Figure 5
From: Subversion of human intestinal mucosa innate immunity by a Crohn’s disease-associated E. coli
AIEC LF82 activates NFκB in human normal colonic crypts and is associated with IκBα phosphorylation. Human normal colonic mucosa explant cultures were treated or not for 4 h with LF82 (109 bacteria per explant), or with the commensal E. coli strain MG1655. (a) Immunoperoxidase staining with an antibody directed to NFκB p65 subunit. LF82 (middle), but not MG1655 (right), elicits a cytoplasmic-to-nuclear translocation of NFκB p65 (arrowheads) in the crypt epithelial cells. The histogram indicates the percentage of NFκB p65-positive nuclei in crypt epithelial cells of LF82-infected explant cultures compared with control untreated cultures, or with MG1655-infected explant cultures. Mean±s.e.m. of four experiments. (b) Immunoblot analysis of phospho-IκBα (ser 32–36) in explant cultures treated or not for 1 h with LF82 (109 bacteria per explant), with or without pretreatment with the proteasome inhibitor ALLN (100 μg ml−1 for 40 min). Equal protein load was evaluated by β-actin. Representative of three independent experiments.
