1
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Contreras E, Bhoi JD, Sonoda T, Birnbaumer L, Schmidt TM. Melanopsin activates divergent phototransduction pathways in intrinsically photosensitive retinal ganglion cell subtypes. eLife 2023; 12:e80749. [PMID: 37937828 PMCID: PMC10712949 DOI: 10.7554/elife.80749] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Accepted: 11/06/2023] [Indexed: 11/09/2023] Open
Abstract
Melanopsin signaling within intrinsically photosensitive retinal ganglion cell (ipRGC) subtypes impacts a broad range of behaviors from circadian photoentrainment to conscious visual perception. Yet, how melanopsin phototransduction within M1-M6 ipRGC subtypes impacts cellular signaling to drive diverse behaviors is still largely unresolved. The identity of the phototransduction channels in each subtype is key to understanding this central question but has remained controversial. In this study, we resolve two opposing models of M4 phototransduction, demonstrating that hyperpolarization-activated cyclic nucleotide-gated (HCN) channels are dispensable for this process and providing support for a pathway involving melanopsin-dependent potassium channel closure and canonical transient receptor potential (TRPC) channel opening. Surprisingly, we find that HCN channels are likewise dispensable for M2 phototransduction, contradicting the current model. We instead show that M2 phototransduction requires TRPC channels in conjunction with T-type voltage-gated calcium channels, identifying a novel melanopsin phototransduction target. Collectively, this work resolves key discrepancies in our understanding of ipRGC phototransduction pathways in multiple subtypes and adds to mounting evidence that ipRGC subtypes employ diverse phototransduction cascades to fine-tune cellular responses for downstream behaviors.
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Affiliation(s)
- Ely Contreras
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
- Northwestern University Interdisciplinary Biological Sciences Program, Northwestern UniversityEvanstonUnited States
| | - Jacob D Bhoi
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
- Northwestern University Interdepartmental Neuroscience Program, Northwestern UniversityChicagoUnited States
| | - Takuma Sonoda
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
- Northwestern University Interdepartmental Neuroscience Program, Northwestern UniversityChicagoUnited States
| | - Lutz Birnbaumer
- Laboratory of Signal Transduction, National Institute of Environmental Health SciencesDurhamUnited States
- Institute of Biomedical Research (BIOMED), Catholic University of ArgentinaBuenos AiresArgentina
| | - Tiffany M Schmidt
- Department of Neurobiology, Northwestern UniversityEvanstonUnited States
- Department of Ophthalmology, Feinberg School of MedicineChicagoUnited States
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2
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The emergence of genotypic divergence and future precision medicine applications. HANDBOOK OF CLINICAL NEUROLOGY 2023; 192:87-99. [PMID: 36796950 DOI: 10.1016/b978-0-323-85538-9.00013-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Genotypic divergence is a term adapted from population genetics and intimately linked to evolution. We use divergence here to emphasize the differences that set individuals apart in any cohort. The history of genetics is filled with descriptions of genotypic differences, but causal inference of interindividual biological variation has been scarce. We suggest that the practice of precision medicine requires a divergent approach, an approach dependent on the causal interpretation of previous convergent (and preliminary) knowledge in the field. This knowledge has relied on convergent descriptive syndromology (lumping), which has overemphasized a reductionistic gene determinism on the quest of seeking associations without causal understanding. Regulatory variants with small effect and somatic mutations are some of the modifying factors that lead to incomplete penetrance and intrafamilial variable expressivity often observed in apparently monogenic clinical disorders. A truly divergent approach to precision medicine requires splitting, that is, the consideration of different layers of genetic phenomena that interact causally in a nonlinear fashion. This chapter reviews convergences and divergences in genetics and genomics, aiming to discuss what can be causally understood to approximate the as-yet utopian lands of Precision Medicine for patients with neurodegenerative disorders.
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3
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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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4
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Voltage-Gated T-Type Calcium Channel Modulation by Kinases and Phosphatases: The Old Ones, the New Ones, and the Missing Ones. Cells 2023; 12:cells12030461. [PMID: 36766802 PMCID: PMC9913649 DOI: 10.3390/cells12030461] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 01/14/2023] [Accepted: 01/29/2023] [Indexed: 02/04/2023] Open
Abstract
Calcium (Ca2+) can regulate a wide variety of cellular fates, such as proliferation, apoptosis, and autophagy. More importantly, changes in the intracellular Ca2+ level can modulate signaling pathways that control a broad range of physiological as well as pathological cellular events, including those important to cellular excitability, cell cycle, gene-transcription, contraction, cancer progression, etc. Not only intracellular Ca2+ level but the distribution of Ca2+ in the intracellular compartments is also a highly regulated process. For this Ca2+ homeostasis, numerous Ca2+ chelating, storage, and transport mechanisms are required. There are also specialized proteins that are responsible for buffering and transport of Ca2+. T-type Ca2+ channels (TTCCs) are one of those specialized proteins which play a key role in the signal transduction of many excitable and non-excitable cell types. TTCCs are low-voltage activated channels that belong to the family of voltage-gated Ca2+ channels. Over decades, multiple kinases and phosphatases have been shown to modulate the activity of TTCCs, thus playing an indirect role in maintaining cellular physiology. In this review, we provide information on the kinase and phosphatase modulation of TTCC isoforms Cav3.1, Cav3.2, and Cav3.3, which are mostly described for roles unrelated to cellular excitability. We also describe possible potential modulations that are yet to be explored. For example, both mitogen-activated protein kinase and citron kinase show affinity for different TTCC isoforms; however, the effect of such interaction on TTCC current/kinetics has not been studied yet.
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5
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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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Subbamanda YD, Bhargava A. Intercommunication between Voltage-Gated Calcium Channels and Estrogen Receptor/Estrogen Signaling: Insights into Physiological and Pathological Conditions. Cells 2022; 11:cells11233850. [PMID: 36497108 PMCID: PMC9739980 DOI: 10.3390/cells11233850] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/25/2022] [Accepted: 11/28/2022] [Indexed: 12/05/2022] Open
Abstract
Voltage-gated calcium channels (VGCCs) and estrogen receptors are important cellular proteins that have been shown to interact with each other across varied cells and tissues. Estrogen hormone, the ligand for estrogen receptors, can also exert its effects independent of estrogen receptors that collectively constitute non-genomic mechanisms. Here, we provide insights into the VGCC regulation by estrogen and the possible mechanisms involved therein across several cell types. Notably, most of the interaction is described in neuronal and cardiovascular tissues given the importance of VGCCs in these electrically excitable tissues. We describe the modulation of various VGCCs by estrogen known so far in physiological conditions and pathological conditions. We observed that in most in vitro studies higher concentrations of estrogen were used while a handful of in vivo studies used meager concentrations resulting in inhibition or upregulation of VGCCs, respectively. There is a need for more relevant physiological assays to study the regulation of VGCCs by estrogen. Additionally, other interacting receptors and partners need to be identified that may be involved in exerting estrogen receptor-independent effects of estrogen.
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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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Zhu T, Wang Y. T-type Ca 2+ channels play a dual role in modulating the excitability of dorsal root ganglia neurons. Mol Pain 2022; 18:17448069221132224. [PMID: 36163701 PMCID: PMC9536108 DOI: 10.1177/17448069221132224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A subgroup of low-threshold dorsal root ganglia (DRG) neurons discharge action potentials (APs) with an afterdepolarizing potential (ADP). The ADP is formed by T-type Ca2+ currents. It is known that T-type Ca2+ currents contribute to neuropathic pain. However, the change in ADP-firing of injured DRG neurons has not been widely studied yet. Here we applied patch clamp to record ADP-firing and T-type Ca2+ currents in intact and chronically compressed DRG (CCD) neurons and examined T-type Ca2+ channel proteins expression with western blotting. After CCD injury, the incidences of both ADP firing and non-ADP burst firing increased, and T-type Ca2+ channels contributed to both of these firing patterns. The neurons discharging large-amplitude-ADP firing were TTX-insensitive, implying that high-density T-type Ca2+ channels might cooperate with TTX-insensitive Na+ channels to reduce the AP threshold. By contrast, the neurons displaying non-ADP burst firing were TTX-sensitive, implying that low density T-type Ca2+ channels may cooperate with TTX-sensitive Na+ channels to increase AP number. In DRG neurons, T-type Ca2+ currents density varied widely, ranging between 100 pA/pF and 5 pA/pF. After injury, the proportion of DRG neurons with large T-type Ca2+ currents increased in parallel with the increase in the incidence of large-amplitude-ADP firing. And in addition to Cav3.2, Cav3.3 channels are also likely to contribute to low-threshold firing. The data revealed that T-type Ca2+ channels may play a dual role in modulating the injured neurons' high excitability through a cooperative process with Na+ channels, thereby contributing to neuropathic pain.
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Affiliation(s)
- Tong Zhu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Clinical Experimental Center, Xi'an International Medical Center Hospital, Xi'an, China
| | - Yuying Wang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, China.,Key Laboratory of Environment and Genes Related to Diseases, Ministry of Education, 12480Xi'an Jiaotong University, Xi'an, China.,Institute of Neuroscience, Translational Medicine Institute, Xi'an Jiaotong University Health Science Center, Xi'an, China
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9
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Papazoglou A, Arshaad MI, Henseler C, Daubner J, Broich K, Hescheler J, Ehninger D, Haenisch B, Weiergräber M. Ca v3 T-Type Voltage-Gated Ca 2+ Channels and the Amyloidogenic Environment: Pathophysiology and Implications on Pharmacotherapy and Pharmacovigilance. Int J Mol Sci 2022; 23:ijms23073457. [PMID: 35408817 PMCID: PMC8998330 DOI: 10.3390/ijms23073457] [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: 01/23/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 12/07/2022] Open
Abstract
Voltage-gated Ca2+ channels (VGCCs) were reported to play a crucial role in neurotransmitter release, dendritic resonance phenomena and integration, and the regulation of gene expression. In the septohippocampal system, high- and low-voltage-activated (HVA, LVA) Ca2+ channels were shown to be involved in theta genesis, learning, and memory processes. In particular, HVA Cav2.3 R-type and LVA Cav3 T-type Ca2+ channels are expressed in the medial septum-diagonal band of Broca (MS-DBB), hippocampal interneurons, and pyramidal cells, and ablation of both channels was proven to severely modulate theta activity. Importantly, Cav3 Ca2+ channels contribute to rebound burst firing in septal interneurons. Consequently, functional impairment of T-type Ca2+ channels, e.g., in null mutant mouse models, caused tonic disinhibition of the septohippocampal pathway and subsequent enhancement of hippocampal theta activity. In addition, impairment of GABA A/B receptor transcription, trafficking, and membrane translocation was observed within the septohippocampal system. Given the recent findings that amyloid precursor protein (APP) forms complexes with GABA B receptors (GBRs), it is hypothesized that T-type Ca2+ current reduction, decrease in GABA receptors, and APP destabilization generate complex functional interdependence that can constitute a sophisticated proamyloidogenic environment, which could be of potential relevance in the etiopathogenesis of Alzheimer’s disease (AD). The age-related downregulation of T-type Ca2+ channels in humans goes together with increased Aβ levels that could further inhibit T-type channels and aggravate the proamyloidogenic environment. The mechanistic model presented here sheds new light on recent reports about the potential risks of T-type Ca2+ channel blockers (CCBs) in dementia, as observed upon antiepileptic drug application in the elderly.
