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Higa GSV, Viana FJC, Francis-Oliveira J, Cruvinel E, Franchin TS, Marcourakis T, Ulrich H, De Pasquale R. Serotonergic neuromodulation of synaptic plasticity. Neuropharmacology 2024; 257:110036. [PMID: 38876308 DOI: 10.1016/j.neuropharm.2024.110036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 05/15/2024] [Accepted: 06/11/2024] [Indexed: 06/16/2024]
Abstract
Synaptic plasticity constitutes a fundamental process in the reorganization of neural networks that underlie memory, cognition, emotional responses, and behavioral planning. At the core of this phenomenon lie Hebbian mechanisms, wherein frequent synaptic stimulation induces long-term potentiation (LTP), while less activation leads to long-term depression (LTD). The synaptic reorganization of neuronal networks is regulated by serotonin (5-HT), a neuromodulator capable of modify synaptic plasticity to appropriately respond to mental and behavioral states, such as alertness, attention, concentration, motivation, and mood. Lately, understanding the serotonergic Neuromodulation of synaptic plasticity has become imperative for unraveling its impact on cognitive, emotional, and behavioral functions. Through a comparative analysis across three main forebrain structures-the hippocampus, amygdala, and prefrontal cortex, this review discusses the actions of 5-HT on synaptic plasticity, offering insights into its role as a neuromodulator involved in emotional and cognitive functions. By distinguishing between plastic and metaplastic effects, we provide a comprehensive overview about the mechanisms of 5-HT neuromodulation of synaptic plasticity and associated functions across different brain regions.
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Affiliation(s)
- Guilherme Shigueto Vilar Higa
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil; Departamento de Bioquímica, Instituto de Química (USP), Butantã, São Paulo, SP, 05508-900, Brazil
| | - Felipe José Costa Viana
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - José Francis-Oliveira
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35233, USA
| | - Emily Cruvinel
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Thainá Soares Franchin
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Tania Marcourakis
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Ciências Farmacêuticas, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil
| | - Henning Ulrich
- Departamento de Bioquímica, Instituto de Química (USP), Butantã, São Paulo, SP, 05508-900, Brazil
| | - Roberto De Pasquale
- Laboratório de Neurofisiologia, Departamento de Fisiologia e Biofísica, Universidade de São Paulo, Butantã, São Paulo, SP, 05508-000, Brazil.
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Wiench L, Rizzo D, Sinay Z, Nacsa Z, Fuchs NV, König R. Role of PQBP1 in Pathogen Recognition-Impact on Innate Immunity. Viruses 2024; 16:1340. [PMID: 39205314 PMCID: PMC11360342 DOI: 10.3390/v16081340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Revised: 08/19/2024] [Accepted: 08/20/2024] [Indexed: 09/04/2024] Open
Abstract
The intrinsically disordered polyglutamine-binding protein 1 (PQBP1) has been linked to various cellular processes including transcription, alternative splicing, translation and innate immunity. Mutations in PQBP1 are causative for neurodevelopmental conditions collectively termed as the Renpenning syndrome spectrum. Intriguingly, cells of Renpenning syndrome patients exhibit a reduced innate immune response against human immunodeficiency virus 1 (HIV-1). PQBP1 is responsible for the initiation of a two-step recognition process of HIV-1 reverse-transcribed DNA products, ensuring a type 1 interferon response. Recent investigations revealed that PQBP1 also binds to the p17 protein of avian reovirus (ARV) and is affected by the ORF52 of Kaposi's sarcoma-associated herpesvirus (KSHV), possibly also playing a role in the innate immune response towards these RNA- and DNA-viruses. Moreover, PQBP1-mediated microglia activation in the context of tauopathies has been reported, highlighting the role of PQBP1 in sensing exogenous pathogenic species and innate immune response in the central nervous system. Its unstructured nature, the promiscuous binding of various proteins and its presence in various tissues indicate the versatile roles of PQBP1 in cellular regulation. Here, we systematically review the available data on the structure of PQBP1 and its cellular functions and interactome, as well as possible implications for innate immune responses and neurodegenerative disorders.
