مجال
التميز
|
تميز دراسي وبحثي وإبداع علمي
|
البحوث المنشورة
|
|
البحث (1):
|
|
عنوان البحث:
|
Synergistic therapeutic vascular
cytoprotection against complement-mediated injury induced via a PKCα-, AMPK-,
and CREB-dependent pathway.
|
رابط إلى البحث:
|
Click here
|
تاريخ النشر:
|
21 Jan 2014
|
موجز عن البحث:
|
Endothelial injury and dysfunction precede
accelerated arterial disease in allograft vasculopathy and systemic
autoimmune diseases and involve pathogenic Abs and complement. Recent reports
suggest that switching to rapamycin from calcineurin antagonists reduces
posttransplant vasculopathy and prolongs survival following cardiac
transplantion. The majority of these patients also receive statin therapy. We
examined potential mechanisms underlying this protective response in human
endothelial cells and identified synergy between rapamycin and atorvastatin.
Mechanistically, atorvastatin and rapamycin activated a protein kinase Cα,
AMP-activated kinase, and CREB-dependent vasculoprotective pathway, which
induced decay-accelerating factor (DAF) promoter activity via binding to the
cAMP response element, mutation of which attenuated promoter activity. This
response significantly increased endothelial cell surface DAF and enhanced
protection against complement-mediated injury. Synergy with rapamycin was
reproduced by simvastatin, whereas combining atorvastatin with cyclosporine
or mycophenolate in place of rapamycin was ineffective. Importantly, synergy
was reproduced in vivo, in which only atorvastatin and rapamycin therapy in
combination was sufficient to induce DAF on murine aortic endothelium. We
believe this pathway represents an important therapeutically inducible
vasculoprotective mechanism for diseases mediated by pathogenic Abs and complement,
including posttransplant vasculopathy and systemic lupus erythematosus.
Although our study focuses on the vascular endothelium, the findings are
likely to be broadly applicable, given the diverse cellular expression of
DAF.
|
البحث (2):
|
|
عنوان البحث:
|
Shear stress and
VEGF enhance endothelial differentiation of human adipose-derived stem cells.
|
رابط إلى البحث:
|
Click here
|
تاريخ النشر:
|
12 August 2014
|
موجز عن البحث:
|
Herein we combine
chemical and mechanical stimulation to investigate the effects of vascular
endothelial growth factor (VEGF) and physiological shear stress in promoting
the differentiation human adipose derived stem cells (ADSCs) into endothelial
cells. ADSCs were isolated and characterized; endothelial differentiation was
promoted by culturing confluent cells in 50 ng/ml VEGF under physiological
shear stress for up to 14 days. Afterwards, endothelial cells were seeded
onto collagen or acellular aortic valve matrices and exposed to four culture
conditions: shear stress + VEGF; shear stress _ VEGF; static + VEGF and
static _ VEGF. After 7 days, phenotype was investigated. ADSCs subjected to
shear stress and VEGF express a comprehensive range of specific endothelial
markers (vWF, eNOS and FLT-1 after 7 days and CD31, FLk-1 and VE-cadherin
after 14 days) and maintain the phenotype when seeded onto scaffolds. Our
protocol proved to be an efficient source of endothelial-like cells for
tissue engineering based on autologous ADSC.
|
البحث (3):
|
|
عنوان البحث:
|
Methotrexate-mediated activation
of an AMPK-CREB-dependent pathway: a novel mechanism for vascular protection
in chronic systemic inflammation
|
رابط إلى البحث:
|
click
here
|
تاريخ النشر:
|
09 Jan 2015
|
موجز عن البحث:
|
AIM: Premature cardiovascular events
complicate chronic inflammatory conditions. Low-dose weekly methotrexate
(MTX), the most widely used disease-modifying drug for rheumatoid arthritis
(RA), reduces disease-associated cardiovascular mortality. MTX increases
intracellular accumulation of adenosine monophosphate (AMP) and
5-aminoimidazole-4-carboxamide ribonucleotide which activates AMP-activated
protein kinase (AMPK). We hypothesised that MTX specifically protects the
vascular endothelium against inflammatory injury via induction of
AMPK-regulated protective genes.
