Fig. 4: Transcriptome comparison between the VELs and the primary VECs.

a KEGG analysis of the shared genes between the VELs and the primary VECs, showing the enrichment of TGF-β, WNT, BMP, and NOTCH signaling pathways. b Heat map analysis showing that the majority of top 100 genes were highly expressed in the primary VECs and hPSC-derived VELs, but lowly in HAEC/HUVEC. c Validation of the indicated genes by qRT-PCR analysis. d WB results showing that BMP4 was expressed at much higher levels in day 7 hPSC-derived VELs than HUVEC. e IF staining results showing that the indicated markers were expressed at higher levels in day 7 hPSC-derived VELs than in HUVEC. Scale bar: 100 μm. f The t-SNE map showing the second-level clustering of VECs into two subpopulations, designated as 0 and 1. g Violin plots showing the expression of indicated genes for subcluster 0 and 1, suggesting that subcluster 0 may represent ventricular side specific VECs and subcluster 1 may represent aortic side specific VECs. h tSNE maps showing that the indicated marker genes were indeed highly expressed in the VEC subclusters. i qRT-PCR results showing that the indicated genes were expressed much higher in VECs than HAEC and HUVEC. VEC-A and VEC-V represent the aortic and the ventricular side of VECs, respectively. The paired t test in Graphpad software was used for the statistical analysis. Significant levels are: *p < 0.05; **P < 0.01; ***P < 0.001.