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Sanchez-Sandoval AL, Hernández-Plata E, Gomora JC. Voltage-gated sodium channels: from roles and mechanisms in the metastatic cell behavior to clinical potential as therapeutic targets. Front Pharmacol 2023; 14:1206136. [PMID: 37456756 PMCID: PMC10348687 DOI: 10.3389/fphar.2023.1206136] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Accepted: 06/21/2023] [Indexed: 07/18/2023] Open
Abstract
During the second half of the last century, the prevalent knowledge recognized the voltage-gated sodium channels (VGSCs) as the proteins responsible for the generation and propagation of action potentials in excitable cells. However, over the last 25 years, new non-canonical roles of VGSCs in cancer hallmarks have been uncovered. Their dysregulated expression and activity have been associated with aggressive features and cancer progression towards metastatic stages, suggesting the potential use of VGSCs as cancer markers and prognostic factors. Recent work has elicited essential information about the signalling pathways modulated by these channels: coupling membrane activity to transcriptional regulation pathways, intracellular and extracellular pH regulation, invadopodia maturation, and proteolytic activity. In a promising scenario, the inhibition of VGSCs with FDA-approved drugs as well as with new synthetic compounds, reduces cancer cell invasion in vitro and cancer progression in vivo. The purpose of this review is to present an update regarding recent advances and ongoing efforts to have a better understanding of molecular and cellular mechanisms on the involvement of both pore-forming α and auxiliary β subunits of VGSCs in the metastatic processes, with the aim at proposing VGSCs as new oncological markers and targets for anticancer treatments.
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Affiliation(s)
- Ana Laura Sanchez-Sandoval
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
- Medicina Genómica, Hospital General de México “Dr Eduardo Liceaga”, Mexico City, Mexico
| | - Everardo Hernández-Plata
- Consejo Nacional de Humanidades, Ciencias y Tecnologías and Instituto Nacional de Medicina Genómica, Mexico City, Mexico
| | - Juan Carlos Gomora
- Departamento de Neuropatología Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
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2
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Bazzari AH, Bazzari FH. BDNF Therapeutic Mechanisms in Neuropsychiatric Disorders. Int J Mol Sci 2022; 23:ijms23158417. [PMID: 35955546 PMCID: PMC9368938 DOI: 10.3390/ijms23158417] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Revised: 07/26/2022] [Accepted: 07/28/2022] [Indexed: 11/16/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is the most abundant neurotrophin in the adult brain and functions as both a primary neurotrophic signal and a neuromodulator. It serves essential roles in neuronal development, maintenance, transmission, and plasticity, thereby influencing aging, cognition, and behavior. Accumulating evidence associates reduced central and peripheral BDNF levels with various neuropsychiatric disorders, supporting its potential utilization as a biomarker of central pathologies. Subsequently, extensive research has been conducted to evaluate restoring, or otherwise augmenting, BDNF transmission as a potential therapeutic approach. Promising results were indeed observed for genetic BDNF upregulation or exogenous administration using a multitude of murine models of neurological and psychiatric diseases. However, varying mechanisms have been proposed to underlie the observed therapeutic effects, and many findings indicate the engagement of disease-specific and other non-specific mechanisms. This is because BDNF essentially affects all aspects of neuronal cellular function through tropomyosin receptor kinase B (TrkB) receptor signaling, the disruptions of which vary between brain regions across different pathologies leading to diversified consequences on cognition and behavior. Herein, we review the neurophysiology of BDNF transmission and signaling and classify the converging and diverging molecular mechanisms underlying its therapeutic potentials in neuropsychiatric disorders. These include neuroprotection, synaptic maintenance, immunomodulation, plasticity facilitation, secondary neuromodulation, and preservation of neurovascular unit integrity and cellular viability. Lastly, we discuss several findings suggesting BDNF as a common mediator of the therapeutic actions of centrally acting pharmacological agents used in the treatment of neurological and psychiatric illness.
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Affiliation(s)
- Amjad H. Bazzari
- Faculty of Medicine, Arab American University, 13 Zababdeh, Jenin 240, Palestine
- Correspondence:
| | - Firas H. Bazzari
- Faculty of Pharmacy, Arab American University, 13 Zababdeh, Jenin 240, Palestine;
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3
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Abbaszadeh M, Sahin M, Ozgun A, Oncu G, Garipcan B, Saybasili H. A Transient Survival Model of Alteration of Electrophysiological Properties Due to Amyloid Beta Toxicity Based on SH-SY5Y Cell Line. Curr Alzheimer Res 2021; 17:1208-1213. [PMID: 33583383 DOI: 10.2174/1567205018666210212155750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 10/26/2020] [Accepted: 12/21/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Accumulation of toxic strands of amyloid beta (AB), which cause neurofibrillary tangles and, ultimately, cell death, is suspected to be the main culprit behind clinical symptoms of Alzheimer's disease. Although the mechanism of cell death due to AB accumulation is well known, the intermediate phase between the start of accumulation and cell death is less known and investigated, partially due to technical challenges in identifying partially affected cells. OBJECTIVE First, we aimed to establish an in vitro model that would show resilience against AB toxicity. Then we used morphological, molecular and electrophysiological assays to investigate how the characteristics of the surviving cells changed after AB toxicity. METHODS To investigate this phase, we used differentiation of SH-SY5Y neuroblastoma stem cells by Retinoic Acid (RA) and Brain Derived Neurotrophic Factor (BDNF) to establish an in vitro model which would be able to demonstrate various levels of resistance to AB toxicity. We utilized fluorescent microscopy and whole cell patch clamp recordings to investigate behavior of the model. RESULTS We observed significantly higher morphological resilience against AB toxicity in cells which were differentiated by both Retinoic Acid and Brain Derived Neurotrophic Factor compared to Retinoic Acid only. However, the electrophysiological properties of the Retinoic Acid + Brain-Derived Neurotrophic Factor differentiated cells were significantly altered after AB treatment. CONCLUSION We established a transient survival model for AB toxicity and observed the effects of AB on transmembrane currents of differentiated neurons.
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Affiliation(s)
- Morteza Abbaszadeh
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Meryem Sahin
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Alp Ozgun
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Gul Oncu
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Bora Garipcan
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
| | - Hale Saybasili
- Institute of Biomedical Engineering, Bogazici University, Istanbul, Turkey
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4
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Filipis L, Canepari M. Optical measurement of physiological sodium currents in the axon initial segment. J Physiol 2020; 599:49-66. [PMID: 33094478 DOI: 10.1113/jp280554] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 10/16/2020] [Indexed: 01/06/2023] Open
Abstract
KEY POINTS Τhe axonal Na+ fluorescence underlying an action potential in the axon initial segment was optically measured at unprecedented temporal resolution. The measurement allowed resolution of the kinetics of the Na+ current at different axonal locations. The distinct components of the Na+ current were correlated with the kinetics of the action potential. NEURON simulations from a modified published model qualitatively predicted the experimentally measured Na+ current. The present method permits the direct investigation of the kinetic behaviour of native Na+ channels under physiological and pathological conditions. ABSTRACT In most neurons of the mammalian central nervous system, the action potential (AP) is generated in the axon initial segment (AIS) by a fast Na+ current mediated by voltage-gated Na+ channels. While the axonal Na+ signal associated with the AP has been measured using fluorescent Na+ indicators, the insufficient resolution of these recordings has not allowed tracking the Na+ current kinetics underlying this fundamental event. In this article, we report the first optical measurement of Na+ currents in the AIS of pyramidal neurons of layer 5 of the somatosensory cortex from brain slices of the mouse. This measurement was obtained by achieving a temporal resolution of 100 μs in the Na+ imaging technique, with a pixel resolution of 0.5 μm, and by calculating the time-derivative of the Na+ change corrected for longitudinal diffusion. We identified a subthreshold current before the AP, a fast-inactivating current peaking during the rise of the AP and a non-inactivating current during the AP repolarization. We established a correlation between the kinetics of the non-inactivating current at different distances from the soma and the kinetics of the somatic AP. We quantitatively compared the experimentally measured Na+ current with the current obtained by computer simulation of published NEURON models, demonstrating how the present approach can lead to the correct estimate of the native behaviour of Na+ channels. Finally, we discuss how the present approach can be used to investigate the physiological or pathological function of different channel types during AP initiation and propagation.
