Exploring the Coronavirus Exoribonuclease as an Antiviral Target

探索冠状病毒外核糖核酸酶作为抗病毒靶点

基本信息

批准号：
10238324
负责人：
SANDRA K WELLER
金额：
$ 46.37万
依托单位：
UNIVERSITY OF CONNECTICUT SCH OF MED/DNT
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-19 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10238324
关键词：
2019-nCoV 5&apos -exoribonuclease Active Sites Acute Address Antiviral Agents Asia Binding Binding Sites Biochemical Biological Biological Assay COVID-19 pandemic Catalytic Domain Cells Cessation of life China Chiroptera Collection Complex Coronavirus Coronavirus Infections Custom Defect Development Disease Outbreaks Drug Synergism Drug Targeting Drug resistance Economics Ensure Enzyme Inhibitor Drugs Enzymes Evaluation Excision Exonuclease Exoribonucleases FDA Emergency Use Authorization Family Fluorescence Future Generations Genetic Transcription Genetic study Genome Guanosine Hepatitis C virus Herpesviridae Human Impairment Lead Libraries Magnesium Mediating Methyltransferase Middle East Respiratory Syndrome Middle East Respiratory Syndrome Coronavirus Morbidity - disease rate Murine hepatitis virus Mutagenesis Mutation Nidovirales Nonstructural Protein Outcome Pathogenicity Permeability Pharmaceutical Preparations Pharmacology Phenotype Positioning Attribute Production Proteins Public Health RNA RNA Viruses RNA chemical synthesis RNA replication RNA-Directed RNA Polymerase Reading Recording of previous events Reporting Resistance Respiratory syncytial virus Ribavirin Ribonucleosides Role SARS coronavirus Saudi Arabia Set protein Severe Acute Respiratory Syndrome Structure Testing Therapeutic Time Toxic effect Vaccines Viral Viral Genome Virus Virus Replication Work Zoonoses analog antiviral nucleoside analog base betacoronavirus biodefense biophysical techniques chemical resource cofactor cytotoxicity drug development efficacy study human coronavirus improved in vivo inhibitor/antagonist lead candidate lead series magnesium ion member metallicity mortality mutant novel novel therapeutics nuclease nucleoside analog pandemic disease pathogen programs remdesivir respiratory screening small molecule small molecule inhibitor synergism viral RNA zoonotic coronavirus

项目摘要

Over the last 20 years, three major zoonotic coronavirus (CoV) infections have emerged all causing acute respiratory illness, leading to significant morbidity and mortality. SARS-CoV-1 emerged in Asia in late 2002 while Middle East Respiratory Syndrome (MERS-CoV) was first reported in Saudi Arabia in 2012. In late 2019, SARS-CoV-2 was reported in China and has now spread globally causing over 673,000 deaths in less than eight months. The currently-raging COVID-19 pandemic presents an urgent need to explore new targets and approaches. Many RNA viruses such as Hepatitis C virus (HCV) and Respiratory Syncytial virus (RSV) can be treated with ribavirin and other broad-spectrum antiviral nucleoside analogues. Ribavirin and other nucleoside analogues are misincorporated into progeny genomes by the virally encoded RNA-dependent RNA-polymerase (RdRp), resulting in lethal mutagenesis. Interestingly, ribavirin has minimal effect against SARS or MERS due to unique aspects of CoV replication. The 30kb CoV genomes are the largest of all RNA viral genomes, more than three times the typical size. All CoVs encode 16 non-structural proteins (nsps) required for the production of progeny RNA. Nsp14 contains an exoribonuclease domain (ExoN), which has been shown to ensure replication fidelity of the large genome and provide resistance to drugs like ribavirin. ExoN, a conserved 3’ to 5’ proofreading exoribonuclease, removes misincorporated ribavirin, rendering it ineffective. Active site mutants of human CoV ExoN result in severe defects in viral RNA synthesis. Thus, ExoN inhibitors are expected to be effective anti- coronavirus agents either as monotherapy or in synergistic combination with nucleoside analogues. This proposal aims to discover first-in-class ExoN inhibitors for further drug development. Our current program is focused on developing broad-spectrum small molecule inhibitors of essential viral exonucleases as antiviral drugs. These exonucleases, like CoV ExoN, possess an acidic active site containing dual magnesium ions that coordinate substrate binding and catalyze bond cleavage. This ExoN key structural motif presents an excellent opportunity to expand our antiviral program to CoVs. We have synthesized hundreds of herpesvirus exonuclease inhibitors tailored to the bi-metallic binding site, which will be evaluated for activity against bacterially expressed ExoN. We propose that inhibitors of ExoN proof-reading activity would exert strong antiviral effects as single agents and would powerfully synergize with ribonucleoside analogs such as ribavirin and remdesivir. Key outcomes of the work would be (1) establishing the druggability of the active site of ExoN for small molecule inhibitors, (2) determining the antiviral activity produced by direct ExoN inhibition, (3) evaluating the potential synergism between ExoN inhibitors and nucleoside analogs and (4) identifying lead candidates for follow on in vivo drug development efforts.

