甲基正壬酮通过线粒体自噬途径防治PM2.5所致肾脏炎症损伤的机制研究

In recent years, kidney injury caused by PM2.5 has attracted wide attention, and it is presumed to be associated with the inflammatory reaction. 2-undecanone, a phytochemical, is the main component of the volatile oil of Houttuynia cordata, and has a strong anti-inflammatory effect. We have found that 2-undecanone can prevent the renal inflammatory injury induced by PM2.5, and maybe associated with mitophagy. It is supposesd that 2-undecanone activates the mitophagy pathway by up-regulating target protein Sirt3. Mitophagy inhibits inflammation by decreasing ROS level, inhibiting inflammasome activation, degrading inflammasome and reducing proinflammatory cytokines secretion. The report gene and ChIP methods are used to investigate the regulation of Sirt3 expression. The luciferase detection system was used to verify the target gene, and to explicit the molecular mechanism of Sirt3 in regulation of mitophagy. We use gene clone and RNA interference technique to investigate the relationship between mitophagy and inflammation, and observe the change of key indicators of mitophagy and inflammasome. The elucidation of this mechanism will provide new ideas for exploring the protective effect of 2-undecanone on PM2.5 induced renal inflammatory injury.

近年来，PM2.5引起的肾脏损伤引起广泛关注，推测与其诱发炎症反应有关。植物化学物甲基正壬酮是鱼腥草挥发油中的主要成分，具有较强的抗炎作用。申请人前期发现甲基正壬酮可防治PM2.5所致的肾脏炎性损伤，推测与其引起的线粒体自噬有关：甲基正壬酮通过上调靶蛋白Sirt3激活线粒体自噬途径，线粒体自噬通过降低ROS水平抑制炎症小体的激活，降解炎症小体、降低促炎因子的分泌从而抑制炎症的发生。本研究应用报告基因和ChIP等方法探讨甲基正壬酮调节Sirt3表达的作用机制，应用双荧光报告基因检测系统验证靶基因，明确Sirt3调控线粒体自噬的分子机制，利用基因克隆和RNA干扰技术从正向和反向探索线粒体自噬与炎症的关系，观察线粒体自噬和炎症小体关键指标的改变，梳理并明确线粒体自噬抑制炎症损伤的分子机制，为探寻甲基正壬酮对PM2.5所致肾脏炎性损伤的保护作用提供新思路。

当前，我国城市空气污染情况非常严峻，空气雾霾问题尤为突出，PM2.5的防治工作已经成为关注的热点。其中PM2.5引起的肾脏损伤引起广泛关注，推测与其诱发炎症反应有关。植物化学物甲基正壬酮是鱼腥草挥发油中的主要成分，具有较强的抗炎作用，本课题研究了甲基正壬酮对PM2.5引起的肾脏炎性损伤的保护作用及其机制。我们建立了甲基正壬酮保护PM2.5致肾脏炎症损伤的体内体外模型，检测炎症小体及炎症因子标志物的基因和蛋白表达。检测转录因子、靶基因表达水平的改变，明确甲基正壬酮对转录因子-靶基因信号通路的作用。应用RNAi技术及自噬抑制剂/激活剂、靶基因特异性抑制剂，观察线粒体自噬和炎症小体关键指标的改变，梳理并明确线粒体自噬抑制炎症损伤的分子机制。结果表明：甲基正壬酮通过早期促自噬因子启动自噬-溶酶体途径，完成一般性自噬的诱导；同时进行线粒体的特异性识别，通过Pink1-Parkin信号途径实现线粒体自噬。线粒体自噬通过降低ROS水平抑制炎症小体的激活，降解炎症小体、降低促炎因子的分泌从而抑制炎症的发生。本研究结果为深入研究PM2.5导致肾脏损伤的发病机制及探寻有效的抗炎物质提供新思路，为其临床应用提供理论依据。