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Trujillo-Estrada L, Vanderklish PW, Nguyen MMT, Kuang RR, Nguyen C, Huynh E, da Cunha C, Javonillo DI, Forner S, Martini AC, Sarraf ST, Simmon VF, Baglietto-Vargas D, LaFerla FM. SPG302 Reverses Synaptic and Cognitive Deficits Without Altering Amyloid or Tau Pathology in a Transgenic Model of Alzheimer's Disease. Neurotherapeutics 2021; 18:2468-2483. [PMID: 34738197 PMCID: PMC8804111 DOI: 10.1007/s13311-021-01143-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/11/2021] [Indexed: 12/04/2022] Open
Abstract
Alzheimer's disease (AD) is conceptualized as a synaptic failure disorder in which loss of glutamatergic synapses is a major driver of cognitive decline. Thus, novel therapeutic strategies aimed at regenerating synapses may represent a promising approach to mitigate cognitive deficits in AD patients. At present, no disease-modifying drugs exist for AD, and approved therapies are palliative at best, lacking in the ability to reverse the synaptic failure. Here, we tested the efficacy of a novel synaptogenic small molecule, SPG302 - a 3rd-generation benzothiazole derivative that increases the density of axospinous glutamatergic synapses - in 3xTg-AD mice. Daily dosing of 3xTg-AD mice with SPG302 at 3 and 30 mg/kg (i.p.) for 4 weeks restored hippocampal synaptic density and improved cognitive function in hippocampal-dependent tasks. Mushroom and stubby spine profiles were increased by SPG302, and associated with enhanced expression of key postsynaptic proteins - including postsynaptic density protein 95 (PSD95), drebrin, and amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) - and increased colocalization of PSD95 with synaptophysin. Notably, SPG302 proved efficacious in this model without modifying Aβ and tau pathology. Thus, our study provides preclinical support for the idea that compounds capable of restoring synaptic density offer a viable strategy to reverse cognitive decline in AD.
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Affiliation(s)
- Laura Trujillo-Estrada
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
- Departamento Biología Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, Malaga, Spain
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain
| | - Peter W Vanderklish
- Spinogenix Inc, 10210 Campus Point Drive, Suite 150, San Diego, CA, 92121, USA.
| | - Marie Minh Thu Nguyen
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Run Rong Kuang
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Caroline Nguyen
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Eric Huynh
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Celia da Cunha
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Dominic Ibarra Javonillo
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Stefania Forner
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Alessandra C Martini
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA
| | - Stella T Sarraf
- Spinogenix Inc, 10210 Campus Point Drive, Suite 150, San Diego, CA, 92121, USA
| | - Vincent F Simmon
- Spinogenix Inc, 10210 Campus Point Drive, Suite 150, San Diego, CA, 92121, USA.
| | - David Baglietto-Vargas
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA.
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-1450, USA.
- Departamento Biología Celular, Genetica y Fisiologia, Instituto de Investigacion Biomedica de Malaga-IBIMA, Facultad de Ciencias, Universidad de Malaga, Malaga, Spain.
- Centro de Investigacion Biomedica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Madrid, Spain.
| | - Frank M LaFerla
- Institute for Memory Impairments and Neurological Disorders, University of California, Irvine, CA, 92697, USA.
- Department of Neurobiology and Behavior, University of California, Irvine, CA, 92697-1450, USA.
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52
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Laviv T, Yasuda R. Imaging neuronal protein signaling dynamics in vivo. Curr Opin Neurobiol 2021; 69:68-75. [PMID: 33684848 PMCID: PMC8387335 DOI: 10.1016/j.conb.2021.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/31/2021] [Accepted: 02/05/2021] [Indexed: 11/16/2022]
Abstract
The activity patterns of Individual neurons are highly coordinated and synchronized within neuronal circuits in the brain, much like individual orchestra tools playing together to achieve harmony. Inside neurons, complex protein signaling cascades provide the molecular notes and instructions to each neuron. However, until recently, the dynamic nature of intracellular protein signaling in the intact brain has been eluded. In this review, we focus on recent advancements and the development of approaches to study neuronal signaling dynamics in vivo. We will discuss approaches for the implementation of biosensors for monitoring of protein signaling activities at the levels of individual synapses, dendritic branches, cell-wide neuromodulation, and transcription in the nucleus. Future improvement in these methods and their utilization will undoubtedly yield new insights regarding the intricate link between functional and molecular neuronal dynamics and how they underlie animal's behavior.
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Affiliation(s)
- Tal Laviv
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel; Sagol School of Neuroscience, Tel Aviv University, 69978 Tel Aviv, Israel.
| | - Ryohei Yasuda
- Department of Neuronal Signal Transduction, Max Planck Institute for Neuroscience, Jupiter, FL, 33458, USA.
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53
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Gemin O, Serna P, Zamith J, Assendorp N, Fossati M, Rostaing P, Triller A, Charrier C. Unique properties of dually innervated dendritic spines in pyramidal neurons of the somatosensory cortex uncovered by 3D correlative light and electron microscopy. PLoS Biol 2021; 19:e3001375. [PMID: 34428203 PMCID: PMC8415616 DOI: 10.1371/journal.pbio.3001375] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 09/03/2021] [Accepted: 07/29/2021] [Indexed: 01/04/2023] Open
Abstract
Pyramidal neurons (PNs) are covered by thousands of dendritic spines receiving excitatory synaptic inputs. The ultrastructure of dendritic spines shapes signal compartmentalization, but ultrastructural diversity is rarely taken into account in computational models of synaptic integration. Here, we developed a 3D correlative light-electron microscopy (3D-CLEM) approach allowing the analysis of specific populations of synapses in genetically defined neuronal types in intact brain circuits. We used it to reconstruct segments of basal dendrites of layer 2/3 PNs of adult mouse somatosensory cortex and quantify spine ultrastructural diversity. We found that 10% of spines were dually innervated and 38% of inhibitory synapses localized to spines. Using our morphometric data to constrain a model of synaptic signal compartmentalization, we assessed the impact of spinous versus dendritic shaft inhibition. Our results indicate that spinous inhibition is locally more efficient than shaft inhibition and that it can decouple voltage and calcium signaling, potentially impacting synaptic plasticity.
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Affiliation(s)
- Olivier Gemin
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Pablo Serna
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
- Laboratoire de Physique de l’Ecole Normale Supérieure, ENS, PSL Research University, CNRS, Sorbonne Université, Université Paris-Diderot, Sorbonne Paris Cité, Paris, France
| | - Joseph Zamith
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Nora Assendorp
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Matteo Fossati
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Philippe Rostaing
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Antoine Triller
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
| | - Cécile Charrier
- Institut de Biologie de l’Ecole Normale Supérieure (IBENS), CNRS, INSERM, PSL Research University, Paris, France
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González-Martín A, Moyano T, Gutiérrez DA, Carvajal FJ, Cerpa W, Hanley JG, Gutiérrez RA, Álvarez AR. c-Abl regulates a synaptic plasticity-related transcriptional program involved in memory and learning. Prog Neurobiol 2021; 205:102122. [PMID: 34284000 DOI: 10.1016/j.pneurobio.2021.102122] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 11/20/2022]
Abstract
Memory consolidation requires activation of a gene expression program that allows de novo protein synthesis. But the molecular mechanisms that favour or restrict that program are poorly understood. The kinase c-Abl can modulate gene expression through transcription factors and chromatin modifiers. Here, we show that c-Abl ablation in the brain improves learning acquisition and memory consolidation in mice. Its absence also affects gene expression profiles in the mouse hippocampus. We found that genes involved in synaptic plasticity and actin cytoskeleton dynamics, such as Arp2 and Thorase, are up-regulated at the mRNA and protein levels in trained c-Abl KO mice and by a chemical-LTP stimulus. Trained c-Abl KO mice also show that dendritic spines are larger than in wild-type mice and present at a higher density. These results indicate that c-Abl kinase is an important part of the mechanism that limits or restricts signalling of relevant gene programs involved in morphological and functional spine changes upon neuronal stimulation.
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Affiliation(s)
- Adrián González-Martín
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile; Centre for Aging and Regeneration (CARE-UC), Chile
| | - Tomás Moyano
- FONDAP Center for Genome Regulation, Millennium Institute for Integrative Biology (iBio), Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avda. Libertador Bernardo O'Higgins 340, Santiago, 8331150, Chile
| | - Daniela A Gutiérrez
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile; Centre for Aging and Regeneration (CARE-UC), Chile
| | - Franciso J Carvajal
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile; Center of Excellence in Biomedicine of Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - Waldo Cerpa
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile; Centre for Aging and Regeneration (CARE-UC), Chile; Center of Excellence in Biomedicine of Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile
| | - Jonathan G Hanley
- Centre for Synaptic Plasticity and School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK
| | - Rodrigo A Gutiérrez
- FONDAP Center for Genome Regulation, Millennium Institute for Integrative Biology (iBio), Department of Molecular Genetics and Microbiology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avda. Libertador Bernardo O'Higgins 340, Santiago, 8331150, Chile
| | - Alejandra R Álvarez
- Department of Cell & Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Santiago de Chile, Chile; Centre for Aging and Regeneration (CARE-UC), Chile.
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55
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Kasai H, Ziv NE, Okazaki H, Yagishita S, Toyoizumi T. Spine dynamics in the brain, mental disorders and artificial neural networks. Nat Rev Neurosci 2021; 22:407-422. [PMID: 34050339 DOI: 10.1038/s41583-021-00467-3] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2021] [Indexed: 12/15/2022]
Abstract
In the brain, most synapses are formed on minute protrusions known as dendritic spines. Unlike their artificial intelligence counterparts, spines are not merely tuneable memory elements: they also embody algorithms that implement the brain's ability to learn from experience and cope with new challenges. Importantly, they exhibit structural dynamics that depend on activity, excitatory input and inhibitory input (synaptic plasticity or 'extrinsic' dynamics) and dynamics independent of activity ('intrinsic' dynamics), both of which are subject to neuromodulatory influences and reinforcers such as dopamine. Here we succinctly review extrinsic and intrinsic dynamics, compare these with parallels in machine learning where they exist, describe the importance of intrinsic dynamics for memory management and adaptation, and speculate on how disruption of extrinsic and intrinsic dynamics may give rise to mental disorders. Throughout, we also highlight algorithmic features of spine dynamics that may be relevant to future artificial intelligence developments.
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Affiliation(s)
- Haruo Kasai
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan. .,International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
| | - Noam E Ziv
- Technion Faculty of Medicine and Network Biology Research Labs, Technion City, Haifa, Israel
| | - Hitoshi Okazaki
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.,International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Sho Yagishita
- Laboratory of Structural Physiology, Center for Disease Biology and Integrative Medicine, Faculty of Medicine, The University of Tokyo, Tokyo, Japan.,International Research Center for Neurointelligence (WPI-IRCN), UTIAS, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Taro Toyoizumi
- Laboratory for Neural Computation and Adaptation, RIKEN Center for Brain Science, Saitama, Japan.,Department of Mathematical Informatics, Graduate School of Information Science and Technology, The University of Tokyo, Tokyo, Japan
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56
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Lippman-Bell JJ, Handy M, Nieder CG, Getzfread M, Jensen FE. Altered hippocampal dendritic spine maturation after hypoxia-induced seizures in neonatal rats. Mol Cell Neurosci 2021; 113:103629. [PMID: 34015497 DOI: 10.1016/j.mcn.2021.103629] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 05/10/2021] [Accepted: 05/12/2021] [Indexed: 12/01/2022] Open
Abstract
Cognitive comorbidities often follow early-life seizures (ELS), especially in the setting of autism and other neurodevelopmental syndromes. However, there is an incomplete understanding of whether neuronal and synaptic development are concomitantly dysregulated. We have previously shown that hypoxia-induced seizures (HS) in postnatal day (P)10 rats increase acute and later-life hippocampal glutamatergic neurotransmission and spontaneous recurrent seizures, and impair cognition and behavior. As dendritic spines critically regulate synaptic function, we hypothesized that ELS can induce developmentally specific changes in dendritic spine maturation. At intervals during one month following HS in P10 rats, we assessed dendritic spine development on pyramidal neurons in the stratum radiatum of hippocampal area CA1. Compared to control rats in which spine density significantly decreased from P10 to early adulthood (P38), post-seizure rats failed to show a developmental decrease in spine density, and spines from P38 post-seizure rats appeared more immature-shaped (long, thin). In addition, compared to P38 control rats, post-seizure P38 rats expressed significantly more synaptic PSD-95, a marker of mature synapses. These changes were preceded by a transient increase in hippocampal expression of cofilin phosphorylated at Ser3, representing a decrease in cofilin activity. These results suggest that early-life seizures may impair normal dendritic spine maturation and pruning in CA1 during development, resulting in an excess of less efficient synapses, via activity-dependent modification of actin-regulating proteins such as cofilin. Given that multiple neurodevelopmental disorders show similar failures in developmental spine pruning, the current findings may represent a deficit in structural plasticity that could be a component of a mechanism leading to later-life cognitive consequences associated with early-life seizures.
