1
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Liu Q, Zhang Y. Biological Clock Perspective in Rheumatoid Arthritis. Inflammation 2024:10.1007/s10753-024-02120-4. [PMID: 39126449 DOI: 10.1007/s10753-024-02120-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 06/13/2024] [Accepted: 08/01/2024] [Indexed: 08/12/2024]
Abstract
Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by systemic polyarticular pain, and its main pathological features include inflammatory cell infiltration, synovial fibroblast proliferation, and cartilage erosion. Immune cells, synovial cells and neuroendocrine factors play pivotal roles in the pathophysiological mechanism underlying rheumatoid arthritis. Biological clock genes regulate immune cell functions, which is linked to rhythmic changes in arthritis pathology. Additionally, the interaction between biological clock genes and neuroendocrine factors is also involved in rhythmic changes in rheumatoid arthritis. This review provides an overview of the contributions of circadian rhythm genes to RA pathology, including their interaction with the immune system and their involvement in regulating the secretion and function of neuroendocrine factors. A molecular understanding of the role of the circadian rhythm in RA may offer insights for effective disease management.
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Affiliation(s)
- Qingxue Liu
- Gengjiu Clinical College of Anhui Medical University; Anhui Zhongke Gengjiu Hospital, Hefei, 230051, China
| | - Yihao Zhang
- Department of Health Inspection and Quarantine, School of Public Health, Anhui Medical University, 81 Meishan Rd, Hefei, 230032, China.
- Key Laboratory of Environmental Toxicology of Anhui Higher Education Institutes, Anhui Medical University, Hefei, 230032, China.
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2
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Zhang G, Yang H, Wang Y, Liang H, Shi J, Cui J. Redox-dependent Cd 2+ inhibition of BK-type Ca 2+-activated K + channels. Biophys J 2024; 123:2076-2084. [PMID: 38400542 PMCID: PMC11309971 DOI: 10.1016/j.bpj.2024.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/11/2024] [Accepted: 02/20/2024] [Indexed: 02/25/2024] Open
Abstract
Large-conductance Ca2+-activated K+ channels (BK channels) are formed by Slo1 subunits as a homotetramer. Besides Ca2+, other divalent cations, such as Cd2+, also activate BK channels when applied intracellularly by shifting the conductance-voltage relation to more negative voltages. However, we found that if the inside-out patch containing BK channels was treated with solution containing reducing agents such as dithiothreitol (DTT), then subsequent Cd2+ application completely inhibited BK currents. The DTT-dependent Cd2+ inhibition could be reversed by treating the patch with solutions containing H2O2, suggesting that a redox reaction regulates the Cd2+ inhibition of BK channels. Similar DTT-dependent Cd2+ inhibition was also observed in a mutant BK channel, Core-MT, in which the cytosolic domain of the channel is deleted, and in the proton-activated Slo3 channels but not observed in the voltage-gated Shaker K+ channels. A possible mechanism for the DTT-dependent Cd2+ inhibition is that DTT treatment breaks one or more disulfide bonds between cysteine pairs in the BK channel protein and the freed thiol groups coordinate with Cd2+ to form an ion bridge that blocks the channel or locks the channel at the closed state. However, surprisingly, none of the mutations of all cysteine residues in Slo1 affect the DTT-dependent Cd2+ inhibition. These results are puzzling, with an apparent contradiction: on one hand, a redox reaction seems to regulate Cd2+ inhibition of the channel, but on the other hand, no cysteine residue in the Slo1 subunit seems to be involved in such inhibition.
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Affiliation(s)
- Guohui Zhang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Huanghe Yang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri; Department of Biochemistry, Duke University Medical Center, Durham, North Carolina
| | - Yuyin Wang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Hongwu Liang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Jingyi Shi
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri.
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3
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Li Q, Chen G, Yan J. Transmembrane determinants of voltage-gating differences between BK (Slo1) and Slo3 channels. Biophys J 2024; 123:2154-2166. [PMID: 38637987 PMCID: PMC11309983 DOI: 10.1016/j.bpj.2024.04.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 02/01/2024] [Accepted: 04/15/2024] [Indexed: 04/20/2024] Open
Abstract
Voltage-gated potassium channels are critical in modulating cellular excitability, with Slo (slowpoke) channels forming a unique family characterized by their large conductance and dual regulation by electrical signals and intracellular messengers. Despite their structural and evolutionary similarities, Slo1 and Slo3 channels exhibit significant differences in their voltage-gating properties. This study investigates the molecular determinants that differentiate the voltage-gating properties of human Slo1 and mouse Slo3 channels. Utilizing Slo1/Slo3 chimeras, we pinpointed the selectivity filter region as a key factor in the Slo3 channel's reduced conductance at negative voltages. The S6 transmembrane (TM) segment was identified as pivotal for the Slo3 channel's biphasic deactivation kinetics at these voltages. Additionally, the S4 and S6 TM segments were found to be responsible for the gradual slope in the Slo3 channel's conductance-voltage relationship, while multiple TM regions appear to be involved in the Slo3 channel's requirement of strong depolarization for activation. Mutations in the Slo1's S5 and S6 TM segments revealed three residues (I233, L302, and M304) that likely play a crucial role in the allosteric coupling between the voltage sensors and the pore gate.
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Affiliation(s)
- Qin Li
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas; Molecular & Translational Biology and Neuroscience Programs, MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Guanxing Chen
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas; Molecular & Translational Biology and Neuroscience Programs, MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, Texas
| | - Jiusheng Yan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas; Molecular & Translational Biology and Neuroscience Programs, MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, Texas.
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4
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Arake M, Ohta H, Nozawa T, Satoh Y, Fujita M, Nakata T, Meredith AL, Shinomiya N, Ishizuka T, Morimoto Y. BK channel dysfunction disrupts attention-controlled behaviors and altered perseverative responses in murine instrumental learning. Behav Brain Res 2024; 468:115015. [PMID: 38670533 DOI: 10.1016/j.bbr.2024.115015] [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: 02/27/2024] [Revised: 04/23/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024]
Abstract
This study examined the effect of knockout of KCNMA1 gene, coding for the BK channel, on cognitive and attentional functions in mice, with an aim to better understand its implications for human neurodevelopmental disorders. The study used the 3-choice serial reaction time task (3-CSRTT) to assess the learning performance, attentional abilities, and repetitive behaviors in mice lacking the KCNMA1 gene (KCNMA1-/-) compared to wild-type (WT) controls. Results showed no significant differences in learning accuracy between the two groups. However, KCNMA1-/- mice were more prone to omitting responses to stimuli. In addition, when the timing of cue presentation was randomized, the KCNMA1-/- showed premature responses. Notably, these mice also demonstrated a marked reduction in perseverative responses, which include repeated nose-poke behaviors following decisions. These findings highlight the involvement of the KCNMA1 gene in managing attention, impulsivity, and potentially moderating repetitive actions.
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Affiliation(s)
- Masashi Arake
- Department of Physiology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
| | - Hiroyuki Ohta
- Department of Pharmacology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan.
| | - Takashi Nozawa
- Department of Psychology, Mejiro University, Nakaochiai 4-31-1, Shinjuku-ku, Tokyo 161-8539, Japan
| | - Yasushi Satoh
- Department of Biochemistry, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
| | - Masanori Fujita
- Division of Environmental Medicine, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
| | - Takahiro Nakata
- Department of Molecular and Cellular Anatomy, Faculty of Health Promotional Sciences, Tokoha University, Hamamatsu, Shizuoka, Japan
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Nariyoshi Shinomiya
- Department of Integrative Physiology and Bio-Nano Medicine, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
| | - Toshiaki Ishizuka
- Department of Pharmacology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
| | - Yuji Morimoto
- Department of Physiology, National Defense Medical College, Namiki 3-2, Tokorozawa, Saitama 359-8513, Japan
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5
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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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6
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Gururaja Rao S, Lam A, Seeley S, Park J, Aruva S, Singh H. The BK Ca (slo) channel regulates the cardiac function of Drosophila. Physiol Rep 2024; 12:e15996. [PMID: 38561252 PMCID: PMC10984821 DOI: 10.14814/phy2.15996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 03/21/2024] [Accepted: 03/21/2024] [Indexed: 04/04/2024] Open
Abstract
The large conductance, calcium, and voltage-active potassium channels (BKCa) were originally discovered in Drosophila melanogaster as slowpoke (slo). They are extensively characterized in fly models as ion channels for their roles in neurological and muscular function, as well as aging. BKCa is known to modulate cardiac rhythm and is localized to the mitochondria. Activation of mitochondrial BKCa causes cardioprotection from ischemia-reperfusion injury, possibly via modulating mitochondrial function in adult animal models. However, the role of BKCa in cardiac function is not well-characterized, partially due to its localization to the plasma membrane as well as intracellular membranes and the wide array of cells present in mammalian hearts. Here we demonstrate for the first time a direct role for BKCa in cardiac function and cardioprotection from IR injury using the Drosophila model system. We have also discovered that the BKCa channel plays a role in the functioning of aging hearts. Our study establishes the presence of BKCa in the fly heart and ascertains its role in aging heart function.
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Affiliation(s)
- Shubha Gururaja Rao
- Department of Pharmaceutical and Biomedical SciencesThe Raabe College of Pharmacy, Ohio Northern UniversityAdaOhioUSA
- Department of Physiology and Cell BiologyThe Ohio State UniversityColumbusOhioUSA
| | - Alexander Lam
- Department of Physiology and Cell BiologyThe Ohio State UniversityColumbusOhioUSA
| | - Sarah Seeley
- Department of Pharmaceutical and Biomedical SciencesThe Raabe College of Pharmacy, Ohio Northern UniversityAdaOhioUSA
| | - Jeniffer Park
- Department of Physiology and Cell BiologyThe Ohio State UniversityColumbusOhioUSA
| | - Shriya Aruva
- Department of Physiology and Cell BiologyThe Ohio State UniversityColumbusOhioUSA
| | - Harpreet Singh
- Department of Physiology and Cell BiologyThe Ohio State UniversityColumbusOhioUSA
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7
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Echeverría F, Gonzalez-Sanabria N, Alvarado-Sanchez R, Fernández M, Castillo K, Latorre R. Large conductance voltage-and calcium-activated K + (BK) channel in health and disease. Front Pharmacol 2024; 15:1373507. [PMID: 38584598 PMCID: PMC10995336 DOI: 10.3389/fphar.2024.1373507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Accepted: 03/12/2024] [Indexed: 04/09/2024] Open
Abstract
Large Conductance Voltage- and Calcium-activated K+ (BK) channels are transmembrane pore-forming proteins that regulate cell excitability and are also expressed in non-excitable cells. They play a role in regulating vascular tone, neuronal excitability, neurotransmitter release, and muscle contraction. Dysfunction of the BK channel can lead to arterial hypertension, hearing disorders, epilepsy, and ataxia. Here, we provide an overview of BK channel functioning and the implications of its abnormal functioning in various diseases. Understanding the function of BK channels is crucial for comprehending the mechanisms involved in regulating vital physiological processes, both in normal and pathological conditions, controlled by BK. This understanding may lead to the development of therapeutic interventions to address BK channelopathies.
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Affiliation(s)
- Felipe Echeverría
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Naileth Gonzalez-Sanabria
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Rosangelina Alvarado-Sanchez
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Miguel Fernández
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Karen Castillo
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
- Centro de Investigación de Estudios Avanzados del Maule, Vicerrectoría de Investigación y Postgrado, Universidad Católica del Maule, Talca, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso, Instituto de Neurociencia, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
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8
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Abstract
The timing of life on Earth is remarkable: between individuals of the same species, a highly similar temporal pattern is observed, with shared periods of activity and inactivity each day. At the individual level, this means that over the course of a single day, a person alternates between two states. They are either upright, active, and communicative or they lie down in a state of (un)consciousness called sleep where even the characteristic of neuronal signals in the brain shows distinctive properties. The circadian clock governs both of these time stamps-activity and (apparent) inactivity-making them come and go consistently at the same approximate time each day. This behavior thus represents the meeting of two pervasive systems: the circadian clock and metabolism. In this article, we will describe what is known about how the circadian clock anticipates daily changes in oxygen usage, how circadian clock regulation may relate to normal physiology, and to hypoxia and ischemia that can result from pathologies such as myocardial infarction and stroke.
