1
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Xiong A, Richmond JE, Kim H. Presynaptic neurons self-tune by inversely coupling neurotransmitter release with the abundance of CaV2 voltage-gated Ca 2+ channels. Proc Natl Acad Sci U S A 2024; 121:e2404969121. [PMID: 39172783 PMCID: PMC11363341 DOI: 10.1073/pnas.2404969121] [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: 03/09/2024] [Accepted: 07/12/2024] [Indexed: 08/24/2024] Open
Abstract
The abundance of CaV2 voltage-gated calcium channels is linked to presynaptic homeostatic plasticity (PHP), a process that recalibrates synaptic strength to maintain the stability of neural circuits. However, the molecular and cellular mechanisms governing PHP and CaV2 channels are not completely understood. Here, we uncover a previously not described form of PHP in Caenorhabditis elegans, revealing an inverse regulatory relationship between the efficiency of neurotransmitter release and the abundance of UNC-2/CaV2 channels. Gain-of-function unc-2SL(S240L) mutants, which carry a mutation analogous to the one causing familial hemiplegic migraine type 1 in humans, showed markedly reduced channel abundance despite increased channel functionality. Reducing synaptic release in these unc-2SL(S240L) mutants restored channel levels to those observed in wild-type animals. Conversely, loss-of-function unc-2DA(D726A) mutants, which harbor the D726A mutation in the channel pore, exhibited a marked increase in channel abundance. Enhancing synaptic release in unc-2DA mutants reversed this increase in channel levels. Importantly, this homeostatic regulation of UNC-2 channel levels is accompanied by the structural remodeling of the active zone (AZ); specifically, unc-2DA mutants, which exhibit increased channel abundance, showed parallel increases in select AZ proteins. Finally, our forward genetic screen revealed that WWP-1, a HECT family E3 ubiquitin ligase, is a key homeostatic mediator that removes UNC-2 from synapses. These findings highlight a self-tuning PHP regulating UNC-2/CaV2 channel abundance along with AZ reorganization, ensuring synaptic strength and stability.
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Affiliation(s)
- Ame Xiong
- Discipline of Cell Biology & Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
| | - Janet E. Richmond
- Department of Biological Sciences, University of Illinois, Chicago, IL60607
| | - Hongkyun Kim
- Discipline of Cell Biology & Anatomy, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, IL60064
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2
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Martus D, Williams SK, Pichi K, Mannebach-Götz S, Kaiser N, Wardas B, Fecher-Trost C, Meyer MR, Schmitz F, Beck A, Fairless R, Diem R, Flockerzi V, Belkacemi A. Cavβ3 Contributes to the Maintenance of the Blood-Brain Barrier and Alleviates Symptoms of Experimental Autoimmune Encephalomyelitis. Arterioscler Thromb Vasc Biol 2024; 44:1833-1851. [PMID: 38957986 DOI: 10.1161/atvbaha.124.321141] [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: 04/23/2024] [Accepted: 06/21/2024] [Indexed: 07/04/2024]
Abstract
BACKGROUND Tight control of cytoplasmic Ca2+ concentration in endothelial cells is essential for the regulation of endothelial barrier function. Here, we investigated the role of Cavβ3, a subunit of voltage-gated Ca2+ (Cav) channels, in modulating Ca2+ signaling in brain microvascular endothelial cells (BMECs) and how this contributes to the integrity of the blood-brain barrier. METHODS We investigated the function of Cavβ3 in BMECs by Ca2+ imaging and Western blot, examined the endothelial barrier function in vitro and the integrity of the blood-brain barrier in vivo, and evaluated disease course after induction of experimental autoimmune encephalomyelitis in mice using Cavβ3-/- (Cavβ3-deficient) mice as controls. RESULTS We identified Cavβ3 protein in BMECs, but electrophysiological recordings did not reveal significant Cav channel activity. In vivo, blood-brain barrier integrity was reduced in the absence of Cavβ3. After induction of experimental autoimmune encephalomyelitis, Cavβ3-/- mice showed earlier disease onset with exacerbated clinical disability and increased T-cell infiltration. In vitro, the transendothelial resistance of Cavβ3-/- BMEC monolayers was lower than that of wild-type BMEC monolayers, and the organization of the junctional protein ZO-1 (zona occludens-1) was impaired. Thrombin stimulates inositol 1,4,5-trisphosphate-dependent Ca2+ release, which facilitates cell contraction and enhances endothelial barrier permeability via Ca2+-dependent phosphorylation of MLC (myosin light chain). These effects were more pronounced in Cavβ3-/- than in wild-type BMECs, whereas the differences were abolished in the presence of the MLCK (MLC kinase) inhibitor ML-7. Expression of Cacnb3 cDNA in Cavβ3-/- BMECs restored the wild-type phenotype. Coimmunoprecipitation and mass spectrometry demonstrated the association of Cavβ3 with inositol 1,4,5-trisphosphate receptor proteins. CONCLUSIONS Independent of its function as a subunit of Cav channels, Cavβ3 interacts with the inositol 1,4,5-trisphosphate receptor and is involved in the tight control of cytoplasmic Ca2+ concentration and Ca2+-dependent MLC phosphorylation in BMECs, and this role of Cavβ3 in BMECs contributes to blood-brain barrier integrity and attenuates the severity of experimental autoimmune encephalomyelitis disease.
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MESH Headings
- Animals
- Female
- Male
- Mice
- Blood-Brain Barrier/metabolism
- Calcium/metabolism
- Calcium Channels/metabolism
- Calcium Channels/genetics
- Calcium Signaling
- Capillary Permeability
- Cells, Cultured
- Encephalomyelitis, Autoimmune, Experimental/metabolism
- Encephalomyelitis, Autoimmune, Experimental/genetics
- Endothelial Cells/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Inositol 1,4,5-Trisphosphate Receptors/genetics
- Mice, Inbred C57BL
- Mice, Knockout
- Myosin Light Chains/metabolism
- Myosin-Light-Chain Kinase/metabolism
- Myosin-Light-Chain Kinase/genetics
- Phosphorylation
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Affiliation(s)
- Damian Martus
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Sarah K Williams
- Neurologische Klinik, Universitätsklinikum Heidelberg, Germany (S.K.W., K.P., R.F., R.D.)
- Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany (R.F., S.K.W.)
| | - Kira Pichi
- Neurologische Klinik, Universitätsklinikum Heidelberg, Germany (S.K.W., K.P., R.F., R.D.)
| | - Stefanie Mannebach-Götz
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Nicolas Kaiser
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Barbara Wardas
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Claudia Fecher-Trost
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Markus R Meyer
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Frank Schmitz
- Institut für Anatomie und Zellbiologie (F.S.), Universität des Saarlandes, Homburg, Germany
| | - Andreas Beck
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Richard Fairless
- Neurologische Klinik, Universitätsklinikum Heidelberg, Germany (S.K.W., K.P., R.F., R.D.)
- Clinical Cooperation Unit Neurooncology, German Cancer Consortium (DKTK), German Cancer Research Center (DKFZ), Heidelberg, Germany (R.F., S.K.W.)
| | - Ricarda Diem
- Neurologische Klinik, Universitätsklinikum Heidelberg, Germany (S.K.W., K.P., R.F., R.D.)
| | - Veit Flockerzi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
| | - Anouar Belkacemi
- Experimentelle und Klinische Pharmakologie und Toxikologie, Präklinisches Zentrum für Molekulare Signalverarbeitung, PharmaScienceHub (D.M., S.M.-G., N.K., B.W., C.F.-T., M.R.M., A. Beck, V.F., A. Belkacemi), Universität des Saarlandes, Homburg, Germany
- Now with Pharmakologisches Institut, Ruprecht-Karls-Universität Heidelberg, Germany (A. Belkacemi)
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3
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Chin M, Kaeser PS. The intracellular C-terminus confers compartment-specific targeting of voltage-gated calcium channels. Cell Rep 2024; 43:114428. [PMID: 38996073 DOI: 10.1016/j.celrep.2024.114428] [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: 12/28/2023] [Revised: 06/07/2024] [Accepted: 06/18/2024] [Indexed: 07/14/2024] Open
Abstract
To achieve the functional polarization that underlies brain computation, neurons sort protein material into distinct compartments. Ion channel composition, for example, differs between axons and dendrites, but the molecular determinants for their polarized trafficking remain obscure. Here, we identify mechanisms that target voltage-gated Ca2+ channels (CaVs) to distinct subcellular compartments. In hippocampal neurons, CaV2s trigger neurotransmitter release at the presynaptic active zone, and CaV1s localize somatodendritically. After knockout of all three CaV2s, expression of CaV2.1, but not CaV1.3, restores neurotransmitter release. We find that chimeric CaV1.3s with CaV2.1 intracellular C-termini localize to the active zone, mediate synaptic vesicle exocytosis, and render release sensitive to CaV1 blockers. This dominant targeting function of the CaV2.1 C-terminus requires the first EF hand in its proximal segment, and replacement of the CaV2.1 C-terminus with that of CaV1.3 abolishes CaV2.1 active zone localization and function. We conclude that CaV intracellular C-termini mediate compartment-specific targeting.
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Affiliation(s)
- Morven Chin
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Pascal S Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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4
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Dong P, Bakhurin K, Li Y, Mikati MA, Cui J, Grill WM, Yin HH, Yang H. Attenuating midline thalamus bursting to mitigate absence epilepsy. Proc Natl Acad Sci U S A 2024; 121:e2403763121. [PMID: 38968111 PMCID: PMC11252967 DOI: 10.1073/pnas.2403763121] [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: 02/29/2024] [Accepted: 05/31/2024] [Indexed: 07/07/2024] Open
Abstract
Advancing the mechanistic understanding of absence epilepsy is crucial for developing new therapeutics, especially for patients unresponsive to current treatments. Utilizing a recently developed mouse model of absence epilepsy carrying the BK gain-of-function channelopathy D434G, here we report that attenuating the burst firing of midline thalamus (MLT) neurons effectively prevents absence seizures. We found that enhanced BK channel activity in the BK-D434G MLT neurons promotes synchronized bursting during the ictal phase of absence seizures. Modulating MLT neurons through pharmacological reagents, optogenetic stimulation, or deep brain stimulation effectively attenuates burst firing, leading to reduced absence seizure frequency and increased vigilance. Additionally, enhancing vigilance by amphetamine, a stimulant medication, or physical perturbation also effectively suppresses MLT bursting and prevents absence seizures. These findings suggest that the MLT is a promising target for clinical interventions. Our diverse approaches offer valuable insights for developing next generation therapeutics to treat absence epilepsy.
