Khalid Matrougui - Academia.edu (original) (raw)

Papers by Khalid Matrougui

Orai proteins contribute to Ca2+ entry pathways through store-dependent, Ca2+ release-activated C... more Orai proteins contribute to Ca2+ entry pathways through store-dependent, Ca2+ release-activated Ca2+ (CRAC) channels (Orai1), and store-independent, arachidonic acid (AA)-regulated Ca2+ (ARC) or LeukotrieneC4-regulated Ca2+ (LRC) channels (Orai1 and Orai3). Remarkably, although activated by fundamentally different mechanisms, both CRAC and ARC/LRC channels share a requirement for STIM1 expression. To date the role of endoplasmic reticulum-resident STIM1 (ER-STIM1) in the activation of CRAC channels is well appreciated. There is a minor pool of STIM1 at the plasma membrane (PM-STIM1) that was shown to be necessary for ARC current activation in HEK293 cells. Using pharmacological tools targeting AA synthesis and metabolism, Ca2+ imaging, whole-cell and perforated patch clamp electrophysiological recordings we demonstrate that both Orai1 and Orai3 are required for ARC and LRC current activation in both primary vascular smooth muscle cells (VSMCs) and HEK293 cells. Surprisingly, while P...

Diabetes is increasing in the world and causes severe cardiovascular complications. Diabetes-indu... more Diabetes is increasing in the world and causes severe cardiovascular complications. Diabetes-induced limb ischemia leads to foot amputation and therapeutic remedies are urgently needed. Here we report that local injection of mesenchymal stem cells (MSCs) prestimulated with epidermal growth factor (EGF) restored blood flow and vasculogenesis in the ischemic hind-limb of type II diabetic (db À /db À ) mice. Bone marrow cells from db À /db À mice are altered as evidenced by increased oxidative stress and reduced Akt and adhesion molecules when compared with control (db À /db þ ). Femoral artery ligation-induced ischemia was performed in the hind-limb of db À /db À and db À /db þ mice for 28 days. Enhanced green fluorescent protein (EGFP)-MSCs stimulated±exogenous EGF for 24 h were injected locally into the ischemic muscle. Blood flow measured with MoorLDI-Laser and microangiography assessed with X-ray showed 100% recovery in db À /db þ compared to 50% recovery in db À /db À mice. Interestingly, db À /db À mice had 60 and 96% blood flow recovery and 61 and 98% of vasculogenesis when treated with MSCs alone or MSCs modified with EGF, respectively. Western blot analysis of hind-limb muscles revealed an increase in Akt and vascular endothelial growth factor receptor phosphorylation and hypoxia-inducible factor) expression in db À /db À mice injected with MSCs or MSCs þ EGF compared to db À /db À mice. Fluorescent microscopic images show that EGFP-MSCs differentiate into new microvessels. Adhesion and migration of MSCs on cultured endothelial cells were ICAM1-, VCAM1-and Akt-dependent mechanism and elevated when MSCs were prestimulated with EGF compared with nonstimulated MSCs. Our novel study data provide evidence that in type II diabetes, stimulated MSCs with EGF enhance the recovery of blood flow and angiogenesis.

Arterial hypertension is a major risk factor that can lead to complication of peripheral vascular... more Arterial hypertension is a major risk factor that can lead to complication of peripheral vascular disease due, in part, to endothelial dysfunction. Because sodium nitrite (SN) can be converted to nitric oxide (NO), which counteracts endothelial dysfunction, we explored the effect of nitrite on neovascularization following hind limb ischemia in different models of hypertension (HT). Chronic delivery of angiotensin II (Ang II, 400 ng/kg/min) or N(omega)-nitro-L-arginine-methyl-ester (L-NAME, 0.1 g/L) was used for a 2-week period to induce hypertension. Mice were subjected to femoral artery ligation-induced ischemia in the hind limb followed by treatment with SN (50 mg/L) for 2 weeks. SN significantly reduced systolic arterial blood pressure in mice receiving Ang II and L-NAME but had no effect in sham animals. After 2 weeks, blood flow and microangiography showed 60 %±1.0 recovery in sham compared with 40 %± 1.3 in HT mice. Importantly, sham and HT mice treated with SN showed a 100 % blood flow recovery associated with normalization in capillary density. The inhibition of xanthine-oxido-reductase (allopurinol) or VEGFR (SU-5416) prevented the neovascularization in HT mice treated with SN. Cyclic GMP (cGMP) content in the hind limb was significantly increased in mice treated with SN compared with non-treated mice. Nitrite/nitrate content was only increased in the sham group treated with SN. Immunoprecipitation and Western blot analysis revealed an increase in eNOS/Akt/VEGFR phosphorylation in skeletal muscle from mice treated with SN compared with non-treated mice. Our findings indicate that SN therapy rescues the neovascularization and blood flow recovery in the ischemic hind limb of sham and HT mice likely through the Akt/NO/cGMP and VEGFR pathways.