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Affiliation(s)
- Jocelyn J Lippman-Bell
- Department of Biomedical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States of America; Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America.
| | - Marcus Handy
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America
| | - Cassidy G Nieder
- Department of Biomedical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States of America
| | - Mollie Getzfread
- Department of Biomedical Sciences, Philadelphia College of Osteopathic Medicine, Philadelphia, PA, United States of America
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States of America.
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57
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Holderith N, Heredi J, Kis V, Nusser Z. A High-Resolution Method for Quantitative Molecular Analysis of Functionally Characterized Individual Synapses. Cell Rep 2021; 32:107968. [PMID: 32726631 PMCID: PMC7408500 DOI: 10.1016/j.celrep.2020.107968] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/15/2020] [Accepted: 07/08/2020] [Indexed: 12/24/2022] Open
Abstract
Elucidating the molecular mechanisms underlying the functional diversity of synapses requires a high-resolution, sensitive, diffusion-free, quantitative localization method that allows the determination of many proteins in functionally characterized individual synapses. Array tomography permits the quantitative analysis of single synapses but has limited sensitivity, and its application to functionally characterized synapses is challenging. Here, we aim to overcome these limitations by searching the parameter space of different fixation, resin, embedding, etching, retrieval, and elution conditions. Our optimizations reveal that etching epoxy-resin-embedded ultrathin sections with Na-ethanolate and treating them with SDS dramatically increase the labeling efficiency of synaptic proteins. We also demonstrate that this method is ideal for the molecular characterization of individual synapses following paired recordings, two-photon [Ca2+] or glutamate-sensor (iGluSnFR) imaging. This method fills a missing gap in the toolbox of molecular and cellular neuroscience, helping us to reveal how molecular heterogeneity leads to diversity in function. Etching and antigen retrieval enhance immunoreactions in epoxy-resin-embedded tissue Biocytin-filled nerve cells can be visualized in epoxy-resin-embedded tissue Molecular composition of functionally characterized individual synapses is revealed Multiplexed, postembedding reactions are compatible with STED imaging
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Affiliation(s)
- Noemi Holderith
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest 1083, Hungary
| | - Judit Heredi
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest 1083, Hungary
| | - Viktor Kis
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest 1083, Hungary
| | - Zoltan Nusser
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest 1083, Hungary.
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58
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Karlocai MR, Heredi J, Benedek T, Holderith N, Lorincz A, Nusser Z. Variability in the Munc13-1 content of excitatory release sites. eLife 2021; 10:67468. [PMID: 33904397 PMCID: PMC8116053 DOI: 10.7554/elife.67468] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/26/2021] [Indexed: 01/15/2023] Open
Abstract
The molecular mechanisms underlying the diversity of cortical glutamatergic synapses are still incompletely understood. Here, we tested the hypothesis that presynaptic active zones (AZs) are constructed from molecularly uniform, independent release sites (RSs), the number of which scales linearly with the AZ size. Paired recordings between hippocampal CA1 pyramidal cells and fast-spiking interneurons in acute slices from adult mice followed by quantal analysis demonstrate large variability in the number of RSs (N) at these connections. High-resolution molecular analysis of functionally characterized synapses reveals variability in the content of one of the key vesicle priming factors – Munc13-1 – in AZs that possess the same N. Replica immunolabeling also shows a threefold variability in the total Munc13-1 content of AZs of identical size and a fourfold variability in the size and density of Munc13-1 clusters within the AZs. Our results provide evidence for quantitative molecular heterogeneity of RSs and support a model in which the AZ is built up from variable numbers of molecularly heterogeneous, but independent RSs.
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Affiliation(s)
- Maria Rita Karlocai
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Judit Heredi
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Tünde Benedek
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Noemi Holderith
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Andrea Lorincz
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
| | - Zoltan Nusser
- Laboratory of Cellular Neurophysiology, Institute of Experimental Medicine, Budapest, Hungary
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59
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Martínez-Torres NI, Vázquez-Hernández N, Martín-Amaya-Barajas FL, Flores-Soto M, González-Burgos I. Ibotenic acid induced lesions impair the modulation of dendritic spine plasticity in the prefrontal cortex and amygdala, a phenomenon that underlies working memory and social behavior. Eur J Pharmacol 2021; 896:173883. [PMID: 33513334 DOI: 10.1016/j.ejphar.2021.173883] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 01/12/2021] [Accepted: 01/14/2021] [Indexed: 01/08/2023]
Abstract
The lesions induced by Ibotenic acid (IA) emulate some of the symptoms associated with schizophrenia, such as impaired working memory that is predominantly organized by the medial prefrontal cortex (mPFC), or difficulties in social interactions that aremainly organized by the amygdala (AMG). The plastic capacity of dendritic spines in neurons of the mPFC and AMG is modulated by molecules that participate in the known deterioration of working memory, although the influence of these on the socialization of schizophrenic patients is unknown. Here, the effect of a neonatal IA induced lesion on social behavior and working memory was evaluated in adult rats, along with the changes in cytoarchitecture of dendritic spines and their protein content, specifically the postsynaptic density protein 95 (PSD-95), Synaptophysin (Syn), AMPA receptors, and brain-derived neurotrophic factor (BDNF). Both working memory and social behavior were impaired, and the density of the spines, as well as their PSD-95, Syn, AMPA receptor and BDNF content was lower in IA lesioned animals. The proportional density of thin, mushroom, stubby and wide spines resulted in plastic changes that suggest the activation of compensatory processes in the face of the adverse effects of the lesion. In addition, the reduction in the levels of the modulating factors also suggests that the signaling pathways in which such factors are implicated would be altered in the brains of patients with schizophrenia. Accordingly, the experimental study of such signaling pathways is likely to aid the development of more effective pharmacological strategies for the treatment of schizophrenia.
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Affiliation(s)
- Néstor I Martínez-Torres
- División de Neurociencias, Centro de Investigación Biomédica de Occidente, Guadalajara, Jal., Mexico; Centro Universitario del Norte, Universidad de Guadalajara, Colotlán, Jal., Mexico
| | - Nallely Vázquez-Hernández
- División de Neurociencias, Centro de Investigación Biomédica de Occidente, Guadalajara, Jal., Mexico
| | | | - Mario Flores-Soto
- División de Neurociencias, Centro de Investigación Biomédica de Occidente, Guadalajara, Jal., Mexico
| | - Ignacio González-Burgos
- División de Neurociencias, Centro de Investigación Biomédica de Occidente, Guadalajara, Jal., Mexico.
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Ramos-Fernández E, Arrázola MS, Oliva CA, Arredondo SB, Varela-Nallar L, Inestrosa NC. Wnt5a promotes hippocampal postsynaptic development and GluN2B-induced expression via the eIF2α HRI kinase. Sci Rep 2021; 11:7395. [PMID: 33795747 PMCID: PMC8016897 DOI: 10.1038/s41598-021-86708-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 03/18/2021] [Indexed: 12/30/2022] Open
Abstract
Wnt signaling plays a key role in neurodevelopment and neuronal maturation. Specifically, Wnt5a stimulates postsynaptic assemblies, increases glutamatergic neurotransmission and, through calcium signaling, generates nitric oxide (NO). Trying to unveil the molecular pathway triggering these postsynaptic effects, we found that Wnt5a treatment induces a time-dependent increases in the length of the postsynaptic density (PSD), elicits novel synaptic contacts and facilitates F-actin flow both in in vitro and ex vivo models. These effects were partially abolished by the inhibition of the Heme-regulated eukaryotic initiation factor 2α (HRI) kinase, a kinase which phosphorylates the initiation translational factor eIF2α. When phosphorylated, eIF2α normally avoids the translation of proteins not needed during stress conditions, in order to avoid unnecessary energetic expenses. However, phosphorylated eIF2α promotes the translation of some proteins with more than one open reading frame in its 5′ untranslated region. One of these proteins targeted by Wnt-HRI-eIF2α mediated translation is the GluN2B subunit of the NMDA receptor. The identified increase in GluN2B expression correlated with increased NMDA receptor function. Considering that NMDA receptors are crucial for excitatory synaptic transmission, the molecular pathway described here contributes to the understanding of the fast and plastic translational mechanisms activated during learning and memory processes.
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Affiliation(s)
- Eva Ramos-Fernández
- Centro de Envejecimiento y Regeneración (CARE UC), CARE UC Biomedical Center, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Alameda 340, 8331150, Santiago, Chile. .,École polytechnique fédérale de Lausanne, Lausanne, Switzerland.
| | - Macarena S Arrázola
- Centro de Envejecimiento y Regeneración (CARE UC), CARE UC Biomedical Center, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Alameda 340, 8331150, Santiago, Chile.,Centro de Biología Integrativa, Universidad Mayor, Santiago, Chile
| | - Carolina A Oliva
- Centro de Envejecimiento y Regeneración (CARE UC), CARE UC Biomedical Center, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Alameda 340, 8331150, Santiago, Chile
| | - Sebastián B Arredondo
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de La Vida, Universidad Andrés Bello, Santiago, Chile
| | - Lorena Varela-Nallar
- Instituto de Ciencias Biomédicas, Facultad de Medicina y Facultad de Ciencias de La Vida, Universidad Andrés Bello, Santiago, Chile
| | - Nibaldo C Inestrosa
- Centro de Envejecimiento y Regeneración (CARE UC), CARE UC Biomedical Center, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Av. Alameda 340, 8331150, Santiago, Chile. .,Centro de Excelencia en Biomedicina de Magallanes (CEBIMA), Universidad de Magallanes, Punta Arenas, Chile.
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PSD-95 in CA1 Area Regulates Spatial Choice Depending on Age. J Neurosci 2021; 41:2329-2343. [PMID: 33472821 DOI: 10.1523/jneurosci.1996-20.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 10/06/2020] [Accepted: 12/21/2020] [Indexed: 11/21/2022] Open
Abstract
Cognitive processes that require spatial information rely on synaptic plasticity in the dorsal CA1 area (dCA1) of the hippocampus. Since the function of the hippocampus is impaired in aged individuals, it remains unknown how aged animals make spatial choices. Here, we used IntelliCage to study behavioral processes that support spatial choices of aged female mice living in a group. As a proxy of training-induced synaptic plasticity, we analyzed the morphology of dendritic spines and the expression of a synaptic scaffold protein, PSD-95. We observed that spatial choice training in young adult mice induced correlated shrinkage of dendritic spines and downregulation of PSD-95 in dCA1. Moreover, long-term depletion of PSD-95 by shRNA in dCA1 limited correct choices to a reward corner, while reward preference was intact. In contrast, old mice used behavioral strategies characterized by an increased tendency for perseverative visits and social interactions. This strategy resulted in a robust preference for the reward corner during the spatial choice task. Moreover, training decreased the correlation between PSD-95 expression and the size of dendritic spines. Furthermore, PSD-95 depletion did not impair place choice or reward preference in old mice. Thus, our data indicate that while young mice require PSD-95-dependent synaptic plasticity in dCA1 to make correct spatial choices, old animals observe cage mates and stick to a preferred corner to seek the reward. This strategy is resistant to the depletion of PSD-95 in the CA1 area. Overall, our study demonstrates that aged mice combine alternative behavioral and molecular strategies to approach and consume rewards in a complex environment.SIGNIFICANCE STATEMENT It remains poorly understood how aging affects behavioral and molecular processes that support cognitive functions. It is, however, essential to understand these processes to develop therapeutic interventions that support successful cognitive aging. Our data indicate that while young mice require PSD-95-dependent synaptic plasticity in dCA1 to make correct spatial choices (i.e., choices that require spatial information), old animals observe cage mates and stick to a preferred corner to seek the reward. This strategy is resistant to the depletion of PSD-95 in the CA1 area. Overall, our study demonstrates that aged mice combine alternative behavioral and molecular strategies to approach and consume rewards in a complex environment. Second, the contribution of PSD-95-dependent synaptic functions in spatial choice changes with age.
