Volume 41, Issue 3, Pages 407-413 (September 2004) Molecular mechanisms regulating the antifibrogenic protein heme-oxygenase-1 in human hepatic myofibroblasts  Liying Li, Boris Julien, Pascale Grenard, Fatima Teixeira-Clerc, Ariane Mallat, Sophie Lotersztajn  Journal of Hepatology  Volume 41, Issue 3, Pages 407-413 (September 2004) DOI: 10.1016/j.jhep.2004.05.016 Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 1 Redox imbalance mediates induction of HO-1 by 15-d-PGJ2 in human hepatic myofibroblasts. (A) Regulation of HO-1 mRNA induction. Human hepatic myofibroblasts were preincubated with 5mM NAC, 5mM GSH or vehicle for 1h, and further treated with either 1μM 15-d-PGJ2 or 0.1mM DEM for 3h. (B) Regulation of HO-1 protein expression. Human hepatic myofibroblasts were pre-incubated with 5mM NAC, 5mM GSH or vehicle for 1h, and further treated with 1μM 15-d-PGJ2 or 0.1mM DEM for 9h. (C) Regulation of HO-1 protein expression. Human hepatic myofibroblasts were preincubated with 100μM deferoxamine, 10μM diphenyleneiodonium (DPI), 1mM allopurinol or vehicle for 1h, then treated with 1μM 15-d-PGJ2 for 9h. Deferoxamine, DPI or allopurinol had no effect on unstimulated HO-1. Typical autoradiograms are shown. Similar results were obtained in 2–5 experiments. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 2 Antifibrogenic effects of 15-d-PGJ2 involve oxidative stress. In (A), (B) and (C), human hepatic myofibroblasts were pretreated for 60min with either 5mM NAC, 5mM GSH or vehicle, as indicated. (A) Cells were stimulated with 5% human serum, in the presence of varying concentrations of 15-d-PGJ2 or (B) varying concentration of DEM. DNA synthesis was assessed by 5-bromo-2′-deoxy-Uridine incorporation. (C) α1 (I) collagen mRNA expression was evaluated by Northern blot analysis in cells treated for 5h with either 1μM 15-d-PGJ2 or 0.1mM DEM. Results represent the mean +/− SEM of six experiments, and are expressed as percent of control. (A) P<0.001 by ANOVA. (C) *P<0.001. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 3 15-d-PGJ2 and DEM induce depletion in glutathione levels. Effect of 15-d-PGJ2 and DEM on intracellular GSH levels. Human hepatic myofibroblasts were treated with 1μM 15-d-PGJ2 or 0.1mM DEM for varying periods of time. Intracellular GSH content was measured as described under Methods. Results are the mean ±SEM of at least six experiments. P<0.001 by ANOVA. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 4 Induction of HO-1 by 15-d-PGJ2 involves P38 MAPK. (A) Northern blot analysis of HO-1 mRNA induction in human hepatic myofibroblasts pre-incubated with 10μM PD169316 for 1h, and further treated with 1μM 15-d-PGJ2 for 3h. (B) Western blot analysis of HO-1 protein in cells pre-incubated by 10μM PD169316, 20μM U0126, 20μM SP600125 or 10μM LY-294,002 for 1h, then treated with 1μM 15-d-PGJ2 for 9h. (C) Western blot analysis of phospho-p38 MAPK in cells pretreated for 60min with either 5mM NAC or vehicle and further treated for 30min with either 1μM 15-d-PGJ2 or 0.1mM DEM. (D) Western blot analysis of IκB-α in cells pretreated for 30min with either 50ng/ml TNF-α or vehicle, and further treated with 1μM 15-d-PGJ2 for 30min. A typical auroradiogram is shown; similar results were obtained in 2–4 experiments. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 5 p38 MAPK mediates inhibition of proliferation and of α1 (I) collagen mRNA expression elicited by 15-d-PGJ2. Human hepatic myofibroblasts were pre-incubated with 10μM PD169316 or vehicle for 1h. (A) Northern blot analysis of α1 (I) collagen mRNA expression in cells treated with 1μM 15-d-PGJ2 for 5h. (B) DNA synthesis was measured after 30h treatment with 5% human serum together with 4μM 15-d-PGJ2 or vehicle. Results represent the mean +/− SEM of 5 experiments. (A) P<0.001 by ANOVA. (B) *P<0.01. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions

Fig. 6 p38 MAPK stabilizes HO-1 mRNA. Human hepatic myofibroblasts were preincubated with 1μM 15-d-PGJ2 for 5h to reach steady state, and further treated with 1mg/ml actinomycin D in the absence or presence of 10μM PD 169316 for various periods of time. HO-1 mRNA expression was analyzed by Northern blot analysis. After quantification of the autoradiographic signals, results were normalized relative to 28 S ribosomal RNA expression to correct for variations in mRNA loading and transfer. Results are the mean ±SEM of five experiments, and are expressed as percent of the remaining HO-1 mRNA signal. P<0.001 by ANOVA. Journal of Hepatology 2004 41, 407-413DOI: (10.1016/j.jhep.2004.05.016) Copyright © 2004 European Association for the Study of the Liver Terms and Conditions