组蛋白转甲基酶G9a调节巨噬细胞炎症反应在双酚A暴露促进动脉粥样硬化中的作用及机制研究

Bisphenol A (BPA) exposure is an independent risk factor for cardiovascular disease, promotes the development of atherosclerosis (AS) which is associated with the inflammatory response enhancement in macrophages. Histone methyltransferase G9a mediated histone H3K9 methylation regulates the inflammatory response in macrophages, but whether it is involved in the BPA accelerated AS is still unclear. Through the use of methods including conditional knock-out, monocyte tracking and so on, we evaluate the effects of BPA on H3K9 methylation, inflammatory signals and factors, monocyte recruitment in AS plaques, sizes and compositions of AS plaques in G9a wild-type or knock-out mice, in vitro studies are designed to determine the signaling pathways involved in the regulation of G9a in BPA enhanced inflammatory response in macrophages through detection of the expressions of inflammatory factors following NLRP3 or NFκB inhibition or gene silencing, chromatin immunoprecipitation (ChIP) analysis is used to investigated the H3K9 methylation levels in the promoter of inflammatory genes. Through this study, we will illuminate the roles and mechanisms of histone methyltransferase G9a regulated inflammatory response in macrophages during bisphenol A accelerated atherosclerosis, so as to provide a new theoretical basis and therapeutic targets for prevention of BPA related cardiovascular diseases.

双酚A（BPA）暴露是心血管疾病的独立危险因素，促进动脉粥样硬化（AS）进展并与巨噬细胞炎症反应放大相关，我们前期研究发现组蛋白转甲基酶G9a介导的组蛋白H3K9甲基化调节BPA引起的巨噬细胞炎症反应，但在BPA促进AS进展中的作用尚不清楚。本项目拟运用条件性基因敲除、单核细胞示踪等手段，在整体动物层面观察巨噬细胞G9a缺失对BPA暴露引起的H3K9甲基化水平、炎症信号分子和炎性因子表达、单核细胞斑块内聚集、斑块病损程度及成分变化的影响，在离体细胞层面通过沉默或抑制NLRP3和NFκB，观察炎性因子表达变化，明确G9a参与BPA促进巨噬细胞炎症反应的信号途径，采用染色质免疫共沉淀技术分析H3K9甲基化与炎性基因的结合位点及特征。通过研究，以期阐明G9a介导的H3K9甲基化在BPA促进巨噬细胞炎症反应及AS过程中的作用及机制，为防治BPA的心血管危害提供新的理论依据和干预靶点。

双酚A（BPA）暴露增加心血管疾病发生风险，促进动脉粥样硬化（AS）进展并与巨噬细胞炎症反应放大相关，但相关机制尚不清楚。本项目通过建立AS动物模型、RNA干扰、免疫荧光等技术手段，在整体动物和离体细胞两个层面进行系列研究。首次发现了CCAAT增强子结合蛋白C/EBPβ是巨噬细胞p65/NF-κB和Caspase-1的上游调控分子。一方面，C/EBPβ调控p65/NF-κB，进而调节IL-1β表达；另一方面，C/EBPβ调控Caspase-1参与IL-1β剪切成熟；率先揭示了组蛋白去乙酰化酶Sirtuin 1通过调控DNA修复关键蛋白NBS1表达，介导DNA损伤修复，在BPA 加重巨噬细胞炎症和动脉粥样硬化中发挥了关键作用；基本明确了Sirtuin 1激动剂白藜芦醇对BPA促进动脉粥样硬化发生发展的防治作用；初步发现了组蛋白转甲基酶G9a心脏特异缺失导致心脏纤维化及其关键蛋白和代谢通路。研究成果为进一步理解炎症调控机制提供新的见解，为防治BPA相关心血管危害提供新的理论依据和干预靶点。项目发表SCI论著3篇，其中影响因子大于5分的论著2篇。