S1PR2 antagonist alleviates oxidative stress-enhanced brain endothelial permeability by attenuating p38 and...

Both sphingosine-1-phosphate receptor-2 (S1PR2) and cytosolic phospholipase A₂ (cPLA₂) are implicated in the disruption of cerebrovascular integrity in experimental stroke. However, the role of S1PR2 in induction of cPLA₂ phosphorylation during cerebral ischemia-induced endothelial dysfunction remains unknown. This study investigated the effect of S1PR2 blockade on oxidative stress-induced cerebrovascular endothelial barrier impairment and explored the possible mechanisms. In bEnd3 cells, cPLA₂ inhibitor CAY10502 as well as S1PR2 antagonist JTE013 profoundly suppressed hydrogen peroxide (H₂O₂)-induced changes of paracellular permeability and ZO-1 localization. Besides p38, extracellular signal-regulated kinase (Erk) 1/2 is required for H₂O₂-increased cPLA₂ phosphorylation and endothelial permeability. Pharmacological and genetic inhibition of S1PR2 significantly suppressed their phosphorylation in response to H₂O₂. Especially lentivirus-mediated knockdown of S1PR2 inhibited H₂O₂-induced ZO-1 redistribution and paracellular hyperpermeability. Using the permanent middle cerebral artery occlusion (pMCAO) mouse model, we found JTE013 pretreatment markedly reduced Evans blue dye (EBD) extravasation and reversed the decrease in VE-cadherin, occludin, claudin-5 and CD31 expression in infarcted hemisphere. Lentivirus-mediated S1PR2 knockdown also attenuated EBD extravasation. Furthermore, JTE013 pretreatment attenuated neurological deficit, brain edema and infarction volume. Therefore, our findings suggest the protective effect of JTE013 on brain endothelial barrier integrity is likely mediated by suppressing p38 and Erk1/2-dependent cPLA₂ phosphorylation under oxidative stress.