靶向Jak-STAT信号通路以阻断"细胞因子风暴"介导的重症H1N1肺脏免疫损伤及其机制研究

Influenza A viruses cause recurrent outbreaks at local or global scale with potentially severe consequences for human health and the global economy. Influenza virus induced pathology has been linked to disregulated immune responses and cytolysis mediated by viral replication in the lung. Our recent reports indicated that hypercytokinemia caused severe lung pathological lesions and NK cells hyperactivation was involved in the pathology of severe 2009 pandemic influenza infected mice. Cytokine signal was critical for acute lung injury in response to pulmonary influenza infection. This project intends to find a hypercytokinemia induced common signaling pathway, achieving moderate control the H1N1 induced inflammatory response but not NK cell antiviral effect through simultaneous blockade of common signal pathway. Based on our previous in-depth study of the Jak-STAT signal pathway and established mouse model of severe H1N1 pneumonia, we found that inflammatory cytokines/chemokines were dysregulation in BALF and lung, and NK cells were increased and highly activated. This project further study the hypercytokinemia induced activation of common signaling pathway Jak-STAT3/1. Whether inhibition of STAT3/1 blocked a variety of inflammatory factors at the transcriptional level was also analyzed. The critical role and molecular mechanisms of STAT3/1 in the H1N1 induced lung immune injury will also be clarified. Simultaneously, the therapeutic effects of combined STAT3/1 inhibitors and oseltamivir, not only reducing tissue damage but also inhibiting viral replication, were also be evaluated. Blocking the hypercytokinemia activated common transcription factor STAT3/1 provide new ideas for severe influenza pathogenesis and immunotherapy.

重症甲型H1N1流感引发肺脏免疫损伤,我们前期研究证明H1N1诱发"细胞因子风暴"并招募NK细胞是介导肺脏免疫损伤的主因。本课题拟寻找可群谱性阻断"细胞因子风暴"的共同信号通路,以达到适度控制H1N1诱导的炎症反应而保留NK细胞抗病毒效应的目的。我们拟采用前期Jak-STAT信号通路阻断技术,应用已建立的重症H1N1肺炎小鼠模型，在已经发现肺泡灌洗液(BALF)和肺脏炎性因子/趋化因子失调及其NK数目增多的基础上,进一步研究共同激活信号通路Jak-STAT3/1的活化情况，研究阻断STAT3/1通路在转录水平群谱性阻断细胞因子风暴的可行性,阐明STAT3/1在H1N1肺脏免疫损伤中的作用及分子机制。同时,联合STAT3/1抑制剂和达菲，观察既减轻组织损伤又抑制病毒复制对H1N1 的治疗效果。本研究以阻断共同活化转录因子STAT3/1为干预靶点,可能为重症流感的发病机制及免疫治疗提供新线索。

甲型H1N1流感病毒感染严重影响人类健康。其介导的急性肺脏免疫病理损伤可能是决定H1N1病人疾病严重程度的关键因素和致死主因。但甲型H1N1流感病毒诱导免疫病理损伤机制尚不完全清楚。深入了解甲型流感病毒诱导肺损伤的发病和致死机制，对降低甲型流感致死率和临床重症病人的治疗具有重要意义。我们前期研究发现细胞因子风暴参与肺脏免疫损伤，由于细胞因子具有清除H1N1病毒和导致肺脏免疫损伤的双刃剑功能，本研究以“细胞因子”是核心，向上寻找产生炎性细胞因子的主要细胞，向下寻找细胞因子活化的信号通路及如何“群谱性”阻断这些细胞因子通路。研究结果主要包括①甲型H1N1流感病毒的重症感染可以诱导肺脏，胸腺等多器官的损伤，是造成致死的重要原因。②本研究利用重症甲型H1N1流感小鼠模型，在细胞和分子水平探讨“细胞因子风暴”介导的STAT和mTOR信号通路在重症甲型H1N1感染诱导过度免疫应答、继而引发肺脏免疫病理损伤的机制；联合其抑制剂和抗病毒药物奥司他韦可降低病毒滴度，减缓过度炎症反应，从而提高重症感染小鼠生存率，发现STAT和mTOR信号通路是降低流感病毒诱导肺脏免疫损伤的有效靶点。③发现并证明重症甲型H1N1流感病毒能诱导胸腺萎缩，并阐述其部分机制是通过活化innate CD8+CD44hiCD122+Eomes+ SP T细胞分泌IFN-γ。④肺脏中γδ T细胞在感染早期的过度活化参与肺脏免疫病理损伤，机制为Vγ4+γδ T细胞亚群通过分泌IL-17A介导免疫损伤。⑤证明重症感染后NK细胞被招募到肺脏局部活化参与清除病毒和免疫损伤。寻找“群谱性”阻断多种细胞因子的方法及对临床治疗的作用，深入研究寻找既降低过高炎症反应又不影响抗病毒中和抗体产生的策略，为临床重症流感病人的干预治疗提供实验依据。