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Brown SP, Lawson RJ, Moreno JD, Ransdell JL. A Reinterpretation of the Relationship between Persistent and Resurgent Sodium Currents. J Neurosci 2024; 44:e2396232024. [PMID: 38858080 PMCID: PMC11255426 DOI: 10.1523/jneurosci.2396-23.2024] [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: 12/21/2023] [Revised: 05/14/2024] [Accepted: 05/31/2024] [Indexed: 06/12/2024] Open
Abstract
The resurgent sodium current (INaR) activates on membrane repolarization, such as during the downstroke of neuronal action potentials. Due to its unique activation properties, INaR is thought to drive high rates of repetitive neuronal firing. However, INaR is often studied in combination with the persistent or noninactivating portion of sodium currents (INaP). We used dynamic clamp to test how INaR and INaP individually affect repetitive firing in adult cerebellar Purkinje neurons from male and female mice. We learned INaR does not scale repetitive firing rates due to its rapid decay at subthreshold voltages and that subthreshold INaP is critical in regulating neuronal firing rate. Adjustments to the voltage-gated sodium conductance model used in these studies revealed INaP and INaR can be inversely scaled by adjusting occupancy in the slow-inactivated kinetic state. Together with additional dynamic clamp experiments, these data suggest the regulation of sodium channel slow inactivation can fine-tune INaP and Purkinje neuron repetitive firing rates.
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Affiliation(s)
- Samuel P Brown
- Department of Biology, Miami University, Oxford, Ohio 45056
| | - Ryan J Lawson
- Department of Biology, Miami University, Oxford, Ohio 45056
| | - Jonathan D Moreno
- Division of Cardiology, Department of Medicine, Washington University in St. Louis, St. Louis, Missouri 63130
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2
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Aman TK, Raman IM. Resurgent current in context: Insights from the structure and function of Na and K channels. Biophys J 2024; 123:1924-1941. [PMID: 38130058 DOI: 10.1016/j.bpj.2023.12.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Revised: 12/07/2023] [Accepted: 12/18/2023] [Indexed: 12/23/2023] Open
Abstract
Discovered just over 25 years ago in cerebellar Purkinje neurons, resurgent Na current was originally described operationally as a component of voltage-gated Na current that flows upon repolarization from relatively depolarized potentials and speeds recovery from inactivation, increasing excitability. Its presence in many excitable cells and absence from others has raised questions regarding its biophysical and molecular mechanisms. Early studies proposed that Na channels capable of generating resurgent current are subject to a rapid open-channel block by an endogenous blocking protein, which binds upon depolarization and unblocks upon repolarization. Since the time that this mechanism was suggested, many physiological and structural studies of both Na and K channels have revealed aspects of gating and conformational states that provide insights into resurgent current. These include descriptions of domain movements for activation and inactivation, solution of cryo-EM structures with pore-blocking compounds, and identification of native blocking domains, proteins, and modulatory subunits. Such results not only allow the open-channel block hypothesis to be refined but also link it more clearly to research that preceded it. This review considers possible mechanisms for resurgent Na current in the context of earlier and later studies of ion channels and suggests a framework for future research.
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Affiliation(s)
- Teresa K Aman
- Department of Neurobiology, Northwestern University, Evanston, Illinois
| | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, Illinois.
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3
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Brown SP, Lawson RJ, Moreno JD, Ransdell JL. A Reinterpretation of the Relationship Between Persistent and Resurgent Sodium Currents. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.25.564042. [PMID: 38187680 PMCID: PMC10769191 DOI: 10.1101/2023.10.25.564042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
The resurgent sodium current (INaR) activates on membrane repolarization, such as during the downstroke of neuronal action potentials. Due to its unique activation properties, INaR is thought to drive high rates of repetitive neuronal firing. However, INaR is often studied in combination with the persistent or non-inactivating portion of sodium currents (INaP). We used dynamic clamp to test how INaR and INaP individually affect repetitive firing in adult cerebellar Purkinje neurons from male and female mice. We learned INaR does not scale repetitive firing rates due to its rapid decay at subthreshold voltages, and that subthreshold INaP is critical in regulating neuronal firing rate. Adjustments to the Nav conductance model used in these studies revealed INaP and INaR can be inversely scaled by adjusting occupancy in the slow inactivated kinetic state. Together with additional dynamic clamp experiments, these data suggest the regulation of sodium channel slow inactivation can fine-tune INaP and Purkinje neuron repetitive firing rates.
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Affiliation(s)
| | - Ryan J. Lawson
- Department of Biology, Miami University, Oxford, OH 45056
| | - Jonathan D. Moreno
- Division of Cardiology, Department of Medicine, Washington University in St. Louis, St. Louis, MO 63130
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4
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Miyazaki H, Nishioka S, Yamanaka T, Abe M, Imamura Y, Miyasaka T, Kakuda N, Oohashi T, Shimogori T, Yamakawa K, Ikawa M, Nukina N. Generation and characterization of cerebellar granule neurons specific knockout mice of Golli-MBP. Transgenic Res 2024; 33:99-117. [PMID: 38684589 PMCID: PMC11176102 DOI: 10.1007/s11248-024-00382-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Accepted: 04/02/2024] [Indexed: 05/02/2024]
Abstract
Golli-myelin basic proteins, encoded by the myelin basic protein gene, are widely expressed in neurons and oligodendrocytes in the central nervous system. Further, prior research has shown that Golli-myelin basic protein is necessary for myelination and neuronal maturation during central nervous system development. In this study, we established Golli-myelin basic protein-floxed mice to elucidate the cell-type-specific effects of Golli-myelin basic protein knockout through the generation of conditional knockout mice (Golli-myelin basic proteinsfl/fl; E3CreN), in which Golli-myelin basic proteins were specifically deleted in cerebellar granule neurons, where Golli-myelin basic proteins are expressed abundantly in wild-type mice. To investigate the role of Golli-myelin basic proteins in cerebellar granule neurons, we further performed histopathological analyses of these mice, with results indicating no morphological changes or degeneration of the major cellular components of the cerebellum. Furthermore, behavioral analysis showed that Golli-myelin basic proteinsfl/fl; E3CreN mice were healthy and did not display any abnormal behavior. These results suggest that the loss of Golli-myelin basic proteins in cerebellar granule neurons does not lead to cerebellar perturbations or behavioral abnormalities. This mouse model could therefore be employed to analyze the effect of Golli-myelin basic protein deletion in specific cell types of the central nervous system, such as other neuronal cells and oligodendrocytes, or in lymphocytes of the immune system.
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Grants
- 16K07005 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 16H06276 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 17H01564 Grants-in-Aid from the Ministry of Education, Culture, Sports, Science, and Technology (MEXT) of Japan
- 20ek0109310h0003 AMED
- The Center for Baby Science, Doshisha University
- Takeda Science Foundation
- Ichiro Kanehara Foundation for the Promotion of Medical Sciences and Medical Care
- Okayama University
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Affiliation(s)
- Haruko Miyazaki
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan.
- Department of Molecular Biology and Biochemistry, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan.
| | - Saki Nishioka
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
- Department of Neuroscience of Disease, Brain Research Institute, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata, 951-8585, Japan
| | - Manabu Abe
- Department of Animal Model Development, Brain Research Institute, Niigata University, 1-757 Asahimachidori, Chuo-ku, Niigata, 951-8585, Japan
| | - Yukio Imamura
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Tomohiro Miyasaka
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Nobuto Kakuda
- Faculty of Life and Medical Sciences, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Toshitaka Oohashi
- Department of Molecular Biology and Biochemistry, Dentistry and Pharmaceutical Sciences, Okayama University Graduate School of Medicine, 2-5-1 Shikata-cho, Kita-ku, Okayama, 700-8558, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako-shi, Saitama, 351-0198, Japan
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Sciences, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Masahito Ikawa
- Department of Experimental Genome Research, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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Do QB, Noor H, Marquez-Gomez R, Cramb KML, Ng B, Abbey A, Ibarra-Aizpurua N, Caiazza MC, Sharifi P, Lang C, Beccano-Kelly D, Baleriola J, Bengoa-Vergniory N, Wade-Martins R. Early deficits in an in vitro striatal microcircuit model carrying the Parkinson's GBA-N370S mutation. NPJ Parkinsons Dis 2024; 10:82. [PMID: 38609392 PMCID: PMC11014935 DOI: 10.1038/s41531-024-00694-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Accepted: 03/26/2024] [Indexed: 04/14/2024] Open
Abstract
Understanding medium spiny neuron (MSN) physiology is essential to understand motor impairments in Parkinson's disease (PD) given the architecture of the basal ganglia. Here, we developed a custom three-chambered microfluidic platform and established a cortico-striato-nigral microcircuit partially recapitulating the striatal presynaptic landscape in vitro using induced pluripotent stem cell (iPSC)-derived neurons. We found that, cortical glutamatergic projections facilitated MSN synaptic activity, and dopaminergic transmission enhanced maturation of MSNs in vitro. Replacement of wild-type iPSC-derived dopamine neurons (iPSC-DaNs) in the striatal microcircuit with those carrying the PD-related GBA-N370S mutation led to a depolarisation of resting membrane potential and an increase in rheobase in iPSC-MSNs, as well as a reduction in both voltage-gated sodium and potassium currents. Such deficits were resolved in late microcircuit cultures, and could be reversed in younger cultures with antagonism of protein kinase A activity in iPSC-MSNs. Taken together, our results highlight the unique utility of modelling striatal neurons in a modular physiological circuit to reveal mechanistic insights into GBA1 mutations in PD.
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Affiliation(s)
- Quyen B Do
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Humaira Noor
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
- Nuffield Department of Medicine (NDM), University of Oxford, Henry Wellcome Building for Molecular Physiology, Old Road, Oxford, OX3 7BN, UK
| | - Ricardo Marquez-Gomez
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Kaitlyn M L Cramb
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Bryan Ng
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
| | - Ajantha Abbey
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
| | - Naroa Ibarra-Aizpurua
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
| | - Maria Claudia Caiazza
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Parnaz Sharifi
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
| | - Charmaine Lang
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA
| | - Dayne Beccano-Kelly
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK
| | - Jimena Baleriola
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Ikerbasque-Basque Foundation for Science, Bilbao, Spain
| | - Nora Bengoa-Vergniory
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK.
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA.
- Achucarro Basque Center for Neuroscience, Leioa, Spain.
- Ikerbasque-Basque Foundation for Science, Bilbao, Spain.
- University of the Basque Country (UPV/EHU), Department of Neuroscience, Leioa, Spain.
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre and Department of Physiology, Anatomy and Genetics, University of Oxford, South Park Road, Oxford, OX1 3QU, UK.
- Kavli Institute for Neuroscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Park Road, Oxford, OX1 3QU, UK.
- Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, 20815, USA.
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6
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Suzuki T, Hattori S, Mizukami H, Nakajima R, Hibi Y, Kato S, Matsuzaki M, Ikebe R, Miyakawa T, Yamakawa K. Inversed Effects of Nav1.2 Deficiency at Medial Prefrontal Cortex and Ventral Tegmental Area for Prepulse Inhibition in Acoustic Startle Response. Mol Neurobiol 2024; 61:622-634. [PMID: 37650965 DOI: 10.1007/s12035-023-03610-6] [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: 01/05/2023] [Accepted: 08/20/2023] [Indexed: 09/01/2023]
Abstract
Numerous pathogenic variants of SCN2A gene, encoding voltage-gated sodium channel α2 subunit Nav1.2 protein, have been identified in a wide spectrum of neuropsychiatric disorders including schizophrenia. However, pathological mechanisms for the schizophrenia-relevant behavioral abnormalities caused by the variants remain poorly understood. Here in this study, we characterized mouse lines with selective Scn2a deletion at schizophrenia-related brain regions, medial prefrontal cortex (mPFC) or ventral tegmental area (VTA), obtained by injecting adeno-associated viruses (AAV) expressing Cre recombinase into homozygous Scn2a-floxed (Scn2afl/fl) mice, in which expression of the Scn2a was locally deleted in the presence of Cre recombinase. The mice lacking Scn2a in the mPFC exhibited a tendency for a reduction in prepulse inhibition (PPI) in acoustic startle response. Conversely, the mice lacking Scn2a in the VTA showed a significant increase in PPI. We also found that the mice lacking Scn2a in the mPFC displayed increased sociability, decreased locomotor activity, and increased anxiety-like behavior, while the mice lacking Scn2a in the VTA did not show any other abnormalities in these parameters except for vertical activity which is one of locomotor activities. These results suggest that Scn2a-deficiencies in mPFC and VTA are inversely relevant for the schizophrenic phenotypes in patients with SCN2A variants.
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Affiliation(s)
- Toshimitsu Suzuki
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan.
| | - Satoko Hattori
- Division of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
- Research Creation Support Center, Aichi Medical University, Nagakute, Aichi, 480-1195, Japan
| | - Hiroaki Mizukami
- Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Tochigi, 329-0498, Japan
| | - Ryuichi Nakajima
- Division of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Yurina Hibi
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Saho Kato
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Mahoro Matsuzaki
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Ryu Ikebe
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
| | - Tsuyoshi Miyakawa
- Division of Systems Medical Science, Center for Medical Science, Fujita Health University, Toyoake, Aichi, 470-1192, Japan
| | - Kazuhiro Yamakawa
- Department of Neurodevelopmental Disorder Genetics, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, 467-8601, Japan
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7
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Raman IM. The Hodgkin-Huxley-Katz Prize Lecture: A Markov model with permeation-dependent gating that accounts for resurgent current of voltage-gated Na channels. J Physiol 2023; 601:5147-5164. [PMID: 37837315 PMCID: PMC10913027 DOI: 10.1113/jp285166] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Accepted: 09/20/2023] [Indexed: 10/16/2023] Open
Abstract
Many neurons that fire high-frequency action potentials express specialized voltage-gated Na channel complexes that not only conduct transient current upon depolarization, but also pass resurgent current upon repolarization. The resurgent current is associated with recovery of transient current, even at moderately negative potentials where fast inactivation is usually absorbing. The combined results of many experimental studies have led to the hypothesis that resurgent current flows upon repolarization when an endogenous blocking protein that occludes open channels at depolarized potentials is expelled by inwardly permeating Na ions. Additional observations have suggested that the position of the voltage sensor of domain IV regulates the affinity of the channel for the putative blocker. To test the effectiveness of a kinetic scheme incorporating these features, here we develop and justify a Markov model with states grounded in known Na channel conformations. Simulations were designed to investigate whether including a permeation-dependent unblocking rate constant and two open-blocked states, superimposed on conformations and voltage-sensitive movements present in all voltage-gated Na channels, is sufficient to account for the unusual gating of channels with a resurgent component. Optimizing rate constant parameters against a wide range of experimental data from cerebellar Purkinje cells demonstrates that a kinetic scheme for Na channels incorporating the novel aspects of a permeation-dependent unblock, as well as distinct high- and low-affinity blocked states, reproduces all the attributes of experimentally recorded Na currents in a physiologically plausible manner.
