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Csáki R, Nagaraj C, Almássy J, Khozeimeh MA, Jeremic D, Olschewski H, Dobolyi A, Hoetzenecker K, Olschewski A, Enyedi P, Lengyel M. The TREK-1 potassium channel is a potential pharmacological target for vasorelaxation in pulmonary hypertension. Br J Pharmacol 2024. [PMID: 38807478 DOI: 10.1111/bph.16426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 03/22/2024] [Accepted: 04/09/2024] [Indexed: 05/30/2024] Open
Abstract
BACKGROUND AND PURPOSE Pulmonary arterial hypertension (PAH) is a progressive disease in which chronic membrane potential (Em) depolarisation of the pulmonary arterial smooth muscle cells (PASMCs) causes calcium overload, a key pathological alteration. Under resting conditions, the negative Em is mainly set by two pore domain potassium (K2P) channels, of which the TASK-1 has been extensively investigated. EXPERIMENTAL APPROACH Ion channel currents and membrane potential of primary cultured human(h) PASMCs were measured using the voltage- and current clamp methods. Intracellular [Ca2+] was monitored using fluorescent microscopy. Pulmonary BP and vascular tone measurements were also performed ex vivo using a rat PAH model. KEY RESULTS TREK-1 was the most abundantly expressed K2P in hPASMCs of healthy donors and idiopathic(I) PAH patients. Background K+-current was similar in hPASMCs for both groups and significantly enhanced by the TREK activator ML-335. In donor hPASMCs, siRNA silencing or pharmacological inhibition of TREK-1 caused depolarisation, reminiscent of the electrophysiological phenotype of idiopathic PAH. ML-335 hyperpolarised donor hPASMCs and normalised the Em of IPAH hPASMCs. A close link was found between TREK-1 activity and intracellular Ca2+-signalling using a channel activator, ML-335, and an inhibitor, spadin. In the rat, ML-335 relaxed isolated pre-constricted pulmonary arteries and significantly decreased pulmonary arterial pressure in the isolated perfused lung. CONCLUSIONS AND IMPLICATIONS These data suggest that TREK-1is a key factor in Em setting and Ca2+ homeostasis of hPASMC, and therefore, essential for maintenance of a low resting pulmonary vascular tone. Thus TREK-1 may represent a new therapeutic target for PAH.
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Affiliation(s)
- Réka Csáki
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Chandran Nagaraj
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
- Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria
| | - János Almássy
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | | | - Dusan Jeremic
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Horst Olschewski
- Department of Internal Medicine, Division of Pulmonology, Medical University of Graz, Graz, Austria
| | - Alice Dobolyi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Konrad Hoetzenecker
- Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria
| | - Andrea Olschewski
- Experimental Anaesthesiology, Department of Anaesthesiology and Intensive Care Medicine, Medical University of Graz, Graz, Austria
| | - Péter Enyedi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Miklós Lengyel
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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2
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Martínez AL, Brea J, López D, Cosme N, Barro M, Monroy X, Burgueño J, Merlos M, Loza MI. In vitro models for neuropathic pain phenotypic screening in brain therapeutics. Pharmacol Res 2024; 202:107111. [PMID: 38382648 DOI: 10.1016/j.phrs.2024.107111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 02/02/2024] [Accepted: 02/18/2024] [Indexed: 02/23/2024]
Abstract
The discovery of brain therapeutics faces a significant challenge due to the low translatability of preclinical results into clinical success. To address this gap, several efforts have been made to obtain more translatable neuronal models for phenotypic screening. These models allow the selection of active compounds without predetermined knowledge of drug targets. In this review, we present an overview of various existing models within the field, examining their strengths and limitations, particularly in the context of neuropathic pain research. We illustrate the usefulness of these models through a comparative review in three crucial areas: i) the development of novel phenotypic screening strategies specifically for neuropathic pain, ii) the validation of the models for both primary and secondary screening assays, and iii) the use of the models in target deconvolution processes.
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Affiliation(s)
- A L Martínez
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain; Departamento de Farmacoloxía, Farmacia e Tecnoloxía Farmacéutica, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - J Brea
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain; Departamento de Farmacoloxía, Farmacia e Tecnoloxía Farmacéutica, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - D López
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - N Cosme
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - M Barro
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain
| | - X Monroy
- WeLab Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - J Burgueño
- WeLab Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - M Merlos
- WeLab Barcelona, Parc Científic de Barcelona, Barcelona, Spain
| | - M I Loza
- BioFarma Research Group, Centro Singular de Investigación en Medicina Molecular e Enfermidades Crónicas (CIMUS), Universidade de Santiago de Compostela, Santiago de Compostela, Spain; Instituto de Investigacións Sanitarias de Santiago de Compostela (IDIS), Santiago de Compostela, Spain; Departamento de Farmacoloxía, Farmacia e Tecnoloxía Farmacéutica, Facultade de Farmacia, Universidade de Santiago de Compostela, Santiago de Compostela, Spain.
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3
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Schroeter CB, Nelke C, Schewe M, Spohler L, Herrmann AM, Müntefering T, Huntemann N, Kuzikov M, Gribbon P, Albrecht S, Bock S, Hundehege P, Neelsen LC, Baukrowitz T, Seebohm G, Wünsch B, Bittner S, Ruck T, Budde T, Meuth SG. Validation of TREK1 ion channel activators as an immunomodulatory and neuroprotective strategy in neuroinflammation. Biol Chem 2023; 404:355-375. [PMID: 36774650 DOI: 10.1515/hsz-2022-0266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 01/16/2023] [Indexed: 02/13/2023]
Abstract
Modulation of two-pore domain potassium (K2P) channels has emerged as a novel field of therapeutic strategies as they may regulate immune cell activation and metabolism, inflammatory signals, or barrier integrity. One of these ion channels is the TWIK-related potassium channel 1 (TREK1). In the current study, we report the identification and validation of new TREK1 activators. Firstly, we used a modified potassium ion channel assay to perform high-throughput-screening of new TREK1 activators. Dose-response studies helped to identify compounds with a high separation between effectiveness and toxicity. Inside-out patch-clamp measurements of Xenopus laevis oocytes expressing TREK1 were used for further validation of these activators regarding specificity and activity. These approaches yielded three substances, E1, B3 and A2 that robustly activate TREK1. Functionally, we demonstrated that these compounds reduce levels of adhesion molecules on primary human brain and muscle endothelial cells without affecting cell viability. Finally, we studied compound A2 via voltage-clamp recordings as this activator displayed the strongest effect on adhesion molecules. Interestingly, A2 lacked TREK1 activation in the tested neuronal cell type. Taken together, this study provides data on novel TREK1 activators that might be employed to pharmacologically modulate TREK1 activity.
