title: Matrix metalloproteinase activity is necessary for thymosin beta 4 promotion of epithelial cell migration.
abstract: Studies from our laboratory provide substantial evidence that thymosin beta 4, (Tbeta(4)), an actin-sequestering protein, promotes corneal wound healing through its ability to stimulate epithelial cell migration. Matrix metalloproteinases (MMPs), which are expressed in a wide variety of tissues including the cornea, also play a key role in epithelial cell migration and wound healing. In this study we investigated the role of MMPs in Tbeta(4)-stimulated corneal epithelial cell migration. In Boyden chamber assays, XG076, an inhibitor of the conversion of pro- to active MMPs, had no effect on epithelial cell migration stimulated by exogenous activated MMP-1. However, in in vitro migration assays where the activation of pro-MMPs was blocked, XG076 significantly inhibited cell migration and wound healing in the presence or absence of Tbeta(4). GM6001, a broad-spectrum inhibitor of active MMPs and selective MMP inhibitors, also suppressed Tbeta(4)-stimulated cell migration. Tbeta(4) upregulated MMP-1 gene and protein expression in primary human corneal epithelial cells and in transformed human corneal epithelial cells following scrape wounding. From these results we conclude that MMP catalytic activity is necessary for Tbeta(4) promotion of epithelial cell migration. These novel findings are the first to demonstrate a functional link between the two.
authors.affiliation: Department of Ophthalmology, Kresge Eye Institute, Detroit, Michigan 48201, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Qiu
authors.forename: Michelle
authors.initials: M
authors.lastname: Kurpakus-Wheater
authors.forename: Gabriel
authors.initials: G
authors.lastname: Sosne
mesh_terms: D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D003315:Cornea / Q000166:cytology; D004847:Epithelial Cells / Q000378:metabolism*; D006801:Humans; D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases / Q000378:metabolism*; D013947:Thymosin / Q000378:metabolism*; D000099201:Thymosin beta(4)
chemical_list: D061965:Matrix Metalloproteinase Inhibitors; D020782:Matrix Metalloproteinases; D013947:Thymosin; D000099201:Thymosin beta(4)