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Steponenaite A, Lalic T, Atkinson L, Tanday N, Brown L, Mathie A, Cader ZM, Lall GS. TASK-3, two-pore potassium channels, contribute to circadian rhythms in the electrical properties of the suprachiasmatic nucleus and play a role in driving stable behavioural photic entrainment. Chronobiol Int 2024; 41:802-816. [PMID: 38757583 DOI: 10.1080/07420528.2024.2351515] [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: 08/24/2023] [Accepted: 04/19/2024] [Indexed: 05/18/2024]
Abstract
Stable and entrainable physiological circadian rhythms are crucial for overall health and well-being. The suprachiasmatic nucleus (SCN), the primary circadian pacemaker in mammals, consists of diverse neuron types that collectively generate a circadian profile of electrical activity. However, the mechanisms underlying the regulation of endogenous neuronal excitability in the SCN remain unclear. Two-pore domain potassium channels (K2P), including TASK-3, are known to play a significant role in maintaining SCN diurnal homeostasis by inhibiting neuronal activity at night. In this study, we investigated the role of TASK-3 in SCN circadian neuronal regulation and behavioural photoentrainment using a TASK-3 global knockout mouse model. Our findings demonstrate the importance of TASK-3 in maintaining SCN hyperpolarization during the night and establishing SCN sensitivity to glutamate. Specifically, we observed that TASK-3 knockout mice lacked diurnal variation in resting membrane potential and exhibited altered glutamate sensitivity both in vivo and in vitro. Interestingly, despite these changes, the mice lacking TASK-3 were still able to maintain relatively normal circadian behaviour.
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Affiliation(s)
| | - Tatjana Lalic
- Translational Molecular Neuroscience Group, University of Oxford, Oxford, UK
| | | | - Neil Tanday
- Medway School of Pharmacy, University of Kent, Kent, UK
| | - Lorna Brown
- Medway School of Pharmacy, University of Kent, Kent, UK
| | | | - Zameel M Cader
- Translational Molecular Neuroscience Group, University of Oxford, Oxford, UK
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2
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Lim XR, Harraz OF. Mechanosensing by Vascular Endothelium. Annu Rev Physiol 2024; 86:71-97. [PMID: 37863105 PMCID: PMC10922104 DOI: 10.1146/annurev-physiol-042022-030946] [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] [Indexed: 10/22/2023]
Abstract
Mechanical forces influence different cell types in our bodies. Among the earliest forces experienced in mammals is blood movement in the vascular system. Blood flow starts at the embryonic stage and ceases when the heart stops. Blood flow exposes endothelial cells (ECs) that line all blood vessels to hemodynamic forces. ECs detect these mechanical forces (mechanosensing) through mechanosensors, thus triggering physiological responses such as changes in vascular diameter. In this review, we focus on endothelial mechanosensing and on how different ion channels, receptors, and membrane structures detect forces and mediate intricate mechanotransduction responses. We further highlight that these responses often reflect collaborative efforts involving several mechanosensors and mechanotransducers. We close with a consideration of current knowledge regarding the dysregulation of endothelial mechanosensing during disease. Because hemodynamic disruptions are hallmarks of cardiovascular disease, studying endothelial mechanosensing holds great promise for advancing our understanding of vascular physiology and pathophysiology.
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Affiliation(s)
- Xin Rui Lim
- Department of Pharmacology, Larner College of Medicine and Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA;
| | - Osama F Harraz
- Department of Pharmacology, Larner College of Medicine and Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA;
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3
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Sörmann J, Schewe M, Proks P, Jouen-Tachoire T, Rao S, Riel EB, Agre KE, Begtrup A, Dean J, Descartes M, Fischer J, Gardham A, Lahner C, Mark PR, Muppidi S, Pichurin PN, Porrmann J, Schallner J, Smith K, Straub V, Vasudevan P, Willaert R, Carpenter EP, Rödström KEJ, Hahn MG, Müller T, Baukrowitz T, Hurles ME, Wright CF, Tucker SJ. Gain-of-function mutations in KCNK3 cause a developmental disorder with sleep apnea. Nat Genet 2022; 54:1534-1543. [PMID: 36195757 PMCID: PMC9534757 DOI: 10.1038/s41588-022-01185-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 08/09/2022] [Indexed: 11/07/2022]
Abstract
Sleep apnea is a common disorder that represents a global public health burden. KCNK3 encodes TASK-1, a K+ channel implicated in the control of breathing, but its link with sleep apnea remains poorly understood. Here we describe a new developmental disorder with associated sleep apnea (developmental delay with sleep apnea, or DDSA) caused by rare de novo gain-of-function mutations in KCNK3. The mutations cluster around the 'X-gate', a gating motif that controls channel opening, and produce overactive channels that no longer respond to inhibition by G-protein-coupled receptor pathways. However, despite their defective X-gating, these mutant channels can still be inhibited by a range of known TASK channel inhibitors. These results not only highlight an important new role for TASK-1 K+ channels and their link with sleep apnea but also identify possible therapeutic strategies.
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Affiliation(s)
- Janina Sörmann
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Marcus Schewe
- Institute of Physiology, Faculty of Medicine, Kiel University, Kiel, Germany
| | - Peter Proks
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
| | - Thibault Jouen-Tachoire
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK
- Department of Pharmacology, University of Oxford, Oxford, UK
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
| | - Shanlin Rao
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Elena B Riel
- Institute of Physiology, Faculty of Medicine, Kiel University, Kiel, Germany
| | | | | | - John Dean
- Department of Medical Genetics, NHS Grampian, Aberdeen, UK
| | - Maria Descartes
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Jan Fischer
- Institute for Clinical Genetics, Universitätsklinikum, Technischen Universität Dresden, Dresden, Germany
| | - Alice Gardham
- North West Thames Regional Genetics Service, London North West Healthcare NHS Trust, London, UK
| | | | - Paul R Mark
- Spectrum Health Medical Genetics, Grand Rapids, MI, USA
| | | | | | - Joseph Porrmann
- Institute for Clinical Genetics, Universitätsklinikum, Technischen Universität Dresden, Dresden, Germany
| | - Jens Schallner
- Department of Neuropediatrics, Universitätsklinikum, Technischen Universität Dresden, Dresden, Germany
| | - Kirstin Smith
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Volker Straub
- Institute of Translational and Clinical Research, Newcastle University, Newcastle upon Tyne, UK
| | - Pradeep Vasudevan
- University Hospitals of Leicester NHS Trust, Leicester Royal Infirmary, Leicester, UK
| | | | - Elisabeth P Carpenter
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK
- Centre for Medicines Discovery, University of Oxford, Oxford, UK
| | | | - Michael G Hahn
- Bayer AG, Research & Development, Pharmaceuticals, Wuppertal, Germany
| | - Thomas Müller
- Bayer AG, Research & Development, Pharmaceuticals, Wuppertal, Germany
| | - Thomas Baukrowitz
- Institute of Physiology, Faculty of Medicine, Kiel University, Kiel, Germany
| | - Matthew E Hurles
- Human Genetics Programme, Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - Caroline F Wright
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter, UK.
| | - Stephen J Tucker
- Clarendon Laboratory, Department of Physics, University of Oxford, Oxford, UK.
- Kavli Institute for Nanoscience Discovery, University of Oxford, Oxford, UK.
- OXION Initiative in Ion Channels and Disease, University of Oxford, Oxford, UK.
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4
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Scarpa GB, Starrett JR, Li GL, Brooks C, Morohashi Y, Yazaki-Sugiyama Y, Remage-Healey L. Estrogens rapidly shape synaptic and intrinsic properties to regulate the temporal precision of songbird auditory neurons. Cereb Cortex 2022; 33:3401-3420. [PMID: 35849820 PMCID: PMC10068288 DOI: 10.1093/cercor/bhac280] [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: 06/08/2022] [Revised: 06/20/2022] [Accepted: 06/22/2022] [Indexed: 01/14/2023] Open
Abstract
Sensory neurons parse millisecond-variant sound streams like birdsong and speech with exquisite precision. The auditory pallial cortex of vocal learners like humans and songbirds contains an unconventional neuromodulatory system: neuronal expression of the estrogen synthesis enzyme aromatase. Local forebrain neuroestrogens fluctuate when songbirds hear a song, and subsequently modulate bursting, gain, and temporal coding properties of auditory neurons. However, the way neuroestrogens shape intrinsic and synaptic properties of sensory neurons remains unknown. Here, using a combination of whole-cell patch clamp electrophysiology and calcium imaging, we investigate estrogenic neuromodulation of auditory neurons in a region resembling mammalian auditory association cortex. We found that estradiol rapidly enhances the temporal precision of neuronal firing via a membrane-bound G-protein coupled receptor and that estradiol rapidly suppresses inhibitory synaptic currents while sparing excitation. Notably, the rapid suppression of intrinsic excitability by estradiol was predicted by membrane input resistance and was observed in both males and females. These findings were corroborated by analysis of in vivo electrophysiology recordings, in which local estrogen synthesis blockade caused acute disruption of the temporal correlation of song-evoked firing patterns. Therefore, on a modulatory timescale, neuroestrogens alter intrinsic cellular properties and inhibitory neurotransmitter release to regulate the temporal precision of higher-order sensory neurons.
