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Wen W, Turrigiano GG. Keeping Your Brain in Balance: Homeostatic Regulation of Network Function. Annu Rev Neurosci 2024; 47:41-61. [PMID: 38382543 DOI: 10.1146/annurev-neuro-092523-110001] [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: 02/23/2024]
Abstract
To perform computations with the efficiency necessary for animal survival, neocortical microcircuits must be capable of reconfiguring in response to experience, while carefully regulating excitatory and inhibitory connectivity to maintain stable function. This dynamic fine-tuning is accomplished through a rich array of cellular homeostatic plasticity mechanisms that stabilize important cellular and network features such as firing rates, information flow, and sensory tuning properties. Further, these functional network properties can be stabilized by different forms of homeostatic plasticity, including mechanisms that target excitatory or inhibitory synapses, or that regulate intrinsic neuronal excitability. Here we discuss which aspects of neocortical circuit function are under homeostatic control, how this homeostasis is realized on the cellular and molecular levels, and the pathological consequences when circuit homeostasis is impaired. A remaining challenge is to elucidate how these diverse homeostatic mechanisms cooperate within complex circuits to enable them to be both flexible and stable.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
| | - Gina G Turrigiano
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
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2
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Bagatelas ED, Kavalali ET. Chronic modulation of cAMP signaling elicits synaptic scaling irrespective of activity. iScience 2024; 27:110176. [PMID: 38989459 PMCID: PMC11233962 DOI: 10.1016/j.isci.2024.110176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 04/11/2024] [Accepted: 05/31/2024] [Indexed: 07/12/2024] Open
Abstract
Homeostatic plasticity mechanisms act in a negative feedback manner to stabilize neuronal firing around a set point. Classically, homeostatic synaptic plasticity is elicited via rather drastic manipulation of activity in a neuronal population. Here, we employed a chemogenetic approach to regulate activity via eliciting G protein-coupled receptor (GPCR) signaling in hippocampal neurons to trigger homeostatic synaptic plasticity. We demonstrate that chronic activation of hM4D(Gi) signaling induces mild and transient activity suppression, yet still triggers synaptic upscaling akin to tetrodotoxin (TTX)-induced complete activity suppression. Therefore, this homeostatic regulation was irrespective of Gi-signaling regulation of activity, but it was mimicked or occluded by direct manipulation of cyclic AMP (cAMP) signaling in a manner that intersected with the retinoic acid receptor alpha (RARα) signaling pathway. Our data suggest chemogenetic tools can uniquely be used to probe cell-autonomous mechanisms of synaptic scaling and operate via direct modulation of second messenger signaling bypassing activity regulation.
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Affiliation(s)
- Elena D. Bagatelas
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37209, USA
| | - Ege T. Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37209, USA
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3
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Koesters AG, Rich MM, Engisch KL. Homeostatic Synaptic Plasticity of Miniature Excitatory Postsynaptic Currents in Mouse Cortical Cultures Requires Neuronal Rab3A. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.06.14.544980. [PMID: 39071374 PMCID: PMC11275788 DOI: 10.1101/2023.06.14.544980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Following prolonged activity blockade, amplitudes of miniature excitatory postsynaptic currents (mEPSCs) increase, a form of plasticity termed "homeostatic synaptic plasticity." We previously showed that a presynaptic protein, the small GTPase Rab3A, is required for full expression of the increase in miniature endplate current amplitudes following prolonged blockade of action potential activity at the mouse neuromuscular junction in vivo (Wang et al., 2011), but it is unknown whether this form of Rab3A-dependent homeostatic plasticity shares any characteristics with central synapses. We show here that homeostatic synaptic plasticity of mEPSCs is impaired in mouse cortical neuron cultures prepared from Rab3A-/- and mutant mice expressing a single point mutation of Rab3A, Rab3A Earlybird mice. To determine if Rab3A is involved in the well-established homeostatic increase in postsynaptic AMPA-type receptors (AMPARs), we performed a series of experiments in which electrophysiological recordings of mEPSCs and confocal imaging of synaptic AMPAR immunofluorescence were assessed within the same cultures. We found that Rab3A was required for the increase in synaptic AMPARs following prolonged activity blockade, but the increase in mEPSC amplitudes was not always accompanied by an increase in postsynaptic AMPAR levels, suggesting other factors may contribute. Finally, we demonstrate that Rab3A is acting in neurons because only selective loss of Rab3A in neurons, not glia, disrupted the homeostatic increase in mEPSC amplitudes. This is the first demonstration that neuronal Rab3A is required for homeostatic synaptic plasticity and that it does so partially through regulation of the surface expression of AMPA receptors.
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Affiliation(s)
- Andrew G. Koesters
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
| | - Mark M. Rich
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45345
| | - Kathrin L. Engisch
- Department of Neuroscience, Cell Biology and Physiology, Boonshoft School of Medicine and the College of Science and Mathematics, Wright State University, Dayton, OH 45435
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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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5
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Gonzalez-Islas C, Sabra Z, Fong MF, Yilmam P, Au Yong N, Engisch K, Wenner P. GABAergic synaptic scaling is triggered by changes in spiking activity rather than AMPA receptor activation. eLife 2024; 12:RP87753. [PMID: 38941139 PMCID: PMC11213567 DOI: 10.7554/elife.87753] [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] [Indexed: 06/29/2024] Open
Abstract
Homeostatic plasticity represents a set of mechanisms that are thought to recover some aspect of neural function. One such mechanism called AMPAergic scaling was thought to be a likely candidate to homeostatically control spiking activity. However, recent findings have forced us to reconsider this idea as several studies suggest AMPAergic scaling is not directly triggered by changes in spiking. Moreover, studies examining homeostatic perturbations in vivo have suggested that GABAergic synapses may be more critical in terms of spiking homeostasis. Here, we show results that GABAergic scaling can act to homeostatically control spiking levels. We found that perturbations which increased or decreased spiking in cortical cultures triggered multiplicative GABAergic upscaling and downscaling, respectively. In contrast, we found that changes in AMPA receptor (AMPAR) or GABAR transmission only influence GABAergic scaling through their indirect effect on spiking. We propose that GABAergic scaling represents a stronger candidate for spike rate homeostat than AMPAergic scaling.
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Affiliation(s)
- Carlos Gonzalez-Islas
- Department of Cell Biology, Emory UniversityAtlantaUnited States
- Doctorado en Ciencias Biológicas Universidad Autónoma de TlaxcalaTlaxMexico
| | - Zahraa Sabra
- Department of Neurosurgery, Emory UniversityAtlantaUnited States
| | - Ming-fai Fong
- Department of Cell Biology, Emory UniversityAtlantaUnited States
- Department of Biomedical Engineering, Georgia Tech and Emory UniversityAtlantaUnited States
| | - Pernille Yilmam
- Department of Cell Biology, Emory UniversityAtlantaUnited States
| | - Nicholas Au Yong
- Department of Neurosurgery, Emory UniversityAtlantaUnited States
| | - Kathrin Engisch
- Department of Neuroscience, Cell Biology and Physiology, Wright State UniversityDaytonUnited States
| | - Peter Wenner
- Department of Cell Biology, Emory UniversityAtlantaUnited States
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Wen W, Turrigiano GG. Modular Arrangement of Synaptic and Intrinsic Homeostatic Plasticity within Visual Cortical Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596982. [PMID: 38853882 PMCID: PMC11160741 DOI: 10.1101/2024.06.01.596982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Neocortical circuits use synaptic and intrinsic forms of homeostatic plasticity to stabilize key features of network activity, but whether these different homeostatic mechanisms act redundantly, or can be independently recruited to stabilize different network features, is unknown. Here we used pharmacological and genetic perturbations both in vitro and in vivo to determine whether synaptic scaling and intrinsic homeostatic plasticity (IHP) are arranged and recruited in a hierarchical or modular manner within L2/3 pyramidal neurons in rodent V1. Surprisingly, although the expression of synaptic scaling and IHP was dependent on overlapping trafficking pathways, they could be independently recruited by manipulating spiking activity or NMDAR signaling, respectively. Further, we found that changes in visual experience that affect NMDAR activation but not mean firing selectively trigger IHP, without recruiting synaptic scaling. These findings support a modular model in which synaptic and intrinsic homeostatic plasticity respond to and stabilize distinct aspects of network activity.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
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Nascimento F, Özyurt MG, Halablab K, Bhumbra GS, Caron G, Bączyk M, Zytnicki D, Manuel M, Roselli F, Brownstone R, Beato M. Spinal microcircuits go through multiphasic homeostatic compensations in a mouse model of motoneuron degeneration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.10.588918. [PMID: 38645210 PMCID: PMC11030447 DOI: 10.1101/2024.04.10.588918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
In neurological conditions affecting the brain, early-stage neural circuit adaption is key for long-term preservation of normal behaviour. We tested if motoneurons and respective microcircuits also adapt in the initial stages of disease progression in a mouse model of progressive motoneuron degeneration. Using a combination of in vitro and in vivo electrophysiology and super-resolution microscopy, we found that, preceding muscle denervation and motoneuron death, recurrent inhibition mediated by Renshaw cells is reduced in half due to impaired quantal size associated with decreased glycine receptor density. Additionally, higher probability of release from proprioceptive Ia terminals leads to increased monosynaptic excitation to motoneurons. Surprisingly, the initial impairment in recurrent inhibition is not a widespread feature of inhibitory spinal circuits, such as group I inhibitory afferents, and is compensated at later stages of disease progression. We reveal that in disease conditions, spinal microcircuits undergo specific multiphasic homeostatic compensations to preserve force output.
