Effect of hepatitis C virus nonstructural protein 5A and its domains II on hepatocyte gluconeogenesis in mice

Abstract

Objective: To investigate the role of hepatitis C virus nonstructural protein 5A (NS5A) and its domains I, II, and III in regulating gluconeogenesis in mice and the underlying mechanism. Methods: A total of 60 male C57BL/6J mice were randomly divided into six groups. Recombinant lentiviral particles with specific expression of full-length NS5A, NS5A domain I, NS5A domain II, or NS5A domain III were injected via the caudal vein to establish a mouse model, and the group without injection and the group with the injection of the lentiviral particles containing enhanced green fluorescent protein (EGFP) were established as negative control. The effect of full-length NS5A protein and its domains on fasting blood glucose (FBG) and fasting serum insulin (FINS) were measured. Liver tissue was collected to prepare a paraffin section. Immunohistochemistry was used to measure the expression of phosphoenolpyruvate carboxykinase (PEPCK) in hepatocytes, quantitative real-time PCR and/or Western blot were used to measure the expression of NS5A, phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK), sterol regulatory element-binding protein-1 (SREBP-1), and PEPCK. Results: Compared with the group without injection and the group with the injection of the lentiviral particles containing EGFP, the groups with the injection of the lentiviral particles containing full-length NS5A and NS5A domain II had significant increases in FBG and homeostasis model assessment of insulin resistance index (P < 0.01). Immunohistochemistry and quantitative real-time PCR showed a significant increase in the expression of PEPCK, a key enzyme involved in gluconeogenesis. Western blot showed that full-length NS5A protein and NS5A domain II inhibited the level of p-AMPK and increased the levels of SREBP-1 and PEPCK. Conclusion: NS5A protein and NS5A domain II may affect glucose metabolism in hepatocytes in mice by regulating AMPK/SREBP-1/PEPCK, and NS5A domain II may play an important role in insulin resistance in hepatocytes caused by HCV infection.