Related Experiment Videos
Synovial procollagenase activation by human mast cell tryptase dependence upon matrix metalloproteinase 3 activation
B L Gruber1, M J Marchese, K Suzuki
1Division of Allergy, Rheumatology and Clinical Immunology, Veterans Administration, Northport, New York 11768.
Abstract:
Mast cells have been implicated in the pathogenesis of the matrix degradation observed in the cartilaginous and osseous structures of the rheumatoid joint. We previously reported that human mast cell tryptase, a 134-kD granule-associated neutral protease, is present in rheumatoid synovium and can activate collagenase in crude culture medium in vitro. the present study attempts to depict the precise mechanism of this activation. To express full activation of latent collagenase, matrix metalloproteinase 3 (MMP-3) or stromelysin, can be activated by tryptase in a time and dose-dependent manner. Tryptase was not capable of generating active collagenase in the crude media from cultured rheumatoid synoviocytes depleted of proMMP-3 by immunoadsorption. In addition, the function of the tissue inhibitor of metalloproteinases (TIMP) was not altered by tryptase, and SDS-PAGE analysis revealed no degradation of TIMP by tryptase. The tryptase dependent activation of synoviocyte procollagenase thereby appears to be entirely dependent upon its ability to activate proMMP-3.
Insights
Human mast cell tryptase activates collagenase in rheumatoid joints by activating matrix metalloproteinase 3 (MMP-3). This process is crucial for matrix degradation in rheumatoid arthritis, independent of tissue inhibitor of metalloproteinases (TIMP).
Area of Science:
- Rheumatology
- Cell Biology
- Biochemistry
Background:
- Mast cells and their enzyme, human mast cell tryptase, are implicated in rheumatoid joint matrix degradation.
- Previous research showed tryptase can activate collagenase in vitro.
Purpose of the Study:
- To elucidate the precise mechanism by which human mast cell tryptase activates collagenase.
- To investigate the role of matrix metalloproteinase 3 (MMP-3) in this activation pathway.
Main Methods:
- Culturing rheumatoid synoviocytes.
- Using immunoadsorption to deplete proMMP-3.
- Enzyme activation assays.
- SDS-PAGE analysis to assess protein degradation and function.
Main Results:
- Tryptase activates latent collagenase through matrix metalloproteinase 3 (MMP-3) in a time- and dose-dependent manner.
- Tryptase could not activate collagenase in synoviocytes depleted of proMMP-3.
- Tryptase did not alter the function or degrade the tissue inhibitor of metalloproteinases (TIMP).
Conclusions:
- The activation of rheumatoid synoviocyte procollagenase by tryptase is solely dependent on its ability to activate proMMP-3.
- This mechanism highlights a key pathway in the pathogenesis of rheumatoid arthritis matrix degradation.