Effects of phenol on barrier function of a human intestinal epithelial cell line correlate with altered tight junction protein localization

• Published in: Toxicology and applied pharmacology Vol. 241; no. 1; pp. 61 - 70
• Main Authors: McCall, Ingrid C., Betanzos, Abigail, Weber, Dominique A., Nava, Porfirio, Miller, Gary W., Parkos, Charles A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Inc 15.11.2009; Elsevier
• Subjects: 60 APPLIED LIFE SCIENCES; AMINES; ANIMAL TISSUES; ANIMALS; APOPTOSIS; AROMATICS; AZO COMPOUNDS; AZO DYES; Biological and medical sciences; BLOOD SUBSTITUTES; Blotting, Western; BODY; CARBOHYDRATES; CELL CONSTITUENTS; Cell Line; CELL MEMBRANES; Cell Survival - drug effects; Cell viability; DEXTRAN; Dextrans - metabolism; DIGESTIVE SYSTEM; Dose-Response Relationship, Drug; DOSES; DRUGS; DYES; Electric Impedance; Epithelial Cells - drug effects; Epithelial Cells - metabolism; Epithelial paracellular barrier; EPITHELIUM; Fluorescein-5-isothiocyanate - analogs & derivatives; Fluorescein-5-isothiocyanate - metabolism; Fluorescent Antibody Technique; GASTROINTESTINAL TRACT; Gene Expression Regulation - drug effects; HALIDES; HALOGEN COMPOUNDS; HEMATOLOGIC AGENTS; Humans; HYDROXY COMPOUNDS; IN VITRO; Intestinal Mucosa - drug effects; Intestinal Mucosa - metabolism; INTESTINES; IODIDES; IODINE COMPOUNDS; MALES; MAMMALS; MAN; Medical sciences; Membrane Proteins - genetics; MEMBRANES; MEN; NAPHTHOLS; ORGANIC ACIDS; ORGANIC COMPOUNDS; ORGANIC NITROGEN COMPOUNDS; ORGANIC SULFUR COMPOUNDS; ORGANS; Permeability; PHENOL; Phenol - administration & dosage; Phenol - toxicity; PHENOLS; POLYSACCHARIDES; PRIMATES; PROTEINS; SACCHARIDES; SK-CO15 cells; Soil Pollutants - administration & dosage; Soil Pollutants - toxicity; SULFONIC ACIDS; Tight junctions; Tight Junctions - drug effects; Tight Junctions - metabolism; TOXICITY; Toxicology; Transepithelial electrical resistance; TRYPAN BLUE; VERTEBRATES; Water Pollutants - administration & dosage; Water Pollutants - toxicity; TER; Ab; SK-CO15 cells; Tight junctions; Epithelial paracellular barrier; Cell viability; PARP; MTT; Phenol; ZO-1; TUNEL; ZVAD; TJ; PI; JAM-A; Transepithelial electrical resistance; Human; Digestive system; Barrier function; Toxicity; Gut; Cell junction; In vitro; Gap junction; Protein; Cell line; Established cell line; Phenols; Electric resistivity; Epithelial cell; Tight junction; Localization; Viability
• ISSN: 0041-008X; 1096-0333
• DOI: 10.1016/j.taap.2009.08.002

Phenol contamination of soil and water has raised concerns among people living near phenol-producing factories and hazardous waste sites containing the chemical. Phenol, particularly in high concentrations, is an irritating and corrosive substance, making mucosal membranes targets of toxicity in humans. However, few data on the effects of phenol after oral exposure exist. We used an in vitro model employing human intestinal epithelial cells (SK-CO15) cultured on permeable supports to examine effects of phenol on epithelial barrier function. We hypothesized that phenol disrupts epithelial barrier by altering tight junction (TJ) protein expression. The dose-response effect of phenol on epithelial barrier function was determined using transepithelial electrical resistance (TER) and FITC-dextran permeability measurements. We studied phenol-induced changes in cell morphology and expression of several tight junction proteins by immunofluorescence and Western blot analysis. Effects on cell viability were assessed by MTT, Trypan blue, propidium iodide and TUNEL staining. Exposure to phenol resulted in decreased TER and increased paracellular flux of FITC-dextran in a dose-dependent manner. Delocalization of claudin-1 and ZO-1 from TJs to cytosol correlated with the observed increase in permeability after phenol treatment. Additionally, the decrease in TER correlated with changes in the distribution of a membrane raft marker, suggesting phenol-mediated effects on membrane fluidity. Such observations were independent of effects of phenol on cell viability as enhanced permeability occurred at doses of phenol that did not cause cell death. Overall, these findings suggest that phenol may affect transiently the lipid bilayer of the cell membrane, thus destabilizing TJ-containing microdomains.