The objective of the proposed research is to elucidate the enzymatic mechanisms by which the extracellular matrix of human articular cartilage is degraded. Particular attention will be given to endogenous enzymatic mechanisms under the control of the chondrocytes. Proteolytic enzymes will be studied with respect to the digestion of collagen and proteoglycan. The proteases of interest appear to be metalloproteases that act at physiological pH. They occur as active and latent forms; the latent forms can be activated with trypsin or mercurials. In the first stages of the research, efforts will be directed to purifying the neutral metalloproteases that degrade proteoglycan and to characterizing them with respect to molecular weight, metal ion requirements for function and stability, activation mechanisms, substrate specificity and action on proteoglycan. An inhibitor of metalloproteases has been detected in cartilage and this will also be purified and characterized. Collagenase, gelatinase and the major enzyme activities will be quantitated in osteoarthritic human cartilage by means of direct assay of tissue homogenates involving endogenous substrates, and by extraction and assay of the proteases on defined substrates. The results will be correlated with histochemical evaluation of the disease. Similar studies will be performed in the Pond-Nuki model of osteoarthritis in the dog. Finally, organ cultures of dog cartilage will be used to study the resorption of the matrix induced by macrofactors and to test potential inhibitors and therapeutic agents that might block matrix breakdown. This work on cartilage proteases and their regulation will be of considerable importance in understanding the pathogenesis of joint disease, since it will define the nature of the proteases actually within the cartilage, and possibly arising from the chondrocytes. The knowledge of enzyme properties and specificities may open the way to rational treatment of joint disease. This information may also be of value in understanding cartilage remodeling, calcification, fracture healing, bone remodeling and osteoporosis.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
5R01AR016940-15
Application #
3154926
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1978-06-01
Project End
1988-05-31
Budget Start
1987-06-01
Budget End
1988-05-31
Support Year
15
Fiscal Year
1987
Total Cost
Indirect Cost
Name
University of Miami School of Medicine
Department
Type
Schools of Medicine
DUNS #
City
Miami
State
FL
Country
United States
Zip Code
33101
Yu, W H; Woessner Jr, J F (2001) Heparin-enhanced zymographic detection of matrilysin and collagenases. Anal Biochem 293:38-42
Woessner Jr, J F (2001) MMPs and TIMPs. An historical perspective. Methods Mol Biol 151:1-23
Yu, W H; Woessner Jr, J F (2000) Heparan sulfate proteoglycans as extracellular docking molecules for matrilysin (matrix metalloproteinase 7). J Biol Chem 275:4183-91
Yu, W H; Yu, S; Meng, Q et al. (2000) TIMP-3 binds to sulfated glycosaminoglycans of the extracellular matrix. J Biol Chem 275:31226-32
Nagase, H; Woessner Jr, J F (1999) Matrix metalloproteinases. J Biol Chem 274:21491-4
Woessner Jr, J F (1999) Matrix metalloproteinase inhibition. From the Jurassic to the third millennium. Ann N Y Acad Sci 878:388-403
Woessner Jr, J F (1998) Role of matrix proteases in processing enamel proteins. Connect Tissue Res 39:69-73;discussion 141-9
Baragi, V M; Qiu, L; Gunja-Smith, Z et al. (1997) Role of metalloproteinases in the development and healing of acetic acid-induced gastric ulcer in rats. Scand J Gastroenterol 32:419-26
Gunja-Smith, Z; Morales, A R; Romanelli, R et al. (1996) Remodeling of human myocardial collagen in idiopathic dilated cardiomyopathy. Role of metalloproteinases and pyridinoline cross-links. Am J Pathol 148:1639-48
Woessner Jr, J F (1996) Regulation of matrilysin in the rat uterus. Biochem Cell Biol 74:777-84

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