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Francis-Oliveira J, Higa GSV, Viana FJC, Cruvinel E, Carlos-Lima E, da Silva Borges F, Zampieri TT, Rebello FP, Ulrich H, De Pasquale R. TREK-1 inhibition promotes synaptic plasticity in the prelimbic cortex. Exp Neurol 2024; 373:114652. [PMID: 38103709 DOI: 10.1016/j.expneurol.2023.114652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/28/2023] [Accepted: 12/10/2023] [Indexed: 12/19/2023]
Abstract
Synaptic plasticity is one of the putative mechanisms involved in the maturation of the prefrontal cortex (PFC) during postnatal development. Early life stress (ELS) affects the shaping of cortical circuitries through impairment of synaptic plasticity supporting the onset of mood disorders. Growing evidence suggests that dysfunctional postnatal maturation of the prelimbic division (PL) of the PFC might be related to the emergence of depression. The potassium channel TREK-1 has attracted particular interest among many factors that modulate plasticity, concerning synaptic modifications that could underlie mood disorders. Studies have found that ablation of TREK-1 increases the resilience to depression, while rats exposed to ELS exhibit higher TREK-1 levels in the PL. TREK-1 is regulated by multiple intracellular transduction pathways including the ones activated by metabotropic receptors. In the hippocampal neurons, TREK-1 interacts with the serotonergic system, one of the main factors involved in the action of antidepressants. To investigate possible mechanisms related to the antidepressant role of TREK-1, we used brain slice electrophysiology to evaluate the effects of TREK-1 pharmacological blockade on synaptic plasticity at PL circuitry. We extended this investigation to animals subjected to ELS. Our findings suggest that in non-stressed animals, TREK-1 activity is required for the reduction of synaptic responses mediated by the 5HT1A receptor activation. Furthermore, we demonstrate that TREK-1 blockade promotes activity-dependent long-term depression (LTD) when acting in synergy with 5HT1A receptor stimulation. On the other hand, in ELS animals, TREK-1 blockade reduces synaptic transmission and facilitates LTD expression. These results indicate that TREK-1 inhibition stimulates synaptic plasticity in the PL and this effect is more pronounced in animals subjected to ELS during postnatal development.
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Affiliation(s)
- José Francis-Oliveira
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil; Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil; Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, SP 09210-580, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Estevão Carlos-Lima
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernando da Silva Borges
- Department of Physiology & Pharmacology, SUNY Downstate Health Sciences University, Brooklyn, NY 11203, USA
| | - Thais Tessari Zampieri
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Fernanda Pereira Rebello
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), Butantã, SP 05508-900, Brazil
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, SP 05508-000, Brazil.
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Andreyanov M, Heinrich R, Berlin S. Design of Ultrapotent Genetically Encoded Inhibitors of Kv4.2 for Gating Neural Plasticity. J Neurosci 2024; 44:e2295222023. [PMID: 38154956 PMCID: PMC10869153 DOI: 10.1523/jneurosci.2295-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 11/05/2023] [Accepted: 11/22/2023] [Indexed: 12/30/2023] Open
Abstract
The Kv4.2 potassium channel plays established roles in neuronal excitability, while also being implicated in plasticity. Current means to study the roles of Kv4.2 are limited, motivating us to design a genetically encoded membrane tethered Heteropodatoxin-2 (MetaPoda). We find that MetaPoda is an ultrapotent and selective gating-modifier of Kv4.2. We narrow its site of contact with the channel to two adjacent residues within the voltage sensitive domain (VSD) and, with docking simulations, suggest that the toxin binds the VSD from within the membrane. We also show that MetaPoda does not require an external linker of the channel for its activity. In neurons (obtained from female and male rat neonates), MetaPoda specifically, and potently, inhibits all Kv4 currents, leaving all other A-type currents unaffected. Inhibition of Kv4 in hippocampal neurons does not promote excessive excitability, as is expected from a simple potassium channel blocker. We do find that MetaPoda's prolonged expression (1 week) increases expression levels of the immediate early gene cFos and prevents potentiation. These findings argue for a major role of Kv4.2 in facilitating plasticity of hippocampal neurons. Lastly, we show that our engineering strategy is suitable for the swift engineering of another potent Kv4.2-selective membrane-tethered toxin, Phrixotoxin-1, denoted MetaPhix. Together, we provide two uniquely potent genetic tools to study Kv4.2 in neuronal excitability and plasticity.
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Affiliation(s)
- Michael Andreyanov
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
| | - Ronit Heinrich
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
| | - Shai Berlin
- Department of Neuroscience, Ruth and Bruce Rappaport Faculty of Medicine, Technion- Israel Institute of Technology, Haifa 3525433, Israel
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Park HR, Cai M, Yang EJ. Novel Psychopharmacological Herbs Relieve Behavioral Abnormalities and Hippocampal Dysfunctions in an Animal Model of Post-Traumatic Stress Disorder. Nutrients 2023; 15:3815. [PMID: 37686847 PMCID: PMC10490282 DOI: 10.3390/nu15173815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
Post-traumatic stress disorder (PTSD) is an anxiety disorder caused by traumatic or frightening events, with intensified anxiety, fear memories, and cognitive impairment caused by a dysfunctional hippocampus. Owing to its complex phenotype, currently prescribed treatments for PTSD are limited. This study investigated the psychopharmacological effects of novel COMBINATION herbal medicines on the hippocampus of a PTSD murine model induced by combining single prolonged stress (SPS) and foot shock (FS). We designed a novel herbal formula extract (HFE) from Chaenomeles sinensis, Glycyrrhiza uralensis, and Atractylodes macrocephala. SPS+FS mice were administered HFE (500 and 1000 mg/kg) once daily for 14 days. The effects of HFE of HFE on the hippocampus were analyzed using behavioral tests, immunostaining, Golgi staining, and Western blotting. HFE alleviated anxiety-like behavior and fear response, improved short-term memory, and restored hippocampal dysfunction, including hippocampal neurogenesis alteration and aberrant migration and hyperactivation of dentate granule cells in SPS+FS mice. HFE increased phosphorylation of the Kv4.2 potassium channel, extracellular signal-regulated kinase, and cAMP response element-binding protein, which were reduced in the hippocampus of SPS+FS mice. Therefore, our study suggests HFE as a potential therapeutic drug for PTSD by improving behavioral impairment and hippocampal dysfunction and regulating Kv4.2 potassium channel-related pathways in the hippocampus.
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Affiliation(s)
| | | | - Eun Jin Yang
- Department of KM Science Research, Korea Institute of Oriental Medicine (KIOM), Daejeon 34054, Republic of Korea; (H.R.P.); (M.C.)
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Carvalho-Rosa JD, Rodrigues NC, Silva-Cruz A, Vaz SH, Cunha-Reis D. Epileptiform activity influences theta-burst induced LTP in the adult hippocampus: a role for synaptic lipid raft disruption in early metaplasticity? Front Cell Neurosci 2023; 17:1117697. [PMID: 37228704 PMCID: PMC10203237 DOI: 10.3389/fncel.2023.1117697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/13/2023] [Indexed: 05/27/2023] Open
Abstract
Non-epileptic seizures are identified as a common epileptogenic trigger. Early metaplasticity following seizures may contribute to epileptogenesis by abnormally altering synaptic strength and homeostatic plasticity. We now studied how in vitro epileptiform activity (EA) triggers early changes in CA1 long-term potentiation (LTP) induced by theta-burst stimulation (TBS) in rat hippocampal slices and the involvement of lipid rafts in these early metaplasticity events. Two forms of EA were induced: (1) interictal-like EA evoked by Mg2+ withdrawal and K+ elevation to 6 mM in the superfusion medium or (2) ictal-like EA induced by bicuculline (10 μM). Both EA patterns induced and LTP-like effect on CA1 synaptic transmission prior to LTP induction. LTP induced 30 min post EA was impaired, an effect more pronounced after ictal-like EA. LTP recovered to control levels 60 min post interictal-like EA but was still impaired 60 min after ictal-like EA. The synaptic molecular events underlying this altered LTP were investigated 30 min post EA in synaptosomes isolated from these slices. EA enhanced AMPA GluA1 Ser831 phosphorylation but decreased Ser845 phosphorylation and the GluA1/GluA2 ratio. Flotillin-1 and caveolin-1 were markedly decreased concomitantly with a marked increase in gephyrin levels and a less prominent increase in PSD-95. Altogether, EA differentially influences hippocampal CA1 LTP thorough regulation of GluA1/GluA2 levels and AMPA GluA1 phosphorylation suggesting that altered LTP post-seizures is a relevant target for antiepileptogenic therapies. In addition, this metaplasticity is also associated with marked alterations in classic and synaptic lipid raft markers, suggesting these may also constitute promising targets in epileptogenesis prevention.
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Affiliation(s)
- José D. Carvalho-Rosa
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
- BioISI–Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Nádia C. Rodrigues
- Departamento de Química e Bioquímica, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Armando Silva-Cruz
- BioISI–Biosystems and Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa, Lisbon, Portugal
| | - Sandra H. Vaz
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
- Instituto de Farmacologia e Neurociências, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
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5
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Cortical profiles of numerous psychiatric disorders and normal development share a common pattern. Mol Psychiatry 2023; 28:698-709. [PMID: 36380235 DOI: 10.1038/s41380-022-01855-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/16/2022]
Abstract
The neurobiological bases of the association between development and psychopathology remain poorly understood. Here, we identify a shared spatial pattern of cortical thickness (CT) in normative development and several psychiatric and neurological disorders. Principal component analysis (PCA) was applied to CT of 68 regions in the Desikan-Killiany atlas derived from three large-scale datasets comprising a total of 41,075 neurotypical participants. PCA produced a spatially broad first principal component (PC1) that was reproducible across datasets. Then PC1 derived from healthy adult participants was compared to the pattern of CT differences associated with psychiatric and neurological disorders comprising a total of 14,886 cases and 20,962 controls from seven ENIGMA disease-related working groups, normative maturation and aging comprising a total of 17,697 scans from the ABCD Study® and the IMAGEN developmental study, and 17,075 participants from the ENIGMA Lifespan working group, as well as gene expression maps from the Allen Human Brain Atlas. Results revealed substantial spatial correspondences between PC1 and widespread lower CT observed in numerous psychiatric disorders. Moreover, the PC1 pattern was also correlated with the spatial pattern of normative maturation and aging. The transcriptional analysis identified a set of genes including KCNA2, KCNS1 and KCNS2 with expression patterns closely related to the spatial pattern of PC1. The gene category enrichment analysis indicated that the transcriptional correlations of PC1 were enriched to multiple gene ontology categories and were specifically over-represented starting at late childhood, coinciding with the onset of significant cortical maturation and emergence of psychopathology during the prepubertal-to-pubertal transition. Collectively, the present study reports a reproducible latent pattern of CT that captures interregional profiles of cortical changes in both normative brain maturation and a spectrum of psychiatric disorders. The pubertal timing of the expression of PC1-related genes implicates disrupted neurodevelopment in the pathogenesis of the spectrum of psychiatric diseases emerging during adolescence.
