title: Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid β-oxidation.
abstract: Infection with Japanese encephalitis virus (JEV) can induce the expression of pro-inflammatory cytokines and cause acute encephalitis in humans. β-oxidation breaks down fatty acids for ATP production in mitochondria, and impaired β-oxidation can induce pro-inflammatory cytokine expression. To address the role of fatty-acid β-oxidation in JEV infection, we measured the oxygen consumption rate of mock- and JEV-infected cells cultured with or without long chain fatty acid (LCFA) palmitate. Cells with JEV infection showed impaired LCFA β-oxidation and increased interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) expression. JEV nonstructural protein 5 (NS5) interacted with hydroxyacyl-CoA dehydrogenase α and β subunits, two components of the mitochondrial trifunctional protein (MTP) involved in LCFA β-oxidation, and NS5 proteins were detected in mitochondria and co-localized with MTP. LCFA β-oxidation was impaired and higher cytokines were induced in cells overexpressing NS5 protein as compared with control cells. Deletion and mutation studies showed that the N-terminus of NS5 was involved in the MTP association, and a single point mutation of NS5 residue 19 from methionine to alanine (NS5-M19A) reduced its binding ability with MTP. The recombinant JEV with NS5-M19A mutation (JEV-NS5-M19A) was less able to block LCFA β-oxidation and induced lower levels of IL-6 and TNF-α than wild-type JEV. Moreover, mice challenged with JEV-NS5-M19A showed less neurovirulence and neuroinvasiveness. We identified a novel function of JEV NS5 in viral pathogenesis by impairing LCFA β-oxidation and inducing cytokine expression by association with MTP.
authors: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors: Yu-Ting
authors: YT
authors: Kao
authors: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors: Bi-Lan
authors: BL
authors: Chang
authors: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors: Jian-Jong
authors: JJ
authors: Liang
authors: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
authors: Hang-Jen
authors: HJ
authors: Tsai
authors: Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
authors: Yi-Ling
authors: YL
authors: Lee
authors: Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan; Department of Primary Care Medicine, Taipei Medical University Hospital, Taipei, Taiwan.
authors: Ren-Jye
authors: RJ
authors: Lin
authors: Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan; Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan; Genomics Research Center, Academia Sinica, Taipei, Taiwan.
authors: Yi-Ling
authors: YL
authors: Lin
mesh_terms: D000818:Animals; D004664:Encephalitis Virus, Japanese / Q000235:genetics / Q000378:metabolism*; D004672:Encephalitis, Japanese / Q000235:genetics / Q000378:metabolism*; D005227:Fatty Acids / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D063992:Mitochondrial Trifunctional Protein, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D063993:Mitochondrial Trifunctional Protein, beta Subunit / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D017354:Point Mutation; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D005227:Fatty Acids; C096041:NS5 protein, flavivirus; D017361:Viral Nonstructural Proteins; D063992:Mitochondrial Trifunctional Protein, alpha Subunit; D063993:Mitochondrial Trifunctional Protein, beta Subunit