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Affiliation(s)
- Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL, USA
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8
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Schamiloglu S, Wu H, Zhou M, Kwan AC, Bender KJ. Dynamic Foraging Behavior Performance Is Not Affected by Scn2a Haploinsufficiency. eNeuro 2023; 10:ENEURO.0367-23.2023. [PMID: 38151324 PMCID: PMC10755640 DOI: 10.1523/eneuro.0367-23.2023] [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: 09/19/2023] [Revised: 10/23/2023] [Accepted: 11/14/2023] [Indexed: 12/29/2023] Open
Abstract
Dysfunction in the gene SCN2A, which encodes the voltage-gated sodium channel Nav1.2, is strongly associated with neurodevelopmental disorders including autism spectrum disorder and intellectual disability (ASD/ID). This dysfunction typically manifests in these disorders as a haploinsufficiency, where loss of one copy of a gene cannot be compensated for by the other allele. Scn2a haploinsufficiency affects a range of cells and circuits across the brain, including associative neocortical circuits that are important for cognitive flexibility and decision-making behaviors. Here, we tested whether Scn2a haploinsufficiency has any effect on a dynamic foraging task that engages such circuits. Scn2a +/- mice and wild-type (WT) littermates were trained on a choice behavior where the probability of reward between two options varied dynamically across trials and where the location of the high reward underwent uncued reversals. Despite impairments in Scn2a-related neuronal excitability, we found that both male and female Scn2a +/- mice performed these tasks as well as wild-type littermates, with no behavioral difference across genotypes in learning or performance parameters. Varying the number of trials between reversals or probabilities of receiving reward did not result in an observable behavioral difference, either. These data suggest that, despite heterozygous loss of Scn2a, mice can perform relatively complex foraging tasks that make use of higher-order neuronal circuits.
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Affiliation(s)
- Selin Schamiloglu
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
| | - Hao Wu
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06511
| | - Mingkang Zhou
- Neuroscience Graduate Program, University of California, San Francisco, CA 94158
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
| | - Alex C Kwan
- Interdepartmental Neuroscience Program, Yale University School of Medicine, New Haven, CT 06511
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14853
| | - Kevin J Bender
- Center for Integrative Neuroscience, Department of Neurology, University of California, San Francisco, CA 94158
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9
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Abe Y, Yagishita S, Sano H, Sugiura Y, Dantsuji M, Suzuki T, Mochizuki A, Yoshimaru D, Hata J, Matsumoto M, Taira S, Takeuchi H, Okano H, Ohno N, Suematsu M, Inoue T, Nambu A, Watanabe M, Tanaka KF. Shared GABA transmission pathology in dopamine agonist- and antagonist-induced dyskinesia. Cell Rep Med 2023; 4:101208. [PMID: 37774703 PMCID: PMC10591040 DOI: 10.1016/j.xcrm.2023.101208] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 08/15/2023] [Accepted: 09/05/2023] [Indexed: 10/01/2023]
Abstract
Dyskinesia is involuntary movement caused by long-term medication with dopamine-related agents: the dopamine agonist 3,4-dihydroxy-L-phenylalanine (L-DOPA) to treat Parkinson's disease (L-DOPA-induced dyskinesia [LID]) or dopamine antagonists to treat schizophrenia (tardive dyskinesia [TD]). However, it remains unknown why distinct types of medications for distinct neuropsychiatric disorders induce similar involuntary movements. Here, we search for a shared structural footprint using magnetic resonance imaging-based macroscopic screening and super-resolution microscopy-based microscopic identification. We identify the enlarged axon terminals of striatal medium spiny neurons in LID and TD model mice. Striatal overexpression of the vesicular gamma-aminobutyric acid transporter (VGAT) is necessary and sufficient for modeling these structural changes; VGAT levels gate the functional and behavioral alterations in dyskinesia models. Our findings indicate that lowered type 2 dopamine receptor signaling with repetitive dopamine fluctuations is a common cause of VGAT overexpression and late-onset dyskinesia formation and that reducing dopamine fluctuation rescues dyskinesia pathology via VGAT downregulation.
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Affiliation(s)
- Yoshifumi Abe
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Sho Yagishita
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hiromi Sano
- Division of System Neurophysiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan; Division of Behavioral Pharmacology, International Center for Brain Science, Fujita Health University, 1-98 Dengakugakubo, Kutsukake-cho, Toyoake, Aichi 470-1192, Japan
| | - Yuki Sugiura
- Department of Biochemistry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Masanori Dantsuji
- Department of Oral Physiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Toru Suzuki
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Ayako Mochizuki
- Department of Oral Physiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Daisuke Yoshimaru
- Division of Regenerative Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan; RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Junichi Hata
- Division of Regenerative Medicine, The Jikei University School of Medicine, 3-25-8 Nishi-Shimbashi, Minato-ku, Tokyo 105-8461, Japan; RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Graduate School of Human Health Sciences, Tokyo Metropolitan University, 7-2-10 Higashiogu, Arakawa-ku, Tokyo 116-8551, Japan
| | - Mami Matsumoto
- Section of Electron Microscopy, Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan; Department of Developmental and Regenerative Neurobiology, Institute of Brain Science, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi 467-8601, Japan
| | - Shu Taira
- Faculty of Food and Agricultural Sciences, Fukushima University, Kanayagawa, Fukushima 960-1248, Japan
| | - Hiroyoshi Takeuchi
- Department of Psychiatry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Hideyuki Okano
- RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan; Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Nobuhiko Ohno
- Division of Histology and Cell Biology, Department of Anatomy, Jichi Medical University School of Medicine, Shimotsuke, Tochigi 329-0498, Japan; Division of Ultrastructural Research, National Institute for Physiological Sciences, Okazaki 444-8787, Japan
| | - Makoto Suematsu
- Department of Biochemistry, Keio University School of Medicine, Tokyo 160-8582, Japan
| | - Tomio Inoue
- Department of Oral Physiology, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
| | - Atsushi Nambu
- Division of System Neurophysiology, National Institute for Physiological Sciences, 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan; Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), 38 Nishigonaka, Myodaiji, Okazaki, Aichi 444-8585, Japan
| | - Masahiko Watanabe
- Department of Anatomy and Embryology, University of Hokkaido, Sapporo, Hokkaido 060-8638, Japan
| | - Kenji F Tanaka
- Division of Brain Sciences, Institute for Advanced Medical Research, Keio University School of Medicine, Tokyo 160-8582, Japan.
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10
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Soeda S, Ito D, Ogushi T, Sano Y, Negoro R, Fujita T, Saito R, Taniura H. Defects in early synaptic formation and neuronal function in Prader-Willi syndrome. Sci Rep 2023; 13:12053. [PMID: 37491450 PMCID: PMC10368700 DOI: 10.1038/s41598-023-39065-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/19/2023] [Indexed: 07/27/2023] Open
Abstract
Prader-Willi syndrome (PWS), which is a complex epigenetic disorder caused by the deficiency of paternally expressed genes in chromosome 15q11-q13, is associated with several psychiatric dimensions, including autism spectrum disorder. We have previously reported that iPS cells derived from PWS patients exhibited aberrant differentiation and transcriptomic dysregulation in differentiated neural stem cells (NSCs) and neurons. Here, we identified SLITRK1 as a downregulated gene in NSCs differentiated from PWS patient iPS cells by RNA sequencing analysis. Because SLITRK1 is involved in synaptogenesis, we focused on the synaptic formation and function of neurons differentiated from PWS patient iPS cells and NDN or MAGEL2 single gene defect mutant iPS cells. Although βIII tubulin expression levels in all the neurons were comparable to the level of differentiation in the control, pre- and postsynaptic markers were significantly lower in PWS and mutant neurons than in control neurons. PSD-95 puncta along βIII tubulin neurites were also decreased. Membrane potential responses were measured while exposed to high K+ stimulation. The neuronal excitabilities in PWS and mutant neurons showed significantly lower intensity than that of control neurons. These functional defects in PWS neurons may reflect phenotypes of neurodevelopmental disorders in PWS.
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Affiliation(s)
- Shuhei Soeda
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan.
| | - Daiki Ito
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Tomoe Ogushi
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Yui Sano
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
| | - Ryosuke Negoro
- Laboratory of Molecular Pharmacokinetics, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Takuya Fujita
- Laboratory of Molecular Pharmacokinetics, College of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga, 525-8577, Japan
| | - Ryo Saito
- Mitsubishi Tanabe Pharma Corporation, Kamoshida, Aoba, Yokohama, 227-0033, Japan
| | - Hideo Taniura
- Laboratory of Neurochemistry, College of Pharmaceutical Sciences, Ritsumeikan University, 1-1-1 Noji Higashi, Kusatsu, Shiga, 525-8577, Japan
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11
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Arancibia-Opazo S, Contreras-Riquelme JS, Sánchez M, Cisternas-Olmedo M, Vidal RL, Martin AJM, Sáez MA. Transcriptional and Histone Acetylation Changes Associated with CRE Elements Expose Key Factors Governing the Regulatory Circuit in the Early Stage of Huntington's Disease Models. Int J Mol Sci 2023; 24:10848. [PMID: 37446028 DOI: 10.3390/ijms241310848] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Huntington's disease (HD) is a disorder caused by an abnormal expansion of trinucleotide CAG repeats within the huntingtin (Htt) gene. Under normal conditions, the CREB Binding Protein interacts with CREB elements and acetylates Lysine 27 of Histone 3 to direct the expression of several genes. However, mutant Htt causes depletion of CBP, which in turn induces altered histone acetylation patterns and transcriptional deregulation. Here, we have studied a differential expression analysis and H3K27ac variation in 4- and 6-week-old R6/2 mice as a model of juvenile HD. The analysis of differential gene expression and acetylation levels were integrated into Gene Regulatory Networks revealing key regulators involved in the altered transcription cascade. Our results show changes in acetylation and gene expression levels that are related to impaired neuronal development, and key regulators clearly defined in 6-week-old mice are proposed to drive the downstream regulatory cascade in HD. Here, we describe the first approach to determine the relationship among epigenetic changes in the early stages of HD. We determined the existence of changes in pre-symptomatic stages of HD as a starting point for early onset indicators of the progression of this disease.
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Affiliation(s)
- Sandra Arancibia-Opazo
- Chromatin, Epigenetic, and Neuroscience Laboratory, Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago 8580745, Chile
- Programa de Doctorado en Genómica Integrativa, Vicerrectoría de Investigación, Universidad Mayor, Santiago 8580745, Chile
- Laboratorio de Redes Biológicas, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Universidad San Sebastián, Santiago 8580704, Chile
| | - J Sebastián Contreras-Riquelme
- Plant Genome Regulation Lab, Centro de Biotecnología Vegetal, Facultad de Ciencias de la Vida, Universidad Andrés Bello, Santiago 8370186, Chile
| | - Mario Sánchez
- Chromatin, Epigenetic, and Neuroscience Laboratory, Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago 8580745, Chile
| | - Marisol Cisternas-Olmedo
- Centro de Biología Integrativa, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile
- Biomedical Neuroscience Institute, University of Chile, Santiago 8380455, Chile
- Center for Geroscience, Brain Health, and Metabolism, Santiago 8380453, Chile
| | - René L Vidal
- Centro de Biología Integrativa, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile
- Biomedical Neuroscience Institute, University of Chile, Santiago 8380455, Chile
- Center for Geroscience, Brain Health, and Metabolism, Santiago 8380453, Chile
- Escuela de Biotecnología, Facultad de Ciencias, Universidad Mayor, Santiago 8580745, Chile
| | - Alberto J M Martin
- Laboratorio de Redes Biológicas, Centro Científico y Tecnológico de Excelencia Ciencia & Vida, Fundación Ciencia & Vida, Universidad San Sebastián, Santiago 8580704, Chile
- Escuela de Ingeniería, Facultad de Ingeniería, Arquitectura y Diseño, Universidad San Sebastián, Santiago 7500000, Chile
| | - Mauricio A Sáez
- Chromatin, Epigenetic, and Neuroscience Laboratory, Centro de Genómica y Bioinformática, Facultad de Ciencias, Ingeniería y Tecnología, Universidad Mayor, Santiago 8580745, Chile
- Centro de Oncología de Precisión, Facultad de Medicina Universidad Mayor, Santiago 7560908, Chile
- Laboratorio de Investigación en Salud de Precisión, Departamento de Procesos Diagnósticos y Evaluación, Facultad de Ciencias de la Salud, Universidad Católica de Temuco, Temuco 4813302, Chile
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12
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Gimenez-Gomez P, Le T, Martin GE. Modulation of neuronal excitability by binge alcohol drinking. Front Mol Neurosci 2023; 16:1098211. [PMID: 36866357 PMCID: PMC9971943 DOI: 10.3389/fnmol.2023.1098211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Accepted: 01/19/2023] [Indexed: 02/16/2023] Open
Abstract
Drug use poses a serious threat to health systems throughout the world. The number of consumers rises every year being alcohol the drug of abuse most consumed causing 3 million deaths (5.3% of all deaths) worldwide and 132.6 million disability-adjusted life years. In this review, we present an up-to-date summary about what is known regarding the global impact of binge alcohol drinking on brains and how it affects the development of cognitive functions, as well as the various preclinical models used to probe its effects on the neurobiology of the brain. This will be followed by a detailed report on the state of our current knowledge of the molecular and cellular mechanisms underlying the effects of binge drinking on neuronal excitability and synaptic plasticity, with an emphasis on brain regions of the meso-cortico limbic neurocircuitry.
