Abstract 312: Molecular Characterization and Prospective Isolation of Human Secondary Heart Field Progenitors From Pluripotent Stem Cells

The secondary heart field (SHF) progenitors ultimately contributes to diverse cardiovascular cell types through the formation of an early, multipotent heart progenitor pool and are marked by expression of ISL1, a LIM-homeodomain transcription factor. Human SHF can be derived from human pluripotent stem cells but their characterization has been limited due to the inefficiency of the differentiation protocols and lack of a proper reporter or surface marker based purification system. Using genetic tools and antibiotic selection we were able to purify ISL1+ cells for global gene expression analysis to identify key pathways that SHF identity. Genetic and small molecule based manipulation of these pathways alter ISL1 induction in differentiating cultures. Further proteomic analysis of enriched ISL1+ cells identified a hit surface marker that enables prospective isolation of ISL1+ secondary heart field progenitor cells with more than 90% purity. Purified SHF cells were multipotent and differentiate into pacemaker cells, endothelial and smooth muscle cells as well as mature beating cardiomyocytes. Finally transplantation of hPSC-derived purified SHF progenitors using this surface marker, restored myocardial function and regenerated infarcted area in mice myocardial infarction model.