title: Autophagy inhibits viral genome replication and gene expression stages in West Nile virus infection.
abstract: Autophagy is a lysosomal degradation pathway that is implicated in many viral infections. However, its role in West Nile virus (WNV) infection remains controversial. In the present study, we examined the relationship between WNV infection and autophagy in infected cells. We demonstrated that LC3-II expression, a molecular marker for autophagosomal membranes, was enhanced in WNV-infected cells 6h post-infection. LC3-II expression was further enhanced in WNV-inoculated cells when treated with a lysosomal protease inhibitor. Meanwhile, WNV replication in cells lacking Atg5, an essential factor for autophagy, was increased compared with replication in wild-type cells. In addition, WNV replication was inhibited in cells lacking Atg5 when they were transfected with an ATG5 expression plasmid. These results suggest an antiviral role for autophagy in WNV-infected cells. We also examined which viral replication stages were affected by autophagy by using a Tat-beclin 1 peptide to induce autophagy and pseudo-infectious WNV reporter virus particles (WNV-RVPs) that monitor viral genome replication and gene expression stages via GFP expression. We found that autophagy induction in HeLa cells by Tat-beclin 1 peptide 3h after WNV inoculation inhibited viral replication, and GFP expression was significantly inhibited in wild-type cells when compared with cells lacking Atg5. Taken together, these results suggest that autophagy is induced by WNV infection, and that this induction inhibits WNV replication at the viral genome replication and gene expression stages.
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Kobayashi
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Orba
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamaguchi
authors.affiliation: Department of Cancer Pathology, Hokkaido University Graduate School of Medicine, N15, W7, Kita-Ku, Sapporo 060-8638, Japan.
authors.forename: Kenta
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Michihito
authors.initials: M
authors.lastname: Sasaki
authors.affiliation: Laboratory of Veterinary Hygiene, Graduate School of Veterinary Medicine, Hokkaido University, N18, W9, Kita-ku, Sapporo 060-0818, Japan.
authors.forename: Rie
authors.initials: R
authors.lastname: Hasebe
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kimura
authors.affiliation: Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, N20, W10, Kita-ku, Sapporo 001-0020, Japan; Global Institution for Collaborative Research and Education (GI-CORE), Hokkaido University, Japan. Electronic address: h-sawa@czc.hokudai.ac.jp.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Sawa
mesh_terms: D001343:Autophagy; D000071187:Autophagy-Related Protein 5; D015536:Down-Regulation; D015967:Gene Expression Regulation, Viral; D016679:Genome, Viral; D006801:Humans; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism; D014779:Virus Replication; D014901:West Nile Fever / Q000235:genetics / Q000378:metabolism / Q000503:physiopathology* / Q000821:virology; D014902:West Nile virus / Q000235:genetics / Q000502:physiology*
chemical_list: C502778:ATG5 protein, human; D000071187:Autophagy-Related Protein 5; D008869:Microtubule-Associated Proteins; D014764:Viral Proteins
keywords: Autophagy; Flaviviruses; Host defense; Viral replication