Activation of pancreatic B-cell genes by multiplex epigenetic CRISPR-editing

CRISPR-based systems for epigenetic editing are promising molecular tools that could be harnessed for directed differentiation of pluripotent stem cells. We used the CRISPR/dCas9-VP160, CRISPR/dCas9-TET1 and CRISPR/dCas9-P300 systems for multiplex epigenetic editing and activation of human beta pancreatic genes (PDX1, NEUROG3, PAX4 and INS). The CRISPR/dCas9-P300 system was the most effective at activating genes with reduced number of sgRNA. Using small number of sgRNA per gene was important to induce multiplex gene activation. Combined activation of transcription factors (TFs) involved in beta cell development resulted in INS gene expression; in which sequential TFs activation was more effective than simultaneous activation. Full CRISPR RNA-based delivery system was able to activate all targeted genes. Overall, this study shows the utility of CRISPR tools for epigenetic editing and directed cellular differentiation.