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Yusifov R, Tippmann A, Staiger JF, Schlüter OM, Löwel S. Spine dynamics of PSD-95-deficient neurons in the visual cortex link silent synapses to structural cortical plasticity. Proc Natl Acad Sci U S A 2021; 118:e2022701118. [PMID: 33649238 PMCID: PMC7958355 DOI: 10.1073/pnas.2022701118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Critical periods (CPs) are time windows of heightened brain plasticity during which experience refines synaptic connections to achieve mature functionality. At glutamatergic synapses on dendritic spines of principal cortical neurons, the maturation is largely governed by postsynaptic density protein-95 (PSD-95)-dependent synaptic incorporation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors into nascent AMPA-receptor silent synapses. Consequently, in mouse primary visual cortex (V1), impaired silent synapse maturation in PSD-95-deficient neurons prevents the closure of the CP for juvenile ocular dominance plasticity (jODP). A structural hallmark of jODP is increased spine elimination, induced by brief monocular deprivation (MD). However, it is unknown whether impaired silent synapse maturation facilitates spine elimination and also preserves juvenile structural plasticity. Using two-photon microscopy, we assessed spine dynamics in apical dendrites of layer 2/3 pyramidal neurons (PNs) in binocular V1 during ODP in awake adult mice. Under basal conditions, spine formation and elimination ratios were similar between PSD-95 knockout (KO) and wild-type (WT) mice. However, a brief MD affected spine dynamics only in KO mice, where MD doubled spine elimination, primarily affecting newly formed spines, and caused a net reduction in spine density similar to what has been observed during jODP in WT mice. A similar increase in spine elimination after MD occurred if PSD-95 was knocked down in single PNs of layer 2/3. Thus, structural plasticity is dictated cell autonomously by PSD-95 in vivo in awake mice. Loss of PSD-95 preserves hallmark features of spine dynamics in jODP into adulthood, revealing a functional link of PSD-95 for experience-dependent synapse maturation and stabilization during CPs.
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Affiliation(s)
- Rashad Yusifov
- Department of Systems Neuroscience, Johann Friedrich Blumenbach Institut für Zoologie und Anthropologie, Universität Göttingen, D-37075 Göttingen, Germany
- Collaborative Research Center 889, Universität Göttingen, D-37075 Göttingen, Germany
- Campus Institute for Dynamics of Biological Networks, Universität Göttingen, D-37075 Göttingen, Germany
| | - Anja Tippmann
- Department of Systems Neuroscience, Johann Friedrich Blumenbach Institut für Zoologie und Anthropologie, Universität Göttingen, D-37075 Göttingen, Germany
- Campus Institute for Dynamics of Biological Networks, Universität Göttingen, D-37075 Göttingen, Germany
| | - Jochen F Staiger
- Collaborative Research Center 889, Universität Göttingen, D-37075 Göttingen, Germany
- Institute for Neuroanatomy, University Medical Center, Universität Göttingen, D-37075 Göttingen, Germany
| | - Oliver M Schlüter
- Collaborative Research Center 889, Universität Göttingen, D-37075 Göttingen, Germany
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA 15260
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Universität Göttingen, D-37075 Göttingen, Germany
| | - Siegrid Löwel
- Department of Systems Neuroscience, Johann Friedrich Blumenbach Institut für Zoologie und Anthropologie, Universität Göttingen, D-37075 Göttingen, Germany;
- Collaborative Research Center 889, Universität Göttingen, D-37075 Göttingen, Germany
- Campus Institute for Dynamics of Biological Networks, Universität Göttingen, D-37075 Göttingen, Germany
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63
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Martínez-Torres N, González-Tapia D, Flores-Soto M, Vázquez-Hernández N, Salgado-Ceballos H, González-Burgos I. Spinogenesis in spinal cord motor neurons following pharmacological lesions to the rat motor cortex. NEUROLOGÍA (ENGLISH EDITION) 2021. [DOI: 10.1016/j.nrleng.2017.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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64
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Irollo E, Luchetta J, Ho C, Nash B, Meucci O. Mechanisms of neuronal dysfunction in HIV-associated neurocognitive disorders. Cell Mol Life Sci 2021; 78:4283-4303. [PMID: 33585975 PMCID: PMC8164580 DOI: 10.1007/s00018-021-03785-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 01/14/2021] [Accepted: 01/29/2021] [Indexed: 12/13/2022]
Abstract
HIV-associated neurocognitive disorder (HAND) is characterized by cognitive and behavioral deficits in people living with HIV. HAND is still common in patients that take antiretroviral therapies, although they tend to present with less severe symptoms. The continued prevalence of HAND in treated patients is a major therapeutic challenge, as even minor cognitive impairment decreases patient’s quality of life. Therefore, modern HAND research aims to broaden our understanding of the mechanisms that drive cognitive impairment in people with HIV and identify promising molecular pathways and targets that could be exploited therapeutically. Recent studies suggest that HAND in treated patients is at least partially induced by subtle synaptodendritic damage and disruption of neuronal networks in brain areas that mediate learning, memory, and executive functions. Although the causes of subtle neuronal dysfunction are varied, reversing synaptodendritic damage in animal models restores cognitive function and thus highlights a promising therapeutic approach. In this review, we examine evidence of synaptodendritic damage and disrupted neuronal connectivity in HAND from clinical neuroimaging and neuropathology studies and discuss studies in HAND models that define structural and functional impairment of neurotransmission. Then, we report molecular pathways, mechanisms, and comorbidities involved in this neuronal dysfunction, discuss new approaches to reverse neuronal damage, and highlight current gaps in knowledge. Continued research on the manifestation and mechanisms of synaptic injury and network dysfunction in HAND patients and experimental models will be critical if we are to develop safe and effective therapies that reverse subtle neuropathology and cognitive impairment.
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Affiliation(s)
- Elena Irollo
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Jared Luchetta
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Chunta Ho
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Bradley Nash
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA
| | - Olimpia Meucci
- Department of Pharmacology and Physiology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA. .,Department of Microbiology and Immunology, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA. .,Center for Neuroimmunology and CNS Therapeutics, Institute for Molecular Medicine and Infectious Disease, Drexel University College of Medicine, 245 N. 15th Street, Philadelphia, PA, 19102, USA.
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65
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DeMarco E, Tesmer AL, Hech B, Kawakami K, Robles E. Pyramidal Neurons of the Zebrafish Tectum Receive Highly Convergent Input From Torus Longitudinalis. Front Neuroanat 2021; 15:636683. [PMID: 33613200 PMCID: PMC7886788 DOI: 10.3389/fnana.2021.636683] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2020] [Accepted: 01/06/2021] [Indexed: 12/02/2022] Open
Abstract
The torus longitudinalis (TL) is a midbrain structure unique to ray finned fish. Although previously implicated in orienting behaviors elicited by changes in ambient lighting, the role of TL in visual processing is not well-understood. TL is reciprocally connected to tectum and is the only known source of synaptic input to the stratum marginalis (SM) layer of tectal neuropil. Conversely, tectal pyramidal neurons (PyrNs) are the only identified tectal neuron population that forms a dendrite in SM. In this study we describe a zebrafish gal4 transgenic that labels TL neurons that project to SM. We demonstrate that the axonal TL projection to SM in zebrafish is glutamatergic. Consistent with these axons synapsing directly onto PyrNs, SM-targeted dendrites of PyrNs contain punctate enrichments of the glutamatergic post-synaptic marker protein PSD95. Sparse genetic labeling of individual TL axons and PyrN dendrites enabled quantitative morphometric analysis that revealed (1) large, sparsely branched TL axons in SM and (2) small, densely innervated PyrN dendrites in SM. Together this unique combination of morphologies support a wiring diagram in which TL inputs to PyrNs exhibit a high degree of convergence. We propose that this convergence functions to generate large, compound visual receptive fields in PyrNs. This quantitative anatomical data will instruct future functional studies aimed at identifying the precise contribution of TL-PyrN circuitry to visual behavior.
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Affiliation(s)
- Elisabeth DeMarco
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
| | - Alexander L Tesmer
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
| | - Bruna Hech
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
| | - Koichi Kawakami
- Department of Gene Function, National Institute of Genetics, Mishima, Japan
| | - Estuardo Robles
- Department of Biological Sciences and Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
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66
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The aging mouse brain: cognition, connectivity and calcium. Cell Calcium 2021; 94:102358. [PMID: 33517250 DOI: 10.1016/j.ceca.2021.102358] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 02/08/2023]
Abstract
Aging is a complex process that differentially impacts multiple cognitive, sensory, neuronal and molecular processes. Technological innovations now allow for parallel investigation of neuronal circuit function, structure and molecular composition in the brain of awake behaving adult mice. Thus, mice have become a critical tool to better understand how aging impacts the brain. However, a more granular systems-based approach, which considers the impact of age on key features relating to neural processing, is required. Here, we review evidence probing the impact of age on the mouse brain. We focus on a range of processes relating to neuronal function, including cognitive abilities, sensory systems, synaptic plasticity and calcium regulation. Across many systems, we find evidence for prominent age-related dysregulation even before 12 months of age, suggesting that emerging age-related alterations can manifest by late adulthood. However, we also find reports suggesting that some processes are remarkably resilient to aging. The evidence suggests that aging does not drive a parallel, linear dysregulation of all systems, but instead impacts some processes earlier, and more severely, than others. We propose that capturing the more fine-scale emerging features of age-related vulnerability and resilience may provide better opportunities for the rejuvenation of the aged brain.
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67
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Graves AR, Roth RH, Tan HL, Zhu Q, Bygrave AM, Lopez-Ortega E, Hong I, Spiegel AC, Johnson RC, Vogelstein JT, Tward DJ, Miller MI, Huganir RL. Visualizing synaptic plasticity in vivo by large-scale imaging of endogenous AMPA receptors. eLife 2021; 10:66809. [PMID: 34658338 PMCID: PMC8616579 DOI: 10.7554/elife.66809] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 10/16/2021] [Indexed: 02/06/2023] Open
Abstract
Elucidating how synaptic molecules such as AMPA receptors mediate neuronal communication and tracking their dynamic expression during behavior is crucial to understand cognition and disease, but current technological barriers preclude large-scale exploration of molecular dynamics in vivo. We have developed a suite of innovative methodologies that break through these barriers: a new knockin mouse line with fluorescently tagged endogenous AMPA receptors, two-photon imaging of hundreds of thousands of labeled synapses in behaving mice, and computer vision-based automatic synapse detection. Using these tools, we can longitudinally track how the strength of populations of synapses changes during behavior. We used this approach to generate an unprecedentedly detailed spatiotemporal map of synapses undergoing changes in strength following sensory experience. More generally, these tools can be used as an optical probe capable of measuring functional synapse strength across entire brain areas during any behavioral paradigm, describing complex system-wide changes with molecular precision.
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Affiliation(s)
- Austin R Graves
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
| | - Richard H Roth
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Han L Tan
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Qianwen Zhu
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Alexei M Bygrave
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Elena Lopez-Ortega
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ingie Hong
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Alina C Spiegel
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
| | - Richard C Johnson
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Joshua T Vogelstein
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Daniel J Tward
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Michael I Miller
- Kavli Neuroscience Discovery InstituteBaltimoreUnited States,Center for Imaging Science, Johns Hopkins University School of EngineeringBaltimoreUnited States,Department of Biomedical Engineering, Johns Hopkins UniversityBaltimoreUnited States
| | - Richard L Huganir
- Department of Neuroscience, Johns Hopkins University School of MedicineBaltimoreUnited States,Kavli Neuroscience Discovery InstituteBaltimoreUnited States
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68
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Yap K, Drakew A, Smilovic D, Rietsche M, Paul MH, Vuksic M, Del Turco D, Deller T. The actin-modulating protein synaptopodin mediates long-term survival of dendritic spines. eLife 2020; 9:e62944. [PMID: 33275099 PMCID: PMC7717903 DOI: 10.7554/elife.62944] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 11/14/2020] [Indexed: 12/15/2022] Open
Abstract
Large spines are stable and important for memory trace formation. The majority of large spines also contains synaptopodin (SP), an actin-modulating and plasticity-related protein. Since SP stabilizes F-actin, we speculated that the presence of SP within large spines could explain their long lifetime. Indeed, using 2-photon time-lapse imaging of SP-transgenic granule cells in mouse organotypic tissue cultures we found that spines containing SP survived considerably longer than spines of equal size without SP. Of note, SP-positive (SP+) spines that underwent pruning first lost SP before disappearing. Whereas the survival time courses of SP+ spines followed conditional two-stage decay functions, SP-negative (SP-) spines and all spines of SP-deficient animals showed single-phase exponential decays. This was also the case following afferent denervation. These results implicate SP as a major regulator of long-term spine stability: SP clusters stabilize spines, and the presence of SP indicates spines of high stability.
