Platelet CD36/ERK5 are key drivers of caspase activation by oxidized lipids. (A) Cleaved caspase 3 was detected by immunoblot as a marker of caspase activity after human platelets were stimulated with buffer, 50 μg/mL LDL or oxLDL, and 50 nM ABT-737 for 60 minutes; 0.1 U/mL THR with 50 ng/mL CVX for 7 minutes were used as a negative control. (B) Human platelets were treated according to panel A. The whole-cell lysate from each treatment was incubated with the caspase 3 substrate DEVD-pNa according to the manufacturer’s protocol. The slopes of p-nitroaniline absorbance were used to indicate activity. FA6-152 or an IgG control antibody (1 μg/mL) was used to determine CD36 dependency (C) and 10 μM BIX02188 was used to determine ERK5 dependency (D). Densitometric analysis of the ratio of cleaved caspase 3/procaspase 3 was indicated with each blot. Blots are representative of at least 3 separate experiments from 3 different donors in panels A-D. Data represented as mean ± SEM.