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Affiliation(s)
- Anna Papazoglou
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Muhammad Imran Arshaad
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Christina Henseler
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Johanna Daubner
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
| | - Karl Broich
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
| | - Jürgen Hescheler
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
| | - Dan Ehninger
- Translational Biogerontology, German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany;
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
| | - Britta Haenisch
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- German Center for Neurodegenerative Diseases (Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE), Venusberg-Campus 1/99, 53127 Bonn, Germany
- Center for Translational Medicine, Medical Faculty, University of Bonn, 53113 Bonn, Germany
| | - Marco Weiergräber
- Experimental Neuropsychopharmacology, Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (A.P.); (M.I.A.); (C.H.); (J.D.)
- Federal Institute for Drugs and Medical Devices (Bundesinstitut für Arzneimittel und Medizinprodukte, BfArM), Kurt-Georg-Kiesinger-Allee 3, 53175 Bonn, Germany; (K.B.); (B.H.)
- Faculty of Medicine, Institute of Neurophysiology, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany;
- Center of Physiology and Pathophysiology, Faculty of Medicine, University of Cologne, Robert-Koch-Str. 39, 50931 Cologne, Germany
- Correspondence: ; Tel.: +49-228-99307-4358
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10
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Reticular Basement Membrane Thickness Is Associated with Growth- and Fibrosis-Promoting Airway Transcriptome Profile-Study in Asthma Patients. Int J Mol Sci 2021; 22:ijms22030998. [PMID: 33498209 PMCID: PMC7863966 DOI: 10.3390/ijms22030998] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 01/15/2021] [Accepted: 01/17/2021] [Indexed: 12/24/2022] Open
Abstract
Airway remodeling in asthma is characterized by reticular basement membrane (RBM) thickening, likely related to epithelial structural and functional changes. Gene expression profiling of the airway epithelium might identify genes involved in bronchial structural alterations. We analyzed bronchial wall geometry (computed tomography (CT)), RBM thickness (histology), and the bronchial epithelium transcriptome profile (gene expression array) in moderate to severe persistent (n = 21) vs. no persistent (n = 19) airflow limitation asthmatics. RBM thickness was similar in the two studied subgroups. Among the genes associated with increased RBM thickness, the most essential were those engaged in cell activation, proliferation, and growth (e.g., CDK20, TACC2, ORC5, and NEK5) and inhibiting apoptosis (e.g., higher mRNA expression of RFN34, BIRC3, NAA16, and lower of RNF13, MRPL37, CACNA1G). Additionally, RBM thickness correlated with the expression of genes encoding extracellular matrix (ECM) components (LAMA3, USH2A), involved in ECM remodeling (LTBP1), neovascularization (FGD5, HPRT1), nerve functioning (TPH1, PCDHGC4), oxidative stress adaptation (RIT1, HSP90AB1), epigenetic modifications (OLMALINC, DNMT3A), and the innate immune response (STAP1, OAS2). Cluster analysis revealed that genes linked with RBM thickness were also related to thicker bronchial walls in CT. Our study suggests that the pro-fibrotic profile in the airway epithelial cell transcriptome is associated with a thicker RBM, and thus, may contribute to asthma airway remodeling.
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11
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Novel Missense CACNA1G Mutations Associated with Infantile-Onset Developmental and Epileptic Encephalopathy. Int J Mol Sci 2020; 21:ijms21176333. [PMID: 32878331 PMCID: PMC7503748 DOI: 10.3390/ijms21176333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/29/2020] [Accepted: 08/29/2020] [Indexed: 11/17/2022] Open
Abstract
The CACNA1G gene encodes the low-voltage-activated Cav3.1 channel, which is expressed in various areas of the CNS, including the cerebellum. We studied two missense CACNA1G variants, p.L208P and p.L909F, and evaluated the relationships between the severity of Cav3.1 dysfunction and the clinical phenotype. The presentation was of a developmental and epileptic encephalopathy without evident cerebellar atrophy. Both patients exhibited axial hypotonia, developmental delay, and severe to profound cognitive impairment. The patient with the L909F mutation had initially refractory seizures and cerebellar ataxia, whereas the L208P patient had seizures only transiently but was overall more severely affected. In transfected mammalian cells, we determined the biophysical characteristics of L208P and L909F variants, relative to the wild-type channel and a previously reported gain-of-function Cav3.1 variant. The L208P mutation shifted the activation and inactivation curves to the hyperpolarized direction, slowed the kinetics of inactivation and deactivation, and reduced the availability of Ca2+ current during repetitive stimuli. The L909F mutation impacted channel function less severely, resulting in a hyperpolarizing shift of the activation curve and slower deactivation. These data suggest that L909F results in gain-of-function, whereas L208P exhibits mixed gain-of-function and loss-of-function effects due to opposing changes in the biophysical properties. Our study expands the clinical spectrum associated with CACNA1G mutations, corroborating further the causal association with distinct complex phenotypes.
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12
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Lory P, Nicole S, Monteil A. Neuronal Cav3 channelopathies: recent progress and perspectives. Pflugers Arch 2020; 472:831-844. [PMID: 32638069 PMCID: PMC7351805 DOI: 10.1007/s00424-020-02429-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/08/2020] [Accepted: 06/26/2020] [Indexed: 12/22/2022]
Abstract
T-type, low-voltage activated, calcium channels, now designated Cav3 channels, are involved in a wide variety of physiological functions, especially in nervous systems. Their unique electrophysiological properties allow them to finely regulate neuronal excitability and to contribute to sensory processing, sleep, and hormone and neurotransmitter release. In the last two decades, genetic studies, including exploration of knock-out mouse models, have greatly contributed to elucidate the role of Cav3 channels in normal physiology, their regulation, and their implication in diseases. Mutations in genes encoding Cav3 channels (CACNA1G, CACNA1H, and CACNA1I) have been linked to a variety of neurodevelopmental, neurological, and psychiatric diseases designated here as neuronal Cav3 channelopathies. In this review, we describe and discuss the clinical findings and supporting in vitro and in vivo studies of the mutant channels, with a focus on de novo, gain-of-function missense mutations recently discovered in CACNA1G and CACNA1H. Overall, the studies of the Cav3 channelopathies help deciphering the pathogenic mechanisms of corresponding diseases and better delineate the properties and physiological roles Cav3 channels.
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Affiliation(s)
- Philippe Lory
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France. .,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France.
| | - Sophie Nicole
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, CNRS, INSERM, University Montpellier, 141, rue de la Cardonille, 34094, Montpellier, France.,LabEx 'Ion Channel Science and Therapeutics' (ICST), Montpellier, France
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13
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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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14
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Kushner J, Ferrer X, Marx SO. Roles and Regulation of Voltage-gated Calcium Channels in Arrhythmias. J Innov Card Rhythm Manag 2019; 10:3874-3880. [PMID: 32494407 PMCID: PMC7252866 DOI: 10.19102/icrm.2019.101006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 03/04/2019] [Indexed: 12/25/2022] Open
Abstract
Calcium flowing through voltage-dependent calcium channels into cardiomyocytes mediates excitation–contraction coupling, controls action-potential duration and automaticity in nodal cells, and regulates gene expression. Proper surface targeting and basal and hormonal regulation of calcium channels are vital for normal cardiac physiology. In this review, we discuss the roles of voltage-gated calcium channels in the heart and the mechanisms by which these channels are regulated by physiological signaling pathways in health and disease.
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Affiliation(s)
- Jared Kushner
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Xavier Ferrer
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Steven O Marx
- Division of Cardiology, Department of Medicine, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA
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15
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Zhang M, Zou B, Gunaratna MJ, Weerasekara S, Tong Z, Nguyen TDT, Koldas S, Cao WS, Pascual C, Xie XS, Hua DH. SYNTHESIS OF 1,3,4-OXADIAZOLES AS SELECTIVE T-TYPE CALCIUM CHANNEL INHIBITORS. HETEROCYCLES 2019; 101:145-164. [PMID: 32773946 PMCID: PMC7413294 DOI: 10.3987/com-19-s(f)5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Neuropathic pain, epilepsy, insomnia, and tremor disorder may arrive from an increase of intracellular Ca2+ concentration through a dysfunction of T-type Ca2+ channels. Thus, T-type calcium channels could be a target in drug discovery for the treatments of neuropathic pain and epilepsy. From rational drug design approach, a group of 2,5-disubstituted 1,3,4-oxadiazole molecules was synthesized and their selective T-type channel inhibitions were evaluated. The synthetic strategy consists of a short sequence of three reactions: (i) condensation of thiosemicarbazide with acid chlorides; (ii) ring closing by 1,3-dibromo-5,5- dimethylhydantoin; and (iii) coupling with various acid chlorides. 5-Chloro-N-(5- phenyl-1,3,4-oxadiazol-2-yl)thiophene-2-carboxamide (11) was found to selectively inhibit T-type Ca2+ channel over Na+ and K+ channels in mouse dorsal root ganglion neurons and/or human embryonic kidney (HEK)-293 cells and to suppress seizure-induced death in mouse model. Consequently, compound 11 is a useful probe for investigation of physiologic and pathophysiologic roles of the T-channel, and provides a basis to develop a novel therapeutic to treat chronic neuropathic and inflammatory pains.
