维生素D代谢相关基因拷贝数变异及其DNA甲基化水平与2型糖尿病的关系研究

Many studies have supposed that vitamin D play an important role in the process of type 2 diabetes mellitus because it can promote the secretion of insulin and improve in sulinresistance. VDR, Gc and CYP2R1 are the key genes on the metabolic pathways of Vitamin D. The abnormal variants in these genes will deteriorate the function of vitamin D in vivo and increase the risk of diabetes mellitus. Therefore, based on the previous studies this project will use the case-control family study and laboratory research methods to make clear the association between the copy number variants and DNA methylation in VDR, Gc and CYP2R1 genes and the susceptibility of type 2 diabetes mellitus. The real-time fluorescent quantitative PCR and HPLC will be used to detect the copy number variants and DNA methylation in VDR, Gc and CYP2R1 genes of the subjects. Then combined the living environment, we will use a variety of statistical methods and software to comprehensively assess the causes and the roles of the environment, genetic heritage and epigenetic modification and their interaction in the process of type 2 diabetes mellitus, which will provide a scientific basis for comprehensive control of this chronic disease.

研究表明维生素D能够促进胰岛素分泌、改善胰岛素抵抗，在糖尿病的发病及血糖控制中发挥着重要作用。维生素D受体基因（VDR）、结合蛋白基因（Gc）以及细胞色素P450基因（CYP2R1）是维生素D代谢通路上的关键基因，这些基因变异将影响维生素D功能的发挥并最终导致2型糖尿病（T2DM）患病风险增加。课题组前期研究发现VDR、Gc基因的SNP多态性与T2DM的发病密切相关，鉴于基因组拷贝数变异和DNA甲基化在疾病的发展中也扮演重要的角色，本研究拟建立T2DM病例对照家系资源库，采用荧光定量PCR及高效液相色谱等技术对受试者VDR、Gc和CYP2R1基因拷贝数变异及其DNA甲基化水平进行分析测定，结合受试者的生活环境，运用多因子降维、logistic回归等统计学手段和方法综合评价环境、遗传易感性及表观遗传学修饰等在T2DM中的作用机理，以及三者之间的交互作用，为T2DM的综合防治提供科学依据。

本课题采用1:1匹配的病例对照和家系设计研究方法，探讨并验证维生素D代谢通路中CYP2R1、CYP27B1、CYP24A1、GC和VDR基因的SNP、基因拷贝数、DNA甲基化水平与2型糖尿病的关联性。研究采用Taqman荧光探针相对定量PCR及高分辨率溶解曲线法等技术对受试者的基因拷贝数变异及其DNA甲基化水平进行分析测定。结果显示，CYP2R1基因rs12794714位点、CYP24A1基因rs6068816位点、VDR基因rs2189480位点变异和2型糖尿病之间存在显著的关联性；CYP27B1基因拷贝数与2型糖尿病存在显著的关联性；GC基因甲基化水平的升高可能会增加2型糖尿病的患病风险。本研究结果为维生素D与2型糖尿病的关联性提供了新的证据，对深入了解2型糖尿病发生过程中维生素D相关的分子机制，制定维生素D缺乏症和2型糖尿病的预防策略具有重要的意义。