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Affiliation(s)
- Pablo Gimenez-Gomez
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
| | - Timmy Le
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
- Graduate Program in Neuroscience, Morningside Graduate School of Biomedical Sciences, UMass Chan Medical School, Worcester, MA, United States
| | - Gilles E. Martin
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, MA, United States
- The Brudnick Neuropsychiatric Research Institute, Worcester, MA, United States
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13
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Higerd-Rusli GP, Tyagi S, Liu S, Dib-Hajj FB, Waxman SG, Dib-Hajj SD. The fates of internalized Na V1.7 channels in sensory neurons: Retrograde cotransport with other ion channels, axon-specific recycling, and degradation. J Biol Chem 2023; 299:102816. [PMID: 36539035 PMCID: PMC9843449 DOI: 10.1016/j.jbc.2022.102816] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 12/05/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022] Open
Abstract
Neuronal function relies on the maintenance of appropriate levels of various ion channels at the cell membrane, which is accomplished by balancing secretory, degradative, and recycling pathways. Neuronal function further depends on membrane specialization through polarized distribution of specific proteins to distinct neuronal compartments such as axons. Voltage-gated sodium channel NaV1.7, a threshold channel for firing action potentials in nociceptors, plays a major role in human pain, and its abundance in the plasma membrane is tightly regulated. We have recently characterized the anterograde axonal trafficking of NaV1.7 channels in Rab6A-positive vesicles, but the fate of internalized channels is not known. Membrane proteins that have undergone endocytosis can be directed into multiple pathways including those for degradation, recycling to the membrane, and transcytosis. Here, we demonstrate NaV1.7 endocytosis and dynein-dependent retrograde trafficking in Rab7-containing late endosomes together with other axonal membrane proteins using real-time imaging of live neurons. We show that some internalized NaV1.7 channels are delivered to lysosomes within the cell body, and that there is no evidence for NaV1.7 transcytosis. In addition, we show that NaV1.7 is recycled specifically to the axonal membrane as opposed to the soma membrane, suggesting a novel mechanism for the development of neuronal polarity. Together, these results shed light on the mechanisms by which neurons maintain excitable membranes and may inform efforts to target ion channel trafficking for the treatment of disorders of excitability.
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Affiliation(s)
- Grant P Higerd-Rusli
- MD/PhD Program, Yale University School of Medicine, New Haven, Connecticut, USA; Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Sidharth Tyagi
- MD/PhD Program, Yale University School of Medicine, New Haven, Connecticut, USA; Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Shujun Liu
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Fadia B Dib-Hajj
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA
| | - Stephen G Waxman
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA.
| | - Sulayman D Dib-Hajj
- Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, USA; Department of Neurology, Yale University School of Medicine, New Haven, Connecticut, USA; Rehabilitation Research Center, Veterans Affairs Connecticut Healthcare System, West Haven, Connecticut, USA.
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14
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Antoine MW. Paradoxical Hyperexcitability in Disorders of Neurodevelopment. Front Mol Neurosci 2022; 15:826679. [PMID: 35571370 PMCID: PMC9102973 DOI: 10.3389/fnmol.2022.826679] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/14/2022] [Indexed: 01/29/2023] Open
Abstract
Autism Spectrum Disorder (ASD), Rett syndrome (RTT) and Angelman Syndrome (AS) are neurodevelopmental disorders (NDDs) that share several clinical characteristics, including displays of repetitive movements, developmental delays, language deficits, intellectual disability, and increased susceptibility to epilepsy. While several reviews address the biological basis of non-seizure-related ASD phenotypes, here, I highlight some shared biological mechanisms that may contribute to increased seizure susceptibility. I focus on genetic studies identifying the anatomical origin of the seizure phenotype in loss-of-function, monogenic, mouse models of these NDDs, combined with insights gained from complementary studies quantifying levels of synaptic excitation and inhibition. Epilepsy is characterized by a sudden, abnormal increase in synchronous activity within neuronal networks, that is posited to arise from excess excitation, largely driven by reduced synaptic inhibition. Primarily for this reason, elevated network excitability is proposed to underlie the causal basis for the ASD, RTT, and AS phenotypes. Although, mouse models of these disorders replicate aspects of the human condition, i.e., hyperexcitability discharges or seizures on cortical electroencephalograms, measures at the synaptic level often reveal deficits in excitatory synaptic transmission, rather than too much excitation. Resolving this apparent paradox has direct implications regarding expected outcomes of manipulating GABAergic tone. In particular, in NDDs associated with seizures, cortical circuits can display reduced, rather than normal or increased levels of synaptic excitation, and therefore suggested treatments aimed at increasing inhibition could further promote hypoactivity instead of normality. In this review, I highlight shared mechanisms across animal models for ASD, RTT, and AS with reduced synaptic excitation that nevertheless promote hyperexcitability in cortical circuits.
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15
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Xiao Y, Theile JW, Zybura A, Pan Y, Lin Z, Cummins TR. A-type FHFs mediate resurgent currents through TTX-resistant voltage-gated sodium channels. eLife 2022; 11:77558. [PMID: 35441593 PMCID: PMC9071269 DOI: 10.7554/elife.77558] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 04/19/2022] [Indexed: 11/13/2022] Open
Abstract
Resurgent currents (INaR) produced by voltage-gated sodium channels are required for many neurons to maintain high-frequency firing, and contribute to neuronal hyperexcitability and disease pathophysiology. Here we show, for the first time, that INaR can be reconstituted in a heterologous system by co-expression of sodium channel α-subunits and A-type fibroblast growth factor homologous factors (FHFs). Specifically, A-type FHFs induces INaR from Nav1.8, Nav1.9 tetrodotoxin-resistant neuronal channels and, to a lesser extent, neuronal Nav1.7 and cardiac Nav1.5 channels. Moreover, we identified the N-terminus of FHF as the critical molecule responsible for A-type FHFs-mediated INaR. Among the FHFs, FHF4A is the most important isoform for mediating Nav1.8 and Nav1.9 INaR. In nociceptive sensory neurons, FHF4A knockdown significantly reduces INaR amplitude and the percentage of neurons that generate INaR, substantially suppressing excitability. Thus, our work reveals a novel molecular mechanism underlying TTX-resistant INaR generation and provides important potential targets for pain treatment.
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Affiliation(s)
- Yucheng Xiao
- Biology Department, Indiana University - Purdue University Indianapolis, Indianapolis, United States
| | | | - Agnes Zybura
- Paul and Carole Stark Neurosciences Research Institute, Indiana University, Indianapolis, United States
| | - Yanling Pan
- Biology Department, Indiana University - Purdue University Indianapolis, Indianapolis, United States
| | | | - Theodore R Cummins
- Biology Department, Indiana University - Purdue University Indianapolis, Indianapolis, United States
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16
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Ransdell JL, Moreno JD, Bhagavan D, Silva JR, Nerbonne JM. Intrinsic mechanisms in the gating of resurgent Na + currents. eLife 2022; 11:70173. [PMID: 35076394 PMCID: PMC8824471 DOI: 10.7554/elife.70173] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2021] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
The resurgent component of the voltage-gated sodium current (INaR) is a depolarizing conductance, revealed on membrane hyperpolarizations following brief depolarizing voltage steps, which has been shown to contribute to regulating the firing properties of numerous neuronal cell types throughout the central and peripheral nervous systems. Although mediated by the same voltage-gated sodium (Nav) channels that underlie the transient and persistent Nav current components, the gating mechanisms that contribute to the generation of INaR remain unclear. Here, we characterized Nav currents in mouse cerebellar Purkinje neurons, and used tailored voltage-clamp protocols to define how the voltage and the duration of the initial membrane depolarization affect the amplitudes and kinetics of INaR. Using the acquired voltage-clamp data, we developed a novel Markov kinetic state model with parallel (fast and slow) inactivation pathways and, we show that this model reproduces the properties of the resurgent, as well as the transient and persistent, Nav currents recorded in (mouse) cerebellar Purkinje neurons. Based on the acquired experimental data and the simulations, we propose that resurgent Na+ influx occurs as a result of fast inactivating Nav channels transitioning into an open/conducting state on membrane hyperpolarization, and that the decay of INaR reflects the slow accumulation of recovered/opened Nav channels into a second, alternative and more slowly populated, inactivated state. Additional simulations reveal that extrinsic factors that affect the kinetics of fast or slow Nav channel inactivation and/or impact the relative distribution of Nav channels in the fast- and slow-inactivated states, such as the accessory Navβ4 channel subunit, can modulate the amplitude of INaR.
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Affiliation(s)
- Joseph L Ransdell
- Department of Medicine, Washington University in Saint Louis, Saint Louis, United States
| | - Jonathan D Moreno
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, United States
| | - Druv Bhagavan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, United States
| | - Jonathan R Silva
- Department of Biomedical Engineering, Washington University in St. Louis, Saint Louis, United States
| | - Jeanne M Nerbonne
- Department of Medicine, Washington University in Saint Louis, Saint Louis, United States
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17
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Furuta T, Yamauchi K, Okamoto S, Takahashi M, Kakuta S, Ishida Y, Takenaka A, Yoshida A, Uchiyama Y, Koike M, Isa K, Isa T, Hioki H. Multi-scale light microscopy/electron microscopy neuronal imaging from brain to synapse with a tissue clearing method, ScaleSF. iScience 2022; 25:103601. [PMID: 35106459 PMCID: PMC8786651 DOI: 10.1016/j.isci.2021.103601] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 11/19/2021] [Accepted: 12/06/2021] [Indexed: 12/02/2022] Open
Abstract
The mammalian brain is organized over sizes that span several orders of magnitude, from synapses to the entire brain. Thus, a technique to visualize neural circuits across multiple spatial scales (multi-scale neuronal imaging) is vital for deciphering brain-wide connectivity. Here, we developed this technique by coupling successive light microscopy/electron microscopy (LM/EM) imaging with a glutaraldehyde-resistant tissue clearing method, ScaleSF. Our multi-scale neuronal imaging incorporates (1) brain-wide macroscopic observation, (2) mesoscopic circuit mapping, (3) microscopic subcellular imaging, and (4) EM imaging of nanoscopic structures, allowing seamless integration of structural information from the brain to synapses. We applied this technique to three neural circuits of two different species, mouse striatofugal, mouse callosal, and marmoset corticostriatal projection systems, and succeeded in simultaneous interrogation of their circuit structure and synaptic connectivity in a targeted way. Our multi-scale neuronal imaging will significantly advance the understanding of brain-wide connectivity by expanding the scales of objects. Successive light microscopy/electron microscopy in optically cleared tissues Multi-scale neuronal imaging from the entire brain to individual synapses Simultaneous interrogation of neural circuit structure and synaptic connectivity Zooming-in to scarce synaptic contacts with the successive imaging
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Affiliation(s)
- Takahiro Furuta
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kenta Yamauchi
- Department of Neuroanatomy, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Advanced Research Institute for Health Sciences, Juntendo University, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Shinichiro Okamoto
- Department of Neuroanatomy, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Advanced Research Institute for Health Sciences, Juntendo University, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Megumu Takahashi
- Department of Neuroanatomy, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Soichiro Kakuta
- Laboratory of Morphology and Image Analysis, Biomedical Research Core Facilities, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Yoko Ishida
- Department of Neuroanatomy, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Advanced Research Institute for Health Sciences, Juntendo University, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Aya Takenaka
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan
| | - Atsushi Yoshida
- Department of Oral Anatomy and Neurobiology, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Masato Koike
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Advanced Research Institute for Health Sciences, Juntendo University, Bunkyo-Ku, Tokyo 113-8421, Japan
| | - Kaoru Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Tadashi Isa
- Department of Neuroscience, Graduate School of Medicine, Kyoto University, Kyoto, Kyoto 606-8501, Japan
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Kyoto 606-8501, Japan
| | - Hiroyuki Hioki
- Department of Neuroanatomy, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Cell Biology and Neuroscience, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Department of Multi-Scale Brain Structure Imaging, Juntendo University Graduate School of Medicine, Bunkyo-Ku, Tokyo 113-8421, Japan
- Corresponding author
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18
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Yamano R, Miyazaki H, Nukina N. The diffuse distribution of Nav1.2 on mid-axonal regions is a marker for unmyelinated fibers in the central nervous system. Neurosci Res 2021; 177:145-150. [PMID: 34808247 DOI: 10.1016/j.neures.2021.11.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 11/25/2022]
Abstract
Unmyelinated fibers in the central nervous system are known to exist in hippocampal mossy fibers, cerebellar parallel fibers and striatal projection fibers. Previously, we and others reported diffuse distribution of Nav1.2, a voltage-gated sodium channel α-subunit encoded by the SCN2A gene, on unmyelinated striatal projection fibers. Mutations in the SCN2A gene are associated with epilepsies and autism. In this study, we investigated the distribution of Nav1.2 on the unmyelinated fibers in the corpus callosum and stria terminalis by immunohistochemistry and immunoelectron microscopy analysis, suggesting that diffuse localization of Nav1.2 on mid-axonal regions can be a useful marker for unmyelinated fibers.
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Affiliation(s)
- Risa Yamano
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Haruko Miyazaki
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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19
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Zhang J, Chen X, Eaton M, Wu J, Ma Z, Lai S, Park A, Ahmad TS, Que Z, Lee JH, Xiao T, Li Y, Wang Y, Olivero-Acosta MI, Schaber JA, Jayant K, Yuan C, Huang Z, Lanman NA, Skarnes WC, Yang Y. Severe deficiency of the voltage-gated sodium channel Na V1.2 elevates neuronal excitability in adult mice. Cell Rep 2021; 36:109495. [PMID: 34348148 PMCID: PMC8382316 DOI: 10.1016/j.celrep.2021.109495] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 06/30/2021] [Accepted: 07/14/2021] [Indexed: 12/13/2022] Open
Abstract
Scn2a encodes the voltage-gated sodium channel NaV1.2, a main mediator of neuronal action potential firing. The current paradigm suggests that NaV1.2 gain-of-function variants enhance neuronal excitability, resulting in epilepsy, whereas NaV1.2 deficiency impairs neuronal excitability, contributing to autism. However, this paradigm does not explain why ∼20%-30% of individuals with NaV1.2 deficiency still develop seizures. Here, we report the counterintuitive finding that severe NaV1.2 deficiency results in increased neuronal excitability. Using a NaV1.2-deficient mouse model, we show enhanced intrinsic excitability of principal neurons in the prefrontal cortex and striatum, brain regions known to be involved in Scn2a-related seizures. This increased excitability is autonomous and reversible by genetic restoration of Scn2a expression in adult mice. RNA sequencing reveals downregulation of multiple potassium channels, including KV1.1. Correspondingly, KV channel openers alleviate the hyperexcitability of NaV1.2-deficient neurons. This unexpected neuronal hyperexcitability may serve as a cellular basis underlying NaV1.2 deficiency-related seizures.
