Japanese Encephalitis Virus Nonstructural Protein NS5 Interacts with Mitochondrial Trifunctional Protein and Impairs Fatty Acid β-Oxidation

PLoS Pathogens

Yi-Ling Lin¹  Yu-Ting Kao²  Yi-Ling Lee²  Hang-Jen Tsai³  Bi-Lan Chang³  Ren-Jye Lin³  Jian-Jong Liang³ 

[1] Department of General Medicine, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan;Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan;Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan

关键词: Mitochondria;    Cytokines;    Fatty acids;    Viral replication;    Proteases;    Immunoprecipitation;    Neurovirulence;    West Nile virus;   

DOI  :  10.1371/journal.ppat.1004750

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

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.

【 授权许可】

CC BY