Fig. 3

Chromatin profiling of human cardiac LECs shows enriched binding motifs of ETS transcription factors (A) TF perturbations followed by expression (GO analysis) of the top 500 DEGs from LEC cluster predict an early ETV2 activation. (B) Volcano plot showing positive enrichment of motifs from LEC cluster 14. (C) FeaturePlots showing the motif enrichment for ETV2. (C′) Probability of Tn5 insertion across the genome centered around predicted ETV2 binding motif. The LEC cluster (cluster 14) and the macrophage cluster (group 19) have higher enrichment compared with the mesothelial cells (groups 7 and 23). (D) FeaturePlots illustrating RNA expression (top) from the WNN analysis of PROX1, NR2F2, SOX18, and RBPJ, and FeaturePlots showing the motif enrichment for PROX1, NR2F2, SOX18, and RBPJ (bottom). (E) Pseudobulk of the genome accessibility for the PROX1 locus for selected clusters from the multiome and the correlation coefficient between the accessibility of the peak and RNA expression of the gene showing positive correlation between the 5 kb enhancer and the promoter of the PROX1 gene. Red arrow: peak in cardiomyocytes; green arrow: peak in LECs and other PROX1+ ECs. (F) 12PCW fetal heart immunohistochemistry for MEF2 (red) and PROX1 co-staining (green) (n = 3); the magnified view shows co-staining of MEF2 and PROX1 in cardiomyocytes (white arrows) and PROX1 staining in epicardial LECs (arrowheads). Scale bars, 100 μm.