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Affiliation(s)
- Ping Dong
- Department of Biochemistry, Duke University Medical Center, Durham, NC27710
| | | | - Yuhui Li
- Department of Biomedical Engineering, Duke University, Durham, NC27708
| | - Mohamad A. Mikati
- Department of Neurobiology, Duke University Medical Center, Durham, NC27710
- Department of Pediatrics, Duke University Medical Center, Durham, NC27710
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, MO63130
| | - Warren M. Grill
- Department of Biomedical Engineering, Duke University, Durham, NC27708
- Department of Neurobiology, Duke University Medical Center, Durham, NC27710
- Department of Neurosurgery, Duke University Medical Center, Durham, NC27710
| | - Henry H. Yin
- Department of Psychology and Neuroscience, Duke University, Durham, NC27708
- Department of Neurobiology, Duke University Medical Center, Durham, NC27710
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC27710
- Department of Neurobiology, Duke University Medical Center, Durham, NC27710
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5
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Ni Z, Wang J, Yu X, Wang Y, Wang J, He X, Li C, Deng G, Shi J, Kong H, Jiang Y, Chen P, Zeng X, Tian G, Chen H, Bu Z. Influenza virus uses mGluR2 as an endocytic receptor to enter cells. Nat Microbiol 2024; 9:1764-1777. [PMID: 38849624 PMCID: PMC11222159 DOI: 10.1038/s41564-024-01713-x] [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: 11/14/2023] [Accepted: 04/24/2024] [Indexed: 06/09/2024]
Abstract
Influenza virus infection is initiated by the attachment of the viral haemagglutinin (HA) protein to sialic acid receptors on the host cell surface. Most virus particles enter cells through clathrin-mediated endocytosis (CME). However, it is unclear how viral binding signals are transmitted through the plasma membrane triggering CME. Here we found that metabotropic glutamate receptor subtype 2 (mGluR2) and potassium calcium-activated channel subfamily M alpha 1 (KCa1.1) are involved in the initiation and completion of CME of influenza virus using an siRNA screen approach. Influenza virus HA directly interacted with mGluR2 and used it as an endocytic receptor to initiate CME. mGluR2 interacted and activated KCa1.1, leading to polymerization of F-actin, maturation of clathrin-coated pits and completion of the CME of influenza virus. Importantly, mGluR2-knockout mice were significantly more resistant to different influenza subtypes than the wild type. Therefore, blocking HA and mGluR2 interaction could be a promising host-directed antiviral strategy.
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Affiliation(s)
- Zixin Ni
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Jinliang Wang
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xiaofei Yu
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Yifan Wang
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Jingfei Wang
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xijun He
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Chengjun Li
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Guohua Deng
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Jianzhong Shi
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Huihui Kong
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Yongping Jiang
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Pucheng Chen
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Xianying Zeng
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Guobin Tian
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China
| | - Hualan Chen
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
| | - Zhigao Bu
- State Key Laboratory for Animal Disease Control, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin, People's Republic of China.
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6
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Sun X, Yazejian B, Peskoff A, Grinnell AD. Experimentally monitored calcium dynamics at synaptic active zones during neurotransmitter release in neuron-muscle cell cultures. Eur J Neurosci 2024; 59:2293-2319. [PMID: 38483240 DOI: 10.1111/ejn.16289] [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: 08/30/2023] [Revised: 01/04/2024] [Accepted: 02/01/2024] [Indexed: 05/08/2024]
Abstract
Ca2+-dependent K+ (BK) channels at varicosities in Xenopus nerve-muscle cell cultures were used to quantify experimentally the instantaneous active zone [Ca2+]AZ resulting from different rates and durations of Ca2+ entry in the absence of extrinsic buffers and correlate this with neurotransmitter release. Ca2+ tail currents produce mean peak [Ca2+]AZ ~ 30 μM; with continued influx, [Ca2+]AZ reaches ~45-60 μM at different rates depending on Ca2+ driving force and duration of influx. Both IBK and release are dependent on Ca2+ microdomains composed of both N- and L-type Ca channels. Domains collapse with a time constant of ~0.6 ms. We have constructed an active zone (AZ) model that approximately fits this data, and depends on incorporation of the high-capacity, low-affinity fixed buffer represented by phospholipid charges in the plasma membrane. Our observations suggest that in this preparation, (1) some BK channels, but few if any of the Ca2+ sensors that trigger release, are located within Ca2+ nanodomains while a large fraction of both are located far enough from Ca channels to be blockable by EGTA, (2) the IBK is more sensitive than the excitatory postsynaptic current (EPSC) to [Ca2+]AZ (K1/2-26 μM vs. ~36 μM [Ca2+]AZ); (3) with increasing [Ca2+]AZ, the IBK grows with a Hill coefficient of 2.5, the EPSC with a coefficient of 3.9; (4) release is dependent on the highest [Ca2+] achieved, independent of the time to reach it; (5) the varicosity synapses differ from mature frog nmjs in significant ways; and (6) BK channels are useful reporters of local [Ca2+]AZ.
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Affiliation(s)
- Xiaoping Sun
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Bruce Yazejian
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Arthur Peskoff
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
| | - Alan D Grinnell
- Department of Physiology, David Geffen School of Medicine, UCLA, Los Angeles, CA, USA
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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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Delgado-Bermúdez A, Yeste M, Bonet S, Pinart E. Physiological role of potassium channels in mammalian germ cell differentiation, maturation, and capacitation. Andrology 2024. [PMID: 38436215 DOI: 10.1111/andr.13606] [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: 10/30/2023] [Revised: 01/16/2024] [Accepted: 01/29/2024] [Indexed: 03/05/2024]
Abstract
BACKGROUND Ion channels are essential for differentiation and maturation of germ cells, and even for fertilization in mammals. Different types of potassium channels have been identified, which are grouped into voltage-gated channels (Kv), ligand-gated channels (Kligand ), inwardly rectifying channels (Kir ), and tandem pore domain channels (K2P ). MATERIAL-METHODS The present review includes recent findings on the role of potassium channels in sperm physiology of mammals. RESULTS-DISCUSSION While most studies conducted thus far have been focused on the physiological role of voltage- (Kv1, Kv3, and Kv7) and calcium-gated channels (SLO1 and SLO3) during sperm capacitation, especially in humans and rodents, little data about the types of potassium channels present in the plasma membrane of differentiating germ cells exist. In spite of this, recent evidence suggests that the content and regulation mechanisms of these channels vary throughout spermatogenesis. Potassium channels are also essential for the regulation of sperm cell volume during epididymal maturation and for preventing premature membrane hyperpolarization. It is important to highlight that the nature, biochemical properties, localization, and regulation mechanisms of potassium channels are species-specific. In effect, while SLO3 is the main potassium channel involved in the K+ current during sperm capacitation in rodents, different potassium channels are implicated in the K+ outflow and, thus, plasma membrane hyperpolarization during sperm capacitation in other mammalian species, such as humans and pigs. CONCLUSIONS Potassium conductance is essential for male fertility, not only during sperm capacitation but throughout the spermiogenesis and epididymal maturation.
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Affiliation(s)
- Ariadna Delgado-Bermúdez
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, Girona, Spain
- Department of Biology, Faculty of Sciences, Unit of Cell Biology, University of Girona, Girona, Spain
| | - Marc Yeste
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, Girona, Spain
- Department of Biology, Faculty of Sciences, Unit of Cell Biology, University of Girona, Girona, Spain
- Catalan Institution for Research and Advanced Studies (ICREA), Barcelona, Spain
| | - Sergi Bonet
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, Girona, Spain
- Department of Biology, Faculty of Sciences, Unit of Cell Biology, University of Girona, Girona, Spain
| | - Elisabeth Pinart
- Biotechnology of Animal and Human Reproduction (TechnoSperm), Institute of Food and Agricultural Technology, University of Girona, Girona, Spain
- Department of Biology, Faculty of Sciences, Unit of Cell Biology, University of Girona, Girona, Spain
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9
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Blömer LA, Giacalone E, Abbas F, Filipis L, Tegolo D, Migliore M, Canepari M. Kinetics and functional consequences of BK channels activation by N-type Ca 2+ channels in the dendrite of mouse neocortical layer-5 pyramidal neurons. Front Cell Neurosci 2024; 18:1353895. [PMID: 38419657 PMCID: PMC10899506 DOI: 10.3389/fncel.2024.1353895] [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: 12/11/2023] [Accepted: 01/24/2024] [Indexed: 03/02/2024] Open
Abstract
The back-propagation of an action potential (AP) from the axon/soma to the dendrites plays a central role in dendritic integration. This process involves an intricate orchestration of various ion channels, but a comprehensive understanding of the contribution of each channel type remains elusive. In this study, we leverage ultrafast membrane potential recordings (Vm) and Ca2+ imaging techniques to shed light on the involvement of N-type voltage-gated Ca2+ channels (VGCCs) in layer-5 neocortical pyramidal neurons' apical dendrites. We found a selective interaction between N-type VGCCs and large-conductance Ca2+-activated K+ channels (BK CAKCs). Remarkably, we observe that BK CAKCs are activated within a mere 500 μs after the AP peak, preceding the peak of the Ca2+ current triggered by the AP. Consequently, when N-type VGCCs are inhibited, the early broadening of the AP shape amplifies the activity of other VGCCs, leading to an augmented total Ca2+ influx. A NEURON model, constructed to replicate and support these experimental results, reveals the critical coupling between N-type and BK channels. This study not only redefines the conventional role of N-type VGCCs as primarily involved in presynaptic neurotransmitter release but also establishes their distinct and essential function as activators of BK CAKCs in neuronal dendrites. Furthermore, our results provide original functional validation of a physical interaction between Ca2+ and K+ channels, elucidated through ultrafast kinetic reconstruction. This insight enhances our understanding of the intricate mechanisms governing neuronal signaling and may have far-reaching implications in the field.
