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Rodrat M, Jantarajit W, Ng DRS, Harvey BSJ, Liu J, Wilkinson WJ, Charoenphandhu N, Sheppard DN. Carbon monoxide-releasing molecules inhibit the cystic fibrosis transmembrane conductance regulator Cl - channel. Am J Physiol Lung Cell Mol Physiol 2020; 319:L997-L1009. [PMID: 32936026 DOI: 10.1152/ajplung.00440.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The gasotransmitter carbon monoxide (CO) regulates fluid and electrolyte movements across epithelial tissues. However, its action on anion channels is incompletely understood. Here, we investigate the direct action of CO on the cystic fibrosis transmembrane conductance regulator (CFTR) by applying CO-releasing molecules (CO-RMs) to the intracellular side of excised inside-out membrane patches from cells heterologously expressing wild-type human CFTR. Addition of increasing concentrations of tricarbonyldichlororuthenium(II) dimer (CORM-2) (1-300 μM) inhibited CFTR channel activity, whereas the control RuCl3 (100 μM) was without effect. CORM-2 predominantly inhibited CFTR by decreasing the frequency of channel openings and, hence, open probability (Po). But, it also reduced current flow through open channels with very fast kinetics, particularly at elevated concentrations. By contrast, the chemically distinct CO-releasing molecule CORM-3 inhibited CFTR by decreasing Po without altering current flow through open channels. Neither depolarizing the membrane voltage nor raising the ATP concentration on the intracellular side of the membrane affected CFTR inhibition by CORM-2. Interestingly, CFTR inhibition by CORM-2, but not by CFTRinh-172, was prevented by prior enhancement of channel activity by the clinically approved CFTR potentiator ivacaftor. Similarly, when added after CORM-2, ivacaftor completely relieved CFTR inhibition. In conclusion, CORM-2 has complex effects on wild-type human CFTR consistent with allosteric inhibition and open-channel blockade. Inhibition of CFTR by CO-releasing molecules suggests that CO regulates CFTR activity and that the gasotransmitter has tissue-specific effects on epithelial ion transport. The action of ivacaftor on CFTR Cl- channels inhibited by CO potentially expands the drug's clinical utility.
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Affiliation(s)
- Mayuree Rodrat
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Walailak Jantarajit
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom.,Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand
| | - Demi R S Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Bartholomew S J Harvey
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Jia Liu
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | | | - Narattaphol Charoenphandhu
- Center of Calcium and Bone Research (COCAB), Faculty of Science, Mahidol University, Bangkok, Thailand.,Department of Physiology, Faculty of Science, Mahidol University, Bangkok, Thailand.,Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.,The Academy of Science, The Royal Society of Thailand, Dusit, Bangkok, Thailand
| | - David N Sheppard
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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Kaewsaro K, Nualplub S, Bumrungsri S, Khuituan P. Furosemide suppresses ileal and colonic contractility via interactions with GABA-A receptor in mice. Clin Exp Pharmacol Physiol 2017; 44:1155-1165. [DOI: 10.1111/1440-1681.12824] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 06/28/2017] [Accepted: 07/19/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Kannaree Kaewsaro
- Department of Physiology; Faculty of Science; Prince of Songkla University; Hat Yai Songkhla Thailand
- Department of Biology, Faculty of Science; Prince of Songkla University; Hat Yai Songkhla Thailand
| | - Suparp Nualplub
- Department of Physiology; Faculty of Science; Prince of Songkla University; Hat Yai Songkhla Thailand
| | - Sara Bumrungsri
- Department of Biology, Faculty of Science; Prince of Songkla University; Hat Yai Songkhla Thailand
| | - Pissared Khuituan
- Department of Physiology; Faculty of Science; Prince of Songkla University; Hat Yai Songkhla Thailand
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Valinsky WC, Touyz RM, Shrier A. Characterization of constitutive and acid-induced outwardly rectifying chloride currents in immortalized mouse distal tubular cells. Biochim Biophys Acta Gen Subj 2017; 1861:2007-2019. [PMID: 28483640 PMCID: PMC5482324 DOI: 10.1016/j.bbagen.2017.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 04/12/2017] [Accepted: 05/04/2017] [Indexed: 12/13/2022]
Abstract
Thiazides block Na+ reabsorption while enhancing Ca2+ 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 Ca2+ 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 [Ca2+]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. MDCT cells express a dominant NPPB-sensitive Cl− current at pH 7.4. The constitutive Cl− current (pH 7.4) does not arise from ClC-K2/barttin. MDCT cells also express an acid-induced NPPB-sensitive Cl− current (pH < 5.5). Both the constitutive and acid-induced Cl− currents are unique. mIMCD-3 cells express currents with similar biophysical properties.
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Affiliation(s)
- William C Valinsky
- Department of Physiology, McGill University, 3649 Promenade sir William Osler, Montreal, Quebec H3G 0B1, Canada
| | - Rhian M Touyz
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF GCRC, 126 University Place, Glasgow G12 8TA, United Kingdom
| | - Alvin Shrier
- Department of Physiology, McGill University, 3649 Promenade sir William Osler, Montreal, Quebec H3G 0B1, Canada.
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