Fig. 3: OXGR1 on SMG progenitors drives their regeneration of the SAE.

a Representative images of DCLK1 and BCAM staining in tracheal sections from the indicated Sox9-tdT reporter strains at day 14. Sox9-tdT⁺BCAM⁺ cells (white arrow). Scale bars: 50 µm. b Quantification of Sox9-tdT⁺BCAM⁺ cells in the SAE from the indicated strains at day 14. Group sizes: n = 5, 6, 12, 5 mice, from left to right. Two-tailed unpaired Mann-Whitney U test. c, d Combined in situ hybridization (ISH) for Oxgr1, Krt5 and Krt8, and immunofluorescence for SOX9 and α-SMA in tracheal sections from WT mice with or without ALT treatment (Krt5 for BCs, Krt8 for differentiated cells, SOX9 for SMG progenitor cells, and α-SMA for SMG myoepithelial cells). Oxgr1⁺SOX9⁺ cells (green arrows). Scale bars: 20 μm. SMG Submucosal gland. (e) Quantification of Oxgr1⁺ cells in the specified EpC subsets. Group sizes: n = 7, 16, 8, 13, 6, 10, 7, 8 mice, from left to right. Kruskal–Wallis test followed by Dunn’s multiple-comparisons test with Holm–Bonferroni correction. f Quantification of Oxgr1⁺ cells among the Krt5⁺ or Krt8⁺ cells. Group sizes: n = 12, 11, 12, 7 mice, from left to right. Two-tailed unpaired Mann-Whitney U test. g Experimental schema. h, i Representative images (h) and quantification (i) of BCAM and SOX9 staining in tracheal sections from the indicated strains at day 14. Scale bars: 20 μm. Group sizes: n = 5, 8, 7, 5 mice, from left to right. Kruskal–Wallis test followed by Dunn’s multiple-comparisons test with Holm–Bonferroni correction. The dashed line marks the border between SAE and SM. Box plots (b, e, f, i) show median (center line), 25th–75th percentiles (box), and min–max values (whiskers). Each data point represents the average of 3–4 images from one mouse. See “Methods”. Panel g was created in BioRender. Lee, M. (https://BioRender.com/dg3i7rm). Source data are provided as a Source Data file.