Department of Pharmacology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211116, Jiangsu, China; Jiangsu College of Nursing, 9 Science and Technology Avenue, Huaian, 223005, Jiangsu, China.
Department of Pharmacology, Nanjing Medical University, 101 Longmian Avenue, Nanjing 211116, Jiangsu, China.
Cell Signal. 2019 Jan;53:151-161. doi: 10.1016/j.cellsig.2018.09.019. Epub 2018 Oct 2.
Both sphingosine-1-phosphate receptor-2 (S1PR2) and cytosolic phospholipase A (cPLA) are implicated in the disruption of cerebrovascular integrity in experimental stroke. However, the role of S1PR2 in induction of cPLA 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, cPLA inhibitor CAY10502 as well as S1PR2 antagonist JTE013 profoundly suppressed hydrogen peroxide (HO)-induced changes of paracellular permeability and ZO-1 localization. Besides p38, extracellular signal-regulated kinase (Erk) 1/2 is required for HO-increased cPLA phosphorylation and endothelial permeability. Pharmacological and genetic inhibition of S1PR2 significantly suppressed their phosphorylation in response to HO. Especially lentivirus-mediated knockdown of S1PR2 inhibited HO-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 cPLA phosphorylation under oxidative stress.
鞘氨醇-1-磷酸受体-2（S1PR2）和细胞质型磷脂酶 A（cPLA）都与实验性中风中脑血管完整性的破坏有关。然而，S1PR2 在诱导脑缺血诱导的内皮功能障碍期间 cPLA 磷酸化中的作用仍然未知。本研究调查了 S1PR2 阻断对氧化应激诱导的脑血管内皮屏障损伤的影响，并探讨了可能的机制。在 bEnd3 细胞中，cPLA 抑制剂 CAY10502 以及 S1PR2 拮抗剂 JTE013 可显著抑制过氧化氢（HO）诱导的细胞旁通透性和 ZO-1 定位的变化。除了 p38 之外，细胞外信号调节激酶（Erk）1/2 是 HO 增加 cPLA 磷酸化和内皮通透性所必需的。S1PR2 的药理学和遗传学抑制可显著抑制其对 HO 的磷酸化。特别是，S1PR2 的慢病毒介导的敲低抑制了 HO 诱导的 ZO-1 重分布和细胞旁高通透性。使用永久性大脑中动脉闭塞（pMCAO）小鼠模型，我们发现 JTE013 预处理可显著减少 Evans 蓝染料（EBD）外渗，并逆转梗死半球中 VE-钙粘蛋白，occludin，claudin-5 和 CD31 表达的降低。慢病毒介导的 S1PR2 敲低也减轻了 EBD 外渗。此外，JTE013 预处理可减轻神经功能缺损，脑水肿和梗死体积。因此，我们的研究结果表明，JTE013 对脑内皮屏障完整性的保护作用可能是通过在氧化应激下抑制 p38 和 Erk1/2 依赖性 cPLA 磷酸化来介导的。
