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) 诱导和信号转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传播至关重要，但 IFN 反应的过度表达可能会影响病毒的复制和传播。 例如，Aicardi-Goutiéres 综合征 (AGS) 是一种严重的神经发育障碍。 和炎症性遗传病，其特征是宿主诱导过量的干扰素产生和信号传导 因此，了解宿主如何调节自体 dsRNA 诱导的 dsRNA 途径非常重要。 dsRNA 以及病毒（非自身）-dsRNA 是寡腺苷酸合成酶核糖核酸酶 L (OAS-RNase L)。 有效的抗病毒途径，在检测 dsRNA、OAS 后严重限制了许多病毒的发病机制。 产生 2',5'-寡腺苷酸 (2-5A)，激活 RNase L 以裂解宿主和病毒单链 RNA 限制蛋白质产生、病毒复制和传播，并导致细胞凋亡。 上一期我们鉴定并鉴定了病毒和宿主编码的磷酸二酯酶 (PDE) 是有效的 RNase L 激活的拮抗剂，尤其是鼠冠状病毒 (MHV) 的 PDE、NS2（一种肝脏特异性药物） 我们还发现 OAS3 是人体细胞中主要的抗病毒 OAS。 RNase L 是导致人类细胞系凋亡的主要 dsRNA 依赖性途径 外源 dsRNA 或通过消除 ADAR1 表达的细胞中的自身 dsRNA，ADAR1 是一种不稳定的酶 dsRNA 突变时会导致 AGS，但是，对于如何激活 dsRNA 的理解还存在差距。 RNase L 受到控制，以防止 dsRNA 的潜在破坏性影响，同时仍保持能力 限制病毒复制和传播 在这个项目的继续中，我们将检验宿主的假设。 病毒有多种途径来控制 2-5A 的水平、其 RNase L 的激活以及 RNase L 具有直接抗病毒以及促凋亡和促炎作用。我们将使用创新的 方法在三个互补的物种特异性系统中研究 OAS-RNase L 系统，每个系统 我们将研究：1) ADAR1 同种型和宿主 PDE 如何调节 2-5A 的水平。 人类细胞，并确定哪些 OAS 亚型参与其中；2) 如何发挥抗病毒、细胞凋亡和炎症作用； RNase L 的作用在 MHV 小鼠模型中协同影响病毒清除；3) OAS-RNase L 如何发挥作用 途径在蝙蝠中表达和激活，以及 OAS-RNase L 拮抗作用的机制 这些研究结果应该有助于更好地了解宿主如何激活。 酶控制自身 dsRNA 和 2-5A 的水平，以限制未感染细胞中 RNase L 的活性，同时允许 病毒感染期间的激活以及抗病毒、细胞凋亡和促炎作用的组合 这些研究将使我们能够确定增强宿主细胞抵抗力的靶标。 病毒，同时最大限度地减少 OAS-RNase L 过度激活对宿主的威胁，最终可能有助于 病毒性疾病的治疗策略以及 ADAR1 突变 AGS 患者的识别。