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Affiliation(s)
- Francesca Sartor
- Institute of Medical Psychology, Medical Faculty, LMU Munich, Germany (F.S., B.F.-B., M.M.)
| | - Borja Ferrero-Bordera
- Institute of Medical Psychology, Medical Faculty, LMU Munich, Germany (F.S., B.F.-B., M.M.)
| | - Jeffrey Haspel
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO (J.H.)
| | - Markus Sperandio
- Institute for Cardiovascular Physiology and Pathophysiology, Walter Brendel Center for Experimental Medicine, and the Biomedical Center (BMC), Medical Faculty, LMU Munich, Germany (M.S.)
| | - Paul M Holloway
- Radcliffe Department of Medicine, University of Oxford, United Kingdom (P.M.H.)
| | - Martha Merrow
- Institute of Medical Psychology, Medical Faculty, LMU Munich, Germany (F.S., B.F.-B., M.M.)
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9
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Meredith AL. BK Channelopathies and KCNMA1-Linked Disease Models. Annu Rev Physiol 2024; 86:277-300. [PMID: 37906945 DOI: 10.1146/annurev-physiol-030323-042845] [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: 11/02/2023]
Abstract
Novel KCNMA1 variants, encoding the BK K+ channel, are associated with a debilitating dyskinesia and epilepsy syndrome. Neurodevelopmental delay, cognitive disability, and brain and structural malformations are also diagnosed at lower incidence. More than half of affected individuals present with a rare negative episodic motor disorder, paroxysmal nonkinesigenic dyskinesia (PNKD3). The mechanistic relationship of PNKD3 to epilepsy and the broader spectrum of KCNMA1-associated symptomology is unknown. This review summarizes patient-associated KCNMA1 variants within the BK channel structure, functional classifications, genotype-phenotype associations, disease models, and treatment. Patient and transgenic animal data suggest delineation of gain-of-function (GOF) and loss-of-function KCNMA1 neurogenetic disease, validating two heterozygous alleles encoding GOF BK channels (D434G and N999S) as causing seizure and PNKD3. This discovery led to a variant-defined therapeutic approach for PNKD3, providing initial insight into the neurological basis. A comprehensive clinical definition of monogenic KCNMA1-linked disease and the neuronal mechanisms currently remain priorities for continued investigation.
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Affiliation(s)
- Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, USA;
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10
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Okhuarobo A, Kreifeldt M, Gandhi PJ, Lopez C, Martinez B, Fleck K, Bajo M, Bhattacharyya P, Dopico AM, Roberto M, Roberts AJ, Homanics GE, Contet C. Ethanol's interaction with BK channel α subunit residue K361 does not mediate behavioral responses to alcohol in mice. Mol Psychiatry 2024; 29:529-542. [PMID: 38135755 PMCID: PMC11116116 DOI: 10.1038/s41380-023-02346-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 11/27/2023] [Indexed: 12/24/2023]
Abstract
Large conductance potassium (BK) channels are among the most sensitive molecular targets of ethanol and genetic variations in the channel-forming α subunit have been nominally associated with alcohol use disorders. However, whether the action of ethanol at BK α influences the motivation to drink alcohol remains to be determined. To address this question, we first tested the effect of systemically administered BK channel modulators on voluntary alcohol consumption in C57BL/6J males. Penitrem A (blocker) exerted dose-dependent effects on moderate alcohol intake, while paxilline (blocker) and BMS-204352 (opener) were ineffective. Because pharmacological manipulations are inherently limited by non-specific effects, we then sought to investigate the behavioral relevance of ethanol's direct interaction with BK α by introducing in the mouse genome a point mutation known to render BK channels insensitive to ethanol while preserving their physiological function. The BK α K361N substitution prevented ethanol from reducing spike threshold in medial habenula neurons. However, it did not alter acute responses to ethanol in vivo, including ataxia, sedation, hypothermia, analgesia, and conditioned place preference. Furthermore, the mutation did not have reproducible effects on alcohol consumption in limited, continuous, or intermittent access home cage two-bottle choice paradigms conducted in both males and females. Notably, in contrast to previous observations made in mice missing BK channel auxiliary β subunits, the BK α K361N substitution had no significant impact on ethanol intake escalation induced by chronic intermittent alcohol vapor inhalation. It also did not affect the metabolic and locomotor consequences of chronic alcohol exposure. Altogether, these data suggest that the direct interaction of ethanol with BK α does not mediate the alcohol-related phenotypes examined here in mice.
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Affiliation(s)
- Agbonlahor Okhuarobo
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Max Kreifeldt
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Pauravi J Gandhi
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Catherine Lopez
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Briana Martinez
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Kiera Fleck
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Michal Bajo
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | | | - Alex M Dopico
- University of Tennessee Health Science Center, Department of Pharmacology, Addiction Science, and Toxicology, Memphis, TN, USA
| | - Marisa Roberto
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA
| | - Amanda J Roberts
- The Scripps Research Institute, Animals Models Core Facility, La Jolla, CA, USA
| | - Gregg E Homanics
- University of Pittsburgh, Department of Anesthesiology and Perioperative Medicine, Pittsburgh, PA, USA
| | - Candice Contet
- The Scripps Research Institute, Department of Molecular Medicine, La Jolla, CA, USA.
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11
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Dinsdale RL, Roache CE, Meredith AL. Disease-associated KCNMA1 variants decrease circadian clock robustness in channelopathy mouse models. J Gen Physiol 2023; 155:e202313357. [PMID: 37728576 PMCID: PMC10510740 DOI: 10.1085/jgp.202313357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 07/07/2023] [Accepted: 08/24/2023] [Indexed: 09/21/2023] Open
Abstract
KCNMA1 encodes the voltage- and calcium-activated K+ (BK) channel, which regulates suprachiasmatic nucleus (SCN) neuronal firing and circadian behavioral rhythms. Gain-of-function (GOF) and loss-of-function (LOF) alterations in BK channel activity disrupt circadian behavior, but the effect of human disease-associated KCNMA1 channelopathy variants has not been studied on clock function. Here, we assess circadian behavior in two GOF and one LOF mouse lines. Heterozygous Kcnma1N999S/WT and homozygous Kcnma1D434G/D434G mice are validated as GOF models of paroxysmal dyskinesia (PNKD3), but whether circadian rhythm is affected in this hypokinetic locomotor disorder is unknown. Conversely, homozygous LOF Kcnma1H444Q/H444Q mice do not demonstrate PNKD3. We assessed circadian behavior by locomotor wheel running activity. All three mouse models were rhythmic, but Kcnma1N999S/WT and Kcnma1D434G/D434G showed reduced circadian amplitude and decreased wheel activity, corroborating prior studies focused on acute motor coordination. In addition, Kcnma1D434G/D434G mice had a small decrease in period. However, the phase-shifting sensitivity for both GOF mouse lines was abnormal. Both Kcnma1N999S/WT and Kcnma1D434G/D434G mice displayed increased responses to light pulses and took fewer days to re-entrain to a new light:dark cycle. In contrast, the LOF Kcnma1H444Q/H444Q mice showed no difference in any of the circadian parameters tested. The enhanced sensitivity to phase-shifting stimuli in Kcnma1N999S/WT and Kcnma1D434G/D434G mice was similar to other Kcnma1 GOF mice. Together with previous studies, these results suggest that increasing BK channel activity decreases circadian clock robustness, without rhythm ablation.
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Affiliation(s)
- Ria L. Dinsdale
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Cooper E. Roache
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Andrea L. Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
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12
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Peng Z, Liang Y, Liu X, Shao J, Hu N, Zhang X. New insights into the mechanisms of diabetic kidney disease: Role of circadian rhythm and Bmal1. Biomed Pharmacother 2023; 166:115422. [PMID: 37660646 DOI: 10.1016/j.biopha.2023.115422] [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: 06/24/2023] [Revised: 08/30/2023] [Accepted: 08/30/2023] [Indexed: 09/05/2023] Open
Abstract
It is common for diabetic kidney disease (DKD) to be complicated by abnormal blood glucose, blood lipids, and blood pressure rhythms. Thus, it is essential to examine diagnostic and treatment plans from the perspective of circadian disruption. This brief review discusses the clinical relevance of circadian rhythms in DKD and how the core clock gene encoding brain and muscle arnt-like protein 1 (BMAL1) functions owing to the importance of circadian rhythm disruption processes, including the excretion of urinary protein and irregular blood pressure, which occur in DKD. Exploring Bmal1 and its potential mechanisms and signaling pathways in DKD following contact with Sirt1 and NF-κB is novel and important. Finally, potential pharmacological and behavioral intervention strategies for DKD circadian rhythm disturbance are outlined. This review aids in unveiling novel, potential molecular targets for DKD based on circadian rhythms.
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Affiliation(s)
- Zhimei Peng
- Department of Nephrology, The Second Clinical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China; Shenzhen Key Laboratory of Kidney Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China.
| | - Yanting Liang
- Department of Nephrology, The Second Clinical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China.
| | - Xueying Liu
- Shenzhen Key Laboratory of Kidney Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China.
| | - Jie Shao
- Department of Nephrology, The Second Clinical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China.
| | - Nan Hu
- Shenzhen Key Laboratory of Kidney Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China.
| | - Xinzhou Zhang
- Department of Nephrology, The Second Clinical College of Jinan University, Shenzhen People's Hospital, Shenzhen, China; Shenzhen Key Laboratory of Kidney Diseases, Shenzhen People's Hospital (The Second Clinical Medical College, Jinan University, The First Affiliated Hospital, Southern University of Science and Technology), Shenzhen, China.
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13
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-encoded K+ channels drive the day-night switch in the repetitive firing rates of SCN neurons. J Gen Physiol 2023; 155:e202213310. [PMID: 37516908 PMCID: PMC10373311 DOI: 10.1085/jgp.202213310] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 05/11/2023] [Accepted: 07/06/2023] [Indexed: 07/31/2023] Open
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K+) channels regulate daily oscillations in the spontaneous firing rates of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K+ conductance(s) driving these daily rhythms in the repetitive firing rates of SCN neurons, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K+ channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1-/-) or Kcnh3 (Kv12.2-/-) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1-/- and Kv12.2-/- than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1-/-, Kv12.2-/-, and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1-/- and Kv12.2-/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, the pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of the nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1-/-, Kv12.2-/-, and Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
| | - Nien-Du Yang
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Rebecca L. Mellor
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, State College, PA, USA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO, USA
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, USA
- Cardiovascular Division, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Department of Biomedical Engineering, Washington University, St. Louis, MO, USA
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14
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Peng Z, Ziros PG, Martini T, Liao XH, Stoop R, Refetoff S, Albrecht U, Sykiotis GP, Kellenberger S. ASIC1a affects hypothalamic signaling and regulates the daily rhythm of body temperature in mice. Commun Biol 2023; 6:857. [PMID: 37591947 PMCID: PMC10435469 DOI: 10.1038/s42003-023-05221-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 08/05/2023] [Indexed: 08/19/2023] Open
Abstract
The body temperature of mice is higher at night than during the day. We show here that global deletion of acid-sensing ion channel 1a (ASIC1a) results in lower body temperature during a part of the night. ASICs are pH sensors that modulate neuronal activity. The deletion of ASIC1a decreased the voluntary activity at night of mice that had access to a running wheel but did not affect their spontaneous activity. Daily rhythms of thyrotropin-releasing hormone mRNA in the hypothalamus and of thyroid-stimulating hormone β mRNA in the pituitary, and of prolactin mRNA in the hypothalamus and pituitary were suppressed in ASIC1a-/- mice. The serum thyroid hormone levels were however not significantly changed by ASIC1a deletion. Our findings indicate that ASIC1a regulates activity and signaling in the hypothalamus and pituitary. This likely leads to the observed changes in body temperature by affecting the metabolism or energy expenditure.
