Abstract
of steatosis. Little is known, however, on the role of LXRs in the development of hepatic steatosis in chronic HCV infection. Aim: To evaluate in an in vitro model of hepatitis C the effect of HCV NS5A and core proteins and the viral replication in the intracellular lipid accumulation and the LXR-related metabolic target gene expression. Methods: Human hepatocyte-derived cell lines Chang Liver and Huh7 were used. CHL-NS5A and CHL-core were generated by stable transfection of CHL cells with pcDNA3.1-NS5A and pEFcore expression vectors, respectively. Huh7 cells expressing full length genotype 1b HCV replicons (G1) were also established. The lipid content was determined by flow cytometry using Nile Red. LXRalpha, SREBP-1c, SREBP-2, PPAR-gamma and FAS gene expression was measured by real time PCR. Results: We found that CHL-NS5A and CHL-core exhibited an increase of lipid accumulation compared to CHL cells (+245% and +107%, respectively). Moreover mRNA levels of LXRalpha, SREBP-1c, SREBP-2, PPAR-gamma and FAS were significantly increased when NS5A and core proteins were expressed (CHL-NS5A: +356%, +232%, +196%, +7800% and +101%, respectively; CHL-core: +33%, +28%, +22%, +817% and +53%, respectively) compared to CHL. Replication of HCV in G1 cells induced intracellular lipid accumulation (+190%) associated with a significant increase in the mRNA levels of LXRalpha (+14%), SREBP-1c (+65%), SREBP-2 (+44%) and PPARgamma (+131%) compared to Huh7 cells. Conclusions: In our experimental HCV in vitro model, viral replication illustrates a significant induction in the lipogenic LXR-related downstream target genes and in the intracellular overaccumulation of lipids; this could be partially leaded by the expression of HCV NS5A and core proteins. These findings may suggest a key role of LXRa in the lipid metabolic factors associated with HCV. Supported by G/467B01/64000/3, BFU2007–62977 and SAN673/ LE06/08, Conserjeria de Sanidad, JCyL. CIBERehd is funded by Instituto de Salud Carlos III (Spain).
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