ABCA1 and atherosclerosis: Proprotein convertase subtilisin kexin 9 promoted lipid accumulation by inhibiting ATP binding cassette transporter A1 and G1 (ABCA1 and ABCG1), mediated cholesterol efflux from macrophages and accelerated atherosclerosis with HHcy.[66] HHcy also stimulated an increase in M1/M2 macrophage ratio, leading to more inflammatory features.