Tissue-Specific Stem Cells Neural precursors derived from embryonic stem cells, but not those from fetal ventral mesencephalon, maintain the potential to differentiate into dopaminergic neurons after expansion in vitro

Neural precursors derived from embryonic stem cells, but not those from fetal ventral mesencephalon, maintain the potential to differentiate into dopaminergic neurons after expansion in vitro ABSTRACT Neural precursors (NP) derived from ventral mesencephalon (VM) normally generate dopaminergic (DA) neurons in vivo but lose their potential to differentiate into DA neurons during mitogenic expansion in vitro, hampering their efficient use as a transplantable and experimental cell source. Since ES cell-derived NPs (ES NP) do not go through the same maturation process during in vitro expansion, we hypothesized that expanded ES NPs may maintain their potential to differentiate into DA neurons. To address this, we expanded NPs derived from mouse E12.5 VM or ES cells, and compared their developmental properties. Interestingly, expanded ES NPs fully sustain their ability to differentiate to the neuronal as well as to the dopaminergic fate. In sharp contrast, VM NPs almost completely lost their ability to become neurons and TH + neurons following expansion. Expanded ES NP-derived TH + neurons coexpressed additional DA markers such as DDC and DAT. Furthermore, they also expressed other midbrain DA markers, including Nurr1 and Pitx3 and released significant amounts of DA. We also found that these ES NPs can be cryopreserved without losing their proliferative and developmental potential. Finally, we tested the in vivo characteristics of the expanded NPs derived from J1 ES cells with low passage number. When transplanted into the mouse striatum, the expanded NPs as well as control NPs efficiently generated DA neurons expressing mature DA markers, with about 10% tumor formation in both cases. Taken together, we conclude that ES NPs maintain their developmental potential during in vitro expansion, while mouse E12.5 VM NPs don't.