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Affiliation(s)
- Man Zhang
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - Bende Zou
- AfaSci Research Laboratories, Redwood City, CA 94063, U. S. A
| | - Medha J Gunaratna
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - Sahani Weerasekara
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - Zongbo Tong
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - Thi D T Nguyen
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - Serkan Koldas
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
| | - William S Cao
- AfaSci Research Laboratories, Redwood City, CA 94063, U. S. A
| | - Conrado Pascual
- AfaSci Research Laboratories, Redwood City, CA 94063, U. S. A
| | | | - Duy H Hua
- Department of Chemistry, Kansas State University, 1212 Mid Campus Drive, Manhattan, KS 66506, U. S. A
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16
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Qu YS, Lazzerini PE, Capecchi PL, Laghi-Pasini F, El Sherif N, Boutjdir M. Autoimmune Calcium Channelopathies and Cardiac Electrical Abnormalities. Front Cardiovasc Med 2019; 6:54. [PMID: 31119135 PMCID: PMC6507622 DOI: 10.3389/fcvm.2019.00054] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 04/16/2019] [Indexed: 12/24/2022] Open
Abstract
Patients with autoimmune diseases are at increased risk for developing cardiovascular diseases, and abnormal electrocardiographic findings are common. Voltage-gated calcium channels play a major role in the cardiovascular system and regulate cardiac excitability and contractility. Particularly, by virtue of their localization and expression in the heart, calcium channels modulate pace making at the sinus node, conduction at the atrioventricular node and cardiac repolarization in the working myocardium. Consequently, emerging evidence suggests that calcium channels are targets to autoantibodies in autoimmune diseases. Autoimmune-associated cardiac calcium channelopathies have been recognized in both sinus node dysfunction atrioventricular block in patients positive for anti-Ro/La antibodies, and ventricular arrhythmias in patients with dilated cardiomyopathy. In this review, we discuss mechanisms of autoimmune-associated calcium channelopathies and their relationship with the development of cardiac electrical abnormalities.
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Affiliation(s)
- Yongxia Sarah Qu
- Department of Cardiology, New York Presbyterian Brooklyn Methodist Hospital, Brooklyn, NY, United States.,VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States
| | - Pietro Enea Lazzerini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Pier Leopoldo Capecchi
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Franco Laghi-Pasini
- Department of Medical Sciences, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Nabil El Sherif
- VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States
| | - Mohamed Boutjdir
- VA New York Harbor Healthcare System and State University of New York Downstate Medical Center, Brooklyn, NY, United States.,NYU School of Medicine, New York, NY, United States
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17
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Visa A, Shaikh S, Alza L, Herreros J, Cantí C. The Hard-To-Close Window of T-Type Calcium Channels. Trends Mol Med 2019; 25:571-584. [PMID: 31031178 DOI: 10.1016/j.molmed.2019.03.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 03/04/2019] [Accepted: 03/06/2019] [Indexed: 01/03/2023]
Abstract
T-Type calcium channels (TTCCs) are key regulators of membrane excitability, which is the reason why TTCC pharmacology is subject to intensive research in the neurological and cardiovascular fields. TTCCs also play a role in cancer physiology, and pharmacological blockers such as tetralols and dihydroquinazolines (DHQs) reduce the viability of cancer cells in vitro and slow tumor growth in murine xenografts. However, the available compounds are better suited to blocking TTCCs in excitable membranes rather than TTCCs contributing window currents at steady potentials. Consistently, tetralols and dihydroquinazolines exhibit cytostatic/cytotoxic activities at higher concentrations than those required for TTCC blockade, which may involve off-target effects. Gene silencing experiments highlight the targetability of TTCCs, but further pharmacological research is required for TTCC blockade to become a chemotherapeutic option.
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Affiliation(s)
- Anna Visa
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Soni Shaikh
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Lía Alza
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Judit Herreros
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain
| | - Carles Cantí
- Laboratory of Calcium Cell Signaling, IRBLleida-Universitat de Lleida, Rovira Roure, 80, 25198-Lleida, Spain.
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18
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Wang D, Ragnarsson L, Lewis RJ. T-type Calcium Channels in Health and Disease. Curr Med Chem 2018; 27:3098-3122. [PMID: 30277145 DOI: 10.2174/0929867325666181001112821] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 08/28/2018] [Accepted: 08/30/2018] [Indexed: 12/12/2022]
Abstract
Low Voltage-Activated (LVA) T-type calcium channels are characterized by transient current and Low Threshold Spikes (LTS) that trigger neuronal firing and oscillatory behavior. Combined with their preferential localization in dendrites and their specific "window current", T-type calcium channels are considered to be key players in signal amplification and synaptic integration. Assisted by the emerging pharmacological tools, the structural determinants of channel gating and kinetics, as well as novel physiological and pathological functions of T-type calcium channels, are being uncovered. In this review, we provide an overview of structural determinants in T-type calcium channels, their involvement in disorders and diseases, the development of novel channel modulators, as well as Structure-Activity Relationship (SAR) studies that lead to rational drug design.
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Affiliation(s)
- Dan Wang
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Lotten Ragnarsson
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
| | - Richard J Lewis
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, the University of Queensland, Brisbane Qld 4072, Australia
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19
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Yang HK, Son WS, Lim KS, Kim GH, Lim EJ, Gadhe CG, Lee JY, Jeong KS, Lim SM, Pae AN. Synthesis and biological evaluation of pyrrolidine-based T-type calcium channel inhibitors for the treatment of neuropathic pain. J Enzyme Inhib Med Chem 2018; 33:1460-1471. [PMID: 30231778 PMCID: PMC6151954 DOI: 10.1080/14756366.2018.1513926] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
The treatment of neuropathic pain is one of the urgent unmet medical needs and T-type calcium channels are promising therapeutic targets for neuropathic pain. Several potent T-type channel inhibitors showed promising in vivo efficacy in neuropathic pain animal models and are being investigated in clinical trials. Herein we report development of novel pyrrolidine-based T-type calcium channel inhibitors by pharmacophore mapping and structural hybridisation followed by evaluation of their Cav3.1 and Cav3.2 channel inhibitory activities. Among potent inhibitors against both Cav3.1 and Cav3.2 channels, a promising compound 20n based on in vitro ADME properties displayed satisfactory plasma and brain exposure in rats according to in vivo pharmacokinetic studies. We further demonstrated that 20n effectively improved the symptoms of neuropathic pain in both SNL and STZ neuropathic pain animal models, suggesting modulation of T-type calcium channels can be a promising therapeutic strategy for the treatment of neuropathic pain.
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Affiliation(s)
- Hak Kyun Yang
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea
| | - Woo Seung Son
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea.,b Department of Chemistry , Yonsei University , Seoul , Republic of Korea
| | - Keon Seung Lim
- c 1ST Biotherapeutics Inc. , Seongnam , Gyeonggi-do , Republic of Korea
| | - Gun Hee Kim
- d Research Institute for Basic Sciences and Department of Chemistry, College of Sciences , Kyung Hee University , Seoul , Republic of Korea
| | - Eun Jeong Lim
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea
| | - Changdev G Gadhe
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea
| | - Jae Yeol Lee
- d Research Institute for Basic Sciences and Department of Chemistry, College of Sciences , Kyung Hee University , Seoul , Republic of Korea
| | - Kyu-Sung Jeong
- b Department of Chemistry , Yonsei University , Seoul , Republic of Korea
| | - Sang Min Lim
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea.,e Division of Bio-Medical Science and Technology , Korea University of Science and Technology , Daejon , Republic of Korea
| | - Ae Nim Pae
- a Convergence Research Center for Diagnosis, Treatment and Care System of Dementia , Korea Institute of Science and Technology , Seoul , Republic of Korea.,f Division of Bio-Medical Science & Technology, KIST School , Korea University of Science and Technology , Seoul , Republic of Korea
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20
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Pohl A, Wachter A, Hatam N, Leonhardt S. A computational model of a human single sinoatrial node cell. Biomed Phys Eng Express 2016; 2:035006. [PMID: 37608504 DOI: 10.1088/2057-1976/2/3/035006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Accepted: 03/18/2016] [Indexed: 02/07/2023]
Abstract
For the investigation of the spontaneous rhythmical activity response in the application of cardiac neuromodulation, we formulated a human sinoatrial node (SAN) cell model. With the aim of decreasing elevated heart rate (HR), we want to establish a hardware-in-the-loop system including this model for the analysis of optimal stimulation patterns of the neurostimulation system. Base model structures are adopted from rabbit SAN cell models available in literature and conveyed with Hodgkin-Huxley-type model equations describing the complex time and voltage dependent activation and deactivation processes of individual ion channels. The resulting model consists of 15 currents which are currently known to be responsible for the generation of the membrane action potential (AP). The model reproduces AP frequencies equivalent to those measured in isolated human SAN cells with a resulting HR of 71.8 bpm. Model validation via simulation of the inhibitory effect of ivabradine showed accordance with experimental results obtained in human studies. Furthermore, we could validate the model in regard to its HR effects upon parasympathetic stimulation with results obtained in a human trial study.