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Affiliation(s)
- Christina B Schroeter
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Christopher Nelke
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Marcus Schewe
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Lucas Spohler
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Alexander M Herrmann
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Thomas Müntefering
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Niklas Huntemann
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Maria Kuzikov
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Schnackenburgallee 114, D-22525 Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune mediated diseases (CIMD), Theodor-Stern-Kai 7, D-60596 Frankfurt, Germany
| | - Philip Gribbon
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Schnackenburgallee 114, D-22525 Hamburg, Germany
- Fraunhofer Cluster of Excellence for Immune mediated diseases (CIMD), Theodor-Stern-Kai 7, D-60596 Frankfurt, Germany
| | - Sarah Albrecht
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Stefanie Bock
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Petra Hundehege
- Department of Neurology with Institute for Translational Neurology, University Hospital Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Lea Christine Neelsen
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Thomas Baukrowitz
- Institute of Physiology, Christian-Albrechts University Kiel, Hermann-Rodewald-Straße 5, 24118 Kiel, Germany
| | - Guiscard Seebohm
- IfGH-Cellular Electrophysiology, Department of Cardiology and Angiology, University Hospital of Münster, Albert-Schweitzer-Campus 1, D-48149 Münster, Germany
| | - Bernhard Wünsch
- Institute for Pharmaceutical and Medicinal Chemistry, Westfälische Wilhelms-Universität Münster, Corrensstraße 48, D-48149 Münster, Germany
| | - Stefan Bittner
- Department of Neurology, University Medical Center Mainz, Langenbeckstraße 1, D-55131 Mainz, Germany
| | - Tobias Ruck
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
| | - Thomas Budde
- Institute of Physiology I, University of Münster, Robert-Koch-Straße 27A, D-48149 Münster, Germany
| | - Sven G Meuth
- Department of Neurology, Medical Faculty, Heinrich Heine University Düsseldorf, Moorenstr. 5, D-40225 Düsseldorf, Germany
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4
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Schmidpeter PAM, Petroff JT, Khajoueinejad L, Wague A, Frankfater C, Cheng WWL, Nimigean CM, Riegelhaupt PM. Membrane phospholipids control gating of the mechanosensitive potassium leak channel TREK1. Nat Commun 2023; 14:1077. [PMID: 36841877 PMCID: PMC9968290 DOI: 10.1038/s41467-023-36765-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 02/15/2023] [Indexed: 02/27/2023] Open
Abstract
Tandem pore domain (K2P) potassium channels modulate resting membrane potentials and shape cellular excitability. For the mechanosensitive subfamily of K2Ps, the composition of phospholipids within the bilayer strongly influences channel activity. To examine the molecular details of K2P lipid modulation, we solved cryo-EM structures of the TREK1 K2P channel bound to either the anionic lipid phosphatidic acid (PA) or the zwitterionic lipid phosphatidylethanolamine (PE). At the extracellular face of TREK1, a PA lipid inserts its hydrocarbon tail into a pocket behind the selectivity filter, causing a structural rearrangement that recapitulates mutations and pharmacology known to activate TREK1. At the cytoplasmic face, PA and PE lipids compete to modulate the conformation of the TREK1 TM4 gating helix. Our findings demonstrate two distinct pathways by which anionic lipids enhance TREK1 activity and provide a framework for a model that integrates lipid gating with the effects of other mechanosensitive K2P modulators.
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Affiliation(s)
| | - John T Petroff
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Leila Khajoueinejad
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Aboubacar Wague
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Cheryl Frankfater
- Department of Endocrinology, Metabolism, and Lipid Research, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Wayland W L Cheng
- Department of Anesthesiology, Washington University School of Medicine in St. Louis, St. Louis, MO, USA
| | - Crina M Nimigean
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
- Department of Physiology and Biophysics, Weill Cornell Medical College, New York, NY, USA
- Department of Biochemistry, Weill Cornell Medical College, New York, NY, USA
| | - Paul M Riegelhaupt
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA.
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5
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Benarroch E. What Is the Role of 2-Pore Domain Potassium Channels (K2P) in Pain? Neurology 2022; 99:516-521. [PMID: 36123135 DOI: 10.1212/wnl.0000000000201197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 07/15/2022] [Indexed: 11/15/2022] Open
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6
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Glial-derived neurotrophic factor regulates the expression of TREK2 in rat primary sensory neurons leading to attenuation of axotomy-induced neuropathic pain. Exp Neurol 2022; 357:114190. [PMID: 35907583 DOI: 10.1016/j.expneurol.2022.114190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Revised: 07/12/2022] [Accepted: 07/24/2022] [Indexed: 11/24/2022]
Abstract
TREK2 is a member of the 2-pore domain family of K+ channels (K2P) preferentially expressed by unmyelinated, slow-conducting and non-peptidergic isolectin B4-binding (IB4+) primary sensory neurons of the dorsal root ganglia (DRG). IB4+ neurons depend on the glial-derived neurotrophic factor (GDNF) family of ligands (GFL's) to maintain their phenotype. In our previous work, we demonstrated that 7 days after spinal nerve axotomy (SNA) of the L5 DRG, TREK2 moves away from the cell membrane resulting in a more depolarised resting membrane potential (Em). Given that axotomy deprives DRG neurons from peripherally-derived GFL's, we hypothesized that they might control the expression of TREK2. Using a combination of immunohistochemistry, immunocytochemistry, western blotting, in vivo pharmacological manipulation and behavioral tests we examined the ability of the GFL's (GDNF, neurturin and artemin) and their selective receptors (GFRα1, GFRα2 and GFRα3) to regulate the expression and function of TREK2 in the DRG. We found that TREK2 correlated strongly with the three receptors normally and ipsilaterally for all GFR's after SNA. GDNF, but not NGF, neurturin or artemin up-regulated the expression of TREK2 in cultured DRG neurons. In vivo continuous, subcutaneous administration of GDNF restored the subcellular distribution of TREK2 ipsilaterally and reversed mechanical and cold allodynia 7 days after SNA. This is the first demonstration that GDNF controls the expression of a K2P channel in nociceptors. As TREK2 controls the Em of C-nociceptors affecting their excitability, our finding has therapeutic potential in the treatment of chronic pain.
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7
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Pope L, Minor DL. The Polysite Pharmacology of TREK K 2P Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1349:51-65. [PMID: 35138610 DOI: 10.1007/978-981-16-4254-8_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
K2P (KCNK) potassium channels form "background" or "leak" currents that have critical roles in cell excitability control in the brain, cardiovascular system, and somatosensory neurons. Similar to many ion channel families, studies of K2Ps have been limited by poor pharmacology. Of six K2P subfamilies, the thermo- and mechanosensitive TREK subfamily comprising K2P2.1 (TREK-1), K2P4.1 (TRAAK), and K2P10.1 (TREK-2) are the first to have structures determined for each subfamily member. These structural studies have revealed key architectural features that underlie K2P function and have uncovered sites residing at every level of the channel structure with respect to the membrane where small molecules or lipids can control channel function. This polysite pharmacology within a relatively small (~70 kDa) ion channel comprises four structurally defined modulator binding sites that occur above (Keystone inhibitor site), at the level of (K2P modulator pocket), and below (Fenestration and Modulatory lipid sites) the C-type selectivity filter gate that is at the heart of K2P function. Uncovering this rich structural landscape provides the framework for understanding and developing subtype-selective modulators to probe K2P function that may provide leads for drugs for anesthesia, pain, arrhythmia, ischemia, and migraine.
