CLEC-2-dependent activation of mouse platelets is weakly inhibited by cAMP but not by cGMP
| Autor: | Alessandra, Borgognone, Leyre Navarro Nunez, Joao Natalino Correia, Pollitt, Alice Y., Thomas Steven, G., Eble, Johannes A., Pulcinelli, FABIO MARIA, Melanie, Madhani, Watson, Steve P. |
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| Rok vydání: | 2013 |
| Předmět: |
Blood Platelets
C‐type lectin Platelet Aggregation camp Viper Venoms platelet activation platelets lymphangiogenesis cyclic nucleotides c-type lectin clec-2 blood platelets Nitric Oxide Mice Platelet Adhesiveness Cell Adhesion Cyclic AMP Animals Lectins C-Type Cyclic GMP Membrane Glycoproteins Original Articles Platelet Activation Epoprostenol PLATELETS Mice Inbred C57BL Calcium Original Article |
| Zdroj: | Journal of Thrombosis and Haemostasis |
| ISSN: | 1538-7836 |
| Popis: | Summary Background The activation of platelet CLEC‐2 by podoplanin on lymphatic endothelial cells (LECs) has a critical role in prevention of mixing of lymphatic and blood vasculatures during embryonic development. Paradoxically, LECs release cAMP and cGMP‐elevating agents, prostacyclin (PGI2) and nitric oxide (NO), respectively, which are powerful inhibitors of platelet activation. This raises the question of how podoplanin is able to activate CLEC‐2 in the presence of the inhibitory cyclic nucleotides. Objectives We investigated the influence of cyclic nucleotides on CLEC‐2 signaling in platelets. Methods We used rhodocytin, CLEC‐2 monoclonal antibody, LECs and recombinant podoplanin as CLEC‐2 agonists on mouse platelets. The effects of the cyclic nucleotide‐elevating agents PGI2, forskolin and the NO‐donor GSNO were assessed with light transmission aggregometry, flow cytometry, protein phosphorylation and fluorescent imaging of platelets on LECs. Results We show that platelet aggregation induced by CLEC‐2 agonists is resistant to GSNO but inhibited by PGI2. The effect of PGI2 is mediated through decreased phosphorylation of CLEC‐2, Syk and PLCγ2. In contrast, adhesion and spreading of platelets on recombinant podoplanin, CLEC‐2 antibody and LECs is not affected by PGI2 and GSNO. Consistent with this, CLEC‐2 activation of Rac, which is required for platelet spreading, is not altered in the presence of PGI2. Conclusions The present results demonstrate that platelet adhesion and activation on CLEC‐2 ligands or LECs is maintained in the presence of PGI2 and NO. |
| Databáze: | OpenAIRE |
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