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Affiliation(s)
- Filipe Nascimento
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - M. Görkem Özyurt
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Kareen Halablab
- Department of Neurology, Ulm University, Ulm, Germany
- German Centre for Neurodegenerative Diseases-Ulm (DZNE-Ulm), Ulm, Germany
| | - Gardave Singh Bhumbra
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
| | - Guillaume Caron
- Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Marcin Bączyk
- Department of Neurobiology, Poznań University of Physical Education, Poznań, Poland
| | - Daniel Zytnicki
- Saints-Pères Paris Institute for the Neurosciences (SPPIN), Université Paris Cité, Centre National de la Recherche Scientifique (CNRS), Paris, France
| | - Marin Manuel
- Department of Biomedical and Pharmaceutical Sciences, College of Pharmacy, University of Rhode Island, USA
- George and Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany
- German Centre for Neurodegenerative Diseases-Ulm (DZNE-Ulm), Ulm, Germany
| | - Rob Brownstone
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Marco Beato
- Department of Neuroscience Physiology and Pharmacology (NPP), Gower Street, University College London, WC1E 6BT, UK
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Chen Y, Liu S, Jacobi AA, Jeng G, Ulrich JD, Stein IS, Patriarchi T, Hell JW. Rapid sequential clustering of NMDARs, CaMKII, and AMPARs upon activation of NMDARs at developing synapses. Front Synaptic Neurosci 2024; 16:1291262. [PMID: 38660466 PMCID: PMC11039796 DOI: 10.3389/fnsyn.2024.1291262] [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: 09/08/2023] [Accepted: 03/22/2024] [Indexed: 04/26/2024] Open
Abstract
Rapid, synapse-specific neurotransmission requires the precise alignment of presynaptic neurotransmitter release and postsynaptic receptors. How postsynaptic glutamate receptor accumulation is induced during maturation is not well understood. We find that in cultures of dissociated hippocampal neurons at 11 days in vitro (DIV) numerous synaptic contacts already exhibit pronounced accumulations of the pre- and postsynaptic markers synaptotagmin, synaptophysin, synapsin, bassoon, VGluT1, PSD-95, and Shank. The presence of an initial set of AMPARs and NMDARs is indicated by miniature excitatory postsynaptic currents (mEPSCs). However, AMPAR and NMDAR immunostainings reveal rather smooth distributions throughout dendrites and synaptic enrichment is not obvious. We found that brief periods of Ca2+ influx through NMDARs induced a surprisingly rapid accumulation of NMDARs within 1 min, followed by accumulation of CaMKII and then AMPARs within 2-5 min. Postsynaptic clustering of NMDARs and AMPARs was paralleled by an increase in their mEPSC amplitudes. A peptide that blocked the interaction of NMDAR subunits with PSD-95 prevented the NMDAR clustering. NMDAR clustering persisted for 3 days indicating that brief periods of elevated glutamate fosters permanent accumulation of NMDARs at postsynaptic sites in maturing synapses. These data support the model that strong glutamatergic stimulation of immature glutamatergic synapses results in a fast and substantial increase in postsynaptic NMDAR content that required NMDAR binding to PSD-95 or its homologues and is followed by recruitment of CaMKII and subsequently AMPARs.
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Affiliation(s)
- Yucui Chen
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Shangming Liu
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Ariel A. Jacobi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Grace Jeng
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Jason D. Ulrich
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
| | - Ivar S. Stein
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Tommaso Patriarchi
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
| | - Johannes W. Hell
- Department of Pharmacology, University of Iowa, Iowa City, IA, United States
- Department of Pharmacology, University of California, Davis, Davis, CA, United States
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9
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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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10
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Abstract
Major depressive disorder (MDD) is a leading cause of suicide in the world. Monoamine-based antidepressant drugs are a primary line of treatment for this mental disorder, although the delayed response and incomplete efficacy in some patients highlight the need for improved therapeutic approaches. Over the past two decades, ketamine has shown rapid onset with sustained (up to several days) antidepressant effects in patients whose MDD has not responded to conventional antidepressant drugs. Recent preclinical studies have started to elucidate the underlying mechanisms of ketamine's antidepressant properties. Herein, we describe and compare recent clinical and preclinical findings to provide a broad perspective of the relevant mechanisms for the antidepressant action of ketamine.
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Affiliation(s)
- Ji-Woon Kim
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, Tennessee, USA;
- College of Pharmacy, Kyung Hee University, Seoul, Republic of Korea
- Department of Regulatory Science, Graduate School, Kyung Hee University, Seoul, Republic of Korea
- Institute of Regulatory Innovation through Science, Kyung Hee University, Seoul, Republic of Korea
| | - Kanzo Suzuki
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, Tennessee, USA;
- Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Tokyo, Japan
| | - Ege T Kavalali
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, Tennessee, USA;
| | - Lisa M Monteggia
- Department of Pharmacology, School of Medicine, Vanderbilt University, Nashville, Tennessee, USA;
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Wan C, Song X, Zhang Z, Hu W, Chen Y, Sun W, Liu Z, Wang S, Meng W. Voluntary exercise during puberty promotes spatial memory and hippocampal DG/CA3 synaptic transmission in mice. Cereb Cortex 2024; 34:bhad497. [PMID: 38124544 DOI: 10.1093/cercor/bhad497] [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: 10/08/2023] [Revised: 12/01/2023] [Accepted: 12/03/2023] [Indexed: 12/23/2023] Open
Abstract
Physical exercise has been shown to have an impact on memory and hippocampal function across different age groups. Nevertheless, the influence and mechanisms underlying how voluntary exercise during puberty affects memory are still inadequately comprehended. This research aims to examine the impacts of self-initiated physical activity throughout adolescence on spatial memory. Developing mice were exposed to a 4-wk voluntary wheel running exercise protocol, commencing at the age of 30 d. After engaging in voluntary wheel running exercise during development, there was an enhancement in spatial memory. Moreover, hippocampal dentate gyrus and CA3 neurons rather than CA1 neurons exhibited an increase in the miniature excitatory postsynaptic currents and miniature inhibitory postsynaptic currents. In addition, there was an increase in the expression of NR2A/NR2B subunits of N-methyl-D-aspartate receptors and α1GABAA subunit of gamma-aminobutyric acid type A receptors, as well as dendritic spine density, specifically within dentate gyrus and CA3 regions rather than CA1 region. The findings suggest that voluntary exercise during development can enhance spatial memory in mice by increasing synapse numbers and improving synaptic transmission in hippocampal dentate gyrus and CA3 regions, but not in CA1 region. This study sheds light on the neural mechanisms underlying how early-life exercise improves cognitive function.
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Affiliation(s)
- Changjian Wan
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Xueqing Song
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Zhuyu Zhang
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wenxiang Hu
- School of Life Sciences, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 33001, China
| | - Yanhua Chen
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wei Sun
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Zhibin Liu
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Songhua Wang
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
| | - Wei Meng
- Jiangxi Key Laboratory of Organic Chemistry, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
- School of Physical Education and Health, Jiangxi Science and Technology Normal University, 605 Fenglin Rd, Nanchang, Jiangxi Province 330013, China
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12
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Barabási DL, Schuhknecht GFP, Engert F. Functional neuronal circuits emerge in the absence of developmental activity. Nat Commun 2024; 15:364. [PMID: 38191595 PMCID: PMC10774424 DOI: 10.1038/s41467-023-44681-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 12/29/2023] [Indexed: 01/10/2024] Open
Abstract
The complex neuronal circuitry of the brain develops from limited information contained in the genome. After the genetic code instructs the birth of neurons, the emergence of brain regions, and the formation of axon tracts, it is believed that temporally structured spiking activity shapes circuits for behavior. Here, we challenge the learning-dominated assumption that spiking activity is required for circuit formation by quantifying its contribution to the development of visually-guided swimming in the larval zebrafish. We found that visual experience had no effect on the emergence of the optomotor response (OMR) in dark-reared zebrafish. We then raised animals while pharmacologically silencing action potentials with the sodium channel blocker tricaine. After washout of the anesthetic, fish could swim and performed with 75-90% accuracy in the OMR paradigm. Brain-wide imaging confirmed that neuronal circuits came 'online' fully tuned, without requiring activity-dependent plasticity. Thus, complex sensory-guided behaviors can emerge through activity-independent developmental mechanisms.
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Affiliation(s)
- Dániel L Barabási
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA.
- Biophysics Program, Harvard University, Cambridge, MA, USA.
| | | | - Florian Engert
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA, USA
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Kruse P, Brandes G, Hemeling H, Huang Z, Wrede C, Hegermann J, Vlachos A, Lenz M. Synaptopodin Regulates Denervation-Induced Plasticity at Hippocampal Mossy Fiber Synapses. Cells 2024; 13:114. [PMID: 38247806 PMCID: PMC10814840 DOI: 10.3390/cells13020114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 12/17/2023] [Accepted: 12/27/2023] [Indexed: 01/23/2024] Open
Abstract
Neurological diseases can lead to the denervation of brain regions caused by demyelination, traumatic injury or cell death. The molecular and structural mechanisms underlying lesion-induced reorganization of denervated brain regions, however, are a matter of ongoing investigation. In order to address this issue, we performed an entorhinal cortex lesion (ECL) in mouse organotypic entorhino-hippocampal tissue cultures of both sexes and studied denervation-induced plasticity of mossy fiber synapses, which connect dentate granule cells (dGCs) with CA3 pyramidal cells (CA3-PCs) and play important roles in learning and memory formation. Partial denervation caused a strengthening of excitatory neurotransmission in dGCs, CA3-PCs and their direct synaptic connections, as revealed by paired recordings (dGC-to-CA3-PC). These functional changes were accompanied by ultrastructural reorganization of mossy fiber synapses, which regularly contain the plasticity-regulating protein synaptopodin and the spine apparatus organelle. We demonstrate that the spine apparatus organelle and synaptopodin are related to ribosomes in close proximity to synaptic sites and reveal a synaptopodin-related transcriptome. Notably, synaptopodin-deficient tissue preparations that lack the spine apparatus organelle failed to express lesion-induced synaptic adjustments. Hence, synaptopodin and the spine apparatus organelle play a crucial role in regulating lesion-induced synaptic plasticity at hippocampal mossy fiber synapses.
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Affiliation(s)
- Pia Kruse
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Gudrun Brandes
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
| | - Hanna Hemeling
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
| | - Zhong Huang
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
| | - Christoph Wrede
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, 30625 Hannover, Germany
| | - Jan Hegermann
- Institute of Functional and Applied Anatomy, Hannover Medical School, 30625 Hannover, Germany
- Research Core Unit Electron Microscopy, Hannover Medical School, 30625 Hannover, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, 79104 Freiburg, Germany
| | - Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, 79104 Freiburg, Germany
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, 30625 Hannover, Germany
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14
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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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15
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Fetterly TL, Catalfio AM, Ferrario CR. Effects of junk-food on food-motivated behavior and nucleus accumbens glutamate plasticity; insights into the mechanism of calcium-permeable AMPA receptor recruitment. Neuropharmacology 2024; 242:109772. [PMID: 37898332 PMCID: PMC10883075 DOI: 10.1016/j.neuropharm.2023.109772] [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: 08/14/2023] [Revised: 10/03/2023] [Accepted: 10/17/2023] [Indexed: 10/30/2023]
Abstract
In rats, eating obesogenic diets increases calcium-permeable AMPA receptor (CP-AMPAR) transmission in the nucleus accumbens (NAc) core, and enhances food-motivated behavior. Interestingly, these diet-induced alterations in NAc transmission are pronounced and sustained in obesity-prone (OP) male rats and absent in obesity-resistant (OR) populations. However, effects of diet manipulation on food motivation, and the mechanisms underlying this NAc plasticity in OPs is unknown. Using male selectively-bred OP and OR rats, we assessed food-motivated behavior following ad lib access to chow (CH), junk-food (JF), or 10d of JF followed by a return to chow diet (JF-Dep). Motivation for food was greater in OP than OR rats, as expected. However, JF-Dep only produced enhancements in food-seeking in OP groups, while continuous JF access reduced food-seeking in both OPs and ORs. Additionally, optogenetic, chemogenetic, and pharmacological approaches were used to examine NAc CP-AMPAR recruitment following diet manipulation and ex vivo treatment of brain slices. Reducing excitatory transmission in the NAc was sufficient to recruit CP-AMPARs to synapses in OPs, but not ORs. In OPs, JF-induced increases in CP-AMPARs occurred in mPFC-, but not BLA-to-NAc inputs. Together results show that diet differentially affects behavioral and neural plasticity in obesity susceptible populations. We also identify conditions for acute recruitment of NAc CP-AMPARs; these results suggest that synaptic scaling mechanisms contribute to NAc CP-AMPAR recruitment. Overall, this work helps elucidate how diet interacts with obesity susceptibility to influence food-motivated behavior and extends our fundamental understanding of NAc CP-AMPAR recruitment.