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Affiliation(s)
- Laila Ananda Blömer
- LIPhy, CNRS, Université Grenoble Alpes, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
| | - Elisabetta Giacalone
- Institute of Biophysics, National Research Council, Palermo, Italy
- Dipartimento Matematica e Informatica, Universitá degli Studi di Palermo, Palermo, Italy
| | - Fatima Abbas
- LIPhy, CNRS, Université Grenoble Alpes, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
| | - Luiza Filipis
- LIPhy, CNRS, Université Grenoble Alpes, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
| | - Domenico Tegolo
- Dipartimento Matematica e Informatica, Universitá degli Studi di Palermo, Palermo, Italy
| | - Michele Migliore
- Institute of Biophysics, National Research Council, Palermo, Italy
| | - Marco Canepari
- LIPhy, CNRS, Université Grenoble Alpes, Grenoble, France
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Valbonne, France
- Institut National de la Santé et Recherche Médicale, Paris, France
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10
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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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11
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Chen YC, Shih CL, Wu CL, Fang YH, So EC, Wu SN. Exploring the Impact of BK Ca Channel Function in Cellular Membranes on Cardiac Electrical Activity. Int J Mol Sci 2024; 25:1537. [PMID: 38338830 PMCID: PMC10855144 DOI: 10.3390/ijms25031537] [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: 12/13/2023] [Revised: 01/14/2024] [Accepted: 01/19/2024] [Indexed: 02/12/2024] Open
Abstract
This review paper delves into the current body of evidence, offering a thorough analysis of the impact of large-conductance Ca2+-activated K+ (BKCa or BK) channels on the electrical dynamics of the heart. Alterations in the activity of BKCa channels, responsible for the generation of the overall magnitude of Ca2+-activated K+ current at the whole-cell level, occur through allosteric mechanisms. The collaborative interplay between membrane depolarization and heightened intracellular Ca2+ ion concentrations collectively contribute to the activation of BKCa channels. Although fully developed mammalian cardiac cells do not exhibit functional expression of these ion channels, evidence suggests their presence in cardiac fibroblasts that surround and potentially establish close connections with neighboring cardiac cells. When cardiac cells form close associations with fibroblasts, the high single-ion conductance of these channels, approximately ranging from 150 to 250 pS, can result in the random depolarization of the adjacent cardiac cell membranes. While cardiac fibroblasts are typically electrically non-excitable, their prevalence within heart tissue increases, particularly in the context of aging myocardial infarction or atrial fibrillation. This augmented presence of BKCa channels' conductance holds the potential to amplify the excitability of cardiac cell membranes through effective electrical coupling between fibroblasts and cardiomyocytes. In this scenario, this heightened excitability may contribute to the onset of cardiac arrhythmias. Moreover, it is worth noting that the substances influencing the activity of these BKCa channels might influence cardiac electrical activity as well. Taken together, the BKCa channel activity residing in cardiac fibroblasts may contribute to cardiac electrical function occurring in vivo.
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Affiliation(s)
- Yin-Chia Chen
- Division of Cardiovascular Surgery, Department of Surgery, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Chia-Lung Shih
- Clinical Research Center, Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60056, Taiwan
| | - Chao-Liang Wu
- Ditmanson Medical Foundation Chia-Yi Christian Hospital, Chiayi City 60002, Taiwan
| | - Yi-Hsien Fang
- Institute of Clinical Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan 70403, Taiwan
| | - Edmund Cheung So
- Department of Anesthesia, An Nan Hospital, China Medical University, Tainan 70965, Taiwan
| | - Sheng-Nan Wu
- Department of Research and Education, An Nan Hospital, China Medical University, Tainan 70965, Taiwan
- School of Medicine, College of Medicine, National Sun Yat-sen University, Kaohsiung 80421, Taiwan
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12
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Chin M, Kaeser PS. The intracellular C-terminus confers compartment-specific targeting of voltage-gated Ca 2+ channels. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.23.573183. [PMID: 38187530 PMCID: PMC10769351 DOI: 10.1101/2023.12.23.573183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
To achieve the functional polarization that underlies brain computation, neurons sort protein material into distinct compartments. Ion channel composition, for example, differs between axons and dendrites, but the molecular determinants for their polarized trafficking remain obscure. Here, we identify the mechanisms that target voltage-gated Ca2+ channels (CaVs) to distinct subcellular compartments. In hippocampal neurons, CaV2s trigger neurotransmitter release at the presynaptic active zone, and CaV1s localize somatodendritically. After knockout of all three CaV2s, expression of CaV2.1, but not of CaV1.3, restores neurotransmitter release. Chimeric CaV1.3 channels with CaV2.1 intracellular C-termini localize to the active zone, mediate synaptic vesicle exocytosis, and render release fully sensitive to blockade of CaV1 channels. This dominant targeting function of the CaV2.1 C-terminus requires an EF hand in its proximal segment, and replacement of the CaV2.1 C-terminus with that of CaV1.3 abolishes CaV2.1 active zone localization. We conclude that the intracellular C-termini mediate compartment-specific CaV targeting.
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Affiliation(s)
- Morven Chin
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Pascal S. Kaeser
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
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13
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Jędrzejewska-Szmek J, Dorman DB, Blackwell KT. Making time and space for calcium control of neuron activity. Curr Opin Neurobiol 2023; 83:102804. [PMID: 37913687 PMCID: PMC10842147 DOI: 10.1016/j.conb.2023.102804] [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: 02/02/2023] [Revised: 10/02/2023] [Accepted: 10/03/2023] [Indexed: 11/03/2023]
Abstract
Calcium directly controls or indirectly regulates numerous functions that are critical for neuronal network activity. Intracellular calcium concentration is tightly regulated by numerous molecular mechanisms because spatial domains and temporal dynamics (not just peak amplitude) are critical for calcium control of synaptic plasticity and ion channel activation, which in turn determine neuron spiking activity. The computational models investigating calcium control are valuable because experiments achieving high spatial and temporal resolution simultaneously are technically unfeasible. Simulations of calcium nanodomains reveal that specific calcium sources can couple to specific calcium targets, providing a mechanism to determine the direction of synaptic plasticity. Cooperativity of calcium domains opposes specificity, suggesting that the dendritic branch might be the preferred computational unit of the neuron.
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Affiliation(s)
- Joanna Jędrzejewska-Szmek
- Laboratory of Neuroinformatics, Nencki Institute of Experimental Biology of Polish Academy of Science, 3 Pasteur Street, Warsaw, 02-093, Poland.
| | - Daniel B Dorman
- Department of Biomedical Engineering, Johns Hopkins University, 3400 N. Charles St., Baltimore, 21218, MD, USA
| | - Kim T Blackwell
- Bioengineering Department and Interdisciplinary Program in Neuroscience, George Mason University, 4400 University Drive, Fairfax, 22031, VA, USA
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14
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Pham T, Hussein T, Calis D, Bischof H, Skrabak D, Cruz Santos M, Maier S, Spähn D, Kalina D, Simonsig S, Ehinger R, Groschup B, Knipper M, Plesnila N, Ruth P, Lukowski R, Matt L. BK channels sustain neuronal Ca 2+ oscillations to support hippocampal long-term potentiation and memory formation. Cell Mol Life Sci 2023; 80:369. [PMID: 37989805 PMCID: PMC10663188 DOI: 10.1007/s00018-023-05016-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] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/25/2023] [Accepted: 10/24/2023] [Indexed: 11/23/2023]
Abstract
Mutations of large conductance Ca2+- and voltage-activated K+ channels (BK) are associated with cognitive impairment. Here we report that CA1 pyramidal neuron-specific conditional BK knock-out (cKO) mice display normal locomotor and anxiety behavior. They do, however, exhibit impaired memory acquisition and retrieval in the Morris Water Maze (MWM) when compared to littermate controls (CTRL). In line with cognitive impairment in vivo, electrical and chemical long-term potentiation (LTP) in cKO brain slices were impaired in vitro. We further used a genetically encoded fluorescent K+ biosensor and a Ca2+-sensitive probe to observe cultured hippocampal neurons during chemical LTP (cLTP) induction. cLTP massively reduced intracellular K+ concentration ([K+]i) while elevating L-Type Ca2+ channel- and NMDA receptor-dependent Ca2+ oscillation frequencies. Both, [K+]i decrease and Ca2+ oscillation frequency increase were absent after pharmacological BK inhibition or in cells lacking BK. Our data suggest that L-Type- and NMDAR-dependent BK-mediated K+ outflow significantly contributes to hippocampal LTP, as well as learning and memory.
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Affiliation(s)
- Thomas Pham
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Tamara Hussein
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Dila Calis
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Helmut Bischof
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - David Skrabak
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Melanie Cruz Santos
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Selina Maier
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - David Spähn
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Daniel Kalina
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Stefanie Simonsig
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Rebekka Ehinger
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Bernhard Groschup
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
| | - Marlies Knipper
- Department of Otolaryngology, Head and Neck Surgery, Molecular Physiology of Hearing, Tübingen Hearing Research Centre, University of Tübingen, Tübingen, Germany
| | - Nikolaus Plesnila
- Laboratory of Experimental Stroke Research, Institute for Stroke and Dementia Research (ISD), University Hospital, Ludwig-Maximilians-University Munich (LMU), Munich, Germany
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Lucas Matt
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, Tübingen, Germany.
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15
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Mochida S. Calcium Channels and Calcium-Binding Proteins. Int J Mol Sci 2023; 24:14257. [PMID: 37762560 PMCID: PMC10532058 DOI: 10.3390/ijms241814257] [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: 06/29/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Signals of nerve impulses are transmitted to excitatory cells to induce the action of organs via the activation of Ca2+ entry through voltage-gated Ca2+ channels (VGCC), which are classified based on their activation threshold into high- and low-voltage activated channels, expressed specifically for each organ [...].
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Affiliation(s)
- Sumiko Mochida
- Department of Physiology, Tokyo Medical University, Tokyo 160-8402, Japan
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16
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Michelucci A, Sforna L, Di Battista A, Franciolini F, Catacuzzeno L. Ca 2+ -activated K + channels regulate cell volume in human glioblastoma cells. J Cell Physiol 2023; 238:2120-2134. [PMID: 37431808 DOI: 10.1002/jcp.31072] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 06/10/2023] [Accepted: 06/20/2023] [Indexed: 07/12/2023]
Abstract
Glioblastoma (GBM), the most lethal form of brain tumors, bases its malignancy on the strong ability of its cells to migrate and invade the narrow spaces of healthy brain parenchyma. Cell migration and invasion are both critically dependent on changes in cell volume and shape driven by the transmembrane transport of osmotically important ions such as K+ and Cl- . However, while the Cl- channels participating in cell volume regulation have been clearly identified, the precise nature of the K+ channels involved is still uncertain. Using a combination of electrophysiological and imaging approaches in GBM U87-MG cells, we found that hypotonic-induced cell swelling triggered the opening of Ca2+ -activated K+ (KCa ) channels of large and intermediate conductance (BKCa and IKCa , respectively), both highly expressed in GBM cells. The influx of Ca2+ mediated by the hypotonic-induced activation of mechanosensitive channels was found to be a key step for opening both the BKCa and the IKCa channels. Finally, the activation of both KCa channels mediated by mechanosensitive channels was found to be essential for the development of the regulatory volume decrease following hypotonic shock. Taken together, these data indicate that KCa channels are the main K+ channels responsible for the volume regulation in U87-MG cells.