在过去的20年中，出现了三个主要的人畜共努性冠状病毒（COV）感染所有引起急性呼吸道疾病，导致明显的发病率和死亡率。 SARS-COV-1于2002年底在亚洲出现尽管中东呼吸综合症（MERS-COV）于2012年首次在沙特阿拉伯报道。2019年底，据报道，SARS-COV-2在中国据报，现在在全球范围内传播，造成超过673,000人死亡不到八人月份。目前统治的COVID-19大流行迫切需要探索新的目标和方法。许多RNA病毒，例如丙型肝炎病毒（HCV）和呼吸道综合病毒（RSV）可以是用利巴韦林和其他广谱抗病毒核核苷类似物处理。利巴韦林和其他核核苷类似物被病毒编码的RNA依赖性RNA - 聚合酶错误地掺入进度基因组中（RDRP），导致致命诱变。有趣的是，利巴韦林对SARS或MER的影响很小 COV复制的独特方面。 30KB COV基因组是所有RNA病毒基因组中最大的，超过典型尺寸的三倍。所有COV编码生产所需的16种非结构性蛋白质（NSP）后代RNA。 NSP14包含一个Exoriboneclease域（外显子），已证明可以确保复制大基因组的保真度，并对利巴韦林等药物提供抗性。外显子，保守的3'至5'校对驱虫核酸酶消除了不合格的利巴韦林，使其无效。人类COV的活跃位点突变体外显子导致病毒RNA合成严重缺陷。那是外显子抑制剂有效的抗冠状病毒药物是单一疗法或与核外侧类似物的协同组合。这提案旨在发现一流的外显子抑制剂以进一步开发药物。我们当前的程序的重点是开发必需病毒的广谱小分子抑制剂外核作为抗病毒药物。这些外核酸酶，例如COV外显子，都有一个酸性活性位点，其中包含双重镁离子，该离子是协调底物结合并催化键裂解的。这个外显子键结构主题为将我们的抗病毒计划扩展到COV提供了一个绝佳的机会。我们已经合成了数百个针对双金属结合位点量身定制的疱疹病毒外切核酸酶抑制剂的抑制剂，将评估活动针对细菌表达的外显子。我们建议，外显子校验读取活动的抑制剂将发挥强大的作用作为单个药物的抗病毒作用，将与核糖核苷类似物（如利巴韦林）有效地协同作用和remdesivir。工作的关键结果将是（1）建立外显子活跃部位的可药用对于小分子抑制剂，（2）确定直接外显子抑制产生的抗病毒活性，（3）评估外显子抑制剂和核苷类似物之间的潜在协同作用，（4）识别铅候选人关注体内药物开发工作。