1
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Caya-Bissonnette L, Béïque JC. Half a century legacy of long-term potentiation. Curr Biol 2024; 34:R640-R662. [PMID: 38981433 DOI: 10.1016/j.cub.2024.05.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
In 1973, two papers from Bliss and Lømo and from Bliss and Gardner-Medwin reported that high-frequency synaptic stimulation in the dentate gyrus of rabbits resulted in a long-lasting increase in synaptic strength. This form of synaptic plasticity, commonly referred to as long-term potentiation (LTP), was immediately considered as an attractive mechanism accounting for the ability of the brain to store information. In this historical piece looking back over the past 50 years, we discuss how these two landmark contributions directly motivated a colossal research effort and detail some of the resulting milestones that have shaped our evolving understanding of the molecular and cellular underpinnings of LTP. We highlight the main features of LTP, cover key experiments that defined its induction and expression mechanisms, and outline the evidence supporting a potential role of LTP in learning and memory. We also briefly explore some ramifications of LTP on network stability, consider current limitations of LTP as a model of associative memory, and entertain future research orientations.
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Affiliation(s)
- Léa Caya-Bissonnette
- Graduate Program in Neuroscience, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Brain and Mind Research Institute's Centre for Neural Dynamics and Artificial Intelligence, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada
| | - Jean-Claude Béïque
- Brain and Mind Research Institute's Centre for Neural Dynamics and Artificial Intelligence, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada; Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 ch. Smyth Road (3501N), Ottawa, ON K1H 8M5, Canada.
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2
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Wang B, Torok Z, Duffy A, Bell DG, Wongso S, Velho TAF, Fairhall AL, Lois C. Unsupervised restoration of a complex learned behavior after large-scale neuronal perturbation. Nat Neurosci 2024; 27:1176-1186. [PMID: 38684893 DOI: 10.1038/s41593-024-01630-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 03/26/2024] [Indexed: 05/02/2024]
Abstract
Reliable execution of precise behaviors requires that brain circuits are resilient to variations in neuronal dynamics. Genetic perturbation of the majority of excitatory neurons in HVC, a brain region involved in song production, in adult songbirds with stereotypical songs triggered severe degradation of the song. The song fully recovered within 2 weeks, and substantial improvement occurred even when animals were prevented from singing during the recovery period, indicating that offline mechanisms enable recovery in an unsupervised manner. Song restoration was accompanied by increased excitatory synaptic input to neighboring, unmanipulated neurons in the same brain region. A model inspired by the behavioral and electrophysiological findings suggests that unsupervised single-cell and population-level homeostatic plasticity rules can support the functional restoration after large-scale disruption of networks that implement sequential dynamics. These observations suggest the existence of cellular and systems-level restorative mechanisms that ensure behavioral resilience.
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Affiliation(s)
- Bo Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
| | - Zsofia Torok
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Alison Duffy
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
- Computational Neuroscience Center, University of Washington, Seattle, WA, USA
| | - David G Bell
- Computational Neuroscience Center, University of Washington, Seattle, WA, USA
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Shelyn Wongso
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Tarciso A F Velho
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA
| | - Adrienne L Fairhall
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
- Computational Neuroscience Center, University of Washington, Seattle, WA, USA
- Department of Physics, University of Washington, Seattle, WA, USA
| | - Carlos Lois
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, USA.
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3
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Rafael A, Tizzoni M, Justet C, Cairus A, Abudara V, Vitureira N. Glial Cx43 hemichannels and neuronal Panx1 hemichannels and P2X7 receptors orchestrate presynaptic homeostatic plasticity. Cell Signal 2024; 117:111113. [PMID: 38395185 DOI: 10.1016/j.cellsig.2024.111113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 02/14/2024] [Accepted: 02/19/2024] [Indexed: 02/25/2024]
Abstract
The emerging role of glial cells in modulating neuronal excitability and synaptic strength is a growing field in neuroscience. In recent years, a pivotal role of gliotransmission in homeostatic presynaptic plasticity has been highlighted and glial-derived ATP arises as a key contributor. However, very little is known about the glial non-vesicular ATP-release pathway and how ATP participates in the modulation of synaptic strength. Here, we investigated the functional changes occurring in neurons upon chronic inactivity and the role of the purinergic signaling, connexin43 and pannexin1 hemichannels in this process. By using hippocampal dissociated cultures, we showed that blocking connexin43 and pannexin1 hemichannels decreases the amount of extracellular ATP. Moreover, Ca2+ imaging assays using Fluo-4/AM revealed that blocking connexin43, neuronal P2X7Rs and pannexin1 hemichannels decreases the amount of basal Ca2+ in neurons. A significant impairment in synaptic vesicle pool size was also evidenced under these conditions. Interestingly, rescue experiments where Panx1HCs are blocked showed that the compensatory adjustment of cytosolic Ca2+ was recovered after P2X7Rs activation, suggesting that Panx1 acts downstream P2X7Rs. These changes were accompanied by a modulation of neuronal permeability, as revealed by ethidium bromide uptake experiments. In particular, the permeability of neuronal P2X7Rs and pannexin1 hemichannels is increased upon 24 h of inactivity. Taken together, we have uncovered a role for connexin43-dependent ATP release and neuronal P2X7Rs and pannexin1 hemichannels in the adjustment of presynaptic strength by modulating neuronal permeability, the entrance of Ca2+ into neurons and the size of the recycling pool of synaptic vesicles.
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Affiliation(s)
- Alberto Rafael
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay
| | - Marina Tizzoni
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay
| | - Cristian Justet
- Departamento de Bioquímica, Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay
| | - Andrea Cairus
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay
| | - Verónica Abudara
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay
| | - Nathalia Vitureira
- Departamento de Fisiología, Facultad de Medicina, Universidad de la República, Avenida Gral. Flores 2125, CP 11800, Montevideo, Uruguay.
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4
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Sun SED, Levenstein D, Li B, Mandelberg N, Chenouard N, Suutari BS, Sanchez S, Tian G, Rinzel J, Buzsáki G, Tsien RW. Synaptic homeostasis transiently leverages Hebbian mechanisms for a multiphasic response to inactivity. Cell Rep 2024; 43:113839. [PMID: 38507409 DOI: 10.1016/j.celrep.2024.113839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Revised: 12/19/2023] [Accepted: 02/05/2024] [Indexed: 03/22/2024] Open
Abstract
Homeostatic regulation of synapses is vital for nervous system function and key to understanding a range of neurological conditions. Synaptic homeostasis is proposed to operate over hours to counteract the destabilizing influence of long-term potentiation (LTP) and long-term depression (LTD). The prevailing view holds that synaptic scaling is a slow first-order process that regulates postsynaptic glutamate receptors and fundamentally differs from LTP or LTD. Surprisingly, we find that the dynamics of scaling induced by neuronal inactivity are not exponential or monotonic, and the mechanism requires calcineurin and CaMKII, molecules dominant in LTD and LTP. Our quantitative model of these enzymes reconstructs the unexpected dynamics of homeostatic scaling and reveals how synapses can efficiently safeguard future capacity for synaptic plasticity. This mechanism of synaptic adaptation supports a broader set of homeostatic changes, including action potential autoregulation, and invites further inquiry into how such a mechanism varies in health and disease.
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Affiliation(s)
- Simón E D Sun
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA
| | - Daniel Levenstein
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, 3810 University Street, Montreal, QC, Canada
| | - Boxing Li
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and the Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Nataniel Mandelberg
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Nicolas Chenouard
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA; Sorbonne Université, INSERM U1127, UMR CNRS 7225, Institut du Cerveau (ICM), 47 bld de l'hôpital, 75013 Paris, France
| | - Benjamin S Suutari
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Sandrine Sanchez
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Guoling Tian
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - John Rinzel
- Center for Neural Science, New York University, New York, NY 10003, USA
| | - György Buzsáki
- Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA
| | - Richard W Tsien
- Center for Neural Science, New York University, New York, NY 10003, USA; Department of Neuroscience and Physiology, Neuroscience Institute, New York University Langone Health, New York, NY 10016, USA.
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5
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Ntoulas G, Brakatselos C, Nakas G, Asprogerakas MZ, Delis F, Leontiadis LJ, Trompoukis G, Papatheodoropoulos C, Gkikas D, Valakos D, Vatsellas G, Politis PK, Polissidis A, Antoniou K. Multi-level profiling of the Fmr1 KO rat unveils altered behavioral traits along with aberrant glutamatergic function. Transl Psychiatry 2024; 14:104. [PMID: 38378836 PMCID: PMC10879511 DOI: 10.1038/s41398-024-02815-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/19/2024] [Accepted: 02/01/2024] [Indexed: 02/22/2024] Open
Abstract
Fragile X syndrome (FXS) is the most common cause of inherited intellectual disabilities and the most prevalent monogenic cause of autism. Although the knockout (KO) of the Fmr1 gene homolog in mice is primarily used for elucidating the neurobiological substrate of FXS, there is limited association of the experimental data with the pathophysiological condition in humans. The use of Fmr1 KO rats offers additional translational validity in this regard. Therefore, we employed a multi-level approach to study the behavioral profile and the glutamatergic and GABAergic neurotransmission status in pathophysiology-associated brain structures of Fmr1 KO rats, including the recordings of evoked and spontaneous field potentials from hippocampal slices, paralleled with next-generation RNA sequencing (RNA-seq). We found that these rats exhibit hyperactivity and cognitive deficits, along with characteristic bidirectional glutamatergic and GABAergic alterations in the prefrontal cortex and the hippocampus. These results are coupled to affected excitability and local inhibitory processes in the hippocampus, along with a specific transcriptional profile, highlighting dysregulated hippocampal network activity in KO rats. Overall, our data provide novel insights concerning the biobehavioral profile of FmR1 KO rats and translationally upscales our understanding on pathophysiology and symptomatology of FXS syndrome.
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Affiliation(s)
- George Ntoulas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Charalampos Brakatselos
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Gerasimos Nakas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Michail-Zois Asprogerakas
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Foteini Delis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
| | - Leonidas J Leontiadis
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | - George Trompoukis
- Laboratory of Neurophysiology, Department of Medicine, University of Patras, Rion, Greece
| | | | - Dimitrios Gkikas
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Dimitrios Valakos
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Giannis Vatsellas
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Panagiotis K Politis
- Center of Basic Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Alexia Polissidis
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece
- Center of Clinical, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, Athens, Greece
| | - Katerina Antoniou
- Department of Pharmacology, Faculty of Medicine, School of Health Sciences University of Ioannina, Ioannina, Greece.
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6
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Koesters AG, Rich MM, Engisch KL. Diverging from the Norm: Reevaluating What Miniature Excitatory Postsynaptic Currents Tell Us about Homeostatic Synaptic Plasticity. Neuroscientist 2024; 30:49-70. [PMID: 35904350 DOI: 10.1177/10738584221112336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The idea that the nervous system maintains a set point of network activity and homeostatically returns to that set point in the face of dramatic disruption-during development, after injury, in pathologic states, and during sleep/wake cycles-is rapidly becoming accepted as a key plasticity behavior, placing it alongside long-term potentiation and depression. The dramatic growth in studies of homeostatic synaptic plasticity of miniature excitatory synaptic currents (mEPSCs) is attributable, in part, to the simple yet elegant mechanism of uniform multiplicative scaling proposed by Turrigiano and colleagues: that neurons sense their own activity and globally multiply the strength of every synapse by a single factor to return activity to the set point without altering established differences in synaptic weights. We have recently shown that for mEPSCs recorded from control and activity-blocked cultures of mouse cortical neurons, the synaptic scaling factor is not uniform but is close to 1 for the smallest mEPSC amplitudes and progressively increases as mEPSC amplitudes increase, which we term divergent scaling. Using insights gained from simulating uniform multiplicative scaling, we review evidence from published studies and conclude that divergent synaptic scaling is the norm rather than the exception. This conclusion has implications for hypotheses about the molecular mechanisms underlying synaptic scaling.
