| Autor: |
Heinzmann, A.C.A., Karel, M.F.A., Coenen, D.M., Vajen, T., Meulendijks, N.M.M., Nagy, M., Suylen, D.P.L., Cosemans, J.M.E.M., Heemskerk, J.W.M., Hackeng, T.M., Koenen, R.R. |
| Jazyk: |
angličtina |
| Rok vydání: |
2020 |
| Předmět: |
|
| Zdroj: |
Atherosclerosis, October, 310, 17-25 |
| Popis: |
Background and aims:Platelets can release extracellular vesicles (EVs) upon stimulation with various agonists.Interestingly, platelets from patients with Glanzmann thrombasthenia have reduced EV release. These plateletslack functional αIIbβ3integrins, indicating that αIIbβ3integrin is critical in vesicle release. Integrin activation iscentral in platelet function and is associated with e.g. adhesion, aggregation and cytoskeletal rearrangement.However, while platelet activation pathways are widely known, the mechanisms underlying EV release remainuncharacterized. We investigated the role of integrin αIIbβ3, phosphatidyl serine (PS) exposure, cytoskeletalrearrangement and their associated signalling pathways in EV release.Methods:EVs were isolated from activated platelets. Platelet activation status was measured by multicolour flowcytometry. A panel of pharmacologic inhibitors was used to interfere in specific signalling pathways. EV releasewas quantified enzymatically based on membrane PS content and nanoparticle tracking analysis. In addition,real-time visualization of EV shedding with confocal microscopy and EVs with Cryo-TEM imaging was per-formed.Results:Platelet activation with convulxin resulted in higher EV release than with activation by thrombin.Kinetic measurements indicated that EV release followed the pattern of αIIbβ3integrin activation and subsequentclosure paralleled by PS exposure. Prevention of αIIbβ3activation with the inhibitor tirofiban dramaticallysuppressed EV release. Similar results were obtained using αIIbβ3-deficient platelets from patients withGlanzmann thrombasthenia. Inhibition of actin cytoskeleton rearrangement decreased EV release, whereas in-hibition of individual signalling targets upstream of cytoskeletal rearrangement showed no such effects.Conclusion:Platelet EV release requires three main events: integrin activation and closure, PS exposure, andcytoskeletal rearrangement. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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