METHODS/RESULTS:
In the (NZW×BXSB)F1 murine model of
inflammatory vasculopathy, MTX 1 mg/kg/week significantly reduced
intramyocardial vasculopathy and attenuated end-organ damage. Studies of
human umbilical vein endothelial cells (HUVEC) and arterial endothelial cells
(HAEC) showed that therapeutically relevant concentrations of MTX
phosphorylate AMPKαThr172, and induce cytoprotective genes including
manganese superoxide dismutase (MnSOD) and haem oxygenase-1 (HO-1). These
responses were preserved when HUVECs were pretreated with tumour necrosis
factor-α to mimic dysfunctional endothelium. Furthermore, MTX protected
against glucose deprivation-induced endothelial apoptosis. Mechanistically,
MTX treatment led to cyclic AMP response element-binding protein (CREB)Ser133
phosphorylation, while AMPK depletion attenuated this response and the
induction of MnSOD and HO-1. CREB siRNA inhibited upregulation of both
cytoprotective genes by MTX, while chromatin immunoprecipitation demonstrated
CREB binding to the MnSOD promoter in MTX-treated EC. Likewise, treatment of
(NZW×BXSB)F1 mice with MTX enhanced AMPKαThr172 phosphorylation and MnSOD,
and reduced aortic intercellular adhesion molecule-1 expression.
CONCLUSIONS:
These data suggest that MTX
therapeutically conditions vascular endothelium via activation of AMPK-CREB.
We propose that this mechanism contributes to the protection against
cardiovascular events seen in patients with RA treated with MTX.
|
المؤتمرات العلمية:
|
|
المؤتمر (1):
|
|
عنوان المؤتمر:
|
Frontiers in Cardiovascular Biology 2014
|
تاريخ الإنعقاد:
|
July 2014
|
مكان
الإنعقاد:
|
Barcelona, Spain
|
طبيعة المشاركة:
|
Poster Presentation
|
عنوان المشاركة:
|
Celecoxib-mediated activation of an
AMPK-CREB-Nrf2 dependent pathway: a novel mechanism for endothelial
cytoprotection in chronic systemic inflammation
|
ملخص المشاركة:
|
Purpose: Non-steroidal anti-inflammatory
drugs (NSAIDs) are important for controlling pain and inflammation. However,
concerns remain regarding athero-thrombotic risk. Despite this, clinical
evidence suggests that among the COXIBs, celecoxib may have a more positive
cardiovascular profile. In addition to targeting cyclo-oxygenase (COX)-2,
recent evidence suggests that celecoxib also modulates COX-2-independent
cytoprotective signal transduction pathways. We explored the hypothesis that
celecoxib may induce anti-oxidant, anti-inflammatory genes in the vascular
endothelium via AMP kinase (AMPK) activation, and so protect vascular
endothelium against inflammation-mediated injury.
Methods/Results: Human umbilical vein
endothelial cells (HUVECs) were studied to investigate the effect of
celecoxib on the induction of anti-oxidant enzymes. The results indicated
that celecoxib at therapeutically relevant concentrations (1-10µM) induces
anti-oxidant genes, including heme oxygenase-1 (HO-1), manganese superoxide
dismutase (MnSOD) and ferritin heavy chain (p<0.01). However, traditional
NSAIDs (ibuprofen and naproxen) fail to do this. Dimethyl-celecoxib (DMC), a
derivative of celecoxib lacking the COX-2-inhibitory function, reproduced the
effects of celecoxib, suggesting that a COX-2-independent signalling pathway
is responsible for induction of anti-oxidant enzymes. Celecoxib treatment led
to the generation of mitochondrial reactive oxygen species (mROS), and their
role in the induction of HO-1 was confirmed by inhibition following
pre-treatment of HUVEC with the mROS scavenger MitoTempo (p<0.01).