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Affiliation(s)
- Kenrick Yap
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Alexander Drakew
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Dinko Smilovic
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
- Croatian Institute for Brain Research, School of Medicine, University of ZagrebZagrebCroatia
| | - Michael Rietsche
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Mandy H Paul
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Mario Vuksic
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
- Croatian Institute for Brain Research, School of Medicine, University of ZagrebZagrebCroatia
| | - Domenico Del Turco
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
| | - Thomas Deller
- Institute of Clinical Neuroanatomy, Dr. Senckenberg Anatomy, Neuroscience Center, Goethe University FrankfurtFrankfurtGermany
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69
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Tamada H, Blanc J, Korogod N, Petersen CC, Knott GW. Ultrastructural comparison of dendritic spine morphology preserved with cryo and chemical fixation. eLife 2020; 9:56384. [PMID: 33274717 PMCID: PMC7748412 DOI: 10.7554/elife.56384] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Accepted: 12/04/2020] [Indexed: 12/25/2022] Open
Abstract
Previously, we showed that cryo fixation of adult mouse brain tissue gave a truer representation of brain ultrastructure in comparison with a standard chemical fixation method (Korogod et al., 2015). Extracellular space matched physiological measurements, there were larger numbers of docked vesicles and less glial coverage of synapses and blood capillaries. Here, using the same preservation approaches, we compared the morphology of dendritic spines. We show that the length of the spine and the volume of its head is unchanged; however, the spine neck width is thinner by more than 30% after cryo fixation. In addition, the weak correlation between spine neck width and head volume seen after chemical fixation was not present in cryo-fixed spines. Our data suggest that spine neck geometry is independent of the spine head volume, with cryo fixation showing enhanced spine head compartmentalization and a higher predicted electrical resistance between spine head and parent dendrite.
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Affiliation(s)
- Hiromi Tamada
- Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,Functional Anatomy and Neuroscience, Graduate School of Medicine, Nagoya University, Nagoya, Japan.,Japan Society of the Promotion of Sciences (JSPS), Tokyo, Japan
| | - Jerome Blanc
- Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Natalya Korogod
- Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland.,School of Health Sciences (HESAV), University of Applied Sciences and Arts Western Switzerland (HES-SO), Lausanne, Switzerland
| | - Carl Ch Petersen
- Laboratory of Sensory Processing, Brain Mind Institute, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Graham W Knott
- Biological Electron Microscopy Facility, Faculty of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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70
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Snow WM, Cadonic C, Cortes-Perez C, Adlimoghaddam A, Roy Chowdhury SK, Thomson E, Anozie A, Bernstein MJ, Gough K, Fernyhough P, Suh M, Albensi BC. Sex-Specific Effects of Chronic Creatine Supplementation on Hippocampal-Mediated Spatial Cognition in the 3xTg Mouse Model of Alzheimer's Disease. Nutrients 2020; 12:nu12113589. [PMID: 33238473 PMCID: PMC7700653 DOI: 10.3390/nu12113589] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/18/2020] [Accepted: 11/19/2020] [Indexed: 12/23/2022] Open
Abstract
The creatine (Cr) energy system has been implicated in Alzheimer’s disease (AD), including reductions in brain phosphoCr and Cr kinase, yet no studies have examined the neurobehavioral effects of Cr supplementation in AD, including the 3xTg mouse model. This studied investigated the effects of Cr supplementation on spatial cognition, plasticity- and disease-related protein levels, and mitochondrial function in the 3xTg hippocampus. Here, 3xTg mice were fed a control or Cr-supplemented (3% Cr (w/w)) diet for 8–9 weeks and tested in the Morris water maze. Mitochondrial oxygen consumption (Seahorse) and protein levels (Western blots) were measured in the hippocampus in subsets of mice. Overall, 3xTg females exhibited impaired memory as compared to males. In females, Cr supplementation decreased escape latency and was associated with increased spatial search strategy use. In males, Cr supplementation decreased the use of spatial search strategies. Pilot data indicated mitochondrial enhancements with Cr supplementation in both sexes. In females, Cr supplementation increased CREB phosphorylation and levels of IκB (NF-κB suppressor), CaMKII, PSD-95, and high-molecular-weight amyloid β (Aβ) species, whereas Aβ trimers were reduced. These data suggest a beneficial preventative effect of Cr supplementation in females and warrant caution against Cr supplementation in males in the AD-like brain.
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Affiliation(s)
- Wanda M. Snow
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
- Centre for the Advancement of Teaching and Learning, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Correspondence: or (W.M.S); (B.C.A.); Tel.: +1-204-235-3942 (B.C.A.)
| | - Chris Cadonic
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
| | - Claudia Cortes-Perez
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
| | - Aida Adlimoghaddam
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
| | - Subir K. Roy Chowdhury
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
- Research Institute in Oncology, CancerCare Manitoba, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Ella Thomson
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
| | - Adama Anozie
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
| | - Michael J. Bernstein
- Department of Psychological and Social Sciences, Pennsylvania State University Abington, Abington, PA 19001, USA;
| | - Kathleen Gough
- Department of Chemistry, University of Manitoba, Winnipeg, MB R3T 2N2, Canada;
| | - Paul Fernyhough
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Miyoung Suh
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
- Department of Human Nutritional Sciences, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
| | - Benedict C. Albensi
- Division of Neurodegenerative Disorders, St Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB R2H2A6, Canada; (C.C.); (C.C.-P.); (A.A.); (S.K.R.C.); (E.T.); (A.A.); (P.F.); (M.S.)
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB R3T 2N2, Canada
- Correspondence: or (W.M.S); (B.C.A.); Tel.: +1-204-235-3942 (B.C.A.)
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71
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Facchin L, Schöne C, Mensen A, Bandarabadi M, Pilotto F, Saxena S, Libourel PA, Bassetti CLA, Adamantidis AR. Slow Waves Promote Sleep-Dependent Plasticity and Functional Recovery after Stroke. J Neurosci 2020; 40:8637-8651. [PMID: 33087472 PMCID: PMC7643301 DOI: 10.1523/jneurosci.0373-20.2020] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Revised: 09/15/2020] [Accepted: 09/24/2020] [Indexed: 01/13/2023] Open
Abstract
Functional recovery after stroke is associated with a remapping of neural circuits. This reorganization is often associated with low-frequency, high-amplitude oscillations in the peri-infarct zone in both rodents and humans. These oscillations are reminiscent of sleep slow waves (SW) and suggestive of a role for sleep in brain plasticity that occur during stroke recovery; however, direct evidence is missing. Using a stroke model in male mice, we showed that stroke was followed by a transient increase in NREM sleep accompanied by reduced amplitude and slope of ipsilateral NREM sleep SW. We next used 5 ms optical activation of Channelrhodopsin 2-expressing pyramidal neurons, or 200 ms silencing of Archeorhodopsin T-expressing pyramidal neurons, to generate local cortical UP, or DOWN, states, respectively, both sharing similarities with spontaneous NREM SW in freely moving mice. Importantly, we found that single optogenetically evoked SW (SWopto) in the peri-infarct zone, randomly distributed during sleep, significantly improved fine motor movements of the limb corresponding to the sensorimotor stroke lesion site compared with spontaneous recovery and control conditions, while motor strength remained unchanged. In contrast, SWopto during wakefulness had no effect. Furthermore, chronic SWopto during sleep were associated with local axonal sprouting as revealed by the increase of anatomic presynaptic and postsynaptic markers in the peri-infarct zone and corresponding contralesional areas to cortical circuit reorganization during stroke recovery. These results support a role for sleep SW in cortical circuit plasticity and sensorimotor recovery after stroke and provide a clinically relevant framework for rehabilitation strategies using neuromodulation during sleep.SIGNIFICANCE STATEMENT Brain stroke is one of the leading causes of death and major disabilities in the elderly worldwide. A better understanding of the pathophysiological mechanisms underlying spontaneous brain plasticity after stroke, together with an optimization of rehabilitative strategies, are essential to improve stroke treatments. Here, we investigate the role of optogenetically induced sleep slow waves in an animal model of ischemic stroke and identify sleep as a window for poststroke intervention that promotes neuroplasticity and facilitates sensorimotor recovery.
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Affiliation(s)
- Laura Facchin
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
| | - Cornelia Schöne
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
| | - Armand Mensen
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, 3010, Switzerland
| | - Mojtaba Bandarabadi
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
| | - Federica Pilotto
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, 3010, Switzerland
| | - Smita Saxena
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
- Department for BioMedical Research, University of Bern, Bern, 3010, Switzerland
| | - Paul Antoine Libourel
- Centre de Recherche en Neurosciences de Lyon, University of Lyon, Bron, 69500, France
| | - Claudio L A Bassetti
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, 3010, Switzerland
| | - Antoine R Adamantidis
- Centre for Experimental Neurology, Department of Neurology, Inselspital University Hospital, University of Bern, 3010, Bern, Switzerland
- Department of Neurology, Inselspital University Hospital, University of Bern, Bern, 3010, Switzerland
- Department for BioMedical Research, University of Bern, Bern, 3010, Switzerland
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72
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Zagrebelsky M, Tacke C, Korte M. BDNF signaling during the lifetime of dendritic spines. Cell Tissue Res 2020; 382:185-199. [PMID: 32537724 PMCID: PMC7529616 DOI: 10.1007/s00441-020-03226-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 04/27/2020] [Indexed: 12/13/2022]
Abstract
Dendritic spines are tiny membrane specialization forming the postsynaptic part of most excitatory synapses. They have been suggested to play a crucial role in regulating synaptic transmission during development and in adult learning processes. Changes in their number, size, and shape are correlated with processes of structural synaptic plasticity and learning and memory and also with neurodegenerative diseases, when spines are lost. Thus, their alterations can correlate with neuronal homeostasis, but also with dysfunction in several neurological disorders characterized by cognitive impairment. Therefore, it is important to understand how different stages in the life of a dendritic spine, including formation, maturation, and plasticity, are strictly regulated. In this context, brain-derived neurotrophic factor (BDNF), belonging to the NGF-neurotrophin family, is among the most intensively investigated molecule. This review would like to report the current knowledge regarding the role of BDNF in regulating dendritic spine number, structure, and plasticity concentrating especially on its signaling via its two often functionally antagonistic receptors, TrkB and p75NTR. In addition, we point out a series of open points in which, while the role of BDNF signaling is extremely likely conclusive, evidence is still missing.
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Affiliation(s)
- Marta Zagrebelsky
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, Spielmannstr 7, 38106, Braunschweig, Germany.
- Helmholtz Centre for Infection Research, AG NIND, Inhoffenstr. 7, D-38124, Braunschweig, Germany.
| | - Charlotte Tacke
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, Spielmannstr 7, 38106, Braunschweig, Germany
| | - Martin Korte
- Division of Cellular Neurobiology, Zoological Institute, TU Braunschweig, Spielmannstr 7, 38106, Braunschweig, Germany.
- Helmholtz Centre for Infection Research, AG NIND, Inhoffenstr. 7, D-38124, Braunschweig, Germany.
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73
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Huebschman JL, Corona KS, Guo Y, Smith LN. The Fragile X Mental Retardation Protein Regulates Striatal Medium Spiny Neuron Synapse Density and Dendritic Spine Morphology. Front Mol Neurosci 2020; 13:161. [PMID: 33013316 PMCID: PMC7511717 DOI: 10.3389/fnmol.2020.00161] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 08/05/2020] [Indexed: 01/23/2023] Open
Abstract
The fragile X mental retardation protein (FMRP), an RNA-binding protein that mediates the transport, stability, and translation of hundreds of brain RNAs, is critically involved in regulating synaptic function. Loss of FMRP, as in fragile X syndrome (FXS), is a leading monogenic cause of autism and results in altered structural and functional synaptic plasticity, widely described in the hippocampus and cortex. Though FXS is associated with hyperactivity, impaired social interaction, and the development of repetitive or stereotyped behaviors, all of which are influenced by striatal activity, few studies have investigated the function of FMRP here. Utilizing a cortical-striatal co-culture model, we find that striatal medium spiny neurons (MSNs) lacking FMRP fail to make normal increases in PSD95 expression over a short time period and have significant deficits in dendritic spine density and colocalized synaptic puncta at the later measured time point compared to wildtype (WT) MSNs. Acute expression of wtFMRP plasmid in Fmr1 KO co-cultures results in contrasting outcomes for these measures on MSNs at the more mature time point, reducing spine density across multiple spine types but making no significant changes in colocalized puncta. FMRP’s KH2 and RGG RNA-binding domains are required for normal elimination of PSD95, and interruption of these domains slightly favors elimination of immature spine types. Further, KH2 is required for normal levels of colocalized puncta. Our data are largely consistent with a basal role for FMRP and its RNA-binding domains in striatal synapse stabilization on developing MSNs, and in light of previous findings, suggest distinct regional and/or cell type-specific roles for FMRP in regulating synapse structure.
