miR-133a基因多态性与糖尿病心肌病的关联关系及分子机制

Diabetic cardiomyopathy is an important fatal cause of diabetes mellitus. It is an urgent problem to find genetic precursory markers clinically. We performed microarray profile analysis of microRNAs in the high glucose-cultured cells and the parental cells respectively. Our results demonstrated that miR-133a expressed much lower in the high glucose-cultured cells than the parental cells. MiR-133a polymorphisms were preliminarily assessed in a screening population of 50 controls and 50 subjects with diabetic cardiomyopathy. We found that rs8089787 and rs13040413 of miR-133a correlated with the risk of diabetic cardiomyopathy. This study intends to evaluate the relationship of miR-133a polymorphisms with diabetic cardiomyopathy in a larger population of 300 controls and 300 subjects with diabetic cardiomyopathy. Serum miR-133a expression is examined in order to illustrate the association between miR-133a polymorphisms and miR-133a expression. In order to clarify the related molecular mechanisms, we transfect different carrier plasmids into cell lines in vitro. The interactions of miR-133a polymorphisms and MEF2A are evaluated. The biological effects of miR-133a polymorphisms are also evaluated by assessing the expression of apoptosis-related factors, such as Bcl-2, Bax, Caspase-9, and so on. The results of our study will play an important role in identifying vulnerable populations of diabetic cardiomyopathy, as well as provide a theoretical basis for personalized medication.

糖尿病心肌病是糖尿病患者致死的重要因素，寻找其遗传预警标志物是临床迫切需要解决的难题。通过miRNA芯片，我们发现高糖培养的心肌细胞中miR-133a低表达。初筛50对糖尿病心肌病—正常对照者的miR-133a多态性，发现rs8089787和rs13040413与糖尿病心肌病的发生显著相关。本研究通过进一步检测300对糖尿病心肌病—正常对照者的miR-133a多态性，明确miR-133a多态性与糖尿病心肌病的关联关系；检测miR-133a在糖尿病心肌病—正常对照者血清中的表达，明确miR-133a多态性对其基因表达的影响；通过体外实验转染不同miR-133a多态性质粒，检测不同miR-133a多态性与预测靶基因MEF2A的相互作用及其生物学效应（凋亡相关因子Bcl-2、Bax、Caspase-9等的表达）。本研究结果期望为糖尿病心肌病易感人群提供早期遗传预警标志物并进一步指导个性化治疗。

糖尿病心肌病（Diabetic cardiomyopathy，DCM）患者更易于发生心力衰竭，约半数的糖尿病患者死于心肌病变。寻找DCM的遗传预警标志物，为其提供个体化治疗，是目前临床研究的热点及迫切需求解决的难题。本项目通过临床研究-体外验证的策略，首先在临床上寻找与DCM相关的miR-133a多态位点，然后在体外细胞系中验证miR-133a多态位点的作用机制及生物学效应。本项目研究结果表明miR-133a-2 rs13040413多态性与DCM的发病风险相关，突变型可以增加DCM的发生。体外实验发现miR-133a-2 rs13040413突变组miRNA-133a mRNA相对表达量低于野生组。相比野生组，miR-133a-2 rs13040413突变组荧光素酶相对表达量无明显变化。还发现与野生组相比，miR-133a-2 rs13040413突变组Bax的mRNA及蛋白表达量显著升高，Bcl-2的mRNA及蛋白表达量显著降低。加入MEF2A抑制剂后，Bax的mRNA及蛋白表达量减低，Bcl-2的mRNA及蛋白表达量升高。因此，我们得到结论，mi-133a-2 rs13040413突变型可以减少mi-133a的表达，进而可能减小对靶基因MEF2A的抑制作用，使其表达上调，导致与凋亡相关的细胞因子（Bax和Bcl-2），导致糖尿病患者左室舒张功能减低，糖尿病心肌病发生。本研究提示miR-133a rs13040413多态性不但可以作为糖尿病心肌病发病风险的早期遗传预警标志物，并可以作为潜在治疗靶点，为糖尿病心肌病患者提供个性化治疗。研究结果已发表论文9篇，其中SCI收录论文6篇（总IF值19.956）。