Fibrogenesis Tissue Repair. 2014 Oct 02;7:14. doi: 10.1186/1755-1536-7-14. eCollection 2014.
Secreted frizzled related proteins inhibit fibrosis in vitro but appear redundant in vivo.
Fibrogenesis & tissue repair
Ellen De Langhe, Carolina Aznar-Lopez, Vanessa De Vooght, Jeroen A Vanoirbeek, Frank P Luyten, Rik Ju Lories
Affiliations
Affiliations
- Department of Development and Regeneration, Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium ; Division of Rheumatology, University Hospitals Leuven, Leuven, Belgium.
- Department of Development and Regeneration, Laboratory of Tissue Homeostasis and Disease, Skeletal Biology and Engineering Research Center, KU Leuven, Leuven, Belgium.
- Department of Public Health, Experimental Toxicology Unit, KU Leuven, Leuven, Belgium.
PMID: 25317206
PMCID: PMC4196208 DOI: 10.1186/1755-1536-7-14
Abstract
BACKGROUND: The pathogenesis of pulmonary fibrosis remains poorly understood. The Wnt signaling pathway regulates fibrogenesis in different organs. Here, we studied the role of two extracellular Wnt antagonists, secreted frizzled-related protein-1 (SFRP1) and frizzled-related protein (FRZB) on lung fibrosis in vitro and in vivo. For this purpose, we used an alveolar epithelial cell line and a lung fibroblast cell line, and the bleomycin-induced lung fibrosis model, respectively.
RESULTS: During the course of bleomycin-induced lung fibrosis, Sfrp1 and Frzb expression are upregulated. Expression of Sfrp1 appears much higher than that of Frzb. In vitro, recombinant SFRP1, but not FRZB, counteracts the transforming growth factor β1 (TGFβ1)-induced upregulation of type I collagen expression both in pulmonary epithelial cells and fibroblasts. Both SFRP1 and FRZB inhibit the TGFβ1-induced increase of active β-catenin, but do not influence the TGFβ1-induced phosphorylation levels of SMAD3, positioning Wnt signaling activity downstream of the active TGFβ signal in lung fibroblasts, but not in alveolar epithelial cells. In vivo, Sfrp1 (-/-) and Frzb (-/-) mice showed identical responses to bleomycin in the lung compared to wild-type controls.
CONCLUSIONS: Although SFRP1 counteracts the effect of TGFβ1 in pulmonary cells in vitro; loss of neither SFRP1 nor FRZB alters fibrotic outcomes in the lungs in vivo. The lack of in vivo effect in the absence of specific SFRPs suggests functional redundancy within this family of Wnt antagonists.
Keywords: Bleomycin; Pulmonary fibrosis; Secreted frizzled related proteins; Skin fibrosis; Transforming growth factor-beta; WNT signaling
References
- Nat Cell Biol. 2009 Jan;11(1):13 - PubMed
- J Cell Biol. 2011 May 2;193(3):551-64 - PubMed
- J Clin Invest. 2008 Oct;118(10):3279-90 - PubMed
- PLoS One. 2012;7(8):e43123 - PubMed
- Am J Pathol. 2010 Aug;177(2):598-607 - PubMed
- Am J Respir Cell Mol Biol. 2010 Jan;42(1):96-104 - PubMed
- Cell. 1997 Mar 21;88(6):747-56 - PubMed
- Cell. 2012 Jun 8;149(6):1192-205 - PubMed
- Arch Biochem Biophys. 1961 May;93:440-7 - PubMed
- Am J Respir Cell Mol Biol. 2010 Jan;42(1):21-31 - PubMed
- Eur Respir J. 2013 May;41(5):1207-18 - PubMed
- J Clin Invest. 2009 Apr;119(4):772-87 - PubMed
- Nat Commun. 2012 Mar 13;3:735 - PubMed
- Proc Natl Acad Sci U S A. 2010 Aug 10;107(32):14309-14 - PubMed
- J Cell Sci. 2008 Mar 15;121(Pt 6):737-46 - PubMed
- PLoS One. 2008 May 14;3(5):e2142 - PubMed
- Am J Respir Cell Mol Biol. 2011 Nov;45(5):915-22 - PubMed
- J Clin Pathol. 1988 Apr;41(4):467-70 - PubMed
- Ann Rheum Dis. 2011 Dec;70(12):2191-8 - PubMed
- Cell. 2012 Jun 8;149(6):1245-56 - PubMed
- PLoS Med. 2008 Mar 4;5(3):e62 - PubMed
- Development. 2009 Dec;136(24):4083-8 - PubMed
- J Biol Chem. 1996 Oct 18;271(42):26131-7 - PubMed
- Am J Respir Crit Care Med. 2011 Feb 15;183(4):431-40 - PubMed
- Circ Res. 2010 Jun 25;106(12):1798-806 - PubMed
- Dev Biol. 2008 May 1;317(1):161-73 - PubMed
- Cell. 1997 Mar 21;88(6):757-66 - PubMed
- Dev Growth Differ. 2011 Oct;53(8):911-23 - PubMed
- Am J Pathol. 2003 May;162(5):1495-502 - PubMed
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