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

Ann Rheum Dis. 2018 Mar;77(3):431-440. doi: 10.1136/annrheumdis-2017-212120. Epub 2017 Dec 19.

Abstract

Objectives: Systemic 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.

Methods: PEDF 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.

Results: PEDF 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.

Conclusions: Our 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.

Keywords: autoimmune diseases; fibroblasts; systemic sclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • 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*

Substances

  • Caveolin 1
  • Eye Proteins
  • Nerve Growth Factors
  • Serpins
  • Transforming Growth Factor beta
  • pigment epithelium-derived factor