RNA:protein interactions that dictate the success of influenza virus infection

摘要 流感病毒是一种严重的公共卫生威胁，导致高水平的发病率和死亡率。常年性疾病 流感造成的负担给我们的医疗基础设施和经济带来了巨大的压力。这是尽管 通过每年接种疫苗、抗病毒药物治疗和其他医疗和公共服务来控制疾病的许多努力 健康干预。为了解决持续的健康和经济成本，显然需要更好地 了解流感病毒复制的分子机制以及如何操纵这些机制 治疗效果。流感病毒利用细胞因子和途径，在某些情况下还会颠覆 促进复制。我们确定了RNA：病毒和宿主伙伴之间影响先天的蛋白质相互作用 感染期间的免疫反应。我们证明了IFIT2是一种关键的细胞蛋白，可以将病毒的mRNAs与 增强复制能力。这是令人惊讶的，因为IFIT2是最早对病毒做出反应的蛋白质之一 感染，并显示广谱的抗病毒活性。IFIT2抗病毒活性的潜在机制， 以及它是如何被流感病毒增选为前病毒效应器的，目前尚不清楚。我们还展示了 流感核蛋白(NP)是一种与宿主RNA结合的关键病毒蛋白。这会将一个新活动分配给NP，该活动 我们的数据表明，这是一种以前未被认可的抑制先天性免疫反应的策略的一部分。整体而言 这项应用的目标是确定这些RNA：蛋白质复合体是如何由病毒和宿主组成的 这些组件操纵先天免疫反应，以支持病毒复制。在目标1中，我们调查IFIT2如何 在广泛作用的抗病毒反应中充当一线防御者。我们假设IFIT2增强了 翻译抗病毒蛋白，这是流感病毒为促进病毒生产而改变用途的事件 蛋白质。我们通过实验来测试这一点，该实验研究了IFIT2与靶RNA的结合过程， 影响其结合的mRNAs的翻译，改变感染。目标2询问相互作用的影响 病毒NP和宿主RNA。这一目的表明，NP：RNA复合体可以调节先天免疫反应。我们 通过研究RNA和感染诱导的激活先天免疫途径的事件来研究这一点，以及 辨别对病毒复制的影响。这项提议的结果将建立一种机械性的理解 调节先天免疫反应的病毒和宿主因素，以及流感病毒如何推动平衡 支持复制。此外，虽然我们的研究重点是流感病毒，但我们发现的潜在机制 将对宿主抗病毒反应和意外策略的一般理解产生广泛影响 被病毒用来中和它们。完成本建议书将提供基本知识，以便 有助于新的治疗方法或细胞靶点，可用于理性开发 抗流感病毒疗法。

ABSTRACT Influenza virus is a serious public health threat causing high levels of morbidity and mortality. The annual disease burden from influenza places a significant strain on our healthcare infrastructure and economy. This is despite many efforts to control disease with yearly vaccination, antiviral drug therapies, and other medical and public health interventions. To address the continuing health and economic costs, there is a clear need to better understand the molecular mechanisms of influenza virus replication and how these can be manipulated for therapeutic benefit. Influenza virus exploits, and in some cases subverts, cellular factors and pathways to promote replication. We identified RNA:protein interactions between viral and host partners that impact innate immune responses during infection. We showed IFIT2 is a critical cellular protein that binds viral mRNAs to enhance replication. This was surprising, as IFIT2 is one of the first proteins expressed in response to viral infection and displays broad-spectrum antiviral activity. The mechanisms underlying the antiviral activity of IFIT2, and how this is co-opted into a proviral effector by influenza virus, are not yet known. We also showed that influenza nucleoprotein (NP) is a key viral protein that binds host RNAs. This assigns a new activity to NP that our data suggest is part of a previously unappreciated strategy to dampen innate immune responses. The overall goal of this application is to determine how these RNA:protein complexes composed of both viral and host components manipulate innate immune responses to support viral replication. In Aim 1, we investigate how IFIT2 functions as a front-line defender in a broadly acting antiviral response. We hypothesize that IFIT2 enhances translation of antiviral proteins, an event that is repurposed by influenza virus to promote production of viral proteins. We test this using experiments that investigate the processes by which IFIT2 engages target RNAs, affects translation of its bound mRNAs, and alters infection. Aim 2 interrogates the impact of interactions between viral NP and host RNAs. This aim proposes that NP:RNA complexes moderate innate immune responses. We investigate this by studying RNAs and infection-induced events that activate innate immune pathways, and discern the impact on viral replication. The results from this proposal will establish a mechanistic understanding of the viral and host factors regulating innate immune responses and how influenza virus tips the balance to favor replication. Moreover, while our studies focus on influenza virus, the underlying mechanisms we discover will have broad impacts on the general understanding of host antiviral responses and unexpected strategies used by viruses to counteract them. Completion of this proposal will provide fundamental knowledge that can contribute to new therapeutic approaches or cellular targets that can be exploited for the rational development of anti-influenza virus therapies.