Role of the Thrombin PAR-1 Pathway in Viral Infection

描述(申请人提供)：病毒感染在世界范围内造成相当大的发病率和死亡率。Toll样受体3(TLR3)在对病毒的先天免疫反应中发挥重要作用。作为宿主防御反应的一部分，病毒感染也会激活凝血系统。组织因子(Tf)和蛋白水解酶激活受体1(PAR-1)在病毒感染过程中可在多种细胞中诱导表达。然而，关于凝血和PARS在病毒感染中的作用的研究很少。我们观察到，抑制转铁蛋白或凝血酶，以及PAR-1的缺失显著增加了柯萨奇病毒B3(CVB3)诱导的心肌炎。PAR-1基因缺陷的小鼠也更容易感染甲型流感。TLR3激活心脏成纤维细胞(CFs)、心肌细胞(CMS)和肺上皮细胞，诱导干扰素(IFN)表达和干扰素调控的基因，如CXCL10，作为病毒感染免疫反应的一部分。我们发现PAR-1缺陷小鼠在病毒感染过程中降低了干扰素-β和CXCL10的表达。此外，PAR-1在CFs上的激活以p38依赖的方式增强了干扰素-β的表达。综上所述，这些结果表明，Tf-凝血酶-PAR-1途径在两种不同类型病毒感染的早期先天免疫反应中发挥着重要作用。我们将使用遗传学和药理学方法来确定TF、凝血酶和PAR-1在病毒感染中的作用。我们的建议包括三个具体目标。特异性目的1：探讨凝血因子、凝血酶和PAR-1在CVB3诱导的心肌炎中的作用。假设：CVB3感染后，依赖TF的凝血酶生成激活PAR-1并增加依赖干扰素的抗病毒程序。特异性目标2：确定PAR-1增强CFS和CMS中依赖TLR3的干扰素-β表达的机制。假设：PAR-1激活通过增加多种细胞内信号通路来增强TLR3依赖的干扰素基因的表达。特异性目标3：确定Tf、凝血酶和PAR-1在甲型流感肺部感染中的作用。假设：肺中依赖于TF的凝血酶生成和PAR-1激活有助于对甲型流感感染的先天免疫反应。我们的研究将阐明凝血系统和PAR-1如何在病毒感染的先天性免疫反应中起作用。

DESCRIPTION (provided by applicant): Viral infections cause considerable morbidity and mortality worldwide. Toll-like receptor 3 (TLR3) plays a major role in the innate immune response to viruses. The coagulation system is also activated by viral infections as part of the host defense response. Tissue factor (TF) and protease-activated receptor 1 (PAR-1) are induced in various cell types during viral infection. However, there are few studies on the roles of coagulation and PARs in viral infection. We observed that inhibition of TF or thrombin, as well as a deficiency of PAR-1 significantly increased coxsackievirus B3 (CVB3)-induced myocarditis. PAR-1 deficient mice were also more susceptible to infection with influenza A. Activation of TLR3 on cardiac fibroblasts (CFs), cardiac myocytes (CMs) and lung epithelial cells induces interferon ¿ (IFN-¿) expression and IFN-¿-regulated genes, such as CXCL10, as part of the immune response to viral infection. We found that PAR-1 deficient mice had reduced IFN-¿ and CXCL10 expression during viral infection. In addition, activation of PAR-1 on CFs enhanced IFN-¿ expression in a p38-dependent manner. Taken together, these results indicate that the TF-thrombin-PAR-1 pathway plays important roles in the early innate immune response to two different types of viral infections. We will use genetic and pharmacologic approaches to determine the roles of TF, thrombin and PAR-1 in viral infection. Our proposal consists of 3 specific aims. Specific Aim 1: Determine the roles of TF, thrombin and PAR-1 in CVB3-induced myocarditis. Hypothesis: Myocardial TF-dependent thrombin generation activates PAR-1 and increases the IFN- ¿-dependent anti-viral program after CVB3 infection. Specific Aim 2: Determine the mechanisms by which PAR-1 enhances TLR3-dependent IFN-¿ expression in CFs and CMs. Hypothesis: PAR-1 activation enhances TLR3-dependent IFN-¿ gene expression by increasing various intracellular signaling pathways. Specific Aim 3: Determine the roles of TF, thrombin and PAR-1 in influenza A infection of the lung. Hypothesis: TF-dependent thrombin generation and PAR-1 activation in the lung contributes to the innate immune response to influenza A infection. Our studies will elucidate how the coagulation system and PAR-1 contribute to the innate immune response to viral infection