GSE196512
EPICARDIOID SINGLE-CELL GENOMICS UNCOVER PRINCIPLES OF HUMAN EPICARDIUM BIOLOGY IN HEART DEVELOPMENT AND DISEASE [scATAC-Seq]
Native human epicardial precursors are virtually inaccessible, as they appear in the embryo less than four weeks post-conception, at which point pregnancy may not yet be detected. Protocols have been established to generate epicardial cells and their progeny from human pluripotent stem cells in vitro. However, no current model is amenable to studying the many facets of human epicardial biology, notably epicardium formation, lineage heterogeneity, and functional crosstalk with other cardiac cell types during organ development and disease. Here, we generated human pluripotent stem cell-derived 3D heart organoids showing retinoic acid-dependent self-organization of the epicardium and myocardium, which we called epicardioids. Time course single-cell RNA sequencing revealed that epicardioids are formed through the specification of first heart field progenitors, a subset of which closely correspond to juxta-cardiac field (JCF) cells that have recently been identified in the embryonic mouse heart as novel common progenitors of myocardium and epicardium and have not yet been described and studied in humans. Analysis of chromatin accessibility by single-cell ATAC-seq additionally revealed key transcriptional programs guiding fate decisions along the epicardial lineage tree. Human epicardioids provide a unique model to gain fundamental insights into human epicardium biology and function during heart development, homeostasis, and disease. Overall design: single cell identification of accessible chromatin regions during timecourse differentiation (days 2,3,4,5,7,10,15) of hiPSC derived cardiac organoids (epicardioids)