title: Tendon cells produce gelatinases in response to type I collagen attachment.
abstract: Cells that carry out wound healing must be able to perform catabolic as well as anabolic functions. As the tendon is a tissue rich in extracellular matrix (ECM) proteins, we hypothesized that cells which participate in tendon healing should be able to produce proteases that would allow the remodeling of such a tissue. To this end, we assessed the ability of endotenon cells isolated from canine flexor digitorum profundus tendon and from surrounding parietal sheath to produce the gelatinases MMP-2 and MMP-9. Endotenon and sheath cells cultured in vitro on polystyrene produced small amounts of MMP-2 and MMP-9 was not detectable. When cultured on polystyrene coated with type I collagen, the cells upregulated MMP-2 production and MMP-9 production was induced. No other ECM protein elicited this response nor did other cell lines respond in this way after attachment to type I collagen. The two gelatinases were identified by immunological methods, ability to bind gelatin, size, metal ion requirement, serine protease inhibitor insensitivity, and APMA activation. For cells grown on collagen-coated plastic, gelatinase upregulation was proportional to the amount of ligand present until saturation was reached. For any group of fresh tendon cells, MMP-2 and MMP-9 upregulation was greater in a three dimensional collagen gel than the highest response from the same group under two dimensional culture conditions. Attachment of the cells to type I collagen increased the ratio of active to inactive MMP-2. Dexamethasone inhibited the upregulation of both MMP-2 and MMP-9. These results show that ECM proteins can influence both the production and the state of activation of these matrix metalloproteinases.
authors.affiliation: Washington University School of Medicine, Department of Orthopaedic Surgery, One Barnes-Jewish Hospital Plaza, Suite 11300, West Pavilion, St. Louis, MO 63110, USA. tritty@cellbio.wustl.edu
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Ritty
authors.forename: Jeremy
authors.initials: J
authors.lastname: Herzog
mesh_terms: D016475:3T3 Cells; D000818:Animals; D016466:CHO Cells; D019556:COS Cells; D002417:Cattle; D002448:Cell Adhesion / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism* / Q000494:pharmacology; D006224:Cricetinae; D004789:Enzyme Activation / Q000187:drug effects; D005109:Extracellular Matrix / Q000201:enzymology; D006801:Humans; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D051379:Mice; D012516:Osteosarcoma; D013710:Tendons / Q000166:cytology / Q000201:enzymology*; D014407:Tumor Cells, Cultured
chemical_list: D024042:Collagen Type I; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9