Control of Viral Pathogenesis by Regulation of 2-5A Levels

通过调节 2-5A 水平控制病毒发病机制

• 批准号: 10310409
• 负责人: Robert H. Silverman
• 金额: $ 78.89万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10310409
• 关键词: A549; ADAR1; Acute; Animal Model; Antiviral Response; Apoptosis; Apoptotic; Binding; Cell Death; Cell Survival; Cells; Child; Chiroptera; Coronavirus; Data; Double-Stranded RNA; Ebola; Ebola virus; Embryo; Enzymes; Epithelial; Filovirus; Genes; Genetic Diseases; Grant; Health; Hepatitis; Human; Human Cell Line; Infection; Inflammatory; Interferons; Isoenzymes; Knock-out; L Cells; Ligase; Link; Liver; Lung; Marburgvirus; Mediating; Monitor; Mus; Mutate; Mutation; Pathogenesis; Pathogenicity; Pathology; Pathway interactions; Patients; Production; Protein Isoforms; Proteins; RNA; Recovery; Regulation; Resistance; Ribonucleases; Role; Rotavirus; Signal Transduction; System; T cell response; Testing; Therapeutic; Tissues; Viral; Viral Pathogenesis; Virulence Factors; Virus; Virus Diseases; Virus Replication; acute infection; adenosine deaminase; animal coronavirus; antagonist; cell type; cytotoxic; in vivo; inhibitor; innovation; mouse model; novel; oligoadenylate; overexpression; phosphoric diester hydrolase; prevent; pseudotoxoplasmosis syndrome; response; viral detection

Interferon (IFN) induction and signaling is an early antiviral response triggered by viral double-stranded (ds)RNA. While critical to limiting viral replication and spread, overexpression of the IFN response can be detrimental to human health. For example, Aicardi-Goutiéres syndrome (AGS) is a severe neurodevelopmental and inflammatory genetic disease, characterized by excessive IFN production and signaling induced by host self-dsRNA. Thus it is important to understand how the host regulates dsRNA pathways induced by self- dsRNA as well as viral (non self)-dsRNA. Oligoadenylate synthetase-ribonuclease L (OAS-RNase L) is a potent antiviral pathway that severely limits pathogenesis of many viruses. Upon sensing dsRNA, OASs produce 2',5'-oligoadenylates (2-5A) which activate RNase L to cleave both host and viral single-stranded RNA thereby limiting protein production, virus replication and spread, and leading to apoptotic cell death. During the last period we identified and characterized virus- and host-encoded phosphodiesterases (PDEs) as potent antagonists of RNase L activation, most notably the PDE of murine coronavirus (MHV), NS2, a liver specific virulence factor. We also identified OAS3 as the principal antiviral OAS in human cells. Moreover, we found that RNase L is the dominant dsRNA-dependent pathway leading to apoptosis in human cell lines by exogenous dsRNA or by self-dsRNA in cells ablated for expression of ADAR1, an enzyme that destabilizes dsRNA and when mutated can cause AGS. However, there is a gap in understanding how the activation of RNase L is controlled to prevent the potentially destructive effects of dsRNA while still maintaining the ability to limit viral replication and spread. In the continuation of this project, we will test the hypothesis that the host and viruses have multiple pathways to control the levels of 2-5A, its activation of RNase L and the directly antiviral as well as proapoptotic and proinflammatory effects of RNase L. We will use innovative approaches to investigate the OAS-RNase L system in three complementary species-specific systems, each with unique features. We will investigate: 1) how ADAR1 isoforms and host PDEs regulate levels of 2-5A in human cells, and determine which OAS isoforms are involved; 2) how the antiviral, apoptotic and inflammatory roles of RNase L cooperate to effect viral clearance in an MHV mouse model; and 3) how the OAS-RNase L pathway is expressed and activated in bats, and the mechanism(s) underlying antagonism of OAS-RNase L activation by filovirus VP35. Results of these studies should provide a better understanding of how host enzymes control the levels of self-dsRNA and 2-5A to limit RNase L activity in uninfected cells, while allowing activation during viral infections as well as the combined antiviral, apoptotic and proinflammatory roles of RNase L in viral clearance. These studies will allow us to identify targets that enhance host cell resistance to virus while minimizing the threat of over activation of OAS-RNase L to the host, and finally may contribute to identifying therapeutic strategies for viral diseases and for AGS patients with mutations in ADAR1.

干扰素（IFN）诱导和信号传导是由病毒双链触发的早期抗病毒反应 （DS）RNA。虽然对于限制病毒复制和扩散至关重要，但IFN响应的过表达可能是 对人类健康有害。例如，Aicardi-Goutiéres综合征（AGS）是严重的神经发育 和炎性遗传疾病，其特征是宿主引起的IFN产生和信号过多。 self-dsrna。重要的是要了解宿主如何调节自我诱导的dsRNA途径 dsRNA以及病毒（非自我）-DSRNA。少聚二苯基合成酶 - 核酸酶l（OAS-RNase L）是A 潜在的抗病毒途径严重限制了许多病毒的发病机理。感测dsRNA时，oass 产生了2'，5'-橄榄二烯基（2-5a），该基因烯基（2-5a）激活RNase L以清除宿主和病毒单链RNA 从而限制蛋白质的产生，病毒复制和扩散，并导致凋亡细胞死亡。在 上一个时期，我们确定并表征了病毒和宿主编码的磷酸二酯酶（PDES）为有效 RNase L激活的拮抗剂，最著名的是鼠冠状病毒（MHV），NS2，肝脏特异性的PDE 病毒因子。我们还确定了OAS3为人类细胞中的主要抗病毒OA。而且，我们发现 RNase L是主要的DSRNA依赖性途径，导致人类细胞系的细胞凋亡 外源性dsRNA或通过自dsRNA在烧蚀以表达Adar1的细胞中，这是一种破坏稳定稳定的酶 dsRNA及时突变会引起AG。但是，了解如何激活的差距 控制RNase L，以防止DSRNA的潜在破坏作用，同时仍保持能力 限制病毒复制并扩散。在该项目的延续中，我们将检验主机的假设 病毒有多种控制2-5a水平的途径，其RNase L的激活和 RNase L的直接抗病毒以及促凋亡和促炎作用。我们将使用创新 在三个完整规格的特定系统中研究OAS-RNASE L系统的方法，每个系统 具有独特的功能。我们将调查：1）ADAR1同工型和宿主PDE如何调节2-5A的水平 人类细胞，并确定涉及哪些OAS同工型； 2）抗病毒，凋亡和炎症如何 RNase L坐标在MHV小鼠模型中效应病毒清除率的作用； 3）OAS-RNASE如何L 途径在蝙蝠中表达和激活，OAS-RNase L的基本拮抗作用 FILOVIRUS VP35激活。这些研究的结果应该更好地了解主机 酶控制自dsRNA和2-5a的水平，以限制未感染的细胞中的RNase L活性，同时允许 病毒感染期间的激活以及抗病毒，凋亡和促炎作用的联合活化 病毒清除中的rNase l。这些研究将使我们能够识别出增强宿主细胞抗性的目标 病毒同时最大程度地降低了OAS-RNase L过度激活宿主的威胁，最后可能有助于 确定病毒疾病的治疗策略和ADAR1突变的AGS患者。