AMPK/BECN1介导的铁死亡在PM2.5诱导上皮细胞损伤中的作用及机制研究

细颗粒物（PM2.5）诱导的气道上皮细胞损伤和死亡是引起慢阻肺急性加重的主要非感染因素，目前缺乏有效的治疗方法。铁死亡是一种由铁离子依赖的脂质过氧化损伤引起的程序性细胞死亡形式。我们前期研究发现，PM2.5能够诱导铁过载和脂质过氧化，铁死亡抑制剂能减轻PM2.5诱导的细胞死亡和小鼠的气道损伤；PM2.5能激活自噬和AMPK并抑制xCT表达，但不影响GPX4的表达；与自噬抑制剂相比，AMPK抑制剂更为显著地抑制PM2.5诱导的细胞死亡和GSH耗竭。因此我们提出“PM2.5通过AMPK诱导上皮细胞铁死亡从而致气道损伤”的科学假说。本课题拟研究PM2.5对AMPK/BECN1和铁死亡的诱导作用及其关系；进一步拟建立PM2.5诱导的上皮细胞和小鼠急性气道损伤模型，采用过表达和siRNA沉默细胞或AMPK敲除小鼠，阐明PM2.5诱导气道上皮损伤的效应靶点和相关机制，为其防治提供新思路。

Airway epithelial cell injury and dysfunction resulted from fine particulate matter (PM2.5) are the main non-infectious factors that cause the acute exacerbation of COPD, so far there is no effective treatment. Ferroptosis is a form of regulated cell death mediated by phospholipid peroxidation in association with free iron-mediated Fenton reactions. Our preliminary research has shown that labile iron accumulation and enhanced lipid peroxidation with concomitant non-apoptotic cell death during PM2.5 exposure. Treatment with deferoxamine and ferrostatin-1 illuminate the role of ferroptosis in PM2.5-treated lung epithelial cells and airway injury. The levels of autophagy‐related protein and 5′‐adenosine monophosphate-activated protein kinase (AMPK) were significantly increased by PM2.5. Meanwhile, uptake of particles decreases the expression of xCT, but does not affect the GPX4 protein expression. Compared with the autophagy inhibitor 3MA, the AMPK inhibitor has more significantly inhibitory effect on PM2.5-induced epithelial cell ferroptosis and GSH depletion. Therefore, we speculate that PM2.5 may activate AMP-activated protein kinase (AMPK)-mediated ferroptosis in epithelial cells, then cause airway damage. The project is intended to firstly investigate whether PM2.5 can induce AMP-activated protein kinase (AMPK)-mediated phosphorylation of BECN1 and ferroptosis, as well as the relationship between them. Furthermore, we intend to establish PM2.5 induced primary epithelial cell and mouse models of airway damage, and applied AMPKα RNA interference and AMPKα knockout mice to determine the target and mechanisms. The present study will provide new ideas for the prevention and treatment of PM2.5-induced airway epithelial injury.