title: Autophagy benefits the replication of Newcastle disease virus in chicken cells and tissues.
abstract: Newcastle disease virus (NDV) is an important avian pathogen. We previously reported that NDV triggers autophagy in U251 glioma cells, resulting in enhanced virus replication. In this study, we investigated whether NDV triggers autophagy in chicken cells and tissues to enhance virus replication. We demonstrated that NDV infection induced steady-state autophagy in chicken-derived DF-1 cells and in primary chicken embryo fibroblast (CEF) cells, evident through increased double- or single-membrane vesicles, the accumulation of green fluorescent protein (GFP)-LC3 dots, and the conversion of LC3-I to LC3-II. In addition, we measured autophagic flux by monitoring p62/SQSTM1 degradation, LC3-II turnover, and GFP-LC3 lysosomal delivery and proteolysis, to confirm that NDV infection induced the complete autophagic process. Inhibition of autophagy by pharmacological inhibitors and RNA interference reduced virus replication, indicating an important role for autophagy in NDV infection. Furthermore, we conducted in vivo experiments and observed the conversion of LC3-I to LC3-II in heart, liver, spleen, lung, and kidney of NDV-infected chickens. Regulation of the induction of autophagy with wortmannin, chloroquine, or starvation treatment affects NDV production and pathogenesis in tissues of both lung and intestine; however, treatment with rapamycin, an autophagy inducer of mammalian cells, showed no detectable changes in chicken cells and tissues. Moreover, administration of the autophagy inhibitor wortmannin increased the survival rate of NDV-infected chickens. Our studies provide strong evidence that NDV infection induces autophagy which benefits NDV replication in chicken cells and tissues.
authors.affiliation: Department of Avian Infectious Diseases, Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai, People's Republic of China.
authors.forename: Yingjie
authors.initials: Y
authors.lastname: Sun
authors.forename: Shengqing
authors.initials: S
authors.lastname: Yu
authors.forename: Na
authors.initials: N
authors.lastname: Ding
authors.forename: Chunchun
authors.initials: C
authors.lastname: Meng
authors.forename: Songshu
authors.initials: S
authors.lastname: Meng
authors.forename: Shilei
authors.initials: S
authors.lastname: Zhang
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhan
authors.forename: Xusheng
authors.initials: X
authors.lastname: Qiu
authors.forename: Lei
authors.initials: L
authors.lastname: Tan
authors.forename: Hongjun
authors.initials: H
authors.lastname: Chen
authors.forename: Cuiping
authors.initials: C
authors.lastname: Song
authors.forename: Chan
authors.initials: C
authors.lastname: Ding
mesh_terms: D000818:Animals; D001343:Autophagy; D002478:Cells, Cultured; D002642:Chick Embryo; D046529:Microscopy, Electron, Transmission; D009522:Newcastle disease virus / Q000502:physiology*; D034622:RNA Interference; D014779:Virus Replication