CRISPR activation enables high fidelity reprogramming into human pluripotent stem cells (bulk cells)

Conventional reprogramming methods rely on the ectopic expression of transcription factors to reprogram somatic cells into induced pluripotent stem cells (iPSC). Forced expression of transcription factors might lead to off-target gene activation and heterogeneous reprogramming, resulting in the emergence of alternative cell types and aberrant iPSC. Activation of endogenous pluripotency factors by CRISPR activation (CRISPRa) can potentially reduce this heterogeneity. Here we describe a high efficiency reprogramming of human somatic cells into iPSC using optimized CRISPRa. Efficient reprogramming was dependent on the additional targeting of the embryo genome activation-enriched Alu-motif and the miR-302/367 locus. Single-cell transcriptome analysis revealed that the optimized CRISPRa reprogrammed cells with more directly and specifically into the pluripotent state when compared to the conventional reprogramming method. These findings support the use of CRISPRa for high quality reprogramming of human iPSC. Overall design: Transcriptomic analysis of ten LCL and five fibroblast derived human iPSC lines generated by CRISPR activation method