Fig. 3: Vascular, stromal and mesothelial cells.

a, UMAP embedding of 17 vascular and mesothelial populations. EC1/2/3_cap, capillary ECs; EC4_immune, immune-related ECs; EC5_art, arterial ECs; EC6_ven, venous ECs; EC7_atrial, atria-enriched ECs; EC8_ln, lymphatic ECs; EC9_FB-like, ECs with FB features; EC10_CM-like, ECs with cardiomyocyte features; PC1_vent, ventricle-enriched pericytes; PC2_atrial, atria-enriched pericytes; PC3_str, stromal pericytes; PC4_CM-like, pericytes with cardiomyocyte features; SMC1_basic, basic SMCs; SMC2_art, arterial SMCs. b, Schematic of the vascular cells and their placement in the vasculature. c, Multiplexed smFISH of MYH11 (yellow) in SMC (thick in artery and very thin in small vein), CDH5 (red) in the endothelium, and SEMA3G (cyan) and ACKR1 (green) in EC5_art and EC6_ven, respectively in apex. Nuclei are counterstained with DAPI (dark blue). Scale bar, 20 μm. d, Predicted cell–cell interactions in arteries and veins. Data are available in Supplementary Table 10. e, f, Multiplexed smFISH of pan-FB DCN (cyan) and FAP (red) in FB4 in interventricular septum (SP) (e) and DCN (cyan) and LINC001133 (red) in FB5 in the apex (AX) (f). Nuclei are counterstained with DAPI (dark blue). Scale bars, 5 μm. g, UMAP embedding showing six FB populations and their respective marker genes. h, Multiplexed smFISH of C1QA⁺ macrophages (MP) and PTX3⁺ FB3, suggesting cross-talk between both cell types. Scale bar, 5 μm. For details on statistics and reproducibility, see Methods.