MicroRNA-107 prevents amyloid-beta induced blood-brain barrier disruption and endothelial cell dysfunction by...

The disruption of blood-brain barrier (BBB) and endothelial cell dysfunction, associated with the cerebrovascular deposition of the amyloid-beta (Abeta) protein, have been characterized as the key pathological characteristics in Alzheimer's disease (AD). In various biologic processes of AD, researchers have proven that mircroRNAs (miRNAs) play critical roles. However, the role and function of miRNAs in the disruption of BBB of AD still remain unclear. Here, we found that mircroRNA-107 (miR-107) is endogenously expressed in human brain microvascular endothelial cells (ECs) of BBB model, while it is significantly down-regulated in ECs pre-incubated with Abeta. Abeta significantly impairs the integrity, increases the permeability of BBB, inhibits the viability of endothelial cells (ECs), and meanwhile down-regulates the expression of tight junction proteins ZO-1, Occludin and Claudin-5. Overexpression of miR-107 largely abrogated Abeta-induced disruption of BBB and endothelial cell dysfunction. Furthermore, overexpression of miR-107 also down-regulates endophilin-1, which is involved in the regulation of BBB permeability and the expression of ZO-1, Occludin, and Claudin-5. Both bioinformatics and luciferase reporter assays demonstrated that Endophilin-1 was a direct and functional downstream target of miR-107. In conclusion, our results indicate that overexpression of miR-107 is able to prevent Abeta-induced blood-brain barrier disruption and endothelial cell dysfunction by targeting endophilin-1.