Therapeutic activation of endothelial sphingosine 1-phosphate receptor-1 by chaperone-bound S1P suppresses proliferative retinal vasculopathy
Sphingosine-1-phosphate (S1P), a bioactive lipid mediator that signals via G protein-coupled S1P receptors (S1PR), is required for normal vascular development. The role of this signaling axis in vascular retinopathies is largely unexplored. Here we show in a mouse model of oxygen-induced retinopathy (OIR) that endothelial overexpression of S1pr1 suppresses while endothelial knockout (KO) of S1pr1 worsens neovascular tuft formation. Furthermore, neovascular tufts are increased in Apom KO mice which lack HDL-bound S1P while they are suppressed in Apom TG mice which has more circulating HDL-S1P. These results suggest that circulating HDL-S1P activation of endothelial S1PR1 specifically suppresses proliferative retinal vasculopathy. Moreover, systemic administration of ApoM-Fc-bound S1P or a small molecule Gi-biased S1PR1 agonist suppressed neovascular tuft formation. Circulating HDL-S1P activation of endothelial S1PR1 may be a key protective mechanism to guard against neovascular retinopathies that occur not only in premature infants but also in diabetes and aging.