Antifibrogenic effects of histone deacetylase inhibitors on pancreatic stellate cells

• Published in: Biochemical pharmacology 2007-12, Vol.74 (12), p.1747-1757
• Main Authors: Bülow, Robin, Fitzner, Brit, Sparmann, Gisela, Emmrich, Jörg, Liebe, Stefan, Jaster, Robert
• Format: Article
• Language: English
• Subjects: Actins - metabolism; Activator protein-1; Animals; Base Sequence; Biological and medical sciences; Cells, Cultured; Collagen - biosynthesis; DNA Primers; Endothelin-1; Endothelin-1 - genetics; Enzyme Inhibitors - pharmacology; Fibrosis; Fluorescent Antibody Technique; Histone Deacetylase Inhibitors; Liver Cirrhosis - prevention & control; Male; Medical sciences; Pancreas - cytology; Pancreas - drug effects; Pancreatic stellate cells; Pharmacology. Drug treatments; Rats; Rats, Inbred Lew; Reverse Transcriptase Polymerase Chain Reaction; Transcription Factor AP-1 - metabolism; Transforming Growth Factor beta - genetics; Transforming growth factor-β
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/j.bcp.2007.08.023

Pancreatic stellate cells (PSCs) are essentially involved in pancreatic fibrogenesis and considered as a target for antifibrotic therapies. Here, we have analyzed the effects of three histone deacetylase inhibitors (HDACIs), sodium butyrate, sodium valproate (VPA) and trichostatin A (TSA), on profibrogenic activities of PSC and elucidated molecular targets of HDACI action. Therefore, cultured PSCs were exposed to HDACI. Cell proliferation and viability were assessed by 5-bromo-2′-deoxyuridine (BrdU) incorporation and trypan blue staining assays. Exhibition of the myofibroblastic PSC phenotype was monitored by immunofluorescence analysis of α-smooth muscle actin (α-SMA) expression. [ 3H]-proline incorporation into acetic acid-soluble proteins was measured to quantify collagen synthesis. Levels of mRNA were determined by quantitative reverse transcriptase real-time PCR. Protein expression, phosphorylation and acetylation were analyzed by immunoblotting, and gel shift assays were performed to study DNA binding of nuclear proteins. HDACI enhanced histone H3 acetylation in a dose-dependent manner. In the same dose range, they strongly inhibited cell proliferation, α-SMA expression and collagen synthesis. A significantly increased rate of cell death was observed in response to TSA at 1 μM. While all three HDACI inhibited mRNA expression of endothelin-1, only VPA significantly reduced expression of transforming growth factor-β1. Both mediators exert autocrine profibrogenic effects on PSC. Furthermore, HDACI-treated PSC displayed a diminished DNA binding of AP-1, a key transcription factor in profibrogenic signaling. Together, the results suggest that HDACI exert antifibrogenic effects on PSC. Interruption of AP-1 signaling and autocrine loops enhancing PSC activation might be key mechanisms of HDACI action.