title: Alteration in cell morphology triggers transforming growth factor-beta 1, collagenase, and tissue inhibitor of metalloproteinases-I expression in normal and hypertrophic scar fibroblasts.
abstract: Using immunocytochemistry and Northern blot analysis, we investigated the role of cell morphology and reorganization of the cytoskeleton in the expression of transforming growth factor-beta 1 (TGF-beta 1) in human dermal fibroblasts. Disruption of the cytoskeleton was induced by three different agents--trypsin, ethyl-eneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), or cytochalasin--and was confirmed by staining with rhodamine-labeled phalloidin. Immunocytochemical staining with antibodies specific for TGF-beta 1 revealed a cell-shape-related induction of TGF-beta 1. Northern blot analysis of total RNA showed a significant increase in the expression of TGF-beta 1 mRNA as early as 4 h and peaking at 12 h after disruption of the cytoskeleton. Quantitative analysis of TGF-beta 1 mRNA expression at 4 h after treatment with trypsin, EGTA, or cytochalasin C showed increases of 2.6-, 3.3-, and 2.6-fold, respectively. Disruption of the cytoskeleton by trypsin, EGTA, or cytochalasin C increased mRNA for collagenase by 3.8-fold, 2.3-fold, or 2.5-fold, respectively. The expression of mRNA for tissue inhibitor of metalloproteinases I (TIMP-I) also showed a 3.2-fold increase by trypsin, a 3.6-fold increase by EGTA, and a 2.5-fold increase by cytochalasin C. Cell-shape-related induction of TGF-beta 1, collagenase, and TIMP-I genes appears to be selective, as the levels of mRNA for fibronectin and type I procollagen were not significantly altered. These data suggest that gene expression of TGF-beta 1, collagenase, and TIMP-I is governed by the status of the cytoskeleton microfilament organization, which may be a mechanism of gene regulation during cell division, migration, and differentiation, events fundamental to wound healing.
authors.affiliation: Department of Surgery, University of Alberta, Edmonton, Canada.
authors.forename: M
authors.initials: M
authors.lastname: Varedi
authors.forename: E E
authors.initials: EE
authors.lastname: Tredget
authors.forename: P G
authors.initials: PG
authors.lastname: Scott
authors.forename: Y J
authors.initials: YJ
authors.lastname: Shen
authors.forename: A
authors.initials: A
authors.lastname: Ghahary
mesh_terms: D000199:Actins / Q000737:chemistry; D015152:Blotting, Northern; D002921:Cicatrix / Q000473:pathology* / Q000503:physiopathology; D017364:Collagenases / Q000235:genetics / Q000502:physiology; D003599:Cytoskeleton / Q000473:pathology; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology*; D006023:Glycoproteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D006984:Hypertrophy / Q000378:metabolism; D007150:Immunohistochemistry; D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger / Q000032:analysis; D013194:Staining and Labeling; D019714:Tissue Inhibitor of Metalloproteinases; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000502:physiology*
chemical_list: D000199:Actins; D006023:Glycoproteins; D061965:Matrix Metalloproteinase Inhibitors; D012333:RNA, Messenger; D019714:Tissue Inhibitor of Metalloproteinases; D016212:Transforming Growth Factor beta; D017364:Collagenases