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.

中文翻译：

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S1PR2拮抗剂通过减弱p38和Erk1 / 2依赖性cPLA2磷酸化来减轻氧化应激增强的脑内皮细胞通透性。

鞘氨醇-1-磷酸受体2（S1PR2）和胞质磷脂酶A2（cPLA2）均与实验性卒中中脑血管完整性的破坏有关。然而，S1PR2在脑缺血诱导的内皮功能障碍过程中诱导cPLA2磷酸化的作用仍然未知。这项研究调查了S1PR2阻断对氧化应激诱导的脑血管内皮屏障损害的影响，并探讨了可能的机制。在bEnd3细胞中，cPLA2抑制剂CAY10502和S1PR2拮抗剂JTE013能够显着抑制过氧化氢（H2O2）诱导的旁细胞通透性变化和ZO-1定位。除p38外，H2O2增加的cPLA2磷酸化和内皮通透性还需要细胞外信号调节激酶（Erk）1/2。S1PR2的药理和遗传抑制作用显着抑制了其对H2O2的磷酸化。尤其是慢病毒介导的S1PR2的敲低抑制了H2O2诱导的ZO-1重新分布和细胞旁通透性。使用永久性大脑中动脉闭塞（pMCAO）小鼠模型，我们发现JTE013预处理可显着减少伊文思蓝染料（EBD）外渗，并逆转梗塞性半球中VE-钙黏着蛋白，闭合蛋白，claudin-5和CD31的表达下降。慢病毒介导的S1PR2敲低也减弱了EBD外渗。此外，JTE013预处理可减轻神经功能缺损，脑水肿和梗塞体积。所以，