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Affiliation(s)
- Antonio Michelucci
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Luigi Sforna
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Angela Di Battista
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology, and Biotechnology, University of Perugia, Perugia, Italy
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17
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Chen AL, Wu TH, Shi L, Clusin WT, Kao PN. Calcium-Activated Big-Conductance (BK) Potassium Channels Traffic through Nuclear Envelopes into Kinocilia in Ray Electrosensory Cells. Cells 2023; 12:2125. [PMID: 37681857 PMCID: PMC10486799 DOI: 10.3390/cells12172125] [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: 07/20/2023] [Revised: 08/15/2023] [Accepted: 08/19/2023] [Indexed: 09/09/2023] Open
Abstract
Electroreception through ampullae of Lorenzini in the little skate, Leucoraja erinacea, involves functional coupling between voltage-activated calcium channels (CaV1.3, cacna1d) and calcium-activated big-conductance potassium (BK) channels (BK, kcnma1). Whole-mount confocal microscopy was used to characterize the pleiotropic expression of BK and CaV1.3 in intact ampullae. BK and CaV1.3 are co-expressed in electrosensory cell plasma membranes, nuclear envelopes and kinocilia. Nuclear localization sequences (NLS) were predicted in BK and CaV1.3 by bioinformatic sequence analyses. The BK NLS is bipartite, occurs at an alternative splice site for the mammalian STREX exon and contains sequence targets for post-translational phosphorylation. Nuclear localization of skate BK channels was characterized in heterologously transfected HEK293 cells. Double-point mutations in the bipartite NLS (KR to AA or SVLS to AVLA) independently attenuated BK channel nuclear localization. These findings support the concept that BK partitioning between the electrosensory cell plasma membrane, nucleus and kinocilium may be regulated through a newly identified bipartite NLS.
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Affiliation(s)
- Abby L. Chen
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; (A.L.C.); (T.-H.W.); (L.S.)
| | - Ting-Hsuan Wu
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; (A.L.C.); (T.-H.W.); (L.S.)
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lingfang Shi
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; (A.L.C.); (T.-H.W.); (L.S.)
| | - William T. Clusin
- Department of Medicine, Division of Cardiovascular Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA;
| | - Peter N. Kao
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA; (A.L.C.); (T.-H.W.); (L.S.)
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18
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Hua J, Garcia de Paco E, Linck N, Maurice T, Desrumaux C, Manoury B, Rassendren F, Ulmann L. Microglial P2X4 receptors promote ApoE degradation and contribute to memory deficits in Alzheimer's disease. Cell Mol Life Sci 2023; 80:138. [PMID: 37145189 PMCID: PMC10163120 DOI: 10.1007/s00018-023-04784-x] [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: 01/18/2023] [Revised: 04/18/2023] [Accepted: 04/19/2023] [Indexed: 05/06/2023]
Abstract
Numerous evidences support that microglia contributes to the progression of Alzheimer's disease. P2X4 receptors are ATP-gated channels with high calcium permeability, which are de novo expressed in a subset of reactive microglia associated with various pathological contexts, contributing to microglial functions. P2X4 receptors are mainly localized in lysosomes and trafficking to the plasma membrane is tightly regulated. Here, we investigated the role of P2X4 in the context of Alzheimer's disease (AD). Using proteomics, we identified Apolipoprotein E (ApoE) as a specific P2X4 interacting protein. We found that P2X4 regulates lysosomal cathepsin B (CatB) activity promoting ApoE degradation; P2rX4 deletion results in higher amounts of intracellular and secreted ApoE in both bone-marrow-derived macrophage (BMDM) and microglia from APPswe/PSEN1dE9 brain. In both human AD brain and APP/PS1 mice, P2X4 and ApoE are almost exclusively expressed in plaque-associated microglia. In 12-month-old APP/PS1 mice, genetic deletion of P2rX4 reverses topographical and spatial memory impairment and reduces amount of soluble small aggregates of Aß1-42 peptide, while no obvious alteration of plaque-associated microglia characteristics is observed. Our results support that microglial P2X4 promotes lysosomal ApoE degradation, indirectly altering Aß peptide clearance, which in turn might promotes synaptic dysfunctions and cognitive deficits. Our findings uncover a specific interplay between purinergic signaling, microglial ApoE, soluble Aß (sAß) species and cognitive deficits associated with AD.
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Affiliation(s)
- Jennifer Hua
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Elvira Garcia de Paco
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Nathalie Linck
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Tangui Maurice
- MMDN, Univ Montpellier, EPHE, INSERM, Montpellier, France
| | | | - Bénédicte Manoury
- Institut Necker Enfants Malades, INSERM, CNRS, Université de Paris, Paris, France
| | - François Rassendren
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France
- LabEx Ion Channel Science and Therapeutics, Montpellier, France
| | - Lauriane Ulmann
- IGF, Univ Montpellier, CNRS, INSERM, Montpellier, France.
- LabEx Ion Channel Science and Therapeutics, Montpellier, France.
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19
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Soloviev A, Ivanova I, Sydorenko V, Sukhanova K, Melnyk M, Dryn D, Zholos A. Calcium-dependent modulation of BK Ca channel activity induced by plasmonic gold nanoparticles in pulmonary artery smooth muscle cells and hippocampal neurons. Acta Physiol (Oxf) 2023; 237:e13922. [PMID: 36599422 DOI: 10.1111/apha.13922] [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: 03/25/2022] [Revised: 12/07/2022] [Accepted: 01/02/2023] [Indexed: 01/06/2023]
Abstract
AIM Gold nanoparticles are widely used for biomedical applications, but the precise molecular mechanism of their interaction with cellular structures is still unclear. Assuming that intracellular calcium fluctuations associated with surface plasmon-induced calcium entry could modulate the activity of potassium channels, we studied the effect of 5 nm gold nanoparticles on calcium-dependent potassium channels and associated calcium signaling in freshly isolated rat pulmonary artery smooth muscle cells and cultured hippocampal neurons. METHODS Outward potassium currents were recorded using patch-clamp techniques. Changes in intracellular calcium concentration were measured using the high affinity Ca2+ fluorescent indicator fluo-3 and laser confocal microscope. RESULTS In pulmonary artery smooth muscle cells, plasmonic gold nanoparticles increased the amplitude of currents via large-conductance Ca2+ -activated potassium channels, which was potentiated by green laser irradiation near plasmon resonance wavelength (532 nm). Buffering of intracellular free calcium with ethylene glycol-bis-N,N,N',N'-tetraacetic acid (EGTA) abolished these effects. Furthermore, using confocal laser microscopy it was found that application of gold nanoparticles caused oscillations of intracellular calcium concentration that were decreasing in amplitude with time. In cultured hippocampal neurons gold nanoparticles inhibited the effect of EGTA slowing down the decline of the BKCa current while partially restoring the amplitude of the slow after hyperpolarizing currents. CONCLUSION We conclude that fluctuations in intracellular calcium can modulate plasmonic gold nanoparticles-induced gating of BKCa channels in smooth muscle cells and neurons through an indirect mechanism, probably involving the interaction of plasmon resonance with calcium-permeable ion channels, which leads to a change in intracellular calcium level.
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Affiliation(s)
- Anatoly Soloviev
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Irina Ivanova
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Vadym Sydorenko
- Department of Pharmacology of Cell Signaling Systems and Experimental Therapeutics, Institute of Pharmacology and Toxicology, National Academy of Medical Science of Ukraine, Kyiv, Ukraine
| | - Khrystyna Sukhanova
- McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Mariia Melnyk
- Department of Biophysics and Medical Informatics, Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
- Department of Cellular Membranology, A.A. Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Dariia Dryn
- Department of Cellular Membranology, A.A. Bogomoletz Institute of Physiology, Kyiv, Ukraine
| | - Alexander Zholos
- Department of Biophysics and Medical Informatics, Educational and Scientific Centre "Institute of Biology and Medicine", Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
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20
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Jiang L, Li J, Reilly S, Xin H, Guo N, Zhang X. Role of organellar Ca2+-activated K+ channels in disease development. Life Sci 2023; 316:121433. [PMID: 36708987 DOI: 10.1016/j.lfs.2023.121433] [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: 11/09/2022] [Revised: 01/16/2023] [Accepted: 01/19/2023] [Indexed: 01/27/2023]
Abstract
The organellar Ca2+-activated K+ channels share a similar ability to transfer the alteration of Ca2+ concentration to membrane conductance of potassium. Multiple effects of Ca2+-activated K+ channels on cell metabolism and complex signaling pathways during organ development have been explored. The organellar Ca2+-activated K+ channels are able to control the ionic equilibrium and are always associated with oxidative stress in different organelles and the whole cells. Some drugs targeting Ca2+-activated K+ channels have been tested for various diseases in clinical trials. In this review, the known roles of organellar Ca2+-activated K+ channels were described, and their effects on different diseases, particularly on diabetes, cardiovascular diseases, and neurological diseases were discussed. It was attempted to summarize the currently known operational modes with the involvement of organellar Ca2+-activated K+ channels. This review may assist scholars to more comprehensively understand organellar Ca2+-activated K+ channels and related diseases.
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Affiliation(s)
- Lan Jiang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Jiawei Li
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Hong Xin
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China
| | - Nan Guo
- Department of Pharmacy, Minhang hospital, Fudan University, Shanghai, China.
| | - Xuemei Zhang
- Department of Pharmacology, School of Pharmacy, Fudan University, Shanghai, China.
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21
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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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22
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Wang ZW, Trussell LO, Vedantham K. Regulation of Neurotransmitter Release by K + Channels. ADVANCES IN NEUROBIOLOGY 2023; 33:305-331. [PMID: 37615872 DOI: 10.1007/978-3-031-34229-5_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
K+ channels play potent roles in the process of neurotransmitter release by influencing the action potential waveform and modulating neuronal excitability and release probability. These diverse effects of K+ channel activation are ensured by the wide variety of K+ channel genes and their differential expression in different cell types. Accordingly, a variety of K+ channels have been implicated in regulating neurotransmitter release, including the Ca2+- and voltage-gated K+ channel Slo1 (also known as BK channel), voltage-gated K+ channels of the Kv3 (Shaw-type), Kv1 (Shaker-type), and Kv7 (KCNQ) families, G-protein-gated inwardly rectifying K+ (GIRK) channels, and SLO-2 (a Ca2+-. Cl-, and voltage-gated K+ channel in C. elegans). These channels vary in their expression patterns, subcellular localization, and biophysical properties. Their roles in neurotransmitter release may also vary depending on the synapse and physiological or experimental conditions. This chapter summarizes key findings about the roles of K+ channels in regulating neurotransmitter release.
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Affiliation(s)
- Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Laurence O Trussell
- Oregon Hearing Research Center & Vollum Institute, Oregon Health and Science University, Portland, OR, USA
| | - Kiranmayi Vedantham
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
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23
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Abstract
Lysosomes are acidic membrane-bound organelles that use hydrolytic enzymes to break down material through pathways such as endocytosis, phagocytosis, mitophagy, and autophagy. To function properly, intralysosomal environments are strictly controlled by a set of integral membrane proteins such as ion channels and transporters. Potassium ion (K+) channels are a large and diverse family of membrane proteins that control K+ flux across both the plasma membrane and intracellular membranes. In the plasma membrane, they are essential in both excitable and non-excitable cells for the control of membrane potential and cell signaling. However, our understanding of intracellular K+ channels is very limited. In this review, we summarize the recent development in studies of K+ channels in the lysosome. We focus on their characterization, potential roles in maintaining lysosomal membrane potential and lysosomal function, and pathological implications.