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Affiliation(s)
- Tracy L Fetterly
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Amanda M Catalfio
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carrie R Ferrario
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA; Psychology Department (Biopsychology) University of Michigan, Ann Arbor, MI, 48109, USA.
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16
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Yuan X, Puvogel S, van Rhijn JR, Ciptasari U, Esteve-Codina A, Meijer M, Rouschop S, van Hugte EJH, Oudakker A, Schoenmaker C, Frega M, Schubert D, Franke B, Nadif Kasri N. A human in vitro neuronal model for studying homeostatic plasticity at the network level. Stem Cell Reports 2023; 18:2222-2239. [PMID: 37863044 PMCID: PMC10679660 DOI: 10.1016/j.stemcr.2023.09.011] [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: 04/19/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 10/22/2023] Open
Abstract
Mechanisms that underlie homeostatic plasticity have been extensively investigated at single-cell levels in animal models, but are less well understood at the network level. Here, we used microelectrode arrays to characterize neuronal networks following induction of homeostatic plasticity in human induced pluripotent stem cell (hiPSC)-derived glutamatergic neurons co-cultured with rat astrocytes. Chronic suppression of neuronal activity through tetrodotoxin (TTX) elicited a time-dependent network re-arrangement. Increased expression of AMPA receptors and the elongation of axon initial segments were associated with increased network excitability following TTX treatment. Transcriptomic profiling of TTX-treated neurons revealed up-regulated genes related to extracellular matrix organization, while down-regulated genes related to cell communication; also astrocytic gene expression was found altered. Overall, our study shows that hiPSC-derived neuronal networks provide a reliable in vitro platform to measure and characterize homeostatic plasticity at network and single-cell levels; this platform can be extended to investigate altered homeostatic plasticity in brain disorders.
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Affiliation(s)
- Xiuming Yuan
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Sofía Puvogel
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Jon-Ruben van Rhijn
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Ummi Ciptasari
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Anna Esteve-Codina
- CNAG-CRG, Centre for Genomic Regulation, Barcelona Institute of Science and Technology, 08028 Barcelona, Spain; Universitat Pompeu Fabra (UPF), 08002 Barcelona, Spain
| | - Mandy Meijer
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Simon Rouschop
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Eline J H van Hugte
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Astrid Oudakker
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Chantal Schoenmaker
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Monica Frega
- Department of Clinical Neurophysiology, University of Twente, 7522 NB Enschede, the Netherlands
| | - Dirk Schubert
- Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Barbara Franke
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands
| | - Nael Nadif Kasri
- Department of Human Genetics, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands; Department of Cognitive Neuroscience, Radboud University Medical Center, Donders Institute for Brain, Cognition and Behaviour, 6500 HB Nijmegen, the Netherlands.
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Ceanga M, Rahmati V, Haselmann H, Schmidl L, Hunter D, Brauer AK, Liebscher S, Kreye J, Prüss H, Groc L, Hallermann S, Dalmau J, Ori A, Heckmann M, Geis C. Human NMDAR autoantibodies disrupt excitatory-inhibitory balance, leading to hippocampal network hypersynchrony. Cell Rep 2023; 42:113166. [PMID: 37768823 DOI: 10.1016/j.celrep.2023.113166] [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: 05/31/2022] [Revised: 06/30/2023] [Accepted: 09/07/2023] [Indexed: 09/30/2023] Open
Abstract
Anti-NMDA receptor autoantibodies (NMDAR-Abs) in patients with NMDAR encephalitis cause severe disease symptoms resembling psychosis and cause cognitive dysfunction. After passive transfer of patients' cerebrospinal fluid or human monoclonal anti-GluN1-autoantibodies in mice, we find a disrupted excitatory-inhibitory balance resulting from CA1 neuronal hypoexcitability, reduced AMPA receptor (AMPAR) signaling, and faster synaptic inhibition in acute hippocampal slices. Functional alterations are also reflected in widespread remodeling of the hippocampal proteome, including changes in glutamatergic and GABAergic neurotransmission. NMDAR-Abs amplify network γ oscillations and disrupt θ-γ coupling. A data-informed network model reveals that lower AMPAR strength and faster GABAA receptor current kinetics chiefly account for these abnormal oscillations. As predicted in silico and evidenced ex vivo, positive allosteric modulation of AMPARs alleviates aberrant γ activity, reinforcing the causative effects of the excitatory-inhibitory imbalance. Collectively, NMDAR-Ab-induced aberrant synaptic, cellular, and network dynamics provide conceptual insights into NMDAR-Ab-mediated pathomechanisms and reveal promising therapeutic targets that merit future in vivo validation.
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Affiliation(s)
- Mihai Ceanga
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - Vahid Rahmati
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - Holger Haselmann
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - Lars Schmidl
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, 07747 Jena, Germany
| | - Daniel Hunter
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Anna-Katherina Brauer
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Martinsried, Germany; Biomedical Center, Ludwig Maximilians University Munich, Martinsried, Germany
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig Maximilians University Munich, Martinsried, Germany; Biomedical Center, Ludwig Maximilians University Munich, Martinsried, Germany; Munich Cluster for Systems Neurology (SyNergy), Munich, Germany
| | - Jakob Kreye
- Department of Neurology and Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany; Department of Pediatric Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany
| | - Harald Prüss
- Department of Neurology and Experimental Neurology, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 10117 Berlin, Germany; German Center for Neurodegenerative Diseases (DZNE) Berlin, Berlin, Germany
| | - Laurent Groc
- Université de Bordeaux, CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, 33000 Bordeaux, France
| | - Stefan Hallermann
- Carl Ludwig Institute for Physiology, Faculty of Medicine, Leipzig University, 04103 Leipzig, Germany
| | - Josep Dalmau
- Catalan Institution for Research and Advanced Studies (ICREA) and IDIBAPS-Hospital Clinic, University of Barcelona, 08036 Barcelona, Spain
| | - Alessandro Ori
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), 07745 Jena, Germany
| | - Manfred Heckmann
- Department of Neurophysiology, Institute of Physiology, University of Würzburg, 97070 Würzburg, Germany
| | - Christian Geis
- Section of Translational Neuroimmunology, Department of Neurology, Jena University Hospital, 07747 Jena, Germany.
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18
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Canovi A, Orlacchio R, Poulletier de Gannes F, Lévêque P, Arnaud-Cormos D, Lagroye I, Garenne A, Percherancier Y, Lewis N. In vitro exposure of neuronal networks to the 5G-3.5 GHz signal. Front Public Health 2023; 11:1231360. [PMID: 37608978 PMCID: PMC10441122 DOI: 10.3389/fpubh.2023.1231360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 07/18/2023] [Indexed: 08/24/2023] Open
Abstract
Introduction The current deployment of the fifth generation (5G) of wireless communications raises new questions about the potential health effects of exposure to radiofrequency (RF) fields. So far, most of the established biological effects of RF have been known to be caused by heating. We previously reported inhibition of the spontaneous electrical activity of neuronal networks in vitro when exposed to 1.8 GHz signals at specific absorption rates (SAR) well above the guidelines. The present study aimed to assess the effects of RF fields at 3.5 GHz, one of the frequencies related to 5G, on neuronal activity in-vitro. Potential differences in the effects elicited by continuous-wave (CW) and 5G-modulated signals were also investigated. Methods Spontaneous activity of neuronal cultures from embryonic cortices was recorded using 60-electrode multi-electrode arrays (MEAs) between 17 and 27 days in vitro. The neuronal cultures were subjected to 15 min RF exposures at SAR of 1, 3, and 28 W/kg. Results At SAR close to the guidelines (1 and 3 W/kg), we found no conclusive evidence that 3.5 GHz RF exposure impacts the activity of neurons in vitro. On the contrary, CW and 5G-modulated signals elicited a clear decrease in bursting and total firing rates during RF exposure at high SAR levels (28 W/kg). Our experimental findings extend our previous results, showing that RF, at 1.8 to 3.5 GHz, inhibits the electrical activity of neurons in vitro at levels above environmental standards.
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Affiliation(s)
- Anne Canovi
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | - Rosa Orlacchio
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
- Paris Sciences et Lettres Research University, École Pratique des Hautes Études (EPHE), Paris, France
| | | | | | - Delia Arnaud-Cormos
- Univ. Limoges, CNRS, XLIM, UMR 7252, Limoges, France
- Institut Universitaire de France (IUF), Paris, France
| | - Isabelle Lagroye
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
- Paris Sciences et Lettres Research University, École Pratique des Hautes Études (EPHE), Paris, France
| | - André Garenne
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
| | | | - Noëlle Lewis
- Univ. Bordeaux, CNRS, Bordeaux INP, IMS, UMR 5218, Talence, France
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Schröder JK, Abdel-Hafiz L, Ali AAH, Cousin TC, Hallenberger J, Rodrigues Almeida F, Anstötz M, Lenz M, Vlachos A, von Gall C, Tundo-Lavalle F. Effects of the Light/Dark Phase and Constant Light on Spatial Working Memory and Spine Plasticity in the Mouse Hippocampus. Cells 2023; 12:1758. [PMID: 37443792 PMCID: PMC10340644 DOI: 10.3390/cells12131758] [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: 05/25/2023] [Revised: 06/22/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023] Open
Abstract
Circadian rhythms in behavior and physiology such as rest/activity and hormones are driven by an internal clock and persist in the absence of rhythmic environmental cues. However, the period and phase of the internal clock are entrained by the environmental light/dark cycle. Consequently, aberrant lighting conditions, which are increasing in modern society, have a strong impact on rhythmic body and brain functions. Mice were exposed to three different lighting conditions, 12 h light/12 h dark cycle (LD), constant darkness (DD), and constant light (LL), to study the effects of the light/dark cycle and aberrant lighting on the hippocampus, a critical structure for temporal and spatial memory formation and navigation. Locomotor activity and plasma corticosterone levels were analyzed as readouts for circadian rhythms. Spatial working memory via Y-maze, spine morphology of Golgi-Cox-stained hippocampi, and plasticity of excitatory synapses, measured by number and size of synaptopodin and GluR1-immunreactive clusters, were analyzed. Our results indicate that the light/dark cycle drives diurnal differences in synaptic plasticity in hippocampus. Moreover, spatial working memory, spine density, and size and number of synaptopodin and GluR1 clusters were reduced in LL, while corticosterone levels were increased. This indicates that acute constant light affects hippocampal function and synaptic plasticity.
