Effects of myr-KF7 and THO on platelet’s aggregation, binding, and spreading. (A-C) Aggregation of washed human platelets (300 × 109/L) stimulated with thrombin (0.03 U/mL; A), collagen (1 μg/mL; B), or anti-αIIb TM peptide (1 μM; C) in the presence of myr-KF7 and its scrambled peptide myr-KF7scr (50 μM). (D-F) Aggregation of washed human platelets (300 × 109/L) stimulated with thrombin (0.03 U/mL; D), collagen (1 μg/mL; E), or anti-αIIb TM peptide (1 μM; F) in the presence of THO and 0.1% DMSO. (G) The effect of myr-KF7 and THO on platelet spreading. Washed human platelets (100 × 109/L) were preincubated with myr-KF7, myr-KF7scr, and THO at 50 μM; SQ29548 at 4 μM; apyrase at 0.5 U/mL; or eptifibatide (10 μM). The platelets were allowed to spread on immobilized fibrinogen at 37°C for 40 minutes and stained with FITC-conjugated phalloidin for immunofluorescence microscopy. The bar represents 10 μm. (H) ImageJ software was used to quantify the platelets and area of spread. *P < .05; ***P < .001. (I) The effect of myr-KF7 and THO on soluble fibrinogen binding to platelets. Washed human platelets (300 × 109/L) were preincubated with myr-KF7, myr-KF7scr, and THO at 50 μM. Binding of FITC-conjugated fibrinogen (100 μg/mL) to platelets was measured by flow cytometry. (J-L) The effect of 100 μM myr-KF7 and THO on 100 μM for both PAR4AP- and collagen-induced aggregation of GPIbα−/− platelets. (M) Effect of 100 μM myr-KF7 and THO on GPIbα−/− spreading of platelets on immobilized fibrinogen.Scale bar, 10 μm.