title: Hepatitis C virus NS5A protein enhances gluconeogenesis through  upregulation of Akt-/JNK-PEPCK signalling pathways.
abstract: OBJECTIVE
  Hepatitis C virus (HCV) infection is highly associated with the type 2 diabetes mellitus, but the detailed mechanisms by which the viral proteins are involved in the clinical outcome remain unclear.
  
  
  METHODS
  A cDNA microarray analysis was performed following introducing an NS5A-encoding plasmid or a control vector into a mouse system by hydrodynamics- based transfection. Differentially expressed genes that are associated with gluconeogenesis were selected and their expression levels in HCV patients, in NS5A-expressing systems, and in the viral subgenomic replicon system were further examined by real-time quantitative polymerase chain reaction and Western blot analysis.
  
  
  RESULTS
  Differential gene expression including an upregulation of the gluconeogenic rate-limiting enzyme phosphoenolpyruvate carboxykinase (PEPCK) compared with controls was detected in mouse hepatocytes expressing HCV NS5A and in HCV patients with diabetes. In addition, an NS5A-dependent increase in glucose production was demonstrated in human primary hepatocytes. The upregulation of PEPCK and peroxisome proliferator-activated receptor-c coactivator-1a (PGC-1a) were also detected in NS5A-expressing cells and in the viral genotype 1b subgenomic replicon system. Further studies demonstrated that the NS5A-mediated upregulation of PEPCK and PGC-1a genes were resulted from the activation of PI3K-Akt and JNK signalling pathways. In addition, the expression levels of the forkhead transcription factor FoxO1 and the liver-enriched transcription factor HNF-4a were increased in HCV NS5A expressing cells.
  
  
  CONCLUSIONS
  By upregulating the expression of PEPCK gene via its transactivators FoxO1 and HNF-4a, and the coactivator PGC-1a, the NS5A promotes the production of hepatic glucose which may contribute to the development of HCV-associated type 2 diabetes mellitus.
authors.forename: Yi-Chen
authors.initials: YC
authors.lastname: Kuo
authors.forename: I-Yin
authors.initials: IY
authors.lastname: Chen
authors.forename: Shin C
authors.initials: SC
authors.lastname: Chang
authors.forename: Shun-Chi
authors.initials: SC
authors.lastname: Wu
authors.forename: Tzu-Min
authors.initials: TM
authors.lastname: Hung
authors.forename: Po-Huang
authors.initials: PH
authors.lastname: Lee
authors.forename: Kunitada
authors.initials: K
authors.lastname: Shimotohno
authors.forename: Ming-Fu
authors.initials: MF
authors.lastname: Chang
mesh_terms: D000818:Animals; D015153:Blotting, Western; D003924:Diabetes Mellitus, Type 2 / Q000209:etiology / Q000821:virology*; D005786:Gene Expression Regulation / Q000502:physiology*; D005943:Gluconeogenesis / Q000502:physiology*; D005947:Glucose / Q000378:metabolism; D016174:Hepacivirus / Q000378:metabolism*; D006526:Hepatitis C / Q000150:complications*; D022781:Hepatocytes / Q000378:metabolism; D006801:Humans; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D051379:Mice; D020411:Oligonucleotide Array Sequence Analysis; D051058:Oncogene Protein v-akt / Q000378:metabolism; D019764:Phosphoenolpyruvate Carboxykinase (ATP) / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology*; D014162:Transfection; D017361:Viral Nonstructural Proteins / Q000378:metabolism*; D012324:RNA-Dependent RNA Polymerase
chemical_list: D005947:Glucose; D048670:MAP Kinase Kinase 4; D051058:Oncogene Protein v-akt; D019764:Phosphoenolpyruvate Carboxykinase (ATP); D017361:Viral Nonstructural Proteins; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase