新型线粒体自噬受体NLRX1调节巨噬细胞焦亡在Midkine促动脉粥样硬化中的作用

中期因子（MK）是促动脉粥样硬化（As）的心血管事件独立预测因子，作用机制未明。巨噬细胞焦亡是促进动脉粥样硬化病变进展的重要因素，预实验发现，MK可影响巨噬细胞焦亡，但机制不详。有研究发现，线粒体自噬可调控细胞焦亡，而模式识别受体NLRX1是新型线粒体自噬受体。生物信息学分析结合预实验，我们发现，MK可下调巨噬细胞线粒体NLRX1表达，并抑制线粒体自噬，腺苷酸活化蛋白激酶（AMPK）可能参与了调控。因此，我们认为“MK可能抑制巨噬细胞AMPK磷酸化，调控NLRX1而抑制线粒体自噬，促进巨噬细胞细胞焦亡，从而加速As进程”。本项目拟以巨噬细胞及As小鼠模型为研究对象，采用转染、荧光探针、电镜和激光共聚焦及常规分子生物学技术，验证MK对巨噬细胞线粒体自噬和细胞焦亡的影响，阐明AMPK/NLRX1在其中的作用以及对MK促As作用的影响机制，为开发As防治靶点提供新策略和实验依据。

Midkine (MK), an independent predictor of cardiovascular, promote atherosclerosis (AS), and the mechanism of which is unclear. Meanwhile, macrophage pyrolysis play a decisive role in atherosclerotic lesion progression. We found that MK could inhibit macrophage pyrolysis in our preliminary study, however, the underlying mechanism is still ambiguous. Studies have found that mitochondrial autophagy can promote cell pyrolysis. The pattern recognition receptor NLRX1 is a new mitochondrial autophagy receptor. We further found that MK could downregulate the expression of NLRX1 in macrophage mitochondria, and inhibit mitochordrial autophagy by adenylate-activated protein kinase (AMPK). Therefore, we consider that MK may inhibit the phosphorylation of AMPK, inhibit mitochondrial autophagy by regulating NLRX1, promote macrophage pyrolysis, and thus exacerbate AS. In this project, it is to verify that the MK could affect mitochondrial autophagy and macrophage pyrolysis, aggravate AS by AMPK/NLRX1 in macrophages and AS mouse models using transfection, fluorescent probes, electron microscopy, laser confocal and conventional molecular biology techniques analysis, which provides potential preventive and therapeutic targets for medical intervention of AS patients in the future.