Platelet-Derived Short-Chain Polyphosphates Enhance the Inactivation of Tissue Factor Pathway Inhibitor by Activated Coagulation Factor XI
Fig 6
FXI is required for short-chain polyphosphates to inhibit the anticoagulant effect of TFPIα in plasma.
(A) TF-induced clotting times were measured in normal plasma in the presence of increasing concentrations of TFPIα in the absence (○, ◻, △) or presence of 5 μM SCP (●, ■, ▲). Plasma was pretreated with vehicle (○,●), 20 μg/ml 1A6 (△, ▲), or 50 μg/ml 10C9 (◻,■). (B) TF-induced clotting times were measured in FIX-depleted plasma (FIX-dep) (■,●) or FXI-depleted plasma (FXI-dep) (◻,○) in the presence of increasing concentrations of TFPIα in the absence (■,◻) or presence of 5 μM SCP (○,●). (C) TF-induced clotting times were measured in FIX-depleted plasma in the presence of increasing concentrations of TFPIα in the absence (○, ◻, △) or presence of 5 μM SCP (●, ■, ▲). Plasma was pretreated with vehicle (○,●), 20 μg/ml 1A6 (△, ▲), or 50 μg/ml 10C9 (◻,■). Data are mean ± SE (n = 3).