Effect of Alcohol on miR-212 Expression in Intestinal Epithelial Cells and Its Potential Role in Alcoholic Liver Disease

Authors

  • Yueming Tang,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Ali Banan,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Christopher B. Forsyth,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Jeremy Z. Fields,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Cynthia K. Lau,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Li Juan Zhang,

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • Ali Keshavarzian

    1. From the Division of Digestive Disease and Nutrition, Department of Internal Medicine (YT, AB, CBF, JZF, CKL, LJZ, AK); Department of Pharmacology (AB, AK); and Department of Physiology (AK), Rush University Medical Center, Chicago, Illinois.
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  • No conflicts of interest exist.

Reprint requests: Yueming Tang, MD PhD, Assistant Professor of Medicine, Section of Gastroenterology, Department of Internal Medicine, Rush University Medical Center, 1725 W. Harrison (Suite 206), Chicago, IL 60612; Fax: 312-942-5664; E-mail: yueming_tang@rush.edu

Abstract

Background and Aims:  Alcohol-induced gut leakiness is a key factor in alcoholic liver disease (ALD); it allows endotoxin to enter the circulation and initiate liver damage. Zonula occludens 1 (ZO-1) protein is a major component of tight junctions that regulates intestinal permeability. microRNAs (miRNAs) are recently discovered regulatory molecules that inhibit expression of their target genes. The aims of our study were: (i) to investigate the effect of alcohol on miRNA-212 (miR-212) and on expression of its predicted target gene, ZO-1, (ii) to study the potential role of miR-212 in the pathophysiology of ALD in man.

Methods:  Using a TaqMan miRNA assay system, we measured miR-212 expression levels in colon biopsy samples from patients with ALD and in Caco-2 cells (a human intestinal epithelial cell line) treated with or without EtOH. We measured ZO-1 protein levels using western blots. ZO-1 mRNA was assayed using real-time PCR. Intestinal barrier integrity was measured using fluorescein sulfonic acid clearance and immunofluorescent staining for ZO-1.

Results:  Ethanol increased miR-212 expression, decreased ZO-1 protein levels, disrupted tight junctions, and increased the permeability of monolayers of Caco-2 cells. An miR-212 over-expression is correlated with hyperpermeability of the monolayer barrier. miR-212 levels were higher in colon biopsy samples in patients with ALD than in healthy controls; ZO-1 protein levels were lower.

Conclusion:  These data suggest a novel mechanism for alcohol-induced gut leakiness, one in which EtOH induces miR-212 over-expression which causes gut leakiness by down-regulating ZO-1 translation. This mechanism is a potential therapeutic target for leaky gut in patients with or at risk for ALD.

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