Fig. 5: Tracing the fate of peri-TEB fibroblasts.
From: Contractile fibroblasts form a transient niche for the branching mammary epithelium
a Projections of z-stack imaging of whole mammary glands after tamoxifen induction (24 h and 3 weeks chase). White arrowheads indicate GFP+ fibroblasts, orange arrowheads indicate GFP+ adipocytes (expressing perilipin 1, PLIN1), empty arrowheads indicate GFP+ mural cells. White boxes outline areas (fibroblasts and adipocytes) shown in detail. Scale bars: 100 µm in (a), 20 µm in detail. b Quantification of GFP+ adipocytes and fibroblasts after 24 h or 3 weeks of chase; n = 4 mice per time-point, N = 38 z-stack for the 24 h chase—duct (0.123 mm3 in total), 19 z-stacks for 24 h chase—TEB (0.127 mm3 in total), 47 z-stacks for the 3 weeks chase (0.152 mm3 in total), statistical analysis: Student’s t-test, two-sided. c, d In vitro 3D adipogenesis assay on sorted (GFP+ and GFPneg) fibroblasts from Acta2-CreERT2;R26-mTmG mice after 24 h, 3 weeks or 6 weeks of chase. c Schematic outline of the experiment and representative images showing the morphology of sorted GFP+ and GFPneg fibroblasts after the indicated chase times. Cyan shows the lipid dye or GFP in the upper row (GFP+), while tdTomato (in red) delineates the membrane of GFPneg cells in the lower row. Scale bars: 20 µm. d Quantification of GFP+ fibroblast differentiation towards adipocytes; n = 3 independent experiments for 24 h and 3 weeks, and 2 for 6 weeks, statistical analysis: Fisher’s exact test.
