Reprogramming of Fibroblasts to Oligodendrocyte Progenitor-like Cells Using CRISPR/Cas9-Based Synthetic Transcription Factors.

Cell lineage reprogramming via transgene overexpression of key master regulatory transcription factors has been well documented. However, the poor efficiency and lack of fidelity of this approach is problematic. Synthetic transcription factors (sTFs)-built from the repurposed CRISPR/Cas9 system-can activate endogenous target genes to direct differentiation or trigger lineage reprogramming. Here we explored whether sTFs could be used to steer mouse neural stem cells and mouse embryonic fibroblasts toward the oligodendrocyte lineage. We developed a non-viral modular expression system to enable stable multiplex delivery of pools of sTFs capable of transcriptional activation of three key oligodendrocyte lineage master regulatory genes (Sox10, Olig2, and Nkx6-2). Delivery of these sTFs could enhance neural stem cell differentiation and initiated mouse embryonic fibroblast direct reprograming toward oligodendrocyte progenitor-like cells. Our findings demonstrate the value of sTFs as tools for activating endogenous genes and directing mammalian cell-type identity.