Fibrin formation ex vivo by oxLDL is prevented by inhibiting CD36, ERK5, and apoptotic caspases. (A) Human platelets (3 × 10⁸/mL) were pretreated with the fibrin polymerization inhibitor GPRP or PSer inhibitor annexin V before stimulating with 0.1 U/mL THR with 500 ng/mL CVX. (B) Platelets were stimulated with PBS, 50 μg/mL LDL or oxLDL alone. (C) Platelets were sensitized with 50 μg/mL oxLDL followed by 250 ng/mL CVX stimulation or stimulated with 250 ng/mL CVX alone. Platelets were treated with the 1 µg/mL CD36-blocking FA6 or IgG antibody (D), DMSO (0.5%), 10 µM MEK5/ERK5 inhibitor BIX02188 or XMD8-92 (E), or with 100 µM caspase inhibitor Z-VAD–FMK (F) before stimulating with 250 ng/mL CVX alone or 50 μg/mL oxLDL with CVX; 0.1 U/mL THR with 500 ng/mL CVX stimulation was used as a control for Z-VAD–FMK treatment in panel F. Fibrin polymerization was measured at 405 nm absorbance over time with at least 3 separate donors per stimulation. Data represented as mean ± SEM. N of >3 different donors in panels A-F.