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Affiliation(s)
- Andrew G Koesters
- Department of Behavior, Cognition, and Neurophysiology, Environmental Health Effects Laboratory, Naval Medical Research Unit-Dayton, Wright-Patterson AFB, OH, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology, and Physiology, College of Science and Mathematics, and Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
| | - Kathrin L Engisch
- Department of Neuroscience, Cell Biology, and Physiology, College of Science and Mathematics, and Boonshoft School of Medicine, Wright State University, Dayton, OH, USA
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7
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Wakazono Y, Midorikawa R, Takamiya K. Temporal and quantitative analysis of the functional expression of Ca 2+-permeable AMPA receptors during LTP. Neurosci Res 2024; 198:21-29. [PMID: 37429464 DOI: 10.1016/j.neures.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 06/26/2023] [Accepted: 07/05/2023] [Indexed: 07/12/2023]
Abstract
In the present study, we attempted to temporally and quantitatively analyze the functional contributions of Ca2+-permeable (CP) α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) during long-term potentiation (LTP) expression using electrophysiological and pharmacological approaches. In hippocampal CA1 neurons, using 1-naphthyl acetyl spermine (NASPM), a CP-AMPAR antagonist, we began by demonstrating that NASPM-sensitive components, probably including the GluA1 homomer, functionally contributed to about 15% of AMPAR-mediated EPSC amplitude in basal conditions. Then, when NASPM was treated at different time points (3-30 min) after LTP induction, it was found that LTP was almost completely impaired at 3 or 10 min but maintained at 20 or 30 min, although its potentiation was reduced. Further temporal and quantitative analysis revealed that the functional expression of CP-AMPARs began increasing approximately 20 min after LTP induction and reached more than twice the basal level at 30 min. These results suggest that CP-AMPARs in the first 3-10 min of LTP might play an important role in LTP maintenance. Moreover, their decay time was also significantly increased at 30 min, suggesting that CP-AMPARs changed not only quantitatively in LTP but also qualitatively.
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Affiliation(s)
- Yoshihiko Wakazono
- Department of Neuroscience, Faculty of Medicine, University of Miyazaki, Japan; Laboratory of Biophysical Research, Frontier Science Research Center, University of Miyazaki, Japan
| | - Ryosuke Midorikawa
- Department of Neuroscience, Faculty of Medicine, University of Miyazaki, Japan
| | - Kogo Takamiya
- Department of Neuroscience, Faculty of Medicine, University of Miyazaki, Japan; Laboratory of Biophysical Research, Frontier Science Research Center, University of Miyazaki, Japan.
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8
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Müller-Komorowska D, Kuru B, Beck H, Braganza O. Phase information is conserved in sparse, synchronous population-rate-codes via phase-to-rate recoding. Nat Commun 2023; 14:6106. [PMID: 37777512 PMCID: PMC10543394 DOI: 10.1038/s41467-023-41803-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 09/19/2023] [Indexed: 10/02/2023] Open
Abstract
Neural computation is often traced in terms of either rate- or phase-codes. However, most circuit operations will simultaneously affect information across both coding schemes. It remains unclear how phase and rate coded information is transmitted, in the face of continuous modification at consecutive processing stages. Here, we study this question in the entorhinal cortex (EC)- dentate gyrus (DG)- CA3 system using three distinct computational models. We demonstrate that DG feedback inhibition leverages EC phase information to improve rate-coding, a computation we term phase-to-rate recoding. Our results suggest that it i) supports the conservation of phase information within sparse rate-codes and ii) enhances the efficiency of plasticity in downstream CA3 via increased synchrony. Given the ubiquity of both phase-coding and feedback circuits, our results raise the question whether phase-to-rate recoding is a recurring computational motif, which supports the generation of sparse, synchronous population-rate-codes in areas beyond the DG.
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Affiliation(s)
- Daniel Müller-Komorowska
- Neural Coding and Brain Computing Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, 904-0495, Japan.
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.
| | - Baris Kuru
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
| | - Heinz Beck
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V, Bonn, Germany
| | - Oliver Braganza
- Institute for Experimental Epileptology and Cognition Research, University of Bonn, Bonn, Germany.
- Institute for Socio-Economics, University of Duisburg-Essen, Duisburg, Germany.
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9
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Ueda J, Uemura N, Ishimoto T, Taguchi T, Sawamura M, Nakanishi E, Ikuno M, Matsuzawa S, Yamakado H, Takahashi R. Ca 2+ -Calmodulin-Calcineurin Signaling Modulates α-Synuclein Transmission. Mov Disord 2023; 38:1056-1067. [PMID: 37066491 DOI: 10.1002/mds.29401] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 03/08/2023] [Accepted: 03/20/2023] [Indexed: 04/18/2023] Open
Abstract
BACKGROUND The intercellular transmission of pathogenic proteins plays a crucial role in the progression of neurodegenerative diseases. Previous research has shown that the neuronal uptake of such proteins is activity-dependent; however, the detailed mechanisms underlying activity-dependent α-synuclein transmission in Parkinson's disease remain unclear. OBJECTIVE To examine whether α-synuclein transmission is affected by Ca2+ -calmodulin-calcineurin signaling in cultured cells and mouse models of Parkinson's disease. METHODS Mouse primary hippocampal neurons were used to examine the effects of the modulation of Ca2+ -calmodulin-calcineurin signaling on the neuronal uptake of α-synuclein preformed fibrils. The effects of modulating Ca2+ -calmodulin-calcineurin signaling on the development of α-synuclein pathology were examined using a mouse model injected with α-synuclein preformed fibrils. RESULTS Modulation of Ca2+ -calmodulin-calcineurin signaling by inhibiting voltage-gated Ca2+ channels, calmodulin, and calcineurin blocked the neuronal uptake of α-synuclein preformed fibrils via macropinocytosis. Different subtypes of voltage-gated Ca2+ channel differentially contributed to the neuronal uptake of α-synuclein preformed fibrils. In wild-type mice inoculated with α-synuclein preformed fibrils, we found that inhibiting calcineurin ameliorated the development of α-synuclein pathology. CONCLUSION Our data suggest that Ca2+ -calmodulin-calcineurin signaling modulates α-synuclein transmission and has potential as a therapeutic target for Parkinson's disease. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jun Ueda
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Norihito Uemura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomoyuki Ishimoto
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomoyuki Taguchi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masanori Sawamura
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Etsuro Nakanishi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masashi Ikuno
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shuichi Matsuzawa
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Hodaka Yamakado
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryosuke Takahashi
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan
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10
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Barrio-Alonso E, Lituma PJ, Notaras MJ, Albero R, Bouchekioua Y, Wayland N, Stankovic IN, Jain T, Gao S, Calderon DP, Castillo PE, Colak D. Circadian protein TIMELESS regulates synaptic function and memory by modulating cAMP signaling. Cell Rep 2023; 42:112375. [PMID: 37043347 PMCID: PMC10564971 DOI: 10.1016/j.celrep.2023.112375] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 03/07/2023] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
The regulation of neurons by circadian clock genes is thought to contribute to the maintenance of neuronal functions that ultimately underlie animal behavior. However, the impact of specific circadian genes on cellular and molecular mechanisms controlling synaptic plasticity and cognitive function remains elusive. Here, we show that the expression of the circadian protein TIMELESS displays circadian rhythmicity in the mammalian hippocampus. We identify TIMELESS as a chromatin-bound protein that targets synaptic-plasticity-related genes such as phosphodiesterase 4B (Pde4b). By promoting Pde4b transcription, TIMELESS negatively regulates cAMP signaling to modulate AMPA receptor GluA1 function and influence synaptic plasticity. Conditional deletion of Timeless in the adult forebrain impairs working and contextual fear memory in mice. These cognitive phenotypes were accompanied by attenuation of hippocampal Schaffer-collateral synapse long-term potentiation. Together, these data establish a neuron-specific function of mammalian TIMELESS by defining a mechanism that regulates synaptic plasticity and cognitive function.
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Affiliation(s)
- Estibaliz Barrio-Alonso
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Pablo J Lituma
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Michael J Notaras
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Robert Albero
- Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Youcef Bouchekioua
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | - Natalie Wayland
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Isidora N Stankovic
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA
| | - Tanya Jain
- Program of Neurosciences, Weill Graduate School of Medical Sciences of Cornell University, New York, NY, USA
| | - Sijia Gao
- Department of Anesthesiology, Weill Cornell Medical College, New York, NY, USA
| | | | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Dilek Colak
- Center for Neurogenetics, Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, Cornell University, New York, NY, USA; Gale & Ira Drukier Institute for Children's Health, Weill Cornell Medical College, Cornell University, New York, NY, USA.
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11
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Wang Y, Lin J, Li J, Yan L, Li W, He X, Ma H. Chronic Neuronal Inactivity Utilizes the mTOR-TFEB Pathway to Drive Transcription-Dependent Autophagy for Homeostatic Up-Scaling. J Neurosci 2023; 43:2631-2652. [PMID: 36868861 PMCID: PMC10089247 DOI: 10.1523/jneurosci.0146-23.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023] Open
Abstract
Activity-dependent changes in protein expression are critical for neuronal plasticity, a fundamental process for the processing and storage of information in the brain. Among the various forms of plasticity, homeostatic synaptic up-scaling is unique in that it is induced primarily by neuronal inactivity. However, precisely how the turnover of synaptic proteins occurs in this homeostatic process remains unclear. Here, we report that chronically inhibiting neuronal activity in primary cortical neurons prepared from embryonic day (E)18 Sprague Dawley rats (both sexes) induces autophagy, thereby regulating key synaptic proteins for up-scaling. Mechanistically, chronic neuronal inactivity causes dephosphorylation of ERK and mTOR, which induces transcription factor EB (TFEB)-mediated cytonuclear signaling and drives transcription-dependent autophagy to regulate αCaMKII and PSD95 during synaptic up-scaling. Together, these findings suggest that mTOR-dependent autophagy, which is often triggered by metabolic stressors such as starvation, is recruited and sustained during neuronal inactivity to maintain synaptic homeostasis, a process that ensures proper brain function and if impaired can cause neuropsychiatric disorders such as autism.SIGNIFICANCE STATEMENT In the mammalian brain, protein turnover is tightly controlled by neuronal activation to ensure key neuronal functions during long-lasting synaptic plasticity. However, a long-standing question is how this process occurs during synaptic up-scaling, a process that requires protein turnover but is induced by neuronal inactivation. Here, we report that mTOR-dependent signaling, which is often triggered by metabolic stressors such as starvation, is "hijacked" by chronic neuronal inactivation, which then serves as a nucleation point for transcription factor EB (TFEB) cytonuclear signaling that drives transcription-dependent autophagy for up-scaling. These results provide the first evidence of a physiological role of mTOR-dependent autophagy in enduing neuronal plasticity, thereby connecting major themes in cell biology and neuroscience via a servo loop that mediates autoregulation in the brain.
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Affiliation(s)
- Yang Wang
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Jingran Lin
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Jiarui Li
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Lu Yan
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Wenwen Li
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Xingzhi He
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Huan Ma
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
- Research Units for Emotion and Emotion disorders, Chinese Academy of Medical Sciences, Beijing 100050, China
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12
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Valakh V, Wise D, Zhu XA, Sha M, Fok J, Van Hooser SD, Schectman R, Cepeda I, Kirk R, O'Toole SM, Nelson SB. A transcriptional constraint mechanism limits the homeostatic response to activity deprivation in mammalian neocortex. eLife 2023; 12:e74899. [PMID: 36749029 PMCID: PMC10010687 DOI: 10.7554/elife.74899] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Healthy neuronal networks rely on homeostatic plasticity to maintain stable firing rates despite changing synaptic drive. These mechanisms, however, can themselves be destabilizing if activated inappropriately or excessively. For example, prolonged activity deprivation can lead to rebound hyperactivity and seizures. While many forms of homeostasis have been described, whether and how the magnitude of homeostatic plasticity is constrained remains unknown. Here, we uncover negative regulation of cortical network homeostasis by the PARbZIP family of transcription factors. In cortical slice cultures made from knockout mice lacking all three of these factors, the network response to prolonged activity withdrawal measured with calcium imaging is much stronger, while baseline activity is unchanged. Whole-cell recordings reveal an exaggerated increase in the frequency of miniature excitatory synaptic currents reflecting enhanced upregulation of recurrent excitatory synaptic transmission. Genetic analyses reveal that two of the factors, Hlf and Tef, are critical for constraining plasticity and for preventing life-threatening seizures. These data indicate that transcriptional activation is not only required for many forms of homeostatic plasticity but is also involved in restraint of the response to activity deprivation.
