مجال
التميز
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تميز دراسي وبحثي
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البحوث المنشورة
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البحث (1):
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عنوان البحث:
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The Role of TLR2 in Cigarette Smoke-Induced Gene
Induction
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رابط إلى البحث:
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Click
here
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تاريخ النشر:
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4th
December,
2013
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موجز عن البحث:
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Abstract
Background: Previous
work form our group has shown that innate immune cells perceive cigarette
smoke as an inflammatory and xenobiotic stimulus, which alters the immune
response to invading pathogens. It is unclear as to the specific cellular and
molecular mechanisms driving cigarette smoke-induced inflammation, but we
have demonstrated that this response is, in part, driven by Toll-Like
Receptor (TLR) 2 in innate immune cells in vitro and in mice in vivo.
Methodology/Principle
findings: To
address the impact TLR2/6, has on cigarette smoke-induced gene induction,
HEK293 cells were permanently transfected with TLR2/6 or Null vector, and
were stimulated with 10% cigarette smoke extract (CSE)for 8 h. Total RNA was
extracted and the transcriptome analysed using Illumina Bead Chip arrays. In
HEK293 Null cells, CSE induced 33 genes and down-regulated 41. In HEK293
TLR2/6 cells, CSE induced 23 genes and down-regulated 44. Further analysis
revealed that 42 genes were regulated in a TLR2/6-dependent manner.
Comparison of these genes with those induced by smoke in human primary
monocytes revealed that 5 were mutually regulated. The major pathways
affected were those associated with anti-oxidant pathways, tumorgenesis and
cell survival.
Conclusions: Our data
suggest that the innate immune receptor TLR2/6 has a critical role for the
expression of a particular cassette of genes induced by cigarette smoke.
Pathway analysis indicates these are related to functions in both cell
survival and tumorgenesis. Future validation of the relative importance of
these pathways using more complex models
is required a may lead to improved understanding of the pathology of
cigarette smoke-induced diseases such as COPD, cardiovascular disease and
cancer.
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البحث (2):
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عنوان البحث:
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Evidence That Links
Loss of Cyclo-Oxygenase-2 With Increased Asymmetric Dimethylarginine: Novel
Explanation of Cardiovascular Side Effects Associated With Anti-inflammatory
Drugs.
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رابط إلى البحث:
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Click
here
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تاريخ النشر:
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November
21, 2014
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موجز عن البحث:
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Background: Cardiovascular side effects associated with
cyclo-oxygenase-2 inhibitor drugs dominate clinical concern.
Cyclo-oxygeanse-2 is expressed in the renal medulla where inhibition causes
fluid retention and increased blood pressure. However, the mechanisms linking
cyclo-oxygeanse-2 inhibition and cardiovascular events are unknown and no
biomarkers have been identified.
Methods and
Results—Transcriptome analysis of wild-type and cyclo-oxygenase-2-/- mouse
tissues revealed 1 gene altered in heart and aorta but >1000 genes in the
renal medulla including those regulating the endogenous NO synthase
inhibitors ADMA and L-NMMA; Cyclo-oxygeanse-2-/- mice had increased plasma
levels of ADMA and L-NMMA and reduced endothelial NO responses. These genes
and methylarginines were not similarly altered in mice lacking prostacyclin
receptors (IP-/-). Wild-type mice or human volunteers taking
cyclo-oxygeanse-2 inhibitors also showed increased plasma ADMA. Endothelial
NO is cardio protective, reducing thrombosis and atherosclerosis.
Consequently, increased ADMA is associated with cardiovascular disease. Thus,
our study identifies ADMA as a biomarker and mechanistic bridge between renal
cyclo-oxygenase-2 inhibition and systemic vascular dysfunction with non-steroidal
anti-inflammatory drug usage.
Conclusions: We
identify the endogenous eNOS inhibitor ADMA as a biomarker and mechanistic
bridge between renal COX-2 inhibition and systemic vascular dysfunction.
