SOCS3 对流感病毒诱发急性肺损伤调控机制研究

In this project, we will investigate whether SOCS3 expressed in different cells regulates the pathogenesis of influenza-induced acute lung injury by infecting the SOCS3 conditionally-depleted mice with influenza virus. We particularly focus on SOCS3 depletion in lung epithelial cells (SOCS3fl/flSPCCre+), granulocytes (SOCS3fl/flLysMCre+), and CD4+ T cells (SOCS3fl/flCD4Cre+). We will analyze the expression of SOCS3 in the lung epithelial cells, granulocytes, and CD4+ T cells before and after lung infection with influenza virus (PR8). We also study the SOCS3 signaling pathway after influenza infection in the cultured A549 cell line. Finally, we will observe the effects of SOCS3 in the different cells by intratracheally challenging SOCS3 conditional knocked-out mice with influenza virus to evaluate the changes of the body weight loss (an index of mortality),lung wet-dry weight ratio (an index of pulmonary edema), and BAL proinflammatory cells and cytokines at different time points. The viral titre and histopathology in the infected lung will also be examined. For the first time, we will elucidate whether SOCS3 in the different cell population determine the proinflammatory responses and viral replication in the influenza-induced acute lung injury. We believe that this study will provide us new insights into mechanisms and novel strategies for intervening influenza lung infection.

本研究利用SOCS3在肺上皮细胞，粒细胞和CD4+T细胞上条件性缺失的小鼠模型，探索SOCS3在体内对于流感病毒诱发急性肺损伤中的调控作用及其分子机制。我们首先分析在流感病毒（IAV）感染前后SOCS3在小鼠肺组织及各个浸润细胞上的表达情况。然后在细胞水平上研究在IAV感染时SOCS3调控的信号通路及分子机制。最后本研究将用IAV感染各转基因小鼠（SOCS3fl/flSPCCre+、SOCS3fl/flLysMCre+和SOCS3fl/fl CD4Cre+），观察小鼠的体重下降及肺脏中肺水的变化；观察小鼠BAL中炎症细胞及炎症因子的表达；并测定小鼠肺脏中病毒滴度的动态变化；最后用病理切片分析感染小鼠肺损伤的情况。本研究首次探索在IAV感染时SOCS3在不同细胞上的调控作用对肺损伤及病毒复制的影响，为研究新的控制流感病毒诱发肺损伤的方法提供新理论依据和靶点，具有重大的应用价值。

摘要：本研究利用SOCS3在体细胞、肺上皮细胞、粒细胞、CD4+T和CD8+T细胞上条件性缺失的小鼠模型，探索SOCS3在体内对于流感病毒诱发急性肺损伤中的调控作用及其分子机制。我们首先研究了流感病毒（IAV，PR8）感染后小鼠肺组织SOCS3的表达情况，然后用PR8感染各转基因小鼠（SOCS3fl/flROSA26CreErt2+、SOCS3fl/flSPCCre+、SOCS3fl/flLysMCre+、SOCS3fl/flCD4Cre+和SOCS3fl/fl LckCre+分别表示SOCS3基因在体细胞，肺上皮细胞，巨噬细胞，CD4+T及CD8+T细胞上缺失），观察小鼠的体重下降及肺脏病毒复制及炎症因子表达的变化。研究结果显示，体细胞上缺失SOCS3小鼠感染PR8后其存活率较对照组显著降低，表明SOCS3在控制流感病毒感染引起的肺损伤中起着关键的作用。肺上皮细胞缺失SOCS3小鼠感染PR8，该小鼠在第7和8天较对照小鼠体重显著下降以及感染第6天时肺组织中病毒复制显著增加。同时在肺组织中STAT3 mRNA 水平显著升高。巨噬细胞上敲除SOCS3基因小鼠在PR8感染的早期（第1至第4天）体重下降较对照组显著增多,并且感染后第3天小鼠支气管灌洗液（BAL）中蛋白浓度也显著升高，表明敲除小鼠肺部炎症反应较对照组加重;但是病毒复制减少。在CD4+T与CD8+T 细胞上分别缺失SOCS3小鼠，感染PR8后体重下降较对照组小鼠组显著。本研究结果表明在IAV感染时SOCS3在不同细胞上对流感病毒复制及其引起的炎症、损伤起着关键作用。SOCS3可能是流感防治的重要靶点。