Abstract
Although maternal intake of folic acid (FA) prevents neural tube defects in 70% of the population, the exact mechanism of prevention has not been elucidated. We hypothesized that FA affects neural stem cell (NSC) proliferation and differentiation. This hypothesis was examined in a folate-responsive spina bifida mouse model, Splotch (Sp(-/-)), which has a homozygous loss-of-function mutation in the Pax3 gene. Neurospheres were generated with NSCs from the lower lumbar neural tube of E10.5 wild-type (WT) and Sp(-/-) embryos, in the presence and absence of FA. In the absence of FA, the number of neurospheres generated from Sp(-/-) embryos compared with WT was minimal (P<0.05). addition of fa to sp(- -) cultures increased the expression of a pax3 downstream target, fgfr4, and rescued nsc proliferative potential, as demonstrated by a significant increase in neurosphere formation (p><0.01). to ascertain if fa affected cell differentiation, fa-stimulated sp(- -) neurospheres were allowed to differentiate in the continued presence or absence of fa. neurospheres from both conditions expressed multi-potent stem cell characteristics and the same differentiation potential as wt. further, multiple neurospheres from both wt and fa-stimulated sp(- -) cell cultures formed extensive synaptic connections. on the whole, fa-mediated rescue of neural tube defects in sp(- -) embryos promotes nsc proliferation at an early embryonic stage. fa-stimulated sp(- -) neurospheres differentiate and form synaptic connections, comparable to wt.>
