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

描述(申请人提供)：适度饮酒(酒精)是动脉粥样硬化及其临床后遗症心肌梗死、缺血性中风和外周血管疾病的负面风险因素。人们对乙醇可能诱导其假定的心脏保护作用的确切细胞信号和分子机制知之甚少。我们先前已经报道，虽然乙醇刺激内皮细胞(EC)的生长和迁移，但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具有协同的心脏保护作用，因此具有相当大的临床意义。此外，我们的初步数据显示，每天适度的酒精喂养显著抑制小鼠颈动脉结扎损伤后的内膜中层增厚。EC和SMC表达Notch受体，包括我们在内的几个小组已经描述了Notch信号在成年EC和SMC分化、增殖和凋亡调节中的关键作用。在实验诱导的血管损伤后，Notch通路的几个组成部分，包括受体和下游靶基因Hes和HRT的表达发生了变化。我们的数据还表明，Etoh对EC和SMC的Notch信号通路有不同的作用，分别是刺激和抑制，并进一步表明这一途径既介导了Etoh促进EC增殖，也抑制了SMC增殖。跨膜蛋白Nogo-B由EC和SMC表达，在完整的血管中表达，最近被确定为血管重塑的调节因子，限制了损伤后血管损伤的进展。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，可能反映了两种细胞之间受体表达的差异。我们的初步数据表明，乙醇调节血管细胞中Nogo-B的表达。尽管Notch和Nogo在血管重塑调节中都有作用，并且在EC和SMC中的表型调节作用各不相同，但到目前为止还没有研究发现Nogo和Notch的相互作用，更不用说作为酒精的靶标了。我们的中心假设是，乙醇刺激EC，抑制SMC的生长，从而通过Nogo-B介导的Notch依赖的方式抑制血管重构。我们将使用体外培养的人冠状动脉内皮细胞和SMC来验证这一假设，并结合体内研究，利用小鼠血管损伤和重塑的颈动脉结扎‘血流限制’模型。由于EC和SMC生长的改变在血管疾病的发病机制中起着重要的作用，乙醇以Nogo-B依赖的方式调节这些过程是乙醇心脏保护作用的一个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，破译一种物质可以预防它的机制显然具有重大的临床重要性和意义。好了！

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. !