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Affiliation(s)
- Lianne Pope
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, US
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, US. .,Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA. .,California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA, USA. .,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA. .,Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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8
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Regulation of Two-Pore-Domain Potassium TREK Channels and their Involvement in Pain Perception and Migraine. Neurosci Lett 2022; 773:136494. [DOI: 10.1016/j.neulet.2022.136494] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 01/25/2022] [Accepted: 01/26/2022] [Indexed: 02/07/2023]
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9
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Two-Pore-Domain Potassium (K 2P-) Channels: Cardiac Expression Patterns and Disease-Specific Remodelling Processes. Cells 2021; 10:cells10112914. [PMID: 34831137 PMCID: PMC8616229 DOI: 10.3390/cells10112914] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 12/23/2022] Open
Abstract
Two-pore-domain potassium (K2P-) channels conduct outward K+ currents that maintain the resting membrane potential and modulate action potential repolarization. Members of the K2P channel family are widely expressed among different human cell types and organs where they were shown to regulate important physiological processes. Their functional activity is controlled by a broad variety of different stimuli, like pH level, temperature, and mechanical stress but also by the presence of lipids or pharmacological agents. In patients suffering from cardiovascular diseases, alterations in K2P-channel expression and function have been observed, suggesting functional significance and a potential therapeutic role of these ion channels. For example, upregulation of atrial specific K2P3.1 (TASK-1) currents in atrial fibrillation (AF) patients was shown to contribute to atrial action potential duration shortening, a key feature of AF-associated atrial electrical remodelling. Therefore, targeting K2P3.1 (TASK-1) channels might constitute an intriguing strategy for AF treatment. Further, mechanoactive K2P2.1 (TREK-1) currents have been implicated in the development of cardiac hypertrophy, cardiac fibrosis and heart failure. Cardiovascular expression of other K2P channels has been described, functional evidence in cardiac tissue however remains sparse. In the present review, expression, function, and regulation of cardiovascular K2P channels are summarized and compared among different species. Remodelling patterns, observed in disease models are discussed and compared to findings from clinical patients to assess the therapeutic potential of K2P channels.
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10
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Rueda-Ruzafa L, Herrera-Pérez S, Campos-Ríos A, Lamas JA. Are TREK Channels Temperature Sensors? Front Cell Neurosci 2021; 15:744702. [PMID: 34690704 PMCID: PMC8526543 DOI: 10.3389/fncel.2021.744702] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/08/2021] [Indexed: 11/17/2022] Open
Abstract
Internal human body normal temperature fluctuates between 36.5 and 37.5°C and it is generally measured in the oral cavity. Interestingly, most electrophysiological studies on the functioning of ion channels and their role in neuronal behavior are carried out at room temperature, which usually oscillates between 22 and 24°C, even when thermosensitive channels are studied. We very often forget that if the core of the body reached that temperature, the probability of death from cardiorespiratory arrest would be extremely high. Does this mean that we are studying ion channels in dying neurons? Thousands of electrophysiological experiments carried out at these low temperatures suggest that most neurons tolerate this aggression quite well, at least for the duration of the experiments. This also seems to happen with ion channels, although studies at different temperatures indicate large changes in both, neuron and channel behavior. It is known that many chemical, physical and therefore physiological processes, depend to a great extent on body temperature. Temperature clearly affects the kinetics of numerous events such as chemical reactions or conformational changes in proteins but, what if these proteins constitute ion channels and these channels are specifically designed to detect changes in temperature? In this review, we discuss the importance of the potassium channels of the TREK subfamily, belonging to the recently discovered family of two-pore domain channels, in the transduction of thermal sensitivity in different cell types.
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Affiliation(s)
- Lola Rueda-Ruzafa
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - Salvador Herrera-Pérez
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Grupo de Neurofisiología Experimental y Circuitos Neuronales, Hospital Nacional de Parapléjicos, SESCAM, Toledo, Spain
| | - Ana Campos-Ríos
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
| | - J A Lamas
- CINBIO, Laboratory of Neuroscience, University of Vigo, Vigo, Spain.,Laboratory of Neuroscience, Galicia Sur Health Research Institute (IISGS), Vigo, Spain
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11
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Lengyel M, Enyedi P, Czirják G. Negative Influence by the Force: Mechanically Induced Hyperpolarization via K 2P Background Potassium Channels. Int J Mol Sci 2021; 22:ijms22169062. [PMID: 34445768 PMCID: PMC8396510 DOI: 10.3390/ijms22169062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
The two-pore domain K2P subunits form background (leak) potassium channels, which are characterized by constitutive, although not necessarily constant activity, at all membrane potential values. Among the fifteen pore-forming K2P subunits encoded by the KCNK genes, the three members of the TREK subfamily, TREK-1, TREK-2, and TRAAK are mechanosensitive ion channels. Mechanically induced opening of these channels generally results in outward K+ current under physiological conditions, with consequent hyperpolarization and inhibition of membrane potential-dependent cellular functions. In the past decade, great advances have been made in the investigation of the molecular determinants of mechanosensation, and members of the TREK subfamily have emerged among the best-understood examples of mammalian ion channels directly influenced by the tension of the phospholipid bilayer. In parallel, the crucial contribution of mechano-gated TREK channels to the regulation of membrane potential in several cell types has been reported. In this review, we summarize the general principles underlying the mechanical activation of K2P channels, and focus on the physiological roles of mechanically induced hyperpolarization.
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12
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Natale AM, Deal PE, Minor DL. Structural Insights into the Mechanisms and Pharmacology of K 2P Potassium Channels. J Mol Biol 2021; 433:166995. [PMID: 33887333 PMCID: PMC8436263 DOI: 10.1016/j.jmb.2021.166995] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 01/10/2023]
Abstract
Leak currents, defined as voltage and time independent flows of ions across cell membranes, are central to cellular electrical excitability control. The K2P (KCNK) potassium channel class comprises an ion channel family that produces potassium leak currents that oppose excitation and stabilize the resting membrane potential in cells in the brain, cardiovascular system, immune system, and sensory organs. Due to their widespread tissue distribution, K2Ps contribute to many physiological and pathophysiological processes including anesthesia, pain, arrythmias, ischemia, hypertension, migraine, intraocular pressure regulation, and lung injury responses. Structural studies of six homomeric K2Ps have established the basic architecture of this channel family, revealed key moving parts involved in K2P function, uncovered the importance of asymmetric pinching and dilation motions in the K2P selectivity filter (SF) C-type gate, and defined two K2P structural classes based on the absence or presence of an intracellular gate. Further, a series of structures characterizing K2P:modulator interactions have revealed a striking polysite pharmacology housed within a relatively modestly sized (~70 kDa) channel. Binding sites for small molecules or lipids that control channel function are found at every layer of the channel structure, starting from its extracellular side through the portion that interacts with the membrane bilayer inner leaflet. This framework provides the basis for understanding how gating cues sensed by different channel parts control function and how small molecules and lipids modulate K2P activity. Such knowledge should catalyze development of new K2P modulators to probe function and treat a wide range of disorders.
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Affiliation(s)
- Andrew M Natale
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - Parker E Deal
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 94158, USA; Kavli Institute for Fundamental Neuroscience University of California, San Francisco, CA 94158, USA; Molecular Biophysics and Integrated Bio-imaging Division Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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13
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Huang L, Xu G, Jiang R, Luo Y, Zuo Y, Liu J. Development of Non-opioid Analgesics Targeting Two-pore Domain Potassium Channels. Curr Neuropharmacol 2021; 20:16-26. [PMID: 33827408 PMCID: PMC9199554 DOI: 10.2174/1570159x19666210407152528] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/14/2021] [Accepted: 03/24/2021] [Indexed: 02/08/2023] Open
Abstract
Two-pore domain potassium (K2P) channels are a diverse family of potassium channels. K2P channels generate background leak potassium currents to regulate cellular excitability and are thereby involved in a wide range of neurological disorders. K2P channels are modulated by a variety of physicochemical factors such as mechanical stretch, temperature, and pH. In the the peripheral nervous system (PNS), K2P channels are widely expressed in nociceptive neurons and play a critical roles in pain perception. In this review, we summarize the recent advances in the pharmacological properties of K2P channels, with a focus on the exogenous small-molecule activators targeting K2P channels. We emphasize the subtype-selectivity, cellular and in vivo pharmacological properties of all the reported small-molecule activators. The key underlying analgesic mechanisms mediated by K2P are also summarized based on the data in the literature from studies using small-molecule activators and genetic knock-out animals. We discuss advantages and limitations of the translational perspectives of K2P in pain medicine and provide outstanding questions for future studies in the end.
