title: Down-regulation of monocarboxylate transporter 1 (MCT1) gene expression in the colon of piglets is linked to bacterial protein fermentation and pro-inflammatory cytokine-mediated signalling.
abstract: The present study investigated the influence of bacterial metabolites on monocarboxylate transporter 1 (MCT1) expression in pigs using in vivo, ex vivo and in vitro approaches. Piglets (n 24) were fed high-protein (26 %) or low-protein (18 %) diets with or without fermentable carbohydrates. Colonic digesta samples were analysed for a broad range of bacterial metabolites. The expression of MCT1, TNF-α, interferon γ (IFN-γ) and IL-8 was determined in colonic tissue. The expression of MCT1 was lower and of TNF-α and IL-8 was higher with high-protein diets (P< 0·05). MCT1 expression was positively correlated with l-lactate, whereas negatively correlated with NH₃ and putrescine (P< 0·05). The expression of IL-8 and TNF-α was negatively correlated with l-lactate and positively correlated with NH₃ and putrescine, whereas the expression of IFN-γ was positively correlated with histamine and 4-ethylphenol (P< 0·05). Subsequently, porcine colonic tissue and Caco-2 cells were incubated with Na-butyrate, NH₄Cl or TNF-α as selected bacterial metabolites or mediators of inflammation. Colonic MCT1 expression was higher after incubation with Na-butyrate (P< 0·05) and lower after incubation with NH₄Cl or TNF-α (P< 0·05). Incubation of Caco-2 cells with increasing concentrations of these metabolites confirmed the up-regulation of MCT1 expression by Na-butyrate (linear, P< 0·05) and down-regulation by TNF-α and NH₄Cl (linear, P< 0·05). The high-protein diet decreased the expression of MCT1 in the colon of pigs, which appears to be linked to NH₃- and TNF-α-mediated signalling.
authors: Department of Veterinary Medicine,Institute of Animal Nutrition, Freie Universität Berlin,Königin-Luise-Strasse 49,D-14195Berlin,Germany.
authors: Carmen
authors: C
authors: Villodre Tudela
authors: Animal Science Unit, Gembloux Agro-Bio Tech, University of Liège,Passage des Déportés 2,5030Gembloux,Belgium.
authors: Christelle
authors: C
authors: Boudry
authors: Department of Veterinary Medicine,Institute of Veterinary Physiology, Freie Universität Berlin,Oertzenweg 19b,D-14163Berlin,Germany.
authors: Friederike
authors: F
authors: Stumpff
authors: Department of Veterinary Medicine,Institute of Veterinary Physiology, Freie Universität Berlin,Oertzenweg 19b,D-14163Berlin,Germany.
authors: Jörg R
authors: JR
authors: Aschenbach
authors: Department of Veterinary Medicine,Institute of Animal Nutrition, Freie Universität Berlin,Königin-Luise-Strasse 49,D-14195Berlin,Germany.
authors: Wilfried
authors: W
authors: Vahjen
authors: Department of Veterinary Medicine,Institute of Animal Nutrition, Freie Universität Berlin,Königin-Luise-Strasse 49,D-14195Berlin,Germany.
authors: Jürgen
authors: J
authors: Zentek
authors: Department of Veterinary Medicine,Institute of Animal Nutrition, Freie Universität Berlin,Königin-Luise-Strasse 49,D-14195Berlin,Germany.
authors: Robert
authors: R
authors: Pieper
mesh_terms: D000818:Animals; D018938:Caco-2 Cells; D003106:Colon / Q000254:growth & development / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D003433:Crosses, Genetic; D016207:Cytokines / Q000378:metabolism*; D004040:Dietary Carbohydrates / Q000009:adverse effects / Q000378:metabolism; D004044:Dietary Proteins / Q000009:adverse effects / Q000378:metabolism*; D002149:Energy Intake; D005260:Female; D005285:Fermentation; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007413:Intestinal Mucosa / Q000254:growth & development / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology; D008297:Male; D027501:Monocarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism*; D011897:Random Allocation; D015398:Signal Transduction; D034421:Sus scrofa; D027981:Symporters / Q000235:genetics / Q000378:metabolism*; D014886:Weaning; D015430:Weight Gain; D000099233:Monocarboxylate Transport Protein 1
chemical_list: D016207:Cytokines; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D027501:Monocarboxylic Acid Transporters; D027981:Symporters; D000099233:Monocarboxylate Transport Protein 1
keywords: Ammonia