title: Galacto-oligosaccharides Protect the Intestinal Barrier by Maintaining the Tight Junction Network and Modulating the Inflammatory Responses after a Challenge with the Mycotoxin Deoxynivalenol in Human Caco-2 Cell Monolayers and B6C3F1 Mice.
abstract: BACKGROUND
  The integrity of the epithelial layer in the gastrointestinal tract protects organisms from exposure to luminal antigens, which are considered the primary cause of chronic intestinal inflammation and allergic responses. The common wheat-associated fungal toxin deoxynivalenol acts as a specific disruptor of the intestinal tight junction network and hence might contribute to the pathogenesis of inflammatory bowel diseases.
  
  
  OBJECTIVE
  The aim of the current study was to assess whether defined galacto-oligosaccharides (GOSs) can prevent deoxynivalenol-induced epithelial dysfunction.
  
  
  METHODS
  Human epithelial intestinal Caco-2 cells, pretreated with different concentrations of GOSs (0.5%, 1%, and 2%) for 24 h, were stimulated with 4.2-μM deoxynivalenol (24 h), and 6/7-wk-old male B6C3F1 mice were fed a diet supplemented with 1% GOSs for 2 wk before being orally exposed to deoxynivalenol (25 mg/kg body weight, 6 h). Barrier integrity was determined by measuring transepithelial electrical resistance (TEER) and intestinal permeability to marker molecules. A calcium switch assay was conducted to study the assembly of epithelial tight junction proteins. Alterations in tight junction and cytokine expression were assessed by quantitative reverse transcriptase-polymerase chain reaction, Western blot analysis, or ELISA, and their localization was visualized by immunofluorescence microscopy. Sections of the proximal and distal small intestine were stained with hematoxylin/eosin for histomorphometric analysis.
  
  
  RESULTS
  The in vitro data showed that medium supplemented with 2% GOSs improved tight junction assembly reaching an acceleration of 85% after 6 h (P < 0.05). In turn, GOSs prevented the deoxynivalenol-induced loss of epithelial barrier function as measured by TEER (114% of control), and paracellular flux of Lucifer yellow (82.7% of prechallenge values, P < 0.05). Moreover, GOSs stabilized the expression and cellular distribution of claudin3 and suppressed by >50% the deoxynivalenol-induced synthesis and release of interleukin-8 [IL8/chemokine CXC motif ligand (CXCL8)] (P < 0.05). In mice, GOSs prevented the deoxynivalenol-induced mRNA overexpression of claudin3 (P = 0.022) and CXCL8 homolog keratinocyte hemoattractant (Kc) (Cxcl1) (P = 0.06) as well as the deoxynivalenol-induced morphologic defects.
  
  
  CONCLUSIONS
  The results demonstrate that GOSs stimulate the tight junction assembly and in turn mitigate the deleterious effects of deoxynivalenol on the intestinal barrier of Caco-2 cells and on villus architecture of B6C3F1 mice.
authors.affiliation: Divisions of Veterinary Pharmacy, Pharmacology, and Toxicology, and Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands;
authors.forename: Peyman
authors.initials: P
authors.lastname: Akbari
authors.affiliation: Divisions of Veterinary Pharmacy, Pharmacology, and Toxicology, and S.Braber@uu.nl.
authors.forename: Saskia
authors.initials: S
authors.lastname: Braber
authors.affiliation: Divisions of Veterinary Pharmacy, Pharmacology, and Toxicology, and Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands;
authors.forename: Arash
authors.initials: A
authors.lastname: Alizadeh
authors.affiliation: Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands;
authors.forename: Kim A T
authors.initials: KA
authors.lastname: Verheijden
authors.affiliation: FrieslandCampina, Amersfoort, The Netherlands; and.
authors.forename: Margriet H C
authors.initials: MH
authors.lastname: Schoterman
authors.affiliation: Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands;
authors.forename: Aletta D
authors.initials: AD
authors.lastname: Kraneveld
authors.affiliation: Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Faculty of Science, Utrecht University, Utrecht, The Netherlands; Nutricia Research, Utrecht, The Netherlands.
authors.forename: Johan
authors.initials: J
authors.lastname: Garssen
authors.affiliation: Divisions of Veterinary Pharmacy, Pharmacology, and Toxicology, and.
authors.forename: Johanna
authors.initials: J
authors.lastname: Fink-Gremmels
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D062465:Claudin-3 / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D015212:Inflammatory Bowel Diseases / Q000188:drug therapy / Q000209:etiology; D016209:Interleukin-8 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D009844:Oligosaccharides / Q000494:pharmacology*; D010539:Permeability; D019108:Tight Junctions / Q000187:drug effects* / Q000378:metabolism; D014255:Trichothecenes / Q000633:toxicity*
chemical_list: D062465:Claudin-3; D016209:Interleukin-8; D009844:Oligosaccharides; D014255:Trichothecenes; C007262:deoxynivalenol
keywords: CXCL8; Caco-2 cells; deoxynivalenol; galacto-oligosaccharides; intestinal integrity; tight junction proteins