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Affiliation(s)
- Garrett B Scarpa
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, 639 N. Pleasant St., Amherst, MA 01003, United States
| | - Joseph R Starrett
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, 639 N. Pleasant St., Amherst, MA 01003, United States
| | - Geng-Lin Li
- Department of Otorhinolaryngology, Eye and ENT Hospital, Fudan University, 83 Fenyang Rd, Xuhui District, Shanghai 200031, China
| | - Colin Brooks
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, 639 N. Pleasant St., Amherst, MA 01003, United States
| | - Yuichi Morohashi
- Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna, Kunigami District, Okinawa, Japan
| | - Yoko Yazaki-Sugiyama
- Okinawa Institute of Science and Technology (OIST) Graduate University, 1919-1 Tancha, Onna, Kunigami District, Okinawa, Japan
| | - Luke Remage-Healey
- Neuroscience and Behavior, Center for Neuroendocrine Studies, University of Massachusetts, 639 N. Pleasant St., Amherst, MA 01003, United States
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5
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Gain and loss of TASK3 channel function and its regulation by novel variation cause KCNK9 imprinting syndrome. Genome Med 2022; 14:62. [PMID: 35698242 PMCID: PMC9195326 DOI: 10.1186/s13073-022-01064-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 05/19/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Genomics enables individualized diagnosis and treatment, but large challenges remain to functionally interpret rare variants. To date, only one causative variant has been described for KCNK9 imprinting syndrome (KIS). The genotypic and phenotypic spectrum of KIS has yet to be described and the precise mechanism of disease fully understood. METHODS This study discovers mechanisms underlying KCNK9 imprinting syndrome (KIS) by describing 15 novel KCNK9 alterations from 47 KIS-affected individuals. We use clinical genetics and computer-assisted facial phenotyping to describe the phenotypic spectrum of KIS. We then interrogate the functional effects of the variants in the encoded TASK3 channel using sequence-based analysis, 3D molecular mechanic and dynamic protein modeling, and in vitro electrophysiological and functional methodologies. RESULTS We describe the broader genetic and phenotypic variability for KIS in a cohort of individuals identifying an additional mutational hotspot at p.Arg131 and demonstrating the common features of this neurodevelopmental disorder to include motor and speech delay, intellectual disability, early feeding difficulties, muscular hypotonia, behavioral abnormalities, and dysmorphic features. The computational protein modeling and in vitro electrophysiological studies discover variability of the impact of KCNK9 variants on TASK3 channel function identifying variants causing gain and others causing loss of conductance. The most consistent functional impact of KCNK9 genetic variants, however, was altered channel regulation. CONCLUSIONS This study extends our understanding of KIS mechanisms demonstrating its complex etiology including gain and loss of channel function and consistent loss of channel regulation. These data are rapidly applicable to diagnostic strategies, as KIS is not identifiable from clinical features alone and thus should be molecularly diagnosed. Furthermore, our data suggests unique therapeutic strategies may be needed to address the specific functional consequences of KCNK9 variation on channel function and regulation.
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6
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Mini-Review: Two Brothers in Crime - The Interplay of TRESK and TREK in Human Diseases. Neurosci Lett 2021; 769:136376. [PMID: 34852287 DOI: 10.1016/j.neulet.2021.136376] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 11/17/2021] [Accepted: 11/25/2021] [Indexed: 02/07/2023]
Abstract
TWIK-related spinal cord potassium (TRESK) and TWIK-related potassium (TREK) channels are both subfamilies of the two-pore domain potassium (K2P) channel group. Despite major structural, pharmacological, as well as biophysical differences, emerging data suggest that channels of these two subfamilies are functionally more closely related than previously assumed. Recent studies, for instance, indicate an assembling of TRESK and TREK subunits, leading to the formation of heterodimeric channels with different functional properties compared to homodimeric ones. Formation of tandems consisting of TRESK and TREK subunits might thus multiply the functional diversity of both TRESK and TREK activity. Based on the involvement of these channels in the pathophysiology of migraine, we here highlight the role as well as the impact of the interplay of TRESK and TREK subunits in the context of different disease settings. In this regard, we focus on their involvement in migraine and pain syndromes, as well as on their influence on (neuro-)inflammatory processes. Furthermore, we describe the potential implications for innovative therapeutic strategies that take advantage of TRESK and TREK modulation as well as obstacles encountered in the development of therapies related to the aforementioned diseases.
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7
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Huang W, Ke Y, Zhu J, Liu S, Cong J, Ye H, Guo Y, Wang K, Zhang Z, Meng W, Gao TM, Luhmann HJ, Kilb W, Chen R. TRESK channel contributes to depolarization-induced shunting inhibition and modulates epileptic seizures. Cell Rep 2021; 36:109404. [PMID: 34289346 DOI: 10.1016/j.celrep.2021.109404] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 03/19/2021] [Accepted: 06/23/2021] [Indexed: 11/18/2022] Open
Abstract
Glutamatergic and GABAergic synaptic transmission controls excitation and inhibition of postsynaptic neurons, whereas activity of ion channels modulates neuronal intrinsic excitability. However, it is unclear how excessive neuronal excitation affects intrinsic inhibition to regain homeostatic stability under physiological or pathophysiological conditions. Here, we report that a seizure-like sustained depolarization can induce short-term inhibition of hippocampal CA3 neurons via a mechanism of membrane shunting. This depolarization-induced shunting inhibition (DShI) mediates a non-synaptic, but neuronal intrinsic, short-term plasticity that is able to suppress action potential generation and postsynaptic responses by activated ionotropic receptors. We demonstrate that the TRESK channel significantly contributes to DShI. Disruption of DShI by genetic knockout of TRESK exacerbates the sensitivity and severity of epileptic seizures of mice, whereas overexpression of TRESK attenuates seizures. In summary, these results uncover a type of homeostatic intrinsic plasticity and its underlying mechanism. TRESK might represent a therapeutic target for antiepileptic drugs.
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Affiliation(s)
- Weiyuan Huang
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yue Ke
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jianping Zhu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Shuai Liu
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Jin Cong
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Hailin Ye
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China
| | - Yanwu Guo
- The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China
| | - Kewan Wang
- Department of Neurosurgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Zhenhai Zhang
- State Key Laboratory of Organ Failure Research, National Clinical Research Center for Kidney Disease, Division of Nephrology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Department of Bioinformatics, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Center for Precision Medicine, Guangzhou First People's Hospital, School of Medicine, South China University of Technology, Guangzhou 510030, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China
| | - Wenxiang Meng
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tian-Ming Gao
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China; State Key Laboratory of Organ Failure Research, Collaborative Innovation Center for Brain Science, Southern Medical University, Guangzhou 510515, China
| | - Heiko J Luhmann
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany
| | - Werner Kilb
- Institute of Physiology, University Medical Center of the Johannes Gutenberg University Mainz, Duesbergweg 6, Mainz 55120, Germany.
| | - Rongqing Chen
- Guangdong Province Key Laboratory of Psychiatric Disorders, Department of Neurobiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China; The National Key Clinic Specialty, The Engineering Technology Research Center of Education Ministry of China, Guangdong Provincial Key Laboratory on Brain Function Repair and Regeneration, Department of Neurosurgery, Zhujiang Hospital, Southern Medical University, Guangzhou 510282, China; Key Laboratory of Mental Health of the Ministry of Education, Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Southern Medical University, Guangzhou 510515, China.
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8
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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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9
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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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10
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Kohanski MA, Brown L, Orr M, Tan LH, Adappa ND, Palmer JN, Rubenstein RC, Cohen NA. Bitter taste receptor agonists regulate epithelial two-pore potassium channels via cAMP signaling. Respir Res 2021; 22:31. [PMID: 33509163 PMCID: PMC7844973 DOI: 10.1186/s12931-021-01631-0] [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: 10/21/2020] [Accepted: 01/20/2021] [Indexed: 11/20/2022] Open
Abstract
Background Epithelial solitary chemosensory cell (tuft cell) bitter taste signal transduction occurs through G protein coupled receptors and calcium-dependent signaling pathways. Type II taste cells, which utilize the same bitter taste signal transduction pathways, may also utilize cyclic adenosine monophosphate (cAMP) as an independent signaling messenger in addition to calcium. Methods In this work we utilized specific pharmacologic inhibitors to interrogate the short circuit current (Isc) of polarized nasal epithelial cells mounted in Ussing chambers to assess the electrophysiologic changes associated with bitter agonist (denatonium) treatment. We also assessed release of human β-defensin-2 from polarized nasal epithelial cultures following treatment with denatonium benzoate and/or potassium channel inhibitors. Results We demonstrate that the bitter taste receptor agonist, denatonium, decreases human respiratory epithelial two-pore potassium (K2P) current in polarized nasal epithelial cells mounted in Ussing chambers. Our data further suggest that this occurs via a cAMP-dependent signaling pathway. We also demonstrate that this decrease in potassium current lowers the threshold for denatonium to stimulate human β-defensin-2 release. Conclusions These data thus demonstrate that, in addition to taste transducing calcium-dependent signaling, bitter taste receptor agonists can also activate cAMP-dependent respiratory epithelial signaling pathways to modulate K2P currents. Bitter-agonist regulation of potassium currents may therefore serve as a means of rapid regional epithelial signaling, and further study of these pathways may provide new insights into regulation of mucosal ionic composition and innate mechanisms of epithelial defense.
