CYP2A13遗传变异与5-羟甲基-2-糠醛交互作用对2型糖尿病发生的影响及机制研究

Type 2 diabetes mellitus (T2DM) is a complex chronic disease resulting from genetic variations, environmental factors and their interactions. Our previous study showed that, 5-Hydroxymethyl-2-furfural (5-HMF) is a new toxic component extracted from cigarette smoke, could be activated by cytochrome P450 2A13 (CYP2A13), and has highly widespread exposure in the population. CYP2A13 is an extrahepatic enzyme expressed in respiratory tract and pancreas, and has a highly polymorphic. We found exposure to 5-HMF and CYP2A13 gene polymorphisms were significantly associated with risk of T2DM, respectively. In this project, we will conduct a large sample population to explore the interactions between CYP2A13 genetic variations and 5-HMF using GDMR and Logistic regression model, and to identify the important genetic variations. Furthermore, the vitro metabolic experiments, transfected cells and transgenic mice model will be established via exposure to 5-HMF using factorial design, and experimental results including the expressions of CYP2A13, 5-HMF and its metabolites, the pathology of pancreas -related and islet function will be collected to verify the conclusion in population study and clarify the mechanism of interactions. The study will provide novel insights on the mechanism underlying the 5-HMF-induced T2DM, and provide new theoretical basis on pathogenesis, risk assessment and prevention of T2DM.

2型糖尿病（T2DM）是遗传和环境及其交互作用引起的复杂疾病。5-羟甲基-2-糠醛（5-HMF）是课题组首次发现、可被CYP2A13代谢活化的新毒性组分，大量存在于含糖食品，人群暴露广泛；CYP2A13是在人胰脏和呼吸系统表达的肝外代谢酶，具有较强的基因多态性；前期研究发现5-HMF内暴露、CYP2A13 SNPs均与T2DM患病显著关联。本项目拟开展大样本人群研究，采用GMDR联合叉生分析、Logistic回归模型解析CYP2A13 SNPs与5-HMF致T2DM发生的交互作用模式和强度，筛选关键变异位点。再利用体外代谢、人胰岛细胞、CYP2A13嵌入和CYP2A5敲除小鼠，基于析因设计策略构建5-HMF染毒模型，观察CYP2A13表达和活性、5-HMF及代谢产物、胰脏病理及胰岛功能，验证人群研究结果，阐明交互作用机制。研究力图为T2DM的发病机制、风险评估及防治提供新的理论依据。

2型糖尿病（T2DM）是遗传和环境及其交互作用引起的复杂疾病。项目组从香烟烟雾中首次发现可被CYP2A13代谢活化的新毒性成分5-羟甲基-2-糠醛（5-HMF），人群暴露广泛，而CYP2A13在人胰腺中表达，具有较强的基因多态性。前期研究发现5-HMF内暴露、CYP2A13 SNPs均与T2DM患病显著关联，但因果联系和作用机制尚不明确。本项目开展了大样本的病例对照研究，运用倾向性分析和多元回归等方法，证实了人群血清5-HMF内暴露与T2DM的患病风险显著相关；对其中初发的T2DM和健康对照人群开展OGTT实验，结果提示5-HMF可能通过影响胰岛分泌功能发挥作用；采用小样本的GWAS明确了五个CY2A13 SNPs位点(rs413901, rs406133, rs420720, rs420490, rs415075)可以显著降低5-HMF的内暴露水平；CYP2A13 rs420720与5-HMF内暴露存在显著拮抗作用，可能降低T2DM的患病风险。进一步开展体外和细胞动物实验去验证人群研究的发现，阐明5-HMF与CYP2A13基因的相互作用机制。体外代谢证实，5-HMF经CYP2A13代谢为DFF/ FFDA/ FFCA，其中DFF是重要的毒性代谢产物；C57BL/6小鼠长期气雾吸入5-HMF可造成IPGTT和IRT异常，原代胰岛的GSIS和灌流实验表明胰岛分泌的第II时相显著受损。敲除该代谢基因可缓解胰岛β功能的损害，提示5-HMF与CYP2A13基因存在拮抗作用。该研究从人群流行病学、细胞和动物水平系统阐明了5-HMF经CYP2A13代谢活化致胰脏损伤和T2DM发生发展的重要作用，为T2DM的发病机制、风险评估及防治提供新的理论依据。