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Ribeuz HL, Willer ASM, Chevalier B, Sancho M, Masson B, Eyries M, Jung V, Guerrera IC, Dutheil M, Jekmek KE, Laubry L, Carpentier G, Perez-Vizcaino F, Tu L, Guignabert C, Chaumais MC, Péchoux C, Humbert M, Hinzpeter A, Mercier O, Capuano V, Montani D, Antigny F. Role of KCNK3 Dysfunction in Dasatinib-associated Pulmonary Arterial Hypertension and Endothelial Cell Dysfunction. Am J Respir Cell Mol Biol 2024; 71:95-109. [PMID: 38546978 DOI: 10.1165/rcmb.2023-0185oc] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 03/27/2024] [Indexed: 07/02/2024] Open
Abstract
Pulmonary arterial (PA) hypertension (PAH) is a severe cardiopulmonary disease that may be triggered by exposure to drugs such as dasatinib or facilitated by genetic predispositions. The incidence of dasatinib-associated PAH is estimated at 0.45%, suggesting individual predispositions. The mechanisms of dasatinib-associated PAH are still incomplete. We discovered a KCNK3 gene (Potassium channel subfamily K member 3; coding for outward K+ channel) variant in a patient with dasatinib-associated PAH and investigated the impact of this variant on KCNK3 function. Additionally, we assessed the effects of dasatinib exposure on KCNK3 expression. In control human PA smooth muscle cells (hPASMCs) and human pulmonary endothelial cells (hPECs), we evaluated the consequences of KCNK3 knockdown on cell migration, mitochondrial membrane potential, ATP production, and in vitro tube formation. Using mass spectrometry, we determined the KCNK3 interactome. Patch-clamp experiments revealed that the KCNK3 variant represents a loss-of-function variant. Dasatinib contributed to PA constriction by decreasing KCNK3 function and expression. In control hPASMCs, KCNK3 knockdown promotes mitochondrial membrane depolarization and glycolytic shift. Dasatinib exposure or KCNK3 knockdown reduced the number of caveolae in hPECs. Moreover, KCNK3 knockdown in control hPECs reduced migration, proliferation, and in vitro tubulogenesis. Using proximity labeling and mass spectrometry, we identified the KCNK3 interactome, revealing that KCNK3 interacts with various proteins across different cellular compartments. We identified a novel pathogenic variant in KCNK3 and showed that dasatinib downregulates KCNK3, emphasizing the relationship between dasatinib-associated PAH and KCNK3 dysfunction. We demonstrated that a loss of KCNK3-dependent signaling contributes to endothelial dysfunction in PAH and glycolytic switch of hPASMCs.
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Affiliation(s)
- Hélène Le Ribeuz
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Anaïs Saint-Martin Willer
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Benoit Chevalier
- Paris Cité University, CNRS, INSERM, Institut Necker Enfants Malades-INEM, Paris, France
| | - Maria Sancho
- Department of Physiology and
- Department of Pharmacology, University of Vermont, Burlington, Vermont
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
| | - Bastien Masson
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Mélanie Eyries
- Genetics Department, Pitié-Salpêtrière Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Vincent Jung
- INSERM US24/CNRS UAR3633, Proteomic Platform Necker, Université Paris Cité-Federative Research Structure Necker, Paris, France
| | - Ida Chiara Guerrera
- INSERM US24/CNRS UAR3633, Proteomic Platform Necker, Université Paris Cité-Federative Research Structure Necker, Paris, France
| | - Mary Dutheil
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Kristelle El Jekmek
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Loann Laubry
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Gilles Carpentier
- Gly-CRRET Research Unit 4397, Paris-Est Créteil University, Créteil, France
| | - Francisco Perez-Vizcaino
- Department of Pharmacology and Toxicology, Faculty of Medicine, University Complutense of Madrid, Madrid, Spain
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain
- Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Ly Tu
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Christophe Guignabert
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Marie-Camille Chaumais
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
- Paris-Saclay University, Faculty of Pharmacy, Orsay, France
- Department of Respiratory and Intensive Care Medicine, Pulmonary Hypertension National Referral Center, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Christine Péchoux
- Paris-Saclay University, INRAE, AgroparisTech, GABI, Jouy-en-Josas, France
| | - Marc Humbert
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
- Department of Respiratory and Intensive Care Medicine, Pulmonary Hypertension National Referral Center, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Alexandre Hinzpeter
- Paris Cité University, CNRS, INSERM, Institut Necker Enfants Malades-INEM, Paris, France
| | - Olaf Mercier
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
- Department of Thoracic and Vascular Surgery and Heart-Lung Transplantation, Groupe Hospitalier Paris Saint-Joseph-Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - Véronique Capuano
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
| | - David Montani
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
- Department of Respiratory and Intensive Care Medicine, Pulmonary Hypertension National Referral Center, Bicêtre Hospital, Le Kremlin-Bicêtre, France
| | - Fabrice Antigny
- Paris-Saclay University, Faculty of Medecine, Le Kremlin-Bicêtre, France
- INSERM UMR_S 999 Pulmonary Hypertension: Pathophysiology and Novel Therapies, Marie Lannelongue Hospital, Le Plessis-Robinson, France
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Wiedmann F, Paasche A, Nietfeld J, Kraft M, Meyer AL, Warnecke G, Karck M, Frey N, Schmidt C. Activation of neurokinin-III receptors modulates human atrial TASK-1 currents. J Mol Cell Cardiol 2023; 184:26-36. [PMID: 37793594 DOI: 10.1016/j.yjmcc.2023.09.010] [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: 05/30/2023] [Revised: 09/26/2023] [Accepted: 09/30/2023] [Indexed: 10/06/2023]
Abstract
RATIONALE The neurokinin-III receptor was recently shown to regulate atrial cardiomyocyte excitability by inhibiting atrial background potassium currents. TASK-1 (hK2P3.1) two-pore-domain potassium channels, which are expressed atrial-specifically in the human heart, contribute significantly to atrial background potassium currents. As TASK-1 channels are regulated by a variety of intracellular signalling cascades, they represent a promising candidate for mediating the electrophysiological effects of the Gq-coupled neurokinin-III receptor. OBJECTIVE To investigate whether TASK-1 channels mediate the neurokinin-III receptor activation induced effects on atrial electrophysiology. METHODS AND RESULTS In Xenopus laevis oocytes, heterologously expressing neurokinin-III receptor and TASK-1, administration of the endogenous neurokinin-III receptor ligands substance P or neurokinin B resulted in a strong TASK-1 current inhibition. This could be reproduced by application of the high affinity neurokinin-III receptor agonist senktide. Moreover, preincubation with the neurokinin-III receptor antagonist osanetant blunted the effect of senktide. Mutagenesis studies employing TASK-1 channel constructs which lack either protein kinase C (PKC) phosphorylation sites or the domain which is regulating the diacyl glycerol (DAG) sensitivity domain of TASK-1 revealed a protein kinase C independent mechanism of TASK-1 current inhibition: upon neurokinin-III receptor activation TASK-1 channels are blocked in a DAG-dependent fashion. Finally, effects of senktide on atrial TASK-1 currents could be reproduced in patch-clamp measurements, performed on isolated human atrial cardiomyocytes. CONCLUSIONS Heterologously expressed human TASK-1 channels are inhibited by neurokinin-III receptor activation in a DAG dependent fashion. Patch-clamp measurements, performed on human atrial cardiomyocytes suggest that the atrial-specific effects of neurokinin-III receptor activation on cardiac excitability are predominantly mediated via TASK-1 currents.
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Affiliation(s)
- Felix Wiedmann
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg /Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Amelie Paasche
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg /Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Jendrik Nietfeld
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany
| | - Manuel Kraft
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg /Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Anna L Meyer
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Gregor Warnecke
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Matthias Karck
- Department of Cardiac Surgery, University Hospital Heidelberg, Heidelberg, Germany
| | - Norbert Frey
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg /Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany
| | - Constanze Schmidt
- Department of Cardiology, University Hospital Heidelberg, Heidelberg, Germany; DZHK (German Center for Cardiovascular Research), Partner Site Heidelberg /Mannheim, University of Heidelberg, Heidelberg, Germany; HCR, Heidelberg Center for Heart Rhythm Disorders, University Hospital Heidelberg, Heidelberg, Germany.
