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Virus-induced over-expression of protein phosphatase 2A inhibits insulin signalling in chronic hepatitis C

Bernsmeier, Christine
Duong, Francois H T.
Christen, Verena
Terracciano, Luigi
Heim, Markus H.
Published in Journal of hepatology. 2008, vol. 49, no. 3, p. 429-40
Abstract BACKGROUND/AIMS: Hepatitis C virus (HCV) infection disturbs glucose and lipid metabolism contributing to the development of liver steatosis, insulin resistance and type 2 diabetes mellitus. On the other hand, insulin resistance and steatosis have been found to be associated with increased rates of fibrosis progression and lower rates of response to interferon therapy in chronic hepatitis C (CHC). The molecular mechanisms contributing to insulin resistance in CHC are not well understood. We have shown previously that protein phosphatase 2A (PP2A) is over-expressed in biopsies from patients with CHC. In this study, we tested if PP2A over-expression leads to insulin resistance. METHODS: We studied insulin signalling in cell lines that allow the regulated over-expression of HCV proteins and of the PP2A catalytic subunit (PP2Ac). Insulin signalling and PP2Ac expression were also studied in HCV transgenic mice and in liver biopsies from patients with CHC. RESULTS: Over-expression of PP2Ac in cells inhibited insulin signalling by dephosphorylation of PKB/Akt. PP2Ac over-expression and impaired insulin signalling were found in the liver of HCV transgenic mice and in liver biopsies of patients with CHC. CONCLUSIONS: HCV-induced over-expression of PP2A in the liver contributes to the pathogenesis of insulin resistance in patients with CHC.
Keywords AdultAgedAnimalsBiopsyCell LineFemaleGene Expression Regulation, Enzymologic/physiologyHepacivirus/physiologyHepatitis C, Chronic/metabolism/physiopathologyHumansInsulin/metabolismInsulin Resistance/physiologyLiver/metabolism/pathology/virologyMaleMiceMice, TransgenicMiddle AgedProtein Kinases/metabolismProtein Phosphatase 2/genetics/metabolismProto-Oncogene Proteins c-akt/antagonists & inhibitorsSignal Transduction/physiology
PMID: 18486982
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Research group Etudes et traitement de l'hépatite C et B (554)
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BERNSMEIER, Christine et al. Virus-induced over-expression of protein phosphatase 2A inhibits insulin signalling in chronic hepatitis C. In: Journal of hepatology, 2008, vol. 49, n° 3, p. 429-40. doi: 10.1016/j.jhep.2008.04.007 https://archive-ouverte.unige.ch/unige:2430

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Deposited on : 2009-08-13

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