Systemic sclerosis fibroblasts inhibit in vitro angiogenesis by MMP-12-dependent cleavage of the endothelial cell urokinase receptor

J Pathol. 2006 Oct;210(2):240-8. doi: 10.1002/path.2048.


Failure of endothelial cells to develop new vessels in response to hypoxia is a distinctive feature of systemic sclerosis (SSc) in the avascular phase. We have previously shown that SSc endothelial cells over-express matrix metalloproteinase-12 (MMP-12), which blocks angiogenesis by cleavage of the endothelial urokinase-type plasminogen activator receptor (uPAR). In the present study, we have investigated whether over-expression of MMP-12 and of angiostatic factors, or hypo-expression of angiogenic factors by SSc fibroblasts, contributes to impaired angiogenesis in SSc. Dermal fibroblasts were isolated from healthy subjects (N-Fb) and patients with diffuse SSc (SSc-Fb). Angiogenesis of target normal human microvascular endothelial cells (H-MVECs) was assayed by Matrigel invasion, cell proliferation, and capillary morphogenesis. uPAR cleavage and MMP-12 activity were evaluated by western blotting. We show that the over-expression of MMP-12 by SSc-Fb determines uPAR cleavage in H-MVECs. Conditioned medium from SSc-Fb impaired H-MVEC proliferation, invasion, and capillary morphogenesis. Anti-MMP-12 antibodies restored such impairment. Altered expression of angiostatic/angiogenic factors, including transforming growth factor beta1, did not account for SSc-Fb-dependent impairment of angiogenesis. The over-expression of MMP-12 by both SSc-Fb and SSc endothelial cells indicates that MMP-12 over-production may have a critical pathogenic role in SSc-associated vascular alterations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Proliferation
  • Cells, Cultured
  • Child
  • Child, Preschool
  • Collagen
  • Culture Media, Conditioned
  • Drug Combinations
  • Endothelium, Vascular / metabolism
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Fibroblasts / physiology*
  • Humans
  • Laminin
  • Male
  • Matrix Metalloproteinase 12 / biosynthesis
  • Matrix Metalloproteinase 12 / physiology*
  • Neovascularization, Physiologic*
  • Proteoglycans
  • Receptors, Cell Surface / metabolism*
  • Receptors, Urokinase Plasminogen Activator
  • Reverse Transcriptase Polymerase Chain Reaction / methods
  • Scleroderma, Systemic / metabolism
  • Scleroderma, Systemic / physiopathology*


  • Culture Media, Conditioned
  • Drug Combinations
  • Laminin
  • PLAUR protein, human
  • Proteoglycans
  • Receptors, Cell Surface
  • Receptors, Urokinase Plasminogen Activator
  • matrigel
  • Collagen
  • Matrix Metalloproteinase 12