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Expression and tissue localization of membrane-types 1, 2, and 3 matrix metalloproteinases in rheumatoid synovium
H Yamanaka1, K Makino, M Takizawa
1Department of Pathology, School of Medicine, Keio University, Tokyo, Japan.
Abstract:
In vitro, membrane-type matrix metalloproteinases (MT-MMP) are known to activate the zymogen of MMP-2 (proMMP-2, progelatinase A), which is one of the key MMP in joint destruction in rheumatoid arthritis. In the present study, we examined the production and activation of proMMP-2, and the expression of MT1-MMP, MT2-MMP, and MT3-MMP, their correlation with proMMP-2 activation, and their localization in rheumatoid synovial tissue. Using sandwich enzyme immunoassay and gelatin zymography techniques, proMMP-2 production levels and activation ratios were found to be significantly higher in rheumatoid synovium compared with normal synovium (p < 0.01). Quantitative RT-PCR analyses demonstrated that MT1-MMP and MT3-MMP were expressed in all rheumatoid synovial tissue (30 of 30 cases), but that the mean expression level of MT1-MMP was approximately 11-fold higher than MT3-MMP. Significant correlation was found between the mRNA expression level of MT1-MMP and the activation ratio of proMMP-2 (p < 0.01). In situ hybridization indicated that the hyperplastic lining cells of rheumatoid synovium expressed MT1-MMP. Immunohistochemistry demonstrated that MT1-MMP was co-localized with MMP-2 and with a tissue inhibitor of metalloproteinase-2, and was mainly located in the rheumatoid synovial lining cells. In situ zymography of rheumatoid synovium showed gelatinolytic activity, predominantly in the lining cell layer. This activity was blocked when incubated with BB94, a specific MMP inhibitor. These results demonstrate that MT1-MMP plays an important role in the activation of proMMP-2 in the rheumatoid synovial lining cell layer, and suggest that its activity may be involved in the cartilage destruction of rheumatoid arthritis.
Insights
Membrane-type 1 matrix metalloproteinase (MT1-MMP) activates proMMP-2 in rheumatoid arthritis synovium. This MT1-MMP activity in synovial lining cells is linked to joint destruction and cartilage damage in rheumatoid arthritis.
Area of Science:
- Rheumatology
- Molecular Biology
- Biochemistry
Background:
- Matrix metalloproteinases (MMPs) are implicated in joint destruction in rheumatoid arthritis.
- Membrane-type matrix metalloproteinases (MT-MMPs) activate proMMP-2, a key MMP in rheumatoid arthritis pathogenesis.
- The specific roles and localization of MT-MMPs in rheumatoid synovium require further investigation.
Purpose of the Study:
- To investigate the production, activation, and expression of proMMP-2 and MT-MMPs in rheumatoid synovial tissue.
- To correlate MT-MMP expression with proMMP-2 activation and localization within the synovium.
- To elucidate the role of MT1-MMP in proMMP-2 activation and potential involvement in rheumatoid arthritis-related cartilage destruction.
Main Methods:
- Sandwich enzyme immunoassay and gelatin zymography to quantify proMMP-2 production and activation.
- Quantitative RT-PCR to analyze MT1-MMP, MT2-MMP, and MT3-MMP mRNA expression.
- In situ hybridization and immunohistochemistry to determine MT-MMP localization.
- In situ zymography to assess gelatinolytic activity in rheumatoid synovium.
Main Results:
- ProMMP-2 production and activation ratios were significantly higher in rheumatoid synovium compared to normal synovium.
- MT1-MMP and MT3-MMP were expressed in all rheumatoid synovial tissues, with MT1-MMP expression being approximately 11-fold higher than MT3-MMP.
- Significant correlation found between MT1-MMP mRNA expression and proMMP-2 activation ratio (p < 0.01).
- MT1-MMP was localized in rheumatoid synovial lining cells, co-localized with MMP-2 and TIMP-2, and associated with gelatinolytic activity.
Conclusions:
- MT1-MMP plays a crucial role in proMMP-2 activation within the rheumatoid synovial lining cell layer.
- MT1-MMP activity in this location suggests its involvement in the cartilage destruction observed in rheumatoid arthritis.
- Targeting MT1-MMP may offer a therapeutic strategy for rheumatoid arthritis.