Platelet CLEC-2 Ligation Offers Critical Enhancement for ADP and Thrombin-induced Activation via Synergy between Intracellular Signalling Pathways of CLEC-2 and G-protein Coupled Receptorsтезисы доклада

Дата последнего поиска статьи во внешних источниках: 21 мая 2019 г.

Работа с тезисами доклада

[1] Martyanov A., Panteleev M., Sveshnikova A. Platelet clec-2 ligation offers critical enhancement for adp and thrombin-induced activation via synergy between intracellular signalling pathways of clec-2 and g-protein coupled receptors // Res Pract Thromb Haemost. — Suppl. 1. — [New York, N.Y.], United States: [New York, N.Y.], United States, 2018. — P. 46–46. Background: CLEC-2 is a platelet receptor with a proposed role in maintaining blood vessel integrity promoting leukocyte extravasation from microvessels during inflammation. However, standalone CLEC-2 induced platelet activation has a significant lag phase and altogether weak platelet responses. Thus why CLEC-2 ligation could be of significance in some conditions remains elusive. Aims: To analyze the origin of the weak responses of platelets to CLEC-2 stimulation as well as a model setting in which these responses could be critical. Methods: We constructed a comprehensive 3-dimensional reaction-diffusion computational model, which describes CLEC-2, P2Y1, P2Y12, PAR1, PAR4 ligation, receptor diffusion in the membrane and receptor-induced signalosome assembly. Activation of calcium-fluorophore loaded platelets by fucoidan, ADP and thrombin was studied by aggregometry, flow cytometry and TIRF microscopy. Results: Based on modelling results it can be claimed that both Syk and SFK kinases phosphorylate CLEC-2 cytoplasmic domain. CLEC-2 induced cytosolic Ca2+ spiking was predicted by model and confirmed by TIRF microscopy. Flow cytometry assay, as well as TIRF microscopy, in line with the model prediction, proved signalling interplay between CLEC-2 and ADP/thrombin (Gq and Gi) signalling pathways: platelet cytosolic calcium responses to low doses of ADP or thrombin dramatically increase in the presence of CLEC-2 agonist. Surprisingly there are two merging points of the signalling cascades, those are PI3K and PLC activity. Conclusions: Slow CLEC-2 induced platelet activation occurs due to the need of signalosome assembly. In presence of ADP or low concentrations of thrombin it can be significantly enhanced via synergetic PI3K and PLC activation by Gq, Gi and tyrosine-kinase signalling pathways. This synergy makes CLEC-2 role critical for vessel wall protection in inflammation.

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