miR-124 promotes the neuronal differentiation of mouse inner ear neural stem cells.

MicroRNAs (miRNAs or miRs) act as key regulators in neuronal development, synaptic morphogenesis and plasticity. However, their role in the neuronal differentiation of inner ear neural stem cells (NSCs) remains unclear. In this study, 6 miRNAs were selected and their expression patterns during the neuronal differentiation of inner ear NSCs were examined by RT-qPCR. We demonstrated that the culture of spiral ganglion stem cells present in the inner ears of newborn mice gave rise to neurons in vitro. The expression patterns of miR‑124, miR‑132, miR‑134, miR‑20a, miR‑17-5p and miR‑30a-5p were examined during a 14-day neuronal differentiation period. We found that miR‑124 promoted the neuronal differentiation of and neurite outgrowth in mouse inner ear NSCs, and that the changes in the expression of tropomyosin receptor kinase B (TrkB) and cell division control protein 42 homolog (Cdc42) during inner ear NSC differentiation were associated with miR‑124 expression. Our findings indicate that miR‑124 plays a role in the neuronal differentiation of inner ear NSCs. This finding may lead to the development of novel strategies for restoring hearing in neurodegenerative diseases.