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: 9383726
• 负责人: Seungmin Hwang
• 金额: $ 39.9万
• 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/9383726
• 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; Recruitment Activity; 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; protein complex; 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.

项目摘要/摘要 阳性RNA（+RNA）基因组的病毒组成了一大批动植物病毒，许多 医学关注的人类病毒属于这组病毒。所有已知的 +RNA病毒形成并复制 在细胞质中的液泡样结构中，称为复制复合物（RC）。病毒RC由病毒制成 通过重组细胞器细胞器膜，并为良好的微环境提供了可观的微环境 复制病毒。然而，宿主免疫系统是否以及如何抵抗 这种病毒RCS。了解对病毒RC的宿主免疫防御策略可能使我们能够发展 针对 +RNA病毒的广泛适用抗病毒策略。我们最近发现干扰素 - 伽马（IFNG） 抑制在RC形成阶段的Norovirus（MNV）的复制。有趣的是，这种抗病毒活性 IFNG的依赖于涉及细胞自噬的蛋白质复合物。自噬是一种进化保守的 隔离双膜结合自噬体中的细胞质材料并提供的途径 到溶酶体降解。为了形成球状自噬体，微管相关的蛋白1-light- 链3（LC3）共轭系统至关重要。我们发现只有自噬的LC3结合系统，但是 IFNG抑制MNV RC的形成并不需要通过自噬的溶酶体降解。 有趣的是，IFNG还需要相同的LC3结合系统，但不需要溶酶体降解 含有原生物寄生虫弓形虫的胞质液泡。通过比较机制研究 在MNV和T. gondii模型中，我们发现需要LC3共轭系统才能募集IFN诱导 GTPases，与免疫相关的GTPase（IRGS）和鸟苷酸盐结合蛋白（Gbps）与MNV的RC。两个都 已知IRGS和GBP针对含有细菌，原生物或真菌的液泡的膜。 靶向膜是囊泡的，最终是液泡破裂的，导致暴露的死亡 病原体。同样，IFNG需要GTPases破坏MNV RC，因此抑制 小鼠和人类系统中MNV的复制。这是一种新颖而范式转移的抗病毒机制 IFNG的of，表明针对胞质复制不同病原体的常见效应机制 膜避难所，包括 +RNA病毒以及细菌，原生物和真菌。我们的长期目标是 利用这种抗病毒免疫防御的功能机制来利用医疗益处 RCS。该提案的总体目标是实现这一目标的下一步，是确定RC的RC如何 免疫系统检测并破坏了MNV。我们的中心假设是MNV RC被检测到 自噬途径的LC3共轭系统，然后RC的结构/功能被破坏 通过LC3共轭系统募集的IFN诱导GTPase。在 这项研究将对人类健康产生重大积极影响，因为它将提供对抗病毒的新见解 干扰素使用的机制以及潜在的病毒疾病干预措施的新治疗靶标。