A protocol for the differentiation of human embryonic stem cells into dopaminergic neurons using only chemically defined human additives: Studies in vitro and in vivo

Our ability to use human embryonic stem (hES) cells in cell replacement therapy for Parkinson's disease depends on the discovery of ways to simply and reliably differentiate a dopaminergic (DA) phenotype in these cells. Although several protocols exist for the differentiation of DA traits in hES, they involve the prolonged use of complex media with undefined components, cell conditioned media and/or co-culture with various cells, usually of animal origin. In this study, several well-characterized (H9, BG01) and several new uncharacterized (HUES7, HUES8) hES cell lines were studied for their capacity to differentiate into DA neurons in culture using a novel rapid protocol which uses only chemically-defined human-derived media additives and substrata. Within 3 weeks, cells from all 4 cell lines progressed from the undifferentiated state to β-tubulin III positive cells expressing DA markers in vitro. Moreover, transplantation of these cells into the striata of 6-hydroxydopamine-treated rats at the neuronal progenitor stage resulted in the appearance of differentiated DA traits in vivo 2–3 weeks later.