Bi-substrate Inhibitors of SARS-CoV-2 Nsp14 Methyltransferase

摘要 严重急性呼吸综合征冠状病毒-2(SARS-CoV-2)，当前大流行的病原体 2019年冠状病毒病(新冠肺炎)的爆发，构成了现代史上前所未有的全球健康威胁。 虽然疫苗、抗体和抗病毒药物的批准为结束这一局面带来了希望 毁灭性的大流行、最近的出现和更具传染性的变种的迅速传播需要重新努力 开发有效的治疗方法来对抗SARS-CoV-2感染。在SARS-CoV-2中，RNA 5‘-帽结构是 甲基化以确保病毒翻译/复制并逃避宿主免疫监视。我们打算发现 鸟嘌呤N7-甲基转移酶(N7-MTase，Nsp14)的选择性抑制剂，因为Nsp14的活性部位 MTase是唯一受限制的，而人类RNA封顶的MTase是过度开放的。此外，受限制的 Nsp14 MTase活性部位的性质使我们能够设计双底物抑制剂。我们的初步努力已经 导致了一种纳米分子抑制剂，显示出良好的抗SARS-CoV-2活性，并且没有明显的细胞毒性。在这 应用，我们将进行先导优化，以提高我们的效力，选择性和类药物的性质 Nsp14 MTase抑制剂，旨在识别MTase抑制剂，用于未来的动物概念验证研究 SARS-CoV-2感染模型。为了实现这一目标，我们提出了以下具体目标：具体目标 1.设计合成SARS-CoV-2 Nsp14 MTase抑制剂并进行生化和抗病毒活性评价 分析方法；特定目的2.评估选定的SARS-CoV-2 Nsp14 MTase抑制剂的理化和生物化学特性 体外吸收、分布、代谢、排泄和毒性(ADMET)特性； 测定晚期SARS-CoV-2 Nsp14 MTase抑制剂的体内药代动力学(PK)参数。我们 预计拟议的研究将对开发SARS-CoV-2 NSP14 MTase的努力做出重大贡献 作为新冠肺炎疗法的抑制剂。

ABSTRACT Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of the current pandemic of coronavirus disease 2019 (COVID-19), has posed an unprecedented global health threat in modern history. While the approvals of vaccines, antibodies, and antiviral drug remdesivir have offered hope to end this devastating pandemic, recent emergence and rapid spread of more infectious variants calls for renewed efforts to develop effective therapies to combat SARS-CoV-2 infection. In SARS-CoV-2, the RNA 5′-cap structure is methylated to ensure viral translation/replication and to evade host immune surveillance. We propose to discover selective inhibitors of guanine N7-methyltransferase (N7-MTase, Nsp14) because the active site of Nsp14 MTase is uniquely constricted while human RNA capping MTases are overly open. Furthermore, the constricted nature of the Nsp14 MTase active site has allowed us to design bi-substrate inhibitors. Our preliminary effort has led to a nanomolar inhibitor that shows excellent anti-SARS-CoV-2 activity and no significant cytotoxicity. In this application, we will perform lead optimization to improve the potency, selectivity and drug-like properties of our Nsp14 MTase inhibitors, aiming to identify MTase inhibitors for use in future proof-of-concept studies in animal models of SARS-CoV-2 infection. To accomplish the goal, we propose the following specific aims: Specific Aim 1. Design and synthesize SARS-CoV-2 Nsp14 MTase inhibitors and evaluate them in biochemical and antiviral assays; Specific Aim 2. Assess selected SARS-CoV-2 Nsp14 MTase inhibitors for their physiochemical and in vitro absorption, distribution, metabolism, excretion and toxicity (ADMET) properties; and Specific Aim 3. Determine in vivo pharmacokinetics (PK) parameters of advanced SARS-CoV-2 Nsp14 MTase inhibitors. We expect that the proposed research will significantly contribute to efforts in developing SARS-CoV-2 Nsp14 MTase inhibitors as COVID-19 therapeutics.