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Affiliation(s)
| | | | | | | | | | - Renate König
- Host-Pathogen Interactions, Paul-Ehrlich-Institut, Paul-Ehrlich-Str. 51–59, 63225 Langen, Germany
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3
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López-Merino E, Cuartero MI, Esteban JA, Briz V. Perinatal exposure to pesticides alters synaptic plasticity signaling and induces behavioral deficits associated with neurodevelopmental disorders. Cell Biol Toxicol 2023; 39:2089-2111. [PMID: 35137321 PMCID: PMC10547633 DOI: 10.1007/s10565-022-09697-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 01/26/2022] [Indexed: 12/17/2022]
Abstract
Increasing evidence from animal and epidemiological studies indicates that perinatal exposure to pesticides cause developmental neurotoxicity and may increase the risk for psychiatric disorders such as autism and intellectual disability. However, the underlying pathogenic mechanisms remain largely elusive. This work was aimed at testing the hypothesis that developmental exposure to different classes of pesticides hijacks intracellular neuronal signaling contributing to synaptic and behavioral alterations associated with neurodevelopmental disorders (NDD). Low concentrations of organochlorine (dieldrin, endosulfan, and chlordane) and organophosphate (chlorpyrifos and its oxon metabolite) pesticides were chronically dosed ex vivo (organotypic rat hippocampal slices) or in vivo (perinatal exposure in rats), and then biochemical, electrophysiological, behavioral, and proteomic studies were performed. All the pesticides tested caused prolonged activation of MAPK/ERK pathway in a concentration-dependent manner. Additionally, some of them impaired metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD). In the case of the pesticide chlordane, the effect was attributed to chronic modulation of MAPK/ERK signaling. These synaptic alterations were reproduced following developmental in vivo exposure to chlordane and chlorpyrifos-oxon, and were also associated with prototypical behavioral phenotypes of NDD, including impaired motor development, increased anxiety, and social and memory deficits. Lastly, proteomic analysis revealed that these pesticides differentially regulate the expression of proteins in the hippocampus with pivotal roles in brain development and synaptic signaling, some of which are associated with NDD. Based on these results, we propose a novel mechanism of synaptic dysfunction, involving chronic overactivation of MAPK and impaired mGluR-LTD, shared by different pesticides which may have important implications for NDD.
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Affiliation(s)
| | - María I Cuartero
- Neurovascular Pathophysiology Group, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - José A Esteban
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.
| | - Víctor Briz
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.
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4
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Mango D, Ledonne A. Updates on the Physiopathology of Group I Metabotropic Glutamate Receptors (mGluRI)-Dependent Long-Term Depression. Cells 2023; 12:1588. [PMID: 37371058 DOI: 10.3390/cells12121588] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/29/2023] Open
Abstract
Group I metabotropic glutamate receptors (mGluRI), including mGluR1 and mGluR5 subtypes, modulate essential brain functions by affecting neuronal excitability, intracellular calcium dynamics, protein synthesis, dendritic spine formation, and synaptic transmission and plasticity. Nowadays, it is well appreciated that the mGluRI-dependent long-term depression (LTD) of glutamatergic synaptic transmission (mGluRI-LTD) is a key mechanism by which mGluRI shapes connectivity in various cerebral circuitries, directing complex brain functions and behaviors, and that it is deranged in several neurological and psychiatric illnesses, including neurodevelopmental disorders, neurodegenerative diseases, and psychopathologies. Here, we will provide an updated overview of the physiopathology of mGluRI-LTD, by describing mechanisms of induction and regulation by endogenous mGluRI interactors, as well as functional physiological implications and pathological deviations.
