MicroRNA expression profiles of neural stem cells following valproate inducement

Neural stem cells (NSCs) possess self-renewal and multilineage differentiation ability, thus are considered to be a potential source for cell replacement therapy of many nervous system diseases, such as neurodegenerative diseases. Valproate (VPA), a member of histone deacetylase inhibitor family, is an epigenetic regulator and can promote NSCs to differentiate into neurons, nevertheless, the underlying mechanisms of the process remain unclear. MicroRNAs (miRNAs) exert a crucial part in the posttranscriptional regulation of gene expression. Epigenetic mechanisms involve in the regulation of miRNAs expression. Therefore we speculated that miRNAs may be important factors during the promotion of neuronal differentiation by VPA. Here, after selecting appropriate concentration and treatment time of VPA, we conducted microRNA arrays at 24h on the treatment of 1mM VPA or vehicle. After validation, we obtained 5 significantly upregulated miRNAs (miR-29a-5p, miR-674-5p, miR-155-5p, miR-652-3p, and miR-210-3p) in VPA group compared with control. We predicted the target genes of these miRNAs on the website. Through gene ontology (GO) and pathway analyses, we obtained preliminary comprehension of the function of these genes. The bioinformatics analyses indicated the involvement of them during neurogenesis. In addition, we observed high expression of miR-210-3p, miR-29a-5p, and miR-674-5p in central nervous system, which suggested that they were likely to play crucial roles in neuronal differentiation. We then defined the upregulation of Map2 by transfecting mimic of miR-674-5p, which indicated the promotion of miR-674-5p on NSCs differentiation. The present study explored the miRNAs potentially mediated the function of VPA on promoting NSCs to differentiate into neurons.