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The mechanism of blood-brain barrier (BBB) disruption, involved in poststroke edema and hemorrhagic transformation, is important but elusive. We investigated microRNA-150 (miR-150)-mediated mechanism in the disruption of BBB after stroke in rats. We found that up-regulation of miR-150 increased permeability of BBB as detected by MRI after permanent middle cerebral artery occlusion in vivo as well as increased permeability of brain microvascular endothelial cells after oxygen-glucose deprivation in vitro. The expression of claudin-5, a key tight junction protein, was decreased in the ischemic boundary zone after up-regulation of miR-150. We found in brain microvascular endothelial cells that overexpression of miR-150 decreased not only cell survival rate but also the expression levels of claudin-5 after oxygen-glucose deprivation. With dual-luciferase assay, we confirmed that miR-150 could directly regulate the angiopoietin receptor Tie-2. Moreover, silencing Tie-2 with lentivirus-delivered small interfering RNA reversed the effect of miR-150 on endothelial permeability, cell survival, and claudin-5 expression. Furthermore, poststroke treatment with antagomir-150, a specific miR-150 antagonist, contributed to BBB protection, infarct volume reduction, and amelioration of neurologic deficits. Collectively, our findings suggested that miR-150 could regulate claudin-5 expression and endothelial cell survival by targeting Tie-2, thus affecting the permeability of BBB after permanent middle cerebral artery occlusion in rats, and that miR-150 might be a potential alternative target for the treatment of stroke.-Fang, Z., He, Q.-W., Li, Q., Chen, X.-L., Baral, S., Jin, H.-J., Zhu, Y.-Y., Li, M., Xia, Y.-P., Mao, L., Hu, B. MicroRNA-150 regulates blood-brain barrier permeability via Tie-2 after permanent middle cerebral artery occlusion in rats.
Fang et al. (Wed,) studied this question.