Modified diadenosine tetraphosphates with dual specificity for P2Y1 and P2Y12 are potent antagonists of ADP-induced platelet activation
Article first published online: 12 DEC 2012
© 2012 International Society on Thrombosis and Haemostasis
Journal of Thrombosis and Haemostasis
Volume 10, Issue 12, pages 2573–2580, December 2012
How to Cite
CHANG, H., YANACHKOV, I. B., DIX, E. J., LI, Y. F., BARNARD, M. R., WRIGHT, G. E., MICHELSON, A. D. and FRELINGER, A. L. (2012), Modified diadenosine tetraphosphates with dual specificity for P2Y1 and P2Y12 are potent antagonists of ADP-induced platelet activation. Journal of Thrombosis and Haemostasis, 10: 2573–2580. doi: 10.1111/jth.12035
- Issue published online: 12 DEC 2012
- Article first published online: 12 DEC 2012
- Accepted manuscript online: 20 OCT 2012 11:33AM EST
- Received 9 July 2012, accepted 7 October 2012
Chang H, Yanachkov IB, Dix EJ, Li YF, Barnard MR, Wright GE, Michelson AD, Frelinger AL 3rd. Modified diadenosine tetraphosphates with dual specificity for P2Y1 and P2Y12 are potent antagonists of ADP-induced platelet activation. J Thromb Haemost 2012; 10: 2573–80.
Summary. Background: Diadenosine 5′,5′′′-P1,P4-tetraphosphate (Ap4A), a natural compound stored in platelet dense granules, inhibits ADP-induced platelet aggregation. Ap4A inhibits the platelet ADP receptors P2Y1 and P2Y12, is a partial agonist of P2Y12, and is a full agonist of the platelet ATP-gated ion channel P2X1. Modification of the Ap4A tetraphosphate backbone enhances inhibition of ADP-induced platelet aggregation. However, the effects of these Ap4A analogs on human platelet P2Y1, P2Y12 and P2X1 are unclear. Objective: To determine the agonist and antagonist activities of diadenosine tetraphosphate analogs towards P2Y1, P2Y12, and P2X1. Methods: We synthesized the following Ap4A analogs: P1,P4-dithiotetraphosphate; P2,P3-chloromethylenetetraphosphate; P1-thio-P2,P3-chloromethylenetetraphosphate; and P1,P4-dithio-P2,P3-chloromethylenetetraphosphate. We then measured the effects of these analogs on: (i) ADP-induced platelet aggregation; (ii) P2Y1-mediated changes in cytosolic Ca2+; (iii) P2Y12-mediated changes in vasodilator-stimulated phosphoprotein phosphorylation; and (iv) P2X1-mediated entry of extracellular Ca2+.Results: Ap4A analogs with modifications in the phosphate backbone inhibited both P2Y1 and P2Y12, and showed no agonist activity towards these receptors. The dithio modification increased inhibition of P2Y1, P2Y12, and platelet aggregation, whereas the chloromethylene modification increased inhibition of P2Y12 and platelet aggregation, but decreased P2Y1 inhibition. Combining the dithio and chloromethylene modifications increased P2Y1 and P2Y12 inhibition. As compared with Ap4A, each modification decreased agonist activity towards P2X1, and the dual modification completely eliminated P2X1 agonist activity. Conclusions: As compared with Ap4A, tetraphosphate backbone analogs of Ap4A have diminished activity towards P2X1 but inhibit both P2Y1 and P2Y12 and, with greater potency, inhibit ADP-induced platelet aggregation. Thus, diadenosine tetraphosphate analogs with dual receptor selectivity may have potential as antiplatelet drugs.