Project 1 - Virus-Host Interactions in Gammaherpesvirus Pathogenesis

人类伽马疱疹病毒(GHV)、爱泼斯坦-巴尔病毒(EBV)和卡波西肉瘤相关疱疹病毒(KSHV)是DNA肿瘤病毒，可建立宿主淋巴细胞和其他细胞类型的终身慢性感染。通过病毒基因产物的表达改变正常的细胞信号通路和对抗宿主免疫反应，GHV将长期感染的宿主置于多种恶性肿瘤的风险中。由于这与定义微生物毒力因子对宿主炎症和免疫反应的影响的Cobre主题有关，本项目中描述的实验的总体目标是更好地定义GHV中和固有宿主防御机制的机制，以便成功地定植宿主。这一目标的核心是利用小鼠伽马疱疹病毒68(MHV68)，这是一种自然发生的啮齿动物病原体，在基因上与EBV和KSHV有关，并概括了人类GHV感染的关键方面，作为一种易处理的小动物模型来确定体内病毒与宿主的相互作用。扩展我们已发表的和初步的数据，目前的建议特别试图了解MHV68潜伏期相关核抗原(MLANA)的功能，这是一种假定的病毒转录抑制蛋白，是抗病毒转录途径或由干扰素α/β(IFN-I)信号激活的细胞免疫反应的关键调节器，否则将限制GHV感染。这项工作将在三个完整而独立的特定目标下完成：(1)明确干扰素-L介导的GHV感染在粘膜屏障处的控制；(2)阐明mLANA介导的转录调控在MHV68发病中的作用；(3)确定mLANA-干扰素调节因子3(IRF-3)在MHV68感染中的相互作用。这些实验具有广泛的意义，因为它解决了我们对GHV发病机制理解中的两个关键差距：病毒疾病决定因素在GHV感染成功中的作用，以及GHV与宿主先天性免疫反应途径的相互作用。此外，通过促进对宿主免疫反应本质的理解，这对所有传染病来说都是至关重要的，拟议的实验也可能与由不同和无关的细胞内病原体引起的疾病相关。

The human gammaherpesviruses (GHVs) Epstein-Barr virus (EBV) and Kaposi sarcoma-associated herpesvirus (KSHV) are DNA tumor viruses that establish lifelong chronic infections of host lymphocytes and other cell types. Through the expression of viral gene products that alter normal cellular signaling pathways and counteract host immune responses, GHVs place the chronically infected host at risk for numerous malignancies. As it relates to the COBRE theme of defining the impact of microbial virulence factors on host inflammatory and immune responses, the overall objective of experiments described in this project is to better define mechanisms by which GHVs counteract innate host defense mechanisms in order to successfully colonize a host. Central to this objective is the utilization of murine gammaherpesvirus-68 (MHV68), a naturally occurring rodent pathogen that is genetically related to EBV and KSHV and recapitulates key aspects of human GHV infection as a tractable small-animal model to define the virus-host interaction in vivo. Extending our published and preliminary data, the current proposal specifically seeks to understand functions of the MHV68 latency-associated nuclear antigen (mLANA), a putative viral transcriptional repressor protein, as a critical modulator of antiviral transcriptional pathways or cellular immune responses activated by interferon alpha/Beta (IFN-I) signaling that would otherwise restrict GHV infection. This work will be accomplished in three integrated but independent specific aims: (1) define IFN-l-mediated control of GHV infection at mucosal barriers, (2) elucidate roles for mLANA-mediated transcriptional control in MHV68 pathogenesis, and (3) define mLANA-interferon regulatory factor 3 (IRF-3) interactions in MHV68 infection. The proposed experiments hold broad significance by addressing two critical gaps in our understanding of GHV pathogenesis: the functions of viral disease determinants in the success of GHV infection and the interactions of GHV with host innate immune response pathways. Moreover, by advancing understanding of the nature of host immune responses, which is fundamentally important to all infectious diseases, the proposed experiments may also hold relevance for diseases caused by diverse and unrelated intracellular pathogens.