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Affiliation(s)
- Peng Huang
- Collaborative Innovation Center for Biomedicine, School of Clinical Medicine, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Mengnan Xu
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, Halifax, NS, Canada
| | - Yi Wu
- Collaborative Innovation Center for Biomedicine, School of Clinical Medicine, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Alia Kazim Rizvi Syeda
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, Halifax, NS, Canada
| | - Xian-Ping Dong
- Department of Physiology and Biophysics, Dalhousie University, Sir Charles Tupper Medical Building, Halifax, NS, Canada.
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24
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Kollewe A, Schwarz Y, Oleinikov K, Raza A, Haupt A, Wartenberg P, Wyatt A, Boehm U, Ectors F, Bildl W, Zolles G, Schulte U, Bruns D, Flockerzi V, Fakler B. Subunit composition, molecular environment, and activation of native TRPC channels encoded by their interactomes. Neuron 2022; 110:4162-4175.e7. [PMID: 36257322 DOI: 10.1016/j.neuron.2022.09.029] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/15/2022] [Accepted: 09/23/2022] [Indexed: 12/24/2022]
Abstract
In the mammalian brain TRPC channels, a family of Ca2+-permeable cation channels, are involved in a variety of processes from neuronal growth and synapse formation to transmitter release, synaptic transmission and plasticity. The molecular appearance and operation of native TRPC channels, however, remained poorly understood. Here, we used high-resolution proteomics to show that TRPC channels in the rodent brain are macro-molecular complexes of more than 1 MDa in size that result from the co-assembly of the tetrameric channel core with an ensemble of interacting proteins (interactome). The core(s) of TRPC1-, C4-, and C5-containing channels are mostly heteromers with defined stoichiometries for each subtype, whereas TRPC3, C6, and C7 preferentially form homomers. In addition, TRPC1/C4/C5 channels may co-assemble with the metabotropic glutamate receptor mGluR1, thus guaranteeing both specificity and reliability of channel activation via the phospholipase-Ca2+ pathway. Our results unveil the subunit composition of native TRPC channels and resolve the molecular details underlying their activation.
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Affiliation(s)
- Astrid Kollewe
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Yvonne Schwarz
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Katharina Oleinikov
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Ahsan Raza
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Alexander Haupt
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Philipp Wartenberg
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Amanda Wyatt
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Ulrich Boehm
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany
| | - Fabien Ectors
- Transgenic facility, FARAH Research Center, Faculty of Veterinary Medicine, University of Liège, 4000 Liège, Belgium
| | - Wolfgang Bildl
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Gerd Zolles
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany
| | - Uwe Schulte
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, Schänzlestr. 18, 79104 Freiburg, Germany
| | - Dieter Bruns
- Institute of Physiology, Center for Integrative Physiology and Molecular Medicine, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimental and Clinical Pharmacology and Toxicology, PZMS, Saarland University, 66421 Homburg, Germany.
| | - Bernd Fakler
- Institute of Physiology, Faculty of Medicine, University of Freiburg, Hermann-Herder-Str. 7, 79104 Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, Schänzlestr. 18, 79104 Freiburg, Germany; Center for Basics in NeuroModulation, Breisacherstr. 4, 79106 Freiburg, Germany.
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25
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Bartels P, Salveson I, Coleman AM, Anderson DE, Jeng G, Estrada-Tobar ZM, Man KNM, Yu Q, Kuzmenkina E, Nieves-Cintron M, Navedo MF, Horne MC, Hell JW, Ames JB. Half-calcified calmodulin promotes basal activity and inactivation of the L-type calcium channel Ca V1.2. J Biol Chem 2022; 298:102701. [PMID: 36395884 PMCID: PMC9764201 DOI: 10.1016/j.jbc.2022.102701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 10/30/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
The L-type Ca2+ channel CaV1.2 controls gene expression, cardiac contraction, and neuronal activity. Calmodulin (CaM) governs CaV1.2 open probability (Po) and Ca2+-dependent inactivation (CDI) but the mechanisms remain unclear. Here, we present electrophysiological data that identify a half Ca2+-saturated CaM species (Ca2/CaM) with Ca2+ bound solely at the third and fourth EF-hands (EF3 and EF4) under resting Ca2+ concentrations (50-100 nM) that constitutively preassociates with CaV1.2 to promote Po and CDI. We also present an NMR structure of a complex between the CaV1.2 IQ motif (residues 1644-1665) and Ca2/CaM12', a calmodulin mutant in which Ca2+ binding to EF1 and EF2 is completely disabled. We found that the CaM12' N-lobe does not interact with the IQ motif. The CaM12' C-lobe bound two Ca2+ ions and formed close contacts with IQ residues I1654 and Y1657. I1654A and Y1657D mutations impaired CaM binding, CDI, and Po, as did disabling Ca2+ binding to EF3 and EF4 in the CaM34 mutant when compared to WT CaM. Accordingly, a previously unappreciated Ca2/CaM species promotes CaV1.2 Po and CDI, identifying Ca2/CaM as an important mediator of Ca signaling.
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Affiliation(s)
- Peter Bartels
- Department of Pharmacology, University of California, Davis, California, USA
| | - Ian Salveson
- Department of Chemistry, University of California, Davis, California, USA
| | - Andrea M Coleman
- Department of Pharmacology, University of California, Davis, California, USA; Department of Chemistry, University of California, Davis, California, USA
| | - David E Anderson
- Department of Chemistry, University of California, Davis, California, USA
| | - Grace Jeng
- Department of Pharmacology, University of California, Davis, California, USA
| | | | - Kwun Nok Mimi Man
- Department of Pharmacology, University of California, Davis, California, USA
| | - Qinhong Yu
- Department of Chemistry, University of California, Davis, California, USA
| | - Elza Kuzmenkina
- Center for Pharmacology, University of Cologne, Cologne, Germany
| | | | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, California, USA
| | - Mary C Horne
- Department of Pharmacology, University of California, Davis, California, USA.
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, California, USA.
| | - James B Ames
- Department of Chemistry, University of California, Davis, California, USA.
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26
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Dorman DB, Blackwell KT. Synaptic Plasticity Is Predicted by Spatiotemporal Firing Rate Patterns and Robust to In Vivo-like Variability. Biomolecules 2022; 12:1402. [PMID: 36291612 PMCID: PMC9599115 DOI: 10.3390/biom12101402] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/13/2022] [Accepted: 09/28/2022] [Indexed: 11/22/2022] Open
Abstract
Synaptic plasticity, the experience-induced change in connections between neurons, underlies learning and memory in the brain. Most of our understanding of synaptic plasticity derives from in vitro experiments with precisely repeated stimulus patterns; however, neurons exhibit significant variability in vivo during repeated experiences. Further, the spatial pattern of synaptic inputs to the dendritic tree influences synaptic plasticity, yet is not considered in most synaptic plasticity rules. Here, we investigate how spatiotemporal synaptic input patterns produce plasticity with in vivo-like conditions using a data-driven computational model with a plasticity rule based on calcium dynamics. Using in vivo spike train recordings as inputs to different size clusters of spines, we show that plasticity is strongly robust to trial-to-trial variability of spike timing. In addition, we derive general synaptic plasticity rules describing how spatiotemporal patterns of synaptic inputs control the magnitude and direction of plasticity. Synapses that strongly potentiated have greater firing rates and calcium concentration later in the trial, whereas strongly depressing synapses have hiring firing rates early in the trial. The neighboring synaptic activity influences the direction and magnitude of synaptic plasticity, with small clusters of spines producing the greatest increase in synaptic strength. Together, our results reveal that calcium dynamics can unify diverse plasticity rules and reveal how spatiotemporal firing rate patterns control synaptic plasticity.
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Affiliation(s)
- Daniel B. Dorman
- Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, VA 22030, USA
| | - Kim T. Blackwell
- Interdisciplinary Program in Neuroscience, George Mason University, Fairfax, VA 22030, USA
- Department of Bioengineering, Volgenau School of Engineering, George Mason University, Fairfax, VA 22030, USA
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27
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Pottosin I, Dobrovinskaya O. Major vacuolar TPC1 channel in stress signaling: what matters, K +, Ca 2+ conductance or an ion-flux independent mechanism? STRESS BIOLOGY 2022; 2:31. [PMID: 37676554 PMCID: PMC10441842 DOI: 10.1007/s44154-022-00055-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 07/29/2022] [Indexed: 09/08/2023]
Abstract
Two-pore cation channel, TPC1, is ubiquitous in the vacuolar membrane of terrestrial plants and mediates the long distance signaling upon biotic and abiotic stresses. It possesses a wide pore, which transports small mono- and divalent cations. K+ is transported more than 10-fold faster than Ca2+, which binds with a higher affinity within the pore. Key pore residues, responsible for Ca2+ binding, have been recently identified. There is also a substantial progress in the mechanistic and structural understanding of the plant TPC1 gating by membrane voltage and cytosolic and luminal Ca2+. Collectively, these gating factors at resting conditions strongly reduce the potentially lethal Ca2+ leak from the vacuole. Such tight control is impressive, bearing in mind high unitary conductance of the TPC1 and its abundance, with thousands of active channel copies per vacuole. But it remains a mystery how this high threshold is overcome upon signaling, and what type of signal is emitted by TPC1, whether it is Ca2+ or electrical one, or a transduction via protein conformational change, independent on ion conductance. Here we discuss non-exclusive scenarios for the TPC1 integration into Ca2+, ROS and electrical signaling.
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Affiliation(s)
- Igor Pottosin
- Biomedical Center, University of Colima, 28045, Colima, Mexico.
- International Research Centre for Environmental Membrane Biology, Foshan University, Foshan, 528041, China.
