LXR ligands inhibited platelet aggregation and calcium mobilization stimulated by collagen or CRP. Washed human platelets (4 × 108 cells/mL) were preincubated with GW3965, T0901317, or DMSO (0.04% volume/volume) for 10 minutes and stimulated with collagen (A-C). Aggregation was measured as change in light transmission and monitored for 360 seconds. (Ai,Bi) Representative aggregation traces of platelets treated with a range of GW3965 (1-20μM) (Ai) or T0901317 (10-50μM) (Bi) concentrations or DMSO followed by collagen stimulation (0.5 μg/mL). (Aii,Bii) Data are plotted as percentage of aggregation (vehicle-treated representing 100% aggregation) and represent mean plus or minus SEM values. (C) Aggregation traces of platelets stimulated by 5 μg/mL collagen (Ci) or 25 μg/mL collagen (Cii) after pretreatment with 20μM GW3965 or DMSO. (Ciii) Inhibition of aggregation by 20μM GW3965 was measured over a range (0.5-25 μg/mL) of collagen. Data are plotted as amplitude of aggregation in centimeters at 360 seconds after addition of collagen concentrations. (D) Fluo-4NW-loaded platelets were incubated with GW3965 (20μM) or DMSO (0.04%) for 10 minutes and then stimulated with CRP (2.5 μg/mL) for 200 seconds, and intracellular mobilization of calcium was measured by spectrofluorimetry. n ≥ 3. *P < .05. **P < .01.