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6
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Xiao Z, Zhao P, Wu X, Kong X, Wang R, Liang S, Tang C, Liu Z. Variation of Two S3b Residues in K V4.1-4.3 Channels Underlies Their Different Modulations by Spider Toxin κ-LhTx-1. Front Pharmacol 2021; 12:692076. [PMID: 34177600 PMCID: PMC8222713 DOI: 10.3389/fphar.2021.692076] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 05/27/2021] [Indexed: 11/13/2022] Open
Abstract
The naturally occurred peptide toxins from animal venoms are valuable pharmacological tools in exploring the structure-function relationships of ion channels. Herein we have identified the peptide toxin κ-LhTx-1 from the venom of spider Pandercetes sp (the Lichen huntsman spider) as a novel selective antagonist of the KV4 family potassium channels. κ-LhTx-1 is a gating-modifier toxin impeded KV4 channels' voltage sensor activation, and mutation analysis has confirmed its binding site on channels' S3b region. Interestingly, κ-LhTx-1 differently modulated the gating of KV4 channels, as revealed by toxin inhibiting KV4.2/4.3 with much more stronger voltage-dependence than that for KV4.1. We proposed that κ-LhTx-1 trapped the voltage sensor of KV4.1 in a much more stable resting state than that for KV4.2/4.3 and further explored the underlying mechanism. Swapping the non-conserved S3b segments between KV4.1(280FVPK283) and KV4.3(275VMTN278) fully reversed their voltage-dependence phenotypes in inhibition by κ-LhTx-1, and intensive mutation analysis has identified P282 in KV4.1, D281 in KV4.2 and N278 in KV4.3 being the key residues. Furthermore, the last two residues in this segment of each KV4 channel (P282/K283 in KV4.1, T280/D281 in KV4.2 and T277/N278 in KV4.3) likely worked synergistically as revealed by our combinatorial mutations analysis. The present study has clarified the molecular basis in KV4 channels for their different modulations by κ-LhTx-1, which have advanced our understanding on KV4 channels' structure features. Moreover, κ-LhTx-1 might be useful in developing anti-arrhythmic drugs given its high affinity, high selectivity and unique action mode in interacting with the KV4.2/4.3 channels.
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Affiliation(s)
- Zhen Xiao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Piao Zhao
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiangyue Wu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Xiangjin Kong
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Ruiwen Wang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Songping Liang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Cheng Tang
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
| | - Zhonghua Liu
- The National and Local Joint Engineering Laboratory of Animal Peptide Drug Development, College of Life Sciences, Hunan Normal University, Changsha, China
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7
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The Na +-activated K + channel Slack contributes to synaptic development and plasticity. Cell Mol Life Sci 2021; 78:7569-7587. [PMID: 34664085 PMCID: PMC8629810 DOI: 10.1007/s00018-021-03953-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 09/08/2021] [Accepted: 09/22/2021] [Indexed: 11/29/2022]
Abstract
Human mutations of the Na+-activated K+ channel Slack (KCNT1) are associated with epilepsy and intellectual disability. Accordingly, Slack knockout mice (Slack-/-) exhibit cognitive flexibility deficits in distinct behavioral tasks. So far, however, the underlying causes as well as the role of Slack in hippocampus-dependent memory functions remain enigmatic. We now report that infant (P6-P14) Slack-/- lack both hippocampal LTD and LTP, likely due to impaired NMDA receptor (NMDAR) signaling. Postsynaptic GluN2B levels are reduced in infant Slack-/-, evidenced by lower amplitudes of NMDAR-meditated excitatory postsynaptic potentials. Low GluN2B affected NMDAR-mediated Ca2+-influx, rendering cultured hippocampal Slack-/-neurons highly insensitive to the GluN2B-specific inhibitor Ro 25-6981. Furthermore, dephosphorylation of the AMPA receptor (AMPAR) subunit GluA1 at S845, which is involved in AMPAR endocytosis during homeostatic and neuromodulator-regulated plasticity, is reduced after chemical LTD (cLTD) in infant Slack-/-. We additionally detect a lack of mGluR-induced LTD in infant Slack-/-, possibly caused by upregulation of the recycling endosome-associated small GTPase Rab4 which might accelerate AMPAR recycling from early endosomes. Interestingly, LTP and mGluR LTD, but not LTD and S845 dephosphorylation after cLTD are restored in adult Slack-/-. This together with normalized expression levels of GluN2B and Rab4 hints to developmental "restoration" of LTP expression despite Slack ablation, whereas in infant and adult brain, NMDAR-dependent LTD induction depends on this channel. Based on the present findings, NMDAR and vesicular transport might represent novel targets for the therapy of intellectual disability associated with Slack mutations. Consequently, careful modulation of hippocampal Slack activity should also improve learning abilities.
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8
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Aceto G, Re A, Mattera A, Leone L, Colussi C, Rinaudo M, Scala F, Gironi K, Barbati SA, Fusco S, Green T, Laezza F, D'Ascenzo M, Grassi C. GSK3β Modulates Timing-Dependent Long-Term Depression Through Direct Phosphorylation of Kv4.2 Channels. Cereb Cortex 2020; 29:1851-1865. [PMID: 29790931 DOI: 10.1093/cercor/bhy042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/15/2018] [Accepted: 02/07/2018] [Indexed: 12/31/2022] Open
Abstract
Spike timing-dependent plasticity (STDP) is a form of activity-dependent remodeling of synaptic strength that underlies memory formation. Despite its key role in dictating learning rules in the brain circuits, the molecular mechanisms mediating STDP are still poorly understood. Here, we show that spike timing-dependent long-term depression (tLTD) and A-type K+ currents are modulated by pharmacological agents affecting the levels of active glycogen-synthase kinase 3 (GSK3) and by GSK3β knockdown in layer 2/3 of the mouse somatosensory cortex. Moreover, the blockade of A-type K+ currents mimics the effects of GSK3 up-regulation on tLTD and occludes further changes in synaptic strength. Pharmacological, immunohistochemical and biochemical experiments revealed that GSK3β influence over tLTD induction is mediated by direct phosphorylation at Ser-616 of the Kv4.2 subunit, a molecular determinant of A-type K+ currents. Collectively, these results identify the functional interaction between GSK3β and Kv4.2 channel as a novel mechanism for tLTD modulation providing exciting insight into the understanding of GSK3β role in synaptic plasticity.
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Affiliation(s)
- Giuseppe Aceto
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Agnese Re
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Andrea Mattera
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Lucia Leone
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Claudia Colussi
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Marco Rinaudo
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Federico Scala
- Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Katia Gironi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy
| | | | - Salvatore Fusco
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Thomas Green
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Fernanda Laezza
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, USA
| | - Marcello D'Ascenzo
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
| | - Claudio Grassi
- Institute of Human Physiology, Università Cattolica del Sacro Cuore, Rome, Italy.,Fondazione Policlinico Universitario A Gemelli, IRCCS, Rome, Italy
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Chittajallu R, Auville K, Mahadevan V, Lai M, Hunt S, Calvigioni D, Pelkey KA, Zaghloul KA, McBain CJ. Activity-dependent tuning of intrinsic excitability in mouse and human neurogliaform cells. eLife 2020; 9:57571. [PMID: 32496194 PMCID: PMC7299336 DOI: 10.7554/elife.57571] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Accepted: 06/02/2020] [Indexed: 12/15/2022] Open
Abstract
The ability to modulate the efficacy of synaptic communication between neurons constitutes an essential property critical for normal brain function. Animal models have proved invaluable in revealing a wealth of diverse cellular mechanisms underlying varied plasticity modes. However, to what extent these processes are mirrored in humans is largely uncharted thus questioning their relevance in human circuit function. In this study, we focus on neurogliaform cells, that possess specialized physiological features enabling them to impart a widespread inhibitory influence on neural activity. We demonstrate that this prominent neuronal subtype, embedded in both mouse and human neural circuits, undergo remarkably similar activity-dependent modulation manifesting as epochs of enhanced intrinsic excitability. In principle, these evolutionary conserved plasticity routes likely tune the extent of neurogliaform cell mediated inhibition thus constituting canonical circuit mechanisms underlying human cognitive processing and behavior.
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Affiliation(s)
- Ramesh Chittajallu
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Kurt Auville
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Vivek Mahadevan
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Mandy Lai
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Steven Hunt
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Daniela Calvigioni
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Kenneth A Pelkey
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
| | - Kareem A Zaghloul
- Surgical Neurology Branch, National Institutes of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, United States
| | - Chris J McBain
- Laboratory of Cellular and Synaptic Physiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, United States
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10
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Fernández-Fernández D, Lamas JA. Metabotropic Modulation of Potassium Channels During Synaptic Plasticity. Neuroscience 2020; 456:4-16. [PMID: 32114098 DOI: 10.1016/j.neuroscience.2020.02.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 02/14/2020] [Accepted: 02/18/2020] [Indexed: 01/06/2023]
Abstract
Besides their primary function mediating the repolarization phase of action potentials, potassium channels exquisitely and ubiquitously regulate the resting membrane potential of neurons and therefore have a key role establishing their intrinsic excitability. This group of proteins is composed of a very diverse collection of voltage-dependent and -independent ion channels, whose specific distribution is finely tuned at the level of the synapse. Both at the presynaptic and postsynaptic membranes, different types of potassium channels are subjected to modulation by second messenger signaling cascades triggered by metabotropic receptors, which in this way serve as a link between neurotransmitter actions and changes in the neuron membrane excitability. On the one hand, by regulating the resting membrane potential of the postsynaptic membrane, potassium channels appear to be critical towards setting the threshold for the induction of long-term potentiation and depression. On the other hand, these channels maintain the presynaptic membrane potential under control, therefore influencing the probability of neurotransmitter release underlying different forms of short-term plasticity. In the present review, we examine in detail the role of metabotropic receptors translating their activation by different neurotransmitters into a final effect modulating several types of potassium channels. Furthermore, we evaluate the consequences that this interplay has on the induction and maintenance of different forms of synaptic plasticity.
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Affiliation(s)
- D Fernández-Fernández
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain.
| | - J A Lamas
- Laboratory of Neuroscience, Biomedical Research Center (CINBIO), University of Vigo, Vigo, Galicia, Spain
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11
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Shrestha A, Sultana R, Lee CC, Ogundele OM. SK Channel Modulates Synaptic Plasticity by Tuning CaMKIIα/β Dynamics. Front Synaptic Neurosci 2019; 11:18. [PMID: 31736736 PMCID: PMC6834780 DOI: 10.3389/fnsyn.2019.00018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 05/20/2019] [Indexed: 11/13/2022] Open
Abstract
N-Methyl-D-Aspartate Receptor 1 (NMDAR)-linked Ca++ current represents a significant percentage of post-synaptic transient that modulates synaptic strength and is pertinent to dendritic spine plasticity. In the hippocampus, Ca++ transient produced by glutamatergic ionotropic neurotransmission facilitates Ca++-Calmodulin-dependent kinase 2 (CaMKII) Thr286 phosphorylation and promote long-term potentiation (LTP) expression. At CA1 post-synaptic densities, Ca++ transients equally activate small conductance (SK2) channel which regulates excitability by suppressing Ca++ movement. Here, we demonstrate that upstream attenuation of GluN1 function in the hippocampus led to a decrease in Thr286 CaMKIIα phosphorylation, and increased SK2 expression. Consistent with the loss of GluN1 function, potentiation of SK channel in wild type hippocampus reduced CaMKIIα expression and abrogate synaptic localization of T286 pCaMKIIα. Our results demonstrate that positive modulation of SK channel at hippocampal synapses likely refine GluN1-linked plasticity by tuning dendritic localization of CaMKIIα.
