Abstract
Research on neural stem cells (NSCs) has recently focused on microRNAs (miRNAs), a class of small non‑coding RNAs that have crucial roles in regulating NSC proliferation and differentiation. In the present study, a quantitative‑polymerase chain reaction assay revealed that the expression of miRNA (miR)‑138‑5p was significantly decreased during neural differentiation of NSCs in vitro. Overexpression of miR‑138‑5p reduced NSC proliferation and increased NSC differentiation. Furthermore, suppression of miR‑138‑5p via transfection with a miRNA inhibitor enhanced NSC proliferation and attenuated NSC differentiation. Additionally, expression of thyroid hormone receptor interacting protein 6 (TRIP6), a critical regulator of NSCs, was negatively correlated with the miR‑138‑5p level. A luciferase assay demonstrated that miR‑138‑5p regulate TRIP6 by directly binding the 3'‑untranslated region of the mRNA. Additionally, upregulation of TRIP6 rescued the NSC proliferation deficiency induced by miR‑138‑5p and abolished miR‑138‑5p‑promoted NSCs differentiation. By contrast, downregulation of TRIP6 produced the opposite effect on proliferation and differentiation of NSCs transfected with anti‑miR‑138‑5p. Taken together, the data suggest that miR‑138‑5p regulates NSCs proliferation and differentiation, and may be useful in developing novel treatments for neurological disorders via manipulation of miR‑138‑5p in NSCs.