Mechanisms of Host Response Modulation by RSV Non-Structural Proteins

人类呼吸道合胞病毒(RSV)是导致严重急性呼吸道感染的主要原因，包括儿童、老年人和免疫功能低下的人，因此对人类健康具有全球性影响。尽管如此，可用于RSV感染的预防和特定治疗选择有限。呼吸道合胞病毒非结构蛋白NS1和NS2是呼吸道合胞病毒在肺炎病毒中所特有的，它们发挥着多种主要作用，被认为可以增强病毒感染并防止随后的RSV再感染。然而，仍有许多问题与RSV病毒编码的蛋白质如何塑造宿主反应有关。我们未发表的初步研究表明，在生理相关的细胞培养模型中，NS1分裂到细胞核，与免疫反应基因的启动子和增强子结合染色质，并影响宿主基因的转录。此外，我们观察到核NS1与病毒蛋白NS2和基质(M)相互作用，这表明RSV病毒蛋白进一步调节了细胞核中的宿主因子。人们对这些观察结果的功能相关性知之甚少。基于这些新的发现，并填补这一知识空白，我们建议确定NS1作为RSV感染过程中表观基因组和宿主反应的主要调节器的分子机制。核NS1还可能在加强免疫逃避的同时扭曲抗病毒反应，从而促进病毒的致病。我们的团队在生物化学/结构生物学、表观遗传学、转录调控和肺病学方面拥有互补的专业知识，将确定RSV NS1对宿主表观遗传转录控制的影响，定义和表征有助于NS1核质运输的分子相互作用，并确定RSV NS2和M蛋白相互作用对NS1核功能的影响。为了获得机理上的见解并评估这些观察结果在病毒感染期间的影响，我们将使用一种方法，将生化、结构、遗传、细胞和病毒学研究整合到相关细胞培养模型中，包括原代人肺来源细胞。通过完成这些协同目标，我们希望对疾病的关键贡献者提供见解，并为抗病毒和疫苗开发确定新的目标。

Human respiratory syncytial virus (RSV) is responsible for a major fraction of severe acute respiratory tract infections, including pediatric, elderly, and immunocompromised individuals, and thus has a global impact on human health. Despite this, there are limited prophylactic and specific treatment options available for RSV infections. RSV nonstructural proteins NS1 and NS2, which are unique to RSV among the pneumoviruses, play multiple major roles that are thought to enhance viral infection and to prevent protection from subsequent RSV reinfection. However, many questions remain that are related to how RSV virally encoded proteins shape the host response. Our unpublished preliminary studies show that NS1 partitions to the nucleus in physiologically relevant cell culture models, binds chromatin at promoters and enhancers of immune response genes, and impacts host gene transcription. In addition, we observe that nuclear NS1 interacts with viral proteins NS2 and matrix (M), an indication of further modulation of host factors in the nucleus by RSV viral proteins. Functional correlates of these observations are poorly understood. Based on these novel findings and to fill this knowledge gap, we propose to determine the molecular mechanisms of NS1 as a major modulator of the epigenome and host responses during RSV infection. Nuclear NS1 may also skew antiviral responses while enhancing immune evasion, thereby promoting viral pathogenesis. Our team, with complementary expertise in biochemistry/structural biology, epigenetics, transcriptional regulation, and pulmonology will define the impact of RSV NS1 on host epigenetic transcriptional control, define and characterize the molecular interactions that contribute to nucleocytoplasmic transport of NS1, and determine the impact of RSV NS2 and M protein interactions on NS1 nuclear functions. To obtain mechanistic insights and to assess the impact of these observations during viral infections, we will use an approach that integrates biochemical, structural, genetic, cellular, and virological studies in relevant cell culture models, including primary human lung derived cells. By completing these synergistic Aims, we expect to provide insights into key contributors to disease and define novel targets for antiviral and vaccine development.