环境雌激素对DNA羟甲基化的干扰效应与分子作用新机制研究

Environmental estrogens have the estrogenic activity and therefore stimulate or interfere with estrogen action. They seriously threaten the health of organisms and humans, and their pathogenesis is one of the key issues in environmental toxicology and medical research. DNA hydroxymethylation (5hmC), a recently found DNA modification via oxidation of 5-methylcytosine (5mC) catalyzed by Tet proteins, plays important roles in the embryo development, brain function, cancer occurrence and so on. Our preliminary results show that environmental estrogens can change the level of DNA hydroxymethylation, however, the pertinent biological consequences and mechanisms are largely not known. In this project, using human breast cancer cell lines MCF-7 combined with the CRISPR/Cas9 knockdown technique and genome-wide sequencing analysis, aims to study the toxic effect and regulation mechanism of environmental estrogens on the DNA hydroxymethylation modification, investigate the roles of DNA hydroxymethylation in the toxicological effects of environmental estrogens, and provide the experimental evidence and new mechanistic insights for toxicological and health impacts of environmental estrogens.

环境雌激素是具有类似生物体内雌激素活性，进入人体后可产生具有模拟或者干扰雌激素作用的环境毒素，它们严重威胁生物体和人体的健康，其致病机理的探索已成为环境毒理学和医学研究共同关心的关键问题之一。DNA羟甲基化，即5-羟甲基胞嘧啶，是由Tet酶介导的、催化氧化DNA 5-甲基胞嘧啶而形成，在胚胎发育、大脑功能以及癌症发生等方面发挥重要作用。我们初步的研究表明，环境雌激素可改变DNA羟甲基化，但是尚不清楚它们如何影响或改变DNA甲基化-Tet酶-DNA羟甲基化作用轴以及后果如何。本项目旨在利用正常人体乳腺细胞系和多种乳腺癌细胞系，结合CRISPR/Cas9敲除技术和全基因组甲基化、羟甲基化测序分析，研究环境雌激素对DNA羟甲基化水平和分布的影响及调控机制，分析DNA羟甲基化在环境雌激素毒害效应中的功能和作用，进而探索基于DNA羟甲基化调控的环境雌激素干扰新机制。