HSF1通过抑制小胶质细胞XBP1/NLRP3/caspase-1信号通路改善脑缺血再灌注损伤的机制研究

Cerebral ischemia/reperfusion injury (CIRI) seriously affects the application of thrombolytic therapy and endovascular interventional therapy, and still lack of effective treatment. Heat-shock transcription factor 1 (HSF1) is the main regulator of the heat shock response. In our previous study, we found the overexpression of HSF1 plays a protective role in hypoxic-ischemic brain damage rats. However, the role of HSF1 in microglia is still unknown. It has been reported that HSF1 has the function that inhibits the X-box binding protein 1 (XBP1)-mediated inflammatory response in Kupffer cells (resident macrophages in liver tissue). Thus, we hypothesize that the HSF1 may has the function that inhibits the inflammatory response in microglia in the middle cerebral artery occlusion/ reperfusion mice model. In this study, we will use middle cerebral artery occlusion/ reperfusion mice model in vivo, and oxygen/glucose deprivation model in vitro to verify the hypothesis. The specific overexpression or inhibition of HSF1 was implemented by microglia-specific recombinant adeno-associated viruses both in vivo and vitro studies. The experimental techniques includes immunouorescence staining, western blot et al. were used to testing the effects of HSF1 on microglia XBP1/NLRP3/ caspase-1 pathway, inflammatory factors, blood-brain barrier and brain tissue injury. This study is helpful to improve our understanding in the mechanisms of CIRI and find the new therapies for CIRI patients.

脑缺血再灌注损伤（CIRI）是脑梗死患者溶栓、取栓治疗的严重并发症，缺乏有效的治疗措施。热休克转录因子1（HSF1）是热休克反应的主要调节因子，我们前期研究发现，在脑缺血缺氧大鼠神经元中，高表达HSF1可发挥神经元保护作用，但其在小胶质细胞中的作用不明确。有研究发现HSF1可抑制肝脏Kupffer细胞中X-盒结合蛋白1（XBP1）介导的炎症通路。根据前期研究结果，我们推测HSF1可通过抑制小胶质细胞中的炎症通路来减轻小鼠CIRI。本研究拟应用小鼠大脑中动脉缺血再灌注模型和小胶质细胞氧糖剥夺模型，通过小胶质细胞特异性腺相关病毒转染技术，实现在小胶质细胞中特异性过表达或抑制HSF1，并通过免疫荧光、免疫印迹等技术，研究HSF1对小胶质细胞XBP1/NLRP3/Caspase-1通路、炎性因子、血脑屏障和脑组织损伤程度的影响，以明确HSF1对CIRI调控作用的机制，为CIRI的治疗提供新的思路。

脑缺血再灌注损伤（CIRI）在接受血管再通治疗的脑梗死患者中十分常见，是影响预后的因素之一，但目前尚无有效的干预措施。炎症反应是脑缺血再灌注损伤的关键病理生理机制之一。既往研究表明，热休克转录因子1（HSF1）可以通过减轻炎症反应起到组织保护的作用，然而其在CIRI中的作用及其机制尚不明确。本研究通过体内、体外实验证实了HSF1通过抑制小胶质细胞的XBP1s/NLRP3/Caspase-1通路抑制卒中后炎性反应并减轻卒中后缺血再灌注损伤。①在原代小胶质细胞的氧糖剥夺模型中，过表达HSF1可以抑制小胶质细胞中的XBP1s/NLRP3/Caspase-1信号通路的激活、抑制小胶质细胞内炎性小体的形成，减少细胞因子IL-1β的产生。②在小胶质细胞中激活XBP1剪切、形成具有活性的XBP1s阻断了HSF1对小胶质细胞炎性反应的抑制作用，说明HSF1通过抑制XBP1的剪切及其下游NLRP3炎性小体的激活起到减轻炎症反应的作用。③在小胶质细胞中过表达HSF1可以减小小鼠大脑缺血再灌注损伤后的梗死体积，改善小鼠神经行为学评分；在机制方面，在小胶质细胞中过表达HSF1减少了脑缺血再灌注损伤后Cleaved caspase-1、NLRP3的表达，减少了梗死组织内IL-1β的浓度和中性粒细胞的浸润。通过本研究，我们阐明了HSF1改善脑缺血再灌注损伤的机制，为脑缺血再灌注损伤的治疗提供新思路。