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Affiliation(s)
- Dalila Mango
- School of Pharmacy, University of Rome "Tor Vergata", 00133 Rome, Italy
- Laboratory of Pharmacology of Synaptic Plasticity, European Brain Research Institute, 00161 Rome, Italy
| | - Ada Ledonne
- Department of Systems Medicine, University of Rome "Tor Vergata", 00133 Rome, Italy
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
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Lifelong changes of neurotransmitter receptor expression and debilitation of hippocampal synaptic plasticity following early postnatal blindness. Sci Rep 2022; 12:9142. [PMID: 35650390 PMCID: PMC9160005 DOI: 10.1038/s41598-022-13127-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 05/06/2022] [Indexed: 11/30/2022] Open
Abstract
In the weeks immediately after onset of sensory loss, extensive reorganization of both the cortex and hippocampus occurs. Two fundamental characteristics comprise widespread changes in the relative expression of GABA and glutamate receptors and debilitation of hippocampal synaptic plasticity. Here, we explored whether recovery from adaptive changes in the expression of plasticity-related neurotransmitter receptors and hippocampal synaptic plasticity occurs in the time-period of up to 12 months after onset of sensory loss. We compared receptor expression in CBA/J mice that develop hereditary blindness, with CBA/CaOlaHsd mice that have intact vision and no deficits in other sensory modalities throughout adulthood. GluN1-subunit expression was reduced and the GluN2A:GluN2B ratio was persistently altered in cortex and hippocampus. GABA-receptor expression was decreased and metabotropic glutamate receptor expression was altered. Hippocampal synaptic plasticity was persistently compromised in vivo. But although LTP in blind mice was chronically impaired throughout adulthood, a recovery of the early phase of LTP became apparent when the animals reached 12 months of age. These data show that cortical and hippocampal adaptation to early postnatal blindness progresses into advanced adulthood and is a process that compromises hippocampal function. A partial recovery of hippocampal synaptic plasticity emerges in advanced adulthood, however.
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Sanderson TM, Ralph LT, Amici M, Ng AN, Kaang BK, Zhuo M, Kim SJ, Georgiou J, Collingridge GL. Selective Recruitment of Presynaptic and Postsynaptic Forms of mGluR-LTD. Front Synaptic Neurosci 2022; 14:857675. [PMID: 35615440 PMCID: PMC9126322 DOI: 10.3389/fnsyn.2022.857675] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 04/20/2022] [Indexed: 12/03/2022] Open
Abstract
In area CA1 of the hippocampus, long-term depression (LTD) can be induced by activating group I metabotropic glutamate receptors (mGluRs), with the selective agonist DHPG. There is evidence that mGluR-LTD can be expressed by either a decrease in the probability of neurotransmitter release [P(r)] or by a change in postsynaptic AMPA receptor number. However, what determines the locus of expression is unknown. We investigated the expression mechanisms of mGluR-LTD using either a low (30 μM) or a high (100 μM) concentration of (RS)-DHPG. We found that 30 μM DHPG generated presynaptic LTD that required the co-activation of NMDA receptors, whereas 100 μM DHPG resulted in postsynaptic LTD that was independent of the activation of NMDA receptors. We found that both forms of LTD occur at the same synapses and that these may constitute the population with the lowest basal P(r). Our results reveal an unexpected complexity to mGluR-mediated synaptic plasticity in the hippocampus.
