Abstract
SUMMARY Current protocols for the differentiation of cardiomyocytes from human induced pluripotent stem cells (iPSCs) generally require prolonged time in culture and result in heterogeneous cellular populations. We present a method for the generation of beating cardiomyocytes expressing specific ventricular markers after just 14 days. Addition of the pan-retinoic acid receptor inverse agonist BMS 493 to human iPSCs for the first 8 days of differentiation resulted in increased protein expression of the ventricular isoform of myosin regulatory light chain (MLC2V) from 18.7% ± 1.72% to 55.8% ± 11.4% (p <0.0001) in cells co-expressing the cardiac muscle protein troponin T (TNNT2). Increased MLC2V expression was also accompanied by a slower beating rate (49.4 ± 1.53 vs. 93.0 ± 2.81 beats per minute, p <0.0001) and increased contraction amplitude (201% ± 8.33% vs. 100% ± 10.85%, p <0.0001) compared to untreated cells. Improved directed differentiation will improve in vitro cardiac modeling.
