Human noroviruses (HuNoVs) are the most common cause of viral gastroenteritis resulting in ~219,000 deaths annually and a societal cost of ~USD60 billion. There are no antivirals or vaccines available to treat and/or prevent HuNoV. In this study, we performed a large-scale phenotypical antiviral screening using the mouse norovirus (MNV), which included ~1000 drug-like small molecules from the Drug Design and Synthesis Centre (Sapienza University, Rome). Compound 3-((3,5-dimethylphenyl)sulfonyl)-5-chloroindole-N-(phenylmethanol-4-yl)-2.carboxamide (compound 1) was identified as an inhibitor of MNV replication with an EC50 of 0.5 ± 0.1 µM. A series of 10 analogs were synthesized of which compound 6 showed an improved potency/selectivity (EC50 0.2 ± 0.1 µM) against MNV; good activity was also observed against the HuNoV GI replicon (EC50 1.2 ± 0.6 µM). Time-of-drug-addition studies revealed that analog 6 acts at a time point that coincides with the onset of viral RNA replication. After six months of selective pressure, two compound 6res variants were independently selected, both harboring one mutation in VPg and three mutations in the RdRp. After reverse engineering S131T and Y154F as single mutations into the MNV backbone, we did not find a markedly compound 6res phenotype. In this study, we present a class of novel norovirus inhibitors with a high barrier to resistance and in vitro antiviral activity.
人类诺如病毒(HuNoVs)是引起病毒性胃肠炎最常见的原因,每年导致约219,000人死亡,社会成本约为600亿美元。目前没有可用于治疗和/或预防HuNoV的抗病毒药物或疫苗。在本研究中,我们使用小鼠诺如病毒(MNV)进行了大规模的表型抗病毒筛选,包括来自罗马大学Sapienza药物设计和合成中心的约1000种药物类小分子。鉴定出化合物3-((3,5-二甲基苯基)磺酰基)-5-氯吲哚-N-(苯甲醇-4-基)-2.羧酰胺(化合物1)作为MNV复制抑制剂,其EC50为0.5±0.1微米。合成了一系列的10个类似物,其中化合物6对MNV显示出改进的效力/选择性(EC50 0.2±0.1微米),对HuNoV GI复制体也观察到良好的活性(EC50 1.2±0.6微米)。药物添加时间研究表明,类似物6在病毒RNA复制开始时起作用。经过六个月的选择性压力后,独立选择了两个化合物6res变体,均含有VPg中的一个突变和RdRp中的三个突变。将S131T和Y154F作为单个突变逆向工程到MNV骨架中后,我们没有发现显着的化合物6res表型。本研究提出了一类具有高抗性阈值和体外抗病毒活性的新型诺如病毒抑制剂。