Simple Monolayer Differentiation of Murine Cardiomyocytes via Nutrient Deprivation-Mediated Activation of β-Catenin

Methods to generate murine cardiomyocytes from pluripotent stem cells (PSCs) in vitro are resource and time intensive. All current protocols require exogenously provided soluble factors and almost all utilize embryoid body formation to modulate pathways associated with mesoderm specification and cardiomyocyte differentiation. Here, we developed a simple protocol without EBs and without exogenous soluble factors that enabled cardiomyocyte differentiation of a murine induced PSC line based on controlled nutrient deprivation in 2D monolayer cultures. We showed that this protocol reproducibly imposed metabolic stress and consequently modulated active β-catenin levels to yield functional cardiomyocytes. The yield of cardiomyocytes and calcium handling kinetics were comparable to existing approaches. However, this approach did not produce consistent results between murine PSC lines suggesting signaling pathways linking nutrient deprivation to β-catenin activation are not universally conserved and may be a remnant of the parent population from which the induced PSCs were derived.