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Zhen H, Zheng M, Song Q, Liu H, Yuan Z, Cao Z, Zhao B. U73122 and m-3M3FBS Regulate the GABAergic Neuron Regeneration via PLCβ in Planarian Dugesia japonica. NEUROCHEM J+ 2021. [DOI: 10.1134/s1819712421040188] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Singh S, Agarwal P, Ravichandiran V. Two-Pore Domain Potassium Channel in Neurological Disorders. J Membr Biol 2021; 254:367-380. [PMID: 34169340 DOI: 10.1007/s00232-021-00189-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/26/2021] [Indexed: 01/10/2023]
Abstract
K2P channel is the leaky potassium channel that is critical to keep up the negative resting membrane potential for legitimate electrical conductivity of the excitable tissues. Recently, many substances and medication elements are discovered that could either straightforwardly or in a roundabout way influence the 15 distinctive K+ ion channels including TWIK, TREK, TASK, TALK, THIK, and TRESK. Opening and shutting of these channels or any adjustment in their conduct is thought to alter the pathophysiological condition of CNS. There is no document available till now to explain in detail about the molecular mechanism of agents acting on K2P channel. Accordingly, in this review we cover the current research and mechanism of action of these channels, we have also tried to mention the detailed effect of drugs and how the channel behavior changes by focusing on recent advances regarding activation and modulation of ion channels.
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Affiliation(s)
- Sanjiv Singh
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Export Promotions Industrial Park (EPIP), Industrial Area, Hajipur, District, Vaishali, 844102, Bihar, India.
| | - Punita Agarwal
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Export Promotions Industrial Park (EPIP), Industrial Area, Hajipur, District, Vaishali, 844102, Bihar, India
| | - V Ravichandiran
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER), Export Promotions Industrial Park (EPIP), Industrial Area, Hajipur, District, Vaishali, 844102, Bihar, India
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McCarty MF. Nutraceutical, Dietary, and Lifestyle Options for Prevention and Treatment of Ventricular Hypertrophy and Heart Failure. Int J Mol Sci 2021; 22:ijms22073321. [PMID: 33805039 PMCID: PMC8037104 DOI: 10.3390/ijms22073321] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/12/2022] Open
Abstract
Although well documented drug therapies are available for the management of ventricular hypertrophy (VH) and heart failure (HF), most patients nonetheless experience a downhill course, and further therapeutic measures are needed. Nutraceutical, dietary, and lifestyle measures may have particular merit in this regard, as they are currently available, relatively safe and inexpensive, and can lend themselves to primary prevention as well. A consideration of the pathogenic mechanisms underlying the VH/HF syndrome suggests that measures which control oxidative and endoplasmic reticulum (ER) stress, that support effective nitric oxide and hydrogen sulfide bioactivity, that prevent a reduction in cardiomyocyte pH, and that boost the production of protective hormones, such as fibroblast growth factor 21 (FGF21), while suppressing fibroblast growth factor 23 (FGF23) and marinobufagenin, may have utility for preventing and controlling this syndrome. Agents considered in this essay include phycocyanobilin, N-acetylcysteine, lipoic acid, ferulic acid, zinc, selenium, ubiquinol, astaxanthin, melatonin, tauroursodeoxycholic acid, berberine, citrulline, high-dose folate, cocoa flavanols, hawthorn extract, dietary nitrate, high-dose biotin, soy isoflavones, taurine, carnitine, magnesium orotate, EPA-rich fish oil, glycine, and copper. The potential advantages of whole-food plant-based diets, moderation in salt intake, avoidance of phosphate additives, and regular exercise training and sauna sessions are also discussed. There should be considerable scope for the development of functional foods and supplements which make it more convenient and affordable for patients to consume complementary combinations of the agents discussed here. Research Strategy: Key word searching of PubMed was employed to locate the research papers whose findings are cited in this essay.
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Affiliation(s)
- Mark F McCarty
- Catalytic Longevity Foundation, 811 B Nahant Ct., San Diego, CA 92109, USA
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6
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TASK channels: channelopathies, trafficking, and receptor-mediated inhibition. Pflugers Arch 2020; 472:911-922. [DOI: 10.1007/s00424-020-02403-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/08/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023]
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7
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Jones SA, Walton RD, Morton M, Lancaster MK. K 2p 3.1 protein is expressed as a transmural gradient across the rat left ventricular free wall. J Cardiovasc Electrophysiol 2018; 30:383-391. [PMID: 30516300 PMCID: PMC6446730 DOI: 10.1111/jce.13805] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 11/08/2018] [Accepted: 11/15/2018] [Indexed: 12/25/2022]
Abstract
Introduction K2p3.1, also known as TASK‐1, is a twin‐pore acid‐sensitive repolarizing K+ channel, responsible for a background potassium current that significantly contributes to setting the resting membrane potential of cardiac myocytes. Inhibition of IK2p3.1 alters cardiac repolarization and is proarrhythmogenic. In this study, we have examined the expression of K2p3.1 and function of this channel in tissue and myocytes from across the left ventricular free wall. Methods and Results Using fluorescence immunocytochemistry, the expression of K2p3.1 protein in myocytes from the subendocardial region was found to be twice (205% ± 13.5%) that found in myocytes from the subepicardial region of the left ventricle (100% ± 5.3%). The left ventricular free wall exhibited a marked transmural gradient of K2p3.1 protein expression. Western blot analysis confirmed significantly higher K2p3.1 protein expression in subendocardial tissue (156% ± 2.5%) than subepicardial tissue (100% ± 5.0%). However, there was no difference in K2p3.1 messenger RNA expression. Whole‐cell patch clamp identified IK2p3.1 current density to be significantly greater in myocytes isolated from the subendocardium (7.66 ± 0.53 pA/pF) compared with those from the subepicardium (3.47 ± 0.74 pA/pF). Conclusions This is the first study to identify a transmural gradient of K2p3.1 in the left ventricle. This gradient has implications for understanding ventricular arrhythmogenesis under conditions of ischemia but also in response to other modulatory factors, such as adrenergic stimulation and the presence of anesthetics that inhibits or activates this channel.
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Affiliation(s)
- Sandra A Jones
- Department of Biomedical Sciences, Department Faculty of Health Sciences, University of Hull, Hull, UK
| | - Richard D Walton
- Centre de Recherche Cardio-Thoracique de Bordeaux U1045, Université de Bordeaux, Bordeaux, France.,Inserm, Centre de Recherche Cardio-Thoracique de Bordeaux, Bordeaux, France.,L'Institut de Rythmologie et Modélisation Cardiaque LIRYC, Fondation Bordeaux Université, Bordeaux, France
| | | | - Matthew K Lancaster
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, UK
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Cunningham KP, Holden RG, Escribano-Subias PM, Cogolludo A, Veale EL, Mathie A. Characterization and regulation of wild-type and mutant TASK-1 two pore domain potassium channels indicated in pulmonary arterial hypertension. J Physiol 2018; 597:1087-1101. [PMID: 30365877 PMCID: PMC6376074 DOI: 10.1113/jp277275] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 10/24/2018] [Indexed: 12/22/2022] Open
Abstract
Key points The TASK‐1 channel gene (KCNK3) has been identified as a possible disease‐causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK‐1 channels, seen in PAH patients, have a substantially reduced current compared to wild‐type TASK‐1 channels. These mutated TASK‐1 channels are located at the plasma membrane to the same degree as wild‐type TASK‐1 channels. ONO‐RS‐082 and alkaline pH 8.4 both activate TASK‐1 channels but do not recover current through mutant TASK‐1 channels. We show that the guanylate cyclase activator, riociguat, a novel treatment for PAH, enhances current through TASK‐1 channels but does not recover current through mutant TASK‐1 channels.
