Short-Chain Fatty Acids Activate AMP-Activated Protein Kinase and Ameliorate Ethanol-Induced Intestinal Barrier Dysfunction in Caco-2 Cell Monolayers1,2

• Published in: The Journal of nutrition Vol. 143; no. 12; p. 1872
• Main Authors: Elamin, Elhaseen E, Masclee, Ad A, Dekker, Jan, Pieters, Harm-Jan, Jonkers, Daisy M
• Format: Journal Article
• Language: English
• Published: Bethesda American Institute of Nutrition 01.12.2013
• Subjects: Cytoskeleton; Ethanol; Experiments; Homeostasis; Kinases; Liver diseases; Metabolites; Oxidative stress; Permeability; Proteins; Small intestine; Stress; Studies
• ISSN: 0022-3166; 1541-6100

Short-chain fatty acids (SCFAs) have been shown to promote intestinal barrier function, but their protective effects against ethanol-induced intestinal injury and underlying mechanisms remain essentially unknown. The aim of the study was to analyze the influence of SCFAs on ethanol-induced barrier dysfunction and to examine the role of AMP-activated protein kinase (AMPK) as a possible mechanism using Caco-2 monolayers. The monolayers were treated apically with butyrate (2, 10, or 20 mmol/L), propionate (4, 20, or 40 mmol/L), or acetate (8, 40, or 80 mmol/L) for 1 h before ethanol (40 mmol/L) for 3 h. Barrier function was analyzed by measurement of transepithelial resistance and permeation of fluorescein isothiocyanate-labeled dextran. Distribution of the tight junction (TJ) proteins zona occludens-1, occludin, and filamentous-actin (F-actin) was examined by immunofluorescence. Metabolic stress was determined by measuring oxidative stress, mitochondrial function, and ATP using dichlorofluorescein diacetate, dimethylthiazol-2-yl-2,5-diphenyltetrazolium bromide, and biolumi-nescence assay, respectively. AMPK was knocked down by small interfering RNA (siRNA), and its activity was assessed by a cell-based ELISA. Exposure to ethanol significantly impaired barrier function compared with controls (P < 0.0001), disrupted TJ and F-actin cytoskeleton integrity, and induced metabolic stress. However, pretreatment with 2 mmol/L butyrate, 4 mmol/L propionate, and 8 mmol/L acetate significantly alleviated the ethanol-induced barrier dysfunction, TJ and F-actin disruption, and metabolic stress compared with ethanol-exposed monolayers (P < 0.0001). The promoting effects on barrier function were abolished by inhibiting AMPK using either compound C or siRNA. These observations indicate that SCFAs exhibit protective effects against ethanol-induced barrier disruption via AMPK activation, suggesting a potential for SCFAs as prophylactic and/or therapeutic factors against ethanol-induced gut leakiness. [PUBLICATION ABSTRACT]