title: MDCK cells are capable of water secretion and reabsorption in response to changes in the ionic environment.
abstract: A prerequisite for tissue electrolyte homeostasis is highly regulated ion and water transport through kidney or intestinal epithelia. In the present work, we monitored changes in the cell and luminal volumes of type II Madin-Darby canine kidney (MDCK) cells grown in a 3D environment in response to drugs, or to changes in the composition of the basal extracellular fluid. Using fluorescent markers and high-resolution spinning disc confocal microscopy, we could show that lack of sodium and potassium ions in the basal fluid (tetramethylammonium chloride (TMACl) buffer) induces a rapid increase in the cell and luminal volumes. This transepithelial water flow could be regulated by inhibitors and agonists of chloride channels. Hence, the driving force for the transepithelial water flow is chloride secretion, stimulated by hyperpolarization. Chloride ion depletion of the basal fluid (using sodium gluconate buffer) induces a strong reduction in the lumen size, indicating reabsorption of water from the lumen to the basal side. Lumen size also decreased following depolarization of the cell interior by rendering the membrane permeable to potassium. Hence, MDCK cells are capable of both absorption and secretion of chloride ions and water; negative potential within the lumen supports secretion, while depolarizing conditions promote reabsorption.
authors.affiliation: Biocenter Oulu and the Institute of Diagnostics, University of Oulu, Oulu, Finland.|Biocenter Oulu and the Institute of Diagnostics, University of Oulu, Oulu, Finland.
authors.forename: Janne P
authors.initials: JP
authors.lastname: Capra
authors.affiliation: Biocenter Oulu and the Institute of Diagnostics, University of Oulu, Oulu, Finland.|Biocenter Oulu and the Institute of Diagnostics, University of Oulu, Oulu, Finland.
authors.forename: Sinikka M
authors.initials: SM
authors.lastname: Eskelinen
mesh_terms: D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D065101:Chloride Channel Agonists / Q000494:pharmacology; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000502:physiology; D002712:Chlorides / Q000502:physiology*; D005576:Colforsin / Q000494:pharmacology; D004285:Dogs; D000068238:Lubiprostone / Q000494:pharmacology; D061985:Madin Darby Canine Kidney Cells; D008564:Membrane Potentials / Q000502:physiology; D018613:Microscopy, Confocal; D009550:Nigericin / Q000494:pharmacology; D011188:Potassium / Q000502:physiology*; D065608:Renal Reabsorption / Q000502:physiology*; D012964:Sodium / Q000502:physiology*; D053778:Thiazolidines / Q000494:pharmacology; D016707:Tissue Fixation; D014867:Water / Q000502:physiology*
chemical_list: C482900:3-((3-trifluoromethyl)phenyl)-5-((3-carboxyphenyl)methylene)-2-thioxo-4-thiazolidinone; D001565:Benzoates; D065101:Chloride Channel Agonists; D018118:Chloride Channels; D002712:Chlorides; D053778:Thiazolidines; D014867:Water; D005576:Colforsin; D000068238:Lubiprostone; D012964:Sodium; D009550:Nigericin; D011188:Potassium
keywords: 3D cell culture; cellules épithéliales rénales; chloride secretion; culture cellulaire 3D; depolarization; dépolarisation; hyperpolarisation; hyperpolarization; kidney epithelial cells; microscopie confocale à disque rotatif; spinning disc confocal microscopy; sécrétion de chlore; transepithelial water transport; transport transépithélial de l’eau