Project description:Approximately 50% of patients with chronic hepatitis C (CHC) have a sustained virologic response (SVR) to treatment with pegylated interferon (pegINF)-α and ribavirin. Non-response 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 SVR rates >90%. We investigated mechanisms of the different responses of patients with CHC and AHC to pegIFN-α therapy. We analyzed IFN signaling and ISG expression in liver samples from patients with acute hepatitis C (AHC), patients with chronic hepatitis (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. Expression levels of 100s 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 SOCS1 or SOCS3 between liver samples from patients with AHC and those with CHC. However, USP18 (another negative regulator of IFN-α signaling), was upregulated in liver samples of patients with CHC that did not respond to therapy, but not in AHC. In conclusion, differences in expression of ISGs might account for the greater response of patients with AHC, compared to those with CHC, to treatment with pegINF-α and ribavirin. Specifically, USP18 is upregulated in liver samples of patients with CHC that do not respond to therapy, but not in patients with AHC. (Interferon-γ Stimulated Genes, but not USP18, are Expressed in Livers of Patients with Acute Hepatitis C; Dill MT, Makowska Z et al, Gastroenterology 2012 (in press)) Primary human hepatocytes from 2 donors were analyzed. From each donor there are 5 samples: untreated cells, cells treated with interferon alpha (1000 IU/ml) for 6 and 24 hours and cells treated with interferon gamma (1000 IU/ml) for 6 and 24 hours.

Project description:Interferon (IFN)-alpha causes high rates of depression and fatigue, and is used to investigate the impact of innate immune cytokines on brain and behavior. However, little is known about transcriptional profiles of circulating immune cells during chronic IFN-alpha administration. Accordingly, genome-wide transcriptional profiling was performed on peripheral blood mononuclear cells from 21 patients with chronic hepatitis C virus either awaiting IFN-alpha therapy (n=10) or after 12 weeks of IFN-alpha treatment (n=11). Significance analysis of microarray data identified 252 up-regulated gene transcripts, the majority of which were related to IFN-alpha/antiviral or innate-immune/inflammatory signaling. Of these upregulated genes, 2'-5'-oligoadenylate synthetase 2 (OAS2) was the only gene that was differentially expressed in patients that developed IFN-alpha-induced depression/fatigue, and correlated with depression and fatigue scores at 12 weeks of IFN-alpha administration. Promoter-based bioinformatic and cellular origin analyses revealed IFN-alpha-induced increases in genes bearing transcription factor binding motifs (TFBMs) related to myeloid differentiation, IFN-alpha signaling, API and CREB/ATF family of transcription pathways, with changes derived primarily from monocytes and plasmacytoid dendritic cells. Patients with high depression/fatigue scores demonstrated up-regulation of genes bearing TFBMs for myeloid differentiation, IFN-alpha and AP1 signaling, and down regulation of TFBMs for CREB/ATF-related transcription factors. Cellular origin analyses indicated a shift toward genes derived from CD8+T and NK cells in subjects with high depression/fatigue scores. These results reveal an antiviral and inflammatory transcriptional profile after 12 weeks IFN-alpha, accompanied by increased OAS2 expression, decreased CREB/ATF transcriptional control, and a shift from monocyte-derived genes to those of cytotoxic lymphocytes in IFN-alpha-induced depression/fatigue. Total RNA was isolated from the peripheral blood mononuclear cells (PBMC) obtained at 12 weeks from HCV patients treated with IFN-alpha plus ribavirin (n=11) and untreated HCV patients awaiting IFN-alpha/ribavirin therapy (control subjects, n=10).

Project description:Approximately 50% of patients with chronic hepatitis C (CHC) have a sustained virologic response (SVR) to treatment with pegylated interferon (pegINF)-α and ribavirin. Non-response 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 SVR rates >90%. We investigated mechanisms of the different responses of patients with CHC and AHC to pegIFN-α therapy. We analyzed IFN signaling and ISG expression in liver samples from patients with acute hepatitis C (AHC), patients with chronic hepatitis (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. Expression levels of 100s 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 SOCS1 or SOCS3 between liver samples from patients with AHC and those with CHC. However, USP18 (another negative regulator of IFN-α signaling), was upregulated in liver samples of patients with CHC that did not respond to therapy, but not in AHC. In conclusion, differences in expression of ISGs might account for the greater response of patients with AHC, compared to those with CHC, to treatment with pegINF-α and ribavirin. Specifically, USP18 is upregulated in liver samples of patients with CHC that do not respond to therapy, but not in patients with AHC. (Interferon-γ Stimulated Genes, but not USP18, are Expressed in Livers of Patients with Acute Hepatitis C; Dill MT, Makowska Z et al, Gastroenterology 2012 (in press))

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Interferon alfa regulated gene expression in patients initiating interferon treatment for chronic hepatitis C

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