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Affiliation(s)
- Michael A Kohanski
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania Medical Center, Perelman School of Medicine, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, USA.
| | - Lauren Brown
- Cystic Fibrosis Center, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Melissa Orr
- Cystic Fibrosis Center, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | - Li Hui Tan
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania Medical Center, Perelman School of Medicine, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, USA
| | - Nithin D Adappa
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania Medical Center, Perelman School of Medicine, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, USA
| | - James N Palmer
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania Medical Center, Perelman School of Medicine, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, USA
| | - Ronald C Rubenstein
- Cystic Fibrosis Center, The Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Department of Pediatrics, University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA, USA.,Division of Allergy and Pulmonary Medicine, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO, USA
| | - Noam A Cohen
- Department of Otorhinolaryngology-Head and Neck Surgery, Division of Rhinology, University of Pennsylvania Medical Center, Perelman School of Medicine, 5th Floor Ravdin Building, 3400 Spruce Street, Philadelphia, PA, USA.,Corporal Michael J. Crescenz Veterans Administration Medical Center, Philadelphia, PA, USA.,Monell Chemical Senses Institute, Philadelphia, PA, USA
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11
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Spanoghe J, Larsen LE, Craey E, Manzella S, Van Dycke A, Boon P, Raedt R. The Signaling Pathways Involved in the Anticonvulsive Effects of the Adenosine A 1 Receptor. Int J Mol Sci 2020; 22:ijms22010320. [PMID: 33396826 PMCID: PMC7794785 DOI: 10.3390/ijms22010320] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Revised: 12/22/2020] [Accepted: 12/27/2020] [Indexed: 12/20/2022] Open
Abstract
Adenosine acts as an endogenous anticonvulsant and seizure terminator in the brain. Many of its anticonvulsive effects are mediated through the activation of the adenosine A1 receptor, a G protein-coupled receptor with a wide array of targets. Activating A1 receptors is an effective approach to suppress seizures. This review gives an overview of the neuronal targets of the adenosine A1 receptor focusing in particular on signaling pathways resulting in neuronal inhibition. These include direct interactions of G protein subunits, the adenyl cyclase pathway and the phospholipase C pathway, which all mediate neuronal hyperpolarization and suppression of synaptic transmission. Additionally, the contribution of the guanyl cyclase and mitogen-activated protein kinase cascades to the seizure-suppressing effects of A1 receptor activation are discussed. This review ends with the cautionary note that chronic activation of the A1 receptor might have detrimental effects, which will need to be avoided when pursuing A1 receptor-based epilepsy therapies.
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Affiliation(s)
- Jeroen Spanoghe
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Lars E. Larsen
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Erine Craey
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Simona Manzella
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Annelies Van Dycke
- Department of Neurology, General Hospital Sint-Jan Bruges, 8000 Bruges, Belgium;
| | - Paul Boon
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
| | - Robrecht Raedt
- 4Brain, Department of Head and Skin, Ghent University, 9000 Ghent, Belgium; (J.S.); (L.E.L.); (E.C.); (S.M.); (P.B.)
- Correspondence:
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12
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Wen Z, Li Y, Bian C, Shi Q, Li Y. Characterization of two kcnk3 genes in rabbitfish (Siganus canaliculatus): Molecular cloning, distribution patterns and their potential roles in fatty acids metabolism and osmoregulation. Gen Comp Endocrinol 2020; 296:113546. [PMID: 32653428 DOI: 10.1016/j.ygcen.2020.113546] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 06/08/2020] [Accepted: 07/07/2020] [Indexed: 12/19/2022]
Abstract
KCNK3 is a two-pore-domain (K2P) potassium channel involved in maintaining ion homeostasis, mediating thermogenesis, controlling breath and modulating electrical membrane potential. Although the functions of this channel have been widely described in mammals, its roles in fishes are still rarely known. Here, we identified two kcnk3 genes from the euryhaline rabbitfish (Siganus canaliculatus), and their roles related to fatty acids metabolism and osmoregulation were investigated. The open reading frames of kcnk3a and kcnk3b were 1203 and 1176 bp in length, encoding 400 and 391 amino acids respectively. Multiple sequences alignment and phylogenetic analysis revealed that the two isotypes of kcnk3 were extensively presented in fishes. Quantitative real-time PCRs indicated that both genes were widely distributed in examined tissues but showed different patterns. kcnk3a primary distributed in adipose, eye, heart, and spleen tissues, while kcnk3b was mainly detectable in heart, kidney, muscle and spleen tissues. In vivo experiments showed that fish fed diets with fish oil as dietary lipid (rich in long chain polyunsaturated fatty acids, LC-PUFA) induced higher mRNA expression levels of kcnk3 genes in comparison with fish fed with plant oil diet at two different salinity environments (32 and 15‰). Meanwhile, the expression levels of kcnk3 genes were higher in seawater (32‰) than that in brackish water (15‰) when fishes were fed with both types of feeds. In vitro experiments with rabbitfish hepatocytes showed that LC-PUFA significantly improved hepatic kcnk3a expression level compared with treatment of linolenic acid. These results suggest that two kcnk3 genes are widely existed and they might be functionally related to fatty acids metabolism and osmoregulation in the rabbitfish.
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Affiliation(s)
- Zhengyong Wen
- BGI Education Center University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences BGI Marine BGI, Shenzhen 518083, China
| | - Yang Li
- Guangdong Provincial Key Laboratory of Marine Biotechnology Institute of Marine Sciences, Shantou University, Shantou 515063, China
| | - Chao Bian
- BGI Education Center University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences BGI Marine BGI, Shenzhen 518083, China
| | - Qiong Shi
- BGI Education Center University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences BGI Marine BGI, Shenzhen 518083, China.
| | - Yuanyou Li
- College of Marine Sciences of South, China Agricultural University & Guangdong Laboratory for Lingnan Modern Agriculture, Guangzhou 510642, China.
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Lalic T, Steponenaite A, Wei L, Vasudevan SR, Mathie A, Peirson SN, Lall GS, Cader MZ. TRESK is a key regulator of nocturnal suprachiasmatic nucleus dynamics and light adaptive responses. Nat Commun 2020; 11:4614. [PMID: 32929069 PMCID: PMC7490422 DOI: 10.1038/s41467-020-17978-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Accepted: 07/24/2020] [Indexed: 11/25/2022] Open
Abstract
The suprachiasmatic nucleus (SCN) is a complex structure dependent upon multiple mechanisms to ensure rhythmic electrical activity that varies between day and night, to determine circadian adaptation and behaviours. SCN neurons are exposed to glutamate from multiple sources including from the retino-hypothalamic tract and from astrocytes. However, the mechanism preventing inappropriate post-synaptic glutamatergic effects is unexplored and unknown. Unexpectedly we discovered that TRESK, a calcium regulated two-pore potassium channel, plays a crucial role in this system. We propose that glutamate activates TRESK through NMDA and AMPA mediated calcium influx and calcineurin activation to then oppose further membrane depolarisation and rising intracellular calcium. Hence, in the absence of TRESK, glutamatergic activity is unregulated leading to membrane depolarisation, increased nocturnal SCN firing, inverted basal calcium levels and impaired sensitivity in light induced phase delays. Our data reveals TRESK plays an essential part in SCN regulatory mechanisms and light induced adaptive behaviours. The suprachiasmatic nucleus (SCN) ensures rhythmic electrical activity that varies between day and night to determine circadian behaviours. The authors show that TRESK channels provide a feedback mechanism to maintain the SCN in the appropriate state for nocturnal light-induced behavioural changes.
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Affiliation(s)
- Tatjana Lalic
- Translational Molecular Neuroscience Group, Weatherall Institute of Molecular Medicine, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
| | - Aiste Steponenaite
- Medway School of Pharmacy, University of Kent and University of Greenwich, Anson Building, Central Avenue, Chatham, Kent, ME4 4TB, UK
| | - Liting Wei
- Translational Molecular Neuroscience Group, Weatherall Institute of Molecular Medicine, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | | | - Alistair Mathie
- Medway School of Pharmacy, University of Kent and University of Greenwich, Anson Building, Central Avenue, Chatham, Kent, ME4 4TB, UK
| | - Stuart N Peirson
- Sleep and Circadian Neuroscience Institute (SCNi), Nuffield Department of Clinical Neurosciences, University of Oxford, South Parks Road, Oxford, OX1 3RE, UK
| | - Gurprit S Lall
- Medway School of Pharmacy, University of Kent and University of Greenwich, Anson Building, Central Avenue, Chatham, Kent, ME4 4TB, UK.
| | - M Zameel Cader
- Translational Molecular Neuroscience Group, Weatherall Institute of Molecular Medicine, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK.
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14
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Clinical Importance of the Human Umbilical Artery Potassium Channels. Cells 2020; 9:cells9091956. [PMID: 32854241 PMCID: PMC7565333 DOI: 10.3390/cells9091956] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Potassium (K+) channels are usually predominant in the membranes of vascular smooth muscle cells (SMCs). These channels play an important role in regulating the membrane potential and vessel contractility-a role that depends on the vascular bed. Thus, the activity of K+ channels represents one of the main mechanisms regulating the vascular tone in physiological and pathophysiological conditions. Briefly, the activation of K+ channels in SMC leads to hyperpolarization and vasorelaxation, while its inhibition induces depolarization and consequent vascular contraction. Currently, there are four different types of K+ channels described in SMCs: voltage-dependent K+ (KV) channels, calcium-activated K+ (KCa) channels, inward rectifier K+ (Kir) channels, and 2-pore domain K+ (K2P) channels. Due to the fundamental role of K+ channels in excitable cells, these channels are promising therapeutic targets in clinical practice. Therefore, this review discusses the basic properties of the various types of K+ channels, including structure, cellular mechanisms that regulate their activity, and new advances in the development of activators and blockers of these channels. The vascular functions of these channels will be discussed with a focus on vascular SMCs of the human umbilical artery. Then, the clinical importance of K+ channels in the treatment and prevention of cardiovascular diseases during pregnancy, such as gestational hypertension and preeclampsia, will be explored.
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15
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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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16
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Fernández-Fernández D, Lamas JA. Metabotropic Modulation of Potassium Channels During Synaptic Plasticity. Neuroscience 2020; 456:4-16. [PMID: 32114098 DOI: 10.1016/j.neuroscience.2020.02.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/14/2020] [Accepted: 02/18/2020] [Indexed: 01/06/2023]
Abstract
Besides their primary function mediating the repolarization phase of action potentials, potassium channels exquisitely and ubiquitously regulate the resting membrane potential of neurons and therefore have a key role establishing their intrinsic excitability. This group of proteins is composed of a very diverse collection of voltage-dependent and -independent ion channels, whose specific distribution is finely tuned at the level of the synapse. Both at the presynaptic and postsynaptic membranes, different types of potassium channels are subjected to modulation by second messenger signaling cascades triggered by metabotropic receptors, which in this way serve as a link between neurotransmitter actions and changes in the neuron membrane excitability. On the one hand, by regulating the resting membrane potential of the postsynaptic membrane, potassium channels appear to be critical towards setting the threshold for the induction of long-term potentiation and depression. On the other hand, these channels maintain the presynaptic membrane potential under control, therefore influencing the probability of neurotransmitter release underlying different forms of short-term plasticity. In the present review, we examine in detail the role of metabotropic receptors translating their activation by different neurotransmitters into a final effect modulating several types of potassium channels. Furthermore, we evaluate the consequences that this interplay has on the induction and maintenance of different forms of synaptic plasticity.
