miR-124 represses ROCK1 expression to promote neurite elongation through activation of the PI3K/Akt signal pathway.

Recent studies have demonstrated an important role for miR-124, the most abundant and well-conserved brain-specific microRNA(miRNA), in promoting neurite outgrowth and elongation during neuronal differentiation. This miRNA's target genes and the mechanisms that execute this role remain unclear. In this study, we identified ROCK1, a small GTPase Rho kinase, as a direct target of miR-124 for regulating neurite elongation. miR-124 significantly inhibited ROCK1 expression in M17 cells. Inhibiting ROCK1 promoted neurite elongation, and the overexpression of ROCK1 strongly repressed the neurite elongation-enhancing effect of miR-124 in M17 cells. We determined that Akt functions as a novel ROCK1 downstream effector in regulating neurite outgrowth and elongation.