Human iPSC-derived neural stem cells display a radial glia-like signature in vitro and favorable long-term safety in transplanted mice

Human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NSCs) are a promising source of cell therapy approaches to treat neurodegenerative and demyelinating disorders. Despite ongoing efforts to characterize hiPSC-derived cells in vitro and in vivo, we lack comprehensive genome- and transcriptome-wide studies addressing hiPSC-NSC identity and safety, which are critical for establishing accepted criteria for prospective clinical applications. Here, we evaluated the transcriptional and epigenetic signatures of hiPSCs and differentiated hiPSC-NSC progeny, finding that the hiPSC-to-NSC transition results in a complete loss of pluripotency and the acquisition of a radial glia-associated transcriptional and gene regulatory signatures. Importantly, hiPSC-NSCs share with somatic human fetal NSCs (hfNSCs) the main transcriptional and epigenetic patterns associated with NSC-specific biology. In vivo, long-term observation (up to 10 months) of mice intracerebrally transplanted as neonates with hiPSC-NSCs showed robust engraftment and widespread distribution of hiPSC-NSCs in the host brain parenchyma. Engrafted hiPSC-NSCs displayed multilineage potential and preferentially generated glial cells. No hyperproliferation, tumor formation, or expression of pluripotency markers was observed. Finally, we identified a novel candidate transcription factor involved in the astroglial commitment of hiPSC-NSCs. Overall, these comprehensive in vitro and in vivo analyses clarify the cell identity and safety profile of hiPSC-NSCs, supporting their continuing development as an alternative to somatic hfNSCs in treating neurodegenerative and demyelinating disorders.