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Affiliation(s)
- A Pohl
- Philips Chair for Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, D-52074 Aachen, Germany
- Department of Cardiovascular and Thoracic Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, D-52074 Aachen, Germany
| | - A Wachter
- Department of Medical Statistics, University Medical Center Göttingen, Humboldtallee 32, D-37073 Göttingen, Germany
| | - N Hatam
- Department of Cardiovascular and Thoracic Surgery, RWTH Aachen University Hospital, Pauwelsstr. 30, D-52074 Aachen, Germany
| | - S Leonhardt
- Philips Chair for Medical Information Technology, RWTH Aachen University, Pauwelsstr. 20, D-52074 Aachen, Germany
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21
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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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22
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Byun JS, Sohn JM, Leem DG, Park B, Nam JH, Shin DH, Shin JS, Kim HJ, Lee KT, Lee JY. In vitro synergistic anticancer activity of the combination of T-type calcium channel blocker and chemotherapeutic agent in A549 cells. Bioorg Med Chem Lett 2015; 26:1073-1079. [PMID: 26739776 DOI: 10.1016/j.bmcl.2015.12.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Revised: 11/10/2015] [Accepted: 12/04/2015] [Indexed: 01/15/2023]
Abstract
As a result of our continuous research, new 3,4-dihydroquinazoline derivative containing ureido group, KCP10043F was synthesized and evaluated for T-type Ca(2+) channel (Cav3.1) blockade, cytotoxicity, and cell cycle arrest against human non-small cell lung (A549) cells. KCP10043F showed both weaker T-type Ca(2+) channel blocking activity and less cytotoxicity against A549 cells than parent compound KYS05090S [4-(benzylcarbamoylmethyl)-3-(4-biphenylyl)-2-(N,N',N'-trimethyl-1,5-pentanediamino)-3,4-dihydroquinazoline 2 hydrochloride], but it exhibited more potent G1-phase arrest than KYS05090S in A549 cells. This was found to be accompanied by the downregulations of cyclin-dependent kinase (CDK) 2, CDK4, CDK6, cyclin D2, cyclin D3, and cyclin E at the protein levels. However, p27(KIP1) as a CDK inhibitor was gradually upregulated at the protein levels and increased recruitment to CDK2, CDK4 and CDK6 after KCP10043F treatment. Based on the strong G1-phase cell cycle arrest of KCP10043F in A549 cells, the combination of KCP10043F with etoposide (or cisplatin) resulted in a synergistic cell death (combination index=0.2-0.8) via the induction of apoptosis compared with either agent alone. Taken together with these overall results and the favorable in vitro ADME (absorption, distribution, metabolism, and excretion) profiles of KCP10043F, therefore, it could be used as a potential agent for the combination therapy on human lung cancer.
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Affiliation(s)
- Joon Seok Byun
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Joo Mi Sohn
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Dong Gyu Leem
- Department of Life and Nanopharmaceutical Science, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Byeongyeon Park
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Ji Hye Nam
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Dong Hyun Shin
- Department of Life and Nanopharmaceutical Science, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Ji Sun Shin
- Department of Life and Nanopharmaceutical Science, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea
| | - Hyoung Ja Kim
- Molecular Recognition Research Center, Future Convergence Research Division, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Kyung-Tae Lee
- Department of Life and Nanopharmaceutical Science, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea.
| | - Jae Yeol Lee
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, 26 Kyungheedae-ro, Dongdaemun-gu, Seoul 02447, Republic of Korea.
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23
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Coutelier M, Blesneac I, Monteil A, Monin ML, Ando K, Mundwiller E, Brusco A, Le Ber I, Anheim M, Castrioto A, Duyckaerts C, Brice A, Durr A, Lory P, Stevanin G. A Recurrent Mutation in CACNA1G Alters Cav3.1 T-Type Calcium-Channel Conduction and Causes Autosomal-Dominant Cerebellar Ataxia. Am J Hum Genet 2015; 97:726-37. [PMID: 26456284 DOI: 10.1016/j.ajhg.2015.09.007] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 09/18/2015] [Indexed: 12/20/2022] Open
Abstract
Hereditary cerebellar ataxias (CAs) are neurodegenerative disorders clinically characterized by a cerebellar syndrome, often accompanied by other neurological or non-neurological signs. All transmission modes have been described. In autosomal-dominant CA (ADCA), mutations in more than 30 genes are implicated, but the molecular diagnosis remains unknown in about 40% of cases. Implication of ion channels has long been an ongoing topic in the genetics of CA, and mutations in several channel genes have been recently connected to ADCA. In a large family affected by ADCA and mild pyramidal signs, we searched for the causative variant by combining linkage analysis and whole-exome sequencing. In CACNA1G, we identified a c.5144G>A mutation, causing an arginine-to-histidine (p.Arg1715His) change in the voltage sensor S4 segment of the T-type channel protein Cav3.1. Two out of 479 index subjects screened subsequently harbored the same mutation. We performed electrophysiological experiments in HEK293T cells to compare the properties of the p.Arg1715His and wild-type Cav3.1 channels. The current-voltage and the steady-state activation curves of the p.Arg1715His channel were shifted positively, whereas the inactivation curve had a higher slope factor. Computer modeling in deep cerebellar nuclei (DCN) neurons suggested that the mutation results in decreased neuronal excitability. Taken together, these data establish CACNA1G, which is highly expressed in the cerebellum, as a gene whose mutations can cause ADCA. This is consistent with the neuropathological examination, which showed severe Purkinje cell loss. Our study further extends our knowledge of the link between calcium channelopathies and CAs.
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24
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The Wnt11 Signaling Pathway in Potential Cellular EMT and Osteochondral Differentiation Progression in Nephrolithiasis Formation. Int J Mol Sci 2015; 16:16313-29. [PMID: 26193266 PMCID: PMC4519952 DOI: 10.3390/ijms160716313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/22/2015] [Accepted: 07/07/2015] [Indexed: 11/17/2022] Open
Abstract
The molecular events leading to nephrolithiasis are extremely complex. Previous studies demonstrated that calcium and transforming growth factor-β1 (TGF-β1) may participate in the pathogenesis of stone formation, but the explicit mechanism has not been defined. Using a self-created genetic hypercalciuric stone-forming (GHS) rat model, we observed that the increased level of serous/uric TGF-β1 and elevated intracellular calcium in primary renal tubular epithelial cells (PRECs) was associated with nephrolithiasis progression in vivo. In the setting of high calcium plus high TGF-β1 in vitro, PRECs showed great potential epithelial to mesenchymal transition (EMT) progression and osteochondral differentiation properties, representing the multifarious increased mesenchymal and osteochondral phenotypes (Zeb1, Snail1, Col2A1, OPN, Sox9, Runx2) and decreased epithelial phenotypes (E-cadherin, CK19) bythe detection of mRNAs and corresponding proteins. Moreover, TGF-β-dependent Wnt11 knockdown and L-type Ca2+ channel blocker could greatly reverse EMT progression and osteochondral differentiation in PRECs. TGF-β1 alone could effectively promote EMT, but it had no effect on osteochondral differentiation in NRK cells (Rat kidney epithelial cell line). Stimulation with Ca2+ alone did not accelerate differentiation of NRK. Co-incubation of extracellular Ca2+ and TGF-β1 synergistically promotes EMT and osteochondral differentiation in NRK control cells. Our data supplied a novel view that the pathogenesis of calcium stone development may be associated with synergic effects of TGF-β1 and Ca2+, which promote EMT and osteochondral differentiation via Wnt11 and the L-type calcium channel.
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Voltage-gated calcium channels: Determinants of channel function and modulation by inorganic cations. Prog Neurobiol 2015; 129:1-36. [PMID: 25817891 DOI: 10.1016/j.pneurobio.2014.12.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 12/15/2014] [Accepted: 12/27/2014] [Indexed: 11/20/2022]
Abstract
Voltage-gated calcium channels (VGCCs) represent a key link between electrical signals and non-electrical processes, such as contraction, secretion and transcription. Evolved to achieve high rates of Ca(2+)-selective flux, they possess an elaborate mechanism for selection of Ca(2+) over foreign ions. It has been convincingly linked to competitive binding in the pore, but the fundamental question of how this is reconcilable with high rates of Ca(2+) transfer remains unanswered. By virtue of their similarity to Ca(2+), polyvalent cations can interfere with the function of VGCCs and have proven instrumental in probing the mechanisms underlying selective permeation. Recent emergence of crystallographic data on a set of Ca(2+)-selective model channels provides a structural framework for permeation in VGCCs, and warrants a reconsideration of their diverse modulation by polyvalent cations, which can be roughly separated into three general mechanisms: (I) long-range interactions with charged regions on the surface, affecting the local potential sensed by the channel or influencing voltage-sensor movement by repulsive forces (electrostatic effects), (II) short-range interactions with sites in the ion-conducting pathway, leading to physical obstruction of the channel (pore block), and in some cases (III) short-range interactions with extracellular binding sites, leading to non-electrostatic modifications of channel gating (allosteric effects). These effects, together with the underlying molecular modifications, provide valuable insights into the function of VGCCs, and have important physiological and pathophysiological implications. Allosteric suppression of some of the pore-forming Cavα1-subunits (Cav2.3, Cav3.2) by Zn(2+) and Cu(2+) may play a major role for the regulation of excitability by endogenous transition metal ions. The fact that these ions can often traverse VGCCs can contribute to the detrimental intracellular accumulation of metal ions following excessive release of endogenous Cu(2+) and Zn(2+) or exposure to non-physiological toxic metal ions.
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Jin X, Muntean BS, Aal-Aaboda MS, Duan Q, Zhou J, Nauli SM. L-type calcium channel modulates cystic kidney phenotype. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1518-26. [PMID: 24925129 DOI: 10.1016/j.bbadis.2014.06.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Revised: 05/19/2014] [Accepted: 06/02/2014] [Indexed: 12/13/2022]
Abstract
In polycystic kidney disease (PKD), abnormal proliferation and genomic instability of renal epithelia have been associated with cyst formation and kidney enlargement. We recently showed that L-type calcium channel (CaV1.2) is localized to primary cilia of epithelial cells. Previous studies have also shown that low intracellular calcium level was associated with the hyperproliferation phenotype in the epithelial cells. However, the relationship between calcium channel and cystic kidney phenotype is largely unknown. In this study, we generated cells with somatic deficient Pkd1 or Pkd2 to examine ciliary CaV1.2 function via lentiviral knockdown or pharmacological verapamil inhibition. Although inhibition of CaV1.2 expression or function did not change division and growth patterns in wild-type epithelium, it led to hyperproliferation and polyploidy in mutant cells. Lack of CaV1.2 in Pkd mutant cells also decreased the intracellular calcium level. This contributed to a decrease in CaM kinase activity, which played a significant role in regulating Akt and Erk signaling pathways. Consistent with our in vitro results, CaV1.2 knockdown in zebrafish and Pkd1 heterozygous mice facilitated the formation of kidney cysts. Larger cysts were developed faster in Pkd1 heterozygous mice with CaV1.2 knockdown. Overall, our findings emphasized the importance of CaV1.2 expression in kidneys with somatic Pkd mutation. We further suggest that CaV1.2 could serve as a modifier gene to cystic kidney phenotype.