Celecoxib treatment led to phosphorylation of AMPKα(Thr172) and CREB(Ser133)
via a linear pathway, and the subsequent nuclear translocation of
transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). The
induction of HO-1 by celecoxib was inhibited by siRNA-mediated depletion of
AMPKα1, CREB-1, or Nrf2 (p<0.01). Initial functional analysis demonstrated
that celecoxib and DMC inhibit TNF-α-induced vascular cell adhesion
molecule-1 (VCAM-1) expression (p<0.05), a response not seen with
ibuprofen or naproxen.
Conclusion: These data demonstrate the
ability of celecoxib to regulate expression of anti-oxidant genes including
HO-1 and MnSOD, via a novel endothelial mROS-AMPK-CREB-Nrf2-dependent
pathway, and to exert anti-inflammatory cytoprotective effects. We propose
that understanding in detail the mechanisms of action of individual
anti-inflammatory drugs will inform clinical decisions surrounding the
prescription of these drugs, and ultimately lead to the development of more
specific and safer alternatives.
|
المؤتمر (2):
|
|
عنوان المؤتمر:
|
London Vascular Biology Forum
|
تاريخ الإنعقاد:
|
11 Dec 2013
|
مكان
الإنعقاد:
|
London,
UK
|
طبيعة المشاركة:
|
Poster Presentation
|
عنوان المشاركة:
|
Celecoxib-mediated activation of
an AMPK-CREB-Nrf2 dependent pathway: a novel mechanism for endothelial
cytoprotection in chronic systemic inflammation
|
ملخص المشاركة:
|
Non-steroidal anti-inflammatory drugs
(NSAIDs) are important for controlling pain and inflammation. However, there
are concerns about their athero-thrombotic potential. Despite this, some
research and clinical evidence now suggests that, among the COXIBs, celecoxib
has a positive cardiovascular profile. Thus, celecoxib might be more than
simply an anti-inflammatory drug and, if so, could be used as an
athero-protective drug. To date, our study shows that celecoxib induces
anti-oxidant, anti-inflammatory and cyto-protective enzymes in vascular
endothelium. Aside from its anti-inflammatory qualities, evidence is emerging
that suggests that celecoxib can modulate COX-2-independent signal
transduction pathways. I have studied human umbilical vein endothelial cells
(HUVECs) to investigate the effect of celecoxib on the induction of
anti-oxidant enzymes. I have shown that celecoxib upregulates HO-1 and MnSOD
via activation of AMPK, at both the mRNA and protein level. However,
traditional NSAIDs (ibuprofen and naproxen) fail to do this. My results also
indicate an additional cyto-protective action of celecoxib via upregulation
of the complement inhibitory protein decay-accelerating factor (DAF).
Dimethyl-celecoxib (DMC) – a derivative of celecoxib lacking the
cyclooxygenase-2-inhibitory function, reproduced the effects of celecoxib on
HO-1, MnSOD and DAF. Moreover, celecoxib and DMC were able to inhibit
TNF-α-induced VCAM-1 expression. Thus, our results suggest that a
COX-2-independent pathway is required for induction of anti-oxidant enzymes.
Additional experiments demonstrate that celecoxib induces additional phase II
detoxifying and antioxidant genes including NQO-1, thioredoxin, thioredoxin
reductase, UCP-2, and ferritin heavy chain at the mRNA level. These data
demonstrate the ability of celecoxib to induce cytoprotective antioxidant
gene expression in HUVECs. We propose that this response is independent of
COX-2 and requires an increase in mitochondrial reactive oxygen species, AMPK
activation and transcriptional induction mediated via an Nrf2/ARE signalling
pathway.
|
جوائز التكريم:
|
|
الجائزة (1):
|
|
مسمى الجائزة:
|
Special Poster Prize award in Vascular
Sciences Unit Imperial College London
|
الجهة المانحة:
|
41st London Vascular Biology
Forum Joint Event with KCL Stroke Forum
|
تاريخ الجائزة:
|
11 December 2013
|
مجال التكريم:
|
Activation of redox sensitive
AMPK-dependent, Cox-2 independent signalling pathway by celecoxib exerts
anti-inflammatory of NRF2 inducible antioxidant defences in the gliovascular
complex after stroke.
|