The regulation of survival and differentiation of neural stem cells by miR-124 via modulating PAX3.

MicroRNAs (miRNAs) have crucial functions in the regulation of proliferation and differentiation of neural stem cells (NSCs). MiR-124 has been reported to be implicated in neurogenesis. However, the precise function and mechanism of miR-124 still need further verification. In this study, we identified paired box 3 (PAX3) as a potential target of miR-124 using bioinformatics approaches. Next, we found PAX3 had reversed expression pattern with miR-124 as well as TUBB3 and GFAP. Dual-luciferase assay showed that miR-124 could bind to the 3'-UTR of PAX3 mRNA and restrain its expression. It was demonstrated that overexpression and knocking down of miR-124 in NSCs could promote the survival and suppress the apoptosis of NSCs. Meanwhile, miR-124 enhanced the expression of TUBB3 and GFAP via impairing PAX3 expression. Mechanistic study revealed that augmented Akt-GSK3ß signaling pathway was the driving-force for the regulatory functions of miR-124 in NSCs. In summary, this study for the first time uncovered that miR-124 could suppress PAX3 expression, which in turn regulated the differentiation of NSCs.

Apoptosis, Expression of PAX3 and P53, and Caspase Signal in Fetuses with Neural Tube Defects.

BACKGROUND: Neural tube defects (NTDs) are among the most common and severe congenital malformations of the central nervous system. Animal studies have shown that apoptosis is involved in the development of NTDs. However, little evidence is available from human studies. We aim to examine the level of apoptosis and expression of apoptosis-regulating proteins of human terminated fetuses. METHODS: A total of 37 NTD cases and 21 controls from pregnancy terminations were recruited. Tissues of the central nervous system were obtained through autopsy. Apoptosis of neuroepithelial cells was examined by terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling (TUNEL) assay. Expression of PAX3, p53, and caspase 3/8/9 in central nervous tissue was measured using Western blotting. RESULTS: More TUNEL-positive apoptosis cells were observed in the central nervous tissue of NTD cases than those of controls (p < 0.05). In spinal cord tissue, lower PAX3 expression, higher p53 expression, and increased levels of cleaved caspase 3(17kD) and cleaved caspase 8 (18kD) were found in anencephaly cases but not in spina bifida cases when compared with controls. In brain tissue, levels of PAX3 were significantly reduced in both encephalocele and spina bifida subtypes; the expression levels of cleaved caspase 3(17 kD) of encephalocele cases and cleaved caspase 8(47/45 kD) in spina bifida cases were higher than in controls; no difference was found in the expression of p53 or caspase 9 between NTDs and controls. CONCLUSION: These findings provide some evidence that excessive apoptosis in fetal central nervous tissues may be associated with the development of human NTDs. Birth Defects Research 109:1596-1604, 2017. © 2017 Wiley Periodicals, Inc.