Stage-Specific Optimization of Activin/Nodal and BMP Signaling Promotes Cardiac Differentiation of Mouse and Human Pluripotent Stem Cell Lines

SummaryEfficient differentiation of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) to a variety of lineages requires step-wise approaches replicating the key commitment stages found during embryonic development. Here we show that expression of PdgfR-α segregates mouse ESC-derived Flk-1 mesoderm into Flk-1+PdgfR-α+ cardiac and Flk-1+PdgfR-α− hematopoietic subpopulations. By monitoring Flk-1 and PdgfR-α expression, we found that specification of cardiac mesoderm and cardiomyocytes is determined by remarkably small changes in levels of Activin/Nodal and BMP signaling. Translation to human ESCs and iPSCs revealed that the emergence of cardiac mesoderm could also be monitored by coexpression of KDR and PDGFR-α and that this process was similarly dependent on optimal levels of Activin/Nodal and BMP signaling. Importantly, we found that individual mouse and human pluripotent stem cell lines require optimization of these signaling pathways for efficient cardiac differentiation, illustrating a principle that may well apply in other contexts.

► Expression of Flk1/KDR and PDGFR-α identify PSC-derived cardiac mesoderm
► Cardiac specification requires stage-specific Activin/Nodal and BMP signaling
► Individual PSC lines require optimization for efficient cardiac differentiation