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Affiliation(s)
- Vera Valakh
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Derek Wise
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Xiaoyue Aelita Zhu
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Mingqi Sha
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Jaidyn Fok
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Stephen D Van Hooser
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Robin Schectman
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Isabel Cepeda
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Ryan Kirk
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Sean M O'Toole
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Sacha B Nelson
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
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13
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Biasetti L, Rey S, Fowler M, Ratnayaka A, Fennell K, Smith C, Marshall K, Hall C, Vargas-Caballero M, Serpell L, Staras K. Elevated amyloid beta disrupts the nanoscale organization and function of synaptic vesicle pools in hippocampal neurons. Cereb Cortex 2023; 33:1263-1276. [PMID: 35368053 PMCID: PMC9930632 DOI: 10.1093/cercor/bhac134] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 02/02/2022] [Accepted: 03/07/2022] [Indexed: 11/14/2022] Open
Abstract
Alzheimer's disease is linked to increased levels of amyloid beta (Aβ) in the brain, but the mechanisms underlying neuronal dysfunction and neurodegeneration remain enigmatic. Here, we investigate whether organizational characteristics of functional presynaptic vesicle pools, key determinants of information transmission in the central nervous system, are targets for elevated Aβ. Using an optical readout method in cultured hippocampal neurons, we show that acute Aβ42 treatment significantly enlarges the fraction of functional vesicles at individual terminals. We observe the same effect in a chronically elevated Aβ transgenic model (APPSw,Ind) using an ultrastructure-function approach that provides detailed information on nanoscale vesicle pool positioning. Strikingly, elevated Aβ is correlated with excessive accumulation of recycled vesicles near putative endocytic sites, which is consistent with deficits in vesicle retrieval pathways. Using the glutamate reporter, iGluSnFR, we show that there are parallel functional consequences, where ongoing information signaling capacity is constrained. Treatment with levetiracetam, an antiepileptic that dampens synaptic hyperactivity, partially rescues these transmission defects. Our findings implicate organizational and dynamic features of functional vesicle pools as targets in Aβ-driven synaptic impairment, suggesting that interventions to relieve the overloading of vesicle retrieval pathways might have promising therapeutic value.
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Affiliation(s)
- Luca Biasetti
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Stephanie Rey
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- National Physical Laboratory, Middlesex, TW11 0LW, United Kingdom
| | - Milena Fowler
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Arjuna Ratnayaka
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
- Faculty of Medicine, University of Southampton, SO17 1BJ, United Kingdom
| | - Kate Fennell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Smith
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Karen Marshall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Catherine Hall
- Sussex Neuroscience, School of Psychology, University of Sussex, Brighton, BN1 9QH, United Kingdom
| | - Mariana Vargas-Caballero
- School of Biological Sciences, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - Louise Serpell
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, BN1 9QG, United Kingdom
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14
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Cordella F, Ferrucci L, D’Antoni C, Ghirga S, Brighi C, Soloperto A, Gigante Y, Ragozzino D, Bezzi P, Di Angelantonio S. Human iPSC-Derived Cortical Neurons Display Homeostatic Plasticity. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111884. [PMID: 36431019 PMCID: PMC9696876 DOI: 10.3390/life12111884] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 11/16/2022]
Abstract
Maintaining the excitability of neurons and circuits is fundamental for healthy brain functions. The global compensatory increase in excitatory synaptic strength, in response to decreased activity, is one of the main homeostatic mechanisms responsible for such regulation. This type of plasticity has been extensively characterized in rodents in vivo and in vitro, but few data exist on human neurons maturation. We have generated an in vitro cortical model system, based on differentiated human-induced pluripotent stem cells, chronically treated with tetrodotoxin, to investigate homeostatic plasticity at different developmental stages. Our findings highlight the presence of homeostatic plasticity in human cortical networks and show that the changes in synaptic strength are due to both pre- and post-synaptic mechanisms. Pre-synaptic plasticity involves the potentiation of neurotransmitter release machinery, associated to an increase in synaptic vesicle proteins expression. At the post-synaptic level, we report an increase in the expression of post-synaptic density proteins, involved in glutamatergic receptor anchoring. These results extend our understanding of neuronal homeostasis and reveal the developmental regulation of its expression in human cortical networks. Since induced pluripotent stem cell-derived neurons can be obtained from patients with neurodevelopmental and neurodegenerative diseases, our platform offers a versatile model for assessing human neural plasticity under physiological and pathological conditions.
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Affiliation(s)
- Federica Cordella
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Laura Ferrucci
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Chiara D’Antoni
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Silvia Ghirga
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Carlo Brighi
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
- CrestOptics S.p.A., Via di Torre Rossa 66, 00165 Rome, Italy
| | - Alessandro Soloperto
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
| | - Ylenia Gigante
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
- D-Tails s.r.l., Via di Torre Rossa 66, 00165 Rome, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Santa Lucia Foundation, European Center for Brain Research, 00143 Rome, Italy
| | - Paola Bezzi
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Department of Fundamental Neurosciences, University of Lausanne, 1015 Lausanne, Switzerland
- Correspondence: or (P.B.); or (S.D.A.)
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Center for Life Nano- & Neuro-Science of Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy
- D-Tails s.r.l., Via di Torre Rossa 66, 00165 Rome, Italy
- Correspondence: or (P.B.); or (S.D.A.)
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15
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Bar L, Shalom L, Lezmy J, Peretz A, Attali B. Excitatory and inhibitory hippocampal neurons differ in their homeostatic adaptation to chronic M-channel modulation. Front Mol Neurosci 2022; 15:972023. [PMID: 36311018 PMCID: PMC9614320 DOI: 10.3389/fnmol.2022.972023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/27/2022] [Indexed: 12/03/2022] Open
Abstract
A large body of studies has investigated bidirectional homeostatic plasticity both in vitro and in vivo using numerous pharmacological manipulations of activity or behavioral paradigms. However, these experiments rarely explored in the same cellular system the bidirectionality of the plasticity and simultaneously on excitatory and inhibitory neurons. M-channels are voltage-gated potassium channels that play a crucial role in regulating neuronal excitability and plasticity. In cultured hippocampal excitatory neurons, we previously showed that chronic exposure to the M-channel blocker XE991 leads to adaptative compensations, thereby triggering at different timescales intrinsic and synaptic homeostatic plasticity. This plastic adaptation barely occurs in hippocampal inhibitory neurons. In this study, we examined whether this homeostatic plasticity induced by M-channel inhibition was bidirectional by investigating the acute and chronic effects of the M-channel opener retigabine on hippocampal neuronal excitability. Acute retigabine exposure decreased excitability in both excitatory and inhibitory neurons. Chronic retigabine treatment triggered in excitatory neurons homeostatic adaptation of the threshold current and spontaneous firing rate at a time scale of 4–24 h. These plastic changes were accompanied by a substantial decrease in the M-current density and by a small, though significant, proximal relocation of Kv7.3-FGF14 segment along the axon initial segment. Thus, bidirectional homeostatic changes were observed in excitatory neurons though not symmetric in kinetics and mechanisms. Contrastingly, in inhibitory neurons, the compensatory changes in intrinsic excitability barely occurred after 48 h, while no homeostatic normalization of the spontaneous firing rate was observed. Our results indicate that excitatory and inhibitory hippocampal neurons differ in their adaptation to chronic alterations in neuronal excitability induced by M-channel bidirectional modulation.
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16
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Dubes S, Soula A, Benquet S, Tessier B, Poujol C, Favereaux A, Thoumine O, Letellier M. miR
‐124‐dependent tagging of synapses by synaptopodin enables input‐specific homeostatic plasticity. EMBO J 2022; 41:e109012. [PMID: 35875872 PMCID: PMC9574720 DOI: 10.15252/embj.2021109012] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 06/11/2022] [Accepted: 06/27/2022] [Indexed: 12/26/2022] Open
Abstract
Homeostatic synaptic plasticity is a process by which neurons adjust their synaptic strength to compensate for perturbations in neuronal activity. Whether the highly diverse synapses on a neuron respond uniformly to the same perturbation remains unclear. Moreover, the molecular determinants that underlie synapse‐specific homeostatic synaptic plasticity are unknown. Here, we report a synaptic tagging mechanism in which the ability of individual synapses to increase their strength in response to activity deprivation depends on the local expression of the spine‐apparatus protein synaptopodin under the regulation of miR‐124. Using genetic manipulations to alter synaptopodin expression or regulation by miR‐124, we show that synaptopodin behaves as a “postsynaptic tag” whose translation is derepressed in a subpopulation of synapses and allows for nonuniform homeostatic strengthening and synaptic AMPA receptor stabilization. By genetically silencing individual connections in pairs of neurons, we demonstrate that this process operates in an input‐specific manner. Overall, our study shifts the current view that homeostatic synaptic plasticity affects all synapses uniformly to a more complex paradigm where the ability of individual synapses to undergo homeostatic changes depends on their own functional and biochemical state.
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Affiliation(s)
- Sandra Dubes
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Anaïs Soula
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Sébastien Benquet
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Béatrice Tessier
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Christel Poujol
- University of Bordeaux CNRS INSERM Bordeaux Imaging Center BIC UMS 3420, US 4 Bordeaux France
| | - Alexandre Favereaux
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Olivier Thoumine
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
| | - Mathieu Letellier
- University of Bordeaux CNRS Interdisciplinary Institute for Neuroscience UMR 5297 Bordeaux France
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17
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Inactivity and Ca 2+ signaling regulate synaptic compensation in motoneurons following hibernation in American bullfrogs. Sci Rep 2022; 12:11610. [PMID: 35803955 PMCID: PMC9270477 DOI: 10.1038/s41598-022-15525-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 06/24/2022] [Indexed: 11/24/2022] Open
Abstract
Neural networks tune synaptic and cellular properties to produce stable activity. One form of homeostatic regulation involves scaling the strength of synapses up or down in a global and multiplicative manner to oppose activity disturbances. In American bullfrogs, excitatory synapses scale up to regulate breathing motor function after inactivity in hibernation, connecting homeostatic compensation to motor behavior. In traditional models of homeostatic synaptic plasticity, inactivity is thought to increase synaptic strength via mechanisms that involve reduced Ca2+ influx through voltage-gated channels. Therefore, we tested whether pharmacological inactivity and inhibition of voltage-gated Ca2+ channels are sufficient to drive synaptic compensation in this system. For this, we chronically exposed ex vivo brainstem preparations containing the intact respiratory network to tetrodotoxin (TTX) to stop activity and nimodipine to block L-type Ca2+ channels. We show that hibernation and TTX similarly increased motoneuron synaptic strength and that hibernation occluded the response to TTX. In contrast, inhibiting L-type Ca2+ channels did not upregulate synaptic strength but disrupted the apparent multiplicative scaling of synaptic compensation typically observed in response to hibernation. Thus, inactivity drives up synaptic strength through mechanisms that do not rely on reduced L-type channel function, while Ca2+ signaling associated with the hibernation environment independently regulates the balance of synaptic weights. Altogether, these results point to multiple feedback signals for shaping synaptic compensation that gives rise to proper network function during environmental challenges in vivo.
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18
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Sun SY, Li XW, Cao R, Zhao Y, Sheng N, Tang AH. Correlative Assembly of Subsynaptic Nanoscale Organizations During Development. Front Synaptic Neurosci 2022; 14:748184. [PMID: 35685244 PMCID: PMC9171000 DOI: 10.3389/fnsyn.2022.748184] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 03/11/2022] [Indexed: 11/17/2022] Open
Abstract
Nanoscale organization of presynaptic proteins determines the sites of transmitter release, and its alignment with assemblies of postsynaptic receptors through nanocolumns is suggested to optimize the efficiency of synaptic transmission. However, it remains unknown how these nano-organizations are formed during development. In this study, we used super-resolution stochastic optical reconstruction microscopy (STORM) imaging technique to systematically analyze the evolvement of subsynaptic organization of three key synaptic proteins, namely, RIM1/2, GluA1, and PSD-95, during synapse maturation in cultured hippocampal neurons. We found that volumes of synaptic clusters and their subsynaptic heterogeneity increase as synapses get matured. Synapse sizes of presynaptic and postsynaptic compartments correlated well at all stages, while only more mature synapses demonstrated a significant correlation between presynaptic and postsynaptic nano-organizations. After a long incubation with an inhibitor of action potentials or AMPA receptors, both presynaptic and postsynaptic compartments showed increased synaptic cluster volume and subsynaptic heterogeneity; however, the trans-synaptic alignment was intact. Together, our results characterize the evolvement of subsynaptic protein architectures during development and demonstrate that the nanocolumn is organized more likely by an intrinsic mechanism and independent of synaptic activities.