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Affiliation(s)
- Xingjian Jin
- Department of Physiology and Pharmacology, The University of Toledo, Toledo, OH, USA
| | - Brian S Muntean
- Department of Medicinal and Biological Chemistry, The University of Toledo, Toledo, OH, USA
| | - Munaf S Aal-Aaboda
- Department of Physiology and Pharmacology, The University of Toledo, Toledo, OH, USA
| | - Qiming Duan
- Department of Biochemistry and Cancer Biology, USA
| | - Jing Zhou
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, MA, USA
| | - Surya M Nauli
- Department of Physiology and Pharmacology, The University of Toledo, Toledo, OH, USA; Department of Medicinal and Biological Chemistry, The University of Toledo, Toledo, OH, USA.
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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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T-type channels in the sino-atrial and atrioventricular pacemaker mechanism. Pflugers Arch 2014; 466:791-9. [DOI: 10.1007/s00424-014-1482-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 02/11/2014] [Accepted: 02/12/2014] [Indexed: 11/26/2022]
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Senatore A, Guan W, Spafford JD. Cav3 T-type channels: regulators for gating, membrane expression, and cation selectivity. Pflugers Arch 2014; 466:645-60. [PMID: 24515291 DOI: 10.1007/s00424-014-1449-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 01/10/2014] [Accepted: 01/12/2014] [Indexed: 12/13/2022]
Abstract
Cav3 T-type channels are low-voltage-gated channels with rapid kinetics that are classified among the calcium-selective Cav1 and Cav2 type channels. Here, we outline the fundamental and unique regulators of T-type channels. An ubiquitous and proximally located "gating brake" works in concert with the voltage-sensor domain and S6 alpha-helical segment from domain II to set the canonical low-threshold and transient gating features of T-type channels. Gene splicing of optional exon 25c (and/or exon 26) in the short III-IV linker provides a developmental switch between modes of activity, such as activating in response to membrane depolarization, to channels requiring hyperpolarization input before being available to activate. Downstream of the gating brake in the I-II linker is a key region for regulating channel expression where alternative splicing patterns correlate with functional diversity of spike patterns, pacemaking rate (especially in the heart), stage of development, and animal size. A small but persistent window conductance depolarizes cells and boosts excitability at rest. T-type channels possess an ion selectivity that can resemble not only the calcium ion exclusive Cav1 and Cav2 channels but also the sodium ion selectivity of Nav1 sodium channels too. Alternative splicing in the extracellular turret of domain II generates highly sodium-permeable channels, which contribute to low-threshold sodium spikes. Cav3 channels are more ubiquitous among multicellular animals and more widespread in tissues than the more brain centric Nav1 sodium channels in invertebrates. Highly sodium-permeant Cav3 channels can functionally replace Nav1 channels in species where they are lacking, such as in Caenorhabditis elegans.
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Affiliation(s)
- A Senatore
- Department of Biology, University of Waterloo, B1-173, Waterloo, ON, N2L 3G1, Canada
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30
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Choi DL, Jang SJ, Cho S, Choi HE, Rim HK, Lee KT, Lee JY. Inhibition of cellular proliferation and induction of apoptosis in human lung adenocarcinoma A549 cells by T-type calcium channel antagonist. Bioorg Med Chem Lett 2014; 24:1565-70. [PMID: 24529871 DOI: 10.1016/j.bmcl.2014.01.071] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2013] [Revised: 01/15/2014] [Accepted: 01/24/2014] [Indexed: 01/15/2023]
Abstract
The anti-proliferative and apoptotic activities of new T-type calcium channel antagonist, 6e (BK10040) on human lung adenocarcinoma A549 cells were investigated. The MTT assay results indicated that BK10040 was cytotoxic against human lung adenocarcinoma (A549) and pancreatic cancer (MiaPaCa2) cells in a dose-dependent manner with IC50 of 2.25 and 0.93μM, respectively, which is ca. 2-fold more potent than lead compound KYS05090 despite of its decreased T-type calcium channel blockade. As a mode of action for cytotoxic effect of BK10040 on lung cancer (A549) cells, this cancer cell death was found to have the typical features of apoptosis, as evidenced by the accumulation of positive cells for annexin V. In addition, BK10040 triggered the activations of caspases 3 and 9, and the cleavages of poly (ADP-ribose) polymerase (PARP). Moreover, the treatment with z-VAD-fmk (a broad spectrum caspase inhibitor) significantly prevented BK10040-induced apoptosis. Based on these results, BK10040 may be used as a potential therapeutic agent for human lung cancer via the potent apoptotic activity.
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Affiliation(s)
- Doo Li Choi
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Sun Jeong Jang
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Sehyeon Cho
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Hye-Eun Choi
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Hong-Kun Rim
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Kyung-Tae Lee
- Department of Life and Nanopharmaceutical Science, College of Pharmacy, Kyung Hee University, Seoul 130-701, Republic of Korea
| | - Jae Yeol Lee
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 130-701, Republic of Korea.
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Role of T-type channels in vasomotor function: team player or chameleon? Pflugers Arch 2014; 466:767-79. [PMID: 24482062 DOI: 10.1007/s00424-013-1430-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2013] [Accepted: 12/19/2013] [Indexed: 01/28/2023]
Abstract
Low-voltage-activated T-type calcium channels play an important role in regulating cellular excitability and are implicated in conditions, such as epilepsy and neuropathic pain. T-type channels, especially Cav3.1 and Cav3.2, are also expressed in the vasculature, although patch clamp studies of isolated vascular smooth muscle cells have in general failed to demonstrate these low-voltage-activated calcium currents. By contrast, the channels which are blocked by T-type channel antagonists are high-voltage activated but distinguishable from their L-type counterparts by their T-type biophysical properties and small negative shifts in activation and inactivation voltages. These changes in T-channel properties may result from vascular-specific expression of splice variants of Cav3 genes, particularly in exon 25/26 of the III-IV linker region. Recent physiological studies suggest that T-type channels make a small contribution to vascular tone at low intraluminal pressures, although the relevance of this contribution is unclear. By contrast, these channels play a larger role in vascular tone of small arterioles, which would be expected to function at lower intra-vascular pressures. Upregulation of T-type channel function following decrease in nitric oxide bioavailability and increase in oxidative stress, which occurs during cardiovascular disease, suggests that a more important role could be played by these channels in pathophysiological situations. The ability of T-type channels to be rapidly recruited to the plasma membrane, coupled with their subtype-specific localisation in signalling microdomains where they could modulate the function of calcium-dependent ion channels and pathways, provides a mechanism for rapid up- and downregulation of vasoconstriction. Future investigation into the molecules which govern these changes may illuminate novel targets for the treatment of conditions such as therapy-resistant hypertension and vasospasm.
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Abstract
The electrical output of neurons relies critically on voltage- and calcium-gated ion channels. The traditional view of ion channels is that they operate independently of each other in the plasma membrane in a manner that could be predicted according to biophysical characteristics of the isolated current. However, there is increasing evidence that channels interact with each other not just functionally but also physically. This is exemplified in the case of Cav3 T-type calcium channels, where new work indicates the ability to form signaling complexes with different types of calcium-gated and even voltage-gated potassium channels. The formation of a Cav3-K complex provides the calcium source required to activate KCa1.1 or KCa3.1 channels and, furthermore, to bestow a calcium-dependent regulation of Kv4 channels via associated KChIP proteins. Here, we review these interactions and discuss their significance in the context of neuronal firing properties.
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Zhang Y, Wang H, Qian Z, Feng B, Zhao X, Jiang X, Tao J. Low-voltage-activated T-type Ca2+ channel inhibitors as new tools in the treatment of glioblastoma: the role of endostatin. Pflugers Arch 2014; 466:811-8. [PMID: 24407946 DOI: 10.1007/s00424-013-1427-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 12/16/2013] [Accepted: 12/18/2013] [Indexed: 11/25/2022]
Abstract
Ca(2+) plays a key role in intracellular signaling and controls various cellular processes such as proliferation, differentiation, cell growth, death, and apoptosis. Aberrant changes in intracellular Ca(2+) levels can promote undesired cell proliferation and migration and are therefore associated with certain tumor types. Many research groups have suggested a potential role for voltage-gated Ca(2+) channels in the regulation of tumor growth and progression, particularly T-type channels due to their unique biophysical properties. T-type channels are expressed in normal tissues throughout the body and in different types of tumors such as breast carcinoma, retinoblastoma, neuroblastoma, and glioma. It has been demonstrated that increased functional expression of the α1 subunit of T-type channels plays a role in the abnormal proliferation of glioblastoma cells. As such, siRNA-mediated knockdown of the expression of the α1 subunit of T-type channels decreases the proliferation of these cells. Moreover, pharmacological blockade of T-type channels significantly decreases tumor growth. In this review, we focus on the use of T-type channel blockers for the potential treatment of cancers, particularly highly proliferative tumors such as glioblastoma. We conclude that T-type channel blockers such as endostatin can serve as a potential therapeutic tool for tumors whose proliferation depends on increased T-type channel expression.