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Affiliation(s)
- Luiza Filipis
- University of Grenoble Alpes, CNRS, LIPhy, Grenoble, F38000, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics, France
| | - Marco Canepari
- University of Grenoble Alpes, CNRS, LIPhy, Grenoble, F38000, France.,Laboratories of Excellence, Ion Channel Science and Therapeutics, France.,Institut National de la Santé et Recherche Médicale, France
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5
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Wadsworth PA, Singh AK, Nguyen N, Dvorak NM, Tapia CM, Russell WK, Stephan C, Laezza F. JAK2 regulates Nav1.6 channel function via FGF14 Y158 phosphorylation. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2020; 1867:118786. [PMID: 32599005 PMCID: PMC7984254 DOI: 10.1016/j.bbamcr.2020.118786] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/18/2020] [Accepted: 06/20/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Protein interactions between voltage-gated sodium (Nav) channels and accessory proteins play an essential role in neuronal firing and plasticity. However, a surprisingly limited number of kinases have been identified as regulators of these molecular complexes. We hypothesized that numerous as-of-yet unidentified kinases indirectly regulate the Nav channel via modulation of the intracellular fibroblast growth factor 14 (FGF14), an accessory protein with numerous unexplored phosphomotifs and required for channel function in neurons. METHODS Here we present results from an in-cell high-throughput screening (HTS) against the FGF14: Nav1.6 complex using >3000 diverse compounds targeting an extensive range of signaling pathways. Regulation by top kinase targets was then explored using in vitro phosphorylation, biophysics, mass-spectrometry and patch-clamp electrophysiology. RESULTS Compounds targeting Janus kinase 2 (JAK2) were over-represented among HTS hits. Phosphomotif scans supported by mass spectrometry revealed FGF14Y158, a site previously shown to mediate both FGF14 homodimerization and interactions with Nav1.6, as a JAK2 phosphorylation site. Following inhibition of JAK2, FGF14 homodimerization increased in a manner directly inverse to FGF14:Nav1.6 complex formation, but not in the presence of the FGF14Y158A mutant. Patch-clamp electrophysiology revealed that through Y158, JAK2 controls FGF14-dependent modulation of Nav1.6 channels. In hippocampal CA1 pyramidal neurons, the JAK2 inhibitor Fedratinib reduced firing by a mechanism that is dependent upon expression of FGF14. CONCLUSIONS These studies point toward a novel mechanism by which levels of JAK2 in neurons could directly influence firing and plasticity by controlling the FGF14 dimerization equilibrium, and thereby the availability of monomeric species for interaction with Nav1.6.
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Affiliation(s)
- Paul A Wadsworth
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA; Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Aditya K Singh
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Nghi Nguyen
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, USA
| | - Nolan M Dvorak
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Cynthia M Tapia
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA
| | - William K Russell
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX, USA
| | - Clifford Stephan
- HTS Screening Core, Center for Translational Cancer Research, Texas A&M Health Science Center: Institute of Biosciences and Technology, Houston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology & Toxicology, The University of Texas Medical Branch, Galveston, TX, USA; Center for Addiction Research, The University of Texas Medical Branch, Galveston, TX, USA.
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6
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Chiha W, Bartlett CA, Petratos S, Fitzgerald M, Harvey AR. Intravitreal application of AAV-BDNF or mutant AAV-CRMP2 protects retinal ganglion cells and stabilizes axons and myelin after partial optic nerve injury. Exp Neurol 2020; 326:113167. [PMID: 31904385 DOI: 10.1016/j.expneurol.2019.113167] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 12/20/2019] [Accepted: 12/31/2019] [Indexed: 12/29/2022]
Abstract
Secondary degeneration following an initial injury to the central nervous system (CNS) results in increased tissue loss and is associated with increasing functional impairment. Unilateral partial dorsal transection of the adult rat optic nerve (ON) has proved to be a useful experimental model in which to study factors that contribute to secondary degenerative events. Using this injury model, we here quantified the protective effects of intravitreally administered bi-cistronic adeno-associated viral (AAV2) vectors encoding either brain derived neurotrophic factor (BDNF) or a mutant, phospho-resistant, version of collapsin response mediator protein 2 (CRMP2T555A) on retinal ganglion cells (RGCs), their axons, and associated myelin. To test for potential synergistic interactions, some animals received combined injections of both vectors. Three months post-injury, all treatments maintained RGC numbers in central retina, but only AAV2-BDNF significantly protected ventrally located RGCs exclusively vulnerable to secondary degeneration. Behaviourally, treatments that involved AAV2-BDNF significantly restored the number of smooth-pursuit phases of optokinetic nystagmus. While all therapeutic regimens preserved axonal density and proportions of typical complexes, including heminodes and single nodes, BDNF treatments were generally more effective in maintaining the length of the node of Ranvier in myelin surrounding ventral ON axons after injury. Both AAV2-BDNF and AAV2-CRMP2T555A prevented injury-induced changes in G-ratio and overall myelin thickness, but only AAV2-BDNF administration protected against large-scale myelin decompaction in ventral ON. In summary, in a model of secondary CNS degeneration, both BDNF and CRMP2T555A vectors were neuroprotective, however different efficacies were observed for these overexpressed proteins in the retina and ON, suggesting disparate cellular and molecular targets driving responses for neural repair. The potential use of these vectors to treat other CNS injuries and pathologies is discussed.
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Affiliation(s)
- Wissam Chiha
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Carole A Bartlett
- School of Biological Sciences, The University of Western Australia, WA 6009, Australia
| | - Steven Petratos
- Department of Neuroscience, Monash University, VIC 3004, Australia
| | - Melinda Fitzgerald
- Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia; Curtin Health Innovation Research Institute, Curtin University, Belmont, WA 6102, Australia
| | - Alan R Harvey
- School of Human Sciences, The University of Western Australia, WA 6009, Australia; Perron Institute for Neurological and Translational Science, Nedlands, WA 6009, Australia.
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7
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Quantum transport and utilization of free energy in protein α-helices. ADVANCES IN QUANTUM CHEMISTRY 2020. [DOI: 10.1016/bs.aiq.2020.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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8
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Sun XD, Wang A, Ma P, Gong S, Tao J, Yu XM, Jiang X. Regulation of the firing activity by PKA-PKC-Src family kinases in cultured neurons of hypothalamic arcuate nucleus. J Neurosci Res 2019; 98:384-403. [PMID: 31407399 PMCID: PMC6916362 DOI: 10.1002/jnr.24516] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 07/18/2019] [Accepted: 07/30/2019] [Indexed: 12/19/2022]
Abstract
The cAMP‐dependent protein kinase A family (PKAs), protein kinase C family (PKCs), and Src family kinases (SFKs) are found to play important roles in pain hypersensitivity. However, more detailed investigations are still needed in order to understand the mechanisms underlying the actions of PKAs, PKCs, and SFKs. Neurons in the hypothalamic arcuate nucleus (ARC) are found to be involved in the regulation of pain hypersensitivity. Here we report that the action potential (AP) firing activity of ARC neurons in culture was up‐regulated by application of the adenylate cyclase activator forskolin or the PKC activator PMA, and that the forskolin or PMA application‐induced up‐regulation of AP firing activity could be blocked by pre‐application of the SFK inhibitor PP2. SFK activation also up‐regulated the AP firing activity and this effect could be prevented by pre‐application of the inhibitors of PKCs, but not of PKAs. Furthermore, we identified that forskolin or PMA application caused increases in the phosphorylation not only in PKAs at T197 or PKCs at S660 and PKCα/βII at T638/641, but also in SFKs at Y416. The forskolin or PMA application‐induced increase in the phosphorylation of PKAs or PKCs was not affected by pre‐treatment with PP2. The regulations of the SFK and AP firing activities by PKCs were independent upon the translocation of either PKCα or PKCβII. Thus, it is demonstrated that PKAs may act as an upstream factor(s) to enhance SFKs while PKCs and SFKs interact reciprocally, and thereby up‐regulate the AP firing activity in hypothalamic ARC neurons.
