Dietary fiber pectin directly blocks toll-like receptor 2-1 and prevents doxorubicin-induced ileitis

Neha M. Sahasrabudhe*, Martin Beukema, Lingmin Tian, Berit Troost, Jan Scholte, Erik Bruininx, Geert Bruggeman, Marco van den Berg, Anton Scheurink, Henk A. Schols, Marijke M. Faas, Paul de Vos

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

135 Citations (Scopus)
525 Downloads (Pure)

Abstract

Dietary carbohydrate fibers are known to prevent immunological diseases common in Western countries such as allergy and asthma but the underlying mechanisms are largely unknown. Until now beneficial effects of dietary fibers are mainly attributed to fermentation products of the fibers such as anti-inflammatory short-chain fatty acids (SCFAs). Here, we found and present a new mechanism by which dietary fibers can be anti-inflammatory: a commonly consumed fiber, pectin, blocks innate immune receptors. We show that pectin binds and inhibits, toll-like receptor 2 (TLR2) and specifically inhibits the proinflammatory TLR2-TLR1 pathway while the tolerogenic TLR2-TLR6 pathway remains unaltered. This effect is most pronounced with pectins having a low degree of methyl esterification (DM). Low-DM pectin interacts with TLR2 through electrostatic forces between non-esterified galacturonic acids on the pectin and positive charges on the TLR2 ectodomain, as confirmed by testing pectin binding on mutated TLR2. The anti-inflammatory effect of low-DM pectins was first studied in human dendritic cells and mouse macrophages in vitro and was subsequently tested in vivo in TLR2-dependent ileitis in a mouse model. In these mice, ileitis was prevented by pectin administration. Protective effects were shown to be TLR2-TLR1 dependent and independent of the SCFAs produced by the gut microbiota. These data suggest that low-DM pectins as a source of dietary fiber can reduce inflammation through direct interaction with TLR2-TLR1 receptors.

Original languageEnglish
Article number383
Number of pages19
JournalFrontiers in Immunology
Volume9
DOIs
Publication statusPublished - 1-Mar-2018

Keywords

  • dietary fiber
  • toll-like receptor 2
  • pectin
  • ileitis
  • degree of methyl esterification
  • DENDRITIC CELLS
  • DIACYLATED LIPOPEPTIDES
  • DECTIN-1 ACTIVATION
  • BARRIER FUNCTION
  • CITRUS PECTIN
  • MOUSE MODEL
  • RECOGNITION
  • INFLAMMATION
  • METABOLITES
  • MICROBIOTA

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