PCSK9 induces endothelial cell apoptosis through the Bcl-2/Bax–Caspase9–Caspase3 mitochondrial pathway and the p38/JNK/MAPK signaling pathway to alter the integrity of the endothelium, ultimately promoting endothelial dysfunction and the development of atherosclerosis. The gene discussed is MAPK8; the disease is atherosclerosis.