calpastatin and Hepatitis-C

The hepatitis C virus (HCV) structural core and non-structural NS5A proteins induce in liver cells a series of intracellular events, including elevation of reactive oxygen and nitrogen species (ROS/RNS). Since oxidative stress is associated to altered intracellular Ca(2+) homeostasis, we aimed to investigate the effect of these proteins on Ca(2+) mobilization in human hepatocyte-derived transfected cells, and the protective effect of quercetin treatment.. Ca(2+) mobilization and actin reorganization were determined by spectrofluorimetry. Production of ROS/RNS was determined by flow cytometry.. Cells transfected with NS5A and core proteins showed enhanced ROS/RNS production and resting cytosolic Ca(2+) concentration, and reduced Ca(2+) concentration into the stores. Phenylephrine-evoked Ca(2+) release, Ca(2+) entry and extrusion by the plasma membrane Ca(2+)-ATPase were significantly reduced in transfected cells. Similar effects were observed in cytokine-activated cells. Phenylephrine-evoked actin reorganization was reduced in the presence of core and NS5A proteins. These effects were significantly prevented by quercetin. Altered Ca(2+) mobilization and increased calpain activation were observed in replicon-containing cells.. NS5A and core proteins induce oxidative stress-mediated Ca(2+) homeostasis alterations in human hepatocyte-derived cells, which might underlie the effects of both proteins in the pathogenesis of liver disorders associated to HCV infection.

Topics: Actins; Antioxidants; Calcium; Calcium Signaling; Calcium-Binding Proteins; Cell Line; Cell Survival; Cysteine Proteinase Inhibitors; Cytokines; Hepacivirus; Hepatitis C; Hepatocytes; Homeostasis; Humans; Oxidative Stress; Quercetin; Reactive Nitrogen Species; Reactive Oxygen Species; Viral Core Proteins; Viral Nonstructural Proteins; Virus Replication