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Affiliation(s)
| | | | | | - Olalekan M. Ogundele
- Department of Comparative Biomedical Sciences, Louisiana State University School of Veterinary Medicine, Baton Rouge, LA, United States
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12
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Tabor GT, Park JM, Murphy JG, Hu JH, Hoffman DA. A novel bungarotoxin binding site-tagged construct reveals MAPK-dependent Kv4.2 trafficking. Mol Cell Neurosci 2019; 98:121-130. [PMID: 31212013 DOI: 10.1016/j.mcn.2019.06.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 02/07/2023] Open
Abstract
Kv4.2 voltage-gated K+ channel subunits, the primary source of the somatodendritic A-type K+ current in CA1 pyramidal neurons of the hippocampus, play important roles in regulating dendritic excitability and plasticity. To better study the trafficking and subcellular distribution of Kv4.2, we created and characterized a novel Kv4.2 construct encoding a bungarotoxin binding site in the extracellular S3-S4 linker region of the α-subunit. When expressed, this construct can be visualized in living cells after staining with rhodamine-conjugated bungarotoxin. We validated the utility of this construct by visualizing the spontaneous internalization and insertion of Kv4.2 in HEK 293T cells. We further report that Kv4.2 colocalized with several endosome markers in HEK 293T cells. In addition, Kv4.2 internalization is significantly impaired by mitogen-activated protein kinase (MAPK) inhibitors in transfected primary hippocampal neurons. Therefore, this newly developed BBS-Kv4.2 construct provides a novel and powerful tool for studying surface Kv4.2 channel localization and trafficking.
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Affiliation(s)
- G Travis Tabor
- Section on Molecular Neurophysiology & Biophysics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, United States of America
| | - Jung M Park
- Section on Molecular Neurophysiology & Biophysics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, United States of America
| | - Jonathan G Murphy
- Section on Molecular Neurophysiology & Biophysics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, United States of America; National Institute of General Medical Sciences, NIH, Bethesda, MD 20892, United States of America
| | - Jia-Hua Hu
- Section on Molecular Neurophysiology & Biophysics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, United States of America.
| | - Dax A Hoffman
- Section on Molecular Neurophysiology & Biophysics, The Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892, United States of America.
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13
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Noh W, Pak S, Choi G, Yang S, Yang S. Transient Potassium Channels: Therapeutic Targets for Brain Disorders. Front Cell Neurosci 2019; 13:265. [PMID: 31263403 PMCID: PMC6585177 DOI: 10.3389/fncel.2019.00265] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 05/28/2019] [Indexed: 01/04/2023] Open
Abstract
Transient potassium current channels (IA channels), which are expressed in most brain areas, have a central role in modulating feedforward and feedback inhibition along the dendroaxonic axis. Loss of the modulatory channels is tightly associated with a number of brain diseases such as Alzheimer’s disease, epilepsy, fragile X syndrome (FXS), Parkinson’s disease, chronic pain, tinnitus, and ataxia. However, the functional significance of IA channels in these diseases has so far been underestimated. In this review, we discuss the distribution and function of IA channels. Particularly, we posit that downregulation of IA channels results in neuronal (mostly dendritic) hyperexcitability accompanied by the imbalanced excitation and inhibition ratio in the brain’s networks, eventually causing the brain diseases. Finally, we propose a potential therapeutic target: the enhanced action of IA channels to counteract Ca2+-permeable channels including NMDA receptors could be harnessed to restore dendritic excitability, leading to a balanced neuronal state.
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Affiliation(s)
- Wonjun Noh
- Department of Nano-Bioengineering, Incheon National University, Incheon, South Korea
| | - Sojeong Pak
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Geunho Choi
- Department of Computer Science and Engineering, Incheon National University, Incheon, South Korea
| | - Sungchil Yang
- Department of Biomedical Sciences, City University of Hong Kong, Kowloon, Hong Kong
| | - Sunggu Yang
- Department of Nano-Bioengineering, Incheon National University, Incheon, South Korea
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14
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Johnson GC, May V, Parsons RL, Hammack SE. Parallel signaling pathways of pituitary adenylate cyclase activating polypeptide (PACAP) regulate several intrinsic ion channels. Ann N Y Acad Sci 2019; 1455:105-112. [PMID: 31162688 DOI: 10.1111/nyas.14116] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/27/2019] [Accepted: 04/12/2019] [Indexed: 12/01/2022]
Abstract
Pituitary adenylate cyclase activating polypeptide (PACAP), acting through its cognate receptors PAC1, VPAC1, and VPAC2, is a pleiotropic signaling neuropeptide of the vasoactive intestinal peptide/secretin/glucagon family. PACAP has known functions in neuronal growth, development, and repair, and central PACAP signaling has acute behavioral consequences. One of the ways in which PACAP may affect neuronal function is through the modulation of intrinsic membrane currents to control neuronal excitability. Here, we review the evidence of PACAP-dependent modulation of calcium- and voltage-gated potassium currents, hyperpolarization-activated cation currents, calcium currents, and voltage-gated sodium currents. Interestingly, PACAP signaling pathways diverge into parallel pathways to target different ionic currents for modulation, though single pathways are not limited to modulating just one target ionic current. Despite the various targets of modulation, the weight of the evidence suggests that PACAP signaling most commonly leads to a net increase in neuronal excitability. We discuss possible mechanisms by which PACAP signaling leads to the modulation of intrinsic membrane currents that may contribute to changes in behavior.
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Affiliation(s)
- Gregory C Johnson
- Department of Psychological Science, University of Vermont, Burlington, Vermont
| | - Victor May
- Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Rodney L Parsons
- Neurological Sciences, University of Vermont, Burlington, Vermont
| | - Sayamwong E Hammack
- Department of Psychological Science, University of Vermont, Burlington, Vermont
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15
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Zemel BM, Ritter DM, Covarrubias M, Muqeem T. A-Type K V Channels in Dorsal Root Ganglion Neurons: Diversity, Function, and Dysfunction. Front Mol Neurosci 2018; 11:253. [PMID: 30127716 PMCID: PMC6088260 DOI: 10.3389/fnmol.2018.00253] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 07/04/2018] [Indexed: 12/13/2022] Open
Abstract
A-type voltage-gated potassium (Kv) channels are major regulators of neuronal excitability that have been mainly characterized in the central nervous system. By contrast, there is a paucity of knowledge about the molecular physiology of these Kv channels in the peripheral nervous system, including highly specialized and heterogenous dorsal root ganglion (DRG) neurons. Although all A-type Kv channels display pore-forming subunits with similar structural properties and fast inactivation, their voltage-, and time-dependent properties and modulation are significantly different. These differences ultimately determine distinct physiological roles of diverse A-type Kv channels, and how their dysfunction might contribute to neurological disorders. The importance of A-type Kv channels in DRG neurons is highlighted by recent studies that have linked their dysfunction to persistent pain sensitization. Here, we review the molecular neurophysiology of A-type Kv channels with an emphasis on those that have been identified and investigated in DRG nociceptors (Kv1.4, Kv3.4, and Kv4s). Also, we discuss evidence implicating these Kv channels in neuropathic pain resulting from injury, and present a perspective of outstanding challenges that must be tackled in order to discover novel treatments for intractable pain disorders.
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Affiliation(s)
- Benjamin M. Zemel
- Vollum Institute, Oregon Health and Science University, Portland, OR, United States
| | - David M. Ritter
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States
| | - Manuel Covarrubias
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
| | - Tanziyah Muqeem
- Department of Neuroscience, Vickie and Jack Farber Institute for Neuroscience, Sidney Kimmel Medical College and Jefferson College of Life Sciences at Thomas Jefferson University, Philadelphia, PA, United States
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16
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Ogundele OM, Pardo J, Francis J, Goya RG, Lee CC. A Putative Mechanism of Age-Related Synaptic Dysfunction Based on the Impact of IGF-1 Receptor Signaling on Synaptic CaMKIIα Phosphorylation. Front Neuroanat 2018; 12:35. [PMID: 29867375 PMCID: PMC5960681 DOI: 10.3389/fnana.2018.00035] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 04/18/2018] [Indexed: 01/13/2023] Open
Abstract
Insulin-like growth factor 1 receptor (IGF-1R) signaling regulates the activity and phosphorylation of downstream kinases linked to inflammation, neurodevelopment, aging and synaptic function. In addition to the control of Ca2+ currents, IGF-1R signaling modulates the activity of calcium-calmodulin-dependent kinase 2 alpha (CaMKIIα) and mitogen activated protein kinase (MAPK/ErK) through multiple signaling pathways. These proteins (CaMKIIα and MAPK) regulate Ca2+ movement and long-term potentiation (LTP). Since IGF-1R controls the synaptic activity of Ca2+, CaMKIIα and MAPK signaling, the possible mechanism through which an age-dependent change in IGF-1R can alter the synaptic expression and phosphorylation of these proteins in aging needs to be investigated. In this study, we evaluated the relationship between an age-dependent change in brain IGF-1R and phosphorylation of CaMKIIα/MAPK. Furthermore, we elucidated possible mechanisms through which dysregulated CaMKIIα/MAPK interaction may be linked to a change in neurotransmitter processing and synaptic function. Male C57BL/6 VGAT-Venus mice at postnatal days 80 (P80), 365 and 730 were used to study age-related neural changes in two brain regions associated with cognitive function: hippocampus and prefrontal cortex (PFC). By means of high throughput confocal imaging and quantitative immunoblotting, we evaluated the distribution and expression of IGF-1, IGF-1R, CaMKIIα, p-CaMKIIα, MAPK and p-MAPK in whole brain lysate, hippocampus and cortex. Furthermore, we compared protein expression patterns and regional changes at P80, P365 and P730. Ultimately, we determined the relative phosphorylation pattern of CaMKIIα and MAPK through quantification of neural p-CaMKIIα and p-MAPK/ErK, and IGF-1R expression for P80, P365 and P730 brain samples. In addition to a change in synaptic function, our results show a decrease in neural IGF-1/IGF-1R expression in whole brain, hippocampus and cortex of aged mice. This was associated with a significant upregulation of phosphorylated neural MAPK (p-MAPK) and decrease in total brain CaMKIIα (i.e., CaMKIIα and p-CaMKIIα) in the aged brain. Taken together, we showed that brain aging is associated with a change in neural IGF-1/IGF-1R expression and may be linked to a change in phosphorylation of synaptic kinases (CaMKIIα and MAPK) that are involved in the modulation of LTP.
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Affiliation(s)
- Olalekan M. Ogundele
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
| | - Joaquin Pardo
- Institute for Biochemical Research of La Plata, School of Medicine, National University of La Plata, La Plata, Argentina
| | - Joseph Francis
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
| | - Rodolfo G. Goya
- Institute for Biochemical Research of La Plata, School of Medicine, National University of La Plata, La Plata, Argentina
| | - Charles C. Lee
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, United States
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17
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Akita T, Aoto K, Kato M, Shiina M, Mutoh H, Nakashima M, Kuki I, Okazaki S, Magara S, Shiihara T, Yokochi K, Aiba K, Tohyama J, Ohba C, Miyatake S, Miyake N, Ogata K, Fukuda A, Matsumoto N, Saitsu H. De novo variants in CAMK2A and CAMK2B cause neurodevelopmental disorders. Ann Clin Transl Neurol 2018; 5:280-296. [PMID: 29560374 PMCID: PMC5846454 DOI: 10.1002/acn3.528] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 12/15/2017] [Indexed: 11/29/2022] Open
Abstract
Objective α (CAMK2A) and β (CAMK2B) isoforms of Calcium/calmodulin‐dependent protein kinase II (CaMKII) play a pivotal role in neuronal plasticity and in learning and memory processes in the brain. Here, we explore the possible involvement of α‐ and β‐CaMKII variants in neurodevelopmental disorders. Methods Whole‐exome sequencing was performed for 976 individuals with intellectual disability, developmental delay, and epilepsy. The effect of CAMK2A and CAMK2B variants on CaMKII structure and firing of neurons was evaluated by computational structural analysis, immunoblotting, and electrophysiological analysis. Results We identified a total of five de novo CAMK2A and CAMK2B variants in three and two individuals, respectively. Seizures were common to three individuals with CAMK2A variants. Using a minigene splicing assay, we demonstrated that a splice site variant caused skipping of exon 11 leading to an in‐frame deletion of the regulatory segment of CaMKIIα. By structural analysis, four missense variants are predicted to impair the interaction between the kinase domain and the regulatory segment responsible for the autoinhibition of its kinase activity. The Thr286/Thr287 phosphorylation as a result of release from autoinhibition was increased in three mutants when the mutants were stably expressed in Neuro‐2a neuroblastoma cells. Expression of a CaMKIIα mutant in primary hippocampal neurons significantly increased A‐type K+ currents, which facilitated spike repolarization of single action potentials. Interpretation Our data highlight the importance of CaMKIIα and CaMKIIβ and their autoinhibitory regulation in human brain function, and suggest the enhancement of A‐type K+ currents as a possible pathophysiological basis.
