title: Interaction of keratinocytes and fibroblasts modulates the expression of matrix metalloproteinases-2 and -9 and their inhibitors.
abstract: Disruption of epidermal-mesenchymal communication due to a delay in epithelialization, increases the frequency of developing fibrotic conditions in skin. As matrix metalloproteinases-2 (MMP-2) and -9 (MMP-9) are two key enzymes involved in wound healing and tissue remodeling, here we examined the efficacy of keratinocyte-fibroblast interaction on modulation of these enzymes and their inhibitors. The conditioned media derived from keratinocytes and fibroblasts grown in upper and lower chambers of a co-culture system, respectively, were analyzed for MMP-2 and -9. Keratinocyte or fibroblast conditioned medium (FCM) was used as a control. Gelatinolytic activity analyzed by zymography showed that keratinocytes mainly express MMP-9 and to a lesser extent MMP-2; while fibroblasts express only MMP-2. In a co-culture system, the activities of both MMP-2 and MMP-9 markedly increased in conditioned media collected from bottom chambers. These findings were consistent with the level of MMP-2 and MMP-9 measured by Western blot. Using the same experimental setting, the levels of tissue inhibitors of MMPs (TIMPs) secreted by keratinocytes and fibroblasts grown in the same co-culture system were also evaluated. Western blot showed that fibroblasts secrete only TIMP-1 and TIMP-2 whose levels were increased by co-culturing fibroblasts with keratinocytes. In contrary the level of TIMP-3, which was mainly expressed by keratinocytes, increased by co-culturing these cells with fibroblasts. In conclusion, interaction of fibroblast-keratinocyte modulates the levels of MMP-2 and -9 and their inhibitors produced by these cells and this interaction may be critical for a better healing quality at a late stage of the wound healing process.
authors.affiliation: Department of Pharmacology, Cardiovascular Research Group, University of Alberta, Edmonton, Alberta, Canada.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Sawicki
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Marcoux
authors.forename: Kourosh
authors.initials: K
authors.lastname: Sarkhosh
authors.forename: Edward E
authors.initials: EE
authors.lastname: Tredget
authors.forename: Aziz
authors.initials: A
authors.lastname: Ghahary
mesh_terms: D002450:Cell Communication; D002478:Cells, Cultured; D018920:Coculture Techniques; D017077:Culture Media, Conditioned; D005347:Fibroblasts / Q000201:enzymology*; D006801:Humans; D015603:Keratinocytes / Q000201:enzymology*; D020778:Matrix Metalloproteinase 2 / Q000032:analysis / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000032:analysis / Q000378:metabolism*; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000032:analysis / Q000378:metabolism; D019716:Tissue Inhibitor of Metalloproteinase-2 / Q000032:analysis / Q000378:metabolism; D014945:Wound Healing / Q000502:physiology
chemical_list: D017077:Culture Media, Conditioned; D019715:Tissue Inhibitor of Metalloproteinase-1; D019716:Tissue Inhibitor of Metalloproteinase-2; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9