PLC-γ1信号通路介导经典途径细胞焦亡在类风湿性关节炎中的作用及机制研究

Pyroptosis which is known as inflammatory cell death induces severe inflammatory reaction. Inflammatory reaction is the important link of rheumatoid arthritis (RA). PLC-γ1 signal pathway can induce intracellular Ca2+ mobilization. Researches have demonstrated that highly concentration of Ca2+ is the crucial elements for activation of inflammasome and pyroptosis. In our preliminary study, we found that PLC-γ1 and pyroptosis-related factors NLRP3 and caspase-1 had high expression in RA synovial tissues. Thus, we propose that PLC-γ1/IP3/Ca2+ signal pathway induce intracellular Ca2+ mobilization and then activate NLRP3/caspase-1/GSDMD canonical pathway to promote the maturation and release of inflammatory factors which finally lead to severe intra-articular inflammatory reaction. Therefore, we will perform immunohistochemistry, western blot, scanning electron microscope, inhibitors of pyroptosis pathway and so on to confirm the role of pyroptosis and the detailed pyroptosis pathway in RA. Cre/loxp system was used to establishment PLC-γ1gene knocked-out mice; RA mice model was obtained by using collagen induced arthritis (CIA) method. Immunohistochemistry, Micro-CT, western blot, ELISA, scanning electron microscope and inhibitors of PLC-γ1 signal pathway were performed to elucidate the role and mechanism of PLC-γ1 signal pathway in pyroptosis. This research will provide a new target for the treatment of RA.

细胞焦亡可以介导强烈的炎症反应，而炎症反应是类风湿性关节炎（RA）中重要的一环。PLC-γ1信号通路促使胞内钙动员。研究已证实细胞内高浓度Ca2+是NLRP3炎症小体激活启动焦亡的重要因素。我们的前期研究发现：RA滑膜组织中高表达PLC-γ1和焦亡相关因子NLRP3、caspase-1。因此，我们提出假说：PLC-γ1/IP3/Ca2+信号通路促使胞内钙动员，进而激活NLRP3/caspase-1/GSDMD焦亡经典途径，促进炎症因子的成熟和释放，导致关节内严重的炎症反应。本项目拟运用western blot（WB）、扫描电镜和焦亡通路抑制剂等明确焦亡在RA中的作用以及发挥作用的具体通路；构建PLC-γ1基因敲除小鼠，并构建小鼠RA模型等，采用免疫组化、Micro-CT、WB和PLC-γ1信号通路抑制剂等阐明PLC-γ1信号通路在焦亡中的作用及机制。本项目将为RA的治疗提供新思路、新靶点。

类风湿性关节炎（RA）发病机制复杂，病因未明，患者常因迁延不愈的关节炎症导致关节软骨和骨破坏，最终导致关节畸形，丧失劳动力，给社会和家庭带来严重负担。近年来，细胞焦亡已被证实与多种疾病有关，它可以介导强烈的炎症反应，而炎症反应是RA中重要的一环。PLC-γ1信号通路促使胞内钙动员，研究已证实细胞内高浓度Ca2+是NLRP3炎症小体激活启动焦亡的重要因素。本项目围绕细胞焦亡在RA中的作用进行研究，通过细胞、组织和动物实验，发现细胞焦亡参与RA的炎症反应，细胞焦亡通过经典途径焦亡，即NLRP3/caspase-1途径介导炎症因子释放，抑制PLC-γ1表达可以降低NLRP3/caspase-1介导的炎症因子IL-1β、IL-18等的释放，从而减轻炎症反应，改善RA的症状。本研究表明细胞焦亡经典途径RA的疾病过程中发挥作用，PLC-γ1/IP3/Ca2+通路激活细胞经典途径焦亡，促进炎症因子的释放，导致关节内严重的炎症反应。本研究有助于进一步理解RA疾病过程中炎症反应的介导途径，为今后RA的相关研究开辟新的思路，细胞焦亡经典途径有望成为RA治疗的新靶点。