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Affiliation(s)
- Thomas M. Sanderson
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Liam T. Ralph
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Mascia Amici
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Ai Na Ng
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Bong-Kiun Kaang
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
| | - Min Zhuo
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Sang Jeong Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, South Korea
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
| | - Graham L. Collingridge
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Sinai Health System, Toronto, ON, Canada
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul, South Korea
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, Canada
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
- *Correspondence: Graham L. Collingridge,
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Stacho M, Manahan-Vaughan D. The Intriguing Contribution of Hippocampal Long-Term Depression to Spatial Learning and Long-Term Memory. Front Behav Neurosci 2022; 16:806356. [PMID: 35548697 PMCID: PMC9084281 DOI: 10.3389/fnbeh.2022.806356] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 03/10/2022] [Indexed: 01/03/2023] Open
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) comprise the principal cellular mechanisms that fulfill established criteria for the physiological correlates of learning and memory. Traditionally LTP, that increases synaptic weights, has been ascribed a prominent role in learning and memory whereas LTD, that decreases them, has often been relegated to the category of "counterpart to LTP" that serves to prevent saturation of synapses. In contradiction of these assumptions, studies over the last several years have provided functional evidence for distinct roles of LTD in specific aspects of hippocampus-dependent associative learning and information encoding. Furthermore, evidence of the experience-dependent "pruning" of excitatory synapses, the majority of which are located on dendritic spines, by means of LTD has been provided. In addition, reports exist of the temporal and physical restriction of LTP in dendritic compartments by means of LTD. Here, we discuss the role of LTD and LTP in experience-dependent information encoding based on empirical evidence derived from conjoint behavioral and electrophysiological studies conducted in behaving rodents. We pinpoint the close interrelation between structural modifications of dendritic spines and the occurrence of LTP and LTD. We report on findings that support that whereas LTP serves to acquire the general scheme of a spatial representation, LTD enables retention of content details. We argue that LTD contributes to learning by engaging in a functional interplay with LTP, rather than serving as its simple counterpart, or negator. We propose that similar spatial experiences that share elements of neuronal representations can be modified by means of LTD to enable pattern separation. Therewith, LTD plays a crucial role in the disambiguation of similar spatial representations and the prevention of generalization.
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Stacho M, Manahan-Vaughan D. Mechanistic flexibility of the retrosplenial cortex enables its contribution to spatial cognition. Trends Neurosci 2022; 45:284-296. [DOI: 10.1016/j.tins.2022.01.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 12/17/2021] [Accepted: 01/27/2022] [Indexed: 12/20/2022]
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Di Cicco G, Marzano E, Iacovelli L, Celli R, van Luijtelaar G, Nicoletti F, Ngomba RT, Wall MJ. Group I metabotropic glutamate receptor-mediated long term depression is disrupted in the hippocampus of WAG/Rij rats modelling absence epilepsy. Neuropharmacology 2021; 196:108686. [PMID: 34197893 DOI: 10.1016/j.neuropharm.2021.108686] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Revised: 06/16/2021] [Accepted: 06/17/2021] [Indexed: 11/19/2022]
Abstract
Absence epilepsy is frequently associated with cognitive dysfunction, although the underlying mechanisms are not well understood. Here we report that some forms of hippocampal synaptic plasticity are abnormal in symptomatic Wistar Albino Glaxo/Rijswijk (WAG/Rij) rats. Metabotropic Glu 1/5 receptor-mediated long term depression (LTD) at Schaffer collateral CA1 synapses is significantly reduced in symptomatic, 5-6 months old WAG/Rij rats compared to age-matched non epileptic control rats. There were no significant changes in mGlu1/5-dependent LTD in pre-symptomatic, 4-6 weeks old WAG/Rij rats compared to age matched controls. The changes in LTD found in symptomatic WAG/Rij forms are not indicative of general deficits in all forms of synaptic plasticity as long term potentiation (LTP) was unchanged. Immunoblot analysis of hippocampal tissue showed a significant reduction in mGlu5 receptor expression, a trend to an increase in pan Homer protein levels and a decrease in GluA1 receptor expression in the hippocampus of symptomatic WAG/Rij rats vs non-epileptic control rats. There were no changes in mGlu1α receptor or GluA2 protein levels. These findings suggest that abnormalities in hippocampal mGlu5 receptor-dependent synaptic plasticity are associated with the pathological phenotype of WAG/Rij rats. This lays the groundwork for the study of mGlu5 receptors as a candidate drug target for the treatment of cognitive dysfunction linked to absence epilepsy.
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Affiliation(s)
- Gabriele Di Cicco
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | - Emanuela Marzano
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | - Luisa Iacovelli
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy
| | | | | | - Ferdinando Nicoletti
- Departments of Physiology and Pharmacology, University Sapienza of Rome, Italy; IRCCS Neuromed, Pozzilli, Italy
| | - Richard T Ngomba
- University of Lincoln, School of Pharmacy Lincoln, United Kingdom; and, Coventry, UK.
| | - Mark J Wall
- School of Life Sciences, University of Warwick, Coventry, UK.
