Nox4介导线粒体自噬对柯萨奇B3病毒性心肌炎的作用机制

Coxsackievirus B3-induced myocarditis is a cardiovascular disease that has a serious impact on the health of adolescents. The pathogenesis of the disease has not been elucidated. It has been researched that reactive oxygen species (ROS) is one of the important factors involved in the myocardial injury, and Nox4 is an important source of the generation of ROS.Studies have shown that Nox4-mediated ROS generation involved in the regulation of a variety of cardiovascular diseases, but it has not been reported whether or not Nox4 participate in the pathogenesis of viral myocarditis. Preliminary studies have showed that myocardial tissue has a significantly higher Nox4 expression, while it was being injured by CVB3. And CVB3 can induce the mitophagy of the myocardium, so we suggest that “Coxsackievirus B induced Nox4 activation of cardiomyocyte , produce large amounts of ROS, and cause mitophagy and damages of myocardium”. To confirm this hypothesis, observed the Nox4 expression and the relevance of ROS release and mitophagy , clarify the damage of myocardium caused by Nox4-mediated mitophagy , and to elaborated a new mechanism for the Coxsackievirus B-induced myocarditis. We will establish a model about mouse with Coxsackievirus B3-induced myocarditis, and use the method of confocal, immunofluorescence and western blot.

柯萨奇B3组病毒（CVB3）引起的病毒性心肌炎是一种严重影响人类健康的心血管疾病，其发病机制尚未阐明。活性氧（ROS）是参与心肌细胞损伤的重要因素之一，而Nox4是产生ROS 的重要来源。大量研究证实Nox4介导ROS生成参与调节多种心血管疾病，但对Nox4是否参与CVB3诱导心肌炎发病机制尚未见报道。本课题组前期研究显示CVB3诱导心肌损伤的同时，心肌组织中Nox4表达明显升高，且CVB3可诱导线粒体自噬，因此推测“柯萨奇B组病毒通过诱导心肌细胞Nox4活化，产生大量ROS，引起线粒体自噬及心肌细胞损伤”。为证实该假说，本课题拟采用CVB3诱导心肌细胞损伤的小鼠及细胞模型，利用激光共聚焦、免疫荧光、western blot等方法，观察心肌细胞Nox4表达、ROS释放与线粒体自噬的关系，阐明Nox4介导线粒体自噬对心肌细胞的损伤作用，为柯萨奇B组病毒诱导病毒性心肌炎阐述新机制。

柯萨奇B3组病毒（CVB3）引起的病毒性心肌炎是一种严重影响人类健康的心血管疾病 ，其发病机制尚未阐明。活性氧（ROS）是参与心肌细胞损伤的重要因素之一，Nox4作为NADPH氧化酶的同源物是产生ROS 的重要来源，Nox4是否参与CVB3诱导病毒性心肌炎发病机制尚未见报道。本课题采用CVB3诱导病毒性心肌炎体内/体外模型，观察CVB3诱导病毒性心肌炎过程中Nox4蛋白的表达、ROS释放、线粒体融合分裂、线粒体自噬及其相关通路的表达。结果表明：CVB3诱导病毒性心肌炎过程中，心肌细胞Nox4蛋白呈现高表达，ROS大量释放引起氧化应激后心肌损伤，Nox4抑制剂可减轻CVB3诱导的心肌损伤；此外还证明了Nox4与线粒体自噬及线粒体融合分裂的关系，阐明Nox4可以通过激活线粒体自噬及线粒体分裂促进CVB3诱导的心肌损伤，而PINK1-parkin通路参与心肌炎早期的自噬途径，为柯萨奇B组病毒诱导病毒性心肌炎阐述了新机制。另外，在研究中我们还发现CVB3诱导病毒性心肌炎过程中，Nox4的亚型Nox4b亦存在高表达的情况，为后续Nox4的亚型研究提供依据。在CVB3介导的病毒性心肌炎模型中，中性粒细胞外网状陷阱（NETs）生成，中性粒细胞表面受体Mac-1的激活可使p38 MAPK蛋白表达下降，参与炎症机制，这可能为病毒性心肌炎的进一步研究提供了新的思路。