HSF1抑制NLRP3炎症小体激活保护脓毒症急性肺损伤的机制研究

The acute lung injury (ALI) is one of the most common complications of sepsis，which results in high mortality of patients. It is demonstrated in our experiments that HSF1 knock out mice suffered more serious sepsis induced ALI than wild ones. IL-1β and IL-18 were increased higher in peripheral blood and bronchoalveolar lavage fluid, and the pulmonary expression of NLRP3 inflammasome was also increased greater compared with the wild type mice. RAW264.7 cells over-expressing HSF1 can inhibit the NLRP3 inflammasome activation induced by LPS. Combined our animal, cellular and molecular experiments, it is hypothesized that HSF1 can protect the ALI induced by sepsis in the following mechanisms: Firstly, HSF1 can directly bind the promoter of NLRP3 inflammasome genes and inhibit their expression. Secondly, HSF1 can inhibit NLRP3，IL-1βexpression via a NF-κB signal pathway inhibition caused by increased HSP70 and TAX1BP1. And finally, HSF1 can inhibit the post-translation activation of NLRP3 via increasing the ubiquitination enzyme complex composed of increased HSP90 and STG1. We plan to prove our hypothesis via preparing a septic model using HSF1 knockout mice, then investigating the protective effect of HSF1 on the priming and activation of NLRP3 in sepsis-induced ALI by animal, cellular and molecular experiments. It is expected that this project will elucidate the cellular and molecular mechanisms by which HSF1 alleviates sepsis induced ALI from a completely new angle of viewpoint and provide new targets and experimental evidences for intervention and treatment of both sepsis-induced ALI and sepsis patients .

脓毒症急性肺损伤（ALI）是导致脓毒症患者高死亡率的重要原因。申请者前期研究发现:HSF1基因敲除小鼠较野生型小鼠脓毒症ALI症状加重，血清及肺泡灌洗液IL-1β和IL-18增高，肺脏NLRP3炎症小体表达增加。RAW264.7细胞过表达HSF1可以抑制内毒素诱导的NLRP3炎症小体活化。据此本项目提出如下假说：HSF1抑制NLRP3炎症小体激活保护脓毒症ALI,其机制可能为：①直接结合并抑制NLRP3炎症小体基因表达；②上调HSP70、TAX1BP1表达而抑制NF-κB信号通路介导的NLRP3、IL-1β生成；③上调HSP90、SGT1表达，抑制NLRP3翻译后活化。针对上述假说，本项目拟采用HSF1基因敲除小鼠制备脓毒症模型，从整体、细胞及分子水平揭示HSF1通过转录及转录后修饰抑制NLRP3炎症小体激活保护脓毒症ALI的机制，为脓毒症ALI以及脓毒症的干预和治疗找到新的突破口。

课题组前期研究证明，HSF1通过抑制炎症细胞的迁移和浸润保护脓毒症急性肺损伤，减轻多器官损伤。然而，HSF1是否通过抑制NLRP3炎症小体激活保护脓毒症急性肺损伤，目前尚未见报道。本项目采用HSF1基因敲除小鼠制备脓毒症模型，收集脓毒症病人临床样本进行检测，从整体，细胞及分子水平对上述问题进行了深入探讨，主要发现如下：.1. HSF1能够降低脓毒症小鼠的死亡率，通过抑制炎症介质的释放保护脓毒症急性肺损伤。.2. HSF1能够抑制脓毒症小鼠肺组织中NLRP3炎症小体激活相关基因NLRP3,caspase-1,IL-1β和IL-18的mRNA和蛋白表达。.3. HSF1能够抑制小鼠腹腔原代巨噬细胞中NLRP3炎症小体激活相关基因NLRP3,caspase-1,IL-1β和IL-18的mRNA和蛋白表达。.4. HSF1通过从转录水平上调TRAF3的表达抑制NF-KB信号通路来抑制NLRP3炎症小体的激活。.5. SGT1在脓毒症病人外周血中表达降低，SGT1变化的程度和脓毒症病人的严重程度成正相关。HSF1通过从转录水平上调SGT1的表达，SGT1参与NLRP3的泛素化，最终从转录后水平抑制NLRP3炎症小体的活化来发挥保护作用。.. 本课题已发表基金标注论文8篇，其中通讯作者、并列通讯作者文章各一篇。待发表论文3篇。项目从全新角度揭示了HSF1抑制NLRP3的表达和活化减轻脓毒症肺损伤的细胞分子机理，为揭示脓毒症的发病机制和寻找新的干预措施提供了重要实验证据。