Neuregulin/ErbB Signaling Regulates Cardiac Subtype Specification in Differentiating Human Embryonic Stem Cells

Rationale:Human embryonic stem cell–derived cardiomyocytes (hESC-CMs) exhibit either a “working” chamber or a nodal-like phenotype. To generate optimal hESC-CM preparations for eventual clinical application in cell-based therapies, we will need to control their differentiation into these specialized cardiac subtypes. Objective:To demonstrate intact neuregulin (NRG)-1β/ErbB signaling in hESC-CMs and test the hypothesis that this signaling pathway regulates cardiac subtype abundance in hESC-CM cultures. Methods and Results:All experiments used hESC-CM cultures generated using our recently reported directed differentiation protocol. To support subsequent action potential phenotyping approaches and provide a higher-throughput method of determining cardiac subtype, we first developed and validated a novel genetic label that identifies nodal-type hESC-CMs. Next, control hESC-CM preparations were compared to those differentiated in the presence of exogenous NRG-1β, an anti–NRG-1β neutralizing antibody, or the Er...