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Affiliation(s)
- D Fernández-Fernández
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain.
| | - J A Lamas
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
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17
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Undem BJ, Sun H. Molecular/Ionic Basis of Vagal Bronchopulmonary C-Fiber Activation by Inflammatory Mediators. Physiology (Bethesda) 2020; 35:57-68. [PMID: 31799905 PMCID: PMC6985783 DOI: 10.1152/physiol.00014.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 06/03/2019] [Indexed: 12/11/2022] Open
Abstract
Stimulation of bronchopulmonary vagal afferent C fibers by inflammatory mediators can lead to coughing, chest tightness, and changes in breathing pattern, as well as reflex bronchoconstriction and secretions. These responses serve a defensive function in healthy lungs but likely contribute to many of the signs and symptoms of inflammatory airway diseases. A better understanding of the mechanisms underlying the activation of bronchopulmonary C-fiber terminals may lead to novel therapeutics that would work in an additive or synergic manner with existing anti-inflammatory strategies.
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Affiliation(s)
| | - Hui Sun
- Johns Hopkins University, Baltimore, Maryland
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18
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Wen ZY, Bian C, You X, Zhang X, Li J, Zhan Q, Peng Y, Li YY, Shi Q. Characterization of two kcnk3 genes in Nile tilapia (Oreochromis niloticus): Molecular cloning, tissue distribution, and transcriptional changes in various salinity of seawater. Genomics 2019; 112:2213-2222. [PMID: 31881264 DOI: 10.1016/j.ygeno.2019.12.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Revised: 12/23/2019] [Accepted: 12/23/2019] [Indexed: 02/07/2023]
Abstract
As one important member of the two-pore-domain potassium channel (K2P) family, potassium channel subfamily K member 3 (KCNK3) has been reported for thermogenesis regulation, energy homeostasis, membrane potential conduction, and pulmonary hypertension in mammals. However, its roles in fishes are far less examined and published. In the present study, we identified two kcnk3 genes (kcnk3a and kcnk3b) in an euryhaline fish, Nile tilapia (Oreochromis niloticus), by molecular cloning, genomic survey and laboratory experiments to investigate their potential roles for osmoregulation. We obtained full-length coding sequences of the kcnk3a and kcnk3b genes (1209 and 1173 bp), which encode 402 and 390 amino acids, respectively. Subsequent multiple sequence alignments, putative 3D-structure model prediction, genomic survey and phylogenetic analysis confirmed that two kcnk3 paralogs are widely presented in fish genomes. Interestingly, a DNA fragment inversion of a kcnk3a cluster was found in Cypriniforme in comparison with other fishes. Quantitative real-time PCRs demonstrated that both the tilapia kcnk3 genes were detected in all the examined tissues with a similar distribution pattern, and the highest transcriptions were observed in the heart. Meanwhile, both kcnk3 genes in the gill were proved to have a similar transcriptional change pattern in response to various salinity of seawater, implying that they might be involved in osmoregulation. Furthermore, three predicted transcription factors (arid3a, arid3b, and arid5a) of both kcnk3 genes also showed a similar pattern as their target genes in response to the various salinity, suggesting their potential positive regulatory roles. In summary, we for the first time characterized the two kcnk3 genes in Nile tilapia, and demonstrated their potential involvement in osmoregulation for this economically important fish.
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Affiliation(s)
- Zheng-Yong Wen
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Chao Bian
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Xinxin You
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Xinhui Zhang
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Jia Li
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Qiuyao Zhan
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Yuxiang Peng
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Yuan-You Li
- School of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
| | - Qiong Shi
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
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19
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Wen ZY, Wang J, Bian C, Zhang X, Li J, Peng Y, Zhan Q, Shi Q, Li YY. Molecular cloning of two kcnk3 genes from the Northern snakehead (Channa argus) for quantification of their transcriptions in response to fasting and refeeding. Gen Comp Endocrinol 2019; 281:49-57. [PMID: 31121162 DOI: 10.1016/j.ygcen.2019.05.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/06/2019] [Accepted: 05/18/2019] [Indexed: 01/18/2023]
Abstract
Potassium channel subfamily K member 3 (KCNK3) has been reported to play important roles in membrane potential conduction, pulmonary hypertension and thermogenesis regulation in mammals. However, its roles remain largely unknown and scarce reports were seen in fish. In the present study, we for the first time identified two kcnk3 genes (kcnk3a and kcnk3b) from the carnivorous Northern snakehead (Channa argus) by molecular cloning and a genomic survey. Subsequently, their transcription changes in response to different feeding status were investigated. Full-length coding sequences of the kcnk3a and kcnk3b genes are 1203 and 1176 bp, encoding 400 and 391 amino acids, respectively. Multiple alignments, 3D-structure prediction and phylogenetic analysis further suggested that these kcnk3 genes may be highly conserved in vertebrates. Tissue distribution analysis by real-time PCR demonstrated that both the snakehead kcnk3s were widely transcribed in majority of the examined tissues but with different distribution patterns. In a short-term (24-h) fasting experiment, we observed that brain kcnk3a and kcnk3b genes showed totally opposite transcription patterns. In a long-term (2-week) fasting and refeeding experiment, we also observed differential change patterns for the brain kcnk3 genes. In summary, our findings suggest that the two kcnk3 genes are close while present different transcription responses to fasting and refeeding. They therefore can be potentially selected as novel target genes for improvement of production and quality of this economically important fish.
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Affiliation(s)
- Zheng-Yong Wen
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; School of Marine Sciences, South China Agricultural University, Guangzhou 510642, China; College of Life Sciences, Conservation and Utilization of Fishes Resources in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Neijiang Normal University, Neijiang 641100, China
| | - Jun Wang
- College of Life Sciences, Conservation and Utilization of Fishes Resources in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province, Neijiang Normal University, Neijiang 641100, China
| | - Chao Bian
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Xinhui Zhang
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Jia Li
- Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China
| | - Yuxiang Peng
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China
| | - Qiuyao Zhan
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China
| | - Qiong Shi
- BGI Education Center, University of Chinese Academy of Sciences, Shenzhen 518083, China; Shenzhen Key Lab of Marine Genomics, Guangdong Provincial Key Lab of Molecular Breeding in Marine Economic Animals, BGI Academy of Marine Sciences, BGI Marine, BGI, Shenzhen 518083, China.
| | - Yuan-You Li
- School of Marine Sciences, South China Agricultural University, Guangzhou 510642, China.
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20
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Kamatham S, Waters CM, Schwingshackl A, Mancarella S. TREK-1 protects the heart against ischemia-reperfusion-induced injury and from adverse remodeling after myocardial infarction. Pflugers Arch 2019; 471:1263-1272. [PMID: 31511966 DOI: 10.1007/s00424-019-02306-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 08/12/2019] [Accepted: 08/22/2019] [Indexed: 11/28/2022]
Abstract
The TWIK-related K+ channel (TREK-1) is a two-pore-domain potassium channel that produces background leaky potassium currents. TREK-1 has a protective role against ischemia-induced neuronal damage. TREK-1 is also expressed in the heart, but its role in myocardial ischemia-reperfusion (IR)-induced injury has not been examined. In the current study, we used a TREK-1 knockout (KO) mouse model to show that TREK-1 has a critical role in the cardiac I/R-induced injury and during remodeling after myocardial infarction (MI). At baseline, TREK-1 KO mice had similar blood pressure and heart rate as the wild-type (WT) mice. However, the lack of TREK-1 was associated with increased susceptibility to ischemic injury and compromised functional recovery following ex vivo I/R-induced injury. TREK-1 deficiency increased infarct size following permanent coronary artery ligation, resulting in greater systolic dysfunction than the WT counterpart. Electrocardiographic (ECG) analysis revealed QT interval prolongation in TREK-1 KO mice, but normal heart rate (HR). Acutely isolated TREK-1 KO cardiomyocytes exhibited prolonged Ca2+ transient duration associated with action potential duration (APD) prolongation. Our data suggest that TREK-1 has a protective effect against I/R-induced injury and influences the post-MI remodeling processes by regulating membrane potential and maintaining intracellular Ca2+ homeostasis. These data suggest that TREK-1 activation could be an effective strategy to provide cardioprotection against ischemia-induced damage.
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Affiliation(s)
- Samuel Kamatham
- Department of Physiology, University of Tennessee Health Sciences Center, 71 S. Manassas Street, Memphis, TN, 38163, USA
| | - Christopher M Waters
- Department of Physiology, Saha Cardiovascular Research Center, University of Kentucky, Lexington, KY, USA
| | - Andreas Schwingshackl
- Department of Pediatrics, University of California Los Angeles, Los Angeles, CA, USA
| | - Salvatore Mancarella
- Department of Physiology, University of Tennessee Health Sciences Center, 71 S. Manassas Street, Memphis, TN, 38163, USA.
