title: Integrin-linked kinase is required for TGF-β1 induction of dermal myofibroblast differentiation.
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.
authors.affiliation: Department of Physiology and Pharmacology, Children's Health Research Institute and Lawson Health Research Institute, University of Western Ontario, London, Ontario, Canada.
authors.forename: Linda
authors.initials: L
authors.lastname: Vi
authors.forename: Cristina
authors.initials: C
authors.lastname: de Lasa
authors.forename: Gianni M
authors.initials: GM
authors.lastname: DiGuglielmo
authors.forename: Lina
authors.initials: L
authors.lastname: Dagnino
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D003094:Collagen / Q000378:metabolism; D020405:Dermis / Q000166:cytology* / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D051379:Mice; D023421:Models, Animal; D058628:Myofibroblasts / Q000166:cytology* / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000172:deficiency / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051899:Smad2 Protein / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D053773:Transforming Growth Factor beta1 / Q000235:genetics / Q000378:metabolism*; D000099200:Scaffold Protein ILK
chemical_list: D000199:Actins; D003094:Collagen; D017346:Protein Serine-Threonine Kinases; D051899:Smad2 Protein; D051900:Smad3 Protein; D053773:Transforming Growth Factor beta1; D000099200:Scaffold Protein ILK; C497783:Smad2 protein, mouse; C497791:Smad3 protein, mouse