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Li ZH, Li B, Zhang XY, Zhu JN. Neuropeptides and Their Roles in the Cerebellum. Int J Mol Sci 2024; 25:2332. [PMID: 38397008 PMCID: PMC10889816 DOI: 10.3390/ijms25042332] [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: 01/10/2024] [Revised: 02/08/2024] [Accepted: 02/12/2024] [Indexed: 02/25/2024] Open
Abstract
Although more than 30 different types of neuropeptides have been identified in various cell types and circuits of the cerebellum, their unique functions in the cerebellum remain poorly understood. Given the nature of their diffuse distribution, peptidergic systems are generally assumed to exert a modulatory effect on the cerebellum via adaptively tuning neuronal excitability, synaptic transmission, and synaptic plasticity within cerebellar circuits. Moreover, cerebellar neuropeptides have also been revealed to be involved in the neurogenetic and developmental regulation of the developing cerebellum, including survival, migration, differentiation, and maturation of the Purkinje cells and granule cells in the cerebellar cortex. On the other hand, cerebellar neuropeptides hold a critical position in the pathophysiology and pathogenesis of many cerebellar-related motor and psychiatric disorders, such as cerebellar ataxias and autism. Over the past two decades, a growing body of evidence has indicated neuropeptides as potential therapeutic targets to ameliorate these diseases effectively. Therefore, this review focuses on eight cerebellar neuropeptides that have attracted more attention in recent years and have significant potential for clinical application associated with neurodegenerative and/or neuropsychiatric disorders, including brain-derived neurotrophic factor, corticotropin-releasing factor, angiotensin II, neuropeptide Y, orexin, thyrotropin-releasing hormone, oxytocin, and secretin, which may provide novel insights and a framework for our understanding of cerebellar-related disorders and have implications for novel treatments targeting neuropeptide systems.
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Affiliation(s)
- Zi-Hao Li
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, Nanjing 210023, China; (Z.-H.L.); (J.-N.Z.)
| | - Bin Li
- Women and Children’s Medical Research Center, The First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China
| | - Xiao-Yang Zhang
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, Nanjing 210023, China; (Z.-H.L.); (J.-N.Z.)
- Institute for Brain Sciences, Nanjing University, Nanjing 210023, China
| | - Jing-Ning Zhu
- State Key Laboratory of Pharmaceutical Biotechnology and Department of Physiology, School of Life Sciences, Nanjing University, Nanjing 210023, China; (Z.-H.L.); (J.-N.Z.)
- Institute for Brain Sciences, Nanjing University, Nanjing 210023, China
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2
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Antonini A, Harris SL, Stryker MP. Neurotrophin NT-4/5 Promotes Structural Changes in Neurons of the Developing Visual Cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.20.572693. [PMID: 38187745 PMCID: PMC10769316 DOI: 10.1101/2023.12.20.572693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2024]
Abstract
Current hypotheses on the mechanisms underlying the development and plasticity of the ocular dominance system through competitive interactions between pathways serving the two eyes strongly suggest the involvement of neurotrophins and their high affinity receptors. In the cat, infusion of the tyrosine kinase B ligand (trkB), neurotrophin-4/5 (NT-4/5), abolishes ocular dominance plasticity that follows monocular deprivation (Gillespie et al., 2000), while tyrosine kinase A and C ligands (trkA and trkC) do not have this effect. One interpretation of this finding is that NT-4/5 causes overgrowth and sprouting of thalamocortical and/or corticocortical terminals, leading to promiscuous neuronal connections which override the experience-dependent fine tuning of connections based on correlated activity. The present study tested whether neurons in cortical regions infused with NT-4/5 showed anatomical changes compatible with this hypothesis. Cats at the peak of the critical period received chronic infusion NT-4/5 into visual cortical areas 17/18 via an osmotic minipump. Visual cortical neurons were labeled in fixed slices using the DiOlistics methods (Gan et al., 2000) and analyzed in confocal microscopy. Infusion of NT-4/5 induced a significant increase of spine-like processes on primary dendrites and a distinctive sprouting of protuberances from neuronal somata in all layers. The increase of neuronal membrane was paralleled by an increase in density of the presynaptic marker synaptophysin in infused areas, suggesting an increase in the numbers of synapses. A contingent of these newly formed synapses may feed into inhibitory circuits, as suggested by an increase of GAD-65 immunostaining in NT-4/5 affected areas. These anatomical changes are consistent with the physiological changes in such animals, suggesting that excess trkB neurotrophin can stimulate the formation of promiscuous connections during the critical period.
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Affiliation(s)
- Antonella Antonini
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
| | - Sheri L Harris
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
| | - Michael P Stryker
- Kavli Center for Fundamental Neuroscience, Department of Physiology, University of California, San Francisco, California 94158
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3
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Tsai YY, Shen CL, D D, Tsai CY, Tarn WY. Activation of TrkB signaling mitigates cerebellar anomalies caused by Rbm4-Bdnf deficiency. Commun Biol 2023; 6:910. [PMID: 37670183 PMCID: PMC10480162 DOI: 10.1038/s42003-023-05294-z] [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: 01/15/2023] [Accepted: 08/28/2023] [Indexed: 09/07/2023] Open
Abstract
A molecular and functional link between neurotrophin signaling and cerebellar foliation is lacking. Here we show that constitutive knockout of two homologous genes encoding the RNA binding protein RBM4 results in foliation defects at cerebellar lobules VI-VII and delayed motor learning in mice. Moreover, the features of Rbm4 double knockout (dKO), including impaired differentiation of cerebellar granule cells and dendritic arborization of Purkinje cells, are reminiscent of neurotrophin deficiency. Loss of RBM4 indeed reduced brain-derived neurotrophic factor (BDNF). RBM4 promoted the expression of BDNF and full-length TrkB, implicating RBM4 in efficient BDNF-TrkB signaling. Finally, prenatal supplementation with 7,8-dihydroxyflavone, a TrkB agonist, restored granule cell differentiation, Purkinje cell dendritic complexity and foliation-the intercrural fissure in particular-in the neonatal cerebellum of Rbm4dKO mice, which also showed improved motor learning in adulthood. This study provides evidence that prenatal activation of TrkB signaling ameliorates cerebellar malformation caused by BDNF deficiency.
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Affiliation(s)
- Yu-Young Tsai
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Columbia University in the City of New York, New York, US
| | - Chiu-Lun Shen
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
- Institute of Molecular Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Dhananjaya D
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Ching-Yen Tsai
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan
| | - Woan-Yuh Tarn
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
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4
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Moreno-Jiménez EP, Flor-García M, Hernández-Vivanco A, Terreros-Roncal J, Rodríguez-Moreno CB, Toni N, Méndez P, Llorens-Martín M. GSK-3β orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo. Cell Mol Life Sci 2023; 80:225. [PMID: 37481766 PMCID: PMC10363517 DOI: 10.1007/s00018-023-04874-w] [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: 04/27/2023] [Revised: 06/30/2023] [Accepted: 07/12/2023] [Indexed: 07/25/2023]
Abstract
Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3β) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3β-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3β overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3β is dysregulated.
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Affiliation(s)
- E P Moreno-Jiménez
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CBMSO), Spanish Research Council (CSIC), Universidad Autónoma de Madrid (UAM) (Campus de Cantoblanco), c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - M Flor-García
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CBMSO), Spanish Research Council (CSIC), Universidad Autónoma de Madrid (UAM) (Campus de Cantoblanco), c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - J Terreros-Roncal
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CBMSO), Spanish Research Council (CSIC), Universidad Autónoma de Madrid (UAM) (Campus de Cantoblanco), c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - C B Rodríguez-Moreno
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CBMSO), Spanish Research Council (CSIC), Universidad Autónoma de Madrid (UAM) (Campus de Cantoblanco), c/Nicolás Cabrera 1, 28049, Madrid, Spain
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain
| | - N Toni
- Department of Psychiatry, Center for Psychiatric Neurosciences, , Lausanne University Hospital (CHUV) and University of Lausanne, Lausanne, Switzerland
| | - P Méndez
- Cajal Institute, CSIC, Madrid, Spain
| | - María Llorens-Martín
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CBMSO), Spanish Research Council (CSIC), Universidad Autónoma de Madrid (UAM) (Campus de Cantoblanco), c/Nicolás Cabrera 1, 28049, Madrid, Spain.
- Center for Networked Biomedical Research on Neurodegenerative Diseases (CIBERNED), Madrid, Spain.
- Department of Molecular Biology, Faculty of Sciences, Universidad Autónoma de Madrid, Madrid, Spain.
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5
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Kim M, Jun S, Park H, Tanaka-Yamamoto K, Yamamoto Y. Regulation of cerebellar network development by granule cells and their molecules. Front Mol Neurosci 2023; 16:1236015. [PMID: 37520428 PMCID: PMC10375027 DOI: 10.3389/fnmol.2023.1236015] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 06/27/2023] [Indexed: 08/01/2023] Open
Abstract
The well-organized cerebellar structures and neuronal networks are likely crucial for their functions in motor coordination, motor learning, cognition, and emotion. Such cerebellar structures and neuronal networks are formed during developmental periods through orchestrated mechanisms, which include not only cell-autonomous programs but also interactions between the same or different types of neurons. Cerebellar granule cells (GCs) are the most numerous neurons in the brain and are generated through intensive cell division of GC precursors (GCPs) during postnatal developmental periods. While GCs go through their own developmental processes of proliferation, differentiation, migration, and maturation, they also play a crucial role in cerebellar development. One of the best-characterized contributions is the enlargement and foliation of the cerebellum through massive proliferation of GCPs. In addition to this contribution, studies have shown that immature GCs and GCPs regulate multiple factors in the developing cerebellum, such as the development of other types of cerebellar neurons or the establishment of afferent innervations. These studies have often found impairments of cerebellar development in animals lacking expression of certain molecules in GCs, suggesting that the regulations are mediated by molecules that are secreted from or present in GCs. Given the growing recognition of GCs as regulators of cerebellar development, this review will summarize our current understanding of cerebellar development regulated by GCs and molecules in GCs, based on accumulated studies and recent findings, and will discuss their potential further contributions.
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Affiliation(s)
- Muwoong Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology (UST), Seoul, Republic of Korea
| | - Soyoung Jun
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology (UST), Seoul, Republic of Korea
| | - Heeyoun Park
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
| | - Keiko Tanaka-Yamamoto
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
- Division of Bio-Medical Science and Technology, KIST School, University of Science and Technology (UST), Seoul, Republic of Korea
| | - Yukio Yamamoto
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul, Republic of Korea
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Boxy P, Nykjær A, Kisiswa L. Building better brains: the pleiotropic function of neurotrophic factors in postnatal cerebellar development. Front Mol Neurosci 2023; 16:1181397. [PMID: 37251644 PMCID: PMC10213292 DOI: 10.3389/fnmol.2023.1181397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 04/26/2023] [Indexed: 05/31/2023] Open
Abstract
The cerebellum is a multifunctional brain region that controls diverse motor and non-motor behaviors. As a result, impairments in the cerebellar architecture and circuitry lead to a vast array of neuropsychiatric and neurodevelopmental disorders. Neurotrophins and neurotrophic growth factors play essential roles in the development as well as maintenance of the central and peripheral nervous system which is crucial for normal brain function. Their timely expression throughout embryonic and postnatal stages is important for promoting growth and survival of both neurons and glial cells. During postnatal development, the cerebellum undergoes changes in its cellular organization, which is regulated by a variety of molecular factors, including neurotrophic factors. Studies have shown that these factors and their receptors promote proper formation of the cerebellar cytoarchitecture as well as maintenance of the cerebellar circuits. In this review, we will summarize what is known on the neurotrophic factors' role in cerebellar postnatal development and how their dysregulation assists in developing various neurological disorders. Understanding the expression patterns and signaling mechanisms of these factors and their receptors is crucial for elucidating their function within the cerebellum and for developing therapeutic strategies for cerebellar-related disorders.
