Alcohol Regulation of Resident Vascular Stem Cells.

 描述(申请人提供)：血管平滑肌细胞(VSMC)在心血管疾病(CVD)的病理生理学中起着关键作用。新的证据表明，存在于血管壁中的干细胞向vSMC分化，是动脉壁重塑和修复的积极贡献者。这一信息突出了一个新的细胞靶点，用于研究已知影响心血管疾病的药物，以及治疗血管疾病的新的潜在治疗靶点。虽然酒精摄入是影响心血管疾病发生率和严重程度的一个公认的因素，但它对常驻血管干细胞再生能力的影响尚未确定。与血管疾病进展有关的干细胞群包括位于内侧外膜边界的Sca1+外膜祖细胞(APC)。在血管损伤模型中，APC增殖并分化为侵袭内膜的vSMC。有几个因素被描述为干细胞自我更新、分化和生长的调节因素，最著名的是形态发生因子声波刺猬(Shh)。我们已经证明，与APC群体共定位的α-肌动蛋白阴性的HH阳性细胞位于正常血管的内膜-外膜边界，然后在损伤后出现在α-肌动蛋白阳性的中膜和内膜层内。Hedgehog信号是由分泌的Shh配体与跨膜受体补丁(PTCH)结合而触发的，随后由Gli家族的转录效应分子介导。Hedgehog途径的组成部分在体内血管损伤后被诱导，Hedgehog-Notch信号轴在体外控制vSMC的生长和表型。最重要的是，我们最近的研究表明，在血管壁上原位抑制Hedgehog信号可以减轻损伤后的内膜-中膜增厚。我们的初步数据表明，酒精调节vSMC中Hedgehog信号成分的表达，Shh在体外控制干细胞向vSMC的转化。因此，我们的总体假设是酒精通过影响Hedgehog信号来干扰驻留的血管干细胞的更新和/或分化，从而影响血管重塑和心血管疾病。我们将在体外和体内(Caroti结扎小鼠动脉粥样硬化模型)测试这一假说的有效性，并探讨酒精可能调节Hedgehog信号的机制(S)，重点是PTCH1受体-小窝蛋白-1在脂筏中的共定位和E3泛素连接酶的降解。破译酒精影响心血管疾病的机制具有重要的临床意义。

 DESCRIPTION (provided by applicant): Vascular smooth muscle cells (vSMC) play a key role in the pathophysiology of cardiovascular disease (CVD). Emerging evidence suggests that stem cells present within the vessel wall differentiate to vSMC and are the active contributors to the remodeling and repair of the artery wall. This information highlights a new cell target to investigate for agents known to affect CVD, as well as a novel potential therapeutic target for treatment of vascular disease. While alcohol (EtOH) consumption is a well-established factor affecting the incidence and severity of CVD, its effects on the regenerative capacity of resident vascular stem cells have yet to be ascertained. A stem cell population implicated in vascular disease progression includes Sca1+ adventitial progenitor cells (APC) that reside at the medial adventitial boundary. APC proliferate and differentiate into vSMC that invade the intima in vascular injury models. Several factors have been described as regulators of stem cell self-renewal, differentiation and growth, most notably the morphogen sonic hedgehog (Shh). We have shown that a-actin negative, Hh-positive cells that co- localize with the APC population are located at the medial-adventitial boundary of normal vessels and later appear within the a-actin positive medial and intimal layer following injury. Hedgehog signaling is triggered by binding of the secreted Shh ligand with the transmembrane receptor Patched (Ptch) and is subsequently mediated by transcriptional effectors belonging to the Gli family. Components of the Hedgehog pathway are induced after vascular injury in vivo and a Hedgehog - Notch signaling axis controls vSMC growth and phenotype in vitro. Crucially, we have recently shown that local inhibition of hedgehog signaling in situ within the vessel wall attenuates intimal-medial thickening following injury. Our preliminary data now indicate that alcohol regulates the expression of hedgehog signaling components in vSMC, and that Shh controls stem cell transition to vSMC in vitro. Therefore, our overall hypothesis is that alcohol interferes with the renewal and/or differentiatio of resident vascular stem cells, and thus affects vessel remodeling and CVD, by affecting hedgehog signaling. We will test the validity of this hypothesis in vitro (APC) and in vivo (caroti ligation mouse model of atherosclerosis) and investigate the mechanism(s) whereby alcohol may modulate Hedgehog signaling, focusing on Ptch1 receptor-Caveolin-1 co-localization in lipid rafts and degradation by E3 ubiquitin ligases. Deciphering the mechanisms whereby alcohol affects cardiovascular disease is of major clinical importance and significance.