Michael T Dill1, Zuzanna Makowska2, Francois H T Duong2, Franzisca Merkofer2, Magdalena Filipowicz2, Thomas F Baumert3, Luigi Tornillo4, Luigi Terracciano4, Markus H Heim5. 1. Department of Biomedicine, Hepatology Laboratory, University of Basel, Basel, Switzerland; Division of Gastroenterology and Hepatology, University Hospital Basel, Basel, Switzerland. 2. Department of Biomedicine, Hepatology Laboratory, University of Basel, Basel, Switzerland. 3. Inserm, U748, University of Strasbourg, Strasbourg, France. 4. Institute of Pathology, University Hospital Basel, Basel, Switzerland. 5. Department of Biomedicine, Hepatology Laboratory, University of Basel, Basel, Switzerland; Division of Gastroenterology and Hepatology, University Hospital Basel, Basel, Switzerland. Electronic address: markus.heim@unibas.ch.
Abstract
BACKGROUND & AIMS: Approximately 50% of patients with chronic hepatitis C (CHC) have a sustained virologic response to treatment with pegylated interferon (pegIFN)-α and ribavirin. Nonresponse to treatment is associated with constitutively increased expression of IFN-stimulated genes (ISGs) in the liver. Treatment of patients with acute hepatitis C (AHC) is more effective, with sustained virologic response rates greater than 90%. We investigated mechanisms of the different responses of patients with CHC and AHC to pegIFN-α therapy. METHODS: We analyzed IFN signaling and ISG expression in liver samples from patients with AHC, patients with CHC, and individuals without hepatitis C (controls) using microarray, immunohistochemical, and protein analyses. Findings were compared with those from primary human hepatocytes stimulated with IFN-α or IFN-γ, as reference sets. RESULTS: Expression levels of hundreds of genes, primarily those regulated by IFN-γ, were altered in liver samples from patients with AHC compared with controls. Expression of IFN-γ-stimulated genes was induced in liver samples from patients with AHC, whereas expression of IFN-α-stimulated genes was induced in samples from patients with CHC. In an expression analysis of negative regulators of IFN-α signaling, we did not observe differences in expression of suppresor of cytokine signaling 1 or SOCS3 between liver samples from patients with AHC and those with CHC. However, USP18 (another negative regulator of IFN-α signaling), was up-regulated in liver samples of patients with CHC that did not respond to therapy, but not in AHC. CONCLUSIONS: Differences in expression of ISGs might account for the greater response of patients with AHC, compared with those with CHC, to treatment with pegIFN-α and ribavirin. Specifically, USP18 is up-regulated in liver samples of patients with CHC that did not respond to therapy, but not in patients with AHC.
BACKGROUND & AIMS: Approximately 50% of patients with chronic hepatitis C (CHC) have a sustained virologic response to treatment with pegylated interferon (pegIFN)-α and ribavirin. Nonresponse to treatment is associated with constitutively increased expression of IFN-stimulated genes (ISGs) in the liver. Treatment of patients with acute hepatitis C (AHC) is more effective, with sustained virologic response rates greater than 90%. We investigated mechanisms of the different responses of patients with CHC and AHC to pegIFN-α therapy. METHODS: We analyzed IFN signaling and ISG expression in liver samples from patients with AHC, patients with CHC, and individuals without hepatitis C (controls) using microarray, immunohistochemical, and protein analyses. Findings were compared with those from primary human hepatocytes stimulated with IFN-α or IFN-γ, as reference sets. RESULTS: Expression levels of hundreds of genes, primarily those regulated by IFN-γ, were altered in liver samples from patients with AHC compared with controls. Expression of IFN-γ-stimulated genes was induced in liver samples from patients with AHC, whereas expression of IFN-α-stimulated genes was induced in samples from patients with CHC. In an expression analysis of negative regulators of IFN-α signaling, we did not observe differences in expression of suppresor of cytokine signaling 1 or SOCS3 between liver samples from patients with AHC and those with CHC. However, USP18 (another negative regulator of IFN-α signaling), was up-regulated in liver samples of patients with CHC that did not respond to therapy, but not in AHC. CONCLUSIONS: Differences in expression of ISGs might account for the greater response of patients with AHC, compared with those with CHC, to treatment with pegIFN-α and ribavirin. Specifically, USP18 is up-regulated in liver samples of patients with CHC that did not respond to therapy, but not in patients with AHC.
Authors: Stefan Wieland; Zuzanna Makowska; Benedetta Campana; Diego Calabrese; Michael T Dill; Josan Chung; Francis V Chisari; Markus H Heim Journal: Hepatology Date: 2014-04-25 Impact factor: 17.425
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