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Affiliation(s)
- Pia Boxy
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience (DANDRITE)–Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus, Denmark
- The Danish National Research Foundation Center, PROMEMO, Aarhus University, Aarhus, Denmark
| | - Anders Nykjær
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience (DANDRITE)–Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus, Denmark
- The Danish National Research Foundation Center, PROMEMO, Aarhus University, Aarhus, Denmark
| | - Lilian Kisiswa
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
- Danish Research Institute of Translational Neuroscience (DANDRITE)–Nordic EMBL Partnership for Molecular Medicine, Aarhus University, Aarhus, Denmark
- The Danish National Research Foundation Center, PROMEMO, Aarhus University, Aarhus, Denmark
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7
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Llorca A, Deogracias R. Origin, Development, and Synaptogenesis of Cortical Interneurons. Front Neurosci 2022; 16:929469. [PMID: 35833090 PMCID: PMC9272671 DOI: 10.3389/fnins.2022.929469] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/01/2022] [Indexed: 11/13/2022] Open
Abstract
The mammalian cerebral cortex represents one of the most recent and astonishing inventions of nature, responsible of a large diversity of functions that range from sensory processing to high-order cognitive abilities, such as logical reasoning or language. Decades of dedicated study have contributed to our current understanding of this structure, both at structural and functional levels. A key feature of the neocortex is its outstanding richness in cell diversity, composed by multiple types of long-range projecting neurons and locally connecting interneurons. In this review, we will describe the great diversity of interneurons that constitute local neocortical circuits and summarize the mechanisms underlying their development and their assembly into functional networks.
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Affiliation(s)
- Alfredo Llorca
- Visual Neuroscience Laboratory, Centre for Discovery Brain Sciences, School of Biomedical Sciences, University of Edinburgh, Edinburg, United Kingdom
- *Correspondence: Alfredo Llorca
| | - Ruben Deogracias
- Neuronal Circuits Formation and Brain Disorders Laboratory, Institute of Neurosciences of Castilla y León (INCyL), University of Salamanca, Salamanca, Spain
- Institute of Biomedical Research of Salamanca, Salamanca, Spain
- Department of Cell Biology and Pathology, School of Medicine, University of Salamanca, Salamanca, Spain
- Ruben Deogracias
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8
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Mitre M, Saadipour K, Williams K, Khatri L, Froemke RC, Chao MV. Transactivation of TrkB Receptors by Oxytocin and Its G Protein-Coupled Receptor. Front Mol Neurosci 2022; 15:891537. [PMID: 35721318 PMCID: PMC9201241 DOI: 10.3389/fnmol.2022.891537] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/11/2022] [Indexed: 12/28/2022] Open
Abstract
Brain-derived Neurotrophic Factor (BDNF) binds to the TrkB tyrosine kinase receptor, which dictates the sensitivity of neurons to BDNF. A unique feature of TrkB is the ability to be activated by small molecules in a process called transactivation. Here we report that the brain neuropeptide oxytocin increases BDNF TrkB activity in primary cortical neurons and in the mammalian neocortex during postnatal development. Oxytocin produces its effects through a G protein-coupled receptor (GPCR), however, the receptor signaling events that account for its actions have not been fully defined. We find oxytocin rapidly transactivates TrkB receptors in bath application of acute brain slices of 2-week-old mice and in primary cortical culture by increasing TrkB receptor tyrosine phosphorylation. The effects of oxytocin signaling could be distinguished from the related vasopressin receptor. The transactivation of TrkB receptors by oxytocin enhances the clustering of gephyrin, a scaffold protein responsible to coordinate inhibitory responses. Because oxytocin displays pro-social functions in maternal care, cognition, and social attachment, it is currently a focus of therapeutic strategies in autism spectrum disorders. Interestingly, oxytocin and BDNF are both implicated in the pathophysiology of depression, schizophrenia, anxiety, and cognition. These results imply that oxytocin may rely upon crosstalk with BDNF signaling to facilitate its actions through receptor transactivation.
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Affiliation(s)
- Mariela Mitre
- Departments of Cell Biology, Neuroscience & Physiology, and Psychiatry, Skirball Institute for Biomolecular Medicine, New York, NY, United States
- Neuroscience Institute, New York University Langone Medical Center, New York, NY, United States
- Departments of Cell Biology, Psychiatry, New York University Langone Medical Center, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Langone Medical Center, New York, NY, United States
- Department of Otolaryngology, New York University Langone Medical Center, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
| | - Khalil Saadipour
- Departments of Cell Biology, Neuroscience & Physiology, and Psychiatry, Skirball Institute for Biomolecular Medicine, New York, NY, United States
| | - Kevin Williams
- Departments of Biology and Psychology, University of Georgia, Athens, GA, United States
| | - Latika Khatri
- Departments of Cell Biology, Neuroscience & Physiology, and Psychiatry, Skirball Institute for Biomolecular Medicine, New York, NY, United States
| | - Robert C. Froemke
- Departments of Cell Biology, Neuroscience & Physiology, and Psychiatry, Skirball Institute for Biomolecular Medicine, New York, NY, United States
- Neuroscience Institute, New York University Langone Medical Center, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Langone Medical Center, New York, NY, United States
- Department of Otolaryngology, New York University Langone Medical Center, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
| | - Moses V. Chao
- Departments of Cell Biology, Neuroscience & Physiology, and Psychiatry, Skirball Institute for Biomolecular Medicine, New York, NY, United States
- Neuroscience Institute, New York University Langone Medical Center, New York, NY, United States
- Departments of Cell Biology, Psychiatry, New York University Langone Medical Center, New York, NY, United States
- Department of Neuroscience and Physiology, New York University Langone Medical Center, New York, NY, United States
- Center for Neural Science, New York University, New York, NY, United States
- *Correspondence: Moses V. Chao
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9
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The Conflicting Role of Caffeine Supplementation on Hyperoxia-Induced Injury on the Cerebellar Granular Cell Neurogenesis of Newborn Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:5769784. [PMID: 35693697 PMCID: PMC9175096 DOI: 10.1155/2022/5769784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/04/2022] [Accepted: 04/28/2022] [Indexed: 11/28/2022]
Abstract
Preterm birth disrupts cerebellar development, which may be mediated by systemic oxidative stress that damages neuronal developmental stages. Impaired cerebellar neurogenesis affects several downstream targets important for cognition, emotion, and speech. In this study, we demonstrate that oxidative stress induced with high oxygen (80%) for three or five postnatal days (P3/P5) could significantly damage neurogenesis and proliferative capacity of granular cell precursor and Purkinje cells in rat pups. Reversal of cellular neuronal damage after recovery to room air (P15) was augmented by treatment with caffeine. However, downstream transcripts important for migration and differentiation of postmitotic granular cells were irreversibly reduced by hyperoxia, without rescue by caffeine. Protective effects of caffeine in the cerebellum were limited to neuronal survival but failed to restore important transcript signatures.
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10
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Chronic partial TrkB activation reduces seizures and mortality in a mouse model of Dravet syndrome. Proc Natl Acad Sci U S A 2022; 119:2022726119. [PMID: 35165147 PMCID: PMC8851461 DOI: 10.1073/pnas.2022726119] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2021] [Indexed: 12/03/2022] Open
Abstract
Dravet syndrome (DS) is a severe childhood epileptic encephalopathy characterized by intractable seizures and comorbidities, including a high rate of premature mortality. DS is mainly caused by loss-of-function mutations of the Scn1a gene encoding sodium channel Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, causing DS phenotypes. Effective pharmacological therapy targeting defective PV interneurons is currently not available. This study demonstrated that early treatment with a partial TrkB receptor agonist, LM22A-4, increased Nav1.1 expression, improved PV interneuron function, and reduced seizure occurrence and mortality rate in DS mice, suggesting a potential therapy for DS. Dravet syndrome (DS) is one of the most severe childhood epilepsies, characterized by intractable seizures and comorbidities including cognitive and social dysfunction and high premature mortality. DS is mainly caused by loss-of-function mutations in the Scn1a gene encoding Nav1.1 that is predominantly expressed in inhibitory parvalbumin-containing (PV) interneurons. Decreased Nav1.1 impairs PV cell function, contributing to DS phenotypes. Effective pharmacological therapy that targets defective PV interneurons is not available. The known role of brain-derived neurotrophic factor (BDNF) in the development and maintenance of interneurons, together with our previous results showing improved PV interneuronal function and antiepileptogenic effects of a TrkB receptor agonist in a posttraumatic epilepsy model, led to the hypothesis that early treatment with a TrkB receptor agonist might prevent or reduce seizure activity in DS mice. To test this hypothesis, we treated DS mice with LM22A-4 (LM), a partial agonist at the BDNF TrkB receptor, for 7 d starting at postnatal day 13 (P13), before the onset of spontaneous seizures. Results from immunohistochemistry, Western blot, whole-cell patch-clamp recording, and in vivo seizure monitoring showed that LM treatment increased the number of perisomatic PV interneuronal synapses around cortical pyramidal cells in layer V, upregulated Nav1.1 in PV neurons, increased inhibitory synaptic transmission, and decreased seizures and the mortality rate in DS mice. The results suggest that early treatment with a partial TrkB receptor agonist may be a promising therapeutic approach to enhance PV interneuron function and reduce epileptogenesis and premature death in DS.
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11
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Almacellas-Barbanoj A, Albini M, Satapathy A, Jaudon F, Michetti C, Krawczun-Rygmaczewska A, Huang H, Manago F, Papaleo F, Benfenati F, Cesca F. Kidins220/ARMS modulates brain morphology and anxiety-like traits in adult mice. Cell Death Dis 2022; 8:58. [PMID: 35140204 PMCID: PMC8828717 DOI: 10.1038/s41420-022-00854-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/12/2022] [Accepted: 01/25/2022] [Indexed: 11/17/2022]
Abstract
Kinase D interacting substrate of 220 kDa (Kidins220), also known as ankyrin repeat-rich membrane spanning (ARMS), is a transmembrane scaffold protein that participates in fundamental aspects of neuronal physiology including cell survival, differentiation, and synaptic plasticity. The Kidins220 constitutive knockout line displays developmental defects in the nervous and cardiovascular systems that lead to embryonic lethality, which has so far precluded the study of this protein in the adult. Moreover, Kidins220 mRNA is tightly regulated by alternative splicing, whose impact on nervous system physiology has not yet been addressed in vivo. Here, we have asked to what extent the absence of Kidins220 splicing and the selective knockout of Kidins220 impact on adult brain homeostasis. To answer this question, we used a floxed line that expresses only the full-length, non-spliced Kidins220 mRNA, and a forebrain-specific, CaMKII-Cre driven Kidins220 conditional knockout (cKO) line. Kidins220 cKO brains are characterized by enlarged ventricles in the absence of cell death, and by deficient dendritic arborization in several cortical regions. The deletion of Kidins220 leads to behavioral changes, such as reduced anxiety-like traits linked to alterations in TrkB-BDNF signaling and sex-dependent alterations of hippocampal-dependent spatial memory. Kidins220 floxed mice present similarly enlarged brain ventricles and increased associative memory. Thus, both the absolute levels of Kidins220 expression and its splicing pattern are required for the correct brain development and related expression of behavioral phenotypes. These findings are relevant in light of the increasing evidence linking mutations in the human KIDINS220 gene to the onset of severe neurodevelopmental disorders.
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Affiliation(s)
- Amanda Almacellas-Barbanoj
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,Clinical and Experimental Epilepsy, UCL Queen Square Institute of Neurology, London, UK
| | - Martina Albini
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,Department of Experimental Medicine, University of Genova, 16132, Genova, Italy
| | - Annyesha Satapathy
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Caterina Michetti
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,Department of Experimental Medicine, University of Genova, 16132, Genova, Italy
| | - Alicja Krawczun-Rygmaczewska
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,Department of Life Sciences, University of Trieste, 34127, Trieste, Italy
| | - Huiping Huang
- Genetics of Cognition Laboratory, Neuroscience area, Istituto Italiano di Tecnologia, via Morego, 30, 16163, Genova, Italy
| | - Francesca Manago
- Genetics of Cognition Laboratory, Neuroscience area, Istituto Italiano di Tecnologia, via Morego, 30, 16163, Genova, Italy
| | - Francesco Papaleo
- Genetics of Cognition Laboratory, Neuroscience area, Istituto Italiano di Tecnologia, via Morego, 30, 16163, Genova, Italy
| | - Fabio Benfenati
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy.,IRCCS Ospedale Policlinico San Martino, 16132, Genova, Italy
| | - Fabrizia Cesca
- Center for Synaptic Neuroscience and Technology, Fondazione Istituto Italiano di Tecnologia, 16132, Genova, Italy. .,Department of Life Sciences, University of Trieste, 34127, Trieste, Italy.
