甲型流感病毒感染对脑血管功能的影响机制

Influenza A virus is the most common infectious pathogen in humans and causes significant morbidity and mortality, particularly in infants and the elderly population. Severe influenza is characterized by cytokine storm and multiorgan failure. Our previously research has found that, upregulation of ectopic trypsin in the brain could be induced after influenza A virus infection, which plays an important role in the development of encephalitis. Based on the hypothesis of influenza virus–cytokine-protease cycle, The aim of this study was to define the molecular mechanisms of the expression of protease after severe influenza. In this study, we propose to make an encephalitis model and research the Toll like receptor (TLRs) signaling pathways in mediating ectopic trypsin expression after WSN virus infection. After blocking TLR - MyD88 / TRIF - NF-kB/AP - 1 signaling pathway, the activity of ectopic trypsin and matrix metal proteinase (MMP-9) will be analyzed. Levels of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-1βwill also be detected. These common effects were thought to cause the degradation of tight junction and extracellular matrix, and resulting in vascular hyperpermeability and dysfunction. We will also verified the mechanism of signal transduction in human vascular endothelial cells. The expression of trypsin in the cells will be detected after blocking the TLRs pathway, using NF-kB and AP-1 inhibitors, silencing protease gene or using protease inhibitor. If we clarify the molecular mechanism of vascular dysfunction in severe influenza, it may provide a new method for clinical treatment of encephalitis.

甲型流感病毒是人类最常见的病原体之一。我们发现严重的甲型流感病毒感染可以诱导脑组织中的异位胰蛋白酶表达上调，而这种蛋白水解酶能破坏血脑屏障最终导致病毒性脑炎的发生。本研究拟通过甲型流感病毒(WSN/33,H1N1)感染小鼠制作病毒性脑炎模型，研究脑组织中Toll样受体信号通路介导异位胰蛋白酶表达的分子机制。通过分层阻断TLR-MyD8 8/TRIF-NF-κB/AP-1信号通路，分析该信号通路对异位胰蛋白酶表达和活性的影响。通过监测炎症细胞因子的表达水平，以及研究异位胰蛋白酶激活金属蛋白酶对降解细胞外基质和紧密连接的影响，探明异位胰蛋白酶破坏血脑屏障的机制。同时在血管内皮细胞中验证这一结论，通过阻断TLRs通路、抑制NF-κB和AP-1、沉默蛋白酶基因和使用蛋白酶抑制剂等不同手段干预，阐明TLRs对异位胰蛋白酶表达的调控机制，为有效防治此类疾病提供理论依据。

甲型流感病毒是一种人类中常见的致病性病原体，已有研究发现严重的甲型流感病毒感染可以诱导脑组织中的异位胰蛋白酶表达上调，而这种异位胰蛋白酶能破坏血脑屏障，最终导致病毒性脑炎的发生，引起严重不良后果。本项目通过甲型流感病毒（WSN/33，H1N1）感染制作病毒性脑炎小鼠模型，研究小鼠脑组织中TLR7信号通路参与甲型流感病毒感染所致的病毒性脑炎的分子机制，分析该信号通路对小鼠脑组织中异位胰蛋白酶和金属蛋白酶表达的诱导过程，研究对破坏血脑屏障和降解细胞外基质以及紧密连接蛋白的影响，同时监测各种促炎症细胞因子的表达水平和小鼠的生存曲线，阐明TLR7对病毒性脑炎发病的调控机制，而阐明这一过程的分子生物学机制，就可能为临床上有效防治此类病毒性脑炎提供理论依据。