Department of Anatomy, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand.
Department of Microbiology and Immunology, Faculty of Veterinary Medicine, Kasetsart University, Bangkok 10900, Thailand.
Viruses. 2023 Sep 6;15(9):1887. doi: 10.3390/v15091887.
Foot-and-mouth disease (FMD) is a highly contagious disease in cloven-hoofed animals, caused by the foot-and-mouth disease virus (FMDV). It is endemic in Asia and Africa but spreads sporadically throughout the world, resulting in significant losses in the livestock industry. Effective anti-FMDV therapeutics could be a supportive control strategy. Herein, we utilized computer-aided, structure-based virtual screening to filter lead compounds from the National Cancer Institute (NCI) diversity and mechanical libraries using FMDV 3C protease (3C) as the target. Seven hit compounds were further examined via cell-based antiviral and intracellular protease assays, in which two compounds (NSC116640 and NSC332670) strongly inhibited FMDV, with EC50 values at the micromolar level of 2.88 µM (SI = 73.15) and 5.92 µM (SI = 11.11), respectively. These compounds could inactivate extracellular virus directly in a virucidal assay by reducing 1.00 to 2.27 log TCID50 of the viral titers in 0-60 min. In addition, the time-of-addition assay revealed that NSC116640 inhibited FMDV at the early stage of infection (0-8 h), while NSC332670 diminished virus titers when added simultaneously at infection (0 h). Both compounds showed good FMDV 3C inhibition with IC50 values of 10.85 µM (NSC116640) and 4.21 µM (NSC332670). The molecular docking of the compounds on FMDV 3C showed their specific interactions with amino acids in the catalytic triad of FMDV 3C. Both preferentially reacted with enzymes and proteases in physicochemical and ADME analysis studies. The results revealed two novel small molecules with antiviral activities against FMDV and probably related picornaviruses.
口蹄疫（FMD）是一种在偶蹄类动物中高度传染性的疾病，由口蹄疫病毒（FMDV）引起。它在亚洲和非洲流行，但在世界范围内零星传播，给畜牧业造成重大损失。有效的抗 FMDV 治疗方法可能是一种支持性的控制策略。在此，我们利用计算机辅助、基于结构的虚拟筛选，以 FMDV 3C 蛋白酶（3C）为靶点，从国家癌症研究所（NCI）多样性和机械文库中筛选出先导化合物。进一步通过基于细胞的抗病毒和细胞内蛋白酶测定法检查了 7 种命中化合物，其中两种化合物（NSC116640 和 NSC332670）强烈抑制 FMDV，EC50 值在微摩尔水平，分别为 2.88 µM（SI = 73.15）和 5.92 µM（SI = 11.11）。这些化合物可以在病毒杀伤测定中直接使细胞外病毒失活，在 0-60 分钟内将病毒滴度降低 1.00 至 2.27 对数 TCID50。此外，添加时间测定表明，NSC116640 在感染的早期阶段抑制 FMDV（0-8 小时），而 NSC332670 在感染时同时添加时降低病毒滴度。两种化合物均显示出良好的 FMDV 3C 抑制作用，IC50 值分别为 10.85 µM（NSC116640）和 4.21 µM（NSC332670）。化合物在 FMDV 3C 上的分子对接表明它们与 FMDV 3C 催化三联体中的氨基酸具有特异性相互作用。两者在理化和 ADME 分析研究中都优先与酶和蛋白酶反应。结果揭示了两种具有抗 FMDV 活性的新型小分子化合物，可能与相关的小核糖核酸病毒有关。
