H3K9me2在砷致DNA损伤修复中的调控机制及银杏制剂干预研究

Currently, it is a bottleneck problem that the pathogenesis and carcinogenic mechanisms of endemic arsenic poisoning is unclear, and no special treatment drugs, which limit the prevention and control of endemic arsenic poisoning. Endemic arsenic poisoning is also a major public health issue that governments and scholars are highly concerned about. It has been reported that arsenic exposure can promote the development of arsenic poisoning by inhibiting the expression of DNA repair genes, but the mechanism is not clear. Recent studies have shown that H3K9me2 may play an important role in arsenic-induced DNA damage repair. In this study, based on the previous study of our research group, from research in population to the cellular level, enzyme-linked immunosorbent assay (ELISA), real-time quantitative PCR (qRT-PCR), Western Blotting, quantitative chromatin immunoprecipitation and other techniques were used. At the same time, histone methylase inhibitors, siRNA, high expression plasmids and ginkgo preparations were used to deal the subjects of different system. The aim of this study is to systematically explore the regulation mechanism of H3K9me2 in arsenic-induced DNA damage repair from both forward and reverse angles, and to provide new ideas and scientific basis for the pertinence prevention and targeted therapy of endemic arsenic poisoning.

地方性砷中毒致病致癌机制不明，至今无特效治疗药物是限制其防治的瓶颈问题，也是各国政府和学者高度关注的重大公共卫生问题。砷暴露通过抑制DNA损伤修复基因的表达，促进砷中毒的发生发展，但机制尚不明确。新近研究表明，组蛋白H3K9me2可能在砷致DNA损伤修复过程中扮演着重要角色。本项目在课题组前期研究的基础上，从人群和细胞两个实验体系，采用酶联免疫吸附实验（ELISA）、实时荧光定量PCR（qRT-PCR）、免疫印迹(Western Blotting)、定量染色质免疫沉淀（ChIP-qPCR）等技术，同时采用组蛋白甲基化酶抑制剂、siRNA、高表达质粒和银杏制剂等处理不同体系研究对象，从正向和反向较深入系统地探讨H3K9me2在砷致DNA损伤修复中的调控机制，为地砷病的针对性预防和靶向治疗提供新思路和科学依据。

地方性砷中毒致病和致癌机制不明，至今缺乏特效的治疗药物，一直是限制其防治的瓶颈问题，因此其是各国政府和学者高度关注的重大公共卫生问题，也是我国的重大防治疾病。课题组前期研究发现，砷暴露可通过抑制DNA合成和修复基因的表达，抑制DNA的损伤修复，从而促进砷中毒的发生发展；砷中毒患者外周血淋巴细胞组蛋白H3K9me2总体修饰水平与DNA损伤程度呈负相关关系，表明H3K9me2可能在砷致DNA损伤过程中扮演着重要角色。本研究立足我国和我省重点地方病防治需求，利用贵州省特有的燃煤型砷中毒病型资源，从整体（人群）和体外（细胞）两个实验体系，系统深入研究了H3K9me2在砷致DNA损伤修复中的调控机制，并利用贵州特产银杏制剂进行干预研究，为地砷病的针对性预防和靶向治疗提供新思路和科学依据。. 研究发现，砷通过G9a上调HaCaT细胞MPG、XRCC1、PARP1基因启动子区H3K9me2的富集水平，抑制MPG、XRCC1、PARP1基因的表达，影响细胞DNA损伤修复功能，加重DNA损伤程度；砷通过JHDM2A调控L-02细胞H3K9me2总体修饰水平，改变DDB2、MPG、XRCC1、PARP1的表达，影响DNA损伤程度，但不通过JHDM2A调控DDB2、MPG、XRCC1、PARP1启动子区（CHIP1、CHIP2）的H3K9me2修饰水平，改变DNA损伤修复基因的表达而影响DNA损伤程度；银杏制剂可通过G9a逆转H3K9me2的修饰水平，从而促进DNA修复基因转录表达，拮抗砷致HaCaT细胞及砷中毒患者DNA的损伤程度，本研究为地砷病的机制研究和靶向治疗提供了新思路和科学依据，对控制砷中毒危害具有重要实际应用价值。