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Affiliation(s)
- Xiao-Dong Sun
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Anqi Wang
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Peng Ma
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Shan Gong
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Jin Tao
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Xian-Min Yu
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
| | - Xinghong Jiang
- Key Laboratory of Pain Basic Research and Clinical Therapy, Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, China
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9
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Bastos AEP, Costa PF, Varderidou-Minasian S, Altelaar M, Lima PA. Feeding cycle alters the biophysics and molecular expression of voltage-gated Na + currents in rat hippocampal CA1 neurones. Eur J Neurosci 2018; 49:1418-1435. [PMID: 30588669 DOI: 10.1111/ejn.14331] [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: 05/22/2018] [Revised: 12/04/2018] [Accepted: 12/14/2018] [Indexed: 11/28/2022]
Abstract
The function of hippocampus as a hub for energy balance is a subject of broad and current interest. This study aims at providing more evidence on this regard by addressing the effects of feeding cycle on the voltage-gated sodium (Na+ ) currents of acutely isolated Wistar rat hippocampal CA1 neurones. Specifically, by applying patch clamp techniques (whole cell voltage clamp and single channel in inside-out patches) we assessed the influence of feeding and fasting conditions on the intrinsic biophysical properties of Na+ currents. Additionally, mass spectrometry and western blotting experiments were used to address the effect of feeding cycle over the Na+ channel population of the rat hippocampus. Na+ currents were recorded in neurones obtained from fed and fasted animals (here termed "fed neurones" and "fasted neurones", respectively). Whole cell Na+ currents of fed neurones, as compared to fasted neurones, showed increased mean maximum current density and a higher "window current" amplitude. We demonstrate that these results are supported by an increased single channel Na+ conductance in fed neurones and, also, by a greater Nav1.2 channel density in plasma membrane-enriched fractions of fed samples (but not in whole hippocampus preparations). These results imply fast variations on the biophysics and molecular expression of Na+ currents of rat hippocampal CA1 neurones, throughout the feeding cycle. Thus, one may expect a differentiated regulation of the intrinsic neuronal excitability, which may account for the role of the hippocampus as a processor of satiety information.
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Affiliation(s)
- André E P Bastos
- Department of Chemistry and Biochemistry, Centre of Chemistry and Biochemistry, Faculty of Sciences University of Lisbon, Lisbon, Portugal.,Department of Physiology, Nova Medical School/Faculdade de Ciências Médicas, Lisbon, Portugal.,Sea4Us, Biotechnology and Marine Resources, Lda., Sagres, Portugal
| | - Pedro F Costa
- Department of Physiology, Nova Medical School/Faculdade de Ciências Médicas, Lisbon, Portugal
| | | | - Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Utrecht University, Utrecht, The Netherlands
| | - Pedro A Lima
- Department of Physiology, Nova Medical School/Faculdade de Ciências Médicas, Lisbon, Portugal.,Sea4Us, Biotechnology and Marine Resources, Lda., Sagres, Portugal
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10
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Iqbal SM, Aufy M, Shabbir W, Lemmens-Gruber R. Identification of phosphorylation sites and binding pockets for modulation of Na V 1.5 channel by Fyn tyrosine kinase. FEBS J 2018; 285:2520-2530. [PMID: 29734505 DOI: 10.1111/febs.14496] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Revised: 04/05/2018] [Accepted: 04/30/2018] [Indexed: 11/26/2022]
Abstract
Cardiac sodium channel NaV 1.5 is the predominant form of sodium channels in cardiomyocytes, which exists as a macromolecular complex and interacts with multiple protein partners. Fyn kinase is one of the interacting proteins which colocalize, phosphorylate and modulate the NaV 1.5 channel. To elaborate this interaction we created expression vectors for the N-terminal, intracellular loop, and C-terminal regions of the NaV 1.5 channel, to express in HEK-293 cells. By co-immunoprecipitation and anti-phosphotyrosine blotting, we identified proline-rich binding sites for Fyn kinase in the N-terminal, IC-loopi-ii and C-terminal. After binding, Fyn kinase phosphorylates tyrosine residues present in the N- and C-terminal, which produce a depolarizing shift of 7 mV in fast inactivation. The functional relevance of these binding and phosphorylation sites was further underpinned by creating full length mutants masking these sites sequentially. An activation and inactivation curves were recorded with or without co-expressed Fyn kinase which indicates that phosphorylation of tyrosine residues at positions 68, 87, 112 in the N-terminal and at positions 1811 and 1889 in the C-terminal creates a depolarizing shift in fast inactivation of NaV 1.5 channel.
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Affiliation(s)
- Shahid Muhammad Iqbal
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria.,Drugs Regulatory Authority of Pakistan, Islamabad, Pakistan
| | - Mohammed Aufy
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Waheed Shabbir
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
| | - Rosa Lemmens-Gruber
- Department of Pharmacology and Toxicology, University of Vienna, Vienna, Austria
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11
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Montersino A, Thomas GM. Slippery signaling: Palmitoylation-dependent control of neuronal kinase localization and activity. Mol Membr Biol 2016; 32:179-88. [PMID: 27241460 DOI: 10.1080/09687688.2016.1182652] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Modification of proteins with the lipid palmitate, a process called palmitoylation, is important for the normal function of neuronal cells. However, most attention has focused on how palmitoylation regulates the targeting and trafficking of neurotransmitter receptors and non-enzymatic scaffold proteins. In this review we discuss recent studies that suggest that palmitoylation also plays additional roles in neurons by controlling the localization, interactions and perhaps even the activity of protein kinases that play key roles in physiological neuronal regulation and in neuropathological processes.
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Affiliation(s)
- Audrey Montersino
- a Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair) and
| | - Gareth M Thomas
- a Shriners Hospitals Pediatric Research Center (Center for Neurorehabilitation and Neural Repair) and.,b Department of Anatomy and Cell Biology , Temple University School of Medicine , Philadelphia , PA , USA
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12
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Positive allosteric modulators of α7 nicotinic acetylcholine receptors affect neither the function of other ligand- and voltage-gated ion channels and acetylcholinesterase, nor β-amyloid content. Int J Biochem Cell Biol 2016; 76:19-30. [PMID: 27129924 DOI: 10.1016/j.biocel.2016.04.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 04/22/2016] [Accepted: 04/25/2016] [Indexed: 11/22/2022]
Abstract
The activity of positive allosteric modulators (PAMs) of α7 nicotinic acetylcholine receptors (AChRs), including 3-furan-2-yl-N-p-tolyl-acrylamide (PAM-2), 3-furan-2-yl-N-o-tolylacrylamide (PAM-3), and 3-furan-2-yl-N-phenylacrylamide (PAM-4), was tested on a variety of ligand- [i.e., human (h) α7, rat (r) α9α10, hα3-containing AChRs, mouse (m) 5-HT3AR, and several glutamate receptors (GluRs)] and voltage-gated (i.e., sodium and potassium) ion channels, as well as on acetylcholinesterase (AChE) and β-amyloid (Aβ) content. The functional results indicate that PAM-2 inhibits hα3-containing AChRs (IC50=26±6μM) with higher potency than that for NR1aNR2B and NR1aNR2A, two NMDA-sensitive GluRs. PAM-2 affects neither the activity of m5-HT3ARs, GluR5/KA2 (a kainate-sensitive GluR), nor AChE, and PAM-4 does not affect agonist-activated rα9α10 AChRs. Relevant clinical concentrations of PAM-2-4 do not inhibit Nav1.2 and Kv3.1 ion channels. These PAMs slightly enhance the activity of GluR1 and GluR2, two AMPA-sensitive GluRs. PAM-2 does not change the levels of Aβ42 in an Alzheimer's disease mouse model (i.e., 5XFAD). The molecular docking and dynamics results using the hα7 model suggest that the active sites for PAM-2 include the intrasubunit (i.e., PNU-120596 locus) and intersubunit sites. These results support our previous study showing that these PAMs are selective for the α7 AChR, and clarify that the procognitive/promnesic/antidepressant activity of PAM-2 is not mediated by other targets.
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13
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Scholz-Starke J, Cesca F. Stepping Out of the Shade: Control of Neuronal Activity by the Scaffold Protein Kidins220/ARMS. Front Cell Neurosci 2016; 10:68. [PMID: 27013979 PMCID: PMC4789535 DOI: 10.3389/fncel.2016.00068] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 03/01/2016] [Indexed: 12/31/2022] Open
Abstract
The correct functioning of the nervous system depends on the exquisitely fine control of neuronal excitability and synaptic plasticity, which relies on an intricate network of protein-protein interactions and signaling that shapes neuronal homeostasis during development and in adulthood. In this complex scenario, Kinase D interacting substrate of 220 kDa/ankyrin repeat-rich membrane spanning (Kidins220/ARMS) acts as a multi-functional scaffold protein with preferential expression in the nervous system. Engaged in a plethora of interactions with membrane receptors, cytosolic signaling components and cytoskeletal proteins, Kidins220/ARMS is implicated in numerous cellular functions including neuronal survival, neurite outgrowth and maturation and neuronal activity, often in the context of neurotrophin (NT) signaling pathways. Recent studies have highlighted a number of cell- and context-specific roles for this protein in the control of synaptic transmission and neuronal excitability, which are at present far from being completely understood. In addition, some evidence has began to emerge, linking alterations of Kidins220 expression to the onset of various neurodegenerative diseases and neuropsychiatric disorders. In this review, we present a concise summary of our fragmentary knowledge of Kidins220/ARMS biological functions, focusing on the mechanism(s) by which it controls various aspects of neuronal activity. We have tried, where possible, to discuss the available evidence in the wider context of NT-mediated regulation, and to outline emerging roles of Kidins220/ARMS in human pathologies.