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المؤتمرات العلمية:
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المؤتمر (1):
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عنوان المؤتمر:
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The 12
Annual Rocky Mountain Bioinformatics Conference
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تاريخ الإنعقاد:
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12/12/2014
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بلد
ومكان الإنعقاد:
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Aspen
,Colorado, USA
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة
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Generating
Novel Insight into COX-2 Inhibitor Toxicity
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ملخص المشاركة
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Cyclo-oxygenase
(COX)-2 inhibitor drugs such as meloxicam (Mobic) and Ibuprofen (Alleve) are
widely used to treat pain and inflammation. While effective, these drugs
produce substantial side effects including cardiovascular, renal and
gastrointestinal toxicity. In addition certain COX-2 inhibitor drugs are
hepatotoxic, for example, up to 7% of patients receiving meloxicam exhibit
aminotransferase elevations. Mechanisms driving COX-2 inhibitor-associated
toxicity are poorly understood. Here we have set out to find novel pathways
by which COX-2 inhibitors produce toxicity by mining the Open TG-GATEs
database (http://toxico.nibio.go.jp) for data concerning COX-2 inhibitor
drugs. This publically available toxicogenomics dataset contains liver
microarray data from rats treated with 168 pharmaceutical agents. We found
data for 10 COX-2 inhibitor drugs but focused analysis on meloxicam, due its
known effects on the liver. Analysis using LIMMA modified t-test (FC>2,
p<0.05, FDR correction) revealed that meloxicam produced a time-dependent
change in the transcriptome, with 14, 40 and 587 differentially expressed
genes present respectively at 3, 9 and 24 hours. At 3 hours, no specific
pathways were altered. At 9 hours, organo-nitrogen compound response pathways
were enriched, as were response pathways for the inflammatory transcription
factor, nuclear factor kappaB (NFkB). At 24 hours, analysis of genes altered
>5-fold indicated activation of neutrophils and an endotoxin-like
inflammatory response as well as metabolic pathways to organic molecules.
Overall these data, suggest acute meloxicam administration produces an
inflammatory response in the liver, possibly associated with early NFkB
activation and this could contribute to liver and systemic toxicity.
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المؤتمر (2):
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عنوان المؤتمر:
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British
Pharmacological Society
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تاريخ الإنعقاد:
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16/12/2014
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بلد
ومكان الإنعقاد:
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London,
UK
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طبيعة المشاركة:
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Poster
presentation
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عنوان المشاركة
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Using
Online Microarray Data Mining to Establish the Link Between COX-2 and Rgl1, a
Novel Chemopreventative Target for COX-2 Inhibitor Drugs
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ملخص المشاركة
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Introduction:
Cyclo-oxygenase (COX)-2 is the therapeutic target for non-steroidal
anti-inflammatory drugs (NSAIDs) including COX-2 selective drugs such as
celecoxib (CelebrexTM) and meloxicam (MobicTM). NSAIDs are associated with cardiovascular
side effects but have potential in the prevention of cancer. Using a
transcriptomic analysis of tissue from atherosclerotic COX-2-deficient mice
we have previously identified an interaction between COX-2 and the Ral
Guanine Nucleotide Dissociation Stimulator-Like 1 (Rgl1) gene 1 Rgl1 is an
effector of Ras, the most common oncogene in human cancer, which activates
Ral signalling pathways to regulate proliferation and survival.
Down-regulation of Rgl1 may therefore, contribute to the chemopreventative
effects of COX-2 inhibitors. Here we have validated our previous studies by
performing qPCR analysis of Rgl1 expression on a range of tissues from
healthy COX-2-/- mice and mining an online microarray database (Open TGGATEs)
to determine the effect of COX-2 inhibition of Rgl1 expression in a
completely independent dataset.
Methods: RNA was
extracted from kidney, aorta, heart and brain of COX-2-/- mice and wildtype
littermates (n=8, male+female, C57Bl/6 background) and Rgl1 expression
measured by qPCR relative to 18S and GAPDH housekeeping genes. Publically
available microarray data from Open TG-GATEs was downloaded
(http://toxico.nibio.go.jp/). These were from experiments in which RNA was
analysed from liver of rats treated with the COX-2 inhibitor, meloxicam
(0-100mg/kg; in 0.5% methylcellulose; by oral gavage; 24hrs). Once
downloaded, data were quantile normalised and Rgl1 expression data was
produced. Normalised expression at increasing doses was then calculated
versus vehicle treated levels.
Results: Rgl1 was
down-regulated in all studied tissues from healthy COX-2 knockout mice by
qPCR (Figure A) including those known to have high (kidney, brain) and low
(aorta, heart) COX-2 expression. This association was validated using the
Open TG-GATEs dataset. Here, meloxicam was found to produce a dose-dependent
down-regulation of Rg1 expression in rats.
Conclusions: These data
validate the link between COX-2 and Rgl1 in two completely independent data
sets and demonstrate that Rgl1 down-regulation can be achieved by
pharmacological COX-2 inhibition as well as gene disruption. These studies
also demonstrate the power and utility of online microarray database mining
to generate pharmacological insights.
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