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Affiliation(s)
- Zhong Peng
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland
| | - Panos G Ziros
- Service of Endocrinology, Diabetology and Metabolism, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Tomaz Martini
- Department of Biology/Unit of Biochemistry, Faculty of Sciences, University of Fribourg, Fribourg, Switzerland
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, IL, USA
| | - Ron Stoop
- Center for Psychiatric Neurosciences, Hôpital de Cery, Lausanne University Hospital, Lausanne, Switzerland
| | - Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, IL, USA
- Department of Pediatrics, The University of Chicago, Chicago, IL, USA
- Committee on Genetics, The University of Chicago, Chicago, IL, USA
| | - Urs Albrecht
- Department of Biology/Unit of Biochemistry, Faculty of Sciences, University of Fribourg, Fribourg, Switzerland
| | - Gerasimos P Sykiotis
- Service of Endocrinology, Diabetology and Metabolism, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Stephan Kellenberger
- Department of Biomedical Sciences, University of Lausanne, Lausanne, Switzerland.
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15
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Wang S, Khan S, Nabi G, Li HY. Circadian rhythm as a key player in cancer progression as well as a therapeutic target in HER2-positive advanced gastric cancer treatment. Front Oncol 2023; 13:1240676. [PMID: 37503323 PMCID: PMC10369080 DOI: 10.3389/fonc.2023.1240676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 06/27/2023] [Indexed: 07/29/2023] Open
Abstract
Gastric cancer is one of the most common cancer types with less than one year prognosis in metastatic disease, which poses a huge disease burden. One of the key players in poor prognosis is human epidermal growth factor receptor 2 (HER2), which also contributes to the pathogenesis of HER2-positive advanced gastric cancer. Trastuzumab is used as first-line chemotherapy that targets the expression of HER2, however, trastuzumab resistance is an inevitable major problem. To overcome this problem, readjustment of the circadian system may play a crucial role, as dysregulation in the expression of circadian clock genes has been observed in tumors. Therefore, pharmacological modulation of clock components can be considered for better efficacy of trastuzumab. In this review, we discuss the association of circadian clock with cancer progression, development, and treatment. Metformin-based chronotherapy can disrupt BMAL1-CLOCK-PER1-HK2 axis, thereby affecting glycolysis oscillation to overcome trastuzumab resistance in HER2-positive advanced gastric cancer.
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Affiliation(s)
- Shihao Wang
- Department of Gastroenterology, The People’s Hospital of Changxing County, Huzhou, Zhejiang, China
| | - Suliman Khan
- Medical Research Center, The Second Affiliated Hospital of Zhengzhou University, Zhengzhou, China
| | - Ghulam Nabi
- Institute of Nature Conservation, Polish Academy of Sciences, Krakow, Poland
| | - Hong-Yu Li
- Department of Gastroenterology, The People’s Hospital of Changxing County, Huzhou, Zhejiang, China
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16
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Yang ND, Mellor RL, Hermanstyne TO, Nerbonne JM. Effects of NALCN-Encoded Na + Leak Currents on the Repetitive Firing Properties of SCN Neurons Depend on K +-Driven Rhythmic Changes in Input Resistance. J Neurosci 2023; 43:5132-5141. [PMID: 37339878 PMCID: PMC10342223 DOI: 10.1523/jneurosci.0182-23.2023] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 06/02/2023] [Accepted: 06/12/2023] [Indexed: 06/22/2023] Open
Abstract
Neurons in the suprachiasmatic nucleus (SCN) generate circadian changes in the rates of spontaneous action potential firing that regulate and synchronize daily rhythms in physiology and behavior. Considerable evidence suggests that daily rhythms in the repetitive firing rates (higher during the day than at night) of SCN neurons are mediated by changes in subthreshold potassium (K+) conductance(s). An alternative "bicycle" model for circadian regulation of membrane excitability in clock neurons, however, suggests that an increase in NALCN-encoded sodium (Na+) leak conductance underlies daytime increases in firing rates. The experiments reported here explored the role of Na+ leak currents in regulating daytime and nighttime repetitive firing rates in identified adult male and female mouse SCN neurons: vasoactive intestinal peptide-expressing (VIP+), neuromedin S-expressing (NMS+) and gastrin-releasing peptide-expressing (GRP+) cells. Whole-cell recordings from VIP+, NMS+, and GRP+ neurons in acute SCN slices revealed that Na+ leak current amplitudes/densities are similar during the day and at night, but have a larger impact on membrane potentials in daytime neurons. Additional experiments, using an in vivo conditional knockout approach, demonstrated that NALCN-encoded Na+ currents selectively regulate daytime repetitive firing rates of adult SCN neurons. Dynamic clamp-mediated manipulation revealed that the effects of NALCN-encoded Na+ currents on the repetitive firing rates of SCN neurons depend on K+ current-driven changes in input resistances. Together, these findings demonstrate that NALCN-encoded Na+ leak channels contribute to regulating daily rhythms in the excitability of SCN neurons by a mechanism that depends on K+ current-mediated rhythmic changes in intrinsic membrane properties.SIGNIFICANCE STATEMENT Elucidating the ionic mechanisms responsible for generating daily rhythms in the rates of spontaneous action potential firing of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals, is an important step toward understanding how the molecular clock controls circadian rhythms in physiology and behavior. While numerous studies have focused on identifying subthreshold K+ channel(s) that mediate day-night changes in the firing rates of SCN neurons, a role for Na+ leak currents has also been suggested. The results of the experiments presented here demonstrate that NALCN-encoded Na+ leak currents differentially modulate daily rhythms in the daytime/nighttime repetitive firing rates of SCN neurons as a consequence of rhythmic changes in subthreshold K+ currents.
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Affiliation(s)
- Nien-Du Yang
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110
| | | | - Tracey O Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Jeanne M Nerbonne
- Department of Biomedical Engineering, Washington University, St. Louis, Missouri 63110
- Department of Medicine, Cardiovascular Division
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
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17
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Chen G, Li Q, Webb TI, Hollywood MA, Yan J. BK channel modulation by positively charged peptides and auxiliary γ subunits mediated by the Ca2+-bowl site. J Gen Physiol 2023; 155:e202213237. [PMID: 37130264 PMCID: PMC10163825 DOI: 10.1085/jgp.202213237] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Revised: 01/12/2023] [Accepted: 04/13/2023] [Indexed: 05/04/2023] Open
Abstract
The large-conductance, Ca2+-, and voltage-activated K+ (BK) channel consists of the pore-forming α (BKα) subunit and regulatory β and γ subunits. The γ1-3 subunits facilitate BK channel activation by shifting the voltage-dependence of channel activation toward the hyperpolarization direction by about 50-150 mV in the absence of Ca2+. We previously found that the intracellular C-terminal positively charged regions of the γ subunits play important roles in BK channel modulation. In this study, we found that the intracellular C-terminal region of BKα is indispensable in BK channel modulation by the γ1 subunit. Notably, synthetic peptide mimics of the γ1-3 subunits' C-terminal positively charged regions caused 30-50 mV shifts in BKα channel voltage-gating toward the hyperpolarization direction. The cationic cell-penetrating HIV-1 Tat peptide exerted a similar BK channel-activating effect. The BK channel-activating effects of the synthetic peptides were reduced in the presence of Ca2+ and markedly ablated by both charge neutralization of the Ca2+-bowl site and high ionic strength, suggesting the involvement of electrostatic interactions. The efficacy of the γ subunits in BK channel modulation was reduced by charge neutralization of the Ca2+-bowl site. However, BK channel modulation by the γ1 subunit was little affected by high ionic strength and the positively charged peptide remained effective in BK channel modulation in the presence of the γ1 subunit. These findings identify positively charged peptides as BK channel modulators and reveal a role for the Ca2+-bowl site in BK channel modulation by positively charged peptides and the C-terminal positively charged regions of auxiliary γ subunits.
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Affiliation(s)
- Guanxing Chen
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Qin Li
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Timothy I. Webb
- The Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Mark A. Hollywood
- The Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland
| | - Jiusheng Yan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- Neuroscience and Biochemistry and Cell Biology Graduate Programs, MD Anderson UT Health Graduate School of Biomedical Sciences, Houston, TX, USA
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18
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Chapp AD, Collins AR, Driscoll KM, Behnke JE, Shan Z, Zhang L, Chen QH. Ethanol Metabolite, Acetate, Increases Excitability of the Central Nucleus of Amygdala Neurons through Activation of NMDA Receptors. ACS Chem Neurosci 2023; 14:1278-1290. [PMID: 36957993 PMCID: PMC11163875 DOI: 10.1021/acschemneuro.2c00784] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/25/2023] Open
Abstract
The central nucleus of the amygdala (CeA) is a key brain region involved in emotional and stressor responses due to its many projections to autonomic regulatory centers. It is also a primary site of action from ethanol consumption. However, the influence of active metabolites of ethanol such as acetate on the CeA neural circuitry has yet to be elucidated. Here, we investigated the effect of acetate on CeA neurons with the axon projecting to the rostral ventrolateral medulla (CeA-RVLM), as well as quantified cytosolic calcium responses in primary neuronal cultures. Whole-cell patch-clamp recordings in brain slices containing autonomic CeA-RVLM neurons revealed a dose-dependent increase in neuronal excitability in response to acetate. N-Methyl-d-aspartate receptor (NMDAR) antagonists suppressed the acetate-induced increase in CeA-RVLM neuronal excitability and memantine suppressed the direct activation of NMDAR-dependent inward currents by acetate in brain slices. We observed that acetate increased cytosolic Ca2+ in a time-dependent manner in primary neuronal cell cultures. The acetate enhancement of calcium signaling was abolished by memantine. Computational modeling of acetic acid at NMDAR/NR1 glutamatergic and glycinergic sites suggests potential active site interactions. These findings suggest that within the CeA, acetate is excitatory at least partially through activation of NMDAR, which may underlie the impact of ethanol consumption on autonomic circuitry.
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Affiliation(s)
- Andrew D Chapp
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC, 1400 Townsend Drive, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
- Department of Neuroscience, University of Minnesota, Twin Cities, 321 Church Street SE, Minneapolis, Minnesota 55455, United States
| | - Andréa R Collins
- Department of Psychiatry, University of California, San Francisco, Fresno, California 93701, United States
| | - Kyle M Driscoll
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Jessica E Behnke
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC, 1400 Townsend Drive, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC, 1400 Townsend Drive, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
| | - Li Zhang
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852, United States
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, SDC, 1400 Townsend Drive, Houghton, Michigan 49931, United States
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan 49931, United States
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19
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Stangherlin A. Ion dynamics and the regulation of circadian cellular physiology. Am J Physiol Cell Physiol 2023; 324:C632-C643. [PMID: 36689675 DOI: 10.1152/ajpcell.00378.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Circadian rhythms in physiology and behavior allow organisms to anticipate the daily environmental changes imposed by the rotation of our planet around its axis. Although these rhythms eventually manifest at the organismal level, a cellular basis for circadian rhythms has been demonstrated. Significant contributors to these cell-autonomous rhythms are daily cycles in gene expression and protein translation. However, recent data revealed cellular rhythms in other biological processes, including ionic currents, ion transport, and cytosolic ion abundance. Circadian rhythms in ion currents sustain circadian variation in action potential firing rate, which coordinates neuronal behavior and activity. Circadian regulation of metal ions abundance and dynamics is implicated in distinct cellular processes, from protein translation to membrane activity and osmotic homeostasis. In turn, studies showed that manipulating ion abundance affects the expression of core clock genes and proteins, suggestive of a close interplay. However, the relationship between gene expression cycles, ion dynamics, and cellular function is still poorly characterized. In this review, I will discuss the mechanisms that generate ion rhythms, the cellular functions they govern, and how they feed back to regulate the core clock machinery.