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Affiliation(s)
- Jessica L Huebschman
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, Bryan, TX, United States.,Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
| | - Kitzia S Corona
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Yuhong Guo
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, Bryan, TX, United States
| | - Laura N Smith
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center, Bryan, TX, United States.,Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX, United States
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74
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CPG15/Neuritin Mimics Experience in Selecting Excitatory Synapses for Stabilization by Facilitating PSD95 Recruitment. Cell Rep 2020; 28:1584-1595.e5. [PMID: 31390571 PMCID: PMC6740334 DOI: 10.1016/j.celrep.2019.07.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 06/11/2019] [Accepted: 07/02/2019] [Indexed: 11/24/2022] Open
Abstract
A key feature of brain plasticity is the experience-dependent selection of optimal connections· implemented by a set of activity-regulated genes that dynamically adjust synapse strength and number. The activity-regulated gene cpg15/neuritin has been previously implicated in stabilization and maturation of excitatory synapses. Here· we combine two-photon microscopy with genetic and sensory manipulations to dissect excitatory synapse formation in vivo and examine the role of activity and CPG15 in dendritic spine formation, PSD95 recruitment, and synapse stabilization. We find that neither visual experience nor CPG15 is required for spine formation. However, PSD95 recruitment to nascent spines and their subsequent stabilization requires both. Further, cell-autonomous CPG15 expression is sufficient to replace experience in facilitating PSD95 recruitment and spine stabilization. CPG15 directly interacts with α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors on immature dendritic spines, suggesting a signaling mode for this small extracellular molecule acting as an experience-dependent “selector” for spine stabilization and synapse maturation. Experience plays a key role in formation and continuous optimization of brain circuits. Subramanian et al. show that the molecule CPG15/neuritin can replace experience in selecting which nascent contacts between neurons are retained, facilitating the recruitment of proteins that promote synapse maturation and stabilization.
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75
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Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020. [DOI: 10.3389/fnsyn.2020.00036
expr 823669561 + 872784217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023] Open
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76
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Runge K, Cardoso C, de Chevigny A. Dendritic Spine Plasticity: Function and Mechanisms. Front Synaptic Neurosci 2020; 12:36. [PMID: 32982715 PMCID: PMC7484486 DOI: 10.3389/fnsyn.2020.00036] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 07/28/2020] [Indexed: 12/12/2022] Open
Abstract
Dendritic spines are small protrusions studding neuronal dendrites, first described in 1888 by Ramón y Cajal using his famous Golgi stainings. Around 50 years later the advance of electron microscopy (EM) confirmed Cajal's intuition that spines constitute the postsynaptic site of most excitatory synapses in the mammalian brain. The finding that spine density decreases between young and adult ages in fixed tissues suggested that spines are dynamic. It is only a decade ago that two-photon microscopy (TPM) has unambiguously proven the dynamic nature of spines, through the repeated imaging of single spines in live animals. Spine dynamics comprise formation, disappearance, and stabilization of spines and are modulated by neuronal activity and developmental age. Here, we review several emerging concepts in the field that start to answer the following key questions: What are the external signals triggering spine dynamics and the molecular mechanisms involved? What is, in return, the role of spine dynamics in circuit-rewiring, learning, and neuropsychiatric disorders?
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Affiliation(s)
- Karen Runge
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Carlos Cardoso
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
| | - Antoine de Chevigny
- Institut de Neurobiologie de la Méditerranée (INMED) INSERM U1249, Aix-Marseille University, Marseille, France
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77
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Cangalaya C, Stoyanov S, Fischer KD, Dityatev A. Light-induced engagement of microglia to focally remodel synapses in the adult brain. eLife 2020; 9:e58435. [PMID: 32808923 PMCID: PMC7470825 DOI: 10.7554/elife.58435] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 08/18/2020] [Indexed: 12/18/2022] Open
Abstract
Microglia continuously monitor synapses, but active synaptic remodeling by microglia in mature healthy brains is rarely directly observed. We performed targeted photoablation of single synapses in mature transgenic mice expressing fluorescent labels in neurons and microglia. The photodamage focally increased the duration of microglia-neuron contacts, and dramatically exacerbated both the turnover of dendritic spines and presynaptic boutons as well as the generation of new filopodia originating from spine heads or boutons. The results of microglia depletion confirmed that elevated spine turnover and the generation of presynaptic filopodia are microglia-dependent processes.
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Affiliation(s)
- Carla Cangalaya
- ESF International Graduate School on Analysis, Imaging and Modelling of Neuronal and Inflammatory ProcessesMagdeburgGermany
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Stoyan Stoyanov
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
| | - Klaus-Dieter Fischer
- Institut für Biochemie und Zellbiologie, Otto-von-Guericke-University, Medical FacultyMagdeburgGermany
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE)MagdeburgGermany
- Medical Faculty, Otto-von-Guericke UniversityMagdeburgGermany
- Center for Behavioral Brain Sciences (CBBS)MagdeburgGermany
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78
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Bensussen S, Shankar S, Ching KH, Zemel D, Ta TL, Mount RA, Shroff SN, Gritton HJ, Fabris P, Vanbenschoten H, Beck C, Man HY, Han X. A Viral Toolbox of Genetically Encoded Fluorescent Synaptic Tags. iScience 2020; 23:101330. [PMID: 32674057 PMCID: PMC7363701 DOI: 10.1016/j.isci.2020.101330] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 04/18/2020] [Accepted: 06/26/2020] [Indexed: 01/16/2023] Open
Abstract
Fibronectin intrabodies generated with mRNA display (FingRs) are a recently developed tool for labeling excitatory or inhibitory synapses, with the benefit of not altering endogenous synaptic protein expression levels or synaptic transmission. Here, we generated a viral vector FingR toolbox that allows for multi-color, neuron-type-specific labeling of excitatory or inhibitory synapses in multiple brain regions. We screened various fluorophores, FingR fusion configurations, and transcriptional control regulations in adeno-associated virus (AAV) and retrovirus vector designs. We report the development of a red FingR variant and demonstrated dual labeling of excitatory and inhibitory synapses in the same cells. Furthermore, we developed cre-inducible FingR AAV variants and demonstrated their utility, finding that the density of inhibitory synapses in aspiny striatal cholinergic interneurons remained unchanged in response to dopamine depletion. Finally, we generated FingR retroviral vectors, which enabled us to track the development of excitatory and inhibitory synapses in hippocampal adult-born granule cells.
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Affiliation(s)
- Seth Bensussen
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sneha Shankar
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Kimberley H Ching
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Dana Zemel
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Tina L Ta
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Rebecca A Mount
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Sanaya N Shroff
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Howard J Gritton
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Pierre Fabris
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | | | - Connor Beck
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA 02215, USA
| | - Xue Han
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA.
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79
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Xu W, Löwel S, Schlüter OM. Silent Synapse-Based Mechanisms of Critical Period Plasticity. Front Cell Neurosci 2020; 14:213. [PMID: 32765222 PMCID: PMC7380267 DOI: 10.3389/fncel.2020.00213] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 06/17/2020] [Indexed: 01/08/2023] Open
Abstract
Critical periods are postnatal, restricted time windows of heightened plasticity in cortical neural networks, during which experience refines principal neuron wiring configurations. Here, we propose a model with two distinct types of synapses, innate synapses that establish rudimentary networks with innate function, and gestalt synapses that govern the experience-dependent refinement process. Nascent gestalt synapses are constantly formed as AMPA receptor-silent synapses which are the substrates for critical period plasticity. Experience drives the unsilencing and stabilization of gestalt synapses, as well as synapse pruning. This maturation process changes synapse patterning and consequently the functional architecture of cortical excitatory networks. Ocular dominance plasticity (ODP) in the primary visual cortex (V1) is an established experimental model for cortical plasticity. While converging evidence indicates that the start of the critical period for ODP is marked by the maturation of local inhibitory circuits, recent results support our model that critical periods end through the progressive maturation of gestalt synapses. The cooperative yet opposing function of two postsynaptic signaling scaffolds of excitatory synapses, PSD-93 and PSD-95, governs the maturation of gestalt synapses. Without those proteins, networks do not progress far beyond their innate functionality, resulting in rather impaired perception. While cortical networks remain malleable throughout life, the cellular mechanisms and the scope of critical period and adult plasticity differ. Critical period ODP is initiated with the depression of deprived eye responses in V1, whereas adult ODP is characterized by an initial increase in non-deprived eye responses. Our model proposes the gestalt synapse-based mechanism for critical period ODP, and also predicts a different mechanism for adult ODP based on the sparsity of nascent gestalt synapses at that age. Under our model, early life experience shapes the boundaries (the gestalt) for network function, both for its optimal performance as well as for its pathological state. Thus, reintroducing nascent gestalt synapses as plasticity substrates into adults may improve the network gestalt to facilitate functional recovery.
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Affiliation(s)
- Weifeng Xu
- Department of Neuroscience, Brown University, Providence, RI, United States
- Carney Institute for Brain Science, Brown University, Providence, RI, United States
| | - Siegrid Löwel
- Department of Systems Neuroscience, Johann-Friedrich-Blumenbach Institute for Zoology & Anthropology, University of Göttingen, Göttingen, Germany
- Campus Institute for Dynamics of Biological Networks, University of Göttingen, Göttingen, Germany
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
| | - Oliver M. Schlüter
- Collaborative Research Center 889, University of Göttingen, Göttingen, Germany
- Department of Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States
- Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Göttingen, Germany
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80
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Viale B, Song L, Petrenko V, Wenger Combremont AL, Contestabile A, Bocchi R, Salmon P, Carleton A, An L, Vutskits L, Kiss JZ. Transient Deregulation of Canonical Wnt Signaling in Developing Pyramidal Neurons Leads to Dendritic Defects and Impaired Behavior. Cell Rep 2020; 27:1487-1502.e6. [PMID: 31042475 DOI: 10.1016/j.celrep.2019.04.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 02/28/2019] [Accepted: 04/03/2019] [Indexed: 12/30/2022] Open
Abstract
During development, the precise implementation of molecular programs is a key determinant of proper dendritic development. Here, we demonstrate that canonical Wnt signaling is active in dendritic bundle-forming layer II pyramidal neurons of the rat retrosplenial cortex during dendritic branching and spine formation. Transient downregulation of canonical Wnt transcriptional activity during the early postnatal period irreversibly reduces dendritic arbor architecture, leading to long-lasting deficits in spatial exploration and/or navigation and spatial memory in the adult. During the late phase of dendritogenesis, canonical Wnt-dependent transcription regulates spine formation and maturation. We identify neurotrophin-3 as canonical Wnt target gene in regulating dendritogenesis. Our findings demonstrate how temporary imbalance in canonical Wnt signaling during specific time windows can result in irreversible dendritic defects, leading to abnormal behavior in the adult.
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Affiliation(s)
- Beatrice Viale
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | - Lin Song
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland; School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Volodymyr Petrenko
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | | | - Alessandro Contestabile
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | - Riccardo Bocchi
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | - Patrick Salmon
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | - Alan Carleton
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland
| | - Lijia An
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, Liaoning 116024, China
| | - Laszlo Vutskits
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland; Department of Anesthesiology, Pharmacology and Intensive Care, University Hospitals of Geneva, 1211 Geneva 4, Switzerland
| | - Jozsef Zoltan Kiss
- Department of Basic Neurosciences, University of Geneva Medical School, 1211 Geneva 4, Switzerland.