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12
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Pleiotropic effects of BDNF on the cerebellum and hippocampus: Implications for neurodevelopmental disorders. Neurobiol Dis 2022; 163:105606. [PMID: 34974125 DOI: 10.1016/j.nbd.2021.105606] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/22/2021] [Accepted: 12/29/2021] [Indexed: 12/17/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is one of the most studied neurotrophins in the mammalian brain, essential not only to the development of the central nervous system but also to synaptic plasticity. BDNF is present in various brain areas, but highest levels of expression are seen in the cerebellum and hippocampus. After birth, BDNF acts in the cerebellum as a mitogenic and chemotactic factor, stimulating the cerebellar granule cell precursors to proliferate, migrate and maturate, while in the hippocampus BDNF plays a fundamental role in synaptic transmission and plasticity, representing a key regulator for the long-term potentiation, learning and memory. Furthermore, the expression of BDNF is highly regulated and changes of its expression are associated with both physiological and pathological conditions. The purpose of this review is to provide an overview of the current state of knowledge on the BDNF biology and its neurotrophic role in the proper development and functioning of neurons and synapses in two important brain areas of postnatal neurogenesis, the cerebellum and hippocampus. Dysregulation of BDNF expression and signaling, resulting in alterations in neuronal maturation and plasticity in both systems, is a common hallmark of several neurodevelopmental diseases, such as autism spectrum disorder, suggesting that neuronal malfunction present in these disorders is the result of excessive or reduced of BDNF support. We believe that the more the relevance of the pathophysiological actions of BDNF, and its downstream signals, in early postnatal development will be highlighted, the more likely it is that new neuroprotective therapeutic strategies will be identified in the treatment of various neurodevelopmental disorders.
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13
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Postnatal Sox6 Regulates Synaptic Function of Cortical Parvalbumin-Expressing Neurons. J Neurosci 2021; 41:8876-8886. [PMID: 34503995 PMCID: PMC8549537 DOI: 10.1523/jneurosci.0021-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 08/12/2021] [Accepted: 08/16/2021] [Indexed: 11/29/2022] Open
Abstract
Cortical parvalbumin-expressing (Pvalb+) neurons provide robust inhibition to neighboring pyramidal neurons, crucial for the proper functioning of cortical networks. This class of inhibitory neurons undergoes extensive synaptic formation and maturation during the first weeks after birth and continue to dynamically maintain their synaptic output throughout adulthood. While several transcription factors, such as Nkx2-1, Lhx6, and Sox6, are known to be necessary for the differentiation of progenitors into Pvalb+ neurons, which transcriptional programs underlie the postnatal maturation and maintenance of Pvalb+ neurons' innervation and synaptic function remains largely unknown. Because Sox6 is continuously expressed in Pvalb+ neurons until adulthood, we used conditional knock-out strategies to investigate its putative role in the postnatal maturation and synaptic function of cortical Pvalb+ neurons in mice of both sexes. We found that early postnatal loss of Sox6 in Pvalb+ neurons leads to failure of synaptic bouton growth, whereas later removal in mature Pvalb+ neurons in the adult causes shrinkage of already established synaptic boutons. Paired recordings between Pvalb+ neurons and pyramidal neurons revealed reduced release probability and increased failure rate of Pvalb+ neurons' synaptic output. Furthermore, Pvalb+ neurons lacking Sox6 display reduced expression of full-length tropomyosin-receptor kinase B (TrkB), a key modulator of GABAergic transmission. Once re-expressed in neurons lacking Sox6, TrkB was sufficient to rescue the morphologic synaptic phenotype. Finally, we showed that Sox6 mRNA levels were increased by motor training. Our data thus suggest a constitutive role for Sox6 in the maintenance of synaptic output from Pvalb+ neurons into adulthood. SIGNIFICANCE STATEMENT Cortical parvalbumin-expressing (Pvalb+) inhibitory neurons provide robust inhibition to neighboring pyramidal neurons, crucial for the proper functioning of cortical networks. These inhibitory neurons undergo extensive synaptic formation and maturation during the first weeks after birth and continue to dynamically maintain their synaptic output throughout adulthood. However, it remains largely unknown which transcriptional programs underlie the postnatal maturation and maintenance of Pvalb+ neurons. Here, we show that the transcription factor Sox6 cell-autonomously regulates the synaptic maintenance and output of Pvalb+ neurons until adulthood, leaving unaffected other maturational features of this neuronal population.
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14
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Lau CG, Zhang H, Murthy VN. Deletion of TrkB in parvalbumin interneurons alters cortical neural dynamics. J Cell Physiol 2021; 237:949-964. [PMID: 34491578 PMCID: PMC8810709 DOI: 10.1002/jcp.30571] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/20/2021] [Accepted: 08/23/2021] [Indexed: 11/25/2022]
Abstract
Signaling by neurotrophins such as the brain‐derived neurotrophic factor (BDNF) is known to modulate development of interneurons, but the circuit effects of this modulation remain unclear. Here, we examined the impact of deleting TrkB, a BDNF receptor, in parvalbumin‐expressing (PV) interneurons on the balance of excitation and inhibition (E‐I) in cortical circuits. In the mouse olfactory cortex, TrkB deletion impairs multiple aspects of PV neuronal function including synaptic excitation, intrinsic excitability, and the innervation pattern of principal neurons. Impaired PV cell function resulted in aberrant spiking patterns in principal neurons in response to stimulation of sensory inputs. Surprisingly, dampened PV neuronal function leads to a paradoxical decrease in overall excitability in cortical circuits. Our study demonstrates that, by modulating PV circuit plasticity and development, TrkB plays a critical role in shaping the evoked pattern of activity in a cortical network.
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Affiliation(s)
- Chunyue Geoffrey Lau
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China.,Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
| | - Huiqi Zhang
- Department of Neuroscience, City University of Hong Kong, Hong Kong, China
| | - Venkatesh N Murthy
- Department of Molecular and Cellular Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA
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15
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Li X, Wang Q, Ding J, Wang S, Dong C, Wu Q. Exercise training modulates glutamic acid decarboxylase-65/67 expression through TrkB signaling to ameliorate neuropathic pain in rats with spinal cord injury. Mol Pain 2021; 16:1744806920924511. [PMID: 32418502 PMCID: PMC7235678 DOI: 10.1177/1744806920924511] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Neuropathic pain is one of the most frequently stated complications after spinal cord injury. In post-spinal cord injury, the decrease of gamma aminobutyric acid synthesis within the distal spinal cord is one of the main causes of neuropathic pain. The predominant research question of this study was whether exercise training may promote the expression of glutamic acid decarboxylase-65 and glutamic acid decarboxylase-67, which are key enzymes of gamma aminobutyric acid synthesis, within the distal spinal cord through tropomyosin-related kinase B signaling, as its synthesis assists to relieve neuropathic pain after spinal cord injury. Animal experiment was conducted, and all rats were allocated into five groups: Sham group, SCI/PBS group, SCI-TT/PBS group, SCI/tropomyosin-related kinase B-IgG group, and SCI-TT/tropomyosin-related kinase B-IgG group, and then T10 contusion SCI model was performed as well as the tropomyosin-related kinase B-IgG was used to block the tropomyosin-related kinase B activation. Mechanical withdrawal thresholds and thermal withdrawal latencies were used for assessing pain-related behaviors. Western blot analysis was used to detect the expression of brain-derived neurotrophic factor, tropomyosin-related kinase B, CREB, p-REB, glutamic acid decarboxylase-65, and glutamic acid decarboxylase-67 within the distal spinal cord. Immunohistochemistry was used to analyze the distribution of CREB, p-CREB, glutamic acid decarboxylase-65, and glutamic acid decarboxylase-67 within the distal spinal cord dorsal horn. The results showed that exercise training could significantly mitigate the mechanical allodynia and thermal hyperalgesia in post-spinal cord injury and increase the synthesis of brain-derived neurotrophic factor, tropomyosin-related kinase B, CREB, p-CREB, glutamic acid decarboxylase-65, and glutamic acid decarboxylase-67 within the distal spinal cord. After the tropomyosin-related kinase B signaling was blocked, the analgesic effect of exercise training was inhibited, and in the SCI-TT/tropomyosin-related kinase B-IgG group, the synthesis of CREB, p-CREB, glutamic acid decarboxylase-65, and glutamic acid decarboxylase-67 within the distal spinal cord were also significantly reduced compared with the SCI-TT/PBS group. This study shows that exercise training may increase the glutamic acid decarboxylase-65 and glutamic acid decarboxylase-67 expression within the spinal cord dorsal horn through the tropomyosin-related kinase B signaling, and this mechanism may play a vital role in relieving the neuropathic pain of rats caused by incomplete SCI.
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Affiliation(s)
- Xiangzhe Li
- Rehabilitation Medical Center, the Affiliated Suzhou Science & Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, People's Republic of China
| | - Qinghua Wang
- Laboratory Animal Center, Nantong University, Nantong, Jiangsu, People's Republic of China
| | - Jie Ding
- Departments of Respiratory Care, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China
| | - Sheng Wang
- Rehabilitation Medical Center, the Affiliated Suzhou Science & Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, People's Republic of China
| | - Chuanming Dong
- Department of Anatomy, Medical College of Nantong University, Nantong, Jiangsu, People's Republic of China
| | - Qinfeng Wu
- Rehabilitation Medical Center, the Affiliated Suzhou Science & Technology Town Hospital of Nanjing Medical University, Suzhou, Jiangsu, People's Republic of China
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16
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Sheeler C, Rosa JG, Borgenheimer E, Mellesmoen A, Rainwater O, Cvetanovic M. Post-symptomatic Delivery of Brain-Derived Neurotrophic Factor (BDNF) Ameliorates Spinocerebellar Ataxia Type 1 (SCA1) Pathogenesis. THE CEREBELLUM 2021; 20:420-429. [PMID: 33394333 DOI: 10.1007/s12311-020-01226-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 12/06/2020] [Indexed: 11/26/2022]
Abstract
Spinocerebellar ataxia type 1 (SCA1) is a fatal neurodegenerative disease caused by an abnormal expansion of CAG repeats in the Ataxin1 (ATXN1) gene. SCA1 is characterized by motor deficits, cerebellar neurodegeneration, and gliosis and gene expression changes. Expression of brain-derived neurotrophic factor (BDNF), growth factor important for the survival and function of cerebellar neurons, is decreased in ATXN1[82Q] mice, the Purkinje neuron specific transgenic mouse model of SCA1. As this decrease in BDNF expression may contribute to cerebellar neurodegeneration, we tested whether delivery of extrinsic human BDNF via osmotic ALZET pumps has a beneficial effect on disease severity in this mouse model of SCA1. Additionally, to test the effects of BDNF on established and progressing cerebellar pathogenesis and motor deficits, we delivered BDNF post-symptomatically. We have found that post-symptomatic delivery of extrinsic BDNF ameliorated motor deficits and cerebellar pathology (i.e., dendritic atrophy of Purkinje cells, and astrogliosis) indicating therapeutic potential of BDNF even after the onset of symptoms in SCA1. However, BDNF did not alter Purkinje cell gene expression changes indicating that certain aspects of disease pathogenesis cannot be ameliorated/slowed down with BDNF and that combinational therapies may be needed.
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Affiliation(s)
- Carrie Sheeler
- Department of Neuroscience, University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Juao-Guilherme Rosa
- Department of Neuroscience, University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Ella Borgenheimer
- Department of Neuroscience, University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Aaron Mellesmoen
- Department of Neuroscience, University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Orion Rainwater
- Department of Lab Medicine and Pathology, University of Minnesota, 420 Delaware Street SE, Minneapolis, 55455, USA
| | - Marija Cvetanovic
- Department of Neuroscience, University of Minnesota, 321 Church Street SE, Minneapolis, MN, 55455, USA.
