Osteoarthritis (OA) is a common disabling joint disease that principally afflicts the elderly. A progressive destruction of the articular surface results from increased proteolytic activity within the cartilage. The applicant's laboratory has provided evidence of a novel proteinase, MMP proenzyme activator (MMP-PA), which activates MMP-3 (stromelysin) and MMP-9 (92k gelatinase). MMP-PA is produced by articular cartilage and may serve as an important regulator of MMP activity in this tissue in processes of development, growth and repair. The applicant's studies have also led to the discovery of serine proteinase(s) produced by cartilage that inactivate the tissue inhibitors of metalloproteinases (TIMPs). Thus, these two components, that are synthesized by cartilage, constitute an endogenous system that is likely to be a critical determinant of tissue proteolysis. The test hypothesis is that overexpression of these proteinases in OA disrupts the tight regulation of a cascade of extracellular matrix degrading enzymes, ultimately causing cartilage destruction. The goals of this proposal are the purification of MMP-PA and TIMP-cleaving proteinases, and isolation of cDNA clones. MMP-PA activates not only MMP-3 and MMP-9, but perhaps an entire degradative cascade in cartilage. Experiments are therefore proposed to determine whether MMP-PA stimulates aggrecanase-like activity in cartilage. TIMP catabolites in OA cartilage will be examined for terminal amino acid sequences consistent with in vivo action of TIMP-cleaving enzyme(s). It is suggested that by specifically inhibiting these enzymes in the cartilage of OA patients, a net gain in extracellular matrix will be created. It is further speculated that the study of serine proteinases produced by OA cartilage may have strong implications for the management of this debilitating disease.

Agency
National Institute of Health (NIH)
Institute
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Type
Research Project (R01)
Project #
2R01AR016265-22A2
Application #
2465268
Study Section
Orthopedics and Musculoskeletal Study Section (ORTH)
Project Start
1977-04-01
Project End
2001-12-31
Budget Start
1998-01-01
Budget End
1998-12-31
Support Year
22
Fiscal Year
1998
Total Cost
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
City
Boston
State
MA
Country
United States
Zip Code
02199
Sullivan, Lawrence G; Hasan, Tayyaba; Wright, Marianne et al. (2002) Photodynamic treatment has chondroprotective effects on articular cartilage. J Orthop Res 20:241-8
Toriyama, M; Rosenberg, A E; Mankin, H J et al. (1998) Matrix metalloproteinase digestion of aggrecan in human cartilage tumours. Eur J Cancer 34:1969-73
Towle, C A; Wright, M; Hecht, A C et al. (1998) A matrix metalloproteinase proenzyme activator produced by articular cartilage. Biochem Biophys Res Commun 247:324-31
Brill, S; Li, S; Lyman, C W et al. (1996) The Ras GTPase-activating-protein-related human protein IQGAP2 harbors a potential actin binding domain and interacts with calmodulin and Rho family GTPases. Mol Cell Biol 16:4869-78
Weissbach, L; Settleman, J; Kalady, M F et al. (1994) Identification of a human rasGAP-related protein containing calmodulin-binding motifs. J Biol Chem 269:20517-21
Towle, C A; Weissbach, L; Treadwell, B V (1992) Alternatively spliced annexin XI transcripts encode proteins that differ near the amino-terminus. Biochim Biophys Acta 1131:223-6
Towle, C A; Treadwell, B V (1992) Identification of a novel mammalian annexin. cDNA cloning, sequence analysis, and ubiquitous expression of the annexin XI gene. J Biol Chem 267:5416-23