Fig. 3: Subtype switching of cardiac fibroblasts highly correlates with CM maturation.

a The expression of selected ligands potentially involved in CM maturation or housekeeping genes in FBs during maturation. b, c Immunofluorescent staining of VIM and FABP4 (b) or EGR1 (c) in neonatal (P1) or adult (P56) heart sections, respectively. White arrows indicate co-localization, purple arrows indicate VIM⁺ only cells. Scale bars = 10 or 4 μm. d, e Quantification of VIM⁺FABP4^High (d) or EGR1^High (e) cells in heart sections from P1 or P56 mice, Data are plotted as mean ± SEM, n = 5 biologically independent mice, ***p < 0.001, two-sided Student’s t-test. f, g Monocle analyses showing the ordering of FBs in pseudotime. Each color indicates either a time point (f) or a cell state (g). h Heatmap to display different blocks of top 1000 differentially expressed genes (DEGs) along the pseudotime trajectory (f, g). Please see Supplementary Data 17 for the full list. i Selected top gene ontology (GO) terms related to corresponding DEGs (Supplementary Data 18–20). Functional analysis was performed with enrichGO in clusterProfiler, p < 0.05 was considered significant enrichment. Source data are provided as a Source Data file.