The level and distribution of methyl-esters influence the impact of pectin on intestinal T cells, microbiota, and Ahr activation
Martin Beukema, Éva Jermendi, Marjolein M. P. Oerlemans, Madelon J. Logtenberg, Renate Akkerman, R. An, M. A. Berg, Erwin G. Zoetendal, Thijs Koster, Chunli Kong, Marijke M. Faas, Henk A. Schols, Paul de Vos
Abstract
Pectins are dietary fibres that modulate T cell immunity, microbiota composition, and fermentation profiles, but how this is influenced by the degree of methyl-esterification (DM) and degree-of-blockiness (DB) of pectin is unknown. Here, we demonstrate that supplementation of DM19(high-DB), DM49(low-DB) and DM43(high-DB) pectins at a low dose increased the frequencies of intestinal T-helper (Th)1 and Th2 cells after 1 week of pectin supplementation in mice, whereas DM18(low-DB) did not. After 4 weeks of supplementation with those pectins, Th1 and Th2 frequencies returned to control levels, whereas Rorγt+ regulatory T-cell frequencies increased. These structure-dependent effects could derive from induced shifts in microbiota composition that differed between DM18(low-DB) pectin and the other pectins. T-cell-modulating effects were not short-chain-fatty acid-dependent, but rather through an increase in Aryl-hydrocarbon-receptor-activating components. Thus, pectins with a specific combination of DM and DB have an impact on intestinal T cell-immunity in mice, when supplemented at a low dose.