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Affiliation(s)
- Lu Huang
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Guangyin Xu
- Department of Physiology and Neurobiology, Institute of Neuroscience, Medical College of Soochow University, Suzhou, 215123, Jiangsu. China
| | - Ruotian Jiang
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Yuncheng Luo
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Yunxia Zuo
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
| | - Jin Liu
- Laboratory of Anesthesia and Critical Care Medicine, National-Local Joint Engineering Research Center of Translational Medicine of Anesthesiology, West China Hospital, Sichuan University, Chengdu 610000, Sichuan. China
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14
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McCoull D, Ococks E, Large JM, Tickle DC, Mathie A, Jerman J, Wright PD. A "Target Class" Screen to Identify Activators of Two-Pore Domain Potassium (K2P) Channels. SLAS DISCOVERY 2020; 26:428-438. [PMID: 33375888 PMCID: PMC7900820 DOI: 10.1177/2472555220976126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Two-pore domain potassium (K2P) channels carry background (or leak) potassium
current and play a key role in regulating resting membrane potential and
cellular excitability. Accumulating evidence points to a role for K2Ps in human
pathophysiologies, most notably in pain and migraine, making them attractive
targets for therapeutic intervention. However, there remains a lack of selective
pharmacological tools. The aim of this work was to apply a “target class”
approach to investigate the K2P superfamily and identify novel activators across
all the described subclasses of K2P channels. Target class drug discovery allows
for the leveraging of accumulated knowledge and maximizing synergies across a
family of targets and serves as an additional approach to standard target-based
screening. A common assay platform using baculovirus (BacMam) to transiently
express K2P channels in mammalian cells and a thallium flux assay to determine
channel activity was developed, allowing the simultaneous screening of multiple
targets. Importantly, this system, by allowing precise titration of channel
function, allows optimization to facilitate the identification of activators. A
representative set of channels (THIK-1, TWIK-1, TREK-2, TASK-3, and TASK-2) were
screened against a library of Food and Drug Administration (FDA)-approved
compounds and the LifeArc Index Set. Activators were then analyzed in
concentration–response format across all channels to assess selectivity. Using
the target class approach to investigate the K2P channels has enabled us to
determine which of the K2Ps are amenable to small-molecule activation, de-risk
multiple channels from a technical point of view, and identify a diverse range
of previously undescribed pharmacology.
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Affiliation(s)
| | | | | | | | - Alistair Mathie
- Medway School of Pharmacy, University of Kent, Chatham Maritime, Kent, UK
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15
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Spitznagel BD, Mishra NM, Qunies AM, Prael FJ, Du Y, Kozek KA, Lazarenko RM, Denton JS, Emmitte KA, Weaver CD. VU0606170, a Selective Slack Channels Inhibitor, Decreases Calcium Oscillations in Cultured Cortical Neurons. ACS Chem Neurosci 2020; 11:3658-3671. [PMID: 33143429 DOI: 10.1021/acschemneuro.0c00583] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Malignant migrating partial seizures of infancy is a rare, devastating form of epilepsy most commonly associated with gain-of-function mutations in the potassium channel, Slack. Not only is this condition almost completely pharmacoresistant, there are not even selective drug-like tools available to evaluate whether inhibition of these overactivated, mutant Slack channels may represent a viable path forward toward new antiepileptic therapies. Therefore, we used a high-throughput thallium flux assay to screen a drug-like, 100 000-compound library in search of inhibitors of both wild-type and a disease-associated mutant Slack channel. Using this approach, we discovered VU0606170, a selective Slack channel inhibitor with low micromolar potency. Critically, VU0606170 also proved effective at significantly decreasing the firing rate in overexcited, spontaneously firing cortical neuron cultures. Taken together, our data provide compelling evidence that selective inhibition of Slack channel activity can be achieved with small molecules and that inhibition of Slack channel activity in neurons produces efficacy consistent with an antiepileptic effect. Thus, the identification of VU0606170 provides a much-needed tool for advancing our understanding of the role of the Slack channel in normal physiology and disease as well as its potential as a target for therapeutic intervention.
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Affiliation(s)
- Brittany D. Spitznagel
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Nigam M. Mishra
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Alshaima’a M. Qunies
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
- Graduate School of Biomedical Sciences, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - Francis J. Prael
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Yu Du
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
| | - Krystian A. Kozek
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
- Vanderbilt Medical Scientist Training Program, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Roman M. Lazarenko
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Jerod S. Denton
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Department of Anesthesiology, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Kyle A. Emmitte
- Department of Pharmaceutical Sciences, UNT System College of Pharmacy, University of North Texas Health Science Center, Fort Worth, Texas 76107, United States
| | - C. David Weaver
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, Tennessee 37240, United States
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16
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Ma Y, Luo Q, Fu J, Che Y, Guo F, Mei L, Zhang Q, Li Y, Yang H. Discovery of an Inhibitor for the TREK-1 Channel Targeting an Intermediate Transition State of Channel Gating. J Med Chem 2020; 63:10972-10983. [PMID: 32877186 DOI: 10.1021/acs.jmedchem.0c00842] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Yuqin Ma
- State Key Laboratory of Drug Research and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Qichao Luo
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
- Guangdong Engineering Technology Research Center for Big Data Precision Healthcare, Big Data Decision Institute (BDDI), Jinan University, 601 Huangpu Avenue West, Guangzhou 510632, China
| | - Jie Fu
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Yanxin Che
- State Key Laboratory of Drug Research and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Fei Guo
- State Key Laboratory of Drug Research and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Lianghe Mei
- Suzhou Institute of Drug Innovation, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 108 Yuxin Road, Suzhou, Jiangsu 215123, China
| | - Qiansen Zhang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
| | - Yang Li
- State Key Laboratory of Drug Research and CAS Key Laboratory of Receptor Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, China
| | - Huaiyu Yang
- Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241, China
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17
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Zaborska KE, Dadi PK, Dickerson MT, Nakhe AY, Thorson AS, Schaub CM, Graff SM, Stanley JE, Kondapavuluru RS, Denton JS, Jacobson DA. Lactate activation of α-cell K ATP channels inhibits glucagon secretion by hyperpolarizing the membrane potential and reducing Ca 2+ entry. Mol Metab 2020; 42:101056. [PMID: 32736089 PMCID: PMC7479281 DOI: 10.1016/j.molmet.2020.101056] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/17/2020] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
Objective Elevations in pancreatic α-cell intracellular Ca2+ ([Ca2+]i) lead to glucagon (GCG) secretion. Although glucose inhibits GCG secretion, how lactate and pyruvate control α-cell Ca2+ handling is unknown. Lactate enters cells through monocarboxylate transporters (MCTs) and is also produced during glycolysis by lactate dehydrogenase A (LDHA), an enzyme expressed in α-cells. As lactate activates ATP-sensitive K+ (KATP) channels in cardiomyocytes, lactate may also modulate α-cell KATP. Therefore, this study investigated how lactate signaling controls α-cell Ca2+ handling and GCG secretion. Methods Mouse and human islets were used in combination with confocal microscopy, electrophysiology, GCG immunoassays, and fluorescent thallium flux assays to assess α-cell Ca2+ handling, Vm, KATP currents, and GCG secretion. Results Lactate-inhibited mouse (75 ± 25%) and human (47 ± 9%) α-cell [Ca2+]i fluctuations only under low-glucose conditions (1 mM) but had no effect on β- or δ-cells [Ca2+]i. Glyburide inhibition of KATP channels restored α-cell [Ca2+]i fluctuations in the presence of lactate. Lactate transport into α-cells via MCTs hyperpolarized mouse (14 ± 1 mV) and human (12 ± 1 mV) α-cell Vm and activated KATP channels. Interestingly, pyruvate showed a similar KATP activation profile and α-cell [Ca2+]i inhibition as lactate. Lactate-induced inhibition of α-cell [Ca2+]i influx resulted in reduced GCG secretion in mouse (62 ± 6%) and human (43 ± 13%) islets. Conclusions These data demonstrate for the first time that lactate entry into α-cells through MCTs results in KATP activation, Vm hyperpolarization, reduced [Ca2+]i, and inhibition of GCG secretion. Thus, taken together, these data indicate that lactate either within α-cells and/or elevated in serum could serve as important modulators of α-cell function. Lactate reduces islet α-cell Ca2+ entry under low glucose conditions. Lactate does not alter β- or δ-cell Ca2+ handling under low glucose conditions. Lactate enters islet α-cells through monocarboxylate transporters. Lactate hyperpolarizes islet α-cell membrane potential by activating KATP channels. Lactate reduces mouse and human islet glucagon secretion.