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Affiliation(s)
- Jane K. Schröder
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
- Department of Pediatric Hematology and Oncology, Medical Faculty, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Laila Abdel-Hafiz
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Amira A. H. Ali
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
- Department of Human Anatomy and Embryology, Faculty of Medicine, Mansoura University, El-Gomhoria St. 1, Mansoura 35516, Egypt
| | - Teresa C. Cousin
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Johanna Hallenberger
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Filipe Rodrigues Almeida
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Max Anstötz
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Maximilian Lenz
- Institute of Neuroanatomy and Cell Biology, Hannover Medical School, Carl-Neuberg-Straße 1, 30625 Hannover, Germany;
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, 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;
| | - Charlotte von Gall
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
| | - Federica Tundo-Lavalle
- Institute of Anatomy II, Medical Faculty, Heinrich-Heine-University, Universitätsstraße 1, 40225 Düsseldorf, Germany; (J.K.S.); (L.A.-H.); (A.A.H.A.); (T.C.C.); (J.H.); (F.R.A.); (M.A.); (F.T.-L.)
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20
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Kang J, Lu N, Yang S, Guo B, Zhu Y, Wu S, Huang X, Wong-Riley MTT, Liu YY. Alterations in synapses and mitochondria induced by acute or chronic intermittent hypoxia in the pre-Bötzinger complex of rats: an ultrastructural triple-labeling study with immunocytochemistry and histochemistry. Front Cell Neurosci 2023; 17:1132241. [PMID: 37396926 PMCID: PMC10312010 DOI: 10.3389/fncel.2023.1132241] [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: 12/27/2022] [Accepted: 06/05/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction The pre-Bötzinger complex (pre-BötC), a kernel of inspiratory rhythmogenesis, is a heterogeneous network with excitatory glutamatergic and inhibitory GABAergic and glycinergic neurons. Inspiratory rhythm generation relies on synchronous activation of glutamatergic neuron, whilst inhibitory neurons play a critical role in shaping the breathing pattern, endowing the rhythm with flexibility in adapting to environmental, metabolic, and behavioral needs. Here we report ultrastructural alterations in excitatory, asymmetric synapses (AS) and inhibitory, symmetric synapses (SS), especially perforated synapses with discontinuous postsynaptic densities (PSDs) in the pre-BötC in rats exposed to daily acute intermittent hypoxia (dAIH) or chronic (C) IH. Methods We utilized for the first time a combination of somatostatin (SST) and neurokinin 1 receptor (NK1R) double immunocytochemistry with cytochrome oxidase histochemistry, to reveal synaptic characteristics and mitochondrial dynamic in the pre-BötC. Results We found perforated synapses with synaptic vesicles accumulated in distinct pools in apposition to each discrete PSD segments. dAIH induced significant increases in the PSD size of macular AS, and the proportion of perforated synapses. AS were predominant in the dAIH group, whereas SS were in a high proportion in the CIH group. dAIH significantly increased SST and NK1R expressions, whereas CIH led to a decrease. Desmosome-like contacts (DLC) were characterized for the first time in the pre-BötC. They were distributed alongside of synapses, especially SS. Mitochondria appeared in more proximity to DLC than synapses, suggestive of a higher energy demand of the DLC. Findings of single spines with dual AS and SS innervation provide morphological evidence of excitation-inhibition interplay within a single spine in the pre-BötC. In particular, we characterized spine-shaft microdomains of concentrated synapses coupled with mitochondrial positioning that could serve as a structural basis for synchrony of spine-shaft communication. Mitochondria were found within spines and ultrastructural features of mitochondrial fusion and fission were depicted for the first time in the pre-BötC. Conclusion We provide ultrastructural evidence of excitation-inhibition synapses in shafts and spines, and DLC in association with synapses that coincide with mitochondrial dynamic in their contribution to respiratory plasticity in the pre-BötC.
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Affiliation(s)
- Junjun Kang
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Naining Lu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Shoujing Yang
- Department of Pathology, The Fourth Military Medical University, Xi’an, China
| | - Baolin Guo
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Yuanyuan Zhu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Shengxi Wu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
| | - Xiaofeng Huang
- Department of Pathology, Xi’an Gaoxin Hospital, Xi’an, China
| | - Margaret T. T. Wong-Riley
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, WI, United States
| | - Ying-Ying Liu
- Department of Neurobiology, The Fourth Military Medical University, Xi’an, China
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21
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Fetterly TL, Catalfio AM, Ferrario CR. Effects of junk-food on food-motivated behavior and NAc glutamate plasticity; insights into the mechanism of NAc calcium-permeable AMPA receptor recruitment. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.16.540977. [PMID: 37292760 PMCID: PMC10245687 DOI: 10.1101/2023.05.16.540977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
In rats, eating obesogenic diets increase calcium-permeable AMPA receptor (CP-AMPAR) transmission in the nucleus accumbens (NAc) core, and enhances food-motivated behavior. Interestingly these diet-induced alterations in NAc transmission are pronounced in obesity-prone (OP) rats and absent in obesity-resistant (OR) populations. However, effects of diet manipulation on food motivation, and the mechanisms underlying NAc plasticity in OPs is unknown. Using male selectively-bred OP and OR rats, we assessed food-motivated behavior following ad lib access to chow (CH), junk-food (JF), or 10d of JF followed by a return to chow diet (JF-Dep). Behavioral tests included conditioned reinforcement, instrumental responding, and free consumption. Additionally, optogenetic, chemogenetic, and pharmacological approaches were used to examine NAc CP-AMPAR recruitment following diet manipulation and ex vivo treatment of brain slices. Motivation for food was greater in OP than OR rats, as expected. However, JF-Dep only produced enhancements in food-seeking in OP groups, while continuous JF access reduced food-seeking in both OPs and ORs. Reducing excitatory transmission in the NAc was sufficient to recruit CP-AMPARs to synapses in OPs, but not ORs. In OPs, JF-induced increases in CP-AMPARs occurred in mPFC-, but not BLA-to-NAc inputs. Diet differentially affects behavioral and neural plasticity in obesity susceptible populations. We also identify conditions for acute recruitment of NAc CP-AMPARs; these results suggest that synaptic scaling mechanisms contribute to NAc CP-AMPAR recruitment. Overall, this work improves our understanding of how sugary, fatty food consumption interacts with obesity susceptibility to influence food-motivated behavior. It also extends our fundamental understanding of NAc CP-AMPAR recruitment; this has important implications for motivation in the context of obesity as well as drug addiction.
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Affiliation(s)
- Tracy L. Fetterly
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Amanda M. Catalfio
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Carrie R. Ferrario
- Department of Pharmacology, University of Michigan, Ann Arbor, MI, 48109, USA
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22
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Kim JW, Suzuki K, Kavalali ET, Monteggia LM. Bridging rapid and sustained antidepressant effects of ketamine. Trends Mol Med 2023; 29:364-375. [PMID: 36907686 PMCID: PMC10101916 DOI: 10.1016/j.molmed.2023.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/05/2023] [Accepted: 02/15/2023] [Indexed: 03/12/2023]
Abstract
Acute administration of (R,S)-ketamine (ketamine) produces rapid antidepressant effects that in some patients can be sustained for several days to more than a week. Ketamine blocks N-methyl-d-asparate (NMDA) receptors (NMDARs) to elicit specific downstream signaling that induces a novel form of synaptic plasticity in the hippocampus that has been linked to the rapid antidepressant action. These signaling events lead to subsequent downstream transcriptional changes that are involved in the sustained antidepressant effects. Here we review how ketamine triggers this intracellular signaling pathway to mediate synaptic plasticity which underlies the rapid antidepressant effects and links it to downstream signaling and the sustained antidepressant effects.
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Affiliation(s)
- Ji-Woon Kim
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA; College of Pharmacy, Kyung Hee University, Seoul, Republic of Korea; Department of Regulatory Science, Gradaute School, Kyung Hee University, Seoul, Republic of Korea; Institute of Regulatory Innovation through Science, Kyung Hee University, Seoul, Republic of Korea
| | - Kanzo Suzuki
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA; Department of Biological Science and Technology, Faculty of Advanced Engineering, Tokyo University of Science, Katsushika-ku, Japan
| | - Ege T Kavalali
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA
| | - Lisa M Monteggia
- Department of Pharmacology and the Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37240, USA.
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23
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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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Zimbelman AR, Wong B, Murray CH, Wolf ME, Stefanik MT. Dopamine D1 and NMDA receptor co-regulation of protein translation in cultured nucleus accumbens neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.02.535293. [PMID: 37034633 PMCID: PMC10081306 DOI: 10.1101/2023.04.02.535293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
Abstract
Protein translation is essential for some forms of synaptic plasticity. We used nucleus accumbens (NAc) medium spiny neurons (MSN), co-cultured with cortical neurons to restore excitatory synapses, to examine whether dopamine modulates protein translation in NAc MSN. FUNCAT was used to measure translation in MSNs under basal conditions and after disinhibiting excitatory transmission using the GABAA receptor antagonist bicuculline (2 hr). Under basal conditions, translation was not altered by the D1-class receptor (D1R) agonist SKF81297 or the D2-class receptor (D2R) agonist quinpirole. Bicuculline alone robustly increased translation. This was reversed by quinpirole but not SKF81297. It was also reversed by co-incubation with the D1R antagonist SCH23390, but not the D2R antagonist eticlopride, suggesting dopaminergic tone at D1Rs. This was surprising because no dopamine neurons are present. An alternative explanation is that bicuculline activates translation by increasing glutamate tone at NMDA receptors (NMDAR) within D1R/NMDAR heteromers, which have been described in other cell types. Supporting this, immunocytochemistry and proximity ligation assays revealed D1/NMDAR heteromers on NAc cells both in vitro and in vivo. Further, bicuculline's effect was reversed to the same extent by SCH23390 alone, the NMDAR antagonist APV alone, or SCH23390+APV. These results suggest that: 1) excitatory synaptic transmission stimulates translation in NAc MSNs, 2) this is opposed when glutamate activates D1R/NMDAR heteromers, even in the absence of dopamine, and 3) antagonist occupation of D1Rs within the heteromers prevents their activation. Our study is the first to suggest a role for D2 receptors and D1R/NMDAR heteromers in regulating protein translation.