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Affiliation(s)
- Shi-Yan Sun
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
| | - Xiao-Wei Li
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Ran Cao
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
| | - Yang Zhao
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- State Key Laboratory of Genetic Resources and Evolution in Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Nengyin Sheng
- State Key Laboratory of Genetic Resources and Evolution in Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
| | - Ai-Hui Tang
- Chinese Academy of Sciences (CAS) Key Laboratory of Brain Function and Disease, Ministry of Education Key Laboratory for Membrane-less Organelles and Cellular Dynamics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, China
- Institute of Artificial Intelligence, Hefei Comprehensive National Science Center, Hefei, China
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19
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Vergara P, Pino G, Vera J, Arancibia F, Sanhueza M. Heterogeneous CaMKII-Dependent Synaptic Compensations in CA1 Pyramidal Neurons From Acute Hippocampal Slices. Front Cell Neurosci 2022; 16:821088. [PMID: 35431809 PMCID: PMC9005847 DOI: 10.3389/fncel.2022.821088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Prolonged changes in neural activity trigger homeostatic synaptic plasticity (HSP) allowing neuronal networks to operate within functional ranges. Cell-wide or input-specific adaptations can be induced by pharmacological or genetic manipulations of activity, and by sensory deprivation. Reactive functional changes caused by deafferentation may partially share mechanisms with HSP. Acute hippocampal slices are a suitable model to investigate relatively rapid (hours) modifications occurring after denervation and explore the underlying mechanisms. As during slicing many afferents are cut, we conducted whole-cell recordings of miniature excitatory postsynaptic currents (mEPSCs) in CA1 pyramidal neurons to evaluate changes over the following 12 h. As Schaffer collaterals constitute a major glutamatergic input to these neurons, we also dissected CA3. We observed an average increment in mEPSCs amplitude and a decrease in decay time, suggesting synaptic AMPA receptor upregulation and subunit content modifications. Sorting mEPSC by rise time, a correlate of synapse location along dendrites, revealed amplitude raises at two separate domains. A specific frequency increase was observed in the same domains and was accompanied by a global, unspecific raise. Amplitude and frequency increments were lower at sites initially more active, consistent with local compensatory processes. Transient preincubation with a specific Ca2+/calmodulin-dependent kinase II (CaMKII) inhibitor either blocked or occluded amplitude and frequency upregulation in different synapse populations. Results are consistent with the concurrent development of different known CaMKII-dependent HSP processes. Our observations support that deafferentation causes rapid and diverse compensations resembling classical slow forms of adaptation to inactivity. These results may contribute to understand fast-developing homeostatic or pathological events after brain injury.
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20
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Wenner PA, Pekala D. Homeostatic Regulation of Motoneuron Properties in Development. ADVANCES IN NEUROBIOLOGY 2022; 28:87-107. [PMID: 36066822 DOI: 10.1007/978-3-031-07167-6_4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Homeostatic plasticity represents a set of compensatory mechanisms that are engaged following a perturbation to some feature of neuronal or network function. Homeostatic mechanisms are most robustly expressed during development, a period that is replete with various perturbations such as increased cell size and the addition/removal of synaptic connections. In this review we look at numerous studies that have advanced our understanding of homeostatic plasticity by taking advantage of the accessibility of developing motoneurons. We discuss the homeostatic regulation of embryonic movements in the living chick embryo and describe the spinal compensatory mechanisms that act to recover these movements (homeostatic intrinsic plasticity) or stabilize synaptic strength (synaptic scaling). We describe the expression and triggering mechanisms of these forms of homeostatic plasticity and thereby gain an understanding of their roles in the motor system. We then illustrate how these findings can be extended to studies of developing motoneurons in other systems including the rodents, zebrafish, and fly. Furthermore, studies in developing drosophila have been critical in identifying some of the molecular signaling cascades and expression mechanisms that underlie homeostatic intrinsic membrane excitability. This powerful model organism has also been used to study a presynaptic form of homeostatic plasticity where increases or decreases in synaptic transmission are associated with compensatory changes in probability of release at the neuromuscular junction. Further, we describe studies that demonstrate homeostatic adjustments of ion channel expression following perturbations to other kinds of ion channels. Finally, we discuss work in xenopus that shows a homeostatic regulation of neurotransmitter phenotype in developing motoneurons following activity perturbations. Together, this work illustrates the importance of developing motoneurons in elucidating the mechanisms and roles of homeostatic plasticity.
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Affiliation(s)
- Peter A Wenner
- Department of Cell Biology, Whitehead Biomedical Research Building, Emory University School of Medicine, Atlanta, GA, USA.
| | - Dobromila Pekala
- Department of Cell Biology, Whitehead Biomedical Research Building, Emory University School of Medicine, Atlanta, GA, USA
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21
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Moulin TC, Rayêe D, Schiöth HB. Dendritic spine density changes and homeostatic synaptic scaling: a meta-analysis of animal studies. Neural Regen Res 2022; 17:20-24. [PMID: 34100421 PMCID: PMC8451564 DOI: 10.4103/1673-5374.314283] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Mechanisms of homeostatic plasticity promote compensatory changes of cellular excitability in response to chronic changes in the network activity. This type of plasticity is essential for the maintenance of brain circuits and is involved in the regulation of neural regeneration and the progress of neurodegenerative disorders. One of the most studied homeostatic processes is synaptic scaling, where global synaptic adjustments take place to restore the neuronal firing rate to a physiological range by the modulation of synaptic receptors, neurotransmitters, and morphology. However, despite the comprehensive literature on the electrophysiological properties of homeostatic scaling, less is known about the structural adjustments that occur in the synapses and dendritic tree. In this study, we performed a meta-analysis of articles investigating the effects of chronic network excitation (synaptic downscaling) or inhibition (synaptic upscaling) on the dendritic spine density of neurons. Our results indicate that spine density is consistently reduced after protocols that induce synaptic scaling, independent of the intervention type. Then, we discuss the implication of our findings to the current knowledge on the morphological changes induced by homeostatic plasticity.
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Affiliation(s)
- Thiago C Moulin
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden; Institute of Medical Biochemistry, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Danielle Rayêe
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil; Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, NY, USA
| | - Helgi B Schiöth
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden; Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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22
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Thapliyal S, Arendt KL, Lau AG, Chen L. Retinoic acid-gated BDNF synthesis in neuronal dendrites drives presynaptic homeostatic plasticity. eLife 2022; 11:79863. [PMID: 36515276 PMCID: PMC9797192 DOI: 10.7554/elife.79863] [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: 04/29/2022] [Accepted: 11/23/2022] [Indexed: 12/15/2022] Open
Abstract
Homeostatic synaptic plasticity is a non-Hebbian synaptic mechanism that adjusts synaptic strength to maintain network stability while achieving optimal information processing. Among the molecular mediators shown to regulate this form of plasticity, synaptic signaling through retinoic acid (RA) and its receptor, RARα, has been shown to be critically involved in the homeostatic adjustment of synaptic transmission in both hippocampus and sensory cortices. In this study, we explore the molecular mechanism through which postsynaptic RA and RARα regulates presynaptic neurotransmitter release during prolonged synaptic inactivity at mouse glutamatertic synapses. We show that RARα binds to a subset of dendritically sorted brain-derived neurotrophic factor (Bdnf) mRNA splice isoforms and represses their translation. The RA-mediated translational de-repression of postsynaptic BDNF results in the retrograde activation of presynaptic tropomyosin receptor kinase B (TrkB) receptors, facilitating presynaptic homeostatic compensation through enhanced presynaptic release. Together, our study illustrates an RA-mediated retrograde synaptic signaling pathway through which postsynaptic protein synthesis during synaptic inactivity drives compensatory changes at the presynaptic site.
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Affiliation(s)
- Shruti Thapliyal
- Departments of Neurosurgery, Neuropsychiatry and Behavioral Sciences, Stanford University School of MedicineStanfordUnited States
| | - Kristin L Arendt
- Departments of Neurosurgery, Neuropsychiatry and Behavioral Sciences, Stanford University School of MedicineStanfordUnited States
| | - Anthony G Lau
- Departments of Neurosurgery, Neuropsychiatry and Behavioral Sciences, Stanford University School of MedicineStanfordUnited States
| | - Lu Chen
- Departments of Neurosurgery, Neuropsychiatry and Behavioral Sciences, Stanford University School of MedicineStanfordUnited States
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23
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Zbili M, Rama S, Benitez MJ, Fronzaroli-Molinieres L, Bialowas A, Boumedine-Guignon N, Garrido JJ, Debanne D. Homeostatic regulation of axonal Kv1.1 channels accounts for both synaptic and intrinsic modifications in the hippocampal CA3 circuit. Proc Natl Acad Sci U S A 2021; 118:e2110601118. [PMID: 34799447 PMCID: PMC8617510 DOI: 10.1073/pnas.2110601118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2021] [Indexed: 11/18/2022] Open
Abstract
Homeostatic plasticity of intrinsic excitability goes hand in hand with homeostatic plasticity of synaptic transmission. However, the mechanisms linking the two forms of homeostatic regulation have not been identified so far. Using electrophysiological, imaging, and immunohistochemical techniques, we show here that blockade of excitatory synaptic receptors for 2 to 3 d induces an up-regulation of both synaptic transmission at CA3-CA3 connections and intrinsic excitability of CA3 pyramidal neurons. Intrinsic plasticity was found to be mediated by a reduction of Kv1.1 channel density at the axon initial segment. In activity-deprived circuits, CA3-CA3 synapses were found to express a high release probability, an insensitivity to dendrotoxin, and a lack of depolarization-induced presynaptic facilitation, indicating a reduction in presynaptic Kv1.1 function. Further support for the down-regulation of axonal Kv1.1 channels in activity-deprived neurons was the broadening of action potentials measured in the axon. We conclude that regulation of the axonal Kv1.1 channel constitutes a major mechanism linking intrinsic excitability and synaptic strength that accounts for the functional synergy existing between homeostatic regulation of intrinsic excitability and synaptic transmission.
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Affiliation(s)
- Mickaël Zbili
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| | - Sylvain Rama
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| | - Maria-José Benitez
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), Madrid 28002, Spain
- Departamento de Química Física Aplicada, Universidad Autónoma de Madrid, Madrid 28049, Spain
| | - Laure Fronzaroli-Molinieres
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| | - Andrzej Bialowas
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| | - Norah Boumedine-Guignon
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France
| | - Juan José Garrido
- Instituto Cajal, Consejo Superior de Investigaciones Cientificas (CSIC), Madrid 28002, Spain
| | - Dominique Debanne
- Unité de Neurobiologie des canaux Ioniques et de la Synapse (UNIS), UMR_S 1072, INSERM, Aix-Marseille Université, Marseille 13015, France;
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24
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Kleidonas D, Vlachos A. Scavenging Tumor Necrosis Factor α Does Not Affect Inhibition of Dentate Granule Cells Following In Vitro Entorhinal Cortex Lesion. Cells 2021; 10:3232. [PMID: 34831454 PMCID: PMC8618320 DOI: 10.3390/cells10113232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/31/2021] [Accepted: 11/16/2021] [Indexed: 11/18/2022] Open
Abstract
Neurons that lose part of their afferent input remodel their synaptic connections. While cellular and molecular mechanisms of denervation-induced changes in excitatory neurotransmission have been identified, little is known about the signaling pathways that control inhibition in denervated networks. In this study, we used mouse entorhino-hippocampal tissue cultures of both sexes to study the role of the pro-inflammatory cytokine tumor necrosis factor α (TNFα) in denervation-induced plasticity of inhibitory neurotransmission. In line with our previous findings in vitro, an entorhinal cortex lesion triggered a compensatory increase in the excitatory synaptic strength of partially denervated dentate granule cells. Inhibitory synaptic strength was not changed 3 days after the lesion. These functional changes were accompanied by a recruitment of microglia in the denervated hippocampus, and experiments in tissue cultures prepared from TNF-reporter mice [C57BL/6-Tg(TNFa-eGFP)] showed increased TNFα expression in the denervated zone. However, inhibitory neurotransmission was not affected by scavenging TNFα with a soluble TNF receptor. In turn, a decrease in inhibition, i.e., decreased frequencies of miniature inhibitory postsynaptic currents, was observed in denervated dentate granule cells of microglia-depleted tissue cultures. We conclude from these results that activated microglia maintain the inhibition of denervated dentate granule cells and that TNFα is not required for the maintenance of inhibition after denervation.