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Affiliation(s)
- Tenpei Akita
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Kazushi Aoto
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuhiro Kato
- Department of Pediatrics Showa University School of Medicine 1-5-8 Hatanodai, Shinagawa-ku Tokyo 142-8666 Japan
| | - Masaaki Shiina
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hiroki Mutoh
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Mitsuko Nakashima
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan.,Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Ichiro Kuki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shin Okazaki
- Department of Pediatric Neurology Pediatric Medical Care Center Osaka City General Hospital 2-13-22 Miyakojimahondori, Miyakojima-ku Osaka 534-0021 Japan
| | - Shinichi Magara
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Takashi Shiihara
- Department of Neurology Gunma Children's Medical Center 779 Shimohakoda, Hokkitsu-machi Shibukawa Gunma 377-8577 Japan
| | - Kenji Yokochi
- Department of Pediatric Neurology Seirei-Mikatahara General Hospital 3453 Mikatahara-cho, Kita-ku Hamamatsu 433-8558 Japan.,Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Kaori Aiba
- Department of Pediatrics Toyohashi Municipal Hospital, Toyohashi 50 Hachikennishi, Aotake-cho Toyohashi 441-8570 Japan
| | - Jun Tohyama
- Department of Pediatrics Epilepsy Center Nishi-Niigata Chuo National Hospital 1-14-1 Masago, Nishi-ku Niigata 950-2085 Japan
| | - Chihiro Ohba
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Satoko Miyatake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Noriko Miyake
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Kazuhiro Ogata
- Department of Biochemistry Yokohama City University Graduate School of Medicine 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Atsuo Fukuda
- Department of Neurophysiology Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
| | - Naomichi Matsumoto
- Department of Human Genetics Graduate School of Medicine Yokohama City University 3-9 Fukuura, Kanazawa-ku Yokohama 236-0004 Japan
| | - Hirotomo Saitsu
- Department of Biochemistry Hamamatsu University School of Medicine 1-20-1 Handayama, Higashi-ku Hamamatsu 431-3192 Japan
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18
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Wild AR, Dell'Acqua ML. Potential for therapeutic targeting of AKAP signaling complexes in nervous system disorders. Pharmacol Ther 2017; 185:99-121. [PMID: 29262295 DOI: 10.1016/j.pharmthera.2017.12.004] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
A common feature of neurological and neuropsychiatric disorders is a breakdown in the integrity of intracellular signal transduction pathways. Dysregulation of ion channels and receptors in the cell membrane and the enzymatic mediators that link them to intracellular effectors can lead to synaptic dysfunction and neuronal death. However, therapeutic targeting of these ubiquitous signaling elements can lead to off-target side effects due to their widespread expression in multiple systems of the body. A-kinase anchoring proteins (AKAPs) are multivalent scaffolding proteins that compartmentalize a diverse range of receptor and effector proteins to streamline signaling within nanodomain signalosomes. A number of essential neurological processes are known to critically depend on AKAP-directed signaling and an understanding of the role AKAPs play in nervous system disorders has emerged in recent years. Selective targeting of AKAP protein-protein interactions may be a means to uncouple pathologically active signaling pathways in neurological disorders with a greater degree of specificity. In this review we will discuss the role of AKAPs in both regulating normal nervous system function and dysfunction associated with disease, and the potential for therapeutic targeting of AKAP signaling complexes.
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Affiliation(s)
- Angela R Wild
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Aurora, CO 80045, USA.
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19
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Almonte AG, Ewin SE, Mauterer MI, Morgan JW, Carter ES, Weiner JL. Enhanced ventral hippocampal synaptic transmission and impaired synaptic plasticity in a rodent model of alcohol addiction vulnerability. Sci Rep 2017; 7:12300. [PMID: 28951619 PMCID: PMC5615051 DOI: 10.1038/s41598-017-12531-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2016] [Accepted: 09/12/2017] [Indexed: 02/06/2023] Open
Abstract
It has long been appreciated that adolescence represents a uniquely vulnerable period when chronic exposure to stressors can precipitate the onset of a broad spectrum of psychiatric disorders and addiction in adulthood. However, the neurobiological substrates and the full repertoire of adaptations within these substrates making adolescence a particularly susceptible developmental stage are not well understood. Prior work has demonstrated that a rodent model of adolescent social isolation (aSI) produces robust and persistent increases in phenotypes relevant to anxiety/stressor disorders and alcohol addiction, including anxiogenesis, deficits in fear extinction, and increased ethanol consumption. Here, we used extracellular field recordings in hippocampal slices to investigate adaptations in synaptic function and synaptic plasticity arising from aSI. We demonstrate that this early life stressor leads to enhanced excitatory synaptic transmission and decreased levels of long-term potentiation at hippocampal Schaffer collateral-CA1 synapses. Further, these changes were largely confined to the ventral hippocampus. As the ventral hippocampus is integral to neurocircuitry that mediates emotional behaviors, our results add to mounting evidence that aSI has profound effects on brain areas that regulate affective states. These studies also lend additional support to our recent proposal of the aSI model as a valid model of alcohol addiction vulnerability.
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Affiliation(s)
- Antoine G Almonte
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Sarah E Ewin
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Madelyn I Mauterer
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - James W Morgan
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Eugenia S Carter
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA
| | - Jeffrey L Weiner
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC, 27157, USA.
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20
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Yang YS, Jeon SC, Kang MS, Kim SH, Eun SY, Jin SH, Jung SC. Activation of ryanodine receptors is required for PKA-mediated downregulation of A-type K+channels in rat hippocampal neurons. J Neurosci Res 2017; 95:2469-2482. [DOI: 10.1002/jnr.24076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Revised: 04/07/2017] [Accepted: 04/10/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Yoon-Sil Yang
- Department of Physiology, School of Medicine
- Department of Structure and Function of Neural Network; Korea Brain Research Institute; 41068, Daegu Republic of Korea
| | | | | | | | - Su-Yong Eun
- Department of Physiology, School of Medicine
| | - Soo-Hee Jin
- Department of Preventive Medicine; School of Medicine, Kyungpook National University; 41566
| | - Sung-Cherl Jung
- Department of Physiology, School of Medicine
- Institute of Medical Science, Jeju National University, 63243; Jeju
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21
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Synaptic plasticity in dendrites: complications and coping strategies. Curr Opin Neurobiol 2017; 43:177-186. [PMID: 28453975 DOI: 10.1016/j.conb.2017.03.012] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Revised: 03/20/2017] [Accepted: 03/22/2017] [Indexed: 12/15/2022]
Abstract
The elaborate morphology, nonlinear membrane mechanisms and spatiotemporally varying synaptic activation patterns of dendrites complicate the expression, compartmentalization and modulation of synaptic plasticity. To grapple with this complexity, we start with the observation that neurons in different brain areas face markedly different learning problems, and dendrites of different neuron types contribute to the cell's input-output function in markedly different ways. By committing to specific assumptions regarding a neuron's learning problem and its input-output function, specific inferences can be drawn regarding the synaptic plasticity mechanisms and outcomes that we 'ought' to expect for that neuron. Exploiting this assumption-driven approach can help both in interpreting existing experimental data and designing future experiments aimed at understanding the brain's myriad learning processes.
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22
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Duménieu M, Oulé M, Kreutz MR, Lopez-Rojas J. The Segregated Expression of Voltage-Gated Potassium and Sodium Channels in Neuronal Membranes: Functional Implications and Regulatory Mechanisms. Front Cell Neurosci 2017; 11:115. [PMID: 28484374 PMCID: PMC5403416 DOI: 10.3389/fncel.2017.00115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 04/05/2017] [Indexed: 01/25/2023] Open
Abstract
Neurons are highly polarized cells with apparent functional and morphological differences between dendrites and axon. A critical determinant for the molecular and functional identity of axonal and dendritic segments is the restricted expression of voltage-gated ion channels (VGCs). Several studies show an uneven distribution of ion channels and their differential regulation within dendrites and axons, which is a prerequisite for an appropriate integration of synaptic inputs and the generation of adequate action potential (AP) firing patterns. This review article will focus on the signaling pathways leading to segmented expression of voltage-gated potassium and sodium ion channels at the neuronal plasma membrane and the regulatory mechanisms ensuring segregated functions. We will also discuss the relevance of proper ion channel targeting for neuronal physiology and how alterations in polarized distribution contribute to neuronal pathology.
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Affiliation(s)
- Maël Duménieu
- Research Group Neuroplasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
| | - Marie Oulé
- Research Group Neuroplasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
| | - Michael R Kreutz
- Research Group Neuroplasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany.,Leibniz Group "Dendritic Organelles and Synaptic Function", University Medical Center Hamburg-Eppendorf, Center for Molecular Neurobiology (ZMNH)Hamburg, Germany
| | - Jeffrey Lopez-Rojas
- Research Group Neuroplasticity, Leibniz Institute for NeurobiologyMagdeburg, Germany
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23
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Sandler M, Shulman Y, Schiller J. A Novel Form of Local Plasticity in Tuft Dendrites of Neocortical Somatosensory Layer 5 Pyramidal Neurons. Neuron 2016; 90:1028-42. [DOI: 10.1016/j.neuron.2016.04.032] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Revised: 03/24/2016] [Accepted: 04/07/2016] [Indexed: 11/28/2022]
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O'Dell TJ, Connor SA, Guglietta R, Nguyen PV. β-Adrenergic receptor signaling and modulation of long-term potentiation in the mammalian hippocampus. ACTA ACUST UNITED AC 2015; 22:461-71. [PMID: 26286656 PMCID: PMC4561407 DOI: 10.1101/lm.031088.113] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 06/02/2015] [Indexed: 02/06/2023]
Abstract
Encoding new information in the brain requires changes in synaptic strength. Neuromodulatory transmitters can facilitate synaptic plasticity by modifying the actions and expression of specific signaling cascades, transmitter receptors and their associated signaling complexes, genes, and effector proteins. One critical neuromodulator in the mammalian brain is norepinephrine (NE), which regulates multiple brain functions such as attention, perception, arousal, sleep, learning, and memory. The mammalian hippocampus receives noradrenergic innervation and hippocampal neurons express β-adrenergic receptors, which are known to play important roles in gating the induction of long-lasting forms of synaptic potentiation. These forms of long-term potentiation (LTP) are believed to importantly contribute to long-term storage of spatial and contextual memories in the brain. In this review, we highlight the contributions of noradrenergic signaling in general and β-adrenergic receptors in particular, toward modulating hippocampal LTP. We focus on the roles of NE and β-adrenergic receptors in altering the efficacies of specific signaling molecules such as NMDA and AMPA receptors, protein phosphatases, and translation initiation factors. Also, the roles of β-adrenergic receptors in regulating synaptic "tagging" and "capture" of LTP within synaptic networks of the hippocampus are reviewed. Understanding the molecular and cellular bases of noradrenergic signaling will enrich our grasp of how the brain makes new, enduring memories, and may shed light on credible strategies for improving mental health through treatment of specific disorders linked to perturbed memory processing and dysfunctional noradrenergic synaptic transmission.
