Laboratory of Molecular RNA Virology and Antiviral Strategies, Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
Bioinformatics Institute, Agency for Science, Technology and Research (A∗STAR), 30 Biopolis Street, Matrix #07-01, 138671, Singapore.
EBioMedicine. 2024 Sep;107:105277. doi: 10.1016/j.ebiom.2024.105277. Epub 2024 Sep 2.
Global cyclical outbreaks of human enterovirus infections has positioned human enterovirus A71 (EV-A71) as a neurotropic virus of clinical importance. However, there remains a scarcity of internationally approved antivirals and vaccines.
In pursuit of repurposing drugs for combating human enteroviruses, we employed a comprehensive pharmacophore- and molecular docking-based virtual screen targeting EV-A71 capsid protein VP1-4, 3C protease, and 3D polymerase proteins. Among 15 shortlisted ligand candidates, we dissected the inhibitory mechanism of Tanomastat in cell-based studies and evaluated its in vivo efficacy in an EV-A71-infected murine model.
We demonstrated that Tanomastat exerts dose-dependent inhibition on EV-A71 replication, with comparable efficacy profiles in enterovirus species A, B, C, and D in vitro. Time-course studies suggested that Tanomastat predominantly disrupts early process(es) of the EV-A71 replication cycle. Mechanistically, live virus particle tracking and docking predictions revealed that Tanomastat specifically impedes viral capsid dissociation, potentially via VP1 hydrophobic pocket binding. Bypassing its inhibition on entry stages, we utilized EV-A71 replication-competent, 3D replication-defective, and bicistronic IRES reporter replicons to show that Tanomastat also inhibits viral RNA replication, but not viral IRES translation. We further showed that orally administered Tanomastat achieved 85% protective therapeutic effect and alleviated clinical symptoms in EV-A71-infected neonatal mice.
Our study establishes Tanomastat as a broad-spectrum anti-enterovirus candidate with promising pre-clinical efficacy, warranting further testing for potential therapeutic application.
MOE Tier 2 grants (MOE-T2EP30221-0005, R571-000-068-592, R571-000-076-515, R571-000-074-733) and A∗STARBiomedical Research Council (BMRC).
全球范围内人类肠道病毒感染呈周期性爆发，人类肠道病毒 A71（EV-A71）已成为一种具有临床重要性的神经嗜性病毒。然而，目前仍缺乏国际认可的抗病毒药物和疫苗。
为了寻找对抗人类肠道病毒的药物再利用，我们采用了一种综合的基于药效团和分子对接的虚拟筛选方法，针对 EV-A71 衣壳蛋白 VP1-4、3C 蛋白酶和 3D 聚合酶蛋白。在 15 个入围的配体候选物中，我们在细胞水平研究中剖析了 Tanomastat 的抑制机制，并在 EV-A71 感染的小鼠模型中评估了其体内疗效。
我们证明 Tanomastat 对 EV-A71 复制具有剂量依赖性抑制作用，在体外对肠道病毒 A、B、C 和 D 具有相似的疗效。时程研究表明，Tano-mastat 主要破坏 EV-A71 复制周期的早期过程。从机制上讲，活病毒粒子追踪和对接预测表明，Tano-mastat 特异性地阻碍病毒衣壳的解离，可能通过 VP1 疏水性口袋结合。绕过其对进入阶段的抑制作用，我们利用 EV-A71 复制能力、3D 复制缺陷和双顺反子 IRES 报告复制子，表明 Tanomastat 还抑制病毒 RNA 复制，但不抑制病毒 IRES 翻译。我们进一步表明，口服给予 Tanomastat 可在 EV-A71 感染的新生小鼠中实现 85%的保护治疗效果并缓解临床症状。
我们的研究确立了 Tanomastat 作为一种具有广阔应用前景的广谱抗肠道病毒候选药物，具有良好的临床前疗效，值得进一步测试，以确定其潜在的治疗应用价值。
MOE 二级资助计划（MOE-T2EP30221-0005、R571-000-068-592、R571-000-076-515、R571-000-074-733）和 A*STAR 生物医学研究理事会（BMRC）。