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Affiliation(s)
- Karolina E Zaborska
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Arya Y Nakhe
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Ariel S Thorson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Charles M Schaub
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Sarah M Graff
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Jade E Stanley
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Roy S Kondapavuluru
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Jerod S Denton
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, USA
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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18
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Mathie A, Veale EL, Cunningham KP, Holden RG, Wright PD. Two-Pore Domain Potassium Channels as Drug Targets: Anesthesia and Beyond. Annu Rev Pharmacol Toxicol 2020; 61:401-420. [PMID: 32679007 DOI: 10.1146/annurev-pharmtox-030920-111536] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two-pore domain potassium (K2P) channels stabilize the resting membrane potential of both excitable and nonexcitable cells and, as such, are important regulators of cell activity. There are many conditions where pharmacological regulation of K2P channel activity would be of therapeutic benefit, including, but not limited to, atrial fibrillation, respiratory depression, pulmonary hypertension, neuropathic pain, migraine, depression, and some forms of cancer. Up until now, few if any selective pharmacological regulators of K2P channels have been available. However, recent publications of solved structures with small-molecule activators and inhibitors bound to TREK-1, TREK-2, and TASK-1 K2P channels have given insight into the pharmacophore requirements for compound binding to these sites. Together with the increasing availability of a number of novel, active, small-molecule compounds from K2P channel screening programs, these advances have opened up the possibility of rational activator and inhibitor design to selectively target K2P channels.
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Affiliation(s)
- Alistair Mathie
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Emma L Veale
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
| | - Kevin P Cunningham
- Wolfson Centre for Age-Related Diseases, King's College London, London SE1 1UL, United Kingdom
| | - Robyn G Holden
- Medway School of Pharmacy, University of Greenwich and University of Kent, Kent ME4 4TB, United Kingdom;
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19
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Lengyel M, Czirják G, Jacobson DA, Enyedi P. TRESK and TREK-2 two-pore-domain potassium channel subunits form functional heterodimers in primary somatosensory neurons. J Biol Chem 2020; 295:12408-12425. [PMID: 32641496 DOI: 10.1074/jbc.ra120.014125] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 07/06/2020] [Indexed: 01/08/2023] Open
Abstract
Two-pore-domain potassium channels (K2P) are the major determinants of the background potassium conductance. They play a crucial role in setting the resting membrane potential and regulating cellular excitability. These channels form homodimers; however, a few examples of heterodimerization have also been reported. The K2P channel subunits TRESK and TREK-2 provide the predominant background potassium current in the primary sensory neurons of the dorsal root and trigeminal ganglia. A recent study has shown that a TRESK mutation causes migraine because it leads to the formation of a dominant negative truncated TRESK fragment. Surprisingly, this fragment can also interact with TREK-2. In this study, we determined the biophysical and pharmacological properties of the TRESK/TREK-2 heterodimer using a covalently linked TRESK/TREK-2 construct to ensure the assembly of the different subunits. The tandem channel has an intermediate single-channel conductance compared with the TRESK and TREK-2 homodimers. Similar conductance values were recorded when TRESK and TREK-2 were coexpressed, demonstrating that the two subunits can spontaneously form functional heterodimers. The TRESK component confers calcineurin-dependent regulation to the heterodimer and gives rise to a pharmacological profile similar to the TRESK homodimer, whereas the presence of the TREK-2 subunit renders the channel sensitive to the selective TREK-2 activator T2A3. In trigeminal primary sensory neurons, we detected single-channel activity with biophysical and pharmacological properties similar to the TRESK/TREK-2 tandem, indicating that WT TRESK and TREK-2 subunits coassemble to form functional heterodimeric channels also in native cells.
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Affiliation(s)
- Miklós Lengyel
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Gábor Czirják
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Péter Enyedi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
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20
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Hill RZ, Bautista DM. Getting in Touch with Mechanical Pain Mechanisms. Trends Neurosci 2020; 43:311-325. [DOI: 10.1016/j.tins.2020.03.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 02/14/2020] [Accepted: 03/04/2020] [Indexed: 01/10/2023]
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21
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Paschou M, Maier L, Papazafiri P, Selescu T, Dedos SG, Babes A, Doxakis E. Neuronal microRNAs modulate TREK two-pore domain K + channel expression and current density. RNA Biol 2020; 17:651-662. [PMID: 31994436 DOI: 10.1080/15476286.2020.1722450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The TREK family of leak potassium channels has been found to play critical roles in nociception, sensitivity to general anaesthetics, neuroprotection, and memory. The three members of the family, TREK1, TREK2 and TRAAK establish the resting potential and modify the duration, frequency and amplitude of action potentials. Despite their apparent importance, the repertoire of regulatory interactions utilized by cells to control their expression is poorly understood. Herein, the contribution of miRNAs in the regulation of their post-transcriptional gene expression has been examined. Using different assays, miR-124 and to a lesser extent miR-128 and miR-183 were found to reduce TREK1 and TREK2 levels through specific binding to their 3'UTRs. In contrast, miR-9 which was predicted to bind to TRAAK 3'UTR, did not alter its expression. Expression of miR-124, miR-128 and miR-183 was found to mirror that of Trek1 and Trek2 mRNAs during brain development. Moreover, application of proinflammatory mediators in dorsal root ganglion (DRG) neurons revealed an inverse correlation between miR-124 and Trek1 and Trek2 mRNA expression. Voltage clamp recordings of TREK2-mediated currents showed that miR-124 reduced the sensitivity of TREK2-expressing cells to non-aversive warmth stimulation. Overall, these findings reveal a significant regulatory mechanism by which TREK1 and TREK2 expression and hence activity are controlled in neurons and uncover new druggable targets for analgesia and neuroprotection.Abbreviations: microRNA: miRNA; UTR: untranslated region; K2p channels: two-pore domain K+channels; DRG: dorsal root ganglion; CNS: central nervous system; FBS: fetal bovine serum; TuD: Tough Decoy; TREK: tandem P-domain weak inward rectifying K+ (TWIK)-related K+ channel 1; TRAAK: TWIK-related arachidonic acid K+.