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Affiliation(s)
- Alexa R. Zimbelman
- Department of Psychology and Neuroscience, North Central College, Naperville, IL 60540
| | - Benjamin Wong
- Department of Psychology and Neuroscience, North Central College, Naperville, IL 60540
| | - Conor H. Murray
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064
- Present address: Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, IL
| | - Marina E. Wolf
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064
- These authors contributed equally
- Present address: Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97212
| | - Michael T. Stefanik
- Department of Psychology and Neuroscience, North Central College, Naperville, IL 60540
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064
- These authors contributed equally
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25
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Wagle S, Kraynyukova N, Hafner AS, Tchumatchenko T. Computational insights into mRNA and protein dynamics underlying synaptic plasticity rules. Mol Cell Neurosci 2023; 125:103846. [PMID: 36963534 DOI: 10.1016/j.mcn.2023.103846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 03/14/2023] [Accepted: 03/15/2023] [Indexed: 03/26/2023] Open
Abstract
Recent advances in experimental techniques provide an unprecedented peek into the intricate molecular dynamics inside synapses and dendrites. The experimental insights into the molecular turnover revealed that such processes as diffusion, active transport, spine uptake, and local protein synthesis could dynamically modulate the copy numbers of plasticity-related molecules in synapses. Subsequently, theoretical models were designed to understand the interaction of these processes better and to explain how local synaptic plasticity cues can up or down-regulate the molecular copy numbers across synapses. In this review, we discuss the recent advances in experimental techniques and computational models to highlight how these complementary approaches can provide insight into molecular cross-talk across synapses, ultimately allowing us to develop biologically-inspired neural network models to understand brain function.
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Affiliation(s)
- Surbhit Wagle
- Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Anselm-Franz-von-Bentzel-Weg 3, 55128 Mainz, Germany
| | - Nataliya Kraynyukova
- Institute of Experimental Epileptology and Cognition Research, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany
| | - Anne-Sophie Hafner
- Donders Institute for Brain, Cognition and Behaviour, Nijmegen, Netherlands; Faculty of Science, Radboud University, Nijmegen, Netherlands
| | - Tatjana Tchumatchenko
- Institute for Physiological Chemistry, University Medical Center of the Johannes Gutenberg-University Mainz, Anselm-Franz-von-Bentzel-Weg 3, 55128 Mainz, Germany; Institute of Experimental Epileptology and Cognition Research, University of Bonn, Venusberg-Campus 1, 53127 Bonn, Germany.
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26
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Naylor DE. In the fast lane: Receptor trafficking during status epilepticus. Epilepsia Open 2023; 8 Suppl 1:S35-S65. [PMID: 36861477 PMCID: PMC10173858 DOI: 10.1002/epi4.12718] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 02/23/2023] [Indexed: 03/03/2023] Open
Abstract
Status epilepticus (SE) remains a significant cause of morbidity and mortality and often is refractory to standard first-line treatments. A rapid loss of synaptic inhibition and development of pharmacoresistance to benzodiazepines (BZDs) occurs early during SE, while NMDA and AMPA receptor antagonists remain effective treatments after BZDs have failed. Multimodal and subunit-selective receptor trafficking within minutes to an hour of SE involves GABA-A, NMDA, and AMPA receptors and contributes to shifts in the number and subunit composition of surface receptors with differential impacts on the physiology, pharmacology, and strength of GABAergic and glutamatergic currents at synaptic and extrasynaptic sites. During the first hour of SE, synaptic GABA-A receptors containing γ2 subunits move to the cell interior while extrasynaptic GABA-A receptors with δ subunits are preserved. Conversely, NMDA receptors containing N2B subunits are increased at synaptic and extrasynaptic sites, and homomeric GluA1 ("GluA2-lacking") calcium permeant AMPA receptor surface expression also is increased. Molecular mechanisms, largely driven by NMDA receptor or calcium permeant AMPA receptor activation early during circuit hyperactivity, regulate subunit-specific interactions with proteins involved with synaptic scaffolding, adaptin-AP2/clathrin-dependent endocytosis, endoplasmic reticulum (ER) retention, and endosomal recycling. Reviewed here is how SE-induced shifts in receptor subunit composition and surface representation increase the excitatory to inhibitory imbalance that sustains seizures and fuels excitotoxicity contributing to chronic sequela such as "spontaneous recurrent seizures" (SRS). A role for early multimodal therapy is suggested both for treatment of SE and for prevention of long-term comorbidities.
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Affiliation(s)
- David E Naylor
- VA Greater Los Angeles Healthcare System, Department of Neurology, David Geffen School of Medicine at UCLA, and The Lundquist Institute at Harbor-UCLA Medical Center, Los Angeles, California, USA
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27
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Lv S, Yao K, Zhang Y, Zhu S. NMDA receptors as therapeutic targets for depression treatment: Evidence from clinical to basic research. Neuropharmacology 2023; 225:109378. [PMID: 36539011 DOI: 10.1016/j.neuropharm.2022.109378] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 12/08/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Abstract
Ketamine, functioning as a channel blocker of the excitatory glutamate-gated N-methyl-d-aspartate (NMDA) receptors, displays compelling fast-acting and sustained antidepressant effects for treatment-resistant depression. Over the past decades, clinical and preclinical studies have implied that the pathology of depression is associated with dysfunction of glutamatergic transmission. In particular, the discovery of antidepressant agents modulating NMDA receptor function has prompted breakthroughs for depression treatment compared with conventional antidepressants targeting the monoaminergic system. In this review, we first summarized the signalling pathway of the ketamine-mediated antidepressant effects, based on the glutamate hypothesis of depression. Second, we reviewed the hypotheses of the synaptic mechanism and network of ketamine antidepressant effects within different brain areas and distinct subcellular localizations, including NMDA receptor antagonism on GABAergic interneurons, extrasynaptic and synaptic NMDA receptor-mediated antagonism, and ketamine blocking bursting activities in the lateral habenula. Third, we reviewed the different roles of NMDA receptor subunits in ketamine-mediated cognitive and psychiatric behaviours in genetically-manipulated rodent models. Finally, we summarized the structural basis of NMDA receptor channel blockers and discussed NMDA receptor modulators that have been reported to exert potential antidepressant effects in animal models or in clinical trials. Integrating the cutting-edge technologies of cryo-EM and artificial intelligence-based drug design (AIDD), we expect that the next generation of first-in-class rapid antidepressants targeting NMDA receptors would be an emerging direction for depression therapeutics. This article is part of the Special Issue on 'Ketamine and its Metabolites'.
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Affiliation(s)
- Shiyun Lv
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China; University of Chinese Academy of Sciences, Beijing, China
| | - Kejie Yao
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China; University of Chinese Academy of Sciences, Beijing, China
| | - Youyi Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China; University of Chinese Academy of Sciences, Beijing, China
| | - Shujia Zhu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China; University of Chinese Academy of Sciences, Beijing, China.
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28
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Synaptotagmin 9 Modulates Spontaneous Neurotransmitter Release in Striatal Neurons by Regulating Substance P Secretion. J Neurosci 2023; 43:1475-1491. [PMID: 36732068 PMCID: PMC9992334 DOI: 10.1523/jneurosci.1857-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 01/05/2023] [Accepted: 01/10/2023] [Indexed: 02/04/2023] Open
Abstract
Synaptotagmin 9 (SYT9) is a tandem C2 domain Ca2+ sensor for exocytosis in neuroendocrine cells; its function in neurons remains unclear. Here, we show that, in mixed-sex cultures, SYT9 does not trigger rapid synaptic vesicle exocytosis in mouse cortical, hippocampal, or striatal neurons, unless it is massively overexpressed. In striatal neurons, loss of SYT9 reduced the frequency of spontaneous neurotransmitter release events (minis). We delved into the underlying mechanism and discovered that SYT9 was localized to dense-core vesicles that contain substance P (SP). Loss of SYT9 impaired SP release, causing the observed decrease in mini frequency. This model is further supported by loss of function mutants. Namely, Ca2+ binding to the C2A domain of SYT9 triggered membrane fusion in vitro, and mutations that disrupted this activity abolished the ability of SYT9 to regulate both SP release and mini frequency. We conclude that SYT9 indirectly regulates synaptic transmission in striatal neurons by controlling SP release.SIGNIFICANCE STATEMENT Synaptotagmin 9 (SYT9) has been described as a Ca2+ sensor for dense-core vesicle (DCV) exocytosis in neuroendocrine cells, but its role in neurons remains unclear, despite widespread expression in the brain. This article examines the role of SYT9 in synaptic transmission across cultured cortical, hippocampal, and striatal neuronal preparations. We found that SYT9 regulates spontaneous neurotransmitter release in striatal neurons by serving as a Ca2+ sensor for the release of the neuromodulator substance P from DCVs. This demonstrates a novel role for SYT9 in neurons and uncovers a new field of study into neuromodulation by SYT9, a protein that is widely expressed in the brain.
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29
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Bonifacino T, Mingardi J, Facchinetti R, Sala N, Frumento G, Ndoj E, Valenza M, Paoli C, Ieraci A, Torazza C, Balbi M, Guerinoni M, Muhammad N, Russo I, Milanese M, Scuderi C, Barbon A, Steardo L, Bonanno G, Popoli M, Musazzi L. Changes at glutamate tripartite synapses in the prefrontal cortex of a new animal model of resilience/vulnerability to acute stress. Transl Psychiatry 2023; 13:62. [PMID: 36806044 PMCID: PMC9938874 DOI: 10.1038/s41398-023-02366-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 02/20/2023] Open
Abstract
Stress represents a main risk factor for psychiatric disorders. Whereas it is known that even a single trauma may induce psychiatric disorders in humans, the mechanisms of vulnerability to acute stressors have been little investigated. In this study, we generated a new animal model of resilience/vulnerability to acute footshock (FS) stress in rats and analyzed early functional, molecular, and morphological determinants of stress vulnerability at tripartite glutamate synapses in the prefrontal cortex (PFC). We found that adult male rats subjected to FS can be deemed resilient (FS-R) or vulnerable (FS-V), based on their anhedonic phenotype 24 h after stress exposure, and that these two populations are phenotypically distinguishable up to two weeks afterwards. Basal presynaptic glutamate release was increased in the PFC of FS-V rats, while depolarization-evoked glutamate release and synapsin I phosphorylation at Ser9 were increased in both FS-R and FS-V. In FS-R and FS-V rats the synaptic expression of GluN2A and apical dendritic length of prelimbic PFC layers II-III pyramidal neurons were decreased, while BDNF expression was selectively reduced in FS-V. Depolarization-evoked (carrier-mediated) glutamate release from astroglia perisynaptic processes (gliosomes) was selectively increased in the PFC of FS-V rats, while GLT1 and xCt levels were higher and GS expression reduced in purified PFC gliosomes from FS-R. Overall, we show for the first time that the application of the sucrose intake test to rats exposed to acute FS led to the generation of a novel animal model of resilience/vulnerability to acute stress, which we used to identify early determinants of maladaptive response related to behavioral vulnerability to stress.