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Bin Ibrahim MZ, Benoy A, Sajikumar S. Long-term plasticity in the hippocampus: maintaining within and 'tagging' between synapses. FEBS J 2021; 289:2176-2201. [PMID: 34109726 DOI: 10.1111/febs.16065] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 05/15/2021] [Accepted: 06/01/2021] [Indexed: 12/11/2022]
Abstract
Synapses between neurons are malleable biochemical structures, strengthening and diminishing over time dependent on the type of information they receive. This phenomenon known as synaptic plasticity underlies learning and memory, and its different forms, long-term potentiation (LTP) and long-term depression (LTD), perform varied cognitive roles in reinforcement, relearning and associating memories. Moreover, both LTP and LTD can exist in an early transient form (early-LTP/LTD) or a late persistent form (late-LTP/LTD), which are triggered by different induction protocols, and also differ in their dependence on protein synthesis and the involvement of key molecular players. Beyond homosynaptic modifications, synapses can also interact with one another. This is encapsulated in the synaptic tagging and capture hypothesis (STC), where synapses expressing early-LTP/LTD present a 'tag' that can capture the protein synthesis products generated during a temporally proximal late-LTP/LTD induction. This 'tagging' phenomenon forms the framework of synaptic interactions in various conditions and accounts for the cellular basis of the time-dependent associativity of short-lasting and long-lasting memories. All these synaptic modifications take place under controlled neuronal conditions, regulated by subcellular elements such as epigenetic regulation, proteasomal degradation and neuromodulatory signals. Here, we review current understanding of the different forms of synaptic plasticity and its regulatory mechanisms in the hippocampus, a brain region critical for memory formation. We also discuss expression of plasticity in hippocampal CA2 area, a long-overlooked narrow hippocampal subfield and the behavioural correlate of STC. Lastly, we put forth perspectives for an integrated view of memory representation in synapses.
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Affiliation(s)
- Mohammad Zaki Bin Ibrahim
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore
| | - Amrita Benoy
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore
| | - Sreedharan Sajikumar
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Life Sciences Institute Neurobiology Programme, National University of Singapore, Singapore.,Healthy Longevity Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Feld GB, Bergmann TO, Alizadeh-Asfestani M, Stuke V, Wriede JP, Soekadar S, Born J. Specific changes in sleep oscillations after blocking human metabotropic glutamate receptor 5 in the absence of altered memory function. J Psychopharmacol 2021; 35:652-667. [PMID: 33899580 DOI: 10.1177/02698811211005627] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Sleep consolidates declarative memory by repeated replay linked to the cardinal oscillations of non-rapid eye movement (NonREM) sleep. However, there is so far little evidence of classical glutamatergic plasticity induced by this replay. Rather, we have previously reported that blocking N-methyl-D-aspartate (NMDA) or α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors does not affect sleep-dependent consolidation of declarative memory. AIMS The aim of this study was to investigate the role of metabotropic glutamate receptor 5 (mGluR5) in memory processing during sleep. METHODS In two placebo-controlled within-subject crossover experiments with 20 healthy humans each, we used fenobam to block mGluR5 during sleep. In Experiment I, participants learned word-pairs (declarative task) and a finger sequence (procedural task) in the evening, then received the drug and recall was tested the next morning. To cover possible effects on synaptic renormalization processes during sleep, in Experiment II participants learned new word-pairs in the morning after sleep. RESULTS/OUTCOMES Surprisingly, fenobam neither reduced retention of memory across sleep nor new learning after sleep, although it severely altered sleep architecture and memory-relevant EEG oscillations. In NonREM sleep, fenobam suppressed 12-15 Hz spindles but augmented 2-4 Hz delta waves, whereas in rapid eye movement (REM) sleep it suppressed 4-8 Hz theta and 16-22 Hz beta waves. Notably, under fenobam NonREM spindles became more consistently phase-coupled to the slow oscillation. CONCLUSIONS/INTERPRETATIONS Our findings indicate that mGluR5-related plasticity is not essential for memory processing during sleep, even though mGlurR5 are strongly implicated in the regulation of the cardinal sleep oscillations.