Abstract Pulmonary arterial hypertension (PAH) affects ∼15–50 people per million. KCNK3, the gene that encodes the two pore domain potassium channel TASK‐1 (K2P3.1), has been identified as a possible disease‐causing gene in heritable PAH. Recently, two new mutations have been identified in KCNK3 in PAH patients: G106R and L214R. The present study aimed to characterize the functional properties and regulation of wild‐type (WT) and mutated TASK‐1 channels and determine how these might contribute to PAH and its treatment. Currents through WT and mutated human TASK‐1 channels transiently expressed in tsA201 cells were measured using whole‐cell patch clamp electrophysiology. Localization of fluorescence‐tagged channels was visualized using confocal microscopy and quantified with in‐cell and on‐cell westerns. G106R or L214R mutated channels were located at the plasma membrane to the same degree as WT channels; however, their current was markedly reduced compared to WT TASK‐1 channels. Functional current through these mutated channels could not be restored using activators of WT TASK‐1 channels (pH 8.4, ONO‐RS‐082). The guanylate cyclase activator, riociguat, enhanced current through WT TASK‐1 channels; however, similar to the other activators investigated, riociguat did not have any effect on current through mutated TASK‐1 channels. Thus, novel mutations in TASK‐1 seen in PAH substantially alter the functional properties of these channels. Current through these channels could not be restored by activators of TASK‐1 channels. Riociguat enhancement of current through TASK‐1 channels could contribute to its therapeutic benefit in the treatment of PAH. The TASK‐1 channel gene (KCNK3) has been identified as a possible disease‐causing gene in heritable pulmonary arterial hypertension (PAH). In the present study, we show that novel mutated TASK‐1 channels, seen in PAH patients, have a substantially reduced current compared to wild‐type TASK‐1 channels. These mutated TASK‐1 channels are located at the plasma membrane to the same degree as wild‐type TASK‐1 channels. ONO‐RS‐082 and alkaline pH 8.4 both activate TASK‐1 channels but do not recover current through mutant TASK‐1 channels. We show that the guanylate cyclase activator, riociguat, a novel treatment for PAH, enhances current through TASK‐1 channels but does not recover current through mutant TASK‐1 channels.
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Affiliation(s)
- Kevin P Cunningham
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | - Robyn G Holden
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | | | - Angel Cogolludo
- Department of Pharmacology and Toxicology, School of Medicine, University Complutense of Madrid, Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Ciber Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent and University of Greenwich, Chatham Maritime, Kent, UK
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Wu D, Zhang Q, Yu Y, Zhang Y, Zhang M, Liu Q, Zhang E, Li S, Song G. Oleanolic Acid, a Novel Endothelin A Receptor Antagonist, Alleviated High Glucose-Induced Cardiomyocytes Injury. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2018. [DOI: 10.1142/s0192415x18500623 pmid: 30149760] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Endothelin-1 (ET-1) and its receptor endothelin A receptor (ET[Formula: see text] have been shown to be upregulated in a high glucose environment, which increase the incidence of diabetes-related heart failure. Our previous study demonstrated that oleanolic acid (OA), a natural compound found in Chinese herbs had ET-1 antagonistic effects. We aimed to verify whether OA could ameliorate diabetes mellitus (DM)-induced injury in cardiomyocytes by reducing the antagonistic effects of the ET-1 pathway. For the induction of high glucose-related injury in cardiomyocytes, neonatal rat ventricular cardiomyocytes (NRVMs) were subjected to culture medium containing 25[Formula: see text]mM of glucose. Natriuretic peptide B (BNP), mitochondrial membrane potential (MMP) and cell surface area were measured to evaluate the severity of NRVMs injury. mRNA expression of ET-1 and ETA was determined using quantitative PCR. Moreover, a Ca[Formula: see text] influx assay was used to evaluate potential ETA antagonistic effects. Molecular docking of OA and ETA was performed using the Sulflex-Dock program. Human induced pluripotent stem cell (iPS-C)-derived cardiomyocytes and real time cell analysis system (RTCA) were used to verify the effect of OA on the ET-1 pathway. High glucose levels increased the expression of BNP at both mRNA and protein levels in cardiomyocytes. Moreover, cell surface area and MMP were also elevated in a high glucose environment. High glucose-induced injury in NRVMs was not reversible by hypoglycemic therapy. In addition, ETA was upregulated by high glucose treatment and levels could not be reduced by hypoglycemic treatment. The Ca[Formula: see text] influx assay on ETA/HEK293 cells showed that OA had a partial ETA antagonistic effect. Molecular docking approaches showed that OA was docked into the active site of ETA. Furthermore, functionality tests based on iPS-C and RTCA demonstrated that treatment with OA could reverse ET-1-induced alternation of beating rates and amplitude. Thus, OA could reverse high glucose-induced BNP upregulation, and increased both the cell area and MMP in NRVMs. High glucose-induced irreversible ETA upregulation is a major reason of continuous diabetes-related injury in cardiomyocytes. Treatment with OA had a protective effect on high glucose-induced injury in cardiomyocytes through a partial ETA antagonistic role.
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Affiliation(s)
- Dewei Wu
- Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
- Department of Cardiology, Beijing Aerospace General Hospital, Beijing 100076, China
| | - Qiao Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Yangyang Yu
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Yuxin Zhang
- School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Minyu Zhang
- Institute of Chinese Materia Medica, Post-Doctoral Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qing Liu
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Erli Zhang
- Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Shiyou Li
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Guangyuan Song
- Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
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Wu D, Zhang Q, Yu Y, Zhang Y, Zhang M, Liu Q, Zhang E, Li S, Song G. Oleanolic Acid, a Novel Endothelin A Receptor Antagonist, Alleviated High Glucose-Induced Cardiomyocytes Injury. THE AMERICAN JOURNAL OF CHINESE MEDICINE 2018; 46:1187-1201. [PMID: 30149760 DOI: 10.1142/s0192415x18500623] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Endothelin-1 (ET-1) and its receptor endothelin A receptor (ET[Formula: see text] have been shown to be upregulated in a high glucose environment, which increase the incidence of diabetes-related heart failure. Our previous study demonstrated that oleanolic acid (OA), a natural compound found in Chinese herbs had ET-1 antagonistic effects. We aimed to verify whether OA could ameliorate diabetes mellitus (DM)-induced injury in cardiomyocytes by reducing the antagonistic effects of the ET-1 pathway. For the induction of high glucose-related injury in cardiomyocytes, neonatal rat ventricular cardiomyocytes (NRVMs) were subjected to culture medium containing 25[Formula: see text]mM of glucose. Natriuretic peptide B (BNP), mitochondrial membrane potential (MMP) and cell surface area were measured to evaluate the severity of NRVMs injury. mRNA expression of ET-1 and ETA was determined using quantitative PCR. Moreover, a Ca[Formula: see text] influx assay was used to evaluate potential ETA antagonistic effects. Molecular docking of OA and ETA was performed using the Sulflex-Dock program. Human induced pluripotent stem cell (iPS-C)-derived cardiomyocytes and real time cell analysis system (RTCA) were used to verify the effect of OA on the ET-1 pathway. High glucose levels increased the expression of BNP at both mRNA and protein levels in cardiomyocytes. Moreover, cell surface area and MMP were also elevated in a high glucose environment. High glucose-induced injury in NRVMs was not reversible by hypoglycemic therapy. In addition, ETA was upregulated by high glucose treatment and levels could not be reduced by hypoglycemic treatment. The Ca[Formula: see text] influx assay on ETA/HEK293 cells showed that OA had a partial ETA antagonistic effect. Molecular docking approaches showed that OA was docked into the active site of ETA. Furthermore, functionality tests based on iPS-C and RTCA demonstrated that treatment with OA could reverse ET-1-induced alternation of beating rates and amplitude. Thus, OA could reverse high glucose-induced BNP upregulation, and increased both the cell area and MMP in NRVMs. High glucose-induced irreversible ETA upregulation is a major reason of continuous diabetes-related injury in cardiomyocytes. Treatment with OA had a protective effect on high glucose-induced injury in cardiomyocytes through a partial ETA antagonistic role.
