MIR-182调控急性心肌梗死后心肌细胞凋亡的作用和机制研究

Myocardial Apoptosis is an important factor of cardiac dysfunction aftermyocardial infarction. We previously found that bone marrow mesenchymal stem cells(MSCs) could inhibit cardiomyocyte apoptosis, but the mechanism is unclear. Preexperimental results were showed that miR-182 contained Exosome could be absorbed by myocardial cell. MiR-182 overexpression can inhibit cardiomyocyte apoptosis. Our Bioinformatics analysis showed that E2F2 was a target gene ofmiR-182. Recent studies have showed that E2F2-mediated phosphorylation of p53 can induce apoptosis through up-regulation of Gadd45β. We therefore hypothesize thatmiR-182 can regulate E2F2-p53-Gaddd45β pathway and inhibit cardiomyocyte apoptosis too. using mouse Primary cardiomyocyte hypoxia/reoxygenation model andmyocardial infarction model.We will investigate the effect of miR-182 oncardiomyocyte apoptosis and the role of E2F2 expression regulation.In E2F2 gene knockout and overexpressded mouse model, We will elucidate the effect andmechanism of miR-182 in the E2F2-p53-Gaddd45β pathway at the level of cells and animals. This study was expected to explore new targets and provide new theoretical for the treatment of acute myocardial infarction.

心肌细胞凋亡是造成心肌梗死后心功能减退的重要因素。研究显示，骨髓间充质干细胞（MSCs）具有抑制心肌细胞凋亡的作用，但机制不明。预实验结果提示，miR-182过表达抑制心肌细胞凋亡。生物信息学分析发现E2F2是miR-182的靶基因。新近研究证实，E2F2能介导p53磷酸化而上调Gadd45β，诱导细胞凋亡。由此提出假说：MSCs分泌的miR-182通过调控E2F2及E2F2-p53-Gaddd45β通路，抑制心肌细胞凋亡，改善心功能。本课题拟利用原代心肌细胞缺氧/复氧模型及小鼠心梗模型，探讨miR-182对心肌细胞凋亡及E2F2表达调控的作用，验证miR-182是MSCs抑制细胞凋亡的重要因子；采用E2F2基因敲除和转基因小鼠，在细胞和动物水平上，阐明miR-182对E2F2-p53-Gadd45β信号通路的调控作用及分子机制。本课题有望为急性心肌梗死探索新的靶点。

急性心肌梗死是危害人类健康的重要疾病。心肌梗死后心肌细胞的凋亡是心肌细胞死亡的重要病理过程，如何减少心肌梗死后心肌细胞凋亡是急性心肌梗死治疗面临的一个瓶颈。MicroRNA是一组不编码蛋白质的短序列RNA,具备多种生物学功能,新近研究发现,miR-182-5p能改善心脏功能。本研究前期实验证实，miR-182-5p可以改善心肌细胞凋亡，但可能的机制并不十分清楚。另外，E2F2基因通过上调p53蛋白表达，并激活磷酸化P53，进而诱导细胞凋亡。而E2F2可能是miR-182-5p的靶分子。本研究通过构建大鼠及小鼠心肌梗死模型，并使用腺相关病毒AAV9转染小鼠后，发现miR-182-5p可以减少心肌梗死面积、改善心肌功能，可能的机制为通过降低E2F2、P53等的表达，进而改善心肌细胞凋亡来实现。本次实验的发现，为寻找心肌修复效果的新靶点及干预方法以及为急性心肌梗死的治疗奠定理论和实验基础。