, and examine the distal deletion breakpoints from two
patients with de novo deletions mapping to these distal LCRs. Our results
present definitive evidence of the direct involvement of LCRs in 22q11 deletions
and map both breakpoints to the BCRL module, common to most 22q11 LCRs,
suggesting a potential region for LCR-mediated rearrangement both in the distal
LCRs and in the DGS interval. These are the first reported cases of distal 22q11
deletions in which breakpoints have been characterized at the nucleotide level
within LCRs, confirming that distal 22q11 LCRs can and do mediate rearrangements
leading to genomic disorders. Parkin mutations are responsible for the pathogenesis of autosomal-recessive
juvenile parkinsonism (AR-JP). On initial screening of Japanese patients with
AR-JP, we had found that approximately half of the parkin mutations are
deletions occurring between exons 2 and 5, forming a deletion hot spot. In this
study, we investigated the deletion breakpoints of the parkin mutations in 22
families with AR-JP and examined the possible association between these deletion
events and meiotic recombinations. We identified 18 deletion breakpoints at the
DNA nucleotide sequence level. Almost all these deletions were different,
indicating that the deletion hot spot was generated by recurrent but independent
events. We found no association between the deletions and specific DNA elements.
Recent copy number variation (CNV) data from various ethnic groups showed that
the deletion hot spot is overlapped by a highly polymorphic CNV region,
indicating that the recurrent deletion mutation or CNV is observable worldwide.
By comparing Marshfield and deCODE linkage maps, we found that the parkin
deletion hot spot may be associated with a meiotic recombination hot spot,
although such association was not found on comparison with recent
high-resolution genetic maps generated from the International HapMap project.
Here, we discuss the possible mechanisms for deletion hot spot formation and its
effects on human genomes. Author information:
(1)Department of Health Sciences Research, Center for Individualized Medicine,
Mayo Clinic, 200 1st Street SW, Rochester, Minnesota 55905, USA.
(2)1] Program in Computational Biology and Bioinformatics, Yale University, 266
Whitney Avenue, New Haven, Connecticut 06520, USA [2] Department of Computer
Science, Yale University, New Haven, Connecticut 06520, USA.
(3)Department of Computer Science, Yale University, New Haven, Connecticut
06520, USA.
(4)Bina Technologies, Roche Sequencing, Redwood City, California 94065, USA.
(5)European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg 69117,
Germany.
(6)Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan.
(7)1] Program in Computational Biology and Bioinformatics, Yale University, 266
Whitney Avenue, New Haven, Connecticut 06520, USA [2] Department of Molecular
Biophysics and Biochemistry, School of Medicine, Yale University, New Haven,
Connecticut 06520, USA.
(8)The University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA.
(9)Department of Human Genetics, Wellcome Trust Sanger Institute, Hinxton,
Cambridgeshire CB10 1SA, UK.
(10)1] European Molecular Biology Laboratory, Genome Biology Unit, Heidelberg
69117, Germany [2] European Molecular Biology Laboratory, European
Bioinformatics Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire
CB10 1SD, UK.
(11)The Jackson Laboratory for Genomic Medicine, Farmington, Connecticut 06030,
USA.
(12)1] Program in Computational Biology and Bioinformatics, Yale University, 266
Whitney Avenue, New Haven, Connecticut 06520, USA [2] Department of Molecular
Biophysics and Biochemistry, School of Medicine, Yale University, New Haven,
Connecticut 06520, USA [3] Department of Computer Science, Yale University, New
Haven, Connecticut 06520, USA. Gross chromosomal rearrangements (including translocations, deletions,
insertions and duplications) are a hallmark of cancer genomes and often create
oncogenic fusion genes. An obligate step in the generation of such gross
rearrangements is the formation of DNA double-strand breaks (DSBs). Since the
genomic distribution of rearrangement breakpoints is non-random, intrinsic
cellular factors may predispose certain genomic regions to breakage. Notably,
certain DNA sequences with the potential to fold into secondary structures
[potential non-B DNA structures (PONDS); e.g. triplexes, quadruplexes,
hairpin/cruciforms, Z-DNA and single-stranded looped-out structures with
implications in DNA replication and transcription] can stimulate the formation
of DNA DSBs. Here, we tested the postulate that these DNA sequences might be
found at, or in close proximity to, rearrangement breakpoints. By analyzing the
distribution of PONDS-forming sequences within ±500 bases of 19 947
translocation and 46 365 sequence-characterized deletion breakpoints in cancer
genomes, we find significant association between PONDS-forming repeats and
cancer breakpoints. Specifically, (AT)n, (GAA)n and (GAAA)n constitute the most
frequent repeats at translocation breakpoints, whereas A-tracts occur
preferentially at deletion breakpoints. Translocation breakpoints near
PONDS-forming repeats also recur in different individuals and patient tumor
samples. Hence, PONDS-forming sequences represent an intrinsic risk factor for
genomic rearrangements in cancer genomes. The routine detection of large and medium copy number variants (CNVs) is well
established. Hemizygotic deletions or duplications in the large Duchenne
muscular dystrophy DMD gene responsible for Duchenne and Becker muscular
dystrophies are routinely identified using multiple ligation probe amplification
and array-based comparative genomic hybridization. These methods only map
deleted or duplicated exons, without providing the exact location of
breakpoints. Commonly used methods for the detection of CNV breakpoints include
long-range PCR and primer walking, their success being limited by the deletion
size, GC content and presence of DNA repeats. Here, we present a strategy for
detecting the breakpoints of medium and large CNVs regardless of their size. The
hemizygous deletion of exons 45-50 in the DMD gene and the large autosomal
heterozygous PARK2 deletion were used to demonstrate the workflow that relies on
real-time quantitative PCR to narrow down the deletion region and Sanger
sequencing for breakpoint confirmation. The strategy is fast, reliable and
cost-efficient, making it amenable to widespread use in genetic laboratories. |
How is the nuclear localization of lncRNA mediated? | The lncRNA localization to the nucleus can be mediated by the pentamer sequence AGCCC. | The ubiquitous presence of long noncoding RNAs (lncRNAs) in eukaryotes points to
the importance of understanding how their sequences impact function. As many
lncRNAs regulate nuclear events and thus must localize to nuclei, we analyzed
the sequence requirements for nuclear localization in an intergenic lncRNA named
BORG (BMP2-OP1-responsive gene), which is both spliced and polyadenylated but is
strictly localized in nuclei. Subcellular localization of BORG was not dependent
on the context or level of its expression or decay but rather depended on the
sequence of the mature, spliced transcript. Mutational analyses indicated that
nuclear localization of BORG was mediated through a novel RNA motif consisting
of the pentamer sequence AGCCC with sequence restrictions at positions -8 (T or
A) and -3 (G or C) relative to the first nucleotide of the pentamer. Mutation of
the motif to a scrambled sequence resulted in complete loss of nuclear
localization, while addition of even a single copy of the motif to a
cytoplasmically localized RNA was sufficient to impart nuclear localization.
Further, the presence of this motif in other cellular RNAs showed a direct
correlation with nuclear localization, suggesting that the motif may act as a
general nuclear localization signal for cellular RNAs. |
What is ATAC-seq? | The assay for transposase-accessible chromatin using sequencing (ATAC-seq) was recently established as a method to profile open chromatin, which overcomes the sample size limitations of the alternative methods DNase/MNase-seq. | Assay for transposase-accessible chromatin with high-throughput sequencing
(ATAC-seq) is a useful method to map genome-wide chromatin accessibility and
nucleosome positioning. Genome-wide sequencing is performed utilizing adapter
sequences inserted by a prokaryotic transposase, Tn5, into the accessible
regions of chromatin. Here we describe the use of ATAC-seq in the zebrafish
embryo and thereby the applicability of this approach in whole vertebrate
embryos. The study of epigenetic properties of the human genome, including structural
modifications of DNA and chromatin, has increased tremendously as mounting
evidence has demonstrated how much epigenetics affects human gene expression.
Buenrostro et al. have developed a rapid method, requiring low numbers of living
cells as input, for examining chromatin accessibility across the epigenome,
known as the assay for transposase-accessible chromatin using sequencing
(ATAC-seq). The overall goal of this unit is to provide a thorough ATAC-seq data
analysis plan, as well as describe how primary human blood samples can be
processed for use in ATAC-seq. In addition, a number of quality control
parameters are discussed to ensure the integrity and confidence in the ATAC-seq
data. © 2017 by John Wiley & Sons, Inc. The assay for transposase-accessible chromatin using sequencing (ATAC-seq) was
recently established as a method to profile open chromatin, which overcomes the
sample size limitations of the alternative methods DNase/MNase-seq. To
investigate the role of Piwi in heterochromatin formation around transposable
element loci, we have used ATAC-seq to examine chromatin accessibility at target
transposable elements in a Drosophila cultured cell line, ovarian somatic cells
(OSCs). In this chapter, we describe our method to profile open chromatin
structure in OSCs using ATAC-seq. |
What is the TALE-iD method used for? | TALE-iD is a methylation-based method for the study of native chromatin structure. | Mammalian interphase chromosomes fold into a multitude of loops to fit the
confines of cell nuclei, and looping is tightly linked to regulated function.
Chromosome conformation capture (3C) technology has significantly advanced our
understanding of this structure-to-function relationship. However, all 3C-based
methods rely on chemical cross-linking to stabilize spatial interactions. This
step remains a "black box" as regards the biases it may introduce, and some
discrepancies between microscopy and 3C studies have now been reported. To
address these concerns, we developed "i3C", a novel approach for capturing
spatial interactions without a need for cross-linking. We apply i3C to intact
nuclei of living cells and exploit native forces that stabilize chromatin
folding. Using different cell types and loci, computational modeling, and a
methylation-based orthogonal validation method, "TALE-iD", we show that native
interactions resemble cross-linked ones, but display improved signal-to-noise
ratios and are more focal on regulatory elements and CTCF sites, while strictly
abiding to topologically associating domain restrictions. |
What is Paget's Disease? | Paget's disease of bone (PDB) is a noninflammatory, metabolic, skeletal disorder characterized by localized excessive osteoclastic bone resorption that is followed by compensatory increased osteoblastic activity leading to unstructured, fibroblastic, and biomechanically unstable bone. | Paget's disease of bone is characterized by the progressive and extensive
replacement, in one or several bones, of normal bone tissue by a bone tissue of
rough and irregular structure, the excessive and disorderly renewal of which
gradually produces hyperdensity and hypertrophy of the bones involved. The
condition results from the action of abnormal and overactive osteoclasts
containing virus-like intranuclear and intracytoplasmic inclusions. The disease
profoundly alters the physiology of bones in the region affected. The
viral-looking inclusions that enter the osteoclasts seem to induce a loss of
control of bone renewal and remodelling, as shown by histology and radiology.
The resorption-formation mechanism persists but it is unbalanced, facilitating
bone resorption during two to five years, then bone formation. In that way,
subjects with Paget's disease, who have reached the age of physiological
osteopenia, show an often important increase in bone density and mass. Paget's
disease of bone is a disease grafted on the skeleton: it is partly dependent on
the skeletal status of the host. The activity of Paget's disease is evaluated by
measuring the ratio of plasma alkaline phosphatase levels to the volumes of
normal and pagetic bones; the author suggests a mathematical formula for
calculating this ratio. Paget disease of the vulva can be mimicked by several disease entities
histopathologically, but most of these entities can be clinically distinguished
from vulvar Paget disease. However, vulvar Paget disease is in itself a
heterogeneous group of epithelial neoplasms that can be similar both clinically
and histopathologically. The subtypes of vulvar Paget disease include primary
Paget disease arising from a pluripotent stem cell within the epithelium of the
vulva, and secondary Paget disease of the vulva. Secondary vulvar Paget disease
results from spread of an internal maligcy, most commonly from an anorectal
adenocarcinoma or urothelial carcinoma of the bladder or urethra, to the vulvar
epithelium. We have recently proposed that these lesions be classified as
primary (of cutaneous origin) or secondary (of extracutaneous origin). These
subtypes can present similarly as eczematoid skin lesions and may appear similar
on routine hematoxylin and eosin-stained slides. Immunohistochemical studies can
help differentiate between them. Our current study includes 17 patients with a
pathologic diagnosis of vulvar Paget disease. We performed a panel of
immunohistochemical stains, including cytokeratin (CK) 7 and 20,
carcinoembryonic antigen (CEA), gross cystic disease fluid protein-15
(GCDFP-15), and uroplakin-III (UP-III). Of these 17 patients, 14 (80%) had
primary intraepithelial cutaneous Paget disease, 13 without invasion and 1 with
associated invasion. Three patients had urothelial carcinoma with spread to the
vulva, manifesting as secondary vulvar Paget disease. Immunohistochemically,
primary vulvar Paget disease is immunoreactive for CK 7 and GCDFP-15, but
uncommonly for CK 20. Vulvar Paget disease secondary to anorectal carcinoma
demonstrates CK 20 immunoreactivity but is usually nonreactive for CK 7 and
consistently nonimmunoreactive for GCDFP-15. Vulvar Paget disease secondary to
urothelial carcinoma is immunoreactive for CK 7 and CK 20 but nonimmunoreactive
for GCDFP-15. In addition, we propose the use of a new, commercially available
antibody, UP-III, which is specific for urothelium and, in our experience, is
immunoreactive in secondary vulvar Paget disease of urothelial origin. The
distinction between these 3 types of Paget and Paget-like lesions is essential
in that the specific diagnosis has a significant influence on current treatment.
The difference in surgical approach to the subtypes of vulvar Paget disease
justifies classifying them into distinct lesions, which may be aided by the use
of immunohistochemistry, including UP-III. Paget's disease of bone is a chronic focal skeletal disorder that affects up to
2-3% of the population over the age of 60 years. Paget's disease is primarily a
disease of the osteoclast. The pathologic abnormality in patients with Paget's
disease involves increased bone resorption by the osteoclasts, followed by
abundant new bone formation that is of poor quality. Genetic linkage analysis
indicated that 40% of patients with Paget's disease have an affected first
degree relative and 1% of patients develop osteosarcoma. Paget's disease is an
autosomal domit trait with genetic heterogeneity. Recurrent mutations in the
ubiquitin-associated (UBA) domain of sequestosome 1 (SQSTM1/p62) are identified
in patients with Paget's disease. Osteoclasts and osteoclast precursors from
patients with Paget's disease contain paramyxoviral transcripts and appear
hyperresponsive to 1,25-(OH)2D3 and RANK ligand (RANKL). It has been suggested
that the enhanced sensitivity of osteoclast precursors for 1,25-(OH)2D3 in
Paget's disease results from increased expression of coactivators of vitamin D
receptor (VDR). However, a cause and effect relationship for the paramyxoviral
infection and SQSTM1/p62 gene mutations associated with this disease and
osteoclast abnormalities are unclear. Therefore, the etiology of Paget's disease
remains uncertain. Mammary Paget's disease and extramammary Paget's disease are rare
intraepithelial neoplasms. Mammary Paget's disease is almost exclusively
associated with underlying invasive breast carcinoma or high-grade ductal
carcinoma in situ (DCIS G3). Extramammary Paget's disease arises in areas rich
in apocrine glands and is suspected to have apocrine gland origin. The aim of
the study was to investigate the presence of estrogen receptor (ER),
progesterone receptor (PR), androgen receptor (AR) and Her2/neu in a large
number of cases. We investigated 58 cases of mammary and 23 cases of
extramammary Paget's disease. Formalin-fixed and paraffin-embedded tissues were
analyzed using antibodies against AR, PR, ER and Her2/neu according to
standardized procedures. In mammary Paget's disease, positive immunoreactions
for Her2/neu, AR and ER were observed in 56 of 58 (97%), 51 of 58 (88%), and
respectively in six of 58 (10%) cases. All cases of mammary Paget's disease were
negative for PR and showed a coexpression of Her2/neu and AR in 51 out of 58
cases (88%). In extramammary Paget's disease, positive immunoreactions for AR,
Her2/neu and ER were observed in 18 of 23 (78%), 12 of 23 (52%), and
respectively in 1 of 23 (4%) cases. All cases of extramammary Paget's disease
were negative for PR and showed a coexpression of AR and Her2/neu in 12 out of
23 cases (52%). In contrast to ER and PR, AR and Her2/neu are commonly expressed
in mammary and extramammary Paget's disease. The knowledge about frequent
expression of AR in Paget's disease could lead to the development of a new
adjuvant therapy, particularly in patients with recurrent disease. Paget's disease of bone is a chronic focal skeletal disorder characterized by
increased bone resorption by the osteoclasts. Paramyxoviral gene products have
been detected in pagetic osteoclasts. Paget's disease is an autosomal domit
trait with genetic heterogeneity. Several mutations in the ubiquitin-associated
(UBA) domain of sequestosome 1 (SQSTM1/p62) have been identified in patients
with Paget's disease. Similarly, mutations in the valosin-containing protein
(VCP) gene have been shown to cause inclusion body myopathy associated with
Paget's disease of bone and frontotemporal dementia. In addition, gene
polymorphisms and enhanced levels of cytokine/growth factors associated with
Paget's disease have been identified. However, the etiologic factors in Paget's
disease remain elusive. A cause and effect relationship for the paramyxoviral
infection and SQSTM1/ p62 gene mutations responsible for pagetic osteoclast
development and disease severity are unclear. This article will highlight the
etiologic factors involved in the pathogenesis of Paget's disease. Paget's disease is an intra-epidermal adenocarcinoma seen over the nipple/areola
(mammary Paget's disease) or in extramammary body zones, such as the anogenital
and perineal skin and the axilla. Mammary and extramammary Paget's disease share
many common clinicopathological features but also show several differences,
namely, with regard to pathogenesis and association with underlying
maligcies. Indeed, mammary Paget's disease is as a rule associated with an
underlying breast carcinoma whereas association of extramammary Paget's disease
with underlying (skin or visceral) maligcies occurs much less frequently. We
review here the main clinicopathological and therapeutic features of mammary and
extramammary Paget's disease. Pagetoid spread of primary esophageal melanomas and several cases of pagetoid
esophageal squamous cell carcinoma are known. However, true esophageal Paget
disease (intraepithelial growth of neoplastic cells with glandular
differentiation) has only rarely been reported. We encountered 3 endoscopic
biopsy specimens containing Paget cells in squamous epithelium associated with
adenocarcinomas in Barrett esophagus (BE) and in the esophagogastric junction.
To determine the prevalence of Paget cells in the esophagus, we studied 81
endoscopic mucosal resections and 27 esophagectomies from patients with invasive
or intramucosal adenocarcinoma, and compared the findings to a control group of
47 endoscopic mucosal resections and 25 esophagectomies from patients with
high-grade dysplasia in BE. Paget cells were present in squamous epithelium
overlying 5 (4.9%) of 108 adenocarcinomas but in none (0%) of 72 BE with
high-grade dysplasia (P=0.16). A computerized search for primary Paget disease
using the terms "Paget's and esophagus" or "pagetoid and esophagus" from 1994 to
2007 did not yield any additional cases. Among the 8 patients with Paget cells
(including the 2 index biopsies) there were no differences in either sex
distribution (7M:1F) or age (mean 62.4 y) as compared with 103 adenocarcinomas
without Paget cells (93M:10F, P=0.58; mean age 69.2 y, P=0.78). Morphologically,
all adenocarcinomas with Paget cells contained at least a component of diffuse,
poorly differentiated adenocarcinoma, and 1 was a signet ring cell carcinoma.