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Affiliation(s)
- Dewei Wu
- * Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China.,¶ Department of Cardiology, Beijing Aerospace General Hospital, Beijing 100076, China
| | - Qiao Zhang
- † School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Yangyang Yu
- † School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Yuxin Zhang
- † School of Chinese Materia Medica, Beijing University of Chinese Medicine, Beijing 100102, China
| | - Minyu Zhang
- ‡ Institute of Chinese Materia Medica, Post-Doctoral Research Center, China Academy of Chinese Medical Sciences, Beijing 100700, China.,§ Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Qing Liu
- § Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Erli Zhang
- * Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
| | - Shiyou Li
- § Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing 100101, China
| | - Guangyuan Song
- * Coronary Heart Disease Center, National Center for Cardiovascular Diseases and Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100037, China
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11
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Olschewski A, Veale EL, Nagy BM, Nagaraj C, Kwapiszewska G, Antigny F, Lambert M, Humbert M, Czirják G, Enyedi P, Mathie A. TASK-1 (KCNK3) channels in the lung: from cell biology to clinical implications. Eur Respir J 2017; 50:50/5/1700754. [PMID: 29122916 DOI: 10.1183/13993003.00754-2017] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 08/05/2017] [Indexed: 12/18/2022]
Abstract
TWIK-related acid-sensitive potassium channel 1 (TASK-1 encoded by KCNK3) belongs to the family of two-pore domain potassium channels. This gene subfamily is constitutively active at physiological resting membrane potentials in excitable cells, including smooth muscle cells, and has been particularly linked to the human pulmonary circulation. TASK-1 channels are sensitive to a wide array of physiological and pharmacological mediators that affect their activity such as unsaturated fatty acids, extracellular pH, hypoxia, anaesthetics and intracellular signalling pathways. Recent studies show that modulation of TASK-1 channels, either directly or indirectly by targeting their regulatory mechanisms, has the potential to control pulmonary arterial tone in humans. Furthermore, mutations in KCNK3 have been identified as a rare cause of both familial and idiopathic pulmonary arterial hypertension. This review summarises our current state of knowledge of the functional role of TASK-1 channels in the pulmonary circulation in health and disease, with special emphasis on current advancements in the field.
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Affiliation(s)
- Andrea Olschewski
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria .,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Emma L Veale
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, UK
| | - Bence M Nagy
- Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Chandran Nagaraj
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Grazyna Kwapiszewska
- Ludwig Boltzmann Institute for Lung Vascular Research Graz, Graz, Austria.,Institute of Physiology, Medical University of Graz, Graz, Austria
| | - Fabrice Antigny
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Mélanie Lambert
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Marc Humbert
- Univ. Paris-Sud, Faculté de Médecine, Kremlin-Bicêtre, France.,AP-HP, Centre de Référence de l'Hypertension Pulmonaire Sévère, Département Hospitalo-Universitaire (DHU) Thorax Innovation, Service de Pneumologie et Réanimation Respiratoire, Hôpital de Bicêtre, Le Kremlin-Bicêtre, France.,UMRS 999, INSERM and Univ. Paris-Sud, Laboratoire d'Excellence (LabEx) en Recherche sur le Médicament et l'Innovation Thérapeutique (LERMIT), Hôpital-Marie-Lannelongue, Le Plessis Robinson, France
| | - Gábor Czirják
- Dept of Physiology, Semmelweis University, Budapest, Hungary
| | - Péter Enyedi
- Dept of Physiology, Semmelweis University, Budapest, Hungary
| | - Alistair Mathie
- Medway School of Pharmacy, University of Kent, Central Avenue, Chatham Maritime, UK
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12
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Bohnen MS, Roman-Campos D, Terrenoire C, Jnani J, Sampson KJ, Chung WK, Kass RS. The Impact of Heterozygous KCNK3 Mutations Associated With Pulmonary Arterial Hypertension on Channel Function and Pharmacological Recovery. J Am Heart Assoc 2017; 6:JAHA.117.006465. [PMID: 28889099 PMCID: PMC5634293 DOI: 10.1161/jaha.117.006465] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND Heterozygous loss of function mutations in the KCNK3 gene cause hereditary pulmonary arterial hypertension (PAH). KCNK3 encodes an acid-sensitive potassium channel, which contributes to the resting potential of human pulmonary artery smooth muscle cells. KCNK3 is widely expressed in the body, and dimerizes with other KCNK3 subunits, or the closely related, acid-sensitive KCNK9 channel. METHODS AND RESULTS We engineered homomeric and heterodimeric mutant and nonmutant KCNK3 channels associated with PAH. Using whole-cell patch-clamp electrophysiology in human pulmonary artery smooth muscle and COS7 cell lines, we determined that homomeric and heterodimeric mutant channels in heterozygous KCNK3 conditions lead to mutation-specific severity of channel dysfunction. Both wildtype and mutant KCNK3 channels were activated by ONO-RS-082 (10 μmol/L), causing cell hyperpolarization. We observed robust gene expression of KCNK3 in healthy and familial PAH patient lungs, but no quantifiable expression of KCNK9, and demonstrated in functional studies that KCNK9 minimizes the impact of select KCNK3 mutations when the 2 channel subunits co-assemble. CONCLUSIONS Heterozygous KCNK3 mutations in PAH lead to variable loss of channel function via distinct mechanisms. Homomeric and heterodimeric mutant KCNK3 channels represent novel therapeutic substrates in PAH. Pharmacological and pH-dependent activation of wildtype and mutant KCNK3 channels in pulmonary artery smooth muscle cells leads to membrane hyperpolarization. Co-assembly of KCNK3 with KCNK9 subunits may provide protection against KCNK3 loss of function in tissues where both KCNK9 and KCNK3 are expressed, contributing to the lung-specific phenotype observed clinically in patients with PAH because of KCNK3 mutations.
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Affiliation(s)
- Michael S Bohnen
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY
| | | | - Cecile Terrenoire
- Department of Biophysics, Paulista School of Medicine, Federal University of Sao Paulo, Sao Paulo, Brazil
| | - Jack Jnani
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Kevin J Sampson
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Wendy K Chung
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, NY
| | - Robert S Kass
- Department of Pharmacology, College of Physicians and Surgeons, Columbia University, New York, NY
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13
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Muscarinic receptors in adrenal chromaffin cells: physiological role and regulation of ion channels. Pflugers Arch 2017; 470:29-38. [DOI: 10.1007/s00424-017-2047-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 07/21/2017] [Accepted: 07/23/2017] [Indexed: 10/19/2022]
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14
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Leitner MG, Michel N, Behrendt M, Dierich M, Dembla S, Wilke BU, Konrad M, Lindner M, Oberwinkler J, Oliver D. Direct modulation of TRPM4 and TRPM3 channels by the phospholipase C inhibitor U73122. Br J Pharmacol 2016; 173:2555-69. [PMID: 27328745 DOI: 10.1111/bph.13538] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 06/10/2016] [Accepted: 06/15/2016] [Indexed: 02/01/2023] Open
Abstract
BACKGROUND AND PURPOSE Signalling through phospholipase C (PLC) controls many cellular processes. Much information on the relevance of this important pathway has been derived from pharmacological inhibition of the enzymatic activity of PLC. We found that the most frequently employed PLC inhibitor, U73122, activates endogenous ionic currents in widely used cell lines. Given the extensive use of U73122 in research, we set out to identify these U73122-sensitive ion channels. EXPERIMENTAL APPROACH We performed detailed biophysical analysis of the U73122-induced currents in frequently used cell lines. KEY RESULTS At concentrations required to inhibit PLC, U73122 modulated the activity of transient receptor potential melastatin (TRPM) channels through covalent modification. U73122 was shown to be a potent agonist of ubiquitously expressed TRPM4 channels and activated endogenous TRPM4 channels in CHO cells independently of PLC and of the downstream second messengers PI(4,5)P2 and Ca(2+) . U73122 also potentiated Ca(2) (+) -dependent TRPM4 currents in human Jurkat T-cells, endogenous TRPM4 in HEK293T cells and recombinant human TRPM4. In contrast to TRPM4, TRPM3 channels were inhibited whereas the closely related TRPM5 channels were insensitive to U73122, showing that U73122 exhibits high specificity within the TRPM channel family. CONCLUSIONS AND IMPLICATIONS Given the widespread expression of TRPM4 and TRPM3 channels, these actions of U73122 must be considered when interpreting its effects on cell function. U73122 may also be useful for identifying and characterizing TRPM channels in native tissue, thus facilitating the analysis of their physiology.
