1
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Asim M, Qianqian G, Waris A, Wang H, Lai Y, Chen X. Unraveling the role of cholecystokinin in epilepsy: Mechanistic insight into neuroplasticity. Neurochem Int 2024; 180:105870. [PMID: 39343303 DOI: 10.1016/j.neuint.2024.105870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2024] [Revised: 09/15/2024] [Accepted: 09/26/2024] [Indexed: 10/01/2024]
Abstract
Epilepsy is a disorder characterized by an imbalance between excitability and inhibition, leading to uncontrolled hyperexcitability of neurons in the central nervous system. Despite the prevalence of epileptic seizures, the underlying mechanisms driving this hyperexcitability remain poorly understood. This review article aims to enhance our understanding of the mechanisms of epilepsy, with a specific focus on the role of cholecystokinin (CCK) in this debilitating disease. We will begin with an introduction to the topic, followed by an examination of the role of GABAergic neurons and the synaptic plasticity mechanisms associated with seizures. As we delve deeper, we will elucidate how CCK and its receptors contribute to seizure behavior. Finally, we will discuss the CCK-dependent synaptic plasticity mechanisms and highlight their potential implications in seizure activity. Through a comprehensive examination of these aspects, this review provides valuable insights into the involvement of CCK and its receptors in epilepsy. By improving our understanding of the mechanisms underlying this condition, particularly the role of CCK, we aim to contribute to the development of more effective treatment strategies.
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Affiliation(s)
- Muhammad Asim
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong; Department of Biomedical Science, City University of Hong Kong, Kowloon Tong, Hong Kong; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science and Innovation, Chinese Academy of Sciences, Hong Kong.
| | - Gao Qianqian
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Abdul Waris
- Department of Biomedical Science, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Huajie Wang
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Yuanying Lai
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Xi Chen
- Department of Neuroscience, City University of Hong Kong, Kowloon Tong, Hong Kong; Department of Biomedical Science, City University of Hong Kong, Kowloon Tong, Hong Kong; Centre for Regenerative Medicine and Health, Hong Kong Institute of Science and Innovation, Chinese Academy of Sciences, Hong Kong
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2
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Philibert CE, Garcia-Marcos M. Smooth operator(s): dialing up and down neurotransmitter responses by G-protein regulators. Trends Cell Biol 2024:S0962-8924(24)00140-5. [PMID: 39054106 DOI: 10.1016/j.tcb.2024.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Revised: 06/19/2024] [Accepted: 07/01/2024] [Indexed: 07/27/2024]
Abstract
G-protein-coupled receptors (GPCRs) are essential mediators of neuromodulation and prominent pharmacological targets. While activation of heterotrimeric G-proteins (Gαβɣ) by GPCRs is essential in this process, much less is known about the postreceptor mechanisms that influence G-protein activity. Neurons express G-protein regulators that shape the amplitude and kinetics of GPCR-mediated synaptic responses. Although many of these operate by directly altering how G-proteins handle guanine-nucleotides enzymatically, recent discoveries have revealed alternative mechanisms by which GPCR-stimulated G-protein responses are modulated at the synapse. In this review, we cover the molecular basis for, and consequences of, the action of two G-protein regulators that do not affect the enzymatic activity of G-proteins directly: Gα inhibitory interacting protein (GINIP), which binds active Gα subunits, and potassium channel tetramerization domain-containing 12 (KCTD12), which binds active Gβγ subunits.
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Affiliation(s)
- Clementine E Philibert
- Department of Biochemistry and Cell Biology, Chobanian and Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry and Cell Biology, Chobanian and Avedisian School of Medicine, Boston University, Boston, MA 02118, USA; Department of Biology, College of Arts and Sciences, Boston University, Boston, MA 02115, USA.