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Affiliation(s)
- Jingliang Zhang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Xiaoling Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Muriel Eaton
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Jiaxiang Wu
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Zhixiong Ma
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Shirong Lai
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Anthony Park
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Talha S Ahmad
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Zhefu Que
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Ji Hea Lee
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Tiange Xiao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Yuansong Li
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Yujia Wang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Maria I Olivero-Acosta
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - James A Schaber
- Bioscience Imaging Facility, Bindley Bioscience Center, Purdue University, West Lafayette, IN 47907, USA
| | - Krishna Jayant
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA; Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Chongli Yuan
- Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA
| | - Zhuo Huang
- Department of Molecular and Cellular Pharmacology, School of Pharmaceutical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Nadia A Lanman
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA; Purdue Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
| | - William C Skarnes
- The Jackson Laboratory for Genomic Medicine, Farmington, CT 06032, USA
| | - Yang Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, IN 47907, USA; Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA.
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20
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Doray A, Lemoine R, Severin M, Chadet S, Lopez-Charcas O, Héraud A, Baron C, Besson P, Monteil A, Pedersen SF, Roger S. The Voltage-Gated Sodium Channel Beta4 Subunit Maintains Epithelial Phenotype in Mammary Cells. Cells 2021; 10:cells10071624. [PMID: 34209614 PMCID: PMC8304757 DOI: 10.3390/cells10071624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/17/2021] [Accepted: 06/25/2021] [Indexed: 11/16/2022] Open
Abstract
The SCN4B gene, coding for the NaVβ4 subunit of voltage-gated sodium channels, was recently found to be expressed in normal epithelial cells and down-regulated in several cancers. However, its function in normal epithelial cells has not been characterized. In this study, we demonstrated that reducing NaVβ4 expression in MCF10A non-cancer mammary epithelial cells generated important morphological changes observed both in two-dimensional cultures and in three-dimensional cysts. Most notably, the loss of NaVβ4 induced a complete loss of epithelial organisation in cysts and increased proteolytic activity towards the extracellular matrix. Loss of epithelial morphology was associated with an increased degradation of β-catenin, reduced E-cadherin expression and induction of mesenchymal markers N-cadherin, vimentin, and α-SMA expression. Overall, our results suggest that Navβ4 may participate in the maintenance of the epithelial phenotype in mammary cells and that its downregulation might be a determining step in early carcinogenesis.
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Affiliation(s)
- Adélaïde Doray
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Roxane Lemoine
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Marc Severin
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen, Denmark; (M.S.); (S.F.P.)
| | - Stéphanie Chadet
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Osbaldo Lopez-Charcas
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Audrey Héraud
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Christophe Baron
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Pierre Besson
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
| | - Arnaud Monteil
- Institut de Génomique Fonctionnelle, University of Montpellier, CNRS UMR 5203, INSERM U1191, 34094 Montpellier, France;
| | - Stine Falsig Pedersen
- Section for Cell Biology and Physiology, Department of Biology, Faculty of Science, University of Copenhagen, 2100 Copenhagen, Denmark; (M.S.); (S.F.P.)
| | - Sébastien Roger
- Transplantation, Immunologie et Inflammation T2I-EA 4245, Université de Tours, 37044 Tours, France; (A.D.); (R.L.); (S.C.); (O.L.-C.); (A.H.); (C.B.); (P.B.)
- Institut Universitaire de France (IUF), 75231 Paris, France
- Correspondence: ; Tel.: +33-247-36-61-30
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21
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Abstract
Mass spectrometry (MS) is a physical technique used to identify specific chemicals and molecules by precise analysis of their mass and charge; this technology has been adapted for biological sciences applications. Investigators have used MS to identify differential expressions of proteins in Huntington’s disease (HD), to discover Huntingtin (HTT) interacting proteins and to analyze HTT proteoforms. Using systems biology and computational approaches, data from MS screens have been leveraged to find differentially expressed pathways. This review summarizes the data from most of the MS studies done in the HD field in the last 20 years and compares it to the protein data reported before the use of MS technology. The MS results validate early findings in the field such as differential expression of PDE10a and DARPP-32 and identify new changes. We offer a perspective on the MS approach in HD, particularly for identification of disease pathways, the challenges in interpreting data across different studies, and its application to protein studies moving forward.
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Affiliation(s)
- Connor Seeley
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
| | - Kimberly B Kegel-Gleason
- Laboratory of Cellular Neurobiology, Department of Neurology, Massachusetts General Hospital, Charlestown, MA, USA
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22
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Thompson CH, Ben-Shalom R, Bender KJ, George AL. Alternative splicing potentiates dysfunction of early-onset epileptic encephalopathy SCN2A variants. J Gen Physiol 2021; 152:133672. [PMID: 31995133 PMCID: PMC7054859 DOI: 10.1085/jgp.201912442] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 01/07/2020] [Indexed: 01/06/2023] Open
Abstract
Epileptic encephalopathies are severe forms of infantile-onset epilepsy often complicated by severe neurodevelopmental impairments. Some forms of early-onset epileptic encephalopathy (EOEE) have been associated with variants in SCN2A, which encodes the brain voltage-gated sodium channel NaV1.2. Many voltage-gated sodium channel genes, including SCN2A, undergo developmentally regulated mRNA splicing. The early onset of these disorders suggests that developmentally regulated alternative splicing of NaV1.2 may be an important consideration when elucidating the pathophysiological consequences of epilepsy-associated variants. We hypothesized that EOEE-associated NaV1.2 variants would exhibit greater dysfunction in a splice isoform that is prominently expressed during early development. We engineered five EOEE-associated NaV1.2 variants (T236S, E999K, S1336Y, T1623N, and R1882Q) into the adult and neonatal splice isoforms of NaV1.2 and performed whole-cell voltage clamp to elucidate their functional properties. All variants exhibited functional defects that could enhance neuronal excitability. Three of the five variants (T236S, E999K, and S1336Y) exhibited greater dysfunction in the neonatal isoform compared with those observed in the adult isoform. Computational modeling of a developing cortical pyramidal neuron indicated that T236S, E999K, S1336Y, and R1882Q showed hyperexcitability preferentially in immature neurons. These results suggest that both splice isoform and neuronal developmental stage influence how EOEE-associated NaV1.2 variants affect neuronal excitability.
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Affiliation(s)
- Christopher H Thompson
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Roy Ben-Shalom
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Kevin J Bender
- Center for Integrative Neuroscience, Kavli Institute for Fundamental Neuroscience, Department of Neurology, University of California, San Francisco, San Francisco, CA
| | - Alfred L George
- Department of Pharmacology, Northwestern University Feinberg School of Medicine, Chicago, IL
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23
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Deng Y, Wang H, Joni M, Sekhri R, Reiner A. Progression of basal ganglia pathology in heterozygous Q175 knock-in Huntington's disease mice. J Comp Neurol 2021; 529:1327-1371. [PMID: 32869871 PMCID: PMC8049038 DOI: 10.1002/cne.25023] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 08/07/2020] [Accepted: 08/26/2020] [Indexed: 12/29/2022]
Abstract
We used behavioral testing and morphological methods to detail the progression of basal ganglia neuron type-specific pathology and the deficits stemming from them in male heterozygous Q175 mice, compared to age-matched WT males. A rotarod deficit was not present in Q175 mice until 18 months, but increased open field turn rate (reflecting hyperkinesia) and open field anxiety were evident at 6 months. No loss of striatal neurons was seen out to 18 months, but ENK+ and DARPP32+ striatal perikarya were fewer by 6 months, due to diminished expression, with further decline by 18 months. No reduction in SP+ striatal perikarya or striatal interneurons was seen in Q175 mice at 18 months, but cholinergic interneurons showed dendrite attenuation by 6 months. Despite reduced ENK expression in indirect pathway striatal perikarya, ENK-immunostained terminals in globus pallidus externus (GPe) were more abundant at 6 months and remained so out to 18 months. Similarly, SP-immunostained terminals from striatal direct pathway neurons were more abundant in globus pallidus internus and substantia nigra at 6 months and remained so at 18 months. FoxP2+ arkypallidal GPe neurons and subthalamic nucleus neurons were lost by 18 months but not prototypical PARV+ GPe neurons or dopaminergic nigral neurons. Our results show that striatal projection neuron abnormalities and behavioral abnormalities reflecting them develop between 2 and 6 months of age in Q175 male heterozygotes, indicating early effects of the HD mutation. The striatal pathologies resemble those in human HD, but are less severe at 18 months than even in premanifest HD.
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Affiliation(s)
- Yunping Deng
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Hongbing Wang
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Marion Joni
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Radhika Sekhri
- Department of PathologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
| | - Anton Reiner
- Department of Anatomy and NeurobiologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
- Department of OphthalmologyThe University of Tennessee Health Science CenterMemphisTennesseeUSA
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24
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Le Cann K, Foerster A, Rösseler C, Erickson A, Hautvast P, Giesselmann S, Pensold D, Kurth I, Rothermel M, Mattis VB, Zimmer-Bensch G, von Hörsten S, Denecke B, Clarner T, Meents J, Lampert A. The difficulty to model Huntington's disease in vitro using striatal medium spiny neurons differentiated from human induced pluripotent stem cells. Sci Rep 2021; 11:6934. [PMID: 33767215 PMCID: PMC7994641 DOI: 10.1038/s41598-021-85656-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 03/03/2021] [Indexed: 12/21/2022] Open
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by an expanded polyglutamine repeat in the huntingtin gene. The neuropathology of HD is characterized by the decline of a specific neuronal population within the brain, the striatal medium spiny neurons (MSNs). The origins of this extreme vulnerability remain unknown. Human induced pluripotent stem cell (hiPS cell)-derived MSNs represent a powerful tool to study this genetic disease. However, the differentiation protocols published so far show a high heterogeneity of neuronal populations in vitro. Here, we compared two previously published protocols to obtain hiPS cell-derived striatal neurons from both healthy donors and HD patients. Patch-clamp experiments, immunostaining and RT-qPCR were performed to characterize the neurons in culture. While the neurons were mature enough to fire action potentials, a majority failed to express markers typical for MSNs. Voltage-clamp experiments on voltage-gated sodium (Nav) channels revealed a large variability between the two differentiation protocols. Action potential analysis did not reveal changes induced by the HD mutation. This study attempts to demonstrate the current challenges in reproducing data of previously published differentiation protocols and in generating hiPS cell-derived striatal MSNs to model a genetic neurodegenerative disorder in vitro.
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Affiliation(s)
- Kim Le Cann
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Alec Foerster
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Corinna Rösseler
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Andelain Erickson
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | - Petra Hautvast
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany
| | | | - Daniel Pensold
- Institute of Biology II, Division of Functional Epigenetics in the Animal Model, RWTH Aachen University, 52074, Aachen, Germany
| | - Ingo Kurth
- Intitute of Human Genetic, RWTH Aachen University, 52074, Aachen, Germany
| | - Markus Rothermel
- Institute Für Biology II, Department Chemosensation, AG Neuromodulation, 52074, Aachen, Germany
| | - Virginia B Mattis
- Cedars-Sinai Medical Center, Los Angeles, CA, 90048, USA
- Fujifilm Cellular Dynamics, Madison, WI, 53711, USA
| | - Geraldine Zimmer-Bensch
- Institute of Biology II, Division of Functional Epigenetics in the Animal Model, RWTH Aachen University, 52074, Aachen, Germany
| | - Stephan von Hörsten
- Intitute of Virology, Clinical and Molecular Virology, Animal Center of Preclinical Experiments (PETZ), 91054, Erlangen, Germany
| | | | - Tim Clarner
- Intitute for Neuroanatomy, MIT 1, 52074, Aachen, Germany
| | - Jannis Meents
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
- Multi Channel Systems MCS GmbH, Aspenhaustrasse 21, 72770, Reutlingen, Germany.
| | - Angelika Lampert
- Institute of Physiology, RWTH Aachen University, Pauwelsstrasse 30, 52074, Aachen, Germany.
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25
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Crapser JD, Ochaba J, Soni N, Reidling JC, Thompson LM, Green KN. Microglial depletion prevents extracellular matrix changes and striatal volume reduction in a model of Huntington's disease. Brain 2020; 143:266-288. [PMID: 31848580 DOI: 10.1093/brain/awz363] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 08/22/2019] [Accepted: 10/01/2019] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease is associated with a reactive microglial response and consequent inflammation. To address the role of these cells in disease pathogenesis, we depleted microglia from R6/2 mice, a rapidly progressing model of Huntington's disease marked by behavioural impairment, mutant huntingtin (mHTT) accumulation, and early death, through colony-stimulating factor 1 receptor inhibition (CSF1Ri) with pexidartinib (PLX3397) for the duration of disease. Although we observed an interferon gene signature in addition to downregulated neuritogenic and synaptic gene pathways with disease, overt inflammation was not evident by microglial morphology or cytokine transcript levels in R6/2 mice. Nonetheless, CSF1Ri-induced microglial elimination reduced or prevented disease-related grip strength and object recognition deficits, mHTT accumulation, astrogliosis, and striatal volume loss, the latter of which was not associated with reductions in cell number but with the extracellular accumulation of chondroitin sulphate proteoglycans (CSPGs)-a primary component of glial scars. A concurrent loss of proteoglycan-containing perineuronal nets was also evident in R6/2 mice, and microglial elimination not only prevented this but also strikingly increased perineuronal nets in the brains of naïve littermates, suggesting a new role for microglia as homeostatic regulators of perineuronal net formation and integrity.
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Affiliation(s)
- Joshua D Crapser
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Joseph Ochaba
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Neelakshi Soni
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Jack C Reidling
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
| | - Leslie M Thompson
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA.,Department of Psychiatry and Human Behavior, University of California, Irvine, CA, USA
| | - Kim N Green
- Department of Neurobiology and Behavior, University of California, Irvine (UCI), Irvine, CA, USA.,Institute of Memory Impairments and Neurological Disorders, University of California, Irvine, CA, USA
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26
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Miyazaki H, Yamanaka T, Oyama F, Kino Y, Kurosawa M, Yamada-Kurosawa M, Yamano R, Shimogori T, Hattori N, Nukina N. FACS-array-based cell purification yields a specific transcriptome of striatal medium spiny neurons in a murine Huntington disease model. J Biol Chem 2020; 295:9768-9785. [PMID: 32499373 DOI: 10.1074/jbc.ra120.012983] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 05/21/2020] [Indexed: 12/27/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by expanded CAG repeats in the Huntingtin gene. Results from previous studies have suggested that transcriptional dysregulation is one of the key mechanisms underlying striatal medium spiny neuron (MSN) degeneration in HD. However, some of the critical genes involved in HD etiology or pathology could be masked in a common expression profiling assay because of contamination with non-MSN cells. To gain insight into the MSN-specific gene expression changes in presymptomatic R6/2 mice, a common HD mouse model, here we used a transgenic fluorescent protein marker of MSNs for purification via FACS before profiling gene expression with gene microarrays and compared the results of this "FACS-array" with those obtained with homogenized striatal samples (STR-array). We identified hundreds of differentially expressed genes (DEGs) and enhanced detection of MSN-specific DEGs by comparing the results of the FACS-array with those of the STR-array. The gene sets obtained included genes ubiquitously expressed in both MSNs and non-MSN cells of the brain and associated with transcriptional regulation and DNA damage responses. We proposed that the comparative gene expression approach using the FACS-array may be useful for uncovering the gene cascades affected in MSNs during HD pathogenesis.
