Fig. 1.

Desmoglein-2 (DSG2) and desmocollin-2 (DSC2) are reduced and mislocalized, and accompanied by altered morphology of desmosomes in the colonic tissue of tamoxifen-induced female Villin-CreER^T2;Klf5^fl/fl (Klf5^ΔIND) mice compared with the corn oil-injected control group, and Villin-CreER^T2 mice. A: qPCR analysis of Krüppel-like factor 5 (Klf5) mRNA expression levels was determined in corn oil-injected or tamoxifen-injected female Villin-CreER^T2 and Klf5^ΔIND mice, respectively. Data represent means ± SE (n = 8), *P < 0.05 and ***P < 0.001 by Student’s t-test. B: fluorescein isothiocyanate (FITC)-dextran concentrations in serum 4 h after gavage of 1mg FITC-4 kDa dextran solution. Data represent means ± SE (n = 8), *P < 0.05 by Student’s t-test. C: qPCR analysis of Cdh1, Ctnna1, Ctnnb1, Tjp1, Ocln, F11r, Cldn2, Cldn4, Dsg2, and Dsc2 mRNA expression levels was performed on tissues from corn oil-injected and tamoxifen-injected female Villin-CreER^T2 or Klf5^ΔIND mice. Data represent means ± SE (n = 8), **P < 0.01 by Student’s t-test. D: immunofluorescence staining of KLF5 (red) and DSG2 (green) (a–h), and KLF5 (green) and DSC2 (red) (i–p) in proximal colon and distal colon of corn oil-injected and tamoxifen-injected Villin-CreER^T2 and Klf5^ΔIND mice, respectively. DNA was counterstained with Hoechst dye. Images were taken at ×200 magnification. Scale bars in proximal sections indicate 20 µm, whereas scale bars in distal sections indicate 50 µm. Yellow arrowheads indicate DSG2 or DSC2 staining on basolateral membranes on the epithelial surface, whereas white arrowheads indicate DSG2 or DSC2 staining on the apical sides of the basolateral membranes in crypts. Relative mean fluorescence intensity was quantified (q and r). Data represent means ± SE (n = 10), *P < 0.05, **P < 0.01, and ***P < 0.001 by Student’s t-test. E: transmission electron microscopy images showing changes in morphology of desmosomes in Klf5-depleted colonic tissue (d, ×30,000 magnification) compared with the controls (a–c, ×30,000 magnification). White arrows indicate apical junctional complexes; yellow arrowheads indicate desmosomes. Scale bars indicate 400 nm. F: quantitative analysis of the number of desmosomes in colonic cells of corn oil- or tamoxifen-injected Villin-CreER^T2 and Klf5^ΔIND mice. Data represent means ± SE (n = 6 for corn oil-injected Villin-CreER^T2, n = 5 for tamoxifen-injected Villin-CreER^T2, and n = 8 for Klf5^ΔIND), ***P < 0.001, Student’s t-test. G: quantitative analysis of the width of the intercellular spaces between desmosomes in colonic cells of corn oil- or tamoxifen-injected Villin-CreER^T2 and Klf5^ΔIND mice. Data represent means ± SE (n = 37 for corn oil-injected Villin-CreER^T2, n = 29 for tamoxifen-injected Villin-CreER^T2, n = 42 for corn oil-injected Klf5^ΔIND, and n = 15 for tamoxifen-injected Klf5^ΔIND), **P < 0.01, Student’s t-test.