- Institute for Translational Neuroscience, University of Minnesota, 2101 6th Street SE, Minneapolis, MN, 55455, USA.
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17
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Distinct Effects of BDNF and NT-3 on the Dendrites and Presynaptic Boutons of Developing Olfactory Bulb GABAergic Interneurons In Vitro. Cell Mol Neurobiol 2021; 42:1399-1417. [PMID: 33392918 DOI: 10.1007/s10571-020-01030-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 12/11/2020] [Indexed: 12/23/2022]
Abstract
Brain-derived neurotrophic factor (BDNF) and neurotrophin 3 (NT-3) are known to regulate neuronal morphology and the formation of neural circuits, yet the neuronal targets of each neurotrophin are still to be defined. To address how these neurotrophins regulate the morphological and synaptic differentiation of developing olfactory bulb (OB) GABAergic interneurons, we analyzed the effect of BDNF and NT-3 on GABA+-neurons and on different subtypes of these neurons: tyrosine hydroxylase (TH+); calretinin (Calr+); calbindin (Calb+); and parvalbumin (PVA+). These cells were generated from cultured embryonic mouse olfactory bulb neural stem cells (eOBNSCs) and after 14 days in vitro (DIV), when the neurons expressed TrkB and/or TrkC receptors, BDNF and NT-3 did not significantly change the number of neurons. However, long-term BDNF treatment did produce a longer total dendrite length and/or more dendritic branches in all the interneuron populations studied, except for PVA+-neurons. Similarly, BDNF caused an increase in the cell body perimeter in all the interneuron populations analyzed, except for PVA+-neurons. GABA+- and TH+-neurons were also studied at 21 DIV, when BDNF produced significantly longer neurites with no clear change in their number. Notably, these neurons developed synaptophysin+ boutons at 21 DIV, the size of which augmented significantly following exposure to either BDNF or NT-3. Our results show that in conditions that maintain neuronal survival, BDNF but not NT-3 promotes the morphological differentiation of developing OB interneurons in a cell-type-specific manner. In addition, our findings suggest that BDNF and NT-3 may promote synapse maturation by enhancing the size of synaptic boutons.
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18
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Adams I, Yang T, Longo FM, Katz DM. Restoration of motor learning in a mouse model of Rett syndrome following long-term treatment with a novel small-molecule activator of TrkB. Dis Model Mech 2020; 13:13/11/dmm044685. [PMID: 33361117 PMCID: PMC7710018 DOI: 10.1242/dmm.044685] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 09/23/2020] [Indexed: 12/23/2022] Open
Abstract
Reduced expression of brain-derived neurotrophic factor (BDNF) and impaired activation of the BDNF receptor, tropomyosin receptor kinase B (TrkB; also known as Ntrk2), are thought to contribute significantly to the pathophysiology of Rett syndrome (RTT), a severe neurodevelopmental disorder caused by loss-of-function mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MeCP2). Previous studies from this and other laboratories have shown that enhancing BDNF expression and/or TrkB activation in Mecp2-deficient mouse models of RTT can ameliorate or reverse abnormal neurological phenotypes that mimic human RTT symptoms. The present study reports on the preclinical efficacy of a novel, small-molecule, non-peptide TrkB partial agonist, PTX-BD4-3, in heterozygous female Mecp2 mutant mice, a well-established RTT model that recapitulates the genetic mosaicism of the human disease. PTX-BD4-3 exhibited specificity for TrkB in cell-based assays of neurotrophin receptor activation and neuronal cell survival and in in vitro receptor binding assays. PTX-BD4-3 also activated TrkB following systemic administration to wild-type and Mecp2 mutant mice and was rapidly cleared from the brain and plasma with a half-life of ∼2 h. Chronic intermittent treatment of Mecp2 mutants with a low dose of PTX-BD4-3 (5 mg/kg, intraperitoneally, once every 3 days for 8 weeks) reversed deficits in two core RTT symptom domains – respiration and motor control – and symptom rescue was maintained for at least 24 h after the last dose. Together, these data indicate that significant clinically relevant benefit can be achieved in a mouse model of RTT with a chronic intermittent, low-dose treatment paradigm targeting the neurotrophin receptor TrkB. Editor's choice: Long-term intermittent treatment with a newly developed partial agonist of the TrkB neurotrophin receptor reverses deficits in motor learning and respiration in a mouse model of Rett syndrome.
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Affiliation(s)
- Ian Adams
- Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106-4975, USA
| | - Tao Yang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - David M Katz
- Department of Neurosciences, Case Western Reserve University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106-4975, USA
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19
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Hill RA, Grech AM, Notaras MJ, Sepulveda M, van den Buuse M. Brain-Derived Neurotrophic Factor Val66Met polymorphism interacts with adolescent stress to alter hippocampal interneuron density and dendritic morphology in mice. Neurobiol Stress 2020; 13:100253. [PMID: 33344708 PMCID: PMC7739172 DOI: 10.1016/j.ynstr.2020.100253] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 09/03/2020] [Accepted: 09/26/2020] [Indexed: 01/06/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) plays essential roles in GABAergic interneuron development. The common BDNF val66met polymorphism, leads to decreased activity-dependent release of BDNF. The current study used a humanized mouse model of the BDNF val66met polymorphism to determine how reduced activity-dependent release of BDNF, both on its own, and in combination with chronic adolescent stress hormone, impact hippocampal GABAergic interneuron cell density and dendrite morphology. Male and female Val/Val and Met/Met mice were exposed to corticosterone (CORT) or placebo in their drinking water from weeks 6-8, before brains were perfuse-fixed at 15 weeks. Cell density and dendrite morphology of immunofluorescent labelled inhibitory interneurons; somatostatin, parvalbumin and calretinin in the CA1, and 3 and dentate gyrus (DG) across the dorsal (DHP) and ventral hippocampus (VHP) were assessed by confocal z-stack imaging, and IMARIS dendritic mapping software. Mice with the Met/Met genotype showed significantly lower somatostatin cell density compared to Val/Val controls in the DHP, and altered somatostatin interneuron dendrite morphology including branch depth, and spine density. Parvalbumin-positive interneurons were unchanged between genotype groups, however BDNF val66met genotype influenced the dendritic volume, branch level and spine density of parvalbumin interneurons differentially across hippocampal subregions. Contrary to this, no such effects were observed for calretinin-positive interneurons. Adolescent exposure to CORT treatment also significantly altered somatostatin and parvalbumin dendrite branch level and the combined effect of Met/Met genotype and CORT treatment significantly reduced somatostatin and parvalbumin dendrite spine density. In sum, the BDNFVal66Met polymorphism significantly alters somatostatin and parvalbumin-positive interneuron cell development and dendrite morphology. Additionally, we also report a compounding effect of the Met/Met genotype and chronic adolescent CORT treatment on dendrite spine density, indicating that adolescence is a sensitive period of risk for Val66Met polymorphism carriers.
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Affiliation(s)
- Rachel Anne Hill
- Department of Psychiatry, School of Clinical Sciences, Monash University, Monash Medical Centre, Clayton, VIC, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
- Corresponding author. Department of Psychiatry, School of Clinical Sciences at Monash Health, Monash University Level 3, Monash Medical Centre 27Wright St Clayton VIC 3168 Australia, .
| | - Adrienne Mary Grech
- Department of Psychiatry, School of Clinical Sciences, Monash University, Monash Medical Centre, Clayton, VIC, Australia
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Michael J. Notaras
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
- Weill Cornell Medical College of Cornell University, Centre for Neurogenetics, Brain & Mind Research Institute, New York City, New York, USA
| | - Mauricio Sepulveda
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
| | - Maarten van den Buuse
- School of Psychology and Public Health, La Trobe University, Melbourne, VIC, Australia
- Department of Pharmacology, University of Melbourne, VIC, Australia
- The College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia
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20
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Kobrina A, Schrode KM, Screven LA, Javaid H, Weinberg MM, Brown G, Board R, Villavisanis DF, Dent ML, Lauer AM. Linking anatomical and physiological markers of auditory system degeneration with behavioral hearing assessments in a mouse (Mus musculus) model of age-related hearing loss. Neurobiol Aging 2020; 96:87-103. [PMID: 32950782 DOI: 10.1016/j.neurobiolaging.2020.08.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 08/03/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022]
Abstract
Age-related hearing loss is a very common sensory disability, affecting one in three older adults. Establishing a link between anatomical, physiological, and behavioral markers of presbycusis in a mouse model can improve the understanding of this disorder in humans. We measured age-related hearing loss for a variety of acoustic signals in quiet and noisy environments using an operant conditioning procedure and investigated the status of peripheral structures in CBA/CaJ mice. Mice showed the greatest degree of hearing loss in the last third of their lifespan, with higher thresholds in noisy than in quiet conditions. Changes in auditory brainstem response thresholds and waveform morphology preceded behavioral hearing loss onset. Loss of hair cells, auditory nerve fibers, and signs of stria vascularis degeneration were observed in old mice. The present work underscores the difficulty in ascribing the primary cause of age-related hearing loss to any particular type of cellular degeneration. Revealing these complex structure-function relationships is critical for establishing successful intervention strategies to restore hearing or prevent presbycusis.
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Affiliation(s)
| | - Katrina M Schrode
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Laurel A Screven
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Hamad Javaid
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Madison M Weinberg
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Garrett Brown
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Ryleigh Board
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Dillan F Villavisanis
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA
| | - Micheal L Dent
- Department of Psychology, University at Buffalo SUNY, Buffalo, NY, USA
| | - Amanda M Lauer
- Department of Otolaryngology-Head and Neck Surgery and Center for Hearing and Balance, Johns Hopkins University, Baltimore, MD, USA.
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21
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Refinement of Cerebellar Network Organization by Extracellular Signaling During Development. Neuroscience 2020; 462:44-55. [PMID: 32502568 DOI: 10.1016/j.neuroscience.2020.05.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022]
Abstract
The cerebellum forms regular neural network structures consisting of a few major types of neurons, such as Purkinje cells, granule cells, and molecular layer interneurons, and receives two major inputs from climbing fibers and mossy fibers. Its regular structures consist of three well-defined layers, with each type of neuron designated to a specific location and forming specific synaptic connections. During the first few weeks of postnatal development in rodents, the cerebellum goes through dynamic changes via proliferation, migration, differentiation, synaptogenesis, and maturation, to create such a network structure. The development of this organized network structure presumably relies on the communication between developing elements in the network, including not only individual neurons, but also their dendrites, axons, and synapses. Therefore, it is reasonable that extracellular signaling via synaptic transmission, secreted molecules, and cell adhesion molecules, plays important roles in cerebellar network development. Although it is not yet clear as to how overall cerebellar development is orchestrated, there is indeed accumulating lines of evidence that extracellular signaling acts toward the development of individual elements in the cerebellar networks. In this article, we introduce what we have learned from many studies regarding the extracellular signaling required for cerebellar network development, including our recent study suggesting the importance of unbiased synaptic inputs from parallel fibers.
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22
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Sathyanesan A, Zhou J, Scafidi J, Heck DH, Sillitoe RV, Gallo V. Emerging connections between cerebellar development, behaviour and complex brain disorders. Nat Rev Neurosci 2019; 20:298-313. [PMID: 30923348 DOI: 10.1038/s41583-019-0152-2] [Citation(s) in RCA: 150] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The human cerebellum has a protracted developmental timeline compared with the neocortex, expanding the window of vulnerability to neurological disorders. As the cerebellum is critical for motor behaviour, it is not surprising that most neurodevelopmental disorders share motor deficits as a common sequela. However, evidence gathered since the late 1980s suggests that the cerebellum is involved in motor and non-motor function, including cognition and emotion. More recently, evidence indicates that major neurodevelopmental disorders such as intellectual disability, autism spectrum disorder, attention-deficit hyperactivity disorder and Down syndrome have potential links to abnormal cerebellar development. Out of recent findings from clinical and preclinical studies, the concept of the 'cerebellar connectome' has emerged that can be used as a framework to link the role of cerebellar development to human behaviour, disease states and the design of better therapeutic strategies.
