Novel antiviral activity of interferon-gamma against viral replication complex

干扰素-γ针对病毒复制复合物的新型抗病毒活性

• 批准号: 9761827
• 负责人: Glenn C Randall
• 金额: $ 40.5万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-02 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9761827
• 关键词: ATG3 gene; Animals; Antiviral Agents; Antiviral Response; Autophagocytosis; Autophagosome; Bacteria; Binding Proteins; Cell membrane; Cellular Membrane; Cessation of life; Complex; Cytoplasm; Disease; Genome; Goals; Guanosine Triphosphate Phosphohydrolases; Health; Human; Immune; Immune Targeting; Immune response; Immune system; Immunity; Interferon Type II; Interferons; Intervention; Knowledge; Ligase; Light; Lysosomes; MAP1 Microtubule-Associated Protein; Mediating; Medical; Membrane; Modeling; Mus; Norovirus; Organelles; Parasites; Pathway interactions; Plants; Polymerase; Proteins; RNA; RNA Viruses; Rupture; Shelter facility; Structure; System; Testing; Therapeutic; Therapeutic Intervention; Toxoplasma gondii; Vacuole; Virus; Virus Diseases; Virus Replication; Work; antiviral immunity; base; comparative; fungus; guanylate; insight; new therapeutic target; novel; pathogen; pathogen exposure; protein complex; recruit; sensor

Project Summary/Abstract Viruses with positive-sense RNA (+RNA) genome compose a large group of plant and animal viruses, and many human viruses of medical concerns belong to this group of viruses. All known +RNA viruses form and replicate within vacuole-like structures in the cytoplasm, called replication complex (RC). Viral RC is made by viruses through reorganization of cellular organelle membranes, and it provides a favorable microenvironment for the viruses to replicate. Nevertheless, it has been obscure whether and how the host immune system counteracts such viral RCs. Understanding the host immune defense strategy against viral RC may allow us to develop broadly applicable antiviral strategies against +RNA viruses. We recently found that interferon-gamma (IFNG) inhibits the replication of murine norovirus (MNV) at the stage of RC formation. Intriguingly, this antiviral activity of IFNG depends on a protein complex involved in cellular autophagy. Autophagy is an evolutionarily conserved pathway that sequesters cytoplasmic materials in double-membrane-bound autophagosomes and delivers them to the lysosome for degradation. To form a globular autophagosome, the microtubule-associated-protein-1-light- chain-3 (LC3) conjugation system is essential. We found that only the LC3 conjugation system of autophagy, but not the lysosomal degradation through autophagy, is required for IFNG to inhibit MNV RC formation. Interestingly, IFNG also requires the same LC3 conjugation system, but not the lysosomal degradation, to disrupt a cytosolic vacuole containing a protist parasite Toxoplasma gondii. Through a comparative mechanism study of MNV and T. gondii models, we found that the LC3 conjugation system was required to recruit IFN-inducible GTPases, immunity related GTPases (IRGs) and guanylate binding proteins (GBPs), to the RC of MNV. Both IRGs and GBPs are known to be targeted to the membrane of vacuoles containing bacterium, protist, or fungus. The targeted membranes are vesiculated and eventually the vacuoles rupture, leading to the death of exposed pathogens. Similarly, the GTPases were required for IFNG to disrupt MNV RCs and consequently to inhibit the replication of MNV in both mouse and human systems. This is a novel and paradigm-shifting antiviral mechanism of IFNG, indicating a common effector mechanism against disparate pathogens replicating in cytosolic membranous shelters, including +RNA virus as well as bacterium, protist, and fungus. Our long-term goal is to harness the medical benefits based on the functional mechanism of this antiviral immune defense against viral RCs. The overall objective of this proposal, as the next step to pursue that goal, is to determine how the RC of MNV is detected and disrupted by the immune system. Our central hypothesis is that MNV RC is detected by the LC3 conjugation system of the autophagy pathway and then the structure/function of RC is disrupted by the IFN-inducible GTPases recruited via the LC3 conjugation system. The new fundamental knowledge created in this study will have significant positive impact on human health because it will provide a novel insight into antiviral mechanisms used by interferons and potentially new therapeutic targets of intervention for viral diseases.

项目概要/摘要 具有正义RNA（+RNA）基因组的病毒组成了一大类植物和动物病毒，并且许多 引起医学关注的人类病毒就属于这一组病毒。所有已知的+RNA病毒都会形成并复制 细胞质中的液泡样结构内，称为复制复合体（RC）。病毒RC是由病毒制成的 通过重组细胞器膜，为细胞提供良好的微环境。 病毒进行复制。然而，目前尚不清楚宿主免疫系统是否以及如何抵抗 这样的病毒 RC。了解针对病毒 RC 的宿主免疫防御策略可能使我们能够开发 针对+RNA病毒的广泛适用的抗病毒策略。我们最近发现干扰素-γ (IFNG) 在 RC 形成阶段抑制鼠诺如病毒 (MNV) 的复制。有趣的是，这种抗病毒活性 IFNG 的作用取决于参与细胞自噬的蛋白质复合物。自噬是进化上保守的 将细胞质物质隔离在双膜结合的自噬体中并输送它们的途径 至溶酶体降解。为了形成球状自噬体，微管相关蛋白 1-light- chain-3 (LC3) 缀合系统至关重要。我们发现自噬只有LC3缀合系统，但是 IFNG 抑制 MNV RC 形成所需的不是通过自噬的溶酶体降解。 有趣的是，IFNG 也需要相同的 LC3 缀合系统，但不需要溶酶体降解来破坏 含有原生寄生虫弓形虫的胞质液泡。通过比较机制研究 在 MNV 和弓形虫模型中，我们发现 LC3 接合系统需要招募 IFN 诱导型 GTP 酶、免疫相关 GTP 酶 (IRG) 和鸟苷酸结合蛋白 (GBP) 与 MNV 的 RC 相关。两个都 已知 IRG 和 GBP 靶向含有细菌、原生生物或真菌的液泡膜。 目标膜形成囊泡，最终液泡破裂，导致暴露的死亡 病原体。同样，IFNG 需要 GTPases 来破坏 MNV RC，从而抑制 MNV 在小鼠和人类系统中的复制。这是一种新颖且颠覆性的抗病毒机制 IFNG，表明针对在细胞质中复制的不同病原体的共同效应机制 膜质庇护所，包括+RNA病毒以及细菌、原生生物和真菌。我们的长期目标是 利用这种抗病毒免疫防御功能机制的医疗效益 RC。作为实现该目标的下一步，该提案的总体目标是确定 RC 如何 MNV 被免疫系统检测并破坏。我们的中心假设是 MNV RC 是通过以下方式检测到的 自噬途径的 LC3 接合系统，然后 RC 的结构/功能被破坏 通过 LC3 缀合系统招募 IFN 诱导型 GTP 酶。新的基础知识创造于 这项研究将对人类健康产生重大积极影响，因为它将提供抗病毒药物的新见解 干扰素使用的机制和干预病毒性疾病的潜在新治疗靶点。