Abstract
AIM: The bioactive lipid, sphingosine-1-phosphate (S1P), has various roles in the physiology and pathophysiology of many diseases. There are five S1P receptors; however, the role of each S1P receptor in atherogenesis is still obscure. Here we investigated the contribution of S1P receptor 2 (S1P2) to atherogenesis by using a specific S1P2 antagonist, ONO-5430514, in apolipoprotein E-deficient (Apoe(-/-) ) mice. METHODS: Apoe(-/-) mice fed with a western-type diet (WTD) received ONO-5430514 (30 mg/kg/day) or vehicle. To examine the effect on atherogenesis, Sudan IV staining, histological analysis, qPCR, and vascular reactivity assay was performed. Human umbilical vein endothelial cells (HUVEC) were used for in vitro experiments. RESULTS: WTD-fed Apoe(-/-) mice had significantly higher S1P2 expression in the aorta compared with wild-type mice. S1P2 antagonist treatment for 20 weeks reduced atherosclerotic lesion development (p＜0.05). S1P2 antagonist treatment for 8 weeks ameliorated endothelial dysfunction (p＜0.05) accompanied with significant reduction of lipid deposition, macrophage accumulation, and inflammatory molecule expression in the aorta compared with vehicle. S1P2 antagonist attenuated the phosphorylation of JNK in the abdominal aorta compared with vehicle (p＜0.05). In HUVEC, S1P promoted inflammatory molecule expression such as MCP-1 and VCAM-1 (p＜0.001), which was attenuated by S1P2 antagonist or a JNK inhibitor (p＜0.01). S1P2 antagonist also inhibited S1P-induced JNK phosphorylation in HUVEC (p＜0.05). CONCLUSIONS: Our results suggested that an S1P2 antagonist attenuates endothelial dysfunction and prevents atherogenesis. S1P2, which promotes inflammatory activation of endothelial cells, might be a therapeutic target for atherosclerosis.