The porcine epidemic diarrhea virus (PEDV) is an Alphacoronavirus (α-CoV) that causes high mortality in infected piglets, resulting in serious economic losses in the farming industry. Hypericin is a dianthrone compound that has been shown as an antiviral activity on several viruses. Here, we first evaluated the antiviral effect of hypericin in PEDV and found the viral replication and egression were significantly reduced with hypericin post-treatment. As hypericin has been shown in SARS-CoV-2 that it is bound to viral 3CLpro, we thus established a molecular docking between hypericin and PEDV 3CLpro using different software and found hypericin bound to 3CLpro through two pockets. These binding pockets were further verified by another docking between hypericin and PEDV 3CLpro pocket mutants, and the fluorescence resonance energy transfer (FRET) assay confirmed that hypericin inhibits the PEDV 3CLpro activity. Moreover, the alignments of α-CoV 3CLpro sequences or crystal structure revealed that the pockets mediating hypericin and PEDV 3CLpro binding were highly conserved, especially in transmissible gastroenteritis virus (TGEV). We then validated the anti-TGEV effect of hypericin through viral replication and egression. Overall, our results push forward that hypericin was for the first time shown to have an inhibitory effect on PEDV and TGEV by targeting 3CLpro, and it deserves further attention as not only a pan-anti-α-CoV compound but potentially also as a compound of other coronaviral infections.

中文翻译：

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金丝桃素通过靶向 3CL 蛋白酶抑制 α-冠状病毒复制

猪流行性腹泻病毒 (PEDV) 是一种α冠状病毒(α-CoV) 导致感染仔猪的高死亡率，从而导致养殖业的严重经济损失。金丝桃素是一种二蒽酮化合物，已显示出对几种病毒的抗病毒活性。在这里，我们首先评估了金丝桃素在 PEDV 中的抗病毒作用，发现金丝桃素后处理显着减少了病毒的复制和流出。由于金丝桃素在 SARS-CoV-2 中已被证明与病毒 3CLpro 结合，因此我们使用不同的软件在金丝桃素和 PEDV 3CLpro 之间建立了分子对接，并发现金丝桃素通过两个口袋与 3CLpro 结合。这些结合口袋通过金丝桃素和 PEDV 3CLpro 口袋突变体之间的另一次对接进一步验证，荧光共振能量转移 (FRET) 测定证实金丝桃素抑制 PEDV 3CLpro 活性。此外，α-CoV 3CLpro 序列或晶体结构的比对表明，介导金丝桃素和 PEDV 3CLpro 结合的口袋是高度保守的，尤其是在传染性胃肠炎病毒（TGEV）中。然后，我们通过病毒复制和传出验证了金丝桃素的抗 TGEV 作用。总的来说，我们的结果推动了金丝桃素首次通过靶向 3CLpro 对 PEDV 和 TGEV 产生抑制作用，它不仅是一种泛抗 α-CoV 化合物，而且还可能作为一种化合物，值得进一步关注其他冠状病毒感染。然后，我们通过病毒复制和传出验证了金丝桃素的抗 TGEV 作用。总的来说，我们的结果推动了金丝桃素首次通过靶向 3CLpro 对 PEDV 和 TGEV 产生抑制作用，它不仅是一种泛抗 α-CoV 化合物，而且还可能作为一种化合物，值得进一步关注其他冠状病毒感染。然后，我们通过病毒复制和传出验证了金丝桃素的抗 TGEV 作用。总的来说，我们的结果推动了金丝桃素首次通过靶向 3CLpro 对 PEDV 和 TGEV 产生抑制作用，它不仅是一种泛抗 α-CoV 化合物，而且还可能作为一种化合物，值得进一步关注其他冠状病毒感染。