A HCN4+ cardiomyogenic progenitor derived from the first heart field and human pluripotent stem cells

The mammalian heart is formed from two distinct groups of mesodermal cells, the first and second heart fields (FHF and SHF). Little is known about the progenitors giving rise to the FHF, but Chien and colleagues have now identified HCN4 (hyperpolarization-activated cyclic nucleotide-gated channel 4) as an FHF marker. They show by lineage tracing that cells expressing HCN4 primarily contribute to cardiomyogenic lineages, and use this marker to isolate FHF progenitors from differentiation cultures of human embryonic stem cells.