Hepatitis C virus (HCV) infection may cause liver diseases of various severities ranging from primary acute infection to life-threatening diseases, such as cirrhosis or hepatocellular carcinoma with poor prognosis. According to clinical findings, HCV infection may also lead to some extra-hepatic symptoms, including type 2 diabetes mellitus (DM). Since insulin resistance is the major etiology for type 2 DM and numerous evidences showed that HCV infection associated with insulin resistance, the involvement of E2 in the pathogenesis of type 2 DM and underlying mechanisms were investigated in this study.
Reverse transcription and real-time PCR, Western blot assay, Immunoprecipitation, Glucose uptake assay and analysis of cellular glycogen content.
Results showed that E2 influenced on protein levels of insulin receptor substrate-1 (IRS-1) and impaired insulin-induced Ser308 phosphorylation of Akt/PKB and Ser9 phosphorylation of GSK3β in Huh7 cells, leading to an inhibition of glucose uptake and glycogen synthesis, respectively, and eventually insulin resistance.
Therefore, HCV E2 protein indeed involved in the pathogenesis of type 2 DM by inducing insulin resistance.
Keywords: Hepatitis C virus, E2 envelope protein, Type 2 diabetes mellitus, Insulin resistance, Insulin receptor substrate-1 (IRS-1), GSK3β