Pectin limits epithelial barrier disruption byCitrobacter rodentiumthrough anti-microbial effects

Abstract

Scope:C. rodentiumis the murine equivalent of EnteropathogenicEscherichia. coli(EPEC) and EnterohemorrhagicEscherichia coli(EHEC) which induce damage to the intestinal epithelial barrier that results in diarrhea and intestinal inflammation. Dietary fibre intake can be an effective approach to limit epithelial damage by these enteric pathogens. Therefore, the protective effect of dietary fibre pectin against dysfunction of epithelial barrier integrity uponC. rodentiuminfection was investigated.Methods and results: Pectins that structurally differed in the degree and distribution of methylesters were tested on barrier protective effects on epithelial cells againstC. rodentiumby measuring transepithelial electrical resistance and lucifer yellow fluxes. All three pectins protected the epithelial barrier fromC. rodentiuminduced damage in a structure-independent manner. These barrier protective effects were also independent of pectin-induced TLR2 activation. Furthermore, the pectins induced anti-adhesive effects onC. rodentiumby interacting withC. rodentiumand not with epithelial cells. This may be explained by antimicrobial effects of pectins onC. rodentiumand not on other enteric bacteria includingLactobacillus plantarumandE. coli. A competition ELISA for binding ofC. rodentiumto pectin supported this finding as it showed that pectin interacts strongly withC. rodentium, whereas it interacts weakly or not withL. plantarumorE. coli.Conclusion: These findings demonstrate that pectin protects the epithelial barrier fromC. rodentiuminduced damage by inducing anti-microbial effects.