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Affiliation(s)
- Gordon B Feld
- Department of Clinical Psychology, University of Heidelberg, Mannheim, Germany.,Department of Addiction Behavior and Addiction Medicine, University of Heidelberg, Mannheim, Germany.,Department of Psychiatry and Psychotherapy, University of Heidelberg, Mannheim, Germany.,Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Til O Bergmann
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Leibniz Institute for Resilience Research (LIR), Mainz, Germany.,Department of Neurology & Stroke, and Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.,Neuroimaging Center (NIC), Johannes Gutenberg University Medical Center, Mainz, Germany
| | - Marjan Alizadeh-Asfestani
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Viola Stuke
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan-Philipp Wriede
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Surjo Soekadar
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute of Medical Psychology and Behavioral Neurobiology, University of Tübingen, Tübingen, Germany.,Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD), University Medical Centre Tübingen, Tübingen, Germany
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12
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Lopes da Cunha P, Tintorelli R, Correa J, Budriesi P, Viola H. Behavioral tagging as a mechanism for aversive-memory formation under acute stress. Eur J Neurosci 2021; 55:2651-2665. [PMID: 33914357 DOI: 10.1111/ejn.15249] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 04/01/2021] [Accepted: 04/15/2021] [Indexed: 02/03/2023]
Abstract
The behavioral tagging (BT) hypothesis postulates that a weak learning experience, which only induces short-term memory, may benefit from another event that provides plasticity-related proteins (PRPs) to establish a long-lasting memory. According to BT, the weak experience sets a transient learning tag at specific activated sites, and its temporal and spatial convergence with the PRPs allows the long-term memory (LTM) formation. In this work, rats were subjected to a weak inhibitory avoidance (IAw) training and we observed that acute stress (elevated platform, EP) experienced 1 hr before IAw promoted IA-LTM formation. This effect was dependent on glucocorticoid-receptor activity as well as protein synthesis in the dorsal hippocampus. However, the same stress has negative effects on IA-LTM formation when training is strong, probably by competing for necessary PRPs. Furthermore, our experiments showed that EP immediately after training did not impair the setting of the learning tag and even facilitated IA-LTM formation. These findings reveal different impacts of a given acute stressful experience on the formation of an aversive memory that could be explained by BT processes.
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Affiliation(s)
- Pamela Lopes da Cunha
- Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Biología Celular y Neurociencias "Dr Eduardo De Robertis" (IBCN), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Ramiro Tintorelli
- Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Biología Celular y Neurociencias "Dr Eduardo De Robertis" (IBCN), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Julieta Correa
- Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Biología Celular y Neurociencias "Dr Eduardo De Robertis" (IBCN), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Pablo Budriesi
- Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina.,Instituto de Biología Celular y Neurociencias "Dr Eduardo De Robertis" (IBCN), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Haydee Viola
- Instituto de Biología Celular y Neurociencias "Dr Eduardo De Robertis" (IBCN), CONICET, Universidad de Buenos Aires, Buenos Aires, Argentina.,Departamento de Fisiología, Biología Molecular y Celular "Dr. Hector Maldonado" (FBMC), Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
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Shen Y, Zhang ZC, Cheng S, Liu A, Zuo J, Xia S, Liu X, Liu W, Jia Z, Xie W, Han J. PQBP1 promotes translational elongation and regulates hippocampal mGluR-LTD by suppressing eEF2 phosphorylation. Mol Cell 2021; 81:1425-1438.e10. [PMID: 33662272 DOI: 10.1016/j.molcel.2021.01.032] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 12/07/2020] [Accepted: 01/21/2021] [Indexed: 10/22/2022]
Abstract
Eukaryotic elongation factor 2 (eEF2) mediates translocation of peptidyl-tRNA from the ribosomal A site to the P site to promote translational elongation. Its phosphorylation on Thr56 by its single known kinase eEF2K inactivates it and inhibits translational elongation. Extensive studies have revealed that different signal cascades modulate eEF2K activity, but whether additional factors regulate phosphorylation of eEF2 remains unclear. Here, we find that the X chromosome-linked intellectual disability protein polyglutamine-binding protein 1 (PQBP1) specifically binds to non-phosphorylated eEF2 and suppresses eEF2K-mediated phosphorylation at Thr56. Loss of PQBP1 significantly reduces general protein synthesis by suppressing translational elongation. Moreover, we show that PQBP1 regulates hippocampal metabotropic glutamate receptor-dependent long-term depression (mGluR-LTD) and mGluR-LTD-associated behaviors by suppressing eEF2K-mediated phosphorylation. Our results identify PQBP1 as a novel regulator in translational elongation and mGluR-LTD, and this newly revealed regulator in the eEF2K/eEF2 pathway is also an excellent therapeutic target for various disease conditions, such as neural diseases, virus infection, and cancer.
