P2X7R-NLRP3/Cav-3信号通路在心肌梗死后心室颤动发生的作用和分子机制

心室颤动(室颤)是心肌梗死后心脏性猝死最常见原因，但是促室颤电和结构重构形成的上游调控机制并不清楚。申请者前期研究发现离子通道型嘌呤受体-7（P2X7R)与小窝蛋白-3（Cav-3）在心室肌细胞共定位，Cav-3起锚定离子通道蛋白的作用，心梗后P2X7R可能抑制Cav-3合成；同时P2X7R介导NLRP3促炎症因子分泌作用，可能参与电和结构重构。因此我们提出P2X7R可能调控NLRP3和Cav-3通路促心梗后电和结构重构，触发室颤发生的假说。为了验证P2X7R触发室颤机制，本课题拟用野生型和P2X7R敲基因小鼠建立心梗模型，利用电生理检查和分子生物学检测明确电重构和结构重构发生；利用小干扰RNA干预特定通路蛋白表达，明确具体分子机制；利用全细胞膜片钳阐明对离子通道的作用。本研究将扩展对P2X7R功能的认识，有助于进一步揭示心梗后室颤发生和维持的机制，为心梗后室颤预防和治疗提供新的研究靶点。

Ventricular fibrillation (VF) is the most common arrhythmias for sudden cardiac death after myocardial infarction (MI), while the upstream regulation mechanisms spurring the formation of VF electrical and structural remodeling are yet to be determined. The applicant’s preliminary work found that the ionotropic purinergic receptor (P2X7R) and Cavoelin-3 (Cav-3) on ventricular cardiomyocytes were co-localized.Cav-3 is a protein anchored many ion channels, which may be down-regulated by P2X7R after MI. Additionally, P2X7R increases secretion of inflammatory cytokines through NACHT,LRR and PYD domain containing protein 3 (NLRP3), which may participate in electrical and structural remodeling. Therefore, we hypothesize that P2X7R, through NLRP3 and Cav-3 signalling pathways, promotes electrical and structural remodeling, and then spurring the occurrence of VF after MI. To test the mechanisms of occurrence of VF caused by P2X7R, in the present project, MI models will be established using wild-type and knockout mice, and the electrical and structural remodeling will be defined using electrophysiological examination and molecular biological testing; the expression of the specific proteins of signal pathways will be intervened by small interfering RNA to determine the exact mechanism; the influence to the ion channels will be determined by whole-cell patch clamp. This project will improve the understanding of biological functions of P2X7R and contribute to unveil the mechanisms of occurrence and maintenance of VF post MI, so as to provide new research target for the prevention and treatment of VF post MI.