Abstract
Differentiation to dopamine(DA)ergic neurons from ES cells was induced by 5 steps: stage 1, maintenance of ES cells; stage 2, embryoid body formation; stage 3, selection of nestin-positive cells; stage 4, expansion of nestin-positive neural stem cells (NSCs); stage 5, induction to DAergic neurons. To investigate how to induce DAergic differentiation from ES-derived NSCs, physiological low oxygen (3.5% O2) in development or increased factors in the DA-depleted striatum (cytokine cocktail: IL-1β, IL-11, LIF, GDNF) was treated to NSCs. Treatment of cytokine cocktail or 3.5% O2 increased the number of tyrosine hydroxylase (TH)-positive cells as compared to controls (2.20 -fold or 1.83-fold respectively). However, combination of low O2 with cytokine cocktail did not show any additive effect. Furthermore, treatment of IL-1β and LIF showed most of the effect of cytokine cocktail. To investigate how cytokine cocktail induces DAergic differentiation, we focused on the effect of hypoxia inducible factor (HIF)-1α. Cytokine cocktail increased the expression of HIF-1α that is known as an activator of TH promoter. Inhibition of HIF-1αexpression by antisense treatment to LIF and IL-1β-treated NSCs decreased the number of TH-positive cells. Data suggest that enhanced differentiation to DAergic neurons from ES-derived NSCs by physiological low O2 in development or increased cytokines in injured brain was mediated by increased expression of HIF-1α. [J Physiol Sci. 2007;57 Suppl:S132]
