Pro-fibrotic processes in human lung fibroblasts are driven by an autocrine/paracrine endothelinergic system
Article first published online: 20 DEC 2012
© 2012 The Authors. British Journal of Pharmacology © 2012 The British Pharmacological Society
British Journal of Pharmacology
Special Issue: Themed Section: Endothelin. Guest Editors: Anthony P Davenport and Matthias Barton
Volume 168, Issue 2, pages 471–487, January 2013
How to Cite
Ahmedat, A., Warnken, M., Seemann, W., Mohr, K., Kostenis, E., Juergens, U. and Racké, K. (2013), Pro-fibrotic processes in human lung fibroblasts are driven by an autocrine/paracrine endothelinergic system. British Journal of Pharmacology, 168: 471–487. doi: 10.1111/j.1476-5381.2012.02190.x
- Issue published online: 20 DEC 2012
- Article first published online: 20 DEC 2012
- Accepted manuscript online: 31 AUG 2012 05:01AM EST
- Manuscript Accepted: 8 AUG 2012
- Manuscript Revised: 27 JUL 2012
- Manuscript Received: 3 OCT 2011
- Research Grants from Actelion Pharmaceuticals Deutschland GmbH and Bonfor, Univ. Bonn
- ET-A and ET-B receptor;
- collagen synthesis;
- lung fibroblasts;
- airway remodelling;
- ERK MAPK;
- pertussis toxin;
- dynamic mass redistribution (DMR)
Background and Purpose
Since endothelin (ET) may act as pro-fibrotic mediator, expression and release of ET isoforms, their receptors and potential pro-fibrotic ET effects were studied in human lung fibroblasts.
MRC-5 and primary human lung fibroblasts (phLFb) were cultured. Expression of prepro-ET isoforms was determined by qPCR and release of ET-1 by elisa. ET receptor function was analysed by real-time measurement of dynamic mass redistribution (DMR). Incorporation of [3H]-thymidine was determined as measure of proliferation and that of [3H]-proline for collagen synthesis. Phospho-p42/44 MAP kinase was determined by Western blot.
ET-1 is the predominant ET in human lung fibroblasts (hLF), and TGF-β caused a further, selective and sustained up-regulation of ET-1 resulting in increased extracellular ET-1 accumulation. hLFb express mRNA encoding ET-A and ET-B receptors. Expression of both receptors was confirmed at protein level. ET-1 induced marked DMR signals, an effect that involved ET-A and ET-B receptors. Stimulatory effects of ET-1 on hLFb proliferation and collagen synthesis were mediated exclusively via ET-A receptors. ET-1, again via ET-A receptors, induced rapid activation of ERK MAPK, shown to be a crucial cellular signal in ET-1-induced collagen synthesis. ET-1-induced activation of ERK and collagen synthesis was, in contrast to corresponding effect of a muscarinic agonist, largely insensitive to pertussis toxin.
Conclusions and Implications
hLFb are endowed with all elements necessary to build a functional autocrine/paracrine endothelinergic system, which appears to drive pro-fibrotic airway and lung remodelling processes, effects for which only ET-A, but not ET-B receptors appear to be of significance.