Deciphering the complexities of inflammasome activation following RSV infection

摘要 呼吸道合胞病毒（RSV）是儿童、老年人和 在某些实施方案中，RSV疫苗用于免疫功能低下的个体，并且目前没有许可的RSV疫苗。宿主炎症 RSV感染后，应答被认为有助于疾病的严重程度。目前所知的要少得多 关于RSV株在调节宿主炎症反应中的作用。生产 已经发现促炎细胞因子IL-1β和IL-6在呼吸道中显著增加 患有严重疾病的婴儿。此外，据报道RSV感染可促进糖尿病患者的高代谢。 RSV感染儿童的上呼吸道细胞。IL-1β是一种关键的促炎细胞因子，其分泌是 由称为炎性小体的多蛋白复合物紧密调控。炎性小体的激活是一个两- 步骤过程，包括引发和活化步骤，其需要细胞的代谢重编程。 先前的研究已经证明，RSV A2感染诱导NLRP 3的活化， 炎性小体我们的初步数据表明，感染RSV 2-20株导致显著的 与用A2菌株感染相比，IL-1β产生增加。我们还观察到， 与A2感染的巨噬细胞相比，RSV 2-20感染的巨噬细胞中的糖酵解。没想到等 我们用重组RSV A2株感染细胞，该重组RSV A2株被工程化以表达2-20融合（F）蛋白，称为 A2/2- 20 F，我们观察到巨噬细胞中IL-1β产生和糖酵解的显著增加。所以我们 令人兴奋的新的初步数据表明，RSV株不同地激活炎性小体，并且该株- 依赖性增加的炎性小体活化由F蛋白介导。因此，重要的知识差距 存在关于RSV衍生基因如何调节宿主炎症反应的问题。我们的长期目标是 了解病毒衍生的因素，调节宿主的免疫反应和疾病的严重程度， RSV感染。本申请的目的是确定炎性小体中发生的变化， RSV感染后的信号传导和代谢。此外，我们将探讨这些变化如何影响先天性 细胞募集到肺中并形成随后的适应性免疫应答。我们的核心假设是 RSV 2-20株增强炎性小体引发和激活信号，导致RSV 2-20的表达增加。 中性粒细胞流入和Th 17应答。我们将通过以下方式实现上述目标： 具体目标有两个：目标1。RSV F蛋白介导炎性小体的机制探讨 activation.目标二。检查差异性炎性小体激活对免疫细胞募集的作用， RSV感染后的疾病。从这些研究中获得的知识将提供一个机械的 了解RSV介导的炎症反应。此外，这些研究将极大地影响 治疗靶点的评估和未来RSV疫苗候选物的设计。

Abstract Respiratory syncytial virus (RSV) is a leading cause of severe respiratory disease in children, the elderly and immunocompromised individuals and there is currently no licensed RSV vaccine. The host inflammatory response is believed to contribute to disease severity following RSV infection. Much less is currently known regarding the role of RSV strains in modulating the host inflammatory response. The production of proinflammatory cytokines IL-1β and IL-6 have been found to be significantly increased in the respiratory tract of infants with severe disease. In addition, RSV infection has been reported to promote hypermetabolism in the upper respiratory cells of RSV-infected children. IL-1β is a key proinflammatory cytokine and its secretion is tightly regulated by multi-protein complexes named inflammasomes. Activation of the inflammasome is a two- step process, including priming and activation steps, that requires metabolic reprogramming of the cell. Previous studies have demonstrated that RSV A2 infection induces the activation of the NLRP3 inflammasome. Our preliminary data illustrate that infection with the RSV 2-20 strain results in significantly increased IL-1β production as compared to infection with the A2 strain. We also observe an increase in glycolysis in RSV 2-20 infected macrophages as compared to A2 infected macrophages. Unexpectedly, when we infect cells with a recombinant RSV A2 strain engineered to express the 2-20 fusion (F) protein, termed A2/2-20F, we observe a significant increase in both IL-1β production and glycolysis in macrophages. Thus, our exciting new preliminary data indicate that RSV strains differentially activate the inflammasome and this strain- dependent increased inflammasome activation is mediated by the F protein. Thus, important knowledge gaps exist regarding how RSV-derived genes modulate the host inflammatory response. Our long-term goal is to understand the virus-derived factors that modulate the host immune response and disease severity following RSV infection. The objective of this application is to determine the changes that occur in inflammasome signaling and metabolism following RSV infection. Moreover, we will explore how these changes impact innate cell recruitment into the lung and shape the subsequent adaptive immune response. Our central hypothesis is that the RSV 2-20 strain enhances both inflammasome priming and activation signals resulting in increases in both neutrophil influx and the Th17 response. We will achieve the goals outlined above by pursuing the following two specific aims: Aim 1. Determine the mechanism of RSV F protein-mediated inflammasome activation. Aim 2. Examine the role of differential inflammasome activation on immune cell recruitment and disease following RSV infection. The knowledge gained from these studies will provide a mechanistic understanding of RSV-mediated inflammatory responses. In addition, these studies will greatly impact the evaluation of therapeutic targets and design of future RSV vaccine candidates.