Institute of Preventive Veterinary Medicine and Key Laboratory of Animal Virology of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China.
Institute of Preventive Veterinary Medicine and Key Laboratory of Animal Virology of Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou, Zhejiang, China
J Virol. 2018 May 29;92(12). doi: 10.1128/JVI.00318-18. Print 2018 Jun 15.
Identification of cellular receptors used by coronavirus (CoV) entry into the host cells is critical to an understanding of pathogenesis and to development of intervention strategies. The fourth CoV genus, , evolutionarily related to the , has just been defined recently. In the current study, we demonstrate that porcine aminopeptidase N (pAPN) acts as a cross-genus CoV functional receptor for both enteropathogenic porcine deltacoronovirus (PDCoV) and alphacoronovirus (AlphaCoV) (transmissible gastroenteritis virus [TGEV]) based upon three lines of evidence. First, the soluble S1 protein of PDCoV bound to the surface of target porcine cell lines known to express pAPN as efficiently as TGEV-S1, which could be blocked by soluble pAPN pretreatment. Second, both PDCoV-S1 and TGEV-S1 physically recognized and interacted with pAPN by coimmunoprecipitation in pAPN cDNA-transfected cells and by dot blot hybridization assay. Finally, exogenous expression of pAPN in refractory cells conferred susceptibility to PDCoV-S1 binding and to PDCoV entry and productive infection. PDCoV-S1 appeared to have a lower pAPN-binding affinity and likely consequent lower infection efficiency in pAPN-expressing refractory cells than TGEV-S1, suggesting that there may be differences between these two viruses in the virus-binding regions in pAPN. This study paves the way for dissecting the molecular mechanisms of PDCoV-host interactions and pathogenesis as well as facilitates future vaccine development and intervention strategies against PDCoV infection. The emergence of new human and animal coronaviruses is believed to have occurred through interspecies transmission that is mainly mediated by a species-specific receptor of the host. Among the four genera of the , a couple of functional receptors for the representative members in the genera and have been identified, whereas receptors for and , which are believed to originate from birds, are still unknown. Porcine coronaviruses, including the newly discovered porcine deltacoronavirus (PDCoV) associated with diarrhea in newborn piglets, have posed a serious threat to the pork industry in Asia and North America. Here, we report that PDCoV employs the alphacoronavirus TGEV functional receptor porcine aminopeptidase N (pAPN) for cellular entry, demonstrating the usage of pAPN as a cross-genus CoV functional receptor. The identification of the PDCoV receptor provides another example of the expanded host range of CoV and paves the way for further investigation of PDCoV-host interaction and pathogenesis.
冠状病毒（CoV）进入宿主细胞所使用的细胞受体的鉴定对于理解发病机制和开发干预策略至关重要。第四种冠状病毒属，与 进化上相关，最近才被定义。在本研究中，我们基于三条证据表明，猪氨肽酶 N（pAPN）是一种跨属冠状病毒功能受体，可用于肠致病性猪德尔塔冠状病毒（PDCoV）和甲型冠状病毒（AlphaCoV）（传染性胃肠炎病毒[TGEV]）。首先，PDCoV 的可溶性 S1 蛋白与已知表达 pAPN 的靶猪细胞系表面有效结合，与 TGEV-S1 相当，可通过可溶性 pAPN 预处理阻断。其次，PDCoV-S1 和 TGEV-S1 均可通过共免疫沉淀在 pAPN cDNA 转染细胞中以及斑点杂交分析物理识别和相互作用 pAPN。最后，在抗性细胞中外源表达 pAPN 赋予了 PDCoV-S1 结合以及 PDCoV 进入和有效感染的易感性。PDCoV-S1 似乎在表达 pAPN 的抗性细胞中具有较低的 pAPN 结合亲和力和可能较低的感染效率，这表明这两种病毒在 pAPN 中的病毒结合区可能存在差异。这项研究为剖析 PDCoV 与宿主相互作用和发病机制奠定了基础，并促进了未来针对 PDCoV 感染的疫苗开发和干预策略。新的人类和动物冠状病毒的出现被认为是通过种间传播发生的，主要由宿主的特定物种受体介导。在 科的四个属中，已经确定了代表属和 的一些功能受体，而代表属和 的受体仍未知，这些属被认为起源于鸟类。猪冠状病毒，包括与新生仔猪腹泻相关的新发现的猪德尔塔冠状病毒（PDCoV），对亚洲和北美的养猪业构成了严重威胁。在这里，我们报告 PDCoV 使用甲型冠状病毒 TGEV 功能性受体猪氨肽酶 N（pAPN）进行细胞进入，证明了 pAPN 作为跨属冠状病毒功能受体的使用。PDCoV 受体的鉴定提供了另一个 CoV 宿主范围扩大的例子，并为进一步研究 PDCoV 与宿主的相互作用和发病机制奠定了基础。
