Mechanisms mediating immune response upon sensing of nuclear viral DNA

感测核病毒 DNA 介导免疫反应的机制

• 批准号: 9027921
• 负责人: Ileana M. Cristea
• 金额: $ 31.87万
• 依托单位: PRINCETON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-15 至 2019-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9027921
• 关键词: Acute Promyelocytic Leukemia; Address; Antiviral Agents; Antiviral Response; Antiviral Therapy; Belief; Binding; Biochemistry; Biological Assay; Cell Nucleus; Cells; Cytomegalovirus; Cytomegalovirus Infections; Cytoplasm; DNA; DNA Viruses; Development; Drug Design; Drug Targeting; Endoplasmic Reticulum; Equilibrium; Event; Fluorescent in Situ Hybridization; Hand; Health; Herpesviridae; Herpesvirus 1; Homo; Human; Hybrids; Immune; Immune System Diseases; Immune response; Immune system; Immunity; Infection; Interferons; Lead; Life; Light; Maintenance; Malignant Neoplasms; Mammalian Cell; Mediating; Methods; Microbe; Microscopy; Molecular Biology; Morbidity - disease rate; Nuclear; Nuclear Export; Pathway interactions; Pilot Projects; Property; Proteins; Proteomics; RNA Viruses; Recruitment Activity; Regulation; Replication Origin; Research; Role; Series; Signal Transduction; Staging; System; Testing; Ubiquitin; Viral Proteins; Virus; Work; adapter protein; base; cellular imaging; cytokine; interdisciplinary approach; marenostrin; mortality; novel; novel therapeutics; optogenetics; pathogen; public health relevance; sensor; small hairpin RNA; transmission process; viral DNA

 DESCRIPTION (provided by applicant): The ability of the mammalian immune system to recognize pathogenic DNA, such as DNA from viruses, is essential for the onset of intrinsic and innate immune responses. This recognition is accomplished by specialized cellular proteins called DNA sensors, which bind foreign DNA and elicit the secretion of cytokines to alert neighboring cells and inhibit the spread of infection. Until recently, the sensing of foreign DNA was thought to occur only in subcellular compartments normally devoid of DNA. However, this long-standing belief failed to explain how the cell detects nuclear-replicating DNA viruses. Our lab's recent characterization of the first identified nuclear DNA sensor, IFI16, has helped to firmly establish the concept of nuclear sensing. We demonstrated that IFI16 functions to sense herpesviruses, including the important pathogens, human cytomegalovirus (HCMV) and herpes simplex virus type 1 (HSV-1) (Li et al. PNAS 2012; Li et al. Cell Host Microbe 2013). The discovery that sensing can occur in the nucleus opens a new direction for research in immunity that will increase our understanding of how balanced immune responses work to maintain a healthy system and how their misregulation leads to immune disorders, cancers, and virus-induced morbidity and mortality. However, a fundamental question that has yet to be answered is how the immune signal is propagated from the nucleus. We found that, while IFI16 remains nuclear during the early stages of HCMV and HSV-1 infections, the IFI16-mediated induction of antiviral cytokines requires the endoplasmic reticulum adapter protein STING-a hub for DNA sensing pathways. The requirements for eliciting an immune response from the nucleus and the mechanism of immune signal propagation to the cytoplasm remain elusive. Our proposal will address these important questions. First, we will characterize the mechanism by which IFI16 rapidly co-localizes with viral DNA in the nucleus. We have discovered that IFI16 is recruited to promyelocytic leukemia (PML) nuclear bodies (NBs) following infection. PML-NBs have been implicated in antiviral response and shown to localize to origins of replication of herpesviruses. Using a multidisciplinary approach, we will test our hypothesis that PML-NBs function as interaction centers where IFI16 concentrates its binding of viral DNA, setting the stage for immune signal initiation. Second, we will use molecular biology, biochemistry, optogenetics, and live cell imaging to define the IFI16 properties required for initiating nuclear immune signals. We hypothesize that signal initiation requires IFI16 oligomerization via its pyrin domain at PML-NBs. Third, we will determine how the nucleus-derived immune signal is transmitted to the cytoplasm. We discovered that IFI16 interacts with interferon-inducible IFIT proteins, which shuttle to the nucleus upon infection. We propose mechanistic studies to test our hypothesis that IFI16-dependent immune signaling is relayed by such interactions to the STING hub. Collectively, our results will characterize a newly discovered aspect of immunity, nuclear sensing, by defining the fundamental mechanisms required for immune signal propagation.

 描述（由适用提供）：哺乳动物免疫系统识别病毒DNA的能力，例如病毒的DNA，对于内在和先天免疫调查的发作至关重要。这种识别是通过称为DNA传感器的专用细胞蛋白来实现的，该蛋白结合外源DNA并引起细胞因子的分泌以提醒相邻细胞并抑制感染的扩散。直到最近，外国DNA的敏感性仅发生在通常没有DNA的亚细胞室中。然而，这种长期以来的人们认为无法解释细胞如何检测核重复的DNA病毒。我们实验室最近对第一个识别的核DNA传感器IFI16的表征有助于首先建立核传感器的概念。我们证明了IFI16的功能可感知疱疹病毒，包括重要的病原体，人类巨细胞病毒（HCMV）和单纯疱疹病毒1型（HSV-1）（HSV-1）（Li等人PNAS 2012; Li等人，Li等人Cell。Cell。Cell宿主Microbe 2013）。可以在核中发生传感的发现为免疫学研究开辟了一个新的方向，这将增加我们对平衡免疫调查如何保持健康系统的理解，以及它们的正直如何导致免疫疾病，癌症和病毒诱导的发病率和死亡率。但是，尚未回答的一个基本问题是如何从核心传播免疫信号。我们发现，尽管IFI16在HCMV和HSV-1感染的早期阶段仍然保持核，但IFI16介导的抗病毒细胞因子的诱导需要内质网状网状蛋白sting-a Hub才能用于DNA感应途径。从核us引起免疫响应的要求以及对细胞质的免疫信号传播机制仍然难以捉摸。我们的建议将解决这些重要问题。首先，我们将表征IFI16在细胞核中与病毒DNA迅速共定位的机制。我们发现感染后，将IFI16招募到临床细胞性白血病（PML）核体（NBS）。 PML-NBS已在抗病毒反应中暗示，并显示为疱疹病毒复制的起源。使用多学科方法，我们将测试假设PML-NBS作为相互作用中心的假设，其中IFI16集中了其病毒DNA的结合，为免疫信号启动奠定了基础。其次，我们将使用分子生物学，生物化学，光遗传学和活细胞成像来定义启动核免疫信号所需的IFI16特性。我们 假设该信号倡议需要通过其在PML-NBS处的吡啶结构域IFI16低聚。第三，我们将确定如何将核衍生的免疫信号传播到细胞质。我们发现IFI16与可干扰诱导的IFIT蛋白相互作用，IFIT蛋白会在感染后向核US穿梭。我们提出机械研究，以检验我们的假设，即IFI16依赖性免疫信号传导通过这种相互作用与STING HUB传递。总的来说，我们的结果将通过定义免疫信号传播所需的基本机制来表征免疫史，核传感的新发现的方面。