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Platelet surface glutathione reductase-like activity.
David W Essex1, Mengru Li, Richard D Feinman
1University of Texas Health Science Center at San Antonio, Mail Code 7880, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA. essex@uthscsa.edu
Blood
|May 15, 2004
Summary
Glutathione disulfide (GSSG) enhances platelet aggregation by converting to reduced glutathione (GSH) on the platelet surface. This process activates platelets and facilitates agonist-induced activation via the alpha(IIb)beta(3) receptor.
Area of Science:
- Biochemistry
- Hematology
- Cell Biology
Background:
- Reduced glutathione (GSH) and glutathione disulfide (GSSG) are known to influence platelet function.
- Previous studies indicated that GSH or a GSH/GSSG mixture potentiates platelet aggregation.
Purpose of the Study:
- To investigate the effect of GSSG alone on platelet aggregation.
- To elucidate the mechanism by which GSSG influences platelet activation.
Main Methods:
- Platelet aggregation assays were performed.
- GSSG conversion to GSH on the platelet surface was measured.
- Changes in sulfhydryl groups of the alpha(IIb)beta(3) receptor were analyzed.
Main Results:
- GSSG alone was found to potentiate platelet aggregation.
- Platelet surface flavoprotein-dependent mechanisms efficiently converted GSSG to GSH.
- GSSG addition led to sulfhydryl generation in the alpha(IIb)beta(3) receptor's beta subunit.
Conclusions:
- GSSG potentiates platelet aggregation through its conversion to GSH via a platelet surface mechanism.
- The generated GSH establishes a redox potential conducive to platelet activation.
- GSSG facilitates agonist-induced platelet activation by modifying the alpha(IIb)beta(3) fibrinogen receptor.