Paget cells involved only squamous epithelium directly above the poorly
differentiated tumor foci. Histochemistry for periodic acid-Schiff with diastase
(PAS-D) and mucicarmine, and immunohistochemistry for CK7, CK20, p53, and
E-cadherin, were performed on 7 Paget cases with the following results: PAS-D+
(7 of 7, 100%), mucicarmine+ (6 of 7, 86%), CK7+ (7 of 7, 100%), CK20+ (5 of 7,
71%), p53 overexpression (3 of 7, 43%), and E-cadherin loss (complete loss in 1
and faint expression in 3, 57%). Overall, PAS-D was the most efficacious stain
for highlighting Paget cells. A control group of 19 adenocarcinomas without
Paget cells were also stained for E-cadherin; only 1 showed faint expression
(5%) and none showed complete loss (P=0.01). These results demonstrate a low but
significant prevalence (4.9%) of Paget cells in esophageal and esophagogastric
junction adenocarcinomas. Unlike previously described cases of mammary, vulvar,
and perianal Paget disease, esophageal Paget cells are almost universally
associated with underlying adenocarcinoma and not with high grade dysplasia ("in
situ" disease) or primary Paget disease. A commonality among cases with Paget
cells is the presence of focal or diffuse, poorly differentiated adenocarcinoma
with discohesive cells. E-cadherin alterations seem to play a less significant
role. Paget's disease of bone is a focal disorder of aging bone. The classic
late-onset Paget's disease is often caused by a P392L mutation in the gene
SQSTM1, which disturbs signaling pathways in osteoclasts on cell activation.
This prevalent mutation is neither necessary nor sufficient to cause Paget's
disease. Its identification, along with the elucidation of other mutations
underlying early-onset Paget's and Paget's disease seen in association with
inclusion body myopathy and frontotemporal dementia, have redefined our
understanding of genetic disorders of bone remodeling by emphasizing the
importance of environmental determits in their pathophysiology. Paget's disease of the breast is a disorder of the nipple-areola complex that,
while rare, is often associated with an underlying carcinoma. It is
characterized by eczematoid changes of the nipple. Two theories have been
proposed to explain the pathogenesis of Paget's disease. The Epidermotropic,
which is the most accepted theory, suggests that Paget's cells originate from
ductal cancer cells that had migrated from the underlying breast parenchyma. It
is supported by the predomice of breast cancer markers found in Paget's
disease. This article provides an overview of Paget's disease of the breast with
special attention to immunohistochemistry and raises the question of new
therapeutic approaches. Der Morbus Paget ist eine nichtentzündliche metabolische Knochenerkrankung, die
durch eine lokale, übermäßige Knochenresorption mit kompensatorischer Steigerung
der Osteoblastenaktivität gekennzeichnet ist. In Folge kommt es zu einem
veränderten, fibrösen und biomechanisch instabilen Knochen sowie zu
Deformierungen und Verdickungen des Knochens mit einer gestörten und
desorganisierten Struktur. In diesem Beitrag geben wir eine Übersicht über die
Epidemiologie, Ätiologie, Pathologie, Makrostruktur, Histologie und die
quantitative Histomorphometrie des Morbus Paget. Das Auftreten von
Riesenosteoklasten und die schlechte Abgrenzbarkeit von kortikalem und
trabekulärem Knochen sind wichtige histologische Kennzeichen der Erkrankung.
Darüber hinaus ist der Knochen bei Morbus Paget auch durch eine Hypertrophie und
Veränderungen der Trabekelstruktur gekennzeichnet. Paget's disease of the bone is a chronic osteopathy that leads to structural
weakness, hypervascularity, and bone deformities. Rapid bone turnover in
patients with Paget's disease may affect outcomes following total hip
arthroplasty (THA). Most literature on THA in the setting of Paget's disease is
limited to isolated case reports or case series documenting a single institution
experience. By completing a comprehensive analysis of the available cases, this
study aims to investigate the outcomes and complications of THA in patients with
Paget's disease. Paget's disease of bone (PDB) is the second most common metabolic bone disorder,
after osteoporosis. It is characterised by focal areas of increased and
disorganised bone turnover, coupled with increased bone formation. This disease
usually appears in the late stages of life, being slightly more frequent in men
than in women. It has been reported worldwide, but primarily affects individuals
of British descent. Majority of PDB patients are asymptomatic, but clinical
manifestations include pain, bone deformity and complications, like pathological
fractures and deafness. The causes of the disease are poorly understood and it
is considered as a complex trait, combining genetic predisposition with
environmental factors. Linkage analysis identified SQSTM1, at chromosome 5q35,
as directly related to the disease. A number of mutations in this gene have been
reported, pP392L being the most common variant among different populations. Most
of these variants affect the ubiquitin-associated (UBA) domain of the protein,
which is involved in autophagy processes. Genome-wide association studies
enlarged the number of loci associated with PDB, and further fine-mapping
studies, combined with functional analysis, identified OPTN and RIN3 as causal
genes for Paget's disease. A combination of risk alleles identified by
genome-wide association studies led to the development of a score to predict
disease severity, which could improve the management of the disease. Further
studies need to be conducted to elucidate other important aspects of the trait,
such as its focal nature and the epidemiological changes found in some
populations. In this review, we summarize the clinical characteristics of the
disease and the latest genetic advances to identify susceptibility genes. We
also list current available treatments and prospective options. Adult PD of bone is the second commonest metabolic bone condition after
osteoporosis. The condition is characterized by increased bone cell activity,
with bone-resorbing osteoclasts often larger and containing more nuclei than
normal, and osteoblasts producing increased amounts of disorganized bone. This
leads to expanded bone of poor quality possessing both sclerotic and lytic
areas. PD of bone has a strong genetic element, with a family history being
noted in 10-20% of cases. A number of genetic defects have been found to be
associated with the condition. The most common disease-associated variants
identified affect the SQSTM1 gene, providing insights into disease aetiology,
with the clinical value of knowledge of SQSTM1 mutation status currently under
active investigation. The diagnosis may be suggested by an isolated raised total
ALP without other identifiable causes. This can be confirmed on plain X-rays and
the extent determined by isotope bone scan. The mainstays of treatment are the
bisphosphonates, especially i.v. zoledronate, which results in long-term
suppression of bone turnover. ALP is the usual means of monitoring the
condition, although more specific bone turnover markers can be helpful,
especially in coincident liver disease. Patients should be followed up to
monitor for biochemical relapse or development of complications, which may
require medical or surgical intervention. |
What is the function of penicillinase, also known as beta lactamase? | Beta-lactamases are a family of serine enzymes that hydrolyse beta-lactam antibiotics following an acylation-deacylation mechanism. | The therapeutic problems posed by class D beta-lactamases, a family of serine
enzymes that hydrolyse beta-lactam antibiotics following an
acylation-deacylation mechanism, are increased by the very low level of
sensitivity of these enzymes to beta-lactamase inhibitors. To gain structural
and mechanistic insights to aid the design of new inhibitors, we have determined
the crystal structure of OXA-13 from Pseudomonas aeruginosa in the apo form and
in complex with the carbapenem meropenem. The native form consisted of a dimer
displaying an overall organisation similar to that found in the closely related
enzyme OXA-10. In the acyl-enzyme complex, the positioning of the antibiotic
appeared to be ensured mainly by (i) the covalent acyl bond and (ii) a strong
salt-bridge involving the carboxylate moiety of the drug. Comparison of the
structures of OXA-13 in the apo form and in complex with meropenem revealed an
unsuspected flexibility in the region of the essential serine 115 residue, with
possible consequences for the catalytic properties of the enzyme. In the apo
form, the Ser115 side-chain is oriented outside the active site, whereas the
general base Lys70 adopts a conformation that seems to be incompatible with the
activation of the catalytic water molecule required for the deacylation step. In
the OXA-13:meropenem complex, a 3.5 A movement of the backbone of the 114-116
loop towards the side-chain of Lys70 was observed, which seems to be driven by a
displacement of the neighbouring 91-104 loop and which results in the
repositioning of the side-chain hydroxyl group of Ser115 toward the catalytic
centre. Concomitantly, the side-chain of Lys70 is forced to curve in the
direction of the deacylating water molecule, which is then strongly bound and
activated by this residue. However, a distance of ca 5 A separates the catalytic
water molecule from the acyl carbonyl group of meropenem, a structural feature
that accounts for the inhibition of OXA-13 by this drug. Finally, the low level
of penicillinase activity revealed by the kinetic analysis of OXA-13 could be
related to the specific presence in position 73 of a serine residue located
close to the general base Lys70, which results in a decrease of the number of
hydrogen-bonding interactions stabilising the catalytic water molecule. There is a constant need to identify novel inhibitors to combat
β-lactamase-mediated antibiotic resistance. In this study, we identify three
penicillinase-binding peptides, P1 (DHIHRSYRGEFD), P2 (NIYTTPWGSNWS), and P3
(SHSLPASADLRR), using a phage display library. Surface plasmon resoce (SPR)
is utilized for quantitative determination and comparison of the binding
specificity of selected peptides to penicillinase. An SPR biosensor
functionalized with P3-GGGC (SHSLPASADLRRGGGC) is developed for detection of
penicillinase with excellent sensitivity (15.8 RU nM(-1)) and binding affinity
(KD = 0.56 nM). To determine if peptides can be good inhibitors for
penicillinase, these peptides are mixed with penicillinase and their inhibition
efficiency is determined by measuring the hydrolysis of substrate penicillin G
using UV-vis spectrophotometry. Peptide P2 (NIYTTPWGSNWS) is found to be a
promising penicillinase inhibitor with a Ki of 9.22 μM and a Ki' of 33.12 μM,
suggesting that the inhibition mechanism is a mixed pattern. This peptide
inhibitor (P2) can be used as a lead compound to identify more potent small
molecule inhibitors for penicillinase. This study offers a potential approach to
both detection of β-lactamases and development of novel inhibitors of
β-lactamases. |
The common house cat, Felis silvestris catus and the domestic dog, Canis familiaris both belong to what taxonomic order? | Domestic dogs and cats can be interpreted in terms of their descent from members of the order Carnivora. | |
What is caused by the ectopic expression of CTCF? | ectopic expression of CTCF in K562 cells led to growth retardation and promotion of differentiation into the erythroid lineage; | The cellular protooncogene MYC encodes a nuclear transcription factor that is
involved in regulating important cellular functions, including cell cycle
progression, differentiation, and apoptosis. Dysregulated MYC expression appears
critical to the development of various types of maligcies, and thus factors
involved in regulating MYC expression may also play a key role in the
pathogenesis of certain cancers. We have cloned one such MYC regulatory factor,
termed CTCF, which is a highly evolutionarily conserved-11-zinc finger
transcriptional factor possessing multiple DNA sequence specificity. CTCF binds
to a number of important regulatory regions within the 5' noncoding sequence of
the human MYC oncogene, and it can regulate its transcription in several
experimental systems. CTCF mRNA is expressed in cells of multiple different
lineages. Enforced ectopic expression of CTCF inhibits cell growth in culture.
Southern blot analyses and fluorescence in situ hybridization (FISH) with normal
human metaphase chromosomes showed that the human CTCF is a single-copy gene
situated at chromosome locus 16q22. Cytogenetic studies have pointed out that
chromosome abnormalities (deletions) at this locus frequently occur in many
different human maligcies, suggesting the presence of one or more tumor
suppressor genes in the region. To narrow down their localization, several loss
of heterozygosity (LOH) studies of chromosome arm 16q in sporadic breast and
prostate cancers have been carried out to define the most recurrent and smallest
region(s) of overlap (SRO) for commonly deleted chromosome arm 16q material. For
CTCF to be considered as a candidate tumor suppressor gene associated with
tumorigenesis, it should localize within one of the SROs at 16q. Fine-mapping of
CTCF has enabled us to assign the CTCF gene to about a 2 centiMorgan (cM)
interval of 16q22.1 between the somatic cell hybrid breakpoints CY130(D) and
CY4, which is between markers D16S186 (16AC16-101) and D16S496 (AFM214zg5). This
relatively small region, containing the CTCF gene, overlaps the most frequently
observed SROs for common chromosomal deletions found in sporadic breast and
prostate tumors. In one of four analyzed paired DNA samples from primary breast
cancer patients, we have detected a tumor-specific rearrangement of CTCF exons
encoding the 11-zinc-finger domain. Therefore, taken together with other CTCF
properties, localization of CTCF to a narrow cancer-associated chromosome region
suggests that CTCF is a novel candidate tumor suppressor gene at 16q22.1. CTCF is a highly conserved, ubiquitously expressed DNA-binding protein that has
widespread capabilities in gene regulation. CTCF plays important roles in cell
growth regulatory processes and epigenetic functions. Ectopic expression of CTCF
results in severe cell growth inhibition at multiple points within the cell
cycle, indicating that CTCF levels must be stringently monitored. We have
investigated the subcellular localization of CTCF in detail. Interestingly, we
observe that CTCF shows a dynamic cell cycle-dependent distribution.
Immunofluorescent staining reveals that in interphase CTCF is a nuclear protein,
which is mainly excluded from the nucleolus. Strikingly, CTCF is associated with
the centrosome during mitosis, especially from metaphase to anaphase. At
telophase, CTCF dissociates from the centrosome and localizes to the midbody and
the reformed nuclei. The association of CTCF with centrosomes and the midbody is
further confirmed by biochemical fractionation. Moreover, subcellular fractions
of CTCF show cell cycle and organelle-specific posttranslational modifications,
suggesting different roles for CTCF at different stages of the cell cycle. CTCF is a transcription factor and a candidate tumor suppressor that contains a
DNA-binding domain composed of 11 zinc fingers. We reported previously that CTCF
is differentially regulated during differentiation of human myeloid leukemia
cells. In this study we aimed to investigate the role of CTCF in myeloid cell
differentiation. A human cell line, K562, that can be chemically induced to
differentiate into various hematopoietic lineages was chosen as a model system
for this study. Several K562 cell lines with constitutive and conditional
expression of CTCF have been generated. By using these model systems we
demonstrated that: (i) ectopic expression of CTCF in K562 cells led to growth
retardation and promotion of differentiation into the erythroid lineage; (ii)
CTCF knock-down significantly inhibited differentiation of K562 cells into
erythroid lineage; (iii) differentiation of K562 into the megakaryocytic lineage
was not significantly affected; and (iv) down-regulation of MYC has been
identified as one of the mechanisms by which CTCF promotes erythroid
differentiation. Taken together our results demonstrate that CTCF is involved in
the control of myeloid cell growth and differentiation. Author information:
(1)Molecular Pathology Section, Laboratory of Immunogenetics, National Institute
of Allergy and Infectious Diseases, National Institutes of Health, Rockville,
MD, 20852, USA.
(2)Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA, 92093,
USA.
(3)Department of Cellular and Molecular Medicine, Institute of Genomic Medicine,
Moores Cancer Center, San Diego School of Medicine, University of California,
San Diego, La Jolla, CA, 92093, USA.
(4)Stem Cell Project, Tokyo Metropolitan Institute of Medical Science,
Kamikitazawa, Setagaya-ku, Tokyo, Japan.
(5)Bioinformatics and Computational Biosciences Branch, Office of Cyber
Infrastructure and Computational Biology, National Institute of Allergy and
Infectious Diseases, National Institutes of Health, Bethesda, MD, 20892, USA.
(6)Guangzhou Institutes of Biomedicine and Health, Molecular Epigenetics
Laboratory, 190 Kai Yuan Avenue, Science Park, Guangzhou, 510530, China.
(7)Gene and Stem Cell Therapy Program, Centenary Institute, Camperdown, NSW,
2050, Australia.
(8)Sydney Medical School, University of Sydney, Sydney, NSW, 2006, Australia.
(9)Cell and Molecular Therapies, Royal Prince Alfred Hospital, Camperdown, NSW,
2050, Australia.
(10)Ludwig Institute for Cancer Research, 9500 Gilman Drive, La Jolla, CA,
92093, USA. [email protected].
(11)Department of Cellular and Molecular Medicine, Institute of Genomic
Medicine, Moores Cancer Center, San Diego School of Medicine, University of
California, San Diego, La Jolla, CA, 92093, USA. [email protected].
(12)Molecular Pathology Section, Laboratory of Immunogenetics, National
Institute of Allergy and Infectious Diseases, National Institutes of Health,
Rockville, MD, 20852, USA. [email protected]. CCCTC-binding factor (CTCF) is a DNA-binding protein that interacts with a large
number of highly divergent target sequences throughout the genome. It is
implicated in a variety of functions, including chromatin organization and
transcriptional control. The functional role of CTCF in tumour pathogenesis
remains elusive. We showed that CTCF is frequently upregulated in a subset of
primary hepatocellular carcinomas (HCCs) as compared with non-tumoural liver.
Overexpression of CTCF was associated with shorter disease-free survival of
patients. Short hairpin RNA (shRNA)-mediated suppression of CTCF inhibited cell
proliferation, motility and invasiveness in HCC cell lines; these effects were
correlated with prominent reductions in the expression of telomerase reverse
transcriptase (TERT), the shelterin complex member telomerase repeat-binding
factor 1, and forkhead box protein M1 (FOXM1). In contrast, upregulation of CTCF
was positively correlated with FOXM1 and TERT expression in clinical HCC
biopsies. Depletion of CTCF resulted in reduced motility and invasiveness in HCC
cells that could be reversed by ectopic expression of FOXM1, suggesting that
FOXM1 is one of the important downstream effectors of CTCF in HCC. Reporter gene
analysis suggested that depletion of CTCF is associated with reduced FOXM1 and
TERT promoter activity. Chromatin immunoprecipitation (ChIP)-polymerase chain
reaction (PCR) analysis further revealed occupancy of the FOXM1 promoter by CTCF
in vivo. Importantly, depletion of CTCF by shRNA significantly inhibited tumour
progression and metastasis in HCC mouse models. Our work uncovered a novel
functional role of CTCF in HCC pathogenesis, which suggests that targeting CTCF
could be further explored as a potential therapeutic strategy for HCC. © 2017
The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on
behalf of Pathological Society of Great Britain and Ireland. |
What is the dardarin protein? | Mutations in the leucine-rich repeat kinase 2 gene (LRRK2 or Dardarin) are considered to be a common cause of autosomal dominant and sporadic Parkinson´s disease, | Missense mutations in leucine-rich repeat kinase 2 (LRRK2)/Dardarin gene, the
product of which encodes a kinase with multiple domains, are known to cause
autosomal domit late onset Parkinson's disease (PD). In the current study, we
report that the gene product LRRK2 directly phosphorylates the forkhead box
transcription factor FoxO1 and enhances its transcriptional activity. This
pathway was found to be conserved in Drosophila, as the Drosophila LRRK2 homolog
(dLRRK) enhanced the neuronal toxicity of FoxO. Importantly, FoxO mutants that
were resistant to LRRK2/dLRRK-induced phosphorylation suppressed this
neurotoxicity. Moreover, we have determined that FoxO targets hid and bim in
Drosophila and human, respectively, are responsible for the LRRK2/dLRRK-mediated
cell death. These data suggest that the cell death molecules regulated by FoxO
are key factors during the neurodegeneration in LRRK2-linked PD. BACKGROUND: Pathogenic mutations in leucine-rich repeat kinase 2 (LRRK2; PARK8)
encoding dardarin, implicated in patients with autosomal domit and sporadic
Parkinson's disease (PD) among different ethnic groups (Ashkenazi Jews, North
African Arabs, Basques) might be of some help in diagnostic screening and
genetic counseling.