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Affiliation(s)
| | - Fabrizia Cesca
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia Genova, Italy
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Chen H, Zeng Q, Yao C, Cai Z, Wei T, Huang Z, Su J. Src family tyrosine kinase inhibitors suppress Nav1.1 expression in cultured rat spiral ganglion neurons. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2016; 202:185-93. [PMID: 26790420 DOI: 10.1007/s00359-016-1066-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 12/22/2015] [Accepted: 01/01/2016] [Indexed: 11/25/2022]
Abstract
Src family kinases regulate neuronal voltage-gated Na(+) channels, which generate action potentials. The mechanisms of action, however, remain poorly understood. The aim of the present study was to further elucidate the effects of Src family kinases on Nav1.1 mRNA and protein expression in spiral ganglion neurons. Immunofluorescence staining techniques detected Nav1.1 expression in the spiral ganglion neurons. Additionally, quantitative PCR and western blot techniques were used to analyze Nav1.1 mRNA and protein expression, respectively, in spiral ganglion neurons following exposure to Src family kinase inhibitors PP2 (1 and 10 μM) and SU6656 (0.1 and 1 μM) for different lengths of time (6 and 24 h). In the spiral ganglion neurons, Nav1.1 protein expression was detected in the somas and axons. The Src family kinase inhibitors PP2 and SU6665 significantly decreased Nav1.1 mRNA and protein expression (p < 0.05), respectively, in the spiral ganglion neurons, and changes in expression were not dependent on time or dose (p > 0.05).
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Affiliation(s)
- Huiying Chen
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Qingjiao Zeng
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Chen Yao
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zheng Cai
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Tingjia Wei
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Zhihui Huang
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China
| | - Jiping Su
- Department of Otolaryngology-Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, 530021, Guangxi, China.
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Cesca F, Satapathy A, Ferrea E, Nieus T, Benfenati F, Scholz-Starke J. Functional Interaction between the Scaffold Protein Kidins220/ARMS and Neuronal Voltage-Gated Na+ Channels. J Biol Chem 2015; 290:18045-18055. [PMID: 26037926 DOI: 10.1074/jbc.m115.654699] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Indexed: 12/19/2022] Open
Abstract
Kidins220 (kinase D-interacting substrate of 220 kDa)/ankyrin repeat-rich membrane spanning (ARMS) acts as a signaling platform at the plasma membrane and is implicated in a multitude of neuronal functions, including the control of neuronal activity. Here, we used the Kidins220(-/-) mouse model to study the effects of Kidins220 ablation on neuronal excitability. Multielectrode array recordings showed reduced evoked spiking activity in Kidins220(-/-) hippocampal networks, which was compatible with the increased excitability of GABAergic neurons determined by current-clamp recordings. Spike waveform analysis further indicated an increased sodium conductance in this neuronal subpopulation. Kidins220 association with brain voltage-gated sodium channels was shown by co-immunoprecipitation experiments and Na(+) current recordings in transfected HEK293 cells, which revealed dramatic alterations of kinetics and voltage dependence. Finally, an in silico interneuronal model incorporating the Kidins220-induced Na(+) current alterations reproduced the firing phenotype observed in Kidins220(-/-) neurons. These results identify Kidins220 as a novel modulator of Nav channel activity, broadening our understanding of the molecular mechanisms regulating network excitability.
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Affiliation(s)
- Fabrizia Cesca
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, 16163 Genova, Italy.
| | - Annyesha Satapathy
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Enrico Ferrea
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Sensorimotor Group, German Primate Center, 37077 Göttingen, Germany
| | - Thierry Nieus
- Neuro Technology Department, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Department of Experimental Medicine, University of Genova, 16132 Genova, Italy
| | - Joachim Scholz-Starke
- Center for Synaptic Neuroscience, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Institute of Biophysics, Consiglio Nazionale delle Ricerche, 16149 Genova, Italy.
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Besson P, Driffort V, Bon É, Gradek F, Chevalier S, Roger S. How do voltage-gated sodium channels enhance migration and invasiveness in cancer cells? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2493-501. [PMID: 25922224 DOI: 10.1016/j.bbamem.2015.04.013] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Revised: 04/13/2015] [Accepted: 04/20/2015] [Indexed: 11/16/2022]
Abstract
Voltage-gated sodium channels are abnormally expressed in tumors, often as neonatal isoforms, while they are not expressed, or only at a low level, in the matching normal tissue. The level of their expression and their activity is related to the aggressiveness of the disease and to the formation of metastases. A vast knowledge on the regulation of their expression and functioning has been accumulated in normal excitable cells. This helped understand their regulation in cancer cells. However, how voltage-gated sodium channels impose a pro-metastatic behavior to cancer cells is much less documented. This aspect will be addressed in the review. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Pierre Besson
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France; Faculté de Sciences Pharmaceutiques, Université François Rabelais de Tours, France.
| | - Virginie Driffort
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France
| | - Émeline Bon
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France
| | - Frédéric Gradek
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France
| | - Stéphan Chevalier
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France; Faculté de Sciences Pharmaceutiques, Université François Rabelais de Tours, France
| | - Sébastien Roger
- Inserm UMR1069 "Nutrition, Croissance et Cancer", Faculté de Médecine, Université François Rabelais de Tours, France; Faculté des Sciences et Techniques, Université François Rabelais de Tours, France
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Carvacrol modulates voltage-gated sodium channels kinetics in dorsal root ganglia. Eur J Pharmacol 2015; 756:22-9. [PMID: 25794844 DOI: 10.1016/j.ejphar.2015.03.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2014] [Revised: 02/03/2015] [Accepted: 03/09/2015] [Indexed: 11/22/2022]
Abstract
Recent studies have shown that many of plant-derived compounds interact with specific ion channels and thereby modulate many sensing mechanisms, such as nociception. The monoterpenoid carvacrol (5-isopropyl-2-methylphenol) has an anti-nociceptive effect related to a reduction in neuronal excitability and voltage-gated Na(+) channels (NaV) inhibition in peripheral neurons. However, the detailed mechanisms of carvacrol-induced inhibition of neuronal NaV remain elusive. This study explores the interaction between carvacrol and NaV in isolated dorsal root ganglia neurons. Carvacrol reduced the total voltage-gated Na(+) current and tetrodotoxin-resistant (TTX-R) Na(+) current component in a concentration-dependent manner. Carvacrol accelerates current inactivation and induced a negative-shift in voltage-dependence of steady-state fast inactivation in total and TTX-R Na(+) current. Furthermore, carvacrol slowed the recovery from inactivation. Carvacrol provoked a leftward shift in both the voltage-dependence of steady-state inactivation and activation of the TTX-R Na(+) current component. In addition, carvacrol-induced inhibition of TTX-R Na(+) current was enhanced by an increase in stimulation frequency and when neurons were pre-conditioned with long depolarization pulse (5s at -50 mV). Taken all results together, we herein demonstrated that carvacrol affects NaV gating properties. The present findings would help to explain the mechanisms underlying the analgesic activity of carvacrol.
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Regulation of the cardiac Na+ channel NaV1.5 by post-translational modifications. J Mol Cell Cardiol 2015; 82:36-47. [PMID: 25748040 DOI: 10.1016/j.yjmcc.2015.02.013] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2014] [Revised: 01/28/2015] [Accepted: 02/17/2015] [Indexed: 02/07/2023]
Abstract
The cardiac voltage-gated Na(+) channel, Na(V)1.5, is responsible for the upstroke of the action potential in cardiomyocytes and for efficient propagation of the electrical impulse in the myocardium. Even subtle alterations of Na(V)1.5 function, as caused by mutations in its gene SCN5A, may lead to many different arrhythmic phenotypes in carrier patients. In addition, acquired malfunctions of Na(V)1.5 that are secondary to cardiac disorders such as heart failure and cardiomyopathies, may also play significant roles in arrhythmogenesis. While it is clear that the regulation of Na(V)1.5 protein expression and function tightly depends on genetic mechanisms, recent studies have demonstrated that Na(V)1.5 is the target of various post-translational modifications that are pivotal not only in physiological conditions, but also in disease. In this review, we examine the recent literature demonstrating glycosylation, phosphorylation by Protein Kinases A and C, Ca(2+)/Calmodulin-dependent protein Kinase II, Phosphatidylinositol 3-Kinase, Serum- and Glucocorticoid-inducible Kinases, Fyn and Adenosine Monophosphate-activated Protein Kinase, methylation, acetylation, redox modifications, and ubiquitylation of Na(V)1.5. Modern and sensitive mass spectrometry approaches, applied directly to channel proteins that were purified from native cardiac tissues, have enabled the determination of the precise location of post-translational modification sites, thus providing essential information for understanding the mechanistic details of these regulations. The current challenge is first, to understand the roles of these modifications on the expression and the function of Na(V)1.5, and second, to further identify other chemical modifications. It is postulated that the diversity of phenotypes observed with Na(V)1.5-dependent disorders may partially arise from the complex post-translational modifications of channel protein components.
