The dietary fibre rhamnogalacturonan improves intestinal epithelial barrier function in a microbiota-independent manner

© 2021 The British Pharmacological Society..

BACKGROUND AND PURPOSE: Dietary fibre comprises a complex group of polysaccharides that are indigestible but are fermented by gut microbiota, promoting beneficial effects to the intestinal mucosa indirectly through the production of short chain fatty acids. We found that a polysaccharide, rhamnogalacturonan (RGal), from the plant Acmella oleracea, has direct effects on intestinal epithelial barrier function. Our objective was to determine the mechanism whereby RGal enhances epithelial barrier function.

EXPERIMENTAL APPROACH: Monolayers of colonic epithelial cell lines (Caco-2, T84) and of human primary cells from organoids were mounted in Ussing chambers to assess barrier function. The cellular mechanism of RGal effects on barrier function was determined using inhibitors of TLR-4 and PKC isoforms.

KEY RESULTS: Apically applied RGal (1000 μg ml-1 ) significantly enhanced barrier function as shown by increased transepithelial electrical resistance (TER) and reduced fluorescein isothiocyanate (FITC)-dextran flux in Caco-2, T84 and human primary cell monolayers, and accelerated tight junction reassembly in Caco-2 cells in a calcium switch assay. RGal also reversed the barrier-damaging effects of inflammatory cytokines on FITC-dextran flux and preserved the tight junction distribution of occludin. RGal activated TLR4 in TLR4-expressing HEK reporter cells, an effect that was inhibited by the TLR4 inhibitor, C34. The effect of RGal was also dependent on PKC, specifically the isoforms PKCδ and PKCζ.

CONCLUSION AND IMPLICATIONS: RGal enhances intestinal epithelial barrier function through activation of TLR4 and PKC signalling pathways. Elucidation of RGal mechanisms of action could lead to new, dietary approaches to enhance mucosal healing in inflammatory bowel diseases.

Medienart:

E-Artikel

Erscheinungsjahr:

2022

Erschienen:

2022

Enthalten in:

Zur Gesamtaufnahme - volume:179

Enthalten in:

British journal of pharmacology - 179(2022), 2 vom: 16. Jan., Seite 337-352

Sprache:

Englisch

Beteiligte Personen:

Baggio, Cristiane H [VerfasserIn]
Shang, Judie [VerfasserIn]
Gordon, Marilyn H [VerfasserIn]
Stephens, Matthew [VerfasserIn]
von der Weid, Pierre Yves [VerfasserIn]
Nascimento, Adamara M [VerfasserIn]
Román, Yony [VerfasserIn]
Cipriani, Thales R [VerfasserIn]
MacNaughton, Wallace K [VerfasserIn]

Links:

Volltext

Themen:

Colonoid monolayer
Dietary Fiber
Epithelial barrier
Intestinal permeability
Journal Article
Polysaccharide
Research Support, Non-U.S. Gov't
Rhamnogalacturonans
TLR4
Toll-Like Receptor 4

Anmerkungen:

Date Completed 13.04.2022

Date Revised 31.05.2022

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1111/bph.15739

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM333223411