Fig. 7: Rescue of HF defects in Mcl‑1‑deficient mice by concomitant loss of Bim or Bak.
From: MCL‑1 safeguards activated hair follicle stem cells to enable adult hair regeneration
A Schematics of experimental strategies to assess whether deletion of Bim or Bak rescues HF defects in the inducible K5‑CreER/Mcl‑1f/f (left panel) and constitutive K5‑Cre/Mcl‑1f/f (right panel) models. K5‑CreER/Mcl‑1f/f mice with deletion of single or both alleles of Bim or Bak at p55 were administered with tamoxifen containing diet to induce Mcl‑1 deletion, followed by depilation. Skin samples were harvested at 9 dpd for analysis. K5‑Cre/Mcl‑1f/f mice with single or both Bak alleles deleted were generated and analyzed. B, C Bim deletion partially rescues HF regeneration defects in K5‑CreER/Mcl‑1f/f mice. Representative H&E‑stained sections of dorsal skins harvested at 9 dpd. n = 6–8 mice per genotype. Scale bars, 100 µm (B). qPCR analysis of Bim expression in FACS sorted subpopulations. Data are mean ± SEM from 3 mice per genotype (C). D, E Bak deletion completely rescues HF regeneration defects in K5‑CreER/Mcl‑1f/f mice. Representative H&E‑stained histological sections of dorsal skins harvested at 9 dpd. n = 7–9 mice per genotype. Scale bars, 100 µm (D). qPCR analysis of Bak expression in FACS sorted subpopulations. Data are mean ± SEM from 3 mice per genotype (E). F Representative images of K5‑Cre/Mcl‑1f/f/Bak+/+, K5‑Cre/Mcl‑1f/f/Bak+/– and K5‑Cre/Mcl‑1f/f/Bak–/– mice at p90. n = 7–8 mice per genotype. Representative H&E‑stained sections and confocal images of dorsal skins harvested at p90. Scale bars, 100 µm (H&E), 50 µm (confocal). Basal layer stained by KRT14, hair matrix stained by PCAD and DAPI as nucleus counterstain. G, H FACS analysis of CD34 and SCA‑1 expression in epithelial cells from mice of indicated genotypes at p90 (G). Bar graph shows percentage of each subpopulation in CD49f+ epithelium (H). Data are mean ± SEM, n = 3–5 per genotype. *p < 0.05; **p < 0.01; n.s., non‑significant; Student’s t‑test. I, J In vitro clonogenic assay of CD34+ HF stem cells from mice of indicated genotypes at p21, grown on 3T3 feeder cells for 14 days. J Colony counts for each genotype, mean ± SEM for n = 3 independent experiments. **p < 0.01; Student’s t‑test.
