Tags

Type your tag names separated by a space and hit enter

Ethanol modulation of intestinal epithelial tight junction barrier.
Am J Physiol. 1999 04; 276(4):G965-74.AJ

Abstract

Previous studies have shown that high concentrations of ethanol (>/=40%) cause functional damage of the gastrointestinal epithelial barrier by direct cytotoxic effect on the epithelial cells. The effects of lower noncytotoxic doses of ethanol on epithelial barrier function are unknown. A major function of gastrointestinal epithelial cells is to provide a barrier against the hostile substances in the gastrointestinal lumen. The apicolaterally located tight junctions (TJs) form a paracellular seal between the lateral membranes of adjacent cells and act as a paracellular barrier. In this study, we investigated the effects of lower doses of ethanol on intestinal epithelial TJ barrier function using filter-grown Caco-2 intestinal epithelial monolayers. The Caco-2 TJ barrier function was assessed by measuring epithelial resistance or paracellular permeability of the filter-grown monolayers. Ethanol (0, 1, 2.5, 5, 7.5, and 10%) produced a dose-related drop in Caco-2 epithelial resistance and increase in paracellular permeability. Ethanol also produced a progressive disruption of TJ protein (ZO-1) with separation of ZO-1 proteins from the cellular junctions and formation of large gaps between the adjacent cells. Ethanol, at the doses used (</=10%), did not cause cytotoxicity (lactate dehydrogenase release) to the Caco-2 cells. Ethanol produced a disassembly and displacement of perijunctional actin and myosin filaments from the perijunctional areas. On ethanol removal, actin and myosin filaments rapidly reassembled at the cellular borders. Ethanol stimulated the Caco-2 myosin light chain kinase (MLCK) activity but did not affect the MLCK protein levels. Specific MLCK inhibitor ML-7 inhibited both ethanol increases in MLCK activity and TJ permeability without affecting the MLCK protein levels. Consistent with these findings, metabolic inhibitors sodium azide and 2,4-dinitrophenol significantly prevented ethanol-induced increase in Caco-2 TJ permeability, whereas cycloheximide or actinomycin D had no effect. The results of this study indicate that ethanol at low noncytotoxic doses causes a functional and structural opening of the Caco-2 intestinal epithelial TJ barrier by activating MLCK.

Authors+Show Affiliations

Division of Gastroenterology, Department of Medicine, Department of Veterans Affairs Medical Center, Long Beach 90822, USA. ma.thomas_y@long-beach.va.govNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

10198341

Citation

Ma, T Y., et al. "Ethanol Modulation of Intestinal Epithelial Tight Junction Barrier." The American Journal of Physiology, vol. 276, no. 4, 1999, pp. G965-74.
Ma TY, Nguyen D, Bui V, et al. Ethanol modulation of intestinal epithelial tight junction barrier. Am J Physiol. 1999;276(4):G965-74.
Ma, T. Y., Nguyen, D., Bui, V., Nguyen, H., & Hoa, N. (1999). Ethanol modulation of intestinal epithelial tight junction barrier. The American Journal of Physiology, 276(4), G965-74. https://doi.org/10.1152/ajpgi.1999.276.4.G965
Ma TY, et al. Ethanol Modulation of Intestinal Epithelial Tight Junction Barrier. Am J Physiol. 1999;276(4):G965-74. PubMed PMID: 10198341.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Ethanol modulation of intestinal epithelial tight junction barrier. AU - Ma,T Y, AU - Nguyen,D, AU - Bui,V, AU - Nguyen,H, AU - Hoa,N, PY - 1999/4/13/pubmed PY - 1999/4/13/medline PY - 1999/4/13/entrez SP - G965 EP - 74 JF - The American journal of physiology JO - Am J Physiol VL - 276 IS - 4 N2 - Previous studies have shown that high concentrations of ethanol (>/=40%) cause functional damage of the gastrointestinal epithelial barrier by direct cytotoxic effect on the epithelial cells. The effects of lower noncytotoxic doses of ethanol on epithelial barrier function are unknown. A major function of gastrointestinal epithelial cells is to provide a barrier against the hostile substances in the gastrointestinal lumen. The apicolaterally located tight junctions (TJs) form a paracellular seal between the lateral membranes of adjacent cells and act as a paracellular barrier. In this study, we investigated the effects of lower doses of ethanol on intestinal epithelial TJ barrier function using filter-grown Caco-2 intestinal epithelial monolayers. The Caco-2 TJ barrier function was assessed by measuring epithelial resistance or paracellular permeability of the filter-grown monolayers. Ethanol (0, 1, 2.5, 5, 7.5, and 10%) produced a dose-related drop in Caco-2 epithelial resistance and increase in paracellular permeability. Ethanol also produced a progressive disruption of TJ protein (ZO-1) with separation of ZO-1 proteins from the cellular junctions and formation of large gaps between the adjacent cells. Ethanol, at the doses used (</=10%), did not cause cytotoxicity (lactate dehydrogenase release) to the Caco-2 cells. Ethanol produced a disassembly and displacement of perijunctional actin and myosin filaments from the perijunctional areas. On ethanol removal, actin and myosin filaments rapidly reassembled at the cellular borders. Ethanol stimulated the Caco-2 myosin light chain kinase (MLCK) activity but did not affect the MLCK protein levels. Specific MLCK inhibitor ML-7 inhibited both ethanol increases in MLCK activity and TJ permeability without affecting the MLCK protein levels. Consistent with these findings, metabolic inhibitors sodium azide and 2,4-dinitrophenol significantly prevented ethanol-induced increase in Caco-2 TJ permeability, whereas cycloheximide or actinomycin D had no effect. The results of this study indicate that ethanol at low noncytotoxic doses causes a functional and structural opening of the Caco-2 intestinal epithelial TJ barrier by activating MLCK. SN - 0002-9513 UR - https://www.unboundmedicine.com/medline/citation/10198341/Ethanol_modulation_of_intestinal_epithelial_tight_junction_barrier_ L2 - https://journals.physiology.org/doi/10.1152/ajpgi.1999.276.4.G965?url_ver=Z39.88-2003&amp;rfr_id=ori:rid:crossref.org&amp;rfr_dat=cr_pub=pubmed DB - PRIME DP - Unbound Medicine ER -