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

• Published in: British journal of nutrition Vol. 113; no. 4; pp. 610 - 617
• Main Authors: Villodre Tudela, Carmen, Boudry, Christelle, Stumpff, Friederike, Aschenbach, Jörg R., Vahjen, Wilfried, Zentek, Jürgen, Pieper, Robert
• Format: Journal Article
• Language: English
• Published: Cambridge, UK Cambridge University Press 28-02-2015
• Subjects: Ammonia; Animals; Bacteria; Caco-2 Cells; Carbohydrates; Colon; Colon - growth & development; Colon - immunology; Colon - metabolism; Colon - microbiology; Crosses, Genetic; Cytokines - metabolism; Diet; Dietary Carbohydrates - adverse effects; Dietary Carbohydrates - metabolism; Dietary Proteins - adverse effects; Dietary Proteins - metabolism; Energy Intake; Female; Fermentation; Gene expression; Gene Expression Regulation, Developmental; Hogs; Humans; Immunology; Incubation; Intestinal Mucosa - growth & development; Intestinal Mucosa - immunology; Intestinal Mucosa - metabolism; Intestinal Mucosa - microbiology; Male; Metabolites; Monocarboxylic Acid Transporters - genetics; Monocarboxylic Acid Transporters - metabolism; Nutrition; Nutritional Immunology; Random Allocation; Signal Transduction; Sus scrofa; Symporters - genetics; Symporters - metabolism; Weaning; Weight Gain; Pigs; Dietary protein; Ammonia; TNF-α; Monocarboxylate transporter 1
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114514004231

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.