Naslov
Phosphatidylserine surface expression and integrin alpha IIb beta 3 activity on thrombin/convulxin stimulated platelets/particles of different sizes

Autori
Rukoyatkina, Natalia ; Jurak Begonja, Antonija ; Geiger, Joerg ; Eigenthaler, Martin ; Walter, Ulrich ; Gambaryan, Stepan

Izvornik
British journal of haematology (0007-1048) 144 (2009), 4; 591-602

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
phosphatidylserine; platelets; apoptosis; microparticles

Sažetak
Platelets stimulated by a combination of thrombin/convulxin have been shown to develop two to three populations characterized by different phosphatidylserine (PS) surface expression and integrin alpha IIb beta 3 activity. To determine how these markers are distributed on the surface of platelets/particles, we studied Annexin V and PAC-1 binding to platelets/particles of different sizes by flow cytometry analysis and evaluated influences of calpain and caspase inhibitors on thrombin/convulxin-activated platelets. Analysed platelets/particles were divided by their sizes, according to the standard size beads, into seven populations from 0.37 to 4.8 microm. PAC-1 binding/microm(2) was almost equal in platelets/particles ranging from 1.2 to 4.8 microm and was significantly lower on smaller-sized particles sizes (0.37-0.7 microm). PS surface exposure/microm(2) was high in the particles of 0.37-1.2 microm and very low in platelets (2.6-4.8 microm). Upon thrombin/convulxin stimulation caspase inhibitors prevented microparticle (MP) formation, while a calpain inhibitor stimulated MP formation. It was also shown that stimulated platelets are heterogeneous not only in their ability to activate alpha IIb beta 3 integrin complex and expose PS on their surface, but also in the distribution of activation markers, which strongly depends on platelet/particle size and that platelets/particles of different sizes provide different responses to the same stimulus.

Izvorni jezik
Engleski

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