State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institutegrid.38587.31 of the Chinese Academy of Agricultural Sciences, Harbin, China.
State Key Laboratory of Natural and Biomimetic Drugs, Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing, China.
J Virol. 2021 Oct 13;95(21):e0094421. doi: 10.1128/JVI.00944-21. Epub 2021 Aug 18.
Porcine deltacoronavirus (PDCoV) is a recently discovered coronavirus that poses a potential threat to the global swine industry. Although we know that aminopeptidase N (APN) is important for PDCoV replication, it is unclear whether it is the primary functional receptor, and the mechanism by which it promotes viral replication is not fully understood. Here, we systematically investigated the roles of porcine APN (pAPN) during PDCoV infection of nonsusceptible cells, including in viral attachment and internalization. Using a viral entry assay, we found that PDCoV can enter nonsusceptible cells but then fails to initiate efficient replication. pAPN and PDCoV virions clearly colocalized with the endocytotic markers RAB5, RAB7, and LAMP1, suggesting that pAPN mediates PDCoV entry by an endocytotic pathway. Most importantly, our study shows that regardless of which receptor PDCoV engages, only entry by an endocytotic route ultimately leads to efficient viral replication. This knowledge should contribute to the development of efficient antiviral treatments, which are especially useful in preventing cross-species transmission. PDCoV is a pathogen with the potential for transmission across diverse species, although the mechanism of such host-switching events (from swine to other species) is poorly understood. Here, we show that PDCoV enters nonsusceptible cells but without efficient replication. We also investigated the key role played by aminopeptidase N in mediating PDCoV entry via an endocytotic pathway. Our results demonstrate that viral entry via endocytosis is a major determinant of efficient PDCoV replication. This knowledge provides a basis for future studies of the cross-species transmissibility of PDCoV and the development of appropriate antiviral drugs.
猪德尔塔冠状病毒（PDCoV）是一种新近发现的冠状病毒，对全球养猪业构成潜在威胁。虽然我们知道氨肽酶 N（APN）对 PDCoV 复制很重要，但尚不清楚它是否是主要功能性受体，其促进病毒复制的机制也不完全清楚。在这里，我们系统地研究了猪 APN（pAPN）在 PDCoV 感染非易感细胞过程中的作用，包括在病毒附着和内化过程中的作用。我们使用病毒进入测定法发现，PDCoV 可以进入非易感细胞，但随后无法启动有效的复制。pAPN 和 PDCoV 病毒粒子与内吞作用标记物 RAB5、RAB7 和 LAMP1 明显共定位，表明 pAPN 通过内吞作用途径介导 PDCoV 进入。最重要的是，我们的研究表明，无论 PDCoV 结合哪种受体，只有通过内吞作用途径进入才能最终导致有效的病毒复制。这一知识应该有助于开发有效的抗病毒治疗方法，这在预防跨物种传播方面尤其有用。PDCoV 是一种具有跨多种物种传播潜力的病原体，尽管其宿主转换事件（从猪到其他物种）的机制尚不清楚。在这里，我们表明 PDCoV 进入非易感细胞，但没有有效的复制。我们还研究了氨肽酶 N 在介导 PDCoV 通过内吞作用途径进入细胞中所起的关键作用。我们的结果表明，通过内吞作用进入病毒是 PDCoV 有效复制的主要决定因素。这一知识为未来研究 PDCoV 的跨物种传播性和开发适当的抗病毒药物提供了基础。