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Affiliation(s)
- Alessandra Stangherlin
- Faculty of Medicine and University Hospital Cologne, Cluster of Excellence Cellular Stress Responses in Aging-associated Diseases (CECAD), Institute for Mitochondrial Diseases and Ageing, University of Cologne, Cologne, Germany
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20
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Ancatén-González C, Segura I, Alvarado-Sánchez R, Chávez AE, Latorre R. Ca 2+- and Voltage-Activated K + (BK) Channels in the Nervous System: One Gene, a Myriad of Physiological Functions. Int J Mol Sci 2023; 24:3407. [PMID: 36834817 PMCID: PMC9967218 DOI: 10.3390/ijms24043407] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/18/2023] [Accepted: 01/21/2023] [Indexed: 02/11/2023] Open
Abstract
BK channels are large conductance potassium channels characterized by four pore-forming α subunits, often co-assembled with auxiliary β and γ subunits to regulate Ca2+ sensitivity, voltage dependence and gating properties. BK channels are abundantly expressed throughout the brain and in different compartments within a single neuron, including axons, synaptic terminals, dendritic arbors, and spines. Their activation produces a massive efflux of K+ ions that hyperpolarizes the cellular membrane. Together with their ability to detect changes in intracellular Ca2+ concentration, BK channels control neuronal excitability and synaptic communication through diverse mechanisms. Moreover, increasing evidence indicates that dysfunction of BK channel-mediated effects on neuronal excitability and synaptic function has been implicated in several neurological disorders, including epilepsy, fragile X syndrome, mental retardation, and autism, as well as in motor and cognitive behavior. Here, we discuss current evidence highlighting the physiological importance of this ubiquitous channel in regulating brain function and its role in the pathophysiology of different neurological disorders.
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Affiliation(s)
- Carlos Ancatén-González
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Programa de Doctorado en Ciencias, Mención Neurociencia, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Ignacio Segura
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Rosangelina Alvarado-Sánchez
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
- Doctorado en Ciencias Mención Biofísica y Biología Computacional, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Andrés E. Chávez
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
| | - Ramon Latorre
- Centro Interdisciplinario de Neurociencia de Valparaíso (CINV), Instituto de Neurociencias, Universidad de Valparaíso, Valparaíso 2340000, Chile
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21
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Hermanstyne TO, Yang ND, Granados-Fuentes D, Li X, Mellor RL, Jegla T, Herzog ED, Nerbonne JM. Kv12-Encoded K + Channels Drive the Day-Night Switch in the Repetitive Firing Rates of SCN Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526323. [PMID: 36778242 PMCID: PMC9915524 DOI: 10.1101/2023.01.30.526323] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Considerable evidence suggests that day-night rhythms in the functional expression of subthreshold potassium (K + ) channels regulate daily oscillations in the rates of spontaneous action potential firing of neurons in the suprachiasmatic nucleus (SCN), the master circadian pacemaker in mammals. The K + conductance(s) driving these daily rhythms in repetitive firing rates, however, have not been identified. To test the hypothesis that subthreshold Kv12.1/Kv12.2-encoded K + channels play a role, we obtained current-clamp recordings from SCN neurons in slices prepared from adult mice harboring targeted disruptions in the Kcnh8 (Kv12.1 -/- ) or Kcnh3 (Kv12.2 -/- ) locus. We found that mean nighttime repetitive firing rates were higher in Kv12.1 -/- and Kv12.2 -/- , than in wild type (WT), SCN neurons. In marked contrast, mean daytime repetitive firing rates were similar in Kv12.1 -/- , Kv12.2 -/- and WT SCN neurons, and the day-night difference in mean repetitive firing rates, a hallmark feature of WT SCN neurons, was eliminated in Kv12.1 -/- and Kv12.2 -/- SCN neurons. Similar results were obtained with in vivo shRNA-mediated acute knockdown of Kv12.1 or Kv12.2 in adult SCN neurons. Voltage-clamp experiments revealed that Kv12-encoded current densities in WT SCN neurons are higher at night than during the day. In addition, pharmacological block of Kv12-encoded currents increased the mean repetitive firing rate of nighttime, but not daytime, in WT SCN neurons. Dynamic clamp-mediated subtraction of modeled Kv12-encoded currents also selectively increased the mean repetitive firing rates of nighttime WT SCN neurons. Despite the elimination of nighttime decrease in the mean repetitive firing rates of SCN neurons, however, locomotor (wheel-running) activity remained rhythmic in Kv12.1 -/- , Kv12.2 -/- , Kv12.1-targeted shRNA-expressing, and Kv12.2-targeted shRNA-expressing animals.
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Affiliation(s)
- Tracey O. Hermanstyne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
| | - Nien-Du Yang
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
| | | | - Xiaofan Li
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Rebecca L. Mellor
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
| | - Timothy Jegla
- Department of Biology, The Pennsylvania State University, University Park, PA
| | - Erik D. Herzog
- Department of Biology, Washington University, St. Louis, MO
| | - Jeanne M. Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO
- Department of Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, MO
- Department of Biomedical Engineering, Washington University School of Medicine, St. Louis, MO
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22
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Park SM, Roache CE, Iffland PH, Moldenhauer HJ, Matychak KK, Plante AE, Lieberman AG, Crino PB, Meredith A. BK channel properties correlate with neurobehavioral severity in three KCNMA1-linked channelopathy mouse models. eLife 2022; 11:e77953. [PMID: 35819138 PMCID: PMC9275823 DOI: 10.7554/elife.77953] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 06/01/2022] [Indexed: 12/14/2022] Open
Abstract
KCNMA1 forms the pore of BK K+ channels, which regulate neuronal and muscle excitability. Recently, genetic screening identified heterozygous KCNMA1 variants in a subset of patients with debilitating paroxysmal non-kinesigenic dyskinesia, presenting with or without epilepsy (PNKD3). However, the relevance of KCNMA1 mutations and the basis for clinical heterogeneity in PNKD3 has not been established. Here, we evaluate the relative severity of three KCNMA1 patient variants in BK channels, neurons, and mice. In heterologous cells, BKN999S and BKD434G channels displayed gain-of-function (GOF) properties, whereas BKH444Q channels showed loss-of-function (LOF) properties. The relative degree of channel activity was BKN999S > BKD434G>WT > BKH444Q. BK currents and action potential firing were increased, and seizure thresholds decreased, in Kcnma1N999S/WT and Kcnma1D434G/WT transgenic mice but not Kcnma1H444Q/WT mice. In a novel behavioral test for paroxysmal dyskinesia, the more severely affected Kcnma1N999S/WT mice became immobile after stress. This was abrogated by acute dextroamphetamine treatment, consistent with PNKD3-affected individuals. Homozygous Kcnma1D434G/D434G mice showed similar immobility, but in contrast, homozygous Kcnma1H444Q/H444Q mice displayed hyperkinetic behavior. These data establish the relative pathogenic potential of patient alleles as N999S>D434G>H444Q and validate Kcnma1N999S/WT mice as a model for PNKD3 with increased seizure propensity.
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Affiliation(s)
- Su Mi Park
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Cooper E Roache
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Philip H Iffland
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Hans J Moldenhauer
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Katia K Matychak
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Amber E Plante
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
| | - Abby G Lieberman
- Department of Pharmacology, University of Maryland School of MedicineBaltimoreUnited States
| | - Peter B Crino
- Department of Neurology, University of Maryland School of MedicineBaltimoreUnited States
| | - Andrea Meredith
- Department of Physiology, University of Maryland School of MedicineBaltimoreUnited States
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23
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Morioka E, Kasuga Y, Kanda Y, Moritama S, Koizumi H, Yoshikawa T, Miura N, Ikeda M, Higashida H, Holmes TC, Ikeda M. Mitochondrial LETM1 drives ionic and molecular clock rhythms in circadian pacemaker neurons. Cell Rep 2022; 39:110787. [PMID: 35545046 DOI: 10.1016/j.celrep.2022.110787] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 03/14/2022] [Accepted: 04/14/2022] [Indexed: 11/18/2022] Open
Abstract
The mechanisms that generate robust ionic oscillation in circadian pacemaker neurons are under investigation. Here, we demonstrate critical functions of the mitochondrial cation antiporter leucine zipper-EF-hand-containing transmembrane protein 1 (LETM1), which exchanges K+/H+ in Drosophila and Ca2+/H+ in mammals, in circadian pacemaker neurons. Letm1 knockdown in Drosophila pacemaker neurons reduced circadian cytosolic H+ rhythms and prolonged nuclear PERIOD/TIMELESS expression rhythms and locomotor activity rhythms. In rat pacemaker neurons in the hypothalamic suprachiasmatic nucleus (SCN), circadian rhythms in cytosolic Ca2+ and Bmal1 transcription were dampened by Letm1 knockdown. Mitochondrial Ca2+ uptake peaks late during the day were also observed in rat SCN neurons following photolytic elevation of cytosolic Ca2+. Since cation transport by LETM1 is coupled to mitochondrial energy synthesis, we propose that LETM1 integrates metabolic, ionic, and molecular clock rhythms in the central clock system in both invertebrates and vertebrates.
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Affiliation(s)
- Eri Morioka
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan
| | - Yusuke Kasuga
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan
| | - Yuzuki Kanda
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan
| | - Saki Moritama
- Graduate School of Science and Engineering, University of Toyama, Gofuku, Toyama 930-8555, Japan
| | - Hayato Koizumi
- Graduate School of Innovative Life Science, University of Toyama, Gofuku, Toyama 930-8555, Japan
| | - Tomoko Yoshikawa
- Organization for International Education and Exchange, University of Toyama, Toyama 930-8555, Japan
| | - Nobuhiko Miura
- Department of Health Medicine, Yokohama University of Pharmacy, Yokohama, Kanagawa 245-0061, Japan
| | - Masaaki Ikeda
- Department of Physiology, Faculty of Medicine, Saitama Medical University, Saitama 350-0495, Japan
| | - Haruhiro Higashida
- Research Center for Child Mental Development, Kanazawa University, Ishikawa 920-8640, Japan
| | - Todd C Holmes
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Masayuki Ikeda
- Graduate School of Innovative Life Science, University of Toyama, Gofuku, Toyama 930-8555, Japan; Organization for International Education and Exchange, University of Toyama, Toyama 930-8555, Japan.
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24
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Schroder EA, Ono M, Johnson SR, Rozmus ER, Burgess DE, Esser KA, Delisle BP. The role of the cardiomyocyte circadian clocks in ion channel regulation and cardiac electrophysiology. J Physiol 2022; 600:2037-2048. [PMID: 35301719 PMCID: PMC9980729 DOI: 10.1113/jp282402] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 03/04/2022] [Indexed: 11/08/2022] Open
Abstract
Daily variations in cardiac electrophysiology and the incidence for different types of arrhythmias reflect ≈24 h changes in the environment, behaviour and internal circadian rhythms. This article focuses on studies that use animal models to separate the impact that circadian rhythms, as well as changes in the environment and behaviour, have on 24 h rhythms in heart rate and ventricular repolarization. Circadian rhythms are initiated at the cellular level by circadian clocks, transcription-translation feedback loops that cycle with a periodicity of 24 h. Several studies now show that the circadian clock in cardiomyocytes regulates the expression of cardiac ion channels by multiple mechanisms; underlies time-of-day changes in sinoatrial node excitability/intrinsic heart rate; and limits the duration of the ventricular action potential waveform. However, the 24 h rhythms in heart rate and ventricular repolarization are primarily driven by autonomic signalling. A functional role for the cardiomyocyte circadian clock appears to buffer the heart against perturbations. For example, the cardiomyocyte circadian clock limits QT-interval prolongation (especially at slower heart rates), and it may facilitate the realignment of the 24 h rhythm in heart rate to abrupt changes in the light cycle. Additional studies show that modifying rhythmic behaviours (including feeding behaviour) can dramatically impact the 24 h rhythms in heart rate and ventricular repolarization. If these mechanisms are conserved, these studies suggest that targeting endogenous circadian mechanisms in the heart, as well as modifying the timing of certain rhythmic behaviours, could emerge as therapeutic strategies to support heart function against perturbations and regulate 24 h rhythms in cardiac electrophysiology.
