title: A renal-like organic anion transport system in the ciliary epithelium of the bovine and human eye.
abstract: The purpose of this study was to determine the direction of organic anion (OA) transport across the ciliary body and the transport proteins that may contribute. Transport of several OAs across the bovine ciliary body was examined using ciliary body sections mounted in Ussing chambers and a perfused eye preparation. Microarray, reverse-transcription polymerase chain reaction (RT-PCR), immunoblotting, and immunohistochemistry were used to examine OA transporter expression in human ocular tissues. Microarray analysis showed that many OA transporters common to other barrier epithelia are expressed in ocular tissues. mRNA (RT-PCR) and protein (immunoblotting) for OAT1, OAT3, NaDC3, and MRP4 were detected in extracts of the human ciliary body from several donors. OAT1 and OAT3 localized to basolateral membranes of nonpigmented epithelial cells and MRP4 to basolateral membranes of pigmented cells in the human eye. Para-aminohippurate (PAH) and estrone-3-sulfate transport across the bovine ciliary body in the Ussing chambers was greater in the aqueous humor-to-blood direction than in the blood-to-aqueous humor direction, and active. There was little net directional movement of cidofovir. Probenecid (0.1 mM) or novobiocin (0.1 mM) added to the aqueous humor side of the tissue, or MK571 (5-(3-(2-(7-chloroquinolin-2-yl)ethenyl)phenyl)-8-dimethylcarbamyl-4,6-dithiaoctanoic acid; 0.1 mM) added to the blood side significantly reduced net active PAH transport. The rate of 6-carboxyfluorescein elimination from the aqueous humor of the perfused eye was reduced 80% when novobiocin (0.1 mM) was present in the aqueous humor. These data indicate that the ciliary body expresses a variety of OA transporters, including those common to the kidney. They are likely involved in clearing potentially harmful endobiotic and xenobiotic OAs from the eye.
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.).
authors: Jonghwa
authors: J
authors: Lee
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.).
authors: Mohammad
authors: M
authors: Shahidullah
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.).
authors: Adam
authors: A
authors: Hotchkiss
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.).
authors: Miguel
authors: M
authors: Coca-Prados
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.).
authors: Nicholas A
authors: NA
authors: Delamere
authors: Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada (J.L., A.H., R.M.P.); Department of Physiology, University of Arizona, Tucson, Arizona (M.S., N.A.D.); and Department of Ophthalmology and Visual Sciences, Yale University, New Haven, Connecticut (M.C.-P.) Ryan.pelis@dal.ca.
authors: Ryan M
authors: RM
authors: Pelis
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D002417:Cattle; D002924:Ciliary Body / Q000378:metabolism*; D029382:Dicarboxylic Acid Transporters / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007672:Kidney Cortex / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D027362:Organic Anion Transport Protein 1 / Q000235:genetics / Q000378:metabolism; D027361:Organic Anion Transporters / Q000235:genetics / Q000378:metabolism*; D029363:Organic Anion Transporters, Sodium-Dependent / Q000235:genetics / Q000378:metabolism; D029362:Organic Anion Transporters, Sodium-Independent / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D055213:Retinal Pigment Epithelium / Q000378:metabolism*; D027981:Symporters / Q000235:genetics / Q000378:metabolism
chemical_list: D029382:Dicarboxylic Acid Transporters; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D027362:Organic Anion Transport Protein 1; D027361:Organic Anion Transporters; D029363:Organic Anion Transporters, Sodium-Dependent; D029362:Organic Anion Transporters, Sodium-Independent; D012333:RNA, Messenger; D027981:Symporters; C073492:ABCC4 protein, human; C092524:SLC13A2 protein, human; C114338:organic anion transport protein 3