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3
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Luebbers A, Gonzalez-Hernandez AJ, Zhou M, Eyles SJ, Levitz J, Garcia-Marcos M. Dissecting the molecular basis for the modulation of neurotransmitter GPCR signaling by GINIP. Structure 2024; 32:47-59.e7. [PMID: 37989308 PMCID: PMC10872408 DOI: 10.1016/j.str.2023.10.010] [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: 05/04/2023] [Revised: 09/23/2023] [Accepted: 10/25/2023] [Indexed: 11/23/2023]
Abstract
It is well established that G-protein-coupled receptors (GPCRs) stimulated by neurotransmitters are critical for neuromodulation. Much less is known about how heterotrimeric G-protein (Gαβγ) regulation after receptor-mediated activation contributes to neuromodulation. Recent evidence indicates that the neuronal protein GINIP shapes GPCR inhibitory neuromodulation via a unique mechanism of G-protein regulation that controls pain and seizure susceptibility. However, the molecular basis of this mechanism remains ill-defined because the structural determinants of GINIP responsible for binding and regulating G proteins are not known. Here, we combined hydrogen-deuterium exchange mass spectrometry, computational structure predictions, biochemistry, and cell-based biophysical assays to demonstrate an effector-like binding mode of GINIP to Gαi. Specific amino acids of GINIP's PHD domain first loop are essential for G-protein binding and subsequent regulation of Gαi-GTP and Gβγ signaling upon neurotransmitter GPCR stimulation. In summary, these findings shed light onto the molecular basis for a post-receptor mechanism of G-protein regulation that fine-tunes inhibitory neuromodulation.
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Affiliation(s)
- Alex Luebbers
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | | | - Myles Zhou
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Stephen J Eyles
- Mass Spectrometry Core Facility, Institute for Applied Life Sciences (IALS), University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY 10064, USA; Department of Psychiatry, Weill Cornell Medicine, New York, NY 10065, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA.
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4
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Park JC, Luebbers A, Dao M, Semeano A, Nguyen AM, Papakonstantinou MP, Broselid S, Yano H, Martemyanov KA, Garcia-Marcos M. Fine-tuning GPCR-mediated neuromodulation by biasing signaling through different G protein subunits. Mol Cell 2023; 83:2540-2558.e12. [PMID: 37390816 PMCID: PMC10527995 DOI: 10.1016/j.molcel.2023.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/28/2023] [Accepted: 06/02/2023] [Indexed: 07/02/2023]
Abstract
G-protein-coupled receptors (GPCRs) mediate neuromodulation through the activation of heterotrimeric G proteins (Gαβγ). Classical models depict that G protein activation leads to a one-to-one formation of Gα-GTP and Gβγ species. Each of these species propagates signaling by independently acting on effectors, but the mechanisms by which response fidelity is ensured by coordinating Gα and Gβγ responses remain unknown. Here, we reveal a paradigm of G protein regulation whereby the neuronal protein GINIP (Gα inhibitory interacting protein) biases inhibitory GPCR responses to favor Gβγ over Gα signaling. Tight binding of GINIP to Gαi-GTP precludes its association with effectors (adenylyl cyclase) and, simultaneously, with regulator-of-G-protein-signaling (RGS) proteins that accelerate deactivation. As a consequence, Gαi-GTP signaling is dampened, whereas Gβγ signaling is enhanced. We show that this mechanism is essential to prevent the imbalances of neurotransmission that underlie increased seizure susceptibility in mice. Our findings reveal an additional layer of regulation within a quintessential mechanism of signal transduction that sets the tone of neurotransmission.
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Affiliation(s)
- Jong-Chan Park
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Alex Luebbers
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Maria Dao
- U.F. Scripps Biomedical Research, University of Florida, Jupiter, FL 33458, USA
| | - Ana Semeano
- Department of Pharmaceutical Sciences, Center for Drug Discovery, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Anh Minh Nguyen
- Department of Pharmaceutical Sciences, Center for Drug Discovery, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | - Maria P Papakonstantinou
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Stefan Broselid
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Hideaki Yano
- Department of Pharmaceutical Sciences, Center for Drug Discovery, School of Pharmacy and Pharmaceutical Sciences, Bouvé College of Health Sciences, Northeastern University, Boston, MA 02115, USA
| | | | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA.
