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Araki T, Hiragi T, Kuga N, Luo C, Andoh M, Sugao K, Nagata H, Sasaki T, Ikegaya Y, Koyama R. Microglia induce auditory dysfunction after status epilepticus in mice. Glia 2024; 72:274-288. [PMID: 37746760 DOI: 10.1002/glia.24472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 09/08/2023] [Accepted: 09/14/2023] [Indexed: 09/26/2023]
Abstract
Auditory dysfunction and increased neuronal activity in the auditory pathways have been reported in patients with temporal lobe epilepsy, but the cellular mechanisms involved are unknown. Here, we report that microglia play a role in the disinhibition of auditory pathways after status epilepticus in mice. We found that neuronal activity in the auditory pathways, including the primary auditory cortex and the medial geniculate body (MGB), was increased and auditory discrimination was impaired after status epilepticus. We further demonstrated that microglia reduced inhibitory synapses on MGB relay neurons over an 8-week period after status epilepticus, resulting in auditory pathway hyperactivity. In addition, we found that local removal of microglia from the MGB attenuated the increase in c-Fos+ relay neurons and improved auditory discrimination. These findings reveal that thalamic microglia are involved in auditory dysfunction in epilepsy.
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Affiliation(s)
- Tasuku Araki
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Toshimitsu Hiragi
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Nahoko Kuga
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Cong Luo
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | | | | | - Takuya Sasaki
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Department of Pharmacology, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
- Center for Information and Neural Networks, National Institute of Information and Communications Technology, Osaka, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
- Institute for AI and Beyond, The University of Tokyo, Tokyo, Japan
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Nakagawa-Tamagawa N, Kirino E, Sugao K, Nagata H, Tagawa Y. Involvement of Calcium-Dependent Pathway and β Subunit-Interaction in Neuronal Migration and Callosal Projection Deficits Caused by the Cav1.2 I1166T Mutation in Developing Mouse Neocortex. Front Neurosci 2021; 15:747951. [PMID: 34955712 PMCID: PMC8692569 DOI: 10.3389/fnins.2021.747951] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 11/11/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: Gain-of-function mutations in the L-type Ca2+ channel Cav1.2 cause Timothy syndrome (TS), a multisystem disorder associated with neurologic symptoms, including autism spectrum disorder (ASD), seizures, and intellectual disability. Cav1.2 plays key roles in neural development, and its mutation can affect brain development and connectivity through Ca2+-dependent and -independent mechanisms. Recently, a gain-of-function mutation, I1166T, in Cav1.2 was identified in patients with TS-like disorder. Its channel properties have been analyzed in vitro but in vivo effects of this mutation on brain development remain unexplored. Methods:In utero electroporation was performed on ICR mice at embryonic day 15 to express GFP, wild-type, and mutant Cav1.2 channels into cortical layer 2/3 excitatory neurons in the primary somatosensory area. The brain was fixed at postnatal days 14–16, sliced, and scanned using confocal microscopy. Neuronal migration of electroporated neurons was examined in the cortex of the electroporated hemisphere, and callosal projection was examined in the white matter and contralateral hemisphere. Results: Expression of the I1166T mutant in layer 2/3 neurons caused migration deficits in approximately 20% of electroporated neurons and almost completely diminished axonal arborization in the contralateral hemisphere. Axonal projection in the white matter was not affected. We introduced second mutations onto Cav1.2 I1166T; L745P mutation blocks Ca2+ influx through Cav1.2 channels and inhibits the Ca2+-dependent pathway, and the W440A mutation blocks the interaction of the Cav1.2 α1 subunit to the β subunit. Both second mutations recovered migration and projection. Conclusion: This study demonstrated that the Cav1.2 I1166T mutation could affect two critical steps during cerebrocortical development, migration and axonal projection, in the mouse brain. This is mediated through Ca2+-dependent pathway downstream of Cav1.2 and β subunit-interaction.