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Affiliation(s)
- Haruko Miyazaki
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan.,Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, Saitama, Japan.,Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan.,Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, Saitama, Japan.,Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Fumitaka Oyama
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Department of Chemistry and Life Science, Kogakuin University, Tokyo, Japan
| | - Yoshihiro Kino
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Department of Bioinformatics and Molecular Neuropathology, Meiji Pharmaceutical University, Tokyo, Japan
| | - Masaru Kurosawa
- Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Institute for Environmental and Gender-specific Medicine, Juntendo University Graduate School of Medicine, Chiba, Japan
| | | | - Risa Yamano
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, Saitama, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Graduate School of Brain Science, Doshisha University, Kyoto, Japan .,Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Saitama, Japan.,Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, Saitama, Japan.,Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo, Japan
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27
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White HV, Brown ST, Bozza TC, Raman IM. Effects of FGF14 and Na Vβ4 deletion on transient and resurgent Na current in cerebellar Purkinje neurons. J Gen Physiol 2019; 151:1300-1318. [PMID: 31558566 PMCID: PMC6829560 DOI: 10.1085/jgp.201912390] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/03/2019] [Indexed: 11/20/2022] Open
Abstract
Voltage-gated Na channels of Purkinje cells are specialized to maintain high availability during high-frequency repetitive firing. They enter fast-inactivated states relatively slowly and undergo a voltage-dependent open-channel block by an intracellular protein (or proteins) that prevents stable fast inactivation and generates resurgent Na current. These properties depend on the pore-forming α subunits, as well as modulatory subunits within the Na channel complex. The identity of the factors responsible for open-channel block remains a question. Here we investigate the effects of genetic mutation of two Na channel auxiliary subunits highly expressed in Purkinje cells, NaVβ4 and FGF14, on modulating Na channel blocked as well as inactivated states. We find that although both NaVβ4 and the FGF14 splice variant FGF14-1a contain sequences that can generate resurgent-like currents when applied to Na channels in peptide form, deletion of either protein, or both proteins simultaneously, does not eliminate resurgent current in acutely dissociated Purkinje cell bodies. Loss of FGF14 expression does, however, reduce resurgent current amplitude and leads to an acceleration and stabilization of inactivation that is not reversed by application of the site-3 toxin, anemone toxin II (ATX). Tetrodotoxin (TTX) sensitivity is higher for resurgent than transient components of Na current, and loss of FGF14 preferentially affects a highly TTX-sensitive subset of Purkinje α subunits. The data suggest that NaV1.6 channels, which are known to generate the majority of Purkinje cell resurgent current, bind TTX with high affinity and are modulated by FGF14 to facilitate open-channel block.
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Affiliation(s)
- Hayley V White
- Department of Neurobiology, Northwestern University, Evanston, IL.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL
| | - Spencer T Brown
- Department of Neurobiology, Northwestern University, Evanston, IL.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL
| | - Thomas C Bozza
- Department of Neurobiology, Northwestern University, Evanston, IL.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL
| | - Indira M Raman
- Department of Neurobiology, Northwestern University, Evanston, IL .,Northwestern University Interdepartmental Neuroscience Program, Northwestern University, Evanston, IL
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Léna I, Mantegazza M. Na V1.2 haploinsufficiency in Scn2a knock-out mice causes an autistic-like phenotype attenuated with age. Sci Rep 2019; 9:12886. [PMID: 31501495 PMCID: PMC6733925 DOI: 10.1038/s41598-019-49392-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 08/23/2019] [Indexed: 12/11/2022] Open
Abstract
Mutations of the SCN2A gene, encoding the voltage gated sodium channel NaV1.2, have been associated to a wide spectrum of epileptic disorders ranging from benign familial neonatal-infantile seizures to early onset epileptic encephalopathies such as Ohtahara syndrome. These phenotypes may be caused by either gain-of-function or loss-of-function mutations. More recently, loss-of-function SCN2A mutations have also been identified in patients with autism spectrum disorder (ASD) without overt epileptic phenotypes. Heterozygous Scn2a knock-out mice (Scn2a+/−) may be a model of this phenotype. Because ASD develops in childhood, we performed a detailed behavioral characterization of Scn2a+/− mice comparing the juvenile/adolescent period of development and adulthood. We used tasks relevant to ASD and the different comorbidities frequently found in this disorder, such as anxiety or intellectual disability. Our data demonstrate that young Scn2a+/− mice display autistic-like phenotype associated to impaired memory and reduced reactivity to stressful stimuli. Interestingly, these dysfunctions are attenuated with age since adult mice show only communicative deficits. Considering the clinical data available on patients with loss-of-function SCN2A mutations, our results indicate that Scn2a+/− mice constitute an ASD model with construct and face validity during the juvenile/adolescent period of development. However, more information about the clinical features of adult carriers of SCN2A mutations is needed to evaluate comparatively the phenotype of adult Scn2a+/− mice.
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Affiliation(s)
- Isabelle Léna
- Université Côte d'Azur, 660 Route des Lucioles, 06560, Valbonne - Sophia Antipolis, France. .,CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), 660 Route des Lucioles, 06560, Valbonne - Sophia Antipolis, France.
| | - Massimo Mantegazza
- Université Côte d'Azur, 660 Route des Lucioles, 06560, Valbonne - Sophia Antipolis, France. .,CNRS UMR 7275, Institute of Molecular and Cellular Pharmacology (IPMC), 660 Route des Lucioles, 06560, Valbonne - Sophia Antipolis, France. .,Inserm, 660 Route des Lucioles, 06560, Valbonne - Sophia Antipolis, France.
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A Human Induced Pluripotent Stem Cell-Derived Tissue Model of a Cerebral Tract Connecting Two Cortical Regions. iScience 2019; 14:301-311. [PMID: 31006610 PMCID: PMC6489017 DOI: 10.1016/j.isci.2019.03.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 12/13/2018] [Accepted: 03/11/2019] [Indexed: 11/25/2022] Open
Abstract
Cerebral tracts connect separated regions within a brain and serve as fundamental structures that support integrative brain functions. However, understanding the mechanisms of cerebral tract development, macro-circuit formation, and related disorders has been hampered by the lack of an in vitro model. Here, we developed a human stem cell-derived model of cerebral tracts, which is composed of two spheroids of cortical neurons and a robust fascicle of axons linking these spheroids reciprocally. In a microdevice, two spheroids of cerebral neurons extended axons into a microchannel between the spheroids and spontaneously formed an axon fascicle, mimicking a cerebral tract. We found that the formation of axon fascicle was significantly promoted when two spheroids extended axons toward each other compared with axons extended from only one spheroid. The two spheroids were able to communicate electrically through the axon fascicle. This model tissue could facilitate studies of cerebral tract development and diseases. A cerebral tract model was generated from iPS cell-derived cortical spheroids Two spheroids were spontaneously connected with an axon fascicle in a microdevice An axon fascicle electrically connected two cortical spheroids Knockdown of L1CAM disrupted axon fascicle formation in the model tissue
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30
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Tatsukawa T, Raveau M, Ogiwara I, Hattori S, Miyamoto H, Mazaki E, Itohara S, Miyakawa T, Montal M, Yamakawa K. Scn2a haploinsufficient mice display a spectrum of phenotypes affecting anxiety, sociability, memory flexibility and ampakine CX516 rescues their hyperactivity. Mol Autism 2019; 10:15. [PMID: 30962870 PMCID: PMC6437867 DOI: 10.1186/s13229-019-0265-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 03/06/2019] [Indexed: 01/13/2023] Open
Abstract
Background Mutations of the SCN2A gene encoding a voltage-gated sodium channel alpha-II subunit Nav1.2 are associated with neurological disorders such as epilepsy, autism spectrum disorders, intellectual disability, and schizophrenia. However, causal relationships and pathogenic mechanisms underlying these neurological defects, especially social and psychiatric features, remain to be elucidated. Methods We investigated the behavior of mice with a conventional or conditional deletion of Scn2a in a comprehensive test battery including open field, elevated plus maze, light-dark box, three chambers, social dominance tube, resident-intruder, ultrasonic vocalization, and fear conditioning tests. We further monitored the effects of the positive allosteric modulator of AMPA receptors CX516 on these model mice. Results Conventional heterozygous Scn2a knockout mice (Scn2aKO/+) displayed novelty-induced exploratory hyperactivity and increased rearing. The increased vertical activity was reproduced by heterozygous inactivation of Scn2a in dorsal-telencephalic excitatory neurons but not in inhibitory neurons. Moreover, these phenotypes were rescued by treating Scn2aKO/+ mice with CX516. Additionally, Scn2aKO/+ mice displayed mild social behavior impairment, enhanced fear conditioning, and deficient fear extinction. Neuronal activity was intensified in the medial prefrontal cortex of Scn2aKO/+ mice, with an increase in the gamma band. Conclusions Scn2aKO/+ mice exhibit a spectrum of phenotypes commonly observed in models of schizophrenia and autism spectrum disorder. Treatment with the CX516 ampakine, which ameliorates hyperactivity in these mice, could be a potential therapeutic strategy to rescue some of the disease phenotypes. Electronic supplementary material The online version of this article (10.1186/s13229-019-0265-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tetsuya Tatsukawa
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan
| | - Matthieu Raveau
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan
| | - Ikuo Ogiwara
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan.,2Department of Physiology, Nippon Medical School, Bunkyo-ku, Tokyo, 113-8602 Japan
| | - Satoko Hattori
- 3Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake-shi, Aichi 470-1192 Japan
| | - Hiroyuki Miyamoto
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan
| | - Emi Mazaki
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan
| | - Shigeyoshi Itohara
- 4Laboratory for Behavioral Genetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan.,5FIRST, Japan Science and Technology Agency, Kawaguchi, Saitama 332-0012 Japan
| | - Tsuyoshi Miyakawa
- 3Division of Systems Medical Science, Institute for Comprehensive Medical Science, Fujita Health University, Toyoake-shi, Aichi 470-1192 Japan
| | - Mauricio Montal
- 6Section of Neurobiology, Division of Biological Sciences, University of California San Diego, La Jolla, CA 92093 USA
| | - Kazuhiro Yamakawa
- 1Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama 351-0198 Japan
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31
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Blednov YA, Bajo M, Roberts AJ, Da Costa AJ, Black M, Edmunds S, Mayfield J, Roberto M, Homanics GE, Lasek AW, Hitzemann RJ, Harris RA. Scn4b regulates the hypnotic effects of ethanol and other sedative drugs. GENES BRAIN AND BEHAVIOR 2019; 18:e12562. [PMID: 30817077 PMCID: PMC6612599 DOI: 10.1111/gbb.12562] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 02/23/2019] [Accepted: 02/27/2019] [Indexed: 11/28/2022]
Abstract
The voltage-gated sodium channel subunit β4 (SCN4B) regulates neuronal activity by modulating channel gating and has been implicated in ethanol consumption in rodent models and human alcoholics. However, the functional role for Scn4b in ethanol-mediated behaviors is unknown. We determined if genetic global knockout (KO) or targeted knockdown of Scn4b in the central nucleus of the amygdala (CeA) altered ethanol drinking or related behaviors. We used four different ethanol consumption procedures (continuous and intermittent two-bottle choice (2BC), drinking-in-the dark and chronic intermittent ethanol vapor) and found that male and female Scn4b KO mice did not differ from their wild-type (WT) littermates in ethanol consumption in any of the tests. Knockdown of Scn4b mRNA in the CeA also did not alter 2BC ethanol drinking. However, Scn4b KO mice showed longer duration of the loss of righting reflex induced by ethanol, gaboxadol, pentobarbital and ketamine. KO mice showed slower recovery to basal levels of handling-induced convulsions after ethanol injection, which is consistent with the increased sedative effects observed in these mice. However, Scn4b KO mice did not differ in the severity of acute ethanol withdrawal. Acoustic startle responses, ethanol-induced hypothermia and clearance of blood ethanol also did not differ between the genotypes. There were also no functional differences in the membrane properties or excitability of CeA neurons from Scn4b KO and WT mice. Although we found no evidence that Scn4b regulates ethanol consumption in mice, it was involved in the acute hypnotic effects of ethanol and other sedatives.
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Affiliation(s)
- Yuri A Blednov
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Michal Bajo
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California
| | - Amanda J Roberts
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California
| | - Adriana J Da Costa
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Mendy Black
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Stephanie Edmunds
- Department of Behavioral Neuroscience, Oregon Health & Science University, Oregon, Portland
| | - Jody Mayfield
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
| | - Marisa Roberto
- Department of Neuroscience, The Scripps Research Institute, La Jolla, California
| | - Gregg E Homanics
- Department of Anesthesiology & Perioperative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Neurobiology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Department of Pharmacology & Chemical Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Amy W Lasek
- Department of Psychiatry, University of Illinois at Chicago, Chicago, Illinois
| | - Robert J Hitzemann
- Department of Behavioral Neuroscience, Oregon Health & Science University, Oregon, Portland
| | - Robert A Harris
- Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, Texas
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32
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Park H, Miyazaki H, Yamanaka T, Nukina N. Non-coding RNA Neat1 and Abhd11os expressions are dysregulated in medium spiny neurons of Huntington disease model mice. Neurosci Res 2018; 147:58-63. [PMID: 30391555 DOI: 10.1016/j.neures.2018.10.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/30/2018] [Accepted: 10/30/2018] [Indexed: 10/27/2022]
Abstract
Huntington Disease (HD) is a neurodegenerative disorder caused by expanded CAG repeats in the exon1 of huntingtin gene (HTT). The mutant HTT affects the transcriptional profile of neurons by disrupting the activities of transcriptional machinery and alters expression of many genes. In this study, we identified dysregulated non-coding RNAs (ncRNAs) in medium spiny neurons of 4-week-old HD model mouse. Also, we observed the intracellular localizations of Abhd11os and Neat1 ncRNAs by ViewRNA in situ hybridization, which could provide more precise detection, suggesting that it is a useful method to investigate the expression changes of genes with low expression levels.
