Integrin-linked kinase is required for TGF-β1 induction of dermal myofibroblast differentiation

J Invest Dermatol. 2011 Mar;131(3):586-93. doi: 10.1038/jid.2010.362. Epub 2010 Dec 9.

Abstract

Cutaneous repair after injury requires activation of resident dermal fibroblasts and their transition to myofibroblasts. The key stimuli for myofibroblast formation are activation of transforming growth factor-β (TGF-β) receptors and mechanotransduction mediated by integrins and associated proteins. We investigated the role of integrin-linked kinase (ILK) in TGF-β1 induction of dermal fibroblast transition to myofibroblasts. ILK-deficient fibroblasts treated with TGF-β1 exhibited attenuation of Smad 2 and 3 phosphorylation, accompanied by impaired transcriptional activation of Smad targets, such as α-smooth muscle actin. These alterations were not limited to Smad-associated TGF-β1 responses, as stimulation of noncanonical mitogen-activated protein kinase pathways by this growth factor was also diminished in the absence of ILK. ILK-deficient fibroblasts exhibited abnormalities in the actin cytoskeleton, and did not form supermature focal adhesions or contractile F-actin stress fibers, indicating a severe impairment in their capacity to differentiate into myofibroblasts. These defects extended to the inability of cells to contract extracellular matrices when embedded in collagen lattices. We conclude that ILK is necessary to transduce signals implicated in the transition of dermal fibroblasts to myofibroblasts originating from matrix substrates and TGF-β1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Cell Differentiation / physiology*
  • Cell Movement / physiology
  • Cell Proliferation
  • Cells, Cultured
  • Collagen / metabolism
  • Dermis / cytology*
  • Dermis / metabolism*
  • Gene Expression Regulation / physiology
  • Mice
  • Models, Animal
  • Myofibroblasts / cytology*
  • Myofibroblasts / metabolism*
  • Protein-Serine-Threonine Kinases / deficiency
  • Protein-Serine-Threonine Kinases / metabolism*
  • Signal Transduction / physiology
  • Smad2 Protein / metabolism
  • Smad3 Protein / metabolism
  • Transforming Growth Factor beta1 / genetics
  • Transforming Growth Factor beta1 / metabolism*

Substances

  • Actins
  • Smad2 Protein
  • Smad2 protein, mouse
  • Smad3 Protein
  • Smad3 protein, mouse
  • Transforming Growth Factor beta1
  • Collagen
  • integrin-linked kinase
  • Protein-Serine-Threonine Kinases