Figure 4.
Positive feedback regulation of FPR2/ALX in platelets. The effects of different concentrations of WRW4 on CRP-XL– (0.25 µg/mL) (A) or ADP-induced (2 µM) (B) human platelet aggregation was analyzed by optical aggregometry. (C) The level of adenosine triphosphate (ATP) secretion in human platelets (PRP) treated with WRW4 prior to activation with CRP-XL (0.25 µg/mL) was measured by lumi-aggregometry. The levels of fibrinogen binding (i) and P-selectin exposure (ii) were analyzed in platelets obtained from control or Fpr2/3−/− mice upon stimulation with various concentrations of CRP-XL (D), ADP (E), AY-NH2 (F), or U46691 (G) by flow cytometry. Data represent mean ± SEM (n = 3). P values shown are as calculated by 2-way ANOVA followed by Bonferroni's correction in most of the experiments except for the data shown in panels A-C, which were analyzed by 1-way ANOVA followed by Bonferroni's correction (*P < .05; **P < .01).