Basic Research
Copyright ©2006 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Feb 14, 2006; 12(6): 896-901
Published online Feb 14, 2006. doi: 10.3748/wjg.v12.i6.896
Inhibitory effects of interferons on pancreatic stellate cell activation
Jan-Tido Baumert, Gisela Sparmann, Jörg Emmrich, Stefan Liebe, Robert Jaster
Jan-Tido Baumert, Gisela Sparmann, Jörg Emmrich, Stefan Liebe, Robert Jaster, Department of Medicine, Division of Gastroenterology, Medical Faculty, University of Rostock, E-Heydemann-Str. 6, 18057 Rostock, Germany
Supported by a grant from the Bundesministerium für Bildung und Forschung, No. FKZ 01ZZ0108
Correspondence to: Robert Jaster, MD, Department of Medicine, Division of Gastroenterology, Medical Faculty, University of Rostock, 18057 Rostock, Germany. jaster@med.uni-rostock.de
Telephone: +49-381-4947349 Fax: +49-381-4947482
Received: July 11, 2005
Revised: July 20, 2005
Accepted: July 28, 2005
Published online: February 14, 2006
Abstract

AIM: To analyze and to compare the effects of interferon (IFN)-α, IFN-β, and IFN-γ on pancreatic stellate cell (PSC) activation in vitro and to elucidate the molecular basis of IFN action.

METHODS: PSCs were isolated from rat’s pancreatic tissue, cultured and stimulated with recombinant rat IFNs. Cell proliferation and collagen synthesis were assessed by measuring the incorporation of 5-bromo-2’-deoxyuridine (BrdU) into DNA and [3H]-proline into acetic acid-soluble proteins, respectively. Apoptotic cells were determined by FACS analysis (sub-G1 peak method). Exhibition of the myofibroblastic PSC phenotype was monitored by immunoblot analysis of α-smooth muscle actin (α-SMA) expression. To assess the activation of signal transducer and activator of transcription (STAT), Western blots using phospho-STAT-specific antibodies were performed. In studies on STAT1 function, expression of the protein was inhibited by siRNA.

RESULTS: IFN-β and IFN-γ, but not IFN-α significantly diminished PSC proliferation and collagen synthesis. IFN-γ was the only IFN that clearly inhibited α-SMA expression. Under the experimental conditions used, no enhanced rate of apoptotic cell death was observed in response to any IFN treatment. IFN-β and IFN-γ induced a strong increase of STAT1 and STAT3 tyrosine phosphorylation, while the effect of IFN-α was much weaker. Inhibition of STAT1 expression with siRNA was associated with a significantly reduced growth-inhibitory effect of IFN-γ.

CONCLUSION: IFN-β and particularly IFN-γ display inhibitory effects on PSC activation in vitro and should be tested regarding their in vitro efficiency. Growth inhibition by IFN-γ action requires STAT1.

Keywords: Interferons; Pancreatic stellate cell; Apoptosis