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Affiliation(s)
- Michael G Leitner
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Niklas Michel
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Marc Behrendt
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Marlen Dierich
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Sandeep Dembla
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Bettina U Wilke
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Maik Konrad
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Moritz Lindner
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany.,Department of Ophthalmology, University of Bonn, Bonn, Germany
| | - Johannes Oberwinkler
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
| | - Dominik Oliver
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps-University Marburg, Marburg, Germany
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15
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16
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Thörn Pérez C, Hill RH, Grillner S. Substance P Depolarizes Lamprey Spinal Cord Neurons by Inhibiting Background Potassium Channels. PLoS One 2015. [PMID: 26197458 PMCID: PMC4510128 DOI: 10.1371/journal.pone.0133136] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Substance P is endogenously released in the adult lamprey spinal cord and accelerates the burst frequency of fictive locomotion. This is achieved by multiple effects on interneurons and motoneurons, including an attenuation of calcium currents, potentiation of NMDA currents and reduction of the reciprocal inhibition. While substance P also depolarizes spinal cord neurons, the underlying mechanism has not been resolved. Here we show that effects of substance P on background K+ channels are the main source for this depolarization. Hyperpolarizing steps induced inward currents during whole-cell voltage clamp that were reduced by substance P. These background K+ channels are pH sensitive and are selectively blocked by anandamide and AVE1231. These blockers counteracted the effect of substance P on these channels and the resting membrane potential depolarization in spinal cord neurons. Thus, we have shown now that substance P inhibits background K+ channels that in turn induce depolarization, which is likely to contribute to the frequency increase observed with substance P during fictive locomotion.
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Affiliation(s)
- Carolina Thörn Pérez
- Nobel Institute for Neurophysiology, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Russell H. Hill
- Nobel Institute for Neurophysiology, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Sten Grillner
- Nobel Institute for Neurophysiology, Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
- * E-mail:
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17
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Phosphoinositide dynamics in the postsynaptic membrane compartment: Mechanisms and experimental approach. Eur J Cell Biol 2015; 94:401-14. [DOI: 10.1016/j.ejcb.2015.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
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18
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Bandulik S, Tauber P, Lalli E, Barhanin J, Warth R. Two-pore domain potassium channels in the adrenal cortex. Pflugers Arch 2015; 467:1027-42. [PMID: 25339223 PMCID: PMC4428839 DOI: 10.1007/s00424-014-1628-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 12/31/2022]
Abstract
The physiological control of steroid hormone secretion from the adrenal cortex depends on the function of potassium channels. The "two-pore domain K(+) channels" (K2P) TWIK-related acid sensitive K(+) channel 1 (TASK1), TASK3, and TWIK-related K(+) channel 1 (TREK1) are strongly expressed in adrenocortical cells. They confer a background K(+) conductance to these cells which is important for the K(+) sensitivity as well as for angiotensin II and adrenocorticotropic hormone-dependent stimulation of aldosterone and cortisol synthesis. Mice with single deletions of the Task1 or Task3 gene as well as Task1/Task3 double knockout mice display partially autonomous aldosterone synthesis. It appears that TASK1 and TASK3 serve different functions: TASK1 affects cell differentiation and prevents expression of aldosterone synthase in the zona fasciculata, while TASK3 controls aldosterone secretion in glomerulosa cells. TREK1 is involved in the regulation of cortisol secretion in fasciculata cells. These data suggest that a disturbed function of K2P channels could contribute to adrenocortical pathologies in humans.
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Affiliation(s)
- Sascha Bandulik
- Medical Cell Biology, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany,
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19
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Rinné S, Kiper AK, Schlichthörl G, Dittmann S, Netter MF, Limberg SH, Silbernagel N, Zuzarte M, Moosdorf R, Wulf H, Schulze-Bahr E, Rolfes C, Decher N. TASK-1 and TASK-3 may form heterodimers in human atrial cardiomyocytes. J Mol Cell Cardiol 2015; 81:71-80. [DOI: 10.1016/j.yjmcc.2015.01.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2014] [Revised: 12/30/2014] [Accepted: 01/27/2015] [Indexed: 11/29/2022]
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20
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Renigunta V, Schlichthörl G, Daut J. Much more than a leak: structure and function of K₂p-channels. Pflugers Arch 2015; 467:867-94. [PMID: 25791628 DOI: 10.1007/s00424-015-1703-7] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 03/09/2015] [Indexed: 11/27/2022]
Abstract
Over the last decade, we have seen an enormous increase in the number of experimental studies on two-pore-domain potassium channels (K2P-channels). The collection of reviews and original articles compiled for this special issue of Pflügers Archiv aims to give an up-to-date summary of what is known about the physiology and pathophysiology of K2P-channels. This introductory overview briefly describes the structure of K2P-channels and their function in different organs. Its main aim is to provide some background information for the 19 reviews and original articles of this special issue of Pflügers Archiv. It is not intended to be a comprehensive review; instead, this introductory overview focuses on some unresolved questions and controversial issues, such as: Do K2P-channels display voltage-dependent gating? Do K2P-channels contribute to the generation of action potentials? What is the functional role of alternative translation initiation? Do K2P-channels have one or two or more gates? We come to the conclusion that we are just beginning to understand the extremely complex regulation of these fascinating channels, which are often inadequately described as 'leak channels'.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037, Marburg, Germany
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21
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Friedrich C, Rinné S, Zumhagen S, Kiper AK, Silbernagel N, Netter MF, Stallmeyer B, Schulze-Bahr E, Decher N. Gain-of-function mutation in TASK-4 channels and severe cardiac conduction disorder. EMBO Mol Med 2015; 6:937-51. [PMID: 24972929 PMCID: PMC4119356 DOI: 10.15252/emmm.201303783] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Analyzing a patient with progressive and severe cardiac conduction disorder combined with idiopathic ventricular fibrillation (IVF), we identified a splice site mutation in the sodium channel gene SCN5A. Due to the severe phenotype, we performed whole-exome sequencing (WES) and identified an additional mutation in the KCNK17 gene encoding the K2P potassium channel TASK-4. The heterozygous change (c.262G>A) resulted in the p.Gly88Arg mutation in the first extracellular pore loop. Mutant TASK-4 channels generated threefold increased currents, while surface expression was unchanged, indicating enhanced conductivity. When co-expressed with wild-type channels, the gain-of-function by G88R was conferred in a dominant-active manner. We demonstrate that KCNK17 is strongly expressed in human Purkinje cells and that overexpression of G88R leads to a hyperpolarization and strong slowing of the upstroke velocity of spontaneously beating HL-1 cells. Thus, we propose that a gain-of-function by TASK-4 in the conduction system might aggravate slowed conductivity by the loss of sodium channel function. Moreover, WES supports a second hit-hypothesis in severe arrhythmia cases and identified KCNK17 as a novel arrhythmia gene.
