1. 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.
- Author
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Villodre Tudela C, Boudry C, Stumpff F, Aschenbach JR, Vahjen W, Zentek J, and Pieper R
- Subjects
- Animals, Caco-2 Cells, Colon growth & development, Colon immunology, Colon microbiology, Crosses, Genetic, Dietary Carbohydrates adverse effects, Dietary Carbohydrates metabolism, Dietary Proteins adverse effects, Energy Intake, Female, Fermentation, Humans, Intestinal Mucosa growth & development, Intestinal Mucosa immunology, Intestinal Mucosa microbiology, Male, Monocarboxylic Acid Transporters genetics, Random Allocation, Sus scrofa, Symporters genetics, Weaning, Weight Gain, Colon metabolism, Cytokines metabolism, Dietary Proteins metabolism, Gene Expression Regulation, Developmental, Intestinal Mucosa metabolism, Monocarboxylic Acid Transporters metabolism, Signal Transduction, Symporters metabolism
- 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.
- Published
- 2015
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