AIM OF THE STUDY: We investigated the seven common mutations spanning exons 31,
35, and 41 reported in the LRRK2 gene among Eastern Indian patients with PD.
METHODS: Mutations R1441G, R1441C, R1441H, G2019S, Y1699C, I2020T, and I2012T
were screened in 320 individuals (PD, 150 and controls, 170) by direct
sequencing.
RESULTS: We did not observe any of these abovementioned mutations in our studied
individuals.
CONCLUSION: We conclude that these mutations are rare causes of PD in the
Eastern Indian population and, therefore, of little help for genetic counseling
and diagnostic purposes. Mutations in LRRK2 (leucine-rich repeat kinase 2) (also known as PARK8 or
dardarin) are responsible for the autosomal-domit form of PD (Parkinson's
disease). LRRK2 mutations were found in approximately 3-5% of familial and 1-3%
of sporadic PD cases with the highest prevalence (up to 40%) in North Africans
and Ashkenazi Jews. To date, mutations in LRRK2 are a major genetic risk factor
for familial and sporadic PD. Despite the fact that 8 years have passed from the
establishment of the first link between PD and dardarin in 2004, the
pathophysiological role of LRRK2 in PD onset and progression is far from clearly
defined. Also the generation of different LRRK2 transgenic or knockout animals
has not provided new hints on the function of LRRK2 in the brain. The present
paper reviews recent evidence regarding a potential role of LRRK2 in the
regulation of membrane trafficking from vesicle generation to the movement along
cytoskeleton and finally to vesicle fusion with cell membrane. OBJECTIVES: The worldwide spread of Parkinson's disease (PD) calls for sensitive
and specific measures enabling its early (or, ideally, preclinical) detection.
Here, we use language measures revealing deficits in PD to explore whether
similar disturbances are present in asymptomatic individuals at risk for the
disease.
METHODS: We administered executive, semantic, verb-production, and syntactic
tasks to sporadic PD patients, genetic PD patients with PARK2 (parkin) or LRRK2
(dardarin) mutation, asymptomatic first-degree relatives of the latter with
similar mutations, and socio-demographically matched controls. Moreover, to
detect sui generis language disturbances, we ran analysis of covariance tests
using executive functions as covariate.
RESULTS: The two clinical groups showed impairments in all measures, most of
which survived covariation with executive functions. However, the key finding
concerned asymptomatic mutation carriers. While these subjects showed intact
executive, semantic, and action-verb production skills, they evinced deficits in
a syntactic test with minimal working memory load.
CONCLUSIONS: We propose that this sui generis disturbance may constitute a
prodromal sign anticipating eventual development of PD. Moreover, our results
suggest that mutations on specific genes (PARK2 and LRRK2) compromising basal
ganglia functioning may be subtly related to language-processing mechanisms.
(JINS, 2017, 23, 150-158). |
In which syndrome is the RPS19 gene most frequently mutated? | Ribosomal protein S19 (RPS19), currently the only gene associated with DBA, is mutated in 25% of DBA patients, but its role in erythropoiesis is unknown. | We report on maternal first cousins with bilateral microtia, micrognathia, cleft
palate and hematologic findings of Diamond-Blackfan anemia (DBA). The similarity
of findings shared between our cases and a female reported by Hasan and Inoue
[1993] suggests that this is a distinctive syndrome, rather than a chance
association. DBA is a heterogeneous disorder, caused in about 25% of cases by
heterozygous mutations in the RPS19 gene (DBA1). Mutation analysis in our cases
did not show an RPS19 mutation, and 2 alleles were present in each. Segregation
analysis for DBA1 on chromosome 19 and DBA2 on 8p23 was not consistent with
linkage. We conclude that this syndrome of microtia, cleft palate and DBA is not
allelic to known DBA loci. Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome
characterized by a specific deficiency in erythroid progenitors. Forty percent
of the patients are blood transfusion-dependent. Recent reports show that the
ribosomal protein S19 (RPS19) gene is mutated in 25% of all patients with DBA.
We constructed oncoretroviral vectors containing the RPS19 gene to develop gene
therapy for RPS19-deficient DBA. These vectors were used to introduce the RPS19
gene into CD34(+) bone marrow (BM) cells from 4 patients with DBA with RPS19
gene mutations. Overexpression of the RPS19 transgene increased the number of
erythroid colonies by almost 3-fold. High expression levels of the RPS19
transgene improved erythroid colony-forming ability substantially whereas low
expression levels had no effect. Overexpression of RPS19 had no detrimental
effect on granulocyte-macrophage colony formation. Therefore, these findings
suggest that gene therapy for RPS19-deficient patients with DBA using viral
vectors that express the RPS19 gene is feasible. Ribosomal protein S19 (RPS19) is frequently mutated in Diamond-Blackfan anemia
(DBA), a rare congenital hypoplastic anemia. Recent studies have shown that
RPS19 expression decreases during terminal erythroid differentiation. Currently
no information is available on the subcellular localization of normal RPS19 and
the potential effects of various RPS19 mutations on cellular localization. In
the present study, using wild-type and mutant RPS19 cDNA, we explored the
subcellular distribution of normal and mutant proteins in a fibroblast cell line
(Cos-7 cells). RPS19 was detected primarily in the nucleus, and more
specifically in the nucleoli, where RPS19 colocalized with the nucleolar protein
nucleolin. Using various N-terminal and C-terminal deletion constructs, we
identified 2 nucleolar localization signals (NoSs) in RPS19: the first
comprising amino acids Met1 to Arg16 in the NH2-terminus and the second
comprising Gly120 to Asn142 in the COOH-terminus. Importantly, 2 mutations
identified in DBA patients, Val15Phe and Gly127Gln, each of which localized to 1
of the 2 NoS, failed to localize RPS19 to the nucleolus. In addition to their
mislocalization, there was a dramatic decrease in the expression of the 2 mutant
proteins compared to the wild type. This decrease in protein expression was
specific for the mutant RPS19, since expression of other proteins was normal.
The present findings enable us to document the nucleolar localization signals in
RPS19 and help define the phenotypic consequences of some mutations in RPS19 in
DBA. Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome
characterized by a specific deficiency in erythroid progenitors. Since some
patients with DBA develop a reduction in thrombocytes and granulocytes with age,
we asked whether multipotent hematopoietic progenitors from DBA patients had
normal proliferative capacity in liquid expansion cultures. CD34(+) cells
derived from DBA patients showed deficient proliferation in liquid culture
containing IL-3, IL-6, and SCF. Single CD34(+) CD38(-) cells from DBA patients
exhibited deficient proliferation recruitment in a limiting dilution assay
containing IL-3, IL-6, SCF, Tpo, FL, and G-CSF or containing IL-3, IL-6, and
SCF. Our findings suggest that the underlying hematopoietic defect in DBA may
not be limited to the erythroid lineage. Since a fraction of DBA patients have a
deficiency in ribosomal protein S19 (RPS19), we constructed lentiviral vectors
containing the RPS19 gene for overexpression in hematopoietic progenitors from
RPS19-deficient DBA patients. Enforced expression of the RPS19 transgene
improved the proliferation of CD34(+) cells from DBA patients with RPS19
mutation. Similarly, enforced expression of RPS19 improved erythroid development
of RPS19-deficient hematopoietic progenitors as determined by colony assays and
erythroid differentiation cultures. These findings suggest that gene therapy for
RPS19-deficient DBA is feasible. Mutations in the ribosomal protein (RP)S19 gene have been found in about 25% of
the cases of Diamond-Blackfan anemia (DBA), a rare congenital hypoplastic anemia
that includes variable physical malformations. Various mutations have been
identified in the RPS19 gene, but no investigations regarding the effect of
these alterations on RPS19 mRNA levels have been performed. It is well
established that mutated mRNA containing a premature stop codon (PTC) or lacking
a stop codon can be rapidly degraded by specific mechanisms called nonsense
mediated decay (NMD) and nonstop decay. To study the involvement of such
mechanisms in DBA, we analyzed immortalized lymphoblastoid cells and primary
fibroblasts from patients presenting different kinds of mutations in the RPS19
gene, generating allelic deletion, missense, nonsense, and nonstop messengers.
We found that RPS19 mRNA levels are decreased in the cells with allelic deletion
and, to a variable extent, also in all the cell lines with PTC or nonstop
mutations. Further analysis showed that translation inhibition causes a
stabilization of the mutated RPS19 mRNA. Our findings indicate that NMD and
nonstop decay affect the expression of mutated RPS19 genes; this may help to
clarify genotype-phenotype correlations in DBA. The gene encoding the ribosomal protein S19 (RPS19) is frequently mutated in
Diamond-Blackfan anemia (DBA), a congenital erythroblastopenia. The consequence
of these mutations on the onset of the disease remains obscure. Here, we show
that RPS19 plays an essential role in biogenesis of the 40S small ribosomal
subunit in human cells. Knockdown of RPS19 expression by siRNAs impairs 18S rRNA
synthesis and formation of 40S subunits and induces apoptosis in HeLa cells.
Pre-rRNA processing is altered, which leads to an arrest in the maturation of
precursors to the 18S rRNA. Under these conditions, pre-40S particles are not
exported to the cytoplasm and accumulate in the nucleoplasm of the cells in
perinuclear dots. Consistently, we find that ribosome biogenesis and nucleolar
organization is altered in skin fibroblasts from DBA patients bearing mutations
in the RPS19 gene. In addition, maturation of the 18S rRNA is also perturbed in
cells from a patient bearing no RPS19-related mutation. These results support
the hypothesis that DBA is directly related to a defect in ribosome biogenesis
and indicate that yet to be discovered DBA-related genes may be involved in the
synthesis of the ribosomal subunits. BACKGROUND AND OBJECTIVES: Diamond-Blackfan anemia (DBA) is a rare congenital
pure red cell aplasia characterized by normochromic macrocytic anemia,
reticulocytopenia, and normocellular bone marrow with a selective deficiency of
erythroid precursors. Ribosomal protein S19 (RPS19), currently the only gene
associated with DBA, is mutated in 25% of DBA patients, but its role in
erythropoiesis is unknown. We attempted to elucidate the importance of RPS19 in
translation in relation to the pathogenesis of DBA.
DESIGN AND METHODS: We measured translation and proliferation rates in
unstimulated and phytohemagglutinin (PHA)-stimulated lymphocytes isolated from
DBA patients, as well as in K562 cells expressing several RPS19 mutants to
directly test the effect of RPS19 mutations on translation. The effect of
leucine on overall translation was also studied.
RESULTS: We found that the level of translation was on average 48-73% of
controls in both unstimulated and PHA-activated DBA lymphocytes irrespective of
mutations in RPS19. The addition of leucine increased the translational level in
RPS19-non-mutated DBA cells, but not in cells with an RPS19 mutation. In
unstimulated DBA cells, proliferation was significantly impaired in both
RPS19-mutated and non-mutated cells, but in both groups could be efficiently
activated by PHA. Studies on K562 cells showed that RPS19 mutations affecting
RPS19 conserved arginines R56Q and R62Q could significantly inhibit the rate of
protein synthesis, indicating the importance of RPS19 in translation.
INTERPRETATION AND CONCLUSIONS: Our results indicate that inefficient
translation may be the main cause of DBA, and administration of leucine may be
beneficial for at least some DBA patients. Diamond-Blackfan anemia (DBA) is a rare congenital red-cell aplasia
characterized by anemia, bone-marrow erythroblastopenia, and congenital
anomalies and is associated with heterozygous mutations in the ribosomal protein
(RP) S19 gene (RPS19) in approximately 25% of probands. We report identification
of de novo nonsense and splice-site mutations in another RP, RPS24 (encoded by
RPS24 [10q22-q23]) in approximately 2% of RPS19 mutation-negative probands. This
finding strongly suggests that DBA is a disorder of ribosome synthesis and that
mutations in other RP or associated genes that lead to disrupted ribosomal
biogenesis and/or function may also cause DBA. The gene encoding the small subunit ribosomal protein 19 (RPS19) is mutated in
about 25% of cases of the bone marrow failure syndrome Diamond Blackfan Anemia
(DBA), a childhood disease characterized by failure of red cell production. In
these cases DBA is inherited as an autosomal domit trait and RPS19
haploinsufficiency is thought to cause the disease. To study the molecular
pathogenesis of DBA we used siRNA to decrease the level of RPS19 in two human
cell lines, HeLa cells and U-2 OS osteosarcoma cells. Cells with reduced RPS19
levels showed a dramatic reduction in the amounts of small 40S ribosome subunits
and mature 80S ribosomes and an excess of large 60S subunits. These cells were
defective in 18S rRNA production and accumulated 21S and 20S nuclear pre-rRNA
molecules, suggesting that RPS19 is required for specific steps in rRNA
processing. RPS19 depletion produced a reduction in steady-state levels of RPS6
and RPS16 via a post-transcriptional mechanism while the levels of RPL7 and
RPL26 were unaltered, indicating that levels of ribosomal proteins are
determined by subunit assembly. This has interesting implications for the
pathogenesis of DBA suggesting that deficiency of any of the RPS proteins might
have a similar effect and thus may be responsible for causing DBA. Finally in
cell lines from DBA patients with mutations we find increased levels of 21S rRNA
precursors but no abnormality in the ribosome profile on sucrose gradients or in
the steady-state levels of RPS19 suggesting that some cells can partially
compensate for the loss of one allele of RPS19. We conclude that defects in
ribosome biogenesis may underlie the pathology of Diamond Blackfan Anemia. BACKGROUND: Mutations in the ribosomal protein S19 gene (RPS19) have been found
in 25% of patients with Diamond-Blackfan anemia, a rare syndrome of congenital
bone marrow failure characterized by erythroblastopenia and various
malformations. Mechanistic understanding of the role of RPS19 in normal
erythropoiesis and in the Diamond-Blackfan anemia defect is still poor. However,
defective ribosome biogenesis and, in particular, impaired 18S ribosomal RNA
maturation have been documented in association with various identified RPS19
mutations. Recently, new genes, all encoding ribosomal proteins, have been found
to be mutated in Diamond-Blackfan anemia, adding further support to the concept
that ribosome biogenesis plays an important role in regulating erythropoiesis.
We previously showed variability in the levels of expression and subcellular
localization of a subset of RPS19 mutant proteins.
DESIGN AND METHODS: To define the mechanistic basis for this variability better,
we studied a large number of mutant proteins and characterized both RPS19
expression level using a specific antibody against RPS19 and RPS19 subcellular
localization after transfection of Cos-7 cells with various green fluorescent
protein-RPS19 mutants. To investigate the role of the proteasome in RPS19
degradation, we examined the effect of various proteasome inhibitors, namely
lactacystin, MG132, and bortezomib on RPS19 expression and subcellular
localization
RESULTS: We found two distinct classes of RPS19 protein defects in
Diamond-Blackfan anemia based on the stability of the mutant proteins: (i)
slightly decreased to normal levels of expression and normal nucleolar
localization and (ii) markedly deficient expression and failure to localize to
the nucleolus. All the proteasome inhibitors tested were able to restore the
expression levels and normal subcellular localization of several unstable mutant
proteins.
CONCLUSIONS: Our findings demonstrate an important role for the proteasomal
degradation pathway in regulating the expression levels and nucleolar
localization of certain mutant RPS19 proteins in Diamond-Blackfan anemia. Diamond Blackfan anemia (DBA) is an inherited erythroblastopenia associated with
mutations in at least 8 different ribosomal protein genes. Mutations in the gene
encoding ribosomal protein S19 (RPS19) have been identified in approximately 25%
of DBA families. Most of these mutations disrupt either the translation or
stability of the RPS19 protein and are predicted to cause DBA by
haploinsufficiency. However, approximately 30% of RPS19 mutations are missense
mutations that do not alter the stability of the RPS19 protein and are
hypothesized to act by a domit negative mechanism. To formally test this
hypothesis, we generated a transgenic mouse model expressing an RPS19 mutation
in which an arginine residue is replaced with a tryptophan residue at codon 62
(RPS19R62W). Constitutive expression of RPS19R62W in developing mice was lethal.
Conditional expression of RPS19R62W resulted in growth retardation, a mild
anemia with reduced numbers of erythroid progenitors, and significant inhibition
of terminal erythroid maturation, similar to DBA. RNA profiling demonstrated
more than 700 dysregulated genes belonging to the same pathways that are
disrupted in RNA profiles of DBA patient cells. We conclude that RPS19R62W is a
domit negative DBA mutation. This study was aimed to explore the mutations of ribosomal protein (RP) genes in
patients with Diamond Blackfan anemia (DBA). Twenty-one cases of DBA admitted in
our hospital from Dec 2008 to Aug 2012 were screened by PCR for mutations in the
nine known genes associated with DBA: RPS19, RPS24, RPS17, RPL5, RPL11, RPS7,
RPL35a, RPS10 and RPS26. The results found that 8 patients (38.1%) with DBA had
mutations in the genes coding for ribosomal protein, in which RPS19 mutation was
identified in 3 patients, RPS24, RPS7, RPL5, RPL11 and RPL35A mutations were
identified respectively in 1 of the patient. No mutations were detected in
RPS17, RPS10 or RPS26 genes. Thumb anomalies were found in 2 patients with RPL11
or RPL5 mutation, and hypospadias was found in 1 patient with RPS19 mutation. It
is concluded that the mutation frequency of the genes coding for ribosomal
protein in the patients with DBA here is lower than that in western countries.
The hypospadias can be observed in some patients with RPS19 mutation and some
dactyl anomalies are associated with RPL11 and RPL5 mutations. Diamond-Blackfan anemia (DBA) is a rare inherited bone marrow failure syndrome
that is characterized by pure red-cell aplasia and associated physical
deformities. It has been proven that defects of ribosomal proteins can lead to
this disease and that RPS19 is the most frequently mutated gene in DBA patients.
