Alcohol Regulation of Resident Vascular Stem Cells.

 描述（由申请方提供）：血管平滑肌细胞（vSMC）在心血管疾病（CVD）的病理生理学中发挥关键作用。新出现的证据表明，存在于血管壁内的干细胞分化为vSMC，并且是动脉壁重塑和修复的积极贡献者。这些信息突出了一个新的细胞靶点，以研究已知影响CVD的药物，以及治疗血管疾病的新的潜在治疗靶点。虽然酒精（EtOH）消耗是影响CVD发病率和严重程度的一个公认因素，但其对常驻血管干细胞再生能力的影响尚未确定。涉及血管疾病进展的干细胞群包括位于中膜外膜边界的Sca 1+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。有几种因子被描述为干细胞自我更新、分化和生长的调节因子，最值得注意的是形态原音刺猬（Shh）。我们已经表明，与APC群体共定位的α-肌动蛋白阴性、Hh阳性细胞位于正常血管的中膜-外膜边界处，并且随后在损伤后出现在α-肌动蛋白阳性中膜和内膜层内。Hedgehog信号通过分泌的Shh配体与跨膜受体Patched（Ptch）的结合而触发，并且随后由属于Gli家族的转录效应子介导。Hedgehog途径的组分在体内血管损伤后被诱导，并且Hedgehog-Notch信号传导轴控制体外vSMC生长和表型。最重要的是，我们最近发现，在血管壁内原位抑制hedgehog信号传导可减弱损伤后的内膜-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，酒精干扰了常驻血管干细胞的更新和/或分化，从而通过影响hedgehog信号传导影响血管重塑和CVD。我们将在体外（APC）和体内（颈动脉结扎小鼠动脉粥样硬化模型）测试这一假设的有效性，并研究酒精可能调节Hedgehog信号传导的机制，重点是Ptch 1受体-Caveolin-1在脂筏中的共定位和E3泛素连接酶的降解。解读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.