miR-21通过TGF-β/Smads对糖尿病心肌纤维化发病机制的影响及干预研究

Diabetic cardiomyopathy (DCM) is a kind of specific myocardial disease caused by diabetes，which its mechanism has not been fully elucidated. MiR-21 and TGF-β1 was closely associated with fibrosis. Our preliminary experiments showed that miR-21 overexpression decreased smad7 and increased smad3 expression. Conversely, inhibition of miR-21 increased smad7 and decreased smad3 expression. Moreover，ACEI significantly downregulated miR-21 expression in cardiac fibroblasts and myocardial tissues. Hereby, we speculated that ACEI repressed myocardial fibrosis by inhibiting miR-21 expression and further upregulating smad7 expression. In this study, myocardial fibrosis was as a center-link of DCM, miR-21 and TGF-β1 was as a breakthrough point in fibrosis network, and ACEI was as the main intervention measures. In situ hybridization, real-time RT-PCR, cell transfection, luciferase reporter gene assays, western blot and confocal microscope were used, respectively. This study will further elucidate new mechanism of ACEI anti-fibrosis, and whether miR-21 was one of new targets with ACEI. Expected results of the research will greatly expand the pathogenesis of DCM and provide new theoretical basis for development of new anti-fibrosis drug as miRNAs targets in the future.

糖尿病心肌病(DCM)是糖尿病导致的一种特异的心肌疾病，其机制尚未完全阐明。miR-21 和TGF-β1与纤维化密切相关。我们前期研究发现：miR-21过表达能显著下调Smad7，上调Smad3表达；抑制miR-21表达则上调Smad7，下调Smad3表达；ACEI能够下调心肌成纤维细胞和心肌组织miR-21表达。故推测ACEI通过下调miR-21表达，上调smad7表达，起抗心肌纤维化作用。因此，本课题针对DCM发病中心环节——心肌纤维化，以miR-21和TGF-β1/Smads为切入点，以ACEI为干预措施，采用原位杂交、RT-PCR、WB，细胞转染、荧光素酶报告基因检测及激光共聚焦等技术，进一步阐明miR-21能否成为ACEI新的作用靶点，并在体内观察以miR-21为靶点的抗纤维化效应。预期成果将极大拓展DCM发病机制，为将来研发以miRNA为靶点的新型抗纤维化药物提供新的理论依据。

糖尿病心肌病(Diabetic cardiomyopahty, DCM)是糖尿病患者致死的主要原因之一。miR-21和TGF-β/Smads与纤维化密切相关，miR-21是否通过TGF-β/Smads途径参与DCM的发病机制及ARB对miR-21诱导的纤维化的影响仍旧不清。本研究针对DCM发病的中心环节—细胞外基质（ECM）过度沉积，以ECM基因调控网络中的关键成分miR-21和TGF-β1/Smads为切入点，以保护心脏的药物缬沙坦为干预措施。采用原位杂交、RT-PCR、WB，细胞转染、荧光素酶报告基因及激光共聚焦等技术；结果发现，（1）miR-21参与糖尿病心肌病的发病机制，（2）miR-21与TGF-β1/Smads信号途径形成正反馈的调节作用，（3）miR-21能够成为ARB治疗DCM的作用靶点之一。该研究成果将为糖尿病心肌纤维化发生发展机制提供线索，并为抗纤维化药物的开发提供新的方向。