Sylvia Brost1, Anna Zimmermann1, Ronald Koschny1, Jaromir Sykora1, Wolfgang Stremmel1, Peter Schirmacher2, Henning Walczak3, Tom M Ganten4. 1. Department of Gastroenterology, University Hospital Heidelberg, Germany. 2. Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany. 3. Center for Cell Death, Cancer and Inflamation (CCCI), University College London, United Kingdom. 4. Department of Gastroenterology, University Hospital Heidelberg, Germany. Electronic address: tom.ganten@med.uni-heidelberg.de.
Abstract
BACKGROUND AND AIMS: Treatment with pegylated interferon-alpha (PEG-IFN) and ribavirin is the backbone of standard therapy of HCV by mechanisms that are not completely understood. Besides a direct antiviral effect, different immunomodulatory and apoptotic effects have been discussed. Tumor necrosis factor-related apoptosis inducing-ligand (TRAIL) is a member of the tumor necrosis factor (TNF) family with immunomodulatory as well as pro- and antiapoptotic effects and is putatively involved in control of HCV infection. Thus, we analyzed the expression of the TRAIL/TRAIL-receptor system, caspase-8 and cFLIP and examined their prognostic and predictive value for HCV infection and antiviral therapy, respectively. METHODS: We immunohistochemically analyzed liver biopsies of 116 therapy-naive HCV patients before treatment with PEG-IFNα and ribavirin in comparison to healthy liver tissue. Expression levels of TRAIL, TRAIL-R1 to TRAIL-R4, caspase-8 and cFLIP were correlated with sustained virologic response (SVR), genotype and staging of chronic hepatitis. RESULTS: Caspase-8, cFLIP, TRAIL-R2 and TRAIL-R4 were strongly upregulated in HCV patients, whereas TRAIL-R3 was downregulated. SVR correlated with high expression of TRAIL and pro-apoptotic TRAIL-R2 on HCV infected hepatocytes. CONCLUSIONS: Our results suggest a pathophysiological role of TRAIL in both, HCV infection and therapy. Further studies need to elaborate possible TRAIL-related targets for clinical applications.
BACKGROUND AND AIMS: Treatment with pegylated interferon-alpha (PEG-IFN) and ribavirin is the backbone of standard therapy of HCV by mechanisms that are not completely understood. Besides a direct antiviral effect, different immunomodulatory and apoptotic effects have been discussed. Tumor necrosis factor-related apoptosis inducing-ligand (TRAIL) is a member of the tumor necrosis factor (TNF) family with immunomodulatory as well as pro- and antiapoptotic effects and is putatively involved in control of HCV infection. Thus, we analyzed the expression of the TRAIL/TRAIL-receptor system, caspase-8 and cFLIP and examined their prognostic and predictive value for HCV infection and antiviral therapy, respectively. METHODS: We immunohistochemically analyzed liver biopsies of 116 therapy-naive HCV patients before treatment with PEG-IFNα and ribavirin in comparison to healthy liver tissue. Expression levels of TRAIL, TRAIL-R1 to TRAIL-R4, caspase-8 and cFLIP were correlated with sustained virologic response (SVR), genotype and staging of chronic hepatitis. RESULTS:Caspase-8, cFLIP, TRAIL-R2 and TRAIL-R4 were strongly upregulated in HCV patients, whereas TRAIL-R3 was downregulated. SVR correlated with high expression of TRAIL and pro-apoptotic TRAIL-R2 on HCV infected hepatocytes. CONCLUSIONS: Our results suggest a pathophysiological role of TRAIL in both, HCV infection and therapy. Further studies need to elaborate possible TRAIL-related targets for clinical applications.