Abstract
PGE(2) plays a critical role in angiogenesis, ischemic, and neuro-inflammatory disorders of the brain, which breakdown the blood-brain barrier (BBB). However, the effects of PGE(2) on human brain endothelial cell (HBECs) migration, a key process in the angiogenic response and BBB stability, are not well defined. In this study, we investigated the mechanism of PGE(2) in HBECs migration in vitro. Here we showed that PGE(2) stimulated migration of HBECs in a dose-time and matrix-dependent manner, evaluated by the Boyden chamber assay, but other prostanoids failed to do so. PGE(2) receptor (EP2; butaprost), EP3 (sulprostone), and EP4 (PGE(1)-OH) receptor agonists stimulated HBECs migration, but the silencing of EP significantly attenuated this effect. EP1 agonist (11-trinor PGE(1)) had no effect on HBECs migration on silencing of the EP1 receptor. We further showed that PGE(2) stimulated cAMP production and activated protein kinase A (PKA), whereas pretreatment with the adenyl cyclase inhibitor (dideoxyadenosine; 1 mu M) or PKA inhibitors, H89 (0.5 mu M)/PKAI (1 mu M), completely abrogated PGE(2)-induced migration. Furthermore, silencing of the EP2/EP4 receptors significantly inhibited PGE(2)-induced cAMP and PKA activation, whereas EP3 receptor silencing failed to do so. These results suggest that PGE(2) regulates HBEC migration via cooperation of EP2, EP3, and EP4 receptors. Coupling of PGE(2) to these receptors resulted in increased production of cAMP, which regulates HBEC migration via PKA pathway. The elucidation of molecular events involved is critical for the development of targeted strategies to treat cerebrovascular diseases associated with dysregulated angiogenesis.