title: Tight Junction Protein Occludin Is a Porcine Epidemic Diarrhea Virus Entry Factor.
abstract: Porcine epidemic diarrhea virus (PEDV), the causative agent of porcine epidemic diarrhea, has caused huge economic losses in pig-producing countries. Although PEDV was long believed to replicate in the intestinal epithelium by using aminopeptidase N as a receptor, the mechanisms of PEDV infection are not fully characterized. In this study, we found that PEDV infection of epithelial cells results in disruption of the tight junctional distribution of occludin to its intracellular location. Overexpression of occludin in target cells makes them more susceptible to PEDV infection, whereas ablation of occludin expression by use of small interfering RNA (siRNA) in target cells significantly reduces their susceptibility to virus infection. However, the results observed with occludin siRNA indicate that occludin is not required for virus attachment. We conclude that occludin plays an essential role in PEDV infection at the postbinding stages. Furthermore, we observed that macropinocytosis inhibitors blocked occludin internalization and virus entry, indicating that virus entry and occludin internalization are closely coupled. However, the macropinocytosis inhibitors could not impede virus replication once the virus had entered host cells. This suggests that occludin internalization by macropinocytosis or a macropinocytosis-like process is involved in the virus entry events. Immunofluorescence confocal microscopy showed that PEDV was trapped at cellular junctional regions upon macropinocytosis inhibitor treatment, indicating that occludin may serve as a scaffold in the vicinity of virus entry. Collectively, these data show that occludin plays an essential role in PEDV infection during late entry events. Our observation may provide novel insights into PEDV infection and related pathogenesis.IMPORTANCETight junctions are highly specialized membrane domains whose main function is to attach adjacent cells to each other, thereby forming intercellular seals. Here we investigate, for the first time, the role of the tight junction protein occludin in PEDV infection. We observed that PEDV infection induced the internalization of occludin. By using genetic modification methods, we demonstrate that occludin plays an essential role in PEDV infection. Moreover, PEDV entry and occludin internalization seem to be closely coupled. Our findings reveal a new mechanism of PEDV infection.
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Xiaolei
authors.initials: X
authors.lastname: Luo
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Longjun
authors.initials: L
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Yunfei
authors.initials: Y
authors.lastname: Xu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Weihong
authors.initials: W
authors.lastname: Gu
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China.
authors.forename: Li
authors.initials: L
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Veterinary Biotechnology, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, China wangyue@hvri.ac.cn.
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D004847:Epithelial Cells / Q000821:virology; D062793:Occludin / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D053485:Porcine epidemic diarrhea virus / Q000187:drug effects / Q000472:pathogenicity / Q000502:physiology*; D034741:RNA, Small Interfering; D013552:Swine; D019108:Tight Junctions / Q000737:chemistry* / Q000473:pathology / Q000821:virology; D014709:Vero Cells; D053585:Virus Attachment; D053586:Virus Internalization / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
chemical_list: D062793:Occludin; D034741:RNA, Small Interfering
keywords: PEDV; occludin; tight junction