Aim: To explore the expression and role of Notch1 gene in the differentiation of the human embryonic neural stem cells to neurons induced by all-trans-retinoic-acid(ATRA).
Methods: The human embryonic neural stem cells were induced with various concentrations of ATRA(0.5, 1, 5 and 10 mumol/L) in vitro. Immunofluorescence staining was performed after seven days, and neurons were quantified by counting NSE positive cells. Then human embryonic neural stem cells were induced to differentiate with 1 mumol/L ATRA. Total RNA was extracted from the cells before inducing, induced for 3 days, and for 7 days. The expression of Notch1 gene was tested by semi-quantitative RT-PCR.
Results: The ratio of neural stem cells to differentiate to neurons was improved greatly by ATRA induction as compared with control group (P<0.01). 1 mumol/L ATRA was the optimal dose for induction of the human embryonic neural stem cell differentiation. The percentage of neurons induced by 1 micromol/L ATRA was (29.20+/-1.09)%. The expression of Notch1 gene decreased significantly after being treated with ATRA(P<0.001).
Conclusion: ATRA can greatly increase the percentage of neurons in the course of inducing the human embryonic neural stem cells to differentiate. Notch1 gene is down-regulated when human embryonic neural stem cells differentiate into neurons.