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Affiliation(s)
- Nao Nakagawa-Tamagawa
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.,Laboratory for Molecular Analysis of Higher Brain Function, RIKEN Center for Brain Science, Saitama, Japan
| | - Emi Kirino
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
| | - Kohtaroh Sugao
- Platform Technology Research Unit, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Hidetaka Nagata
- Platform Technology Research Unit, Sumitomo Dainippon Pharma Co., Ltd., Osaka, Japan
| | - Yoshiaki Tagawa
- Department of Physiology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan
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Sakamoto H, Ariyoshi T, Kimpara N, Sugao K, Taiko I, Takikawa K, Asanuma D, Namiki S, Hirose K. Synaptic weight set by Munc13-1 supramolecular assemblies. Nat Neurosci 2017; 21:41-49. [DOI: 10.1038/s41593-017-0041-9] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 11/07/2017] [Indexed: 01/03/2023]
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Heller JP, Michaluk P, Sugao K, Rusakov DA. Probing nano-organization of astroglia with multi-color super-resolution microscopy. J Neurosci Res 2017; 95:2159-2171. [PMID: 28151556 DOI: 10.1002/jnr.24026] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 12/12/2016] [Accepted: 12/28/2016] [Indexed: 01/04/2023]
Abstract
Astroglia are essential for brain development, homeostasis, and metabolic support. They also contribute actively to the formation and regulation of synaptic circuits, by successfully handling, integrating, and propagating physiological signals of neural networks. The latter occurs mainly by engaging a versatile mechanism of internal Ca2+ fluctuations and regenerative waves prompting targeted release of signaling molecules into the extracellular space. Astroglia also show substantial structural plasticity associated with age- and use-dependent changes in neural circuitry. However, the underlying cellular mechanisms are poorly understood, mainly because of the extraordinary complex morphology of astroglial compartments on the nanoscopic scale. This complexity largely prevents direct experimental access to astroglial processes, most of which are beyond the diffraction limit of optical microscopy. Here we employed super-resolution microscopy (direct stochastic optical reconstruction microscopy; dSTORM), to visualize astroglial organization on the nanoscale, in culture and in thin brain slices, as an initial step to understand the structural basis of astrocytic nano-physiology. We were able to follow nanoscopic morphology of GFAP-enriched astrocytes, which adapt a flattened shape in culture and a sponge-like structure in situ, with GFAP fibers of varied diameters. We also visualized nanoscopic astrocytic processes using the ubiquitous cytosolic astrocyte marker proteins S100β and glutamine synthetase. Finally, we overexpressed and imaged membrane-targeted pHluorin and lymphocyte-specific protein tyrosine kinase (N-terminal domain) -green fluorescent protein (lck-GFP), to better understand the molecular cascades underlying some common astroglia-targeted fluorescence imaging techniques. The results provide novel, albeit initial, insights into the cellular organization of astroglia on the nanoscale, paving the way for function-specific studies. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Janosch P Heller
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Queen Square House, London WC1N 3BG, United Kingdom
| | - Piotr Michaluk
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Queen Square House, London WC1N 3BG, United Kingdom
| | - Kohtaroh Sugao
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Queen Square House, London WC1N 3BG, United Kingdom.,Molecular Pathophysiology Research, Drug Research Division, Sumitomo Dainippon Pharma Co., Ltd., Tokyo, 104-8356, Japan
| | - Dmitri A Rusakov
- UCL Institute of Neurology, Department of Clinical and Experimental Epilepsy, Queen Square House, London WC1N 3BG, United Kingdom
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Terry-Lorenzo RT, Masuda K, Sugao K, Fang QK, Orsini MA, Sacchi S, Pollegioni L. High-Throughput Screening Strategy Identifies Allosteric, Covalent Human D-Amino Acid Oxidase Inhibitor. ACTA ACUST UNITED AC 2015; 20:1218-31. [DOI: 10.1177/1087057115600413] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/21/2015] [Indexed: 01/14/2023]
Abstract
Genome-wide association studies have linked polymorphisms in the gene G72 to schizophrenia risk in several human populations. Although controversial, biochemical experiments have suggested that the mechanistic link of G72 to schizophrenia is due to the G72 protein product, pLG72, exerting a regulatory effect on human D-amino acid oxidase (hDAAO) activity. In an effort to identify hDAAO inhibitors of novel mechanism of action, we designed a pLG72-directed hDAAO activity assay suitable for high-throughput screening (HTS). During assay development, we confirmed that pLG72 was an inhibitor of hDAAO. Thus, our assay employed an IC20 pLG72 concentration that was high enough to allow dynamic pLG72-hDAAO complexes to form but with sufficient remaining hDAAO activity to measure during an HTS. After conducting an approximately 150,000-compound HTS, we further characterized a class of compound hits that were less potent hDAAO inhibitors when pLG72 was present. Focusing primarily on compound 2 [2-(2,5-dimethylphenyl)-6-fluorobenzo[d]isothiazol-3(2H)-on], we demonstrated that these compounds inhibited hDAAO via an allosteric, covalent mechanism. Although there is significant interest in the therapeutic potential of compound 2 and its analogues, their sensitivity to reducing agents and their capacity to bind cysteines covalently would need to be addressed during therapeutic drug development.
