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Platelet Adhesion and Aggregation Under Flow using Microfluidic Flow Cells
Published on: October 27, 2009
Glycoprotein Ib alpha peptides inhibit thrombin and SFLLRN-induced platelet aggregation
L P McKeown1, S B Williams, K E Hansmann
1Clinical Center, National Institutes of Health, Bethesda, Maryland 20892, USA.
The Journal of Laboratory and Clinical Medicine
|November 1, 1996
Summary
Synthetic peptides derived from platelet glycoprotein Ib-alpha (GPIb(alpha)) inhibit thrombin-induced platelet aggregation. This suggests a novel mechanism for modulating platelet activation and aggregation using specific GPIb(alpha) peptide sequences.
Area of Science:
- Biochemistry
- Hematology
- Molecular Biology
Background:
- Platelet activation and aggregation are crucial for hemostasis.
- The platelet glycoprotein Ib-alpha (GPIb(alpha)) receptor binds thrombin, enhancing platelet activation via 7-transmembrane domain receptors (7-TMDRs).
Purpose of the Study:
- To investigate the role of specific GPIb(alpha) peptide sequences in modulating platelet aggregation.
- To identify functional regions within GPIb(alpha) responsible for thrombin-mediated platelet activation.
Main Methods:
- Synthesis of 24 peptides from the GPIb(alpha) amino acid sequence F216-T240.
- Assessment of peptide effects on platelet aggregation induced by thrombin and the 7-TMDR peptide SFLLRN.
- Testing specificity of peptide inhibition against various agonists (collagen, ristocetin, calcium ionophore, botrocetin).
Main Results:
- Several peptides from the W219-V227 sequence of GPIb(alpha) inhibited platelet aggregation.
- Inhibitory activity was dependent on the amino acid sequence A224-N226 (AEN).
- These GPIb(alpha) peptides specifically inhibited thrombin- or SFLLRN-induced aggregation but not aggregation induced by other agonists.
Conclusions:
- A specific region within GPIb(alpha) modulates platelet aggregation induced by alpha-thrombin.
- These findings suggest a novel mechanism for modulating platelet activation and aggregation using synthetic and natural peptides.
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