APOE and atherosclerosis: Finally, sphingosine-1-phosphate receptor 2 (S1PR2) can be activated by various conjugated BAs and then promotes atherosclerosis by regulating macrophage retention and inflammatory cytokine secretion (Studer et al., 2012), whereas S1PR2 knockdown attenuates atherosclerosis in ApoE-/- mice (Skoura et al., 2011).