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5
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Luebbers A, Zhou M, Eyles SJ, Garcia-Marcos M. Dissecting the molecular basis for the modulation of neurotransmitter GPCR signaling by GINIP. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.20.537566. [PMID: 37131787 PMCID: PMC10153262 DOI: 10.1101/2023.04.20.537566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
It is well-established that activation of heterotrimeric G-proteins (Gαβγ) by G-protein-coupled receptors (GPCRs) stimulated by neurotransmitters is a key mechanism underlying neuromodulation. Much less is known about how G-protein regulation after receptor-mediated activation contributes to neuromodulation. Recent evidence indicates that the neuronal protein GINIP shapes GPCR inhibitory neuromodulation via a unique mechanism of G-protein regulation that controls neurological processes like pain and seizure susceptibility. However, the molecular basis of this mechanism remains ill-defined because the structural determinants of GINIP responsible for binding Gαi subunits and regulating G-protein signaling are not known. Here, we combined hydrogen-deuterium exchange mass-spectrometry, protein folding predictions, bioluminescence resonance energy transfer assays, and biochemical experiments to identify the first loop of the PHD domain of GINIP as an obligatory requirement for Gαi binding. Surprisingly, our results support a model in which GINIP undergoes a long-range conformational change to accommodate Gαi binding to this loop. Using cell-based assays, we demonstrate that specific amino acids in the first loop of the PHD domain are essential for the regulation of Gαi-GTP and free Gβγ signaling upon neurotransmitter GPCR stimulation. In summary, these findings shed light onto the molecular basis for a post-receptor mechanism of G-protein regulation that fine-tunes inhibitory neuromodulation.
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Affiliation(s)
- Alex Luebbers
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Myles Zhou
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
| | - Stephen J Eyles
- Mass Spectrometry Core Facility, Institute for Applied Life Sciences (IALS), University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA
- Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA
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6
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Kuramoto T. Positional cloning of rat mutant genes reveals new functions of these genes. Exp Anim 2023; 72:1-8. [PMID: 36058846 PMCID: PMC9978133 DOI: 10.1538/expanim.22-0089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
The laboratory rat (Rattus norvegicus) is a key model organism for biomedical research. Rats can be subjected to strict genetic and environmental controls. The rat's large body size is suitable for both surgical operations and repeated measurements of physiological parameters. These advantages have led to the development of numerous rat models for genetic diseases. Forward genetics is a proven approach for identifying the causative genes of these disease models but requires genome resources including genetic markers and genome sequences. Over the last few decades, rat genome resources have been developed and deposited in bioresource centers, which have enabled us to perform positional cloning in rats. To date, more than 100 disease-related genes have been identified by positional cloning. Since some disease models are more accessible in rats than mice, the identification of causative genes in these models has sometimes led to the discovery of novel functions of genes. As before, various mutant rats are also expected to be discovered and developed as disease models in the future. Thus, the forward genetics continues to be an important approach to find genes involved in disease phenotypes in rats. In this review, I provide an overview the development of rat genome resources and describe examples of positional cloning in rats in which novel gene functions have been identified.
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Affiliation(s)
- Takashi Kuramoto
- Laboratory of Animal Nutrition, Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan
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7
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Hieu HT, Tanaka M, Kuwamura M, Mashimo T, Serikawa T, Kuramoto T. The rat Downunder (Du) coat color mutation is associated with eye anomalies and embryonic lethality and maps to a 3.9-Mb region on chromosome 3. Exp Anim 2023; 72:88-94. [PMID: 36123037 PMCID: PMC9978131 DOI: 10.1538/expanim.22-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Rodent coat color genes have been studied as a bioresource to understand developmental and cellular processes. The Downunder rat is a fancy variety with a marking on its belly that runs from the neck to the breech and appears to mirror the dorsal hooded marking. Here, we established a congenic strain carrying the Downunder (Du) gene in an F344 genetic background. In addition to the ventral marking, Du/+ rats exhibit anophthalmia or microphthalmia with incomplete penetrance. Du/Du embryos die in the early stages of organogenesis. Genetic linkage analysis mapped the Du gene to rat chromosome 3 and haplotype mapping with congenic rats localized the Du locus to a 3.9-Mb region. The Du locus includes two functional genes, glycosyltransferase-like domain-containing 1 (Gtdc1) and zinc finger E-box binding homeobox 2 (Zeb2). Although we found no functional variation within any of Zeb2's exons or intron-exon boundaries, Zeb2 mRNA levels were significantly lower in Du/+ rats compared with wild-type rats. It is known that melanocyte-specific Zeb2 deletion results in the congenital loss of hair pigmentation in mice. Taken together, our results indicate that the Du mutation exerts pleiotropic effects on hair pigmentation, eye morphology, and development. Moreover, the Zeb2 gene is a strong candidate for the Du mutation.
