Erythropoietin and bone morphogenetic protein 7 mediate ascorbate-induced dopaminergic differentiation from embryonic mesencephalic precursors.

Mesencephalic precursors derived from early (embryonic day 12; E12) rat embryos were grown in vitro using mitogen basic fibroblast growth factor (bFGF) and these cells efficiently differentiated into dopaminergic (DA) neurons. However, this in vitro DA differentiation was poor in mesencephalic precursors isolated from later embryos (E13-15). Ascorbate (AA) treatment enhanced yields of DA neurons from E12 precursors, and increased the number of DA neurons generated from E13 precursors to levels attained when using E12 precursors. AA markedly up-regulated expression of bone morphogenetic protein 7 (BMP7) and erythropoietin (Epo) in precursors, but did not affect expression of a number of genes known to regulate midbrain DA development. The addition of these recombinant proteins or blockers revealed that both BMP7 and Epo mediate AA-induced DA neuron differentiation.