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Affiliation(s)
- Maria Paschou
- Center for Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece.,Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Larisa Maier
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Panagiota Papazafiri
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Tudor Selescu
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Skarlatos G Dedos
- Department of Biology, National and Kapodistrian University of Athens, Athens, Greece
| | - Alexandru Babes
- Department of Anatomy, Physiology and Biophysics, Faculty of Biology, University of Bucharest, Bucharest, Romania
| | - Epaminondas Doxakis
- Center for Basic Research, Biomedical Research Foundation, Academy of Athens, Athens, Greece
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22
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Conformational changes upon gating of KirBac1.1 into an open-activated state revealed by solid-state NMR and functional assays. Proc Natl Acad Sci U S A 2020; 117:2938-2947. [PMID: 31980523 PMCID: PMC7022178 DOI: 10.1073/pnas.1915010117] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Inward rectifier K+ (Kir) channels play an important role in reestablishing the resting membrane state of the action potential of excitable cells in humans. KirBac1.1 is a prokaryotic Kir channel with a high degree of homology to human Kir channels and can be isotopically labeled in NMR quantities for structural studies. Functional assays and NMR assignments confirm that KirBac1.1 is in a constitutively conductive state. Solid-state NMR assignments further reveal alternate conformations at key sites in the protein that are well conserved through human Kir channels, hinting at a possible allosteric network between channels. These underlying sequential and structural motifs could explain abnormal conductive properties of these channels fundamental to their native gating processes. The conformational changes required for activation and K+ conduction in inward-rectifier K+ (Kir) channels are still debated. These structural changes are brought about by lipid binding. It is unclear how this process relates to fast gating or if the intracellular and extracellular regions of the protein are coupled. Here, we examine the structural details of KirBac1.1 reconstituted into both POPC and an activating lipid mixture of 3:2 POPC:POPG (wt/wt). KirBac1.1 is a prokaryotic Kir channel that shares homology with human Kir channels. We establish that KirBac1.1 is in a constitutively active state in POPC:POPG bilayers through the use of real-time fluorescence quenching assays and Förster resonance energy transfer (FRET) distance measurements. Multidimensional solid-state NMR (SSNMR) spectroscopy experiments reveal two different conformers within the transmembrane regions of the protein in this activating lipid environment, which are distinct from the conformation of the channel in POPC bilayers. The differences between these three distinct channel states highlight conformational changes associated with an open activation gate and suggest a unique allosteric pathway that ties the selectivity filter to the activation gate through interactions between both transmembrane helices, the turret, selectivity filter loop, and the pore helix. We also identify specific residues involved in this conformational exchange that are highly conserved among human Kir channels.
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23
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Wright PD, McCoull D, Walsh Y, Large JM, Hadrys BW, Gaurilcikaite E, Byrom L, Veale EL, Jerman J, Mathie A. Pranlukast is a novel small molecule activator of the two-pore domain potassium channel TREK2. Biochem Biophys Res Commun 2019; 520:35-40. [DOI: 10.1016/j.bbrc.2019.09.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Accepted: 09/21/2019] [Indexed: 11/29/2022]
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24
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Şterbuleac D. Molecular determinants of chemical modulation of two-pore domain potassium channels. Chem Biol Drug Des 2019; 94:1596-1614. [PMID: 31124599 DOI: 10.1111/cbdd.13571] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Revised: 04/29/2019] [Accepted: 05/05/2019] [Indexed: 12/16/2022]
Abstract
The K+ ion channels comprising the two-pore domain (K2P) family have specific biophysical roles in generating the critical regulatory K+ current. Ion flow through K2P channels and, implicitly, channel regulation is mediated by diverse metabolic and physical inputs such as mechanical stimulation, interaction with lipids or endogenous regulators, intra- or extracellular pH, and phosphorylation, while their function can be finely tuned by chemical compounds. In the latter category, some drug-channel interactions can lead to side effects or have clinical action, while identifying novel chemical modulators of K2Ps is an area of intense research. Due to their cellular and therapeutic importance, much attention was turned to these channels in recent years and several experimental approaches have pinpointed the molecular determinants of K2P chemical modulation. Given their unique structural features and properties, chemical modulators act on K2P channels in multiple and diverse ways. In this review, the particularities of K2P modulation by chemical compounds, such as binding modality, affinity, or position, are identified, synthesized, and linked to structural and functional properties in order to refer to how activators and blockers modify channel function and vice versa, focusing on specificity related to protein structure (and its modification) and cross-linking information among different subfamilies.
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Affiliation(s)
- Daniel Şterbuleac
- Doctoral School of Biology, Faculty of Biology, "Alexandru Ioan Cuza" University of Iasi, Iasi, Romania
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25
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Kawasaki K, Suzuki Y, Yamamura H, Imaizumi Y. Development of a Novel Cell-Based Assay System for High-Throughput Screening of Compounds Acting on Background Two-Pore Domain K + Channels. SLAS DISCOVERY 2019; 24:641-652. [PMID: 30802418 DOI: 10.1177/2472555219829745] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Two-pore domain K+ (K2P) channels are thought to be druggable targets. However, only a few agents specific for K2P channels have been identified, presumably due to the lack of an efficient screening system. To develop a new high-throughput screening (HTS) system targeting these channels, we have established a HEK293-based "test cell" expressing a mutated Na+ channel (Nav1.5) with markedly slowed inactivation, as well as a K+ channel (Kir2.1) that sets the membrane potential quite negative, close to K+ equilibrium potential. We found in this system that Kir2.1 block by 100 μM Ba2+ application consistently elicited a large depolarization like a long-lasting action potential. This maneuver resulted in cell death, presumably due to the sustained Na+ influx. When either the TWIK-related acid-sensitive K+ (TASK)-1 or TASK-3 channel was expressed in the test cells, Ba2+-induced cell death was markedly weakened. Stronger activation of TASK-1 by extracellular acidification further decreased the cell death. In contrast, the presence of K2P channel blockers enhanced cell death. IC50 values for TASK-1 and/or TASK-3 blockers acquired by measurements of relative cell viability were comparable to those obtained using patch-clamp recordings. Both blockers and openers of K2P channels can be accurately assessed with high efficiency and throughput by this novel HTS system.
