Hepcidin/ferroportin expression levels involve efficacy of pegylated-interferon plus ribavirin in hepatitis C virus-infected liver

Abstract

Aim: To investigate the relationship between the iron-metabolism-related gene expression profiles and efficacy of antiviral therapy in chronic hepatitis C patients.

Methods: The hepatic expression profile of iron-metabolism-related genes was analyzed and its association with virological response to pegylated-interferon plus ribavirin combination therapy was evaluated. A hundred patients with chronic hepatitis C (genotype1b, n = 50; genotype 2, n = 50) were enrolled and retrospectively analyzed. Liver biopsy samples were subjected to quantitative polymerase chain reaction for iron-metabolism-related genes and protein expression (Western blotting analysis) for ferroportin. As a control, normal liver tissue was obtained from 18 living donors of liver transplantation. Serum hepcidin level was measured by sensitive liquid chromatography/electrospray ionization tandem mass spectrometry.

Results: Iron overload is associated with liver damage by increasing oxidative stress and hepatitis C virus (HCV) is reported to induce iron accumulation in hepatocytes in vivo. Conversely, iron administration suppresses HCV replication in vitro. Therefore, the association between HCV infection and iron metabolism remains unclear. Compared with controls, patients had significantly higher gene expression for transferrin, iron-regulatory proteins 1 and 2, divalent metal transporter 1, and ferroportin, but similar for transferrin receptors 1 and 2, and hepcidin. When the expression profiles were compared between sustained virological response (SVR) and non-SVR patients, the former showed significantly lower transcription and protein expression of hepcidin and ferroportin. Expression of hepcidin-regulating genes, BMPR1, BMPR2, and hemojuvelin, was significantly increased, whereas BMP2 was decreased in HCV-infected liver. BMPR2 and hemojuvelin expression was significantly lower in the SVR than non-SVR group. HCV infection affects the expression of iron-metabolism-related genes, leading to iron accumulation in hepatocytes.

Conclusion: Decreased expression of hepcidin and ferroportin in SVR patients indicates the importance of hepatocytic iron retention for viral response during pegylated-interferon plus ribavirin treatment.

Keywords: Chronic hepatitis C; Ferroportin; Hepcidin; Interferon; Iron-metabolism.

Figure 1

Expression levels of iron-metabolism-related genes in hepatitis C virus-infected liver in each genotype. The levels were measured by real-time reverse transcription polymerase chain reaction. ^aP < 0.05 vs genotype1b, ^bP < 0.01 vs genotype1b, ^cP < 0.05 vs control, ^dP < 0.01 vs control.

Figure 2

Expression levels of hepcidin and ferroportin genes. A: Sustained virological response (SVR) vs non-SVR; B: Genotype 1b vs 2a/2b; C: RBV dose reduction (+) vs (−). The levels were measured by real-time reverse transcription polymerase chain reaction. ^aP< 0.05 vs SVR, ^bP < 0.01 vs SVR, ^cP < 0.05 vs control, ^dP < 0.01 vs control.

Figure 3

Protein expression of hepcidin and ferroportin. A: Serum hepcidin levels measured by sensitive liquid chromatography/electrospray ionization tandem mass spectrometry (total hepcidin and its two isoforms, Hep-20 and Hep 25); B: Ferroportin levels in the liver measured by Western blotting. ^aP < 0.05 vs sustained virological response (SVR).

Figure 4

Expression levels of genes regulating hepcidin expression. The levels were measured by real-time reverse transcription polymerase chain reaction. ^aP < 0.05 vs sustained virological response (SVR), ^bP < 0.01 vs SVR, ^dP < 0.01 vs control.