Key Laboratory of Veterinary Biological Engineering and Technology Ministry of Agriculture, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences, Nanjing, Jiangsu, China.
Jiangsu Key Laboratory for Food Quality and Safety-State Key Laboratory Cultivation Base of Ministry of Science and Technology, Institute of Veterinary Medicine, Jiangsu Academy of Agricultural Sciences; Nanjing, Jiangsu, China.
PLoS Biol. 2023 Mar 17;21(3):e3002039. doi: 10.1371/journal.pbio.3002039. eCollection 2023 Mar.
Coronaviruses (CoVs) comprise a group of important human and animal pathogens. Despite extensive research in the past 3 years, the host innate immune defense mechanisms against CoVs remain incompletely understood, limiting the development of effective antivirals and non-antibody-based therapeutics. Here, we performed an integrated transcriptomic analysis of porcine jejunal epithelial cells infected with porcine epidemic diarrhea virus (PEDV) and identified cytidine/uridine monophosphate kinase 2 (CMPK2) as a potential host restriction factor. CMPK2 exhibited modest antiviral activity against PEDV infection in multiple cell types. CMPK2 transcription was regulated by interferon-dependent and interferon regulatory factor 1 (IRF1)-dependent pathways post-PEDV infection. We demonstrated that 3'-deoxy-3',4'-didehydro-cytidine triphosphate (ddhCTP) catalysis by Viperin, another interferon-stimulated protein, was essential for CMPK2's antiviral activity. Both the classical catalytic domain and the newly identified antiviral key domain of CMPK2 played crucial roles in this process. Together, CMPK2, viperin, and ddhCTP suppressed the replication of several other CoVs of different genera through inhibition of the RNA-dependent RNA polymerase activities. Our results revealed a previously unknown function of CMPK2 as a restriction factor for CoVs, implying that CMPK2 might be an alternative target of interfering with the viral polymerase activity.
冠状病毒（CoV）是一组重要的人类和动物病原体。尽管在过去的 3 年中进行了广泛的研究，但宿主先天免疫防御机制对 CoV 的认识仍不完全，这限制了有效抗病毒药物和非抗体治疗药物的开发。在这里，我们对感染猪流行性腹泻病毒（PEDV）的猪小肠上皮细胞进行了综合转录组分析，鉴定出胞苷/尿苷一磷酸激酶 2（CMPK2）作为一种潜在的宿主限制因子。CMPK2 在多种细胞类型中对 PEDV 感染表现出适度的抗病毒活性。CMPK2 的转录受干扰素依赖和干扰素调节因子 1（IRF1）依赖途径的调节。我们证明，另一种干扰素刺激蛋白 Viperin 的 3'-脱氧-3'，4'-二氢胞苷三磷酸（ddhCTP）催化作用对于 CMPK2 的抗病毒活性是必不可少的。CMPK2 的经典催化结构域和新鉴定的抗病毒关键结构域在这个过程中都发挥了关键作用。CMPK2、Viperin 和 ddhCTP 通过抑制 RNA 依赖性 RNA 聚合酶活性，共同抑制了几种不同属的其他 CoV 的复制。我们的研究结果揭示了 CMPK2 作为 CoV 限制因子的先前未知功能，这意味着 CMPK2 可能是干扰病毒聚合酶活性的替代靶标。