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Affiliation(s)
- Yuan Zhang
- The Special Procurement Ward, Department of Geriatrics & Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, 215004, China
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Lessons from the heart: mirroring electrophysiological characteristics during cardiac development to in vitro differentiation of stem cell derived cardiomyocytes. J Mol Cell Cardiol 2013; 67:12-25. [PMID: 24370890 DOI: 10.1016/j.yjmcc.2013.12.011] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 11/14/2013] [Accepted: 12/13/2013] [Indexed: 01/12/2023]
Abstract
The ability of human pluripotent stem cells (hPSCs) to differentiate into any cell type of the three germ layers makes them a very promising cell source for multiple purposes, including regenerative medicine, drug discovery, and as a model to study disease mechanisms and progression. One of the first specialized cell types to be generated from hPSC was cardiomyocytes (CM), and differentiation protocols have evolved over the years and now allow for robust and large-scale production of hPSC-CM. Still, scientists are struggling to achieve the same, mainly ventricular, phenotype of the hPSC-CM in vitro as their adult counterpart in vivo. In vitro generated cardiomyocytes are generally described as fetal-like rather than adult. In this review, we compare the in vivo development of cardiomyocytes to the in vitro differentiation of hPSC into CM with focus on electrophysiology, structure and contractility. Furthermore, known epigenetic changes underlying the differences between adult human CM and CM differentiated from pluripotent stem cells are described. This should provide the reader with an extensive overview of the current status of human stem cell-derived cardiomyocyte phenotype and function. Additionally, the reader will gain insight into the underlying signaling pathways and mechanisms responsible for cardiomyocyte development.
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35
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Jang SJ, Choi HW, Choi DL, Cho S, Rim HK, Choi HE, Kim KS, Huang M, Rhim H, Lee KT, Lee JY. In vitro cytotoxicity on human ovarian cancer cells by T-type calcium channel blockers. Bioorg Med Chem Lett 2013; 23:6656-62. [PMID: 24220170 DOI: 10.1016/j.bmcl.2013.10.049] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 10/11/2013] [Accepted: 10/23/2013] [Indexed: 01/01/2023]
Abstract
The growth inhibition of human cancer cells via T-type Ca(2+) channel blockade has been well known. Herein, a series of new 3,4-dihydroquinazoline derivatives were synthesized via a brief SAR study on KYS05090 template and evaluated for both T-type Ca(2+) channel (Cav3.1) blockade and cytotoxicity on three human ovarian cancer cells (SK-OV-3, A2780 and A2780-T). Most of compounds except 6i generally exhibited more potent cytotoxicity on SK-OV-3 than mibefradil as a positive control regardless of the degree of T-type channel blockade. In particular, eight compounds (KYS05090, 6a and 6c-6h) showing strong channel blockade exhibited almost equal and more potent cytotoxicity on A2780 when compared to mibefradil. On A2780-T paclitaxel-resistant human ovarian carcinoma, two compounds (KYS05090 and 6d) were 20-fold more active than mibefradil. With respect to cell cycle arrest effect on A2780 and A2780-T cells, KYS05090 induced large proportion of sub-G1 phase in the cell cycle progression of A2780 and A2780-T, meaning the induction of cancer cell death instead of cell cycle arrest via blocking T-type Ca(2+) channel. Among new analogues, compounds 6g and 6h induced cell cycle arrest at G1 phase of A2780 and A2780-T cells in dose-dependent manner and exhibited strong anti-proliferation effects of ovarian cancer cells by blocking T-type Ca(2+) channel. Furthermore, 6g and 6h possessing strong cytotoxic effects could induce apoptosis of A2780 cells, which was detected by confocal micrographs using DAPI staining.
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Affiliation(s)
- Sun Jeong Jang
- Research Institute for Basic Sciences and Department of Chemistry, College of Sciences, Kyung Hee University, Seoul 130-701, Republic of Korea
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Strandberg LS, Cui X, Rath A, Liu J, Silverman ED, Liu X, Siragam V, Ackerley C, Su BB, Yan JY, Capecchi M, Biavati L, Accorroni A, Yuen W, Quattrone F, Lung K, Jaeggi ET, Backx PH, Deber CM, Hamilton RM. Congenital heart block maternal sera autoantibodies target an extracellular epitope on the α1G T-type calcium channel in human fetal hearts. PLoS One 2013; 8:e72668. [PMID: 24039792 PMCID: PMC3767782 DOI: 10.1371/journal.pone.0072668] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 07/17/2013] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Congenital heart block (CHB) is a transplacentally acquired autoimmune disease associated with anti-Ro/SSA and anti-La/SSB maternal autoantibodies and is characterized primarily by atrioventricular (AV) block of the fetal heart. This study aims to investigate whether the T-type calcium channel subunit α1G may be a fetal target of maternal sera autoantibodies in CHB. METHODOLOGY/PRINCIPAL FINDINGS We demonstrate differential mRNA expression of the T-type calcium channel CACNA1G (α1G gene) in the AV junction of human fetal hearts compared to the apex (18-22.6 weeks gestation). Using human fetal hearts (20-22 wks gestation), our immunoprecipitation (IP), Western blot analysis and immunofluorescence (IF) staining results, taken together, demonstrate accessibility of the α1G epitope on the surfaces of cardiomyocytes as well as reactivity of maternal serum from CHB affected pregnancies to the α1G protein. By ELISA we demonstrated maternal sera reactivity to α1G was significantly higher in CHB maternal sera compared to controls, and reactivity was epitope mapped to a peptide designated as p305 (corresponding to aa305-319 of the extracellular loop linking transmembrane segments S5-S6 in α1G repeat I). Maternal sera from CHB affected pregnancies also reacted more weakly to the homologous region (7/15 amino acids conserved) of the α1H channel. Electrophysiology experiments with single-cell patch-clamp also demonstrated effects of CHB maternal sera on T-type current in mouse sinoatrial node (SAN) cells. CONCLUSIONS/SIGNIFICANCE Taken together, these results indicate that CHB maternal sera antibodies readily target an extracellular epitope of α1G T-type calcium channels in human fetal cardiomyocytes. CHB maternal sera also show reactivity for α1H suggesting that autoantibodies can target multiple fetal targets.
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Affiliation(s)
- Linn S. Strandberg
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Xuezhi Cui
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Arianna Rath
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jie Liu
- Departments of Physiology and Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Earl D. Silverman
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Xiaoru Liu
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Vinayakumar Siragam
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cameron Ackerley
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Brenda Bin Su
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Jane Yuqing Yan
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | | | | | - William Yuen
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | | | - Kalvin Lung
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Edgar T. Jaeggi
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Peter H. Backx
- Departments of Physiology and Medicine, University of Toronto, Toronto, Ontario, Canada
- Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Charles M. Deber
- Division of Molecular Structure and Function, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Robert M. Hamilton
- Department of Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada
- * E-mail:
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37
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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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Björling K, Morita H, Olsen MF, Prodan A, Hansen PB, Lory P, Holstein-Rathlou NH, Jensen LJ. Myogenic tone is impaired at low arterial pressure in mice deficient in the low-voltage-activated CaV 3.1 T-type Ca(2+) channel. Acta Physiol (Oxf) 2013; 207:709-20. [PMID: 23356724 DOI: 10.1111/apha.12066] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/27/2012] [Accepted: 01/17/2013] [Indexed: 11/28/2022]
Abstract
AIM Using mice deficient in the CaV 3.1 T-type Ca(2+) channel, the aim of the present study was to elucidate the molecular identity of non-L-type channels involved in vascular tone regulation in mesenteric arteries and arterioles. METHODS We used immunofluorescence microscopy to localize CaV 3.1 channels, patch clamp electrophysiology to test the effects of a putative T-type channel blocker NNC 55-0396 on whole-cell Ca(2+) currents, pressure myography and Ca(2+) imaging to test diameter and Ca(2+) responses of the applied vasoconstrictors, and Q-PCR to check mRNA expression levels of several Ca(2+) handling proteins in wild-type and CaV 3.1(-/-) mice. RESULTS Our data indicated that CaV 3.1 channels are important for the maintenance of myogenic tone at low pressures (40-80 mm Hg), whereas they are not involved in high-voltage-activated Ca(2+) currents, Ca(2+) entry or vasoconstriction to high KCl in mesenteric arteries and arterioles. Furthermore, we show that NNC 55-0396 is not a specific T-type channel inhibitor, as it potently blocks L-type and non-L-type high-voltage-activated Ca(2+) currents in mouse mesenteric vascular smooth muscle cell. CONCLUSION Our data using mice deficient in the CaV 3.1 T-type channel represent new evidence for the involvement of non-L-type channels in arteriolar tone regulation. We showed that CaV 3.1 channels are important for the myogenic tone at low arterial pressure, which is potentially relevant under resting conditions in vivo. Moreover, CaV 3.1 channels are not involved in Ca(2+) entry and vasoconstriction to large depolarization with, for example, high KCl. Finally, we caution against using NNC 55-0396 as a specific T-type channel blocker in native cells expressing high-voltage-activated Ca(2+) channels.
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Affiliation(s)
- K. Björling
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Denmark
| | - H. Morita
- Special Patient Oral Care Unit; Kyushu University Hospital; Fukuoka; Japan
| | - M. F. Olsen
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Denmark
| | - A. Prodan
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Denmark
| | - P. B. Hansen
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense; Denmark
| | - P. Lory
- CNRS; Institut de Génomique Fonctionnelle; Université de Montpellier; France
| | - N.-H. Holstein-Rathlou
- Department of Biomedical Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Denmark
| | - L. J. Jensen
- Department of Veterinary Clinical and Animal Sciences; Faculty of Health and Medical Sciences; University of Copenhagen; Denmark
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Adachi T, Shibata S, Okamoto Y, Sato S, Fujisawa S, Ohba T, Ono K. The mechanism of increased postnatal heart rate and sinoatrial node pacemaker activity in mice. J Physiol Sci 2013; 63:133-46. [PMID: 23288563 PMCID: PMC10717579 DOI: 10.1007/s12576-012-0248-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Accepted: 12/09/2012] [Indexed: 01/26/2023]
Abstract
Heart rate (HR) of mammalian species changes postnatally, i.e., HR of large animals including humans decreases, while HR in small animals such as mice and rats increases. To clarify cellular mechanisms underlying the postnatal HR changes, we performed in vivo HR measurement and electrophysiological analysis on sinoatrial node (SAN) cells in mice. The in vivo HR was ~320 beats min(-1) (bpm) immediately after birth, and increased with age to ~690 bpm at postnatal day 14. Under blockage of autonomic nervous systems, HR remained constant until postnatal day 5 and then increased day by day. The spontaneous beating rate of SAN preparation showed a similar postnatal change. The density of the L-type Ca(2+) current (LCC) was smaller in neonatal SAN cells than in adult cells, accompanied by a positive shift of voltage-dependent activation. Thus, the postnatal increase in HR is caused by both the increased sympathetic influence and the intrinsic activity of SAN cells. The different conductance and kinetics of LCC may be involved in the postnatal increase in pacemaker activity.
