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Platelet shape change induced by the peptide YFLLRNP
K Otterdal1, T M Pedersen, N O Solum
1Research Institute for Internal Medicine, Rikshospitalet, University of Oslo, Sognsvannsveien 20, 0027 Oslo, Norway. kari.otterdal@klinmed.uio.no
Thrombosis Research
|September 13, 2001
Summary
Platelet shape change can be induced by YFLLRNP independently of calcium. This distinct process involves cytoskeletal reorganization but not full activation, aggregation, or clot retraction.
Area of Science:
- Hematology
- Cell Biology
- Biochemistry
Background:
- Platelet activation is a complex process initiated by various stimuli.
- Platelet shape change is an early, distinct response to activation.
- Calcium ions play a crucial role in many platelet activation pathways.
Purpose of the Study:
- To investigate the YFLLRNP-induced platelet shape change.
- To determine if this shape change is dependent on cytosolic Ca2+ concentration.
- To characterize the molecular events associated with YFLLRNP-induced shape change.
Main Methods:
- Human citrated platelet-rich plasma (PRP) was used.
- Platelets were activated with 300 microM YFLLRNP.
- Scanning electron microscopy (SEM) was employed.
- Protein analysis via electrophoresis and FITC-annexin V binding assays were performed.
Main Results:
- YFLLRNP induced significant platelet shape change with pseudopod extension.
- Cytoskeletal reorganization was evident, indicated by increased sedimenting protein content.
- No activation of the GP IIb-IIIa complex, clot retraction, or phospholipid asymmetry disturbance was observed.
- Platelet aggregation and dense granule secretion were not induced at 300 microM YFLLRNP.
Conclusions:
- YFLLRNP-induced shape change is a distinct, calcium-independent process.
- This process involves cytoskeletal remodeling but represents a partial activation state.
- The pathophysiological significance of such partly activated platelets in circulation warrants further investigation.