ECM AND CELL CYCLE CONTROL IN AORTIC SMOOTH MUSCLE CELLS

血管平滑肌细胞（VSMCs）的表型调节， 收缩性（非增殖性）到合成性（增殖性） 表型被认为在动脉粥样硬化形成中起重要作用。 尽管人们对可溶性生长的作用给予了很大的关注， 诱导平滑肌细胞增殖的因素，最近 很明显，合成的VSMC的特征是， 动脉粥样硬化病变还具有异常的细胞外基质（ECM）， 并经历表面整合素表达的变化。基于我们 先前的研究显示ECM和 有丝分裂原在调节细胞周期蛋白依赖性激酶（cdks），我们 假设ECM和整合素的变化与 合成SMC可能在控制 动脉粥样硬化中这些细胞的增殖。我们还假设 正常主动脉中VSMC的细胞周期进程被阻断， 生长抑制因子（PGI 2、NO和TGF-β 1）的释放 内皮细胞，这些因子的释放减少， 湍流位点在表型中起着重要作用 调节局部VSMCs从收缩型到合成型 收缩到合成表型。这个项目测试这些假设 在体内和体外，有四个特定的目标。在目标1中，我们将分离 动脉粥样硬化倾向小鼠（LDLREdit敲除小鼠）的主动脉， 对（i）粘附分子，（ii）酶进行原位分析 涉及DinNo合成和PGI 2合成和作用，以及（iii）细胞周期蛋白 A.将特别注意对之前发生的变化， 在病变发展的早期阶段。在目标2和3中，我们将使用 从正常小鼠的早期传代VSMC培养物中确定 细胞粘附和不同的ECM蛋白及其整合素 调节PI期细胞周期蛋白和cdk抑制剂。在目标4中，我们 确定内皮细胞生长抑制剂 影响生长因子和/或ECM依赖性细胞周期进程 血管平滑肌细胞。总的来说，这些研究的结果将确定 ECM作为控制VSMC增殖的细胞调节元件， 确定内皮细胞局部释放的变化- 衍生的抑制剂可以解释VSMC的离散性 动脉粥样硬化的增殖和病变发展。

The phenotypic modulation of vascular smooth muscle cells (VSMCs) from the contractile (non-proliferating) to synthetic (proliferating) phenotype is thought to play an important role in atherogenesis. Although much attention has been given to the role of soluble growth factors in inducing smooth muscle cell proliferation, it has recently become clear that the synthetic VSMCs characteristic of the atherosclerotic lesions also have an abnormal extracellular matrix (ECM) and undergo changes in the expression of surface integrins. Based on our previous studies showing important cooperative effects of the ECM and mitogens in regulation of the cyclin-dependent kinases (cdks), we hypothesize that the changes in the ECM and integrins associated with synthetic SMCs may have an important role in controlling the proliferation of these cells in atherosclerosis. We also hypothesize that cell cycle progression of VSMCs is blocked in the normal aorta by release of growth inhibitory factors (PGI2, NO, and TGF-beta1) from endothelial cells, and that the decreased release of these factors at sites of turbulent flow plays an important role in the phenotypic modulation of local VSMCs from the contractile to synthetic from contractile to synthetic phenotype. This project tests these hypotheses in vivo and in vitro with four specific aims. In aim 1, we will isolate aorta from atherosclerosis-prone mice (the LDLREdit knock-out mouse) and perform in situ analyses for (i) adhesion molecules, (ii) enzymes involve din No synthesis and PGI2 synthesis and action, and (iii) cyclin A. Particular attention will be pair to changes occurring prior to and in the early stages of lesions development. In aims 2 and 3, we will use early passage VSMC cultures from normal mice to determine the degree to which cell adhesion, and distinct ECM proteins and their integrins regulate the PI phase cyclins and cdk inhibitors. In aim 4, we will determine the mechanism by which endothelial cell growth inhibitors influence growth factor and/or ECM dependent cell cycle progression of VSMCs. Overall, results from these studies will define the role of the ECM as a cell regulatory element controlling VSMC proliferation and determine whether changes in the local release of endothelial cell- derived inhibitors can account for the discrete nature of VSMC proliferation and lesion development in atherosclerosis.