Role of the Thrombin PAR-1 Pathway in Viral Infection

描述（由申请方提供）：病毒感染在全球范围内引起相当大的发病率和死亡率。Toll样受体3（TLR 3）在针对病毒的先天性免疫应答中起主要作用。凝血系统也被病毒感染激活，作为宿主防御反应的一部分。组织因子（TF）和蛋白酶激活受体1（PAR-1）在病毒感染过程中在各种细胞类型中被诱导。然而，关于凝血和PAR在病毒感染中的作用的研究很少。我们观察到，TF或凝血酶的抑制，以及PAR-1的缺陷显着增加柯萨奇病毒B3（CVB 3）诱导的心肌炎。PAR-1缺陷小鼠也更容易感染甲型流感。心脏成纤维细胞（CF）、心肌细胞（CM）和肺上皮细胞上的TLR 3的活化诱导干扰素（IFN-γ）表达和IFN-γ调节的基因，如CXCL 10，作为对病毒感染的免疫应答的一部分。我们发现PAR-1缺陷小鼠在病毒感染期间IFN-γ和CXCL 10表达减少。此外，激活CF上的PAR-1以p38依赖的方式增强IFN-γ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应答中起重要作用。我们将使用遗传学和药理学的方法来确定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。具体目的1：明确TF、凝血酶和PAR-1在CVB 3诱导的心肌炎中的作用。假设：CVB 3感染后，心肌TF依赖性凝血酶生成激活PAR-1并增加IFN-γ依赖性抗病毒程序。具体目标2：确定PAR-1增强CFs和CMs中TLR 3依赖性IFN-γ表达的机制。假设：PAR-1激活通过增加各种细胞内信号通路增强TLR 3依赖性IFN-γ基因表达。具体目标3：确定TF、凝血酶和PAR-1在肺部甲型流感感染中的作用。假设：肺中TF依赖性凝血酶生成和PAR-1活化有助于对甲型流感感染的先天免疫应答。我们的研究将阐明凝血系统和PAR-1如何参与病毒感染的先天免疫反应

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