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Activation of human matrix metalloproteinases by various bacterial proteinases
1Department of Microbiology, Kumamoto University School of Medicine, Kumamoto 860, Japan.
Abstract:
Matrix metalloproteinases (MMPs) are zinc-containing proteinases that participate in tissue remodeling under physiological and pathological conditions. To test the involvement of bacterial proteinases in tissue injury during bacterial infections, we investigated the activation potential of various bacterial proteinases against precursors of MMPs (proMMPs) purified from human neutrophils (proMMP-8 and -9) and from human fibrosarcoma cells (proMMP-1). Each proMMP was subjected to treatment with a series of bacterial proteinases at molar ratios of 0.01-0.1 (bacterial proteinase to proMMP), and activities of MMPs generated were determined. Among six different bacterial proteinases, thermolysin family enzymes (family M4) such as Pseudomonas aeruginosa elastase, Vibrio cholerae proteinase, and thermolysin strongly activated all three proMMPs via limited proteolysis to generate active forms of the MMPs. N-terminal sequence analysis of the active MMPs revealed that cleavage occurred at the Val82-Leu83 and Thr90-Phe91 bonds of proMMP-1 and proMMP-9, respectively, which are located near the N terminus of the catalytic domain of MMPs. In contrast, Serratia 56-kDa proteinase and Pseudomonas alkaline proteinase, both of which are classified as members of the serralysin subfamily of zinc metalloproteinases (family M10), and Serratia 73-kDa thiol proteinase did not evidence proteolytic processing or activation of proMMP-1, -8, and -9 under these experimental conditions. These results indicate that bacterial proteinases may play an important role in tissue destruction and disintegration of extracellular matrix at the site of infections.
Insights
Certain bacterial proteinases, particularly thermolysin-family enzymes, activate matrix metalloproteinases (MMPs) precursors. This activation contributes to tissue damage during bacterial infections by enabling extracellular matrix degradation.
Area of Science:
- Biochemistry
- Microbiology
- Molecular Biology
Background:
- Matrix metalloproteinases (MMPs) are crucial for tissue remodeling in health and disease.
- Bacterial infections can cause tissue injury, but the role of bacterial proteinases in this process is not fully understood.
Purpose of the Study:
- To investigate the potential of bacterial proteinases to activate human matrix metalloproteinase precursors (proMMPs).
- To determine if bacterial proteinases contribute to tissue destruction during infections.
Main Methods:
- Purified proMMPs (proMMP-1, -8, and -9) were treated with various bacterial proteinases.
- Activation of proMMPs was assessed by measuring generated MMP activity.
- N-terminal sequencing identified cleavage sites on activated MMPs.
Main Results:
- Thermolysin-family bacterial proteinases (e.g., Pseudomonas aeruginosa elastase, Vibrio cholerae proteinase, thermolysin) effectively activated all tested proMMPs.
- Activation involved limited proteolysis at specific sites near the catalytic domain's N-terminus.
- Serralysin subfamily proteinases and a thiol proteinase did not activate proMMPs under the experimental conditions.
Conclusions:
- Bacterial proteinases, especially from the thermolysin family, can activate human MMPs.
- This activation mechanism likely contributes to tissue destruction and extracellular matrix degradation at infection sites.