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28
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Kleene SJ. Regenerative Calcium Currents in Renal Primary Cilia. Front Physiol 2022; 13:894518. [PMID: 35620606 PMCID: PMC9127361 DOI: 10.3389/fphys.2022.894518] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/18/2022] [Indexed: 11/13/2022] Open
Abstract
Polycystic kidney disease (PKD) is a leading cause of end-stage renal disease. PKD arises from mutations in proteins, one a Ca2+-conducting channel, expressed in the primary cilia of renal epithelial cells. A common hypothesis is that Ca2+ entering through ciliary ion channels may reduce cystogenesis. The cilia have at least two Ca2+-conducting channels: polycystin-2 (PC2) and TRPV4 (transient receptor potential (TRP) cation channel, subfamily V, member 4), but how substantially they can increase intraciliary Ca2+ is unknown. By recording channel activities in isolated cilia, conditions are identified under which the channels can increase free Ca2+ within the cilium by at least 500-fold through regenerative (positive-feedback) signaling. Ca2+ that has entered through a channel can activate the channel internally, which increases the Ca2+ influx, and so on. Regenerative signaling is favored when the concentration of the Ca2+ buffer is reduced or when a slower buffer is used. Under such conditions, the Ca2+ that enters the cilium through a single PC2 channel is sufficient to almost fully activate that same channel. Regenerative signaling is not detectable with reduced external Ca2+. Reduced buffering also allows regenerative signaling through TRPV4 channels, but not through TRPM4 (TRP subfamily M, member 4) channels, which are activated by Ca2+ but do not conduct it. On a larger scale, Ca2+ that enters through TRPV4 channels can cause secondary activation of PC2 channels. I discuss the likelihood of regenerative ciliary Ca2+ signaling in vivo, a possible mechanism for its activation, and how it might relate to cystogenesis.
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Affiliation(s)
- Steven J. Kleene
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, OH, United States
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29
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Becchetti A, Duranti C, Arcangeli A. Dynamics and physiological meaning of complexes between ion channels and integrin receptors: the case of Kv11.1. Am J Physiol Cell Physiol 2022; 322:C1138-C1150. [PMID: 35442831 DOI: 10.1152/ajpcell.00107.2022] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The cellular functions are regulated by a complex interplay of diffuse and local signals. Experimental work in cell physiology has led to recognize that understanding a cell's dynamics requires a deep comprehension of local fluctuations of cytosolic regulators. Macromolecular complexes are major determinants of local signaling. Multi-enzyme assemblies limit the diffusion restriction to reaction kinetics by direct exchange of metabolites. Likewise, close coupling of ion channels and transporters modulate the ion concentration around a channel mouth or transporter binding site. Extreme signal locality is brought about by conformational coupling between membrane proteins, as is typical of mechanotransduction. A paradigmatic case is integrin-mediated cell adhesion. Sensing the extracellular microenvironment and providing an appropriate response is essential in growth and development and has innumerable pathological implications. The process involves bidirectional signal transduction by complex supra-molecular structures that link integrin receptors to ion channels and transporters, growth factor receptors, cytoskeletal elements and other regulatory elements. The dynamics of such complexes is only beginning to be understood. A thoroughly studied example is the association between integrin receptors and the voltage-gated K+ channels Kv11.1. These channels are widely expressed in early embryos, where their physiological roles are poorly understood and apparently different from the shaping of action potential firing in the adult. Hints about these roles come from studies in cancer cells, where Kv11.1 is often overexpressed and appears to re-assume functions, such as controlling cell proliferation/differentiation, apoptosis and migration. Kv11.1 is implicated in these processes through its linking to integrin subunits.
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Affiliation(s)
- Andrea Becchetti
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milano, Italy
| | - Claudia Duranti
- Department of Experimental and Clinical Medicine. University of Florence, Firenze, Italy
| | - Annarosa Arcangeli
- Department of Experimental and Clinical Medicine. University of Florence, Firenze, Italy
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30
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Dong P, Zhang Y, Hunanyan AS, Mikati MA, Cui J, Yang H. Neuronal mechanism of a BK channelopathy in absence epilepsy and dyskinesia. Proc Natl Acad Sci U S A 2022; 119:e2200140119. [PMID: 35286197 PMCID: PMC8944272 DOI: 10.1073/pnas.2200140119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/02/2022] [Indexed: 12/13/2022] Open
Abstract
A growing number of gain-of-function (GOF) BK channelopathies have been identified in patients with epilepsy and movement disorders. Nevertheless, the underlying pathophysiology and corresponding therapeutics remain obscure. Here, we utilized a knock-in mouse model carrying human BK-D434G channelopathy to investigate the neuronal mechanism of BK GOF in the pathogenesis of epilepsy and dyskinesia. The BK-D434G mice manifest the clinical features of absence epilepsy and exhibit severe motor deficits and dyskinesia-like behaviors. The cortical pyramidal neurons and cerebellar Purkinje cells from the BK-D434G mice show hyperexcitability, which likely contributes to the pathogenesis of absence seizures and paroxysmal dyskinesia. A BK channel blocker, paxilline, potently suppresses BK-D434G–induced hyperexcitability and effectively mitigates absence seizures and locomotor deficits in mice. Our study thus uncovered a neuronal mechanism of BK GOF in absence epilepsy and dyskinesia. Our findings also suggest that BK inhibition is a promising therapeutic strategy for mitigating BK GOF-induced neurological disorders.
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Affiliation(s)
- Ping Dong
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710
| | - Yang Zhang
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710
| | - Arsen S. Hunanyan
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710
| | - Mohamad A. Mikati
- Department of Pediatrics, Duke University Medical Center, Durham, NC 27710
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710
| | - Jianmin Cui
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130
| | - Huanghe Yang
- Department of Biochemistry, Duke University Medical Center, Durham, NC 27710
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710
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31
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Gao L, Zhao J, Ardiel EL, Hall Q, Nurrish S, Kaplan JM. Shank promotes action potential repolarization by recruiting BK channels to calcium microdomains. eLife 2022; 11:75140. [PMID: 35266450 PMCID: PMC8937234 DOI: 10.7554/elife.75140] [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: 10/30/2021] [Accepted: 03/09/2022] [Indexed: 11/13/2022] Open
Abstract
Mutations altering the scaffolding protein Shank are linked to several psychiatric disorders, and to synaptic and behavioral defects in mice. Among its many binding partners, Shank directly binds CaV1 voltage activated calcium channels. Here we show that the C. elegans SHN-1/Shank promotes CaV1 coupling to calcium activated potassium channels. Mutations inactivating SHN-1, and those preventing SHN-1 binding to EGL-19/CaV1 all increase action potential durations in body muscles. Action potential repolarization is mediated by two classes of potassium channels: SHK-1/KCNA and SLO-1 and SLO-2 BK channels. BK channels are calcium-dependent, and their activation requires tight coupling to EGL-19/CaV1 channels. SHN-1's effects on AP duration are mediated by changes in BK channels. In shn-1 mutants, SLO-2 currents and channel clustering are significantly decreased in both body muscles and neurons. Finally, increased and decreased shn-1 gene copy number produce similar changes in AP width and SLO-2 current. Collectively, these results suggest that an important function of Shank is to promote microdomain coupling of BK with CaV1.
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Affiliation(s)
- Luna Gao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Jian Zhao
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Evan L Ardiel
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Qi Hall
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Stephen Nurrish
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
| | - Joshua M Kaplan
- Department of Molecular Biology, Massachusetts General Hospital, Boston, United States
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32
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Lanzetti S, Di Biase V. Small Molecules as Modulators of Voltage-Gated Calcium Channels in Neurological Disorders: State of the Art and Perspectives. Molecules 2022; 27:1312. [PMID: 35209100 PMCID: PMC8879281 DOI: 10.3390/molecules27041312] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2022] [Revised: 02/11/2022] [Accepted: 02/11/2022] [Indexed: 01/03/2023] Open
Abstract
Voltage-gated calcium channels (VGCCs) are widely expressed in the brain, heart and vessels, smooth and skeletal muscle, as well as in endocrine cells. VGCCs mediate gene transcription, synaptic and neuronal structural plasticity, muscle contraction, the release of hormones and neurotransmitters, and membrane excitability. Therefore, it is not surprising that VGCC dysfunction results in severe pathologies, such as cardiovascular conditions, neurological and psychiatric disorders, altered glycemic levels, and abnormal smooth muscle tone. The latest research findings and clinical evidence increasingly show the critical role played by VGCCs in autism spectrum disorders, Parkinson's disease, drug addiction, pain, and epilepsy. These findings outline the importance of developing selective calcium channel inhibitors and modulators to treat such prevailing conditions of the central nervous system. Several small molecules inhibiting calcium channels are currently used in clinical practice to successfully treat pain and cardiovascular conditions. However, the limited palette of molecules available and the emerging extent of VGCC pathophysiology require the development of additional drugs targeting these channels. Here, we provide an overview of the role of calcium channels in neurological disorders and discuss possible strategies to generate novel therapeutics.
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Affiliation(s)
| | - Valentina Di Biase
- Institute of Pharmacology, Department of Medical Statistics, Informatics and Health Economics, Medical University of Innsbruck, Peter-Mayr Strasse 1, A-6020 Innsbruck, Austria;
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Ion Channel Partnerships: Odd and Not-So-Odd Couples Controlling Neuronal Ion Channel Function. Int J Mol Sci 2022; 23:ijms23041953. [PMID: 35216068 PMCID: PMC8878034 DOI: 10.3390/ijms23041953] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/05/2022] [Accepted: 02/08/2022] [Indexed: 12/04/2022] Open
Abstract
The concerted function of the large number of ion channels expressed in excitable cells, including brain neurons, shapes diverse signaling events by controlling the electrical properties of membranes. It has long been recognized that specific groups of ion channels are functionally coupled in mediating ionic fluxes that impact membrane potential, and that these changes in membrane potential impact ion channel gating. Recent studies have identified distinct sets of ion channels that can also physically and functionally associate to regulate the function of either ion channel partner beyond that afforded by changes in membrane potential alone. Here, we review canonical examples of such ion channel partnerships, in which a Ca2+ channel is partnered with a Ca2+-activated K+ channel to provide a dedicated route for efficient coupling of Ca2+ influx to K+ channel activation. We also highlight examples of non-canonical ion channel partnerships between Ca2+ channels and voltage-gated K+ channels that are not intrinsically Ca2+ sensitive, but whose partnership nonetheless yields enhanced regulation of one or the other ion channel partner. We also discuss how these ion channel partnerships can be shaped by the subcellular compartments in which they are found and provide perspectives on how recent advances in techniques to identify proteins in close proximity to one another in native cells may lead to an expanded knowledge of other ion channel partnerships.
