Platelet signalling networks: pathways perturbation demonstrates differential sensitivity of ADP secretion and fibinogen binding.

Platelet signalling responses to single agonists have been identified previously. However a model of the total platelet signalling network is still lacking. In order to gain insights into this network, we explored the effects of a range of platelet-function inhibitors in two independent assays of platelet function, namely fibrinogen binding and ADP secretion. In this study, we targeted the intracellular signalling molecules Syk and PI3K, the prostaglandin synthesis enzyme COX, surface receptors for TxA₂ and ADP (P2Y1 and P2Y12) and the integrin cell adhesion molecule, aIIbb3. We demonstrate that the platelet responses of fibrinogen binding and secretion can be differentially affected by the individual inhibitors permitting the generation of a model delineating novel regulatory links in the platelet signal network. Importantly, the model illustrates the interconnections among portions that are traditionally studied as separate modules, promoting a more integrated view of the platelet.