S1P triggers cerebral vessel constriction through the store‐operated calcium entry pathway

Abstract

ObjectiveTo characterize signaling pathways by which sphingosine‐1‐phosphate (S1P) modulates vascular tone.MethodsThe role of store‐operated calcium entry (SOCE) in S1P‐induced Ca2+ entry in vascular smooth muscle cells (VSMCs) and vessel constriction was assessed using ratiometric Ca2+ measurements, quantitative RT‐PCR and isolated arteries.ResultsIn VSMCs, S1P triggered STIM1 puncta formation, and SOCE activated by S1P was inhibited by 2‐aminoethoxydiphenylborate (2‐APB), diethylstilbestrol and gadolinium. In VSMCs prepared from S1P3 receptor knockout mice, the initial calcium rise triggered by S1P was abolished, but SOCE was still present suggesting that S1P acts via multiple signaling pathways. S1P‐induced SOCE was larger in proliferative than in contractile VSMCs, correlating with increases in STIM1, Orai1, S1P1 and S1P3 receptor mRNA. STIM1, S1P1 and S1P3 receptor mRNA expression were larger in freshly isolated brain vessels than in aorta. These data, and the fact that 2‐APB inhibits S1P‐induced cerebral artery constriction, suggest that SOCE modulates S1P‐induced vasoconstriction in vivo.ConclusionThese data support a role for SOCE in S1P induced calcium entry and vessel constriction. The relationship between increased S1P signaling and SOCE in proliferative VSMCs suggests a role of S1P in disorders associated with vascular proliferation, such as atherosclerosis or vasospasm.