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Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid ?-oxidation.

ABSTRACT: Infection with Japanese encephalitis virus (JEV) can induce the expression of pro-inflammatory cytokines and cause acute encephalitis in humans. ?-oxidation breaks down fatty acids for ATP production in mitochondria, and impaired ?-oxidation can induce pro-inflammatory cytokine expression. To address the role of fatty-acid ?-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 ?-oxidation and increased interleukin 6 (IL-6) and tumor necrosis factor ? (TNF-?) expression. JEV nonstructural protein 5 (NS5) interacted with hydroxyacyl-CoA dehydrogenase ? and ? subunits, two components of the mitochondrial trifunctional protein (MTP) involved in LCFA ?-oxidation, and NS5 proteins were detected in mitochondria and co-localized with MTP. LCFA ?-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 ?-oxidation and induced lower levels of IL-6 and TNF-? 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 ?-oxidation and inducing cytokine expression by association with MTP.

SUBMITTER: Kao YT

PROVIDER: S-EPMC4376648 | biostudies-literature | 2015 Mar

REPOSITORIES: biostudies-literature

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Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid β-oxidation.

Kao Yu-Ting YT Chang Bi-Lan BL Liang Jian-Jong JJ Tsai Hang-Jen HJ Lee Yi-Ling YL Lin Ren-Jye RJ Lin Yi-Ling YL

PLoS pathogens 20150327 3

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 wi ...[more]

PMID: 25816318

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Project description:Japanese encephalitis virus (JEV) is a mosquito-transmitted flavivirus that is closely related to other emerging viral pathogens, including dengue virus (DENV), West Nile virus (WNV), and Zika virus (ZIKV). JEV infection can result in meningitis and encephalitis, which in severe cases cause permanent brain damage and death. JEV occurs predominantly in rural areas throughout Southeast Asia, the Pacific Islands, and the Far East, causing around 68,000 cases of infection worldwide each year. In this report, we present a 2.1-Å-resolution crystal structure of the C-terminal ?-ladder domain of JEV nonstructural protein 1 (NS1-C). The surface charge distribution of JEV NS1-C is similar to those of WNV and ZIKV but differs from that of DENV. Analysis of the JEV NS1-C structure, with in silico molecular dynamics simulation and experimental solution small-angle X-ray scattering, indicates extensive loop flexibility on the exterior of the protein. This, together with the surface charge distribution, indicates that flexibility influences the protein-protein interactions that govern pathogenicity. These factors also affect the interaction of NS1 with the 22NS1 monoclonal antibody, which is protective against West Nile virus infection. Liposome and heparin binding assays indicate that only the N-terminal region of NS1 mediates interaction with membranes and that sulfate binding sites common to NS1 structures are not glycosaminoglycan binding interfaces. This report highlights several differences between flavivirus NS1 proteins and contributes to our understanding of their structure-pathogenic function relationships.IMPORTANCE JEV is a major cause of viral encephalitis in Asia. Despite extensive vaccination, epidemics still occur. Nonstructural protein 1 (NS1) plays a role in viral replication, and, because it is secreted, it can exhibit a wide range of interactions with host proteins. NS1 sequence and protein folds are conserved within the Flavivirus genus, but variations in NS1 protein-protein interactions among viruses likely contribute to differences in pathogenesis. Here, we compared characteristics of the C-terminal ?-ladder domain of NS1 between flaviviruses, including surface charge, loop flexibility, epitope cross-reactivity, membrane adherence, and glycosaminoglycan binding. These structural features are central to NS1 functionality and may provide insight into the development of diagnostic tests and therapeutics.

Dataset Information

Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid ?-oxidation.

Publications

Japanese encephalitis virus nonstructural protein NS5 interacts with mitochondrial trifunctional protein and impairs fatty acid β-oxidation.

Similar Datasets

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