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Vastagh C, Solymosi N, Farkas I, Liposits Z. Proestrus Differentially Regulates Expression of Ion Channel and Calcium Homeostasis Genes in GnRH Neurons of Mice. Front Mol Neurosci 2019; 12:137. [PMID: 31213979 PMCID: PMC6554425 DOI: 10.3389/fnmol.2019.00137] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 05/10/2019] [Indexed: 11/29/2022] Open
Abstract
In proestrus, the changing gonadal hormone milieu alters the physiological properties of GnRH neurons and contributes to the development of the GnRH surge. We hypothesized that proestrus also influences the expression of different ion channel genes in mouse GnRH neurons. Therefore, we performed gene expression profiling of GnRH neurons collected from intact, proestrous and metestrous GnRH-GFP transgenic mice, respectively. Proestrus changed the expression of 37 ion channel and 8 calcium homeostasis-regulating genes. Voltage-gated sodium channels responded with upregulation of three alpha subunits (Scn2a1, Scn3a, and Scn9a). Within the voltage-gated potassium channel class, Kcna1, Kcnd3, Kcnh3, and Kcnq2 were upregulated, while others (Kcna4, Kcnc3, Kcnd2, and Kcng1) underwent downregulation. Proestrus also had impact on inwardly rectifying potassium channel subunits manifested in enhanced expression of Kcnj9 and Kcnj10 genes, whereas Kcnj1, Kcnj11, and Kcnj12 subunit genes were downregulated. The two-pore domain potassium channels also showed differential expression with upregulation of Kcnk1 and reduced expression of three subunit genes (Kcnk7, Kcnk12, and Kcnk16). Changes in expression of chloride channels involved both the voltage-gated (Clcn3 and Clcn6) and the intracellular (Clic1) subtypes. Regarding the pore-forming alpha-1 subunits of voltage-gated calcium channels, two (Cacna1b and Cacna1h) were upregulated, while Cacna1g showed downregulation. The ancillary subunits were also differentially regulated (Cacna2d1, Cacna2d2, Cacnb1, Cacnb3, Cacnb4, Cacng5, Cacng6, and Cacng8). In addition, ryanodine receptor 1 (Ryr1) gene was downregulated, while a transient receptor potential cation channel (Trpm3) gene showed enhanced expression. Genes encoding proteins regulating the intracellular calcium homeostasis were also influenced (Calb1, Hpca, Hpcal1, Hpcal4, Cabp7, Cab 39l, and Cib2). The differential expression of genes coding for ion channel proteins in GnRH neurons at late proestrus indicates that the altering hormone milieu contributes to remodeling of different kinds of ion channels of GnRH neurons, which might be a prerequisite of enhanced cellular activity of GnRH neurons and the subsequent surge release of the neurohormone.
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Affiliation(s)
- Csaba Vastagh
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Norbert Solymosi
- Centre for Bioinformatics, University of Veterinary Medicine, Budapest, Hungary
| | - Imre Farkas
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Zsolt Liposits
- Laboratory of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary.,Department of Neuroscience, Faculty of Information Technology and Bionics, Pázmány Péter Catholic University, Budapest, Hungary
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22
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Tian F, Qiu Y, Lan X, Li M, Yang H, Gao Z. A Small-Molecule Compound Selectively Activates K2P Channel TASK-3 by Acting at Two Distant Clusters of Residues. Mol Pharmacol 2019; 96:26-35. [DOI: 10.1124/mol.118.115303] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 04/17/2019] [Indexed: 11/22/2022] Open
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Albrecht S, Korr S, Nowack L, Narayanan V, Starost L, Stortz F, Araúzo‐Bravo MJ, Meuth SG, Kuhlmann T, Hundehege P. The K
2P
‐channel TASK1 affects Oligodendroglial differentiation but not myelin restoration. Glia 2019; 67:870-883. [DOI: 10.1002/glia.23577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Revised: 11/23/2018] [Accepted: 11/26/2018] [Indexed: 12/14/2022]
Affiliation(s)
- Stefanie Albrecht
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
| | - Sabrina Korr
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
- Department of Neurology with Institute of Translational NeurologyUniversity Hospital Münster Münster Germany
- Cells in Motion, Cluster of Excellence Münster Germany
| | - Luise Nowack
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
- Department of Neurology with Institute of Translational NeurologyUniversity Hospital Münster Münster Germany
| | - Venu Narayanan
- Department of Neurology with Institute of Translational NeurologyUniversity Hospital Münster Münster Germany
| | - Laura Starost
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
| | - Franziska Stortz
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
| | - Marcos J. Araúzo‐Bravo
- Group of Computational Biology and Systems Biomedicine, Biodonostia Health Research Institute San Sebastian Spain
- IKERBASQUE, Basque Foundation for Science Bilbao Spain
| | - Sven G. Meuth
- Department of Neurology with Institute of Translational NeurologyUniversity Hospital Münster Münster Germany
- Cells in Motion, Cluster of Excellence Münster Germany
| | - Tanja Kuhlmann
- Institute of NeuropathologyUniversity Hospital Münster Münster Germany
| | - Petra Hundehege
- Department of Neurology with Institute of Translational NeurologyUniversity Hospital Münster Münster Germany
- Cells in Motion, Cluster of Excellence Münster Germany
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24
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Kitagawa MG, Reynolds JO, Durgan D, Rodney G, Karmouty‐Quintana H, Bryan R, Pandit LM. Twik-2 -/- mouse demonstrates pulmonary vascular heterogeneity in intracellular pathways for vasocontractility. Physiol Rep 2019; 7:e13950. [PMID: 30632293 PMCID: PMC6328926 DOI: 10.14814/phy2.13950] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/06/2018] [Accepted: 11/15/2018] [Indexed: 11/24/2022] Open
Abstract
We have previously shown Twik-2-/- mice develop pulmonary hypertension and vascular remodeling. We hypothesized that distal pulmonary arteries (D-PAs) of the Twik-2-/- mice are hypercontractile under physiological venous conditions due to altered electrophysiologic properties between the conduit and resistance vessels in the pulmonary vascular bed. We measured resting membrane potential and intracellular calcium through Fura-2 in freshly digested pulmonary artery smooth muscles (PASMCs) from both the right main (RM-PA) and D-PA (distal) regions of pulmonary artery from WT and Twik-2-/- mice. Whole segments of RM-PAs and D-PAs from 20 to 24-week-old wildtype (WT) and Twik-2-/- mice were also pressurized between two glass micropipettes and bathed in buffer with either arterial or venous conditions. Abluminally-applied phenylephrine (PE) and U46619 were added to the buffer at log increments and vessel diameter was measured. All values were expressed as averages with ±SEM. Vasoconstrictor responses did not differ between WT and Twik-2-/- RM-PAs under arterial conditions. Under venous conditions, Twik-2-/- RM-PAs showed an increased sensitivity to PE with a lower EC50 (P = 0.02). Under venous conditions, Twik-2-/- D-PAs showed an increase maximal vasoconstrictor response to both phenylephrine and U46619 compared to the WT mice (P < 0.05). Isolated PASMCs from Twik-2 -/- D-PA were depolarized and had higher intracellular calcium levels compared to PASMCs from RM-PA of both WT and Twik-2-/- mice. These studies suggest that hypercontractile responses and electrophysiologic properties unique to the anatomic location of the D-PAs may contribute to pulmonary hypertensive vasculopathy.
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Affiliation(s)
| | | | | | | | | | | | - Lavannya M. Pandit
- Baylor College of MedicineHoustonTexas
- Michael E.DeBakey Veterans Affairs Medical CenterHoustonTexas
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25
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Neurokinin-3 receptor activation selectively prolongs atrial refractoriness by inhibition of a background K + channel. Nat Commun 2018; 9:4357. [PMID: 30341287 PMCID: PMC6195571 DOI: 10.1038/s41467-018-06530-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 09/07/2018] [Indexed: 11/29/2022] Open
Abstract
The cardiac autonomic nervous system (ANS) controls normal atrial electrical function. The cardiac ANS produces various neuropeptides, among which the neurokinins, whose actions on atrial electrophysiology are largely unknown. We here demonstrate that the neurokinin substance-P (Sub-P) activates a neurokinin-3 receptor (NK-3R) in rabbit, prolonging action potential (AP) duration through inhibition of a background potassium current. In contrast, ventricular AP duration was unaffected by NK-3R activation. NK-3R stimulation lengthened atrial repolarization in intact rabbit hearts and consequently suppressed arrhythmia duration and occurrence in a rabbit isolated heart model of atrial fibrillation (AF). In human atrial appendages, the phenomenon of NK-3R mediated lengthening of atrial repolarization was also observed. Our findings thus uncover a pathway to selectively modulate atrial AP duration by activation of a hitherto unidentified neurokinin-3 receptor in the membrane of atrial myocytes. NK-3R stimulation may therefore represent an anti-arrhythmic concept to suppress re-entry-based atrial tachyarrhythmias, including AF. The cardiac autonomic nervous system produces various neuropeptides, such as neurokinin substance-P (Sub-P), whose function remains largely unclear. Here, authors show that Sub-P causes a receptor-mediated prolongation of the atrial action potential through a reduced background potassium current, and prevents atrial fibrillation.
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26
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Park SJ, Yu Y, Wagner B, Valinsky WC, Lomax AE, Beyak MJ. Increased TASK channel-mediated currents underlie high-fat diet induced vagal afferent dysfunction. Am J Physiol Gastrointest Liver Physiol 2018; 315:G592-G601. [PMID: 29746171 DOI: 10.1152/ajpgi.00335.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
We have previously demonstrated that satiety sensing vagal afferent neurons are less responsive to meal-related stimuli in obesity because of reduced electrical excitability. As leak K+ currents are key determinants of membrane excitability, we hypothesized that leak K+ currents are increased in vagal afferents during obesity. Diet-induced obesity was induced by feeding C57Bl/6J mice a high-fat diet (HFF) (60% energy from fat) for 8-10 wk. In vitro extracellular recordings were performed on jejunal afferent nerves. Whole cell patch-clamp recordings were performed on mouse nodose ganglion neurons. Leak K+ currents were isolated using ion substitution and pharmacological blockers. mRNA for TWIK-related acid-sensitive K+ (TASK) subunits was measured using quantitative real-time PCR. Intestinal afferent responses to nutrient (oleate) and non-nutrient (ATP) stimuli were significantly decreased in HFF mice. Voltage clamp experiments revealed the presence of a voltage-insensitive resting potassium conductance that was increased by external alkaline pH and halothane, known properties of TASK currents. In HFF neurons, leak K+ current was approximately doubled and was reduced by TASK1 and TASK3 inhibitors. The halothane sensitive current was similarly increased. Quantitative PCR revealed the presence of mRNA encoding TASK1 (KCNK3) and TASK3 (KCNK9) channels in nodose neurons. TASK3 transcript was significantly increased in HFF mice. The reduction in vagal afferent excitability in obesity is due in part to an increase of resting (leak) K+ conductance. TASK channels may account for the impairment of satiety signaling in diet-induced obesity and thus is a therapeutic target for obesity treatment. NEW & NOTEWORTHY This study characterized the electrophysiological properties and gene expression of the TWIK-related acid-sensitive K+ (TASK) channel in vagal afferent neurons. TASK conductance was increased and contributed to decreased excitability in diet-induced obesity. TASK channels may account for the impairment of satiety signaling in diet-induced obesity and thus is a promising therapeutic target.
