Up-regulation of IL-12 expression in patients with chronic hepatitis B is mediated by the PI3K/Akt pathway

Hepatitis B virus (HBV) replicates noncytopathically in hepatocytes, but HBV or proteins encoded by HBV genome could induce cytokines, chemokines expression by hepatocytes.IL-12 is a typical proinflammatory cytokine that plays a critical role in host defense against pathogens, including the HBV. However, the role of IL-12 in chronic hepatitis B (CHB) remains unclear. The aims of this study were to detect the expression of IL-12 in CHB patients and explore the molecular mechanism of HBV-induced IL-12 expression. The results showed that serum levels and hepatic expression of IL-12 were significantly upregulated in CHB patients. HBx protein increased IL-12 expression in a dose-dependent manner. Furthermore, inhibition of PI3K/Akt significantly decreased the HBx-induced IL-12 expression and Akt activation. Taken together, these results indicate that the molecular mechanism of HBV-induced IL-12 expression involves activation of the PI3K/Akt pathway by HBx, leading to transactivation of the IL-12 p35 and p40 promoters.