Fig 1: Krt14+Ctsk+ cells in hSM.a Representative H&E staining image of hSM (left) and confocal images of hSM under homeostatic condition (right). Merged and single-channel images of Ctsk (red), Krt14 (green), and Vim (blue) are shown in each panel. n = 3 from 3 different experiments; area in the white dotted box is magnified on the right; scale bar, 50 µm. b Illustration showing the strategy for Krt14+Ctsk+ cell labeling in hSM by LV-Krt14pro-tdTomato + LV-Ctskpro-EGFP, and for tdT+EGFP+ (representing Krt14+Ctsk+ cells), tdT+EGFP– (representing Krt14+Ctsk– cells) and tdT–EGFP+ (representing Krt14–Ctsk+ cells) cell sorting by FASC after 72 h of infection. c Proportion of FACS-sorted cells. d Histogram generated from c. Data are presented by means ± SD; n = 3. e Representative ARS images showing osteogenic differentiation capacities of Krt14+Ctsk+ cells cultured in OM versus Krt14+Ctsk+ cells in OM + TGF-ß1 versus Krt14–Ctsk+ cells in OM after 4 weeks. f Representative confocal images of human Krt14+Ctsk+ cells cultured in OM at different time points. Merged and single-channel images of Ctsk (green), Krt14 (blue), Cdh1 (gray) and Alpl (red) are shown in each panel. Scale bar, 25 µm. n = 3 from 3 independent experiments. g Correlation analysis of Krt14+Ctsk+ cells from hSM and mNM at transcriptomic level. TPM reads of genes were analyzed by Spearman correlation analysis. R = 0.78, P < 2.2e–16. h–j Comparison of TPM of epithelial (h), mesenchymal (i) and osteogenic (j) specific markers in Krt14+Ctsk+ cells from hSM and mNM. Error bars indicate SEM.