title: Rapid Identification of Novel Inhibitors of the Human Aquaporin-1 Water Channel.
abstract: Aquaporins (AQPs) are a family of membrane proteins that function as channels facilitating water transport in response to osmotic gradients. These play critical roles in several normal physiological and pathological states and are targets for drug discovery. Selective inhibition of the AQP1 water channel may provide a new approach for the treatment of several disorders including ocular hypertension/glaucoma, congestive heart failure, brain swelling associated with a stroke, corneal and macular edema, pulmonary edema, and otic disorders such as hearing loss and vertigo. We developed a high-throughput assay to screen a library of compounds as potential AQP1 modulators by monitoring the fluorescence dequenching of entrapped calcein in a confluent layer of AQP1-overexpressing CHO cells that were exposed to a hypotonic shock. Promising candidates were tested in a Xenopus oocyte-swelling assay, which confirmed the identification of two lead classes of compounds belonging to aromatic sulfonamides and dihydrobenzofurans with IC50 s in the low micromolar range. These selected compounds directly inhibited water transport in AQP1-enriched stripped erythrocyte ghosts and in proteoliposomes reconstituted with purified AQP1. Validation of these lead compounds, by the three independent assays, establishes a set of attractive AQP1 blockers for developing novel, small-molecule functional modulators of human AQP1.
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Rajkumar V
authors.initials: RV
authors.lastname: Patil
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Shouxi
authors.initials: S
authors.lastname: Xu
authors.affiliation: Department of Nephrology, School of Medicine, University of Utah, Salt Lake City, UT, 84132, USA.
authors.forename: Alfred N
authors.initials: AN
authors.lastname: van Hoek
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Andrew
authors.initials: A
authors.lastname: Rusinko
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Zixia
authors.initials: Z
authors.lastname: Feng
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Jesse
authors.initials: J
authors.lastname: May
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Mark
authors.initials: M
authors.lastname: Hellberg
authors.affiliation: Department of Ophthalmology, Novartis Institutes of Biomedical Research Institute, Fort Worth, TX, 76134, USA.
authors.forename: Najam A
authors.initials: NA
authors.lastname: Sharif
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Texas Southwestern Medical School, Dallas, TX, 75390, USA.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Wax
authors.affiliation: AMRI Bothell Research Center, Bothell, WA, 98021, USA.
authors.forename: Macarena
authors.initials: M
authors.lastname: Irigoyen
authors.affiliation: AMRI Bothell Research Center, Bothell, WA, 98021, USA.
authors.forename: Grant
authors.initials: G
authors.lastname: Carr
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
authors.forename: Tom
authors.initials: T
authors.lastname: Brittain
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
authors.forename: Peter
authors.initials: P
authors.lastname: Brown
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
authors.forename: Damon
authors.initials: D
authors.lastname: Colbert
authors.affiliation: Department of Physiology & Biophysics, Health Sciences Center, State University of New York, Stony Brook, NY, 11794, USA.
authors.forename: Sindhu
authors.initials: S
authors.lastname: Kumari
authors.affiliation: Department of Physiology & Biophysics, Health Sciences Center, State University of New York, Stony Brook, NY, 11794, USA.
authors.forename: Kulandaiappan
authors.initials: K
authors.lastname: Varadaraj
authors.affiliation: School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, 1142, New Zealand.
authors.forename: Alok K
authors.initials: AK
authors.lastname: Mitra
mesh_terms: D000818:Animals; D051398:Aquaporin 1 / Q000037:antagonists & inhibitors*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D006801:Humans
chemical_list: D051398:Aquaporin 1
keywords: aquaporin; drug discovery; membrane transport; protein expression; water channel