Scleroderma fibroblasts suppress angiogenesis via TGF-β/caveolin-1 dependent secretion of pigment epithelium-derived factor

• Published in: Annals of the rheumatic diseases Vol. 77; no. 3; pp. 431 - 440
• Main Authors: Liakouli, Vasiliki, Elies, Jacobo, El-Sherbiny, Yasser Mohamed, Scarcia, Margherita, Grant, Gary, Abignano, Giuseppina, Derrett-Smith, Emma C, Esteves, Filomena, Cipriani, Paola, Emery, Paul, Denton, Christopher P, Giacomelli, Roberto, Mavria, Georgia, Del Galdo, Francesco
• Format: Journal Article
• Language: English
• Published: England BMJ Publishing Group 01.03.2018
• Series: Extended report
• Subjects: Animals; Basic and Translational Research; Caveolin 1 - metabolism; Cells, Cultured; Endothelial Cells - metabolism; Eye Proteins - metabolism; Female; Fibroblasts - metabolism; Humans; Immunohistochemistry; Male; Mice; Mice, Transgenic; Neovascularization, Pathologic - metabolism; Nerve Growth Factors - metabolism; Real-Time Polymerase Chain Reaction; Scleroderma, Systemic - metabolism; Scleroderma, Systemic - pathology; Serpins - metabolism; Skin - pathology; Transforming Growth Factor beta - metabolism; autoimmune diseases; fibroblasts; systemic sclerosis
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/annrheumdis-2017-212120

ObjectivesSystemic sclerosis (SSc) is characterised by tissue fibrosis and vasculopathy with defective angiogenesis. Transforming growth factor beta (TGF-β) plays a major role in tissue fibrosis, including downregulation of caveolin-1 (Cav-1); however, its role in defective angiogenesis is less clear. Pigment epithelium-derived factor (PEDF), a major antiangiogenic factor, is abundantly secreted by SSc fibroblasts. Here, we investigated the effect of TGF-β and Cav-1 on PEDF expression and the role of PEDF in the ability of SSc fibroblasts to modulate angiogenesis.MethodsPEDF and Cav-1 expression in fibroblasts and endothelial cells were evaluated by means of immunohistochemistry on human and mouse skin biopsies. PEDF and Cav-1 were silenced in cultured SSc and control fibroblasts using lentiviral short-hairpin RNAs. Organotypic fibroblast–endothelial cell co-cultures and matrigel assays were employed to assess angiogenesis.ResultsPEDF is highly expressed in myofibroblasts and reticular fibroblasts with low Cav-1 expression in SSc skin biopsies, and it is induced by TGF-β in vitro. SSc fibroblasts suppress angiogenesis in an organotypic model. This model is reproduced by silencing Cav-1 in normal dermal fibroblasts. Conversely, silencing PEDF in SSc fibroblasts rescues their antiangiogenic phenotype. Consistently, transgenic mice with TGF-β receptor hyperactivation show lower Cav-1 and higher PEDF expression levels in skin biopsies accompanied by reduced blood vessel density.ConclusionsOur data reveal a new pathway by which TGF-β suppresses angiogenesis in SSc, through decreased fibroblast Cav-1 expression and subsequent PEDF secretion. This pathway may present a promising target for new therapeutic interventions in SSc.