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81
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Yang X. Characterizing spine issues: If offers novel therapeutics to Angelman syndrome. Dev Neurobiol 2020; 80:200-209. [PMID: 32378784 DOI: 10.1002/dneu.22757] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Accepted: 05/01/2020] [Indexed: 12/28/2022]
Abstract
Angelman syndrome (AS) is a rare neurodevelopmental disorder characterized by severe mental retardation, microcephaly, speech impairment, frequent epilepsy, EEG abnormalities, ataxic movements, tongue protrusion, bursts of laughter, sleep abruptions, and hyperactivity. AS results from loss of function of the imprinted UBE3A (ubiquitin-protein ligase E3A) gene on chromosome 15q11-q13, including a mutation on the maternal allele of Ube3a, a large deletion of the maternally inherited chromosomal region 15q11-13, paternal uniparental disomy of chromosome 15q11-13, or an imprinting defect. The Ube3a maternal deleted mouse model recaptured the major phenotypes of AS patients include seizure, learning and memory impairments, sleep disturbance, and motor problems. Owing to the activity-dependent structural and functional plasticity, dendritic spines are believed as the basic subcellular compartment for learning and memory and the sites where LTP and LTD are induced. Defects of spine formation and dynamics are common among several neurodevelopmental disorders and neuropsychiatric disorders including AS and reflect the underlying synaptopathology, which drives clinically relevant behavioral deficits. This review will summarize the impaired spine density, morphology, and synaptic plasticity in AS and propose that future explorations on spine dynamics and synaptic plasticity may help develop novel interventions and therapy for neurodevelopmental disorders like AS.
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Affiliation(s)
- Xin Yang
- Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
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82
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Omelchenko A, Menon H, Donofrio SG, Kumar G, Chapman HM, Roshal J, Martinez-Montes ER, Wang TL, Spaller MR, Firestein BL. Interaction Between CRIPT and PSD-95 Is Required for Proper Dendritic Arborization in Hippocampal Neurons. Mol Neurobiol 2020; 57:2479-2493. [PMID: 32157575 PMCID: PMC7176523 DOI: 10.1007/s12035-020-01895-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 02/24/2020] [Indexed: 01/10/2023]
Abstract
CRIPT, the cysteine-rich PDZ-binding protein, binds to the third PDZ domain of PSD-95 (postsynaptic density protein 95) family proteins and directly binds microtubules, linking PSD-95 family proteins to the neuronal cytoskeleton. Here, we show that overexpression of a full-length CRIPT leads to a modest decrease, and knockdown of CRIPT leads to an increase in dendritic branching in cultured rat hippocampal neurons. Overexpression of truncated CRIPT lacking the PDZ domain-binding motif, which does not bind to PSD-95, significantly decreases dendritic arborization. Conversely, overexpression of a full-length CRIPT significantly increases the number of immature and mature dendritic spines, and this effect is not observed when CRIPT∆PDZ is overexpressed. Competitive inhibition of CRIPT binding to the third PDZ domain of PSD-95 with PDZ3-binding peptides resulted in differential effects on dendritic arborization based on the origin of respective peptide sequence. These results highlight multifunctional roles of CRIPT during development and underscore the significance of the interaction between CRIPT and the third PDZ domain of PSD-95.
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Affiliation(s)
- Anton Omelchenko
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
- Neuroscience Graduate Program, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Harita Menon
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Sarah G Donofrio
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Gaurav Kumar
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Heidi M Chapman
- Geisel School of Medicine, Department of Medical Education and Norris Cotton Cancer Center, Dartmouth College, Lebanon, NH, 03756, USA
| | - Joshua Roshal
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Eduardo R Martinez-Montes
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA
| | - Tiffany L Wang
- Geisel School of Medicine, Department of Medical Education and Norris Cotton Cancer Center, Dartmouth College, Lebanon, NH, 03756, USA
| | - Mark R Spaller
- Geisel School of Medicine, Department of Medical Education and Norris Cotton Cancer Center, Dartmouth College, Lebanon, NH, 03756, USA
| | - Bonnie L Firestein
- Department of Cell Biology and Neuroscience, Rutgers University, 604 Allison Road, Piscataway, NJ, 08854-8082, USA.
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83
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Letellier M, Lagardère M, Tessier B, Janovjak H, Thoumine O. Optogenetic control of excitatory post-synaptic differentiation through neuroligin-1 tyrosine phosphorylation. eLife 2020; 9:e52027. [PMID: 32324534 PMCID: PMC7180054 DOI: 10.7554/elife.52027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Accepted: 03/25/2020] [Indexed: 12/13/2022] Open
Abstract
Neuroligins (Nlgns) are adhesion proteins mediating trans-synaptic contacts in neurons. However, conflicting results around their role in synaptic differentiation arise from the various techniques used to manipulate Nlgn expression level. Orthogonally to these approaches, we triggered here the phosphorylation of endogenous Nlgn1 in CA1 mouse hippocampal neurons using a photoactivatable tyrosine kinase receptor (optoFGFR1). Light stimulation for 24 hr selectively increased dendritic spine density and AMPA-receptor-mediated EPSCs in wild-type neurons, but not in Nlgn1 knock-out neurons or when endogenous Nlgn1 was replaced by a non-phosphorylatable mutant (Y782F). Moreover, light stimulation of optoFGFR1 partially occluded LTP in a Nlgn1-dependent manner. Combined with computer simulations, our data support a model by which Nlgn1 tyrosine phosphorylation promotes the assembly of an excitatory post-synaptic scaffold that captures surface AMPA receptors. This optogenetic strategy highlights the impact of Nlgn1 intracellular signaling in synaptic differentiation and potentiation, while enabling an acute control of these mechanisms.
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Affiliation(s)
- Mathieu Letellier
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
| | - Matthieu Lagardère
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
| | - Béatrice Tessier
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
| | - Harald Janovjak
- Australian Regenerative Medicine Institute (ARMI), Faculty of Medicine, Nursing and Health Sciences, Monash UniversityClaytonAustralia
- European Molecular Biology Laboratory Australia (EMBL Australia), Monash UniversityClaytonAustralia
| | - Olivier Thoumine
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297BordeauxFrance
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84
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Cheyne JE, Montgomery JM. The cellular and molecular basis of in vivo synaptic plasticity in rodents. Am J Physiol Cell Physiol 2020; 318:C1264-C1283. [PMID: 32320288 DOI: 10.1152/ajpcell.00416.2019] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Plasticity within the neuronal networks of the brain underlies the ability to learn and retain new information. The initial discovery of synaptic plasticity occurred by measuring synaptic strength in vivo, applying external stimulation and observing an increase in synaptic strength termed long-term potentiation (LTP). Many of the molecular pathways involved in LTP and other forms of synaptic plasticity were subsequently uncovered in vitro. Over the last few decades, technological advances in recording and imaging in live animals have seen many of these molecular mechanisms confirmed in vivo, including structural changes both pre- and postsynaptically, changes in synaptic strength, and changes in neuronal excitability. A well-studied aspect of neuronal plasticity is the capacity of the brain to adapt to its environment, gained by comparing the brains of deprived and experienced animals in vivo, and in direct response to sensory stimuli. Multiple in vivo studies have also strongly linked plastic changes to memory by interfering with the expression of plasticity and by manipulating memory engrams. Plasticity in vivo also occurs in the absence of any form of external stimulation, i.e., during spontaneous network activity occurring with brain development. However, there is still much to learn about how plasticity is induced during natural learning and how this is altered in neurological disorders.
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Affiliation(s)
- Juliette E Cheyne
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - Johanna M Montgomery
- Department of Physiology and Centre for Brain Research, University of Auckland, Auckland, New Zealand
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85
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Cirelli C, Tononi G. Effects of sleep and waking on the synaptic ultrastructure. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190235. [PMID: 32248785 PMCID: PMC7209920 DOI: 10.1098/rstb.2019.0235] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
We summarize here several studies performed in our laboratory, mainly using serial block-face scanning electron microscopy (SBEM), to assess how sleep, spontaneous waking and short sleep deprivation affect the size and number of synapses in the cerebral cortex and hippocampus. With SBEM, we reconstructed thousands of cortical and hippocampal excitatory, axospinous synapses and compared the distribution of their size after several hours of sleep relative to several hours of waking. Because stronger synapses are on average also bigger, the goal was to test a prediction of the synaptic homeostasis hypothesis, according to which overall synaptic strength increases during waking, owing to ongoing learning, and needs to be renormalized during sleep, to avoid saturation and to benefit memory consolidation and integration. Consistent with this hypothesis, we found that the size of the axon–spine interface (ASI), a morphological measure of synaptic strength, was on average smaller after sleep, but with interesting differences between primary cortex and the CA1 region of the hippocampus. In two-week-old mouse pups, the decline in ASI size after sleep was larger, and affected more cortical synapses, compared with one-month-old adolescent mice, suggesting that synaptic renormalization during sleep may be especially important during early development. This work is still in progress and other brain areas need to be tested after sleep, acute sleep loss and chronic sleep restriction. Still, the current results show that a few hours of sleep or waking lead to significant changes in synaptic morphology that can be linked to changes in synaptic efficacy. This article is part of the Theo Murphy meeting issue ‘Memory reactivation: replaying events past, present and future’.
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Affiliation(s)
- Chiara Cirelli
- Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA
| | - Giulio Tononi
- Department of Psychiatry, University of Wisconsin-Madison, 6001 Research Park Blvd, Madison, WI 53719, USA
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86
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Activity Dependent and Independent Determinants of Synaptic Size Diversity. J Neurosci 2020; 40:2828-2848. [PMID: 32127494 DOI: 10.1523/jneurosci.2181-19.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/04/2020] [Accepted: 02/13/2020] [Indexed: 11/21/2022] Open
Abstract
The extraordinary diversity of excitatory synapse sizes is commonly attributed to activity-dependent processes that drive synaptic growth and diminution. Recent studies also point to activity-independent size fluctuations, possibly driven by innate synaptic molecule dynamics, as important generators of size diversity. To examine the contributions of activity-dependent and independent processes to excitatory synapse size diversity, we studied glutamatergic synapse size dynamics and diversification in cultured rat cortical neurons (both sexes), silenced from plating. We found that in networks with no history of activity whatsoever, synaptic size diversity was no less extensive than that observed in spontaneously active networks. Synapses in silenced networks were larger, size distributions were broader, yet these were rightward-skewed and similar in shape when scaled by mean synaptic size. Silencing reduced the magnitude of size fluctuations and weakened constraints on size distributions, yet these were sufficient to explain synaptic size diversity in silenced networks. Model-based exploration followed by experimental testing indicated that silencing-associated changes in innate molecular dynamics and fluctuation characteristics might negatively impact synaptic persistence, resulting in reduced synaptic numbers. This, in turn, would increase synaptic molecule availability, promote synaptic enlargement, and ultimately alter fluctuation characteristics. These findings suggest that activity-independent size fluctuations are sufficient to fully diversify glutamatergic synaptic sizes, with activity-dependent processes primarily setting the scale rather than the shape of size distributions. Moreover, they point to reciprocal relationships between synaptic size fluctuations, size distributions, and synaptic numbers mediated by the innate dynamics of synaptic molecules as they move in, out, and between synapses.SIGNIFICANCE STATEMENT Sizes of glutamatergic synapses vary tremendously, even when formed on the same neuron. This diversity is commonly thought to reflect the outcome of activity-dependent forms of synaptic plasticity, yet activity-independent processes might also play some part. Here we show that in neurons with no history of activity whatsoever, synaptic sizes are no less diverse. We show that this diversity is the product of activity-independent size fluctuations, which are sufficient to generate a full repertoire of synaptic sizes at correct proportions. By combining modeling and experimentation we expose reciprocal relationships between size fluctuations, synaptic sizes and synaptic counts, and show how these phenomena might be connected through the dynamics of synaptic molecules as they move in, out, and between synapses.
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87
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Roth RH, Cudmore RH, Tan HL, Hong I, Zhang Y, Huganir RL. Cortical Synaptic AMPA Receptor Plasticity during Motor Learning. Neuron 2019; 105:895-908.e5. [PMID: 31901303 DOI: 10.1016/j.neuron.2019.12.005] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 10/30/2019] [Accepted: 12/04/2019] [Indexed: 02/04/2023]
Abstract
Modulation of synaptic strength through trafficking of AMPA receptors (AMPARs) is a fundamental mechanism underlying synaptic plasticity, learning, and memory. However, the dynamics of AMPAR trafficking in vivo and its correlation with learning have not been resolved. Here, we used in vivo two-photon microscopy to visualize surface AMPARs in mouse cortex during the acquisition of a forelimb reaching task. Daily training leads to an increase in AMPAR levels at a subset of spatially clustered dendritic spines in the motor cortex. Surprisingly, we also observed increases in spine AMPAR levels in the visual cortex. There, synaptic potentiation depends on the availability of visual input during motor training, and optogenetic inhibition of visual cortex activity impairs task performance. These results indicate that motor learning induces widespread cortical synaptic potentiation by increasing the net trafficking of AMPARs into spines, including in non-motor brain regions.
