HCV NS5A protein down-regulates hepcidin gene expression and increases hepatic intracellular iron storage

Abstract

To investigate whether the nonstructural protein 5A (NS5A) encoded by the hepatitis C virus RNA genome affects the expression of hepcidin gene. HCV NS5A expression plasmid (pCN5A) and pRc/CMV were transfected into QSG7701 cells individually, RT-PCR was employed to detect the HCV NS5A and hepcidin mRNA transcription. Western blot was used for detection of HCV NS5A and hepcidin proteins. Iron was stained to evaluate the intracellular iron level. HCV NS5A plasmid was successfully transfected into QSG7701 cells, which was evidenced by HCV NS5A mRNA and protein from the transfected cells. The hepcidin mRNA relative quantification in untransfected cells, pRc/CMV transfected cells and pCNS5A transfected cells were 0.711+/-0.049, 0.718+/-0.052 and 0.264+/-0.030 respectively. The transcription of hepcidin mRNA decreased remarkably in the cells transfected with pCNS5A plasmid as compared to the untransfected cells and pRc/CMV transfected cells (P less than 0.01). The level of hepcidin protein expression was found also significantly lower in the pCN5A plasmid transfected cells as compared to the untransfected cells and pRc/CMV transfected cells. The intracellular iron staining was remarkably higher in the pcNS5A transfected cells than untransfected or pRc/CMV transfected cells. HCV NS5A inhibits the transcription of hepcidin mRNA and expression of hepcidin protein, inducing hepatic intracellular iron storage.