title: Functional and pharmacological characterization of volume-regulated anion channels in human normal and cystic fibrosis bronchial and nasal epithelial cells.
abstract: Volume-regulated anion channels (VRACs) are widely present in various cell types and have important functions ranging from regulatory volume decrease to control of cell proliferation and apoptosis. Here we aimed to compare the biophysical features and pharmacological profiles of VRAC currents in healthy and cystic fibrosis (CF) respiratory epithelial cells in order to characterize these currents both functionally and pharmacologically. Whole-cell electrophysiology was used to characterize the VRAC current in normal (16HBE14o-; HBE) and CF cell lines (CFBE14o-; CFBE), as well as in native human nasal epithelial cells. Application of hypotonic solution produced current responses of similar sizes in both HBE and CFBE cells. Biophysical properties of VRACs, such as instantaneous activation and deactivation upon voltage step, some inactivation at potentials positive to 40 mV and outwardly-rectifying I-V curves, were indistinguishable in both cell types. Extensive pharmacological analysis of the currents revealed a similar pharmacological profile in response to three blockers--NPPB, DCPIB and DIDS. Native primary human nasal epithelial cells from both healthy and CF volunteers also showed typical VRAC responses of comparable sizes. VRACs in these cells were more sensitive to external solution hypotonicity compared to HBE and CFBE cells. In all cell types studied robust VRAC currents could be induced at constant cell volume by G-protein activation with GTPγS infusion. This study provides the first extensive comparative functional and pharmacological analysis of VRAC currents in normal and CF airway epithelial cells and shows that VRACs are unimpaired molecularly or functionally in CF.
authors.affiliation: Centre for Infection and Immunity, Health Sciences Building, Queen׳s University Belfast, Belfast BT9 7AE, UK; Centre for Experimental Medicine, ICS-A, Queen׳s University Belfast, Belfast BT12 6BA, UK.
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Stott
authors.affiliation: Centre for Infection and Immunity, Health Sciences Building, Queen׳s University Belfast, Belfast BT9 7AE, UK.
authors.forename: Francine
authors.initials: F
authors.lastname: deCourcey
authors.affiliation: Centre for Infection and Immunity, Health Sciences Building, Queen׳s University Belfast, Belfast BT9 7AE, UK.
authors.forename: Madeleine
authors.initials: M
authors.lastname: Ennis
authors.affiliation: Institute of Biology, Taras Shevchenko Kiev National University, 2 Academician Glushkov Avenue, Kiev 01601, Ukraine. Electronic address: a.zholos@univ.net.ua.
authors.forename: Alexander V
authors.initials: AV
authors.lastname: Zholos
mesh_terms: D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid / Q000494:pharmacology; D001980:Bronchi / Q000166:cytology; D002460:Cell Line; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000502:physiology*; D003517:Cyclopentanes / Q000494:pharmacology; D003550:Cystic Fibrosis / Q000503:physiopathology; D004847:Epithelial Cells / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D007189:Indans / Q000494:pharmacology; D049990:Membrane Transport Modulators / Q000494:pharmacology; D009297:Nasal Mucosa / Q000166:cytology; D009579:Nitrobenzoates / Q000494:pharmacology
chemical_list: C443139:4-(2-butyl-6,7-dichlor-2-cyclopentyl-indan-1-one-5-yl)oxybutyric acid; D018118:Chloride Channels; D003517:Cyclopentanes; D007189:Indans; D049990:Membrane Transport Modulators; D009579:Nitrobenzoates; C058176:5-nitro-2-(3-phenylpropylamino)benzoic acid; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid
keywords: Bronchial epithelial cells; Cystic fibrosis; DCPIB (PubChem CID: 10071166); DIDS (PubChem CID: 5281951); NPPB ((PubChem CID: 4549); Nasal epithelial cells; Volume-regulated anion current