title: Nondigestible oligosaccharides exert nonprebiotic effects on intestinal epithelial cells enhancing the immune response via activation of TLR4-NFκB.
abstract: METHODS
  Prebiotic effects of non absorbable glucids depend mainly on digestion by the colonic microbiota. Our aim was to assess nonprebiotic, direct effects of 4 prebiotics, namely fructooligosaccharides, inulin, galactooligosaccharides, and goat's milk oligosaccharides on intestinal epithelial cells.
  
  
  RESULTS
  Prebiotics were tested in intestinal epithelial cell 18 (IEC18), HT29, and Caco-2 cells. Cytokine secretion was measured by ELISA and modulated with pharmacological probes and gene silencing. Prebiotics induced the production of growth-related oncogene, (GROα), monocyte chemoattractant protein 1 (MCP-1), and macrophage inflammatory protein 2 (MIP2) in IEC18 cells, with an efficacy that was 50-80% that of LPS. Prebiotics did not change RANTES expression, which was robustly induced by LPS in IEC18 cells. Cytokine secretion was suppressed by Bay11-7082, an inhibitor of IκB-α phosphorylation. The response was markedly decreased by Myd88 or TLR4 gene knockdown. Prebiotics also elicited cytokine production in HT29 but not in Caco-2 cells, consistent with reduced and vestigial expression of TLR4 in these cell lines, respectively. Prebiotic-induced MCP-1 secretion was reduced also in colonic explants from TLR4 KO mice compared with the controls.
  
  
  CONCLUSIONS
  We conclude that prebiotics are TLR4 ligands in intestinal epithelial cells and that this may be a relevant mechanism for their in vivo effects.
authors.affiliation: Department of Biochemistry and Molecular Biology II, CIBERehd, School of Pharmacy, University of Granada, Granada, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Ortega-González
authors.forename: Borja
authors.initials: B
authors.lastname: Ocón
authors.forename: Isabel
authors.initials: I
authors.lastname: Romero-Calvo
authors.forename: Andrea
authors.initials: A
authors.lastname: Anzola
authors.forename: Emilia
authors.initials: E
authors.lastname: Guadix
authors.forename: Antonio
authors.initials: A
authors.lastname: Zarzuelo
authors.forename: Maria D
authors.initials: MD
authors.lastname: Suárez
authors.forename: Fermin
authors.initials: F
authors.lastname: Sánchez de Medina
authors.forename: Olga
authors.initials: O
authors.lastname: Martínez-Augustin
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D018932:Chemokine CCL2 / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects*; D005260:Female; D055785:Gene Knockdown Techniques; D019073:HT29 Cells; D006801:Humans; D007422:Intestines / Q000166:cytology* / Q000187:drug effects / Q000382:microbiology; D007444:Inulin / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000009:adverse effects; D008297:Male; D008810:Mice, Inbred C57BL; D064307:Microbiota; D053594:Myeloid Differentiation Factor 88 / Q000235:genetics / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D009844:Oligosaccharides / Q000494:pharmacology*; D056692:Prebiotics; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism*
chemical_list: C491768:Ccl2 protein, mouse; D018932:Chemokine CCL2; D008070:Lipopolysaccharides; C507780:Myd88 protein, mouse; D053594:Myeloid Differentiation Factor 88; D016328:NF-kappa B; D009844:Oligosaccharides; D056692:Prebiotics; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4; C116580:fructooligosaccharide; D007444:Inulin
keywords: Cytokines; Intestinal epithelial cells; NF-κB; Prebiotic; Toll-like receptor 4