VRAC活化NLRP3/Caspase-1/GSDMD焦亡信号通路在肠缺血再灌注后肠损伤中的作用及机制

肠缺血再灌注（I/R）是导致患者死亡的重要原因之一，其机制尚未明了。已证实细胞焦亡作为一种促炎性死亡方式在组织器官I/R损伤中起重要作用，而经典焦亡信号通路NLRP3/Caspase-1/GSDMD的激活依赖细胞内K+、Cl-外流。容积调控阴离子通道（VRAC）能在低渗细胞水肿时活化，导致细胞内K+、Cl-外流。申请者前期研究发现VRAC抑制剂可减轻肠I/R后肠损伤，伴随着焦亡相关蛋白表达下调，提示VRAC通过调控焦亡参与肠损伤过程。据此，申请者推测：肠I/R导致肠上皮细胞水肿，激活VARC导致细胞内K+、Cl-外流，进而活化NLRP3/Caspase-1/GSDMD信号通路，最终引起失控的炎症反应及肠粘膜上皮细胞焦亡导致肠损伤。本项目将通过一系列体内外实验来验证该假说，为寻找防治肠I/R损伤可供干预的靶点提供理论依据。

Intestinal ischemia-reperfusion (I/R) is one of the most important causes of death, but its pathogenesis remains unclear. In recent years, researches have confirmed that pyroptosis is playing an important role in I/R injury, and NLRP3/Caspase-1/GSDMD is the canonical signaling pathway of pyroptosis. Potassium and chloride efflux has been proposed to have an essential function in NLRP3 inflammasome activation. Volume regulated anion channels (VRAC) can be activated in extracellular osmolarity during cell swelling, resulting in potassium and chloride efflux. We recently found that VRAC inhibitor can reduce intestinal injury after intestinal I/R, with the down-regulation of pyroptosis related protein expression. Our data identified that VRAC as a basic conserved homeostatic mechanism is associated with pyroptosis and intestinal I/R. Based on the above findings, we hypothesize that intestinal epithelial cells swelling after intestinal I/R could active of VRAC, which lead to NLRP3/Caspase-1/GSDMD signaling pathway activation. Therefore, the present study aims to verify this hypothesis via a series of in vivo and in vitro experiments. This study will provide scientific basis for seeking for therapeutic targets which can be intervened in prevention of intestinal I/R injury.