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Affiliation(s)
- Corinna Friedrich
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Sven Zumhagen
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Aytug K Kiper
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Nicole Silbernagel
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Michael F Netter
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
| | - Birgit Stallmeyer
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Eric Schulze-Bahr
- Department of Cardiovascular Medicine, Institute for Genetics of Heart Diseases (IfGH), University Hospital Münster, Münster, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Vegetative Physiology, University of Marburg, Marburg, Germany
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22
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The role of protein-protein interactions in the intracellular traffic of the potassium channels TASK-1 and TASK-3. Pflugers Arch 2015; 467:1105-20. [PMID: 25559843 DOI: 10.1007/s00424-014-1672-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 12/10/2014] [Accepted: 12/11/2014] [Indexed: 10/24/2022]
Abstract
The intracellular transport of membrane proteins is controlled by trafficking signals: Short peptide motifs that mediate the contact with COPI, COPII or various clathrin-associated coat proteins. In addition, many membrane proteins interact with accessory proteins that are involved in the sorting of these proteins to different intracellular compartments. In the K2P channels, TASK-1 and TASK-3, the influence of protein-protein interactions on sorting decisions has been studied in some detail. Both TASK paralogues interact with the adaptor protein 14-3-3; TASK-1 interacts, in addition, with the adaptor protein p11 (S100A10) and the endosomal SNARE protein syntaxin-8. The role of these interacting proteins in controlling the intracellular traffic of the channels and the underlying molecular mechanisms are summarised in this review. In the case of 14-3-3, the interacting protein masks a retention signal in the C-terminus of the channel; in the case of p11, the interacting protein carries a retention signal that localises the channel to the endoplasmic reticulum; and in the case of syntaxin-8, the interacting protein carries an endocytosis signal that complements an endocytosis signal of the channel. These examples illustrate some of the mechanisms by which interacting proteins may determine the itinerary of a membrane protein within a cell and suggest that the intracellular traffic of membrane proteins may be adapted to the specific functions of that protein by multiple protein-protein interactions.
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23
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The potassium current carried by TREK-1 channels in rat cardiac ventricular muscle. Pflugers Arch 2014; 467:1069-79. [PMID: 25539776 DOI: 10.1007/s00424-014-1678-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 01/13/2023]
Abstract
We studied the potassium current flowing through TREK-1 channels in rat cardiac ventricular myocytes. We separated the TREK-1 current from other current components by blocking most other channels with a blocker cocktail. We tried to inhibit the TREK-1 current by activating protein kinase A (PKA) with a mixture of forskolin and isobutyl-methylxanthine (IBMX). Activation of PKA blocked an outwardly rectifying current component at membrane potentials positive to -40 mV. At 37 °C, application of forskolin plus IBMX reduced the steady-state outward current measured at positive voltages by about 52 %. Application of the potassium channel blockers quinidine or tetrahexylammonium also reduced the steady-state outward current by about 50 %. Taken together, our results suggest that the increase in temperature from 22 to 37 °C increased the TREK-1 current by a factor of at least 5 and that the average density of the TREK-1 current in rat cardiomyocytes at 37 °C is about 1.5 pA/pF at +30 mV. The contribution of TREK-1 to the action potential was assessed by using a dynamic patch clamp technique. After subtraction of simulated TREK-1 currents, action potential duration at 50 or 90 % repolarisation was increased by about 12 %, indicating that TREK-1 may be functionally important in rat ventricular muscle. During sympathetic stimulation, inhibition of TREK-1 channels via PKA is expected to prolong the action potential primarily in subendocardial myocytes; this may decrease the transmural dispersion of repolarisation and thus may serve to prevent the occurrence of arrhythmias.
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24
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Ehling P, Cerina M, Budde T, Meuth SG, Bittner S. The CNS under pathophysiologic attack--examining the role of K₂p channels. Pflugers Arch 2014; 467:959-72. [PMID: 25482672 DOI: 10.1007/s00424-014-1664-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/17/2014] [Accepted: 11/28/2014] [Indexed: 10/24/2022]
Abstract
Members of the two-pore domain K(+) channel (K2P) family are increasingly recognized as being potential targets for therapeutic drugs and could play a role in the diagnosis and treatment of neurologic disorders. Their broad and diverse expression pattern in pleiotropic cell types, importance in cellular function, unique biophysical properties, and sensitivity toward pathophysiologic parameters represent the basis for their involvement in disorders of the central nervous system (CNS). This review will focus on multiple sclerosis (MS) and stroke, as there is growing evidence for the involvement of K2P channels in these two major CNS disorders. In MS, TASK1-3 channels are expressed on T lymphocytes and are part of a signaling network regulating Ca(2+)- dependent pathways that are mandatory for T cell activation, differentiation, and effector functions. In addition, TASK1 channels are involved in neurodegeneration, resulting in autoimmune attack of CNS cells. On the blood-brain barrier, TREK1 channels regulate immune cell trafficking under autoinflammatory conditions. Cerebral ischemia shares some pathophysiologic similarities with MS, including hypoxia and extracellular acidosis. On a cellular level, K2P channels can have both proapoptotic and antiapoptotic effects, either promoting neurodegeneration or protecting neurons from ischemic cell death. TASK1 and TREK1 channels have a neuroprotective effect on stroke development, whereas TASK2 channels have a detrimental effect on neuronal survival under ischemic conditions. Future research in preclinical models is needed to provide a more detailed understanding of the contribution of K2P channel family members to neurologic disorders, before translation to the clinic is an option.
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Affiliation(s)
- Petra Ehling
- Department of Neurology, University of Münster, Münster, Germany,
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Kim D, Kang D. Role of K₂p channels in stimulus-secretion coupling. Pflugers Arch 2014; 467:1001-11. [PMID: 25476848 DOI: 10.1007/s00424-014-1663-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 11/26/2014] [Accepted: 11/28/2014] [Indexed: 11/30/2022]
Abstract
Two-pore domain K(+) (K2P) channels are involved in a variety of physiological processes by virtue of their high basal activity and sensitivity to various biological stimuli. One of these processes is secretion of hormones and transmitters in response to stimuli such as hypoxia, acidosis, and receptor agonists. The rise in intracellular [Ca(2+)] ([Ca(2+)]i) that is critical for the secretory event can be achieved by several mechanisms: (a) inhibition of resting (background) K(+) channels, (b) activation of Na(+)/Ca(2+)-permeable channels, and (c) release of Ca(2+) from intracellular stores. Here, we discuss the role of TASK and TREK in stimulus-secretion mechanisms in carotid body chemoreceptor cells and adrenal medullary/cortical cells. Studies show that stimuli such as hypoxia and acidosis cause cell depolarization and transmitter/hormone secretion by inhibition of TASK or TREK. Subsequent elevation of [Ca(2+)]i produced by opening of voltage-dependent Ca(2+) channels then activates a Na(+)-permeable cation channel, presumably to help sustain the depolarization and [Ca(2+)]i. Agonists such as angiotensin II may elevate [Ca(2+)]i via multiple mechanisms involving both inhibition of TASK/TREK and Ca(2+) release from internal stores to cause aldosterone secretion. Thus, inhibition of resting (background) K(+) channels and subsequent activation of voltage-gated Ca(2+) channels and Na(+)-permeable non-selective cation channels may be a common ionic mechanism that lead to hormone and transmitter secretion.
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Affiliation(s)
- Donghee Kim
- Department of Physiology and Biophysics, Chicago Medical School, Rosalind Franklin University of Medicine and Science, 3333 Green Bay Road, North Chicago, IL, 60064, USA,
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Wilke BU, Lindner M, Greifenberg L, Albus A, Kronimus Y, Bünemann M, Leitner MG, Oliver D. Diacylglycerol mediates regulation of TASK potassium channels by Gq-coupled receptors. Nat Commun 2014; 5:5540. [PMID: 25420509 DOI: 10.1038/ncomms6540] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Accepted: 10/09/2014] [Indexed: 11/09/2022] Open
Abstract
The two-pore domain potassium (K2P) channels TASK-1 (KCNK3) and TASK-3 (KCNK9) are important determinants of background K(+) conductance and membrane potential. TASK-1/3 activity is regulated by hormones and transmitters that act through G protein-coupled receptors (GPCR) signalling via G proteins of the Gαq/11 subclass. How the receptors inhibit channel activity has remained unclear. Here, we show that TASK-1 and -3 channels are gated by diacylglycerol (DAG). Receptor-initiated inhibition of TASK required the activity of phospholipase C, but neither depletion of the PLC substrate PI(4,5)P2 nor release of the downstream messengers IP3 and Ca(2+). Attenuation of cellular DAG transients by DAG kinase or lipase suppressed receptor-dependent inhibition, showing that the increase in cellular DAG-but not in downstream lipid metabolites-mediates channel inhibition. The findings identify DAG as the signal regulating TASK channels downstream of GPCRs and define a novel role for DAG that directly links cellular DAG dynamics to excitability.