Previous studies suggest that p53-dependent genes and pathways play important
roles in RPS19-deficient embryos. However, whether there are other vital factors
linked to DBA has not been fully clarified. In this study, we compared the whole
genome RNA-Seq data of zebrafish embryos injected with RPS19 morpholino (RPS19
MO), RPS19 and p53 morpholino simultaneously (RPS19+p53 MO) and control
morpholino (control). We found that genes enriched in the functions of
hematological systems, nervous system development and skeletal and muscular
disorders had significant differential expression in RPS19 MO embryos compared
with controls. Co-inhibition of p53 partially alleviates the abnormalities for
RPS19-deficient embryos. However, the hematopoietic genes, which were
down-regulated significantly in RPS19 MO embryos, were not completely recovered
by the co-inhibition of p53. Furthermore, we identified the genome-wide
p53-dependent and -independent genes and pathways. These results indicate that
not only p53 family members but also other factors have important impacts on
RPS19-deficient embryos. The detection of potential pathogenic genes and
pathways provides us a new paradigm for future research on DBA, which is a
systematic and complex hereditary disease. Diamond-Blackfan anemia (DBA) is a congenital bone marrow failure syndrome
characterized by hypoproliferative anemia, associated physical malformations and
a predisposition to cancer. DBA has been associated with mutations and deletions
in the large and small ribosomal protein genes, and genetic aberrations have
been detected in ∼50-60% of patients. In this study, nine Korean DBA patients
were screened for mutations in eight known DBA genes (RPS19, RPS24, RPS17,
RPS10, RPS26, RPL35A, RPL5 and RPL11) using the direct sequencing method.
Mutations in RPS19, RPS26 and RPS17 were detected in four, two and one patient,
respectively. Among the mutations detected in RPS19, two mutations were novel
(c.26T>A, c.357-2A>G). For the mutation-negative cases, array-CGH analysis was
performed to identify copy-number variations, and no deletions involving the
known DBA gene regions were identified. The relative mRNA expression of RPS19
estimated using real-time quantitative PCR analysis revealed two- to fourfold
reductions in RPS19 mRNA expression in three patients with RPS19 mutations, and
p53 protein expression analysis by immunohistochemistry showed variable but
significant nuclear staining in the DBA patients. In conclusion, heterozygous
mutations in the known DBA genes RPS19, RPS26 and RPS17 were detected in seven
out of nine Korean DBA patients. Among these patients, RPS19 was the most
frequently mutated gene. In addition, decreased RPS19 mRNA expression and p53
overexpression were observed in the Korean DBA patients, which supports the
hypothesis that haploinsufficiency and p53 hyperactivation represent a central
pathway underlying the pathogenesis of DBA. Author information:
(1)Program in Genetics and Genome Biology, Research Institute, The Hospital for
Sick Children, Toronto, Canada.
(2)Division of Haematology/Oncology, CancerCare Manitoba, Winnipeg, Canada.
(3)Division of Haematology/Oncology, Children's Hospital of Eastern Ontario,
Ottawa, Canada.
(4)Division of Haematology/Oncology, IWK Health Centre, Halifax, Canada.
(5)Division of Haematology/Oncology, CHU Sainte Justine, Montreal, Canada.
(6)Division of Haematology/Oncology, Alberta Children's Hospital, Calgary,
Canada.
(7)Division of Haematology/Oncology, McMaster Children's Hospital, Hamilton,
Canada.
(8)Division of Haematology/Oncology, Montreal Children's Hospital, Montreal,
Canada.
(9)Division of Haematology/Oncology, British Columbia Children's Hospital,
Vancouver, Canada.
(10)Division of Haematology/Oncology, University of Saskatchewan, Saskatoon,
Canada.
(11)Division of Haematology/Oncology, Queen's University, Kingston, Canada.
(12)Division of Haematology/Oncology, Janeway Child Health Centre, St. John's,
Canada.
(13)Division of Haematology/Oncology, Children's Hospital of Western Ontario,
London, Canada.
(14)Department of Haematology and Internal Medicine, Princess Margaret Hospital,
Toronto, Canada.
(15)Division of Haematology/Oncology, University of Alberta Health Sciences
Centre, Edmonton, Canada.
(16)Division of Haematology/Oncology, Centre Y Sante L'Estrie-Fleur, Sherbrooke,
Canada.
(17)Division of Haematology/Oncology, Centre Hospitalier de l'Université Laval,
Quebec City, Canada.
(18)Division of Haematology/Oncology, King Faisal Specialist Hospital and
Research Center, Riyadh, Saudi Arabia.
(19)The Marrow Failure and Myelodysplasia Program, Haematology Section, Division
of Haematology/Oncology, Department of Paediatrics, The Hospital for Sick
Children, Toronto, Canada.
(20)Program in Child Health and Evaluative Medicine, Research Institute, The
Hospital for Sick Children, Toronto, Canada.
(21)Lymphoma Leukemia Section, Division of Haematology/Oncology, Department of
Paediatrics, The Hospital for Sick Children, Toronto, Canada.
(22)Institute of Medical Sciences, University of Toronto, Toronto, Canada. |
What type of sequences do enhancers evolve from? | Studies have identified enhancers that were pivotal for morphological divergence and highlighted how novel genetic networks shaping form emerged from pre-existing ones.Most of the recently evolved enhancers arise from ancestral dna exaptation , rather than lineage-specific expansions of repeat elements. | The sequences of some gene regulatory elements diverge considerably, even
between closely related species. A detailed analysis of the fast-evolving
sparkling enhancer in Drosophila now identifies key compensatory mechanisms and
'grammar' elements that are critical for maintaining functional integrity. Author information:
(1)University of Cambridge, Cancer Research UK Cambridge Institute, Robinson
Way, Cambridge, CB2 0RE, UK.
(2)European Molecular Biology Laboratory, European Bioinformatics Institute,
Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK.
(3)Department of Biological Sciences, University of Illinois at Chicago (UIC),
845 West Taylor Street, Chicago, IL 60607, USA.
(4)UK Cetacean Strandings Investigation Programme (CSIP) and Institute of
Zoology, Zoological Society of London, Outer Circle, Regent's Park, London NW1
4RY, UK.
(5)School of Optometry and Vision Sciences, Cardiff University, Maindy Road,
Cardiff CF24 4HQ, UK.
(6)UCLA Center for Neurobehavioral Genetics, 695 Charles E. Young Drive South,
Los Angeles, CA 90095, USA.
(7)Division of Stem Cell Biology and Developmental Genetics, MRC National
Institute for Medical Research, Mill Hill, London NW7 1AA, UK.
(8)Center for Zoo and Wild Animal Health, Copenhagen Zoo, Roskildevej 38,
DK-2000 Frederiksberg, Denmark.
(9)Department of Veterinary Medicine, University of Cambridge, Madingley Road,
Cambridge CB3 0ES, UK.
(10)European Molecular Biology Laboratory, European Bioinformatics Institute,
Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD, UK; Wellcome Trust
Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge, CB10 1SD,
UK. Electronic address: [email protected].
(11)University of Cambridge, Cancer Research UK Cambridge Institute, Robinson
Way, Cambridge, CB2 0RE, UK; Wellcome Trust Sanger Institute, Wellcome Trust
Genome Campus, Hinxton, Cambridge, CB10 1SD, UK. Electronic address:
[email protected]. A central goal of evolutionary biology is to understand the genetic origin of
morphological novelties-i.e. anatomical structures unique to a taxonomic group.
Elaboration of morphology during development depends on networks of regulatory
genes that activate patterned gene expression through transcriptional enhancer
regions. We summarize recent case studies and genome-wide investigations that
have uncovered diverse mechanisms though which new enhancers arise. We also
discuss how these enhancer-originating mechanisms have clarified the history of
genetic networks underlying diversification of genital structures in flies,
limbs and neural crest in chordates, and plant leaves. These studies have
identified enhancers that were pivotal for morphological divergence and
highlighted how novel genetic networks shaping form emerged from pre-existing
ones. |
What nerve is involved in carpal tunnel syndrome? | Carpal tunnel syndrome (CTS) is a focal compressive neuropathy of the median nerve at the level of the wrist. | The carpal tunnel syndrome is a neuropathy due to trapping (focal lesion of the
peripheral nerve due to a local cause); in this case, the median nerve is the
most commonly involved. Its presentation is characteristic in females about 40
years of age. The diagnosis is mainly based on clinical features and is
confirmed by electrical criteria. In the anamnesis it is important to consider
systemic diseases as causing the abnormality. Treatment depends on the etiology.
It may be medical or surgical. In the present article we report three cases with
different etiology and treatment. We also review the syndrome. Carpal tunnel syndrome is a complex of symptoms as a result of compression of
the median nerve in the carpal tunnel. As nerve entrapment induces impairment of
somatic fibres followed by clinical symptoms and signs of the syndrome, one can
assume that sympathetic fibres are involved too. Results of studies focused on
this problem show presence of sympathetic symptoms in about half of patients,
including Raynaud phenomenon, blanching of hands, painful swelling of fingers,
dry or excessive sweating of palms. Activity of sympathetic system can be
investigated by means of sympathetic skin response and vasomotor response. Eight
papers presenting the results of sympathetic skin response from median nerve in
carpal tunnel syndrome were analysed. Results of 4 studies showed decreased
sympathetic activity, in 2 findings were equivocal and 2 studies failed to
reveal any abnormalities. The following variables were considered in the
interpretation of sympathetic skin response curve: amplitude, latency and area
under the chart, each of them having limited diagnostic value due to inter-and
intrasubject variation of these parameters. Vasomotor response was investigated
in 2 studies by means of Doppler ultrasound flow examination in digital
arteries. Results of both studies showed decreased vasomotor response in carpal
tunnel syndrome. The review of current knowledge on sympathetic impairment in
carpal tunnel syndrome fails to provide a definitive determination of its range
and clinical consequences. It confirms, however, that routine examination of
sympathetic disturbances is unnecessary due to their minor clinical
significance. OBJECTIVES: To define the relationship between body indices of healthy adults
and cross-sectional areas of the carpal tunnel and median nerve and to obtain
the nerve/tunnel index, which represents a new standard for diagnosing carpal
tunnel syndrome using sonography.
METHODS: Body indices (height, weight, and body mass index) were analyzed in 60
healthy adults, and electromyography and sonography were also performed. The
cross-sectional areas of the proximal and distal median nerve and carpal tunnel
were obtained by sonography. The proximal and distal nerve/tunnel indices were
obtained by calculating the ratio between the proximal and distal
cross-sectional areas of the median nerve to those of the carpal tunnel and
multiplying the value by 100.
RESULTS: Although the proximal cross-sectional areas of the median nerve and
body indices showed statistically significant relationships with weak positive
correlations, the proximal and distal areas of the carpal tunnel showed
relatively stronger correlations with body indices. Between sexes, there were
significant differences in the proximal median nerve cross-sectional area (mean
± SD: male, 10.48 ± 3.21 mm(2); female, 8.81 ± 3.21 mm(2); P < .05) and proximal
carpal tunnel area (male, 182.50 ± 21.15 mm(2); female, 151.23 ± 21.14 mm(2); P
< .05). There was no difference in the proximal nerve/tunnel index (male, 5.80%
± 1.72%; female, 5.91% ± 1.63%). There was a statistically significant
difference in the distal carpal tunnel cross-sectional area (male, 138.90 ±
20.95 mm(2); female, 121.50 ± 18.99 mm(2); P < .05) between sexes, but the
distal median area (male, 9.99 ± 3.42 mm(2); female, 8.46 ± 1.84 mm(2)) and
distal nerve/tunnel index (male, 7.15% ± 2.00%; female, 7.01% ± 1.38%) showed no
significant differences. The proximal index was significantly higher than the
distal index (proximal, 5.85% ± 1.66%; distal, 7.08% ± 1.71%).
CONCLUSIONS: The nerve/tunnel index is unaffected by body indices or sex and
thus may be a useful and objective standard for diagnosing carpal tunnel
syndrome. Carpal tunnel syndrome (CTS) is the most common median nerve neuropathy,
accounting for 90% of all neuropathies. Carpal tunnel syndrome presents in 3.8%
of the general population, with a higher prevalence among women. There are
several risk factors associated with CTS, including both medical and non medical
factors. The pathophysiologic mechanisms involved in the median nerve
compression and traction are thought to be complex, and as yet are not fully
understood. The present review aimed to provide an overview of the
pathophysiology of median nerve neuropathy in the carpal tunnel, and subsequent
development of CTS. BACKGROUND: In this study, it was aimed to determine whether median nerve
epineurectomy is beneficial in the surgical management of carpal tunnel syndrome
(CTS).
MATERIALS AND METHODS: The study enrolled 72 patients including 34 patients
without epineurectomy (Group A) and 38 patients with epineurectomy (Group B).
Surgery was performed in patients with severe electrodiagnostic CTS findings,
CTS duration >1 year and flattening along with hypervascularization in median
nerve. All patients were assessed by visual analog scale, two-point
discrimination test as well as subjective and objective findings at baseline and
on the months 1, 3, and 6 after surgery.
RESULTS: The mean age was 58.3 years (42-75 years) in 38 patients who underwent
an epineurectomy, whereas it was 61.5 years (41-82 years) in 34 patients who did
not have an epineurectomy. The groups were similar with regard to age, gender,
duration of symptoms, and preoperative physical findings. Mean visual analog
scale (VAS) scores were 1.7 in Group A and 1.8 in Group B. Again, these
differences were not significant, on physical examination, the average two-point
discrimination in the distribution of the median nerve was 4.9 mm (range: 3-11
mm) in Group A and 5.3 mm (range: 3-10 mm) in Group B. In postoperative
evaluations, there was a better improvement in visual analog scale scores,
two-point discrimination test and subjective symptoms including dysesthesia,
pain and nocturnal pain within first 3 months; however, there was no marked
difference in objective and subjective findings on the 6th month. No
complication or recurrence was observed.
CONCLUSION: We believe that median nerve epineurectomy is unnecessary in the
surgical management of primary CTS since it has no influence on the midterm
outcomes. Dear sir, one of the most common entrapment neuropathy syndromes in clinical
practice is "Entrapment of median nerve in carpal tunnel" also called "Carpal
tunnel syndrome (CTS)" (Aydin et al., 2007; Huisstede et al., 2010). This
syndrome is caused by entrapment of the median nerve in the wrist (Preston and
Shapiro, 2005) when the pressure increases in the carpal tunnel. A high division
of the median nerve proximal to the carpal tunnel, also known as a bifid median
nerve, is a rare anatomic variation that may be associated with CTS and with
persistent median vessels (Lanz, 1977). This anatomic variation has an incidence
of 0,8% to 2,3% in patients with CTS. Lanz (1977) has characterized this
anatomic condition of the median nerve in the carpal tunnel. These anatomic
variants have been classified into four groups: - Group 0: extraligamentous
thenar branch (standard anatomy); - Group 1: variations of the course of the
thenar branch; - Group 2: accessory branches at the distal portion of the carpal
tunnel; - Group 3: divided or duplicated median nerve inside the carpal tunnel;
- Group 4: accessory branches proximal to the carpal tunnel. During dissection
of the wrist performed for the treatment of a CTS under local anesthesia, we
found an anatomical variation of the median nerve that was divided in two
branches inside the carpal tunnel (Group 3 of Lanz Classification) and in which
its radial branch passed through its own compartment. The two parts of the nerve
seems to be unequal in size (Fig. 1). Moreover the nerve passed in carpal tunnel
associated with a median artery, so we classified this variation in the group 3b
of Lanz Classification (Fig. 2). The persistence of median artery coexisting
with a bifid median nerve has been widely reported in surgical literature (Lanz,
1977; Barbe et al., 2005). Before surgical intervention clinical evaluation of
patient and electrophysiological examination showed no differences compared to a
non bifid median nerve entrapment syndrome. In conclusion the bifid median nerve
may facilitate compression of median nerve in the carpal tunnel because of its
increased cross sectional area even if it has no electrophysiological or
clinical differential diagnosis in case of CTS. The aim of this letter is aware
the physicians in order to borne in mind the possible presence of a median nerve
variation during dissection of carpal tunnel in order to avoid the damage of
this non common anatomical structures. BACKGROUND: Ultrasound is an established method of viewing the median nerve in
the carpal tunnel syndrome (CTS). There is some evidence to suggest that
immediate changes may occur in the median nerve before and after hand activity.
The evidence for the validity and reliability of ultrasound for testing acute
changes in the median nerve has not been systematically reviewed to date.
AIMS: To evaluate the evidence for visible change in ultrasound appearance of
the median nerve after hand activity.
METHODS: A literature search was designed, and three reviewers independently
selected published research for inclusion. Two reviewers independently appraised
papers using the Evidence Based Library and Information Practice (EBLIP)
appraisal checklist, while the third reviewer resolved discrepancies between
appraisals.
RESULTS: Ten studies were appraised and the results showed an increase in median
nerve cross-sectional area following activity, with a return to normal size
within 1 h following activity. Both healthy individuals and those diagnosed with
CTS participated, all were small convenience samples. Ultrasonographic
measurements of the median nerve were reliable in the four studies reporting
this, and the studies demonstrated high quality.
CONCLUSIONS: Good-quality evidence as identified by the EBLIP appraisal
checklist suggests that following hand activity, the median nerve changes in
size in the carpal tunnel. The results may not be generalizable to all people
and activities due to the use of small convenience sampling and narrow range of
activities studied, in all of the studies appraised. Carpal tunnel syndrome (CTS) is a focal compressive neuropathy of the median
nerve at the level of the wrist. CTS is the most common type of compressive
neuropathy that occurs in the upper extremity. Typically, patients with CTS have
paresthesia, pain, and numbness in the radial three and one-half digits.
Nighttime symptoms are more common earlier in the disease process, with daytime
symptoms becoming more frequent as CTS progresses. Electrodiagnostic studies may
be performed to confirm a diagnosis of CTS or to obtain a baseline before
surgical treatment; however, electrodiagnostic studies may be normal in a subset
of patients who have CTS. Patients who have mild CTS should undergo an initial
trial of nonsurgical treatment that includes lifestyle modifications, nighttime
splinting, and corticosteroid injections. Carpal tunnel release should be
performed in patients in whom nonsurgical treatment fails and patients who have
acute CTS secondary to infection or trauma or have advanced symptoms.
Recalcitrant CTS, which may occur in as many as 25% of patients who undergo
carpal tunnel release, most commonly results from an incomplete transverse
carpal ligament release or an incorrect initial diagnosis. Patients with
recurrent symptoms often have perineural fibrosis that tethers the median nerve. BACKGROUND: Compression of the median nerve at the wrist, or carpal tunnel
syndrome, is the most commonly recognized nerve entrapment syndrome. Carpal
tunnel syndrome is usually caused by compression of the median nerve due to
synovial swelling, tumor, or anomalous anatomical structure within the carpal
tunnel.
METHODS: During a routine carpal tunnel decompression, a large vessel was
identified within the carpal tunnel.
RESULTS: The large vessel was the radial artery. It ran along the radial aspect
of the carpal tunnel just adjacent to the median nerve.
