Aims: 

Hepatitis C virus (HCV) structural core and non-structural NS5A proteins participate in the development of C type hepatitis associated to the formation of reactive oxygen and nitrogen species (ROS/RNS). There is a relationship between oxidative stress and abnormal Ca²⁺ homeostasis. Here we explored the effect of HCV core and NS5A proteins on Ca²⁺ mobilization in the human hepatocyte-derived cell line Chang Liver (CHL) and the involvement of ROS/RNS.

Methods: 

CHL stably transfected with HCV core and NS5A proteins, and CHL transfected with empty vector as control, were used. Ca²⁺ mobilization was determined by spectrofluorimetry. Production of ROS and RNS was determined by flow cytometry.

Results: 

Cells transfected with NS5A and core proteins showed enhanced ROS/RNS production and resting cytosolic Ca²⁺ concentration. NS5A and core proteins transfection reduced the ability of cells to accumulate Ca²⁺ into the intracellular stores, which results in reduced phenylephrine-evoked Ca²⁺ release. Post-stimulus Ca²⁺ concentration was found to be greater in transfected cells, thus suggesting that the activity of the mechanisms involved in cytosolic Ca²⁺ clearance, including the plasma membrane Ca²⁺-ATPase, were reduced. This leads to enhanced cytosolic Ca²⁺ concentration and Ca²⁺ release from the intracellular stores through the Ca²⁺-induced Ca²⁺ release. Treatment with quercetin reduced ROS/RNS formation and reversed the effect of HCV proteins on Ca²⁺ mobilization.

Conclusions: 

HCVcore and NS5A proteins induce abnormal Ca²⁺ homeostasis in CHL, mediated by oxidative and nitrosative stress, which contributes to the pathogenesis of HCV infection.

Supported by BFU2007-60104 and BFU2007-62977 and SAN673/LE06/08 of Conserjería de Sanidad de JCyL. CIBERehd is funded by the Instituto de Salud Carlos III (Spain).