miR-15a抑制APLN表达调控糖尿病心肌纤维化的机制研究

Diabetic cardiomyopathy is one of the most serious complications of diabetes, and one of its main features is myocardial fibrosis. Timely detection and intervention can delay the development of diabetic cardiomyopathy. Recently, it was reported that microRNA was involved in the regulation of the diabetes and its cardiovascular complications. Our previous study found that miR-15a in the cardiac fibroblasts stimulated by high glucose was significantly elevated, as well as in the left ventricular expression of C57BLKS/J db/db diabetic cardiomyopathy mouse model. Bioinformatics analysis proved that APLN might be the targeted gene of miR-15a, whlile APLN was shown to play an important role in the process of myocardial fibrosis. Meanwhile, APLN in the the left ventricular of diabetic cardiomyopathy mouse and cardiac fibroblasts stimulated by high glucose were shown decreased compared to control group respectively. Therefore, we propose our scientific hypothesis “miR-15a regulated the myocardial fibrosis in diabetic cardiomyopathy by inhibiting the APLN”. We will study the downstream signaling molecules of miR-15a in cardiac fibroblasts by gain of function and loss of function using quantitative PCR, immunoblotting techniques and so on. And we intend to find the mechanism of miR-15a regulating diabetic myocardial fibrosis using both cardiac fibroblasts and db/db diabetic cardiomyopathy mouse model. The result would provide the basis to improve the mechanism of myocardial fibrosis and to provide experimental evidence and theoretical basis to delay the progression of diabetic cardiomyopathy.

糖尿病心肌病是糖尿病最严重的并发症之一，主要特征为心肌纤维化，但其发生机制尚未明确。近年来发现多种microRNA与糖尿病及其心脏并发症相关。我们前期研究发现miR-15a在具有糖尿病心肌纤维化特征的C57BLKS/J db/db小鼠左心室中表达明显升高，经25mM高糖刺激心肌成纤维细胞后制备糖尿病心肌纤维化的细胞模型，同样发现miR-15a表达水平明显增加。生物信息学检测发现APLN可能是miR-15a的靶基因，而APLN被证实在心肌纤维化过程中具有重要保护作用，且db/db小鼠心脏及高糖刺激的心肌成纤维细胞中APLN水平均较对照组明显降低。根据预实验结果我们假设“miR-15a通过抑制APLN表达调控糖尿病心肌纤维化”，拟研究miR-15a对糖尿病心肌纤维化的调控机制及其可能的下游基因。本项目的完成将为抑制糖尿病心肌纤维化、延缓糖尿病心肌病的进展提供实验依据和新的理论基础。

本项目发现miR-15a表达水平与糖尿病心肌纤维化密切相关，提示其可能参与糖尿病心肌病的发生。在细胞水平抑制miR-15a,发现可明显改善高糖刺激诱导的心肌纤维化水平，并对Apelin的分泌及表达具有调节作用。在糖尿病心肌病小鼠模型中抑制心脏miR-15a水平，结果发现miR-15a表达下调后，血液和心脏中Apelin水平明显增加，心肌纤维化水平及大鼠心功能得到有效改善，提示miR-15a可能是通过影响心肌成纤维细胞Apelin的分泌及表达调节心肌纤维化水平。为临床延缓糖尿病心肌病的进展提供新的理论基础和治疗靶点。.本课题已发表SCI收录论文3篇，另修回1篇，培养博士1名，申请专利1项, 获得上海市医学科技奖三等奖一项。较好的完成了课题任务书规定的研究内容。