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Affiliation(s)
- Dimitrios Kleidonas
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany;
- Spemann Graduate School of Biology and Medicine (SGBM), University of Freiburg, 79104 Freiburg, Germany
- Faculty of Biology, University of Freiburg, 79104 Freiburg, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany;
- Center Brain Links Brain Tools, University of Freiburg, 79110 Freiburg, Germany
- Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
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25
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Srinivasan B, Samaddar S, Mylavarapu SVS, Clement JP, Banerjee S. Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling. PLoS Biol 2021; 19:e3001432. [PMID: 34813590 PMCID: PMC8610276 DOI: 10.1371/journal.pbio.3001432] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/30/2021] [Indexed: 01/17/2023] Open
Abstract
Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3' UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity.
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Affiliation(s)
| | | | | | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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26
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Sanderson JL, Freund RK, Gorski JA, Dell'Acqua ML. β-Amyloid disruption of LTP/LTD balance is mediated by AKAP150-anchored PKA and Calcineurin regulation of Ca 2+-permeable AMPA receptors. Cell Rep 2021; 37:109786. [PMID: 34610314 PMCID: PMC8530450 DOI: 10.1016/j.celrep.2021.109786] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 07/02/2021] [Accepted: 09/10/2021] [Indexed: 01/28/2023] Open
Abstract
Regulated insertion and removal of postsynaptic AMPA glutamate receptors (AMPARs) mediates hippocampal long-term potentiation (LTP) and long-term depression (LTD) synaptic plasticity underlying learning and memory. In Alzheimer’s disease β-amyloid (Aβ) oligomers may impair learning and memory by altering AMPAR trafficking and LTP/LTD balance. Importantly, Ca2+-permeable AMPARs (CP-AMPARs) assembled from GluA1 subunits are excluded from hippocampal synapses basally but can be recruited rapidly during LTP and LTD to modify synaptic strength and signaling. By employing mouse knockin mutations that disrupt anchoring of the kinase PKA or phosphatase Calcineurin (CaN) to the postsynaptic scaffold protein AKAP150, we find that local AKAP-PKA signaling is required for CP-AMPAR recruitment, which can facilitate LTP but also, paradoxically, prime synapses for Aβ impairment of LTP mediated by local AKAP-CaN LTD signaling that promotes subsequent CP-AMPAR removal. These findings highlight the importance of PKA/CaN signaling balance and CP-AMPARs in normal plasticity and aberrant plasticity linked to disease. In Alzheimer’s disease, Aβ oligomers disrupt hippocampal neuronal plasticity and cognition. Sanderson et al. show how the postsynaptic scaffold protein AKAP150 coordinates PKA and Calcineurin regulation of Ca2+-permeable AMPA-type glutamate receptors to mediate disruption of synaptic plasticity by Aβ oligomers.
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Affiliation(s)
- Jennifer L Sanderson
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Ronald K Freund
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Jessica A Gorski
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Mark L Dell'Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO 80045, USA; University of Colorado Alzheimer's and Cognition Center, Anschutz Medical Campus, Aurora, CO 80045, USA; Linda Crnic Institute for Down Syndrome, Anschutz Medical Campus, Aurora, CO 80045, USA.
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27
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Murray CH, Gaulden AD, Kawa AB, Milovanovic M, Caccamise AJ, Funke JR, Patel S, Wolf ME. CaMKII Modulates Diacylglycerol Lipase-α Activity in the Rat Nucleus Accumbens after Incubation of Cocaine Craving. eNeuro 2021; 8:ENEURO.0220-21.2021. [PMID: 34544759 PMCID: PMC8503962 DOI: 10.1523/eneuro.0220-21.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 08/10/2021] [Accepted: 08/19/2021] [Indexed: 01/04/2023] Open
Abstract
Relapse is a major challenge to the treatment of substance use disorders. A progressive increase in cue-induced drug craving, termed incubation of craving, is observed after withdrawal from multiple drugs of abuse in humans and rodents. Incubation of cocaine craving involves the strengthening of excitatory synapses onto nucleus accumbens (NAc) medium spiny neurons via postsynaptic accumulation of high-conductance Ca2+-permeable AMPA receptors. This enhances reactivity to drug-associated cues and is required for the expression of incubation. Additionally, incubation of cocaine craving is associated with loss of the synaptic depression normally triggered by stimulation of metabotropic glutamate receptor 5 (mGlu5), leading to endocannabinoid production, and expressed presynaptically via cannabinoid receptor 1 activation. Previous studies have found alterations in mGlu5 and Homer proteins associated with the loss of this synaptic depression. Here we conducted coimmunoprecipitation studies to investigate associations of diacylglycerol lipase-α (DGL), which catalyzes formation of the endocannabinoid 2-arachidonylglycerol (2-AG), with mGlu5 and Homer proteins. Although these interactions were unchanged in the NAc core at incubation-relevant withdrawal times, the association of DGL with total and phosphorylated Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) and CaMKIIβ was increased. This would be predicted, based on other studies, to inhibit DGL activity and therefore 2-AG production. This was confirmed by measuring DGL enzymatic activity. However, the magnitude of DGL inhibition did not correlate with the magnitude of incubation of craving for individual rats. These results suggest that CaMKII contributes to the loss of mGlu5-dependent synaptic depression after incubation, but the functional significance of this loss remains unclear.
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Affiliation(s)
- Conor H Murray
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064-3095
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Andrew D Gaulden
- Department of Psychiatry, Vanderbilt University, Nashville, Tennessee 37240
| | - Alex B Kawa
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Mike Milovanovic
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064-3095
| | - Aaron J Caccamise
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064-3095
| | - Jonathan R Funke
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239-3098
| | - Sachin Patel
- Department of Psychiatry, Vanderbilt University, Nashville, Tennessee 37240
| | - Marina E Wolf
- Department of Neuroscience, Chicago Medical School, Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064-3095
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, Oregon 97239-3098
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28
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Desch K, Langer JD, Schuman EM. Dynamic bi-directional phosphorylation events associated with the reciprocal regulation of synapses during homeostatic up- and down-scaling. Cell Rep 2021; 36:109583. [PMID: 34433048 PMCID: PMC8411114 DOI: 10.1016/j.celrep.2021.109583] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/15/2021] [Accepted: 07/29/2021] [Indexed: 01/17/2023] Open
Abstract
Homeostatic synaptic scaling allows for bi-directional adjustment of the strength of synaptic connections in response to changes in their input. Protein phosphorylation modulates many neuronal processes, but it has not been studied on a global scale during synaptic scaling. Here, we use liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses to measure changes in the phosphoproteome in response to up- or down-scaling in cultured cortical neurons over minutes to 24 h. Of ~45,000 phosphorylation events, ~3,300 (associated with 1,285 phosphoproteins) are regulated by homeostatic scaling. Activity-sensitive phosphoproteins are predominantly located at synapses and involved in cytoskeletal reorganization. We identify many early phosphorylation events that could serve as sensors for the activity offset as well as late and/or persistent phosphoregulation that could represent effector mechanisms driving the homeostatic response. Much of the persistent phosphorylation is reciprocally regulated by up- or down-scaling, suggesting that mechanisms underlying these two poles of synaptic regulation make use of a common signaling axis. Global proteome and phosphoproteome dynamics following homeostatic synaptic scaling Approximately 3,300 activity-sensitive, synapse-associated phospho-events Persistent signaling of ~25% of initial phospho-events (min to 24 h) Persistent and reciprocal phosphoregulation links synaptic up- and down-scaling
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Affiliation(s)
- Kristina Desch
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany.
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany.
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29
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Wu Y, Lv X, Wang H, Qian K, Ding J, Wang J, Hua S, Sun T, Zhou Y, Yu L, Qiu S. Adaptor protein APPL1 links neuronal activity to chromatin remodeling in cultured hippocampal neurons. J Mol Cell Biol 2021; 13:335-346. [PMID: 33104190 PMCID: PMC8373263 DOI: 10.1093/jmcb/mjaa058] [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: 04/06/2020] [Revised: 07/29/2020] [Accepted: 08/25/2020] [Indexed: 11/15/2022] Open
Abstract
Local signaling events at synapses or axon terminals are communicated to the nucleus to elicit transcriptional responses, and thereby translate information about the external environment into internal neuronal representations. This retrograde signaling is critical to dendritic growth, synapse development, and neuronal plasticity. Here, we demonstrate that neuronal activity induces retrograde translocation and nuclear accumulation of endosomal adaptor APPL1. Disrupting the interaction of APPL1 with Importin α1 abolishes nuclear accumulation of APPL1, which in turn decreases the levels of histone acetylation. We further demonstrate that retrograde translocation of APPL1 is required for the regulation of gene transcription and then maintenance of hippocampal late-phase long-term potentiation. Thus, these results illustrate an APPL1-mediated pathway that contributes to the modulation of synaptic plasticity via coupling neuronal activity with chromatin remodeling.
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Affiliation(s)
- Yu Wu
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xinyou Lv
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Haiting Wang
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Kai Qian
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jinjun Ding
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Jiejie Wang
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shushan Hua
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Tiancheng Sun
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Yiting Zhou
- Department of Biochemistry, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Orthopaedic Surgery, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Lina Yu
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Shuang Qiu
- Department of Neurobiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,Department of Anesthesiology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China.,NHC and CAMS Key Laboratory of Medical Neurobiology, MOE Frontier Science Center for Brain Research and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou 310058, China
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30
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Zhou Z, He G, Zhang X, Lv X, Zhang X, Liu A, Xia S, Xie H, Dang R, Han L, Qi J, Meng Y, Yu S, Xie W, Jia Z. NGPF2 triggers synaptic scaling up through ALK-LIMK-cofilin-mediated mechanisms. Cell Rep 2021; 36:109515. [PMID: 34407403 DOI: 10.1016/j.celrep.2021.109515] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 03/26/2021] [Accepted: 07/21/2021] [Indexed: 02/07/2023] Open
Abstract
Synaptic scaling is an extensively studied form of homeostatic plasticity critically involved in various brain functions. Although it is accepted that synaptic scaling is expressed through the postsynaptic accumulation of AMPA receptors (AMPARs), the induction mechanism remains elusive. In this study, we show that TTX treatment induces rapid but transient release of the neurite growth-promoting factor 2 (NGPF2), and this release is necessary and sufficient for TTX-induced scaling up. In addition, we show that inhibition of the anaplastic lymphoma kinase (ALK)-LIMK-cofilin signaling pathway blocks TTX- and NGPF2-induced synaptic scaling up. Furthermore, we show that TTX-induced release of NGPF2 is protein synthesis dependent and requires fragile X mental retardation protein 1 (FMRP1). These results indicate that activity blockade induces NGPF2 synthesis and release to trigger synaptic scaling up through LIMK-cofilin-dependent actin reorganization, spine enlargement, and stabilization of AMPARs at the synapse.
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Affiliation(s)
- Zikai Zhou
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; Zhongshan Institute for Drug Discovery, the Institutes of Drug Discovery and Development, Chinese Academy of Sciences, Zhongshan, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China.
| | - Guiqin He
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China; School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Xiaoyun Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai 201203, China; Zhongshan Institute for Drug Discovery, the Institutes of Drug Discovery and Development, Chinese Academy of Sciences, Zhongshan, China
| | - Xin Lv
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiaolin Zhang
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - An Liu
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Shuting Xia
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China; Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Hao Xie
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Rui Dang
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Lifang Han
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Junxia Qi
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Yanghong Meng
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada
| | - Shunying Yu
- Shanghai Key Laboratory of Psychotic Disorders, Shanghai Mental Health Center, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wei Xie
- School of Life Science and Technology, Southeast University, 2 Sipailou Road, Nanjing 210096, China
| | - Zhengping Jia
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Avenue, Toronto, ON M5G 1X8, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, ON M5S 1A8, Canada.