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Affiliation(s)
- Tiziana Bonifacino
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy
| | - Jessica Mingardi
- grid.7563.70000 0001 2174 1754School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy ,grid.7637.50000000417571846Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Roberta Facchinetti
- grid.7841.aDepartment of Physiology and Pharmacology “Vittorio Erspamer”, SAPIENZA University of Rome, Rome, Italy
| | - Nathalie Sala
- grid.4708.b0000 0004 1757 2822Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmaceutiche, Università Degli Studi di Milano, Milano, Italy
| | - Giulia Frumento
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy
| | - Elona Ndoj
- grid.7637.50000000417571846Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Marta Valenza
- grid.7841.aDepartment of Physiology and Pharmacology “Vittorio Erspamer”, SAPIENZA University of Rome, Rome, Italy
| | - Caterina Paoli
- grid.7563.70000 0001 2174 1754School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy ,grid.5602.10000 0000 9745 6549Pharmacology Unit, School of Pharmacy, University of Camerino, Camerino, Italy
| | - Alessandro Ieraci
- grid.4708.b0000 0004 1757 2822Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmaceutiche, Università Degli Studi di Milano, Milano, Italy ,grid.449889.00000 0004 5945 6678Department of Theoretical and Applied Sciences, eCampus University, Novedrate, Como, Italy
| | - Carola Torazza
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy
| | - Matilde Balbi
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy
| | - Michele Guerinoni
- grid.4708.b0000 0004 1757 2822Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmaceutiche, Università Degli Studi di Milano, Milano, Italy
| | - Nadeem Muhammad
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy
| | - Isabella Russo
- grid.7637.50000000417571846Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy ,Genetics Unit, IRCCS Istituto Centro S. Giovanni di Dio, Fatebenefratelli, 25125 Brescia, Italy
| | - Marco Milanese
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy ,grid.410345.70000 0004 1756 7871IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Caterina Scuderi
- grid.7841.aDepartment of Physiology and Pharmacology “Vittorio Erspamer”, SAPIENZA University of Rome, Rome, Italy
| | - Alessandro Barbon
- grid.7637.50000000417571846Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Luca Steardo
- grid.7841.aDepartment of Physiology and Pharmacology “Vittorio Erspamer”, SAPIENZA University of Rome, Rome, Italy
| | - Giambattista Bonanno
- grid.5606.50000 0001 2151 3065Department of Pharmacy, Unit of Pharmacology and Toxicology, University of Genoa, Genoa, Italy ,grid.410345.70000 0004 1756 7871IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Maurizio Popoli
- Laboratory of Neuropsychopharmacology and Functional Neurogenomics, Dipartimento di Scienze Farmaceutiche, Università Degli Studi di Milano, Milano, Italy.
| | - Laura Musazzi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
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30
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Abl2 Kinase Differentially Regulates iGluRs Current Activity and Synaptic Localization. Cell Mol Neurobiol 2023:10.1007/s10571-023-01317-9. [PMID: 36689065 DOI: 10.1007/s10571-023-01317-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 01/04/2023] [Indexed: 01/24/2023]
Abstract
Abelson non-receptor tyrosine kinases (Abl1 and Abl2) are established cellular signaling proteins, implicated in cytoskeletal reorganization essential for modulation of cell morphology and motility. During development of the central nervous system, Abl kinases play fundamental roles in neurulation and neurite outgrowth, relaying information from axon guidance cues and growth factor receptors to promote cytoskeletal rearrangements. In mature neurons, Abl kinases localize to pre- and postsynaptic compartments and are involved in regulation of synaptic stability and plasticity. Although emerging evidence indicates interchangeability of these isoforms in managing of cellular functions, in healthy adult neurons, Abl1 contribution is less elucidated, while Abl2 is required for optimal synaptic functioning. Our previous study demonstrated compartmentalization of Abl1 to the presynapse and Abl2 to the postsynapse and characterized their modulatory effect on spontaneous excitatory synaptic transmission. Here, we further delineate the role of Abl2 on regulation of the postsynaptic component of miniature excitatory postsynaptic current (mEPSC). Our findings show that both acute and prolonged activation of Abl2, in line with reduction of mEPSC amplitude, also decrease AMPA and NMDA current amplitudes. In contrast with the current-detrimental effect, prolonged Abl2 activity stabilizes spines, particularly contributing to maintenance of active synapses at distal (perhaps apical) segments of dendrites. Hence, we propose that attenuation of ion currents via ionotropic glutamatergic receptors by Abl2 kinase derives from either reduction of the receptor sensitivity for glutamate or is due to alteration of channel gating mechanisms. Abl2 and excitatory postsynapses: Abl2 expression level affects active excitatory synapse density on distal dendrites, while Abl2 activity impacts current density through AMPA and NMDA receptors.
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31
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Lee HK. Metaplasticity framework for cross-modal synaptic plasticity in adults. Front Synaptic Neurosci 2023; 14:1087042. [PMID: 36685084 PMCID: PMC9853192 DOI: 10.3389/fnsyn.2022.1087042] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/19/2022] [Indexed: 01/09/2023] Open
Abstract
Sensory loss leads to widespread adaptation of neural circuits to mediate cross-modal plasticity, which allows the organism to better utilize the remaining senses to guide behavior. While cross-modal interactions are often thought to engage multisensory areas, cross-modal plasticity is often prominently observed at the level of the primary sensory cortices. One dramatic example is from functional imaging studies in humans where cross-modal recruitment of the deprived primary sensory cortex has been observed during the processing of the spared senses. In addition, loss of a sensory modality can lead to enhancement and refinement of the spared senses, some of which have been attributed to compensatory plasticity of the spared sensory cortices. Cross-modal plasticity is not restricted to early sensory loss but is also observed in adults, which suggests that it engages or enables plasticity mechanisms available in the adult cortical circuit. Because adult cross-modal plasticity is observed without gross anatomical connectivity changes, it is thought to occur mainly through functional plasticity of pre-existing circuits. The underlying cellular and molecular mechanisms involve activity-dependent homeostatic and Hebbian mechanisms. A particularly attractive mechanism is the sliding threshold metaplasticity model because it innately allows neurons to dynamically optimize their feature selectivity. In this mini review, I will summarize the cellular and molecular mechanisms that mediate cross-modal plasticity in the adult primary sensory cortices and evaluate the metaplasticity model as an effective framework to understand the underlying mechanisms.
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32
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Lenz M, Eichler A, Kruse P, Stöhr P, Kleidonas D, Galanis C, Lu H, Vlachos A. Denervated mouse CA1 pyramidal neurons express homeostatic synaptic plasticity following entorhinal cortex lesion. Front Mol Neurosci 2023; 16:1148219. [PMID: 37122623 PMCID: PMC10130538 DOI: 10.3389/fnmol.2023.1148219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/14/2023] [Indexed: 05/02/2023] Open
Abstract
Structural, functional, and molecular reorganization of denervated neural networks is often observed in neurological conditions. The loss of input is accompanied by homeostatic synaptic adaptations, which can affect the reorganization process. A major challenge of denervation-induced homeostatic plasticity operating in complex neural networks is the specialization of neuronal inputs. It remains unclear whether neurons respond similarly to the loss of distinct inputs. Here, we used in vitro entorhinal cortex lesion (ECL) and Schaffer collateral lesion (SCL) in mouse organotypic entorhino-hippocampal tissue cultures to study denervation-induced plasticity of CA1 pyramidal neurons. We observed microglia accumulation, presynaptic bouton degeneration, and a reduction in dendritic spine numbers in the denervated layers 3 days after SCL and ECL. Transcriptome analysis of the CA1 region revealed complex changes in differential gene expression following SCL and ECL compared to non-lesioned controls with a specific enrichment of differentially expressed synapse-related genes observed after ECL. Consistent with this finding, denervation-induced homeostatic plasticity of excitatory synapses was observed 3 days after ECL but not after SCL. Chemogenetic silencing of the EC but not CA3 confirmed the pathway-specific induction of homeostatic synaptic plasticity in CA1. Additionally, increased RNA oxidation was observed after SCL and ECL. These results reveal important commonalities and differences between distinct pathway lesions and demonstrate a pathway-specific induction of denervation-induced homeostatic synaptic plasticity.
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Affiliation(s)
- Maximilian Lenz
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- *Correspondence: Maximilian Lenz,
| | - Amelie Eichler
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pia Kruse
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Phyllis Stöhr
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Dimitrios Kleidonas
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Christos Galanis
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Han Lu
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
| | - Andreas Vlachos
- Department of Neuroanatomy, Institute of Anatomy and Cell Biology, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Center BrainLinks-BrainTools, University of Freiburg, Freiburg, Germany
- Center for Basics in Neuromodulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Andreas Vlachos,
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Kavalali ET, Monteggia LM. Rapid homeostatic plasticity and neuropsychiatric therapeutics. Neuropsychopharmacology 2023; 48:54-60. [PMID: 35995973 PMCID: PMC9700859 DOI: 10.1038/s41386-022-01411-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/09/2022] [Accepted: 07/23/2022] [Indexed: 11/08/2022]
Abstract
Neuronal and synaptic plasticity are widely used terms in the field of psychiatry. However, cellular neurophysiologists have identified two broad classes of plasticity. Hebbian forms of plasticity alter synaptic strength in a synapse specific manner in the same direction of the initial conditioning stimulation. In contrast, homeostatic plasticities act globally over longer time frames in a negative feedback manner to counter network level changes in activity or synaptic strength. Recent evidence suggests that homeostatic plasticity mechanisms can be rapidly engaged, particularly by fast-acting antidepressants such as ketamine to trigger behavioral effects. There is increasing evidence that several neuropsychoactive compounds either directly elicit changes in synaptic activity or indirectly tap into downstream signaling pathways to trigger homeostatic plasticity and subsequent behavioral effects. In this review, we discuss this recent work in the context of a wider paradigm where homeostatic synaptic plasticity mechanisms may provide novel targets for neuropsychiatric 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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34
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Wang ZW, Riaz S, Niu L. Roles and Sources of Calcium in Synaptic Exocytosis. ADVANCES IN NEUROBIOLOGY 2023; 33:139-170. [PMID: 37615866 DOI: 10.1007/978-3-031-34229-5_6] [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: 08/25/2023]
Abstract
Calcium ions (Ca2+) play a critical role in triggering neurotransmitter release. The rate of release is directly related to the concentration of Ca2+ at the presynaptic site, with a supralinear relationship. There are two main sources of Ca2+ that trigger synaptic vesicle fusion: influx through voltage-gated Ca2+ channels in the plasma membrane and release from the endoplasmic reticulum via ryanodine receptors. This chapter will cover the sources of Ca2+ at the presynaptic nerve terminal, the relationship between neurotransmitter release rate and Ca2+ concentration, and the mechanisms that achieve the necessary Ca2+ concentrations for triggering synaptic exocytosis at the presynaptic site.