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Affiliation(s)
- Yuqian Shen
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Zi Chao Zhang
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China.
| | - Shanshan Cheng
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - An Liu
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Jian Zuo
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Shuting Xia
- Institute of Neuroscience, Soochow University, Suzhou 215000, China
| | - Xian Liu
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Wenhua Liu
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Zhengping Jia
- Neurosciences and Mental Health Program, Hospital for Sick Children, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Wei Xie
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China
| | - Junhai Han
- School of Life Science and Technology, Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China; Co-innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu 226001, China; Department of Neurology, Affiliated ZhongDa Hospital, Institute of Neuropsychiatry, Southeast University, Nanjing, Jiangsu 210009, China.
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Ledonne A, Mercuri NB. Insights on the Functional Interaction between Group 1 Metabotropic Glutamate Receptors (mGluRI) and ErbB Receptors. Int J Mol Sci 2020; 21:ijms21217913. [PMID: 33114459 PMCID: PMC7662933 DOI: 10.3390/ijms21217913] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2020] [Revised: 10/23/2020] [Accepted: 10/23/2020] [Indexed: 11/16/2022] Open
Abstract
It is well-appreciated that phosphorylation is an essential post-translational mechanism of regulation for several proteins, including group 1 metabotropic glutamate receptors (mGluRI), mGluR1, and mGluR5 subtypes. While contributions of various serine/threonine protein kinases on mGluRI modulation have been recognized, the functional role of tyrosine kinases (TKs) is less acknowledged. Here, while describing current evidence supporting that mGluRI are targets of TKs, we mainly focus on the modulatory roles of the ErbB tyrosine kinases receptors—activated by the neurotrophic factors neuregulins (NRGs)—on mGluRI function. Available evidence suggests that mGluRI activity is tightly dependent on ErbB signaling, and that ErbB’s modulation profoundly influences mGluRI-dependent effects on neurotransmission, neuronal excitability, synaptic plasticity, and learning and memory processes.
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Affiliation(s)
- Ada Ledonne
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
- Correspondence: ; Tel.: +39-06-50170-3160
| | - Nicola B. Mercuri
- Department of Experimental Neuroscience, IRCCS Fondazione Santa Lucia, 00143 Rome, Italy
- Department of Systems Medicine, Università di Roma “Tor Vergata”, 00133 Rome, Italy;
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15
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The medial prefrontal cortex - hippocampus circuit that integrates information of object, place and time to construct episodic memory in rodents: Behavioral, anatomical and neurochemical properties. Neurosci Biobehav Rev 2020; 113:373-407. [PMID: 32298711 DOI: 10.1016/j.neubiorev.2020.04.007] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 02/25/2020] [Accepted: 04/06/2020] [Indexed: 12/31/2022]
Abstract
Rats and mice have been demonstrated to show episodic-like memory, a prototype of episodic memory, as defined by an integrated memory of the experience of an object or event, in a particular place and time. Such memory can be assessed via the use of spontaneous object exploration paradigms, variably designed to measure memory for object, place, temporal order and object-location inter-relationships. We review the methodological properties of these tests, the neurobiology about time and discuss the evidence for the involvement of the medial prefrontal cortex (mPFC), entorhinal cortex (EC) and hippocampus, with respect to their anatomy, neurotransmitter systems and functional circuits. The systematic analysis suggests that a specific circuit between the mPFC, lateral EC and hippocampus encodes the information for event, place and time of occurrence into the complex episodic-like memory, as a top-down regulation from the mPFC onto the hippocampus. This circuit can be distinguished from the neuronal component memory systems for processing the individual information of object, time and place.
