MiR-124 regulates apoptosis in hypoxia-induced human brain microvessel endothelial cells through targeting Bim

Human brain microvessel endothelial cells (HBMECs) are crucial for brain vascular repair and maintenance. The high-expressed expressions of microRNA-124 (miR-124) in brain have been investigated and revealed in many researches. In this work, we aimed to investigate the role of miR-124 in apoptosis of HBMECs and the underlying mechanism. Here, we found the low-expressed miR-124 in hypoxia-induced HBMECs using qRT-PCR analysis. MiR-124 targeting 3′-untranslated region (3′-UTR) of Bim mRNA was predicted by Targetscan database. Importantly, the decreased miR-124 expression and increased Bim expression, an opposite trend, were obtained in hypoxia-induced HBMECs. The further confirmation of the correlation between miR-124 and Bim was conducted by miR-124 overexpression and dual luciferase reporter assays. The inhibitory role of miR-124 in Bim expression was evidenced by results obtained from miR-124 overexpression analysis. Luciferase reporter assay further proved that miR-124 directly targeted the two conserved seed sites in the Bim 3′-UTR. The inhibited apoptosis of HBMECs was observed under both miR-124 overexpression and Bim knockdown condition in flow cytometry analysis. Collectively, these findings outline that miR-124 regulates apoptosis in hypoxia-induced HBMECs through targeting Bim, providing a better understanding of the role of miR-124 in apoptosis of HBMECs.