title: Contraction of collagen matrices mediated by alpha2beta1A and alpha(v)beta3 integrins.
abstract: The (beta)1-null fibroblastic cell line GD25 and its derivatives were studied to gain an understanding of the roles of (beta)1 and (beta)3 integrins in the initial (1-hour) contraction of collagen gels. Stable transfectants of GD25 cells expressing the (beta)1A splice variant of (beta)1 ((beta)1A-GD25) did not express (alpha)2(beta)1A and did not adhere to collagen. After transfection of (alpha)2 into (beta)1A-GD25 cells, the (alpha)2(beta)1A-GD25 transfectants contracted collagen gels in the presence of serum, whereas (beta)1A-GD25 cells did not. The GD25 parental cells, however, also contracted collagen gels. Collagen gel contraction by GD25 cells was blocked by antibodies to (alpha)v(beta)3 or a RGD-containing peptide, indicating that (alpha)v(beta)3 is the integrin responsible for mediation of contraction by GD25 cells. Collagen gel contraction by (alpha)2(beta)1A-GD25 cells was not inhibited by antibodies to (alpha)v(beta)3 or RGD-containing peptide, but was inhibited by anti-(alpha)2 antibody. Flow cytometry demonstrated negligible expression of (alpha)v(beta)3 by (beta)1A-GD25 and (alpha)2(beta)1A-GD25 cells when compared to GD25 cells. Platelet derived growth factor (PDGF) and sphingosine-1-phosphate (S1P) enabled gel contraction by (alpha)2(beta)1A-GD25 and GD25 cells, respectively, in the absence of serum. PDGF-stimulated contraction by (alpha)2(beta)1A-GD25 cells was attenuated in the presence of inhibitors of phosphatidylinositol-3-kinase whereas such inhibitors had no effect on S1P-stimulated contraction by GD25 cells. These experiments using the (beta)1-null GD25 cells and (beta)1A and (alpha)2(beta)1A transfectants demonstrate that (alpha)2(beta)1A and (alpha)v(beta)3 independently mediate collagen gel contraction and are regulated by different serum factors and signaling pathways.
authors.affiliation: Department of Biomolecular Chemistry and Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Cooke
authors.forename: T
authors.initials: T
authors.lastname: Sakai
authors.forename: D F
authors.initials: DF
authors.lastname: Mosher
mesh_terms: D002460:Cell Line; D003094:Collagen / Q000187:drug effects / Q000378:metabolism*; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D005782:Gels / Q000378:metabolism*; D016023:Integrins / Q000378:metabolism*; D008246:Lysophospholipids / Q000494:pharmacology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D038981:Receptors, Collagen; D019030:Receptors, Vitronectin / Q000378:metabolism*; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D014162:Transfection
chemical_list: D005782:Gels; D016023:Integrins; D008246:Lysophospholipids; D010982:Platelet-Derived Growth Factor; D038981:Receptors, Collagen; D019030:Receptors, Vitronectin; C060506:sphingosine 1-phosphate; D003094:Collagen; D013110:Sphingosine