Surface proteome analysis identifies platelet derived growth factor receptor-alpha as a critical mediator of transforming growth factor-beta-induced collagen secretion

• Published in: The international journal of biochemistry & cell biology 2016-05, Vol.74, p.44-59
• Main Authors: Heinzelmann, Katharina, Noskovičová, Nina, Merl-Pham, Juliane, Preissler, Gerhard, Winter, Hauke, Lindner, Michael, Hatz, Rudolf, Hauck, Stefanie M., Behr, Jürgen, Eickelberg, Oliver
• Format: Article
• Language: English
• Subjects: Antigens, Surface - metabolism; Blotting, Western; Cell signaling; Cell surface; Collagen - secretion; Electrophoresis, Polyacrylamide Gel; fibroblasts; Fibroblasts - drug effects; Fibroblasts - metabolism; Gene Expression Regulation - drug effects; Humans; Mass spectrometry; Proteome; Pulmonary fibrosis; Receptors, Platelet-Derived Growth Factor - genetics; Receptors, Platelet-Derived Growth Factor - metabolism; Surface proteome; Transforming Growth Factor beta - metabolism; Transforming Growth Factor beta - pharmacology
• ISSN: 1357-2725; 1878-5875
• DOI: 10.1016/j.biocel.2016.02.013

•TGF-β significantly regulates 213 proteins of the human fibroblast surface proteome.•PDGFRα expression and the number of positive cells is down-regulated by TGF-β.•TGF-β induces PDGF signaling by phosphorylation of Akt dependent on PDGFR expression.•Decreased PDGFRα levels correlate with increased expression of PDGFRβ, αSMA and collagen type V. Fibroblasts are extracellular matrix-producing cells in the lung. Fibroblast activation by transforming growth factor-beta leads to myofibroblast-differentiation and increased extracellular matrix deposition, a hallmark of pulmonary fibrosis. While fibroblast function with respect to migration, invasion, and extracellular matrix deposition has been well-explored, little is known about the surface proteome of lung fibroblasts in general and its specific response to fibrogenic growth factors, in particular transforming growth factor-beta. We thus performed a cell-surface proteome analysis of primary human lung fibroblasts in presence/absence of transforming growth factor-beta, followed by characterization of our findings using FACS analysis, Western blot, and siRNA-mediated knockdown experiments. We identified 213 surface proteins significantly regulated by transforming growth factor-beta, platelet derived growth factor receptor-alpha being one of the top down-regulated proteins. Transforming growth factor beta-induced downregulation of platelet derived growth factor receptor-alpha induced upregulation of platelet derived growth factor receptor-beta expression and phosphorylation of Akt, a downstream target of platelet derived growth factor signaling. Importantly, collagen type V expression and secretion was strongly increased after forced knockdown of platelet derived growth factor receptor-alpha, an effect that was potentiated by transforming growth factor-beta. We therefore show previously underappreciated cross-talk of transforming growth factor-beta and platelet derived growth factor signaling in human lung fibroblasts, resulting in increased extracellular matrix deposition in a platelet derived growth factor receptor-alpha dependent manner. These findings are of particular importance for the treatment of lung fibrosis patients with high pulmonary transforming growth factor-beta activity.