Fig. 4: BMP signaling coordinates with Wnt signaling to sustain Lgr5⁺ ISCs.

a Representative bright-field images of small intestinal organoids cultured for 7 days in 5 μM CHIR (C5), 10 μM CHIR (C10), 5 μM CHIR plus LDN (C5L) and 10 μM CHIR plus LDN (C10L). b, c Fluorescence images (b) and FACS analysis of GFP expression (c) of small intestinal organoids cultured with C10, C5 and C10L for 7 days. d, f Fluorescence images (d) and FACS analysis of GFP expression (e) of wild-type, Alk3^−/− or Smad4^−/− crypts cultured in the indicated conditions for 7 days. f Representative images and quantitation of colony numbers and sizes of Apc^−/− organoids cultured with or without BMP4. g EdU staining of proliferating cells in Apc^−/− organoids cultured with or without BMP4. h, i Fluorescence images (h) and FACS analysis of GFP expression (i) of Apc^−/− organoids with or without BMP4. j Gene expression change of Apc^−/− organoids after BMP4 treatment. Scale bars, 100 μm. ***P < 0.001, **P < 0.01, and *P < 0.05 analyzed by two-way ANOVA test in c and e and by Student’s t-test in f, i, and j. Error bars, s.d. n = 3 mice in c, n = 4 wells from 2 mice in e and i, n = 3 independent experiments in f and f, 50 organoids were calculated for their sizes in f