Role of Nogo-B in Mediating the Vascular Effects of Alcohol

描述（由申请人提供）：适量饮酒（乙醇）是动脉粥样硬化及其临床后遗症心肌梗死、缺血性卒中和外周血管疾病的负风险因素。关于乙醇可能引起其推定的心脏保护作用的精确细胞信号传导和分子机制知之甚少。我们以前曾报道，虽然乙醇刺激内皮细胞（EC）的生长和迁移，它抑制血管平滑肌细胞（SMC）的生长和迁移。鉴于EC和SMC在动脉粥样硬化的病理生理学中的关键作用，EtOH对这些血管细胞的相反作用可能预期是协同的心脏保护作用，因此具有相当大的临床意义。此外，我们的初步数据表明，每天适量的酒精喂养显着抑制内膜中层增厚后，小鼠颈动脉结扎损伤。EC和SMC表达Notch受体，包括我们在内的几个研究小组已经描述了Notch信号在调节成人EC和SMC分化、增殖和凋亡中的关键作用。Notch通路的几个组分的表达，包括受体和下游靶基因hes和hrt，在实验诱导的血管损伤后改变。我们的数据还表明，EtOH对Notch信号传导在EC和SMC，刺激和抑制，分别有不同的效果，并进一步暗示这一途径在介导EtOH的促进EC增殖和它的衰减SMC增殖。跨膜蛋白Nogo-B由EC和SMC以及在完整血管中表达，最近已被鉴定为血管重塑的调节剂，限制损伤后血管病变的进展。有趣的是，据报道Nogo-B对血管细胞具有相反的作用，促进EC的迁移，但抑制SMC的迁移，这可能反映了两种细胞类型之间受体表达的差异。我们的初步数据表明，EtOH调节血管细胞中Nogo-B的表达。尽管Notch和Nogo在血管重塑调节中的作用，以及各自在EC和SMC中关于表型调节的差异效应，但迄今为止还没有研究调查Nogo和Notch的相互作用，更不用说作为酒精的靶点。我们的中心假设是，乙醇刺激EC，并抑制SMC的生长，从而抑制Notch依赖的方式，通过Nogo-B介导的血管重塑。我们将使用体外培养的人冠状动脉EC和SMC结合利用小鼠颈动脉结扎血管损伤和重塑的“流量限制”模型的体内研究来验证这一假设。由于EC和SMC生长的变化在血管疾病的发病机制中起着突出的作用，乙醇以Nogo-B依赖的方式调节这些过程代表了乙醇心脏保护作用的一种新的和潜在的重要机制。由于心血管疾病的死亡率如此之高，因此破译一种物质可以保护其免受其害的机制显然具有重大的临床重要性和意义。!

DESCRIPTION (provided by applicant): Moderate consumption of alcohol (ethanol) is a negative risk factor for atherosclerosis and its clinical sequelae myocardial infarction, ischemic stroke and peripheral vascular disease. Little is known about the precise cell signaling and molecular mechanisms whereby ethanol may elicit its putative cardioprotective effects. We have previously reported that while EtOH stimulates the growth and migration of endothelial cels (EC), it inhibits vascular smooth muscle cell (SMC) growth and migration. Given the key role of both EC and SMC in the pathophysiology of atherosclerosis, the opposing effects of EtOH on these vascular cells might be expected to be synergistically cardioprotective and thus are of considerable clinical interest. Moreover, our preliminary data show that daily moderate alcohol feeding markedly inhibits intima-media thickening following carotid ligation injury in the mouse. EC and SMC express Notch receptors and several groups, including ours, have described a critical role for Notch signaling in the regulation of adult EC and SMC differentiation, proliferation and apoptosis. The expression of several components of the Notch pathway, including receptors and downstream target genes hes and hrt, are altered after experimentally induced vascular injury. Our data also demonstrate a differential effect of EtOH on Notch signaling in EC and SMC, - stimulatory and inhibitory, respectively, and further, implicate this pathway in mediating both EtOH's promotion of EC proliferation and it's attenuation of SMC proliferation. The transmembrane protein Nogo-B, expressed by both EC and SMC and in intact vessels, has recently been identified as a regulator of vascular remodeling, limiting the progression of vascular lesions after injury. Of interest, Nogo-B reportedly has opposing effects on vascular cells, promoting the migration of EC, but inhibiting the migration of SMC, possibly reflecting differences in receptor expression between the two cell types. Our preliminary data show that EtOH modulates Nogo-B expression in vascular cells. Despite a role for both Notch and Nogo in vascular remodeling regulation, and a differential effect of each in EC and SMC with respect to phenotype regulation, no studies to date have investigated an interaction of Nogo and Notch, much less as targets for alcohol. Our central hypothesis is that ethanol stimulates EC, and inhibits SMC growth and thus inhibits vascular remodeling in a Notch-dependent manner, mediated via Nogo-B. We will test this hypothesis using cultured human coronary artery EC and SMC in vitro in conjunction with in vivo studies utilizing the carotid ligation 'flow-restriction' model of vascular injury and remodeling in the mouse. Since changes in EC and SMC growth plays a prominent role in the pathogenesis of vascular disease, modulation of these processes by ethanol in a Nogo-B-dependent fashion represents a novel and potentially important mechanism underlying ethanol's cardioprotective effect. Because the mortality from cardiovascular disease is so high, deciphering a mechanism whereby a substance can protect against it is clearly of major clinical importance and significance. !