Expression of Hepatitis C Virus Proteins Inhibits Signal Transduction through the Jak-STAT Pathway

Markus H. Heim, Darius Moradpour, Hubert E. Blum
1999 Journal of Virology  
Hepatitis C virus (HCV) infection is a leading cause of liver disease worldwide. Alpha interferon (IFN-α) therapy of chronic hepatitis C leads to a sustained response in 10 to 20% of patients only. The mechanisms of viral persistence and the pathogenesis of hepatitis C are poorly understood. We established continuous human cell lines, allowing the tightly regulated expression of the entire HCV open reading frame under the control of a tetracycline-responsive promoter. Using this in vitro
more » ... his in vitro system, we analyzed the effect of HCV proteins on IFN-induced intracellular signaling. Expression of HCV proteins in these cells strongly inhibited IFN-α-induced signal transduction through the Jak-STAT pathway. Inhibition occurred downstream of STAT tyrosine phosphorylation. Inhibition of the Jak-STAT pathway was not restricted to IFN-α-induced signaling but was observed in leukemia inhibitory factor-induced signaling through Stat3 as well. By contrast, tumor necrosis factor alpha-induced activation of the transcription factor NF-κB was not affected. Interference of HCV with IFN-α-induced signaling through the Jak-STAT pathway could contribute to the resistance to IFN-α therapy observed in the majority of patients and may represent a general escape strategy of HCV contributing to viral persistence and pathogenesis of chronic liver disease.
doi:10.1128/jvi.73.10.8469-8475.1999 fatcat:qanjcmjnfnekleyeyifaxyk7ui