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.

过去 20 年来，出现了三种主要的人畜共患冠状病毒 (CoV) 感染，均导致急性呼吸道疾病，导致 2002 年底亚洲出现严重的发病率和死亡率。中东呼吸综合征 (MERS-CoV) 于 2012 年在沙特阿拉伯首次报道。2019 年底， SARS-CoV-2 在中国报告，现已在全球传播，在不到 8 年的时间里造成超过 673,000 人死亡当前肆虐的 COVID-19 大流行迫切需要探索新的目标和方法。许多 RNA 病毒，如丙型肝炎病毒 (HCV) 和呼吸道合胞病毒 (RSV) 都可以被用于治疗。用利巴韦林和其他广谱抗病毒核苷类似物治疗。类似物被病毒编码的RNA依赖性RNA聚合酶错误整合到后代基因组中 (RdRp)，导致隐含的致命突变，利巴韦林对 SARS 或 MERS 的作用微乎其微。冠状病毒复制的独特之处 30kb 的冠状病毒基因组是所有 RNA 病毒基因组中最大的，超过所有 CoV 均编码 16 种非结构蛋白（nsps），是典型大小的三倍。 Nsp14 含有核糖核酸外切酶结构域 (ExoN)，已被证明可以确保复制。大基因组的保真度并提供对利巴韦林（一种保守的 3' 至 5' 校对）等药物的抗性。核糖核酸外切酶，去除错误掺入的利巴韦林，使其无效。 ExoN 会导致病毒 RNA 合成的严重缺陷，因此 ExoN 抑制剂有望有效抗病毒。冠状病毒药物可以作为单一疗法或与核苷类似物协同组合。该提案旨在发现一流的 ExoN 抑制剂，用于进一步的药物开发。我们目前的计划重点是开发基本病毒的广谱小分子抑制剂核酸外切酶作为抗病毒药物。这些核酸外切酶，如 CoV ExoN，具有酸性活性位点，其中含有双镁离子协调底物结合并催化键断裂。该 ExoN 关键结构。主题提供了将我们的抗病毒计划扩展到冠状病毒的绝佳机会。我们已经合成了数百种。针对双金属结合位点定制的疱疹病毒核酸外切酶抑制剂，将对其活性进行评估我们认为 ExoN 校对活性的抑制剂会发挥强大的作用。作为单一药物具有抗病毒作用，并与核糖核苷类似物（如利巴韦林）产生强大的协同作用该工作的主要成果是 (1) 确定 ExoN 活性位点的成药性。对于小分子抑制剂，(2) 确定直接 ExoN 抑制产生的抗病毒活性，(3) 评估 ExoN 抑制剂和核苷类似物之间的潜在协同作用，以及 (4) 确定先导药物后续体内药物开发工作的候选者。