title: Japanese encephalitis virus replication is negatively regulated by autophagy and occurs on LC3-I- and EDEM1-containing membranes.
abstract: Autophagy is a lysosomal degradative pathway that has diverse physiological functions and plays crucial roles in several viral infections. Here we examine the role of autophagy in the life cycle of JEV, a neurotropic flavivirus. JEV infection leads to induction of autophagy in several cell types. JEV replication was significantly enhanced in neuronal cells where autophagy was rendered dysfunctional by ATG7 depletion, and in Atg5-deficient mouse embryonic fibroblasts (MEFs), resulting in higher viral titers. Autophagy was functional during early stages of infection however it becomes dysfunctional as infection progressed resulting in accumulation of misfolded proteins. Autophagy-deficient cells were highly susceptible to virus-induced cell death. We also observed JEV replication complexes that are marked by nonstructural protein 1 (NS1) and dsRNA colocalized with endogenous LC3 but not with GFP-LC3. Colocalization of NS1 and LC3 was also observed in Atg5 deficient MEFs, which contain only the nonlipidated form of LC3. Viral replication complexes furthermore show association with a marker of the ER-associated degradation (ERAD) pathway, EDEM1 (ER degradation enhancer, mannosidase α-like 1). Our data suggest that virus replication occurs on ERAD-derived EDEM1 and LC3-I-positive structures referred to as EDEMosomes. While silencing of ERAD regulators EDEM1 and SEL1L suppressed JEV replication, LC3 depletion exerted a profound inhibition with significantly reduced RNA levels and virus titers. Our study suggests that while autophagy is primarily antiviral for JEV and might have implications for disease progression and pathogenesis of JEV, nonlipidated LC3 plays an important autophagy independent function in the virus life cycle.
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India; Department of Biotechnology; Faculty of Science; Jamia Hamdard; New Delhi, India.
authors.forename: Manish
authors.initials: M
authors.lastname: Sharma
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Sankar
authors.initials: S
authors.lastname: Bhattacharyya
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India; Department of Biotechnology; Faculty of Science; Jamia Hamdard; New Delhi, India.
authors.forename: Minu
authors.initials: M
authors.lastname: Nain
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Manpreet
authors.initials: M
authors.lastname: Kaur
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Sood
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Vishal
authors.initials: V
authors.lastname: Gupta
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Renu
authors.initials: R
authors.lastname: Khasa
authors.affiliation: Department of Biotechnology; Faculty of Science; Jamia Hamdard; New Delhi, India.
authors.forename: Malik Z
authors.initials: MZ
authors.lastname: Abdin
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Sudhanshu
authors.initials: S
authors.lastname: Vrati
authors.affiliation: Vaccine and Infectious Disease Research Centre; Translational Health Science and Technology Institute; Gurgaon, Haryana India.
authors.forename: Manjula
authors.initials: M
authors.lastname: Kalia
mesh_terms: D000818:Animals; D001343:Autophagy / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D004664:Encephalitis Virus, Japanese / Q000502:physiology*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D060746:Endoplasmic Reticulum-Associated Degradation / Q000235:genetics / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D051379:Mice; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D014779:Virus Replication / Q000502:physiology*
chemical_list: C434526:Edem1 protein, mouse; C480860:Map1lc3b protein, mouse; D008565:Membrane Proteins; D008869:Microtubule-Associated Proteins
keywords: Atg5; EDEMosome; MEF; NS1; Neuro2a; flavivirus