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Affiliation(s)
- Hongsun Park
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Haruko Miyazaki
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Nobuyuki Nukina
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Miyakodanitatara, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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33
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Taguchi K, Watanabe Y, Tsujimura A, Tanaka M. Expression of α-synuclein is regulated in a neuronal cell type-dependent manner. Anat Sci Int 2018; 94:11-22. [PMID: 30362073 PMCID: PMC6315015 DOI: 10.1007/s12565-018-0464-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 10/14/2018] [Indexed: 12/15/2022]
Abstract
α-Synuclein, the major component of Lewy bodies (LBs) and Lewy neurites (LNs), is expressed in presynapses under physiologically normal conditions and is involved in synaptic function. Abnormal intracellular aggregates of misfolded α-synuclein such as LBs and LNs are pathological hallmarks of synucleinopathies, including Parkinson’s disease (PD) and dementia with Lewy bodies (DLB). According to previous studies using pathological models overexpressing α-synuclein, high expression of this protein in neurons is a critical risk factor for neurodegeneration. Therefore, it is important to know the endogenous expression levels of α-synuclein in each neuronal cell type. We previously reported differential expression profiles of α-synuclein in vitro and in vivo. In the wild-type mouse brain, particularly in vulnerable regions affected during the progression of idiopathic PD, α-synuclein is highly expressed in neuronal cell bodies of some early PD-affected regions, such as the olfactory bulb, the dorsal motor nucleus of the vagus, and the substantia nigra pars compacta. Synaptic expression of α-synuclein is mostly accompanied by expression of vesicular glutamate transporter-1, an excitatory synapse marker protein. In contrast, α-synuclein expression in inhibitory synapses differs among brain regions. Recently accumulated evidence indicates the close relationship between differential expression profiles of α-synuclein and selective vulnerability of certain neuronal populations. Further studies on the regulation of α-synuclein expression will help to understand the mechanism of LB pathology and provide an innovative therapeutic strategy to prevent PD and DLB onset.
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Affiliation(s)
- Katsutoshi Taguchi
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Yoshihisa Watanabe
- Department of Basic Geriatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Atsushi Tsujimura
- Department of Basic Geriatrics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan
| | - Masaki Tanaka
- Department of Anatomy and Neurobiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kawaramachi-Hirokoji, Kamikyo-ku, Kyoto, 602-8566, Japan.
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34
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Takata N, Kusayanagi K, Maruyama H, Eitai K, Abo M, Akiyama F, Tajima R, Inaba S, Tanaka KF, Mimura M, Sanaka K. Visualization of myelinated fiber bundles orientation during brain slice preparation by reflection polarized light microscopy. Microsc Res Tech 2018; 81:1366-1373. [PMID: 30351467 DOI: 10.1002/jemt.23077] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2018] [Revised: 05/08/2018] [Accepted: 06/01/2018] [Indexed: 11/10/2022]
Abstract
Polarized light imaging (PLI) enables detecting the orientation of myelinated axon bundles in brain slices at microscopic resolution without histological staining. However, standard PLI requires labor-intensive procedures such as mounting brain cryosections on slide glasses. We developed an optical system that does not require a mounting procedure for PLI. Specifically, we developed an optical system to perform PLI in reflection mode (rPLI) instead of employing transmitted light as in standard PLI. We integrated this rPLI system with a conventional vibratome slicer whose cutting blade surface is a mirror. This combination allowed PLI measurements directly during the slicing procedure at room temperature. Thus, mounting procedure for PLI is not necessary. As a proof-of-concept experiment, a perfusion-fixed brain of a mouse was embedded in gelatin-containing agar and cut serially at 40~200 μm intervals. The slicing procedure was temporarily halted after each cut to capture the PLI images of the slice on the reflecting blade surface while the slice was still held up by the agar block. The orientation of the fiber bundle estimated with this method agreed with the results obtained from previous reports. Combination of a popular vibratome slicer and our rPLI system that uses versatile and inexpensive optical components would increase popularity of PLI and facilitates connectome studies at microscopic resolution. RESEARCH HIGHLIGHTS: Polarized light imaging (PLI) of brain slices was realized by using reflected light (rPLI) instead of transmitted light. The rPLI method allows detecting the myelinated fiber bundle orientation during slice preparation.
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Affiliation(s)
- Norio Takata
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Kohei Kusayanagi
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Hironori Maruyama
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Kenji Eitai
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Masaaki Abo
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Fumihiko Akiyama
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Ryo Tajima
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Shinsuke Inaba
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Masaru Mimura
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Kaoru Sanaka
- Department of Physics, Faculty of Science, Tokyo University of Science, Tokyo, Japan
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Ransdell JL, Nerbonne JM. Voltage-gated sodium currents in cerebellar Purkinje neurons: functional and molecular diversity. Cell Mol Life Sci 2018; 75:3495-3505. [PMID: 29982847 PMCID: PMC6123253 DOI: 10.1007/s00018-018-2868-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 06/28/2018] [Accepted: 07/03/2018] [Indexed: 01/09/2023]
Abstract
Purkinje neurons, the sole output of the cerebellar cortex, deliver GABA-mediated inhibition to the deep cerebellar nuclei. To subserve this critical function, Purkinje neurons fire repetitively, and at high frequencies, features that have been linked to the unique properties of the voltage-gated sodium (Nav) channels expressed. In addition to the rapidly activating and inactivating, or transient, component of the Nav current (INaT) present in many types of central and peripheral neurons, Purkinje neurons, also expresses persistent (INaP) and resurgent (INaR) Nav currents. Considerable progress has been made in detailing the biophysical properties and identifying the molecular determinants of these discrete Nav current components, as well as defining their roles in the regulation of Purkinje neuron excitability. Here, we review this important work and highlight the remaining questions about the molecular mechanisms controlling the expression and the functioning of Nav currents in Purkinje neurons. We also discuss the impact of the dynamic regulation of Nav currents on the functioning of individual Purkinje neurons and cerebellar circuits.
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Affiliation(s)
- Joseph L Ransdell
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA
| | - Jeanne M Nerbonne
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63110, USA.
- Department of Medicine, Washington University School of Medicine, Box 8086, 660 South Euclid Avenue, St. Louis, MO, 63110, USA.
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36
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Okuzumi A, Kurosawa M, Hatano T, Takanashi M, Nojiri S, Fukuhara T, Yamanaka T, Miyazaki H, Yoshinaga S, Furukawa Y, Shimogori T, Hattori N, Nukina N. Rapid dissemination of alpha-synuclein seeds through neural circuits in an in-vivo prion-like seeding experiment. Acta Neuropathol Commun 2018; 6:96. [PMID: 30231908 PMCID: PMC6145187 DOI: 10.1186/s40478-018-0587-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/21/2018] [Indexed: 02/26/2023] Open
Abstract
Accumulating evidence suggests that the lesions of Parkinson's disease (PD) expand due to transneuronal spreading of fibrils composed of misfolded alpha-synuclein (a-syn), over the course of 5-10 years. However, the precise mechanisms and the processes underlying the spread of these fibril seeds have not been clarified in vivo. Here, we investigated the speed of a-syn transmission, which has not been a focus of previous a-syn transmission experiments, and whether a-syn pathologies spread in a neural circuit-dependent manner in the mouse brain. We injected a-syn preformed fibrils (PFFs), which are seeds for the propagation of a-syn deposits, either before or after callosotomy, to disconnect bilateral hemispheric connections. In mice that underwent callosotomy before the injection, the propagation of a-syn pathology to the contralateral hemisphere was clearly reduced. In contrast, mice that underwent callosotomy 24 h after a-syn PFFs injection showed a-syn pathology similar to that seen in mice without callosotomy. These results suggest that a-syn seeds are rapidly disseminated through neuronal circuits immediately after seed injection, in a prion-like seeding experiment in vivo, although it is believed that clinical a-syn pathologies take years to spread throughout the brain. In addition, we found that botulinum toxin B blocked the transsynaptic transmission of a-syn seeds by specifically inactivating the synaptic vesicle fusion machinery. This study offers a novel concept regarding a-syn propagation, based on the Braak hypothesis, and also cautions that experimental transmission systems may be examining a unique type of transmission, which differs from the clinical disease state.
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Affiliation(s)
- Ayami Okuzumi
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Masaru Kurosawa
- Institute for Environmental and Gender-specific Medicine, Juntendo University Graduate School of Medicine, 2-1-1 Tomioka, Urayasu-shi, Chiba, 279-0021, Japan
| | - Taku Hatano
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Masashi Takanashi
- Department of Neurology Juntendo University Koshigaya Hospital, 560 Fukuroyama, Koshigaya city, Saitama, 343-0032, Japan
| | - Shuuko Nojiri
- Medical Technology Innovation Center, Clinical Research and Trial Center, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takeshi Fukuhara
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan
| | - Tomoyuki Yamanaka
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Haruko Miyazaki
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Saki Yoshinaga
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan
| | - Yoshiaki Furukawa
- Laboratory for Mechanistic Chemistry of Biomolecules, Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, 223-8522, Japan
| | - Tomomi Shimogori
- Laboratory for Molecular Mechanisms of Brain Development, RIKEN Center for Brain Science, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Nobutaka Hattori
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
| | - Nobuyuki Nukina
- Department of Neurology, Juntendo University Graduate School of Medicine, 2-1-1 Hongo, Bunkyo-ku, Tokyo, 113-8421, Japan.
- Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto, 610-0394, Japan.
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37
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Ferguson LB, Zhang L, Kircher D, Wang S, Mayfield RD, Crabbe JC, Morrisett RA, Harris RA, Ponomarev I. Dissecting Brain Networks Underlying Alcohol Binge Drinking Using a Systems Genomics Approach. Mol Neurobiol 2018; 56:2791-2810. [PMID: 30062672 PMCID: PMC6459809 DOI: 10.1007/s12035-018-1252-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/17/2018] [Indexed: 12/22/2022]
Abstract
Alcohol use disorder (AUD) is a complex psychiatric disorder with strong genetic and environmental risk factors. We studied the molecular perturbations underlying risky drinking behavior by measuring transcriptome changes across the neurocircuitry of addiction in a genetic mouse model of binge drinking. Sixteen generations of selective breeding for high blood alcohol levels after a binge drinking session produced global changes in brain gene expression in alcohol-naïve High Drinking in the Dark (HDID-1) mice. Using gene expression profiles to generate circuit-level hypotheses, we developed a systems approach that integrated regulation of gene coexpression networks across multiple brain regions, neuron-specific transcriptional signatures, and knowledgebase analytics. Whole-cell, voltage-clamp recordings from nucleus accumbens shell neurons projecting to the ventral tegmental area showed differential ethanol-induced plasticity in HDID-1 and control mice and provided support for one of the hypotheses. There were similarities in gene networks between HDID-1 mouse brains and postmortem brains of human alcoholics, suggesting that some gene expression patterns associated with high alcohol consumption are conserved across species. This study demonstrated the value of gene networks for data integration across biological modalities and species to study mechanisms of disease.
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Affiliation(s)
- Laura B Ferguson
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.,The Institute for Neuroscience, The University of Texas at Austin, Austin, TX, USA
| | - Lingling Zhang
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - Daniel Kircher
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - Shi Wang
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - R Dayne Mayfield
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - John C Crabbe
- Portland Alcohol Research Center, VA Portland Health Care System, Portland, OR, USA.,Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | - Richard A Morrisett
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - R Adron Harris
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA
| | - Igor Ponomarev
- The Waggoner Center for Alcohol and Addiction Research, The University of Texas at Austin, Austin, TX, USA.
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Ogiwara I, Miyamoto H, Tatsukawa T, Yamagata T, Nakayama T, Atapour N, Miura E, Mazaki E, Ernst SJ, Cao D, Ohtani H, Itohara S, Yanagawa Y, Montal M, Yuzaki M, Inoue Y, Hensch TK, Noebels JL, Yamakawa K. Nav1.2 haplodeficiency in excitatory neurons causes absence-like seizures in mice. Commun Biol 2018; 1:96. [PMID: 30175250 PMCID: PMC6115194 DOI: 10.1038/s42003-018-0099-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Mutations in the SCN2A gene encoding a voltage-gated sodium channel Nav1.2 are associated with epilepsies, intellectual disability, and autism. SCN2A gain-of-function mutations cause early-onset severe epilepsies, while loss-of-function mutations cause autism with milder and/or later-onset epilepsies. Here we show that both heterozygous Scn2a-knockout and knock-in mice harboring a patient-derived nonsense mutation exhibit ethosuximide-sensitive absence-like seizures associated with spike-and-wave discharges at adult stages. Unexpectedly, identical seizures are reproduced and even more prominent in mice with heterozygous Scn2a deletion specifically in dorsal-telencephalic (e.g., neocortical and hippocampal) excitatory neurons, but are undetected in mice with selective Scn2a deletion in inhibitory neurons. In adult cerebral cortex of wild-type mice, most Nav1.2 is expressed in excitatory neurons with a steady increase and redistribution from proximal (i.e., axon initial segments) to distal axons. These results indicate a pivotal role of Nav1.2 haplodeficiency in excitatory neurons in epilepsies of patients with SCN2A loss-of-function mutations.
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Affiliation(s)
- Ikuo Ogiwara
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Physiology, Nippon Medical School, Tokyo, 113-8602, Japan
| | - Hiroyuki Miyamoto
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,PRESTO, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Tetsuya Tatsukawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Tetsushi Yamagata
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Tojo Nakayama
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Pediatrics, Tohoku University School of Medicine, Sendai, 980-8574, Japan.,Division of Genetics and Genomics, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Nafiseh Atapour
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, VIC, 3050, Australia
| | - Eriko Miura
- Department of Physiology, School of Medicine, Keio University, Tokyo, 160-8582, Japan
| | - Emi Mazaki
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan
| | - Sara J Ernst
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Dezhi Cao
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan.,Neurology Department, Shenzhen Children's Hospital, 518026, Guangdong, China
| | - Hideyuki Ohtani
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Shigeyoshi Itohara
- Laboratory for Behavioral Genetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,FIRST, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi, 371-8511, Japan.,CREST, Japan Science and Technology Agency, Saitama, 332-0012, Japan
| | - Mauricio Montal
- Section of Neurobiology, Division of Biological Sciences, University of California San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Michisuke Yuzaki
- Department of Physiology, School of Medicine, Keio University, Tokyo, 160-8582, Japan
| | - Yushi Inoue
- National Epilepsy Center, Shizuoka Institute of Epilepsy and Neurological Disorders, Shizuoka, 420-8688, Japan
| | - Takao K Hensch
- Laboratory for Neuronal Circuit Development, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.,Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, MA, 02138, USA.,Department of Neurology, FM Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, 02115, USA
| | - Jeffrey L Noebels
- Department of Neurology, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, 77030, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Center for Brain Science, Wako, Saitama, 351-0198, Japan.