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Affiliation(s)
- Elizabeth A. Schroder
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298,Department of Internal Medicine, Division of Pulmonary, Critical Care and Sleep Medicine, University of Kentucky, 740 S. Limestone Street, L543, Lexington, KY 40536-0284
| | - Makoto Ono
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Sidney R. Johnson
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Ezekiel R. Rozmus
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Don E. Burgess
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
| | - Karyn A. Esser
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, FL, USA
| | - Brian P. Delisle
- Department of Physiology, University of Kentucky, 800 Rose Street, MN508, Lexington, KY 40536-0298
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25
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Liang X, Holy TE, Taghert PH. Circadian pacemaker neurons display cophasic rhythms in basal calcium level and in fast calcium fluctuations. Proc Natl Acad Sci U S A 2022; 119:e2109969119. [PMID: 35446620 PMCID: PMC9173584 DOI: 10.1073/pnas.2109969119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 03/17/2022] [Indexed: 12/02/2022] Open
Abstract
Circadian pacemaker neurons in the Drosophila brain display daily rhythms in the levels of intracellular calcium. These calcium rhythms are driven by molecular clocks and are required for normal circadian behavior. To study their biological basis, we employed genetic manipulations in conjunction with improved methods of in vivo light-sheet microscopy to measure calcium dynamics in individual pacemaker neurons over complete 24-h durations at sampling frequencies as high as 5 Hz. This technological advance unexpectedly revealed cophasic daily rhythms in basal calcium levels and in high-frequency calcium fluctuations. Further, we found that the rhythms of basal calcium levels and of fast calcium fluctuations reflect the activities of two proteins that mediate distinct forms of calcium fluxes. One is the inositol trisphosphate receptor (ITPR), a channel that mediates calcium fluxes from internal endoplasmic reticulum calcium stores, and the other is a T-type voltage-gated calcium channel, which mediates extracellular calcium influx. These results suggest that Drosophila molecular clocks regulate ITPR and T-type channels to generate two distinct but coupled rhythms in basal calcium and in fast calcium fluctuations. We propose that both internal and external calcium fluxes are essential for circadian pacemaker neurons to provide rhythmic outputs and thereby, regulate the activities of downstream brain centers.
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Affiliation(s)
- Xitong Liang
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO 63110
| | - Timothy E. Holy
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO 63110
| | - Paul H. Taghert
- Department of Neuroscience, Washington University in St. Louis, St. Louis, MO 63110
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26
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Time-restricted feeding entrains long-term behavioral changes through the IGF2-KCC2 pathway. iScience 2022; 25:104267. [PMID: 35521538 PMCID: PMC9062755 DOI: 10.1016/j.isci.2022.104267] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 10/13/2021] [Accepted: 04/13/2022] [Indexed: 02/03/2023] Open
Abstract
The suprachiasmatic nucleus (SCN) integrates light and systemic signals from peripheral tissues to coordinate physiology and behavior daily rhythms. However, the contribution that nutrients and feeding patterns provide to the SCN network regulation remains controversial. Here, we found that time-restricted feeding (TRF) in ZT0-4 (Zeitgeber Time) generates a robust and long-term shift in locomotor behavior and increased wakefulness. Intracellular Ca2+ signals in SCN GABAergic neurons of freely moving mice showed significant activation after ZT0-4 TRF treatment. Furthermore, RNA-seq profiling of SCN showed that TRF during ZT0-4 increased Insulin-like Growth Factor 2 (Igf2) expression and dysregulated ion transporters, including the downregulation of Kcc2. SCN neuron-specific loss of function of Kcc2 amplified ZT0-4 TRF induced aftereffect. Moreover, overexpression of IGF2 in SCN GABAergic neurons extended the locomotion range, mirroring the TRF aftereffect. In summary, our study showed that the IGF2-KCC2 pathway plays an important role for TRF induced behavior changes.
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27
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Chen G, Li Q, Yan J. The leucine-rich repeat domains of BK channel auxiliary γ subunits regulate their expression, trafficking, and channel-modulation functions. J Biol Chem 2022; 298:101664. [PMID: 35104503 PMCID: PMC8892010 DOI: 10.1016/j.jbc.2022.101664] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/16/2022] [Accepted: 01/26/2022] [Indexed: 11/25/2022] Open
Abstract
As high-conductance calcium- and voltage-dependent potassium channels, BK channels consist of pore-forming, voltage-, and Ca2+-sensing α and auxiliary subunits. The leucine-rich repeat (LRR) domain-containing auxiliary γ subunits potently modulate the voltage dependence of BK channel activation. Despite their dominant size in whole protein masses, the function of the LRR domain in BK channel γ subunits is unknown. We here investigated the function of these LRR domains in BK channel modulation by the auxiliary γ1-3 (LRRC26, LRRC52, and LRRC55) subunits. Using cell surface protein immunoprecipitation, we validated the predicted extracellular localization of the LRR domains. We then refined the structural models of mature proteins on the membrane via molecular dynamic simulations. By replacement of the LRR domain with extracellular regions or domains of non-LRR proteins, we found that the LRR domain is nonessential for the maximal channel-gating modulatory effect but is necessary for the all-or-none phenomenon of BK channel modulation by the γ1 subunit. Mutational and enzymatic blockade of N-glycosylation in the γ1-3 subunits resulted in a reduction or loss of BK channel modulation by γ subunits. Finally, by analyzing their expression in whole cells and on the plasma membrane, we found that blockade of N-glycosylation drastically reduced total expression of the γ2 subunit and the cell surface expression of the γ1 and γ3 subunits. We conclude that the LRR domains play key roles in the regulation of the expression, cell surface trafficking, and channel-modulation functions of the BK channel γ subunits.
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Affiliation(s)
- Guanxing Chen
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Qin Li
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Jiusheng Yan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA; Graduate Programs of Neuroscience and Biochemistry and Cell Biology, The University of Texas MD Anderson Cancer Center UT Health Graduate School of Biomedical Sciences, Houston, Texas, USA.
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28
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Shah KR, Guan X, Yan J. Structural and Functional Coupling of Calcium-Activated BK Channels and Calcium-Permeable Channels Within Nanodomain Signaling Complexes. Front Physiol 2022; 12:796540. [PMID: 35095560 PMCID: PMC8795833 DOI: 10.3389/fphys.2021.796540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Accepted: 12/28/2021] [Indexed: 11/13/2022] Open
Abstract
Biochemical and functional studies of ion channels have shown that many of these integral membrane proteins form macromolecular signaling complexes by physically associating with many other proteins. These macromolecular signaling complexes ensure specificity and proper rates of signal transduction. The large-conductance, Ca2+-activated K+ (BK) channel is dually activated by membrane depolarization and increases in intracellular free Ca2+ ([Ca2+]i). The activation of BK channels results in a large K+ efflux and, consequently, rapid membrane repolarization and closing of the voltage-dependent Ca2+-permeable channels to limit further increases in [Ca2+]i. Therefore, BK channel-mediated K+ signaling is a negative feedback regulator of both membrane potential and [Ca2+]i and plays important roles in many physiological processes and diseases. However, the BK channel formed by the pore-forming and voltage- and Ca2+-sensing α subunit alone requires high [Ca2+]i levels for channel activation under physiological voltage conditions. Thus, most native BK channels are believed to co-localize with Ca2+-permeable channels within nanodomains (a few tens of nanometers in distance) to detect high levels of [Ca2+]i around the open pores of Ca2+-permeable channels. Over the last two decades, advancement in research on the BK channel’s coupling with Ca2+-permeable channels including recent reports involving NMDA receptors demonstrate exemplary models of nanodomain structural and functional coupling among ion channels for efficient signal transduction and negative feedback regulation. We hereby review our current understanding regarding the structural and functional coupling of BK channels with different Ca2+-permeable channels.
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Affiliation(s)
- Kunal R. Shah
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Xin Guan
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
| | - Jiusheng Yan
- Department of Anesthesiology & Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Neuroscience Program, Graduate School of Biomedical Sciences, UT Health, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- Biochemistry and Cell Biology Program, Graduate School of Biomedical Sciences, UT Health, The University of Texas MD Anderson Cancer Center, Houston, TX, United States
- *Correspondence: Jiusheng Yan,
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29
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Imaizumi Y. Reciprocal Relationship between Ca 2+ Signaling and Ca 2+-Gated Ion Channels as a Potential Target for Drug Discovery. Biol Pharm Bull 2022; 45:1-18. [PMID: 34980771 DOI: 10.1248/bpb.b21-00896] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cellular Ca2+ signaling functions as one of the most common second messengers of various signal transduction pathways in cells and mediates a number of physiological roles in a cell-type dependent manner. Ca2+ signaling also regulates more general and fundamental cellular activities, including cell proliferation and apoptosis. Among ion channels, Ca2+-permeable channels in the plasma membrane as well as endo- and sarcoplasmic reticulum membranes play important roles in Ca2+ signaling by directly contributing to the influx of Ca2+ from extracellular spaces or its release from storage sites, respectively. Furthermore, Ca2+-gated ion channels in the plasma membrane often crosstalk reciprocally with Ca2+ signals and are central to the regulation of cellular functions. This review focuses on the physiological and pharmacological impact of i) Ca2+-gated ion channels as an apparatus for the conversion of cellular Ca2+ signals to intercellularly propagative electrical signals and ii) the opposite feedback regulation of Ca2+ signaling by Ca2+-gated ion channel activities in excitable and non-excitable cells.
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Affiliation(s)
- Yuji Imaizumi
- Department of Molecular and Cellular Pharmacology, Graduate School of Pharmaceutical Sciences, Nagoya City University
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30
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González-Cota AL, Santana-Calvo C, Servín-Vences R, Orta G, Balderas E. Regulatory mechanisms of mitochondrial BK Ca channels. Channels (Austin) 2021; 15:424-437. [PMID: 33955332 PMCID: PMC8117780 DOI: 10.1080/19336950.2021.1919463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/05/2021] [Accepted: 04/05/2021] [Indexed: 02/06/2023] Open
Abstract
The mitochondrial BKCa channel (mitoBKCa) is a splice variant of plasma membrane BKCa (Maxi-K, BKCa, Slo1, KCa1.1). While a high-resolution structure of mitoBKCa is not available yet, functional and structural studies of the plasma membrane BKCa have provided important clues on the gating of the channel by voltage and Ca2+, as well as the interaction with auxiliary subunits. To date, we know that the control of expression of mitoBKCa, targeting and voltage-sensitivity strongly depends on its association with its regulatory β1-subunit, which overall participate in the control of mitochondrial Ca2+-overload in cardiac myocytes. Moreover, novel regulatory mechanisms of mitoBKCa such as β-subunits and amyloid-β have recently been proposed. However, major basic questions including how the regulatory BKCa-β1-subunit reaches mitochondria and the mechanism through which amyloid-β impairs mitoBKCa channel function remain to be addressed.
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Affiliation(s)
- Ana L. González-Cota
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM. Av. Universidad 2001, Cuernavaca, Morelos, México
| | - Carmen Santana-Calvo
- Instituto Gulbenkian de Ciência. Rua da Quinta Grande 6, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica, Universida de Nova de Lisboa. Av. da República, Oeiras, Portugal
| | - Rocío Servín-Vences
- Department of Neuroscience, The Scripps Research Institute. 10550 North Torrey Pines Road, La Jolla, CA, USA
| | - Gerardo Orta
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, UNAM. Av. Universidad 2001, Cuernavaca, Morelos, México
| | - Enrique Balderas
- Nora Eccles Harrison Cardiovascular Research & Training Institute, University of Utah, Salt Lake City, UT, USA
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31
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Sanghvi S, Szteyn K, Ponnalagu D, Sridharan D, Lam A, Hansra I, Chaudhury A, Majumdar U, Kohut AR, Rao SG, Khan M, Garg V, Singh H. Inhibition of BK Ca channels protects neonatal hearts against myocardial ischemia and reperfusion injury.. [DOI: 10.1101/2021.11.02.466585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
AbstractBKCa channels are large-conductance calcium and voltage-activated potassium channels that are heterogeneously expressed in a wide array of cells. Activation of BKCa channels present in mitochondria of adult ventricular cardiomyocytes is implicated in cardioprotection against ischemia-reperfusion (IR) injury. However, the BKCa channel’s activity has never been detected in the plasma membrane of adult ventricular cardiomyocytes. In this study, we report the presence of the BKCa channel in the plasma membrane and mitochondria of neonatal murine and rodent cardiomyocytes which protects the heart on inhibition but not activation. Furthermore, K+ currents measured in neonatal cardiomyocyte (NCM) was sensitive to iberiotoxin (IbTx), suggesting the presence of BKCa channels in the plasma membrane. Neonatal hearts subjected to IR when post-conditioned with NS1619 during reoxygenation increased the myocardial infarction whereas IbTx reduced the infarct size. In agreement, isolated NCM also presented increased apoptosis on treatment with NS1619 during hypoxia and reoxygenation, whereas IbTx reduced TUNEL positive cells. In NCMs, activation of BKCa channels increased the intracellular reactive oxygen species post HR injury. Electrophysiological characterization of NCMs indicated that NS1619 increased the beat period, field, and action potential duration, and decreased the conduction velocity and spike amplitude. In contrast, IbTx had no impact on the electrophysiological properties of NCMs. Taken together, our data established that inhibition of plasma membrane BKCa channels in the NCM protects neonatal heart/cardiomyocytes from IR injury. Furthermore, the functional disparity observed towards the cardioprotective activity of BKCa channels in adults compared to neonatal heart could be attributed to their differential localization.