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Affiliation(s)
- Sung Jin Park
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Yang Yu
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Brittany Wagner
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - William C Valinsky
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Alan E Lomax
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
| | - Michael J Beyak
- Gastrointestinal Disease Research Unit, Queen's University , Kingston, Ontario , Canada
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27
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Activation of galanin receptor 1 inhibits locus coeruleus neurons via GIRK channels. Biochem Biophys Res Commun 2018; 503:79-85. [DOI: 10.1016/j.bbrc.2018.05.181] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 05/26/2018] [Indexed: 01/15/2023]
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28
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Sonoda T, Lee SK, Birnbaumer L, Schmidt TM. Melanopsin Phototransduction Is Repurposed by ipRGC Subtypes to Shape the Function of Distinct Visual Circuits. Neuron 2018; 99:754-767.e4. [PMID: 30017393 PMCID: PMC6107377 DOI: 10.1016/j.neuron.2018.06.032] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 01/07/2018] [Accepted: 06/20/2018] [Indexed: 12/15/2022]
Abstract
Melanopsin is expressed in distinct types of intrinsically photosensitive retinal ganglion cells (ipRGCs), which drive behaviors from circadian photoentrainment to contrast detection. A major unanswered question is how the same photopigment, melanopsin, influences such vastly different functions. Here we show that melanopsin's role in contrast detection begins in the retina, via direct effects on M4 ipRGC (ON alpha RGC) signaling. This influence persists across an unexpectedly wide range of environmental light levels ranging from starlight to sunlight, which considerably expands the functional reach of melanopsin on visual processing. Moreover, melanopsin increases the excitability of M4 ipRGCs via closure of potassium leak channels, a previously unidentified target of the melanopsin phototransduction cascade. Strikingly, this mechanism is selective for image-forming circuits, as M1 ipRGCs (involved in non-image forming behaviors), exhibit a melanopsin-mediated decrease in excitability. Thus, melanopsin signaling is repurposed by ipRGC subtypes to shape distinct visual behaviors.
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Affiliation(s)
- Takuma Sonoda
- Department of Neurobiology, Northwestern University, Evanston, IL, USA; Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Chicago, IL, USA
| | - Seul Ki Lee
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
| | - Lutz Birnbaumer
- Neurobiology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Durham, NC, USA; Institute of Biomedical Research (BIOMED), School of Medical Sciences, Catholic University of Argentina, Buenos Aires, Argentina
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern University, Evanston, IL, USA.
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29
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Belle MDC, Diekman CO. Neuronal oscillations on an ultra-slow timescale: daily rhythms in electrical activity and gene expression in the mammalian master circadian clockwork. Eur J Neurosci 2018; 48:2696-2717. [PMID: 29396876 DOI: 10.1111/ejn.13856] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 01/16/2018] [Accepted: 01/28/2018] [Indexed: 12/17/2022]
Abstract
Neuronal oscillations of the brain, such as those observed in the cortices and hippocampi of behaving animals and humans, span across wide frequency bands, from slow delta waves (0.1 Hz) to ultra-fast ripples (600 Hz). Here, we focus on ultra-slow neuronal oscillators in the hypothalamic suprachiasmatic nuclei (SCN), the master daily clock that operates on interlocking transcription-translation feedback loops to produce circadian rhythms in clock gene expression with a period of near 24 h (< 0.001 Hz). This intracellular molecular clock interacts with the cell's membrane through poorly understood mechanisms to drive the daily pattern in the electrical excitability of SCN neurons, exhibiting an up-state during the day and a down-state at night. In turn, the membrane activity feeds back to regulate the oscillatory activity of clock gene programs. In this review, we emphasise the circadian processes that drive daily electrical oscillations in SCN neurons, and highlight how mathematical modelling contributes to our increasing understanding of circadian rhythm generation, synchronisation and communication within this hypothalamic region and across other brain circuits.
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Affiliation(s)
- Mino D C Belle
- Institute of Clinical and Biomedical Sciences, University of Exeter Medical School, University of Exeter, Exeter, EX4 4PS, UK
| | - Casey O Diekman
- Department of Mathematical Sciences, New Jersey Institute of Technology, Newark, NJ, USA.,Institute for Brain and Neuroscience Research, New Jersey Institute of Technology, Newark, NJ, USA
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30
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Brown DA. Regulation of neural ion channels by muscarinic receptors. Neuropharmacology 2017; 136:383-400. [PMID: 29154951 DOI: 10.1016/j.neuropharm.2017.11.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 10/26/2017] [Accepted: 11/13/2017] [Indexed: 12/20/2022]
Abstract
The excitable behaviour of neurons is determined by the activity of their endogenous membrane ion channels. Since muscarinic receptors are not themselves ion channels, the acute effects of muscarinic receptor stimulation on neuronal function are governed by the effects of the receptors on these endogenous neuronal ion channels. This review considers some principles and factors determining the interaction between subtypes and classes of muscarinic receptors with neuronal ion channels, and summarizes the effects of muscarinic receptor stimulation on a number of different channels, the mechanisms of receptor - channel transduction and their direct consequences for neuronal activity. Ion channels considered include potassium channels (voltage-gated, inward rectifier and calcium activated), voltage-gated calcium channels, cation channels and chloride channels. This article is part of the Special Issue entitled 'Neuropharmacology on Muscarinic Receptors'.
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Affiliation(s)
- David A Brown
- Department of Neuroscience, Physiology & Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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31
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Crosstalk between KCNK3-Mediated Ion Current and Adrenergic Signaling Regulates Adipose Thermogenesis and Obesity. Cell 2017; 171:836-848.e13. [PMID: 28988768 DOI: 10.1016/j.cell.2017.09.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2017] [Revised: 06/10/2017] [Accepted: 09/08/2017] [Indexed: 01/13/2023]
Abstract
Adrenergic stimulation promotes lipid mobilization and oxidation in brown and beige adipocytes, where the harnessed energy is dissipated as heat in a process known as adaptive thermogenesis. The signaling cascades and energy-dissipating pathways that facilitate thermogenesis have been extensively described, yet little is known about the counterbalancing negative regulatory mechanisms. Here, we identify a two-pore-domain potassium channel, KCNK3, as a built-in rheostat negatively regulating thermogenesis. Kcnk3 is transcriptionally wired into the thermogenic program by PRDM16, a master regulator of thermogenesis. KCNK3 antagonizes norepinephrine-induced membrane depolarization by promoting potassium efflux in brown adipocytes. This limits calcium influx through voltage-dependent calcium channels and dampens adrenergic signaling, thereby attenuating lipolysis and thermogenic respiration. Adipose-specific Kcnk3 knockout mice display increased energy expenditure and are resistant to hypothermia and obesity. These findings uncover a critical K+-Ca2+-adrenergic signaling axis that acts to dampen thermogenesis, maintain tissue homeostasis, and reveal an electrophysiological regulatory mechanism of adipocyte function.
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32
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Chang AJ. Acute oxygen sensing by the carotid body: from mitochondria to plasma membrane. J Appl Physiol (1985) 2017; 123:1335-1343. [PMID: 28819004 DOI: 10.1152/japplphysiol.00398.2017] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 08/11/2017] [Accepted: 08/12/2017] [Indexed: 12/12/2022] Open
Abstract
Maintaining oxygen homeostasis is crucial to the survival of animals. Mammals respond acutely to changes in blood oxygen levels by modulating cardiopulmonary function. The major sensor of blood oxygen that regulates breathing is the carotid body (CB), a small chemosensory organ located at the carotid bifurcation. When arterial blood oxygen levels drop in hypoxia, neuroendocrine cells in the CB called glomus cells are activated to signal to afferent nerves that project to the brain stem. The mechanism by which hypoxia stimulates CB sensory activity has been the subject of many studies over the past 90 years. Two discrete models emerged that argue for the seat of oxygen sensing to lie either in the plasma membrane or mitochondria of CB cells. Recent studies are bridging the gap between these models by identifying hypoxic signals generated by changes in mitochondrial function in the CB that can be sensed by plasma membrane proteins on glomus cells. The CB is important for physiological adaptation to hypoxia, and its dysfunction contributes to sympathetic hyperactivity in common conditions such as sleep-disordered breathing, chronic heart failure, and insulin resistance. Understanding the basic mechanism of oxygen sensing in the CB could allow us to develop strategies to target this organ for therapy. In this short review, I will describe two historical models of CB oxygen sensing and new findings that are integrating these models.