Journal of Biological Chemistry, 2014

Leukotriene-C4 synthase (LTC4S) generates LTC4 from arachidonic acid metabolism. LTC4 is a proinf... more Leukotriene-C4 synthase (LTC4S) generates LTC4 from arachidonic acid metabolism. LTC4 is a proinflammatory factor that acts on plasma membrane cysteinyl leukotriene receptors. Recently, however, we showed that LTC4 was also a cytosolic second messenger that activated store-independent LTC4-regulated Ca(2+) (LRC) channels encoded by Orai1/Orai3 heteromultimers in vascular smooth muscle cells (VSMCs). We showed that Orai3 and LRC currents were up-regulated in medial and neointimal VSMCs after vascular injury and that Orai3 knockdown inhibited LRC currents and neointimal hyperplasia. However, the role of LTC4S in neointima formation remains unknown. Here we show that LTC4S knockdown inhibited LRC currents in VSMCs. We performed in vivo experiments where rat left carotid arteries were injured using balloon angioplasty to cause neointimal hyperplasia. Neointima formation was associated with up-regulation of LTC4S protein expression in VSMCs. Inhibition of LTC4S expression in injured carotids by lentiviral particles encoding shRNA inhibited neointima formation and inward and outward vessel remodeling. LRC current activation did not cause nuclear factor for activated T cells (NFAT) nuclear translocation in VSMCs. Surprisingly, knockdown of either LTC4S or Orai3 yielded more robust and sustained Akt1 and Akt2 phosphorylation on Ser-473/Ser-474 upon serum stimulation. LTC4S and Orai3 knockdown inhibited VSMC migration in vitro with no effect on proliferation. Akt activity was suppressed in neointimal and medial VSMCs from injured vessels at 2 weeks postinjury but was restored when the up-regulation of either LTC4S or Orai3 was prevented by shRNA. We conclude that LTC4S and Orai3 altered Akt signaling to promote VSMC migration and neointima formation.

Journal of Diabetes & Metabolism, 2011

PLoS ONE, 2009

The aims of this study were to investigate the role of poly(ADP-ribose) polymerase (PARP)-1 in dy... more The aims of this study were to investigate the role of poly(ADP-ribose) polymerase (PARP)-1 in dyslipidemia-associated vascular dysfunction as well as autonomic nervous system dysregulation. Apolipoprotein (ApoE) 2/2 mice fed a high-fat diet were used as a model of atherosclerosis. Vascular and autonomic functions were measured in conscious mice using telemetry. The study revealed that PARP-1 plays an important role in dyslipidemia-associated vascular and autonomic dysfunction. Inhibition of this enzyme by gene knockout partially restored baroreflex sensitivity in ApoE 2/2 mice without affecting baseline heart-rate and arterial pressure, and also improved heart-rate responses following selective blockade of the autonomic nervous system. The protective effect of PARP-1 gene deletion against dyslipidemia-induced endothelial dysfunction was associated with preservation of eNOS activity. Dyslipidemia induced PARP-1 activation was accompanied by oxidative tissue damage, as evidenced by increased expression of iNOS and subsequent protein nitration. PARP-1 gene deletion reversed these effects, suggesting that PARP-1 may contribute to vascular and autonomic pathologies by promoting oxidative tissue injury. Further, inhibition of this oxidative damage may account for protective effects of PARP-1 gene deletion on vascular and autonomic functions. This study demonstrates that PARP-1 participates in dyslipidemiamediated dysregulation of the autonomic nervous system and that PARP-1 gene deletion normalizes autonomic and vascular dysfunctions. Maintenance of eNOS activity may be associated with the protective effect of PARP-1 gene deletion against dyslipidemia-induced endothelial dysfunction.

Journal of Hypertension, 2013

Endothelial dysfunction plays a key role in the development and progression of cardiovascular dis... more Endothelial dysfunction plays a key role in the development and progression of cardiovascular disease. In patients with hypertension, endothelial dysfunction is characterized by a decrease of vasodilator factors release. Recent evidence highlights the involvement of regulatory T cell in the cardiovascular physiology and pathology. An increasing body of data suggest that an imbalance in the immune system triggers inflammation and compromises the cardiovascular homeostasis. In this mini-review, we will highlight the role of immune regulatory T cells in hypertension-induced vascular dysfunction.

Diabetes/Metabolism Research and Reviews, 2014

Background We previously reported that enhanced nuclear factor kappa B (NFκB) activity is respons... more Background We previously reported that enhanced nuclear factor kappa B (NFκB) activity is responsible for resistance arteries dysfunction in type 2 diabetic mice.

