Fig. 3: Intestinal epithelial cells in the Pex2^−/− small intestines show defects in desmosome distribution and reduction in cell size.

A IF image of Desmoplakin (Dsp) in small intestine cryosections. n = 40 sections derived from four mice per genotype Scalebar = 20 µm. B The bar graph reports the values of MFI per image in WT and Pex2^−/− cryosections. C Desmoplakin puncta distribution is shown as a density plot histogram of the average distance measured in Imaris between the five nearest neighbors. The density plot histogram was created in R, and a Two-sample Kolmogorov-Smirnov test was run: p-value < 2.2e-¹⁶. D Imaging of Desmoplakin in WT and Pex2^−/−MIO-derived monolayers. n = 40 monolayers derived from four mice per genotype Scalebar = 20 µm. E The average distance between the three nearest neighbors measured in Imaris was reported in a relative density plot histogram. Statistical significance was determined in a two-sample Kolmogorov-Smirnov test: p-value = 1.439e^-05. F TEM imaging of small intestine sections from small intestines at day 0 pups, with desmosomes highlighted by the white arrows. Scalebar = 1 µm, 10,000X magnification. The length and thickness of desmosomes were manually measured in ImageJ, n = 3 from three mice per genotype. G Detection of E-cadherin in WT and Pex2^−/− MIO. Scalebar = 10 µm. The bar graph represents the cell size reported in μm². n = 40 from four mice per genotype. H Imaging of E-cadherin in MIO-derived monolayers. n = 30 monolayers derived from three mice per genotype. Scalebar = 20 µm. The bar graph represents the average cell area reported in μm². I Detection of Armadillo (Arm) in Drosophila intestines dissected from Mex > w¹¹¹⁸, Mex > Pex5-i and Mex > Pex5-i; Pex5. n = 10 guts from 10 flies per genotype. The dotted lines in the right panels are enterocyte boundary traces of the above panels to illustrate enterocyte size. Scalebar = 10 µm. The bar graph represents the average cell area reported in μm². J The bar graph represents the quantification of fluorescence intensity of FITC-dextran in permeability assays of MIO-derived monolayers; n = 5 monolayers. K Representative picture of the Smurf assay on 20-day-old female flies. The dotted lines in the right panels are enterocyte boundary traces of the above panels to illustrate enterocyte size. The bar graph indicates the percentage of dark blue area divided by the total abdomen area; scale bar = 500 µm, n = 20 flies per genotype and condition. In all the bar graphs, the error bars represent the standard deviation. Significance was determined using one-way ANOVA in I and K and Student’s t-test for all the other graphs. ****p < 0.0001; **p < 0.01; *p < 0.05; ns not significant.