Deciphering the complexities of inflammasome activation following RSV infection

摘要 呼吸道合胞病毒(RSV)是引起儿童、老年人和老年人严重呼吸道疾病的主要原因。 免疫受损的人，目前还没有获得许可的RSV疫苗。宿主炎症性 RSV感染后的反应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毒株在调节宿主炎症反应中的作用。产品的生产 促炎症细胞因子IL-1、β和IL-6已被发现在呼吸道中显著增加 患有严重疾病的婴儿。此外，据报道，RSV感染会促进老年人的高代谢。 呼吸道合胞病毒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体严密调控。炎症小体的激活是两个- 分步过程，包括启动和激活步骤，需要对细胞进行代谢重新编程。 以往的研究表明，RSV A2感染可诱导NLRP3激活 炎症者。我们的初步数据表明，感染RSV2-20毒株会导致显著的 与感染A2毒株相比，IL-1β的产生增加。我们还观察到， RSV2-20感染的巨噬细胞与A2感染的巨噬细胞的糖酵解。没想到，当 我们用重组RSV A2毒株感染细胞，重组RSV A2毒株被设计成表达2-20融合(F)蛋白，称为 A2/2-20F，我们观察到巨噬细胞中IL-1β的产生和糖酵解的显著增加。因此，我们的 令人振奋的新的初步数据表明，RSV毒株不同地激活炎症体，而这种毒株- 依赖增加的炎性小体激活是由F蛋白介导的。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 了解调节宿主免疫反应和疾病严重程度的病毒衍生因素 呼吸道合胞病毒感染。此应用程序的目标是确定炎症小体中发生的变化 呼吸道合胞病毒感染后的信号和代谢。此外，我们还将探讨这些变化如何影响先天 细胞重新聚集到肺中，并塑造随后的适应性免疫反应。我们的中心假设是 RSV 2-20株增强了炎症体的启动和激活信号，从而增加了 中性粒细胞内流和Th17反应。我们将通过以下方式实现上述目标： 目的1.确定RSV F蛋白介导的炎性小体的机制 激活。目的2.研究不同的炎性小体激活对免疫细胞募集和 呼吸道合胞病毒感染后的疾病。从这些研究中获得的知识将提供一种机械的 了解呼吸道合胞病毒介导的炎症反应。此外，这些研究将极大地影响 评价治疗目标和设计未来的RSV候选疫苗。

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.