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31
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Ge Y, Wang YT. GluA1-homomeric AMPA receptor in synaptic plasticity and neurological diseases. Neuropharmacology 2021; 197:108708. [PMID: 34274350 DOI: 10.1016/j.neuropharm.2021.108708] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/28/2021] [Accepted: 07/08/2021] [Indexed: 11/17/2022]
Abstract
Synaptic transmission is one of the fundamental processes that all brain functions are based on. Changes in the strength of synaptic transmission among neurons are crucial for information processing in the central nervous system. The α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid subtype of ionotropic glutamate receptors (AMPARs) mediate the majority of the fast excitatory synaptic transmission in the mammalian brain. Rapid trafficking of AMPARs in and out of the postsynaptic membrane is proposed to be a major mechanism for synaptic plasticity, and learning and memory. Defects in the regulated AMPAR trafficking have been shown to be involved in the pathogenesis of certain psychiatric and neurodegenerative diseases. Studies accumulated in the past 30 years have provided a detailed molecular insight on how the trafficking of AMPARs is modulated in a subunit-specific manner. In particular, emerging evidence supports that the regulated expression and trafficking of Ca2+-permeable, GluA1-homomeric subtype of AMPARs mediates diverse types of synaptic plasticity, thereby playing critical roles in brain function and dysfunction. In this review, we will discuss the current knowledge of AMPAR subunit-specific trafficking, with a particular emphasis on the involvement of GluA1-homomeric receptor trafficking in synaptic plasticity and brain disorders.
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Affiliation(s)
- Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada; Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC, V6T 2B5, Canada
| | - Yu Tian Wang
- Djavad Mowafaghian Centre for Brain Health and Department of Medicine, University of British Columbia, Vancouver, BC, V6T 2B5, Canada.
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32
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Ruggiero A, Katsenelson M, Slutsky I. Mitochondria: new players in homeostatic regulation of firing rate set points. Trends Neurosci 2021; 44:605-618. [PMID: 33865626 DOI: 10.1016/j.tins.2021.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 02/10/2021] [Accepted: 03/11/2021] [Indexed: 10/21/2022]
Abstract
Neural circuit functions are stabilized by homeostatic processes at long timescales in response to changes in behavioral states, experience, and learning. However, it remains unclear which specific physiological variables are being stabilized and which cellular or neural network components compose the homeostatic machinery. At this point, most evidence suggests that the distribution of firing rates among neurons in a neuronal circuit is the key variable that is maintained around a set-point value in a process called 'firing rate homeostasis.' Here, we review recent findings that implicate mitochondria as central players in mediating firing rate homeostasis. While mitochondria are known to regulate neuronal variables such as synaptic vesicle release or intracellular calcium concentration, the mitochondrial signaling pathways that are essential for firing rate homeostasis remain largely unknown. We used basic concepts of control theory to build a framework for classifying possible components of the homeostatic machinery that stabilizes firing rate, and we particularly emphasize the potential role of sleep and wakefulness in this homeostatic process. This framework may facilitate the identification of new homeostatic pathways whose malfunctions drive instability of neural circuits in distinct brain disorders.
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Affiliation(s)
- Antonella Ruggiero
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Maxim Katsenelson
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel
| | - Inna Slutsky
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel.
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33
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Changes in Presynaptic Gene Expression during Homeostatic Compensation at a Central Synapse. J Neurosci 2021; 41:3054-3067. [PMID: 33608385 PMCID: PMC8026347 DOI: 10.1523/jneurosci.2979-20.2021] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 01/27/2021] [Accepted: 01/28/2021] [Indexed: 12/02/2022] Open
Abstract
Homeostatic matching of pre- and postsynaptic function has been observed in many species and neural structures, but whether transcriptional changes contribute to this form of trans-synaptic coordination remains unknown. To identify genes whose expression is altered in presynaptic neurons as a result of perturbing postsynaptic excitability, we applied a transcriptomics-friendly, temperature-inducible Kir2.1-based activity clamp at the first synaptic relay of the Drosophila olfactory system, a central synapse known to exhibit trans-synaptic homeostatic matching. Twelve hours after adult-onset suppression of activity in postsynaptic antennal lobe projection neurons of males and females, we detected changes in the expression of many genes in the third antennal segment, which houses the somata of presynaptic olfactory receptor neurons. These changes affected genes with roles in synaptic vesicle release and synaptic remodeling, including several implicated in homeostatic plasticity at the neuromuscular junction. At 48 h and beyond, the transcriptional landscape tilted toward protein synthesis, folding, and degradation; energy metabolism; and cellular stress defenses, indicating that the system had been pushed to its homeostatic limits. Our analysis suggests that similar homeostatic machinery operates at peripheral and central synapses and identifies many of its components. The presynaptic transcriptional response to genetically targeted postsynaptic perturbations could be exploited for the construction of novel connectivity tracing tools. SIGNIFICANCE STATEMENT Homeostatic feedback mechanisms adjust intrinsic and synaptic properties of neurons to keep their average activity levels constant. We show that, at a central synapse in the fruit fly brain, these mechanisms include changes in presynaptic gene expression that are instructed by an abrupt loss of postsynaptic excitability. The trans-synaptically regulated genes have roles in synaptic vesicle release and synapse remodeling; protein synthesis, folding, and degradation; and energy metabolism. Our study establishes a role for transcriptional changes in homeostatic synaptic plasticity, points to mechanistic commonalities between peripheral and central synapses, and potentially opens new opportunities for the development of connectivity-based gene expression systems.
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34
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Bissen D, Kracht MK, Foss F, Hofmann J, Acker-Palmer A. EphrinB2 and GRIP1 stabilize mushroom spines during denervation-induced homeostatic plasticity. Cell Rep 2021; 34:108923. [PMID: 33789115 PMCID: PMC8028307 DOI: 10.1016/j.celrep.2021.108923] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 12/20/2020] [Accepted: 03/09/2021] [Indexed: 12/03/2022] Open
Abstract
Despite decades of work, much remains elusive about molecular events at the interplay between physiological and structural changes underlying neuronal plasticity. Here, we combined repetitive live imaging and expansion microscopy in organotypic brain slice cultures to quantitatively characterize the dynamic changes of the intracellular versus surface pools of GluA2-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) across the different dendritic spine types and the shaft during hippocampal homeostatic plasticity. Mechanistically, we identify ephrinB2 and glutamate receptor interacting protein (GRIP) 1 as mediating AMPAR relocation to the mushroom spine surface following lesion-induced denervation. Moreover, stimulation with the ephrinB2 specific receptor EphB4 not only prevents the lesion-induced disappearance of mushroom spines but is also sufficient to shift AMPARs to the surface and rescue spine recovery in a GRIP1 dominant-negative background. Thus, our results unravel a crucial role for ephrinB2 during homeostatic plasticity and identify a potential pharmacological target to improve dendritic spine plasticity upon injury.
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Affiliation(s)
- Diane Bissen
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany; Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438 Frankfurt am Main, Germany
| | - Maximilian Ken Kracht
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Franziska Foss
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Jan Hofmann
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany; Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438 Frankfurt am Main, Germany; Cardio-Pulmonary Institute (CPI), Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany.
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35
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Rey S, Marra V, Smith C, Staras K. Nanoscale Remodeling of Functional Synaptic Vesicle Pools in Hebbian Plasticity. Cell Rep 2021; 30:2006-2017.e3. [PMID: 32049027 PMCID: PMC7016504 DOI: 10.1016/j.celrep.2020.01.051] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 10/21/2019] [Accepted: 01/14/2020] [Indexed: 12/23/2022] Open
Abstract
Vesicle pool properties are known determinants of synaptic efficacy, but their potential role as modifiable substrates in forms of Hebbian plasticity is still unclear. Here, we investigate this using a nanoscale readout of functionally recycled vesicles in natively wired hippocampal CA3→CA1 circuits undergoing long-term potentiation (LTP). We show that the total recycled vesicle pool is larger after plasticity induction, with the smallest terminals exhibiting the greatest relative expansion. Changes in the spatial organization of vesicles accompany potentiation including a specific increase in the number of recycled vesicles at the active zone, consistent with an ultrastructural remodeling component of synaptic strengthening. The cAMP-PKA pathway activator, forskolin, selectively mimics some features of LTP-driven changes, suggesting that distinct and independent modules of regulation accompany plasticity expression. Our findings provide evidence for a presynaptic locus of LTP encoded in the number and arrangement of functionally recycled vesicles, with relevance for models of long-term plasticity storage.
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Affiliation(s)
- Stephanie Rey
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Vincenzo Marra
- Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester L1 7RH, United Kingdom
| | - Catherine Smith
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Kevin Staras
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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36
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Di Benedetto G, Iannucci LF, Surdo NC, Zanin S, Conca F, Grisan F, Gerbino A, Lefkimmiatis K. Compartmentalized Signaling in Aging and Neurodegeneration. Cells 2021; 10:464. [PMID: 33671541 PMCID: PMC7926881 DOI: 10.3390/cells10020464] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2020] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/12/2022] Open
Abstract
The cyclic AMP (cAMP) signalling cascade is necessary for cell homeostasis and plays important roles in many processes. This is particularly relevant during ageing and age-related diseases, where drastic changes, generally decreases, in cAMP levels have been associated with the progressive decline in overall cell function and, eventually, the loss of cellular integrity. The functional relevance of reduced cAMP is clearly supported by the finding that increases in cAMP levels can reverse some of the effects of ageing. Nevertheless, despite these observations, the molecular mechanisms underlying the dysregulation of cAMP signalling in ageing are not well understood. Compartmentalization is widely accepted as the modality through which cAMP achieves its functional specificity; therefore, it is important to understand whether and how this mechanism is affected during ageing and to define which is its contribution to this process. Several animal models demonstrate the importance of specific cAMP signalling components in ageing, however, how age-related changes in each of these elements affect the compartmentalization of the cAMP pathway is largely unknown. In this review, we explore the connection of single components of the cAMP signalling cascade to ageing and age-related diseases whilst elaborating the literature in the context of cAMP signalling compartmentalization.
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Affiliation(s)
- Giulietta Di Benedetto
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy;
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
| | - Liliana F. Iannucci
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Nicoletta C. Surdo
- Neuroscience Institute, National Research Council of Italy (CNR), 35121 Padova, Italy;
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
| | - Sofia Zanin
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
| | - Filippo Conca
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Biology, University of Padova, 35122 Padova, Italy
| | - Francesca Grisan
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Biology, University of Padova, 35122 Padova, Italy
| | - Andrea Gerbino
- Department of Biosciences, Biotechnology and Biopharmaceutics, University of Bari, 70121 Bari, Italy;
| | - Konstantinos Lefkimmiatis
- Veneto Institute of Molecular Medicine, Foundation for Advanced Biomedical Research, 35129 Padova, Italy; (L.F.I.); (S.Z.); (F.C.); (F.G.)
- Department of Molecular Medicine, University of Pavia, 27100 Pavia, Italy
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37
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Heir R, Stellwagen D. TNF-Mediated Homeostatic Synaptic Plasticity: From in vitro to in vivo Models. Front Cell Neurosci 2020; 14:565841. [PMID: 33192311 PMCID: PMC7556297 DOI: 10.3389/fncel.2020.565841] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 08/24/2020] [Indexed: 12/21/2022] Open
Abstract
Since it was first described almost 30 years ago, homeostatic synaptic plasticity (HSP) has been hypothesized to play a key role in maintaining neuronal circuit function in both developing and adult animals. While well characterized in vitro, determining the in vivo roles of this form of plasticity remains challenging. Since the discovery that the pro-inflammatory cytokine tumor necrosis factor-α (TNF-α) mediates some forms of HSP, it has been possible to probe some of the in vivo contribution of TNF-mediated HSP. Work from our lab and others has found roles for TNF-HSP in a variety of functions, including the developmental plasticity of sensory systems, models of drug addiction, and the response to psychiatric drugs.
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Affiliation(s)
- Renu Heir
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montréal, QC, Canada
| | - David Stellwagen
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Research Institute of the McGill University Health Center, Montréal, QC, Canada
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38
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Kavalali ET, Monteggia LM. Targeting Homeostatic Synaptic Plasticity for Treatment of Mood Disorders. Neuron 2020; 106:715-726. [PMID: 32497508 DOI: 10.1016/j.neuron.2020.05.015] [Citation(s) in RCA: 96] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/05/2020] [Accepted: 05/07/2020] [Indexed: 01/23/2023]
Abstract
Ketamine exerts rapid antidepressant action in depressed and treatment-resistant depressed patients within hours. At the same time, ketamine elicits a unique form of functional synaptic plasticity that shares several attributes and molecular mechanisms with well-characterized forms of homeostatic synaptic scaling. Lithium is a widely used mood stabilizer also proposed to act via synaptic scaling for its antimanic effects. Several studies to date have identified specific forms of homeostatic synaptic plasticity that are elicited by these drugs used to treat neuropsychiatric disorders. In the last two decades, extensive work on homeostatic synaptic plasticity mechanisms have shown that they diverge from classical synaptic plasticity mechanisms that process and store information and thus present a novel avenue for synaptic regulation with limited direct interference with cognitive processes. In this review, we discuss the intersection of the findings from neuropsychiatric treatments and homeostatic plasticity studies to highlight a potentially wider paradigm for treatment advance.
