Antifibrogenic effects of histone deacetylase inhibitors on pancreatic stellate cells.
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 alpha-smooth muscle actin (alpha-SMA) expression. [(3)H]-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, alpha-SMA expression and collagen synthesis. A significantly increased rate of cell death was observed in response to TSA at 1 microM. While all three HDACI inhibited mRNA expression of endothelin-1, only VPA significantly reduced expression of transforming growth factor-beta1. 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.
Bülow
Robin
R
Department of Medicine, Division of Gastroenterology, Medical Faculty, University of Rostock, E.-Heydemann-Str. 6, 18057 Rostock, Germany.
Fitzner
Brit
B
Sparmann
Gisela
G
Emmrich
Jörg
J
Liebe
Stefan
S
Jaster
Robert
R
D000199:Actins / Q000378:metabolism; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured; D003094:Collagen / Q000096:biosynthesis; D017931:DNA Primers; D019332:Endothelin-1 / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D005455:Fluorescent Antibody Technique; D056572:Histone Deacetylase Inhibitors; D008103:Liver Cirrhosis / Q000517:prevention & control*; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000187:drug effects*; D051381:Rats; D011917:Rats, Inbred Lew; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018808:Transcription Factor AP-1 / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000235:genetics
D000199:Actins; D017931:DNA Primers; D019332:Endothelin-1; D004791:Enzyme Inhibitors; D056572:Histone Deacetylase Inhibitors; D018808:Transcription Factor AP-1; D016212:Transforming Growth Factor beta; D003094:Collagen