Extended Data Fig. 2: Location of major fibroblast populations in the mouse intestine.

a, Detection of Pdgfra-expressing mesenchymal cells in the intestine of adult Pdgfra-H2B-eGPF-knockin mice⁴. Two distinct populations of Pdgfra^high and Pdgfra^low mesenchymal cells were detected in fixed tissue sections by direct eGFP fluorescence (green) and confocal microscopy. Nuclei are stained with DAPI (blue). Pdgfra^high cells are located under the epithelium along the crypt–villus axis and in the muscularis propria. They form clusters at the tips of villi and the apical part of the colonic mucosa. Pdgfra^low cells are located in the inner part of the villi, the pericryptal area and the submucosa. Filled arrows indicate pericryptal Pdgfra^low cells. Open arrows indicate subepithelial Pdgfra^high cells. M, mucosa; V, villus; SM, submucosa; MP, muscularis propria. Scale bars, 20 μm. Data are representative of six independent experiments. b, Detection of Pdgfra^high and Pdgfra^low fibroblasts in the fresh, intact intestine of adult Pdgfra-H2B-eGPF-knockin mice⁴ by two-photon microscopy. The cells were detected by direct eGFP fluorescence (green). Pdgfra^high cells are predominant in the muscularis propria, whereas Pdgfra^low cells are predominant in the submucosa. Both populations are present in the mucosa. Data are representative of independent observations from one experiment. Scale bars, 100 μm. c, Detection of Pdgfra^high and Pdgfra^low fibroblasts in the intestine of Pdgfra-H2B-eGPF-knockin embryos on embryonic day 15 (E15.0) and in early postnatal development. E15.0: clusters of Pdgfra^high cells in early villi are indicated by white arrows. Pdgfra^low mesenchymal cells occupy the rest of the mesenchyme (asterisks). P0: Pdgfra^high cells are observed in the villi (V) and Pdgfra^low cells are observed both in the villi and in the rest of the mesenchyme (asterisks). P15: Pdgfra^low cells surround an early crypt (C) and Pdgfra^high cells are located at the edges of the crypt (open white arrows). Pdgfra^low cells occupy the inner mesenchyme (asterisks). Data are representative of independent observations from one experiment per developmental stage. Scale bars, 20 μm. d, The location of Fgfr2-expressing mesenchymal cells was determined in the intestine of an Fgfr2-T2A-H2B-mCherry-knockin mouse⁵, by detecting direct mCherry fluorescence (red) in the nucleus (blue, DAPI). The arrows indicate pericryptal Fgfr2⁺ fibroblasts. Data are representative of independent observations from one experiment. Scale bars, 20 μm. e, Immunostaining for laminin A1 (encoded by Lama1), the epithelial marker E-cadherin and the mesenchymal marker vimentin in the normal mouse intestines shows that laminin A1 is detected specifically at the mesenchymal–epithelial interface. Data are representative of two independent experiments. Scale bars, 5 μm. f, In-situ hybridization analysis showing the location of Rspo1-expressing cells in the normal mouse colon. The position of Rspo1-expressing cells along the crypt axis was quantified in 40 × 80 μm² sub-epithelial areas at the base, middle and top sections of n = 9 crypts. Unpaired two-tailed Student’s t-test. Mean ± s.e.m. **P < 0.01.

Source Data