Open Access
CC BY 4.0 · TH Open 2024; 08(02): e232-e242
DOI: 10.1055/s-0044-1786987
Original Article

Platelet Activation Pathways Controlling Reversible Integrin αIIbβ3 Activation

Jinmi Zou
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
2   Department of Biochemistry and Internal Medicine, Maastricht University Medical Center + , Maastricht, The Netherlands
,
Siyu Sun
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
2   Department of Biochemistry and Internal Medicine, Maastricht University Medical Center + , Maastricht, The Netherlands
,
Ilaria De Simone
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
,
2   Department of Biochemistry and Internal Medicine, Maastricht University Medical Center + , Maastricht, The Netherlands
,
Philip G. de Groot
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
,
Bas de Laat
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
,
Mark Roest
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
,
Johan W.M. Heemskerk
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
,
1   Platelet (patho)physiology, Synapse Research Institute, Maastricht, The Netherlands
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Abstract

Background Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under specific conditions, allowing a second phase of platelet aggregation. The signaling pathways that differentiate between a permanent or transient activation state of platelets are poorly elucidated.

Objective To explore platelet signaling mechanisms induced by the collagen receptor glycoprotein VI (GPVI) or by protease-activated receptors (PAR) for thrombin that regulate time-dependent αIIbβ3 activation.

Methods Platelets were activated with collagen-related peptide (CRP, stimulating GPVI), thrombin receptor-activating peptides, or thrombin (stimulating PAR1 and/or 4). Integrin αIIbβ3 activation and P-selectin expression was assessed by two-color flow cytometry. Signaling pathway inhibitors were applied before or after agonist addition. Reversibility of platelet spreading was studied by microscopy.

Results Platelet pretreatment with pharmacological inhibitors decreased GPVI- and PAR-induced integrin αIIbβ3 activation and P-selectin expression in the target order of protein kinase C (PKC) > glycogen synthase kinase 3 > β-arrestin > phosphatidylinositol-3-kinase. Posttreatment revealed secondary αIIbβ3 inactivation (not P-selectin expression), in the same order, but this reversibility was confined to CRP and PAR1 agonist. Combined inhibition of conventional and novel PKC isoforms was most effective for integrin closure. Pre- and posttreatment with ticagrelor, blocking the P2Y12 adenosine diphosphate (ADP) receptor, enhanced αIIbβ3 inactivation. Spreading assays showed that PKC or P2Y12 inhibition provoked a partial conversion from filopodia to a more discoid platelet shape.

Conclusion PKC and autocrine ADP signaling contribute to persistent integrin αIIbβ3 activation in the order of PAR1/GPVI > PAR4 stimulation and hence to stabilized platelet aggregation. These findings are relevant for optimization of effective antiplatelet treatment.

Authors' Contributions

J.Z. performed experiments, analyzed results, and drafted the manuscript; S.S. and I.D.S. edited the manuscript; P.G.d.G., B.d.L., H.t.C., and M.R. provided supervision and edited the manuscript; J.W.M.H. and F.S. supervised research and wrote the manuscript. All authors approved the final version of the manuscript.


Supplementary Material



Publikationsverlauf

Eingereicht: 04. Januar 2024

Angenommen: 12. April 2024

Artikel online veröffentlicht:
22. Juni 2024

© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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