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19
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Knox R, Jiang X. Fyn in Neurodevelopment and Ischemic Brain Injury. Dev Neurosci 2015; 37:311-20. [PMID: 25720756 DOI: 10.1159/000369995] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Accepted: 11/18/2014] [Indexed: 12/11/2022] Open
Abstract
The Src family kinases (SFKs) are nonreceptor protein tyrosine kinases that are implicated in many normal and pathological processes in the nervous system. The SFKs Fyn, Src, Yes, Lyn, and Lck are expressed in the brain. This review will focus on Fyn, as Fyn mutant mice have striking phenotypes in the brain and Fyn has been shown to be involved in ischemic brain injury in adult rodents and, with our work, in neonatal animals. An understanding of Fyn's role in neurodevelopment and disease will allow researchers to target pathological pathways while preserving protective ones.
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Affiliation(s)
- Renatta Knox
- Department of Pediatrics, Weill Cornell Medical College, New York, N.Y., USA
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20
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SRC tyrosine kinases regulate neuronal differentiation of mouse embryonic stem cells via modulation of voltage-gated sodium channel activity. Neurochem Res 2015; 40:674-87. [PMID: 25577147 DOI: 10.1007/s11064-015-1514-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Revised: 12/10/2014] [Accepted: 01/07/2015] [Indexed: 12/19/2022]
Abstract
Voltage-gated Na(+) channel activity is vital for the proper function of excitable cells and has been indicated in nervous system development. Meanwhile, the Src family of non-receptor tyrosine kinases (SFKs) has been implicated in the regulation of Na(+) channel activity. The present investigation tests the hypothesis that Src family kinases influence neuronal differentiation via a chronic regulation of Na(+) channel functionality. In cultured mouse embryonic stem (ES) cells undergoing neural induction and terminal neuronal differentiation, SFKs showed distinct stage-specific expression patterns during the differentiation process. ES cell-derived neuronal cells expressed multiple voltage-gated Na(+) channel proteins (Nav) and underwent a gradual increase in Na(+) channel activity. While acute inhibition of SFKs using the Src family inhibitor PP2 suppressed the Na(+) current, chronic inhibition of SFKs during early neuronal differentiation of ES cells did not change Nav expression. However, a long-lasting block of SFK significantly altered electrophysiological properties of the Na(+) channels, shown as a right shift of the current-voltage relationship of the Na(+) channels, and reduced the amplitude of Na(+) currents recorded in drug-free solutions. Immunocytochemical staining of differentiated cells subjected to the chronic exposure of a SFK inhibitor, or the Na(+) channel blocker tetrodotoxin, showed no changes in the number of NeuN-positive cells; however, both treatments significantly hindered neurite outgrowth. These findings suggest that SFKs not only modulate the Na(+) channel activation acutely, but the tonic activity of SFKs is also critical for normal development of functional Na(+) channels and neuronal differentiation or maturation of ES cells.
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21
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Neumann JT, Thompson JW, Raval AP, Cohan CH, Koronowski KB, Perez-Pinzon MA. Increased BDNF protein expression after ischemic or PKC epsilon preconditioning promotes electrophysiologic changes that lead to neuroprotection. J Cereb Blood Flow Metab 2015; 35:121-30. [PMID: 25370861 PMCID: PMC4294405 DOI: 10.1038/jcbfm.2014.185] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Revised: 10/02/2014] [Accepted: 10/03/2014] [Indexed: 01/06/2023]
Abstract
Ischemic preconditioning (IPC) via protein kinase C epsilon (PKCɛ) activation induces neuroprotection against lethal ischemia. Brain-derived neurotrophic factor (BDNF) is a pro-survival signaling molecule that modulates synaptic plasticity and neurogenesis. Interestingly, BDNF mRNA expression increases after IPC. In this study, we investigated whether IPC or pharmacological preconditioning (PKCɛ activation) promoted BDNF-induced neuroprotection, if neuroprotection by IPC or PKCɛ activation altered neuronal excitability, and whether these changes were BDNF-mediated. We used both in vitro (hippocampal organotypic cultures and cortical neuronal-glial cocultures) and in vivo (acute hippocampal slices 48 hours after preconditioning) models of IPC or PKCɛ activation. BDNF protein expression increased 24 to 48 hours after preconditioning, where inhibition of the BDNF Trk receptors abolished neuroprotection against oxygen and glucose deprivation (OGD) in vitro. In addition, there was a significant decrease in neuronal firing frequency and increase in threshold potential 48 hours after preconditioning in vivo, where this threshold modulation was dependent on BDNF activation of Trk receptors in excitatory cortical neurons. In addition, 48 hours after PKCɛ activation in vivo, the onset of anoxic depolarization during OGD was significantly delayed in hippocampal slices. Overall, these results suggest that after IPC or PKCɛ activation, there are BDNF-dependent electrophysiologic modifications that lead to neuroprotection.
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Affiliation(s)
- Jake T Neumann
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - John W Thompson
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Ami P Raval
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Charles H Cohan
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [4] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Kevin B Koronowski
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
| | - Miguel A Perez-Pinzon
- 1] Cerebral Vascular Disease Research Laboratories, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [2] Evelyn F. McKnight Brain Institute, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [3] Department of Neurology, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA [4] Neuroscience Program, University of Miami Leonard M. Miller School of Medicine, Miami, Florida, USA
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Smith PA. BDNF: No gain without pain? Neuroscience 2014; 283:107-23. [DOI: 10.1016/j.neuroscience.2014.05.044] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/16/2014] [Accepted: 05/21/2014] [Indexed: 12/22/2022]
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23
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Nadim F, Bucher D. Neuromodulation of neurons and synapses. Curr Opin Neurobiol 2014; 29:48-56. [PMID: 24907657 DOI: 10.1016/j.conb.2014.05.003] [Citation(s) in RCA: 194] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 05/09/2014] [Accepted: 05/09/2014] [Indexed: 12/15/2022]
Abstract
Neuromodulation underlies the flexibility of neural circuit operation and behavior. Individual neuromodulators can have divergent actions in a neuron by targeting multiple physiological mechanisms. Conversely, multiple neuromodulators may have convergent actions through overlapping targets. The divergent and convergent neuromodulator actions can be unambiguously synergistic or antagonistic, but neuromodulation often entails balanced adjustment of nonlinear membrane and synaptic properties by targeting ion channel and synaptic dynamics rather than just excitability or synaptic strength. In addition, neuromodulators can exert effects at multiple timescales, from short-term adjustments of neuron and synapse function to persistent long-term regulation. This short review summarizes some highlights of the diverse actions of neuromodulators on ion channel and synaptic properties.
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Affiliation(s)
- Farzan Nadim
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States.
| | - Dirk Bucher
- Federated Department of Biological Sciences, New Jersey Institute of Technology and Rutgers University, 323 Martin Luther King Blvd, Newark, NJ 07102, United States
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Abstract
Brain-derived neurotrophic factor (BDNF)--a member of a small family of secreted proteins that includes nerve growth factor, neurotrophin 3 and neurotrophin 4--has emerged as a key regulator of neural circuit development and function. The expression, secretion and actions of BDNF are directly controlled by neural activity, and secreted BDNF is capable of mediating many activity-dependent processes in the mammalian brain, including neuronal differentiation and growth, synapse formation and plasticity, and higher cognitive functions. This Review summarizes some of the recent progress in understanding the cellular and molecular mechanisms underlying neurotrophin regulation of neural circuits. The focus of the article is on BDNF, as this is the most widely expressed and studied neurotrophin in the mammalian brain.