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Affiliation(s)
- Keisuke Kawasaki
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Yoshiaki Suzuki
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Hisao Yamamura
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan
| | - Yuji Imaizumi
- 1 Department of Molecular & Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, Japan.,2 Department of Research and Development, ChanneloSearch Technology Co., Ltd., Nagoya, Japan
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Lamas JA, Fernández-Fernández D. Tandem pore TWIK-related potassium channels and neuroprotection. Neural Regen Res 2019; 14:1293-1308. [PMID: 30964046 PMCID: PMC6524494 DOI: 10.4103/1673-5374.253506] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
TWIK-related potassium channels (TREK) belong to a subfamily of the two-pore domain potassium channels family with three members, TREK1, TREK2 and TWIK-related arachidonic acid-activated potassium channels. The two-pore domain potassium channels is the last big family of channels being discovered, therefore it is not surprising that most of the information we know about TREK channels predominantly comes from the study of heterologously expressed channels. Notwithstanding, in this review we pay special attention to the limited amount of information available on native TREK-like channels and real neurons in relation to neuroprotection. Mainly we focus on the role of free fatty acids, lysophospholipids and other neuroprotective agents like riluzole in the modulation of TREK channels, emphasizing on how important this modulation may be for the development of new therapies against neuropathic pain, depression, schizophrenia, epilepsy, ischemia and cardiac complications.
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Affiliation(s)
- J Antonio Lamas
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
| | - Diego Fernández-Fernández
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
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27
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Pope L, Arrigoni C, Lou H, Bryant C, Gallardo-Godoy A, Renslo AR, Minor DL. Protein and Chemical Determinants of BL-1249 Action and Selectivity for K 2P Channels. ACS Chem Neurosci 2018; 9:3153-3165. [PMID: 30089357 PMCID: PMC6302903 DOI: 10.1021/acschemneuro.8b00337] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
K2P potassium channels generate leak currents that stabilize the resting membrane potential of excitable cells. Various K2P channels are implicated in pain, ischemia, depression, migraine, and anesthetic responses, making this family an attractive target for small molecule modulator development efforts. BL-1249, a compound from the fenamate class of nonsteroidal anti-inflammatory drugs is known to activate K2P2.1(TREK-1), the founding member of the thermo- and mechanosensitive TREK subfamily; however, its mechanism of action and effects on other K2P channels are not well-defined. Here, we demonstrate that BL-1249 extracellular application activates all TREK subfamily members but has no effect on other K2P subfamilies. Patch clamp experiments demonstrate that, similar to the diverse range of other chemical and physical TREK subfamily gating cues, BL-1249 stimulates the selectivity filter "C-type" gate that controls K2P function. BL-1249 displays selectivity among the TREK subfamily, activating K2P2.1(TREK-1) and K2P10.1(TREK-2) ∼10-fold more potently than K2P4.1(TRAAK). Investigation of mutants and K2P2.1(TREK-1)/K2P4.1(TRAAK) chimeras highlight the key roles of the C-terminal tail in BL-1249 action and identify the M2/M3 transmembrane helix interface as a key site of BL-1249 selectivity. Synthesis and characterization of a set of BL-1249 analogs demonstrates that both the tetrazole and opposing tetralin moieties are critical for function, whereas the conformational mobility between the two ring systems impacts selectivity. Together, our findings underscore the landscape of modes by which small molecules can affect K2P channels and provide crucial information for the development of better and more selective K2P modulators of the TREK subfamily.
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Affiliation(s)
| | | | | | | | | | | | - Daniel L. Minor
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 United States
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Nedumaran B, Pineda RH, Rudra P, Lee S, Malykhina AP. Association of genetic polymorphisms in the pore domains of mechano-gated TREK-1 channel with overactive lower urinary tract symptoms in humans. Neurourol Urodyn 2018; 38:144-150. [PMID: 30350878 DOI: 10.1002/nau.23862] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 09/03/2018] [Indexed: 12/12/2022]
Abstract
AIMS Mechanosensitivity of the urinary bladder is regulated by many factors including mechano-gated two-pore domain (K2 P, KCNK) potassium channels. TWIK-related K+ channel, TREK-1, is a predominantly expressed member of K2 P channel family in the human detrusor, and its expression and function are diminished in patients with overactive lower urinary tract symptoms (LUTS). The changes in channel activity may result from spontaneously occurring gene mutations. The aim of this study was to compare single nucleotide polymorphisms (SNPs) in TREK-1 channel between patients with LUTS and healthy donors. METHODS Six SNPs (rs370266806, rs373919966, rs758937019, rs769301539, rs772497750, and rs775158737) in two pore domains of human TREK-1 gene were analyzed using TaqMan SNP genotyping assay with manufacturer-designed primers and allele-specific probes. The screening was done in control bladders and detrusor specimens from patients with overactive LUTS. Statistical analyses were performed using R, Fisher's exact test and Hardy-Weinberg Equilibrium. RESULTS Six SNPs in two pore domains of the human TREK-1 gene were analyzed in human bladder specimens. The frequencies of rs758937019-CT genotype (P = 0.0016) and rs758937019-T allele (P = 0.0022) were significantly higher in the group with overactive LUTS. There was no significant association of rs775158737-GA genotype and rs775158737-A allele with the overactive LUTS, though they were present only in the overactive LUTS group. CONCLUSIONS Our results provide evidence that altered expression and function of TREK-1 channel in patients with overactive LUTS could be due to genetic polymorphisms in the pore domains of TREK-1 channel (rs758937019).
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Affiliation(s)
- Balachandar Nedumaran
- Division of Urology, Department of Surgery, University of Colorado Denver, Aurora, Colorado.,Division of Cardiothoracic Surgery, Department of Surgery, University of Colorado Denver, Aurora, Colorado
| | - Ricardo H Pineda
- Division of Urology, Department of Surgery, University of Colorado Denver, Aurora, Colorado
| | - Pratyaydipta Rudra
- Department of Biostatistics and Informatics, Colorado School of Public Health, University of Colorado Denver, Aurora, Colorado
| | - Sanghee Lee
- Department of Urology, University of California San Diego, La Jolla, California
| | - Anna P Malykhina
- Division of Urology, Department of Surgery, University of Colorado Denver, Aurora, Colorado
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Viatchenko-Karpinski V, Ling J, Gu JG. Characterization of temperature-sensitive leak K + currents and expression of TRAAK, TREK-1, and TREK2 channels in dorsal root ganglion neurons of rats. Mol Brain 2018; 11:40. [PMID: 29980241 PMCID: PMC6035395 DOI: 10.1186/s13041-018-0384-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 06/27/2018] [Indexed: 11/10/2022] Open
Abstract
Leak K+ currents are mediated by two-pore domain K+ (K2P) channels and are involved in controlling neuronal excitability. Of 15 members of K2P channels cloned so far, TRAAK, TREK-1, and TREK-2 are temperature sensitive. In the present study, we show that strong immunoreactivity of TRAAK, TREK-1 and TREK-2 channels was present mainly in small-sized dorsal root ganglion (DRG) neurons of rats. The percentages of neurons with strong immunoreactivity of TRAAK, TREK-1 and TREK-2 channels were 27, 23, and 20%, respectively. Patch-clamp recordings were performed to examine isolated leak K+ currents on acutely dissociated small-sized rat DRG neurons at room temperature of 22 °C, cool temperature of 14 °C and warm temperature of 30 °C. In majority of small-sized DRG neurons recorded (76%), large leak K+ currents were observed at 22 °C and were inhibited at 14 °C and potentiated at 30 °C, suggesting the presence of temperature-sensitive K2P channels in these neurons. In a small population (18%) of small-sized DRG neurons, cool temperature of 14 °C evoked a conductance which was consistent with TRPM8 channel activation in cold-sensing DRG neurons. In these DRG neurons, leak K+ currents were very small at 22 °C and were not potentiated at 30 °C, suggesting that few temperature-sensitive K2P channels was present in cold-sensing DRG neurons. For DRG neurons with temperature-sensitive leak K+ currents, riluzole, norfluoxetine and prostaglandin F2α (PGE2α) inhibited the leak K+ currents at both 30 °C and 22 °C degree, and did not have inhibitory effects at 14 °C. Collectively, the observed temperature-sensitive leak K+ currents are consistent with the expression of temperature-sensitive K2P channels in small-sized DRG neurons.
