Fig. 4

MiR-31 induces mammary basal stem cell expansion. a Flow cytometry profiles of CD24-PE-Cy7 and CD29-FITC in cell suspensions from TRE-miR31 (n = 4), K5-rtTA (n = 4) and DTG (n = 4) mammary glands at the same proestrus phase. Arrows indicate the CD24⁺CD29^high population. b Quantification of CD24⁺CD29^high cell populations in control (TRE-miR31 or K5-rtTA, n = 4) and DTG (n = 4) mice. c Flow cytometry profiles of CD24-PE-Cy7 and CD29-FITC in cell suspensions from Control (n = 3) and miR-31 KO (n = 3) mammary glands at the same proestrus phase at 12 weeks of age. Arrows indicate the CD24⁺CD29^high population. Quantification of CD24⁺CD29^high cells is shown to the right. d Flow cytometry profiles of CD24-PE-Cy7 and CD29-FITC in cell suspensions from K14-Cre and K14-Cre;miR-31^fl/fl mammary glands at the same proestrus phase at 10 weeks of age. Arrows indicate the CD24⁺CD29^high population. e GFP profiles of mammary epithelial cells from Lgr5-eGFP-CreER (Control, n = 3) and Lgr5-eGFP-CreER;miR-31 KO (miR-31 KO, n = 3) mice. Quantification of Lgr5-GFP⁺ cells in control and miR-31 KO mice. f Numbers of colonies formed by Control (scramble RNA), Dox, anti-miR-31 and Dkk1 treated DTG mammary epithelial cells over six passages. n = 4 independent experiments. g Limiting dilution transplantation results. Top panel shows a representative whole mount analysis of repopulated mammary glands regenerated from 500 and 1000 CD24⁺CD29^high MaSC cells from Control and miR-31 KO mice 7 weeks after transplantation. Bottom Table summarizes the transplantation results from 100 (n = 6), 500 (n = 5) and 1000 (n = 4) CD24⁺CD29^high MaSC cells. Data represented as mean ± S.D. n ≥ 3. Two tailed unpaired t-test for b, c, e (*P < 0.05; **P < 0.01)