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Neuregulin directly decreases voltage-gated sodium current in hippocampal ErbB4-expressing interneurons. J Neurosci 2013; 32:13889-95. [PMID: 23035098 DOI: 10.1523/jneurosci.1420-12.2012] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Neuregulin 1 (NRG1)/ErbB4 signaling pathway has been genetically and functionally implicated in the etiology underlying schizophrenia, and in the regulation of glutamatergic pyramidal neuron function and plasticity. However, ErbB4 receptors are expressed in subpopulations of GABAergic interneurons, but not in hippocampal or cortical pyramidal neurons, indicating that NRG1 effects on principal neurons are indirect. Consistent with these findings, NRG1 effects on hippocampal long-term potentiation at CA1 pyramidal neuron synapses in slices are mediated indirectly by dopamine. Here we studied whether NRG/ErbB signaling directly regulates interneuron intrinsic excitability by pharmacologically isolating ErbB4-expressing neurons in rat dissociated hippocampal cultures, which lack dopaminergic innervation. We found that NRG1 acutely attenuates ErbB4-expressing interneuron excitability by depolarizing the firing threshold; neurons treated with the pan-ErbB inhibitor PD158780 or negative for ErbB4 were unaffected. These effects of NRG1 are primarily attributable to decreased voltage-gated sodium channel activity, as current density was attenuated by ∼60%. In stark contrast, NRG1 had minor effects on whole-cell potassium currents. Our data reveal the direct actions of NRG1 signaling in ErbB4-expressing interneurons, and offer novel insight into how NRG1/ErbB4 signaling can impact hippocampal activity.
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Ebner-Bennatan S, Patrich E, Peretz A, Kornilov P, Tiran Z, Elson A, Attali B. Multifaceted modulation of K+ channels by protein-tyrosine phosphatase ε tunes neuronal excitability. J Biol Chem 2012; 287:27614-28. [PMID: 22722941 PMCID: PMC3431696 DOI: 10.1074/jbc.m112.342519] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 06/19/2012] [Indexed: 11/06/2022] Open
Abstract
Non-receptor-tyrosine kinases (protein-tyrosine kinases) and non-receptor tyrosine phosphatases (PTPs) have been implicated in the regulation of ion channels, neuronal excitability, and synaptic plasticity. We previously showed that protein-tyrosine kinases such as Src kinase and PTPs such as PTPα and PTPε modulate the activity of delayed-rectifier K(+) channels (I(K)). Here we show cultured cortical neurons from PTPε knock-out (EKO) mice to exhibit increased excitability when compared with wild type (WT) mice, with larger spike discharge frequency, enhanced fast after-hyperpolarization, increased after-depolarization, and reduced spike width. A decrease in I(K) and a rise in large-conductance Ca(2+)-activated K(+) currents (mBK) were observed in EKO cortical neurons compared with WT. Parallel studies in transfected CHO cells indicate that Kv1.1, Kv1.2, Kv7.2/7.3, and mBK are plausible molecular correlates of this multifaceted modulation of K(+) channels by PTPε. In CHO cells, Kv1.1, Kv1.2, and Kv7.2/7.3 K(+) currents were up-regulated by PTPε, whereas mBK channel activity was reduced. The levels of tyrosine phosphorylation of Kv1.1, Kv1.2, Kv7.3, and mBK potassium channels were increased in the brain cortices of neonatal and adult EKO mice compared with WT, suggesting that PTPε in the brain modulates these channel proteins. Our data indicate that in EKO mice, the lack of PTPε-mediated dephosphorylation of Kv1.1, Kv1.2, and Kv7.3 leads to decreased I(K) density and enhanced after-depolarization. In addition, the deficient PTPε-mediated dephosphorylation of mBK channels likely contributes to enhanced mBK and fast after-hyperpolarization, spike shortening, and consequent increase in neuronal excitability observed in cortical neurons from EKO mice.
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Affiliation(s)
- Sharon Ebner-Bennatan
- From the Department of Physiology and Pharmacology of the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 69978 and
| | - Eti Patrich
- From the Department of Physiology and Pharmacology of the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 69978 and
| | - Asher Peretz
- From the Department of Physiology and Pharmacology of the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 69978 and
| | - Polina Kornilov
- From the Department of Physiology and Pharmacology of the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 69978 and
| | - Zohar Tiran
- the Department of Molecular Genetics, the Weizmann Institute of Science, Rehovot 76100, Israel
| | - Ari Elson
- the Department of Molecular Genetics, the Weizmann Institute of Science, Rehovot 76100, Israel
| | - Bernard Attali
- From the Department of Physiology and Pharmacology of the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel 69978 and
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Feng S, Pflueger M, Lin SX, Groveman BR, Su J, Yu XM. Regulation of voltage-gated sodium current by endogenous Src family kinases in cochlear spiral ganglion neurons in culture. Pflugers Arch 2012; 463:571-84. [PMID: 22297656 DOI: 10.1007/s00424-012-1072-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2011] [Revised: 12/09/2011] [Accepted: 01/02/2012] [Indexed: 01/28/2023]
Abstract
Voltage-gated sodium (Na+) and potassium (K+)channels have been found to be regulated by Src family kinases(SFKs).However, how these channels are regulated by SFKs in cochlear spiral ganglion neurons (SGNs) remains unknown.Here, we report that altering the activity of endogenous SFKs modulated voltage-gated Na+, but not K+, currents recorded in embryonic SGNs in culture. Voltage-gated Na+ current was suppressed by inhibition of endogenous SFKs or just Src and potentiated by the activation of these enzymes. Detailed investigations showed that under basal conditions, SFK inhibitor application did not significantly affect the voltage-dependent activation, but shifted the steady-state inactivation curves of Na+ currents and delayed the recovery of Na+ currents from inactivation. Application of Src specific inhibitor, Src40–58,not only shifted the inactivation curve but also delayed the recovery of Na+ currents and moved the voltage-dependent activation curve towards the left. The pre-inhibition of SFKs occluded all the effects induced by Src40–58 application, except the left shift of the activation curve. The activation of SFKs did not change either steady-state inactivation or recovery of Na+ currents, but caused the left shift of the activation curve.SFK inhibitor application effectively prevented all the effects induced by SFK activation, suggesting that both the voltage-dependent activation and steady-state inactivation of Na+ current are subjects of SFK regulation. The different effects induced by activation versus inhibition of SFKs implied that under basal conditions, endogenously active and inactive SFKs might be differentially involved in the regulation of voltage-gated Na+ channels in SGNs.
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Affiliation(s)
- Shuang Feng
- Department of Otolaryngology—Head and Neck Surgery, First Affiliated Hospital, Guangxi Medical University, Nanning, Guangxi, People’s Republic of China
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Abstract
The action potential generally begins in the axon initial segment (AIS), a principle confirmed by 60 years of research; however, the most recent advances have shown that a very rich biology underlies this simple observation. The AIS has a remarkably complex molecular composition, with a wide variety of ion channels and attendant mechanisms for channel localization, and may feature membrane domains each with distinct roles in excitation. Its function may be regulated in the short term through the action of neurotransmitters, in the long term through activity- and Ca(2+)-dependent processes. Thus, the AIS is not merely the beginning of the axon, but rather a key site in the control of neuronal excitability.
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Affiliation(s)
- Kevin J Bender
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, Oregon 97239, USA.
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Groveman BR, Feng S, Fang XQ, Pflueger M, Lin SX, Bienkiewicz EA, Yu X. The regulation of N-methyl-D-aspartate receptors by Src kinase. FEBS J 2011; 279:20-8. [PMID: 22060915 DOI: 10.1111/j.1742-4658.2011.08413.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Src family kinases (SFKs) play critical roles in the regulation of many cellular functions by growth factors, G-protein-coupled receptors and ligand-gated ion channels. Recent data have shown that SFKs serve as a convergent point of multiple signaling pathways regulating N-methyl-d-aspartate (NMDA) receptors in the central nervous system. Multiple SFK molecules, such as Src and Fyn, closely associate with their substrate, NMDA receptors, via indirect and direct binding mechanisms. The NMDA receptor is associated with an SFK signaling complex consisting of SFKs; the SFK-activating phosphatase, protein tyrosine phosphatase α; and the SFK-inactivating kinase, C-terminal Src kinase. Early studies have demonstrated that intramolecular interactions with the SH2 or SH3 domain lock SFKs in a closed conformation. Disruption of the interdomain interactions can induce the activation of SFKs with multiple signaling pathways involved in regulation of this process. The enzyme activity of SFKs appears 'graded', exhibiting different levels coinciding with activation states. It has also been proposed that the SH2 and SH3 domains may stimulate catalytic activity of protein tyrosine kinases, such as Abl. Recently, it has been found that the enzyme activity of neuronal Src protein is associated with its stability, and that the SH2 and SH3 domain interactions may act not only to constrain the activation of neuronal Src, but also to regulate the enzyme activity of active neuronal Src. Collectively, these findings demonstrate novel mechanisms underlying the regulation of SFKs.
