表观遗传调控因子SIRT3基因表达失调与心肌梗死 的分子遗传学研究

Coronary artery disease (CAD) is a common disease and myocardial infarction (MI) is a specific type of CAD. Though a great number of genetic loci associated with CAD has been identified with genome-wide association studies, genetic causes and underlying molecular mechanisms remain largely unclear. Recently, it has been reported that dysregulated gene expression has been widely associated with human diseases. SIRT3 is a members of surtuin family, a group of deacetylases. SIRT3 epigenetically regulate gene expression and play important roles in lipid metabolism, inflammation, as well as cardiac protection. We postulate that the DNA sequence variants in the regulatory regions of SIRT3 gene may change its gene expression level, leading to CAD development. In this study, we employ case-control and candidate gene strategy, investigate the association of dysregulated SIRT3 gene with MI. At first, SIRT3 gene regulatory region is directly sequenced and compared between MI patients and healthy controls to identify the DSVs associated with MI. Then, the biological functions of the DSVs are analyzed in cultured cells and in experimental animals. Furthermore, molecular mechanisms by which the DSVs change the gene expression levels are explored. Finally, mouse models carrying the DSVs are established by knock-in strategy. The molecular mechanisms by which DSVs lead to MI will be investigated and elucidated. Our study may provide a solid theoretical and experimental basis for prevention and efficient treatment for MI patients.

冠状动脉性心脏病( CAD)是一常见多发性疾病，心肌梗死（MI）为其严重类型。尽管全基因组扫描等发现一系列CAD相关的遗传位点，但其致病基因和分子机制尚不清楚。遗传变异导致基因表达失调与人类疾病的相关性已有报道。SIRT3属于Surtuin去乙酰化酶家族，通过表观调控基因表达，参与脂质代谢和炎症反应，具有保护心脏的作用。因此，我们提出假设，认为SIRT3基因调控区域的DNA序列变异（DSVs），改变其基因表达水平，通过上述不同途径，导致CAD的发病。因此，我们拟采用病例-对照和候选基因策略，探讨SIRT3基因表达失调与MI的相关性。首先对其SIRT3基因调控区域进行测序、发现与MI相关的DSVs；然后在体外和体内分析其生物学活性；进而探讨DSVs引起基因表达水平改变的分子机制；最后应用基因敲入的方法建立MI小鼠动物模型，探讨导致MI的分子机制，为有效治疗MI提供可靠的理论基础和实验依据。

冠状动脉性心脏病(CAD)是一常见多发性疾病，急性心肌梗死（AMI）为其严重类型。迄今为止，CAD和AMI致病基因和分子机制尚不清楚。SIRT3属于Surtuin去乙酰化酶家族，通过表观调控基因表达，参与脂质代谢和炎症反应，具有保护心血管系统的作用。我们认为SIRT3基因表达异常与CAD和AMI的发病相关。在本项目中，我们应用AMI病人临床样本，采用分子遗传学和分子生物学手段，分析线粒体SIRT3/4/5基因调控区域的遗传变异与AMI的相关性，并探讨其作用分子机制。研究结果发现，在AMI病人中SIRT3/4/5基因启动子调控区域存在一系列遗传变异位点，包括DNA序列变异（DSVs）和单核苷酸多态性（SNPs）。在体外培养细胞中，这些变异位点显著改变SIRT3/4/5基因启动子的转录活性。分子机制研究表明，这些变异位点通过影响SIRT3/4/5基因启动子区域与转录因子的结合发挥作用。因此，SIRT3/4/5基因启动子调控区域的变异位点通过改变转录因子的结合，影响其转录活性，进而导致SIRT3/4/5的水平改变。通过表观调控其下游的基因，参与AMI的发病。我们的研究结果将为发现AMI的精准分子靶点提供基础和依据，具有重要的转化研究和临床应用价值。