BackgroundObesity is associated with increased risks for development of cardiovascular diseases. Epidemiological studies report an inverse association between dietary flavonoid consumption and mortality from cardiovascular diseases. We studied the potential beneficial effects of dietary supplementation of red wine polyphenol extract, Provinols™, on obesity-associated alterations with respect to metabolic disturbances and cardiovascular functions in Zucker fatty (ZF) rats.Methodology/Principal FindingsZF rats or their lean littermates received normal diet or supplemented with Provinols™ for 8 weeks. Provinols™ improved glucose metabolism by reducing plasma glucose and fructosamine in ZF rats. Moreover, it reduced circulating triglycerides and total cholesterol as well as LDL-cholesterol in ZF rats. Echocardiography measurements demonstrated that Provinols™ improved cardiac performance as evidenced by an increase in left ventricular fractional shortening and cardiac output associated with decreased peripheral arterial resistances in ZF rats. Regarding vascular function, Provinols™ corrected endothelial dysfunction in aortas from ZF rats by improving endothelium-dependent relaxation in response to acetylcholine (Ach). Provinols™ enhanced NO bioavailability resulting from increased nitric oxide (NO) production through enhanced endothelial NO-synthase (eNOS) activity and reduced superoxide anion release via decreased expression of NADPH oxidase membrane sub-unit, Nox-1. In small mesenteric arteries, although Provinols™ did not affect the endothelium-dependent response to Ach; it enhanced the endothelial-derived hyperpolarizing factor component of the response.Conclusions/SignificanceUse of red wine polyphenols may be a potential mechanism for prevention of cardiovascular and metabolic alterations associated with obesity.

In this report, the expression and function of the platelet collagen receptor glycoprotein VI (GPVI) were studied in human megakaryocytes during differentiation and maturation of mobilized blood and cord blood derived CD34 ؉ cells. By flow cytometry, using an anti-GPVI monoclonal antibody or convulxin, a GPVI-specific ligand, GPVI was detected only on CD41؉ cells including some CD41 ؉ /CD34؉ cells, suggesting expression at a stage of differentiation similar to CD41. These results were confirmed at the mRNA level using reverse transcriptionpolymerase chain reaction. GPVI expression was low during megakaryocytic differentiation but increased in the more mature megakaryocytes (CD41 high ). As in platelets, megakaryocyte GPVI associates with the Fc receptor ␥ chain (FcR␥). The FcR ␥ chain was detected at the RNA and protein level at all stages of megakaryocyte maturation preceding the expression of GPVI. The other collagen receptor, ␣ 2 ␤ 1 integrin (CD49b/CD29), had a pattern of expression similar to GPVI. Megakaryocytic GPVI was recognized as a 55-kDa protein by immunoblotting and ligand blotting, and thus it presented a slightly lower apparent molecular mass than platelet GPVI (58 kDa). Megakaryocytes began to adhere to immobilized convulxin via GPVI after only 8 -10 days of culture, at a time when megakaryocytes were maturing. At this stage of maturation, they also adhered to immobilized collagen by ␣ 2 ␤ 1 integrin-dependent and -independent mechanisms. Convulxin induced a very similar pattern of protein tyrosine phosphorylation in megakaryocytes and platelets including Syk, FcR␥, and PLC ␥2 . Our results showed that GPVI is expressed early during megakaryocytic differentiation but functionally allows megakaryocyte adherence to collagen only at late stages of differentiation when its expression increases.At sites of vascular injury, platelets adhere and are activated by contact with collagen fibers exposed with the subendothelium matrix leading to thrombus formation. Several collagen receptors are present on platelets: integrin ␣ 2 ␤ 1 (CD49b/ CD29), GPIV 1 (CD36), GPVI, p65, and a recently cloned type III collagen receptor (1, 2). The direct interaction between collagen and integrin ␣ 2 ␤ 1 adheres platelets at the collagen surface, but platelet activation and thrombus formation and attachment are subsequently mainly supported by GPVI. In addition to collagen, two GPVI-specific ligands have been described: collagen-related peptides (3) and convulxin, a snake venom protein (4). GPVI has recently been characterized as a new member of the immunoglobulin superfamily of cell-associated receptors, in which expression is restricted to the hematopoietic lineage (5-7). It is coexpressed as a noncovalent complex with the common immunoglobulin receptor ␥ (FcR␥) chain, which acts as the signaling subunit of the complex (8, 9) As a consequence, signaling pathways coupled to GPVI dimerization are identical to those coupled to other immune receptors; tyrosine phosphorylation of the FcR ␥ chain on its immunoreceptor tyrosine-...

During sepsis, endothelial barrier dysfunction contributes to cardiovascular failure, mainly through the release of oxidative metabolites by penetrant leukocytes. We reported the non-muscular isoform of myosin light chain kinase (nmMLCK) playing a pivotal role in endotoxin shock injury associated with oxidative and nitrative stresses, and vascular hyporeactivity. The present study was aimed at understanding the molecular mechanism of lipopolysaccharide (LPS)-induced vascular alterations as well as studying a probable functional association of nmMLCK with nuclear factor κ-light-chain enhancer of activated B cells (NF-κB). Aortic rings from mice were exposed in vitro to LPS and, then, vascular reactivity was measured. Human aortic endothelial cells (HAoECs) were incubated with LPS, and interaction of nmMLCK with NF-κB was analysed. We provide evidence that nmMLCK deletion prevents vascular hyporeactivity induced by in vitro LPS treatment but not endothelial dysfunction in the aorta. Deletion of nmMLCK inhibits LPS-induced NF-κB activation and increases nitric oxide (NO) release via induction of inducible NO synthase (iNOS) within the vascular wall. Also, removal of endothelium prevented both NF-κB and iNOS expression in aortic rings. Among the proinflammatory factors released by LPS-treated endothelial cells, interleukin-6 accounts for the induction of iNOS on smooth muscle cells in response to LPS. Of particular interest is the demonstration that, in HAoECs, LPS-induced NF-κB activation occurs via increased MLCK activity sensitive to the MLCK inhibitor, ML-7, and physical interactions between nmMLCK and NF-κB. We report for the first time on NF-κB as a novel partner of nmMLCK within endothelial cells. The present study demonstrates a pivotal role of nmMLCK in vascular inflammatory pathologies.