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Affiliation(s)
- Bradley R Groveman
- Department of Biomedical Sciences, Florida State University, Tallahassee, FL 32306, USA.
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30
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An antinociceptive role for substance P in acid-induced chronic muscle pain. Proc Natl Acad Sci U S A 2011; 109:E76-83. [PMID: 22084095 DOI: 10.1073/pnas.1108903108] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Release of substance P (SP) from nociceptive nerve fibers and activation of its receptor neurokinin 1 (NK1) are important effectors in the transmission of pain signals. Nonetheless, the role of SP in muscle pain remains unknown. Here we show that a single i.m. acid injection in mice lacking SP signaling by deletion of the tachykinin precursor 1 (Tac1) gene or coadministration of NK1 receptor antagonists produces long-lasting hyperalgesia rather than the transient hyperalgesia seen in control animals. The inhibitory effect of SP was found exclusively in neurons expressing acid-sensing ion channel 3, where SP enhances M-channel-like potassium currents through the NK1 receptor in a G protein-independent but tyrosine kinase-dependent manner. Furthermore, the SP signaling could alter action potential thresholds and modulate the expression of TTX-resistant sodium currents in medium-sized muscle nociceptors. Thus, i.m. SP mediates an unconventional NK1 receptor signal pathway to inhibit acid activation in muscle nociceptors, resulting in an unexpected antinociceptive effect against chronic mechanical hyperalgesia, here induced by repeated i.m. acid injection.
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31
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Beltran-Alvarez P, Pagans S, Brugada R. The cardiac sodium channel is post-translationally modified by arginine methylation. J Proteome Res 2011; 10:3712-9. [PMID: 21726068 DOI: 10.1021/pr200339n] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The α subunit of the cardiac sodium channel (Na(v)1.5) is an essential protein in the initial depolarization phase of the cardiomyocyte action potential. Post-translational modifications such as phosphorylation are known to regulate Na(v)1.5 function. Here, we used a proteomic approach for the study of the post-translational modifications of Na(v)1.5 using tsA201 cells as a model system. We generated a stable cell line expressing Na(v)1.5, purified the sodium channel, and analyzed Na(v)1.5 by MALDI-TOF and LC-MS/MS. We report the identification of arginine methylation as a novel post-translational modification of Na(v)1.5. R513, R526, and R680, located in the linker between domains I and II in Na(v)1.5, were found in mono- or dimethylated states. The functional relevance of arginine methylation in Na(v)1.5 is underscored by the fact that R526H and R680H are known Na(v)1.5 mutations causing Brugada and long QT type 3 syndromes, respectively. Our work describes for the first time arginine methylation in the voltage-gated ion channel superfamily.
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Affiliation(s)
- Pedro Beltran-Alvarez
- Cardiovascular Genetics Center, Institut d'Investigació Biomèdica de Girona, Hospital Dr. Josep Trueta, Girona, Spain
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32
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Brain-derived neurotrophic factor mediates non-cell-autonomous regulation of sensory neuron position and identity. J Neurosci 2010; 30:14513-21. [PMID: 20980609 DOI: 10.1523/jneurosci.4025-10.2010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
During development, neurons migrate considerable distances to reside in locations that enable their individual functional roles. Whereas migration mechanisms have been extensively studied, much less is known about how neurons remain in their ideal locations. We sought to identify factors that maintain the position of postmigratory dorsal root ganglion neurons, neural crest derivatives for which migration and final position play an important developmental role. We found that an early developing population of sensory neurons maintains the position of later born dorsal root ganglia neurons in an activity-dependent manner. Further, inhibiting or increasing the function of brain-derived neurotrophic factor induces or prevents, respectively, migration of dorsal root ganglia neurons out of the ganglion to locations where they acquire a new identity. Overall, the results demonstrate that neurotrophins mediate non-cell-autonomous maintenance of position and thereby the identity of differentiated neurons.
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33
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Scheuer T. Regulation of sodium channel activity by phosphorylation. Semin Cell Dev Biol 2010; 22:160-5. [PMID: 20950703 DOI: 10.1016/j.semcdb.2010.10.002] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Revised: 10/04/2010] [Accepted: 10/05/2010] [Indexed: 12/24/2022]
Abstract
Voltage-gated sodium channels carry the major inward current responsible for action potential depolarization in excitable cells as well as providing additional inward current that modulates overall excitability. Both their expression and function is under tight control of protein phosphorylation by specific kinases and phosphatases and this control is particular to each type of sodium channel. This article examines the impact and mechanism of phosphorylation for isoforms where it has been studied in detail in an attempt to delineate common features as well as differences.
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Affiliation(s)
- Todd Scheuer
- Department of Pharmacology, University of Washington School of Medicine, Seattle, WA 98195-7280, United States.
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Catterall WA. Signaling complexes of voltage-gated sodium and calcium channels. Neurosci Lett 2010; 486:107-16. [PMID: 20816922 DOI: 10.1016/j.neulet.2010.08.085] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2010] [Revised: 08/27/2010] [Accepted: 08/29/2010] [Indexed: 01/09/2023]
Abstract
Membrane depolarization and intracellular Ca(2+) transients generated by activation of voltage-gated Na+ and Ca(2+) channels are local signals, which initiate physiological processes such as action potential conduction, synaptic transmission, and excitation-contraction coupling. Targeting of effector proteins and regulatory proteins to ion channels is an important mechanism to ensure speed, specificity, and precise regulation of signaling events in response to local stimuli. This article reviews experimental results showing that Na+ and Ca(2+) channels form local signaling complexes, in which effector proteins, anchoring proteins, and regulatory proteins interact directly with ion channels. The intracellular domains of these channels serve as signaling platforms, mediating their participation in intracellular signaling processes. These protein-protein interactions are important for regulation of cellular plasticity through modulation of Na+ channel function in brain neurons, for short-term synaptic plasticity through modulation of presynaptic Ca(V)2 channels, and for the fight-or-flight response through regulation of postsynaptic Ca(V)1 channels in skeletal and cardiac muscle. These localized signaling complexes are essential for normal function and regulation of electrical excitability, synaptic transmission, and excitation-contraction coupling.
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Affiliation(s)
- William A Catterall
- Department of Pharmacology, Box 357280, University of Washington, Seattle, WA 98195-7280, United States.
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Chen Y, Balasubramanyan S, Lai AY, Todd KG, Smith PA. Effects of sciatic nerve axotomy on excitatory synaptic transmission in rat substantia gelatinosa. J Neurophysiol 2009; 102:3203-15. [PMID: 19793881 DOI: 10.1152/jn.00296.2009] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Injury or section of a peripheral nerve can promote chronic neuropathic pain. This is initiated by the appearance and persistence of ectopic spontaneous activity in primary afferent neurons that promotes a secondary, enduring increase in excitability of sensory circuits in the spinal dorsal horn ("central sensitization"). We have previously shown that 10-20 days of chronic constriction injury (CCI) of rat sciatic nerve produce a characteristic "electrophysiological signature" or pattern of changes in synaptic excitation of five different electrophysiologically defined neuronal phenotypes in the substantia gelatinosa of the dorsal horn. Although axotomy and CCI send different signals to the dorsal horn, we now find, using whole cell recording, that the "electrophysiological signature" produced 12-22 days after sciatic axotomy is quite similar to that seen with CCI. Axotomy thus has little effect on resting membrane potential, rheobase, current-voltage characteristics, or excitability of most neuron types; however, it does decrease excitatory synaptic drive to tonic firing neurons, while increasing that to delay firing neurons. Since many tonic neurons are GABAergic, whereas delay neurons do not contain gamma-aminobutyric acid, axotomy may reduce synaptic excitation of inhibitory neurons while increasing that of excitatory neurons. Further analysis of spontaneous and miniature (tetrodotoxin-resistant) excitatory postsynaptic currents is consistent with the possibility that decreased excitation of tonic neurons reflects loss of presynaptic contacts. By contrast, increased excitation of "delay" neurons may reflect increased frequency of discharge of presynaptic action potentials. This would explain how synaptic excitation of tonic cells decreases despite the fact that axotomy increases spontaneous activity in primary afferent neurons.