CONCLUSIONS: The unusual presence of the radial artery within the carpal tunnel
could be a contributing factor to the development of carpal tunnel syndrome. In
this case, after surgical carpal tunnel release, all symptoms of carpal tunnel
syndrome resolved. |
What is the function of LOX proteins in the ECM? | Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine substrates to reactive aldehydes. The best-studied role of LOX enzymes is the remodeling of the extracellular matrix (ECM) in animals by cross-linking collagens and elastin | Lysyl oxidases (LOX) are copper-dependent enzymes that oxidize primary amine
substrates to reactive aldehydes. The best-studied role of LOX enzymes is the
remodeling of the extracellular matrix (ECM) in animals by cross-linking
collagens and elastin, although intracellular functions have been reported as
well. Five different LOX enzymes have been identified in mammals, LOX and
LOX-like (LOXL) 1 to 4, showing a highly conserved catalytic carboxy terminal
domain and more divergence in the rest of the sequence. Here we have surveyed a
wide selection of genomes in order to infer the evolutionary history of LOX. We
identified LOX proteins not only in animals, but also in many other eukaryotes,
as well as in bacteria and archaea - which reveals a pre-metazoan origin for
this gene family. LOX genes expanded during metazoan evolution resulting in two
superfamilies, LOXL2/L3/L4 and LOX/L1/L5. Considering the current knowledge on
the function of mammalian LOX isoforms in ECM remodeling, we propose that
LOXL2/L3/L4 members might have preferentially been involved in making
cross-linked collagen IV-based basement membrane, whereas the diversification of
LOX/L1/L5 forms contributed to chordate/vertebrate-specific ECM innovations,
such as elastin and fibronectin. Our work provides a novel view on the evolution
of this family of enzymes. Lysyl oxidase (LOX) is an extracellular matrix (ECM)-modifying enzyme that has
been involved in cardiovascular remodeling. We explore the impact of LOX
inhibition in ECM alterations induced by obesity in the cardiovascular system.
LOX is overexpressed in the heart and aorta from rats fed a high-fat diet (HFD).
β-Aminopropionitrile (BAPN), an inhibitor of LOX activity, significantly
attenuated the increase in body weight and cardiac hypertrophy observed in HFD
rats. No significant differences were found in cardiac function or blood
pressure among any group. However, HFD rats showed cardiac and vascular fibrosis
and enhanced levels of superoxide anion (O2(-)), collagen I and transforming
growth factor β (TGF-β) in heart and aorta and connective tissue growth factor
(CTGF) in aorta, effects that were attenuated by LOX inhibition. Interestingly,
BAPN also prevented the increase in circulating leptin levels detected in HFD
fed animals. Leptin increased protein levels of collagen I, TGF-β and CTGF, Akt
phosphorylation and O2(-) production in both cardiac myofibroblasts and vascular
smooth muscle cells in culture, while LOX inhibition ameliorated these
alterations. LOX knockdown also attenuated leptin-induced collagen I production
in cardiovascular cells. Our findings indicate that LOX inhibition attenuates
the fibrosis and the oxidative stress induced by a HFD on the cardiovascular
system. The reduction of leptin levels by BAPN in vivo and the ability of this
compound to inhibit leptin-induced profibrotic mediators and ROS production in
cardiac and vascular cells suggest that interactions between leptin and LOX
regulate downstream events responsible for myocardial and vascular fibrosis in
obesity. |
Please list 3 diseases treated with Valtrex(valacyclovir) | Valtrex (valacyclovir) is an antiviral medication used to treat infections with: herpes zoster (shingles), herpes simplex genitalis (genital herpes),
and herpes labialis (cold sores). | Valaciclovir (Valtrex), the L-valyl ester of acyclovir, is undergoing clinical
development for the treatment and suppression of herpesviral diseases. The
absolute bioavailability of acyclovir from valaciclovir and the metabolic
disposition of valaciclovir were investigated with healthy volunteers in two
separate studies. In a randomized, crossover study, 12 fasting healthy
volunteers each received 1,000 mg of oral valaciclovir and a 1-h intravenous
infusion of 350 mg of acyclovir. The mean absolute bioavailability of acyclovir
was 54.2%, a value three to five times that obtained previously with oral
acyclovir. A similar estimate of 51.3% was made from urinary recovery of
acyclovir. In the second study, four fasting volunteers received a single oral
dose of 1,000 mg of [14C]valaciclovir. The majority of plasma radioactivity was
accounted for by acyclovir, with very low plasma valaciclovir concentrations
(mean maximum concentration of drug in plasma = 0.19 microM), which were
undetectable after 3 h postdose. By 168 h, more than 90% of the administered
radioactive dose was recovered, with approximately 45% in urine and 475 in
feces. More than 99% of the radioactivity recovered in urine corresponded to
acyclovir and its known metabolites, 9-(carboxymethoxymethyl)guanine and
8-hydroxy-9- [(2-hydroxyethoxy)methyl]guanine, with valaciclovir accounting for
less than 0.5% of the dose. Acyclovir, but no valaciclovir, was detected in
fecal samples. These studies show that after oral administration to humans,
valaciclovir is rapidly and virtually completely converted to acyclovir to
provide a high level of acyclovir bioavailability in comparison with that
following oral administration of acyclovir. The plasma acyclovir exposure
obtained following oral administration of valaciclovir is similar to that
achieved with doses of intravenous acyclovir, which are effective in the
treatment and suppression of the less susceptible herpesviral diseases. BACKGROUND: Genital herpes and herpes labialis are prevalent, physically and
psychologically painful, and often disabling. Herpes zoster is often very
painful and may result in months or years of postherpetic neuralgia (PHN). Over
the past two decades, the treatment of these conditions has been transformed by
guanosine nucleoside antivirals such as valacyclovir (Valtrex, a highly
bioavailable prodrug of acyclovir (Zovirax, and famciclovir (Famvir), a highly
bioavailable prodrug of penciclovir (Denavir).
OBJECTIVE: We describe the pharmacology, pharmacokinetics, and clinical efficacy
of valacyclovir for the treatment of herpes simplex, herpes zoster, and other
viral infections. Valacyclovir is also compared with acyclovir and famciclovir.
METHODS: All published literature containing the word "valacyclovir" was
reviewed and summarized.
RESULTS: Valacyclovir is the only oral antiviral agent approved for therapy of
herpes labialis, the only antiviral drug approved for a 3-day course in the
episodic treatment of recurrent genital herpes, as well as the only antiviral
drug approved for once daily dosing for suppressive therapy. In herpes zoster,
valacyclovir is more effective than acyclovir and equally effective as
famciclovir at hastening the healing of zoster-associated pain and PHN.
CONCLUSION: Valacyclovir is safe and effective in the therapy of patients with
herpes simplex and herpes zoster and may be useful in other viral infections. Acyclovir (Zovirax) was approved for the treatment of herpesvirus infections
almost two decades ago. It was the first agent in a novel group of antiviral
medications that now include valacyclovir (Valtrex), penciclovir (Denavir and
famciclovir (Famvir). These agents have made a dramatic impact on the morbidity
associated with herpes simplex virus infections and herpes zoster. Topical and
oral antiviral use have shown modest but statistically significant efficacy in
treating herpes labialis with most studies demonstrating a significant reduction
in episode length and/or healing time. Oral acyclovir, valacyclovir and
famciclovir are efficacious and safe for the treatment of the first episode and
recurrent genital herpes and are useful as suppressive therapy for individuals
with frequent genital herpes recurrences. In addition, high doses of oral
acyclovir, valacyclovir and famciclovir have been shown to speed the healing of
herpes zoster, and data suggests that these agents also decrease associated
acute and chronic pain in people of 50 years of age or older. Further research
is required to clarify the safety of these agents in pregt women with genital
herpes, the role of antiviral therapy in decreasing the sexual transmission of
genital herpes, and the efficacy and cost-effectiveness of these agents in
treating herpes zoster in people below the age of 50 years. Postherpetic neuralgia (PHN) is a serious complication of herpes zoster that has
a predilection for older individuals. PHN is often associated with significant
morbidity, and it can cause insomnia, fatigue, depression and interference with
daily activities in affected individuals. Treatment for PHN is initiated with
antivirals during the acute herpes zoster outbreak. Acyclovir (Zoviraxr,
GlaxoSmithKline), valacyclovir (Valtrex, GlaxoSmithKline) or famciclovir
(Famvir, Novartis) can be used to treat herpes zoster, and all three have been
shown to reduce the duration of the herpetic rash and zoster-associated pain.
These antivirals are most effective when used within the first 72 hours of the
onset of the rash. Side-effects of these antivirals are low and include nausea,
vomiting, abdominal pain and headache. Other treatment options for PHN include
topical analgesics, opioid analgesics, tricyclic antidepressants and gabapentin.
Because of the complexity of PHN, most patients require a combination of
treatment modalities for adequate pain relief. An 83-year-old Japanese man had a 29-year history of well-controlled diabetes
mellitus. His HbA1c level was approximately 6.0%, with no microalbuminuria and a
serum creatinine level seven days before admission of 0.8 mg/dl (eGFR: 69.67
ml/min/1.73 m(2)). Five days before admission, he visited an ophthalmologist
with inflammation of the right palpebra and conjunctiva and began taking
valacyclovir at a dose of 3,000 mg for the treatment of herpes zoster. Two days
before admission, he was prescribed loxoprofen at a dose of 180 mg for a
headache. One day prior to admission, he developed dysarthria, wandering and
loss of appetite. He was subsequently admitted to our hospital with progressive
deterioration of consciousness (Japan Coma Scale: II-20). On admission, he
exhibited renal dysfunction, with a serum creatinine level of 5.11 mg/dl (eGFR:
9.16 ml/min/1.73 m(2)). Based on his diverse symptoms and current treatment with
valacyclovir, the patient was diagnosed with acyclovir-induced neurotoxicity and
his symptoms rapidly improved after hemodialysis. The serum acyclovir level on
admission was found to be 9.25 μg/ml. Although acyclovir-induced neurotoxicity
is commonly seen in elderly patients with renal dysfunction, there are also
reports of this condition in patients with a normal renal function. Valacyclovir
is frequently prescribed to the elderly to treat diseases such as herpes zoster.
As valacyclovir induces renal dysfunction, which raises the serum acyclovir
level to the toxic range, special attention must be paid when administering this
drug in elderly subjects. |
Which olfactory gene senses androsterone? | A previously reported association between the olfactory receptor or7d4 and the androstenone was not detected until we specifically typed this gene p = 1.1 × 10 -4.Any mammals can decipher these scent codes to discern the gender , age , endocrine status , social status , and genotype of conspecifics using dedicated sensory receptors in their olfactory system. | Twin pairs and their siblings rated the intensity of the odorants amyl acetate,
androstenone, eugenol, Galaxolide, mercaptans, and rose (N = 1573). Heritability
was established for ratings of androstenone (h (2) = 0.30) and Galaxolide (h(2)
= 0.34) but not for the other odorants. Genome-wide association analysis using
2.3 million single nucleotide polymorphisms indicated that the most significant
association was between androstenone and a region without known olfactory
receptor genes (rs10966900, P = 1.2 × 10(-7)). A previously reported association
between the olfactory receptor OR7D4 and the androstenone was not detected until
we specifically typed this gene (P = 1.1 × 10(-4)). We also tested these 2
associations in a second independent sample of subjects and replicated the
results either fully (OR7D4, P = 0.00002) or partially (rs10966900, P = 0.010; N
= 266). These findings suggest that 1) the perceived intensity of some but not
all odorants is a heritable trait, 2) use of a current genome-wide marker panel
did not detect a known olfactory genotype-phenotype association, and 3)
person-to-person differences in androstenone perception are influenced by OR7D4
genotype and perhaps by variants of other genes. We explored genetic influences on the perception of taste and smell stimuli.
Adult twins rated the chemosensory aspects of water, sucrose, sodium chloride,
citric acid, ethanol, quinine hydrochloride, phenylthiocarbamide (PTC),
potassium chloride, calcium chloride, cinnamon, androstenone, Galaxolide™,
cilantro, and basil. For most traits, individual differences were stable over
time and some traits were heritable (h(2) from 0.41 to 0.71). Subjects were
genotyped for 44 single nucleotide polymorphisms within and near genes related
to taste and smell. The results of these association analyses confirmed previous
genotype-phenotype results for PTC, quinine, and androstenone. New associations
were detected for ratings of basil and a bitter taste receptor gene, TAS2R60,
and between cilantro and variants in three genes (TRPA1, GNAT3, and TAS2R50).
The flavor of ethanol was related to variation within an olfactory receptor gene
(OR7D4) and a gene encoding a subunit of the epithelial sodium channel (SCNN1D).
Our study demonstrates that person-to-person differences in the taste and smell
perception of simple foods and drinks are partially accounted for by genetic
variation within chemosensory pathways. |
Where in the body would the navicular bone be found? | The navicular bone is located in the foot | A 16-year-old boy developed left foot pain of unknown cause that was
unresponsive to conservative treatment, associated with fever and difficulty
walking. He was admitted to our hospital with osteomyelitis of the accessory and
body of the navicular bone. Surgery could not be performed because the patient
had been diagnosed with Wiskott-Aldrich syndrome. After antibiotic therapy,
laboratory abnormalities and pain had resolved. One year after treatment, the
patient had returned to his original level of sports activity. Both an accessory
navicular and the body of the navicular bone may develop osteomyelitis in
immunocompromised patients; early diagnosis is important for prescribing
effective conservative treatment. |
Name an lncRNA associated with dilated cardiomyopathy. | The lncRNA H19 is significantly upregulated in the myocardial tissue in dilated cardiomyopathy. | |
Which gene is responsible for red hair? | Variants of the melanocyte-stimulating hormone receptor gene are associated with red hair and fair skin in humans. | Cutaneous pigmentation is a major determit of the cutaneous response to
ultraviolet radiation, and consequently of the risk of developing skin cancer.
Over the past 10 years, several genes involved in melanogenesis have been
identified, including the melanocortin 1 receptor gene. Recent work on the
melanocortin 1 receptor suggests that it is a key player in determining whether
eumelanin or pheomelanin is predomitly produced both in vitro and in vivo. In
the mouse, variants of this receptor, which differ in their ability to activate
adenylyl cyclase, are associated with different coat colors. In humans,
melanocortin 1 receptor variants are associated with red hair and fair skin, and
work in progress from our laboratory suggests that certain melanocortin 1
receptor variants may preferentially be associated with hair color rather than
skin type. In addition, melanocortin 1 receptor variants are a risk factor,
possibly independent of skin type, for melanoma susceptibility. The melanocortin 1 receptor, a seven pass transmembrane G protein coupled
receptor, is a key control point in melanogenesis. Loss-of-function mutations at
the MC1R are associated with a switch from eumelanin to phaeomelanin production,
resulting in a red or yellow coat colour. Activating mutations, in animals at
least, lead to enhanced eumelanin synthesis. In man, a number of
loss-of-function mutations in the MC1R have been described. The majority of
red-heads (red-haired persons) are compound heterozygotes or homozygotes for up
to five frequent loss-of-function mutations. A minority of redheads are,
however, only heterozygote. The MC1R is, therefore, a major determit of sun
sensitivity and a genetic risk factor for melanoma and non-melanoma skin cancer.
Recent work suggests that the MC1R also shows a clear heterozygote effect on
skin type, with up to 30% of the population harbouring loss-of-function
mutations. Activating mutations of the MC1R in man have not been described. The
MC1R is particularly informative and a tractable gene for studies of human
evolution and migration. In particular, study of the MC1R may provide insights
into the lightening of skin colour observed in most European populations. The
world wide pattern of MC1R diversity is compatible with functional constraint
operating in Africa, whereas the greater allelic diversity seen in non-African
populations is consistent with neutral predictions rather than selection.
