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Procoagulant activity and active calpain in platelet-derived microparticles
J M Pasquet1, F Toti, A T Nurden
1UMR 5533 CNRS, Hôpital Cardiologique du Haut-Lévèque, Pessac, France.
Thrombosis Research
|June 15, 1996
Summary
Platelet microparticles, formed by calcium changes, show procoagulant activity. These microparticles exclusively contain activated calpain, suggesting a role in platelet function and hemostasis.
Area of Science:
- Hematology
- Cell Biology
- Biochemistry
Background:
- Microparticles are released from activated platelets and implicated in various pathologies.
- Understanding microparticle formation and function is crucial for hemostasis research.
Purpose of the Study:
- To investigate microparticle formation induced by intracellular calcium increase via Ca(2+)-ATPase inhibition.
- To characterize the procoagulant activity and molecular content of these microparticles.
Main Methods:
- Platelet activation and microparticle isolation using sucrose gradient centrifugation.
- Flow cytometry with annexin V for procoagulant activity assessment.
- Western blotting to detect active calpain.
Main Results:
- Microparticle formation was triggered by elevated intracellular calcium.
- Microparticles exhibited significant procoagulant activity, inhibited by annexin V.
- Activated calpain was exclusively found within microparticles, not on their surface.
Conclusions:
- The study confirms the procoagulant nature of platelet microparticles.
- Activated calpain's presence suggests its involvement in microparticle-associated functions.