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Affiliation(s)
- Viacheslav Viatchenko-Karpinski
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19TH Street South, BMR II 210, Birmingham, AL, 35294, USA
| | - Jennifer Ling
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19TH Street South, BMR II 210, Birmingham, AL, 35294, USA
| | - Jianguo G Gu
- Department of Anesthesiology and Perioperative Medicine, University of Alabama at Birmingham, 901 19TH Street South, BMR II 210, Birmingham, AL, 35294, USA.
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30
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Loucif AJC, Saintot P, Liu J, Antonio BM, Zellmer SG, Yoger K, Veale EL, Wilbrey A, Omoto K, Cao L, Gutteridge A, Castle NA, Stevens EB, Mathie A. GI-530159, a novel, selective, mechanosensitive two-pore-domain potassium (K 2P ) channel opener, reduces rat dorsal root ganglion neuron excitability. Br J Pharmacol 2018; 175:2272-2283. [PMID: 29150838 PMCID: PMC5980259 DOI: 10.1111/bph.14098] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/09/2017] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND AND PURPOSE TREK two-pore-domain potassium (K2P ) channels play a critical role in regulating the excitability of somatosensory nociceptive neurons and are important mediators of pain perception. An understanding of the roles of TREK channels in pain perception and, indeed, in other pathophysiological conditions, has been severely hampered by the lack of potent and/or selective activators and inhibitors. In this study, we describe a new, selective opener of TREK channels, GI-530159. EXPERIMENTAL APPROACH The effect of GI-530159 on TREK channels was demonstrated using 86 Rb efflux assays, whole-cell and single-channel patch-clamp recordings from recombinant TREK channels. The expression of K2P 2.1 (TREK1), K2P 10.1 (TREK2) and K2P 4.1 (TRAAK) channels was determined using transcriptome analysis from single dorsal root ganglion (DRG) cells. Current-clamp recordings from cultured rat DRG neurons were used to measure the effect of GI-530159 on neuronal excitability. KEY RESULTS For recombinant human TREK1 channels, GI-530159 had similar low EC50 values in Rb efflux experiments and electrophysiological recordings. It activated TREK2 channels, but it had no detectable action on TRAAK channels nor any significant effect on other K channels tested. Current-clamp recordings from cultured rat DRG neurones showed that application of GI-530159 at 1 μM resulted in a significant reduction in firing frequency and a small hyperpolarization of resting membrane potential. CONCLUSIONS AND IMPLICATIONS This study provides pharmacological evidence for the presence of mechanosensitive TREK K2P channels in sensory neurones and suggests that development of selective K2P channel openers like GI-530159 could aid in the development of novel analgesic agents. LINKED ARTICLES This article is part of a themed section on Recent Advances in Targeting Ion Channels to Treat Chronic Pain. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.12/issuetoc.
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Affiliation(s)
| | | | | | | | | | | | - Emma L Veale
- Medway School of PharmacyUniversity of KentChatham MaritimeKentUK
| | | | | | | | | | | | | | - Alistair Mathie
- Medway School of PharmacyUniversity of KentChatham MaritimeKentUK
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31
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Wright PD, Veale EL, McCoull D, Tickle DC, Large JM, Ococks E, Gothard G, Kettleborough C, Mathie A, Jerman J. Terbinafine is a novel and selective activator of the two-pore domain potassium channel TASK3. Biochem Biophys Res Commun 2017; 493:444-450. [DOI: 10.1016/j.bbrc.2017.09.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 09/01/2017] [Indexed: 12/12/2022]
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32
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Jiménez-Vargas JM, Possani LD, Luna-Ramírez K. Arthropod toxins acting on neuronal potassium channels. Neuropharmacology 2017; 127:139-160. [PMID: 28941737 DOI: 10.1016/j.neuropharm.2017.09.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 09/13/2017] [Accepted: 09/15/2017] [Indexed: 01/01/2023]
Abstract
Arthropod venoms are a rich mixture of biologically active compounds exerting different physiological actions across diverse phyla and affecting multiple organ systems including the central nervous system. Venom compounds can inhibit or activate ion channels, receptors and transporters with high specificity and affinity providing essential insights into ion channel function. In this review, we focus on arthropod toxins (scorpions, spiders, bees and centipedes) acting on neuronal potassium channels. A brief description of the K+ channels classification and structure is included and a compendium of neuronal K+ channels and the arthropod toxins that modify them have been listed. This article is part of the Special Issue entitled 'Venom-derived Peptides as Pharmacological Tools.'
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Affiliation(s)
- Juana María Jiménez-Vargas
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Lourival D Possani
- Departamento de Medicina Molecular y Bioprocesos, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Avenida Universidad, 2001, Colonia Chamilpa, Apartado Postal 510-3, Cuernavaca 62210, Mexico
| | - Karen Luna-Ramírez
- Illawarra Health and Medical Research Institute, University of Wollongong, Northfields Avenue, Wollongong, NSW 2522, Australia.
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Vierra NC, Dadi PK, Milian SC, Dickerson MT, Jordan KL, Gilon P, Jacobson DA. TALK-1 channels control β cell endoplasmic reticulum Ca 2+ homeostasis. Sci Signal 2017; 10:eaan2883. [PMID: 28928238 PMCID: PMC5672804 DOI: 10.1126/scisignal.aan2883] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Ca2+ handling by the endoplasmic reticulum (ER) serves critical roles in controlling pancreatic β cell function and becomes perturbed during the pathogenesis of diabetes. ER Ca2+ homeostasis is determined by ion movements across the ER membrane, including K+ flux through K+ channels. We demonstrated that K+ flux through ER-localized TALK-1 channels facilitated Ca2+ release from the ER in mouse and human β cells. We found that β cells from mice lacking TALK-1 exhibited reduced basal cytosolic Ca2+ and increased ER Ca2+ concentrations, suggesting reduced ER Ca2+ leak. These changes in Ca2+ homeostasis were presumably due to TALK-1-mediated ER K+ flux, because we recorded K+ currents mediated by functional TALK-1 channels on the nuclear membrane, which is continuous with the ER. Moreover, overexpression of K+-impermeable TALK-1 channels in HEK293 cells did not reduce ER Ca2+ stores. Reduced ER Ca2+ content in β cells is associated with ER stress and islet dysfunction in diabetes, and islets from TALK-1-deficient mice fed a high-fat diet showed reduced signs of ER stress, suggesting that TALK-1 activity exacerbated ER stress. Our data establish TALK-1 channels as key regulators of β cell ER Ca2+ and suggest that TALK-1 may be a therapeutic target to reduce ER Ca2+ handling defects in β cells during the pathogenesis of diabetes.
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Affiliation(s)
- Nicholas C Vierra
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Prasanna K Dadi
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Sarah C Milian
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Matthew T Dickerson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Kelli L Jordan
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Patrick Gilon
- Pôle d'endocrinologie, diabète et nutrition, Institut de recherche expérimentale et clinique, Université catholique de Louvain, Brussels 1200, Belgium
| | - David A Jacobson
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
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