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Updated: May 21, 2026
Detection of Functional Matrix Metalloproteinases by Zymography
Published on: November 8, 2010
On the origin of matrix metalloproteinase-2 and -9 in blood platelets
Aneta Wrzyszcz1, Mieczyslaw Wozniak
1Department of Medical Laboratory Diagnostics, Wroclaw Medical University, Wroclaw, Poland. aneta.wrzyszcz@am.wroc.pl
Abstract:
To date, several matrix metalloproteinases (MMPs) have been identified in human platelets. In most research studies, the platelets are obtained using the isolation method from plasma by centrifugation and washing. The metalloproteinase content in the platelets can be affected by the isolation technique and the leukocyte contamination. In this work, we studied the influence of the isolation method on the detection of platelet MMPs and explore the expression of these enzymes in megakaryoblastic MEG-01 cells. We investigated the expression of mRNAs encoding for MMP-2 and -9 in platelets and MEG-01 cells. Using gelatin zymography and western blotting, we examined the expression and release of MMP-2 and 9 by platelets and MEG-01 cells and checked whether the amount of the released MMPs depends on the volume of tested platelet and leukocyte contamination. To investigate the MMP-2 expression profile, we used zymography and flow cytometry. Platelets, in contrast to the MEG-01 cells, neither contain mRNA for MMP-2 nor -9. The platelets contain pro-MMP-2 and release it during the activation. The population of uncontaminated (leukocytes<0.02%) platelets contained no MMP-9 or the active form of MMP-2. We have observed that the activity of MMP-2 in platelet lysate is proportional to their mean volume and that the MMP-2 activity may not be detected if very small platelets are examined. We conclude that the detection of gelatinases in platelets depends on platelet isolation techniques and the degree of leukocyte contamination.
Insights
Platelet matrix metalloproteinases (MMPs) detection depends on isolation methods and leukocyte contamination. Uncontaminated platelets lack MMP-9 and active MMP-2, with MMP-2 levels varying with platelet size.
Area of Science:
- Biochemistry
- Hematology
- Cell Biology
Background:
- Human platelets contain several matrix metalloproteinases (MMPs).
- Platelet MMP content can be influenced by isolation techniques and leukocyte contamination.
- Previous research has identified MMPs in platelets, but their expression and detection are sensitive to methodology.
Purpose of the Study:
- To investigate the influence of isolation methods on the detection of platelet MMPs.
- To explore the expression of MMP-2 and MMP-9 in platelets and MEG-01 cells.
- To determine the impact of leukocyte contamination and platelet volume on MMP detection.
Main Methods:
- mRNA expression analysis for MMP-2 and MMP-9 in platelets and MEG-01 cells.
- Gelatin zymography and western blotting to assess MMP-2 and MMP-9 expression and release.
- Flow cytometry for MMP-2 expression profiling.
- Analysis of platelet and leukocyte contamination levels.
Main Results:
- Platelets, unlike MEG-01 cells, do not contain mRNA for MMP-2 or MMP-9.
- Platelets contain pro-MMP-2 and release it upon activation.
- Uncontaminated platelets (<0.02% leukocytes) showed no MMP-9 or active MMP-2.
- MMP-2 activity in platelet lysates correlated with mean platelet volume; smaller platelets may yield undetectable levels.
Conclusions:
- The detection of gelatinases (MMP-2, MMP-9) in platelets is critically dependent on the isolation technique employed.
- Leukocyte contamination significantly affects the apparent presence and activity of MMPs in platelet preparations.
- Platelet size is a factor influencing the detectability of MMP-2 activity.
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