自体DNA/STING介导的免疫炎症反应在动脉粥样硬化中的作用机制研究

Inflammation has been closely linked to auto-immunogenic processes in atherosclerosis. However, the molecular cues underlying autoimmune activation in atherosclerosis remain elusive. As reported, the undigested DNA released from nucleus and mitochondria of dying cells could stimulate autoimmune activation, and stimulator of IFN genes (STING) could be activated by self-DNA to trigger the production of numerous cytokines including type I interferon. Interestingly, we have found that protein expression of STING was upregulated in aortas of ApoE(-/-) mice fed with high-fat diet. Comparisons of patients with asymptomatic versus symptomatic carotid artery stenosis revealed an increase in expression of STING in peripheral blood mononuclear cells. We proposed that self-DNA/STING-mediated immuno-inflammatory response might play an important role in progression of atherosclerosis. . Firstly, STING would be overexpressed by transfecting with recombinant adenovirus containing STING-overexpressing plasmid or suppressed by transfecting with STING shRNA adenovirus particles in endothelial cells, macrophages, and dendritic cells to evaluate its function in endothelial injury, macrophage differentiation into foam cells, and maturation of dendritic cells in response to oxLDL and dsDNA90 in vitro. . Secondly, we would evaluate the effects of knockout of STING gene or treatment with STING agonist in progression of atherosclerosis in ApoE(-/-) mice fed with high-fat diet. . The study will provide novel insights to understand self-DNA/STING mediated autoimmune activation in atherosclerosis.

基础和临床研究均支持动脉粥样硬化（atherosclerosis, AS）是一种自身免疫疾病这一观点。细胞坏死或凋亡后从细胞核和线粒体释放出来的自体DNA可以刺激机体的免疫应答，诱导自身免疫反应的发生。自体DNA可以激活STING依赖的信号途径，导致I型干扰素的异常增加。我们的动物和临床研究发现主动脉STING蛋白表达增加与AS的发生具有相关性。我们推测自体DNA/STING介导的免疫炎症反应可能参与了AS的发生。本课题拟研究AS发生过程中，STING在内皮细胞损伤、树突状细胞激活、巨噬细胞泡沫化过程中作用和调控机制。在细胞水平通过RNAi或过表达的方式观察STING的作用；在整体水平通过ApoE(-/-)小鼠喂食高脂饲料建立动脉粥样硬化模型，使用STING缺失小鼠和药物干预的方法观察STING的作用机制。本课题将进一步认识自身DNA/STING介导的免疫炎症反应参与AS发生发展的潜在机制

本课题目的是研究STING在动脉粥样硬化（AS）发生发展过程中的作用和角色。在小鼠水平，通过喂食高脂饲料（HFD）建立模型，发现STING缺失可以减轻HFD诱导的血脂水平升高和脂肪肝的发生。在ApoE(-/-)小鼠中使用STING激动剂DMXAA干预对HFD诱导生成的AS斑块形成没有影响。令人意外的是，DMXAA干预对ApoE(-/-)小鼠血脂水平甚至产生部分有利调节。进一步研究发现：在ApoE(-/-)小鼠中，STING缺失对AS斑块形成没有影响，对血脂水平产生不利调节，同时进一步恶化脂肪肝的发生。本课题的结果提示STING缺失对血脂异常和脂肪肝的发生具有有利调节；然而它的作用可能依赖ApoE蛋白的存在。