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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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Dixon RE, Navedo MF, Binder MD, Santana LF. Mechanisms and Physiological Implications of Cooperative Gating of Ion Channels Clusters. Physiol Rev 2021; 102:1159-1210. [PMID: 34927454 DOI: 10.1152/physrev.00022.2021] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Ion channels play a central role in the regulation of nearly every cellular process. Dating back to the classic 1952 Hodgkin-Huxley model of the generation of the action potential, ion channels have always been thought of as independent agents. A myriad of recent experimental findings exploiting advances in electrophysiology, structural biology, and imaging techniques, however, have posed a serious challenge to this long-held axiom as several classes of ion channels appear to open and close in a coordinated, cooperative manner. Ion channel cooperativity ranges from variable-sized oligomeric cooperative gating in voltage-gated, dihydropyridine-sensitive Cav1.2 and Cav1.3 channels to obligatory dimeric assembly and gating of voltage-gated Nav1.5 channels. Potassium channels, transient receptor potential channels, hyperpolarization cyclic nucleotide-activated channels, ryanodine receptors (RyRs), and inositol trisphosphate receptors (IP3Rs) have also been shown to gate cooperatively. The implications of cooperative gating of these ion channels range from fine tuning excitation-contraction coupling in muscle cells to regulating cardiac function and vascular tone, to modulation of action potential and conduction velocity in neurons and cardiac cells, and to control of pace-making activity in the heart. In this review, we discuss the mechanisms leading to cooperative gating of ion channels, their physiological consequences and how alterations in cooperative gating of ion channels may induce a range of clinically significant pathologies.
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Affiliation(s)
- Rose Ellen Dixon
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
| | - Manuel F Navedo
- Department of Pharmacology, University of California, Davis, CA, United States
| | - Marc D Binder
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, United States
| | - L Fernando Santana
- Department of Physiology and Membrane Biology, University of California, Davis, CA, United States
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Duncan PJ, Fazli M, Romanò N, Le Tissier P, Bertram R, Shipston MJ. Chronic stress facilitates bursting electrical activity in pituitary corticotrophs. J Physiol 2021; 600:313-332. [PMID: 34855218 DOI: 10.1113/jp282367] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 11/18/2021] [Indexed: 11/08/2022] Open
Abstract
Coordination of an appropriate stress response is dependent upon anterior pituitary corticotroph excitability in response to hypothalamic secretagogues and glucocorticoid negative feedback. A key determinant of corticotroph excitability is large conductance calcium- and voltage-activated (BK) potassium channels that are critical for promoting corticotrophin-releasing hormone (CRH)-induced bursting that enhances adrenocorticotrophic hormone secretion. Previous studies revealed hypothalamic-pituitary-adrenal axis hyperexcitability following chronic stress (CS) is partly a function of increased corticotroph output. Thus, we hypothesise that chronic stress promotes corticotroph excitability through a BK-dependent mechanism. Corticotrophs from CS mice displayed significant increase in spontaneous bursting, which was suppressed by the BK blocker paxilline. Mathematical modelling reveals that the time constant of BK channel activation, plus properties and proportion of BK channels functionally coupled to L-type Ca2+ channels determines bursting activity. Surprisingly, CS corticotrophs (but not unstressed) display CRH-induced bursting even when the majority of BK channels are inhibited by paxilline, which modelling suggests is a consequence of the stochastic behaviour of a small number of BK channels coupled to L-type Ca2+ channels. Our data reveal that changes in the stochastic behaviour of a small number of BK channels can finely tune corticotroph excitability through stress-induced changes in BK channel properties. Importantly, regulation of BK channel function is highly context dependent allowing dynamic control of corticotroph excitability over a large range of time domains and physiological challenges in health and disease. This is likely to occur in other BK-expressing endocrine cells, with important implications for the physiological processes they regulate and the potential for therapy. KEY POINTS: Chronic stress (CS) is predicted to modify the electrical excitability of anterior pituitary corticotrophs. Electrophysiological recordings from isolated corticotrophs from CS male mice display spontaneous electrical bursting behaviour compared to the tonic spiking behaviour of unstressed corticotrophs. The increased spontaneous bursting from CS corticotrophs is BK-dependent and mathematical modelling reveals that the time constant of activation, properties and proportion of BK channels functionally coupled to L-type calcium channels determines the promotion of bursting activity. CS (but not unstressed) corticotrophs display corticotrophin-releasing hormone-induced bursting even when the majority of BK channels are pharmacologically inhibited, which can be explained by the stochastic behaviour of a small number of BK channels with distinct properties. Corticotroph excitability can be finely tuned by the stochastic behaviour of a small number of BK channels dependent on their properties and functional co-localisation with L-type calcium channels to control corticotroph excitability over diverse time domains and physiological challenges.
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Affiliation(s)
- Peter J Duncan
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Mehran Fazli
- Department of Mathematics, Florida State University, Tallahassee, FL, USA
| | - Nicola Romanò
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Paul Le Tissier
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
| | - Richard Bertram
- Department of Mathematics, Florida State University, Tallahassee, FL, USA.,Programs in Neuroscience and Molecular Biophysics, Florida State University, Tallahassee, FL, USA
| | - Michael J Shipston
- Centre for Discovery Brain Sciences, Edinburgh Medical School: Biomedical Sciences, University of Edinburgh, Edinburgh, UK
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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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Sancho M, Kyle BD. The Large-Conductance, Calcium-Activated Potassium Channel: A Big Key Regulator of Cell Physiology. Front Physiol 2021; 12:750615. [PMID: 34744788 PMCID: PMC8567177 DOI: 10.3389/fphys.2021.750615] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/29/2021] [Indexed: 12/01/2022] Open
Abstract
Large-conductance Ca2+-activated K+ channels facilitate the efflux of K+ ions from a variety of cells and tissues following channel activation. It is now recognized that BK channels undergo a wide range of pre- and post-translational modifications that can dramatically alter their properties and function. This has downstream consequences in affecting cell and tissue excitability, and therefore, function. While finding the “silver bullet” in terms of clinical therapy has remained elusive, ongoing research is providing an impressive range of viable candidate proteins and mechanisms that associate with and modulate BK channel activity, respectively. Here, we provide the hallmarks of BK channel structure and function generally, and discuss important milestones in the efforts to further elucidate the diverse properties of BK channels in its many forms.
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Affiliation(s)
- Maria Sancho
- Department of Pharmacology, University of Vermont, Burlington, VT, United States
| | - Barry D Kyle
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Saskatchewan, Saskatoon, SK, Canada
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The Control of Rat Hippocampal Gamma Oscillation Strength by BK Channel Activity. Neuroscience 2021; 475:220-228. [PMID: 34509547 DOI: 10.1016/j.neuroscience.2021.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 09/01/2021] [Accepted: 09/02/2021] [Indexed: 11/20/2022]
Abstract
Neuronal network oscillations in the gamma frequency band (30-80 Hz, γ oscillations) are associated with the higher brain functions such as perception, attention, learning and memory. BK channels mediate rapid repolarization and fast afterhyperpolarization in neurons and control neuronal excitability, and potentially control hippocampal γ oscillations. In this study, we examined the effects of modulating BK channels on hippocampal γ oscillations in the absence or presence of Ca2+ influx through voltage-gated Ca2+ channels (VGCC) or Ca2+-permeable AMPA receptors (CP-AMPAR). We found that blocking BK channels enhanced γ power, without affecting oscillation frequency or regularity, suggesting that BK channel activity suppresses γ oscillations. Blocking either VGCC or CP-AMPAR itself enhanced γ power, and completely occluded the effect of BK channel blockers on γ oscillations, whereas blocking BK channels first could not prevent a further γ power increase upon blockade of either CP-AMPAR or VGCC. We propose that Ca2+ influx through VGCC or CP-AMPAR during γ oscillations, cause membrane BK channel activation and regulate hippocampal γ oscillation strength by negative feedback.
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40
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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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NMDA receptor-BK channel coupling regulates synaptic plasticity in the barrel cortex. Proc Natl Acad Sci U S A 2021; 118:2107026118. [PMID: 34453004 PMCID: PMC8536339 DOI: 10.1073/pnas.2107026118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
N-methyl-D-aspartate (NMDA) receptors are critical triggers for neuronal plasticity. We show that large-conductance Ca2+- and voltage-gated K+ (BK) channels serve as feedback regulators of NMDA receptor–mediated calcium influx to shape NMDA receptor–mediated synaptic potentials and consequently elevate the threshold for triggering plasticity at a subset of synapses. Postsynaptic N-methyl-D-aspartate receptors (NMDARs) are crucial mediators of synaptic plasticity due to their ability to act as coincidence detectors of presynaptic and postsynaptic neuronal activity. However, NMDARs exist within the molecular context of a variety of postsynaptic signaling proteins, which can fine-tune their function. Here, we describe a form of NMDAR suppression by large-conductance Ca2+- and voltage-gated K+ (BK) channels in the basal dendrites of a subset of barrel cortex layer 5 pyramidal neurons. We show that NMDAR activation increases intracellular Ca2+ in the vicinity of BK channels, thus activating K+ efflux and strong negative feedback inhibition. We further show that neurons exhibiting such NMDAR–BK coupling serve as high-pass filters for incoming synaptic inputs, precluding the induction of spike timing–dependent plasticity. Together, these data suggest that NMDAR-localized BK channels regulate synaptic integration and provide input-specific synaptic diversity to a thalamocortical circuit.
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Abstract
Neurons are highly specialized cells equipped with a sophisticated molecular machinery for the reception, integration, conduction and distribution of information. The evolutionary origin of neurons remains unsolved. How did novel and pre-existing proteins assemble into the complex machinery of the synapse and of the apparatus conducting current along the neuron? In this review, the step-wise assembly of functional modules in neuron evolution serves as a paradigm for the emergence and modification of molecular machinery in the evolution of cell types in multicellular organisms. The pre-synaptic machinery emerged through modification of calcium-regulated large vesicle release, while the postsynaptic machinery has different origins: the glutamatergic postsynapse originated through the fusion of a sensory signaling module and a module for filopodial outgrowth, while the GABAergic postsynapse incorporated an ancient actin regulatory module. The synaptic junction, in turn, is built around two adhesion modules controlled by phosphorylation, which resemble septate and adherens junctions. Finally, neuronal action potentials emerged via a series of duplications and modifications of voltage-gated ion channels. Based on these origins, key molecular innovations are identified that led to the birth of the first neuron in animal evolution.
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Fyke W, Velinov M. FMR1 and Autism, an Intriguing Connection Revisited. Genes (Basel) 2021; 12:genes12081218. [PMID: 34440392 PMCID: PMC8394635 DOI: 10.3390/genes12081218] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 08/03/2021] [Accepted: 08/04/2021] [Indexed: 12/27/2022] Open
Abstract
Autism Spectrum Disorder (ASD) represents a distinct phenotype of behavioral dysfunction that includes deficiencies in communication and stereotypic behaviors. ASD affects about 2% of the US population. It is a highly heritable spectrum of conditions with substantial genetic heterogeneity. To date, mutations in over 100 genes have been reported in association with ASD phenotypes. Fragile X syndrome (FXS) is the most common single-gene disorder associated with ASD. The gene associated with FXS, FMR1 is located on chromosome X. Accordingly, the condition has more severe manifestations in males. FXS results from the loss of function of FMR1 due to the expansion of an unstable CGG repeat located in the 5'' untranslated region of the gene. About 50% of the FXS males and 20% of the FXS females meet the Diagnostic Statistical Manual 5 (DSM-5) criteria for ASD. Among the individuals with ASD, about 3% test positive for FXS. FMRP, the protein product of FMR1, is a major gene regulator in the central nervous system. Multiple pathways regulated by FMRP are found to be dysfunctional in ASD patients who do not have FXS. Thus, FXS presents the opportunity to study cellular phenomena that may have wider applications in the management of ASD and to develop new strategies for ASD therapy.