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Affiliation(s)
- Aaron Sathyanesan
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.
| | - Joy Zhou
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA
| | - Joseph Scafidi
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA.,George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - Detlef H Heck
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Roy V Sillitoe
- Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, USA.,Department of Neuroscience, Baylor College of Medicine, Houston, TX, USA.,Program in Developmental Biology, Baylor College of Medicine, Houston, TX, USA
| | - Vittorio Gallo
- Center for Neuroscience Research, Children's Research Institute, Children's National Health System, Washington, DC, USA. .,George Washington University School of Medicine and Health Sciences, Washington, DC, USA.
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23
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Sex-specific spatial memory deficits in mice with a conditional TrkB deletion on parvalbumin interneurons. Behav Brain Res 2019; 372:111984. [DOI: 10.1016/j.bbr.2019.111984] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 05/23/2019] [Accepted: 05/27/2019] [Indexed: 12/12/2022]
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24
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Sudarshan K, Boda AK, Dogra S, Bose I, Yadav PN, Aidhen IS. Discovery of an isocoumarin analogue that modulates neuronal functions via neurotrophin receptor TrkB. Bioorg Med Chem Lett 2019; 29:585-590. [PMID: 30600206 DOI: 10.1016/j.bmcl.2018.12.057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 12/22/2018] [Accepted: 12/25/2018] [Indexed: 01/07/2023]
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25
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Abe Y, Honsho M, Itoh R, Kawaguchi R, Fujitani M, Fujiwara K, Hirokane M, Matsuzaki T, Nakayama K, Ohgi R, Marutani T, Nakayama KI, Yamashita T, Fujiki Y. Peroxisome biogenesis deficiency attenuates the BDNF-TrkB pathway-mediated development of the cerebellum. Life Sci Alliance 2018; 1:e201800062. [PMID: 30519675 PMCID: PMC6277683 DOI: 10.26508/lsa.201800062] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 11/08/2018] [Accepted: 11/08/2018] [Indexed: 01/22/2023] Open
Abstract
Peroxisome biogenesis disorders (PBDs) manifest as neurological deficits in the central nervous system, including neuronal migration defects and abnormal cerebellum development. However, the mechanisms underlying pathogenesis remain enigmatic. Here, to investigate how peroxisome deficiency causes neurological defects of PBDs, we established a new PBD model mouse defective in peroxisome assembly factor Pex14p, termed Pex14 ΔC/ΔC mouse. Pex14 ΔC/ΔC mouse manifests a severe symptom such as disorganization of cortical laminar structure and dies shortly after birth, although peroxisomal biogenesis and metabolism are partially defective. The Pex14 ΔC/ΔC mouse also shows malformation of the cerebellum including the impaired dendritic development of Purkinje cells. Moreover, extracellular signal-regulated kinase and AKT signaling are attenuated in this mutant mouse by an elevated level of brain-derived neurotrophic factor (BDNF) together with the enhanced expression of TrkB-T1, a dominant-negative isoform of the BDNF receptor. Our results suggest that dysregulation of the BDNF-TrkB pathway, an essential signaling for cerebellar morphogenesis, gives rise to the pathogenesis of the cerebellum in PBDs.
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Affiliation(s)
- Yuichi Abe
- Division of Organelle Homeostasis, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Masanori Honsho
- Division of Organelle Homeostasis, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Ryota Itoh
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Ryoko Kawaguchi
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Masashi Fujitani
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Kazushirou Fujiwara
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Masaaki Hirokane
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Takashi Matsuzaki
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Keiko Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.,Division of Cell Proliferation, Tohoku University Graduate School of Medicine, Sendai, Japan
| | - Ryohei Ohgi
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Toshihiro Marutani
- Graduate School of Systems Life Sciences and Department of Biology, Faculty of Sciences, Kyushu University Graduate School, Fukuoka, Japan
| | - Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Toshihide Yamashita
- Department of Molecular Neuroscience, Graduate School of Medicine, Osaka University, Osaka, Japan.,Core Research for Evolutional Science and Technology, Japan Science and Technology Agency, Tokyo, Japan
| | - Yukio Fujiki
- Division of Organelle Homeostasis, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
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26
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Chong PN, Sangu M, Huat TJ, Reza F, Begum T, Yusoff AAM, Jaafar H, Abdullah JM. Trkb-IP3 Pathway Mediating Neuroprotection in Rat Hippocampal Neuronal Cell Culture Following Induction of Kainic Acid. Malays J Med Sci 2018; 25:28-45. [PMID: 30914877 PMCID: PMC6422567 DOI: 10.21315/mjms2018.25.6.4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 10/17/2018] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Following brain injury, development of hippocampal sclerosis often led to the temporal lobe epilepsy which is sometimes resistant to common anti-epileptic drugs. Cellular and molecular changes underlying epileptogenesis in animal models were studied, however, the underlying mechanisms of kainic acid (KA) mediated neuronal damage in rat hippocampal neuron cell culture alone has not been elucidated yet. METHODS Embryonic day 18 (E-18) rat hippocampus neurons were cultured with poly-L-lysine coated glass coverslips. Following optimisation, KA (0.5 μM), a chemoconvulsant agent, was administered at three different time-points (30, 60 and 90 min) to induce seizure in rat hippocampal neuronal cell culture. We examined cell viability, neurite outgrowth density and immunoreactivity of the hippocampus neuron culture by measuring brain derived neurotrophic factor (BDNF), γ-amino butyric acid A (GABAA) subunit α-1 (GABRA1), tyrosine receptor kinase B (TrkB), and inositol trisphosphate receptor (IP3R/IP3) levels. RESULTS The results revealed significantly decreased and increased immunoreactivity changes in TrkB (a BDNF receptor) and IP3R, respectively, at 60 min time point. CONCLUSION The current findings suggest that TrkB and IP3 could have a neuroprotective role which could be a potential pharmacological target for anti-epilepsy drugs.
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Affiliation(s)
- Pei Nei Chong
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Muthuraju Sangu
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Tee Jong Huat
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Faruque Reza
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Tahamina Begum
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Abdul Aziz Mohamed Yusoff
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Hasnan Jaafar
- Department of Pathology, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
| | - Jafri Malin Abdullah
- Department of Neurosciences, School of Medical Sciences, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
- Centre for Neuroscience Services and Research, Universiti Sains Malaysia, 16150 Kubang Kerian, Kelantan, Malaysia
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27
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Central Compensation in Auditory Brainstem after Damaging Noise Exposure. eNeuro 2018; 5:eN-CFN-0250-18. [PMID: 30123822 PMCID: PMC6096756 DOI: 10.1523/eneuro.0250-18.2018] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 07/19/2018] [Indexed: 12/15/2022] Open
Abstract
Noise exposure is one of the most common causes of hearing loss and peripheral damage to the auditory system. A growing literature suggests that the auditory system can compensate for peripheral loss through increased central neural activity. The current study sought to investigate the link between noise exposure, increases in central gain, synaptic reorganization, and auditory function. All axons of the auditory nerve project to the cochlear nucleus, making it a requisite nucleus for sound detection. As the first synapse in the central auditory system, the cochlear nucleus is well positioned to respond plastically to loss of peripheral input. To investigate noise-induced compensation in the central auditory system, we measured auditory brainstem responses (ABRs) and auditory perception and collected tissue from mice exposed to broadband noise. Noise-exposed mice showed elevated ABR thresholds, reduced ABR wave 1 amplitudes, and spiral ganglion neuron loss. Despite peripheral damage, noise-exposed mice were hyperreactive to loud sounds and showed nearly normal behavioral sound detection thresholds. Ratios of late ABR peaks (2–4) relative to the first ABR peak indicated that brainstem pathways were hyperactive in noise-exposed mice, while anatomical analysis indicated there was an imbalance between expression of excitatory and inhibitory proteins in the ventral cochlear nucleus. The results of the current study suggest that a reorganization of excitation and inhibition in the ventral cochlear nucleus may drive hyperactivity in the central auditory system. This increase in central gain can compensate for peripheral loss to restore some aspects of auditory function.
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28
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Balkaya M, Cho S. Genetics of stroke recovery: BDNF val66met polymorphism in stroke recovery and its interaction with aging. Neurobiol Dis 2018; 126:36-46. [PMID: 30118755 DOI: 10.1016/j.nbd.2018.08.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 07/24/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022] Open
Abstract
Stroke leads to long term sensory, motor and cognitive impairments. Most patients experience some degree of spontaneous recovery which is mostly incomplete and varying greatly among individuals. The variation in recovery outcomes has been attributed to numerous factors including lesion size, corticospinal tract integrity, age, gender and race. It is well accepted that genetics play a crucial role in stroke incidence and accumulating evidence suggests that it is also a significant determinant in recovery. Among the number of genes and variations implicated in stroke recovery the val66met single nucleotide polymorphism (SNP) in the BDNF gene influences post-stroke plasticity in the most significant ways. Val66met is the most well characterized BDNF SNP and is common (40-50 % in Asian and 25-32% in Caucasian populations) in humans. It reduces activity-dependent BDNF release, dampens cortical plasticity and is implicated in numerous diseases. Earlier studies on the effects of val66met on stroke outcome and recovery presented primarily a maladaptive role. Novel findings however indicate a much more intricate interaction between val66met and stroke recovery which appears to be influenced by lesion location, post-stroke stage and age. This review will focus on the role of BDNF and val66met SNP in relation to stroke recovery and try to identify potential pathophysiologic mechanisms involved. The effects of age on val66met associated alterations in plasticity and potential consequences in terms of stroke are also discussed.
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Affiliation(s)
- Mustafa Balkaya
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Ave, White Plains, NY 10605, USA; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine at Burke Medical Research Institute, 785 Mamaroneck Ave, White Plains, NY 10605, USA
| | - Sunghee Cho
- Burke-Cornell Medical Research Institute, 785 Mamaroneck Ave, White Plains, NY 10605, USA; Feil Family Brain and Mind Research Institute, Weill Cornell Medicine at Burke Medical Research Institute, 785 Mamaroneck Ave, White Plains, NY 10605, USA.
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29
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Nakayama H, Abe M, Morimoto C, Iida T, Okabe S, Sakimura K, Hashimoto K. Microglia permit climbing fiber elimination by promoting GABAergic inhibition in the developing cerebellum. Nat Commun 2018; 9:2830. [PMID: 30026565 PMCID: PMC6053401 DOI: 10.1038/s41467-018-05100-z] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/23/2018] [Indexed: 01/01/2023] Open
Abstract
Circuit refinement during postnatal development is finely regulated by neuron–neuron interactions. Recent studies suggest participation of microglia in this process but it is unclear how microglia cooperatively act with neuronal mechanisms. To examine roles of microglia, we ablate microglia by microglia-selective deletion of colony-stimulating factor 1 receptor (Csf1r) by crossing floxed-Csf1r and Iba1-iCre mice (Csf1r-cKO). In Csf1r-cKO mice, refinement of climbing fiber (CF) to Purkinje cell (PC) innervation after postnatal day 10 (P10)–P12 is severely impaired. However, there is no clear morphological evidence suggesting massive engulfment of CFs by microglia. In Csf1r-cKO mice, inhibitory synaptic transmission is impaired and CF elimination is restored by diazepam, which suggests that impairment of CF elimination is caused by a defect of GABAergic inhibition on PCs, a prerequisite for CF elimination. These results indicate that microglia primarily promote GABAergic inhibition and secondarily facilitate the mechanism for CF elimination inherent in PCs. In the mammalian cerebellum, surplus synapses between climbing fibers (CF) and Purkinje cells (PC) are developmentally pruned. Here, Nakayama and colleagues show that ablation of microglia impairs pruning of CF-PC synapses because of dysfunction of GABAergic inhibition prerequisite for pruning.
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Affiliation(s)
- Hisako Nakayama
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.,Department of Physiology, School of Medicine, Tokyo Women's Medical University, 8-1 Kawada-cho, Sinjuku-ku, Tokyo, 162-8666, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan.,Department of Animal Model Development, Brain Research Institute, Niigata University, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan
| | - Chie Morimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.,Department of Psychosocial Rehabilitation Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan
| | - Tadatsune Iida
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan.,Department of Animal Model Development, Brain Research Institute, Niigata University, 1-757 Asahimachi-dori, Chuo-ku, Niigata, 951-8585, Japan
| | - Kouichi Hashimoto
- Department of Neurophysiology, Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8551, Japan.
