Pectins that Structurally Differ in the Distribution of Methyl-Esters Attenuate Citrobacter rodentium-Induced Colitis

SCOPE: Pectins have anti-inflammatory properties on intestinal immunity through direct interactions on Toll-like receptors (TLRs) in the small intestine or via stimulating microbiota-dependent effects in the large intestine. Both the degree of methyl-esterification (DM) and the distribution of methyl-esters (degree of blockiness; DB) of pectins contribute to this influence on immunity but whether and how the DB impacts immunity through microbiota-dependent effects in the large intestine is unknown. Therefore, we tested pectins that structurally differ in DB in a mouse model with Citrobacter rodentium-induced colitis and studied the impact on the intestinal microbiota composition and associated attenuation of inflammation.

METHODS AND RESULTS: Both low and high DB pectins induced a more rich and diverse microbiota composition. These pectins also lowered the bacterial load of C. rodentium in caecal digesta. Through these effects, both low and high DB pectins attenuated C. rodentium-induced colitis resulting in reduced intestinal damage, reduced numbers of Th1-cells which are increased in case of C. rodentium-induced colitis, and reduced levels of GATA3+ Tregs which are related to tissue inflammation.

CONCLUSION: Pectins prevent C. rodentium-induced colonic inflammation by lowering the C. rodentium load in the caecum independently of the DB. This article is protected by copyright. All rights reserved.