An engineered Sox17 induces somatic to neural stem cell fate transition independently from pluripotency reprogramming [scRNA-seq]

Advances in molecular strategies to reprogram cell fate is a promising avenue for cell-based therapies. Methods to generate induced neural stem cells (iNSCs) are often slow with limited reprogramming events and it is unclear whether cells transit via a pluripotent state. We report an iNSC reprogramming approach from embryonic and aged mouse fibroblasts using an engineered Sox17 (eSox17FNV). eSox17FNV efficiently drives iNSC reprogramming while Sox2 or Sox17 fails to do so. eSox17FNV acquires the capacity to bind new protein partners to scan the genome more efficiently and possesses a more potent transactivation domain than Sox2. At the onset of reprogramming, in the presence of eSox17FNV, fibroblasts divert from a iPSC route towards iNSC fate. Further, lineage tracing shows that emerging iNSCs do not transit through a pluripotent state if POU factors are excluded. This reveals new molecular and physiological framework for iNSC generation and contrasts with lineage from pluripotency reprogramming. Overall design: We analyzed mouse primary NSC isolated from mouse embryos and iNSCs reprogrammed from mouse embryonic fibroblasts using transcription factor combination containing eSox17FNV by scRNA-seq.