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Cathomas F, Azzinnari D, Bergamini G, Sigrist H, Buerge M, Hoop V, Wicki B, Goetze L, Soares S, Kukelova D, Seifritz E, Goebbels S, Nave KA, Ghandour MS, Seoighe C, Hildebrandt T, Leparc G, Klein H, Stupka E, Hengerer B, Pryce CR. Oligodendrocyte gene expression is reduced by and influences effects of chronic social stress in mice. GENES BRAIN AND BEHAVIOR 2018; 18:e12475. [DOI: 10.1111/gbb.12475] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 03/18/2018] [Accepted: 03/19/2018] [Indexed: 12/16/2022]
Affiliation(s)
- F. Cathomas
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
- Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - D. Azzinnari
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
- Neuroscience Center Zurich; University of Zurich and ETH Zurich; Zurich Switzerland
| | - G. Bergamini
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
- Neuroscience Center Zurich; University of Zurich and ETH Zurich; Zurich Switzerland
| | - H. Sigrist
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - M. Buerge
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - V. Hoop
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
- Institute of Human Movement Sciences and Sport; ETH Zurich; Zurich Switzerland
| | - B. Wicki
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - L. Goetze
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - S. Soares
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - D. Kukelova
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - E. Seifritz
- Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
| | - S. Goebbels
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Goettingen Germany
| | - K.-A. Nave
- Department of Neurogenetics; Max Planck Institute of Experimental Medicine; Goettingen Germany
| | - M. S. Ghandour
- Center of Neurochemistry, University of Strasbourg, UMR 7357; Strasbourg France
- Department of Anatomy and Neurobiology; Virginia Commonwealth University; Richmond Virginia
| | - C. Seoighe
- School of Mathematics, Statistics & Applied Mathematics; National University of Ireland; Galway Ireland
| | - T. Hildebrandt
- Target Discovery Germany; Boehringer Ingelheim Pharma GmbH & Co. KG.; Biberach Germany
| | - G. Leparc
- Target Discovery Germany; Boehringer Ingelheim Pharma GmbH & Co. KG.; Biberach Germany
| | - H. Klein
- Target Discovery Germany; Boehringer Ingelheim Pharma GmbH & Co. KG.; Biberach Germany
| | - E. Stupka
- Target Discovery Germany; Boehringer Ingelheim Pharma GmbH & Co. KG.; Biberach Germany
| | - B. Hengerer
- CNS Diseases Research Germany; Boehringer Ingelheim Pharma GmbH & Co. KG.; Biberach Germany
| | - C. R. Pryce
- Preclinical Laboratory for Translational Research into Affective Disorders, Department of Psychiatry, Psychotherapy and Psychosomatics; Psychiatric Hospital, University of Zurich; Zurich Switzerland
- Neuroscience Center Zurich; University of Zurich and ETH Zurich; Zurich Switzerland
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40
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Tanner MR, Pennington MW, Chamberlain BH, Huq R, Gehrmann EJ, Laragione T, Gulko PS, Beeton C. Targeting KCa1.1 Channels with a Scorpion Venom Peptide for the Therapy of Rat Models of Rheumatoid Arthritis. J Pharmacol Exp Ther 2018; 365:227-236. [PMID: 29453198 DOI: 10.1124/jpet.117.245118] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2017] [Accepted: 02/14/2018] [Indexed: 12/21/2022] Open
Abstract
Fibroblast-like synoviocytes (FLSs) are a key cell type involved in rheumatoid arthritis (RA) progression. We previously identified the KCa1.1 potassium channel (Maxi-K, BK, Slo 1, KCNMA1) as a regulator of FLSs and found that KCa1.1 inhibition reduces disease severity in RA animal models. However, systemic KCa1.1 block causes multiple side effects. In this study, we aimed to determine whether the KCa1.1 β1-3-specific venom peptide blocker iberiotoxin (IbTX) reduces disease severity in animal models of RA without inducing major side effects. We used immunohistochemistry to identify IbTX-sensitive KCa1.1 subunits in joints of rats with a model of RA. Patch-clamp and functional assays were used to determine whether IbTX can regulate FLSs through targeting KCa1.1. We then tested the efficacy of IbTX in ameliorating disease in two rat models of RA. Finally, we determined whether IbTX causes side effects including incontinence or tremors in rats, compared with those treated with the small-molecule KCa1.1 blocker paxilline. IbTX-sensitive subunits of KCa1.1 were expressed by FLSs in joints of rats with experimental arthritis. IbTX inhibited KCa1.1 channels expressed by FLSs from patients with RA and by FLSs from rat models of RA and reduced FLS invasiveness. IbTX significantly reduced disease severity in two rat models of RA. Unlike paxilline, IbTX did not induce tremors or incontinence in rats. Overall, IbTX inhibited KCa1.1 channels on FLSs and treated rat models of RA without inducing side effects associated with nonspecific KCa1.1 blockade and could become the basis for the development of a new treatment of RA.
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Affiliation(s)
- Mark R Tanner
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Michael W Pennington
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Brayden H Chamberlain
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Redwan Huq
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Elizabeth J Gehrmann
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Teresina Laragione
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Pércio S Gulko
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
| | - Christine Beeton
- Department of Molecular Physiology and Biophysics (M.R.T., B.H.C., R.H., E.J.G., C.B.), Interdepartmental Graduate Program in Translational Biology and Molecular Medicine (M.R.T.), and Biology of Inflammation Center and Center for Drug Discovery (C.B.), Baylor College of Medicine, Houston, Texas; Peptides International Inc., Louisville, Kentucky (M.W.P.); and Division of Rheumatology, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, New York (T.L., P.S.G.)
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41
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Misonou H. Precise localizations of voltage-gated sodium and potassium channels in neurons. Dev Neurobiol 2017; 78:271-282. [PMID: 29218789 DOI: 10.1002/dneu.22565] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/01/2017] [Accepted: 12/06/2017] [Indexed: 11/08/2022]
Abstract
Neurons are extremely large and complex cells, and they regulate membrane potentials in multiple subcellular compartments using a variety of ion channels. Voltage-gated sodium (Nav) and potassium (Kv) channels are crucial in regulating neuronal membrane excitability owing to their diversity in subtypes, biophysical properties, and localizations. In particular, specific localizations of Nav and Kv channels in specific membrane compartments are essential to achieve a precise control of local membrane excitability. Recent advancement in super-resolution microscopy further substantiated nanoscale localizations of different ion channels in neuronal membranes. New questions arise from these new lines of evidence regarding how Nav and Kv channels are trafficked to a specific location and maintained against lateral diffusion. In this review, the aim is to summarize current information about ion channel localizations at nanoscopic levels and discuss what we can infer regarding the mechanisms. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 271-282, 2018.
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Affiliation(s)
- Hiroaki Misonou
- Graduate School of Brain Science, Doshisha University, Kyoto, Japan
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42
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Hull JM, Isom LL. Voltage-gated sodium channel β subunits: The power outside the pore in brain development and disease. Neuropharmacology 2017; 132:43-57. [PMID: 28927993 DOI: 10.1016/j.neuropharm.2017.09.018] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 07/19/2017] [Accepted: 09/11/2017] [Indexed: 12/19/2022]
Abstract
Voltage gated sodium channels (VGSCs) were first identified in terms of their role in the upstroke of the action potential. The underlying proteins were later identified as saxitoxin and scorpion toxin receptors consisting of α and β subunits. We now know that VGSCs are heterotrimeric complexes consisting of a single pore forming α subunit joined by two β subunits; a noncovalently linked β1 or β3 and a covalently linked β2 or β4 subunit. VGSC α subunits contain all the machinery necessary for channel cell surface expression, ion conduction, voltage sensing, gating, and inactivation, in one central, polytopic, transmembrane protein. VGSC β subunits are more than simple accessories to α subunits. In the more than two decades since the original cloning of β1, our knowledge of their roles in physiology and pathophysiology has expanded immensely. VGSC β subunits are multifunctional. They confer unique gating mechanisms, regulate cellular excitability, affect brain development, confer distinct channel pharmacology, and have functions that are independent of the α subunits. The vast array of functions of these proteins stems from their special station in the channelome: being the only known constituents that are cell adhesion and intra/extracellular signaling molecules in addition to being part of channel complexes. This functional trifecta and how it goes awry demonstrates the power outside the pore in ion channel signaling complexes, broadening the term channelopathy beyond defects in ion conduction. This article is part of the Special Issue entitled 'Channelopathies.'
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Affiliation(s)
- Jacob M Hull
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States
| | - Lori L Isom
- Neuroscience Program and Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, United States.
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43
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Sodium Channel β2 Subunits Prevent Action Potential Propagation Failures at Axonal Branch Points. J Neurosci 2017; 37:9519-9533. [PMID: 28871036 DOI: 10.1523/jneurosci.0891-17.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 12/19/2022] Open
Abstract
Neurotransmitter release depends on voltage-gated Na+ channels (Navs) to propagate an action potential (AP) successfully from the axon hillock to a synaptic terminal. Unmyelinated sections of axon are very diverse structures encompassing branch points and numerous presynaptic terminals with undefined molecular partners of Na+ channels. Using optical recordings of Ca2+ and membrane voltage, we demonstrate here that Na+ channel β2 subunits (Navβ2s) are required to prevent AP propagation failures across the axonal arborization of cultured rat hippocampal neurons (mixed male and female). When Navβ2 expression was reduced, we identified two specific phenotypes: (1) membrane excitability and AP-evoked Ca2+ entry were impaired at synapses and (2) AP propagation was severely compromised with >40% of axonal branches no longer responding to AP-stimulation. We went on to show that a great deal of electrical signaling heterogeneity exists in AP waveforms across the axonal arborization independent of axon morphology. Therefore, Navβ2 is a critical regulator of axonal excitability and synaptic function in unmyelinated axons.SIGNIFICANCE STATEMENT Voltage-gated Ca2+ channels are fulcrums of neurotransmission that convert electrical inputs into chemical outputs in the form of vesicle fusion at synaptic terminals. However, the role of the electrical signal, the presynaptic action potential (AP), in modulating synaptic transmission is less clear. What is the fidelity of a propagating AP waveform in the axon and what molecules shape it throughout the axonal arborization? Our work identifies several new features of AP propagation in unmyelinated axons: (1) branches of a single axonal arborization have variable AP waveforms independent of morphology, (2) Na+ channel β2 subunits modulate AP-evoked Ca2+-influx, and (3) β2 subunits maintain successful AP propagation across the axonal arbor. These findings are relevant to understanding the flow of excitation in the brain.
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44
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Yamagata T, Ogiwara I, Mazaki E, Yanagawa Y, Yamakawa K. Nav1.2 is expressed in caudal ganglionic eminence-derived disinhibitory interneurons: Mutually exclusive distributions of Nav1.1 and Nav1.2. Biochem Biophys Res Commun 2017; 491:1070-1076. [PMID: 28784306 DOI: 10.1016/j.bbrc.2017.08.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Accepted: 08/02/2017] [Indexed: 11/15/2022]
Abstract
Nav1.1 and Nav1.2 are the voltage-gated sodium channel pore-forming alpha I and II subunits, encoded by the genes SCN1A and SCN2A. Although mutations of both genes have similarly been described in patients with epilepsy, autism and/or intellectual disability, their expression sites in brain are largely distinct. Nav1.1 was shown to be expressed dominantly in parvalbumin (PV)-positive or somatostatin (SST)-positive inhibitory neurons and in a sparsely-distributed subpopulation of excitatory neurons. In contrast, Nav1.2 has been reported to be dominantly expressed in excitatory neurons. Here we show that Nav1.2 is also expressed in caudal ganglionic eminence (CGE)-derived inhibitory neurons, and expressions of Nav1.1 and Nav1.2 are mutually-exclusive in many of brain regions including neocortex, hippocampus, cerebellum, striatum and globus pallidus. In neocortex at postnatal day 15, in addition to the expression in excitatory neurons we show that Nav1.2 is expressed in reelin (RLN)-positive/SST-negative inhibitory neurons that are presumably single-bouquet cells because of their cortical layer I-limited distribution, and vasoactive intestinal peptide (VIP)-positive neurons that would be multipolar cell because of their layer I/II margin and layer VI distribution. Although Nav1.2 has previously been reported to be expressed in SST-positive cells, we here show that Nav1.2 is not expressed in either of PV-positive or SST-positive inhibitory neurons. PV-positive and SST-positive inhibitory neurons derive from medial ganglionic eminence (MGE) and innervate excitatory neurons, while VIP-positive and RLN-positive/SST-negative inhibitory neurons derive from CGE, innervate on inhibitory neurons and play disinhibitory roles in the neural network. Our results therefore indicate that, while Nav1.1 is expressed in MEG-derived inhibitory neurons, Nav1.2 is expressed in CGE-derived disinhibitory interneurons in addition to excitatory neurons. These findings should contribute to understanding of the pathology of neurodevelopmental diseases caused by SCN2A mutations.
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Affiliation(s)
- Tetsushi Yamagata
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Ikuo Ogiwara
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan; Department of Physiology, Nippon Medical School, Tokyo 113-8602, Japan
| | - Emi Mazaki
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine, Maebashi 371-8511, Japan
| | - Kazuhiro Yamakawa
- Laboratory for Neurogenetics, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.