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Affiliation(s)
- Bettina U Wilke
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Moritz Lindner
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Lea Greifenberg
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Alexandra Albus
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Yannick Kronimus
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Moritz Bünemann
- Department of Pharmacology and Clinical Pharmacy, Philipps University, 35032 Marburg, Germany
| | - Michael G Leitner
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
| | - Dominik Oliver
- Institute of Physiology and Pathophysiology, Department of Neurophysiology, Philipps University, Deutschhausstr. 1-2, 35037 Marburg, Germany
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The role of acid-sensitive two-pore domain potassium channels in cardiac electrophysiology: focus on arrhythmias. Pflugers Arch 2014; 467:1055-67. [PMID: 25404566 DOI: 10.1007/s00424-014-1637-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 10/14/2014] [Accepted: 10/21/2014] [Indexed: 10/24/2022]
Abstract
The current kinetics of two-pore domain potassium (K2P) channels resemble those of the steady-state K(+) currents being active during the plateau phase of cardiac action potentials. Recent studies support that K2P channels contribute to these cardiac currents and thereby influence action potential duration in the heart. Ten of the 15 K2P channels present in the human genome are sensitive to variations of the extracellular and/or intracellular pH value. This review focuses on a set of K2P channels which are inhibited by extracellular protons, including the subgroup of tandem of P domains in a weak inward-rectifying K(+) (TWIK)-related acid-sensitive potassium (TASK) and TWIK-related alkaline-activated K(+) (TALK) channels. The role of TWIK-1 in the heart is also discussed since, after successful expression, an extracellular pH dependence, similar to that of TASK-1, was described as a hallmark of TWIK-1. The expression profile in cardiac tissue of different species and the functional data in the heart are summarized. The distinct role of the different acid-sensitive K2P channels in cardiac electrophysiology, inherited forms of arrhythmias and pharmacology, and their role as drug targets is currently emerging and is the subject of this review.
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Bista P, Pawlowski M, Cerina M, Ehling P, Leist M, Meuth P, Aissaoui A, Borsotto M, Heurteaux C, Decher N, Pape HC, Oliver D, Meuth SG, Budde T. Differential phospholipase C-dependent modulation of TASK and TREK two-pore domain K+ channels in rat thalamocortical relay neurons. J Physiol 2014; 593:127-44. [PMID: 25556792 DOI: 10.1113/jphysiol.2014.276527] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 09/23/2014] [Indexed: 01/10/2023] Open
Abstract
KEY POINTS During the behavioural states of sleep and wakefulness thalamocortical relay neurons fire action potentials in high frequency bursts or tonic sequences, respectively. The modulation of specific K(+) channel types, termed TASK and TREK, allows these neurons to switch between the two modes of activity. In this study we show that the signalling lipids phosphatidylinositol 4,5-bisphosphate (PIP2) and diacylglycerol (DAG), which are components of their membrane environment, switch on and shut off TREK and TASK channels, respectively. These channel modulations contribute to a better understanding of the molecular basis of the effects of neurotransmitters such as ACh which are released by the brainstem arousal system. The present report introduces PIP2 and DAG as new elements of signal transduction in the thalamus. The activity of two-pore domain potassium channels (K2P ) regulates the excitability and firing modes of thalamocortical (TC) neurons. In particular, the inhibition of two-pore domain weakly inwardly rectifying K(+) channel (TWIK)-related acid-sensitive K(+) (TASK) channels and TWIK-related K(+) (TREK) channels, as a consequence of the stimulation of muscarinic ACh receptors (MAChRs) which are coupled to phosphoinositide-specific phospholipase C (PLCβ), induces a shift from burst to tonic firing. By using a whole cell patch-clamp approach, the contribution of the membrane-bound second messenger molecules phosphatidylinositol 4,5-bisphosphate (PIP2 ) and diacylglycerol (DAG) acting downstream of PLCβ was probed. The standing outward current (ISO ) was used to monitor the current through TASK and TREK channels in TC neurons. By exploiting different manoeuvres to change the intracellular PIP2 level in TC neurons, we here show that the scavenging of PIP2 (by neomycin) results in an increased muscarinic effect on ISO whereas increased availability of PIP2 (inclusion to the patch pipette; histone-based carrier) decreased muscarinic signalling. The degree of muscarinic inhibition specifically depends on phosphatidylinositol phosphate (PIP) and PIP2 but no other phospholipids (phosphatidic acid, phosphatidylserine). The use of specific blockers revealed that PIP2 is targeting TREK but not TASK channels. Furthermore, we demonstrate that the inhibition of TASK channels is induced by the application of the DAG analogue 1-oleoyl-2-acetyl-sn-glycerol (OAG). Under current clamp conditions the activation of MAChRs and PLCβ as well as the application of OAG resulted in membrane depolarization, while PIP2 application via histone carrier induced a hyperpolarization. These results demonstrate a differential role of PIP2 and DAG in K2P channel modulation in native neurons which allows a fine-tuned inhibition of TREK (via PIP2 depletion) and TASK (via DAG) channels following MAChR stimulation.
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Affiliation(s)
- Pawan Bista
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Robert-Koch-Straße 27a, D-48149, Münster, Germany
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Mori MX, Inoue R. New experimental trends for phosphoinositides research on ion transporter/channel regulation. J Pharmacol Sci 2014; 126:186-97. [PMID: 25367262 DOI: 10.1254/jphs.14r14cp] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Phosphoinositides(4,5)-bisphosphates [PI(4,5)P2] critically controls membrane excitability, the disruption of which leads to pathophysiological states. PI(4,5)P2 plays a primary role in regulating the conduction and gating properties of ion channels/transporters, through electrostatic and hydrophobic interactions that allow direct associations. In recent years, the development of many molecular tools have brought deep insights into the mechanisms underlying PI(4,5)P2-mediated regulation. This review summarizes the methods currently available to manipulate the cell membrane PI(4,5)P2 level including pharmacological interventions as well as newly designed molecular tools. We concisely introduce materials and experimental designs suitable for the study of PI(4,5)P2-mediated regulation of ion-conducting molecules, in order to assist researchers who are interested in this area. It is our further hope that the knowledge introduced in this review will help to promote our understanding about the pathology of diseases such as cardiac arrhythmias, bipolar disorders, and Alzheimer's disease which are somehow associated with a disruption of PI(4,5)P2 metabolism.
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Affiliation(s)
- Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, School of Engineering, Kyoto University, Japan
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Bista P, Cerina M, Ehling P, Leist M, Pape HC, Meuth SG, Budde T. The role of two-pore-domain background K⁺ (K₂p) channels in the thalamus. Pflugers Arch 2014; 467:895-905. [PMID: 25346156 DOI: 10.1007/s00424-014-1632-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/09/2014] [Accepted: 10/12/2014] [Indexed: 12/15/2022]
Abstract
The thalamocortical system is characterized by two fundamentally different activity states, namely synchronized burst firing and tonic action potential generation, which mainly occur during the behavioral states of sleep and wakefulness, respectively. The switch between the two firing modes is crucially governed by the bidirectional modulation of members of the K2P channel family, namely tandem of P domains in a weakly inward rectifying K(+) (TWIK)-related acid-sensitive K(+) (TASK) and TWIK-related K(+) (TREK) channels, in thalamocortical relay (TC) neurons. Several physicochemical stimuli including neurotransmitters, protons, di- and multivalent cations as well as clinically used drugs have been shown to modulate K2P channels in these cells. With respect to modulation of these channels by G-protein-coupled receptors, PLCβ plays a unique role with both substrate breakdown and product synthesis exerting important functions. While the degradation of PIP2 leads to the closure of TREK channels, the production of DAG induces the inhibition of TASK channels. Therefore, TASK and TREK channels were found to be central elements in the control of thalamic activity modes. Since research has yet focused on identifying the muscarinic pathway underling the modulation of TASK and TREK channels in TC neurons, future studies should address other thalamic cell types and members of the K2P channel family.
