ИСТИНА

Background: CLEC2 is a recently discovered platelet receptor for podoplanin, a cell surface ligand known to be exposed on tumor cells. Podoplanin-CLEC2 interaction is also important during ontogenesis. It is possible that podoplanin-induced platelet activation has its share in tumor-associated thrombophilia; CLEC2-mediated platelet activation leading to trombocytopenia, consumptive coagulopathy and purpura are associated with Kasabach-Merritt Phenomenon. Aims: Development of a comprehensive computational systems biology model of CLEC2-mediated platelet activation to investigate its regulation mechanisms and identify possible pharmacological targets. Methods: The model describes behavior of CLEC2, phosphorylated CLEC2 and its complex with Syk kinase in platelet membrane and lipid raft. Reactions involving Src, Btk and PI3K kinases are also included. The final activation event incorporated in the model is PLC-gamma-mediated rise in cytosolic calcium. The final set of ODE was integrated by LSODA method in COPASI software (COPASI.org). Results: The constructed model described well experimental data of platelets activation and cytosolic calcium rise in platelet suspensions from (Jillian L. Astarita et al Frontiers in Immunology vol 3 Article 238). Interestingly, the model predicted that CLEC2-dependent signaling pathway can induce intracellular calcium oscillations in individual platelets. The experimentally observed lag times of CLEC2-mediated platelet activation could be explained by the time required for the receptor-ligand complex diffusion into the lipid raft. Addition of a PI3K inhibitor in the model abolished platelet CLEC2-medited activation completely, while a Btk kinase inhibitor ibrutinib was predicted to decrease the amplitude of platelet activation two-fold. Conclusions: A first comprehensive multicompartmental model of platelet CLEC2 signaling is developed and validated leading to generation of several predictions for basic research and pharmacology.