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Affiliation(s)
- Zhao-Wen Wang
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA.
| | - Sadaf Riaz
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
| | - Longgang Niu
- Department of Neuroscience, University of Connecticut School of Medicine, Farmington, CT, USA
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35
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Inouye MO, Colameo D, Ammann I, Winterer J, Schratt G. miR-329- and miR-495-mediated Prr7 down-regulation is required for homeostatic synaptic depression in rat hippocampal neurons. Life Sci Alliance 2022; 5:5/12/e202201520. [PMID: 36150742 PMCID: PMC9510147 DOI: 10.26508/lsa.202201520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 09/13/2022] [Accepted: 09/13/2022] [Indexed: 12/03/2022] Open
Abstract
In rat hippocampal neurons, miRNA-dependent regulation of the synaptic Prr7 protein is required for the homeostatic synaptic depression of excitatory synapses upstream of the CDK5-SPAR pathway. Homeostatic synaptic depression (HSD) in excitatory neurons is a cell-autonomous mechanism which protects excitatory neurons from over-excitation as a consequence of chronic increases in network activity. In this process, excitatory synapses are weakened and eventually eliminated, as evidenced by a reduction in synaptic AMPA receptor expression and dendritic spine loss. Originally considered a global, cell-wide mechanism, local forms of regulation, such as the local control of mRNA translation in dendrites, are being increasingly recognized in HSD. Yet, identification of excitatory proteins whose local regulation is required for HSD is still limited. Here, we show that proline-rich protein 7/transmembrane adapter protein 3 (Prr7) down-regulation in dendrites of rat hippocampal neurons is necessary for HSD induced by chronic increase in network activity resulting from a blockade of inhibitory synaptic transmission by picrotoxin (PTX). We further identify two activity-regulated miRNAs, miR-329-3p and miR-495-3p, which inhibit Prr7 mRNA translation and are required for HSD. Moreover, we found that Prr7 knockdown reduces expression of the synaptic scaffolding protein SPAR, which is rescued by pharmacological inhibition of CDK5, indicating a role of Prr7 protein in the maintenance of excitatory synapses via protection of SPAR from degradation. Together, our findings highlight a novel HSD mechanism in which chronic activity leads to miR-329– and miR-495–mediated Prr7 reduction upstream of the CDK5-SPAR pathway.
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Affiliation(s)
- Michiko O Inouye
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - David Colameo
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Irina Ammann
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Jochen Winterer
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
| | - Gerhard Schratt
- Department of Health Science and Technology, Laboratory of Systems Neuroscience, Institute for Neuroscience, Swiss Federal Institute of Technology ETH, Zürich, Switzerland
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36
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Cabrera OH, Useinovic N, Maksimovic S, Near M, Quillinan N, Todorovic SM, Jevtovic-Todorovic V. Neonatal ketamine exposure impairs infrapyramidal bundle pruning and causes lasting increase in excitatory synaptic transmission in hippocampal CA3 neurons. Neurobiol Dis 2022; 175:105923. [PMID: 36371060 PMCID: PMC9831613 DOI: 10.1016/j.nbd.2022.105923] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 10/27/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022] Open
Abstract
Preclinical models demonstrate that nearly all anesthetics cause widespread neuroapoptosis in the developing brains of infant rodents and non-human primates. Anesthesia-induced developmental apoptosis is succeeded by prolonged neuropathology in the surviving neurons and lasting cognitive impairments, suggesting that anesthetics interfere with the normal developmental trajectory of the brain. However, little is known about effects of anesthetics on stereotyped axonal pruning, an important developmental algorithm that sculpts neural circuits for proper function. Here, we proposed that neonatal ketamine exposure may interfere with stereotyped axonal pruning of the infrapyramidal bundle (IPB) of the hippocampal mossy fiber system and that impaired pruning may be associated with alterations in the synaptic transmission of CA3 neurons. To test this hypothesis, we injected postnatal day 7 (PND7) mouse pups with ketamine or vehicle over 6 h and then studied them at different developmental stages corresponding to IPB pruning (PND20-40). Immunohistochemistry with synaptoporin (a marker of mossy fibers) revealed that in juvenile mice treated with ketamine at PND7, but not in vehicle-treated controls, positive IPB fibers extended farther into the stratum pyramidale of CA3 region. Furthermore, immunofluorescent double labeling for synaptoporin and PSD-95 strongly suggested that the unpruned IPB caused by neonatal ketamine exposure makes functional synapses. Importantly, patch-clamp electrophysiology for miniature excitatory postsynaptic currents (mEPSCs) in acute brain slices ex vivo revealed increased frequency and amplitudes of mEPSCs in hippocampal CA3 neurons in ketamine-treated groups when compared to vehicle controls. We conclude that neonatal ketamine exposure interferes with normal neural circuit development and that this interference leads to lasting increase in excitatory synaptic transmission in hippocampus.
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Affiliation(s)
- Omar Hoseá Cabrera
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA
| | - Nemanja Useinovic
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA
| | - Stefan Maksimovic
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA
| | - Michelle Near
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA
| | - Nidia Quillinan
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA,University of Colorado School of Medicine at Anschutz Medical Campus, Neuroscience Graduate Program, Aurora, CO, USA
| | - Slobodan M. Todorovic
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA,University of Colorado School of Medicine at Anschutz Medical Campus, Neuroscience Graduate Program, Aurora, CO, USA
| | - Vesna Jevtovic-Todorovic
- University of Colorado School of Medicine at Anschutz Medical Campus, Department of Anesthesiology, Aurora, CO, USA,University of Colorado School of Medicine at Anschutz Medical Campus, Department of Pharmacology, Aurora, CO, USA,Corresponding author. (V. Jevtovic-Todorovic)
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37
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The neuroprotective and neuroplastic potential of glutamatergic therapeutic drugs in bipolar disorder. Neurosci Biobehav Rev 2022; 142:104906. [DOI: 10.1016/j.neubiorev.2022.104906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/30/2022] [Accepted: 10/02/2022] [Indexed: 11/21/2022]
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38
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Colameo D, Schratt G. Synaptic tagging: homeostatic plasticity goes Hebbian. EMBO J 2022; 41:e112383. [PMID: 36097740 PMCID: PMC9574739 DOI: 10.15252/embj.2022112383] [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: 08/16/2022] [Accepted: 08/29/2022] [Indexed: 11/09/2022] Open
Abstract
Distinct plasticity mechanisms enable neurons to effectively process information also when facing global perturbations in network activity. In this issue of The EMBO Journal, Dubes et al (2022) provide a molecular mechanism whereby individual synapses during periods of chronic inactivity are "tagged" for future strengthening. These results lend further support to the idea that local, nonmultiplicative mechanisms play an important role in homeostatic synaptic plasticity as has been demonstrated for Hebbian-like synaptic plasticity.
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Affiliation(s)
- David Colameo
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and TechnologySwiss Federal Institute of Technology ETHZürichSwitzerland
| | - Gerhard Schratt
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and TechnologySwiss Federal Institute of Technology ETHZürichSwitzerland
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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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40
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Tian H, Hu Z, Xu J, Wang C. The molecular pathophysiology of depression and the new therapeutics. MedComm (Beijing) 2022; 3:e156. [PMID: 35875370 PMCID: PMC9301929 DOI: 10.1002/mco2.156] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 06/06/2022] [Accepted: 06/06/2022] [Indexed: 12/21/2022] Open
Abstract
Major depressive disorder (MDD) is a highly prevalent and disabling disorder. Despite the many hypotheses proposed to understand the molecular pathophysiology of depression, it is still unclear. Current treatments for depression are inadequate for many individuals, because of limited effectiveness, delayed efficacy (usually two weeks), and side effects. Consequently, novel drugs with increased speed of action and effectiveness are required. Ketamine has shown to have rapid, reliable, and long-lasting antidepressant effects in treatment-resistant MDD patients and represent a breakthrough therapy for patients with MDD; however, concerns regarding its efficacy, potential misuse, and side effects remain. In this review, we aimed to summarize molecular mechanisms and pharmacological treatments for depression. We focused on the fast antidepressant treatment and clarified the safety, tolerability, and efficacy of ketamine and its metabolites for the MDD treatment, along with a review of the potential pharmacological mechanisms, research challenges, and future clinical prospects.