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Affiliation(s)
- Andy J Chang
- Department of Physiology and Cardiovascular Research Institute, University of California, San Francisco, San Francisco, California
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33
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Hughes S, Foster RG, Peirson SN, Hankins MW. Expression and localisation of two-pore domain (K2P) background leak potassium ion channels in the mouse retina. Sci Rep 2017; 7:46085. [PMID: 28443635 PMCID: PMC5405414 DOI: 10.1038/srep46085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
Two-pore domain (K2P) potassium channels perform essential roles in neuronal function. These channels produce background leak type potassium currents that act to regulate resting membrane potential and levels of cellular excitability. 15 different K2P channels have been identified in mammals and these channels perform important roles in a wide number of physiological systems. However, to date there is only limited data available concerning the expression and role of K2P channels in the retina. In this study we conduct the first comprehensive study of K2P channel expression in the retina. Our data show that K2P channels are widely expressed in the mouse retina, with variations in expression detected at different times of day and throughout postnatal development. The highest levels of K2P channel expression are observed for Müller cells (TWIK-1, TASK-3, TRAAK, and TREK-2) and retinal ganglion cells (TASK-1, TREK-1, TWIK-1, TWIK-2 and TWIK-3). These data offer new insight into the channels that regulate the resting membrane potential and electrical activity of retinal cells, and suggests that K2P channels are well placed to act as central regulators of visual signalling pathways. The prominent role of K2P channels in neuroprotection offers novel avenues of research into the treatment of common retinal diseases.
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Affiliation(s)
- Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Russell G. Foster
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N. Peirson
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Mark W. Hankins
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
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34
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Phosphatidylinositol (4,5)-bisphosphate dynamically regulates the K 2P background K + channel TASK-2. Sci Rep 2017; 7:45407. [PMID: 28358046 PMCID: PMC5371824 DOI: 10.1038/srep45407] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Accepted: 02/23/2017] [Indexed: 12/22/2022] Open
Abstract
Two-pore domain K2P K+ channels responsible for the background K+ conductance and the resting membrane potential, are also finely regulated by a variety of chemical, physical and physiological stimuli. Hormones and transmitters acting through Gq protein-coupled receptors (GqPCRs) modulate the activity of various K2P channels but the signalling involved has remained elusive, in particular whether dynamic regulation by membrane PI(4,5)P2, common among other classes of K+ channels, affects K2P channels is controversial. Here we show that K2P K+ channel TASK-2 requires PI(4,5)P2 for activity, a dependence that accounts for its run down in the absence of intracellular ATP and its full recovery by addition of exogenous PI(4,5)P2, its inhibition by low concentrations of polycation PI scavengers, and inhibition by PI(4,5)P2 depletion from the membrane. Comprehensive mutagenesis suggests that PI(4,5)P2 interaction with TASK-2 takes place at C-terminus where three basic aminoacids are identified as being part of a putative binding site.
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35
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Chai S, Wan X, Nassal DM, Liu H, Moravec CS, Ramirez-Navarro A, Deschênes I. Contribution of two-pore K + channels to cardiac ventricular action potential revealed using human iPSC-derived cardiomyocytes. Am J Physiol Heart Circ Physiol 2017; 312:H1144-H1153. [PMID: 28341634 DOI: 10.1152/ajpheart.00107.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 03/16/2017] [Accepted: 03/22/2017] [Indexed: 01/12/2023]
Abstract
Two-pore K+ (K2p) channels have been described in modulating background conductance as leak channels in different physiological systems. In the heart, the expression of K2p channels is heterogeneous with equivocation regarding their functional role. Our objective was to determine the K2p expression profile and their physiological and pathophysiological contribution to cardiac electrophysiology. Induced pluripotent stem cells (iPSCs) generated from humans were differentiated into cardiomyocytes (iPSC-CMs). mRNA was isolated from these cells, commercial iPSC-CM (iCells), control human heart ventricular tissue (cHVT), and ischemic (iHF) and nonischemic heart failure tissues (niHF). We detected 10 K2p channels in the heart. Comparing quantitative PCR expression of K2p channels between human heart tissue and iPSC-CMs revealed K2p1.1, K2p2.1, K2p5.1, and K2p17.1 to be higher expressed in cHVT, whereas K2p3.1 and K2p13.1 were higher in iPSC-CMs. Notably, K2p17.1 was significantly lower in niHF tissues compared with cHVT. Action potential recordings in iCells after K2p small interfering RNA knockdown revealed prolongations in action potential depolarization at 90% repolarization for K2p2.1, K2p3.1, K2p6.1, and K2p17.1. Here, we report the expression level of 10 human K2p channels in iPSC-CMs and how they compared with cHVT. Importantly, our functional electrophysiological data in human iPSC-CMs revealed a prominent role in cardiac ventricular repolarization for four of these channels. Finally, we also identified K2p17.1 as significantly reduced in niHF tissues and K2p4.1 as reduced in niHF compared with iHF. Thus, we advance the notion that K2p channels are emerging as novel players in cardiac ventricular electrophysiology that could also be remodeled in cardiac pathology and therefore contribute to arrhythmias.NEW & NOTEWORTHY Two-pore K+ (K2p) channels are traditionally regarded as merely background leak channels in myriad physiological systems. Here, we describe the expression profile of K2p channels in human-induced pluripotent stem cell-derived cardiomyocytes and outline a salient role in cardiac repolarization and pathology for multiple K2p channels.
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Affiliation(s)
- Sam Chai
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio.,Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Xiaoping Wan
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Drew M Nassal
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio.,Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Haiyan Liu
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | | | - Angelina Ramirez-Navarro
- Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
| | - Isabelle Deschênes
- Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio; .,Heart and Vascular Research Center, Department of Medicine, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio; and
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36
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Tan Z, Liu Y, Xi W, Lou HF, Zhu L, Guo Z, Mei L, Duan S. Glia-derived ATP inversely regulates excitability of pyramidal and CCK-positive neurons. Nat Commun 2017; 8:13772. [PMID: 28128211 PMCID: PMC5290168 DOI: 10.1038/ncomms13772] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 10/31/2016] [Indexed: 12/19/2022] Open
Abstract
Astrocyte responds to neuronal activity with calcium waves and modulates synaptic transmission through the release of gliotransmitters. However, little is known about the direct effect of gliotransmitters on the excitability of neuronal networks beyond synapses. Here we show that selective stimulation of astrocytes expressing channelrhodopsin-2 in the CA1 area specifically increases the firing frequency of CCK-positive but not parvalbumin-positive interneurons and decreases the firing rate of pyramidal neurons, phenomena mimicked by exogenously applied ATP. Further evidences indicate that ATP-induced increase and decrease of excitability are caused, respectively, by P2Y1 receptor-mediated inhibition of a two-pore domain potassium channel and A1 receptor-mediated opening of a G-protein-coupled inwardly rectifying potassium channel. Moreover, the activation of ChR2-expressing astrocytes reduces the power of kainate-induced hippocampal ex vivo gamma oscillation. Thus, through distinct receptor subtypes coupled with different K+ channels, astrocyte-derived ATP differentially modulates the excitability of different types of neurons and efficiently controls the activity of neuronal network.
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Affiliation(s)
- Zhibing Tan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China.,Institute of Neuroscience and Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yu Liu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Wang Xi
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Hui-Fang Lou
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Liya Zhu
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Zhifei Guo
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia 30912, USA
| | - Shumin Duan
- Department of Neurobiology, Key Laboratory of Medical Neurobiology of The Ministry of Health of China, Key Laboratory of Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou 310058, China
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Woo J, Shin DH, Kim HJ, Yoo HY, Zhang YH, Nam JH, Kim WK, Kim SJ. Inhibition of TREK-2 K(+) channels by PI(4,5)P2: an intrinsic mode of regulation by intracellular ATP via phosphatidylinositol kinase. Pflugers Arch 2016; 468:1389-402. [PMID: 27283411 DOI: 10.1007/s00424-016-1847-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 05/28/2016] [Accepted: 05/30/2016] [Indexed: 11/28/2022]
Abstract
TWIK-related two-pore domain K(+) channels 1 and 2 (TREKs) are activated under various physicochemical conditions. However, the directions in which they are regulated by PI(4,5)P2 and intracellular ATP are not clearly presented yet. In this study, we investigated the effects of ATP and PI(4,5)P2 on overexpressed TREKs (HEK293T and COS-7) and endogenously expressed TREK-2 (mouse astrocytes and WEHI-231 B cells). In all of these cells, both TREK-1 and TREK-2 currents were spontaneously increased by dialysis with ATP-free pipette solution for whole-cell recording (ITREK-1,w-c and ITREK-2w-c) or by membrane excision for inside-out patch clamping without ATP (ITREK-1,i-o and ITREK-2,i-o). Steady state ITREK-2,i-o was reversibly decreased by 3 mM ATP applied to the cytoplasmic side, and this reduction was prevented by wortmannin, a PI-kinase inhibitor. An exogenous application of PI(4,5)P2 inhibited the spontaneously increased ITREKs,i-o, suggesting that intrinsic PI(4,5)P2 maintained by intracellular ATP and PI kinase may set the basal activity of TREKs in the intact cells. The inhibition of intrinsic TREK-2 by ATP was more prominent in WEHI-231 cells than astrocytes. Interestingly, unspecific screening of negative charges by poly-L-lysine also inhibited ITREK-2,i-o. Application of PI(4,5)P2 after the poly-L-lysine treatment showed dose-dependent dual effects, initial activation and subsequent inhibition of ITREK-2,i-o at low and high concentrations, respectively. In HEK293T cells coexpressing TREK-2 and a voltage-sensitive PI(4,5)P2 phosphatase, sustained depolarization increased ITREK-2,w-c initially (<5 s) but then decreased the current below the control level. In HEK293T cells coexpressing TREK-2 and type 3 muscarinic receptor, application of carbachol induced transient activation and sustained suppression of ITREK-2,w-c and cell-attached ITREK-2. The inhibition of TREK-2 by unspecific electrostatic quenching, extensive dephosphorylation, or sustained hydrolysis of PI(4,5)P2 suggests the existence of dual regulatory modes that depend on PI(4,5)P2 concentration.