Whether this conclusion is as a result of weakness in the statistical testing
procedures applied, or whether it will be seen in other pigment genes will be of
great interest for studies of human skin colour evolution. Variants of the melanocortin 1 receptor (MC1R) gene are common in individuals
with red hair and fair skin, but the relative contribution to these pigmentary
traits in heterozygotes, homozygotes and compound heterozygotes for variants at
this locus from the multiple alleles present in Caucasian populations is
unclear. We have investigated 174 individuals from 11 large kindreds with a
preponderance of red hair and an additional 99 unrelated redheads, for MC1R
variants and have confirmed that red hair is usually inherited as a recessive
characteristic with the R151C, R160W, D294H, R142H, 86insA and 537insC alleles
at this locus. The V60L variant, which is common in the population may act as a
partially penetrant recessive allele. These individuals plus 167 randomly
ascertained Caucasians demonstrate that heterozygotes for two alleles, R151C and
537insC, have a significantly elevated risk of red hair. The shade of red hair
frequently differs in heterozygotes from that in homozygotes/compound
heterozygotes and there is also evidence for a heterozygote effect on beard hair
colour, skin type and freckling. The data provide evidence for a dosage effect
of MC1R variants on hair as well as skin colour. To determine whether the Agouti Signalling Protein (ASP) gene is associated with
skin and hair coloration in humans, the complete coding region of ASP was
screened for polymorphisms. Analysis of ASP in Caucasian, African-American,
Spanish Basque, Hispanic, Apache and Australian Aboriginal populations revealed
no amino acid substitutions. A single polymorphism in the 3' untranslated region
occurred at a frequency of 0.2 in African-Americans. Variants of the
Melanocortin 1 Receptor (MC1R) gene have been found to be associated with red
hair and fair skin in humans. Red hair individuals are usually compound
heterozygotes or homozygous for one of a number of MC1R polymorphisms associated
with red hair. Some individuals however are heterozygous for only one of these
polymorphisms and dizygotic twins can be concordant for MC1R variants but
discordant for hair colour. A recent study has also identified rare redheads
carrying no MC1R variants indicating that polymorphisms of the human MC1R gene
are required but not sufficient for the red hair phenotype. To address the
question of whether ASP also contributes to the red hair phenotype, individuals
previously identified as having unexpected MC1R genotypes were screened for
polymorphisms at the ASP locus. No polymorphisms were found in any of these
individuals. Results indicate that the human ASP gene is unlikely to function in
normal human pigmentation in the same way as MC1R. We describe a minisequencing protocol for screening DNA samples for the presence
of 12 mutations in the human melanocortin 1 receptor gene (MC1R), eight of which
are associated with the red hair phenotype. A minisequencing profile which shows
homozygosity for one of these mutations or the presence of two different
mutations would strongly indicate that the sample donor is red haired. The
absence of any red hair causing mutations would indicate that the sample donor
does not have red hair. We report the frequencies of MC1R variants in the
British red haired population. Red hair in humans is associated with variant alleles of the alphaMSH receptor
gene, MC1R. Loss of MC1R function in other mammals results in red or yellow hair
pigmentation. We show that a mouse bacterial artificial chromosome (BAC) which
contains Mc1r will efficiently rescue loss of Mc1r in transgenic mice, and that
overexpression of the receptor suppresses the effect of the endogenous
antagonist, agouti protein. We engineered the BAC to replace the mouse coding
region with the human MC1R sequence and used this in the transgenic assay. The
human receptor also efficiently rescued Mc1r deficiency, and in addition,
appeared to be completely resistant to the effects of agouti, suggesting agouti
protein may not play a role in human pigmentary variation. Three human variant
alleles account for 60% of all cases of red hair. We engineered each of these in
turn into the BAC and find that they have reduced, but not completely absent,
function in transgenic mice. Comparison of the phenotypes of alphaMSH-deficient
mice and humans in conjunction with this data suggests that red hair may not be
the null phenotype of MC1R. The heterogeneous group of disorders known as oculocutaneous albinism (OCA)
shares cutaneous and ocular hypopigmentation associated with common
developmental abnormalities of the eye. Mutations of at least 11 loci produce
this phenotype. The majority of affected individuals develop some cutaneous
melanin; this is predomitly seen as yellow/blond hair, whereas fewer have
brown hair. The OCA phenotype is dependent on the constitutional pigmentation
background of the family, with more OCA pigmentation found in families with
darker constitutional pigmentation, which indicates that other genes may modify
the OCA phenotype. Sequence variation in the melanocortin-1 receptor (MC1R) gene
is associated with red hair in the normal population, but red hair is unusual in
OCA. We identified eight probands with OCA who had red hair at birth. Mutations
in the P gene were responsible for classic phenotype of oculocutaneous albinism
type 2 (OCA2) in all eight, and mutations in the MC1R gene were responsible for
the red (rather than yellow/blond) hair in the six of eight who continued to
have red hair after birth. This is the first demonstration of a gene modifying
the OCA phenotype in humans. The melanocortin 1 receptor (Mc1r) plays a central role in cutaneous biology,
but is expressed at very low levels by a small fraction of cells in the skin. In
humans, loss-of-function MC1R mutations cause fair skin, freckling, red hair,
and increased predisposition to melanoma; in mice, Mc1r loss-of-function is
responsible for the recessive yellow mutation, associated with pheomelanic hair
and a decreased number of epidermal melanocytes. To better understand how Mc1r
signaling affects different cutaneous phenotypes, we examined large-scale
patterns of gene expression in different skin components (whole epidermal
sheets, basal epidermal cells and whole skins) of neonatal (P2.5) normal and
recessive yellow mice, starting with a 26K mouse cDNA microarray. From c. 17 000
genes whose levels could be accurately measured in neonatal skin, we identified
883, 2097 and 552 genes that were uniquely expressed in the suprabasal
epidermis, basal epidermis and dermis, respectively; specific biologic roles
could be assigned for each class. Comparison of normal and recessive yellow mice
revealed 69 differentially expressed genes, of which the majority had not been
previously implicated in Mc1r signaling. Surprisingly, many of the
Mc1r-dependent genes are expressed in cells other than melanocytes, even though
Mc1r expression in the skin is confined almost exclusively to epidermal
melanocytes. These results reveal new targets for Mc1r signaling, and point to a
previously unappreciated role for a Mc1r-dependent paracrine effect of
melanocytes on other components of the skin. The Melanocortin-1 Receptor (MC1R) is a G-protein coupled receptor, which is
responsible for production of the darker eumelanin pigment and the tanning
response. The MC1R gene has many polymorphisms, some of which have been linked
to variation in pigmentation phenotypes within human populations. In particular,
the p.D84E, p.R151C, p.R160W and p.D294 H alleles have been strongly associated
with red hair, fair skin and increased skin cancer risk. These red hair colour
(RHC) variants are relatively well described and are thought to result in
altered receptor function, while still retaining varying levels of signaling
ability in vitro. The mouse Mc1r null phenotype is yellow fur colour, the
p.R151C, p.R160W and p.D294 H alleles were able to partially rescue this
phenotype, leading to the question of what the true null phenotype of MC1R would
be in humans. Due to the rarity of MC1R null alleles in human populations, they
have only been found in the heterozygous state until now. We report here the
first case of a homozygous MC1R null individual, phenotypic analysis indicates
that red hair and fair skin is found in the absence of MC1R function. The MC1R gene encodes a protein with key regulatory functions in the melanin
synthesis. A multiplex PCR and a multiplex single base extension protocol were
established for genotyping six exonic MC1R variations highly penetrant for red
hair (R), four exonic MC1R variations weakly penetrant for red hair (r), two
frameshift variations highly penetrant for red hair (R) and three variations in
the promoter region. We genotyped 600 individuals from Denmark using either CE
or MALDI-TOF MS as the detection platform. A total of 62 individuals were
genotyped R/R and among the 62 individuals, 57 had red hair and five had blond
hair colour. Two different R alleles may be located in cis (RR/-) position or
trans (R/R) position, and the phenotype associated with RR/- and R/R may be
different. Two allele-specific PCRs were established with primers targeting the
-G445A variation in the MC1R promoter and the allele-specific PCR products were
used in the multiplex single base extension assay. In all 62 individuals, the
MC1R variants were situated in trans position. Another 18 individuals with red
hair colour were either genotyped R/- or R/r, suggesting that other genes
influence hair colour. BACKGROUND: Red hair color is caused by variants of the melanocortin-1 receptor
(MC1R) gene. People with naturally red hair are resistant to subcutaneous local
anesthetics and, therefore, may experience increased anxiety regarding dental
care. The authors tested the hypothesis that having natural red hair color, a
MC1R gene variant or both could predict a patient's experiencing dental
care-related anxiety and dental care avoidance.
METHODS: The authors enrolled 144 participants (67 natural red-haired and 77
dark-haired) aged 18 to 41 years in a cross-sectional observational study.
Participants completed validated survey instruments designed to measure general
and dental care-specific anxiety, fear of dental pain and previous dental care
avoidance. The authors genotyped participants' blood samples to detect variants
associated with natural red hair color.
RESULTS: Eighty-five participants had MC1R gene variants (65 of the 67
red-haired participants and 20 of the 77 dark-haired participants) (P < .001).
Participants with MC1R gene variants reported significantly more dental
care-related anxiety and fear of dental pain than did participants with no MC1R
gene variants. They were more than twice as likely to avoid dental care as were
the participants with no MC1R gene variants, even after the authors controlled
for general trait anxiety and sex.
CONCLUSION: Dental care-related anxiety, fear of dental pain and avoidance of
dental care may be influenced by genetic variations.
CLINICAL IMPLICATIONS: Dentists should evaluate all patients, but especially
those with naturally red hair, for dental care-related anxiety and use
appropriate modalities to manage the patients' anxiety. Melanocortin receptor 1 (MC1R) and agouti signaling protein (ASIP) are two major
genes affecting coat color phenotypes in mammals, and inactivation mutations in
the MC1R gene are responsible for red coat color in European pig breeds.
Conversely, the gain-of-function ASIP mutations block MC1R signaling and lead to
the production of red pheomelanin. Chinese Tibetan pigs have three types of coat
color phenotypes, including brownish red, solid black and black with patches of
brownish red and white. Herein, we investigated variations of the MC1R and ASIP
genes in Tibetan pigs. The results showed that the brownish red Tibet pig had
the domit black MC1R allele (E(D1)). No loss-of-function mutation in MC1R
responsible for red coat color in European breeds was observed in this breed. No
causal mutation for the red coat color phenotype was found in the coding
sequence of the ASIP gene. A novel missense mutation c.157G > A was firstly
identified in exon 2 of ASIP, which was further genotyped in 285 pigs from five
Chinese breeds and three Western breeds having different coat color phenotypes.
Nearly all pigs were GG homozygotes. In conclusion, no functional variant
responsible for brownish red coloration was found in the coding region of MC1R
and ASIP in Tibetan pigs. INTRODUCTION: The exact reasons for failure of the inferior alveolar nerve (IAN)
block are not completely known, but red hair could play a role. The genetic
basis for red hair involves specific mutations, red hair color (RHC) alleles, in
the melanocortin-1 receptor (MC1R) gene. The purpose of this prospective
randomized study was to investigate a possible link between certain variant
alleles of the MC1R gene or its phenotypic expression of red hair and the
anesthetic efficacy of the IAN block in women.
MATERIALS: One-hundred twenty-four adult female subjects (62 red haired and 62
dark haired) participated in this study. Dental anxiety was determined in each
subject using the Corah Dental Anxiety Questionnaire. The subjects were given 2
cartridges of 2% lidocaine with 1:100,000 epinephrine via the IAN block. Pulpal
anesthesia was measured in the posterior and anterior teeth in 4-minute cycles
for 60 minutes using an electric pulp tester. The MC1R alleles were genotyped
for each subject from cheek cells containing DNA collected using buccal swabs.
RESULTS: Women with red hair and women with 2 RHC alleles reported significantly
higher levels of dental anxiety compared with women with dark hair or women with
0 RHC alleles. No significant differences in anesthetic success were found
between any of the groups for any of the teeth.
CONCLUSIONS: Red hair and the MC1R gene were significantly linked to higher
levels of dental anxiety but were unrelated to success rates of the IAN block in
women with healthy pulps. |
Which bacteria was EcoRI, restriction endonuclease isolated from? | Among hundreds of restriction endonucleases, the Eco R1 enzyme is the most useful and widely investigated enzyme and was isolated from E. coli RY 13 | An endonuclease having EcoRI specificity is produced by bacteria containing the
ColE1 plasmid. Such bacterial cells fail to express restriction or modification
functions in vivo, and phage or plasmid DNA obtained from ColE1-containing cells
has unmodified EcoRI sites that are cleaved in vitro by purified EcoRI
endonuclease or by enzyme extracted from bacteria that carry ColE1. No EcoRI DNA
methylase activity associated with ColE1 has been detected. The finding of
phenotypically cryptic ColE1-dependent EcoRI endonuclease activity and the
absence of any detectable EcoRI modification system in ColE1-containing cells
suggest a control mechanism that appears to prevent functional expression of the
ColE1-determined enzyme in vivo. The restriction endonuclease EcoRI dependent recombination of compatible
plasmids has been studied in RecA cells of Escherichia coli. Plasmid RP4 and the
isogenic ColE1 type plasmids pSA14 or pSA25, differing in
restriction-modification RM EcoRI genes, have been used to study this type of
recombination. EcoRI dependent recombination of plasmids is demonstrated in RecA
cells and, thus, is independent of general system of homologous recombination.
The classes of recombit plasmids isolated from RecA cells differ from the
classes isolated from wild type cells. Levels of tetracycline resistance
conferred by plasmid RP4 are shown to be dependent on the alleles of RecA+ gene,
being extremely low in RecA cells. This property is demonstrated to be useful
for obtaining the multicopy recombit plasmids resulting from EcoRI dependent
recombination in RecA cells of Escherichia coli. Restriction endonucleases play a very important role in genetic engineering and
DNA mapping. Among hundreds of restriction endonucleases, the Eco R1 enzyme is
the most useful and widely investigated enzyme. After sonication and
ultracentrifugation, crude extracts of E. coli RY 13 were purified by employing
the polyethyleneimine precipitate, ammonium sulfate precipitate and heparin
Sepharose-4B affinity column chromatography. The Eco R1 enzyme were purified at
about 42 folds and the specific activity was about 100,000 U/mg of protein. The
whole purification procedure was finished within two days. The recovery was
about 42%. The enzyme was sufficiently concentrated for direct specific DNA
hydrolysis. |
Which is the main reason for the increase in the incidence of cryptococcal disease? | It is an increasing cause of infection in immunosuppressed patients, most notably those with HIV infection. Currently, 4.0% patients with AIDS in the United Kingdom are known to have developed cryptococcosis. The incidence of infection with Cryptococcus neoformans has increased four-fold in the last decade. | Pulmonary cryptococcal infections occur in both immunocompetent and
immunocompromised individuals, with a reported increased incidence of diffuse
pulmonary disease in acquired immune deficiency syndrome (AIDS) patients. The
authors observed no differences in the radiographic appearances of pulmonary
cryptococcal disease between human immunodeficiency virus (HIV) patients and
other immunocompromised individuals. Chest computed tomography (CT) contributes
to a more comprehensive understanding of pulmonary cryptococcal infections. BACKGROUND: Cryptococcus neoformans causes systemic disease in patients with
immunodeficiency. The incidence of cryptococcal meningitis has increased in
parallel with that of HIV infection. Cancer is also a known predisposing factor.
MATERIAL AND METHODS: We present two case reports and a review of the literature
concerning the epidemiology, diagnostics and treatment of cryptococcal
meningitis.
RESULTS: The incidence of cryptococcal meningitis in Scandinavia seems to be
lower than in other parts of the world. Clinical signs and symptoms are often
uncharacteristic. Detection of antigen in spinal fluid is a sensitive and fast
test.
INTERPRETATION: Cryptococcal meningitis is a rare disease, often with
uncharacteristic symptoms. Patients with haematological maligcies have a
higher risk of contracting this disease. It is a differential diagnosis when
neurological symptoms occur in these patients. Despite advances in the treatment of HIV disease, the incidence and mortality of
invasive cryptococcal disease remain significant. A matched, case-control study
was performed to examine the impact of highly active antiretroviral therapy
(HAART) and azole use on the incidence of invasive cryptococcal disease in
HIV-infected patients. The study was performed at a metropolitan hospital with a
large indigent population and an incidence of seven cases of cryptococcal
disease per 1000 persons with AIDS. Bivariate analysis, matched on CD4 count,
revealed that both HAART use [odds ratio (OR) 0.43; 95% confidence interval (CI)
0.23-0.99] and azole use (OR 0.14; 95% CI 0.06-0.34) had a protective effect.
Conditional logistic regression stratified on CD4 lymphocyte count revealed a
protective role for azole use (OR 0.15; 95% CI 0.06-0.40) but not for HAART use
(OR 0.47; 95% CI 0.18-1.26). Of note, the prevalence of HAART use was low in
both cases and controls, with only 12% of cases and 23% of controls on HAART.
The results of this study support previous evidence that azole use prevents
invasive cryptococcal disease. Although current guidelines for the prophylaxis
of opportunistic infections do not suggest routine prophylaxis for cryptococcal
infection, this issue should be reconsidered, especially in populations that
have a low prevalence of HAART use. BACKGROUND: Cryptococcal disease is an opportunistic infection that causes
significant morbidity and mortality in adults with HIV. Primary prophylaxis with
antifungal interventions may decrease cryptococcal disease incidence and
associated mortality.
OBJECTIVES: To assess the efficacy of antifungal interventions for the primary
prevention of cryptococcal disease in adults with HIV.
SEARCH STRATEGY: We searched the following databases: MEDLINE, EMBASE,
Cumulative Index to Nursing and Allied Health Literature (CINAHL),
ClinicalTrials.gov, Database of Abstracts of Reviews of Effectiveness (DARE),
Latin American and Caribbean Literature on the Health Sciences (LILACS), and the
Cochrane Controlled Trials Register (CCTR). We reviewed abstracts from the
following relevant conferences: International AIDS Conference, International
AIDS Society Conference on HIV Pathogenesis and Treatment, and Conference on
Retroviruses and Opportunistic Infections. We searched reference lists for all
primary and other pertinent articles identified. We attempted to contact experts
in the field, particularly primary authors of included studies, to better ensure
completeness of included studies. We also approached pharmaceutical companies
for any available and relevant unpublished data. The time period searched was
from 1980 to August 2004. We placed no language restrictions on the search. Key
words used include: meningitis, cryptococcal, cryptococcus, cryptococcosis,
acquired immunodeficiency syndrome, human immunodeficiency virus, prophylaxis,
chemoprevention, antifungal agents, and the Cochrane screen for randomized
controlled trials.
SELECTION CRITERIA: Randomized controlled trials using antifungal interventions
for the primary prevention of cryptococcal disease in adults with HIV were
selected.
DATA COLLECTION AND ANALYSIS: Two reviewers independently assessed trial
eligibility and quality. Trial authors, experts, and pharmaceutical companies
were contacted for additional and/or missing information. Data were abstracted
by two reviewers. Data were pooled, where appropriate, to yield summary
estimates.
MAIN RESULTS: Five studies (N=1316) were identified. All study patients had CD4
cell counts <300 cells/microl, and the majority of patients had CD4 cell counts
<150 cells/microl. When all five studies are analyzed as a single group
(N=1316), the incidence of cryptococcal disease was decreased in those taking
primary prophylaxis (RR 0.21, 95% CI 0.09, 0.46) compared to those taking
placebo. However, there was no significant difference in overall mortality
observed (RR 1.01, 95% CI 0.71, 1.44). When the three studies using itraconazole
as the intervention were analyzed together (N=798), the incidence of
cryptococcal disease was decreased in those taking itraconazole for primary
prophylaxis (RR 0.12, 95% CI 0.03, 0.51) compared to those taking placebo;
however, there was no significant difference in overall mortality (RR 1.12, 95%
CI 0.70, 1.80). When the two studies using fluconazole as the intervention were
analyzed together (N=518), the incidence of cryptococcal disease was decreased
in those taking fluconazole for primary prophylaxis (RR 0.25, 95% CI 0.07, 0.87)
compared to those taking placebo; however, there was no significant difference
in overall mortality (RR 0.59, 95% CI 0.14, 2.62).
AUTHORS' CONCLUSIONS: Antifungal primary prophylaxis with either itraconazole or
fluconazole is effective in reducing the incidence of cryptococcal disease in
adults with advanced HIV disease. However, neither of these interventions has a
clear effect on overall mortality. Further research is needed to better
understand these interventions and the populations in which they may be most
effective. The objective of this article was to evaluate the epidemiology of cryptococcal
meningitis in Rio de Janeiro State, Brazil, from 1994 to 2004. Six hundred and
ninety-six cases of cryptococcal meningitis were reported, with a mean incidence
of 0.45 per 100,000 inhabitants. Patients were predomitly male; mean age was
35.9 years; AIDS was practically the only underlying disease, reported in 61.2%
of cases; case-fatality was 51.8%. No decline in incidence was observed during
the study period. AIDS is the main predisposing condition for cryptococcal
meningitis, and thus the profile of most patients mirrors that of HIV infection.
Missing information prevented the evaluation of other underlying diseases. Cryptococcal meningitis (CM), a fungal disease caused by Cryptococcus spp., is
the most common form of meningitis and a leading cause of death among persons
with HIV/AIDS in sub-Saharan Africa. Detection of cryptococcal antigen, which is
present several weeks before overt signs of meningitis develop, provides an
opportunity to detect infection early. Screening persons with HIV for
cryptococcal infection when they access healthcare can identify asymptomatic
infected patients allowing for prompt treatment and prevention of death. A newly
developed point-of-care assay for cryptococcal antigen, as well as growing
evidence supporting the utility and cost-effectiveness of screening, are further
reasons to consider broad implementation of cryptococcal screening in countries
with a high burden of cryptococcal disease. |
Which genes are responsible for the high-altitude adaptation of Tibetans? | Recent studies have identified genes involved in high-altitude adaptation in Tibetans. Genetic variants/haplotypes within regions containing three of these genes (EPAS1, EGLN1, and PPARA) are associated with relatively decreased hemoglobin levels observed in Tibetans at high altitude, providing corroborative evidence for genetic adaptation to this extreme environment. A gene (HMOX2) involved in heme catabolism, harbors potentially adaptive variants in Tibetans. | Tibetans have lived at very high altitudes for thousands of years, and they have
a distinctive suite of physiological traits that enable them to tolerate
environmental hypoxia. These phenotypes are clearly the result of adaptation to
this environment, but their genetic basis remains unknown. We report genome-wide
scans that reveal positive selection in several regions that contain genes whose
products are likely involved in high-altitude adaptation. Positively selected
haplotypes of EGLN1 and PPARA were significantly associated with the decreased
hemoglobin phenotype that is unique to this highland population. Identification
of these genes provides support for previously hypothesized mechanisms of
high-altitude adaptation and illuminates the complexity of hypoxia-response
pathways in humans. Modern humans have occupied almost all possible environments globally since
exiting Africa about 100,000 years ago. Both behavioral and biological
adaptations have contributed to their success in surviving the rigors of
climatic extremes, including cold, strong ultraviolet radiation, and high
altitude. Among these environmental stresses, high-altitude hypoxia is the only
condition in which traditional technology is incapable of mediating its effects.
