title: Bile acid modulates transepithelial permeability via the generation of reactive oxygen species in the Caco-2 cell line.
abstract: The barrier functions in epithelial and endothelial cells seem to be very important for maintaining normal biological homeostasis. However, it is unclear whether or how bile acids affect the epithelial barrier. We examined the bile acid-induced disruption of the epithelial barrier. We measured the transepithelial electrical resistance (TEER) of Caco-2 cells as a marker of disruption of the epithelial barrier. Reactive oxygen species (ROS) generation was also measured. Cholic acid (CA) decreased the TEER and increased intracellular ROS generation. PLA2 (phospholipase A2), COX (cyclooxygenase), PKC (protein kinase), ERK 1/2 (extracellular signal-regulated kinase 1/2), PI 3 K (phosphatidylinositol 3-kinase), p38 MAPK (p38 mitogen-activated protein kinase), MLCK (myosin light-chain kinase), NADH dehydrogenase, and XO (xanthine oxidase) inhibitors or ROS scavengers prevented the CA-induced TEER decrease. PLA2, COX, PKC, NADH dehydrogenase, and XO inhibitors prevented the CA-induced ROS generation but not ERK 1/2, PI 3 K, p38 MAPK, and MLCK inhibitors. If the cells were treated with ROS generators such as superoxide dismutase, the TEER decreased. ERK 1/2, PI 3 K, p38 MAPK, and MLCK inhibitors prevent these ROS generators from inducing the TEER decrease. These results suggest that ROS play an important role. In addition, PLA2, COX, PKC, NADH dehydrogenase, and XO are located upstream of the ROS generation, but ERK 1/2, PI 3 K, p38 MAPK, and MLCK are downstream during the signaling of CA-induced TEER alterations.
authors.affiliation: Department of Internal Medicine, Biwako Youikuin Hospital, 7-7-2 Ohgaya, Otsu 520-2144 Shiga, Japan. bileacidaraki@hotmail.com
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Araki
authors.forename: Takuji
authors.initials: T
authors.lastname: Katoh
authors.forename: Atsushi
authors.initials: A
authors.lastname: Ogawa
authors.forename: Shigeki
authors.initials: S
authors.lastname: Bamba
authors.forename: Akira
authors.initials: A
authors.lastname: Andoh
authors.forename: Shigeki
authors.initials: S
authors.lastname: Koyama
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Fujiyama
authors.forename: Tadao
authors.initials: T
authors.lastname: Bamba
mesh_terms: D001647:Bile Acids and Salts / Q000378:metabolism*; D018938:Caco-2 Cells; D002374:Catalase / Q000037:antagonists & inhibitors; D045744:Cell Line, Tumor; D019826:Cholic Acid / Q000494:pharmacology; D017097:Electric Impedance; D004847:Epithelial Cells / Q000166:cytology*; D004848:Epithelium / Q000378:metabolism; D006801:Humans; D008856:Microscopy, Fluorescence; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D008954:Models, Biological; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism; D009245:NADH Dehydrogenase / Q000378:metabolism; D010539:Permeability; D010741:Phospholipases A / Q000378:metabolism; D054467:Phospholipases A2; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D017382:Reactive Oxygen Species; D015398:Signal Transduction; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors; D014969:Xanthine Oxidase / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D017382:Reactive Oxygen Species; D002374:Catalase; D011451:Prostaglandin-Endoperoxide Synthases; D013482:Superoxide Dismutase; D014969:Xanthine Oxidase; D009245:NADH Dehydrogenase; D011493:Protein Kinase C; D009219:Myosin-Light-Chain Kinase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048051:p38 Mitogen-Activated Protein Kinases; D010741:Phospholipases A; D054467:Phospholipases A2; D019826:Cholic Acid