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30
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Lorenz-Guertin JM, Jacob TC. GABA type a receptor trafficking and the architecture of synaptic inhibition. Dev Neurobiol 2018; 78:238-270. [PMID: 28901728 PMCID: PMC6589839 DOI: 10.1002/dneu.22536] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/08/2017] [Accepted: 09/08/2017] [Indexed: 12/21/2022]
Abstract
Ubiquitous expression of GABA type A receptors (GABAA R) in the central nervous system establishes their central role in coordinating most aspects of neural function and development. Dysregulation of GABAergic neurotransmission manifests in a number of human health disorders and conditions that in certain cases can be alleviated by drugs targeting these receptors. Precise changes in the quantity or activity of GABAA Rs localized at the cell surface and at GABAergic postsynaptic sites directly impact the strength of inhibition. The molecular mechanisms constituting receptor trafficking to and from these compartments therefore dictate the efficacy of GABAA R function. Here we review the current understanding of how GABAA Rs traffic through biogenesis, plasma membrane transport, and degradation. Emphasis is placed on discussing novel GABAergic synaptic proteins, receptor and scaffolding post-translational modifications, activity-dependent changes in GABAA R confinement, and neuropeptide and neurosteroid mediated changes. We further highlight modern techniques currently advancing the knowledge of GABAA R trafficking and clinically relevant neurodevelopmental diseases connected to GABAergic dysfunction. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 238-270, 2018.
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Affiliation(s)
- Joshua M Lorenz-Guertin
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15261
| | - Tija C Jacob
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, 15261
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31
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Gu F, Parada I, Yang T, Longo FM, Prince DA. Partial TrkB receptor activation suppresses cortical epileptogenesis through actions on parvalbumin interneurons. Neurobiol Dis 2018; 113:45-58. [PMID: 29408225 DOI: 10.1016/j.nbd.2018.01.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 01/21/2018] [Accepted: 01/24/2018] [Indexed: 01/17/2023] Open
Abstract
Post-traumatic epilepsy is one of the most common and difficult to treat forms of acquired epilepsy worldwide. Currently, there is no effective way to prevent post-traumatic epileptogenesis. It is known that abnormalities of interneurons, particularly parvalbumin-containing interneurons, play a critical role in epileptogenesis following traumatic brain injury. Thus, enhancing the function of existing parvalbumin interneurons might provide a logical therapeutic approach to prevention of post-traumatic epilepsy. The known positive effects of brain-derived neurotrophic factor on interneuronal growth and function through activation of its receptor tropomyosin receptor kinase B, and its decrease after traumatic brain injury, led us to hypothesize that enhancing trophic support might improve parvalbumin interneuronal function and decrease epileptogenesis. To test this hypothesis, we used the partial neocortical isolation ('undercut', UC) model of posttraumatic epileptogenesis in mature rats that were treated for 2 weeks, beginning on the day of injury, with LM22A-4, a newly designed partial agonist at the tropomyosin receptor kinase B. Effects of treatment were assessed with Western blots to measure pAKT/AKT; immunocytochemistry and whole cell patch clamp recordings to examine functional and structural properties of GABAergic interneurons; field potential recordings of epileptiform discharges in vitro; and video-EEG recordings of PTZ-induced seizures in vivo. Results showed that LM22A-4 treatment 1) increased pyramidal cell perisomatic immunoreactivity for VGAT, GAD65 and parvalbumin; 2) increased the density of close appositions of VGAT/gephyrin immunoreactive puncta (putative inhibitory synapses) on pyramidal cell somata; 3) increased the frequency of mIPSCs in pyramidal cells; and 4) decreased the incidence of spontaneous and evoked epileptiform discharges in vitro. 5) Treatment of rats with PTX BD4-3, another partial TrkB receptor agonist, reduced the incidence of bicuculline-induced ictal episodes in vitro and PTZ induced electrographic and behavioral ictal episodes in vivo. 6) Inactivation of TrkB receptors in undercut TrkBF616A mice with 1NMPP1 abolished both LM22A-4-induced effects on mIPSCs and on increased perisomatic VGAT-IR. Results indicate that chronic activation of the tropomyosin receptor kinase B by a partial agonist after cortical injury can enhance structural and functional measures of GABAergic inhibition and suppress posttraumatic epileptogenesis. Although the full agonist effects of brain-derived neurotrophic factor and tropomyosin receptor kinase B activation in epilepsy models have been controversial, the present results indicate that such trophic activation by a partial agonist may potentially serve as an effective therapeutic option for prophylactic treatment of posttraumatic epileptogenesis, and treatment of other neurological and psychiatric disorders whose pathogenesis involves impaired parvalbumin interneuronal function.
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Affiliation(s)
- Feng Gu
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, United States
| | - Isabel Parada
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, United States
| | - Tao Yang
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, United States
| | - Frank M Longo
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, United States
| | - David A Prince
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, United States.
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32
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Dan Q, Li T, Liu F. Hyperbaric oxygen therapy promotes the improvement of neurological recovery in rats with traumatic brain injury associated with TrkB activation. IBRAIN 2018. [DOI: 10.1002/j.2769-2795.2018.tb00029.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- Qi‐Qin Dan
- Department of AnesthesiologyInstitute of Neurological Disease Translational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanPeople's Republic of China
| | - Ting‐Ting Li
- Department of AnesthesiologyInstitute of Neurological Disease Translational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanPeople's Republic of China
| | - Fei Liu
- Department of AnesthesiologyInstitute of Neurological Disease Translational Neuroscience Center, West China Hospital, Sichuan UniversityChengduSichuanPeople's Republic of China
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33
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Pathobiological expression of the brain-derived neurotrophic factor (BDNF) in cerebellar cortex of sudden fetal and infant death victims. Int J Dev Neurosci 2017; 66:9-17. [PMID: 29174061 DOI: 10.1016/j.ijdevneu.2017.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/28/2017] [Accepted: 11/16/2017] [Indexed: 02/05/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF), a neurotrophin of the central nervous system, is able to regulate neuronal differentiation and modulate synaptic plasticity, being particularly involved in the development of the cerebellar cortical structure. The main aim of this study was to delineate, by immunohistochemistry, the BDNF expression in human cerebellar cortex of victims of fetal and infant death. The study was performed on a total of 45 cases, aged between 25 gestational weeks and 6 postnatal months, including 29 victims of sudden fetal and infant death and 16 age-matched subjects who died of known causes (Controls). We observed, in sudden death groups compared with Controls, a significantly higher incidence of defective BDNF expression in granule layers of the cerebellar cortex, which was particularly evident in the posterior lobule, a region that participates in respiratory control. These results were related to maternal smoking, allowing to speculate that nicotine, in addition to the well-known damages, can exert adverse effects during cerebellar cortex development, in particular in hindering the BDNF expression in the posterior lobule. This implies modifications of synaptic transmission in the respiratory circuits, with obvious deleterious consequences on survival.
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34
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Abstract
Research in the last two decades has identified many synaptic organizers in the central nervous system that directly regulate the assembly of pre- and/or postsynaptic molecules, such as synaptic vesicles, active zone proteins, and neurotransmitter receptors. They are classified into secreted factors and cell adhesion molecules, such as neurexins and neuroligins. Certain secreted factors are termed extracellular scaffolding proteins (ESPs) because they are components of the synaptic extracellular matrix and serve as a scaffold at the synaptic cleft. These include Lgi1, Cbln1, neuronal pentraxins, Hevin, thrombospondins, and glypicans. Diffusible secreted factors, such as Wnts, fibroblast growth factors, and semaphorins, tend to act from a distance. In contrast, ESPs remain at the synaptic cleft and often help synaptic adhesion and/or accumulation of postsynaptic receptors. Many fundamental questions remain about when, how, and why various synaptic organizers establish and modify the vast numbers of connections during development and throughout life.
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Affiliation(s)
- Michisuke Yuzaki
- Department of Physiology, Keio University School of Medicine, Tokyo 160-8582, Japan;
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35
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Hoxha E, Lippiello P, Scelfo B, Tempia F, Ghirardi M, Miniaci MC. Maturation, Refinement, and Serotonergic Modulation of Cerebellar Cortical Circuits in Normal Development and in Murine Models of Autism. Neural Plast 2017; 2017:6595740. [PMID: 28894610 PMCID: PMC5574313 DOI: 10.1155/2017/6595740] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/06/2017] [Accepted: 07/25/2017] [Indexed: 12/13/2022] Open
Abstract
The formation of the complex cerebellar cortical circuits follows different phases, with initial synaptogenesis and subsequent processes of refinement guided by a variety of mechanisms. The regularity of the cellular and synaptic organization of the cerebellar cortex allowed detailed studies of the structural plasticity mechanisms underlying the formation of new synapses and retraction of redundant ones. For the attainment of the monoinnervation of the Purkinje cell by a single climbing fiber, several signals are involved, including electrical activity, contact signals, homosynaptic and heterosynaptic interaction, calcium transients, postsynaptic receptors, and transduction pathways. An important role in this developmental program is played by serotonergic projections that, acting on temporally and spatially regulated postsynaptic receptors, induce and modulate the phases of synaptic formation and maturation. In the adult cerebellar cortex, many developmental mechanisms persist but play different roles, such as supporting synaptic plasticity during learning and formation of cerebellar memory traces. A dysfunction at any stage of this process can lead to disorders of cerebellar origin, which include autism spectrum disorders but are not limited to motor deficits. Recent evidence in animal models links impairment of Purkinje cell function with autism-like symptoms including sociability deficits, stereotyped movements, and interspecific communication by vocalization.
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Affiliation(s)
- Eriola Hoxha
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Torino, Italy
- Department of Neuroscience, University of Torino, Torino, Italy
| | | | - Bibiana Scelfo
- Department of Neuroscience, University of Torino, Torino, Italy
| | - Filippo Tempia
- Neuroscience Institute Cavalieri Ottolenghi (NICO), Torino, Italy
- Department of Neuroscience, University of Torino, Torino, Italy
- National Institute of Neuroscience (INN), Torino, Italy
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36
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Choo M, Miyazaki T, Yamazaki M, Kawamura M, Nakazawa T, Zhang J, Tanimura A, Uesaka N, Watanabe M, Sakimura K, Kano M. Retrograde BDNF to TrkB signaling promotes synapse elimination in the developing cerebellum. Nat Commun 2017; 8:195. [PMID: 28775326 PMCID: PMC5543168 DOI: 10.1038/s41467-017-00260-w] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Accepted: 06/14/2017] [Indexed: 12/31/2022] Open
Abstract
Elimination of early-formed redundant synapses during postnatal development is essential for functional neural circuit formation. Purkinje cells (PCs) in the neonatal cerebellum are innervated by multiple climbing fibers (CFs). A single CF is strengthened whereas the other CFs are eliminated in each PC dependent on postsynaptic activity in PC, but the underlying mechanisms are largely unknown. Here, we report that brain-derived neurotrophic factor (BDNF) from PC facilitates CF synapse elimination. By PC-specific deletion of BDNF combined with knockdown of BDNF receptors in CF, we show that BDNF acts retrogradely on TrkB in CFs, and facilitates elimination of CF synapses from PC somata during the third postnatal week. We also show that BDNF shares signaling pathway with metabotropic glutamate receptor 1, a key molecule that triggers a canonical pathway for CF synapse elimination. These results indicate that unlike other synapses, BDNF mediates punishment signal for synapse elimination in the developing cerebellum. During development, synapses are selectively strengthened or eliminated by activity-dependent competition. Here, the authors show that BDNF-TrkB retrograde signaling is a “punishment” signal that leads to elimination of climbing fiber-onto-Purkinje cell synapses in the developing cerebellum.
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Affiliation(s)
- Myeongjeong Choo
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Taisuke Miyazaki
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Meiko Kawamura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Takanobu Nakazawa
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Jianling Zhang
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Asami Tanimura
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Naofumi Uesaka
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, 060-8638, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata, 951-8585, Japan
| | - Masanobu Kano
- Department of Neurophysiology, Graduate School of Medicine, The University of Tokyo, Tokyo, 113-0033, Japan.