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Landmann J, Richter F, Oros-Peusquens AM, Shah NJ, Classen J, Neely GG, Richter A, Penninger JM, Bechmann I. Neuroanatomy of pain-deficiency and cross-modal activation in calcium channel subunit (CACN) α2δ3 knockout mice. Brain Struct Funct 2017; 223:111-130. [PMID: 28733833 DOI: 10.1007/s00429-017-1473-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 07/05/2017] [Indexed: 11/29/2022]
Abstract
The phenotype of calcium channel subunit (CACN) α2δ3 knockout (KO) mice includes sensory cross-activation and deficient pain perception. Sensory cross-activation defines the activation of a sensory cortical region by input from another modality due to reorganization in the brain such as after sensory loss. To obtain mechanistic insight into both phenomena, we employed a comprehensive battery of neuroanatomical techniques. While CACNα2δ3 was ubiquitously expressed in wild-type mice, it was absent in α2δ3 KO animals. Immunostaining of α1A, α1B, and α1E revealed upregulation of N-type and R-type, but not P/Q-type Cav2 channels in cortical neurons of CACNα2δ3 KO mice. Compared to wild-type mice, axonal processes in somatosensory cortex were enhanced, and dendritic processes reduced, in CACNα2δ3 KO mice. Immunohistochemical and MRI analyses, investigating morphology, thalamocortical and intra-/intercortical trajectories, revealed a disparity between projection and commissural fibers with reduction of the number of spatial specificity of thalamocortical projections. L1cam staining revealed wide-ranging projections of thalamocortical fibers reaching both somatosensory/motor and visual cortical areas. Activation (c-fos+) of excitatory and inhibitory neurons suggested that deficient pain perception in α2δ3 KO mice is unlikely to result from cortical disinhibition. Collectively, our data demonstrate that knock out of CACN α2δ3 results in some structural abnormalities whose functional implications converge to dedifferentiation of sensory activation.
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Affiliation(s)
- Julia Landmann
- Institute of Anatomy, University of Leipzig, Oststrasse 25, 04317, Leipzig, Germany.
| | - Franziska Richter
- Department of Veterinary Medicine, Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103, Leipzig, Germany
| | - Ana-Maria Oros-Peusquens
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich, Forschungszentrum Jülich, 52425, Jülich, Germany
| | - N Jon Shah
- Institute of Neuroscience and Medicine (INM-4), Research Centre Jülich, Forschungszentrum Jülich, 52425, Jülich, Germany.,Department of Neurology, Faculty of Medicine, JARA, RWTH Aachen University, Aachen, Germany
| | - Joseph Classen
- Department of Neurology, University of Leipzig, Liebigstrasse 20, 04103, Leipzig, Germany
| | - G Gregory Neely
- Dr. John and Anne Chong Lab for Functional Genomics, Charles Perkins Centre and School of Life & Environmental Sciences, The University of Sydney, 2006, Camperdown, NSW, Australia
| | - Angelika Richter
- Department of Veterinary Medicine, Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103, Leipzig, Germany
| | - Josef M Penninger
- IMBA, Institute of Molecular Biotechnology of the Austrian Academy of Sciences, Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Ingo Bechmann
- Institute of Anatomy, University of Leipzig, Oststrasse 25, 04317, Leipzig, Germany
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46
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Shimizu H, Tosaki A, Ohsawa N, Ishizuka-Katsura Y, Shoji S, Miyazaki H, Oyama F, Terada T, Shirouzu M, Sekine SI, Nukina N, Yokoyama S. Parallel homodimer structures of the extracellular domains of the voltage-gated sodium channel β4 subunit explain its role in cell-cell adhesion. J Biol Chem 2017; 292:13428-13440. [PMID: 28655765 PMCID: PMC5555201 DOI: 10.1074/jbc.m117.786509] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 06/26/2017] [Indexed: 11/06/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are transmembrane proteins required for the generation of action potentials in excitable cells and essential for propagating electrical impulses along nerve cells. VGSCs are complexes of a pore-forming α subunit and auxiliary β subunits, designated as β1/β1B-β4 (encoded by SCN1B-4B, respectively), which also function in cell-cell adhesion. We previously reported the structural basis for the trans homophilic interaction of the β4 subunit, which contributes to its adhesive function. Here, using crystallographic and biochemical analyses, we show that the β4 extracellular domains directly interact with each other in a parallel manner that involves an intermolecular disulfide bond between the unpaired Cys residues (Cys58) in the loop connecting strands B and C and intermolecular hydrophobic and hydrogen-bonding interactions of the N-terminal segments (Ser30-Val35). Under reducing conditions, an N-terminally deleted β4 mutant exhibited decreased cell adhesion compared with the wild type, indicating that the β4 cis dimer contributes to the trans homophilic interaction of β4 in cell-cell adhesion. Furthermore, this mutant exhibited increased association with the α subunit, indicating that the cis dimerization of β4 affects α-β4 complex formation. These observations provide the structural basis for the parallel dimer formation of β4 in VGSCs and reveal its mechanism in cell-cell adhesion.
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Affiliation(s)
- Hideaki Shimizu
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan.,the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Asako Tosaki
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan
| | - Noboru Ohsawa
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Yoshiko Ishizuka-Katsura
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shisako Shoji
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Haruko Miyazaki
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,the Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Fumitaka Oyama
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Chemistry and Life Science, Kogakuin University, Hachioji, Tokyo 192-0015, Japan, and
| | - Takaho Terada
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
| | - Mikako Shirouzu
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Shun-Ichi Sekine
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan.,the RIKEN Center for Life Science Technologies, Tsurumi, Yokohama 230-0045, Japan
| | - Nobuyuki Nukina
- the Laboratory for Structural Neuropathology, RIKEN Brain Science Institute, Wako, Saitama 351-0198, Japan.,the Department of Neuroscience for Neurodegenerative Disorders, Juntendo University Graduate School of Medicine, Tokyo 113-8421, Japan.,the Laboratory of Structural Neuropathology, Doshisha University Graduate School of Brain Science, 1-3 Tatara Miyakodani, Kyotanabe-shi, Kyoto 610-0394, Japan
| | - Shigeyuki Yokoyama
- From the RIKEN Systems and Structural Biology Center, Tsurumi, Yokohama 230-0045, Japan, .,the RIKEN Structural Biology Laboratory, Tsurumi, Yokohama 230-0045, Japan
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47
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Ransdell JL, Dranoff E, Lau B, Lo WL, Donermeyer DL, Allen PM, Nerbonne JM. Loss of Navβ4-Mediated Regulation of Sodium Currents in Adult Purkinje Neurons Disrupts Firing and Impairs Motor Coordination and Balance. Cell Rep 2017; 19:532-544. [PMID: 28423317 PMCID: PMC5473293 DOI: 10.1016/j.celrep.2017.03.068] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Revised: 02/16/2017] [Accepted: 03/22/2017] [Indexed: 11/28/2022] Open
Abstract
The resurgent component of voltage-gated Na+ (Nav) currents, INaR, has been suggested to provide the depolarizing drive for high-frequency firing and to be generated by voltage-dependent Nav channel block (at depolarized potentials) and unblock (at hyperpolarized potentials) by the accessory Navβ4 subunit. To test these hypotheses, we examined the effects of the targeted deletion of Scn4b (Navβ4) on INaR and on repetitive firing in cerebellar Purkinje neurons. We show here that Scn4b-/- animals have deficits in motor coordination and balance and that firing rates in Scn4b-/- Purkinje neurons are markedly attenuated. Acute, in vivo short hairpin RNA (shRNA)-mediated "knockdown" of Navβ4 in adult Purkinje neurons also reduced spontaneous and evoked firing rates. Dynamic clamp-mediated addition of INaR partially rescued firing in Scn4b-/- Purkinje neurons. Voltage-clamp experiments revealed that INaR was reduced (by ∼50%), but not eliminated, in Scn4b-/- Purkinje neurons, revealing that additional mechanisms contribute to generation of INaR.
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Affiliation(s)
- Joseph L Ransdell
- Departments of Developmental Biology and Internal Medicine , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Edward Dranoff
- Departments of Developmental Biology and Internal Medicine , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Brandon Lau
- Departments of Developmental Biology and Internal Medicine , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Wan-Lin Lo
- Department of Pathology and Immunology , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - David L Donermeyer
- Department of Pathology and Immunology , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Paul M Allen
- Department of Pathology and Immunology , Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Jeanne M Nerbonne
- Departments of Developmental Biology and Internal Medicine , Washington University School of Medicine, St. Louis, MO 63110, USA.
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48
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Ji X, Saha S, Gao G, Lasek AW, Homanics GE, Guildford M, Tapper AR, Martin GE. The Sodium Channel β4 Auxiliary Subunit Selectively Controls Long-Term Depression in Core Nucleus Accumbens Medium Spiny Neurons. Front Cell Neurosci 2017; 11:17. [PMID: 28243192 PMCID: PMC5303751 DOI: 10.3389/fncel.2017.00017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 01/19/2017] [Indexed: 12/19/2022] Open
Abstract
Voltage-gated sodium channels are essential for generating the initial rapid depolarization of neuronal membrane potential during action potentials (APs) that enable cell-to-cell communication, the propagation of signals throughout the brain, and the induction of synaptic plasticity. Although all brain neurons express one or several variants coding for the core pore-forming sodium channel α subunit, the expression of the β (β1–4) auxiliary subunits varies greatly. Of particular interest is the β4 subunit, encoded by the Scn4b gene, that is highly expressed in dorsal and ventral (i.e., nucleus accumbens – NAc) striata compared to other brain regions, and that endows sodium channels with unique gating properties. However, its role on neuronal activity, synaptic plasticity, and behaviors related to drugs of abuse remains poorly understood. Combining whole-cell patch-clamp recordings with two-photon calcium imaging in Scn4b knockout (KO) and knockdown mice, we found that Scn4b altered the properties of APs in core accumbens medium spiny neurons (MSNs). These alterations are associated with a reduction of the probability of MSNs to evoke spike-timing-dependent long-term depression (tLTD) and a reduced ability of backpropagating APs to evoke dendritic calcium transients. In contrast, long-term potentiation (tLTP) remained unaffected. Interestingly, we also showed that amphetamine-induced locomotor activity was significantly reduced in male Scn4b KO mice compared to wild-type controls. Taken together, these data indicate that the Scn4b subunit selectively controls tLTD by modulating dendritic calcium transients evoked by backpropagating APs.
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Affiliation(s)
- Xincai Ji
- Department of Psychiatry, The Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester MA, USA
| | - Sucharita Saha
- Department of Psychiatry, The Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester MA, USA
| | - Guangping Gao
- Gene Therapy Center, University of Massachusetts Medical School, Worcester MA, USA
| | - Amy W Lasek
- Department of Psychiatry, University of Illinois at Chicago, Chicago IL, USA
| | - Gregg E Homanics
- Department of Anesthesiology, University of Pittsburgh, Pittsburgh PA, USA
| | - Melissa Guildford
- Department of Psychiatry, The Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester MA, USA
| | - Andrew R Tapper
- Department of Psychiatry, The Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester MA, USA
| | - Gilles E Martin
- Department of Psychiatry, The Brudnick Neuropsychiatric Research Institute, University of Massachusetts Medical School, Worcester MA, USA
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49
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Abstract
Voltage-gated sodium channels are protein complexes comprised of one pore forming α subunit and two, non-pore forming, β subunits. The voltage-gated sodium channel β subunits were originally identified to function as auxiliary subunits, which modulate the gating, kinetics, and localization of the ion channel pore. Since that time, the five β subunits have been shown to play crucial roles as multifunctional signaling molecules involved in cell adhesion, cell migration, neuronal pathfinding, fasciculation, and neurite outgrowth. Here, we provide an overview of the evidence implicating the β subunits in their conducting and non-conducting roles. Mutations in the β subunit genes (SCN1B-SCN4B) have been linked to a variety of diseases. These include cancer, epilepsy, cardiac arrhythmias, sudden infant death syndrome/sudden unexpected death in epilepsy, neuropathic pain, and multiple neurodegenerative disorders. β subunits thus provide novel therapeutic targets for future drug discovery.
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Affiliation(s)
- Alexandra A Bouza
- Department of Pharmacology, University of Michigan Medical School, 2200 MSRBIII, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109-5632, USA
| | - Lori L Isom
- Department of Pharmacology, University of Michigan Medical School, 2301 MSRB III, 1150 W. Medical Center Dr., Ann Arbor, MI, 48109-5632, USA.
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50
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Barbosa C, Xiao Y, Johnson AJ, Xie W, Strong JA, Zhang JM, Cummins TR. FHF2 isoforms differentially regulate Nav1.6-mediated resurgent sodium currents in dorsal root ganglion neurons. Pflugers Arch 2016; 469:195-212. [PMID: 27999940 DOI: 10.1007/s00424-016-1911-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 10/19/2016] [Accepted: 11/20/2016] [Indexed: 10/20/2022]
Abstract
Nav1.6 and Nav1.6-mediated resurgent currents have been implicated in several pain pathologies. However, our knowledge of how fast resurgent currents are modulated in neurons is limited. Our study explored the potential regulation of Nav1.6-mediated resurgent currents by isoforms of fibroblast growth factor homologous factor 2 (FHF2) in an effort to address the gap in our knowledge. FHF2 isoforms colocalize with Nav1.6 in peripheral sensory neurons. Cell line studies suggest that these proteins differentially regulate inactivation. In particular, FHF2A mediates long-term inactivation, a mechanism proposed to compete with the open-channel blocker mechanism that mediates resurgent currents. On the other hand, FHF2B lacks the ability to mediate long-term inactivation and may delay inactivation favoring open-channel block. Based on these observations, we hypothesized that FHF2A limits resurgent currents, whereas FHF2B enhances resurgent currents. Overall, our results suggest that FHF2A negatively regulates fast resurgent current by enhancing long-term inactivation and delaying recovery. In contrast, FHF2B positively regulated resurgent current and did not alter long-term inactivation. Chimeric constructs of FHF2A and Navβ4 (likely the endogenous open channel blocker in sensory neurons) exhibited differential effects on resurgent currents, suggesting that specific regions within FHF2A and Navβ4 have important regulatory functions. Our data also indicate that FHFAs and FHF2B isoform expression are differentially regulated in a radicular pain model and that associated neuronal hyperexcitability is substantially attenuated by a FHFA peptide. As such, these findings suggest that FHF2A and FHF2B regulate resurgent current in sensory neurons and may contribute to hyperexcitability associated with some pain pathologies.
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Affiliation(s)
- Cindy Barbosa
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yucheng Xiao
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Johnson
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA.,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Wenrui Xie
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Judith A Strong
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Jun-Ming Zhang
- Department of Anesthesiology, University of Cincinnati, Cincinnati, OH, USA
| | - Theodore R Cummins
- Department of Pharmacology and Toxicology, Indiana University, Indianapolis, IN, USA. .,Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA. .,Department of Biology, Indiana University - Purdue University Indianapolis, Indianapolis, IN, USA.
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