ABSTRACT
Paramyxoviruses comprise several major human pathogens. Although a live-attenuated vaccine protects against measles virus (MV), a member of the paramyxovirus family, the virus remains a principal cause of worldwide mortality and accounts for approximately 21 million cases and 300,000 to 400,000 deaths annually. The development of novel antivirals that allow improved case management of severe measles and silence viral outbreaks is thus highly desirable. We have previously described the development of novel MV fusion inhibitors. The potential for preexisting or emerging resistance in the field constitutes the rationale for the identification of additional MV inhibitors with a diverse target spectrum. Here, we report the development and implementation of a cell-based assay for high-throughput screening of MV antivirals, which has yielded several hit candidates. Following confirmation by secondary assays and chemical synthesis, the most potent hit was found to act as a target-specific inhibitor of MV replication with desirable drug-like properties. The compound proved highly active against multiple primary isolates of diverse MV genotypes currently circulating worldwide, showing active concentrations of 35 to 145 nM. Significantly, it does not interfere with viral entry and lacks cross-resistance with the MV fusion inhibitor class. Mechanistic characterization on a subinfection level revealed that the compound represents a first-in-class nonnucleoside inhibitor of MV RNA-dependent RNA polymerase complex activity. Singly or in combination with the fusion inhibitors, this novel compound class has high developmental potential as a potent therapeutic against MV and will likely further the mechanistic characterization of the viral polymerase complex.
摘要
副黏液病毒是几种主要的人类病原体。尽管减毒活疫苗可预防副黏液病毒家族成员之一的麻疹病毒(MV),但该病毒仍是导致全球死亡的主要原因,每年约有 2100 万例病例,造成 30 万至 40 万人死亡。因此,开发新型抗病毒药物以改善严重麻疹和沉默病毒爆发的病例管理是非常有必要的。我们以前曾介绍过新型麻疹病毒融合抑制剂的开发情况。由于该领域可能存在或正在出现耐药性,因此我们需要确定更多具有不同靶点谱的中链抑制剂。在此,我们报告了一种基于细胞的检测方法的开发和实施情况,该方法用于高通量筛选中毒性病毒抗病毒药物,目前已产生了几种候选药物。经过二次测定和化学合成的确认,我们发现最有效的候选化合物是一种靶向特异的病毒复制抑制剂,具有理想的类药物特性。事实证明,该化合物对目前全球流行的不同 MV 基因型的多个原代分离物具有很高的活性,活性浓度在 35 到 145 nM 之间。值得注意的是,它不会干扰病毒的进入,也不会与病毒融合抑制剂产生交叉耐药性。在亚感染水平上进行的机理分析表明,该化合物是第一类非核苷类 MV RNA 依赖性 RNA 聚合酶复合物活性抑制剂。无论是单独使用还是与融合抑制剂联合使用,这种新型化合物类别都具有很高的发展潜力,可作为抗 MV 的强效疗法,并有可能进一步推动病毒聚合酶复合物的机理研究。