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Affiliation(s)
- Takeshi Adachi
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Shigehiro Shibata
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Yosuke Okamoto
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Shinichi Sato
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Susumu Fujisawa
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Takayoshi Ohba
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
| | - Kyoichi Ono
- Department of Cell Physiology, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543 Japan
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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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Senatore A, Spafford JD. Gene transcription and splicing of T-type channels are evolutionarily-conserved strategies for regulating channel expression and gating. PLoS One 2012; 7:e37409. [PMID: 22719839 PMCID: PMC3376122 DOI: 10.1371/journal.pone.0037409] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 04/19/2012] [Indexed: 01/17/2023] Open
Abstract
T-type calcium channels operate within tightly regulated biophysical constraints for supporting rhythmic firing in the brain, heart and secretory organs of invertebrates and vertebrates. The snail T-type gene, LCa(v)3 from Lymnaea stagnalis, possesses alternative, tandem donor splice sites enabling a choice of a large exon 8b (201 aa) or a short exon 25c (9 aa) in cytoplasmic linkers, similar to mammalian homologs. Inclusion of optional 25c exons in the III-IV linker of T-type channels speeds up kinetics and causes hyperpolarizing shifts in both activation and steady-state inactivation of macroscopic currents. The abundant variant lacking exon 25c is the workhorse of embryonic Ca(v)3 channels, whose high density and right-shifted activation and availability curves are expected to increase pace-making and allow the channels to contribute more significantly to cellular excitation in prenatal tissue. Presence of brain-enriched, optional exon 8b conserved with mammalian Ca(v)3.1 and encompassing the proximal half of the I-II linker, imparts a ~50% reduction in total and surface-expressed LCa(v)3 channel protein, which accounts for reduced whole-cell calcium currents of +8b variants in HEK cells. Evolutionarily conserved optional exons in cytoplasmic linkers of Ca(v)3 channels regulate expression (exon 8b) and a battery of biophysical properties (exon 25c) for tuning specialized firing patterns in different tissues and throughout development.
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42
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Hawkins NA, Kearney JA. Confirmation of an epilepsy modifier locus on mouse chromosome 11 and candidate gene analysis by RNA-Seq. GENES BRAIN AND BEHAVIOR 2012; 11:452-60. [PMID: 22471526 DOI: 10.1111/j.1601-183x.2012.00790.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Epilepsy is a neurological disorder affecting approximately 1% of the worldwide population. Mutations in voltage-gated sodium channels have been identified in several monogenic epilepsy syndromes. Over 800 mutations have been identified in the voltage-gated sodium channel genes SCN1A and SCN2A in human epilepsies, including genetic epilepsy with febrile seizures plus (GEFS+) and Dravet syndrome. In GEFS+ families, affected members with the same mutation often display variability in clinical severity of the disease. This suggests that additional genes modify the effect of the primary mutation, resulting in the variable clinical presentation. The Scn2a(Q54) transgenic mouse model has an epilepsy phenotype that varies depending on the genetic strain background. Scn2a(Q54) mice congenic on the C57BL/6J strain exhibit delayed seizure onset and improved survival compared to (C57BL/6J × SJL/J)F1.Q54 mice. Two modifier loci of Scn2a(Q54) seizure susceptibility were mapped and designated Moe1 (modifier of epilepsy) on chromosome (chr) 11 and Moe2 on chr 19. To confirm Moe1 and refine its position, we generated interval-specific congenic lines carrying C57BL/6J-derived chr 11 alleles on the SJL/J strain and refined the map position to 89-104 Mb. We then used RNA-Seq for candidate analysis in the modifier region. C57BL/6J and SJL/J male and female brain RNAs were sequenced, revealing numerous significant transcriptome differences and coding single-nucleotide polymorphisms. Additional consideration of gene function and expression suggested several strong candidate modifier genes, including two voltage-gated calcium channel subunits, Cacna1g and Cacnb1, and the proline and acidic amino acid-rich basic leucine zipper transcription factor, Hlf.
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Affiliation(s)
- N A Hawkins
- Neuroscience Program Division of Genetic Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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Han RX, Kim HR, Diao YF, Lee MG, Jin DI. Detection of early pregnancy-specific proteins in Holstein milk. J Proteomics 2012; 75:3221-9. [PMID: 22484055 DOI: 10.1016/j.jprot.2012.03.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 03/12/2012] [Accepted: 03/18/2012] [Indexed: 10/28/2022]
Abstract
Bovine pregnancy is commonly diagnosed by rectal palpation or ultrasonography and changes in progesterone concentration. To determine a simpler and less expensive diagnostic method, we sought to identify early pregnancy-specific proteins in bovine milk by comparing samples collected from pregnant and non-pregnant Holstein cattle. Of the 600-700 protein spots visible on 2-DE gel images, 39 were differentially expressed in milk from pregnant and non-pregnant cattle. Antibodies generated against synthetic peptides of milk whey proteins expressed specifically during pregnancy were used to confirm protein expression patterns. Western blot analysis showed that the levels of expression of lactoferrin (lactotransferrin) and alpha1G T-type calcium channel subunit (alpha-1G) were higher in samples from pregnant than non-pregnant cattle. These findings suggest that assays for pregnancy-specific milk proteins may be used to diagnose pregnancy in cattle.
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Affiliation(s)
- Rong Xun Han
- Department of Animal Science & Biotechnology, Research Center for Transgenic and Cloned Pigs, Chungnam National University, Daejeon, South Korea
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44
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Chevalier M, Gilbert G, Lory P, Marthan R, Quignard JF, Savineau JP. Dehydroepiandrosterone (DHEA) inhibits voltage-gated T-type calcium channels. Biochem Pharmacol 2012; 83:1530-9. [PMID: 22391268 DOI: 10.1016/j.bcp.2012.02.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2012] [Revised: 02/24/2012] [Accepted: 02/24/2012] [Indexed: 01/22/2023]
Abstract
BACKGROUND AND PURPOSE Dehydroepiandrosterone (DHEA) and its sulfated form, DHEAS, are the most abundant steroid hormones in the mammalian blood flow. DHEA may have beneficial effects in various pathophysiological conditions such as cardiovascular diseases or deterioration of the sense of well-being. However to date, the cellular mechanism underlying DHEA action remains elusive and may involve ion channel modulation. In this study, we have characterized the effect of DHEA on T-type voltage-activated calcium channels (T-channels), which are involved in several cardiovascular and neuronal diseases. KEY RESULTS Using the whole-cell patch-clamp technique, we demonstrate that DHEA inhibits the three recombinant T-channels (Ca(V)3.1, Ca(V)3.2 and Ca(V)3.3) expressed in NG108-15 cell line, as well as native T-channels in pulmonary artery smooth muscle cells. This effect of DHEA is both concentration (IC(50) between 2 and 7μM) and voltage-dependent and results in a significant shift of the steady-state inactivation curves toward hyperpolarized potentials. Consequently, DHEA reduces window T-current and inhibits membrane potential oscillations induced by Ca(V)3 channels. DHEA inhibition is not dependent on the activation of nuclear androgen or estrogen receptors and implicates a PTX-sensitive Gi protein pathway. Functionally, DHEA and the T-type inhibitor NNC 55-0396 inhibited KCl-induced contraction of pulmonary artery rings and their effect was not cumulative. CONCLUSIONS Altogether, the present data demonstrate that DHEA inhibits T-channels by a Gi protein dependent pathway. DHEA-induced alteration in T-channel activity could thus account for its therapeutic action and/or physiological effects.
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Affiliation(s)
- M Chevalier
- Univ. Bordeaux, Centre de recherche Cardio-Thoracique de Bordeaux, Bordeaux, France
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45
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Tai CH, Yang YC, Pan MK, Huang CS, Kuo CC. Modulation of subthalamic T-type Ca(2+) channels remedies locomotor deficits in a rat model of Parkinson disease. J Clin Invest 2011; 121:3289-305. [PMID: 21737877 DOI: 10.1172/jci46482] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2011] [Accepted: 05/11/2011] [Indexed: 11/17/2022] Open
Abstract
An increase in neuronal burst activities in the subthalamic nucleus (STN) is a well-documented electrophysiological feature of Parkinson disease (PD). However, the causal relationship between subthalamic bursts and PD symptoms and the ionic mechanisms underlying the bursts remain to be established. Here, we have shown that T-type Ca(2+) channels are necessary for subthalamic burst firing and that pharmacological blockade of T-type Ca(2+) channels reduces motor deficits in a rat model of PD. Ni(2+), mibefradil, NNC 55-0396, and efonidipine, which inhibited T-type Ca(2+) currents in acutely dissociated STN neurons, but not Cd(2+) and nifedipine, which preferentially inhibited L-type or the other non–T-type Ca(2+) currents, effectively diminished burst activity in STN slices. Topical administration of inhibitors of T-type Ca(2+) channels decreased in vivo STN burst activity and dramatically reduced the locomotor deficits in a rat model of PD. Cd(2+) and nifedipine showed no such electrophysiological and behavioral effects. While low-frequency deep brain stimulation (DBS) has been considered ineffective in PD, we found that lengthening the duration of the low-frequency depolarizing pulse effectively improved behavioral measures of locomotion in the rat model of PD, presumably by decreasing the availability of T-type Ca(2+) channels. We therefore conclude that modulation of subthalamic T-type Ca(2+) currents and consequent burst discharges may provide new strategies for the treatment of PD.