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Affiliation(s)
- Joohan Woo
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 110-799, South Korea
| | - Dong Hoon Shin
- Division of Natural Medical Sciences, College of Health Science, Chosun University, Gwang-Ju, 501-759, South Korea
| | - Hyun Jong Kim
- Department of Physiology and Ion Channel Disease Research Center, College of Medicine, Dongguk University, Kyungju, 780-714, South Korea
| | - Hae Young Yoo
- Chung-Ang University Red Cross College of Nursing, Seoul, 100-031, South Korea
| | - Yin-Hua Zhang
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 110-799, South Korea
| | - Joo Hyun Nam
- Department of Physiology and Ion Channel Disease Research Center, College of Medicine, Dongguk University, Kyungju, 780-714, South Korea
| | - Woo Kyung Kim
- Department of Physiology and Ion Channel Disease Research Center, College of Medicine, Dongguk University, Kyungju, 780-714, South Korea
| | - Sung Joon Kim
- Department of Physiology, College of Medicine, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 110-799, South Korea.
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Rajani V, Zhang Y, Revill A, Funk G. The role of P2Y1 receptor signaling in central respiratory control. Respir Physiol Neurobiol 2016; 226:3-10. [DOI: 10.1016/j.resp.2015.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2015] [Accepted: 10/06/2015] [Indexed: 12/24/2022]
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Dagostin AA, Lovell PV, Hilscher MM, Mello CV, Leão RM. Control of Phasic Firing by a Background Leak Current in Avian Forebrain Auditory Neurons. Front Cell Neurosci 2015; 9:471. [PMID: 26696830 PMCID: PMC4674572 DOI: 10.3389/fncel.2015.00471] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 11/19/2015] [Indexed: 12/02/2022] Open
Abstract
Central neurons express a variety of neuronal types and ion channels that promote firing heterogeneity among their distinct neuronal populations. Action potential (AP) phasic firing, produced by low-threshold voltage-activated potassium currents (VAKCs), is commonly observed in mammalian brainstem neurons involved in the processing of temporal properties of the acoustic information. The avian caudomedial nidopallium (NCM) is an auditory area analogous to portions of the mammalian auditory cortex that is involved in the perceptual discrimination and memorization of birdsong and shows complex responses to auditory stimuli We performed in vitro whole-cell patch-clamp recordings in brain slices from adult zebra finches (Taeniopygia guttata) and observed that half of NCM neurons fire APs phasically in response to membrane depolarizations, while the rest fire transiently or tonically. Phasic neurons fired APs faster and with more temporal precision than tonic and transient neurons. These neurons had similar membrane resting potentials, but phasic neurons had lower membrane input resistance and time constant. Surprisingly phasic neurons did not express low-threshold VAKCs, which curtailed firing in phasic mammalian brainstem neurons, having similar VAKCs to other NCM neurons. The phasic firing was determined not by VAKCs, but by the potassium background leak conductances, which was more prominently expressed in phasic neurons, a result corroborated by pharmacological, dynamic-clamp, and modeling experiments. These results reveal a new role for leak currents in generating firing diversity in central neurons.
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Affiliation(s)
- André A Dagostin
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo Ribeirão Preto, Brazil
| | - Peter V Lovell
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR, USA
| | - Markus M Hilscher
- Brain Institute, Federal University of Rio Grande do Norte Natal, Brazil ; Institute for Analysis and Scientific Computing, Vienna University of Technology Vienna, Austria
| | - Claudio V Mello
- Department of Behavioral Neuroscience, Oregon Health and Science University, Portland OR, USA
| | - Ricardo M Leão
- Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo Ribeirão Preto, Brazil
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Kollert S, Dombert B, Döring F, Wischmeyer E. Activation of TRESK channels by the inflammatory mediator lysophosphatidic acid balances nociceptive signalling. Sci Rep 2015. [PMID: 26224542 PMCID: PMC4519772 DOI: 10.1038/srep12548] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
In dorsal root ganglia (DRG) neurons TRESK channels constitute a major current component of the standing outward current IKSO. A prominent physiological role of TRESK has been attributed to pain sensation. During inflammation mediators of pain e.g. lysophosphatidic acid (LPA) are released and modulate nociception. We demonstrate co-expression of TRESK and LPA receptors in DRG neurons. Heterologous expression of TRESK and LPA receptors in Xenopus oocytes revealed augmentation of basal K+ currents upon LPA application. In DRG neurons nociception can result from TRPV1 activation by capsaicin or LPA. Upon co-expression in Xenopus oocytes LPA simultaneously increased both depolarising TRPV1 and hyperpolarising TRESK currents. Patch-clamp recordings in cultured DRG neurons from TRESK[wt] mice displayed increased IKSO after application of LPA whereas under these conditions IKSO in neurons from TRESK[ko] mice remained unaltered. Under current-clamp conditions LPA application differentially modulated excitability in these genotypes upon depolarising pulses. Spike frequency was attenuated in TRESK[wt] neurons and, in contrast, augmented in TRESK[ko] neurons. Accordingly, excitation of nociceptive neurons by LPA is balanced by co-activation of TRESK channels. Hence excitation of sensory neurons is strongly controlled by the activity of TRESK channels, which therefore are good candidates for the treatment of pain disorders.
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Affiliation(s)
- Sina Kollert
- Institute of Physiology, AG Molecular Electrophysiology, University of Würzburg, 97070 Würzburg Germany
| | - Benjamin Dombert
- Institute for Clinical Neurobiology, University Hospital Würzburg, 97078 Würzburg, Germany
| | - Frank Döring
- Institute of Physiology, AG Molecular Electrophysiology, University of Würzburg, 97070 Würzburg Germany
| | - Erhard Wischmeyer
- Institute of Physiology, AG Molecular Electrophysiology, University of Würzburg, 97070 Würzburg Germany
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Ehling P, Bittner S, Meuth SG, Budde T. TASK, TREK & Co.: a mutable potassium channel family for diverse tasks in the brain. ACTA ACUST UNITED AC 2015. [DOI: 10.1007/s13295-015-0007-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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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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Functional study of TREK-1 potassium channels during rat heart development and cardiac ischemia using RNAi techniques. J Cardiovasc Pharmacol 2015; 64:142-50. [PMID: 24705172 DOI: 10.1097/fjc.0000000000000099] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
To explore the physiological and pathological significance of the 2-pore domain potassium channel TWIK-related K(+) (TREK)-1 in rat heart, its expression and role during heart development and cardiac ischemia were investigated. In the former study, the ventricles of Sprague Dawley rats were collected from embryo day 19 to postnatal 18 months and examined for mRNA and protein expression of TREK-1. It was found that both increased during development, reached a maximum at postnatal day 28, and remained higher at postnatal day 3 through to postnatal 18 months. In the latter study, protein expression of TREK-1 was examined after initiation of acute heart ischemia by ligation of the left anterior descending coronary artery. TREK-1 expression was found to be increased in the endocardium but unchanged in the epicardium. In primary cultured rat neonatal ventricular myocytes subjected to hypoxia (oxygen-glucose deprivation), TREK-1 expression was increased. In cultured neonatal cardiomyocytes, silencing of the TREK-1 gene by lentivirus delivery of the short-hairpin RNAs, L-sh-492 and L-sh-605, was found to promote their viability and number. In addition, both short-hairpin RNA provided protection against hypoxia-induced injury to cardiomyocytes in vitro. These results suggest that TREK-1 plays an important role in neonatal rat heart development and downregulation of TREK-1 may provide protection against ischemic injury. It seems that TREK-1 is a potential drug target for treatment of acute heart ischemia.
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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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TASK channels in arterial chemoreceptors and their role in oxygen and acid sensing. Pflugers Arch 2015; 467:1013-25. [PMID: 25623783 PMCID: PMC4428840 DOI: 10.1007/s00424-015-1689-1] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 01/06/2015] [Accepted: 01/07/2015] [Indexed: 01/05/2023]
Abstract
Arterial chemoreceptors play a vital role in cardiorespiratory control by providing the brain with information regarding blood oxygen, carbon dioxide, and pH. The main chemoreceptor, the carotid body, is composed of sensory (type 1) cells which respond to hypoxia or acidosis with a depolarising receptor potential which in turn activates voltage-gated calcium entry, neurosecretion and excitation of adjacent afferent nerves. The receptor potential is generated by inhibition of Twik-related acid-sensitive K(+) channel 1 and 3 (TASK1/TASK3) heterodimeric channels which normally maintain the cells' resting membrane potential. These channels are thought to be directly inhibited by acidosis. Oxygen sensitivity, however, probably derives from a metabolic signalling pathway. The carotid body, isolated type 1 cells, and all forms of TASK channel found in the type 1 cell, are highly sensitive to inhibitors of mitochondrial metabolism. Moreover, type1 cell TASK channels are activated by millimolar levels of MgATP. In addition to their role in the transduction of chemostimuli, type 1 cell TASK channels have also been implicated in the modulation of chemoreceptor function by a number of neurocrine/paracrine signalling molecules including adenosine, GABA, and serotonin. They may also be instrumental in mediating the depression of the acute hypoxic ventilatory response that occurs with some general anaesthetics. Modulation of TASK channel activity is therefore a key mechanism by which the excitability of chemoreceptors can be controlled. This is not only of physiological importance but may also offer a therapeutic strategy for the treatment of cardiorespiratory disorders that are associated with chemoreceptor dysfunction.
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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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47
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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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48
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Role of the TREK2 potassium channel in cold and warm thermosensation and in pain perception. Pain 2014; 155:2534-2544. [DOI: 10.1016/j.pain.2014.09.013] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/29/2014] [Accepted: 09/11/2014] [Indexed: 12/12/2022]
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49
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Mathie A, Veale EL. Two-pore domain potassium channels: potential therapeutic targets for the treatment of pain. Pflugers Arch 2014; 467:931-43. [DOI: 10.1007/s00424-014-1655-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/11/2014] [Accepted: 11/13/2014] [Indexed: 01/01/2023]
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50
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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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