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Affiliation(s)
- William Fyke
- SUNY Downstate Medical Center, SUNY Downstate College of Medicine, Brooklyn, NY 11203, USA;
- Graduate Program in Neural and Behavioral Science, SUNY Downstate Medical Center, Brooklyn, NY 11203, USA
| | - Milen Velinov
- Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ 08901, USA
- Child Health Institute of New Jersey, New Brunswick, NJ 08901, USA
- Correspondence:
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Biet M, Dansereau M, Sarret P, Dumaine R. The neuronal potassium current I A is a potential target for pain during chronic inflammation. Physiol Rep 2021; 9:e14975. [PMID: 34405579 PMCID: PMC8371350 DOI: 10.14814/phy2.14975] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/10/2021] [Accepted: 06/25/2021] [Indexed: 11/24/2022] Open
Abstract
Voltage-gated ion channels play a key role in the action potential (AP) initiation and its propagation in sensory neurons. Modulation of their activity during chronic inflammation creates a persistent pain state. In this study, we sought to determine how peripheral inflammation caused by complete Freund's adjuvant (CFA) alters the fast sodium (INa ), L-type calcium (ICaL ), and potassium (IK ) currents in primary afferent fibers to increase nociception. In our model, intraplantar administration of CFA induced mechanical allodynia and thermal hyperalgesia at day 14 post-injection. Using whole-cell patch-clamp recording in dissociated small (C), medium (Aδ), and large-sized (Aβ) rat dorsal root ganglion (DRG) neurons, we found that CFA prolonged the AP duration and increased the amplitude of the tetrodotoxin-resistant (TTX-r) INa in Aβ fibers. In addition, CFA accelerated the recovery of INa from inactivation in C and Aδ nociceptive fibers but enhanced the late sodium current (INaL ) only in Aδ and Aβ neurons. Inflammation similarly reduced the amplitude of ICaL in each neuronal cell type. Fourteen days after injection, CFA reduced both components of IK (IKdr and IA ) in Aδ fibers. We also found that IA was significantly larger in C and Aδ neurons in normal conditions and during chronic inflammation. Our data, therefore, suggest that targeting the transient potassium current IA represents an efficient way to shift the balance toward antinociception during inflammation, since its activation will selectively decrease the AP duration in nociceptive fibers. Altogether, our data indicate that complex interactions between IK , INa , and ICaL reduce pain threshold by concomitantly enhancing the activity of nociceptive neurons and reducing the inhibitory action of Aβ fibers during chronic inflammation.
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MESH Headings
- Action Potentials
- Animals
- Calcium Channels, L-Type/metabolism
- Cells, Cultured
- Ganglia, Spinal/cytology
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/physiology
- Male
- Neurons, Afferent/drug effects
- Neurons, Afferent/metabolism
- Neurons, Afferent/physiology
- Nociception
- Nociceptive Pain/metabolism
- Nociceptive Pain/physiopathology
- Potassium Channels, Voltage-Gated/metabolism
- Rats
- Rats, Sprague-Dawley
- Sodium Channel Blockers/pharmacology
- Sodium Channels/metabolism
- Tetrodotoxin/pharmacology
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Affiliation(s)
- Michael Biet
- Département de Pharmacologie et PhysiologieInstitut de pharmacologie de SherbrookeCentre de Recherche du Centre Hospitalier Universitaire de SherbrookeFaculté de médecine et des Sciences de la SantéUniversité de SherbrookeSherbrookeQuébecCanada
| | - Marc‐André Dansereau
- Département de Pharmacologie et PhysiologieInstitut de pharmacologie de SherbrookeCentre de Recherche du Centre Hospitalier Universitaire de SherbrookeFaculté de médecine et des Sciences de la SantéUniversité de SherbrookeSherbrookeQuébecCanada
| | - Philippe Sarret
- Département de Pharmacologie et PhysiologieInstitut de pharmacologie de SherbrookeCentre de Recherche du Centre Hospitalier Universitaire de SherbrookeFaculté de médecine et des Sciences de la SantéUniversité de SherbrookeSherbrookeQuébecCanada
| | - Robert Dumaine
- Département de Pharmacologie et PhysiologieInstitut de pharmacologie de SherbrookeCentre de Recherche du Centre Hospitalier Universitaire de SherbrookeFaculté de médecine et des Sciences de la SantéUniversité de SherbrookeSherbrookeQuébecCanada
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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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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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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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Bazard P, Frisina RD, Acosta AA, Dasgupta S, Bauer MA, Zhu X, Ding B. Roles of Key Ion Channels and Transport Proteins in Age-Related Hearing Loss. Int J Mol Sci 2021; 22:6158. [PMID: 34200434 PMCID: PMC8201059 DOI: 10.3390/ijms22116158] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/30/2021] [Accepted: 05/31/2021] [Indexed: 12/25/2022] Open
Abstract
The auditory system is a fascinating sensory organ that overall, converts sound signals to electrical signals of the nervous system. Initially, sound energy is converted to mechanical energy via amplification processes in the middle ear, followed by transduction of mechanical movements of the oval window into electrochemical signals in the cochlear hair cells, and finally, neural signals travel to the central auditory system, via the auditory division of the 8th cranial nerve. The majority of people above 60 years have some form of age-related hearing loss, also known as presbycusis. However, the biological mechanisms of presbycusis are complex and not yet fully delineated. In the present article, we highlight ion channels and transport proteins, which are integral for the proper functioning of the auditory system, facilitating the diffusion of various ions across auditory structures for signal transduction and processing. Like most other physiological systems, hearing abilities decline with age, hence, it is imperative to fully understand inner ear aging changes, so ion channel functions should be further investigated in the aging cochlea. In this review article, we discuss key various ion channels in the auditory system and how their functions change with age. Understanding the roles of ion channels in auditory processing could enhance the development of potential biotherapies for age-related hearing loss.
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Affiliation(s)
- Parveen Bazard
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Robert D. Frisina
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
- Department Communication Sciences and Disorders, College of Behavioral & Communication Sciences, Tampa, FL 33620, USA
| | - Alejandro A. Acosta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Sneha Dasgupta
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Mark A. Bauer
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Xiaoxia Zhu
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
| | - Bo Ding
- Department of Medical Engineering, College of Engineering, University of South Florida, Tampa, FL 33620, USA; (P.B.); (A.A.A.); (S.D.); (M.A.B.); (X.Z.); (B.D.)
- Global Center for Hearing and Speech Research, University of South Florida, Tampa, FL 33612, USA
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49
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Numata T, Sato-Numata K, Yoshino M. BK Channels Are Activated by Functional Coupling With L-Type Ca 2+ Channels in Cricket Myocytes. FRONTIERS IN INSECT SCIENCE 2021; 1:662414. [PMID: 38468898 PMCID: PMC10926482 DOI: 10.3389/finsc.2021.662414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/15/2021] [Indexed: 03/13/2024]
Abstract
Large-conductance calcium (Ca2+)-activated potassium (K+) (BK) channel activation is important for feedback control of Ca2+ influx and cell excitability during spontaneous muscle contraction. To characterize endogenously expressed BK channels and evaluate the functional relevance of Ca2+ sources leading to BK activity, patch-clamp electrophysiology was performed on cricket oviduct myocytes to obtain single-channel recordings. The single-channel conductance of BK channels was 120 pS, with increased activity resulting from membrane depolarization or increased intracellular Ca2+ concentration. Extracellular application of tetraethylammonium (TEA) and iberiotoxin (IbTX) suppressed single-channel current amplitude. These results indicate that BK channels are endogenously expressed in cricket oviduct myocytes. Ca2+ release from internal Ca2+ stores and Ca2+ influx via the plasma membrane, which affect BK activity, were investigated. Extracellular Ca2+ removal nullified BK activity. Administration of ryanodine and caffeine reduced BK activity. Administration of L-type Ca2+ channel activity regulators (Bay K 8644 and nifedipine) increased and decreased BK activity, respectively. Finally, the proximity between the L-type Ca2+ channel and BK was investigated. Administration of Bay K 8644 to the microscopic area within the pipette increased BK activity. However, this increase was not observed at a sustained depolarizing potential. These results show that BK channels are endogenously expressed in cricket oviduct myocytes and that BK activity is regulated by L-type Ca2+ channel activity and Ca2+ release from Ca2+ stores. Together, these results show that functional coupling between L-type Ca2+ and BK channels may underlie the molecular basis of spontaneous rhythmic contraction.
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Affiliation(s)
- Tomohiro Numata
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
| | - Kaori Sato-Numata
- Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Masami Yoshino
- Department of Biology, Tokyo Gakugei University, Tokyo, Japan
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50
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Gezalian MM, Mangiacotti L, Rajput P, Sparrow N, Schlick K, Lahiri S. Cerebrovascular and neurological perspectives on adrenoceptor and calcium channel modulating pharmacotherapies. J Cereb Blood Flow Metab 2021; 41:693-706. [PMID: 33210576 PMCID: PMC7983505 DOI: 10.1177/0271678x20972869] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/12/2020] [Accepted: 10/13/2020] [Indexed: 02/02/2023]
Abstract
Adrenoceptor and calcium channel modulating medications are widely used in clinical practice for acute neurological and systemic conditions. It is generally assumed that the cerebrovascular effects of these drugs mirror that of their systemic effects - and this is reflected in how these medications are currently used in clinical practice. However, recent research suggests that there are distinct cerebrovascular-specific effects of these medications that are related to the unique characteristics of the cerebrovascular anatomy including the regional heterogeneity in density and distribution of adrenoceptor subtypes and calcium channels along the cerebrovasculature. In this review, we critically evaluate existing basic science and clinical research to discuss known and putative interactions between adrenoceptor and calcium channel modulating pharmacotherapies, the neurovascular unit, and cerebrovascular anatomy. In doing so, we provide a rationale for selecting vasoactive medications based on lesion location and lay a foundation for future investigations that will define neuroprotective paradigms of adrenoceptor and calcium channel modulating therapies to improve neurological outcomes in acute neurological and systemic disorders.
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Affiliation(s)
- Michael M Gezalian
- Departments of Neurology and Neurosurgery, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Luigi Mangiacotti
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Padmesh Rajput
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Nicklaus Sparrow
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Konrad Schlick
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Shouri Lahiri
- Departments of Neurology, Neurosurgery, and Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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