AngII激活的Smads/miR-26正反馈环路在高血压血管重构中的作用及机制研究

miR-26 are significant down-regulated miRNAs in Ang II-induced functional changes in vascular smooth muscle cells(VSMCs),which was discovered by us by using miRNA chip analysis. Our preliminary study found that down-regulation of miR-26 was involved in Ang II-induced proliferation and extracellular release in VSMCs. mIR-26 was significantly down-regulated in the process of hypertensive vascular remodeling (VR). Indicating that miR-26 might be a negative regulator in VR. Based on the recent progress, we hypnotized that Ang II induced Smads/miR-26 positive feed-back loop might be responsible for the down-regulation of miR-26 in VR, moreover lack of miR-26 might be the new mechanism of VR progress. In this study, we aimed to observe the regulatory effect of Ang II on Smads/miR-26 loop both in vitro and in vivo, clarify the role of miR-26 in Ang II-induced VSMCs proliferation and ECM production and possible mechanism. We will also use Lentiviral up or down-regulated miR-26 in vivo, and to further explore the role of miR-26 in VR. This project may added some theoretical basis and provide some new method for VR prevention.

miR-26是我们发现的AngII诱导血管平滑肌细胞（VSMCs）功能改变过程中显著下调的miRNA。前期研究表明，其下调具有促VSMCs增殖及细胞外基质（ECM）释放的作用，且在高血压血管重构（VR）进程中显著下调，提示其可能是高血压VR中的保护性因子。结合最新研究进展，推测Ang II激活Smads/miR-26正反馈环路是高血压VR进程中miR-26下调的重要机制，而miR-26下调在高血压VR进程中起重要作用。为证实以上假说，本研究拟以VSMCs为研究对象，进一步在细胞及整体水平观察Ang II对Smads/miR-26通路的调节作用；明确miR-26对AngII诱导VSMCs增殖及ECM释放的调控作用，探究其关键靶分子及作用通路；应用慢病毒载体在体调控miR-26表达，分析作用前后VR变化，明确其在VR进程中的重要作用。本研究的开展将为高血压VR防治提供新线索和潜在干预靶点。

MicroRNA-26a（miR-26a）参与高血压血管重塑的调节，本课题首先以Ang II诱导的小鼠、自发性高血压大鼠及miR-26a基因敲除小鼠为研究对象，同步观察高血压血管重塑进展、miR-26a表达变化情况，并应用腺相关病毒上调自发性高血压大鼠miR-26a表达，分析作用前后血管重塑的变化确定了miR-26a对高血压血管重塑具有保护性作用。进而以血管平滑肌细胞（VSMCs）为研究对象，利用qRT-PCR、Western-blot、ELISA、染色质共沉淀技术、免疫荧光联合激光共聚焦技术及流式细胞等技术，确证AngII激活的Smads/miR-26a正反馈环路在调控miR-26a表达中的重要作用，继而通过miR-26a功能缺失及过表达明确miR-26a在Ang II诱导VSMCs异常增殖及ECM释放中的重要作用；以 EZH2/p21/cyclin D2、TGFβ/CTGF及MMP2信号通路为切入点，深入探讨其在AngII诱导VSMCs增殖及释放ECM的可能机制。之后，我们又进行拓展实验，通过以心肌成纤维细胞（CFs）为研究对象的细胞学实验、以自发性高血压大鼠及miR-26a基因敲除小鼠为研究对象的动物实验结合以高血压患者为研究对象的临床实验证实miR-26a对高血压心室重塑亦具有保护性作用。本课题的研究结果助于进一步揭示高血压心血管重塑的分子机制，为高血压的综合防治提供新的靶点和策略。项目资助发表核心论文14篇，SCI论文2篇，国际会议论文4篇，待发表SCI论文4篇。培养硕士生5名，博士生1名，均获得相应学位。