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Affiliation(s)
- Thomas J O'Dell
- Department of Physiology, David Geffen School of Medicine and Integrative Center for Learning and Memory, Brain Research Institute, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Steven A Connor
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
| | - Ryan Guglietta
- Interdepartmental Ph.D. Program for Neuroscience, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Peter V Nguyen
- Department of Physiology, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Department of Psychiatry, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada Department of Neuroscience & Mental Health Institute, University of Alberta School of Medicine, Edmonton, Alberta T6G 2H7, Canada
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Bitencourt RM, Alpár A, Cinquina V, Ferreira SG, Pinheiro BS, Lemos C, Ledent C, Takahashi RN, Sialana FJ, Lubec G, Cunha RA, Harkany T, Köfalvi A. Lack of presynaptic interaction between glucocorticoid and CB1 cannabinoid receptors in GABA- and glutamatergic terminals in the frontal cortex of laboratory rodents. Neurochem Int 2015. [PMID: 26196379 DOI: 10.1016/j.neuint.2015.07.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Corticosteroid and endocannabinoid actions converge on prefrontocortical circuits associated with neuropsychiatric illnesses. Corticosteroids can also modulate forebrain synapses by using endocannabinoid effector systems. Here, we determined whether corticosteroids can modulate transmitter release directly in the frontal cortex and, in doing so, whether they affect presynaptic CB1 cannabinoid receptor- (CB1R) mediated neuromodulation. By Western blotting of purified subcellular fractions of the rat frontal cortex, we found glucocorticoid receptors (GcRs) and CB1Rs enriched in isolated frontocortical nerve terminals (synaptosomes). CB1Rs were predominantly presynaptically located while GcRs showed preference for the post-synaptic fraction. Additional confocal microscopy analysis of cortical and hippocampal regions revealed vesicular GABA transporter-positive and vesicular glutamate transporter 1-positive nerve terminals endowed with CB1R immunoreactivity, apposing GcR-positive post-synaptic compartments. In functional transmitter release assay, corticosteroids, corticosterone (0.1-10 microM) and dexamethasone (0.1-10 microM) did not significantly affect the evoked release of [(3)H]GABA and [(14)C]glutamate in superfused synaptosomes, isolated from both rats and mice. In contrast, the synthetic cannabinoid, WIN55212-2 (1 microM) diminished the release of both [(3)H]GABA and [(14)C]glutamate, evoked with various depolarization paradigms. This effect of WIN55212-2 was abolished by the CB1R neutral antagonist, O-2050 (1 microM), and was absent in the CB1R KO mice. CB2R-selective agonists did not affect the release of either neurotransmitter. The lack of robust presynaptic neuromodulation by corticosteroids was unchanged upon either CB1R activation or genetic inactivation. Altogether, corticosteroids are unlikely to exert direct non-genomic presynaptic neuromodulation in the frontal cortex, but they may do so indirectly, via the stimulation of trans-synaptic endocannabinoid signaling.
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Affiliation(s)
- Rafael M Bitencourt
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; Laboratory of Psychopharmacology, Dept. Pharmacology, Universidade Federal de Santa Catarina, Florianopolis 88049-900, Brazil
| | - Alán Alpár
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden
| | - Valentina Cinquina
- Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria; University of Insubria, Via Ravasi, 2, 21100 Varese, Italy
| | - Samira G Ferreira
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; FMUC, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Bárbara S Pinheiro
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Cristina Lemos
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal
| | | | - Reinaldo N Takahashi
- Laboratory of Psychopharmacology, Dept. Pharmacology, Universidade Federal de Santa Catarina, Florianopolis 88049-900, Brazil
| | - Fernando J Sialana
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria; CeMM Research Center for Molecular Medicine of the Austrian Academy of Science, Lazarettgasse 14, AKH BT 25.3, A-1090 Vienna, Austria
| | - Gert Lubec
- Department of Pediatrics, Medical University of Vienna, Währinger Gürtel 18, A-1090 Vienna, Austria
| | - Rodrigo A Cunha
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; FMUC, Faculty of Medicine, University of Coimbra, 3004-504 Coimbra, Portugal
| | - Tibor Harkany
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-17177 Stockholm, Sweden; Department of Molecular Neurosciences, Center for Brain Research, Medical University of Vienna, A-1090 Vienna, Austria
| | - Attila Köfalvi
- CNC, Center for Neuroscience and Cell Biology of Coimbra, University of Coimbra, 3004-504 Coimbra, Portugal; Institute for Interdisciplinary Research, University of Coimbra, 3030-789 Coimbra, Portugal.
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Li C, Lu Q, Huang P, Fu T, Li C, Guo L, Xu X. Activity-dependent downregulation of M-Type (Kv7) K⁺ channels surface expression requires the activation of iGluRs/Ca²⁺/PKC signaling pathway in hippocampal neuron. Neuropharmacology 2015; 95:154-67. [PMID: 25796298 DOI: 10.1016/j.neuropharm.2015.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2014] [Revised: 02/26/2015] [Accepted: 03/09/2015] [Indexed: 10/23/2022]
Abstract
M-type (Kv7) K(+) channels, encoded by KCNQ2-KCNQ5 genes, play a pivotal role in controlling neuronal excitability. However, precisely how neuronal activity regulates Kv7 channel translocation has not yet been fully defined. Here we reported activity-dependent changes in Kv7 channel subunits Kv7.2 and Kv7.3 surface expression by glutamate (glu). In the present study, we found that treatment with glutamate rapidly caused a specific decrease in M-current as well as Kv7 channel surface expression in primary cultured hippocampal neurons. The glutamate effects were mimicked by NMDA and AMPA. The glutamate effects on Kv7 channels were partially attenuated by pre-treatment of NMDA receptors antagonist d,l-APV or AMPA-KA receptors antagonist CNQX. The signal required Ca(2+) influx through L-type Ca(2+) channel and intracellular Ca(2+) elevations. PKC activation was involved in the glutamate-induced reduction of Kv7 channel surface expression. Moreover, a significant reduction of Kv7 channel surface expression occurred following glycine-induced "chem"-LTP in vitro and hippocampus-dependent behavioral learning training in vivo. These results demonstrated that activity-dependent reduction of Kv7 channel surface expression through activation of ionotropic glutamate receptors (iGluRs)/Ca(2+)/PKC signaling pathway might be an important molecular mechanism for regulation of neuronal excitability and synaptic plasticity.
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Affiliation(s)
- Cai Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Qing Lu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Pengcheng Huang
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Tianli Fu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Changjun Li
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Lianjun Guo
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xulin Xu
- Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; The Key Laboratory for Drug Target Researches and Pharmacodynamic Evaluation of Hubei Province, Wuhan 430030, China; The Institute of Brain Research, Huazhong University of Science and Technology, Wuhan 430030, China.
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Guglielmi L, Servettini I, Caramia M, Catacuzzeno L, Franciolini F, D'Adamo MC, Pessia M. Update on the implication of potassium channels in autism: K(+) channelautism spectrum disorder. Front Cell Neurosci 2015; 9:34. [PMID: 25784856 PMCID: PMC4345917 DOI: 10.3389/fncel.2015.00034] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Accepted: 01/20/2015] [Indexed: 11/16/2022] Open
Abstract
Autism spectrum disorders (ASDs) are characterized by impaired ability to properly implement environmental stimuli that are essential to achieve a state of social and cultural exchange. Indeed, the main features of ASD are impairments of interpersonal relationships, verbal and non-verbal communication and restricted and repetitive behaviors. These aspects are often accompanied by several comorbidities such as motor delay, praxis impairment, gait abnormalities, insomnia, and above all epilepsy. Genetic analyses of autistic individuals uncovered deleterious mutations in several K+ channel types strengthening the notion that their intrinsic dysfunction may play a central etiologic role in ASD. However, indirect implication of K+ channels in ASD has been also reported. For instance, loss of fragile X mental retardation protein (FMRP) results in K+ channels deregulation, network dysfunction and ASD-like cognitive and behavioral symptoms. This review provides an update on direct and indirect implications of K+ channels in ASDs. Owing to a mounting body of evidence associating a channelopathy pathogenesis to autism and showing that nearly 500 ion channel proteins are encoded by the human genome, we propose to classify ASDs - whose susceptibility is significantly enhanced by ion channels defects, either in a monogenic or multigenic condition - in a new category named “channelAutismSpectrumDisorder” (channelASD; cASD) and introduce a new taxonomy (e.g., Kvx.y-channelASD and likewise Navx.y-channelASD, Cavx.y-channelASD; etc.). This review also highlights some degree of clinical and genetic overlap between K+ channelASDs and K+ channelepsies, whereby such correlation suggests that a subcategory characterized by a channelASD-channelepsy phenotype may be distinguished. Ultimately, this overview aims to further understand the different clinical subgroups and help parse out the distinct biological basis of autism that are essential to establish patient-tailored treatments.
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Affiliation(s)
- Luca Guglielmi
- Section of Physiology and Biochemistry, Department of Experimental Medicine, University of Perugia School of Medicine, Perugia Italy
| | - Ilenio Servettini
- Section of Physiology and Biochemistry, Department of Experimental Medicine, University of Perugia School of Medicine, Perugia Italy
| | - Martino Caramia
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia Italy
| | - Luigi Catacuzzeno
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia Italy
| | - Fabio Franciolini
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Perugia Italy
| | - Maria Cristina D'Adamo
- Section of Physiology and Biochemistry, Department of Experimental Medicine, University of Perugia School of Medicine, Perugia Italy
| | - Mauro Pessia
- Section of Physiology and Biochemistry, Department of Experimental Medicine, University of Perugia School of Medicine, Perugia Italy
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Potassium 2-(1-hydroxypentyl)-benzoate promotes long-term potentiation in Aβ1-42-injected rats and APP/PS1 transgenic mice. Acta Pharmacol Sin 2014; 35:869-78. [PMID: 24858312 DOI: 10.1038/aps.2014.29] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2013] [Accepted: 03/12/2014] [Indexed: 01/13/2023] Open
Abstract
AIM Potassium 2-(1-hydroxypentyl)-benzoate (dl-PHPB) is a new drug candidate for ischemic stroke. The aim of this study was to investigate the effects of dl-PHPB on memory deficits and long-term potentiation (LTP) impairment in animal models of Alzheimer's disease. METHODS The expression of NMDA receptor subunits GluN1 and GluN2B in the hippocampus and cortex of APP/PS1 transgenic mice were detected using Western blot analysis. Memory deficits of the mice were evaluated with the passive avoidance test. LTP impairment was studied in the dentate region of Aβ1-42-injected rats and APP/PS1 transgenic mice. RESULTS APP/PS1 transgenic mice showed significantly lower levels of GluN1 and p-GluN2B in hippocampus, and chronic administration of dl-PHPB (100 mg · kg(-1) · d(-1), po) reversed the downregulation of p-GluN2B, but did not change GluN1 level in the hippocampus. Furthermore, chronic administration of dl-PHPB reversed the memory deficits in APP/PS1 transgenic mice. In the dentate region of normal rats, injection of dl-PHPB (100 μmol/L, icv) did not change the basal synaptic transmission, but significantly enhanced the high-frequency stimulation (HFS)-induced LTP, which was completely prevented by pre-injection of APV (150 μmol/L, icv). Chronic administration of dl-PHPB (100 mg · kg(-1) · d(-1), po) reversed LTP impairment in Aβ1-42-injected normal rats and APP/PS1 transgenic mice. CONCLUSION Chronic administration of dl-PHPB improves learning and memory and promotes LTP in the animal models of Alzheimer's disease, possibly via increasing p-GluN2B expression in the hippocampus.