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Affiliation(s)
- Richard H Roth
- Solomon H. Snyder Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Robert H Cudmore
- Department of Physiology and Membrane Biology, University of California School of Medicine, Davis, CA 95616, USA
| | - Han L Tan
- Solomon H. Snyder Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ingie Hong
- Solomon H. Snyder Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yong Zhang
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Key Lab for Neuroscience, Ministry of Education of China and National Health Commission of the P.R. China, IDG/McGovern Institute for Brain Research at PKU, Peking University, Beijing 100191, China
| | - Richard L Huganir
- Solomon H. Snyder Department of Neuroscience and Kavli Neuroscience Discovery Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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88
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Modified Glutamatergic Postsynapse in Neurodegenerative Disorders. Neuroscience 2019; 454:116-139. [PMID: 31887357 DOI: 10.1016/j.neuroscience.2019.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 10/02/2019] [Accepted: 12/02/2019] [Indexed: 01/27/2023]
Abstract
The postsynaptic density (PSD) is a complex subcellular domain important for postsynaptic signaling, function, and plasticity. The PSD is present at excitatory synapses and specialized to allow for precise neuron-to-neuron transmission of information. The PSD is localized immediately underneath the postsynaptic membrane forming a major protein network that regulates postsynaptic signaling and synaptic plasticity. Glutamatergic synaptic dysfunction affecting PSD morphology and signaling events have been described in many neurodegenerative disorders, either sporadic or familial forms. Thus, in this review we describe the main protein players forming the PSD and their activity, as well as relevant modifications in key components of the postsynaptic architecture occurring in Huntington's, Parkinson's and Alzheimer's diseases.
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89
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Evans TA, Bury LA, Huang AY, Sabo SL. Spatio-temporal dynamics of neocortical presynaptic terminal development using multi-photon imaging of the corpus callosum in vivo. Sci Rep 2019; 9:14028. [PMID: 31575884 PMCID: PMC6773694 DOI: 10.1038/s41598-019-50431-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Accepted: 09/12/2019] [Indexed: 11/25/2022] Open
Abstract
Within the developing central nervous system, the dynamics of synapse formation and elimination are insufficiently understood. It is ideal to study these processes in vivo, where neurons form synapses within appropriate behavioral and anatomical contexts. In vivo analysis is particularly important for long-range connections, since their development cannot be adequately studied in vitro. The corpus callosum (CC) represents a clinically-relevant long-range connection since several neurodevelopmental diseases involve CC defects. Here, we present a novel strategy for in vivo longitudinal and rapid time-lapse imaging of CC presynaptic terminal development. In postnatal mice, the time-course of CC presynaptic terminal formation and elimination was highly variable between axons or groups of axons. Young presynaptic terminals were remarkably dynamic - moving, dividing to generate more boutons, and merging to consolidate small terminals into large boutons. As synaptic networks matured, presynaptic mobility decreased. These rapid dynamics may be important for establishing initial synaptic contacts with postsynaptic partners, refining connectivity patterns or modifying synapse strength during development. Ultimately, this in vivo imaging approach will facilitate investigation of synapse development in other long-range connections and neurodevelopmental disease models.
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Affiliation(s)
- Teresa A Evans
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, USA
- Department of Pediatrics, Stanford University, Stanford, USA
| | - Luke A Bury
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, USA
| | - Alex Y Huang
- Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, USA
| | - Shasta L Sabo
- Departments of Pharmacology and Neuroscience, Case Western Reserve University School of Medicine, Cleveland, USA.
- Department of Biology, Central Michigan University, Mount Pleasant, USA.
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90
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Iguchi R, Tanaka S, Okabe S. Neonatal social isolation increases the proportion of the immature spines in the layer 2/3 pyramidal neurons of the somatosensory cortex. Neurosci Res 2019; 154:27-34. [PMID: 31226269 DOI: 10.1016/j.neures.2019.05.004] [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: 01/20/2019] [Revised: 05/17/2019] [Accepted: 05/20/2019] [Indexed: 11/29/2022]
Abstract
Social isolation during the juvenile period is postulated to leave specific sequelae, such as attention deficits and emotion recognition. Miswiring of the cortical neuronal circuit during postnatal development may underlie such behavioral impairments, but the details of the circuit-level impairment associated with social isolation have not yet been clarified. In this study, we evaluated the possibility that environmental factors may induce alternation in spine characteristics and dynamics. We isolated mice from the mother and siblings from postnatal day 7 to 11 for 6 h per day. Both dynamics and structural properties of spines in the layer 2/3 pyramidal neurons of the somatosensory cortex were measured at postnatal 3 weeks by in vivo two-photon microscopy. We found decrease in the ratio of PSD-95-positive dendritic spines in the mice after social isolation. These mice did not show alteration in spine dynamics. Those results suggest that the neonatal social isolation results in less mature spines, with normal rate of their turnover, which is distinct from spine phenotype seen in multiple models of autism spectrum disorders.
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Affiliation(s)
- Risa Iguchi
- Department of Cellular Neurobiology Graduate School of Medicine, University of Tokyo, Tokyo, 113-0033 Japan
| | - Shinji Tanaka
- Department of Cellular Neurobiology Graduate School of Medicine, University of Tokyo, Tokyo, 113-0033 Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology Graduate School of Medicine, University of Tokyo, Tokyo, 113-0033 Japan.
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91
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Pannexin 1 Regulates Network Ensembles and Dendritic Spine Development in Cortical Neurons. eNeuro 2019; 6:ENEURO.0503-18.2019. [PMID: 31118206 PMCID: PMC6557035 DOI: 10.1523/eneuro.0503-18.2019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 01/22/2023] Open
Abstract
Dendritic spines are the postsynaptic targets of excitatory synaptic inputs that undergo extensive proliferation and maturation during the first postnatal month in mice. However, our understanding of the molecular mechanisms that regulate spines during this critical period is limited. Previous work has shown that pannexin 1 (Panx1) regulates neurite growth and synaptic plasticity. We therefore investigated the impact of global Panx1 KO on spontaneous cortical neuron activity using Ca2+ imaging and in silico network analysis. Panx1 KO increased both the number and size of spontaneous co-active cortical neuron network ensembles. To understand the basis for these findings, we investigated Panx1 expression in postnatal synaptosome preparations from early postnatal mouse cortex. Between 2 and 4 postnatal weeks, we observed a precipitous drop in cortical synaptosome protein levels of Panx1, suggesting it regulates synapse proliferation and/or maturation. At the same time points, we observed significant enrichment of the excitatory postsynaptic density proteins PSD-95, GluA1, and GluN2a in cortical synaptosomes from global Panx1 knock-out mice. Ex vivo analysis of pyramidal neuron structure in somatosensory cortex revealed a consistent increase in dendritic spine densities in both male and female Panx1 KO mice. Similar findings were observed in an excitatory neuron-specific Panx1 KO line (Emx1-Cre driven; Panx1 cKOE) and in primary Panx1 KO cortical neurons cultured in vitro. Altogether, our study suggests that Panx1 negatively regulates cortical dendritic spine development.
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92
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Xu N, Li AD, Ji LL, Ye Y, Wang ZY, Tong L. miR-132 regulates the expression of synaptic proteins in APP/PS1 transgenic mice through C1q. Eur J Histochem 2019; 63. [PMID: 31060348 PMCID: PMC6511887 DOI: 10.4081/ejh.2019.3008] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 04/01/2019] [Indexed: 02/02/2023] Open
Abstract
Cognitive impairment in Alzheimer’s disease (AD) is usually accompanied by synaptic loss in both the hippocampus and neocortex. In the early stage of AD, amyloid β-induced synapse changes is the main reason, while in the later stage, the accumulation of Tau protein promotes synapse degeneration as the key factor leading to dementia. MicroRNA (miRNA) is closely related to the expression changes of many AD-related genes. One of the most abundant brain-enriched miRNAs is miR-132, which has been shown to regulate both neuron morphogenesis and plasticity. It has been reported that miR-132 is significantly reduced in the brains of Alzheimer’s patients. Genetic deletion of miR-132 in mice promotes Aβ deposition, leading to impaired memory and enhanced Tau pathology, but how the miRNA-mediated gene expression dysregulation contributes to AD pathology remains unclear. Here we found the possible downstream target of miR-132 by in silico analysis, namely C1q. C1q is the primary protein of classical complement cascade, which is highly expressed in the synaptic regions of the central nervous system in Alzheimer’s patients. However, it is not clear whether miR-132 plays a role in AD through regulating C1q. To address this question, the APP/PS1 transgenic mice were transfected with miR-132 and given C1 inhibitors. Behavior tests were conducted to assess memory and cognitive abilities seven days after administration. In addition, we analyzed the expression of PSD95, Synapsin-1 and phosphorylated (p)- Synapsin. We found that the expression levels of the synaptic proteins treated with miR-132 or C1INH were significantly increased compared with the AD group. Further RT-qPCR result suggested that miR-132 might regulate C1q expression in AD.
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Affiliation(s)
- Nan Xu
- Department of Anatomy, College of Basic Medical Sciences, China Medical University, Shenyang.
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93
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Sato Y, Okabe S. Nano-scale analysis of synapse morphology in an autism mouse model with 15q11-13 copy number variation using focused ion beam milling and scanning electron microscopy. Microscopy (Oxf) 2019; 68:122-132. [PMID: 30371805 DOI: 10.1093/jmicro/dfy128] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 09/26/2018] [Accepted: 10/09/2018] [Indexed: 02/07/2023] Open
Abstract
Circuit-level alternations in patients of autism spectrum disorder (ASD) is under active investigation and detailed characterization of synapse morphology in ASD model mice should be informative. We utilized focused ion beam milling and scanning electron microscopy (FIB-SEM) to obtain three-dimensional images of synapses in the layer 2/3 of the somatosensory cortex from a mouse model for ASD with human 15q11-13 chromosomal duplication (15q dup mice). We found a trend of higher spine density and a higher fraction of astrocytic contact with both spine and shaft synapses in 15q dup mice. Measurement of spine synapse structure indicated that the size of the post-synaptic density (PSD), spine head volume, spine head width and spine neck width were smaller in 15q dup mice. Categorization of spine synapses into five classes suggested a trend of less frequent mushroom spines in 15q dup mice. These results suggest relative increase in excitatory synapses with immature morphology but more astrocytic contacts in 15q dup mice, which may be linked to enhanced synapse turnover seen in ASD mouse models.
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Affiliation(s)
- Yuka Sato
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
| | - Shigeo Okabe
- Department of Cellular Neurobiology, Graduate School of Medicine, University of Tokyo, Tokyo, Japan
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94
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Smolen P, Baxter DA, Byrne JH. How can memories last for days, years, or a lifetime? Proposed mechanisms for maintaining synaptic potentiation and memory. ACTA ACUST UNITED AC 2019; 26:133-150. [PMID: 30992383 PMCID: PMC6478248 DOI: 10.1101/lm.049395.119] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Accepted: 03/12/2019] [Indexed: 01/24/2023]
Abstract
With memory encoding reliant on persistent changes in the properties of synapses, a key question is how can memories be maintained from days to months or a lifetime given molecular turnover? It is likely that positive feedback loops are necessary to persistently maintain the strength of synapses that participate in encoding. Such feedback may occur within signal-transduction cascades and/or the regulation of translation, and it may occur within specific subcellular compartments or within neuronal networks. Not surprisingly, numerous positive feedback loops have been proposed. Some posited loops operate at the level of biochemical signal-transduction cascades, such as persistent activation of Ca2+/calmodulin kinase II (CaMKII) or protein kinase Mζ. Another level consists of feedback loops involving transcriptional, epigenetic and translational pathways, and autocrine actions of growth factors such as BDNF. Finally, at the neuronal network level, recurrent reactivation of cell assemblies encoding memories is likely to be essential for late maintenance of memory. These levels are not isolated, but linked by shared components of feedback loops. Here, we review characteristics of some commonly discussed feedback loops proposed to underlie the maintenance of memory and long-term synaptic plasticity, assess evidence for and against their necessity, and suggest experiments that could further delineate the dynamics of these feedback loops. We also discuss crosstalk between proposed loops, and ways in which such interaction can facilitate the rapidity and robustness of memory formation and storage.