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Affiliation(s)
- Ege T Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA.
| | - Lisa M Monteggia
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240-7933, USA.
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39
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Bachmann C, Tetzlaff T, Duarte R, Morrison A. Firing rate homeostasis counteracts changes in stability of recurrent neural networks caused by synapse loss in Alzheimer's disease. PLoS Comput Biol 2020; 16:e1007790. [PMID: 32841234 PMCID: PMC7505475 DOI: 10.1371/journal.pcbi.1007790] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/21/2020] [Accepted: 03/17/2020] [Indexed: 11/19/2022] Open
Abstract
The impairment of cognitive function in Alzheimer's disease is clearly correlated to synapse loss. However, the mechanisms underlying this correlation are only poorly understood. Here, we investigate how the loss of excitatory synapses in sparsely connected random networks of spiking excitatory and inhibitory neurons alters their dynamical characteristics. Beyond the effects on the activity statistics, we find that the loss of excitatory synapses on excitatory neurons reduces the network's sensitivity to small perturbations. This decrease in sensitivity can be considered as an indication of a reduction of computational capacity. A full recovery of the network's dynamical characteristics and sensitivity can be achieved by firing rate homeostasis, here implemented by an up-scaling of the remaining excitatory-excitatory synapses. Mean-field analysis reveals that the stability of the linearised network dynamics is, in good approximation, uniquely determined by the firing rate, and thereby explains why firing rate homeostasis preserves not only the firing rate but also the network's sensitivity to small perturbations.
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Affiliation(s)
- Claudia Bachmann
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Tom Tetzlaff
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Renato Duarte
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Abigail Morrison
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
- Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
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40
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Carr KD. Modulatory Effects of Food Restriction on Brain and Behavioral Effects of Abused Drugs. Curr Pharm Des 2020; 26:2363-2371. [DOI: 10.2174/1381612826666200204141057] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Accepted: 11/19/2019] [Indexed: 12/14/2022]
Abstract
Energy homeostasis is achieved, in part, by metabolic signals that regulate the incentive motivating
effects of food and its cues, thereby driving or curtailing procurement and consumption. The neural underpinnings
of these regulated incentive effects have been identified as elements within the mesolimbic dopamine pathway.
A separate line of research has shown that most drugs with abuse liability increase dopamine transmission in
this same pathway and thereby reinforce self-administration. Consequently, one might expect shifts in energy
balance and metabolic signaling to impact drug abuse risk. Basic science studies have yielded numerous examples
of drug responses altered by diet manipulation. Considering the prevalence of weight loss dieting in Western
societies, and the anorexigenic effects of many abused drugs themselves, we have focused on the CNS and behavioral
effects of food restriction in rats. Food restriction has been shown to increase the reward magnitude of diverse
drugs of abuse, and these effects have been attributed to neuroadaptations in the dopamine-innervated nucleus
accumbens. The changes induced by food restriction include synaptic incorporation of calcium-permeable
AMPA receptors and increased signaling downstream of D1 dopamine receptor stimulation. Recent studies suggest
a mechanistic model in which concurrent stimulation of D1 and GluA2-lacking AMPA receptors enables
increased stimulus-induced trafficking of GluA1/GluA2 AMPARs into the postsynaptic density, thereby increasing
the incentive effects of food, drugs, and associated cues. In addition, the established role of AMPA receptor
trafficking in enduring synaptic plasticity prompts speculation that drug use during food restriction may more
strongly ingrain behavior relative to similar use under free-feeding conditions.
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Affiliation(s)
- Kenneth D. Carr
- Departments of Psychiatry, Biochemistry and Molecular Pharmacology, New York University School of Medicine, 435 East 30th Street, New York, NY 10016, United States
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41
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Li B, Suutari BS, Sun SD, Luo Z, Wei C, Chenouard N, Mandelberg NJ, Zhang G, Wamsley B, Tian G, Sanchez S, You S, Huang L, Neubert TA, Fishell G, Tsien RW. Neuronal Inactivity Co-opts LTP Machinery to Drive Potassium Channel Splicing and Homeostatic Spike Widening. Cell 2020; 181:1547-1565.e15. [PMID: 32492405 DOI: 10.1016/j.cell.2020.05.013] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 01/28/2020] [Accepted: 05/04/2020] [Indexed: 12/21/2022]
Abstract
Homeostasis of neural firing properties is important in stabilizing neuronal circuitry, but how such plasticity might depend on alternative splicing is not known. Here we report that chronic inactivity homeostatically increases action potential duration by changing alternative splicing of BK channels; this requires nuclear export of the splicing factor Nova-2. Inactivity and Nova-2 relocation were connected by a novel synapto-nuclear signaling pathway that surprisingly invoked mechanisms akin to Hebbian plasticity: Ca2+-permeable AMPA receptor upregulation, L-type Ca2+ channel activation, enhanced spine Ca2+ transients, nuclear translocation of a CaM shuttle, and nuclear CaMKIV activation. These findings not only uncover commonalities between homeostatic and Hebbian plasticity but also connect homeostatic regulation of synaptic transmission and neuronal excitability. The signaling cascade provides a full-loop mechanism for a classic autoregulatory feedback loop proposed ∼25 years ago. Each element of the loop has been implicated previously in neuropsychiatric disease.
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Affiliation(s)
- Boxing Li
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and The Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China; Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA.
| | - Benjamin S Suutari
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA
| | - Simón(e) D. Sun
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA
| | - Zhengyi Luo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, RNA Biomedical Institute, Sun Yat-sen Memorial Hospital, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510120, China
| | - Chuanchuan Wei
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and The Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Nicolas Chenouard
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Nataniel J Mandelberg
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Guoan Zhang
- Department of Biochemistry and Molecular Pharmacology and Skirball Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Brie Wamsley
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA; Stanley Center for Psychiatric Research, The Broad Institute, Cambridge, MA 02142, USA
| | - Guoling Tian
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Sandrine Sanchez
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Sikun You
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and The Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Lianyan Huang
- Neuroscience Program, Guangdong Provincial Key Laboratory of Brain Function and Disease, Zhongshan School of Medicine and The Fifth Affiliated Hospital, Sun Yat-sen University, Guangzhou 510810, China
| | - Thomas A Neubert
- Department of Biochemistry and Molecular Pharmacology and Skirball Institute, NYU Grossman Medical Center, New York, NY 10016, USA
| | - Gordon Fishell
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA; Stanley Center for Psychiatric Research, The Broad Institute, Cambridge, MA 02142, USA
| | - Richard W Tsien
- Department of Neuroscience and Physiology, Neuroscience Institute, NYU Grossman Medical Center, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
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42
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Carr KD. Homeostatic regulation of reward via synaptic insertion of calcium-permeable AMPA receptors in nucleus accumbens. Physiol Behav 2020; 219:112850. [PMID: 32092445 PMCID: PMC7108974 DOI: 10.1016/j.physbeh.2020.112850] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Revised: 01/23/2020] [Accepted: 02/18/2020] [Indexed: 10/25/2022]
Abstract
The incentive effects of food and related cues are determined by stimulus properties and the internal state of the organism. Enhanced hedonic reactivity and incentive motivation in energy deficient subjects have been demonstrated in animal models and humans. Defining the neurobiological underpinnings of these state-based modulatory effects could illuminate fundamental mechanisms of adaptive behavior, as well as provide insight into maladaptive consequences of weight loss dieting and the relationship between disturbed eating behavior and substance abuse. This article summarizes research of our laboratory aimed at identifying neuroadaptations induced by chronic food restriction (FR) that increase the reward magnitude of drugs and associated cues. The main findings are that FR decreases basal dopamine (DA) transmission, upregulates signaling downstream of the D1 DA receptor (D1R), and triggers synaptic incorporation of calcium-permeable AMPA receptors (CP-AMPARs) in the nucleus accumbens (NAc). Selective antagonism of CP-AMPARs decreases excitatory postsynaptic currents in NAc medium spiny neurons of FR rats and blocks the enhanced rewarding effects of d-amphetamine and a D1R, but not a D2R, agonist. These results suggest that FR drives CP-AMPARs into the synaptic membrane of D1R-expressing MSNs, possibly as a homeostatic response to reward loss. FR subjects also display diminished aversion for contexts associated with LiCl treatment and centrally infused cocaine. An encompassing, though speculative, hypothesis is that NAc synaptic incorporation of CP-AMPARs in response to food scarcity and other forms of sustained reward loss adaptively increases incentive effects of reward stimuli and, at the same time, diminishes responsiveness to aversive stimuli that have potential to interfere with goal pursuit.
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Affiliation(s)
- Kenneth D Carr
- Departments of Psychiatry and Biochemistry and Molecular Pharmacology, New York University School of Medicine, 435 East 30th Street, New York, NY 10016, United States.
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43
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Glial ATP and Large Pore Channels Modulate Synaptic Strength in Response to Chronic Inactivity. Mol Neurobiol 2020; 57:2856-2869. [PMID: 32388797 DOI: 10.1007/s12035-020-01919-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 04/14/2020] [Indexed: 01/08/2023]
Abstract
A key feature of neurotransmission is its ability to adapt to changes in neuronal environment, which is essential for many brain functions. Homeostatic synaptic plasticity (HSP) emerges as a compensatory mechanism used by neurons to adjust their excitability in response to changes in synaptic activity. Recently, glial cells emerged as modulators for neurotransmission by releasing gliotransmitters into the synaptic cleft through pathways that include P2X7 receptors (P2X7R), connexons, and pannexons. However, the role of gliotransmission in the activity-dependent adjustment of presynaptic strength is still an open question. Here, we investigated whether glial cells participate in HSP upon chronic inactivity and the role of adenosine triphosphate (ATP), connexin43 hemichannels (Cx43HCs), and pannexin1 (Panx1) channels in this process. We used immunocytochemistry against vesicular glutamate transporter 1 (vGlut1) to estimate changes in synaptic strength in hippocampal dissociated cultures. Pharmacological manipulations indicate that glial-derived ATP and P2X7R are required for HSP. In addition, inhibition of Cx43 and Panx1 channels reveals a pivotal role for these channels in the compensatory adjustment of synaptic strength, emerging as new pathways for ATP release upon inactivity. The involvement of Panx1 channels was confirmed by using Panx1-deficient animals. Lacking Panx1 in neurons is sufficient to prevent the P2X7R-dependent upregulation of presynaptic strength; however, the P2X7R-dependent compensatory adjustment of synapse density requires both neuronal and glial Panx1. Together, our data supports an essential role for glial ATP signaling and Cx43HCs and Panx1 channels in the homeostatic adjustment of synaptic strength in hippocampal cultures upon chronic inactivity.
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Tominaga-Yoshino K, Urakubo T, Ueno Y, Kawaai K, Saito S, Tashiro T, Ogura A. Transient appearance of Ca 2+ -permeable AMPA receptors is crucial for the production of repetitive LTP-induced synaptic enhancement (RISE) in cultured hippocampal slices. Hippocampus 2020; 30:763-769. [PMID: 32320117 DOI: 10.1002/hipo.23206] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 03/17/2020] [Accepted: 03/20/2020] [Indexed: 02/06/2023]
Abstract
We have previously shown that repetitive induction of long-term potentiation (LTP) by glutamate (100 μM, 3 min, three times at 24-hr intervals) provoked long-lasting synaptic enhancement accompanied by synaptogenesis in rat hippocampal slice cultures, a phenomenon termed RISE (repetitive LTP-induced synaptic enhancement). Here, we examined the role of Ca2+ -permeable (CP) AMPA receptors (AMPARs) in the establishment of RISE. We first found a component sensitive to the Joro-spider toxin (JSTX), a blocker of CP-AMPARs, in a field EPSP recorded from CA3-CA1 synapses at 2-3 days after stimulation, but this component was not found for 9-10 days. We also observed that rectification of AMPAR-mediated current appeared only 2-3 days after stimulation, using a whole-cell patch clamp recording from CA1 pyramidal neurons. These findings indicate that CP-AMPAR is transiently expressed in the developing phase of RISE. The blockade of CP-AMPARs by JSTX for 24 hr at this developing phase inhibited RISE establishment, accompanied by the loss of small synapses at the ultrastructural level. These results suggest that transiently induced CP-AMPARs play a critical role in synaptogenesis in the developing phase of long-lasting hippocampal synaptic plasticity, RISE.
