自噬影响线粒体DNA诱导的肺泡巨噬细胞焦亡调控重症中暑肺损伤的机制研究

The reason for severe heatstroke (sHS) with high mortality is that the progress of organ damage cannot be stopped by cooling treatment in most clinical patients. In previous study on SHS, We found that the degree of lung injury was directly related to the Mortality, However, the mechanisms is still unclear. The pyroptotic cell has been recently proven to promote inflammation by release multiple inflammation factors and cellular contents, which resulted in the aggravation of organ injury. We conducted re-experimentatal study found that mtDNA damage and proptosis can be induced in AM by sHS ,What is more, the pyroptotical AM can induce inflammation of the neighbor cell. It suggested the newly observed pyroptosis may play an important role in lung injury of sHS. Autophagy, one of the critical mechanism for the clearance of damaged mtDNA, is associated with pyroptosis. The result of our re-experimentatal study shows that autophagy can be actived in AM by sHS. But the relationship between autophagy and pyroptosis in AM of sHS is still unclear. By using gene knockout/silencing or inhibitors, the present object was performed to investigate the potential role and molecular mechanism of AM pyroptosis and the effect of autophagy on pyroptosis in lung injury induced by sHS, which might be of significance in understanding the novel insights into pathogenesis of sHS. And we intended to seek the effective methods for preventing and treating lung injury by targeting the key molecular point. Thereby futher proposing the new theory concerning the effect of autophagy on pyroptosis in sHS -induced lung injury. Finally, We hope to find a new way to cure sHS by preventing pyroptosis to alleviate lung injury and subsequently MODS, which will be great helpful for clinical treatment.

重症中暑（sHS）死亡率居高不下，近年发现sHS高病死率原因在于患者降温救治后，仍无法阻断脏器损伤继续进展。我们前期研究发现肺损伤严重程度直接影响sHS高病死率，但机制尚不明确。细胞焦亡，一种新发现的促炎性细胞死亡，可导致大量炎症因子和细胞内容物释放，级联放大炎症反应，加剧损伤。预实验发现sHS可诱导mtDNA损伤，引起AM焦亡，焦亡细胞进一步引起临近细胞炎性损伤，放大炎症反应。焦亡可能在sHS肺损伤中发挥重要作用。自噬可清除mtDNA，与焦亡关系密切。进一步预实验发现sHS可激活AM自噬，但与焦亡关系尚不明确。该课题拟采用基因敲除/沉默或抑制剂等手段，多层面探讨AM焦亡在重症中暑肺损伤中的作用及可能分子机制以及自噬对焦亡的可能影响；并寻求有效的防治靶点。从新的视角深入认识sHS肺损伤的发病机制，提出自噬影响焦亡参与sHS肺损伤的新理论；通过干预手段，探索减轻肺损伤、防治MODS的新途径。

重症中暑（sHS）死亡率居高不下，近年发现sHS高病死率原因在于患者降温救治后，仍无法阻断脏器损伤继续进展，但具体发病机制认识不清，以致缺乏有效的治疗措施。本团队前期研究发现肺损伤严重程度直接影响sHS高病死率，但机制尚不明确。课题组进一步对全国多家单位千余例中暑患者进行流调分析发现，机械通气是中暑患者死亡的高危因素。本团队进一步展开基础实验研究，发现重症中暑大鼠肺组织出现肺泡出血、肺泡上皮细胞损伤、炎症浸润等一系列病理改变，复温处理后损伤持续进展，肺损伤的严重程度直接影响其死亡率。因此探讨肺损伤在重症中暑病理机制中作用及相关机制具有重要价值。.本研究制备了重症中暑动物及细胞模型，通过体内外实验发现中暑会引起肺泡巨噬细胞焦亡，参与肺损伤的病理过程；予以清除肺泡巨噬细胞后，可改善肺损伤的严重程度。通过进一步分子机制探索，研究发现重症中暑通过诱导ROS的产生，引起线粒体及线粒体DNA损伤，激活NLRP3炎症小体，进而活化caspase-1引起细胞焦亡形成；予以ROS清除剂，或构建线粒体DNA缺失细胞，或采用NLRP3基因沉默等多种手段对此通路相关分子进行干预后，可减少焦亡细胞数目，从而减轻肺损伤程度。自噬作为细胞内的重要代谢过程，参与多种疾病的发生发展，本研究进一步探讨自噬对焦亡的影响，通过体内外实验研究发现，重症中暑可激活自噬，进而减少线粒体及其DNA损伤，降低NLRP3炎症小体激活程度及细胞焦亡水平，减轻肺损伤；予以自噬抑制剂3MA预处理，则加剧细胞焦亡及肺损伤。.本研究从多层面探讨细胞焦亡在重症中暑肺损伤中的作用及可能分子机制以及自噬对焦亡的影响。从新的视角深入认识sHS肺损伤的发病机制，提出自噬影响焦亡参与sHS肺损伤的新理论；为探索减轻肺损伤、防治MODS提供了新方向和干预靶点。.