Focal adhesion kinase and reactive oxygen species contribute to the persistent fibrotic phenotype of lesional scleroderma fibroblasts

Rheumatology (Oxford). 2012 Dec;51(12):2146-54. doi: 10.1093/rheumatology/kes234. Epub 2012 Sep 12.

Abstract

Objective: Fibrotic diseases such as SSc (systemic sclerosis, scleroderma) are characterized by the abnormal presence of the myofibroblast, a specialized type of fibroblast that overexpresses the highly contractile protein α-smooth muscle actin. Myofibroblasts display excessive adhesive properties and hence exert a potent mechanical force. We aim to identify the precise contribution of adhesive signalling, which requires integrin-mediated activation of focal adhesion kinase (FAK)/src, to fibrogenic gene expression in normal and fibrotic SSc fibroblasts.

Methods: We subject either FAK wild-type and knockout fibroblasts or normal and SSc fibroblasts treated with FAK/src inhibitors to real-time polymerase chain, western blot, cell migration and collagen gel contraction analyses.

Results: FAK operates downstream of both integrin β1 and reactive oxygen species (ROS) to promote the expression of genes involved in matrix production and remodelling, including CCN2, α-smooth muscle actin and type I collagen. Blocking either FAK/src with PP2 or ROS with N-acetyl cysteine alleviates the elevated contractile and migratory capability of lesional SSc dermal fibroblasts.

Conclusions: Excessive adhesive signalling is intimately involved with the fibrotic phenotype of lesional SSc fibroblasts; blocking adhesive signalling or ROS generation may be beneficial in controlling the fibrosis observed in SSc.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cells, Cultured
  • Female
  • Focal Adhesion Protein-Tyrosine Kinases / physiology*
  • Humans
  • Male
  • Mice
  • Myofibroblasts / physiology*
  • Phosphorylation / physiology
  • Protein Kinase Inhibitors / pharmacology
  • Pyrimidines / pharmacology
  • RNA, Messenger / metabolism
  • Reactive Oxygen Species / metabolism*
  • Scleroderma, Systemic / etiology*
  • Scleroderma, Systemic / metabolism
  • Signal Transduction

Substances

  • AG 1879
  • Protein Kinase Inhibitors
  • Pyrimidines
  • RNA, Messenger
  • Reactive Oxygen Species
  • Focal Adhesion Protein-Tyrosine Kinases