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32
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McNally BA, Plante AE, Meredith AL. Contributions of Ca V1.3 Channels to Ca 2+ Current and Ca 2+-Activated BK Current in the Suprachiasmatic Nucleus. Front Physiol 2021; 12:737291. [PMID: 34650447 PMCID: PMC8505962 DOI: 10.3389/fphys.2021.737291] [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: 07/06/2021] [Accepted: 08/30/2021] [Indexed: 11/29/2022] Open
Abstract
Daily regulation of Ca2+– and voltage-activated BK K+ channel activity is required for action potential rhythmicity in the suprachiasmatic nucleus (SCN) of the hypothalamus, the brain's circadian clock. In SCN neurons, BK activation is dependent upon multiple types of Ca2+ channels in a circadian manner. Daytime BK current predominantly requires Ca2+ influx through L-type Ca2+ channels (LTCCs), a time when BK channels are closely coupled with their Ca2+ source. Here we show that daytime BK current is resistant to the Ca2+ chelator BAPTA. However, at night when LTCCs contribute little to BK activation, BK current decreases by a third in BAPTA compared to control EGTA conditions. In phase with this time-of-day specific effect on BK current activation, LTCC current is larger during the day. The specific Ca2+ channel subtypes underlying the LTCC current in SCN, as well as the subtypes contributing the Ca2+ influx relevant for BK current activation, have not been identified. SCN neurons express two LTCC subtypes, CaV1.2 and CaV1.3. While a role for CaV1.2 channels has been identified during the night, CaV1.3 channel modulation has also been suggested to contribute to daytime SCN action potential activity, as well as subthreshold Ca2+ oscillations. Here we characterize the role of CaV1.3 channels in LTCC and BK current activation in SCN neurons using a global deletion of CACNA1D in mouse (CaV1.3 KO). CaV1.3 KO SCN neurons had a 50% reduction in the daytime LTCC current, but not total Ca2+ current, with no difference in Ca2+ current levels at night. During the day, CaV1.3 KO neurons exhibited oscillations in membrane potential, and most neurons, although not all, also had BK currents. Changes in BK current activation were only detectable at the highest voltage tested. These data show that while CaV1.3 channels contribute to the daytime Ca2+ current, this does not translate into a major effect on the daytime BK current. These data suggest that BK current activation does not absolutely require CaV1.3 channels and may therefore also depend on other LTCC subtypes, such as CaV1.2.
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Affiliation(s)
- Beth A McNally
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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33
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Vouga AG, Rockman ME, Yan J, Jacobson MA, Rothberg BS. State-dependent inhibition of BK channels by the opioid agonist loperamide. J Gen Physiol 2021; 153:212539. [PMID: 34357374 PMCID: PMC8352719 DOI: 10.1085/jgp.202012834] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/19/2021] [Accepted: 07/08/2021] [Indexed: 12/20/2022] Open
Abstract
Large-conductance Ca2+-activated K+ (BK) channels control a range of physiological functions, and their dysfunction is linked to human disease. We have found that the widely used drug loperamide (LOP) can inhibit activity of BK channels composed of either α-subunits (BKα channels) or α-subunits plus the auxiliary γ1-subunit (BKα/γ1 channels), and here we analyze the molecular mechanism of LOP action. LOP applied at the cytosolic side of the membrane rapidly and reversibly inhibited BK current, an effect that appeared as a decay in voltage-activated BK currents. The apparent affinity for LOP decreased with hyperpolarization in a manner consistent with LOP behaving as an inhibitor of open, activated channels. Increasing LOP concentration reduced the half-maximal activation voltage, consistent with relative stabilization of the LOP-inhibited open state. Single-channel recordings revealed that LOP did not reduce unitary BK channel current, but instead decreased BK channel open probability and mean open times. LOP elicited use-dependent inhibition, in which trains of brief depolarizing steps lead to accumulated reduction of BK current, whereas single brief depolarizing steps do not. The principal effects of LOP on BK channel gating are described by a mechanism in which LOP acts as a state-dependent pore blocker. Our results suggest that therapeutic doses of LOP may act in part by inhibiting K+ efflux through intestinal BK channels.
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Affiliation(s)
- Alexandre G Vouga
- Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA
| | - Michael E Rockman
- Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA
| | - Jiusheng Yan
- Department of Anesthesiology and Perioperative Medicine, The University of Texas MD Anderson Cancer Center, Houston, TX
| | - Marlene A Jacobson
- Moulder Center for Drug Discovery Research, Temple University School of Pharmacy, Philadelphia PA
| | - Brad S Rothberg
- Department of Medical Genetics and Molecular Biochemistry, Temple University Lewis Katz School of Medicine, Philadelphia, PA
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34
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Abstract
K+ channels enable potassium to flow across the membrane with great selectivity. There are four K+ channel families: voltage-gated K (Kv), calcium-activated (KCa), inwardly rectifying K (Kir), and two-pore domain potassium (K2P) channels. All four K+ channels are formed by subunits assembling into a classic tetrameric (4x1P = 4P for the Kv, KCa, and Kir channels) or tetramer-like (2x2P = 4P for the K2P channels) architecture. These subunits can either be the same (homomers) or different (heteromers), conferring great diversity to these channels. They share a highly conserved selectivity filter within the pore but show different gating mechanisms adapted for their function. K+ channels play essential roles in controlling neuronal excitability by shaping action potentials, influencing the resting membrane potential, and responding to diverse physicochemical stimuli, such as a voltage change (Kv), intracellular calcium oscillations (KCa), cellular mediators (Kir), or temperature (K2P).
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35
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Plante AE, Whitt JP, Meredith AL. BK channel activation by L-type Ca 2+ channels Ca V1.2 and Ca V1.3 during the subthreshold phase of an action potential. J Neurophysiol 2021; 126:427-439. [PMID: 34191630 DOI: 10.1152/jn.00089.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mammalian circadian (24 h) rhythms are timed by the pattern of spontaneous action potential firing in the suprachiasmatic nucleus (SCN). This oscillation in firing is produced through circadian regulation of several membrane currents, including large-conductance Ca2+- and voltage-activated K+ (BK) and L-type Ca2+ channel (LTCC) currents. During the day steady-state BK currents depend mostly on LTCCs for activation, whereas at night they depend predominantly on ryanodine receptors (RyRs). However, the contribution of these Ca2+ channels to BK channel activation during action potential firing has not been thoroughly investigated. In this study, we used a pharmacological approach to determine that both LTCCs and RyRs contribute to the baseline membrane potential of SCN action potential waveforms, as well as action potential-evoked BK current, during the day and night, respectively. Since the baseline membrane potential is a major determinant of circadian firing rate, we focused on the LTCCs contributing to low voltage activation of BK channels during the subthreshold phase. For these experiments, two LTCC subtypes found in SCN (CaV1.2 and CaV1.3) were coexpressed with BK channels in heterologous cells, where their differential contributions could be separately measured. CaV1.3 channels produced currents that were shifted to more hyperpolarized potentials compared with CaV1.2, resulting in increased subthreshold Ca2+ and BK currents during an action potential command. These results show that although multiple Ca2+ sources in SCN can contribute to the activation of BK current during an action potential, specific BK-CaV1.3 partnerships may optimize the subthreshold BK current activation that is critical for firing rate regulation.NEW & NOTEWORTHY BK K+ channels are important regulators of firing. Although Ca2+ channels are required for their activation in excitable cells, it is not well understood how BK channels activate using these Ca2+ sources during an action potential. This study demonstrates the differences in BK current activated by CaV1.2 and CaV1.3 channels in clock neurons and heterologous cells. The results define how specific ion channel partnerships can be engaged during distinct phases of the action potential.
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Affiliation(s)
- Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Joshua P Whitt
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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Buijink MR, Michel S. A multi-level assessment of the bidirectional relationship between aging and the circadian clock. J Neurochem 2021; 157:73-94. [PMID: 33370457 PMCID: PMC8048448 DOI: 10.1111/jnc.15286] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/23/2020] [Accepted: 12/23/2020] [Indexed: 12/15/2022]
Abstract
The daily temporal order of physiological processes and behavior contribute to the wellbeing of many organisms including humans. The central circadian clock, which coordinates the timing within our body, is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Like in other parts of the brain, aging impairs the SCN function, which in turn promotes the development and progression of aging-related diseases. We here review the impact of aging on the different levels of the circadian clock machinery-from molecules to organs-with a focus on the role of the SCN. We find that the molecular clock is less effected by aging compared to other cellular components of the clock. Proper rhythmic regulation of intracellular signaling, ion channels and neuronal excitability of SCN neurons are greatly disturbed in aging. This suggests a disconnection between the molecular clock and the electrophysiology of these cells. The neuronal network of the SCN is able to compensate for some of these cellular deficits. However, it still results in a clear reduction in the amplitude of the SCN electrical rhythm, suggesting a weakening of the output timing signal. Consequently, other brain areas and organs not only show aging-related deficits in their own local clocks, but also receive a weaker systemic timing signal. The negative spiral completes with the weakening of positive feedback from the periphery to the SCN. Consequently, chronotherapeutic interventions should aim at strengthening overall synchrony in the circadian system using life-style and/or pharmacological approaches.
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Affiliation(s)
- M. Renate Buijink
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
| | - Stephan Michel
- Department of Cellular and Chemical BiologyLaboratory for NeurophysiologyLeiden University Medical CenterLeidenthe Netherlands
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Ruiz D, Bajwa ST, Vanani N, Bajwa TA, Cavanaugh DJ. Slowpoke functions in circadian output cells to regulate rest:activity rhythms. PLoS One 2021; 16:e0249215. [PMID: 33765072 PMCID: PMC7993846 DOI: 10.1371/journal.pone.0249215] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 03/14/2021] [Indexed: 01/31/2023] Open
Abstract
The circadian system produces ~24-hr oscillations in behavioral and physiological processes to ensure that they occur at optimal times of day and in the correct temporal order. At its core, the circadian system is composed of dedicated central clock neurons that keep time through a cell-autonomous molecular clock. To produce rhythmic behaviors, time-of-day information generated by clock neurons must be transmitted across output pathways to regulate the downstream neuronal populations that control the relevant behaviors. An understanding of the manner through which the circadian system enacts behavioral rhythms therefore requires the identification of the cells and molecules that make up the output pathways. To that end, we recently characterized the Drosophila pars intercerebralis (PI) as a major circadian output center that lies downstream of central clock neurons in a circuit controlling rest:activity rhythms. We have conducted single-cell RNA sequencing (scRNAseq) to identify potential circadian output genes expressed by PI cells, and used cell-specific RNA interference (RNAi) to knock down expression of ~40 of these candidate genes selectively within subsets of PI cells. We demonstrate that knockdown of the slowpoke (slo) potassium channel in PI cells reliably decreases circadian rest:activity rhythm strength. Interestingly, slo mutants have previously been shown to have aberrant rest:activity rhythms, in part due to a necessary function of slo within central clock cells. However, rescue of slo in all clock cells does not fully reestablish behavioral rhythms, indicating that expression in non-clock neurons is also necessary. Our results demonstrate that slo exerts its effects in multiple components of the circadian circuit, including PI output cells in addition to clock neurons, and we hypothesize that it does so by contributing to the generation of daily neuronal activity rhythms that allow for the propagation of circadian information throughout output circuits.