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Affiliation(s)
- Hoang Trung Hieu
- Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan
| | - Miyuu Tanaka
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, 1-58 Rinku-ourai-kita, Izumisano, Osaka 598-8531,
Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Graduate School of Veterinary Science, Osaka Metropolitan University, 1-58 Rinku-ourai-kita, Izumisano, Osaka 598-8531,
Japan
| | - Tomoji Mashimo
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan,Division of Animal Genetics, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Tadao Serikawa
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan,Kyoto Disease Model Institute, The Kyoto Technoscience Center, 14 Yoshida-kawara-cho, Sakyo-ku, Kyoto 606-8305, Japan
| | - Takashi Kuramoto
- Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan,Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
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8
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van Vliet EA, Hildebrand MS, Mills JD, Brennan GP, Eid T, Masino SA, Whittemore V, Bindila L, Wang KK, Patel M, Perucca P, Reid CA. A companion to the preclinical common data elements for genomics, transcriptomics, and epigenomics data in rodent epilepsy models. A report of the TASK3-WG4 omics working group of the ILAE/AES joint translational TASK force. Epilepsia Open 2022. [PMID: 35950645 DOI: 10.1002/epi4.12640] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/22/2022] [Indexed: 11/06/2022] Open
Abstract
The International League Against Epilepsy/American Epilepsy Society (ILAE/AES) Joint Translational Task Force established the TASK3 working groups to create common data elements (CDEs) for various preclinical epilepsy research disciplines. The aim of the CDEs is to improve the standardization of experimental designs across a range of epilepsy research-related methods. Here, we have generated CDE tables with key parameters and case report forms (CRFs) containing the essential contents of the study protocols for genomics, transcriptomics, and epigenomics in rodent models of epilepsy, with a specific focus on adult rats and mice. We discuss the important elements that need to be considered for genomics, transcriptomics, and epigenomics methodologies, providing a rationale for the parameters that should be collected. This is the first in a two-part series of omics papers with the second installment to cover proteomics, lipidomics, and metabolomics in adult rodents.
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Affiliation(s)
- Erwin A van Vliet
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Michael S Hildebrand
- Epilepsy Research Centre, Department of Medicine (Austin Health), The University of Melbourne, Heidelberg, Victoria, Australia
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Victoria, Australia
| | - James D Mills
- Amsterdam UMC location University of Amsterdam, Department of (Neuro)Pathology, Amsterdam Neuroscience, Amsterdam, The Netherlands
| | - Gary P Brennan
- UCD School of Biomolecular and Biomedical Science, Conway Institute, University College Dublin, Dublin, Ireland
- FutureNeuro Research Centre, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Tore Eid
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Susan A Masino
- Neuroscience Program and Psychology Department, Life Sciences Center, Trinity College, Hartford, Connecticut, USA
| | - Vicky Whittemore
- Division of Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland, USA
| | - Laura Bindila
- Clinical Lipidomics Unit, Institute of Physiological Chemistry, University Medical Center of the Johannes Gutenberg University of Mainz, Mainz, Germany
| | - Kevin K Wang
- Department of Emergency Medicine, Psychiatry and Neuroscience, University of Florida, Gainesville, Florida, USA
- Brain Rehabilitation Research Center, Malcom Randall VA Medical Center, North Florida/South Georgia Veterans Health System, Gainesville, Florida, USA
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Aurora, Colorado, USA
| | - Piero Perucca
- Epilepsy Research Centre, Department of Medicine (Austin Health), The University of Melbourne, Heidelberg, Victoria, Australia
- Bladin-Berkovic Comprehensive Epilepsy Program, Austin Health, Heidelberg, Victoria, Australia
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
- Department of Neurology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia
- Department of Neurology, Alfred Health, Melbourne, Victoria, Australia
| | - Christopher A Reid
- Epilepsy Research Centre, Department of Medicine (Austin Health), The University of Melbourne, Heidelberg, Victoria, Australia
