Fig. 2.

Macrophage MR deficiency affects the transcriptome of fibroblasts in the aging heart. A Gating strategy to identify CD31⁻/TER119⁻/CD45⁻/CD11b⁻/NG2⁻/MEFSK4⁺/PDGFRα⁺ cells. Fibroblasts were isolated by flow cytometry from hearts of male/female young and old MR^flox and MR^LysMcre mice. B MA plots of gene expression in fibroblasts. Significantly differentially expressed genes (old vs. young) with adjusted p values < 0.1 are indicated in blue. C Graphical dot plot representation of the most significantly enriched pathways in fibroblasts. Comparison of altered pathways (p < 0.01) between MR^flox (WT) and MR^LysMCre (KO) mice determined by R package clusterProfiler. Large gene ratio in combination with high count and low p value indicates a more pronounced activation or inhibition for a specific pathway; D GSEA plot of downregulated ECM–receptor interaction pathway in fibroblasts from MR^LysMCre mice. E Volcano plot of contrast of old cardiac fibroblasts from MR^LysMcre vs. MR^flox mice. F Relative expression of Zbtb16 in young/old fibroblasts from MR^flox and MR^LysMCre hearts. Depicted points in red/black indicate, respectively, male and female mice. G Immunofluorescence micrographs of heart sections from old MR^flox and MR^LysMCre mice showing fibroblasts (PDGFRα⁺ cells) and ZBTB16 immunoreactivity. MR^LysMCre hearts displayed a weak expression of ZBTB16 in PDGFRα-positive fibroblasts. Nuclei were stained with NucBlue™. Mean ± SEM, n = 4–6 per group; *p < 0.05