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Affiliation(s)
- Haihua Tian
- Ningbo Key Laboratory of Behavioral Neuroscience Ningbo University School of Medicine Ningbo Zhejiang China.,Zhejiang Provincial Key Laboratory of Pathophysiology School of Medicine Ningbo University Ningbo Zhejiang China.,Department of Physiology and Pharmacology Ningbo University School of Medicine Ningbo Zhejiang China.,Department of Laboratory Medicine Ningbo Kangning Hospital Ningbo Zhejiang China
| | - Zhenyu Hu
- Department of Child Psychiatry Ningbo Kanning Hospital Ningbo Zhejiang China
| | - Jia Xu
- Ningbo Key Laboratory of Behavioral Neuroscience Ningbo University School of Medicine Ningbo Zhejiang China.,Zhejiang Provincial Key Laboratory of Pathophysiology School of Medicine Ningbo University Ningbo Zhejiang China.,Department of Physiology and Pharmacology Ningbo University School of Medicine Ningbo Zhejiang China
| | - Chuang Wang
- Ningbo Key Laboratory of Behavioral Neuroscience Ningbo University School of Medicine Ningbo Zhejiang China.,Zhejiang Provincial Key Laboratory of Pathophysiology School of Medicine Ningbo University Ningbo Zhejiang China.,Department of Physiology and Pharmacology Ningbo University School of Medicine Ningbo Zhejiang China
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41
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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: 7] [Impact Index Per Article: 3.5] [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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Bülow P, Segal M, Bassell GJ. Mechanisms Driving the Emergence of Neuronal Hyperexcitability in Fragile X Syndrome. Int J Mol Sci 2022; 23:ijms23116315. [PMID: 35682993 PMCID: PMC9181819 DOI: 10.3390/ijms23116315] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Revised: 05/24/2022] [Accepted: 05/27/2022] [Indexed: 02/04/2023] Open
Abstract
Hyperexcitability is a shared neurophysiological phenotype across various genetic neurodevelopmental disorders, including Fragile X syndrome (FXS). Several patient symptoms are associated with hyperexcitability, but a puzzling feature is that their onset is often delayed until their second and third year of life. It remains unclear how and why hyperexcitability emerges in neurodevelopmental disorders. FXS is caused by the loss of FMRP, an RNA-binding protein which has many critical roles including protein synthesis-dependent and independent regulation of ion channels and receptors, as well as global regulation of protein synthesis. Here, we discussed recent literature uncovering novel mechanisms that may drive the progressive onset of hyperexcitability in the FXS brain. We discussed in detail how recent publications have highlighted defects in homeostatic plasticity, providing new insight on the FXS brain and suggest pharmacotherapeutic strategies in FXS and other neurodevelopmental disorders.
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Affiliation(s)
- Pernille Bülow
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence: (P.B.); (G.J.B.)
| | - Menahem Segal
- Department of Brain Science, Weizmann Institute of Science, Rehovot 76100, Israel;
| | - Gary J. Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
- Correspondence: (P.B.); (G.J.B.)
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43
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Search for Selective Glua1 Ampa Receptor Antagonists in a Series of Dicationic Compounds. Pharm Chem J 2022. [DOI: 10.1007/s11094-022-02635-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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44
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Egashira Y, Kumade A, Ojida A, Ono F. Spontaneously Recycling Synaptic Vesicles Constitute Readily Releasable Vesicles in Intact Neuromuscular Synapses. J Neurosci 2022; 42:3523-3536. [PMID: 35332083 PMCID: PMC9053852 DOI: 10.1523/jneurosci.2005-21.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Revised: 03/08/2022] [Accepted: 03/10/2022] [Indexed: 12/14/2022] Open
Abstract
Emerging evidence shows that spontaneous synaptic transmission plays crucial roles on neuronal functions through presynaptic molecular mechanisms distinct from that of action potential (AP)-evoked transmission. However, whether the synaptic vesicle (SV) population undergoing the two forms of transmission is segregated remains controversial due in part to the conflicting results observed in cultured neurons. Here we address this issue in intact neuromuscular synapses using transgenic zebrafish larvae expressing two different indicators targeted in the SVs: a pH-sensitive fluorescent protein, pHluorin, and a tag protein, HaloTag. By establishing a quantitative measure of recycled SV fractions, we found that ∼85% of SVs were mobilized by high-frequency AP firings. In contrast, spontaneously recycling SVs were mobilized only from <8% of SVs with a time constant of 45 min at 25°C, although prolonged AP inhibition mobilized an additional population with a delayed onset. The mobilization of the early-onset population was less temperature-sensitive and resistant to tetanus toxin, whereas that of the late-onset population was more sensitive to temperature and was inhibited by tetanus toxin, indicating that prolonged AP inhibition activated a distinct molecular machinery for spontaneous SV fusion. Therefore, the early-onset population limited to <8% was likely the only source of spontaneous release that occurred physiologically. We further showed that this limited population was independent from those reluctant to fuse during AP firing and was used in both the hypertonic stimulation and the immediate phase of AP-evoked releases, thereby matching the characteristics of the readily releasable pool.SIGNIFICANCE STATEMENT Synaptic vesicles (SVs) are divided into functionally distinct pools depending on how they respond to action potential (AP) firing. The origin of SVs used for spontaneous fusion remains enigmatic despite intensive studies in cultured preparations. We addressed this question in intact neuromuscular synapses and provided two findings. First, prolonged AP inhibition activated a distinct population of fusion, which needs to be distinguished from genuine spontaneous fusion arising from a highly limited fraction. Second, the limited fraction observed early in the AP inhibition period exhibited the characteristics of readily releasable pool in the subsequent round of stimulation. Our study revealed that the origin of spontaneous SV fusion is restricted to the readily releasable pool among the SV pools involved in AP-evoked fusion.
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Affiliation(s)
- Yoshihiro Egashira
- Department of Physiology, Osaka Medical and Pharmaceutical University, Takatsuki, 569-8686, Japan
| | - Ayane Kumade
- Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Akio Ojida
- Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Fumihito Ono
- Department of Physiology, Osaka Medical and Pharmaceutical University, Takatsuki, 569-8686, Japan
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Sancho-Alonso M, Taoro-Gonzalez L, Cabrera-Pastor A, Felipo V, Teruel-Martí V. Hyperammonemia Alters the Function of AMPA and NMDA Receptors in Hippocampus: Extracellular cGMP Reverses Some of These Alterations. Neurochem Res 2022; 47:2016-2031. [PMID: 35386048 DOI: 10.1007/s11064-022-03588-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/17/2022] [Accepted: 03/20/2022] [Indexed: 11/25/2022]
Abstract
Chronic hyperammonemia alters membrane expression of AMPA and NMDA receptors subunits in hippocampus leading to impaired memory and learning. Increasing extracellular cGMP normalizes these alterations. However, it has not been studied whether hyperammonemia alters the function of AMPA and NMDA receptors. The aims of this work were: (1) assess if hyperammonemia alters AMPA and NMDA receptors function; (2) analyze if extracellular cGMP reverses these alterations. A multielectrode array device was used to stimulate Schäffer collaterals and record postsynaptic currents in the CA1 region in hippocampal slices from control and hyperammonemic rats and analyze different features of the excitatory postsynaptic potentials. Hyperammonemia reduces the amplitude and delays appearance of AMPA EPSPs, whereas increases amplitude, hyperpolarization, depolarization and desensitization area of the NMDA EPSPs. These alterations in AMPA and NMDA function are accentuated as the stimulation intensity increases. Adding extracellular cGMP reverses the alteration in amplitude in both, AMPA and NMDA EPSPs. In control slices extracellular cGMP decreases the AMPA and NMDA EPSPs amplitude and delays the response of neurons and the return to the resting potential at all stimulation intensities. In conclusion, hyperammonemia decreases the AMPA response, whereas increases the NMDA response and extracellular cGMP reverses these alterations.
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Affiliation(s)
- María Sancho-Alonso
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012, Valencia, Spain
| | - Lucas Taoro-Gonzalez
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012, Valencia, Spain
| | - Andrea Cabrera-Pastor
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012, Valencia, Spain.,Fundación Investigación Hospital Clínico, Instituto de Investigación Sanitaria (INCLIVA), 46010, Valencia, Spain
| | - Vicente Felipo
- Laboratory of Neurobiology, Centro de Investigación Príncipe Felipe, 46012, Valencia, Spain.
| | - Vicent Teruel-Martí
- Anatomy and Human Embryology Department, Faculty of Medicine, University of Valencia, 46010, Valencia, Spain
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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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Wang YT, Zhang NN, Liu LJ, Jiang H, Hu D, Wang ZZ, Chen NH, Zhang Y. Glutamatergic receptor and neuroplasticity in depression: Implications for ketamine and rapastinel as the rapid-acting antidepressants. Biochem Biophys Res Commun 2022; 594:46-56. [DOI: 10.1016/j.bbrc.2022.01.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 12/21/2021] [Accepted: 01/08/2022] [Indexed: 12/11/2022]
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Guzikowski NJ, Kavalali ET. Nano-Organization at the Synapse: Segregation of Distinct Forms of Neurotransmission. Front Synaptic Neurosci 2022; 13:796498. [PMID: 35002671 PMCID: PMC8727373 DOI: 10.3389/fnsyn.2021.796498] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Accepted: 11/19/2021] [Indexed: 01/01/2023] Open
Abstract
Synapses maintain synchronous, asynchronous, and spontaneous modes of neurotransmission through distinct molecular and biochemical pathways. Traditionally a single synapse was assumed to have a homogeneous organization of molecular components both at the active zone and post-synaptically. However, recent advancements in experimental tools and the further elucidation of the physiological significance of distinct forms of release have challenged this notion. In comparison to rapid evoked release, the physiological significance of both spontaneous and asynchronous neurotransmission has only recently been considered in parallel with synaptic structural organization. Active zone nanostructure aligns with postsynaptic nanostructure creating a precise trans-synaptic alignment of release sites and receptors shaping synaptic efficacy, determining neurotransmission reliability, and tuning plasticity. This review will discuss how studies delineating synaptic nanostructure create a picture of a molecularly heterogeneous active zone tuned to distinct forms of release that may dictate diverse synaptic functional outputs.
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Affiliation(s)
- Natalie J Guzikowski
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
| | - Ege T Kavalali
- Department of Pharmacology, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN, United States
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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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50
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Mitchell GS, Baker TL. Respiratory neuroplasticity: Mechanisms and translational implications of phrenic motor plasticity. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:409-432. [PMID: 35965036 DOI: 10.1016/b978-0-323-91534-2.00016-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Widespread appreciation that neuroplasticity is an essential feature of the neural system controlling breathing has emerged only in recent years. In this chapter, we focus on respiratory motor plasticity, with emphasis on the phrenic motor system. First, we define related but distinct concepts: neuromodulation and neuroplasticity. We then focus on mechanisms underlying two well-studied models of phrenic motor plasticity: (1) phrenic long-term facilitation following brief exposure to acute intermittent hypoxia; and (2) phrenic motor facilitation after prolonged or recurrent bouts of diminished respiratory neural activity. Advances in our understanding of these novel and important forms of plasticity have been rapid and have already inspired translation in multiple respects: (1) development of novel therapeutic strategies to preserve/restore breathing function in humans with severe neurological disorders, such as spinal cord injury and amyotrophic lateral sclerosis; and (2) the discovery that similar plasticity also occurs in nonrespiratory motor systems. Indeed, the realization that similar plasticity occurs in respiratory and nonrespiratory motor neurons inspired clinical trials to restore leg/walking and hand/arm function in people living with chronic, incomplete spinal cord injury. Similar application may be possible to other clinical disorders that compromise respiratory and non-respiratory movements.
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Affiliation(s)
- Gordon S Mitchell
- Breathing Research and Therapeutics Center, Department of Physical Therapy and McKnight Brain Institute, University of Florida, Gainesville, FL, United States.
| | - Tracy L Baker
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, WI, United States
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