Transcriptional factor FoxM1-activated microRNA-335-3p maintains the self-renewal of neural stem cells by inhibiting p53 signaling pathway via Fmr1

Abstract

Background: New mechanistic insights into the self-renewal ability and multipotent properties of neural stem cells (NSCs) are currently under active investigation for potential use in the treatment of neurological diseases. In this study, NSCs were isolated from the forebrain of fetal rats and cultured to induce NSC differentiation, which was associated with low expression of the non-coding RNA microRNA-335-3p (miR-335-3p). Methods: Loss- and gain-of-function experiments were performed in NSCs after induction of differentiation. Results: Overexpression of miR-335-3p or FoxM1 and inhibition of the Fmr1 or p53 signaling pathways facilitated neurosphere formation, enhanced proliferation and cell cycle entry of NSCs, but restricted NSC differentiation. Mechanistically, FoxM1 positively regulated miR-335-3p by binding to its promoter region, while miR-335-3p targeted and negatively regulated Fmr1. Additionally, the promotive effect of miR-335-3p on NSC self-renewal occurred via p53 signaling pathway inactivation. Conclusion: Taken together, miR-335-3p activated by FoxM1 could suppress NSC differentiation and promote NSC self-renewal by inactivating the p53 signaling pathway via Fmr1.