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Affiliation(s)
- Paul Smolen
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - Douglas A Baxter
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
| | - John H Byrne
- Department of Neurobiology and Anatomy, W. M. Keck Center for the Neurobiology of Learning and Memory, McGovern Medical School of the University of Texas Health Science Center at Houston, Houston, Texas 77030, USA
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95
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Martinsson I, Capetillo-Zarate E, Faideau M, Willén K, Esteras N, Frykman S, Tjernberg LO, Gouras GK. APP depletion alters selective pre- and post-synaptic proteins. Mol Cell Neurosci 2019; 95:86-95. [PMID: 30763689 DOI: 10.1016/j.mcn.2019.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 01/30/2019] [Accepted: 02/09/2019] [Indexed: 12/30/2022] Open
Abstract
The normal role of Alzheimer's disease (AD)-linked amyloid precursor protein (APP) in the brain remains incompletely understood. Previous studies have reported that lack of APP has detrimental effects on spines and electrophysiological parameters. APP has been described to be important in synaptic pruning during development. The effect of APP knockout on mature synapses is complicated by this role in development. We previously reported on differential changes in synaptic proteins and receptors in APP mutant AD transgenic compared to wild-type neurons, which revealed selective decreases in levels of pre- and post-synaptic proteins, including of surface glutamate receptors. In the present study, we undertook a similar analysis of synaptic composition but now in APP knockout compared to wild-type mouse neurons. Here we demonstrate alterations in levels of selective pre- and post-synaptic proteins and receptors in APP knockout compared to wild-type mouse primary neurons in culture and brains of mice in youth and adulthood. Remarkably, we demonstrate selective increases in levels of synaptic proteins, such as GluA1, in neurons with APP knockout and with RNAi knockdown, which tended to be opposite to the reductions seen in AD transgenic APP mutant compared to wild-type neurons. These data reinforce that APP is important for the normal composition of synapses.
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Affiliation(s)
- Isak Martinsson
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Estibaliz Capetillo-Zarate
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY, USA; Achucarro Basque Center for Neuroscience, CIBERNED and Departamento de Neurociencias, Universidad del País Vasco. Leioa, Spain; IKERBASQUE, Basque Foundation for Science, Bilbao, Spain
| | - Mathilde Faideau
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Katarina Willén
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Noemi Esteras
- Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY, USA
| | - Susanne Frykman
- Karolinska Institute, Dept. of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Lars O Tjernberg
- Karolinska Institute, Dept. of Neurobiology, Care Sciences and Society, Center for Alzheimer Research, Division of Neurogeriatrics, Huddinge, Sweden
| | - Gunnar K Gouras
- Experimental Dementia Research Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden; Department of Neurology and Neuroscience, Weill Cornell Medical College, New York, NY, USA.
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96
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Pang S, Li Y, Chen W, Li Y, Yang M, Zhao L, Shen Q, Cheng N, Wang Y, Lin X, Ma J, Wu H, Zhu G. Pb exposure reduces the expression of SNX6 and Homer1 in offspring rats and PC12 cells. Toxicology 2019; 416:23-29. [PMID: 30738087 DOI: 10.1016/j.tox.2019.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 01/24/2019] [Accepted: 02/04/2019] [Indexed: 11/25/2022]
Abstract
Lead (Pb) is a widespread environmental heavy metal toxicant and chronic Pb exposure can have irreversible effects on memory and cognitive function, which is closely related to dendritic spines. Studies have shown that SNX6 and Homer1 can regulate the growth of dendritic spines. We aimed to investigate the effect of Pb exposure on the dendritic spines in hippocampus, the expression of SNX6 and Homer1 in rats and PC12 cells. The animals were randomly divided to three groups: control group, low lead group and high lead group. PC12 cells were divided into 3 groups: 0 μM, 1 μM and 100 μM Pb acetate. The results showed that the Pb levels in blood and hippocampus of all exposure groups were significantly higher than that of the control group. The morphology of dendritic spines in hippocampus after Pb treatment was changed and the density of dendritic spines was reduced. The expression of SNX6 and Homer1 was decreased in Pb exposed groups compared with the control group. Furthermore, up-regulation of SNX6 expression could reverse the down-regulation of Pb exposure on Homer1. These results indicate that Pb exposure can reduce the expression of SNX6 and lead to a decrease in Homer1 expression, which affects the changes in dendritic spines causing learning and memory impairment.
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Affiliation(s)
- Shimin Pang
- Second Clinical Collage, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Yanshu Li
- Jiangxi Supervision and Inspection Center for Medical Devices, Nanchang 330029, PR China
| | - Wei Chen
- Laboratory Animal Science Center, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Yaobin Li
- Department of Anatomy, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Meiyuan Yang
- Department of Anatomy, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Lijuan Zhao
- Second Clinical Collage, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Qiwei Shen
- Second Clinical Collage, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Nuo Cheng
- Queen Marry Collage, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Ying Wang
- Queen Marry Collage, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Xuequn Lin
- Faculty of Nursing, Nanchang Insitude of technology, Nanchang 330006, PR China
| | - Jianmin Ma
- Department of Anatomy, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Honghao Wu
- Department of Anatomy, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China
| | - Gaochun Zhu
- Department of Anatomy, School of Medicine, Nanchang University, BaYi Road 461, Nanchang 330006, PR China.
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97
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Kinesin Family of Proteins Kif11 and Kif21B Act as Inhibitory Constraints of Excitatory Synaptic Transmission Through Distinct Mechanisms. Sci Rep 2018; 8:17419. [PMID: 30479371 PMCID: PMC6258692 DOI: 10.1038/s41598-018-35634-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 11/09/2018] [Indexed: 02/03/2023] Open
Abstract
Despite our understanding of the functions of the kinesin family of motor proteins (Kifs) in neurons, their specific roles in neuronal communication are less understood. To address this, by carrying out RNAi-mediated loss of function studies, we assessed the necessity of 18 Kifs in excitatory synaptic transmission in mouse primary hippocampal neurons prepared from both sexes. Our measurements of excitatory post-synaptic currents (EPSCs) have identified 7 Kifs that were found to be not critical and 11 Kifs that are essential for synaptic transmission by impacting either frequency or amplitude or both components of EPSCs. Intriguingly we found that knockdown of mitotic Kif4A and Kif11 and post-mitotic Kif21B resulted in an increase in EPSCs suggesting that they function as inhibitory constraints on synaptic transmission. Furthermore, Kifs (11, 21B, 13B) with distinct effects on synaptic transmission are expressed in the same hippocampal neuron. Mechanistically, unlike Kif21B, Kif11 requires the activity of pre-synaptic NMDARs. In addition, we find that Kif11 knockdown enhanced dendritic arborization, synapse number, expression of synaptic vesicle proteins synaptophysin and active zone protein Piccolo. Moreover, expression of Piccolo constrained Kif11 function in synaptic transmission. Together these results suggest that neurons are able to utilize specific Kifs as tools for calibrating synaptic function. These studies bring novel insights into the biology of Kifs and functioning of neural circuits.
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98
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Maclachlan C, Sahlender DA, Hayashi S, Molnár Z, Knott G. Block Face Scanning Electron Microscopy of Fluorescently Labeled Axons Without Using Near Infra-Red Branding. Front Neuroanat 2018; 12:88. [PMID: 30459565 PMCID: PMC6232369 DOI: 10.3389/fnana.2018.00088] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/08/2018] [Indexed: 11/23/2022] Open
Abstract
In this article, we describe the method that allows fluorescently tagged structures such as axons to be targeted for electron microscopy (EM) analysis without the need to convert their labels into electron dense stains, introduce any fiducial marks, or image large volumes at high resolution. We optimally preserve and stain the brain tissue for ultrastructural analysis and use natural landmarks, such as cell bodies and blood vessels, to locate neurites that had been imaged previously using confocal microscopy. The method relies on low and high magnification views taken with the light microscope, after fixation, to capture information of the tissue structure that can later be used to pinpoint the position of structures of interest in serial EM images. The examples shown here are td Tomato expressing cortico-thalamic axons in the posteromedial nucleus of the mouse thalamus, imaged in fixed tissue with confocal microscopy, and subsequently visualized with serial block-face EM (SBEM) and reconstructed into 3D models for analysis.
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Affiliation(s)
- Catherine Maclachlan
- BioEM Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Daniela A Sahlender
- BioEM Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Shuichi Hayashi
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom
| | - Graham Knott
- BioEM Facility, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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99
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Dukhinova M, Kuznetsova I, Kopeikina E, Veniaminova E, Yung AWY, Veremeyko T, Levchuk K, Barteneva NS, Wing-Ho KK, Yung WH, Liu JYH, Rudd J, Yau SSY, Anthony DC, Strekalova T, Ponomarev ED. Platelets mediate protective neuroinflammation and promote neuronal plasticity at the site of neuronal injury. Brain Behav Immun 2018; 74:7-27. [PMID: 30217533 DOI: 10.1016/j.bbi.2018.09.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Revised: 09/10/2018] [Accepted: 09/10/2018] [Indexed: 01/05/2023] Open
Abstract
It is generally accepted that inflammation within the CNS contributes to neurodegeneration after traumatic brain injury (TBI), but it is not clear how inflammation is initiated in the absence of infection and whether this neuroinflammation is predominantly beneficial or detrimental. We have previously found that brain-enriched glycosphingolipids within neuronal lipid rafts (NLR) induced platelet degranulation and secretion of neurotransmitters and pro-inflammatory factors. In the present study, we compared TBI-induced inflammation and neurodegeneration in wild-type vs. St3gal5 deficient (ST3-/-) mice that lack major CNS-specific glycosphingolipids. After TBI, microglial activation and CNS macrophage infiltration were substantially reduced in ST3-/- animals. However, ST3-/- mice had a larger area of CNS damage with marked neuronal/axonal loss. The interaction of platelets with NLR stimulated neurite growth, increased the number of PSD95-positive dendritic spines, and intensified neuronal activity. Adoptive transfer and blocking experiments provide further that platelet-derived serotonin and platelet activating factor plays a key role in the regulation of sterile neuroinflammation, hemorrhage and neuronal plasticity after TBI.
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Affiliation(s)
- Marina Dukhinova
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Inna Kuznetsova
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Ekaterina Kopeikina
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Ekaterina Veniaminova
- Department of Neuroscience, Maastricht University, Universiteitssingel 40, NL 6229ER, Maastricht, Netherlands; Institute of General Pathology and Pathophysiology, Baltiiskaya str, 8, Moscow, 125315, Russia; Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Laboratory of Psychiatric Neurobiology, Trubetskaya Street 8-2, 119991, Moscow, Russia
| | - Amanda W Y Yung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Tatyana Veremeyko
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Kseniia Levchuk
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Natasha S Barteneva
- Program in Cellular and Molecular Medicine, Children's Hospital Boston and Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Kenny Kam Wing-Ho
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Wing-Ho Yung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - Julia Y H Liu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong
| | - John Rudd
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong; Brain and Mind Institute, The Chinese University of Hong Kong, Shatin NT, Hong Kong
| | - Sonata S Y Yau
- Department of Rehabilitation Sciences, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong
| | - Daniel C Anthony
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, UK
| | - Tatyana Strekalova
- Department of Neuroscience, Maastricht University, Universiteitssingel 40, NL 6229ER, Maastricht, Netherlands; Institute of General Pathology and Pathophysiology, Baltiiskaya str, 8, Moscow, 125315, Russia; Sechenov First Moscow State Medical University, Institute of Molecular Medicine, Laboratory of Psychiatric Neurobiology, Trubetskaya Street 8-2, 119991, Moscow, Russia
| | - Eugene D Ponomarev
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong; Kunming Institute of Zoology and Chinese University of Hong Kong Joint Laboratory of Bioresources and Molecular Research of Common Diseases, Kunmin-Hong Kong, China.
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100
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Wiegert JS, Pulin M, Gee CE, Oertner TG. The fate of hippocampal synapses depends on the sequence of plasticity-inducing events. eLife 2018; 7:39151. [PMID: 30311904 PMCID: PMC6205809 DOI: 10.7554/elife.39151] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Accepted: 10/11/2018] [Indexed: 01/31/2023] Open
Abstract
Synapses change their strength in response to specific activity patterns. This functional plasticity is assumed to be the brain’s primary mechanism for information storage. We used optogenetic stimulation of rat hippocampal slice cultures to induce long-term potentiation (LTP), long-term depression (LTD), or both forms of plasticity in sequence. Two-photon imaging of spine calcium signals allowed us to identify stimulated synapses and to follow their fate for the next 7 days. We found that plasticity-inducing protocols affected the synapse’s chance for survival: LTP increased synaptic stability, LTD destabilized synapses, and the effect of the last stimulation protocol was dominant over earlier stimulations. Interestingly, most potentiated synapses were resistant to depression-inducing protocols delivered 24 hr later. Our findings suggest that activity-dependent changes in the transmission strength of individual synapses are transient, but have long-lasting consequences for synaptic lifetime.
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Affiliation(s)
- J Simon Wiegert
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Mauro Pulin
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,Research Group Synaptic Wiring and Information Processing, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christine Elizabeth Gee
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas G Oertner
- Institute for Synaptic Physiology, Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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