- Murdoch Children's Research Institute, The Royal Children's Hospital, Parkville, Victoria, Australia
- Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, Victoria, Australia
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9
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Numakura Y, Uemura R, Tanaka M, Izawa T, Yamate J, Kuramoto T, Kaneko T, Mashimo T, Yamamoto T, Serikawa T, Kuwamura M. PHF24 is expressed in the inhibitory interneurons in rats. Exp Anim 2021; 70:137-143. [PMID: 33115988 PMCID: PMC7887615 DOI: 10.1538/expanim.20-0105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Accepted: 09/29/2020] [Indexed: 11/20/2022] Open
Abstract
Noda epileptic rat (NER) is a mutant model for epilepsy that exhibits spontaneous generalized tonic-clonic seizure. Epileptogenesis of NER remains to be elucidated; but it is detected an insertion of an endogenous retrovirus sequence in intron 2 of the PHD finger protein 24 (Phf24) gene, encoding Gαi-interacting protein (GINIP). Phf24 is a strong candidate gene for epileptogenesis in NER. PHF24 modulates GABAB signaling through interacting with Gαi protein. To clarify the epileptogenesis of NER, we investigated a distribution of PHF24-expressing cells in the central nerve system (CNS). While broad expression of PHF24 was observed in the CNS, characteristic expression was noted in the periglomerular layer of the olfactory bulb and the lamina II of the spinal cord in the control rats. These cells showed co-expression with calbindin or calretinin, inhibitory interneuron markers. In the olfactory bulb, 15.6% and 41.2% of PHF24-positive neurons co-expressed calbindin and calretinin, respectively. Immunoelectron microscopy revealed that PHF24 was located in the presynaptic terminals, synaptic membranes and cytoplasmic matrix of neuronal soma. Our data suggested PHF24 is expressed in the inhibitory interneurons and may play important roles in modulation of the GABAB signaling.
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Affiliation(s)
- Yuki Numakura
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
| | - Risa Uemura
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
| | - Miyuu Tanaka
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
| | - Takeshi Izawa
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
| | - Jyoji Yamate
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
- Department of Animal Science, Faculty of Agriculture, Tokyo University of Agriculture, 1737 Funako, Atsugi, Kanagawa 243-0034, Japan
| | - Takehito Kaneko
- Laboratory of Animal Reproduction and Development, Graduate School of Science and Engineering, Iwate University, 4-35 Ueda, Morioka-shi, Iwate 020-8551, Japan
| | - Tomoji Mashimo
- Division of Animal Genetics, Laboratory Animal Research Center, Institute of Medical Science, the University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Takashi Yamamoto
- Molecular Genetics Laboratory, Graduate School of Integrated Sciences for Life, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Tadao Serikawa
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Yoshidakonoe-cho, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mitsuru Kuwamura
- Laboratory of Veterinary Pathology, Osaka Prefecture University, 1-58 Ourai-kita, Izumisano, Osaka 598-8531, Japan
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10
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Kinboshi M, Ikeda A, Ohno Y. Role of Astrocytic Inwardly Rectifying Potassium (Kir) 4.1 Channels in Epileptogenesis. Front Neurol 2020; 11:626658. [PMID: 33424762 PMCID: PMC7786246 DOI: 10.3389/fneur.2020.626658] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 12/08/2020] [Indexed: 12/25/2022] Open
Abstract
Astrocytes regulate potassium and glutamate homeostasis via inwardly rectifying potassium (Kir) 4.1 channels in synapses, maintaining normal neural excitability. Numerous studies have shown that dysfunction of astrocytic Kir4.1 channels is involved in epileptogenesis in humans and animal models of epilepsy. Specifically, Kir4.1 channel inhibition by KCNJ10 gene mutation or expressional down-regulation increases the extracellular levels of potassium ions and glutamate in synapses and causes hyperexcitation of neurons. Moreover, recent investigations demonstrated that inhibition of Kir4.1 channels facilitates the expression of brain-derived neurotrophic factor (BDNF), an important modulator of epileptogenesis, in astrocytes. In this review, we summarize the current understanding on the role of astrocytic Kir4.1 channels in epileptogenesis, with a focus on functional and expressional changes in Kir4.1 channels and their regulation of BDNF secretion. We also discuss the potential of Kir4.1 channels as a therapeutic target for the prevention of epilepsy.