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Affiliation(s)
- Pawan Bista
- Institut für Physiologie I, Westfälische Wilhelms-Universität, Robert-Koch-Str. 27a, 48149, Münster, Germany
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Bond RC, Choisy SCM, Bryant SM, Hancox JC, James AF. Inhibition of a TREK-like K+ channel current by noradrenaline requires both β1- and β2-adrenoceptors in rat atrial myocytes. Cardiovasc Res 2014; 104:206-15. [PMID: 25205295 PMCID: PMC4174890 DOI: 10.1093/cvr/cvu192] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
AIMS Noradrenaline plays an important role in the modulation of atrial electrophysiology. However, the identity of the modulated channels, their mechanisms of modulation, and their role in the action potential remain unclear. This study aimed to investigate the noradrenergic modulation of an atrial steady-state outward current (IKss). METHODS AND RESULTS Rat atrial myocyte whole-cell currents were recorded at 36°C. Noradrenaline potently inhibited IKss (IC50 = 0.90 nM, 42.1 ± 4.3% at 1 µM, n = 7) and potentiated the L-type Ca(2+) current (ICaL, EC50 = 136 nM, 205 ± 40% at 1 µM, n = 6). Noradrenaline-sensitive IKss was weakly voltage-dependent, time-independent, and potentiated by the arachidonic acid analogue, 5,8,11,14-eicosatetraynoic acid (EYTA; 10 µM), or by osmotically induced membrane stretch. Noise analysis revealed a unitary conductance of 8.4 ± 0.42 pS (n = 8). The biophysical/pharmacological properties of IKss indicate a TREK-like K(+) channel. The effect of noradrenaline on IKss was abolished by combined β1-/β2-adrenoceptor antagonism (1 µM propranolol or 10 µM β1-selective atenolol and 100 nM β2-selective ICI-118,551 in combination), but not by β1- or β2-antagonist alone. The action of noradrenaline could be mimicked by β2-agonists (zinterol and fenoterol) in the presence of β1-antagonist. The action of noradrenaline on IKss, but not on ICaL, was abolished by pertussis toxin (PTX) treatment. The action of noradrenaline on ICaL was mediated by β1-adrenoceptors via a PTX-insensitive pathway. Noradrenaline prolonged APD30 by 52 ± 19% (n = 5; P < 0.05), and this effect was abolished by combined β1-/β2-antagonism, but not by atenolol alone. CONCLUSION Noradrenaline inhibits a rat atrial TREK-like K(+) channel current via a PTX-sensitive mechanism involving co-operativity of β1-/β2-adrenoceptors that contributes to atrial APD prolongation.
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Affiliation(s)
- Richard C Bond
- Bristol Cardiovascular Research Laboratories, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Stéphanie C M Choisy
- Bristol Cardiovascular Research Laboratories, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Simon M Bryant
- Bristol Cardiovascular Research Laboratories, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Jules C Hancox
- Bristol Cardiovascular Research Laboratories, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
| | - Andrew F James
- Bristol Cardiovascular Research Laboratories, School of Physiology and Pharmacology, University of Bristol, Medical Sciences Building, University Walk, Bristol BS8 1TD, UK
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Potent and selective inhibitors of the TASK-1 potassium channel through chemical optimization of a bis-amide scaffold. Bioorg Med Chem Lett 2014; 24:3968-73. [PMID: 25017033 DOI: 10.1016/j.bmcl.2014.06.032] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/09/2014] [Accepted: 06/11/2014] [Indexed: 01/10/2023]
Abstract
TASK-1 is a two-pore domain potassium channel that is important to modulating cell excitability, most notably in the context of neuronal pathways. In order to leverage TASK-1 for therapeutic benefit, its physiological role needs better characterization; however, designing selective inhibitors that avoid the closely related TASK-3 channel has been challenging. In this study, a series of bis-amide derived compounds were found to demonstrate improved TASK-1 selectivity over TASK-3 compared to reported inhibitors. Optimization of a marginally selective hit led to analog 35 which displays a TASK-1 IC50=16 nM with 62-fold selectivity over TASK-3 in an orthogonal electrophysiology assay.
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Renigunta V, Fischer T, Zuzarte M, Kling S, Zou X, Siebert K, Limberg MM, Rinné S, Decher N, Schlichthörl G, Daut J. Cooperative endocytosis of the endosomal SNARE protein syntaxin-8 and the potassium channel TASK-1. Mol Biol Cell 2014; 25:1877-91. [PMID: 24743596 PMCID: PMC4055267 DOI: 10.1091/mbc.e13-10-0592] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
SNARE proteins can have functions unrelated to membrane fusion. The unassembled form of the SNARE protein syntaxin-8 interacts with the K+ channel TASK-1; both proteins are internalized via clathrin-mediated endocytosis in a cooperative manner. This is a novel mechanism for the control of endocytosis by cargo proteins. The endosomal SNARE protein syntaxin-8 interacts with the acid-sensitive potassium channel TASK-1. The functional relevance of this interaction was studied by heterologous expression of these proteins (and mutants thereof) in Xenopus oocytes and in mammalian cell lines. Coexpression of syntaxin-8 caused a fourfold reduction in TASK-1 current, a corresponding reduction in the expression of TASK-1 at the cell surface, and a marked increase in the rate of endocytosis of the channel. TASK-1 and syntaxin-8 colocalized in the early endosomal compartment, as indicated by the endosomal markers 2xFYVE and rab5. The stimulatory effect of the SNARE protein on the endocytosis of the channel was abolished when both an endocytosis signal in TASK-1 and an endocytosis signal in syntaxin-8 were mutated. A syntaxin-8 mutant that cannot assemble with other SNARE proteins had virtually the same effect as wild-type syntaxin-8. Total internal reflection fluorescence microscopy showed formation and endocytosis of vesicles containing fluorescence-tagged clathrin, TASK-1, and/or syntaxin-8. Our results suggest that the unassembled form of syntaxin-8 and the potassium channel TASK-1 are internalized via clathrin-mediated endocytosis in a cooperative manner. This implies that syntaxin-8 regulates the endocytosis of TASK-1. Our study supports the idea that endosomal SNARE proteins can have functions unrelated to membrane fusion.
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Affiliation(s)
- Vijay Renigunta
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Thomas Fischer
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Marylou Zuzarte
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Stefan Kling
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Xinle Zou
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Kai Siebert
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Maren M Limberg
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Susanne Rinné
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Niels Decher
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Günter Schlichthörl
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
| | - Jürgen Daut
- Institute of Physiology and Pathophysiology, Marburg University, 35037 Marburg, Germany
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Clouthier DE, Passos-Bueno MR, Tavares ALP, Lyonnet S, Amiel J, Gordon CT. Understanding the basis of auriculocondylar syndrome: Insights from human, mouse and zebrafish genetic studies. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2013; 163C:306-17. [PMID: 24123988 DOI: 10.1002/ajmg.c.31376] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Among human birth defect syndromes, malformations affecting the face are perhaps the most striking due to cultural and psychological expectations of facial shape. One such syndrome is auriculocondylar syndrome (ACS), in which patients present with defects in ear and mandible development. Affected structures arise from cranial neural crest cells, a population of cells in the embryo that reside in the pharyngeal arches and give rise to most of the bone, cartilage and connective tissue of the face. Recent studies have found that most cases of ACS arise from defects in signaling molecules associated with the endothelin signaling pathway. Disruption of this signaling pathway in both mouse and zebrafish results in loss of identity of neural crest cells of the mandibular portion of the first pharyngeal arch and the subsequent repatterning of these cells, leading to homeosis of lower jaw structures into more maxillary-like structures. These findings illustrate the importance of endothelin signaling in normal human craniofacial development and illustrate how clinical and basic science approaches can coalesce to improve our understanding of the genetic basis of human birth defect syndromes. Further, understanding the genetic basis for ACS that lies outside of known endothelin signaling components may help elucidate unknown aspects critical to the establishment of neural crest cell patterning during facial morphogenesis.
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