miR-31在心梗后心肌纤维化中的作用及机制

Myocardial fibrosis after myocardial infarction (MF) is an important prognostic factor in patients with myocardial infarction. Phenotypic transition of cardiac fibroblasts to myofibroblasts mediated by TGF-β1/Smad3 is the cellular basis of myocardial fibrosis after myocardial infarction. However, direct inventions of TGF-β1 or Smad3 will lead to autoimmune diseases. Therefore, we intend to find the intervention targets downstream of Smad3. In our previous study, We found that in the process of myocardial fibrosis after myocardial infarction, miR-31 may be regulated by Smad3; combined with previous findings that downregulation of miR-31 inhibited myocardial fibrosis after myocardial infarction, we hypothesized that TGF-β1/Smad3 plays an important role in myocardial fibrosis after myocardial infarction by modulating miR-31. We intend to use Smad3 KO mice, CHIP assay to elucidate that miR-31 was regulated by Smad3; to clarify the role of miR-31 during myocardial fibrosis process after myocardial infarction in vivo and in vitro and confirm the functional target of miR-31 in vitro; to ascertain whether modulating miR-31 has the effect of alleviating already established myocardial fibrosis after myocardial infarction. In this project, we find the miR-31 from the downstream of Smad3, define its role in vivo and in vitro, and elucidate the molecular mechanism of miR-31 from its upstream and downstream. We will provide a new target of myocardial fibrosis after myocardial infarction for drug research and development.

心梗后心肌纤维化（MF）是影响心梗病人预后的重要原因。TGF-β1/Smad3 介导的心脏成纤维细胞向肌成纤维细胞表型转变是MF的细胞学基础，但直接针对TGF-β1或Smad3干预会引起自身免疫性疾病。因此，我们拟在Smad3下游寻找干预靶点。前期我们发现在MF过程中miR-31可能是受Smad3调控的miRNA；结合申请者之前的发现，即下调miR-31能减轻MF，我们假设TGF-β1/Smad3通过miR-31对MF具有重要作用。我们拟应用Smad3 KO小鼠、CHIP实验等明确Smad3对miR-31的调控作用；在动物和细胞水平明确miR-31在MF中的作用，并确定其功能靶基因；最后在体实验明确调控miR-31对已经形成的MF是否具有治疗效应。本项目从Smad3下游发现miR-31，从整体及细胞水平上明确其作用，从分子水平阐明其上下游机制，可为MF药物研发提供新靶点。

心梗后心肌纤维化(MF)是影响心梗病人预后的重要原因。TGF-β1/Smad3 介导的心脏成纤维细胞向肌成纤维细胞表型转变是MF的细胞学基础，但直接针对TGF-β1或Smad3干预会引起自身免疫性疾病。因此，我们拟在Smad3下游寻找干预靶点。我们研究发现在MF过程中miR-31、miR-574-5p、E2F1可能是受Smad3调控的miRNA及转录因子，通过下调miR-31、miR-574-5p、E2F1均能减轻MF。机制上我们发现，miR-31通过特异性结合CREG的3‘UTR区抑制其翻译过程、miR-574-5p通过特异性结合ARID3A的3‘UTR区抑制其翻译过程、E2F1通过与CCNE2相互作用促进其表达，从而抑制纤维化进程。进一步研究发现甲基阿魏酸（MFA）通过调控pRB-E2F1-CCNE2及RhoA-ROCK2通路提高心功能减少梗死面积，提高生存率。以上研究发现将为研制最佳的靶向治疗药物提供理论依据。