REGULATION OF INFLUENZA VIRUS INFECTION BY ISG15

描述（由申请人提供）：最近高致病性流感病毒的爆发突出了更好地了解流感病毒与其宿主之间相互作用的必要性。病毒感染触发迅速的抗病毒应答，其中I型干扰素（IFN）通过上调大量IFN刺激基因（ISG）在协调宿主应答中发挥核心作用。一些ISG具有直接的抗病毒活性，而其他ISG则通过调节免疫系统影响抗病毒反应。我们最近已经表明，这些ISG之一，ISG15，作为一个关键的IFN诱导的抗病毒分子的功能。ISG15是一种泛素同源物，其被IFN、toll受体连接和病毒感染强烈上调。ISG 15缺陷型小鼠在感染几种病毒（包括甲型流感病毒和B流感病毒）后显示出增加的致死率。然而，ISG15发挥这种抗病毒活性的机制尚不清楚。ISG15与多种细胞内蛋白质结合，靶向许多生物过程。人ISG15也从细胞中释放，并作为细胞因子发挥作用，激活各种免疫细胞。在本提案中，我们将检验ISG15与靶蛋白的偶联导致呼吸道上皮内病毒复制的抑制并允许宿主随后清除病毒的假设。我们将通过以下两个目标来检验这一假设。目的1中的研究将探索ISG15调节呼吸道上皮内病毒复制的机制。我们还将确定ISG15在这种细胞类型中的表达是否足以控制流感病毒感染。目的2中的研究将确定ISG15的抗病毒活性是否需要ISG15的缀合。我们将确定ISG15是否与病毒蛋白结合并调节病毒复制。从这些研究中获得的结果将为新鉴定的抗病毒分子ISG15的潜在作用机制提供重要的见解。ISG 15作为一种重要的抗病毒分子发挥作用，具有抗多种人类病原体的活性，包括甲型流感病毒和B型流感病毒。本研究将通过研究其作用范围和与靶蛋白偶联的需要来探讨其在流感病毒感染过程中的作用机制。这些研究可能为对抗病毒感染提供潜在的新治疗靶点。公共卫生相关性：ISG 15作为一种重要的抗病毒分子发挥作用，具有抗多种人类病原体的活性，包括甲型流感病毒和B型流感病毒。本研究将通过研究其作用范围和与靶蛋白偶联的需要来探讨其在流感病毒感染过程中的作用机制。这些研究可能为对抗病毒感染提供潜在的新治疗靶点。

DESCRIPTION (provided by applicant): Recent outbreaks of highly pathogenic influenza virus have highlighted the need for a better understanding of the interactions between influenza virus and its host. Viral infection triggers a prompt anti-viral response, with type I interferons (IFNs) playing the central role in coordinating the host response through the upregulation of a large number of IFN stimulated genes (ISGs). Several ISGs have direct antiviral activity, while others impact upon the antiviral response by modulating the immune system. We have recently shown that one of these ISGs, ISG15, functions as a critical IFN induced anti-viral molecule. ISG15 is an ubiquitin homolog that is strongly upregulated by IFNs, toll receptor ligation, and viral infection. ISG15 deficient mice display increased lethality following infection with several viruses, including both influenza A and B viruses. Yet the mechanism by which ISG15 exerts this antiviral activity is unknown. ISG15 conjugates to a wide array of intracellular proteins, targeting numerous biological processes. Human ISG15 is also released from cells and functions as a cytokine, activating various immune cells. In this proposal we will test the hypothesis that the conjugation of ISG15 to target proteins results in the inhibition of viral replication within the respiratory epithelium and allows for subsequent clearance of the virus by the host. We will test this hypothesis with the following two aims. The studies in Aim 1 will explore the mechanism by which ISG15 regulates viral replication within the respiratory epithelium. We will also determine if expression of ISG15 within this cell type is sufficient to control influenza virus infection. The studies in Aim 2 will determine if conjugation of ISG15 is required for the antiviral activity of ISG15. We will determine if ISG15 conjugates to viral proteins and regulates viral replication. The results obtained from these studies will provide important insight into a potential mechanism of action for a newly identified antiviral molecule, ISG15. ISG15 functions as a critical antiviral molecule, with activity against several human pathogens, including both influenza A and B viruses. This proposal will explore its mechanism of action during influenza virus infection by investigating its sight of action and requirement for conjugation to target proteins. These studies may provide insight into a potential new therapeutic target in the fight against viral infections. PUBLIC HEALTH RELEVANCE: ISG15 functions as a critical antiviral molecule, with activity against several human pathogens, including both influenza A and B viruses. This proposal will explore its mechanism of action during influenza virus infection by investigating its sight of action and requirement for conjugation to target proteins. These studies may provide insight into a potential new therapeutic target in the fight against viral infections.