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Affiliation(s)
- Ryan T. Terry-Lorenzo
- Discovery and Preclinical Research Department, Sunovion Pharmaceuticals, Marlborough, MA, USA
| | - Keiki Masuda
- Genomic Science Laboratories, Sumitomo Dainippon Pharma (DSP), Osaka, Japan
| | - Kohtaroh Sugao
- Genomic Science Laboratories, Sumitomo Dainippon Pharma (DSP), Osaka, Japan
| | - Q. Kevin Fang
- Discovery and Preclinical Research Department, Sunovion Pharmaceuticals, Marlborough, MA, USA
| | - Michael A. Orsini
- Discovery and Preclinical Research Department, Sunovion Pharmaceuticals, Marlborough, MA, USA
| | - Silvia Sacchi
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell’Insubria, Varese, Italy, and The Protein Factory, Politecnico di Milano and Università degli Studi dell’Insubria, Milano, Italy
| | - Loredano Pollegioni
- Dipartimento di Biotecnologie e Scienze della Vita, Università degli Studi dell’Insubria, Varese, Italy, and The Protein Factory, Politecnico di Milano and Università degli Studi dell’Insubria, Milano, Italy
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Abstract
RNA interference (RNAi) using small interfering (siRNA) or short hairpin RNA (shRNA) has become the first choice for gene silencing maneuver in mammalian cells. Because different siRNAs of the same gene have variable silencing efficacy and only limited siRNAs are functional, many candidates are necessary to identify optimal siRNAs. We have previously reported a method named enzymatic production of RNAi library (EPRIL), by which a great variety of shRNA expression constructs (RNAi library) can be produced simultaneously from cDNAs of interest. Recently, we have improved this method and developed a more efficient method. We describe in this chapter detailed protocols for the improved version of EPRIL and high-throughput selection of effective shRNA expression constructs from an RNAi library.
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Affiliation(s)
- Kohtaroh Sugao
- Department of Neurobiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Shirane D, Sugao K, Namiki S, Tanabe M, Iino M, Hirose K. Enzymatic production of RNAi libraries from cDNAs. Nat Genet 2004; 36:190-6. [PMID: 14704669 DOI: 10.1038/ng1290] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2003] [Accepted: 12/15/2003] [Indexed: 12/28/2022]
Abstract
RNA interference (RNAi) induced by small interfering (siRNA) or short hairpin RNA (shRNA) is an important research approach in mammalian genetics. Here we describe a technology called enzymatic production of RNAi library (EPRIL) by which cDNAs are converted by a sequence of enzymatic treatments into an RNAi library consisting of a vast array of different shRNA expression constructs. We applied EPRIL to a single cDNA source and prepared an RNAi library consisting of shRNA constructs with various RNAi efficiencies. High-throughput screening allowed us to rapidly identify the best shRNA constructs from the library. We also describe a new selection scheme using the thymidine kinase gene for obtaining efficient shRNA constructs. Furthermore, we show that EPRIL can be applied to constructing an RNAi library from a cDNA library, providing a basis for future whole-genome phenotypic screening of genes.
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Affiliation(s)
- Daisuke Shirane
- Department of Pharmacology, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
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