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Mele M, Leal G, Duarte CB. Role of GABAAR trafficking in the plasticity of inhibitory synapses. J Neurochem 2016; 139:997-1018. [DOI: 10.1111/jnc.13742] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 07/12/2016] [Accepted: 07/13/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Miranda Mele
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Graciano Leal
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
| | - Carlos B. Duarte
- Center for Neuroscience and Cell Biology; University of Coimbra; Coimbra Portugal
- Department of Life Sciences; University of Coimbra; Coimbra Portugal
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38
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Pinto MJ, Almeida RD. Puzzling out presynaptic differentiation. J Neurochem 2016; 139:921-942. [PMID: 27315450 DOI: 10.1111/jnc.13702] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Revised: 05/27/2016] [Accepted: 06/10/2016] [Indexed: 12/24/2022]
Abstract
Proper brain function in the nervous system relies on the accurate establishment of synaptic contacts during development. Countless synapses populate the adult brain in an orderly fashion. In each synapse, a presynaptic terminal loaded with neurotransmitters-containing synaptic vesicles is perfectly aligned to an array of receptors in the postsynaptic membrane. Presynaptic differentiation, which encompasses the events underlying assembly of new presynaptic units, has seen notable advances in recent years. It is now consensual that as a growing axon encounters the receptive dendrites of its partner, presynaptic assembly will be triggered and specified by multiple postsynaptically-derived factors including soluble molecules and cell adhesion complexes. Presynaptic material that reaches these distant sites by axonal transport in the form of pre-assembled packets will be retained and clustered, ultimately giving rise to a presynaptic bouton. This review focuses on the cellular and molecular aspects of presynaptic differentiation in the central nervous system, with a particular emphasis on the identity of the instructive factors and the intracellular processes used by neuronal cells to assemble functional presynaptic terminals. We provide a detailed description of the mechanisms leading to the formation of new presynaptic terminals. In brief, soma-derived packets of pre-assembled material are trafficked to distant axonal sites. Synaptogenic factors from dendritic or glial provenance activate downstream intra-axonal mediators to trigger clustering of passing material and their correct organization into a new presynaptic bouton. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
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Affiliation(s)
- Maria J Pinto
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,PhD Programme in Experimental Biology and Biomedicine (PDBEB), Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - Ramiro D Almeida
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,School of Allied Health Technologies, Polytechnic Institute of Oporto, Vila Nova de Gaia, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
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39
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Regulation of GABAergic synapse development by postsynaptic membrane proteins. Brain Res Bull 2016; 129:30-42. [PMID: 27453545 DOI: 10.1016/j.brainresbull.2016.07.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/06/2016] [Indexed: 02/07/2023]
Abstract
In the adult mammalian brain, GABAergic neurotransmission provides the majority of synaptic inhibition that balances glutamatergic excitatory drive and thereby controls neuronal output. It is generally accepted that synaptogenesis is initiated through highly specific protein-protein interactions mediated by membrane proteins expressed in developing presynaptic terminals and postsynaptic membranes. Accumulating studies have uncovered a number of membrane proteins that regulate different aspects of GABAergic synapse development. In this review, we summarize recent advances in understanding of GABAergic synapse development with a focus on postsynaptic membrane molecules, including receptors, synaptogenic cell adhesion molecules and immunoglobulin superfamily proteins.
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40
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Dutheil S, Watabe I, Sadlaoud K, Tonetto A, Tighilet B. BDNF Signaling Promotes Vestibular Compensation by Increasing Neurogenesis and Remodeling the Expression of Potassium-Chloride Cotransporter KCC2 and GABAA Receptor in the Vestibular Nuclei. J Neurosci 2016; 36:6199-212. [PMID: 27277799 PMCID: PMC6604891 DOI: 10.1523/jneurosci.0945-16.2016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Reactive cell proliferation occurs rapidly in the cat vestibular nuclei (VN) after unilateral vestibular neurectomy (UVN) and has been reported to facilitate the recovery of posturo-locomotor functions. Interestingly, whereas animals experience impairments for several weeks, extraordinary plasticity mechanisms take place in the local microenvironment of the VN: newborn cells survive and acquire different phenotypes, such as microglia, astrocytes, or GABAergic neurons, whereas animals eventually recover completely from their lesion-induced deficits. Because brain-derived neurotrophic factor (BDNF) can modulate vestibular functional recovery and neurogenesis in mammals, in this study, we examined the effect of BDNF chronic intracerebroventricular infusion versus K252a (a Trk receptor antagonist) in our UVN model. Results showed that long-term intracerebroventricular infusion of BDNF accelerated the restoration of vestibular functions and significantly increased UVN-induced neurogenesis, whereas K252a blocked that effect and drastically delayed and prevented the complete restoration of vestibular functions. Further, because the level of excitability in the deafferented VN is correlated with behavioral recovery, we examined the state of neuronal excitability using two specific markers: the cation-chloride cotransporter KCC2 (which determines the hyperpolarizing action of GABA) and GABAA receptors. We report for the first time that, during an early time window after UVN, significant BDNF-dependent remodeling of excitability markers occurs in the brainstem. These data suggest that GABA acquires a transient depolarizing action during recovery from UVN, which potentiates the observed reactive neurogenesis and accelerates vestibular functional recovery. These findings suggest that BDNF and/or KCC2 could represent novel treatment strategies for vestibular pathologies. SIGNIFICANCE STATEMENT In this study, we report for the first time that brain-derived neurotrophic factor potentiates vestibular neurogenesis and significantly accelerates functional recovery after unilateral vestibular injury. We also show that specific markers of excitability, the potassium-chloride cotransporter KCC2 and GABAA receptors, undergo remarkable fluctuations within vestibular nuclei (VN), strongly suggesting that GABA acquires a transient depolarizing action in the VN during the recovery period. This novel plasticity mechanism could explain in part how the system returns to electrophysiological homeostasis between the deafferented and intact VN, considered in the literature to be a key parameter of vestibular compensation. In this context, our results open new perspectives for the development of therapeutic approaches to alleviate the vestibular symptoms and favor vestibular function recovery.
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Affiliation(s)
- Sophie Dutheil
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut 06519
| | - Isabelle Watabe
- Laboratoire de Neurosciences Intégratives et Adaptatives, UMR 7260 Aix-Marseille Université-CNRS, Fédération de Recherche 3C, 13331 Marseille Cedex 03, France, and
| | - Karina Sadlaoud
- Laboratoire de Neurosciences Intégratives et Adaptatives, UMR 7260 Aix-Marseille Université-CNRS, Fédération de Recherche 3C, 13331 Marseille Cedex 03, France, and
| | - Alain Tonetto
- Fédération de Recherche Sciences Chimiques Marseille FR 1739, Pôle PRATIM, 13331 Marseille Cedex 03, France
| | - Brahim Tighilet
- Laboratoire de Neurosciences Intégratives et Adaptatives, UMR 7260 Aix-Marseille Université-CNRS, Fédération de Recherche 3C, 13331 Marseille Cedex 03, France, and
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41
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Dietary Restriction Affects Neuronal Response Property and GABA Synthesis in the Primary Visual Cortex. PLoS One 2016; 11:e0149004. [PMID: 26863207 PMCID: PMC4749323 DOI: 10.1371/journal.pone.0149004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2015] [Accepted: 01/25/2016] [Indexed: 12/02/2022] Open
Abstract
Previous studies have reported inconsistent effects of dietary restriction (DR) on cortical inhibition. To clarify this issue, we examined the response properties of neurons in the primary visual cortex (V1) of DR and control groups of cats using in vivo extracellular single-unit recording techniques, and assessed the synthesis of inhibitory neurotransmitter GABA in the V1 of cats from both groups using immunohistochemical and Western blot techniques. Our results showed that the response of V1 neurons to visual stimuli was significantly modified by DR, as indicated by an enhanced selectivity for stimulus orientations and motion directions, decreased visually-evoked response, lowered spontaneous activity and increased signal-to-noise ratio in DR cats relative to control cats. Further, it was shown that, accompanied with these changes of neuronal responsiveness, GABA immunoreactivity and the expression of a key GABA-synthesizing enzyme GAD67 in the V1 were significantly increased by DR. These results demonstrate that DR may retard brain aging by increasing the intracortical inhibition effect and improve the function of visual cortical neurons in visual information processing. This DR-induced elevation of cortical inhibition may favor the brain in modulating energy expenditure based on food availability.
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42
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Glutamatergic axon-derived BDNF controls GABAergic synaptic differentiation in the cerebellum. Sci Rep 2016; 6:20201. [PMID: 26830657 PMCID: PMC4735332 DOI: 10.1038/srep20201] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 12/23/2015] [Indexed: 01/05/2023] Open
Abstract
To study mechanisms that regulate the construction of inhibitory circuits, we examined the role of brain-derived neurotrophic factor (BDNF) in the assembly of GABAergic inhibitory synapses in the mouse cerebellar cortex. We show that within the cerebellum, BDNF-expressing cells are restricted to the internal granular layer (IGL), but that the BDNF protein is present within mossy fibers which originate from cells located outside of the cerebellum. In contrast to deletion of TrkB, the cognate receptor for BDNF, deletion of Bdnf from cerebellar cell bodies alone did not perturb the localization of pre- or postsynaptic constituents at the GABAergic synapses formed by Golgi cell axons on granule cell dendrites within the IGL. Instead, we found that BDNF derived from excitatory mossy fiber endings controls their differentiation. Our findings thus indicate that cerebellar BDNF is derived primarily from excitatory neurons--precerebellar nuclei/spinal cord neurons that give rise to mossy fibers--and promotes GABAergic synapse formation as a result of release from axons. Thus, within the cerebellum the preferential localization of BDNF to axons enhances the specificity through which BDNF promotes GABAergic synaptic differentiation.
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43
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Prince D, Gu F, Parada I. Antiepileptogenic repair of excitatory and inhibitory synaptic connectivity after neocortical trauma. PROGRESS IN BRAIN RESEARCH 2016; 226:209-27. [DOI: 10.1016/bs.pbr.2016.03.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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44
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Leggio GM, Torrisi SA, Castorina A, Platania CBM, Impellizzeri AAR, Fidilio A, Caraci F, Bucolo C, Drago F, Salomone S. Dopamine D3 receptor-dependent changes in alpha6 GABAA subunit expression in striatum modulate anxiety-like behaviour: Responsiveness and tolerance to diazepam. Eur Neuropsychopharmacol 2015; 25:1427-36. [PMID: 25482686 DOI: 10.1016/j.euroneuro.2014.11.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Revised: 10/09/2014] [Accepted: 11/04/2014] [Indexed: 10/24/2022]
Abstract
Increasing evidence indicates that central dopamine (DA) neurotransmission is involved in pathophysiology of anxiety, in particular the DA receptor subtype 3 (D3R). We previously reported that D3R null mice (D3R(-/-)) exhibit low baseline anxiety levels and that acutely administrated diazepam is more effective in D3R(-/-) than in wild type (WT) when tested in the elevated plus maze test (EPM). Here we tested the hypothesis that genetic deletion or pharmacological blockade of D3R affect GABAA subunit expression, which in turn modulates anxiety-like behaviour as well as responsiveness and tolerance to diazepam. D3R(-/-) mice exhibited tolerance to diazepam (0.5mg/kg, i.p.), assessed by EPM, as fast as after 3 day-treatment, performing similarly to untreated D3R(-/-) mice; conversely, WT exhibited tolerance to diazepam after a 14-21 day-treatment. Analysis of GABAA α6 subunit mRNA expression by qPCR in striatum showed that it was about 15-fold higher in D3R(-/-) than in WT. Diazepam treatment did not modify α6 expression in D3R(-/-), but progressively increased α6 expression in WT, to the level of untreated D3R(-/-) after 14-21 day-treatment. BDNF mRNA expression in striatum was remarkably (>10-fold) increased after 3 days of diazepam-treatment in both WT and D3R(-/-); such expression level, however, slowly declined below control levels, by 14-21 days. Following a 7 day-treatment with the selective D3R antagonist SB277011A, WT exhibited a fast tolerance to diazepam accompanied by a robust increase in α6 subunit expression. In conclusion, genetic deletion or pharmacological blockade of D3R accelerate the development of tolerance to repeated administrations of diazepam and increase α6 subunit expression, a GABAA subunit that has been linked to diazepam insensitivity. Modulation of GABAA receptor by DA transmission may be involved in the mechanisms of anxiety and, if occurring in humans, may have therapeutic relevance following repeated use of drugs targeting D3R.
