Fig. 2.

Intestinal epithelial VDR-specific knockout reduced mucus thickness, enhanced bacterial penetration, and reduced Claudin-10 expression in the VDR^ΔIEC mice. (A) Colonic mucus thickness declined in the VDR^ΔIEC mice, compared to the VDR^Loxp mice. Representative images of FISH staining of the colon of VDR^Loxp and VDR^ΔIEC mice, using the universal bacterial DNA probe EUB338-Alexa Fluor 488 [40], and nuclear staining DAPI (blue). The space between apical membranes of the epithelial cells and gut microbiome was indicated by dashed red lines. Images are from a single experiment and are representative of 4 mice per group. Three points were randomly selected for each mouse (data are expressed as mean ± SD. n = 12, Welch's t test). (B) Colonic mucus thickness was not changed in the O-VDR mice, compared to O-VDR^Loxp mice. Images are from a single experiment and are representative of 4 mice per group. (C) Mucus thickness declined in the colon of VDR^ΔIEC mice compared to VDR^Loxp mice. Representative images of Alcian Blue/PAS staining of the colon of VDR^Loxp and VDR^ΔIEC mice. The space between apical membranes of the epithelial cells and gut microbiome was indicated by dashed red lines. Images are from a single experiment and are representative of 4 mice per group. Three points were randomly selected for each mouse (data are expressed as mean ± SD. n = 12, Welch's t test). (D) Reduced Goblet cells in the colon of VDR^ΔIEC mice, compared to VDR^Loxp mice. Images are from a single experiment and are representative of 4 mice per group. Three points were randomly selected for each mouse (data are expressed as mean ± SD. n = 12, Welch's t test). (E) Enhanced bacteria in the tumors of the VDR^ΔIEC mice, as indicated in FISH staining. Images are from a single experiment and are representative of 6 mice per group (data are expressed as mean ± SD. n= 6, one-way ANOVA test) [41]. Claudin-10 was decreased in VDR^ΔIEC mice, compared to the VDR^Loxp mice at the basal level. Claudin-10 was further decreased in tumors of the VDR^ΔIEC mice by immunofluorescence staining. Images are from a single experiment and are representative of 6 mice per group (data are expressed as mean ± SD. n=6, one-way ANOVA test). (G) Claudin-10 was decreased in VDR^ΔIEC mice compared to VDR^loxp mice at the basal level and also in tumors by Western blots. (data are expressed as mean ± SD. n=3, one-way ANOVA test). All p values are shown in the figure.