However, because S1P in HDL is responsible for many pleiotropic functions of HDL, a low S1P level is a critical characteristic of HDL dysfunction in CAD.65 ApoM affects the biological functions of S1P, and ApoM-bound S1P exerts more potent effects on S1P1 in endothelial cells.30,60,66 Here, we showed that ApoM enhanced the inhibitory effect of S1P on HDRACA in endothelial cells. Here, S1PR1 is linked to coronary artery disorder.