间质流剪切力调控血管平滑肌细胞表型转化的力学生物学机制研究

The phenotypic switching of smooth muscle cells (SMCs), which plays a key role in atherosclerosis, is regulated by interstitial flow shear stress (IFSS). Our previous work demonstrated that Yes-associated protein (YAP) expressed highly in human atherosclerotic lesions. However, the role of YAP in SMCs phenotypic switching induced by IFSS remains unclear. By using microfluidic system and transwell co-culture system, we supposed to simulate the progress of SMCs affecting by IFSS in atherosclerotic lesions. Combined the shear stress loading system with the cellular biology and molecular biology techniques, we will illustrate the role of YAP in IFSS-induced phenotypic switching of SMCs. Furthermore, to determine the mechanobiological mechanisms regulating YAP in SMCs phenotypic switching induced by IFSS, we will explore the expression and distribution alteration of crucial genes and proteins in Hippo-MST1/2-LATS1/2 signal pathway. The findings of this project can provide new insight for revealing the mechanisms of atherosclerosis development and find potential drug targets.

血管平滑肌细胞（SMCs）表型转化受间质流剪切力调控，在动脉粥样硬化进程中起重要作用。申请人前期工作发现：力学敏感蛋白Yes-associated protein（YAP）在人动脉粥样硬化组织中呈现高表达。然而，YAP是否参与间质流剪切力调控SMCs的表型转化尚未明确。本项目采用微流控系统、transwell共培养系统，模拟粥样硬化段血管组织微环境中间质流剪切力对SMCs的作用，结合细胞生物学、分子生物学等技术手段探索YAP在间质流剪切力诱导SMCs表型转化中的作用。在此基础上，通过解析Hippo-MST1/2-LATS1/2信号通路上关键分子的基因和蛋白表达的时序性变化，明确YAP参与间质流剪切力诱导SMCs表型转化的力学生物学分子机制。研究结果有望为探明动脉粥样硬化发展机制提供新思路，为动脉粥样硬化防治提供新的药物靶点。

在项目执行过程中，项目负责人严格按照研究计划开展工作。本项目构建了多种体外力学加载模型，对血管平滑肌细胞施加间质流剪切力，模拟动脉粥样硬化段血管中平滑肌细胞所受力学刺激。研究结果表明，升高的间质流剪切力可以调控平滑肌细胞的表型转化，诱导平滑肌细胞从收缩型向合成型转变，上调平滑肌细胞的迁移能力，从而促进动脉粥样硬化的发展。进一步，项目负责人证实了力学敏感蛋白YAP(Yes-associated protein)在间质流剪切力调控平滑肌细胞表型转化中的重要作用。YAP蛋白受力学刺激后，其表达水平显著上调，磷酸化水平显著下调。YAP蛋白进入细胞核，发挥其转录因子的功能，启动平滑肌细胞合成型标志物的转录程序。最后，项目负责人解析了Hippo信号通路上关键因子（MST1,LATS1）受力学刺激后的时序性变化及其对YAP蛋白转录活性的调控作用。综上所述，本项目初步探明了间质流剪切力调控平滑肌细胞表型转化的力学生物学分子机制，为进一步了解动脉粥样硬化发展的力学生物学分子机制提供了新思路，有望为动脉粥样硬化治疗提供潜在的药物靶点。