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Affiliation(s)
- Chun-Hwei Tai
- Department of Physiology, National Taiwan University College of Medicine, Taipei, Taiwan
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46
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Masurkar AV, Chen WR. Calcium currents of olfactory bulb juxtaglomerular cells: profile and multiple conductance plateau potential simulation. Neuroscience 2011; 192:231-46. [PMID: 21704681 DOI: 10.1016/j.neuroscience.2011.06.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 05/06/2011] [Accepted: 06/03/2011] [Indexed: 11/25/2022]
Abstract
The olfactory glomerulus is the locus of information transfer between olfactory sensory neurons and output neurons of the olfactory bulb. Juxtaglomerular cells (JGCs) may influence intraglomerular processing by firing plateau potentials that support multiple spikes. It is unclear what inward currents mediate this firing pattern. In previous work, we characterized potassium currents of JGCs. We focus here on the inward currents using whole cell current clamp and voltage recording in a rat in vitro slice preparation, as well as computer simulation. We first showed that sodium current was not required to mediate plateau potentials. Voltage clamp characterization of calcium current (I(Ca)) determined that I(Ca) consisted of a slow activating, rapidly inactivating (τ(10%-90% rise) 6-8 ms, τ(inactivation) 38-77 ms) component I(cat1), similar to T-type currents, and a sustained (τ(inactivation)>>500 ms) component I(cat2), likely composed of L-type and P/Q-type currents. We used computer simulation to test their roles in plateau potential firing. We robustly modeled I(cat1) and I(cat2) to Hodgkin-Huxley schemes (m(3)h and m(2), respectively) and simulated a JGC plateau potential with six conductances: calcium currents as above, potassium currents from our prior study (A-type I(kt1), D-type I(kt2), delayed rectifier I(kt3)), and a fast sodium current (I(Na)). We demonstrated that I(cat1) was required for mediating the plateau potential, unlike I(Na) and I(cat2), and its τ(inactivation) determined plateau duration. We also found that I(kt1) dictated plateau potential shape more than I(kt2) and I(kt3). The influence of these two transient and opposing conductances suggests a unique mechanism of plateau potential physiology.
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Affiliation(s)
- A V Masurkar
- Department of Neurobiology, Yale University School of Medicine, New Haven, CT 06520, USA.
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Bidirectional plasticity in the primate inferior olive induced by chronic ethanol intoxication and sustained abstinence. Proc Natl Acad Sci U S A 2011; 108:10314-9. [PMID: 21642533 DOI: 10.1073/pnas.1017079108] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The brain adapts to chronic ethanol intoxication by altering synaptic and ion-channel function to increase excitability, a homeostatic counterbalance to inhibition by alcohol. Delirium tremens occurs when those adaptations are unmasked during withdrawal, but little is known about whether the primate brain returns to normal with repeated bouts of ethanol abuse and abstinence. Here, we show a form of bidirectional plasticity of pacemaking currents induced by chronic heavy drinking within the inferior olive of cynomolgus monkeys. Intracellular recordings of inferior olive neurons demonstrated that ethanol inhibited the tail current triggered by release from hyperpolarization (I(tail)). Both the slow deactivation of hyperpolarization-activated cyclic nucleotide-gated channels conducting the hyperpolarization-activated inward current and the activation of Ca(v)3.1 channels conducting the T-type calcium current (I(T)) contributed to I(tail), but ethanol inhibited only the I(T) component of I(tail). Recordings of inferior olive neurons obtained from chronically intoxicated monkeys revealed a significant up-regulation in I(tail) that was induced by 1 y of daily ethanol self-administration. The up-regulation was caused by a specific increase in I(T) which (i) greatly increased neurons' susceptibility for rebound excitation following hyperpolarization and (ii) may have accounted for intention tremors observed during ethanol withdrawal. In another set of monkeys, sustained abstinence produced the opposite effects: (i) a reduction in rebound excitability and (ii) a down-regulation of I(tail) caused by the down-regulation of both the hyperpolarization-activated inward current and I(T). Bidirectional plasticity of two hyperpolarization-sensitive currents following chronic ethanol abuse and abstinence may underlie persistent brain dysfunction in primates and be a target for therapy.
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48
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Ferron L, Ruchon Y, Renaud JF, Capuano V. T-type Ca²+ signalling regulates aldosterone-induced CREB activation and cell death through PP2A activation in neonatal cardiomyocytes. Cardiovasc Res 2011; 90:105-12. [PMID: 21123217 PMCID: PMC3058735 DOI: 10.1093/cvr/cvq379] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2010] [Revised: 11/08/2010] [Accepted: 11/25/2010] [Indexed: 01/10/2023] Open
Abstract
AIMS We have investigated Ca²(+) signalling generated by aldosterone-induced T-type current (I(CaT)), the effects of I(CaT) in neonatal cardiomyocytes, and a putative role for I(CaT) in cardiomyocytes during cardiac pathology induced by stenosis in an adult rat. METHODS AND RESULTS Neonatal rat cardiomyocytes treated with aldosterone showed an increase in I(CaT) density, principally due to the upregulation of the T-type channel Ca(v)3.1 (by 80%). Aldosterone activated cAMP-response element-binding protein (CREB), and this activation was enhanced by blocking I(CaT) or by inhibiting protein phosphatase 2A (PP2A) activity. Aldosterone induced PP2A activity, an induction that was prevented upon I(CaT) blockade. I(CaT) exerted a negative feedback regulation on the transcription of the Ca(v)3.1 gene, and the activation of PP2A by I(CaT) led to increased levels of the pro-apoptotic markers caspase 9 and Bcl-x(S) and decreased levels of the anti-apoptotic marker Bcl-2. These findings were corroborated by flow cytometry analysis for apoptosis and necrosis. Similarly, in a rat model of cardiac disease, I(CaT) re-emergence was associated with a decrease in CREB activation and was correlated with increases in caspase 9 and Bcl-x(S) and a decrease in Bcl-2 levels. CONCLUSION Our findings establish PP2A/CREB as targets of I(CaT)-generated Ca²(+) signalling and identify an important role for I(CaT) in cardiomyocyte cell death.
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MESH Headings
- Aldosterone/metabolism
- Animals
- Animals, Newborn
- Apoptosis
- Calcium Channels, T-Type/genetics
- Calcium Channels, T-Type/metabolism
- Calcium Signaling
- Cardiomegaly/enzymology
- Cardiomegaly/pathology
- Caspase 9/metabolism
- Cells, Cultured
- Cyclic AMP Response Element-Binding Protein/metabolism
- Disease Models, Animal
- Enzyme Activation
- Flow Cytometry
- Male
- Membrane Potentials
- Myocytes, Cardiac/enzymology
- Myocytes, Cardiac/pathology
- Necrosis
- Protein Phosphatase 2/metabolism
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/metabolism
- Rats
- Rats, Wistar
- Receptors, Glucocorticoid/metabolism
- Time Factors
- Transcription, Genetic
- bcl-X Protein/metabolism
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Affiliation(s)
- Laurent Ferron
- Département de Recherche Médicale, Remodelage tissulaire et fonctionnel: signalisation et physiopathologieCNRS-UMR8162, Le Plessis Robinson, France
| | - Yann Ruchon
- Département de Recherche Médicale, Remodelage tissulaire et fonctionnel: signalisation et physiopathologieCNRS-UMR8162, Le Plessis Robinson, France
- INSERM-U999, Université Paris-Sud XI, Hôpital Marie Lannelongue, 133 ave de la Résistance, 9230 Le Plessis Robinson, France
| | - Jean-François Renaud
- Département de Recherche Médicale, Remodelage tissulaire et fonctionnel: signalisation et physiopathologieCNRS-UMR8162, Le Plessis Robinson, France
- INSERM-U999, Université Paris-Sud XI, Hôpital Marie Lannelongue, 133 ave de la Résistance, 9230 Le Plessis Robinson, France
| | - Véronique Capuano
- Département de Recherche Médicale, Remodelage tissulaire et fonctionnel: signalisation et physiopathologieCNRS-UMR8162, Le Plessis Robinson, France
- INSERM-U999, Université Paris-Sud XI, Hôpital Marie Lannelongue, 133 ave de la Résistance, 9230 Le Plessis Robinson, France
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Li W, Zhang SL, Wang N, Zhang BB, Li M. Blockade of T-type Ca(2+) channels inhibits human ovarian cancer cell proliferation. Cancer Invest 2011; 29:339-46. [PMID: 21438841 DOI: 10.3109/07357907.2011.568565] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Regulation of Ca(2+) channels has been implicated in the progression of tumor cells. We report here that T-type Ca(2+) channel expression in human ovarian cancer tissues is greatly increased compared to normal ovarian tissues. Blockade of T-type Ca(2+) channel with NNC 55-0396, mibefradil, or by specifically knocking down the expression of these proteins with siRNA-Ca(v)3.1/3.2 suppressed the proliferation of two ovarian cancer cell lines and increased G0/G1 phase distribution in the cell cycle. Furthermore, NNC 55-0396 slowed ovarian cancer formation in nude mice. Therefore the function of T-type Ca(2+) channels is important for the proliferation of human ovarian cancer cells.
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Affiliation(s)
- Wei Li
- Department of Gynecology, Shengjing Hospital, China Medical University, Shenyang, China
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50
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Tscherter A, David F, Ivanova T, Deleuze C, Renger JJ, Uebele VN, Shin HS, Bal T, Leresche N, Lambert RC. Minimal alterations in T-type calcium channel gating markedly modify physiological firing dynamics. J Physiol 2011; 589:1707-24. [PMID: 21320888 DOI: 10.1113/jphysiol.2010.203836] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
T-type calcium channel isoforms expressed in heterologous systems demonstrate marked differences in the biophysical properties of the resulting calcium currents. Such heterogeneity in gating behaviour not only reflects structural differences but is also observed following the regulation of channel activity by a number of ligands. However, the physiological impact of these differences in gating parameters of the T channels has never been evaluated in situ where the unique interplay between T-type calcium and other intrinsic currents is conserved, and T channel activation can be triggered by synaptic stimulation. Here, using the dynamic clamp technique, artificial T conductances were re-incorporated in thalamic neurons devoid of endogenous T currents to dissect the physiological role of the T current gating diversity on neuronal excitability. We demonstrate that the specific kinetics of the T currents in thalamocortical and nucleus reticularis thalami neurons determine the characteristic firing patterns of these neurons. We show that subtle modifications in T channel gating that are at the limit of the resolution achieved in classical biophysical studies in heterologous expression systems have profound consequences for synaptically evoked firing dynamics in native neurons. Moreover, we demonstrate that the biophysical properties of the T current in the voltage region corresponding to the foot of the activation and inactivation curves drastically condition physiologically evoked burst firing with a high degree of synaptic input specificity.
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