Inhabiting at >3,000-m high plateau, the Tibetan population provides a widely
studied example of high-altitude adaptation. Yet, the genetic mechanisms
underpinning long-term survival in this environmental extreme remain unknown. We
performed an analysis of genome-wide sequence variations in Tibetans. In
combination with the reported data, we identified strong signals of selective
sweep in two hypoxia-related genes, EPAS1 and EGLN1. For these two genes,
Tibetans show unusually high divergence from the non-Tibetan lowlanders (Han
Chinese and Japanese) and possess high frequencies of many linked sequence
variations as reflected by the Tibetan-specific haplotypes. Further analysis in
seven Tibetan populations (1,334 individuals) indicates the prevalence of
selective sweep across the Himalayan region. The observed indicators of natural
selection on EPAS1 and EGLN1 suggest that during the long-term occupation of
high-altitude areas, the functional sequence variations for acquiring biological
adaptation to high-altitude hypoxia have been enriched in Tibetan populations. Some highland populations have genetic adaptations that enable their successful
existence in a hypoxic environment. Tibetans are protected against many of the
harmful responses exhibited by non-adapted populations upon exposure to severe
hypoxia, including elevated hemoglobin concentration (i.e., polycythemia).
Recent studies have highlighted several genes subject to natural selection in
native high-altitude Tibetans. Three of these genes, EPAS1, EGLN1 and PPARA,
regulate or are regulated by hypoxia inducible factor, a principal controller of
erythropoiesis and other organismal functions. Uncovering the molecular basis of
hypoxic adaptation should have implications for understanding hematological and
other adaptations involved in hypoxia tolerance. Because the hypoxia response
involves a variety of cardiovascular, pulmonary and metabolic functions, this
knowledge would improve our understanding of disease mechanisms and could
ultimately be translated into targeted therapies for oxygen deprivation,
cardiopulmonary and cerebral pathologies, and metabolic disorders such as
diabetes and obesity. Recent studies have identified genes involved in high-altitude adaptation in
Tibetans. Genetic variants/haplotypes within regions containing three of these
genes (EPAS1, EGLN1, and PPARA) are associated with relatively decreased
hemoglobin levels observed in Tibetans at high altitude, providing corroborative
evidence for genetic adaptation to this extreme environment. The mechanisms that
afford adaptation to high-altitude hypoxia, however, remain unclear. Considering
the strong metabolic demands imposed by hypoxia, we hypothesized that a shift in
fuel preference to glucose oxidation and glycolysis at the expense of fatty acid
oxidation would improve adaptation to decreased oxygen availability.
Correlations between serum free fatty acid and lactate concentrations in Tibetan
groups living at high altitude and putatively selected haplotypes provide
insight into this hypothesis. An EPAS1 haplotype that exhibits a signal of
positive selection is significantly associated with increased lactate
concentration, the product of anaerobic glycolysis. Furthermore, the putatively
advantageous PPARA haplotype is correlated with serum free fatty acid
concentrations, suggesting a possible decrease in the activity of fatty acid
oxidation. Although further studies are required to assess the molecular
mechanisms underlying these patterns, these associations suggest that genetic
adaptation to high altitude involves alteration in energy utilization pathways. Tibetans are well adapted to high-altitude hypoxic conditions, and in recent
genome-wide scans, many candidate genes have been reported involved in the
physiological response to hypoxic conditions. However, the limited sequence
variations analyzed in previous studies would not be sufficient to identify
causal mutations. Here we conducted resequencing of the entire genomic region
(59.4 kb) of the hypoxic gene EGLN1 (one of the top candidates from the
genome-wide scans) in Tibetans and identified 185 sequence variations, including
13 novel variations (12 substitutions and 1 insertion or deletion). There is a
nonsynonymous mutation (rs186996510, D4E) showing surprisingly deep divergence
between Tibetans and lowlander populations (Fst = 0.709 between Tibetans and Han
Chinese). It is highly prevalent in Tibetans (70.9% on average) but extremely
rare in Han Chinese, Japanese, Europeans, and Africans (0.56-2.27%), suggesting
that it might be the causal mutation of EGLN1 contributing to high-altitude
hypoxic adaptation. Neutrality test confirmed the signal of Darwinian positive
selection on EGLN1 in Tibetans. Haplotype network analysis revealed a
Tibetan-specific haplotype, which is absent in other world populations. The
estimated selective intensity (0.029 for the C allele of rs186996510) puts EGLN1
among the known genes that have undergone the strongest selection in human
populations, and the onset of selection was estimated to have started at the
early Neolithic (∼8,400 years ago). Finally, we detected a significant
association between rs186996510 and hemoglobin levels in Tibetans, suggesting
that EGLN1 contributes to the adaptively low hemoglobin level of Tibetans
compared with acclimatized lowlanders at high altitude. Admixture is recognized as a widespread feature of human populations, renewing
interest in the possibility that genetic exchange can facilitate adaptations to
new environments. Studies of Tibetans revealed candidates for high-altitude
adaptations in the EGLN1 and EPAS1 genes, associated with lower haemoglobin
concentration. However, the history of these variants or that of Tibetans
remains poorly understood. Here we analyse genotype data for the Nepalese
Sherpa, and find that Tibetans are a mixture of ancestral populations related to
the Sherpa and Han Chinese. EGLN1 and EPAS1 genes show a striking enrichment of
high-altitude ancestry in the Tibetan genome, indicating that migrants from low
altitude acquired adaptive alleles from the highlanders. Accordingly, the Sherpa
and Tibetans share adaptive haemoglobin traits. This admixture-mediated
adaptation shares important features with adaptive introgression. Therefore, we
identify a novel mechanism, beyond selection on new mutations or on standing
variation, through which populations can adapt to local environments. Mean hemoglobin (Hb) concentration of about 3 500 subjects derived from 17
studies of Himalayan highlanders (Tibetans, Sherpas, and Ladakhis) was compared
with lowlanders (Chinese Han, Indian Tamils) lived in the Himalayas, and
European climbers during Everest expeditions as well as Andean natives. The
results found that Hb concentration in Himalayan highlanders was systemically
lower than those reported for Andean natives and lowland immigrants. These
comparative data demonstrated that a healthy native population may successfully
reside at high altitude without a significant elevation in Hb, and the lower Hb
levels of Himalayan highlanders than those of migrated lowlanders and Andean
natives are an example of favourable adaptation over the generations. In
addition, excessive polycythemia has frequently been used as a marker of chronic
mountain sickness (CMS). Altitude populations who have a higher Hb concentration
also have a higher incidence of CMS. The low Hb in Himalayans suggested as
showing adaptation over many generations in Tibetan stock. Recent work in Tibet,
suggested that Tibetans there may have adapted to high altitude as a result of
evolutionary pressure selecting for genes which give an advantage at altitude.
All of the population genomic and statistical analysis indicated that EPAS1 and
EGLN1 are mostly likely responsible for high altitude adaptation and closely
related to low Hb concentration in Tibetans. These data supported the hypothesis
that Himalayan highlanders have evolved a genetically different erythropoietic
response to chronic hypoxia by virtue of their much longer exposure to high
altitude. EPAS1 involves in the hypoxic response and is suggested to be responsible for
the genetic adaptation of high-altitude hypoxia in Tibetans. However, the
detailed molecular mechanism remains unknown. In this study, a single nucleotide
polymorphism rs56721780:G>C and an insertion/deletion (indel) polymorphism -742
indel in the promoter region showed divergence between Tibetans and non-Tibetan
lowlanders. rs56721780:G>C regulated the transcription of EPAS1 by IKAROS family
zinc finger 1 (IKZF1), which was identified as a new transcriptional repressor
for EPAS1 gene. It demonstrated that the C allele of rs56721780:G>C decreased
the binding of IKZF1, leading to the attenuated transcriptional repression of
EPAS1 gene. The insertion at -742 indel provided a new binding site for Sp1 and
was related to the activation of EPAS1 promoter. Further functional analysis
revealed that lysyl oxidase (LOX) gene, which was reported to be responsible for
extracellular matrix protein cross-linking of amnion previously, was a direct
target of EPAS1. The CC genotype at rs56721780:G>C and the insertion genotype at
-742 indel were found associated with higher EPAS1 and LOX expression levels in
amnion, as well as higher birth weight of Tibetan newborns, suggesting that
EPAS1 gene might play important roles in the development of amnion, fetus growth
and high-altitude adaptation of Tibetans. Tibetans are well adapted to high-altitude environments. Among the adaptive
traits in Tibetans, the relatively low hemoglobin level is considered a blunted
erythropoietic response to hypoxic challenge. Previously, EPAS1 and EGLN1, the
major upstream regulators in the hypoxic pathway, were reportedly involved in
the hemoglobin regulation in Tibetans. In this study, we report a downstream
gene (HMOX2) involved in heme catabolism, which harbors potentially adaptive
variants in Tibetans. We first resequenced the entire genomic region (45.6 kb)
of HMOX2 in Tibetans, which confirmed the previously suspected signal of
positive selection on HMOX2 in Tibetans. Subsequent association analyses of
hemoglobin levels in two independent Tibetan populations (a total of 1,250
individuals) showed a male-specific association between the HMOX2 variants and
hemoglobin levels. Tibetan males with the derived C allele at rs4786504:T>C
displayed lower hemoglobin level as compared with the T allele carriers.
Furthermore, our in vitro experiments indicated that the C allele of rs4786504
could increase the expression of HMOX2, presumably leading to a more efficient
breakdown of heme that may help maintain a relatively low hemoglobin level at
high altitude. Collectively, we propose that HMOX2 contributes to high-altitude
adaptation in Tibetans by functioning as a modifier in the regulation of
hemoglobin metabolism. |
Which is the main protein in brown adipose tissue (BAT) active in thermogenesis? | Uncoupling protein 1 (UCP1) is the hallmark protein responsible for cold- and diet-induced thermogenesis in brown adipose tissue (BAT). | Brown adipocytes (BAs) are specialized for adaptive thermogenesis and, upon
sympathetic stimulation, activate mitochondrial uncoupling protein (UCP)-1 and
oxidize fatty acids to generate heat. The capacity for brown adipose tissue
(BAT) to protect against obesity and metabolic disease is recognized, yet
information about which signals activate BA, besides β3-adrenergic receptor
stimulation, is limited. Using single-cell transcriptomics, we confirmed the
presence of mRNAs encoding traditional BAT markers (i.e., UCP1, expressed in
100% of BAs Adrb3, expressed in <50% of BAs) in mouse and have shown single-cell
variability (>1000-fold) in their expression at both the mRNA and protein
levels. We further identified mRNAs encoding novel markers, orphan GPCRs, and
many receptors that bind the classic neurotransmitters, neuropeptides,
chemokines, cytokines, and hormones. The transcriptome variability between BAs
suggests a much larger range of responsiveness of BAT than previously recognized
and that not all BAs function identically. We examined the in vivo functional
expression of 12 selected receptors by microinjecting agonists into live mouse
BAT and analyzing the metabolic response. In this manner, we expanded the number
of known receptors on BAs at least 25-fold, while showing that the expression of
classic BA markers is more complex and variable than previously thought. AIMS/HYPOTHESIS: Non-shivering thermogenesis in adipose tissue can be activated
by excessive energy intake or following cold exposure. The molecular mechanisms
regulating this activation have not been fully elucidated. The Janus kinase
(JAK) - signal transducer and activator of transcription (STAT) pathway mediates
the signal transduction of numerous hormones and growth factors that regulate
adipose tissue development and function, and may play a role in adaptive
thermogenesis.
METHODS: We analysed mRNA and protein levels of uncoupling protein 1 (UCP1) and
JAK2 in different adipose depots in response to metabolic and thermal stress.
The in vivo role of JAK2 in adaptive thermogenesis was examined using mice with
adipocyte-specific Jak2 deficiency (A-Jak2 KO).
RESULTS: We show in murine brown adipose tissue (BAT) that JAK2 is upregulated
together with UCP1 in response to high-fat diet (HFD) feeding and cold exposure.
In contrast to white adipose tissue, where JAK2 was dispensable for UCP1
induction, we identified an essential role for BAT JAK2 in diet- and
cold-induced thermogenesis via mediating the thermogenic response to
β-adrenergic stimulation. Accordingly, A-Jak2 KO mice were unable to upregulate
BAT UCP1 following a HFD or after cold exposure. Therefore, A-Jak2 KO mice were
cold intolerant and susceptible to HFD-induced obesity and diabetes.
CONCLUSIONS/INTERPRETATION: Taken together, our results suggest that JAK2 plays
a critical role in BAT function and adaptive thermogenesis. Targeting the
JAK-STAT pathway may be a novel therapeutic approach for the treatment of
obesity and related metabolic disorders. UCP1 and UCP3 are members of the uncoupling protein (UCP) subfamily and are
localized in the inner mitochondrial membrane. Whereas UCP1's central role in
non-shivering thermogenesis is acknowledged, the function and even tissue
expression pattern of UCP3 are still under dispute. Because UCP3 properties
regarding transport of protons are qualitatively identical to those of UCP1, its
expression in brown adipose tissue (BAT) alongside UCP1 requires justification.
In this work, we tested whether any correlation exists between the expression of
UCP1 and UCP3 in BAT by quantification of protein amounts in mouse tissues at
physiological conditions, in cold-acclimated and UCP1 knockout mice.
Quantification using recombit UCP3 revealed that the UCP3 amount in BAT
(0.51ng/(μg total tissue protein)) was nearly one order of magnitude higher than
that in muscles and heart. Cold-acclimated mice showed an approximate three-fold
increase in UCP3 abundance in BAT in comparison to mice in thermoneutral
conditions. Surprisingly, we found a significant decrease of UCP3 in BAT of UCP1
knockout mice, whereas the protein amount in skeletal and heart muscles remained
constant. UCP3 abundance decreased even more in cold-acclimated UCP1 knockout
mice. Protein quantification in UCP3 knockout mice revealed no compensatory
increase in UCP1 or UCP2 expression. Our results do not support the
participation of UCP3 in thermogenesis in the absence of UCP1 in BAT, but
clearly demonstrate the correlation in abundance between both proteins. The
latter is important for understanding UCP3's function in BAT. Uncoupling protein 1 (UCP1) is the hallmark protein responsible for cold- and
diet-induced thermogenesis in brown adipose tissue (BAT). UCP1 activity is
protective against body fat accumulation. UCP1 has re-gained researchers'
attention in the context of obesity following the realization that BAT is
present and can be activated in adult humans and of inducible UCP1-expressing
cells in white fat depots. UCP1-mediated thermogenesis is activated by specific
food compounds, which function by stimulating sympathetic nervous system
activity to adipose tissues and/or by acting on the adipose cells directly or
indirectly, through humoral factors released upon their intake. The impact,
functional consequences and potential mechanism of action of macronutrients,
micronutrients and bioactive compounds impinging on UCP1 expression/activity is
discussed, as well as emerging links between human genetic variation and
differential responses to potential thermogenic food ingredients. Advances in
this field can help dietary recommendations and strategies for long-term weight
loss/maintece and improved metabolic health. Brown adipose tissue (BAT) mitochondria are distinct from their counterparts in
other tissues in that ATP production is not their primary physiologic role. BAT
mitochondria are equipped with a specialized protein known as uncoupling protein
1 (UCP1). UCP1 short-circuits the electron transport chain, allowing
mitochondrial membrane potential to be transduced to heat, making BAT a tissue
capable of altering energy expenditure and fuel metabolism in mammals without
increasing physical activity. The recent discovery that adult humans have
metabolically active BAT has rekindled an interest in this intriguing tissue,
with the overarching aim of manipulating BAT function to augment energy
expenditure as a countermeasure for obesity and the metabolic abnormalities it
incurs. Subsequently, there has been heightened interest in quantifying BAT
function and more specifically, determining UCP1-mediated thermogenesis in BAT
specimens - including in those obtained from humans. In this article, BAT
mitochondrial bioenergetics will be described and compared with more
conventional mitochondria in other tissues. The biochemical methods typically
used to quantify BAT mitochondrial function will also be discussed in terms of
their specificity for assaying UCP1 mediated thermogenesis. Finally, recent data
concerning BAT UCP1 function in humans will be described and discussed. Thermogenesis is an important homeostatic mechanism essential for survival and
normal physiological functions in mammals. Both brown adipose tissue (BAT) (i.e.
uncoupling protein 1 (UCP1)-based) and skeletal muscle (i.e. sarcolipin
(SLN)-based) thermogenesis processes play important roles in temperature
homeostasis, but their relative contributions differ from small to large
mammals. In this study, we investigated the functional interplay between
skeletal muscle- and BAT-based thermogenesis under mild versus severe cold
adaptation by employing UCP1-/- and SLN-/- mice. Interestingly, adaptation of
SLN-/- mice to mild cold conditions (16 °C) significantly increased UCP1
expression, suggesting increased reliance on BAT-based thermogenesis. This was
also evident from structural alterations in BAT morphology, including
mitochondrial architecture, increased expression of electron transport chain
proteins, and depletion of fat droplets. Similarly, UCP1-/- mice adapted to mild
cold up-regulated muscle-based thermogenesis, indicated by increases in muscle
succinate dehydrogenase activity, SLN expression, mitochondrial content, and
neovascularization, compared with WT mice. These results further confirm that
SLN-based thermogenesis is a key player in muscle non-shivering thermogenesis
(NST) and can compensate for loss of BAT activity. We also present evidence that
the increased reliance on BAT-based NST depends on increased autonomic input, as
indicated by abundant levels of tyrosine hydroxylase and neuropeptide Y. Our
findings demonstrate that both BAT and muscle-based NST are equally recruited
during mild and severe cold adaptation and that loss of heat production from one
thermogenic pathway leads to increased recruitment of the other, indicating a
functional interplay between these two thermogenic processes. |
Which method is Proseek based on? | proximity extension immunoassay | BACKGROUND: Systemic lupus erythematosus (SLE) is a remarkably heterogeneous
autoimmune disease. Despite tremendous efforts, our knowledge of serum protein
patterns in severe SLE phenotypes is still limited. We investigated the serum
protein pattern of SLE, with special emphasis on irreversible organ damage and
active lupus nephritis (LN) as assessed by renal Systemic Lupus Erythematosus
Disease Activity Index.
METHODS: We used proximity extension immunoassay (PEA, Proseek Multiplex, Olink)
to assess the serum levels of ninety-two inflammation-related proteins in Czech
patients with SLE (n = 75) and age-matched healthy control subjects (n = 23).
Subgroup analysis was carried out on the basis of organ damage (with/without,
42/33) and biopsy-proven LN (with/without, 27/48; active LN, n = 13; inactive
LN, n = 14).