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Kv4 channels underlie A-currents with highly variable inactivation time courses but homogeneous other gating properties in the nucleus tractus solitarii. Pflugers Arch 2014; 467:789-803. [PMID: 24872163 DOI: 10.1007/s00424-014-1533-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 04/18/2014] [Accepted: 05/08/2014] [Indexed: 10/25/2022]
Abstract
In the nucleus of the tractus solitarii (NTS), a large proportion of neurones express transient A-type potassium currents (I KA) having deep influence on the fidelity of the synaptic transmission of the visceral primary afferent inputs to second-order neurones. Up to now, the strong impact of I KA within the NTS was considered to result exclusively from its variation in amplitude, and its molecular correlate(s) remained unknown. In order to identify which Kv channels underlie I KA in NTS neurones, the gating properties and the pharmacology of this current were determined using whole cell patch clamp recordings in slices. Complementary information was brought by immunohistochemistry. Strikingly, two neurone subpopulations characterized by fast or slow inactivation time courses (respectively about 50 and 200 ms) were discriminated. Both characteristics matched those of the Kv4 channel subfamily. The other gating properties, also matching the Kv4 channel ones, were homogeneous through the NTS. The activation and inactivation occurred at membrane potentials around the threshold for generating action potentials, and the time course of recovery from inactivation was rapid. Pharmacologically, I KA in NTS neurones was found to be resistant to tetraethylammonium (TEA), sea anemone toxin blood-depressing substance (BDS) and dendrotoxin (DTX), whereas Androctonus mauretanicus mauretanicus toxin 3 (AmmTX3), a scorpion toxin of the α-KTX 15 family that has been shown to block all the members of the Kv4 family, inhibited 80 % of I KA irrespectively of its inactivation time course. Finally, immunohistochemistry data suggested that, among the Kv4 channel subfamily, Kv4.3 is the prevalent subunit expressed in the NTS.
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Loss of functional A-type potassium channels in the dendrites of CA1 pyramidal neurons from a mouse model of fragile X syndrome. J Neurosci 2014; 33:19442-50. [PMID: 24336711 DOI: 10.1523/jneurosci.3256-13.2013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Despite the critical importance of voltage-gated ion channels in neurons, very little is known about their functional properties in Fragile X syndrome: the most common form of inherited cognitive impairment. Using three complementary approaches, we investigated the physiological role of A-type K(+) currents (I(KA)) in hippocampal CA1 pyramidal neurons from fmr1-/y mice. Direct measurement of I(KA) using cell-attached patch-clamp recordings revealed that there was significantly less I(KA) in the dendrites of CA1 neurons from fmr1-/y mice. Interestingly, the midpoint of activation for A-type K(+) channels was hyperpolarized for fmr1-/y neurons compared with wild-type, which might partially compensate for the lower current density. Because of the rapid time course for recovery from steady-state inactivation, the dendritic A-type K(+) current in CA1 neurons from both wild-type and fmr1-/y mice is likely mediated by K(V)4 containing channels. The net effect of the differences in I(KA) was that back-propagating action potentials had larger amplitudes producing greater calcium influx in the distal dendrites of fmr1-/y neurons. Furthermore, CA1 pyramidal neurons from fmr1-/y mice had a lower threshold for LTP induction. These data suggest that loss of I(KA) in hippocampal neurons may contribute to dendritic pathophysiology in Fragile X syndrome.
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Interactions of KChIP4a and its mutants with Ca2+ or Kv4.3 N-terminus by affinity capillary electrophoresis. Anal Biochem 2014; 449:99-105. [DOI: 10.1016/j.ab.2013.12.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 12/05/2013] [Accepted: 12/12/2013] [Indexed: 11/21/2022]
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Sosanya NM, Huang PPC, Cacheaux LP, Chen CJ, Nguyen K, Perrone-Bizzozero NI, Raab-Graham KF. Degradation of high affinity HuD targets releases Kv1.1 mRNA from miR-129 repression by mTORC1. ACTA ACUST UNITED AC 2013; 202:53-69. [PMID: 23836929 PMCID: PMC3704988 DOI: 10.1083/jcb.201212089] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Little is known about how a neuron undergoes site-specific changes in intrinsic excitability during neuronal activity. We provide evidence for a novel mechanism for mTORC1 kinase-dependent translational regulation of the voltage-gated potassium channel Kv1.1 messenger RNA (mRNA). We identified a microRNA, miR-129, that repressed Kv1.1 mRNA translation when mTORC1 was active. When mTORC1 was inactive, we found that the RNA-binding protein, HuD, bound to Kv1.1 mRNA and promoted its translation. Unexpectedly, inhibition of mTORC1 activity did not alter levels of miR-129 and HuD to favor binding to Kv1.1 mRNA. However, reduced mTORC1 signaling caused the degradation of high affinity HuD target mRNAs, freeing HuD to bind Kv1.1 mRNA. Hence, mTORC1 activity regulation of mRNA stability and high affinity HuD-target mRNA degradation mediates the bidirectional expression of dendritic Kv1.1 ion channels.
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Affiliation(s)
- Natasha M Sosanya
- Center for Learning and Memory, Section of Neurobiology, University of Texas at Austin, Austin, TX 78712, USA
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Gomes GM, Dalmolin GD, Cordeiro MDN, Gomez MV, Ferreira J, Rubin MA. The selective A-type K+ current blocker Tx3-1 isolated from the Phoneutria nigriventer venom enhances memory of naïve and Aβ(25-35)-treated mice. Toxicon 2013; 76:23-7. [PMID: 23994427 DOI: 10.1016/j.toxicon.2013.08.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/07/2013] [Accepted: 08/13/2013] [Indexed: 11/15/2022]
Abstract
Potassium channels regulate many neuronal functions, including neuronal excitability and synaptic plasticity, contributing, by these means, to mnemonic processes. In particular, A-type K(+) currents (IA) play a key role in hippocampal synaptic plasticity. Therefore, we evaluated the effect of the peptidic toxin Tx3-1, a selective blocker of IA currents, extracted from the venom of the spider Phoneutria nigriventer, on memory of mice. Administration of Tx3-1 (i.c.v., 300 pmol/site) enhanced both short- and long-term memory consolidation of mice tested in the novel object recognition task. In comparison, 4-aminopyridine (4-AP; i.c.v., 30-300 pmol/site), a non-selective K(+) channel blocker did not alter long-term memory and caused toxic side effects such as circling, freezing and tonic-clonic seizures. Moreover, Tx3-1 (i.c.v., 10-100 pmol/site) restored memory of Aβ25-35-injected mice, and exhibited a higher potency to improve memory of Aβ25-35-injected mice when compared to control group. These results show the effect of the selective blocker of IA currents Tx3-1 in both short- and long-term memory retention and in memory impairment caused by Aβ25-35, reinforcing the role of IA in physiological and pathological memory processes.
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Affiliation(s)
- Guilherme M Gomes
- Graduation Program in Biological Sciences, Toxicological Biochemistry, Building 18, Room 2203, Center of Exact and Natural Sciences, Federal University of Santa Maria, Santa Maria, RS 97105-900, Brazil
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Li Q, Fleming RL, Acheson SK, Madison RD, Moore SD, Risher ML, Wilson WA, Swartzwelder HS. Long-term modulation of A-type K(+) conductances in hippocampal CA1 interneurons in rats after chronic intermittent ethanol exposure during adolescence or adulthood. Alcohol Clin Exp Res 2013; 37:2074-85. [PMID: 23889304 DOI: 10.1111/acer.12204] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 04/29/2013] [Indexed: 12/14/2022]
Abstract
BACKGROUND Chronic alcohol use, especially exposure to alcohol during adolescence or young adulthood, is closely associated with cognitive deficits that may persist into adulthood. Therefore, it is essential to identify possible neuronal mechanisms underlying the observed deficits in learning and memory. Hippocampal interneurons play a pivotal role in regulating hippocampus-dependent learning and memory by exerting strong inhibition on excitatory pyramidal cells. The function of these interneurons is regulated not only by synaptic inputs from other types of neurons but is also precisely governed by their own intrinsic membrane ionic conductances. The voltage-gated A-type potassium current (IA ) regulates the intrinsic membrane properties of neurons, and disruption of IA is responsible for many neuropathological processes including learning and memory deficits. Thus, it represents a previously unexplored cellular mechanism whereby chronic ethanol (EtOH) may alter hippocampal memory-related functioning. METHODS Using whole-cell electrophysiological recording methods, we investigated the enduring effects of chronic intermittent ethanol (CIE) exposure during adolescence or adulthood on IA in rat CA1 interneurons. RESULTS We found that the mean peak amplitude of IA was significantly reduced after CIE in either adolescence or adulthood, but IA density was attenuated after CIE in adolescence but not after CIE in adulthood. In addition, the voltage-dependent steady-state activation and inactivation of IA were altered in interneurons after CIE. CONCLUSIONS These findings suggest that CIE can cause long-term changes in IA channels in interneurons and thus may alter their inhibitory influences on memory-related local hippocampal circuits, which could be, in turn, responsible for learning and memory impairments observed after chronic EtOH exposure.
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Affiliation(s)
- Qiang Li
- Durham VA Medical Center , Duke University Medical Center, Durham, North Carolina; Department of Psychiatry , Duke University Medical Center, Durham, North Carolina; Department of Neurosugery , Duke University Medical Center, Durham, North Carolina
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Regaya I, Aidi-Knani S, By Y, Condo J, Gerolami V, Berge-Lefranc JL, Ben Hamida J, Sabatier JM, Fenouillet E, Guieu R, Ruf J. SKCa Channels Blockage Increases the Expression of Adenosine A2A Receptor in Jurkat Human T Cells. Biores Open Access 2013; 2:163-8. [PMID: 23593569 PMCID: PMC3620471 DOI: 10.1089/biores.2012.0282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Adenosine is a nucleoside displaying various biological effects via stimulation of four G-protein-coupled receptors, A1, A2A, A2B, and A3. Adenosine also modulates voltage-gated (Kv) and small conductance calcium-activated (SKCa) potassium channels. The effect of these potassium channels on the expression of adenosine receptors is poorly understood. We evaluated the action of BgK (a natural Kv channel blocker) and Lei-Dab7 (a synthetic SKCa channel blocker) on the expression of adenosine A2A receptors (A2AR) in Jurkat human T cells. We found that Lei-Dab7, but not BgK, increased the maximal binding value of the tritiated ligand ZM241385 to A2AR in a dose-dependent manner (+45% at 5 nM; +70% at 50 nM as compared to control). These results were further confirmed by Western blotting using a specific monoclonal antibody to human A2AR. The ligand affinity-related dissociation constant and A2AR mRNA amount were not significantly modified by either drug. We suggest that modulation of SKCa channels can influence membrane expression of A2AR and thus has a therapeutic potential.
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Affiliation(s)
- Imed Regaya
- Unit of Functional Proteomics and Organic Food Preservation, Higher Institute of Applied Biological Sciences of Tunis, University of Tunis El Manar , Tunis, Tunisia . ; Higher Institute of Environmental Sciences and Technologies, University of Carthage , Carthage, Tunisia
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Social networking among voltage-activated potassium channels. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 117:269-302. [PMID: 23663972 DOI: 10.1016/b978-0-12-386931-9.00010-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Voltage-activated potassium channels (Kv channels) are ubiquitously expressed proteins that subserve a wide range of cellular functions. From their birth in the endoplasmic reticulum, Kv channels assemble from multiple subunits in complex ways that determine where they live in the cell, their biophysical characteristics, and their role in enabling different kinds of cells to respond to specific environmental signals to generate appropriate functional responses. This chapter describes the types of protein-protein interactions among pore-forming channel subunits and their auxiliary protein partners, as well as posttranslational protein modifications that occur in various cell types. This complex oligomerization of channel subunits establishes precise cell type-specific Kv channel localization and function, which in turn drives a diverse range of cellular signal transduction mechanisms uniquely suited to the physiological contexts in which they are found.
