title: Japanese encephalitis virus NS2B-NS3 protease induces caspase 3 activation and mitochondria-mediated apoptosis in human medulloblastoma cells.
abstract: Japanese encephalitis virus (JEV) causes severe neurological diseases with a high fatality rate. Clinical, neurophysiological and radiological features of Japanese encephalitis JE patients showed that JEV infection resulted in widespread involvement of the nervous system, including thalamus, basal ganglia, brainstem, cerebellum, cerebral cortex and spinal cord. In this study, we characterized the apoptotic effect of JEV infection and its viral proteins on the TE671 human medulloblastoma cells. JEV replicated in TE671 cells, inducing caspase 3-mediated apoptosis in MOI- and time-dependent manners. Of viral proteins, co-expression of JEV NS3 protease with NS2B cofactor significantly induced higher degrees of apoptosis and triggered higher caspase 3 activities than single expression of E, NS1, NS2B or NS3 protease in human medulloblastoma cells. Moreover, JEV NS2B-NS3 protease induced reduction of mitochondrial membrane potential and release of mitochondrial cytochrome C, which were responsible for the mitochondria-mediated apoptosis. In addition, the production of reactive oxygen species production and activation of ASK1-p38 MAPK signaling pathway might be associated with JEV NS2B-NS3 protease-induced mitochondria-mediated apoptosis. The results demonstrated that the JEV infection and the co-expression of JEV NS3 protease with NS2B cofactor induced caspase 3 activation and mitochondria-mediated apoptosis in human medulloblastoma cells, being valuable insight for cellular and molecular levels of JEV pathogenesis.
authors.affiliation: Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung 404, Taiwan.
authors.forename: Tsuey-Ching
authors.initials: TC
authors.lastname: Yang
authors.forename: Su-Lian
authors.initials: SL
authors.lastname: Shiu
authors.forename: Pei-Hsin
authors.initials: PH
authors.lastname: Chuang
authors.forename: Ying-Ju
authors.initials: YJ
authors.lastname: Lin
authors.forename: Lei
authors.initials: L
authors.lastname: Wan
authors.forename: Yu-Ching
authors.initials: YC
authors.lastname: Lan
authors.forename: Cheng-Wen
authors.initials: CW
authors.lastname: Lin
mesh_terms: D017209:Apoptosis; D053148:Caspase 3 / Q000378:metabolism*; D053453:Caspase 9 / Q000378:metabolism; D002460:Cell Line; D045304:Cytochromes c / Q000378:metabolism; D004664:Encephalitis Virus, Japanese / Q000201:enzymology*; D004789:Enzyme Activation; D006801:Humans; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial; D008928:Mitochondria / Q000378:metabolism*; D020365:RNA Helicases / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D012697:Serine Endopeptidases / Q000502:physiology; D017361:Viral Nonstructural Proteins / Q000502:physiology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
chemical_list: D053148:Caspase 3; D053453:Caspase 9; D045304:Cytochromes c; D048848:MAP Kinase Kinase Kinase 5; D020365:RNA Helicases; D017382:Reactive Oxygen Species; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; D048051:p38 Mitogen-Activated Protein Kinases; C080102:NS2B protein, flavivirus; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases