1
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Lauerer RJ, Lerche H. Voltage-gated calcium channels in genetic epilepsies. J Neurochem 2023. [PMID: 37822150 DOI: 10.1111/jnc.15983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Revised: 09/17/2023] [Accepted: 09/25/2023] [Indexed: 10/13/2023]
Abstract
Voltage-gated calcium channels (VGCC) are abundant in the central nervous system and serve a broad spectrum of functions, either directly in cellular excitability or indirectly to regulate Ca2+ homeostasis. Ca2+ ions act as one of the main connections in excitation-transcription coupling, muscle contraction and excitation-exocytosis coupling, including synaptic transmission. In recent years, many genes encoding VGCCs main α or additional auxiliary subunits have been associated with epilepsy. This review sums up the current state of knowledge on disease mechanisms and provides guidance on disease-specific therapies where applicable.
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Affiliation(s)
- Robert J Lauerer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University and University Hospital Tuebingen, Tuebingen, Germany
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2
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Matthews LG, Puryear CB, Correia SS, Srinivasan S, Belfort GM, Pan MK, Kuo SH. T-type calcium channels as therapeutic targets in essential tremor and Parkinson's disease. Ann Clin Transl Neurol 2023; 10:462-483. [PMID: 36738196 PMCID: PMC10109288 DOI: 10.1002/acn3.51735] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 02/05/2023] Open
Abstract
Neuronal action potential firing patterns are key components of healthy brain function. Importantly, restoring dysregulated neuronal firing patterns has the potential to be a promising strategy in the development of novel therapeutics for disorders of the central nervous system. Here, we review the pathophysiology of essential tremor and Parkinson's disease, the two most common movement disorders, with a focus on mechanisms underlying the genesis of abnormal firing patterns in the implicated neural circuits. Aberrant burst firing of neurons in the cerebello-thalamo-cortical and basal ganglia-thalamo-cortical circuits contribute to the clinical symptoms of essential tremor and Parkinson's disease, respectively, and T-type calcium channels play a key role in regulating this activity in both the disorders. Accordingly, modulating T-type calcium channel activity has received attention as a potentially promising therapeutic approach to normalize abnormal burst firing in these diseases. In this review, we explore the evidence supporting the theory that T-type calcium channel blockers can ameliorate the pathophysiologic mechanisms underlying essential tremor and Parkinson's disease, furthering the case for clinical investigation of these compounds. We conclude with key considerations for future investigational efforts, providing a critical framework for the development of much needed agents capable of targeting the dysfunctional circuitry underlying movement disorders such as essential tremor, Parkinson's disease, and beyond.
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Affiliation(s)
| | - Corey B Puryear
- Praxis Precision Medicines, Boston, Massachusetts, 02110, USA
| | | | - Sharan Srinivasan
- Praxis Precision Medicines, Boston, Massachusetts, 02110, USA.,Department of Neurology, University of Michigan, Ann Arbor, Michigan, 48109, USA
| | | | - Ming-Kai Pan
- Department and Graduate Institute of Pharmacology, National Taiwan University College of Medicine, Taipei, 10051, Taiwan.,Neurobiology and Cognitive Science Center, National Taiwan University, Taipei, 10617, Taiwan.,Department of Medical Research, National Taiwan University Hospital, Taipei, 10002, Taiwan.,Cerebellar Research Center, National Taiwan University Hospital, Yun-Lin Branch, Yun-Lin, 64041, Taiwan
| | - Sheng-Han Kuo
- Department of Neurology, Columbia University, New York, New York, 10032, USA.,Initiative for Columbia Ataxia and Tremor, Columbia University, New York, New York, 10032, USA
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3
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Xing C, Bao L, Li W, Fan H. Progress on role of ion channels of cardiac fibroblasts in fibrosis. Front Physiol 2023; 14:1138306. [PMID: 36969589 PMCID: PMC10033868 DOI: 10.3389/fphys.2023.1138306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 02/27/2023] [Indexed: 03/29/2023] Open
Abstract
Cardiac fibrosis is defined as excessive deposition of extracellular matrix (ECM) in pathological conditions. Cardiac fibroblasts (CFs) activated by injury or inflammation differentiate into myofibroblasts (MFs) with secretory and contractile functions. In the fibrotic heart, MFs produce ECM which is composed mainly of collagen and is initially involved in maintaining tissue integrity. However, persistent fibrosis disrupts the coordination of excitatory contractile coupling, leading to systolic and diastolic dysfunction, and ultimately heart failure. Numerous studies have demonstrated that both voltage- and non-voltage-gated ion channels alter intracellular ion levels and cellular activity, contributing to myofibroblast proliferation, contraction, and secretory function. However, an effective treatment strategy for myocardial fibrosis has not been established. Therefore, this review describes the progress made in research related to transient receptor potential (TRP) channels, Piezo1, Ca2+ release-activated Ca2+ (CRAC) channels, voltage-gated Ca2+ channels (VGCCs), sodium channels, and potassium channels in myocardial fibroblasts with the aim of providing new ideas for treating myocardial fibrosis.
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4
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El Ghaleb Y, Flucher BE. Ca V3.3 Channelopathies. Handb Exp Pharmacol 2023; 279:263-288. [PMID: 36592228 DOI: 10.1007/164_2022_631] [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: 01/03/2023]
Abstract
CaV3.3 is the third member of the low-voltage-activated calcium channel family and the last to be recognized as disease gene. Previously, CACNA1I, the gene encoding CaV3.3, had been described as schizophrenia risk gene. More recently, de novo missense mutations in CACNA1I were identified in patients with variable degrees of neurodevelopmental disease with and without epilepsy. Their functional characterization indicated gain-of-function effects resulting in increased calcium load and hyperexcitability of neurons expressing CaV3.3. The amino acids mutated in the CaV3.3 disease variants are located in the vicinity of the channel's activation gate and thus are classified as gate-modifying channelopathy mutations. A persistent calcium leak during rest and prolonged calcium spikes due to increased voltage sensitivity of activation and slowed kinetics of channel inactivation, respectively, may be causal for the neurodevelopmental defects. The prominent expression of CaV3.3 in thalamic reticular nucleus neurons and its essential role in generating the rhythmic thalamocortical network activity are consistent with a role of the mutated channels in the etiology of epileptic seizures and thus suggest T-type channel blockers as a viable treatment option.
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Affiliation(s)
- Yousra El Ghaleb
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, Innsbruck, Austria.
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Mustafá ER, McCarthy CI, Portales AE, Cordisco Gonzalez S, Rodríguez SS, Raingo J. Constitutive activity of the dopamine (D 5 ) receptor, highly expressed in CA1 hippocampal neurons, selectively reduces Ca V 3.2 and Ca V 3.3 currents. Br J Pharmacol 2022; 180:1210-1231. [PMID: 36480023 DOI: 10.1111/bph.16006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 10/31/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND AND PURPOSE CaV 3.1-3 currents differentially contribute to neuronal firing patterns. CaV 3 are regulated by G protein-coupled receptors (GPCRs) activity, but information about CaV 3 as targets of the constitutive activity of GPCRs is scarce. We investigate the impact of D5 recpetor constitutive activity, a GPCR with high levels of basal activity, on CaV 3 functionality. D5 recpetor and CaV 3 are expressed in the hippocampus and have been independently linked to pathophysiological states associated with epilepsy. EXPERIMENTAL APPROACH Our study models were HEK293T cells heterologously expressing D1 or D5 receptor and CaV 3.1-3, and mouse brain slices containing the hippocampus. We used chlorpromazine (D1 /D5 inverse agonist) and a D5 receptor mutant lacking constitutive activity as experimental tools. We measured CaV 3 currents and excitability parameters using the patch-clamp technique. We completed our study with computational modelling and imaging technique. KEY RESULTS We found a higher sensitivity to TTA-P2 (CaV 3 blocker) in CA1 pyramidal neurons obtained from chlorpromazine-treated animals compared with vehicle-treated animals. We found that CaV 3.2 and CaV 3.3-but not CaV 3.1-are targets of D5 receptor constitutive activity in HEK293T cells. Finally, we found an increased firing rate in CA1 pyramidal neurons from chlorpromazine-treated animals in comparison with vehicle-treated animals. Similar changes in firing rate were observed on a neuronal model with controlled CaV 3 currents levels. CONCLUSIONS AND IMPLICATIONS Native hippocampal CaV 3 and recombinant CaV 3.2-3 are sensitive to D5 receptor constitutive activity. Manipulation of D5 receptor constitutive activity could be a valuable strategy to control neuronal excitability, especially in exacerbated conditions such as epilepsy.
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Affiliation(s)
- Emilio Román Mustafá
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Clara Inés McCarthy
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Andrea Estefanía Portales
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Santiago Cordisco Gonzalez
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Silvia Susana Rodríguez
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
| | - Jesica Raingo
- Electrophysiology Laboratory of the Multidisciplinary Institute of Cell Biology [Argentine Research Council (CONICET), Scientific Research Commission of the Province of Buenos Aires (CIC-PBA) and National University of La Plata (UNLP)], Buenos Aires, Argentina
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6
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Eickhoff A, Tjaden J, Stahlke S, Vorgerd M, Theis V, Matschke V, Theiss C. Effects of progesterone on T-type-Ca 2+-channel expression in Purkinje cells. Neural Regen Res 2022; 17:2465-2471. [PMID: 35535898 PMCID: PMC9120685 DOI: 10.4103/1673-5374.339008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Plasticity of cerebellar Purkinje cells (PC) is influenced by progesterone via the classical progesterone receptors PR-A and PR-B by stimulating dendritogenesis, spinogenesis, and synaptogenesis in these cells. Dissociated PC cultures were used to analyze progesterone effects at a molecular level on the voltage-gated T-type-Ca2+-channels Cav3.1, Cav3.2, and Cav3.3 as they helped determine neuronal plasticity by regulating Ca2+-influx in neuronal cells. The results showed direct effects of progesterone on the mRNA expression of T-type-Ca2+-channels, as well as on the protein kinases A and C being involved in downstream signaling pathways that play an important role in neuronal plasticity. For the mRNA expression studies of T-type-Ca2+-channels and protein kinases of the signaling cascade, laser microdissection and purified PC cultures of different maturation stages were used. Immunohistochemical staining was also performed to characterize the localization of T-type-Ca2+-channels in PC. Experimental progesterone treatment was performed on the purified PC culture for 24 and 48 hours. Our results show that progesterone increases the expression of Cav3.1 and Cav3.3 and associated protein kinases A and C in PC at the mRNA level within 48 hours after treatment at latest. These effects extend the current knowledge of the function of progesterone in the central nervous system and provide an explanatory approach for its influence on neuronal plasticity.
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Affiliation(s)
- Annika Eickhoff
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Jonas Tjaden
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Sarah Stahlke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Matthias Vorgerd
- Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-Universität Bochum, Bochum, Germany
| | - Verena Theis
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Veronika Matschke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Bochum, Germany
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7
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T-Type Calcium Channels: A Mixed Blessing. Int J Mol Sci 2022; 23:ijms23179894. [PMID: 36077291 PMCID: PMC9456242 DOI: 10.3390/ijms23179894] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/17/2022] Open
Abstract
The role of T-type calcium channels is well established in excitable cells, where they preside over action potential generation, automaticity, and firing. They also contribute to intracellular calcium signaling, cell cycle progression, and cell fate; and, in this sense, they emerge as key regulators also in non-excitable cells. In particular, their expression may be considered a prognostic factor in cancer. Almost all cancer cells express T-type calcium channels to the point that it has been considered a pharmacological target; but, as the drugs used to reduce their expression are not completely selective, several complications develop, especially within the heart. T-type calcium channels are also involved in a specific side effect of several anticancer agents, that act on microtubule transport, increase the expression of the channel, and, thus, the excitability of sensory neurons, and make the patient more sensitive to pain. This review puts into context the relevance of T-type calcium channels in cancer and in chemotherapy side effects, considering also the cardiotoxicity induced by new classes of antineoplastic molecules.
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8
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Mirlohi S, Bladen C, Santiago M, Connor M. Modulation of Recombinant Human T-Type Calcium Channels by Δ 9-Tetrahydrocannabinolic Acid In Vitro. Cannabis Cannabinoid Res 2022; 7:34-45. [PMID: 33998881 PMCID: PMC8864432 DOI: 10.1089/can.2020.0134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Introduction: Low voltage-activated T-type calcium channels (T-type ICa), CaV3.1, CaV3.2, and CaV3.3, are opened by small depolarizations from the resting membrane potential in many cells and have been associated with neurological disorders, including absence epilepsy and pain. Δ9-tetrahydrocannabinol (THC) is the principal psychoactive compound in Cannabis and also directly modulates T-type ICa; however, there is no information about functional activity of most phytocannabinoids on T-type calcium channels, including Δ9-tetrahydrocannabinolic acid (THCA), the natural nonpsychoactive precursor of THC. The aim of this work was to characterize THCA effects on T-type calcium channels. Materials and Methods: We used HEK293 Flp-In-TREx cells stably expressing CaV3.1, 3.2, or 3.3. Whole-cell patch clamp recordings were made to investigate cannabinoid modulation of ICa. Results: THCA and THC inhibited the peak current amplitude CaV3.1 with pEC50s of 6.0±0.7 and 5.6±0.4, respectively. THC (1 μM) or THC produced a significant negative shift in half activation and inactivation of CaV3.1, and both drugs prolonged CaV3.1 deactivation kinetics. THCA (10 μM) inhibited CaV3.2 by 53%±4%, and both THCA and THC produced a substantial negative shift in the voltage for half inactivation and modest negative shift in half activation of CaV3.2. THC prolonged the deactivation time of CaV3.2, while THCA did not. THCA inhibited the peak current of CaV3.3 by 43%±2% (10 μM) but did not notably affect CaV3.3 channel activation or inactivation; however, THC caused significant hyperpolarizing shift in CaV3.3 steady-state inactivation. Discussion: THCA modulated T-type ICa currents in vitro, with significant modulation of kinetics and voltage dependence at low μM concentrations. This study suggests that THCA may have potential for therapeutic use in pain and epilepsy through T-type calcium channel modulation without the unwanted psychoactive effects associated with THC.
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Affiliation(s)
- Somayeh Mirlohi
- Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Chris Bladen
- Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Marina Santiago
- Department of Biomedical Sciences, Macquarie University, Sydney, Australia
| | - Mark Connor
- Department of Biomedical Sciences, Macquarie University, Sydney, Australia.,*Address correspondence to: Mark Connor, PhD, Department of Biomedical Sciences, Macquarie University, Sydney 2109, Australia,
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9
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Maksemous N, Blayney CD, Sutherland HG, Smith RA, Lea RA, Tran KN, Ibrahim O, McArthur JR, Haupt LM, Cader MZ, Finol-Urdaneta RK, Adams DJ, Griffiths LR. Investigation of CACNA1I Cav3.3 Dysfunction in Hemiplegic Migraine. Front Mol Neurosci 2022; 15:892820. [PMID: 35928792 PMCID: PMC9345121 DOI: 10.3389/fnmol.2022.892820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 06/13/2022] [Indexed: 01/12/2023] Open
Abstract
Familial hemiplegic migraine (FHM) is a severe neurogenetic disorder for which three causal genes, CACNA1A, SCN1A, and ATP1A2, have been implicated. However, more than 80% of referred diagnostic cases of hemiplegic migraine (HM) are negative for exonic mutations in these known FHM genes, suggesting the involvement of other genes. Using whole-exome sequencing data from 187 mutation-negative HM cases, we identified rare variants in the CACNA1I gene encoding the T-type calcium channel Cav3.3. Burden testing of CACNA1I variants showed a statistically significant increase in allelic burden in the HM case group compared to gnomAD (OR = 2.30, P = 0.00005) and the UK Biobank (OR = 2.32, P = 0.0004) databases. Dysfunction in T-type calcium channels, including Cav3.3, has been implicated in a range of neurological conditions, suggesting a potential role in HM. Using patch-clamp electrophysiology, we compared the biophysical properties of five Cav3.3 variants (p.R111G, p.M128L, p.D302G, p.R307H, and p.Q1158H) to wild-type (WT) channels expressed in HEK293T cells. We observed numerous functional alterations across the channels with Cav3.3-Q1158H showing the greatest differences compared to WT channels, including reduced current density, right-shifted voltage dependence of activation and inactivation, and slower current kinetics. Interestingly, we also found significant differences in the conductance properties exhibited by the Cav3.3-R307H and -Q1158H variants compared to WT channels under conditions of acidosis and alkalosis. In light of these data, we suggest that rare variants in CACNA1I may contribute to HM etiology.
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Affiliation(s)
- Neven Maksemous
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Claire D Blayney
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Heidi G Sutherland
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Robert A Smith
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Rod A Lea
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Kim Ngan Tran
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Omar Ibrahim
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - Jeffrey R McArthur
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Larisa M Haupt
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
| | - M Zameel Cader
- Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Rocio K Finol-Urdaneta
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - David J Adams
- Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia
| | - Lyn R Griffiths
- Genomics Research Centre, The Centre for Genomics and Personalised Health, School of Biomedical Sciences, Queensland University of Technology, Brisbane, QLD, Australia
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10
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Tjaden J, Eickhoff A, Stahlke S, Gehmeyr J, Vorgerd M, Theis V, Matschke V, Theiss C. Expression Pattern of T-Type Ca 2+ Channels in Cerebellar Purkinje Cells after VEGF Treatment. Cells 2021; 10:2277. [PMID: 34571926 PMCID: PMC8470219 DOI: 10.3390/cells10092277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/27/2021] [Accepted: 08/28/2021] [Indexed: 12/04/2022] Open
Abstract
T-type Ca2+ channels, generating low threshold calcium influx in neurons, play a crucial role in the function of neuronal networks and their plasticity. To further investigate their role in the complex field of research in plasticity of neurons on a molecular level, this study aimed to analyse the impact of the vascular endothelial growth factor (VEGF) on these channels. VEGF, known as a player in vasculogenesis, also shows potent influence in the central nervous system, where it elicits neuronal growth. To investigate the influence of VEGF on the three T-type Ca2+ channel isoforms, Cav3.1 (encoded by Cacna1g), Cav3.2 (encoded by Cacna1h), and Cav3.3 (encoded by Cacna1i), lasermicrodissection of in vivo-grown Purkinje cells (PCs) was performed, gene expression was analysed via qPCR and compared to in vitro-grown PCs. We investigated the VEGF receptor composition of in vivo- and in vitro-grown PCs and underlined the importance of VEGF receptor 2 for PCs. Furthermore, we performed immunostaining of T-type Ca2+ channels with in vivo- and in vitro-grown PCs and showed the distribution of T-type Ca2+ channel expression during PC development. Overall, our findings provide the first evidence that the mRNA expression of Cav3.1, Cav3.2, and Cav3.3 increases due to VEGF stimulation, which indicates an impact of VEGF on neuronal plasticity.
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Affiliation(s)
- Jonas Tjaden
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Annika Eickhoff
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Sarah Stahlke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Julian Gehmeyr
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Matthias Vorgerd
- Department of Neurology, Neuromuscular Center Ruhrgebiet, University Hospital Bergmannsheil, Ruhr-University Bochum, Buerkle-de-la-Camp-Platz 1, 44789 Bochum, Germany;
| | - Verena Theis
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Veronika Matschke
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
| | - Carsten Theiss
- Department of Cytology, Institute of Anatomy, Ruhr-University Bochum, Universitätsstr. 150, 44801 Bochum, Germany; (J.T.); (A.E.); (S.S.); (J.G.); (V.T.); (V.M.)
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11
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Targeting T-type/CaV3.2 channels for chronic pain. Transl Res 2021; 234:20-30. [PMID: 33422652 PMCID: PMC8217081 DOI: 10.1016/j.trsl.2021.01.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 01/09/2023]
Abstract
T-type calcium channels regulate neuronal excitability and are important contributors of pain processing. CaV3.2 channels are the major isoform expressed in nonpeptidergic and peptidergic nociceptive neurons and are emerging as promising targets for pain treatment. Numerous studies have shown that CaV3.2 expression and/or activity are significantly increased in spinal dorsal horn and in dorsal root ganglia neurons in different inflammatory and neuropathic pain models. Pharmacological campaigns to inhibit the functional expression of CaV3.2 for treatment of pain have focused on the development of direct channel blockers, but none have produced lead candidates. Targeting the proteins that regulate the trafficking or transcription, and the ones that modify the channels via post-translational modifications are alternative means to regulate expression and function of CaV3.2 channels and hence to develop new drugs to control pain. Here we synthesize data supporting a role for CaV3.2 in numerous pain modalities and then discuss emerging opportunities for the indirect targeting of CaV3.2 channels.
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12
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Stroedecke K, Meinel S, Markwardt F, Kloeckner U, Straetz N, Quarch K, Schreier B, Kopf M, Gekle M, Grossmann C. The mineralocorticoid receptor leads to increased expression of EGFR and T-type calcium channels that support HL-1 cell hypertrophy. Sci Rep 2021; 11:13229. [PMID: 34168192 PMCID: PMC8225817 DOI: 10.1038/s41598-021-92284-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 05/05/2021] [Indexed: 11/12/2022] Open
Abstract
The EGF receptor (EGFR) has been extensively studied in tumor biology and recently a role in cardiovascular pathophysiology was suggested. The mineralocorticoid receptor (MR) is an important effector of the renin-angiotensin-aldosterone-system and elicits pathophysiological effects in the cardiovascular system; however, the underlying molecular mechanisms are unclear. Our aim was to investigate the importance of EGFR for MR-mediated cardiovascular pathophysiology because MR is known to induce EGFR expression. We identified a SNP within the EGFR promoter that modulates MR-induced EGFR expression. In RNA-sequencing and qPCR experiments in heart tissue of EGFR KO and WT mice, changes in EGFR abundance led to differential expression of cardiac ion channels, especially of the T-type calcium channel CACNA1H. Accordingly, CACNA1H expression was increased in WT mice after in vivo MR activation by aldosterone but not in respective EGFR KO mice. Aldosterone- and EGF-responsiveness of CACNA1H expression was confirmed in HL-1 cells by Western blot and by measuring peak current density of T-type calcium channels. Aldosterone-induced CACNA1H protein expression could be abrogated by the EGFR inhibitor AG1478. Furthermore, inhibition of T-type calcium channels with mibefradil or ML218 reduced diameter, volume and BNP levels in HL-1 cells. In conclusion the MR regulates EGFR and CACNA1H expression, which has an effect on HL-1 cell diameter, and the extent of this regulation seems to depend on the SNP-216 (G/T) genotype. This suggests that the EGFR may be an intermediate for MR-mediated cardiovascular changes and that SNP analysis can help identify subgroups of patients that will benefit most from MR antagonists.
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Affiliation(s)
- Katharina Stroedecke
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Sandra Meinel
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Fritz Markwardt
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Udo Kloeckner
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Nicole Straetz
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Katja Quarch
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Barbara Schreier
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Michael Kopf
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Michael Gekle
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany
| | - Claudia Grossmann
- Julius Bernstein Institute of Physiology, Martin Luther University Halle-Wittenberg, Magdeburger Str. 6, 06097, Halle, Saale, Germany.
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13
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Jacquerie K, Drion G. Robust switches in thalamic network activity require a timescale separation between sodium and T-type calcium channel activations. PLoS Comput Biol 2021; 17:e1008997. [PMID: 34003841 PMCID: PMC8162675 DOI: 10.1371/journal.pcbi.1008997] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 05/28/2021] [Accepted: 04/23/2021] [Indexed: 11/18/2022] Open
Abstract
Switches in brain states, synaptic plasticity and neuromodulation are fundamental processes in our brain that take place concomitantly across several spatial and timescales. All these processes target neuron intrinsic properties and connectivity to achieve specific physiological goals, raising the question of how they can operate without interfering with each other. Here, we highlight the central importance of a timescale separation in the activation of sodium and T-type calcium channels to sustain robust switches in brain states in thalamic neurons that are compatible with synaptic plasticity and neuromodulation. We quantify the role of this timescale separation by comparing the robustness of rhythms of six published conductance-based models at the cellular, circuit and network levels. We show that robust rhythm generation requires a T-type calcium channel activation whose kinetics are situated between sodium channel activation and T-type calcium channel inactivation in all models despite their quantitative differences. Our brain is constantly processing information either from the environment to quickly react to incoming events or learning from experience to shape our memory. These brain states translate a collective activity of neurons interconnected via synaptic connections. Here, we focus on the thalamic network showing a transition from an active to an oscillatory mode at the population level, reverberating a switch from tonic to bursting mode at the cellular level. We are questioning how these activity fluctuations can be robustly modeled despite synaptic plasticity affecting the network configuration and the presence of neuromodulators affecting neuron intrinsic properties. To do so, we investigate six conductance-based models and their ability to reproduce activity switches at the cellular, circuit and population levels. We highlight that the robustness requires the timescale separation between the fast activation of sodium channels compared to the slow activation of T-type calcium channels. Our results show that this kinetics difference is not a computational detail but rather makes a model suitable and robust to study the interaction between switches in brain states, synaptic plasticity and neuromodulation.
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Affiliation(s)
- Kathleen Jacquerie
- Department of Electrical Engineering and Computer Science, University of Liege, Liege, Belgium
- * E-mail:
| | - Guillaume Drion
- Department of Electrical Engineering and Computer Science, University of Liege, Liege, Belgium
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14
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Lee JY, Zheng H, Sanders KM, Koh SD. Low-voltage-activated inward current in murine antral smooth muscle cells is an artifact. Am J Physiol Cell Physiol 2021; 320:C966-C973. [PMID: 33788632 DOI: 10.1152/ajpcell.00031.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Two types of voltage-dependent inward currents were evoked by depolarization in murine antral smooth muscle cells (SMCs) bathed in Ca2+-containing physiological solution: high-voltage-activated (HVA) and low-voltage-activated (LVA) inward currents. We examined whether the LVA current was due to: 1) T-type Ca2+ channels, 2) Ca2+-activated Cl-channels, 3) nonselective cation channels (NSCC), or 4) voltage-dependent K+ channels. Replacement of external Ca2+ (2 mM) with equimolar Ba2+ increased the amplitude of the HVA current but blocked the LVA current. Nicardipine blocked the HVA current, and in the presence of nicardipine, T-type Ca2+ blockers failed to block LVA current. A Cl- channel antagonist had little effect on LVA current. Cation-free external solution completely abolished both HVA and LVA currents. Addition of Ca2+ to the solution restored only HVA currents. Addition of K+ (5 mM) to otherwise cation-free solution induced LVA current that reversed at -20 mV. These data suggest that LVA current is not due to T-type Ca2+ channels, Ca2+-activated Cl- channels, or NSCC. A-type K+ (KA) currents and delayed rectifying K+ (KDR) currents can be resolved in antral SMCs dialyzed with a solution containing 140 mM K+. When cells were exposed to high K+ external solution and dialyzed with Cs+-rich solution in the presence of nicardipine, LVA current was evoked and reversed at positive potentials. LVA currents were blocked by K+ channel blockers, 4-aminopyridine, and tetraethylammonium. In conclusion, LVA inward currents can be generated by K+ influx via KA channels in murine antral SMCs when cells were dialyzed with Cs+-rich solution.
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Affiliation(s)
- Ji Yeon Lee
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Haifeng Zheng
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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15
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Barrett PQ, Guagliardo NA, Bayliss DA. Ion Channel Function and Electrical Excitability in the Zona Glomerulosa: A Network Perspective on Aldosterone Regulation. Annu Rev Physiol 2020; 83:451-475. [PMID: 33176563 DOI: 10.1146/annurev-physiol-030220-113038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Aldosterone excess is a pathogenic factor in many hypertensive disorders. The discovery of numerous somatic and germline mutations in ion channels in primary hyperaldosteronism underscores the importance of plasma membrane conductances in determining the activation state of zona glomerulosa (zG) cells. Electrophysiological recordings describe an electrically quiescent behavior for dispersed zG cells. Yet, emerging data indicate that in native rosette structures in situ, zG cells are electrically excitable, generating slow periodic voltage spikes and coordinated bursts of Ca2+ oscillations. We revisit data to understand how a multitude of conductances may underlie voltage/Ca2+ oscillations, recognizing that zG layer self-renewal and cell heterogeneity may complicate this task. We review recent data to understand rosette architecture and apply maxims derived from computational network modeling to understand rosette function. The challenge going forward is to uncover how the rosette orchestrates the behavior of a functional network of conditional oscillators to control zG layer performance and aldosterone secretion.
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Affiliation(s)
- Paula Q Barrett
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
| | - Nick A Guagliardo
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, Virginia 22908, USA; , ,
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16
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Dolphin AC. Functions of Presynaptic Voltage-gated Calcium Channels. FUNCTION (OXFORD, ENGLAND) 2020; 2:zqaa027. [PMID: 33313507 PMCID: PMC7709543 DOI: 10.1093/function/zqaa027] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 10/16/2020] [Accepted: 10/20/2020] [Indexed: 01/06/2023]
Abstract
Voltage-gated calcium channels are the principal conduits for depolarization-mediated Ca2+ entry into excitable cells. In this review, the biophysical properties of the relevant members of this family of channels, those that are present in presynaptic terminals, will be discussed in relation to their function in mediating neurotransmitter release. Voltage-gated calcium channels have properties that ensure they are specialized for particular roles, for example, differences in their activation voltage threshold, their various kinetic properties, and their voltage-dependence of inactivation. All these attributes play into the ability of the various voltage-gated calcium channels to participate in different patterns of presynaptic vesicular release. These include synaptic transmission resulting from single action potentials, and longer-term changes mediated by bursts or trains of action potentials, as well as release resulting from graded changes in membrane potential in specialized sensory synapses.
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Affiliation(s)
- Annette C Dolphin
- Department of Neuroscience, Physiology and Pharmacology, University College London, WC1E 6BT, UK,Address correspondence to A.C.D. (e-mail: )
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17
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Guidelli R, Becucci L. Deterministic model of Ca v3.1 Ca 2+ channel and a proposed sequence of its conformations. Bioelectrochemistry 2020; 136:107618. [PMID: 32795940 DOI: 10.1016/j.bioelechem.2020.107618] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Revised: 06/29/2020] [Accepted: 07/21/2020] [Indexed: 10/23/2022]
Abstract
A family of current-time curves of T-type Cav3.1 Ca2+ channels available in the literature is simulated by a kinetic model differing from that used for the interpretation of all salient features of Na+ and Shaker K+ channels by the insertion of a multiplying factor expressing the difference between the working potential ϕ and the reversal potential ϕr. This deterministic model is also used to simulate experimental curves taken from the literature for steady-state 'fast inactivation' and for a gradual passage from fast to 'slow inactivation'. A depolarizing pulse induces fast or slow inactivation depending on whether it lasts 100-500 ms or about 1 min, and is believed to cause a collapse of the central pore near the selectivity filter (SF). A number of features of fast and slow inactivation of Cav3.1 Ca2+ channels are qualitatively interpreted on the basis of a sequence of conformational states. Briefly, the conformation responsible for 'fast inactivation' is assumed to have the activation gate open and the inactivation gate (i.e., the SF) inactive. Immediately after a depolarizing pulse, this conformation is inactive and requires a sufficiently long rest time at a far negative holding potential to recover from inactivation. 'Slow inactivation' is ascribed to a different conformation with the activation gate closed and the SF inactive.
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Affiliation(s)
- Rolando Guidelli
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy.
| | - Lucia Becucci
- Department of Chemistry "Ugo Schiff", Florence University, Via della Lastruccia 3, 50019 Sesto Fiorentino (Firenze), Italy
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18
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Modulation of Voltage-Gated Sodium Channel Activity in Human Dorsal Root Ganglion Neurons by Herpesvirus Quiescent Infection. J Virol 2020; 94:JVI.01823-19. [PMID: 31694955 DOI: 10.1128/jvi.01823-19] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 10/25/2019] [Indexed: 12/15/2022] Open
Abstract
The molecular mechanisms of pain associated with alphaherpesvirus latency are not clear. We hypothesize that the voltage-gated sodium channels (VGSC) on the dorsal root ganglion (DRG) neurons controlling electrical impulses may have abnormal activity during latent viral infection and reactivation. We used herpes simplex virus 1 (HSV-1) to infect the human DRG-derived neuronal cell line HD10.6 in order to study the establishment and maintenance of viral latency, viral reactivation, and changes in the functional expression of VGSCs. Differentiated cells exhibited robust tetrodotoxin (TTX)-sensitive sodium currents, and acute infection significantly reduced the functional expression of VGSCs within 24 h and completely abolished VGSC activity within 3 days. A quiescent state of infection mimicking latency can be achieved in the presence of acyclovir (ACV) for 7 days followed by 5 days of ACV washout, and then the viruses can remain dormant for another 3 weeks. It was noted that during the establishment of HSV-1 latency, the loss of VGSC activity caused by HSV-1 infection could not be blocked by ACV treatment. However, neurons with continued ACV treatment for another 4 days showed a gradual recovery of VGSC functional expression. Furthermore, the latently infected neurons exhibited higher VGSC activity than controls. The overall regulation of VGSCs by HSV-1 during quiescent infection was proved by increased transcription and possible translation of Nav1.7. Together, these observations demonstrated a very complex pattern of electrophysiological changes during HSV infection of DRG neurons, which may have implications for understanding of the mechanisms of virus-mediated pain linked to latency and reactivation.IMPORTANCE The reactivation of herpesviruses, most commonly varicella-zoster virus (VZV) and pseudorabies virus (PRV), may cause cranial nerve disorder and unbearable pain. Clinical studies have also reported that HSV-1 causes postherpetic neuralgia and chronic occipital neuralgia in humans. The current work meticulously studies the functional expression profile changes of VGSCs during the processes of HSV-1 latency establishment and reactivation using human dorsal root ganglion-derived neuronal HD10.6 cells as an in vitro model. Our results indicated that VGSC activity was eliminated upon infection but steadily recovered during latency establishment and that latent neurons exhibited even higher VGSC activity. This finding advances our knowledge of how ganglion neurons generate uncharacteristic electrical impulses due to abnormal VGSC functional expression influenced by the latent virus.
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19
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A novel phospho-modulatory mechanism contributes to the calcium-dependent regulation of T-type Ca 2+ channels. Sci Rep 2019; 9:15642. [PMID: 31666636 PMCID: PMC6821770 DOI: 10.1038/s41598-019-52194-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2019] [Accepted: 10/13/2019] [Indexed: 11/08/2022] Open
Abstract
Cav3 / T-type Ca2+ channels are dynamically regulated by intracellular Ca2+ ions, which inhibit Cav3 availability. Here, we demonstrate that this inhibition becomes irreversible in the presence of non-hydrolysable ATP analogs, resulting in a strong hyperpolarizing shift in the steady-state inactivation of the residual Cav3 current. Importantly, the effect of these ATP analogs was prevented in the presence of intracellular BAPTA. Additional findings obtained using intracellular dialysis of inorganic phosphate and alkaline phosphatase or NaN3 treatment further support the involvement of a phosphorylation mechanism. Contrasting with Cav1 and Cav2 Ca2+ channels, the Ca2+-dependent modulation of Cav3 channels appears to be independent of calmodulin, calcineurin and endocytic pathways. Similar findings were obtained for the native T-type Ca2+ current recorded in rat thalamic neurons of the central medial nucleus. Overall, our data reveal a new Ca2+ sensitive phosphorylation-dependent mechanism regulating Cav3 channels, with potentially important physiological implications for the multiple cell functions controlled by T-type Ca2+ channels.
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20
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Mustafá ER, Cordisco Gonzalez S, Raingo J. Ghrelin Selectively Inhibits CaV3.3 Subtype of Low-Voltage-Gated Calcium Channels. Mol Neurobiol 2019; 57:722-735. [DOI: 10.1007/s12035-019-01738-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 08/16/2019] [Indexed: 01/01/2023]
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21
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Arteaga-Tlecuitl R, Sanchez-Sandoval AL, Ramirez-Cordero BE, Rosendo-Pineda MJ, Vaca L, Gomora JC. Increase of Ca V3 channel activity induced by HVA β1b-subunit is not mediated by a physical interaction. BMC Res Notes 2018; 11:810. [PMID: 30428904 PMCID: PMC6236959 DOI: 10.1186/s13104-018-3917-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/09/2018] [Indexed: 01/13/2023] Open
Abstract
Objective Low voltage-activated (LVA) calcium channels are crucial for regulating oscillatory behavior in several types of neurons and other excitable cells. LVA channels dysfunction has been implicated in epilepsy, neuropathic pain, cancer, among other diseases. Unlike for High Voltage-Activated (HVA) channels, voltage-dependence and kinetics of currents carried by recombinant LVA, i.e., CaV3 channels, are quite similar to those observed in native currents. Therefore, whether these channels are regulated by HVA auxiliary subunits, remain controversial. Here, we used the α1-subunits of CaV3.1, CaV3.2, and CaV3.3 channels, together with HVA auxiliary β-subunits to perform electrophysiological, confocal microscopy and immunoprecipitation experiments, in order to further explore this possibility. Results Functional expression of CaV3 channels is up-regulated by all four β-subunits, although most consistent effects were observed with the β1b-subunit. The biophysical properties of CaV3 channels were not modified by any β-subunit. Furthermore, although β1b-subunits increased colocalization of GFP-tagged CaV3 channels and the plasma membrane of HEK-293 cells, western blots analysis revealed the absence of physical interaction between CaV3.3 and β1b-subunits as no co-immunoprecipitation was observed. These results provide solid evidence that the up-regulation of LVA channels in the presence of HVA-β1b subunit is not mediated by a high affinity interaction between both proteins. Electronic supplementary material The online version of this article (10.1186/s13104-018-3917-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Rogelio Arteaga-Tlecuitl
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Ana Laura Sanchez-Sandoval
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Belen Ernestina Ramirez-Cordero
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Margarita Jacaranda Rosendo-Pineda
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Luis Vaca
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico
| | - Juan Carlos Gomora
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Mexico City, Mexico.
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22
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Wu J, Peng S, Xiao L, Cheng X, Kuang H, Zhu M, Zhang D, Jiang C, Liu T. Cell-Type Specific Distribution of T-Type Calcium Currents in Lamina II Neurons of the Rat Spinal Cord. Front Cell Neurosci 2018; 12:370. [PMID: 30386213 PMCID: PMC6199353 DOI: 10.3389/fncel.2018.00370] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2018] [Accepted: 09/28/2018] [Indexed: 12/19/2022] Open
Abstract
Spinal lamina II (substantia gelatinosa, SG) neurons integrate nociceptive information from the primary afferents and are classified according to electrophysiological (tonic firing, delayed firing, single spike, initial burst, phasic firing, gap firing and reluctant firing) or morphological (islet, central, vertical, radial and unclassified) criteria. T-type calcium (Cav3) channels play an essential role in the central mechanism of pathological pain, but the electrophysiological properties and the cell-type specific distribution of T-type channels in SG neurons have not been fully elucidated. To investigate the electrophysiological and morphological features of T-type channel-expressing or -lacking neurons, voltage- and current-clamp recordings were performed on either transverse or parasagittal spinal cord slices. Recording made in transverse spinal cord slices showed that an inward current (I T) was observed in 44.5% of the SG neurons that was fully blocked by Ni2+ and TTA-A2. The amplitude of I T depended on the magnitude and the duration of hyperpolarization pre-pulse. The voltage for eliciting and maximizing I T were -70 mV and -35 mV, respectively. In addition, we found that most of the I T-expressing neurons are tonic firing neurons and exhibit more negative action potential (AP) threshold and smaller difference of AP threshold and resting membrane potential (RMP) than those neurons lacking I T. Consistently, a specific T-type calcium channel blocker TTA-P2 increased the AP threshold and enlarged the difference between AP threshold and membrane potential (Ihold = 0). Meanwhile, the morphological analysis indicated that most of the I T-expressing neurons are islet neurons. In conclusion, we identify a cell-type specific distribution and the function of T-type channels in SG neurons. These findings might provide new insights into the mechanisms underlying the contribution of T-type channels in sensory transmission.
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Affiliation(s)
- Jing Wu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Sicong Peng
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Linghui Xiao
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Xiaoe Cheng
- Department of Anesthesiology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Haixia Kuang
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Mengye Zhu
- Department of Pain Clinic, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Daying Zhang
- Department of Pain Clinic, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Changyu Jiang
- Jisheng Han Academician Workstation for Pain Medicine, Nanshan Hospital, Shenzhen, China
| | - Tao Liu
- Department of Pediatrics, The First Affiliated Hospital of Nanchang University, Nanchang, China.,Jisheng Han Academician Workstation for Pain Medicine, Nanshan Hospital, Shenzhen, China.,Center for Experimental Medicine, The First Affiliated Hospital of Nanchang University, Nanchang, China
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23
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N'Gouemo P. Voltage-Sensitive Calcium Channels in the Brain: Relevance to Alcohol Intoxication and Withdrawal. Handb Exp Pharmacol 2018; 248:263-280. [PMID: 29500720 DOI: 10.1007/164_2018_93] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Voltage-sensitive Ca2+ (CaV) channels are the primary route of depolarization-induced Ca2+ entry in neurons and other excitable cells, leading to an increase in intracellular Ca2+ concentration ([Ca2+]i). The resulting increase in [Ca2+]i activates a wide range of Ca2+-dependent processes in neurons, including neurotransmitter release, gene transcription, activation of Ca2+-dependent enzymes, and activation of certain K+ channels and chloride channels. In addition to their key roles under physiological conditions, CaV channels are also an important target of alcohol, and alcohol-induced changes in Ca2+ signaling can disturb neuronal homeostasis, Ca2+-mediated gene transcription, and the function of neuronal circuits, leading to various neurological and/or neuropsychiatric symptoms and disorders, including alcohol withdrawal induced-seizures and alcoholism.
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Affiliation(s)
- Prosper N'Gouemo
- Department of Pediatrics, Georgetown University Medical Center, Washington, DC, USA.
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24
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Fogerson PM, Huguenard JR. Tapping the Brakes: Cellular and Synaptic Mechanisms that Regulate Thalamic Oscillations. Neuron 2017; 92:687-704. [PMID: 27883901 DOI: 10.1016/j.neuron.2016.10.024] [Citation(s) in RCA: 98] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/03/2016] [Accepted: 10/10/2016] [Indexed: 12/26/2022]
Abstract
Thalamic oscillators contribute to both normal rhythms associated with sleep and anesthesia and abnormal, hypersynchronous oscillations that manifest behaviorally as absence seizures. In this review, we highlight new findings that refine thalamic contributions to cortical rhythms and suggest that thalamic oscillators may be subject to both local and global control. We describe endogenous thalamic mechanisms that limit network synchrony and discuss how these protective brakes might be restored to prevent absence seizures. Finally, we describe how intrinsic and circuit-level specializations among thalamocortical loops may determine their involvement in widespread oscillations and render subsets of thalamic nuclei especially vulnerable to pathological synchrony.
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Affiliation(s)
- P Michelle Fogerson
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - John R Huguenard
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA.
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25
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Nicholson E, Kullmann DM. T-type calcium channels contribute to NMDA receptor independent synaptic plasticity in hippocampal regular-spiking oriens-alveus interneurons. J Physiol 2017; 595:3449-3458. [PMID: 28134447 PMCID: PMC5451714 DOI: 10.1113/jp273695] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 01/06/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Regular-spiking interneurons in the hippocampal stratum oriens exhibit a form of long-term potentiation of excitatory transmission that is independent of NMDA receptors but requires co-activation of Ca2+ -permeable AMPA receptors and group I metabotropic glutamate receptors. We show that T-type Ca2+ channels are present in such interneurons. Blockade of T-type currents prevents the induction of long-term potentiation, and also interferes with long-lasting potentiation induced either by postsynaptic trains of action potentials or by pairing postsynaptic hyperpolarization with activation of group I metabotropic receptors. Several Ca2+ sources thus converge on the induction of NMDA receptor independent synaptic plasticity. ABSTRACT NMDA receptor independent long-term potentiation (LTP) in hippocampal stratum oriens-alveus (O/A) interneurons requires co-activation of postsynaptic group I metabotropic glutamate receptors (mGluRs) and Ca2+ -permeable AMPA receptors. The rectification properties of such AMPA receptors contribute to the preferential induction of LTP at hyperpolarized potentials. A persistent increase in excitatory transmission can also be triggered by exogenous activation of group I mGluRs at the same time as the interneuron is hyperpolarized, or by postsynaptic trains of action potentials in the absence of presynaptic stimulation. In the present study, we identify low-threshold transient (T-type) channels as a further source of Ca2+ that contributes to synaptic plasticity. T-type Ca2+ currents were detected in mouse regular-spiking O/A interneurons. Blocking T-type currents pharmacologically prevented LTP induced by high-frequency stimulation of glutamatergic axons, or by application of the group I mGluR agonist dihydroxyphenylglycine, paired with postsynaptic hyperpolarization. T-type current blockade also prevented synaptic potentiation induced by postsynaptic action potential trains. Several sources of Ca2+ thus converge on NMDA receptor independent LTP induction in O/A interneurons.
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Cazade M, Bidaud I, Lory P, Chemin J. Activity-dependent regulation of T-type calcium channels by submembrane calcium ions. eLife 2017; 6. [PMID: 28109159 PMCID: PMC5308894 DOI: 10.7554/elife.22331] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 01/20/2017] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated Ca2+ channels are involved in numerous physiological functions and various mechanisms finely tune their activity, including the Ca2+ ion itself. This is well exemplified by the Ca2+-dependent inactivation of L-type Ca2+ channels, whose alteration contributes to the dramatic disease Timothy Syndrome. For T-type Ca2+ channels, a long-held view is that they are not regulated by intracellular Ca2+. Here we challenge this notion by using dedicated electrophysiological protocols on both native and expressed T-type Ca2+ channels. We demonstrate that a rise in submembrane Ca2+ induces a large decrease in T-type current amplitude due to a hyperpolarizing shift in the steady-state inactivation. Activation of most representative Ca2+-permeable ionotropic receptors similarly regulate T-type current properties. Altogether, our data clearly establish that Ca2+ entry exerts a feedback control on T-type channel activity, by modulating the channel availability, a mechanism that critically links cellular properties of T-type Ca2+ channels to their physiological roles. DOI:http://dx.doi.org/10.7554/eLife.22331.001 Neurons, muscle cells and many other types of cells use electrical signals to exchange information and coordinate their behavior. Proteins known as calcium channels sit in the membrane that surrounds the cell and can generate electrical signals by allowing calcium ions to cross the membrane and enter the cell during electrical activities. Although calcium ions are needed to generate these electrical signals, and for many other processes in cells, if the levels of calcium ions inside cells become too high they can be harmful and cause disease. Cells have a “feedback” mechanism that prevents calcium ion levels from becoming too high. This mechanism relies on the calcium ions that are already in the cell being able to close the calcium channels. This feedback mechanism has been extensively studied in two types of calcium channel, but it is not known whether a third group of channels – known as Cav3 channels – are also regulated in this way. Cav3 channels are important in electrical signaling in neurons and have been linked with epilepsy, chronic pain and various other conditions in humans. Cazade et al. investigated whether calcium ions can regulate the activity of human Cav3 channels. The experiments show that these channels are indeed regulated by calcium ions, but using a distinct mechanism to other types of calcium channels. For the Cav3 channels, calcium ions alter the gating properties of the channels so that they are less easily activated . As a result, fewer Cav3 channels are “available” to provide calcium ions with a route into the cell. The next steps following on from this work will be to identify the molecular mechanisms underlying this new feedback mechanism. Another challenge will be to find out what role this calcium ion-driven feedback plays in neurological disorders that are linked with altered Cav3 channel activity. DOI:http://dx.doi.org/10.7554/eLife.22331.002
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Affiliation(s)
- Magali Cazade
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Isabelle Bidaud
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Philippe Lory
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
| | - Jean Chemin
- IGF, CNRS, INSERM, University of Montpellier, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics', Montpellier, France
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27
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Wang H, Zhang X, Xue L, Xing J, Jouvin MH, Putney JW, Anderson MP, Trebak M, Kinet JP. Low-Voltage-Activated CaV3.1 Calcium Channels Shape T Helper Cell Cytokine Profiles. Immunity 2016; 44:782-94. [PMID: 27037192 DOI: 10.1016/j.immuni.2016.01.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 12/30/2015] [Accepted: 01/22/2016] [Indexed: 12/15/2022]
Abstract
Activation of T cells is mediated by the engagement of T cell receptors (TCRs) followed by calcium entry via store-operated calcium channels. Here we have shown an additional route for calcium entry into T cells-through the low-voltage-activated T-type CaV3.1 calcium channel. CaV3.1 mediated a substantial current at resting membrane potentials, and its deficiency had no effect on TCR-initiated calcium entry. Mice deficient for CaV3.1 were resistant to the induction of experimental autoimmune encephalomyelitis and had reduced productions of the granulocyte-macrophage colony-stimulating factor (GM-CSF) by central nervous system (CNS)-infiltrating T helper 1 (Th1) and Th17 cells. CaV3.1 deficiency led to decreased secretion of GM-CSF from in vitro polarized Th1 and Th17 cells. Nuclear translocation of the nuclear factor of activated T cell (NFAT) was also reduced in CaV3.1-deficient T cells. These data provide evidence for T-type channels in immune cells and their potential role in shaping the autoimmune response.
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Affiliation(s)
- Huiyun Wang
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - Xuexin Zhang
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Li Xue
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - Juan Xing
- Laboratory of Signal Transduction, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Marie-Hélène Jouvin
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - James W Putney
- Laboratory of Signal Transduction, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Matthew P Anderson
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA; Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA
| | - Mohamed Trebak
- Department of Cellular and Molecular Physiology, Penn State University College of Medicine, Hershey, PA 17033, USA
| | - Jean-Pierre Kinet
- Department of Pathology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02115, USA.
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28
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Rossier MF. T-Type Calcium Channel: A Privileged Gate for Calcium Entry and Control of Adrenal Steroidogenesis. Front Endocrinol (Lausanne) 2016; 7:43. [PMID: 27242667 PMCID: PMC4873500 DOI: 10.3389/fendo.2016.00043] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/05/2016] [Indexed: 12/03/2022] Open
Abstract
Intracellular calcium plays a crucial role in modulating a variety of functions such as muscle contraction, hormone secretion, gene expression, or cell growth. Calcium signaling has been however shown to be more complex than initially thought. Indeed, it is confined within cell microdomains, and different calcium channels are associated with different functions, as shown by various channelopathies. Sporadic mutations on voltage-operated L-type calcium channels in adrenal glomerulosa cells have been shown recently to be the second most prevalent genetic abnormalities present in human aldosterone-producing adenoma. The observed modification of the threshold of activation of the mutated channels not only provides an explanation for this gain of function but also reminds us on the importance of maintaining adequate electrophysiological characteristics to make channels able to exert specific cellular functions. Indeed, the contribution to steroid production of the various calcium channels expressed in adrenocortical cells is not equal, and the reason has been investigated for a long time. Given the very negative resting potential of these cells, and the small membrane depolarization induced by their physiological agonists, low threshold T-type calcium channels are particularly well suited for responding under these conditions and conveying calcium into the cell, at the right place for controlling steroidogenesis. In contrast, high threshold L-type channels are normally activated by much stronger cell depolarizations. The fact that dihydropyridine calcium antagonists, specific for L-type channels, are poorly efficient for reducing aldosterone secretion either in vivo or in vitro, strongly supports the view that these two types of channels differently affect steroid biosynthesis. Whether a similar analysis is transposable to fasciculata cells and cortisol secretion is one of the questions addressed in the present review. No similar mutations on L-type or T-type channels have been described yet to affect cortisol secretion or to be linked to the development of Cushing syndrome, but several evidences suggest that the function of T channels is also crucial in fasciculata cells. Putative molecular mechanisms and cellular structural organization making T channels a privileged entry for the "steroidogenic calcium" are also discussed.
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Affiliation(s)
- Michel F. Rossier
- Service of Clinical Chemistry and Toxicology, Hospital of Valais, Sion, Switzerland
- Department of Human Protein Science, Faculty of Medicine, University of Geneva, Geneva, Switzerland
- *Correspondence: Michel F. Rossier,
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29
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Ca-α1T, a fly T-type Ca2+ channel, negatively modulates sleep. Sci Rep 2015; 5:17893. [PMID: 26647714 PMCID: PMC4673464 DOI: 10.1038/srep17893] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 11/06/2015] [Indexed: 01/14/2023] Open
Abstract
Mammalian T-type Ca2+ channels are encoded by three separate genes (Cav3.1, 3.2, 3.3). These channels are reported to be sleep stabilizers important in the generation of the delta rhythms of deep sleep, but controversy remains. The identification of precise physiological functions for the T-type channels has been hindered, at least in part, by the potential for compensation between the products of these three genes and a lack of specific pharmacological inhibitors. Invertebrates have only one T-type channel gene, but its functions are even less well-studied. We cloned Ca-α1T, the only Cav3 channel gene in Drosophila melanogaster, expressed it in Xenopus oocytes and HEK-293 cells, and confirmed it passes typical T-type currents. Voltage-clamp analysis revealed the biophysical properties of Ca-α1T show mixed similarity, sometimes falling closer to Cav3.1, sometimes to Cav3.2, and sometimes to Cav3.3. We found Ca-α1T is broadly expressed across the adult fly brain in a pattern vaguely reminiscent of mammalian T-type channels. In addition, flies lacking Ca-α1T show an abnormal increase in sleep duration most pronounced during subjective day under continuous dark conditions despite normal oscillations of the circadian clock. Thus, our study suggests invertebrate T-type Ca2+ channels promote wakefulness rather than stabilizing sleep.
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30
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González-Rodríguez P, Falcón D, Castro MJ, Ureña J, López-Barneo J, Castellano A. Hypoxic induction of T-type Ca(2+) channels in rat cardiac myocytes: role of HIF-1α and RhoA/ROCK signalling. J Physiol 2015; 593:4729-45. [PMID: 26331302 DOI: 10.1113/jp271053] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 08/24/2015] [Indexed: 01/08/2023] Open
Abstract
T-type Ca(2+) channels are expressed in the ventricular myocytes of the fetal and perinatal heart, but are normally downregulated as development progresses. Interestingly, however, these channels are re-expressed in adult cardiomyocytes under pathological conditions. We investigated low voltage-activated T-type Ca(2+) channel regulation in hypoxia in rat cardiomyocytes. Molecular studies revealed that hypoxia induces the upregulation of Cav 3.2 mRNA, whereas Cav 3.1 mRNA is not significantly altered. The effect of hypoxia on Cav 3.2 mRNA was time- and dose-dependent, and required hypoxia inducible factor-1α (HIF-1α) stabilization. Patch-clamp recordings confirmed that T-type Ca(2+) channel currents were upregulated in hypoxic conditions, and the addition of 50 μm NiCl2 (a T-type channel blocker) demonstrated that the Cav 3.2 channel is responsible for this upregulation. This increase in current density was not accompanied by significant changes in the Cav 3.2 channel electrophysiological properties. The small monomeric G-protein RhoA and its effector Rho-associated kinase I (ROCKI), which are known to play important roles in cardiovascular physiology, were also upregulated in neonatal rat ventricular myocytes subjected to hypoxia. Pharmacological experiments indicated that both proteins were involved in the observed upregulation of the Cav 3.2 channel and the stabilization of HIF-1α that occurred in response to hypoxia. These results suggest a possible role for Cav 3.2 channels in the increased probability of developing arrhythmias observed in ischaemic situations, and in the pathogenesis of diseases associated with hypoxic Ca(2+) overload.
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Affiliation(s)
- P González-Rodríguez
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
| | - D Falcón
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
| | - M J Castro
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain
| | - J Ureña
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
| | - J López-Barneo
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
| | - A Castellano
- Instituto de Biomedicina de Sevilla (IBiS), Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, Sevilla, Spain.,Departamento de Fisiología Médica y Biofísica, Facultad de Medicina, Universidad de Sevilla, Sevilla, Spain
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31
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A concerted action of L- and T-type Ca2+ channels regulates locus coeruleus pacemaking. Mol Cell Neurosci 2015; 68:293-302. [DOI: 10.1016/j.mcn.2015.08.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Revised: 08/18/2015] [Accepted: 08/21/2015] [Indexed: 11/18/2022] Open
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32
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Weaver EM, Zamora FJ, Puplampu-Dove YA, Kiessu E, Hearne JL, Martin-Caraballo M. Regulation of T-type calcium channel expression by sodium butyrate in prostate cancer cells. Eur J Pharmacol 2015; 749:20-31. [DOI: 10.1016/j.ejphar.2014.12.021] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 12/15/2014] [Accepted: 12/15/2014] [Indexed: 10/24/2022]
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33
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Perissinotti PP, Ethington EA, Almazan E, Martínez-Hernández E, Kalil J, Koob MD, Piedras-Rentería ES. Calcium current homeostasis and synaptic deficits in hippocampal neurons from Kelch-like 1 knockout mice. Front Cell Neurosci 2015; 8:444. [PMID: 25610372 PMCID: PMC4285801 DOI: 10.3389/fncel.2014.00444] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/10/2014] [Indexed: 11/30/2022] Open
Abstract
Kelch-like 1 (KLHL1) is a neuronal actin-binding protein that modulates voltage-gated CaV2.1 (P/Q-type) and CaV3.2 (α1H T-type) calcium channels; KLHL1 knockdown experiments (KD) cause down-regulation of both channel types and altered synaptic properties in cultured rat hippocampal neurons (Perissinotti et al., 2014). Here, we studied the effect of ablation of KLHL1 on calcium channel function and synaptic properties in cultured hippocampal neurons from KLHL1 knockout (KO) mice. Western blot data showed the P/Q-type channel α1A subunit was less abundant in KO hippocampus compared to wildtype (WT); and P/Q-type calcium currents were smaller in KO neurons than WT during early days in vitro, although this decrease was compensated for at late stages by increases in L-type calcium current. In contrast, T-type currents did not change in culture. However, biophysical properties and western blot analysis revealed a differential contribution of T-type channel isoforms in the KO, with CaV3.2 α1H subunit being down-regulated and CaV3.1 α1G up-regulated. Synapsin I levels were also reduced in the KO hippocampus and cultured neurons displayed a concomitant reduction in synapsin I puncta and decreased miniature excitatory postsynaptic current (mEPSC) frequency. In summary, genetic ablation of the calcium channel modulator resulted in compensatory mechanisms to maintain calcium current homeostasis in hippocampal KO neurons; however, synaptic alterations resulted in a reduction of excitatory synapse number, causing an imbalance of the excitatory-inhibitory synaptic input ratio favoring inhibition.
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Affiliation(s)
- Paula P Perissinotti
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
| | - Elizabeth A Ethington
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
| | - Erik Almazan
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
| | - Elizabeth Martínez-Hernández
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
| | - Jennifer Kalil
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
| | - Michael D Koob
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota Minneapolis, MN, USA
| | - Erika S Piedras-Rentería
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA ; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine Maywood, IL, USA
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34
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Tuckwell HC, Penington NJ. Computational modeling of spike generation in serotonergic neurons of the dorsal raphe nucleus. Prog Neurobiol 2014; 118:59-101. [PMID: 24784445 DOI: 10.1016/j.pneurobio.2014.04.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Revised: 04/14/2014] [Accepted: 04/21/2014] [Indexed: 01/14/2023]
Abstract
Serotonergic neurons of the dorsal raphe nucleus, with their extensive innervation of limbic and higher brain regions and interactions with the endocrine system have important modulatory or regulatory effects on many cognitive, emotional and physiological processes. They have been strongly implicated in responses to stress and in the occurrence of major depressive disorder and other psychiatric disorders. In order to quantify some of these effects, detailed mathematical models of the activity of such cells are required which describe their complex neurochemistry and neurophysiology. We consider here a single-compartment model of these neurons which is capable of describing many of the known features of spike generation, particularly the slow rhythmic pacemaking activity often observed in these cells in a variety of species. Included in the model are 11 kinds of ion channels: a fast sodium current INa, a delayed rectifier potassium current IKDR, a transient potassium current IA, a slow non-inactivating potassium current IM, a low-threshold calcium current IT, two high threshold calcium currents IL and IN, small and large conductance potassium currents ISK and IBK, a hyperpolarization-activated cation current IH and a leak current ILeak. In Sections 3-8, each current type is considered in detail and parameters estimated from voltage clamp data where possible. Three kinds of model are considered for the BK current and two for the leak current. Intracellular calcium ion concentration Cai is an additional component and calcium dynamics along with buffering and pumping is discussed in Section 9. The remainder of the article contains descriptions of computed solutions which reveal both spontaneous and driven spiking with several parameter sets. Attention is focused on the properties usually associated with these neurons, particularly long duration of action potential, steep upslope on the leading edge of spikes, pacemaker-like spiking, long-lasting afterhyperpolarization and the ramp-like return to threshold after a spike. In some cases the membrane potential trajectories display doublets or have humps or notches as have been reported in some experimental studies. The computed time courses of IA and IT during the interspike interval support the generally held view of a competition between them in influencing the frequency of spiking. Spontaneous activity was facilitated by the presence of IH which has been found in these neurons by some investigators. For reasonable sets of parameters spike frequencies between about 0.6Hz and 1.2Hz are obtained, but frequencies as high as 6Hz could be obtained with special parameter choices. Topics investigated and compared with experiment include shoulders, notches, anodal break phenomena, the effects of noradrenergic input, frequency versus current curves, depolarization block, effects of cell size and the effects of IM. The inhibitory effects of activating 5-HT1A autoreceptors are also investigated. There is a considerable discussion of in vitro versus in vivo firing behavior, with focus on the roles of noradrenergic input, corticotropin-releasing factor and orexinergic inputs. Location of cells within the nucleus is probably a major factor, along with the state of the animal.
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Affiliation(s)
- Henry C Tuckwell
- Max Planck Institute for Mathematics in the Sciences, Inselstr. 22, 04103 Leipzig, Germany; School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, South Australia 5005, Australia.
| | - Nicholas J Penington
- Department of Physiology and Pharmacology, State University of New York, Downstate Medical Center, Box 29, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA; Program in Neural and Behavioral Science and Robert F. Furchgott Center for Neural and Behavioral Science, State University of New York, Downstate Medical Center, Box 29, 450 Clarkson Avenue, Brooklyn, NY 11203-2098, USA
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35
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González-Ramírez R, Martínez-Hernández E, Sandoval A, Felix R. Transcription factor Sp1 regulates T-type Ca(2+) channel CaV 3.1 gene expression. J Cell Physiol 2014; 229:551-60. [PMID: 23868804 DOI: 10.1002/jcp.24432] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 07/11/2013] [Indexed: 01/30/2023]
Abstract
Voltage-gated T-type Ca(2+) (CaV 3) channels mediate a number of physiological events in developing and mature cells, and are implicated in neurological and cardiovascular diseases. In mammals, there are three distinct T-channel genes (CACNA1G, CACNA1H, and CACNA1I) encoding proteins (CaV 3.1-CaV 3.3) that differ in their localization as well as in molecular, biophysical, and pharmacological properties. The CACNA1G is a large gene that contains 38 exons and is localized in chromosome 17q22. Only basic characteristics of the CACNA1G gene promoter region have been investigated classifying it as a TATA-less sequence containing several potential transcription factor-binding motifs. Here, we cloned and characterized a proximal promoter region and initiated the analysis of transcription factors that control CaV 3.1 channel expression using the murine Cacna1g gene as a model. We isolated a ∼1.5 kb 5'-upstream region of Cacna1g and verified its transcriptional activity in the mouse neuroblastoma N1E-115 cell line. In silico analysis revealed that this region possesses a TATA-less minimal promoter that includes two potential transcription start sites and four binding sites for the transcription factor Sp1. The ability of one of these sites to interact with the transcription factor was confirmed by electrophoretic mobility shift assays. Consistent with this, Sp1 over-expression enhanced promoter activity while siRNA-mediated Sp1 silencing significantly decreased the level of CaV 3.1 protein and reduced the amplitude of whole-cell T-type Ca(2+) currents expressed in the N1E-115 cells. These results provide new insights into the molecular mechanisms that control CaV 3.1 channel expression.
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Affiliation(s)
- Ricardo González-Ramírez
- Department of Molecular Biology and Histocompatibility, "Dr. Manuel Gea González" General Hospital, Mexico City, Mexico
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36
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Perissinotti PP, Ethington EG, Cribbs L, Koob MD, Martin J, Piedras-Rentería ES. Down-regulation of endogenous KLHL1 decreases voltage-gated calcium current density. Cell Calcium 2014; 55:269-80. [PMID: 24703904 DOI: 10.1016/j.ceca.2014.03.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Revised: 03/04/2014] [Accepted: 03/09/2014] [Indexed: 10/25/2022]
Abstract
The actin-binding protein Kelch-like 1 (KLHL1) can modulate voltage-gated calcium channels in vitro. KLHL1 interacts with actin and with the pore-forming subunits of Cav2.1 and CaV3.2 calcium channels, resulting in up-regulation of P/Q and T-type current density. Here we tested whether endogenous KLHL1 modulates voltage gated calcium currents in cultured hippocampal neurons by down-regulating the expression of KLHL1 via adenoviral delivery of shRNA targeted against KLHL1 (shKLHL1). Control adenoviruses did not affect any of the neuronal properties measured, yet down-regulation of KLHL1 resulted in HVA current densities ~68% smaller and LVA current densities 44% smaller than uninfected controls, with a concomitant reduction in α(1A) and α(1H) protein levels. Biophysical analysis and western blot experiments suggest Ca(V)3.1 and 3.3 currents are also present in shKLHL1-infected neurons. Synapsin I levels, miniature postsynaptic current frequency, and excitatory and inhibitory synapse number were reduced in KLHL1 knockdown. This study corroborates the physiological role of KLHL1 as a calcium channel modulator and demonstrates a novel, presynaptic role.
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Affiliation(s)
- Paula P Perissinotti
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Elizabeth G Ethington
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Leanne Cribbs
- Office of Research Services, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Michael D Koob
- Institute for Translational Neuroscience, Department of Lab Medicine & Pathology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jody Martin
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA
| | - Erika S Piedras-Rentería
- Cell and Molecular Physiology Department, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA; Neuroscience Institute, Loyola University Chicago, Stritch School of Medicine, 2160 S. First Avenue, Maywood, IL 60153, USA.
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37
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T-type Ca2+ channels in absence epilepsy. Pflugers Arch 2014; 466:719-34. [DOI: 10.1007/s00424-014-1461-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Accepted: 01/22/2014] [Indexed: 11/25/2022]
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Fry CH, Jabr RI. T-type Ca2+ channels and the urinary and male genital tracts. Pflugers Arch 2014; 466:781-9. [PMID: 24463704 DOI: 10.1007/s00424-014-1446-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 01/06/2014] [Accepted: 01/07/2014] [Indexed: 11/26/2022]
Abstract
T-type Ca(2+) channels are widely expressed throughout the urinary and male genital tracts, generally alongside L-type Ca(2+) channels. The use of pharmacological blockers of these channels has suggested functional roles in all regions, with the possible exception of the ureter. Their functional expression is apparent not just in smooth muscle cells but also in interstitial cells that lie in close proximity to muscle, nerve and epithelial components of these tissues. Thus, T-type Ca(2+) channels can contribute directly to modulation of muscle function and indirectly to changes of epithelial and nerve function. T-type Ca(2+) channel activity modulates phasic contractile activity, especially in conjunction with Ca(2+)-activated K(+) channels, and also to agonist-dependent responses in different tissues. Upregulation of channel density occurs in pathological conditions associated with enhanced contractile responses, e.g. overactive bladder, but it is unclear if this is causal or a response to the pathological state. Moreover, T-type Ca(2+) channels may have a role in the development of prostate tumours regulating the secretion of mitogens from neuroendocrine cells. Although a number of selective channel blockers exist, their relative selectivity over L-type Ca(2+) channels is often low and makes evaluation of T-type Ca(2+) channel function in the whole organism difficult.
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Affiliation(s)
- C H Fry
- Department of Biochemistry and Physiology, University of Surrey, Guildford, GU2 7XH, UK,
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39
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Zhang C, Tonsfeldt KJ, Qiu J, Bosch MA, Kobayashi K, Steiner RA, Kelly MJ, Rønnekleiv OK. Molecular mechanisms that drive estradiol-dependent burst firing of Kiss1 neurons in the rostral periventricular preoptic area. Am J Physiol Endocrinol Metab 2013; 305:E1384-97. [PMID: 24105416 PMCID: PMC3882370 DOI: 10.1152/ajpendo.00406.2013] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Kisspeptin (Kiss1) neurons in the rostral periventricular area of the third ventricle (RP3V) provide excitatory drive to gonadotropin-releasing hormone (GnRH) neurons to control fertility. Using whole cell patch clamp recording and single-cell (sc)RT-PCR techniques targeting Kiss1-CreGFP or tyrosine hydroxylase (TH)-EGFP neurons, we characterized the biophysical properties of these neurons and identified the critical intrinsic properties required for burst firing in 17β-estradiol (E2)-treated, ovariectomized female mice. One-fourth of the RP3V Kiss1 neurons exhibited spontaneous burst firing. RP3V Kiss1 neurons expressed a hyperpolarization-activated h-current (Ih) and a T-type calcium current (IT), which supported hyperpolarization-induced rebound burst firing. Under voltage clamp conditions, all Kiss1 neurons expressed a kinetically fast Ih that was augmented 3.4-fold by high (LH surge-producing)-E2 treatment. scPCR analysis of Kiss1 neurons revealed abundant expression of the HCN1 channel transcripts. Kiss1 neurons also expressed a Ni(2+)- and TTA-P2-sensitive IT that was augmented sixfold with high-E2 treatment. CaV3.1 mRNA was also highly expressed in these cells. Current clamp analysis revealed that rebound burst firing was induced in RP3V Kiss1 neurons in high-E2-treated animals, and the majority of Kiss1 neurons had a hyperpolarization threshold of -84.7 mV, which corresponded to the V½ for IT de-inactivation. Finally, Kiss1 neurons in the RP3V were hyperpolarized by μ- and κ-opioid and GABAB receptor agonists, suggesting that these pathways also contribute to rebound burst firing. Therefore, Kiss1 neurons in the RP3V express the critical channels and receptors that permit E2-dependent rebound burst firing and provide the biophysical substrate that drives the preovulatory surge of GnRH.
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Affiliation(s)
- Chunguang Zhang
- Department of Physiology and Pharmacology, Oregon Health and Science University, Portland Oregon
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40
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Abstract
Low-voltage-activated T-type Ca(2+) channels are widely expressed in various types of neurons. Once deinactivated by hyperpolarization, T-type channels are ready to be activated by a small depolarization near the resting membrane potential and, therefore, are optimal for regulating the excitability and electroresponsiveness of neurons under physiological conditions near resting states. Ca(2+) influx through T-type channels engenders low-threshold Ca(2+) spikes, which in turn trigger a burst of action potentials. Low-threshold burst firing has been implicated in the synchronization of the thalamocortical circuit during sleep and in absence seizures. It also has been suggested that T-type channels play an important role in pain signal transmission, based on their abundant expression in pain-processing pathways in peripheral and central neurons. In this review, we will describe studies on the role of T-type Ca(2+) channels in the physiological as well as pathological generation of brain rhythms in sleep, absence epilepsy, and pain signal transmission. Recent advances in studies of T-type channels in the control of cognition will also be briefly discussed.
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Affiliation(s)
- Eunji Cheong
- Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
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41
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Demers-Giroux PO, Bourdin B, Sauvé R, Parent L. Cooperative activation of the T-type CaV3.2 channel: interaction between Domains II and III. J Biol Chem 2013; 288:29281-93. [PMID: 23970551 PMCID: PMC3795230 DOI: 10.1074/jbc.m113.500975] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 08/02/2013] [Indexed: 12/28/2022] Open
Abstract
T-type CaV3 channels are important mediators of Ca(2+) entry near the resting membrane potential. Little is known about the molecular mechanisms responsible for channel activation. Homology models based upon the high-resolution structure of bacterial NaV channels predict interaction between the S4-S5 helix of Domain II (IIS4-S5) and the distal S6 pore region of Domain II (IIS6) and Domain III (IIIS6). Functional intra- and inter-domain interactions were investigated with a double mutant cycle analysis. Activation gating and channel kinetics were measured for 47 single mutants and 20 pairs of mutants. Significant coupling energies (ΔΔG(interact) ≥ 1.5 kcal mol(-1)) were measured for 4 specific pairs of mutants introduced between IIS4-S5 and IIS6 and between IIS4-S5 and IIIS6. In agreement with the computer based models, Thr-911 in IIS4-S5 was functionally coupled with Ile-1013 in IIS6 during channel activation. The interaction energy was, however, found to be stronger between Val-907 in IIS4-S5 and Ile-1013 in IIS6. In addition Val-907 was significantly coupled with Asn-1548 in IIIS6 but not with Asn-1853 in IVS6. Altogether, our results demonstrate that the S4-S5 and S6 helices from adjacent domains are energetically coupled during the activation of a low voltage-gated T-type CaV3 channel.
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Affiliation(s)
- Pierre-Olivier Demers-Giroux
- From the Département de Physiologie, Membrane Protein Research Group, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Benoîte Bourdin
- From the Département de Physiologie, Membrane Protein Research Group, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Rémy Sauvé
- From the Département de Physiologie, Membrane Protein Research Group, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
| | - Lucie Parent
- From the Département de Physiologie, Membrane Protein Research Group, Université de Montréal, Montréal, Quebec H3C 3J7, Canada
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42
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Lambert RC, Bessaïh T, Crunelli V, Leresche N. The many faces of T-type calcium channels. Pflugers Arch 2013; 466:415-23. [PMID: 24043572 DOI: 10.1007/s00424-013-1353-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 09/06/2013] [Accepted: 09/07/2013] [Indexed: 01/27/2023]
Abstract
Since the discovery of low-voltage-activated T-type calcium channels in sensory neurons and the initial characterization of their physiological function mainly in inferior olive and thalamic neurons, studies on neuronal T-type currents have predominantly focused on the generation of low-threshold spike (and associated action potential burst firing) which is strictly conditioned by a preceding hyperpolarization. This T-type current mediated activity has become an archetype of the function of these channels, constraining our view of the potential physiological and pathological roles that they may play in controlling the excitability of single cells and neural networks. However, greatly helped by the recent availability of the first potent and selective antagonists for this class of calcium channels, novel T-type current functions are rapidly being uncovered, including their surprising involvement in neuronal excitability at depolarized membrane potentials and their complex control of dendritic integration and neurotransmitter release. These and other data summarized in this short review clearly indicate a much wider physiological involvement of T-type channels in neuronal activity than previously expected.
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43
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Enyeart JJ, Enyeart JA. Ca2+ and K+ channels of normal human adrenal zona fasciculata cells: properties and modulation by ACTH and AngII. ACTA ACUST UNITED AC 2013; 142:137-55. [PMID: 23858003 PMCID: PMC3727308 DOI: 10.1085/jgp.201310964] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In whole cell patch clamp recordings, we found that normal human adrenal zona fasciculata (AZF) cells express voltage-gated, rapidly inactivating Ca2+ and K+ currents and a noninactivating, leak-type K+ current. Characterization of these currents with respect to voltage-dependent gating and kinetic properties, pharmacology, and modulation by the peptide hormones adrenocorticotropic hormone (ACTH) and AngII, in conjunction with Northern blot analysis, identified these channels as Cav3.2 (encoded by CACNA1H), Kv1.4 (KCNA4), and TREK-1 (KCNK2). In particular, the low voltage–activated, rapidly inactivating and slowly deactivating Ca2+ current (Cav3.2) was potently blocked by Ni2+ with an IC50 of 3 µM. The voltage-gated, rapidly inactivating K+ current (Kv1.4) was robustly expressed in nearly every cell, with a current density of 95.0 ± 7.2 pA/pF (n = 64). The noninactivating, outwardly rectifying K+ current (TREK-1) grew to a stable maximum over a period of minutes when recording at a holding potential of −80 mV. This noninactivating K+ current was markedly activated by cinnamyl 1-3,4-dihydroxy-α-cyanocinnamate (CDC) and arachidonic acid (AA) and inhibited almost completely by forskolin, properties which are specific to TREK-1 among the K2P family of K+ channels. The activation of TREK-1 by AA and inhibition by forskolin were closely linked to membrane hyperpolarization and depolarization, respectively. ACTH and AngII selectively inhibited the noninactivating K+ current in human AZF cells at concentrations that stimulated cortisol secretion. Accordingly, mibefradil and CDC at concentrations that, respectively, blocked Cav3.2 and activated TREK-1, each inhibited both ACTH- and AngII-stimulated cortisol secretion. These results characterize the major Ca2+ and K+ channels expressed by normal human AZF cells and identify TREK-1 as the primary leak-type channel involved in establishing the membrane potential. These findings also suggest a model for cortisol secretion in human AZF cells wherein ACTH and AngII receptor activation is coupled to membrane depolarization and the activation of Cav3.2 channels through inhibition of hTREK-1.
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Affiliation(s)
- John J Enyeart
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA.
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44
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Hansen PBL. Functional and pharmacological consequences of the distribution of voltage-gated calcium channels in the renal blood vessels. Acta Physiol (Oxf) 2013; 207:690-9. [PMID: 23351056 DOI: 10.1111/apha.12070] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Revised: 11/26/2012] [Accepted: 01/22/2013] [Indexed: 12/15/2022]
Abstract
Calcium channel blockers are widely used to treat hypertension because they inhibit voltage-gated calcium channels that mediate transmembrane calcium influx in, for example, vascular smooth muscle and cardiomyocytes. The calcium channel family consists of several subfamilies, of which the L-type is usually associated with vascular contractility. However, the L-, T- and P-/Q-types of calcium channels are present in the renal vasculature and are differentially involved in controlling vascular contractility, thereby contributing to regulation of kidney function and blood pressure. In the preglomerular vascular bed, all the three channel families are present. However, the T-type channel is the only channel in cortical efferent arterioles which is in contrast to the juxtamedullary efferent arteriole, and that leads to diverse functional effects of L- and T-type channel inhibition. Furthermore, by different mechanisms, T-type channels may contribute to both constriction and dilation of the arterioles. Finally, P-/Q-type channels are involved in the regulation of human intrarenal arterial contractility. The calcium blockers used in the clinic affect not only L-type but also P-/Q- and T-type channels. Therefore, the distinct effect obtained by inhibiting a given subtype or set of channels under experimental settings should be considered when choosing a calcium blocker for treatment. T-type channels seem to be crucial for regulating the GFR and the filtration fraction. Use of blockers is expected to lead to preferential efferent vasodilation, reduction of glomerular pressure and proteinuria. Therefore, renovascular T-type channels might provide novel therapeutic targets, and may have superior renoprotective effects compared to conventional calcium blockers.
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Affiliation(s)
- P. B. L. Hansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense; Denmark
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45
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Cheong E, Shin HS. T-type Ca²⁺ channels in absence epilepsy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:1560-71. [PMID: 23416255 DOI: 10.1016/j.bbamem.2013.02.002] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Revised: 01/15/2013] [Accepted: 02/01/2013] [Indexed: 11/28/2022]
Abstract
Low-voltage-activated T-type Ca²⁺ channels are highly expressed in the thalamocortical circuit, suggesting that they play a role in this brain circuit. Indeed, low-threshold burst firing mediated by T-type Ca²⁺ channels has long been implicated in the synchronization of the thalamocortical circuit. Over the past few decades, the conventional view has been that rhythmic burst firing mediated by T-type channels in both thalamic reticular nuclie (TRN) and thalamocortical (TC) neurons are equally critical in the generation of thalamocortical oscillations during sleep rhythms and spike-wave-discharges (SWDs). This review broadly investigates recent studies indicating that even though both TRN and TC nuclei are required for thalamocortical oscillations, the contributions of T-type channels to TRN and TC neurons are not equal in the genesis of sleep spindles and SWDs. T-type channels in TC neurons are an essential component of SWD generation, whereas the requirement for TRN T-type channels in SWD generation remains controversial at least in the GBL model of absence seizures. Therefore, a deeper understanding of the functional consequences of modulating each T-type channel subtype could guide the development of therapeutic tools for absence seizures while minimizing side effects on physiological thalamocortical oscillations. This article is part of a Special Issue entitled: Calcium channels.
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Affiliation(s)
- Eunji Cheong
- Department of Biotechnology, Translational Research Center for Protein Function Control, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea.
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46
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Francois A, Kerckhove N, Meleine M, Alloui A, Barrere C, Gelot A, Uebele VN, Renger JJ, Eschalier A, Ardid D, Bourinet E. State-dependent properties of a new T-type calcium channel blocker enhance Ca(V)3.2 selectivity and support analgesic effects. Pain 2012; 154:283-293. [PMID: 23257507 DOI: 10.1016/j.pain.2012.10.023] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Revised: 09/06/2012] [Accepted: 10/30/2012] [Indexed: 01/01/2023]
Abstract
T-type calcium channels encoded by the Ca(V)3.2 isoform are expressed in nociceptive primary afferent neurons where they contribute to hyperalgesia and thus are considered as a potential therapeutic target to treat pathological pain. Here we report that the small organic state-dependent T-type channel antagonist TTA-A2 efficiently inhibits recombinant and native Ca(V)3.2 currents. Although TTA-A2 is a pan Ca(V)3 blocker, it demonstrates a higher potency for Ca(V)3.2 compared to Ca(V)3.1. TTA-A2 selectivity for T-type currents was demonstrated in sensory neurons where it lowered cell excitability uniquely on neurons expressing T-type channels. In vivo pharmacology in Ca(V)3.2 knockout and wild type mice reveal that TTA-A2-mediated antinociception critically depends on Ca(V)3.2 expression. The pathophysiology of irritable bowel syndrome (IBS) was recently demonstrated to involve Ca(V)3.2 in a rat model of this disease. Oral administration of TTA-A2 produced a dose-dependent reduction of hypersensitivity in an IBS model, demonstrating its therapeutic potential for the treatment of pathological pain. Overall, our results suggest that the high potency of TTA-A2 in the depolarized state strengthen its analgesic efficacy and selectivity toward pathological pain syndromes. This characteristic would be beneficial for the development of analgesics targeting T-type channels, in particular for the treatment of pain associated with IBS.
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Affiliation(s)
- Amaury Francois
- Laboratories of Excellence, Ion Channel Science and Therapeutics, Institut de Génomique Fonctionnelle, 141 rue de la Cardonille, 34094 Montpellier, France CNRS UMR5203, Montpellier, France INSERM, U661, Montpellier, France IFR3 Universités Montpellier I & II, Montpellier, France Clermont Université, Université d'Auvergne, Pharmacologie fondamentale et clinique de la douleur, BP 10448, F-63000 Clermont-Ferrand, France Inserm, U 766, F-63001 Clermont-Ferrand, France Merck Research Laboratories, West Point, PA, USA CHU Clermont-Ferrand, Service de Pharmacologie, F-63003 Clermont-Ferrand, France
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Galetin T, Tevoufouet EE, Sandmeyer J, Matthes J, Nguemo F, Hescheler J, Weiergräber M, Schneider T. Pharmacoresistant Cav 2·3 (E-type/R-type) voltage-gated calcium channels influence heart rate dynamics and may contribute to cardiac impulse conduction. Cell Biochem Funct 2012; 31:434-49. [PMID: 23086800 DOI: 10.1002/cbf.2918] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 09/21/2012] [Accepted: 09/24/2012] [Indexed: 11/10/2022]
Abstract
Voltage-gated Ca(2+) channels regulate cardiac automaticity, rhythmicity and excitation-contraction coupling. Whereas L-type (Cav 1·2, Cav 1·3) and T-type (Cav 3·1, Cav 3·2) channels are widely accepted for their functional relevance in the heart, the role of Cav 2·3 Ca(2+) channels expressing R-type currents remains to be elucidated. We have investigated heart rate dynamics in control and Cav 2·3-deficient mice using implantable electrocardiogram radiotelemetry and pharmacological injection experiments. Autonomic block revealed that the intrinsic heart rate does not differ between both genotypes. Systemic administration of isoproterenol resulted in a significant reduction in interbeat interval in both genotypes. It remained unaffected after administering propranolol in Cav 2·3(-|-) mice. Heart rate from isolated hearts as well as atrioventricular conduction for both genotypes differed significantly. Additionally, we identified and analysed the developmental expression of two splice variants, i.e. Cav 2·3c and Cav 2·3e. Using patch clamp technology, R-type currents could be detected in isolated prenatal cardiomyocytes and be related to R-type Ca(2+) channels. Our results indicate that on the systemic level, the pharmacologically inducible heart rate range and heart rate reserve are impaired in Cav 2·3 (-|-) mice. In addition, experiments on Langendorff perfused hearts elucidate differences in basic properties between both genotypes. Thus, Cav 2·3 does not only contribute to the cardiac autonomous nervous system but also to intrinsic rhythm propagation.
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Affiliation(s)
- Thomas Galetin
- Institute of Neurophysiology, University of Köln, Köln, Germany
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48
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Alternative splicing: functional diversity among voltage-gated calcium channels and behavioral consequences. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1522-9. [PMID: 23022282 DOI: 10.1016/j.bbamem.2012.09.018] [Citation(s) in RCA: 92] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Revised: 09/15/2012] [Accepted: 09/19/2012] [Indexed: 12/14/2022]
Abstract
Neuronal voltage-gated calcium channels generate rapid, transient intracellular calcium signals in response to membrane depolarization. Neuronal Ca(V) channels regulate a range of cellular functions and are implicated in a variety of neurological and psychiatric diseases including epilepsy, Parkinson's disease, chronic pain, schizophrenia, and bipolar disorder. Each mammalian Cacna1 gene has the potential to generate tens to thousands of Ca(V) channels by alternative pre-mRNA splicing, a process that adds fine granulation to the pool of Ca(V) channel structures and functions. The precise composition of Ca(V) channel splice isoform mRNAs expressed in each cell are controlled by cell-specific splicing factors. The activity of splicing factors are in turn regulated by molecules that encode various cellular features, including cell-type, activity, metabolic states, developmental state, and other factors. The cellular and behavioral consequences of individual sites of Ca(V) splice isoforms are being elucidated, as are the cell-specific splicing factors that control splice isoform selection. Altered patterns of alternative splicing of Ca(V) pre-mRNAs can alter behavior in subtle but measurable ways, with the potential to influence drug efficacy and disease severity. This article is part of a Special Issue entitled: Calcium channels.
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49
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Modulation of low-voltage-activated T-type Ca²⁺ channels. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:1550-9. [PMID: 22975282 DOI: 10.1016/j.bbamem.2012.08.032] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 08/29/2012] [Accepted: 08/30/2012] [Indexed: 12/16/2022]
Abstract
Low-voltage-activated T-type Ca²⁺ channels contribute to a wide variety of physiological functions, most predominantly in the nervous, cardiovascular and endocrine systems. Studies have documented the roles of T-type channels in sleep, neuropathic pain, absence epilepsy, cell proliferation and cardiovascular function. Importantly, novel aspects of the modulation of T-type channels have been identified over the last few years, providing new insights into their physiological and pathophysiological roles. Although there is substantial literature regarding modulation of native T-type channels, the underlying molecular mechanisms have only recently begun to be addressed. This review focuses on recent evidence that the Ca(v)3 subunits of T-type channels, Ca(v)3.1, Ca(v)3.2 and Ca(v)3.3, are differentially modulated by a multitude of endogenous ligands including anandamide, monocyte chemoattractant protein-1, endostatin, and redox and oxidizing agents. The review also provides an overview of recent knowledge gained concerning downstream pathways involving G-protein-coupled receptors. This article is part of a Special Issue entitled: Calcium channels.
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50
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van Loo KMJ, Schaub C, Pernhorst K, Yaari Y, Beck H, Schoch S, Becker AJ. Transcriptional regulation of T-type calcium channel CaV3.2: bi-directionality by early growth response 1 (Egr1) and repressor element 1 (RE-1) protein-silencing transcription factor (REST). J Biol Chem 2012; 287:15489-501. [PMID: 22431737 DOI: 10.1074/jbc.m111.310763] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The pore-forming Ca(2+) channel subunit Ca(V)3.2 mediates a low voltage-activated (T-type) Ca(2+) current (I(CaT)) that contributes pivotally to neuronal and cardiac pacemaker activity. Despite the importance of tightly regulated Ca(V)3.2 levels, the mechanisms regulating its transcriptional dynamics are not well understood. Here, we have identified two key factors that up- and down-regulate the expression of the gene encoding Ca(V)3.2 (Cacna1h). First, we determined the promoter region and observed several stimulatory and inhibitory clusters. Furthermore, we found binding sites for the transcription factor early growth response 1 (Egr1/Zif268/Krox-24) to be highly overrepresented within the Ca(V)3.2 promoter region. mRNA expression analyses and dual-luciferase promoter assays revealed that the Ca(V)3.2 promoter was strongly activated by Egr1 overexpression in vitro and in vivo. Subsequent chromatin immunoprecipitation assays in NG108-15 cells and mouse hippocampi confirmed specific Egr1 binding to the Ca(V)3.2 promoter. Congruently, whole-cell I(CaT) values were significantly larger after Egr1 overexpression. Intriguingly, Egr1-induced activation of the Ca(V)3.2 promoter was effectively counteracted by the repressor element 1-silencing transcription factor (REST). Thus, Egr1 and REST can bi-directionally regulate Ca(V)3.2 promoter activity and mRNA expression and, hence, the size of I(CaT). This mechanism has critical implications for the regulation of neuronal and cardiac Ca(2+) homeostasis under physiological conditions and in episodic disorders such as arrhythmias and epilepsy.
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Affiliation(s)
- Karen M J van Loo
- Department of Neuropathology, University of Bonn Medical Center, D-53105 Bonn, Germany.
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