Diabetes/Metabolism Research and Reviews, 2008

Type 2 diabetes is associated with microvascular complications. We hypothesized that the sustaine... more Type 2 diabetes is associated with microvascular complications. We hypothesized that the sustained elevated EGFR phosphorylation produces structural wall remodelling and altered mechanical properties of mesenteric resistance artery (MRA) in type 2 diabetes. Freshly isolated MRA (80-100 microm diameter) from type 2 diabetic (db(-)/db(-), diabetic) and non-diabetic (db(-)/db(+), control) mice were subjected to pressure-passive diameter and wall thickness relationships; western blot analysis and immunohistology. Data indicated that MRA from diabetic mice have a smaller passive diameter than MRA from control mice under intra-luminal pressure range from 25 to 125 mmHg. Measurements of wall thickness : lumen diameter ratios (21 +/- 1.8 vs 14 +/- 1.2 at 75 mmHg diabetic vs control, respectively), wall thickness and remodelling index (38 +/- 5% vs control) revealed eutrophic structural remodelling of MRA from diabetic mice, which was strengthened with histology. Mechanical properties revealed a great strain-stress relationship in MRA from control versus diabetic mice indicating increased stiffness in MRA from diabetic mice. Western blot analysis showed increased collagen type 1 content in a freshly isolated MRA from the type 2 diabetic mice when compared to control mice. Diabetic mice treated with EGFR inhibitor (AG1478, 10 mg/kg/day) for 2 weeks showed reduced EGFR phosphorylation, wall thickness, collagen type 1 content, and improved the altered mechanical properties of MRA. These data provide evidence regarding the role of EGFR in morphological wall remodelling and altered mechanical properties of MRA from type 2 diabetic mice. This may identify new therapeutic targets for the control of vascular structure and therefore have important implications in type 2 diabetes.

Cardiovascular Pathology, 2011

Introduction-Previously, we demonstrated that inhibition of poly(ADP-ribose) polymerase (PARP) ex... more Introduction-Previously, we demonstrated that inhibition of poly(ADP-ribose) polymerase (PARP) exerts protective effects against high-fat (HF) diet-induced atherogenesis, in part, by increasing tissue inhibitor of metalloproteinase (TIMP)-2 expression. Given that characteristics of dilated cardiomyopathy closely associate with atherosclerosis and are mediated by an imbalance between matrix metalloproteinases (MMPs) and TIMPs, we hypothesized that PARP-1 gene deletion may protect against HF-induced cardiac hypertrophy and dilatations by altering TIMP-2/ MMPs balance in favor of a maintenance of tissue homeostasis.

British Journal of Pharmacology, 2000

1 In resistance arteries pressure-induced (myogenic) tone (MT) and¯ow (shear stress)-induced dila... more 1 In resistance arteries pressure-induced (myogenic) tone (MT) and¯ow (shear stress)-induced dilation (FD) are potent determinant of vascular resistance. We investigated the role of angiotensin II and endothelin-1 in FD and MT in resistance arteries and their potential change in hypertension. 2 Flow ± diameter ± pressure relationship was established in situ, under anaesthesia, in two daughter branches of a mesenteric resistance artery (180 mM, n=7 per group) from spontaneously hypertensive (SHR) or normotensive (WKY) rats. One artery was ligated distally, so that it was submitted to pressure only, while the other was submitted to pressure and¯ow. Drugs were added to the preparation and external diameter, pressure and¯ow measured continuously. 3 External diameter (with¯ow) ranged from 150+3 to 191+7 mM in WKY (n=28) rats and from 168+6 to 186+6 mM in SHR (n=28). Flow induced a dilation of the non-ligated arteries which was lower in SHR (13+5 ± 31+4 mM vs WKY: 5+5 ± 44+4 mM). In the ligated artery, the diameter did not signi®cantly change, due to MT. 4 In the vessels submitted to¯ow angiotensin converting enzyme inhibition (perindopril, 10 mmol L 71 ) increased the diameter in SHR (+11+2 mM) signi®cantly more than in WKY (+2+1 mM). Angiotensin type 1 receptor (AT 1 R) blockade (losartan, 10 mmol L 71 ) increased the diameter in the vessels with¯ow in SHR only (+6+1 mM). Angiotensin type 2 receptor (AT 2 R) blockade (PD 123319, 1 mmol L 71 ) decreased arterial diameter in WKY only (9+2). Endothelin-1 type A receptor (ET A R) blockade (LU135252, 0.1 mmol L 71 ) increased the diameter only in SHR in the artery submitted to¯ow (by 6+1 mM).