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Affiliation(s)
- Daniela Ruiz
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Saffia T. Bajwa
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Naisarg Vanani
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Tanvir A. Bajwa
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Daniel J. Cavanaugh
- Department of Biology, Loyola University Chicago, Chicago, Illinois, United States of America
- * E-mail:
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Selezneva A, Yoshida M, Gibb A, Willis D. Nuclear BK channels regulate CREB phosphorylation in RAW264.7 macrophages. Pharmacol Rep 2021; 73:881-890. [PMID: 33713314 PMCID: PMC8180476 DOI: 10.1007/s43440-021-00229-z] [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: 08/14/2020] [Revised: 01/24/2021] [Accepted: 02/01/2021] [Indexed: 01/24/2023]
Abstract
BACKGROUND Macrophages are important cells of the innate immune system and contribute to a variety of physiological and pathophysiological responses. Monovalent and divalent ion channels have been studied in macrophage function, and while much research is still required, a role for these channels is beginning to emerge in macrophages. In addition to the plasma membrane, ion channels are also found in intracellular membranes including mitochondrial, lysosomal and nuclear membranes. While studying the function of plasma membrane located large conductance voltage- and calcium-activated potassium channels (BK channels) in a macrophage cell line RAW264.7, we became aware of the expression of these ion channels in other cellular locations. METHODS Immunofluorescence and Western blot analysis were used to identify the expression of BK channels. To demonstrate a functional role for the nuclear located channel, we investigated the effect of the lipid soluble BK channel inhibitor paxilline on CREB phosphorylation. RESULTS Treatment of resting macrophages with paxilline resulted in increased CREB phosphorylation. To confirm a role for nuclear BK channels, these experiments were repeated in isolated nuclei and similar results were found. Ca2+ and calmodulin-dependent kinases (CaMK) have been demonstrated to regulate CREB phosphorylation. Inhibition of CaMKII and CaMKIV resulted in the reversal of paxilline-induced CREB phosphorylation. CONCLUSIONS These results suggest that nuclear BK channels regulate CREB phosphorylation in macrophages. Nuclear located ion channels may therefore be part of novel signalling pathways in macrophages and should be taken into account when studying the role of ion channels in these and other cells.
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Affiliation(s)
- Anna Selezneva
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Minae Yoshida
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Alasdair Gibb
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK
| | - Dean Willis
- Department of Neuroscience, Physiology and Pharmacology, University College London, Gower Street, London, WC1E 6BT, UK.
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BK Channel Regulation of Afterpotentials and Burst Firing in Cerebellar Purkinje Neurons. J Neurosci 2021; 41:2854-2869. [PMID: 33593855 DOI: 10.1523/jneurosci.0192-20.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 01/13/2021] [Accepted: 02/05/2021] [Indexed: 11/21/2022] Open
Abstract
BK calcium-activated potassium channels have complex kinetics because they are activated by both voltage and cytoplasmic calcium. The timing of BK activation and deactivation during action potentials determines their functional role in regulating firing patterns but is difficult to predict a priori. We used action potential clamp to characterize the kinetics of voltage-dependent calcium current and BK current during action potentials in Purkinje neurons from mice of both sexes, using acutely dissociated neurons that enabled rapid voltage clamp at 37°C. With both depolarizing voltage steps and action potential waveforms, BK current was entirely dependent on calcium entry through voltage-dependent calcium channels. With voltage steps, BK current greatly outweighed the triggering calcium current, with only a brief, small net inward calcium current before Ca-activated BK current dominated the total Ca-dependent current. During action potential waveforms, although BK current activated with only a short (∼100 μs) delay after calcium current, the two currents were largely separated, with calcium current flowing during the falling phase of the action potential and most BK current flowing over several milliseconds after repolarization. Step depolarizations activated both an iberiotoxin-sensitive BK component with rapid activation and deactivation kinetics and a slower-gating iberiotoxin-resistant component. During action potential firing, however, almost all BK current came from the faster-gating iberiotoxin-sensitive channels, even during bursts of action potentials. Inhibiting BK current had little effect on action potential width or a fast afterhyperpolarization but converted a medium afterhyperpolarization to an afterdepolarization and could convert tonic firing of single action potentials to burst firing.SIGNIFICANCE STATEMENT BK calcium-activated potassium channels are widely expressed in central neurons. Altered function of BK channels is associated with epilepsy and other neuronal disorders, including cerebellar ataxia. The functional role of BK in regulating neuronal firing patterns is highly dependent on the context of other channels and varies widely among different types of neurons. Most commonly, BK channels are activated during action potentials and help produce a fast afterhyperpolarization. We find that in Purkinje neurons BK current flows primarily after the fast afterhyperpolarization and helps to prevent a later afterdepolarization from producing rapid burst firing, enabling typical regular tonic firing.
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Affiliation(s)
- Ravi Allada
- From the Department of Neurobiology, Northwestern University, Evanston (R.A.), and the Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago (J.B.) - both in Illinois
| | - Joseph Bass
- From the Department of Neurobiology, Northwestern University, Evanston (R.A.), and the Department of Medicine, Division of Endocrinology, Metabolism, and Molecular Medicine, Feinberg School of Medicine, Northwestern University, Chicago (J.B.) - both in Illinois
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Lee N, Lim BH, Lee KS, Shin J, Pagire HS, Pagire SH, Ahn JH, Lee SW, Kang TM, Park CS. Identification and Characterization of a Novel Large-Conductance Calcium-Activated Potassium Channel Activator, CTIBD, and Its Relaxation Effect on Urinary Bladder Smooth Muscle. Mol Pharmacol 2020; 99:114-124. [PMID: 33268552 DOI: 10.1124/molpharm.120.000106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 11/11/2020] [Indexed: 12/14/2022] Open
Abstract
The large-conductance calcium-activated potassium channel (BKCa channel) is expressed on various tissues and is involved in smooth muscle relaxation. The channel is highly expressed on urinary bladder smooth muscle cells and regulates the repolarization phase of the spontaneous action potentials that control muscle contraction. To discover novel chemical activators of the BKCa channel, we screened a chemical library containing 8364 chemical compounds using a cell-based fluorescence assay. A chemical compound containing an isoxazolyl benzene skeleton (compound 1) was identified as a potent activator of the BKCa channel and was structurally optimized through a structure-activity relationship study to obtain 4-(4-(4-chlorophenyl)-3-(trifluoromethyl)isoxazol-5-yl)benzene-1,3-diol (CTIBD). When CTIBD was applied to the treated extracellular side of the channel, the conductance-voltage relationship of the channel shifted toward a negative value, and the maximum conductance increased in a concentration-dependent manner. CTIBD altered the gating kinetics of the channel by dramatically slowing channel closing without effecting channel opening. The effects of CTIBD on bladder muscle relaxation and micturition function were tested in rat tissue and in vivo. CTIBD concentration-dependently reduced acetylcholine-induced contraction of urinary bladder smooth muscle strips. In an acetic acid-induced overactive bladder (OAB) model, intraperitoneal injection of 20 mg/kg CTIBD effectively restored frequent voiding contraction and lowered voiding volume without affecting other bladder function parameters. Thus, our results indicate that CTIBD and its derivatives are novel chemical activators of the bladder BKCa channel and potential candidates for OAB therapeutics. SIGNIFICANCE STATEMENT: The novel BKCa channel activator CTIBD was identified and characterized in this study. CTIBD directly activates the BKCa channel and relaxes urinary bladder smooth muscle of rat, so CTIBD can be a potential candidate for overactive bladder therapeutics.
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Affiliation(s)
- Narasaem Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Bong Hee Lim
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Kyu-Sung Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Jimin Shin
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Haushabhau S Pagire
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Suvarna H Pagire
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Jin Hee Ahn
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Sung Won Lee
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Tong Mook Kang
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
| | - Chul-Seung Park
- School of Life Sciences, Center for AI-applied High Efficiency Drug Discovery and Integrated Institute of Biomedical Research (N.L., C.-S.P.) and Department of Chemistry (H.S.P., S.H.P., J.H.A.), Gwangju Institute of Science and Technology (GIST), Gwangju, South Korea; Department of Urology, Samsung Medical Center, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Seoul, South Korea (B.H.L., K.-S.L., J.S., S.W.L.); and Department of Physiology, Sungkyunkwan University School of Medicine, Suwon, South Korea (T.M.K.)
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Abstract
Melatonin (Mel) promotes sleep through G protein-coupled receptors. However, the downstream molecular target(s) is unknown. We identified the Caenorhabditis elegans BK channel SLO-1 as a molecular target of the Mel receptor PCDR-1-. Knockout of pcdr-1, slo-1, or homt-1 (a gene required for Mel synthesis) causes substantially increased neurotransmitter release and shortened sleep duration, and these effects are nonadditive in double knockouts. Exogenous Mel inhibits neurotransmitter release and promotes sleep in wild-type (WT) but not pcdr-1 and slo-1 mutants. In a heterologous expression system, Mel activates the human BK channel (hSlo1) in a membrane-delimited manner in the presence of the Mel receptor MT1 but not MT2 A peptide acting to release free Gβγ also activates hSlo1 in a MT1-dependent and membrane-delimited manner, whereas a Gβλ inhibitor abolishes the stimulating effect of Mel. Our results suggest that Mel promotes sleep by activating the BK channel through a specific Mel receptor and Gβλ.
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Szteyn K, Singh H. BK Ca Channels as Targets for Cardioprotection. Antioxidants (Basel) 2020; 9:antiox9080760. [PMID: 32824463 PMCID: PMC7463653 DOI: 10.3390/antiox9080760] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/09/2020] [Accepted: 08/13/2020] [Indexed: 12/16/2022] Open
Abstract
The large-conductance calcium- and voltage-activated K+ channel (BKCa) are encoded by the Kcnma1 gene. They are ubiquitously expressed in neuronal, smooth muscle, astrocytes, and neuroendocrine cells where they are known to play an important role in physiological and pathological processes. They are usually localized to the plasma membrane of the majority of the cells with an exception of adult cardiomyocytes, where BKCa is known to localize to mitochondria. BKCa channels couple calcium and voltage responses in the cell, which places them as unique targets for a rapid physiological response. The expression and activity of BKCa have been linked to several cardiovascular, muscular, and neurological defects, making them a key therapeutic target. Specifically in the heart muscle, pharmacological and genetic activation of BKCa channels protect the heart from ischemia-reperfusion injury and also facilitate cardioprotection rendered by ischemic preconditioning. The mechanism involved in cardioprotection is assigned to the modulation of mitochondrial functions, such as regulation of mitochondrial calcium, reactive oxygen species, and membrane potential. Here, we review the progress made on BKCa channels and cardioprotection and explore their potential roles as therapeutic targets for preventing acute myocardial infarction.
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Estrogen-dependent MicroRNA-504 Expression and Related Baroreflex Afferent Neuroexcitation via Negative Regulation on KCNMB4 and KCa1.1 β4-subunit Expression. Neuroscience 2020; 442:168-182. [DOI: 10.1016/j.neuroscience.2020.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 07/01/2020] [Accepted: 07/01/2020] [Indexed: 11/21/2022]
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Wintler T, Schoch H, Frank M, Peixoto L. Sleep, brain development, and autism spectrum disorders: Insights from animal models. J Neurosci Res 2020; 98:1137-1149. [PMID: 32215963 PMCID: PMC7199437 DOI: 10.1002/jnr.24619] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 02/07/2020] [Accepted: 02/29/2020] [Indexed: 01/28/2023]
Abstract
Sleep is an evolutionarily conserved and powerful drive, although its complete functions are still unknown. One possible function of sleep is that it promotes brain development. The amount of sleep is greatest during ages when the brain is rapidly developing, and sleep has been shown to influence critical period plasticity. This supports a role for sleep in brain development and suggests that abnormal sleep in early life may lead to abnormal development. Autism spectrum disorder (ASD) is the most prevalent neurodevelopmental disorder in the United States. It is estimated that insomnia affects 44%-86% of the ASD population, predicting the severity of ASD core symptoms and associated behavioral problems. Sleep problems impact the quality of life of both ASD individuals and their caregivers, thus it is important to understand why they are so prevalent. In this review, we explore the role of sleep in early life as a causal factor in ASD. First, we review fundamental steps in mammalian sleep ontogeny and regulation and how sleep influences brain development. Next, we summarize current knowledge gained from studying sleep in animal models of ASD. Ultimately, our goal is to highlight the importance of understanding the role of sleep in brain development and the use of animal models to provide mechanistic insight into the origin of sleep problems in ASD.
