Figure 3. Signalling pathways mediating the effects of HDL on endothelial NO production.

HDL has been shown to stimulate endothelial NO synthase phosphorylation at serine residue 1177 via binding of apoA-I to SR-BI and binding of HDL-associated lysophospholipids to the S1P3 receptor. In addition, HDL-mediated efflux of 7-oxysterols via endothelial ABCG-1 has been observed to inhibit the interaction between eNOS and caveolin, and to prevent the loss of eNOS dimerization induced by reactive oxygen species in the endothelium.