胚胎干细胞（ESCs）是具有自我更新及多向分化潜能的一类细胞群，可在体外诱导为血管平滑肌细胞（VSMCs），但其定向分化机制尚未阐明。课题组前期实验发现miR-22在小鼠ESCs向VSMCs分化过程中起关键作用。本项目拟：1）构建稳定表达miR-22前体或反义核苷酸分子的小鼠ES细胞株，深入探索miR-22促ESCs定向分化VSMCs的分子机制；2）构建含miR-22可能靶基因Mecp2、MYCBP和MYST4的3’UTR质粒，进行报告基因检测，同时观察miR-22介导的生物学效应是否会由于靶基因的上调/下调而改变，探讨miR-22—靶基因功能网络的作用关系；3）建立小鼠股动脉导丝损伤模型，在体水平验证miR-22对其靶基因的调控作用，并验证miR-34a是否在血管损伤新生内膜形成中起保护作用。本研究有助于加深对VSMCs分化机制的认识，同时为今后有效地防治血管疾病提供新的潜在药物靶点。

Smooth muscle cell (SMC) differentiation is a critical process during cardiovascular development, and SMC proliferative related cardiovascular disease, such as atherosclerosis, postangioplasty restenosis and transplantation arteriopathy. Therefore, better understanding of the molecular mechanisms of vascular SMC differentiation is essential for improving the treatment or prevention of cardiovascular disorders. microRNAs (miRNAs) have been recently suggested to play important roles not only in the regulation of multiple biological cellular functions, but also in the cardiovascular diseases. By applying our well-establish SMC differentiation model, we have recently found that miR-22 is significantly up-regulated during SMC differentiation from mouse embryonic stem (ES) cells. Data from our miR-22 gain-of-function and lose-of-function studies clearly demonstrated that miR-22 plays a crucial role in SMC differentiation, and that miR-22 mediated SMC differentiation through modulation of SMC transcription factor such as myocardin. In this proposal, we will further investigate the crucial role of miR-22 in SMC differentiation from mouse ES cells, and elucidate its molecular mechanism. We will also investigate the functions of miR-22 in vessel injury-induced neointima formation and the underlying mechanisms. Results of the study would help to better understand the biological mechanisms underlying SMC differentiation and injury-induced neointima formation, and could provide a new strategy for therapeutic intervention in atherosclerosis and postangioplasty restenosis.