1. EGF receptor plays a role in the mechanism of glutamine-mediated prevention of alcohol-induced gut barrier dysfunction and liver injury.
- Author
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Meena, Avtar S., Shukla, Pradeep K., Sheth, Parimal, and Rao, RadhaKrishna
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LIVER injuries , *EPIDERMAL growth factor receptors , *GLUTAMINE , *ALCOHOL-induced disorders , *TRIGLYCERIDES , *GLUTAMINE metabolism , *ENDOTOXEMIA prevention , *GASTROINTESTINAL system , *CYTOKINES , *COLON (Anatomy) , *CELL membranes , *CELL receptors , *ANTIOXIDANTS , *MICROFILAMENT proteins , *RESEARCH funding , *ETHANOL , *INTESTINAL mucosa , *CHEMOKINES , *MICE , *ANIMALS - Abstract
Recent study indicated that glutamine prevents alcoholic tissue injury in mouse gut and liver. Here we investigated the potential role of Epidermal Growth Factor Receptor (EGFR) in glutamine-mediated prevention of ethanol-induced colonic barrier dysfunction, endotoxemia and liver damage. Wild-type and EGFR*Tg transgenic (expressing dominant negative EGFR) mice were fed 1-6% ethanol in Lieber-DeCarli diet. Gut permeability was measured by vascular-to-luminal flux of FITC-inulin, and junctional integrity assessed by confocal microscopy. Liver injury was evaluated by plasma transaminases, histopathology and triglyceride analyses. Glutamine effect on acetaldehyde-induced tight junction disruption was investigated in Caco-2 cell monolayers. Doxycycline-induced expression of EGFR* blocked glutamine-mediated prevention of ethanol-induced disruption of colonic epithelial tight junction, mucosal permeability and endotoxemia. Ethanol activated cofilin and disrupted actin cytoskeleton, which was blocked by glutamine in an EGFR-dependent mechanism. Ethanol down-regulated antioxidant gene expression and up-regulated cytokine and chemokine gene expression, which were blocked by glutamine in wild-type mice in the presence or absence of doxycycline, but not in EGFR*Tg mice in the presence of doxycycline. Histopathology, plasma transaminases, triglyceride and expression of chemokine and antioxidant genes indicated ethanol-induced liver damage, which were blocked by glutamine in an EGFR-dependent mechanism. Src kinase activity and extracellular ligand binding domain of EGFR are required for glutamine-mediated protection of barrier function in Caco-2 cell monolayers. Glutamine released metalloproteinases into the medium, and metalloproteinase inhibitors blocked glutamine-mediated protection of barrier function. Results demonstrate that EGFR plays an important role in glutamine-mediated prevention of alcoholic gut permeability, endotoxemia and liver damage. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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