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Polman JAE, Welten JE, Bosch DS, de Jonge RT, Balog J, van der Maarel SM, de Kloet ER, Datson NA. A genome-wide signature of glucocorticoid receptor binding in neuronal PC12 cells. BMC Neurosci 2012; 13:118. [PMID: 23031785 PMCID: PMC3519639 DOI: 10.1186/1471-2202-13-118] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 09/24/2012] [Indexed: 12/22/2022] Open
Abstract
Background Glucocorticoids, secreted by the adrenals in response to stress, profoundly affect structure and plasticity of neurons. Glucocorticoid action in neurons is mediated by glucocorticoid receptors (GR) that operate as transcription factors in the regulation of gene expression and either bind directly to genomic glucocorticoid response elements (GREs) or indirectly to the genome via interactions with bound transcription factors. These two modes of action, respectively called transactivation and transrepression, result in the regulation of a wide variety of genes important for neuronal function. The objective of the present study was to identify genome-wide glucocorticoid receptor binding sites in neuronal PC12 cells using Chromatin ImmunoPrecipitation combined with next generation sequencing (ChIP-Seq). Results In total we identified 1183 genomic binding sites of GR, the majority of which were novel and not identified in other ChIP-Seq studies on GR binding. More than half (58%) of the binding sites contained a GRE. The remaining 42% of the GBS did not harbour a GRE and therefore likely bind GR via an intermediate transcription factor tethering GR to the DNA. While the GRE-containing binding sites were more often located nearby genes involved in general cell functions and processes such as apoptosis, cell motion, protein dimerization activity and vasculature development, the binding sites without a GRE were located nearby genes with a clear role in neuronal processes such as neuron projection morphogenesis, neuron projection regeneration, synaptic transmission and catecholamine biosynthetic process. A closer look at the sequence of the GR binding sites revealed the presence of several motifs for transcription factors that are highly divergent from those previously linked to GR-signaling, including Gabpa, Prrx2, Zfp281, Gata1 and Zbtb3. These transcription factors may represent novel crosstalk partners of GR in a neuronal context. Conclusions Here we present the first genome-wide inventory of GR-binding sites in a neuronal context. These results provide an exciting first global view into neuronal GR targets and the neuron-specific modes of GR action and potentially contributes to our understanding of glucocorticoid action in the brain.
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Affiliation(s)
- J Annelies E Polman
- Division of Medical Pharmacology, Leiden/Amsterdam Center for Drug Research, Leiden University Medical Center, Leiden, 2333 CC, The Netherlands
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Lee HY, Jan LY. Fragile X syndrome: mechanistic insights and therapeutic avenues regarding the role of potassium channels. Curr Opin Neurobiol 2012; 22:887-94. [PMID: 22483378 PMCID: PMC3393774 DOI: 10.1016/j.conb.2012.03.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 03/15/2012] [Indexed: 12/31/2022]
Abstract
Fragile X syndrome (FXS) is a common form of mental disability and one of the known causes of autism. The mutation responsible for FXS is a large expansion of the trinucleotide CGG repeats that leads to DNA methylation of the fragile X mental retardation gene 1 (FMR1) and transcriptional silencing, resulting in the absence of fragile X mental retardation protein (FMRP), an mRNA binding protein. Although it is widely known that FMRP is critical for metabotropic glutamate receptor (mGluR)-dependent long-term depression (LTD), which has provided a general theme for developing pharmacological drugs for FXS, specific downstream targets of FMRP may also be of therapeutic value. Since alterations in potassium channel expression level or activity could underlie neuronal network defects in FXS, here we describe recent findings on how these channels might be altered in mouse models of FXS and the possible therapeutic avenues for treating FXS.
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Affiliation(s)
- Hye Young Lee
- Howard Hughes Medical Institute, Departments of Physiology, Biochemistry and Biophysics, University of California, San Francisco, CA 94158, USA
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An L, Liu S, Yang Z, Zhang T. Cognitive impairment in rats induced by nano-CuO and its possible mechanisms. Toxicol Lett 2012; 213:220-7. [PMID: 22820425 DOI: 10.1016/j.toxlet.2012.07.007] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 06/11/2012] [Accepted: 07/10/2012] [Indexed: 11/18/2022]
Affiliation(s)
- Lei An
- College of Life Sciences, Nankai University, Tianjin 300071, PR China
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Truchet B, Manrique C, Sreng L, Chaillan FA, Roman FS, Mourre C. Kv4 potassium channels modulate hippocampal EPSP-spike potentiation and spatial memory in rats. Learn Mem 2012; 19:282-93. [PMID: 22700470 DOI: 10.1101/lm.025411.111] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Kv4 channels regulate the backpropagation of action potentials (b-AP) and have been implicated in the modulation of long-term potentiation (LTP). Here we showed that blockade of Kv4 channels by the scorpion toxin AmmTX3 impaired reference memory in a radial maze task. In vivo, AmmTX3 intracerebroventricular (i.c.v.) infusion increased and stabilized the EPSP-spike (E-S) component of LTP in the dentate gyrus (DG), with no effect on basal transmission or short-term plasticity. This increase in E-S potentiation duration could result from the combination of an increase in excitability of DG granular cells with a reduction of GABAergic inhibition, leading to a strong reduction of input specificity. Radioactive in situ hybridization (ISH) was used to evaluate the amounts of Kv4.2 and Kv4.3 mRNA in brain structures at different stages of a spatial learning task in naive, pseudoconditioned, and conditioned rats. Significant differences in Kv4.2 and Kv4.3 mRNA levels were observed between conditioned and pseudoconditioned rats. Kv4.2 and Kv4.3 mRNA levels were transiently up-regulated in the striatum, nucleus accumbens, retrosplenial, and cingulate cortices during early stages of learning, suggesting an involvement in the switch from egocentric to allocentric strategies. Spatial learning performance was positively correlated with the levels of Kv4.2 and Kv4.3 mRNAs in several of these brain structures. Altogether our findings suggest that Kv4 channels could increase the signal-to-noise ratio during information acquisition, thereby allowing a better encoding of the memory trace.
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Affiliation(s)
- Bruno Truchet
- Laboratory of Neuroscience and Cognition-LNC-UMR 7291, Centre National de la Recherche Scientifique-Aix-Marseille Université, Centre Saint-Charles, 13331 Marseille, France
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Towards therapeutic applications of arthropod venom k(+)-channel blockers in CNS neurologic diseases involving memory acquisition and storage. J Toxicol 2012; 2012:756358. [PMID: 22701481 PMCID: PMC3373146 DOI: 10.1155/2012/756358] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Accepted: 02/08/2012] [Indexed: 12/31/2022] Open
Abstract
Potassium channels are the most heterogeneous and widely distributed group of ion channels and play important functions in all cells, in both normal and pathological mechanisms, including learning and memory processes. Being fundamental for many diverse physiological processes, K+-channels are recognized as potential therapeutic targets in the treatment of several Central Nervous System (CNS) diseases, such as multiple sclerosis, Parkinson's and Alzheimer's diseases, schizophrenia, HIV-1-associated dementia, and epilepsy. Blockers of these channels are therefore potential candidates for the symptomatic treatment of these neuropathies, through their neurological effects. Venomous animals have evolved a wide set of toxins for prey capture and defense. These compounds, mainly peptides, act on various pharmacological targets, making them an innumerable source of ligands for answering experimental paradigms, as well as for therapeutic application. This paper provides an overview of CNS K+-channels involved in memory acquisition and storage and aims at evaluating the use of highly selective K+-channel blockers derived from arthropod venoms as potential therapeutic agents for CNS diseases involving learning and memory mechanisms.
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Lee HY, Ge WP, Huang W, He Y, Wang GX, Rowson-Baldwin A, Smith SJ, Jan YN, Jan LY. Bidirectional regulation of dendritic voltage-gated potassium channels by the fragile X mental retardation protein. Neuron 2012; 72:630-42. [PMID: 22099464 DOI: 10.1016/j.neuron.2011.09.033] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2011] [Indexed: 02/01/2023]
Abstract
How transmitter receptors modulate neuronal signaling by regulating voltage-gated ion channel expression remains an open question. Here we report dendritic localization of mRNA of Kv4.2 voltage-gated potassium channel, which regulates synaptic plasticity, and its local translational regulation by fragile X mental retardation protein (FMRP) linked to fragile X syndrome (FXS), the most common heritable mental retardation. FMRP suppression of Kv4.2 is revealed by elevation of Kv4.2 in neurons from fmr1 knockout (KO) mice and in neurons expressing Kv4.2-3'UTR that binds FMRP. Moreover, treating hippocampal slices from fmr1 KO mice with Kv4 channel blocker restores long-term potentiation induced by moderate stimuli. Surprisingly, recovery of Kv4.2 after N-methyl-D-aspartate receptor (NMDAR)-induced degradation also requires FMRP, likely due to NMDAR-induced FMRP dephosphorylation, which turns off FMRP suppression of Kv4.2. Our study of FMRP regulation of Kv4.2 deepens our knowledge of NMDAR signaling and reveals a FMRP target of potential relevance to FXS.
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Affiliation(s)
- Hye Young Lee
- Howard Hughes Medical Institute Departments of Physiology, Biochemistry, and Biophysics, University of California, San Francisco, CA 94158, USA
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Aβ inhibition of ionic conductance in mouse basal forebrain neurons is dependent upon the cellular prion protein PrPC. J Neurosci 2012; 31:16292-7. [PMID: 22072680 DOI: 10.1523/jneurosci.4367-11.2011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Current therapies for Alzheimer's disease (AD) address a loss of cholinergic neurons, while accumulation of neurotoxic amyloid β (Aβ) peptide assemblies is thought central to molecular pathogenesis. Overlaps may exist between prionopathies and AD wherein Aβ oligomers bind to the cellular prion protein PrP(C) and inhibit synaptic plasticity in the hippocampus (Laurén et al., 2009). Here we applied oligomeric Aβ to neurons with different PrP (Prnp) gene dosage. Whole-cell recordings were obtained from dissociated neurons of the diagonal band of Broca (DBB), a cholinergic basal forebrain nucleus. In wild-type (wt) mice, Aβ₁₋₄₂ evoked a concentration-dependent reduction of whole-cell outward currents in a voltage range between -30 and +30 mV; reduction occurred through a combined modulation of a suite of potassium conductances including the delayed rectifier (I(K)), the transient outward (I(A)), and the iberiotoxin-sensitive (calcium-activated potassium, I(C)) currents. Inhibition was not seen with Aβ₄₂₋₁ peptide, while Aβ₁₋₄₂-induced responses were reduced by application of anti-PrP antibody, attenuated in cells from Prnp⁰/⁺ hemizygotes, and absent in Prnp⁰/⁰ homozygotes. Similarly, amyloidogenic amylin peptide depressed DBB whole-cell currents in DBB cells from wt mice, but not Prnp⁰/⁰ homozygotes. While prior studies give broad support for a neuroprotective function for PrP(C), our data define a latent pro-pathogenic role in the presence of amyloid assemblies.