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Affiliation(s)
- Yishen Chen
- Department of Pharmacology, University of Alberta, Edmonton, Alberta, Canada
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36
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Protein–protein interactions involving voltage-gated sodium channels: Post-translational regulation, intracellular trafficking and functional expression. Int J Biochem Cell Biol 2009; 41:1471-81. [DOI: 10.1016/j.biocel.2009.01.016] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2008] [Revised: 01/23/2009] [Accepted: 01/26/2009] [Indexed: 01/06/2023]
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Leng J, Jiang L, Chen H, Zhang X. Brain-derived neurotrophic factor and electrophysiological properties of voltage-gated ion channels during neuronal stem cell development. Brain Res 2009; 1272:14-24. [DOI: 10.1016/j.brainres.2009.03.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/14/2009] [Accepted: 03/17/2009] [Indexed: 01/19/2023]
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38
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Aman TK, Grieco-Calub TM, Chen C, Rusconi R, Slat EA, Isom LL, Raman IM. Regulation of persistent Na current by interactions between beta subunits of voltage-gated Na channels. J Neurosci 2009; 29:2027-42. [PMID: 19228957 PMCID: PMC2667244 DOI: 10.1523/jneurosci.4531-08.2009] [Citation(s) in RCA: 137] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2008] [Revised: 12/30/2008] [Accepted: 01/06/2009] [Indexed: 11/21/2022] Open
Abstract
The beta subunits of voltage-gated Na channels (Scnxb) regulate the gating of pore-forming alpha subunits, as well as their trafficking and localization. In heterologous expression systems, beta1, beta2, and beta3 subunits influence inactivation and persistent current in different ways. To test how the beta4 protein regulates Na channel gating, we transfected beta4 into HEK (human embryonic kidney) cells stably expressing Na(V)1.1. Unlike a free peptide with a sequence from the beta4 cytoplasmic domain, the full-length beta4 protein did not block open channels. Instead, beta4 expression favored open states by shifting activation curves negative, decreasing the slope of the inactivation curve, and increasing the percentage of noninactivating current. Consequently, persistent current tripled in amplitude. Expression of beta1 or chimeric subunits including the beta1 extracellular domain, however, favored inactivation. Coexpressing Na(V)1.1 and beta4 with beta1 produced tiny persistent currents, indicating that beta1 overcomes the effects of beta4 in heterotrimeric channels. In contrast, beta1(C121W), which contains an extracellular epilepsy-associated mutation, did not counteract the destabilization of inactivation by beta4 and also required unusually large depolarizations for channel opening. In cultured hippocampal neurons transfected with beta4, persistent current was slightly but significantly increased. Moreover, in beta4-expressing neurons from Scn1b and Scn1b/Scn2b null mice, entry into inactivated states was slowed. These data suggest that beta1 and beta4 have antagonistic roles, the former favoring inactivation, and the latter favoring activation. Because increased Na channel availability may facilitate action potential firing, these results suggest a mechanism for seizure susceptibility of both mice and humans with disrupted beta1 subunits.
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Affiliation(s)
| | | | - Chunling Chen
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
| | - Raffaella Rusconi
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
| | - Emily A. Slat
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan, Ann Arbor, Michigan 48109
| | - Indira M. Raman
- Interdepartmental Neuroscience Program and
- Department of Neurobiology and Physiology, Northwestern University, Evanston, Illinois 60208, and
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39
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Undem BJ, Nassenstein C. Airway nerves and dyspnea associated with inflammatory airway disease. Respir Physiol Neurobiol 2008; 167:36-44. [PMID: 19135556 DOI: 10.1016/j.resp.2008.11.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 11/27/2008] [Accepted: 11/28/2008] [Indexed: 01/28/2023]
Abstract
The neurobiology of dyspnea is varied and complex, but there is little doubt that vagal nerves within the airways are capable of causing or modulating some dyspneic sensations, especially those associated with inflammatory airway diseases. A major contributor to the dyspnea associated with inflammatory airway disease is explained by airway narrowing and increases in the resistance to airflow. The autonomic (parasympathetic) airway nerves directly contribute to this by regulating bronchial smooth muscle tone and mucus secretion. In addition, a component of the information reaching the brainstem via airway mechanosensing and nociceptive afferent nerves likely contributes to the overall sensations of breathing. The airway narrowing can lead to activation of low threshold mechanosensitive stretch receptors, and vagal and spinal C-fibers as well as some rapidly adapting stretch receptor in the airways that are directly activated by various aspects of the inflammatory response. Inflammatory mediators can induce long lasting changes in afferent nerve activity by modulating the expression of key genes. The net effect of the increase in afferent traffic to the brainstem modulates synaptic efficacy at the second-order neurons via various mechanisms collectively referred to as central sensitization. Many studies have shown that stimuli that activate bronchopulmonary afferent nerves can lead to dyspnea in healthy subjects. A logical extension of the basic research on inflammation and sensory nerve function is that the role of vagal sensory nerve in causing or shaping dyspneic sensations will be exaggerated in those suffering from inflammatory airway disease.
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40
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Zhang YH, Chi XX, Nicol GD. Brain-derived neurotrophic factor enhances the excitability of rat sensory neurons through activation of the p75 neurotrophin receptor and the sphingomyelin pathway. J Physiol 2008; 586:3113-27. [PMID: 18450779 DOI: 10.1113/jphysiol.2008.152439] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neurotrophin-mediated signalling cascades can be initiated by activation of either the p75 neurotrophin receptor (p75(NTR)) or the more selective tyrosine kinase receptors. Previously, we demonstrated that nerve growth factor (NGF) increased the excitability of sensory neurons through activation of p75(NTR) to liberate sphingosine 1-phosphate. If neurotrophins can modulate the excitability of small diameter sensory neurons through activation of p75(NTR), then brain-derived neurotrophic factor (BDNF) should produce the same sensitizing action as did NGF. In this report, we show that focally applied BDNF increases the number of action potentials (APs) evoked by a ramp of depolarizing current by reducing the rheobase without altering the firing threshold. This increased excitability results, in part, from the capacity of BDNF to enhance a tetrodotoxin-resistant sodium current (TTX-R I(Na)) and to suppress a delayed rectifier-like potassium current (I(K)). The idea that BDNF acts via p75(NTR) is supported by the following observations. The sensitizing action of BDNF is prevented by pretreatment with a blocking antibody to p75(NTR) or an inhibitor of sphingosine kinase (dimethylsphingosine), but not by inhibitors of tyrosine kinase receptors (K252a or AG879). Furthermore, using single-cell RT-PCR, neurons that were sensitized by BDNF expressed the mRNA for p75(NTR) but not TrkB. These results demonstrate that neurotrophins can modulate the excitability of small diameter capsaicin-sensitive sensory neurons through the activation of p75(NTR) and its downstream sphingomyelin signalling cascade. Neurotrophins released upon activation of a variety of immuno-competent cells may be important mediators that give rise to the enhanced neuronal sensitivity associated with the inflammatory response.
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Affiliation(s)
- Y H Zhang
- Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN 46202, USA
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41
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Sites and molecular mechanisms of modulation of Na(v)1.2 channels by Fyn tyrosine kinase. J Neurosci 2007; 27:11543-51. [PMID: 17959797 DOI: 10.1523/jneurosci.1743-07.2007] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Voltage-gated sodium channels are important targets for modulation of electrical excitability by neurotransmitters and neurotrophins acting through protein phosphorylation. Fast inactivation of Na(V)1.2 channels is regulated via tyrosine phosphorylation by Fyn kinase and dephosphorylation by receptor phosphoprotein tyrosine phosphatase-beta, which are associated in a signaling complex. Here we have identified the amino acid residues on Na(V)1.2 channels that coordinate binding of Fyn kinase and mediate inhibition of sodium currents by enhancing fast inactivation. Fyn kinase binds to a Src homology 3 (SH3)-binding motif in the second half of the intracellular loop connecting domains I and II (L(I-II)) of Na(V)1.2, and mutation of that SH3-binding motif prevents Fyn binding and Fyn enhancement of fast inactivation of sodium currents. Analysis of tyrosine phosphorylation sites by mutagenesis and functional expression revealed a multisite regulatory mechanism. Y66 and Y1893, which are in consensus sequences appropriate for binding to the Fyn SH2 domain after phosphorylation, are both required for optimal binding and regulation by Fyn. Y730, which is located near the SH3-binding motif in L(I-II), and Y1497 and Y1498 in the inactivation gate in L(III-IV), are also required for optimal regulation. Phosphorylation of these sites likely promotes fast inactivation. Fast inactivation of the closely related Na(V)1.1 channels is not modulated by Fyn, and these channels do not contain an SH3-binding motif in L(I-II). Subtype-selective modulation by tyrosine phosphorylation/dephosphorylation provides a mechanism for differential regulation of sodium channels by neurotrophins and tyrosine phosphorylation in unmyelinated axons and dendrites, where Na(V)1.2 channels are expressed in brain neurons.
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