In vivo differentiation of induced pluripotent stem cells into neural stem cells by chimera formation

Like embryonic stem cells, induced pluripotent stem cells (iPSCs) can differentiate into all three germ layers in an in vitro system. Here, we developed a new technology for obtaining neural stem cells (NSCs) from iPSCs through chimera formation, in an in vivo environment. iPSCs contributed to the neural lineage in the chimera, which could be efficiently purified and directly cultured as NSCs in vitro. The iPSC-derived, in vivo-differentiated NSCs expressed NSC markers, and their gene-expression pattern more closely resembled that of brain-derived NSCs than in vitro-differentiated NSCs. This system could be applied for differentiating pluripotent stem cells into specialized cell type whose differentiation protocols are not well established. Brain-NSCs (from 13.5dpc fetuses, ROSA26/OG2 heterozygous double transgenic), iPS-NSCs #1, #3 (In vitro differentiated), iPS-cNSCs (In vivo differentiated, chimeric), NED-NSCs (normal embryo-derived), MEFs (from 13.5dpc fetuses, ROSA26/OG2 heterozygous double transgenic), and ESCs (OG2 heterozygous double transgenic) were used for analysis.