Citrobacter rodentium Infection Inhibits Colonic P-glycoprotein Expression.

P-glycoprotein (Pgp/MDR1) serves as a biological barrier that protects intestinal epithelial cells (IECs) by transporting out xenobiotics and bacterial toxins. Decreased Pgp function and expression has been seen in mouse models of inflammatory colitis and also in patients with IBD. Pgp knockout mice spontaneously develop severe colitis, which is also seen in human patients with ulcerative colitis. However, whether Pgp is also altered in infectious colitis is not known. Citrobacter rodentium (CR), a murine pathogen has been shown to cause colonic hyperplasia and colitis in mice by attaching to IECs. The current study investigated the direct effects of Citrobacter rodentium infection on intestinal Pgp expression in mice. Mice were challenged with a single dose of C. rodentium (1 × 109 CFU) by oral gavage for 9 days and Pgp expression in the ileum and colon was measured by real time qRT-PCR and immunofluorescence studies. Our results showed that C. rodentium infection significantly decreased Pgp mRNA and protein expression in the colon, although no significant change was observed in the ileum of mice. These findings suggest that inhibition of the efflux protein, Pgp by C. rodentium can cause perturbations in the intestinal epithelial integrity, which could further lead to the pathogenesis of intestinal inflammation as observed in infectious colitis.