re 5a), a trend conditions inin untreated PAK6 Species animals (Figure5a), a trend that was

re 5a), a trend conditions inin untreated PAK6 Species animals (Figure5a), a trend that was also noticed for Claudin-2 exwas also observed for Claudin-2 pression (Figure 5d, p 0.05). Nevertheless, overall, in our in vivo the Selenof Selenof expression (Figure 5d, p 0.05). Even so, general, in our in vivo model,model, the genotype showed showed small to no effect on mRNA expression of tight junction proteins genotype tiny to no effect on mRNA expression of tight junction proteins Claudin-1 (Cldn-1), two (Cldn-2) and 15 (Cldn-15). Western blot analyses Western blot analyses claudin-2 PI4KIIIα custom synthesis overClaudin-1 (Cldn-1), two (Cldn-2) and 15 (Cldn-15). showed low expression ofshowed low all, and no visible variations in protein visible differences in protein expression for expression of claudin-2 all round, and no expression for Claudin-1 or Claudin-3 (Figure 5g) or Claudin-2 (Figure (Figure 5g) WT and KO (Figure 5h) among WT and KO mice. It Claudin-1 or Claudin-35h) in between or Claudin-2mice. It must be noted that mRNA expression be noted that mRNA expression of those tight junction genes in AOM/DSS-treated must of these tight junction genes in AOM/DSS-treated animals, interestingly, showed a positiveinterestingly, showed a positivewith significant impact on expression of with animals, correlation with dietary selenium, correlation with dietary selenium, Cldn-2 (p = 0.0016) and on expression of Cldn-2 (p = 0.0016) and Cldn-15 (p = 0.0008). considerable effect Cldn-15 (p = 0.0008). In addition to tight junction genes, we also evaluated the mRNA expression of genes commonly associated with adherens junctions along with other barrier integrity functions in control animals’ colon scrapes and in colon tumor tissues (Figure S8). Dietary selenium levels appeared to impact mRNA expression with the transmembrane glycoprotein epithelial cell adhesion molecule (EpCAM), Nectin cell adhesion molecule (Nectin)-2, membrane-associated carbonic anhydrase 4 (Car4), as well as the secreted glycoprotein mucin 2 (Muc2) in either WT or KO mice, or each. Interestingly, Selenof -genotype didn’t seem to substantially influence mRNA expression of the investigated genes in colons of mice, except for Epcam, which was drastically lower in tumors of Selenof-KO mice in comparison with WT mice, but only at higher selenium levels. Having said that, even though gene expression of tight junction and adherens junction genes were not substantially altered in between Selenof-KO mice and their WT littermates, the considerably increased size of goblet cells in KO mice recommend structural alterations relevant to colon tumorigenesis.Int. J. Mol. Sci. 2021, 22, 10651 Int. J. Mol. Sci. 2021, 221,10 of 19 10 ofFigure 5. Expression of tight junction Claudin genes. mRNA expression was measured with qPCR Figure five. Expression of tight junction Claudin genes. mRNA expression was measured with qPCR in (a,c,e) colon scrapes of handle mice and (b,d,f) colon tumors ofof AOM/DSS-treated mice. Imply in (a,c,e) colon scrapes of handle mice and (b,d,f) colon tumors AOM/DSS-treated mice. Imply (N = 4) + SEM, 2-way ANOVA, followed by Tukey’s post hoc analyses to evaluate KO vs. WT by diet program; (N = 4) + SEM, 2-way ANOVA, followed by Tukey’s post hoc analyses to evaluate KO vs. WT by diet plan; letters indicate statistically considerable variations. Protein expression of (g) Claudin-1 and Claudinletters indicate statistically considerable variations. Protein expression of (g) Claudin-1 and Claudin-3, 3, and (h) Claudin-2 in colon scrapes of manage mice on selenium-specific diets was asse