RESULTS: Of thirty deregulated proteins between SLE and the healthy controls
(Pcorr < 0.05), the top upregulated proteins in SLE were sirtuin 2, interleukin
18 (IL18), and caspase 8 (Pcorr < 0.0006). Of these, sirtuin 2 and caspase 8
had not yet been reported with SLE. Elevated levels of IL8, CCL2/MCP1, CCL11,
and MMP10 (Pcorr < 0.05) were detected in patients with organ damage for which
the serum levels of CCL11 and MMP10 were particularly informative in organ
damage prediction. Comparing patients based on LN, elevated levels of CSF1,
sIL15RA, sCD40, sCX3CL1, caspase 8, sIL18R1, bNGF, and GDNF (Pcorr < 0.05) were
detected in active LN. Except GDNF, all LN-associated markers showed usefulness
in prediction of active renal disease.
CONCLUSIONS: This highly sensitive PEA analysis identified the serum pattern of
SLE, organ damage, and active LN, with many novel candidate proteins detected.
Their exact role and suitability as biomarkers in SLE deserve further
investigation. Serum protein fingerprints associated with MGUS and MM and their changes in MM
after autologous stem cell transplantation (MM-ASCT, day 100) remain unexplored.
Using highly-sensitive Proximity Extension ImmunoAssay on 92 cancer biomarkers
(Proseek Multiplex, Olink), enhanced serum levels of Adrenomedullin (ADM, Pcorr=
.0004), Growth differentiation factor 15 (GDF15, Pcorr= .003), and soluble Major
histocompatibility complex class I-related chain A (sMICA, Pcorr= .023), all
prosurvival and chemoprotective factors for myeloma cells, were detected in MM
comparing to MGUS. Comparison of MGUS and healthy subjects revealed elevation of
angiogenic and antia-poptotic midkine (Pcorr= .0007) and downregulation of
Transforming growth factor beta 1 (TGFB1, Pcorr= .005) in MGUS. Importantly,
altered serum pattern was associated with MM-ASCT compared to paired MM at the
diagnosis as well as to healthy controls, namely by upregulated B-Cell
Activating Factor (sBAFF) (Pcorr< .006) and sustained elevation of other
pro-tumorigenic factors. In conclusion, the serum fingerprints of MM and MM-ASCT
were characteristic by elevated levels of prosurvival and chemoprotective
factors for myeloma cells. |
With which personality traits has the human monoamine oxidase A (MAOA) gene been associated? | Association studies suggest that the low activity variant of the monoamine oxidase A (MAOA)-uVNTR polymorphism confers risk for emotional disturbances associated with antisocial traits, particularly in males. These include antisocial and borderline personality disorders and antisocial aggression. | Heritable factors account for approximately 40-60% of the total variance of
liability to alcohol dependence. The present study tested whether a novel
functional polymorphism in the promotor region of the X-chromosomal monoamine
oxidase A gene (MAOA) was related to antisocial and anxious-depressive traits in
alcoholics. Due to the X-chromosomal localization of the MAOA gene,
psychobiological traits were compared separately for both genders of 298 male
and 66 female alcoholics. In males, 30 of 59 alcoholics with antisocial
personality disorder carried the low-activity 3-repeat allele in contrast to
only 7 of 31 anxious-depressive alcoholics (51% vs. 23%; p = 0.02). Likewise,
female anxious-depressive alcoholics showed a trend towards a low frequency of
genotypes with the 3 repeat allele compared to female alcoholics without these
symptoms (29% vs. 53%; p = 0.09). Taken together, these findings suggest that
the 3-repeat allele of the MAOA polymorphism contributes modestly to the
dimension of overand underreactive behaviors as possible antecedents of
alcoholism. The history of research on the association between platelet monoamine oxidase
(MAO) activity and personality traits, such as sensation seeking and
impulsiveness, is reviewed. The effects of MAO-inhibiting compounds in cigarette
smoke for the interpretation of this association are discussed. Recent results
confirming a true association between platelet MAO activity and personality are
presented. From a clinical point of view, this association has had its greatest
impact on the understanding of the nature of constitutional factors making
individuals vulnerable for e.g. substance abuse and the link between low
platelet MAO activity and type 2 alcoholism, recently confirmed on non-human
primates, is discussed. The molecular mechanisms underlying the association
between platelet MAO and behaviour are discussed and evidence that common
transcriptional factors, e.g. within the AP-2 family, regulating both the
expression of platelet MAO and components of central monoaminergic systems, such
as synthetizing enzymes, receptors and transporters, are presented. A hypothesis
is put forward, that such common transcription factors may not directly regulate
platelet MAO expression, but rather mitochondrial number or outer membrane
surface. BACKGROUND: Allelic variation of the monoamine oxidase A (MAOA) gene has been
implicated in conduct disorder and antisocial, aggressive behavior in humans
when associated with early adverse experiences. We tested the hypothesis that a
repeat polymorphism in the rhesus macaque MAOA gene promoter region influences
aggressive behavior in male subjects.
METHODS: Forty-five unrelated male monkeys raised with or without their mothers
were tested for competitive and social group aggression. Functional activity of
the MAOA gene promoter polymorphism was determined and genotypes scored for
assessing genetic and environmental influences on aggression.
RESULTS: Transcription of the MAOA gene in rhesus monkeys is modulated by an
orthologous polymorphism (rhMAOA-LPR) in its upstream regulatory region. High-
and low-activity alleles of the rhMAOA-LPR show a genotype x environment
interaction effect on aggressive behavior, such that mother-reared male monkeys
with the low-activity-associated allele had higher aggression scores.
CONCLUSIONS: These results suggest that the behavioral expression of allelic
variation in MAOA activity is sensitive to social experiences early in
development and that its functional outcome might depend on social context. Genetic variants of the monoamine oxidase A (MAOA) have been associated with
aggression-, anxiety-, and addiction-related behavior in several nonclinical and
clinical populations. Here, we investigated the influence of allelic variation
of MAOA activity on aggression-related personality traits and disease risk in
patients with personality disorders. Personality disorders were diagnosed with
the Structured Clinical Interview of DSM-IV and were allocated to cluster A, B,
and C. Personality features were assessed by the revised NEO Personality
Inventory and the Tridimensional Personality Questionnaire. The genotype of the
MAOA gene-linked polymorphic region (MAOA-LPR) was determined in 566 patients
with personality disorders and in 281 healthy controls. MAOA genotype was
significantly associated with cluster B personality disorders (chi2=7.77,
p=0.005, df=1) but not with cluster C personality disorders. In total, 26.0% of
cluster B patients were hemi- or homozygous for the low-activity variant of the
MAOA genotype, compared to 16.4% in the control group. Associations between MAOA
variants and personality domains related to impulsivity and aggressiveness were
inconsistent. Our findings further support the notion that allelic variation of
MAOA activity contributes modestly to the balance of hyper-
(impulsive-aggressive) and hyporeactive (anxious-depressive) traits. By conferring allele-specific transcriptional activity on the monoamine oxidase
A (MAOA) gene in humans, length variation of a repetitive sequence [(variable
number of tandem repeat (VNTR)] in the MAOA promoter influences a constellation
of personality traits related to aggressive and antisocial behavior and
increases the risk of neurodevelopmental and psychiatric disorders. Here, we
have analyzed the presence and variability of this MAOA promoter repeat in
several species of nonhuman primates. Sequence analysis of MAOA's
transcriptional control region revealed the presence of the VNTR in chimpanzee
(Pan troglodytes), bonobo (Pan paniscus), gorilla (Gorilla gorilla), orangutan
(Pongo pygmaeus), rhesus macaque (Macaca mulatta) and Gelada baboon
(Theropithecus gelada). The majority of P. troglodytes and P. paniscus showed a
single repeat with a sequence identical to the VNTR sequence in humans. In
contrast, analyses of the remaining species revealed shorter sequences similar
to the first 18 bp of human VNTR. Compared with other nonhuman primates, the
VNTR sequence of M. mulatta showed the highest length variability with allele
frequencies of 35, 25 and 40% for the five, six and seven repeat variants,
respectively. The extent of variability of the MAOA promoter repeat in both
rhesus monkeys and humans supports the notion that there may be a relationship
between functional MAOA expression and aggression-related traits in humans and
rhesus macaque populations. The physiological changes of adolescence may promote risk-taking behaviors,
including binge drinking. Approximately 40% of alcoholics were already drinking
heavily in late adolescence. Most cases of alcoholism are established by the age
of 30 years with the peak prevalence at 18-23 years of age. Therefore the key
time frame for the development, and prevention, of alcoholism lies in
adolescence and young adulthood. Severe childhood stressors have been associated
with increased vulnerability to addiction, however, not all stress-exposed
children go on to develop alcoholism. Origins of resilience can be both genetic
(variation in alcohol-metabolizing genes, increased susceptibility to alcohol's
sedative effects) and environmental (lack of alcohol availability, positive peer
and parental support). Genetic vulnerability is likely to be conferred by
multiple genes of small to modest effects, possibly only apparent in
gene-environment interactions. For example, it has been shown that childhood
maltreatment interacts with a monoamine oxidase A (MAOA) gene variant to predict
antisocial behavior that is often associated with alcoholism, and an interaction
between early life stress and a serotonin transporter promoter variant predicts
alcohol abuse in nonhuman primates and depression in humans. In addition, a
common Met158 variant in the catechol-O-methyltransferase (COMT) gene can confer
both risk and resilience to alcoholism in different drinking environments. It is
likely that a complex mix of gene(s)-environment(s) interactions underlie
addiction vulnerability and development. Risk-resilience factors can best be
determined in longitudinal studies, preferably starting during pregcy. This
kind of research is important for planning future measures to prevent harmful
drinking in adolescence. Association studies suggest that the low activity variant of the monoamine
oxidase A (MAOA)-uVNTR polymorphism confers risk for emotional disturbances
associated with antisocial traits, particularly in males. Here, we assessed the
low (MAOA-L) activity variant in relation to both brain function and a
behavioral index of antisocial traits. From an initial sample of 290 healthy
participants, 210 had low (MAOA-L) or high (MAOA-H) activity variants.
Participants underwent a brief assessment of personality traits and
event-related potential (ERP) recording during an emotion-processing task.
Genotype differences in ERPs were localized using LORETA. The MAOA-L genotype
was distinguished by elevated scores on the index of antisocial traits. These
traits were related to altered ERPs elicited 120-280ms post-stimulus,
particularly for negative emotion. Altered neural processing of anger in MAOA-L
genotypes was localized to medial frontal, parietal, and superior
temporo-occipital regions in males, but only to the superior occipital cortex in
females. The MAOA low activity variant may increase susceptibility to antisocial
traits through alterations to the neural systems for processing threat-related
emotion, especially for males. Monoamines such as noradrenalin and serotonin may
modulate these relationships, given that their metabolism varies according to
MAOA variants, and that they modulate both emotional brain systems and
antisocial aggression. Monoamine Oxidase A (MAOA) is a critical enzyme in the catabolism of
monoaminergic neurotransmitters. MAOA transcriptional activity is thought to be
regulated by a well characterized 30 base pair (bp) variable nucleotide repeat
(VNTR) that lies approximately ∼1000 bp upstream of the transcriptional start
site (TSS). However, clinical associations between this VNTR genotype and
behavioral states have been inconsistent. Herein, we describe a second, 10 bp
VNTR that lies ∼1500 bp upstream of the TSS. We provide in vitro and in silico
evidence that this new VNTR region may be more influential in regulating MAOA
transcription than the more proximal VNTR and that methylation of this CpG-rich
VNTR is genotype dependent in females. Finally, we demonstrate that genotype at
this new VNTR interacts significantly with history of child abuse to predict
antisocial personality disorder (ASPD) in women and accounts for variance in
addition to that explained by the prior VNTR. BACKGROUND: Antisocial personality disorder (ASPD) is characterised by elevated
impulsive aggression and increased risk for criminal behaviour and
incarceration. Deficient activity of the monoamine oxidase A (MAOA) gene is
suggested to contribute to serotonergic system dysregulation strongly associated
with impulsive aggression and antisocial criminality.
AIMS: To elucidate the role of epigenetic processes in altered MAOA expression
and serotonin regulation in a population of incarcerated offenders with ASPD
compared with a healthy non-incarcerated control population.
METHOD: Participants were 86 incarcerated participants with ASPD and 73 healthy
controls. MAOA promoter methylation was compared between case and control
groups. We explored the functional impact of MAOA promoter methylation on gene
expression in vitro and blood 5-HT levels in a subset of the case group.
RESULTS: Results suggest that MAOA promoter hypermethylation is associated with
ASPD and may contribute to downregulation of MAOA gene expression, as indicated
by functional assays in vitro, and regression analysis with whole-blood
serotonin levels in offenders with ASPD.
CONCLUSIONS: These results are consistent with prior literature suggesting MAOA
and serotonergic dysregulation in antisocial populations. Our results offer the
first evidence suggesting epigenetic mechanisms may contribute to MAOA
dysregulation in antisocial offenders. BACKGROUND: Monoamine oxidase-A (MAO-A) is a treatment target in
neurodegenerative illness and mood disorders that increases oxidative stress and
predisposition toward apoptosis. Increased MAO-A levels in prefrontal cortex
(PFC) and anterior cingulate cortex (ACC) occur in rodent models of depressive
behavior and human studies of depressed moods. Extreme dysphoria is common in
borderline personality disorder (BPD), especially when severe, and the molecular
underpinnings of severe BPD are largely unknown. We hypothesized that MAO-A
levels in PFC and ACC would be highest in severe BPD and would correlate with
symptom magnitude.
METHODS: [(11)C] Harmine positron emission tomography measured MAO-A total
distribution volume (MAO-A VT), an index of MAO-A density, in severe BPD
subjects (n = 14), moderate BPD subjects (n = 14), subjects with a major
depressive episode (MDE) only (n = 14), and healthy control subjects (n = 14).
All subjects were female.
RESULTS: Severe BPD was associated with greater PFC and ACC MAO-A VT compared
with moderate BPD, MDE, and healthy control subjects (multivariate analysis of
variance group effect: F6,102 = 5.6, p < .001). In BPD, PFC and ACC MAO-A VT
were positively correlated with mood symptoms (PFC: r = .52, p = .005; ACC: r =
.53, p = .004) and suicidality (PFC: r = .40, p = .037; ACC: r = .38, p = .046),
while hippocampus MAO-A VT was negatively correlated with verbal memory (r =
-.44, p = .023).
CONCLUSIONS: These results suggest that elevated MAO-A VT is associated with
multiple indicators of BPD severity, including BPD symptomatology, mood
symptoms, suicidality, and neurocognitive impairment. Author information:
(1)Isabelle Ouellet-Morin, PhD, School of Criminology, Université de Montréal &
Research Center of the Montreal Mental Health University Institute, Montréal and
Research Group on Child Psychosocial Maladjustment, Université de Montréal,
Montréal, Canada; Sylvana M. Côté, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Department of Social and
Preventive Medicine, Université de Montréal, Montréal, Canada and International
Laboratory for Child and Adolescent Mental Health Development, INSERM U669,
Paris, France; Frank Vitaro, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal and School of Psychoéducation,
Université de Montréal, Montréal, Canada; Martine Hébert, PhD, Department of
Sexology, Université du Québec à Montréal, Montréal, Québec, Canada; René
Carbonneau, PhD, Research Group on Child Psychosocial Maladjustment, Université
de Montréal, Montréal, Canada;Éric Lacourse, PhD, School of Criminology,
Université de Montréal & Research Center of the Montreal Mental Health
University Institute, Montréal, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Canada and Department of
Sociology, Université de Montréal & Research Center of the Sainte-Justine
University Hospital, Montréal, Canada; Gustavo Turecki, MD, PhD, The McGill
Group for Suicide Studies, Douglas Hospital Research Center, Montréal, Québec,
Canada; Richard E. Tremblay, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Canada, International
Laboratory for Child and Adolescent Mental Health Development, INSERM U669,
Paris, France, Department of Pediatrics, Psychiatry and Psychology, Université
de Montréal, Montréal, Canada and School of Public Health, Physiotherapy and
Population Science, University College Dublin, Ireland
[email protected].
(2)Isabelle Ouellet-Morin, PhD, School of Criminology, Université de Montréal &
Research Center of the Montreal Mental Health University Institute, Montréal and
Research Group on Child Psychosocial Maladjustment, Université de Montréal,
Montréal, Canada; Sylvana M. Côté, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Department of Social and
Preventive Medicine, Université de Montréal, Montréal, Canada and International
Laboratory for Child and Adolescent Mental Health Development, INSERM U669,
Paris, France; Frank Vitaro, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal and School of Psychoéducation,
Université de Montréal, Montréal, Canada; Martine Hébert, PhD, Department of
Sexology, Université du Québec à Montréal, Montréal, Québec, Canada; René
Carbonneau, PhD, Research Group on Child Psychosocial Maladjustment, Université
de Montréal, Montréal, Canada;Éric Lacourse, PhD, School of Criminology,
Université de Montréal & Research Center of the Montreal Mental Health
University Institute, Montréal, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Canada and Department of
Sociology, Université de Montréal & Research Center of the Sainte-Justine
University Hospital, Montréal, Canada; Gustavo Turecki, MD, PhD, The McGill
Group for Suicide Studies, Douglas Hospital Research Center, Montréal, Québec,
Canada; Richard E. Tremblay, PhD, Research Group on Child Psychosocial
Maladjustment, Université de Montréal, Montréal, Canada, International
Laboratory for Child and Adolescent Mental Health Development, INSERM U669,
Paris, France, Department of Pediatrics, Psychiatry and Psychology, Université
de Montréal, Montréal, Canada and School of Public Health, Physiotherapy and
Population Science, University College Dublin, Ireland. Violent offending is elevated among individuals with antisocial personality
disorder (ASPD) and high psychopathic traits (PP). Morphological abnormalities
of the amygdala and orbitofrontal cortex (OFC) are present in violent offenders,
which may relate to the violence enacted by ASPD + PP. Among healthy males,
monoamine oxidase-A (MAO-A) genetic variants linked to low in vitro
transcription (MAOA-L) are associated with structural abnormalities of the
amygdala and OFC. However, it is currently unknown whether amygdala and OFC
morphology in ASPD relate to MAO-A genetic polymorphisms. We studied 18 ASPD
males with a history of violent offending and 20 healthy male controls. Genomic
DNA was extracted from peripheral leukocytes to determine MAO-A genetic
polymorphisms. Subjects underwent a T1-weighted MRI anatomical brain scan that
provided vertex-wise measures of amygdala shape and surface area and OFC
cortical thickness. We found that ASPD + PP subjects with MAOA-L exhibited
decreased surface area in the right basolateral amygdala nucleus and increased
surface area in the right anterior cortical amygdaloid nucleus versus healthy
MAOA-L carriers. This study is the first to describe genotype-related
morphological differences of the amygdala in a population marked by high
aggression. Deficits in emotional regulation that contribute to the violence of
ASPD + PP may relate to morphological changes of the amygdala under genetic
control. |
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