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Affiliation(s)
- Gian Marco Leggio
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Sebastiano Alfio Torrisi
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | | | - Chiara Bianca Maria Platania
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Agata Antonia Rita Impellizzeri
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Annamaria Fidilio
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Filippo Caraci
- Department of Educational Sciences, Catania University, Catania, Italy; IRCCS Associazione Oasi Maria S.S., Institute for Research on Mental Retardation and Brain Aging, Troina, Italy
| | - Claudio Bucolo
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Filippo Drago
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy
| | - Salvatore Salomone
- Department of Clinical and Molecular Biomedicine, Section of Pharmacology and Biochemistry, Catania University, Catania, Italy.
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45
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Huang T, Ma L, Krimm RF. Postnatal reduction of BDNF regulates the developmental remodeling of taste bud innervation. Dev Biol 2015; 405:225-36. [PMID: 26164656 DOI: 10.1016/j.ydbio.2015.07.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 07/06/2015] [Accepted: 07/07/2015] [Indexed: 01/29/2023]
Abstract
The refinement of innervation is a common developmental mechanism that serves to increase the specificity of connections following initial innervation. In the peripheral gustatory system, the extent to which innervation is refined and how refinement might be regulated is unclear. The initial innervation of taste buds is controlled by brain-derived neurotrophic factor (BDNF). Following initial innervation, taste receptor cells are added and become newly innervated. The connections between the taste receptor cells and nerve fibers are likely to be specific in order to retain peripheral coding mechanisms. Here, we explored the possibility that the down-regulation of BDNF regulates the refinement of taste bud innervation during postnatal development. An analysis of BDNF expression in Bdnf(lacZ/+) mice and real-time reverse transcription polymerase chain reaction (RT-PCR) revealed that BDNF was down-regulated between postnatal day (P) 5 and P10. This reduction in BDNF expression was due to a loss of precursor/progenitor cells that express BDNF, while the expression of BDNF in the subpopulations of taste receptor cells did not change. Gustatory innervation, which was identified by P2X3 immunohistochemistry, was lost around the perimeter where most progenitor/precursor cells are located. In addition, the density of innervation in the taste bud was reduced between P5 and P10, because taste buds increase in size without increasing innervation. This reduction of innervation density was blocked by the overexpression of BDNF in the precursor/progenitor population of taste bud cells. Together these findings indicate that the process of BDNF restriction to a subpopulation of taste receptor cells between P5 and P10, results in a refinement of gustatory innervation. We speculate that this refinement results in an increased specificity of connections between neurons and taste receptor cells during development.
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Affiliation(s)
- Tao Huang
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Liqun Ma
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA
| | - Robin F Krimm
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Louisville, KY 40292, USA.
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46
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Nosheny RL, Belichenko PV, Busse BL, Weissmiller AM, Dang V, Das D, Fahimi A, Salehi A, Smith SJ, Mobley WC. Increased cortical synaptic activation of TrkB and downstream signaling markers in a mouse model of Down Syndrome. Neurobiol Dis 2015; 77:173-90. [PMID: 25753471 DOI: 10.1016/j.nbd.2015.02.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Revised: 02/15/2015] [Accepted: 02/25/2015] [Indexed: 01/01/2023] Open
Abstract
Down Syndrome (DS), trisomy 21, is characterized by synaptic abnormalities and cognitive deficits throughout the lifespan and with development of Alzheimer's disease (AD) neuropathology and progressive cognitive decline in adults. Synaptic abnormalities are also present in the Ts65Dn mouse model of DS, but which synapses are affected and the mechanisms underlying synaptic dysfunction are unknown. Here we show marked increases in the levels and activation status of TrkB and associated signaling proteins in cortical synapses in Ts65Dn mice. Proteomic analysis at the single synapse level of resolution using array tomography (AT) uncovered increased colocalization of activated TrkB with signaling endosome related proteins, and demonstrated increased TrkB signaling. The extent of increases in TrkB signaling differed in each of the cortical layers examined and with respect to the type of synapse, with the most marked increases seen in inhibitory synapses. These findings are evidence of markedly abnormal TrkB-mediated signaling in synapses. They raise the possibility that dysregulated TrkB signaling contributes to synaptic dysfunction and cognitive deficits in DS.
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Affiliation(s)
- R L Nosheny
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA; Department of Molecular and Cellular Physiology, Stanford University, 279 Campus Drive, Stanford, CA 94305, USA.
| | - P V Belichenko
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - B L Busse
- Department of Molecular and Cellular Physiology, Stanford University, 279 Campus Drive, Stanford, CA 94305, USA
| | - A M Weissmiller
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - V Dang
- Department of Psychiatry & Behavioral Sciences, Stanford Medical School, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA
| | - D Das
- Department of Psychiatry & Behavioral Sciences, Stanford Medical School, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA
| | - A Fahimi
- Department of Psychiatry & Behavioral Sciences, Stanford Medical School, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA
| | - A Salehi
- Department of Psychiatry & Behavioral Sciences, Stanford Medical School, VA Palo Alto Health Care System, 3801 Miranda Avenue, Palo Alto, CA 94304, USA
| | - S J Smith
- Department of Molecular and Cellular Physiology, Stanford University, 279 Campus Drive, Stanford, CA 94305, USA
| | - W C Mobley
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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47
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Pro-brain-derived neurotrophic factor inhibits GABAergic neurotransmission by activating endocytosis and repression of GABAA receptors. J Neurosci 2015; 34:13516-34. [PMID: 25274828 DOI: 10.1523/jneurosci.2069-14.2014] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
GABA is the canonical inhibitory neurotransmitter in the CNS. This inhibitory action is largely mediated by GABA type A receptors (GABAARs). Among the many factors controlling GABAergic transmission, brain-derived neurotrophic factor (BDNF) appears to play a major role in regulating synaptic inhibition. Recent findings have demonstrated that BDNF can be released as a precursor (proBDNF). Although the role of mature BDNF on GABAergic synaptogenesis and maintenance has been well studied, an important question still unanswered is whether secreted proBDNF might affect GABAergic neurotransmission. Here, we have used 14 d in vitro primary culture of hippocampal neurons and ex vivo preparations from rats to study the function of proBDNF in regulation of GABAAR trafficking and activity. We demonstrate that proBDNF impairs GABAergic transmission by the activation of two distinct pathways: (1) a RhoA-Rock-PTEN pathway that decreases the phosphorylation levels of GABAAR, thus affecting receptor function and triggering endocytosis and degradation of internalized receptors, and (2) a JAK-STAT-ICER pathway leading to the repression of GABAARs synthesis. These effects lead to the diminution of GABAergic synapses and are correlated with a decrease in GABAergic synaptic currents. These results revealed new functions for proBDNF-p75 neurotrophin receptor signaling pathway in the control of the efficacy of GABAergic synaptic activity by regulating the trafficking and synthesis of GABAARs at inhibitory synapses.
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48
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Luscher B, Fuchs T. GABAergic control of depression-related brain states. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2015; 73:97-144. [PMID: 25637439 DOI: 10.1016/bs.apha.2014.11.003] [Citation(s) in RCA: 88] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The GABAergic deficit hypothesis of major depressive disorders (MDDs) posits that reduced γ-aminobutyric acid (GABA) concentration in brain, impaired function of GABAergic interneurons, altered expression and function of GABA(A) receptors, and changes in GABAergic transmission dictated by altered chloride homeostasis can contribute to the etiology of MDD. Conversely, the hypothesis posits that the efficacy of currently used antidepressants is determined by their ability to enhance GABAergic neurotransmission. We here provide an update for corresponding evidence from studies of patients and preclinical animal models of depression. In addition, we propose an explanation for the continued lack of genetic evidence that explains the considerable heritability of MDD. Lastly, we discuss how alterations in GABAergic transmission are integral to other hypotheses of MDD that emphasize (i) the role of monoaminergic deficits, (ii) stress-based etiologies, (iii) neurotrophic deficits, and (iv) the neurotoxic and neural circuit-impairing consequences of chronic excesses of glutamate. We propose that altered GABAergic transmission serves as a common denominator of MDD that can account for all these other hypotheses and that plays a causal and common role in diverse mechanistic etiologies of depressive brain states and in the mechanism of action of current antidepressant drug therapies.
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Affiliation(s)
- Bernhard Luscher
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Center for Molecular Investigation of Neurological Disorders, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA.
| | - Thomas Fuchs
- Department of Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania, USA; Center for Molecular Investigation of Neurological Disorders, The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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49
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Adachi N, Numakawa T, Richards M, Nakajima S, Kunugi H. New insight in expression, transport, and secretion of brain-derived neurotrophic factor: Implications in brain-related diseases. World J Biol Chem 2014; 5:409-428. [PMID: 25426265 PMCID: PMC4243146 DOI: 10.4331/wjbc.v5.i4.409] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2014] [Revised: 06/10/2014] [Accepted: 08/31/2014] [Indexed: 02/05/2023] Open
Abstract
Brain-derived neurotrophic factor (BDNF) attracts increasing attention from both research and clinical fields because of its important functions in the central nervous system. An adequate amount of BDNF is critical to develop and maintain normal neuronal circuits in the brain. Given that loss of BDNF function has been reported in the brains of patients with neurodegenerative or psychiatric diseases, understanding basic properties of BDNF and associated intracellular processes is imperative. In this review, we revisit the gene structure, transcription, translation, transport and secretion mechanisms of BDNF. We also introduce implications of BDNF in several brain-related diseases including Alzheimer’s disease, Huntington’s disease, depression and schizophrenia.
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50
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Shinoda Y, Ahmed S, Ramachandran B, Bharat V, Brockelt D, Altas B, Dean C. BDNF enhances spontaneous and activity-dependent neurotransmitter release at excitatory terminals but not at inhibitory terminals in hippocampal neurons. Front Synaptic Neurosci 2014; 6:27. [PMID: 25426063 PMCID: PMC4226143 DOI: 10.3389/fnsyn.2014.00027] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2014] [Accepted: 10/21/2014] [Indexed: 11/30/2022] Open
Abstract
Brain-derived neurotrophic factor (BDNF) is widely reported to enhance synaptic vesicle (SV) exocytosis and neurotransmitter release. But it is still unclear whether BDNF enhances SV recycling at excitatory terminals only, or at both excitatory and inhibitory terminals. In the present study, in a direct comparison using cultured rat hippocampal neurons, we demonstrate that BDNF enhances both spontaneous and activity-dependent neurotransmitter release from excitatory terminals, but not from inhibitory terminals. BDNF treatment for 5 min or 48 h increased both spontaneous and activity-induced anti-synaptotagmin1 (SYT1) antibody uptake at excitatory terminals marked with vGluT1. Conversely, BDNF treatment did not enhance spontaneous or activity-induced uptake of anti-SYT1 antibodies in inhibitory terminals marked with vGAT. Time-lapse imaging of FM1-43 dye destaining in excitatory and inhibitory terminals visualized by post-hoc immunostaining of vGluT1 and vGAT also showed the same result: The rate of spontaneous and activity-induced destaining was increased by BDNF at excitatory synapses, but not at inhibitory synapses. These data demonstrate that BDNF enhances SV exocytosis in excitatory but not inhibitory terminals. Moreover, BDNF enhanced evoked SV exocytosis, even if vesicles were loaded under spontaneous vesicle recycling conditions. Thus, BDNF enhances both spontaneous and activity-dependent neurotransmitter release on both short and long time-scales, by the same mechanism.
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Affiliation(s)
- Yo Shinoda
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany ; Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science Chiba, Japan
| | - Saheeb Ahmed
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Binu Ramachandran
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Vinita Bharat
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - David Brockelt
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Bekir Altas
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
| | - Camin Dean
- Trans-synaptic Signaling Group, European Neuroscience Institute Goettingen, Germany
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