HSF1抑制脓毒症相关性急性肺损伤小鼠中性粒细胞浸润的机制

The applicant recently found that Heat shock factor 1 (HSF1) played a protective effect on LPS-induced acute lung injury(ALI) by suppression of PMN infiltration. However, the mechanism underlying the role of HSF1 in regulating PMN infiltration remains elusive. Previously, we prepared an LPS-induced systemic inflammatory response syndrome(SIRS) model to screen HSF1 regulated inflammation-related genes from the lung tissue by microarray with 384 inflammatory cytokine genes, using HSF1 knockout mouse. We found that HSF1 may inhibit the expression of P-selectin glycoprotein ligand 1 (PSGL-1, a cell adhesion molecule) and XCR1 (a chemokine receptor) gene. Our bioinformatic analysis found a heat shock element located at the upstream of the transcription starting sites of the psgl-1 and xcr1 genes. Therefore, as a transcription factor, HSF1 may repress psgl-1 and xcr1 directly at the transcriptional level, thus inhibit PMN adhesion and chemotaxis. Because PMN chemotaxis is closely related to changes of cytoskeletal protein such as F-actin, HSF1 may also affect F-actin polymerization. Based on these findings, this research project is attempted to investigate the effect of HSF1 on PMN adhension and chemotaxis, and to further explore the mechanism of the inhibitory action of HSF1 on PMN infiltration in the sepsis-related ALI mice by regulating expression of psgl-1 and xcr1 gene on PMN surface and F-actin polymerization, using HSF1 knock out mice with LPS injection (i.p.) or cecal ligation and puncture(CLP) to prepare sepsis-related ALI model, and mouse promyelocyte (MPRO) cell line with HSF1 overexpression as cell model. It is expected to provide novel ideas and experimental evidences for the prevention and treatment of the sepsis-related ALI/acute respiratory distress syndrome(ARDS).

申请者前期发现热休克因子1(HSF1)抑制LPS所致急性肺损伤(ALI)小鼠的中性粒细胞（PMN）浸润从而保护肺损伤，但HSF1抑制PMN浸润的机制还不清楚。本室前期从肺组织筛选HSF1 调控的炎症相关基因，发现HSF1可能抑制psgl-1和xcr1基因的表达，且这两个基因的启动子区都含热休克元件(HSE)，申请者推测HSF1可能通过与这两个基因启动子区HSE结合而直接抑制它们的转录，从而抑制PMN的粘附和趋化。另PMN趋化与F-actin等细胞骨架蛋白密切相关。本项目拟采用HSF1敲除小鼠经LPS刺激或盲肠结扎穿孔制备脓毒症相关ALI模型和采用LPS刺激HSF1过表达的MPRO模型，从正反两方面研究HSF1对PMN粘附和趋化的影响，深入探讨HSF1通过调控psgl-1和xcr1基因表达和F-actin聚合而抑制PMN浸润的机制，为脓毒症相关ALI/ARDS的防治提供新的思路和实验线索。

热休克因子1(HSF1)是调控热休克反应的主要转录因子。HSF1抑制LPS所致急性肺损伤(ALI)小鼠的中性粒细胞（PMN）浸润从而保护肺损伤。中性粒细胞浸润是涉及粘附和趋化作用的、受到精细调节的一个多步骤过程。本室前期从肺组织筛选HSF1 调控的炎症相关基因，发现HSF1可能抑制psgl-1和xcr1基因的表达，且这两个基因的启动子区都含热休克元件(HSE)，HSF1可能通过与这两个基因启动子区HSE结合而直接抑制它们的转录，从而抑制PMN的粘附和趋化。另PMN趋化与F-actin等细胞骨架蛋白密切相关。本项目通过采用HSF1敲除小鼠经LPS刺激制备脓毒症相关ALI模型，研究HSF1对PMN粘附和趋化的影响，探讨HSF1通过调控psgl-1和xcr1基因表达和F-actin聚合而抑制PMN浸润的机制，为脓毒症相关ALI/ARDS的防治提供新的思路和实验线索。