ANTIVIRAL MECHANISMS OF 2-5A-DEPENDENT RNASE L

2-5A依赖性RNA酶L的抗病毒机制

• 批准号: 10005110
• 负责人: Robert H. Silverman
• 金额: $ 40.25万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-25 至 2022-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10005110
• 关键词: 2-5A Synthetase; ABCE1 gene; ADAR1; Antiviral Agents; Antiviral Response; Apoptotic; Autophagocytosis; Binding; Biological Assay; Caspase; Cause of Death; Cell Death; Cells; Cleaved cell; Complex; Crystallization; DNA Viruses; Double-Stranded RNA; Enhancers; Enzymes; Equilibrium; Family; Health; Host Defense; Human; Immune system; Inflammasome; Inflammation; Inflammatory; Integration Host Factors; Interferons; Knockout Mice; Knowledge; Lead; Mediating; Mus; Oncolytic viruses; Pathogenicity; Pathway interactions; Pharmaceutical Preparations; Philadelphia; Population; Protein Kinase; Protocols documentation; RNA Viruses; Ramp; Reporting; Ribonucleases; Roentgen Rays; Role; Signal Transduction; Small RNA; Structure; System; Therapeutic; Toxic effect; Vertebrates; Viral; Virus; Virus Diseases; dimer; improved; in vivo; inhibitor/antagonist; knockout gene; member; novel; oligoadenylate; pathogenic virus; phosphodiesterase V; small molecule; small molecule inhibitor; viral RNA

The 2',5'-oligoadenylate (2-5A) synthetase (OAS)-RNase L system is a robust interferon (IFN)-inducible antiviral pathway that contributes to the survival of higher vertebrates against both RNA and DNA viruses. Accordingly, viruses have acquired and evolved a multitude of mechanisms to antagonize OAS-RNase L. During the past 5 years, we established roles for RNase L in IFN signaling, inflammasome activation and autophagy. Yet there remains much to be learned about how RNase L suppresses viral infections, how viruses evade these enzymes, and how the host recovers from RNase L activation. In particular, our knowledge of how RNase L is regulated through its protein kinase-like domain, how RNase L mediates cell death from ADAR1 deficiency, how the RNase L inhibitor (ABCE1 aka RLI) functions, and how RNase L activates the NLRP3 inflammasome is still fragmentary. Therefore, the proposed continuation of this project will systematically investigate the major outstanding questions about this critically important host antiviral pathway. The unifying theme of this application concerns how RNase L function is regulated beyond its activation by 2-5A, in particular through its protein kinase-like (PKL) domain, to control viral infections and inflammation. Our findings lead to the hypothesis that the OAS-RNase L system is an integral part of the host immune system that must be tightly regulated to eliminate viruses while also limiting its harmful pro-inflammatory effects. Our specific aims are: (1) To study the impact of the RNase L PKL domain on cells and viruses we will evaluate recently identified small molecule inhibitors, enhancers and their derivatives on RNase L activity, determine the ability of the small molecules to control viral infections, and investigate effects of the RNase L inhibitors on cell death caused by ADAR1 deficiency. (2) To investigate how the ATP-binding cassette member, ABCE1 (RLI), limits RNase L activity, we will determine precisely how ABCE1 interacts with RNase L to inhibit its activity, establish how the host cells ramps up RNase L activity during viral infections by caspase-mediated cleavage of ABCE1, and determine the ability of ABCE1 to counteract cellular toxicity of double stranded RNA by inhibiting RNase L. (3) To probe the mechanism of NLRP3 inflammasome activation by RNase L, we will identify and characterize RNase L-cleaved viral RNA activators of the NLRP3 inflammasome, determine effects of the small RNA cleavage products on inflammasome activation, and determine the impact of RNase L inhibitor drugs on viral mediated inflammation in vivo. Viral infections remain a serious threat to human health worldwide. Despite viral countermeasures, the OAS-RNase L system has a major impact against many types of pathogenic viruses. These studies emphasize how central and important it is to regulate RNase L in order to mediate the balance between antiviral activity and cell death. It is believed that a better understanding of the viral and host factors that regulate RNase L activity may eventually lead to novel and improved therapeutic approaches for treating established and emerging viral infections in the human population.

2'，5'-橄榄二烯基（2-5a）合成酶（OAS） - RNase L系统是一种健壮的干扰素（IFN） - 可诱导 抗病毒途径有助于较高的脊椎动物对RNA和DNA病毒的存活。 因此，病毒已经获得并进化了多种机制来拮抗OAS-RNASEL。 在过去的5年中，我们在IFN信号传导，炎症体激活和 自噬。然而，关于RNase L如何抑制病毒感染，病毒如何抑制病毒，还有很多值得了解的了解 逃避这些酶，以及宿主如何从RNase L激活中恢复。特别是我们对如何的了解 RNase L通过其蛋白激酶样结构域调节，RNase L如何介导ADAR1的细胞死亡 缺乏症，RNase L抑制剂（ABCE1 aka RLI）的功能以及RNase L如何激活NLRP3 炎症小子仍然是碎片的。因此，该项目的拟议延续将有系统地 研究有关此至关重要的宿主抗病毒途径的主要杰出问题。统一 该应用程序的主题涉及RNase L功能如何受到2-5a激活的调节，in 特别是通过其蛋白激酶样（PKL）结构域来控制病毒感染和炎症。我们的发现 导致一个假设，即OAS-RNASE L系统是宿主免疫系统的组成部分，必须 严格调节以消除病毒，同时还限制其有害的促炎作用。我们的具体 目的是：（1）研究RNase L PKL结构域对细胞和病毒的影响，我们将最近评估 鉴定出小分子抑制剂，增强剂及其在RNase L活性上的衍生物，确定能力 用于控制病毒感染的小分子，并研究RNase L抑制剂对细胞死亡的影响 由ADAR1缺乏引起。 （2）调查ATP结合纸盒成员ABCE1（RLI）如何限制 RNase L活性，我们将确切确定ABCE1与RNase L相互作用以抑制其活性，建立 宿主细胞如何通过caspase介导的ABCE1裂解，在病毒感染过程中升高RNase L活性 并确定ABCE1通过抑制RNase L来抵消双链RNA的细胞毒性的能力。 （3）为了探测RNase L的NLRP3炎性体激活的机理，我们将识别和表征 NLRP3炎性体的RNase L-裂解的病毒RNA激活剂，确定小RNA的作用 切割产物对炎性体激活，并确定RNase L抑制剂对病毒的影响 体内介导的炎症。病毒感染仍然对全球人类健康构成严重威胁。尽管病毒 对策，OAS-RNASE L系统对许多类型的致病病毒具有重大影响。 这些研究强调调节RNase L以调节平衡是多么重要 在抗病毒活性和细胞死亡之间。人们认为对病毒和宿主因素有更好的了解 调节RNase L活性最终可能导致新颖和改进的治疗方法 在人群中建立和新兴的病毒感染。