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Kerti K, Lorincz A, Nusser Z. Unique somato-dendritic distribution pattern of Kv4.2 channels on hippocampal CA1 pyramidal cells. Eur J Neurosci 2011; 35:66-75. [PMID: 22098631 PMCID: PMC3428895 DOI: 10.1111/j.1460-9568.2011.07907.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
A-type K+ current (IA) plays a critical role in controlling the excitability of pyramidal cell (PC) dendrites. In vitro dendritic patch-pipette recordings have demonstrated a prominent, sixfold increase in IA density along the main apical dendrites of rat hippocampal CA1 PCs. In these cells, IA is mediated by Kv4.2 subunits, whose precise subcellular distribution and densities in small-diameter oblique dendrites and dendritic spines are still unknown. Here we examined the densities of the Kv4.2 subunit in 13 axo-somato-dendritic compartments of CA1 PCs using a highly sensitive, high-resolution quantitative immunogold localization method (sodium dodecyl sulphate-digested freeze-fracture replica-labelling). Only an approximately 70% increase in Kv4.2 immunogold density was observed along the proximo-distal axis of main apical dendrites in the stratum radiatum with a slight decrease in density in stratum lacunosum-moleculare. A similar pattern was detected for all dendritic compartments, including main apical dendrites, small-diameter oblique dendrites and dendritic spines. The specificity of the somato-dendritic labelling was confirmed in Kv4.2−/− tissue. No specific immunolabelling for the Kv4.2 subunit was found in SNAP-25-containing presynaptic axons. Our results demonstrate a novel distribution pattern of a voltage-gated ion channel along the somato-dendritic surface of CA1 PCs, and suggest that the increase in the IA along the proximo-distal axis of PC dendrites cannot be solely explained by a corresponding increase in Kv4.2 channel number.
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Affiliation(s)
- Katalin Kerti
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
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Fontán-Lozano Á, Suárez-Pereira I, González-Forero D, Carrión ÁM. The A-current modulates learning via NMDA receptors containing the NR2B subunit. PLoS One 2011; 6:e24915. [PMID: 21966384 PMCID: PMC3180285 DOI: 10.1371/journal.pone.0024915] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Accepted: 08/19/2011] [Indexed: 11/20/2022] Open
Abstract
Synaptic plasticity involves short- and long-term events, although the molecular mechanisms that underlie these processes are not fully understood. The transient A-type K+ current (IA) controls the excitability of the dendrites from CA1 pyramidal neurons by regulating the back-propagation of action potentials and shaping synaptic input. Here, we have studied how decreases in IA affect cognitive processes and synaptic plasticity. Using wild-type mice treated with 4-AP, an IA inhibitor, and mice lacking the DREAM protein, a transcriptional repressor and modulator of the IA, we demonstrate that impairment of IA decreases the stimulation threshold for learning and the induction of early-LTP. Hippocampal electrical recordings in both models revealed alterations in basal electrical oscillatory properties toward low-theta frequencies. In addition, we demonstrated that the facilitated learning induced by decreased IA requires the activation of NMDA receptors containing the NR2B subunit. Together, these findings point to a balance between the IA and the activity of NR2B-containing NMDA receptors in the regulation of learning.
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Affiliation(s)
- Ángela Fontán-Lozano
- División de Neurociencias, Universidad Pablo de Olavide de Sevilla, Sevilla, Spain
- * E-mail: (AF-L); (AMC)
| | - Irene Suárez-Pereira
- División de Neurociencias, Universidad Pablo de Olavide de Sevilla, Sevilla, Spain
| | | | - Ángel Manuel Carrión
- División de Neurociencias, Universidad Pablo de Olavide de Sevilla, Sevilla, Spain
- * E-mail: (AF-L); (AMC)
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DPP6 establishes the A-type K(+) current gradient critical for the regulation of dendritic excitability in CA1 hippocampal neurons. Neuron 2011; 71:1102-15. [PMID: 21943606 DOI: 10.1016/j.neuron.2011.08.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2011] [Indexed: 11/21/2022]
Abstract
Subthreshold-activating A-type K(+) currents are essential for the proper functioning of the brain, where they act to delay excitation and regulate firing frequency. In CA1 hippocampal pyramidal neuron dendrites, the density of A-type K(+) current increases with distance from the soma, playing an important role in synaptic integration and plasticity. The mechanism underlying this gradient has, however, remained elusive. Here, dendritic recordings from mice lacking the Kv4 transmembrane auxiliary subunit DPP6 revealed that this protein is critical for generating the A-current gradient. Loss of DPP6 led to a decrease in A-type current, specifically in distal dendrites. Decreased current density was accompanied by a depolarizing shift in the voltage dependence of channel activation. Together these changes resulted in hyperexcitable dendrites with enhanced dendritic AP back-propagation, calcium electrogenesis, and induction of synaptic long-term potentiation. Despite enhanced dendritic excitability, firing behavior evoked by somatic current injection was mainly unaffected in DPP6-KO recordings, indicating compartmentalized regulation of neuronal excitability.
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An L, Li Z, Yang Z, Zhang T. Cognitive deficits induced by melamine in rats. Toxicol Lett 2011; 206:276-80. [PMID: 21888959 DOI: 10.1016/j.toxlet.2011.08.009] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2011] [Revised: 08/13/2011] [Accepted: 08/16/2011] [Indexed: 10/17/2022]
Abstract
Many studies reported that infants and animals were affected by food containing melamine, and the renal pathology was the main manifestation in intoxicated case. Our previous studies showed that melamine could impair hippocampal function and inhibited differentiated PC12 cell proliferation in vitro. The present study aimed to examine the effect on hippocampus and the possible mechanism induced by melamine in vivo. To address the hypothesis that melamine would impair the hippocampal function in vivo and then induce cognitive deficits, male Wistar rats were used to establish an animal model and melamine administered at a dose of 300 mgkg/day for 4 weeks. Morris water maze (MWM) test was employed to evaluate the learning and memory. The long term potentiation (LTP) from Schaffer collaterals to CA1 region in the hippocampus was recorded. The result of MWM test showed that there were significant deficits of learning and memory induced by melamine. LTP test presented that field excitatory postsynaptic potentials (fEPSPs) slopes were significantly lower in melamine group compared to that in control group. In conclusion, melamine had a toxic influence on hippocampus, which induced the learning and memory deficits. It suggested that the potential mechanism was associated with impairments of synaptic plasticity.
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Affiliation(s)
- Lei An
- College of Life Sciences and Key Lab of Bioactive Materials, Ministry of Education, Tianjin, 300071, PR China
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Jo A, Kim HK. Up-regulation of dendritic Kv4.2 mRNA by activation of the NMDA receptor. Neurosci Lett 2011; 496:129-34. [PMID: 21511008 DOI: 10.1016/j.neulet.2011.03.099] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 03/03/2011] [Accepted: 03/31/2011] [Indexed: 11/25/2022]
Abstract
The localization of Kv4.2 mRNAs in dendritic regions suggests that Kv4.2 channels, which originate from on-site protein synthesis in the dendrites, might play a role in synaptic function. In this study, we determined the molecular mechanisms of dendritic transport of Kv4.2 mRNA. Three hours of incubation following a brief depolarization resulted in significant increases in Kv4.2 mRNA levels in both cell bodies and dendrites. The increase in the mRNA in the dendrites was mediated by transcription- and translation-independent mechanisms. In order to further clarify the molecular mechanism of dendritic transport of Kv4.2 mRNA, we used the GFP-MS2 reporting system. Consistent with the in situ data, depolarization resulted in significant increases in dendritic levels of Kv4.2 mRNA at the maximal length at which Kv4.2 mRNA could be detected. These increases were mediated in a synaptic NMDA receptor- and Ca(2+)-dependent fashion. Collectively, these results indicate that Kv4.2 mRNA levels are regulated in response to synaptic activity, and this phenomenon may be the mechanism underlying the homeostasis of Kv4.2 protein on dendritic surfaces.
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Affiliation(s)
- Anna Jo
- Department of Medicine and Microbiology, College of Medicine, Signaling Disorder Research Center, Chungbuk National University, Cheongju 361-763, Republic of Korea
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Nestor MW, Hoffman DA. Differential cycling rates of Kv4.2 channels in proximal and distal dendrites of hippocampal CA1 pyramidal neurons. Hippocampus 2011; 22:969-80. [PMID: 21472817 DOI: 10.1002/hipo.20899] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/06/2010] [Indexed: 11/06/2022]
Abstract
The heterogeneous expression of voltage-gated channels in dendrites suggests that neurons perform local microdomain computations at different regions. It has been shown that A-type K(+) channels have a nonuniform distribution along the primary apical dendrite in CA1 pyramidal neurons, increasing with distance from the soma. Kv4.2 channels, which are responsible for the somatodendritic A-type K(+) current in CA1 pyramidal neurons, shape local synaptic input, and regulate the back-propagation of APs into dendrites. Experiments were performed to test the hypothesis that Kv4.2 channels are differentially trafficked at different regions along the apical dendrite during basal activity and upon stimulation in CA1 neurons. Proximal (50-150 μm from the soma, primary and oblique) and distal (>200 μm) apical dendrites were selected. The fluorescence recovery after photobleaching (FRAP) technique was used to measure basal cycling rates of EGFP-tagged Kv4.2 (Kv4.2g). We found that the cycling rate of Kv4.2 channels was one order of magnitude slower at both primary and oblique dendrites between 50 and 150 μm from the soma. Kv4.2 channel cycling increased significantly at 200 to 250 μm from the soma. Expression of a Kv4.2 mutant lacking a phosphorylation site for protein kinase-A (Kv4.2gS552A) abolished this distance-dependent change in channel cycling; demonstrating that phosphorylation by PKA underlies the increased mobility in distal dendrites. Neuronal stimulation by α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) treatment increased cycling of Kv4.2 channels significantly at distal sites only. This activity-dependent increase in Kv4.2 cycling at distal dendrites was blocked by expression of Kv4.2gS552A. These results indicate that distance-dependent Kv4.2 mobility is regulated by activity-dependent phosphorylation of Kv4.2 by PKA.
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Affiliation(s)
- Michael W Nestor
- Molecular Neurophysiology and Biophysics Unit, Laboratory of Cellular and Synaptic Neurophysiology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892-3715, USA.
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AKAP79/150 impacts intrinsic excitability of hippocampal neurons through phospho-regulation of A-type K+ channel trafficking. J Neurosci 2011; 31:1323-32. [PMID: 21273417 DOI: 10.1523/jneurosci.5383-10.2011] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Kv4.2, as the primary α-subunit of rapidly inactivating, A-type voltage-gated K(+) (Kv) channels expressed in hippocampal CA1 pyramidal dendrites, plays a critical role in regulating their excitability. Activity-dependent trafficking of Kv4.2 relies on C-terminal protein kinase A (PKA) phosphorylation. A-kinase-anchoring proteins (AKAPs) target PKA to glutamate receptor and ion channel complexes to allow for discrete, local signaling. As part of a previous study, we showed that AKAP79/150 interacts with Kv4.2 complexes and that the two proteins colocalize in hippocampal neurons. However, the nature and functional consequence of their interaction has not been previously explored. Here, we report that the C-terminal domain of Kv4.2 interacts with an internal region of AKAP79/150 that overlaps with its MAGUK (membrane-associated guanylate kinase)-binding domain. We show that AKAP79/150-anchored PKA activity controls Kv4.2 surface expression in heterologous cells and hippocampal neurons. Consistent with these findings, disrupting PKA anchoring led to a decrease in neuronal excitability, while preventing dephosphorylation by the phosphatase calcineurin resulted in increased excitability. These results demonstrate that AKAP79/150 provides a platform for dynamic PKA regulation of Kv4.2 expression, fundamentally impacting CA1 excitability.
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