title: Cell surface-bound collagenase-1 and focal substrate degradation stimulate the rear release of motile vascular smooth muscle cells.
abstract: To migrate in the vessel wall, smooth muscle cells (SMCs) must contend with abundant type I collagen. We investigated the mechanisms used by human SMCs to efficiently migrate on type I collagen, following stimulation with fibroblast growth factor-2 (FGF-2). FGF-2-stimulated migration was inhibited by a hydroxamic acid inhibitor of matrix metalloproteinases and by a neutralizing anti-collagenase-1 antibody. Moreover, migration speed of SMCs plated on mutant collagenase-resistant type I collagen was not increased by FGF-2. Time-lapse video analysis of unstimulated SMCs migrating on collagen revealed discrete phases of leading edge membrane extension and rear retraction, the latter often after rupture of an elongated tail. FGF-2 stimulation yielded a more synchronous, gliding motion with a collagenase-1-mediated decrease in tail ripping. Surface labeling of SMCs with biotin followed by immunoprecipitation revealed that a proportion of active collagenase-1, expressed in response to FGF-2, was bound to the plasma membrane. Pericellular collagen substrate cleavage was verified by immunostaining for neoepitopes generated by collagenase-1 action and was localized to discrete zones beneath the cell tail and the leading edge. These results identify a novel mechanism by which SMC migration on collagen is enhanced, whereby rear release from the substrate is orchestrated by the localized actions of membrane-bound collagenase-1.
authors.affiliation: John P. Robarts Research Institute (Vascular Biology Group), London Health Science Centre, Departments of Medicine (Cardiology), Medical Biophysics, and Biochemistry, University of Western Ontario, London, Ontario N6A 5K8, Canada.
authors.forename: S
authors.initials: S
authors.lastname: Li
authors.forename: L H
authors.initials: LH
authors.lastname: Chow
authors.forename: J G
authors.initials: JG
authors.lastname: Pickering
mesh_terms: D000818:Animals; D001710:Biotin / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D002465:Cell Movement; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D017364:Collagenases / Q000276:immunology / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D000939:Epitopes; D016222:Fibroblast Growth Factor 2 / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D061965:Matrix Metalloproteinase Inhibitors; D051379:Mice; D008856:Microscopy, Fluorescence; D018715:Microscopy, Video; D009130:Muscle, Smooth / Q000378:metabolism*; D009154:Mutation; D011233:Precipitin Tests; D011485:Protein Binding; D013895:Thoracic Arteries / Q000378:metabolism / Q000473:pathology; D013997:Time Factors
chemical_list: D000939:Epitopes; D006877:Hydroxamic Acids; D061965:Matrix Metalloproteinase Inhibitors; D016222:Fibroblast Growth Factor 2; D001710:Biotin; D003094:Collagen; D017364:Collagenases; C417249:collagenase 1