Pharmacology and Toxicology, 2001

Large coronary arteries undergo marked circumferential and axial deformations due to changes in b... more Large coronary arteries undergo marked circumferential and axial deformations due to changes in blood pressure and gross movements of the ventricular wall during systole and diastole. The present study was designed to investigate 1) whether axial stretch of large coronary arteries influences the sensitivity to vasoconstrictors, 2) the mechanisms mediating stretch-dependent changes in vascular sensitivity. Endothelium-denuded cylindrical segments from large porcine coronary arteries were studied under isometric conditions using a balloon-based impedance planimetric technique. In segments subjected to a pressure of 60 mmHg, 20% axial stretch caused a left-ward shift of the concentration-response curves for K π and 5-hydroxytryptamine (5-HT). Enhancement of vascular sensitivity to 5-HT induced by axial stretch was observed also in maximally K π -depolarized coronary arteries. Protein kinase C inhibition by calphostin C (1 mM) slightly decreased the spontaneous resting tone at 60 mmHg and inhibited the leftward shift of the concentration-response curve for 5-HT elicited by axial stretch. These results suggest that axial stretch of the vessel wall enhances the sensitivity of coronary arteries to vasoconstrictors by a protein kinase C-dependent mechanism.

AJP: Heart and Circulatory Physiology, 2014

27 The effects of ODQ, an inhibitor of the activation of soluble guanylate cyclase on 28 response... more 27 The effects of ODQ, an inhibitor of the activation of soluble guanylate cyclase on 28 responses to NO donors, Acetylcholine (ACh) and Bradykinin (BK) were 29 investigated in the pulmonary and systemic vascular beds of the rat. In these 30 studies the administration of ODQ in a dose of 5 mg/kg iv attenuated vasodilator 31 responses to 5 different NO donors without inhibiting responses to ACh and BK in 32 the systemic and pulmonary vascular beds of the rat. Vasodilator responses to ACh 33 were not inhibited by L-NAME or the TRPV4 antagonist GSK2193874 which 34 attenuated vasodilator responses to the TRPV4 agonist GSK1016790A. ODQ did not 35 inhibit vasodilator responses to agents reported to act in an NO independent 36 manner or to vasoconstrictor agents and ODQ did not increase blood 37 methemoglobin levels suggesting that off target effects were minimal. These results 38 show that ODQ in a dose that inhibited NO donor mediated responses did not alter 39 vasodilator responses to ACh in the pulmonary and systemic vascular beds and did 40 not alter systemic vasodilator responses to BK. The present results indicate that 41 decreases in pulmonary and systemic arterial pressures in response to ACh are not 42 mediated by the activation of soluble guanylate cyclase or TRPV4 channels and that 43 ODQ can be used to study the role of the activation of sGC in mediating vasodilator 44 responses in the rat. 45 46 47 48 49 3 50 Introduction 51

Cardiovascular Research, 1998

Flow (shear stress)-induced dilation (FD) is attenuated in hypertension. Flow triggers the releas... more Flow (shear stress)-induced dilation (FD) is attenuated in hypertension. Flow triggers the release by endothelial cells of dilators, such as NO or cyclo-oxygenase (COX) derivatives and constrictor factors such as endothelin-1 (ET-1) which might be involved in several cardiovascular diseases. We hypothesized that ET-1 might play a functional role in FD and participate in the endothelial dysfunction in hypertension. We investigated the effect of chronic treatment with the ETA receptor blocker LU135252 (50 mg/kg/day) for 2 weeks on the dilator response to flow in normotensive (Wistar-Kyoto; WKY) or hypertensive (SHR, n = 7 or 8 per group) rats. Systolic arterial pressure was not significantly affected by chronic ETA receptor blockade in both strains. In mesenteric resistance arteries (diameter: approximately 100 microns), isolated in vitro, FD was lower and myogenic tone higher in SHR than in WKY rats. Chronic ETA receptor blockade increased FD by 73% (7.5 +/- 1.5 to 13.0 +/- 2.7 microns dilation with a flow-rate of 150 microliters/min) in SHR (no effect in WKY). The participation of NO to FD was increased in SHR and the participation of dilator COX product(s) (blocked by indomethacin 10 mumol/l) to FD was significantly increased in SHR and in WKY. In control rats FD was improved by acute ETA receptor blockade in WKY rats (18.5 +/- 2.0 to 23.2 +/- 1.8 microns dilation to flow-rate of 150 microliters/min) and significantly more in SHR (6.0 +/- 1.8 to 15.1 +/- 1.6 microns). Acetylcholine-induced dilation was also improved by chronic ETA receptor blockade (no effect of an acute blockade). Myogenic and phenylephrine-induced tone were not affected by chronic or acute ETA receptor blockade. The improvement of endothelium-dependent dilation was not related to a change in blood pressure. Chronic ETA receptor blockade increased flow-induced dilation in SHR possibly by suppressing flow-induced ETA stimulation and by improving the release of dilator products by the endothelium.