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Affiliation(s)
- Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan.,Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders and Physiology, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
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11
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Kim H, Yoshihara M, Suyama M. Comparative genomic analysis of inbred rat strains reveals the existence of ancestral polymorphisms. Mamm Genome 2020; 31:86-94. [PMID: 32166433 PMCID: PMC7200647 DOI: 10.1007/s00335-020-09831-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 03/02/2020] [Indexed: 11/25/2022]
Abstract
In an alignment of closely related genomic sequences, the existence of discordant mutation sites, which do not reflect the phylogenetic relationship of the genomes, is often observed. Although these discordant mutation sites are thought to have emerged by ancestral polymorphism or gene flow, their frequency and distribution in the genome have not yet been analyzed in detail. Using the genome sequences of all protein coding genes of 25 inbred rat strains, we analyzed the frequency and genome-wide distribution of the discordant mutation sites. From the comparison of different substrains, it was found that these loci are not substrain specific, but are common among different groups of substrains, suggesting that the discordant sites might have mainly emerged through ancestral polymorphism. It was also revealed that the discordant sites are not uniformly distributed along chromosomes, but are concentrated at certain genomic loci, such as RT1, major histocompatibility complex of rats, and olfactory receptors, indicating that genes known to be highly polymorphic tend to have more discordant sites. Our results also showed that loci with a high density of discordant sites are also rich in heterozygous variants, even though these are inbred strains.
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Affiliation(s)
- Hyeonjeong Kim
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Minako Yoshihara
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812-8582, Japan
| | - Mikita Suyama
- Division of Bioinformatics, Medical Institute of Bioregulation, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka, 812-8582, Japan.
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Serikawa T, Kunisawa N, Shimizu S, Kato M, Alves Iha H, Kinboshi M, Nishikawa H, Shirakawa Y, Voigt B, Nakanishi S, Kuramoto T, Kaneko T, Yamamoto T, Mashimo T, Sasa M, Ohno Y. Increased seizure sensitivity, emotional defects and cognitive impairment in PHD finger protein 24 (Phf24)-null rats. Behav Brain Res 2019; 369:111922. [PMID: 31039378 DOI: 10.1016/j.bbr.2019.111922] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Revised: 04/18/2019] [Accepted: 04/19/2019] [Indexed: 12/18/2022]
Abstract
Phf24 is known as Gαi-interacting protein (GINIP) and is associated with the GABAB receptor. To study the function of Phf24 protein in the central nervous system (CNS), we have newly developed Phf24-null rats and investigated their behavioral phenotypes, especially changes in seizure sensitivity, emotional responses and cognitive functions. Phf24-null rats did not exhibit any spontaneous seizures. However, they showed a higher sensitivity to pentylenetetrazol (PTZ)- or pilocarpine-induced convulsive seizures. Phf24-null rats also showed an elevated susceptibility to kindling development with repeated PTZ treatments, suggesting that Phf24 acts as an inhibitory modulator in epileptogenesis. Although young Phf24-null rats showed normal gross behaviors, elevated spontaneous locomotor activity, especially in terms of the circadian dark period, emotional hyper-reactivity, reduced anxiety behaviors in the elevated plus-maze (EPM) test, and cognitive deficits in the Morris water maze test were explicitly observed at older age (20-week-old). The present results suggest that Phf24 is essential for proper functioning of the CNS, especially in preventing epileptogenesis and controlling emotional and cognitive functions.
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Affiliation(s)
- Tadao Serikawa
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | - Naofumi Kunisawa
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | - Saki Shimizu
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | - Masaki Kato
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | - Higor Alves Iha
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | - Masato Kinboshi
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan
| | | | | | - Birger Voigt
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Satoshi Nakanishi
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Takashi Kuramoto
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Animal Science, Tokyo University of Agriculture, Kanagawa 243-0034, Japan
| | - Takehito Kaneko
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Chemistry and Biological Sciences, Fuculty of Science and Engineering, Iwate University, Iwate 020-8551, Japan
| | - Takashi Yamamoto
- Department of Molecular Genetics, Graduate School of Mathematical and Life Sciences, Hiroshima University, Hiroshima 739-8526, Japan
| | - Tomoji Mashimo
- Institute of Laboratory Animals, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Genome Editing Research and Development Center, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | | | - Yukihiro Ohno
- Department of Pharmacology, Osaka University of Pharmacological Sciences, Osaka 569-1094, Japan.
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