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Affiliation(s)
- Keiko Tominaga-Yoshino
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Osaka, Japan
| | - Tomoyoshi Urakubo
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Osaka, Japan
| | - Yukiko Ueno
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Osaka, Japan
| | - Katsuhiro Kawaai
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama-Gakuin University, Kanagawa, Japan
| | - Shinichi Saito
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Osaka, Japan
| | - Tomoko Tashiro
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama-Gakuin University, Kanagawa, Japan
| | - Akihiko Ogura
- Department of Neuroscience, Osaka University Graduate School of Frontier Biosciences, Osaka, Japan
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Sanderson TM, Georgiou J, Collingridge GL. Illuminating Relationships Between the Pre- and Post-synapse. Front Neural Circuits 2020; 14:9. [PMID: 32308573 PMCID: PMC7146027 DOI: 10.3389/fncir.2020.00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Excitatory synapses in the mammalian cortex are highly diverse, both in terms of their structure and function. However, relationships between synaptic features indicate they are highly coordinated entities. Imaging techniques, that enable physiology at the resolution of individual synapses to be investigated, have allowed the presynaptic activity level of the synapse to be related to postsynaptic function. This approach has revealed that neuronal activity induces the pre- and post-synapse to be functionally correlated and that subsets of synapses are more susceptible to certain forms of synaptic plasticity. As presynaptic function is often examined in isolation from postsynaptic properties, the effect it has on the post-synapse is not fully understood. However, since postsynaptic receptors at excitatory synapses respond to release of glutamate, it follows that they may be differentially regulated depending on the frequency of its release. Therefore, examining postsynaptic properties in the context of presynaptic function may be a useful way to approach a broad range of questions on synaptic physiology. In this review, we focus on how optophysiology tools have been utilized to study relationships between the pre- and the post-synapse. Multiple imaging techniques have revealed correlations in synaptic properties from the submicron to the dendritic level. Optical tools together with advanced imaging techniques are ideally suited to illuminate this area further, due to the spatial resolution and control they allow.
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Affiliation(s)
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Graham L Collingridge
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.,Tanz Centre for Research in Neurodegenerative Diseases, Department of Physiology, University of Toronto, Toronto, ON, Canada.,Glutamate Research Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
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Divergent Synaptic Scaling of Miniature EPSCs following Activity Blockade in Dissociated Neuronal Cultures. J Neurosci 2020; 40:4090-4102. [PMID: 32312887 DOI: 10.1523/jneurosci.1393-19.2020] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 03/28/2020] [Accepted: 03/31/2020] [Indexed: 11/21/2022] Open
Abstract
Neurons can respond to decreased network activity with a homeostatic increase in the amplitudes of miniature EPSCs (mEPSCs). The prevailing view is that mEPSC amplitudes are uniformly multiplied by a single factor, termed "synaptic scaling." Deviations from purely multiplicative scaling have been attributed to biological differences, or to a distortion imposed by a detection threshold limit. Here, we demonstrate in neurons dissociated from cortices of male and female mice that the shift in mEPSC amplitudes observed in the experimental data cannot be reproduced by simulation of uniform multiplicative scaling, with or without the distortion caused by applying a detection threshold. Furthermore, we demonstrate explicitly that the scaling factor is not uniform but is close to 1 for small mEPSCs, and increases with increasing mEPSC amplitude across a substantial portion of the data. This pattern was also observed for previously published data from dissociated mouse hippocampal neurons and dissociated rat cortical neurons. The finding of "divergent scaling" shifts the current view of homeostatic plasticity as a process that alters all synapses on a neuron equally to one that must accommodate the differential effect observed for small versus large mEPSCs. Divergent scaling still accomplishes the essential homeostatic task of modifying synaptic strengths in the opposite direction of the activity change, but the consequences are greatest for those synapses which individually are more likely to bring a neuron to threshold.SIGNIFICANCE STATEMENT In homeostatic plasticity, the responses to chronic increases or decreases in network activity act in the opposite direction to restore normal activity levels. Homeostatic plasticity is likely to play a role in diseases associated with long-term changes in brain function, such as epilepsy and neuropsychiatric illnesses. One homeostatic response is the increase in synaptic strength following a chronic block of activity. Research is focused on finding a globally expressed signaling pathway, because it has been proposed that the plasticity is uniformly expressed across all synapses. Here, we show that the plasticity is not uniform. Our work suggests that homeostatic signaling molecules are likely to be differentially expressed across synapses.
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Lin Z, Meng L, Zou J, Zhou W, Huang X, Xue S, Bian T, Yuan T, Niu L, Guo Y, Zheng H. Non-invasive ultrasonic neuromodulation of neuronal excitability for treatment of epilepsy. Theranostics 2020; 10:5514-5526. [PMID: 32373225 PMCID: PMC7196311 DOI: 10.7150/thno.40520] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 01/10/2020] [Indexed: 12/19/2022] Open
Abstract
Non-invasive low-intensity pulsed ultrasound has been employed for direct neuro-modulation. However, its range and effectiveness for different neurological disorders have not been fully elucidated. Methods: We used multiple approaches of electrophysiology, immunohistochemistry, and behavioral tests as potential epilepsy treatments in non-human primate model of epilepsy and human epileptic tissues. Low-intensity pulsed ultrasound with a frequency of 750 kHz and acoustic pressure of 0.35 MPa (the spatial peak pulse average intensity, ISPPA = 2.02 W/cm2) were delivered to the epileptogenic foci in five penicillin-induced epileptic monkey models. An ultrasound neuro-modulation system with a frequency of 28 MHz and acoustic pressure of 0.13 MPa (ISPPA = 465 mW/cm2) compatible with patch-clamp systems was used to stimulate the brain slices prepared from fifteen patients with epilepsy. Results: After 30 min of low-intensity pulsed ultrasound treatment, total seizure count for 16 hours (sham group: 107.7 ± 1.2, ultrasound group: 66.0 ± 7.9, P < 0.01) and seizure frequency per hour (sham group: 15.6 ± 1.2, ultrasound group: 9.6 ± 1.5, P < 0.05) were significantly reduced. The therapeutic efficacy and underlying potential mechanism of low-intensity pulsed ultrasound treatment were studied in biopsy specimens from epileptic patients in vitro. Ultrasound stimulation could inhibit epileptiform activities with an efficiency exceeding 65%, potentially due to adjusting the balance of excitatory-inhibitory (E/I) synaptic inputs by the increased activity of local inhibitory neurons. Conclusion: Herein, we demonstrated for the first time that low-intensity pulsed ultrasound improves electrophysiological activities and behavioral outcomes in a non-human primate model of epilepsy and suppresses epileptiform activities of neurons from human epileptic slices. The study provides evidence for the potential clinical use of non-invasive low-intensity pulsed ultrasound stimulation for epilepsy treatment.
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48
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Dörrbaum AR, Alvarez-Castelao B, Nassim-Assir B, Langer JD, Schuman EM. Proteome dynamics during homeostatic scaling in cultured neurons. eLife 2020; 9:e52939. [PMID: 32238265 PMCID: PMC7117909 DOI: 10.7554/elife.52939] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/22/2020] [Indexed: 12/11/2022] Open
Abstract
Protein turnover, the net result of protein synthesis and degradation, enables cells to remodel their proteomes in response to internal and external cues. Previously, we analyzed protein turnover rates in cultured brain cells under basal neuronal activity and found that protein turnover is influenced by subcellular localization, protein function, complex association, cell type of origin, and by the cellular environment (Dörrbaum et al., 2018). Here, we advanced our experimental approach to quantify changes in protein synthesis and degradation, as well as the resulting changes in protein turnover or abundance in rat primary hippocampal cultures during homeostatic scaling. Our data demonstrate that a large fraction of the neuronal proteome shows changes in protein synthesis and/or degradation during homeostatic up- and down-scaling. More than half of the quantified synaptic proteins were regulated, including pre- as well as postsynaptic proteins with diverse molecular functions.
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Affiliation(s)
- Aline Ricarda Dörrbaum
- Max Planck Institute for Brain Research, Frankfurt, Germany
- Goethe University Frankfurt, Faculty of Biological Sciences, Frankfurt, Germany
| | | | | | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt, Germany
- Max Planck Institute of Biophysics, Frankfurt, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany
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Purkey AM, Dell’Acqua ML. Phosphorylation-Dependent Regulation of Ca 2+-Permeable AMPA Receptors During Hippocampal Synaptic Plasticity. Front Synaptic Neurosci 2020; 12:8. [PMID: 32292336 PMCID: PMC7119613 DOI: 10.3389/fnsyn.2020.00008] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 02/18/2020] [Indexed: 01/28/2023] Open
Abstract
Experience-dependent learning and memory require multiple forms of plasticity at hippocampal and cortical synapses that are regulated by N-methyl-D-aspartate receptors (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-type ionotropic glutamate receptors (NMDAR, AMPAR). These plasticity mechanisms include long-term potentiation (LTP) and depression (LTD), which are Hebbian input-specific mechanisms that rapidly increase or decrease AMPAR synaptic strength at specific inputs, and homeostatic plasticity that globally scales-up or -down AMPAR synaptic strength across many or even all inputs. Frequently, these changes in synaptic strength are also accompanied by a change in the subunit composition of AMPARs at the synapse due to the trafficking to and from the synapse of receptors lacking GluA2 subunits. These GluA2-lacking receptors are most often GluA1 homomeric receptors that exhibit higher single-channel conductance and are Ca2+-permeable (CP-AMPAR). This review article will focus on the role of protein phosphorylation in regulation of GluA1 CP-AMPAR recruitment and removal from hippocampal synapses during synaptic plasticity with an emphasis on the crucial role of local signaling by the cAMP-dependent protein kinase (PKA) and the Ca2+calmodulin-dependent protein phosphatase 2B/calcineurin (CaN) that is coordinated by the postsynaptic scaffold protein A-kinase anchoring protein 79/150 (AKAP79/150).
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Affiliation(s)
| | - Mark L. Dell’Acqua
- Department of Pharmacology, University of Colorado School of Medicine, Anschutz Medical Campus, Aurora, CO, United States
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50
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Field RE, D'amour JA, Tremblay R, Miehl C, Rudy B, Gjorgjieva J, Froemke RC. Heterosynaptic Plasticity Determines the Set Point for Cortical Excitatory-Inhibitory Balance. Neuron 2020; 106:842-854.e4. [PMID: 32213321 DOI: 10.1016/j.neuron.2020.03.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 12/27/2019] [Accepted: 03/03/2020] [Indexed: 01/24/2023]
Abstract
Excitation in neural circuits must be carefully controlled by inhibition to regulate information processing and network excitability. During development, cortical inhibitory and excitatory inputs are initially mismatched but become co-tuned or balanced with experience. However, little is known about how excitatory-inhibitory balance is defined at most synapses or about the mechanisms for establishing or maintaining this balance at specific set points. Here we show how coordinated long-term plasticity calibrates populations of excitatory-inhibitory inputs onto mouse auditory cortical pyramidal neurons. Pairing pre- and postsynaptic activity induced plasticity at paired inputs and different forms of heterosynaptic plasticity at the strongest unpaired synapses, which required minutes of activity and dendritic Ca2+ signaling to be computed. Theoretical analyses demonstrated how the relative rate of heterosynaptic plasticity could normalize and stabilize synaptic strengths to achieve any possible excitatory-inhibitory correlation. Thus, excitatory-inhibitory balance is dynamic and cell specific, determined by distinct plasticity rules across multiple excitatory and inhibitory synapses.
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Affiliation(s)
- Rachel E Field
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA; Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | - James A D'amour
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA; Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA
| | - Robin Tremblay
- Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA; Department of Anesthesiology, New York University School of Medicine, New York, NY 10016, USA
| | - Christoph Miehl
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany; School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Bernardo Rudy
- Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA; Department of Anesthesiology, New York University School of Medicine, New York, NY 10016, USA
| | - Julijana Gjorgjieva
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany; School of Life Sciences, Technical University of Munich, 85354 Freising, Germany
| | - Robert C Froemke
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA; Neuroscience Institute, New York University School of Medicine, New York, NY 10016, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY 10016, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY 10016, USA; Center for Neural Science, New York University, New York, NY 10003, USA.
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