MicroRNA124 Regulated Neurite Elongation by Targeting OSBP

MicroRNA-124 (miR-124), a brain-specific miRNA molecule, has been implicated in stimulating neurite outgrowth and elongation during neuronal differentiation. However, the direct target genes and the mechanisms of miR-124-induced neurite outgrowth are poorly understood. In this study, we demonstrated that miR-124 directly targeted and downregulated the endogenous expression of oxysterol-binding protein (OSBP). A previous study found that the expression of miR-124 increased during brain development. In the present study, we demonstrated that the expression of OSBP decreased during the development of the C57BL/6 mouse cortex, which was negatively correlated with miR-124 expression. OSBP knockdown using specific shRNAs promoted neurite outgrowth and elongation in both Neuro-2a cells and primary cultured mouse cortical neurons. Conversely, OSBP overexpression strongly repressed the neurite elongation-enhancing effect of miR-124 in Neuro-2a cells. Our results suggested that OSBP may be a target and downstream effector of miR-124 for regulating neurite outgrowth and elongation.