A synthetic DNA-binding inhibitor of SOX2 guided human induced pluripotent stem cells to differentiate into cardiac mesoderm

Targeted differentiation of human induced pluripotent stem cells (hiPSCs) using only chemicals is proclaimed to have value-added clinical potential in the regeneration of complex cell types like cardiomyocytes. Despite the availability of several small molecule inhibitors capable of modulating specific receptor-ligand interaction or enzymatic activity, no bioactive synthetic DNA-binding inhibitor targeting key cell fate-controlling gene like SOX2 is available yet. Herein, we demonstrate a novel DNA-based chemical approach to guide hiPSCs differentiation using pyrrole-imidazole polyamides (PIPs), which are sequence-selective DNA-binding synthetic molecules. Harnessing the knowledge about key transcriptional changes associated with cardiomyocyte induction, we developed a PIP termed SOX-L targeting 5′-CTTTGTT-3′ sequence and demonstrate the inhibition of SOX2-DNA interaction and mesoderm induction of hiPSCs. Genome-wide gene analyses revealed that SOX-L remarkably specified cardiac mesoderm by triggering targeted alteration in SOX2-associated gene regulatory networks. Also, employment of SOX-L along with a Wnt inhibitor successfully generated spontaneously contracting cardiomyocytes to validate our concept that DNA-binding inhibitors like PIPs could be used for directed differentiation of hiPSCs. Because PIPs could be fine-tuned to target specific DNA sequences, our DNA-based approach could be expanded to directly target and distinctively regulate key transcription factor associated with the desired cell type. Genome-wide gene expression change in 201B7 by treatment of PIP SOX-L were examined.