Original Articles
Copyright ©2009 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Sep 7, 2009; 15(33): 4143-4149
Published online Sep 7, 2009. doi: 10.3748/wjg.15.4143
Molecular determinants of the profibrogenic effects of endothelin-1 in pancreatic stellate cells
Anika Jonitz, Brit Fitzner, Robert Jaster
Anika Jonitz, Brit Fitzner, Robert Jaster, Department of Medicine II, Division of Gastroenterology, Medical Faculty, University of Rostock, E.-Heydemann-Str. 6, 18057 Rostock, Germany
Author contributions: Fitzner B and Jaster R designed the study; Jonitz A and Fitzner B performed the experiments; all authors analyzed the data; Jaster R wrote the manuscript.
Supported by A grant from the Deutsche Forschungsgemeinschaft (Ja 819/3-2)
Correspondence to: Robert Jaster, MD, Department of Medicine II, Division of Gastroenterology, Medical Faculty, University of Rostock, E.-Heydemann-Str. 6, 18057 Rostock, Germany. jaster@med.uni-rostock.de
Telephone: +49-381-4947349 Fax: +49-381-4947482
Received: June 30, 2009
Revised: July 27, 2009
Accepted: August 3, 2009
Published online: September 7, 2009

AIM: To gain molecular insights into the expression and functions of endothelin-1 (ET-1) in pancreatic stellate cells (PSC).

METHODS: PSCs were isolated from rat pancreas tissue, cultured, and stimulated with ET-1 or other extracellular mediators. Cell proliferation was assessed by measuring the incorporation of 5-bromo-2’-deoxyuridine into DNA and cell migration was studied in a transwell chamber assay. Gene expression at the level of mRNA was quantified by real-time polymerase chain reaction. Expression and phosphorylation of proteins were monitored by immunoblotting, applying an infrared imaging technology. ET-1 levels in cell culture supernatants were determined by an enzyme immunometric assay. To study DNA binding of individual transcription factors, electrophoretic mobility shift assays were performed.

RESULTS: Among several mediators tested, transforming growth factor-β1 and tumour necrosis factor-α displayed the strongest stimulatory effects on ET-1 secretion. The cytokines induced binding of Smad3 and NF-κB, respectively, to oligonucleotides derived from the ET-1 promoter, implicating both transcription factors in the induction of ET-1 gene expression. In accordance with previous studies, ET-1 was found to stimulate migration but not proliferation of PSC. Stimulation of ET-1 receptors led to the activation of two distinct mitogen-activated protein kinases, p38 and extracellular signal-regulated kinases (ERK)1/2, as well as the transcription factor activator protein-1. At the mRNA level, enhanced expression of the PSC activation marker, α-smooth muscle actin and two proinflammatory cytokines, interleukin (IL)-1β and IL-6, was observed.

CONCLUSION: This study provides novel lines of evidence for profibrogenic and proinflammatory actions of ET-1 in the pancreas, encouraging further studies with ET-1 inhibitors in chronic pancreatitis.

Keywords: Chronic pancreatitis, Endothelin-1, Fibrosis, Pancreatic stellate cells