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Affiliation(s)
- Taylor Wintler
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Hannah Schoch
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Marcos Frank
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
| | - Lucia Peixoto
- Washington State University Elson S Floyd College of Medicine, Biomedical Sciences Spokane, WA, 99202USA
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46
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Abstract
Ca2+- and voltage-gated K+ channels of large conductance (BK channels) are expressed in a diverse variety of both excitable and inexcitable cells, with functional properties presumably uniquely calibrated for the cells in which they are found. Although some diversity in BK channel function, localization, and regulation apparently arises from cell-specific alternative splice variants of the single pore-forming α subunit ( KCa1.1, Kcnma1, Slo1) gene, two families of regulatory subunits, β and γ, define BK channels that span a diverse range of functional properties. We are just beginning to unravel the cell-specific, physiological roles served by BK channels of different subunit composition.
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Affiliation(s)
- Vivian Gonzalez-Perez
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
| | - Christopher J Lingle
- Department of Anesthesiology, Washington University School of Medicine, St. Louis, Missouri 63110, USA;
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Harvey JRM, Plante AE, Meredith AL. Ion Channels Controlling Circadian Rhythms in Suprachiasmatic Nucleus Excitability. Physiol Rev 2020; 100:1415-1454. [PMID: 32163720 DOI: 10.1152/physrev.00027.2019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Animals synchronize to the environmental day-night cycle by means of an internal circadian clock in the brain. In mammals, this timekeeping mechanism is housed in the suprachiasmatic nucleus (SCN) of the hypothalamus and is entrained by light input from the retina. One output of the SCN is a neural code for circadian time, which arises from the collective activity of neurons within the SCN circuit and comprises two fundamental components: 1) periodic alterations in the spontaneous excitability of individual neurons that result in higher firing rates during the day and lower firing rates at night, and 2) synchronization of these cellular oscillations throughout the SCN. In this review, we summarize current evidence for the identity of ion channels in SCN neurons and the mechanisms by which they set the rhythmic parameters of the time code. During the day, voltage-dependent and independent Na+ and Ca2+ currents, as well as several K+ currents, contribute to increased membrane excitability and therefore higher firing frequency. At night, an increase in different K+ currents, including Ca2+-activated BK currents, contribute to membrane hyperpolarization and decreased firing. Layered on top of these intrinsically regulated changes in membrane excitability, more than a dozen neuromodulators influence action potential activity and rhythmicity in SCN neurons, facilitating both synchronization and plasticity of the neural code.
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Affiliation(s)
- Jenna R M Harvey
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland
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Liang L, Li X, Moutton S, Schrier Vergano SA, Cogné B, Saint-Martin A, Hurst ACE, Hu Y, Bodamer O, Thevenon J, Hung CY, Isidor B, Gerard B, Rega A, Nambot S, Lehalle D, Duffourd Y, Thauvin-Robinet C, Faivre L, Bézieau S, Dure LS, Helbling DC, Bick D, Xu C, Chen Q, Mancini GMS, Vitobello A, Wang QK. De novo loss-of-function KCNMA1 variants are associated with a new multiple malformation syndrome and a broad spectrum of developmental and neurological phenotypes. Hum Mol Genet 2020; 28:2937-2951. [PMID: 31152168 DOI: 10.1093/hmg/ddz117] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Revised: 04/17/2019] [Accepted: 05/21/2019] [Indexed: 02/06/2023] Open
Abstract
KCNMA1 encodes the large-conductance Ca2+- and voltage-activated K+ (BK) potassium channel α-subunit, and pathogenic gain-of-function variants in this gene have been associated with a dominant form of generalized epilepsy and paroxysmal dyskinesia. Here, we genetically and functionally characterize eight novel loss-of-function (LoF) variants of KCNMA1. Genome or exome sequencing and the participation in the international Matchmaker Exchange effort allowed for the identification of novel KCNMA1 variants. Patch clamping was used to assess functionality of mutant BK channels. The KCNMA1 variants p.(Ser351Tyr), p.(Gly356Arg), p.(Gly375Arg), p.(Asn449fs) and p.(Ile663Val) abolished the BK current, whereas p.(Cys413Tyr) and p.(Pro805Leu) reduced the BK current amplitude and shifted the activation curves toward positive potentials. The p.(Asp984Asn) variant reduced the current amplitude without affecting kinetics. A phenotypic analysis of the patients carrying the recurrent p.(Gly375Arg) de novo missense LoF variant revealed a novel syndromic neurodevelopmental disorder associated with severe developmental delay, visceral and cardiac malformations, connective tissue presentations with arterial involvement, bone dysplasia and characteristic dysmorphic features. Patients with other LoF variants presented with neurological and developmental symptoms including developmental delay, intellectual disability, ataxia, axial hypotonia, cerebral atrophy and speech delay/apraxia/dysarthria. Therefore, LoF KCNMA1 variants are associated with a new syndrome characterized by a broad spectrum of neurological phenotypes and developmental disorders. LoF variants of KCNMA1 cause a new syndrome distinctly different from gain-of-function variants in the same gene.
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Affiliation(s)
- Lina Liang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Xia Li
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Sébastien Moutton
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Samantha A Schrier Vergano
- Medical Genetics and Metabolism, Children's Hospital of The King's Daughters, Eastern Virginia Medical School, Norfolk, VA 23507, USA
| | - Benjamin Cogné
- Service de Génétique Médicale, CHU de Nantes, Nantes 44093, France
| | - Anne Saint-Martin
- Neuropédiatrie, Centre de Référence des Epilepsies Rares, Hôpitaux Universitaires de Strasbourg, Strasbourg 67098, France
| | - Anna C E Hurst
- Department of Genetics, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Yushuang Hu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Olaf Bodamer
- Division of Genetics and Genomics, Boston Children's Hospital/Harvard Medical School, Boston, MA 02115, USA.,The Broad Institute of Harvard and MIT, Boston, MA 02115, USA
| | - Julien Thevenon
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Christina Y Hung
- Division of Genetics and Genomics, Boston Children's Hospital/Harvard Medical School, Boston, MA 02115, USA
| | - Bertrand Isidor
- Service de Génétique Médicale, CHU de Nantes, Nantes 44093, France
| | - Bénédicte Gerard
- Institut de Génétique Médicale d'Alsace, Laboratoires de Diagnostic Génétique, Unité de Génétique Moléculaire, Nouvel Hôpital Civil, Strasbourg 67000, Franc
| | - Adelaide Rega
- Pediatric Radiologist, Département de Radiologie et Imagerie Diagnostique et Thérapeutique, CHU, Dijon 21079, France
| | - Sophie Nambot
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Daphné Lehalle
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Yannis Duffourd
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Christel Thauvin-Robinet
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Laurence Faivre
- Centre de Référence Anomalies du Développement et Syndromes Malformatifs, Hôpital d'Enfants, Dijon 21079, France.,Centre de Référence Déficiences Intellectuelles de Causes Rares, Hôpital d'Enfants, Dijon 21079, France.,Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Stéphane Bézieau
- Service de Génétique Médicale, CHU de Nantes, Nantes 44093, France
| | - Leon S Dure
- Department of Pediatrics and Neurology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Daniel C Helbling
- Clinical Services Laboratory, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - David Bick
- Clinical Services Laboratory, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Chengqi Xu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China
| | - Qiuyun Chen
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Department of Cardiovascular Medicine, Cleveland Clinic, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA
| | - Grazia M S Mancini
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam 3015, The Netherlands
| | - Antonio Vitobello
- Inserm UMR 1231 GAD team, Genetics of Developmental Disorders, Université de Bourgogne Franche-Comté, Dijon 21070, France
| | - Qing Kenneth Wang
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Center for Human Genome Research, Cardio-X Institute, Huazhong University of Science and Technology, Wuhan, Hubei 430074, P. R. China.,Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Department of Cardiovascular Medicine, Cleveland Clinic, Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA.,Department of Genetics and Genome Science, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
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49
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Plante AE, Lai MH, Lu J, Meredith AL. Effects of Single Nucleotide Polymorphisms in Human KCNMA1 on BK Current Properties. Front Mol Neurosci 2019; 12:285. [PMID: 31849601 PMCID: PMC6901604 DOI: 10.3389/fnmol.2019.00285] [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: 07/19/2019] [Accepted: 11/12/2019] [Indexed: 12/14/2022] Open
Abstract
BK Ca2+-activated K+ channels are important regulators of membrane excitability. Multiple regulatory mechanisms tailor BK current properties across tissues, such as alternative splicing, posttranslational modifications, and auxiliary subunits. Another potential mechanism for modulating BK channel activity is genetic variation due to single nucleotide polymorphisms (SNPs). The gene encoding the human BK α subunit, KCNMA1, contains hundreds of SNPs. However, the variation in BK channel activity due to SNPs is not well studied. Here, we screened the effects of four SNPs (A138V, C495G, N599D, and R800W) on BK currents in HEK293T cells, selected based on predicted protein pathogenicity or disease linkage. We found that the SNPs C495G and R800W had the largest effects on BK currents, affecting the conductance–voltage relationship across multiple Ca2+ conditions in the context of two BK channel splice variants. In symmetrical K+, C495G shifted the V1/2 to more hyperpolarized potentials (by −15 to −20 mV) and accelerated activation, indicating C495G confers some gain-of-function properties. R800W shifted the V1/2 to more depolarized potentials (+15 to +35 mV) and slowed activation, conferring loss-of-function properties. Moreover, the C495G and R800W effects on current properties were found to persist with posttranslational modifications. In contrast, A138V and N599D had smaller and more variable effects on current properties. Neither application of alkaline phosphatase to patches, which results in increased BK channel activity attributed to channel dephosphorylation, nor bidirectional redox modulations completely abrogated SNP effects on BK currents. Lastly, in physiological K+, C495G increased the amplitude of action potential (AP)-evoked BK currents, while R800W had a more limited effect. However, the introduction of R800W in parallel with the epilepsy-linked mutation D434G (D434G/R800W) decreased the amplitude of AP-evoked BK currents compared with D434G alone. These results suggest that in a physiological context, C495G could increase BK activation, while the effects of the loss-of-function SNP R800W could oppose the gain-of-function effects of an epilepsy-linked mutation. Together, these results implicate naturally occurring human genetic variation as a potential modifier of BK channel activity across a variety of conditions.
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Affiliation(s)
- Amber E Plante
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Michael H Lai
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Jessica Lu
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Andrea L Meredith
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, United States
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50
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Smith P, Buhl E, Tsaneva-Atanasova K, Hodge JJL. Shaw and Shal voltage-gated potassium channels mediate circadian changes in Drosophila clock neuron excitability. J Physiol 2019; 597:5707-5722. [PMID: 31612994 DOI: 10.1113/jp278826] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Accepted: 10/03/2019] [Indexed: 01/08/2023] Open
Abstract
As in mammals, Drosophila circadian clock neurons display rhythms of activity with higher action potential firing rates and more positive resting membrane potentials during the day. This rhythmic excitability has been widely observed but, critically, its regulation remains unresolved. We have characterized and modelled the changes underlying these electrical activity rhythms in the lateral ventral clock neurons (LNvs). We show that currents mediated by the voltage-gated potassium channels Shaw (Kv3) and Shal (Kv4) oscillate in a circadian manner. Disruption of these channels, by expression of dominant negative (DN) subunits, leads to changes in circadian locomotor activity and shortens lifespan. LNv whole-cell recordings then show that changes in Shaw and Shal currents drive changes in action potential firing rate and that these rhythms are abolished when the circadian molecular clock is stopped. A whole-cell biophysical model using Hodgkin-Huxley equations can recapitulate these changes in electrical activity. Based on this model and by using dynamic clamp to manipulate clock neurons directly, we can rescue the pharmacological block of Shaw and Shal, restore the firing rhythm, and thus demonstrate the critical importance of Shaw and Shal. Together, these findings point to a key role for Shaw and Shal in controlling circadian firing of clock neurons and show that changes in clock neuron currents can account for this. Moreover, with dynamic clamp we can switch the LNvs between morning-like and evening-like states of electrical activity. We conclude that changes in Shaw and Shal underlie the daily oscillation in LNv firing rate.
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Affiliation(s)
- Philip Smith
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Edgar Buhl
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Krasimira Tsaneva-Atanasova
- Department of Mathematics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK
| | - James J L Hodge
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, University Walk, Bristol, BS8 1TD, UK
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