title: Surface proteome analysis identifies platelet derived growth factor receptor-alpha as a critical mediator of transforming growth factor-beta-induced collagen secretion.
abstract: 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.
authors.affiliation: Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany.
authors.forename: Katharina
authors.initials: K
authors.lastname: Heinzelmann
authors.affiliation: Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Noskovičová
authors.affiliation: Research Unit Protein Science/Helmholtz Zentrum München, Neuherberg, Germany.
authors.forename: Juliane
authors.initials: J
authors.lastname: Merl-Pham
authors.affiliation: Thoraxchirurgisches Zentrum, Klinik für Allgemeine-, Viszeral-, Transplantations-, Gefäß- und Thoraxchirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Preissler
authors.affiliation: Thoraxchirurgisches Zentrum, Klinik für Allgemeine-, Viszeral-, Transplantations-, Gefäß- und Thoraxchirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Hauke
authors.initials: H
authors.lastname: Winter
authors.affiliation: Asklepios Fachkliniken München-Gauting, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Lindner
authors.affiliation: Thoraxchirurgisches Zentrum, Klinik für Allgemeine-, Viszeral-, Transplantations-, Gefäß- und Thoraxchirurgie, Klinikum Großhadern, Ludwig-Maximilians-Universität, Munich, Germany; Asklepios Fachkliniken München-Gauting, Munich, Germany.
authors.forename: Rudolf
authors.initials: R
authors.lastname: Hatz
authors.affiliation: Research Unit Protein Science/Helmholtz Zentrum München, Neuherberg, Germany.
authors.forename: Stefanie M
authors.initials: SM
authors.lastname: Hauck
authors.affiliation: Asklepios Fachkliniken München-Gauting, Munich, Germany; Medizinische Klinik und Poliklinik V, Klinikum der Ludwig-Maximilians-Universität, Munich, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Behr
authors.affiliation: Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany. Electronic address: oliver.eickelberg@helmholtz-muenchen.de.
authors.forename: Oliver
authors.initials: O
authors.lastname: Eickelberg
mesh_terms: D000954:Antigens, Surface / Q000378:metabolism; D015153:Blotting, Western; D003094:Collagen / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D020543:Proteome; D017479:Receptors, Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000954:Antigens, Surface; D020543:Proteome; D016212:Transforming Growth Factor beta; D003094:Collagen; D017479:Receptors, Platelet-Derived Growth Factor
keywords: Cell signaling; Cell surface; Mass spectrometry; Pulmonary fibrosis; Surface proteome; fibroblasts