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Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells
Thiazides block Na(+) reabsorption while enhancing Ca(2+) reabsorption in the kidney. As previously demonstrated in immortalized mouse distal convoluted tubule (MDCT) cells, chlorothiazide application induced a robust plasma membrane hyperpolarization, which increased Ca(2+) uptake. This essential t...
Autores principales: | , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Elsevier Pub. Co
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482324/ https://www.ncbi.nlm.nih.gov/pubmed/28483640 http://dx.doi.org/10.1016/j.bbagen.2017.05.004 |
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author | Valinsky, William C. Touyz, Rhian M. Shrier, Alvin |
author_facet | Valinsky, William C. Touyz, Rhian M. Shrier, Alvin |
author_sort | Valinsky, William C. |
collection | PubMed |
description | Thiazides block Na(+) reabsorption while enhancing Ca(2+) reabsorption in the kidney. As previously demonstrated in immortalized mouse distal convoluted tubule (MDCT) cells, chlorothiazide application induced a robust plasma membrane hyperpolarization, which increased Ca(2+) uptake. This essential thiazide-induced hyperpolarization was prevented by the Cl(−) channel inhibitor 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), implicating NPPB-sensitive Cl(−) channels, however the nature of these Cl(−) channels has been rarely described in the literature. Here we show that MDCT cells express a dominant, outwardly rectifying Cl(−) current at extracellular pH 7.4. This constitutive Cl(−) current was more permeable to larger anions (Eisenman sequence I; I(−) > Br(−) ≥ Cl(−)) and was substantially inhibited by > 100 mM [Ca(2+)](o), which distinguished it from ClC-K2/barttin. Moreover, the constitutive Cl(−) current was blocked by NPPB, along with other Cl(−) channel inhibitors (4,4′-diisothiocyanatostilbene-2,2′-disulfonate, DIDS; flufenamic acid, FFA). Subjecting the MDCT cells to an acidic extracellular solution (pH < 5.5) induced a substantially larger outwardly rectifying NPPB-sensitive Cl(−) current. This acid-induced Cl(−) current was also anion permeable (I(−) > Br(−) > Cl(−)), but was distinguished from the constitutive Cl(−) current by its rectification characteristics, ion sensitivities, and response to FFA. In addition, we have identified similar outwardly rectifying and acid-sensitive currents in immortalized cells from the inner medullary collecting duct (mIMCD-3 cells). Expression of an acid-induced Cl(−) current would be particularly relevant in the acidic IMCD (pH < 5.5). To our knowledge, the properties of these Cl(−) currents are unique and provide the mechanisms to account for the Cl(−) efflux previously speculated to be present in MDCT cells. |
format | Online Article Text |
id | pubmed-5482324 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Elsevier Pub. Co |
record_format | MEDLINE/PubMed |
spelling | pubmed-54823242017-08-01 Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells Valinsky, William C. Touyz, Rhian M. Shrier, Alvin Biochim Biophys Acta Article Thiazides block Na(+) reabsorption while enhancing Ca(2+) reabsorption in the kidney. As previously demonstrated in immortalized mouse distal convoluted tubule (MDCT) cells, chlorothiazide application induced a robust plasma membrane hyperpolarization, which increased Ca(2+) uptake. This essential thiazide-induced hyperpolarization was prevented by the Cl(−) channel inhibitor 5-Nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), implicating NPPB-sensitive Cl(−) channels, however the nature of these Cl(−) channels has been rarely described in the literature. Here we show that MDCT cells express a dominant, outwardly rectifying Cl(−) current at extracellular pH 7.4. This constitutive Cl(−) current was more permeable to larger anions (Eisenman sequence I; I(−) > Br(−) ≥ Cl(−)) and was substantially inhibited by > 100 mM [Ca(2+)](o), which distinguished it from ClC-K2/barttin. Moreover, the constitutive Cl(−) current was blocked by NPPB, along with other Cl(−) channel inhibitors (4,4′-diisothiocyanatostilbene-2,2′-disulfonate, DIDS; flufenamic acid, FFA). Subjecting the MDCT cells to an acidic extracellular solution (pH < 5.5) induced a substantially larger outwardly rectifying NPPB-sensitive Cl(−) current. This acid-induced Cl(−) current was also anion permeable (I(−) > Br(−) > Cl(−)), but was distinguished from the constitutive Cl(−) current by its rectification characteristics, ion sensitivities, and response to FFA. In addition, we have identified similar outwardly rectifying and acid-sensitive currents in immortalized cells from the inner medullary collecting duct (mIMCD-3 cells). Expression of an acid-induced Cl(−) current would be particularly relevant in the acidic IMCD (pH < 5.5). To our knowledge, the properties of these Cl(−) currents are unique and provide the mechanisms to account for the Cl(−) efflux previously speculated to be present in MDCT cells. Elsevier Pub. Co 2017-08 /pmc/articles/PMC5482324/ /pubmed/28483640 http://dx.doi.org/10.1016/j.bbagen.2017.05.004 Text en © 2017 The Authors http://creativecommons.org/licenses/by/4.0/ This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Valinsky, William C. Touyz, Rhian M. Shrier, Alvin Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title | Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title_full | Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title_fullStr | Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title_full_unstemmed | Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title_short | Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
title_sort | characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5482324/ https://www.ncbi.nlm.nih.gov/pubmed/28483640 http://dx.doi.org/10.1016/j.bbagen.2017.05.004 |
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