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16
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Beckmann D, Feldmann M, Shchyglo O, Manahan-Vaughan D. Hippocampal Synaptic Plasticity, Spatial Memory, and Neurotransmitter Receptor Expression Are Profoundly Altered by Gradual Loss of Hearing Ability. Cereb Cortex 2020; 30:4581-4596. [PMID: 32202614 PMCID: PMC7325716 DOI: 10.1093/cercor/bhaa061] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Revised: 01/20/2020] [Accepted: 02/12/2020] [Indexed: 12/27/2022] Open
Abstract
Sensory information comprises the substrate from which memories are created. Memories of spatial sensory experience are encoded by means of synaptic plasticity in the hippocampus. Hippocampal dependency on sensory information is highlighted by the fact that sudden and complete loss of a sensory modality results in an impairment of hippocampal function that persists for months. Effects are accompanied by extensive changes in the expression of neurotransmitter receptors in cortex and hippocampus, consistent with a substantial adaptive reorganization of cortical function. Whether gradual sensory loss affects hippocampal function is unclear. Progressive age-dependent hearing loss (presbycusis) is a risk factor for cognitive decline. Here, we scrutinized C57BL/6 mice that experience hereditary and cumulative deafness starting in young adulthood. We observed that 2–4 months postnatally, increases in the cortical and hippocampal expression of GluN2A and GluN2B subunits of the N-methyl-D-aspartate receptor occurred compared to control mice that lack sensory deficits. Furthermore, GABA and metabotropic glutamate receptor expression were significantly altered. Hippocampal synaptic plasticity was profoundly impaired and mice exhibited significant deficits in spatial memory. These data show that during cortical adaptation to cumulative loss of hearing, plasticity-related neurotransmitter expression is extensively altered in the cortex and hippocampus. Furthermore, cumulative sensory loss compromises hippocampal function.
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Affiliation(s)
- Daniela Beckmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Mirko Feldmann
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
| | - Olena Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum 44780, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum 44780, Germany
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17
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Ledonne A, Mercuri NB. On the Modulatory Roles of Neuregulins/ErbB Signaling on Synaptic Plasticity. Int J Mol Sci 2019; 21:ijms21010275. [PMID: 31906113 PMCID: PMC6981567 DOI: 10.3390/ijms21010275] [Citation(s) in RCA: 30] [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: 12/09/2019] [Revised: 12/27/2019] [Accepted: 12/29/2019] [Indexed: 12/14/2022] Open
Abstract
Neuregulins (NRGs) are a family of epidermal growth factor-related proteins, acting on tyrosine kinase receptors of the ErbB family. NRGs play an essential role in the development of the nervous system, since they orchestrate vital functions such as cell differentiation, axonal growth, myelination, and synapse formation. They are also crucially involved in the functioning of adult brain, by directly modulating neuronal excitability, neurotransmission, and synaptic plasticity. Here, we provide a review of the literature documenting the roles of NRGs/ErbB signaling in the modulation of synaptic plasticity, focusing on evidence reported in the hippocampus and midbrain dopamine (DA) nuclei. The emerging picture shows multifaceted roles of NRGs/ErbB receptors, which critically modulate different forms of synaptic plasticity (LTP, LTD, and depotentiation) affecting glutamatergic, GABAergic, and DAergic synapses, by various mechanisms. Further, we discuss the relevance of NRGs/ErbB-dependent synaptic plasticity in the control of brain processes, like learning and memory and the known involvement of NRGs/ErbB signaling in the modulation of synaptic plasticity in brain’s pathological conditions. Current evidence points to a central role of NRGs/ErbB receptors in controlling glutamatergic LTP/LTD and GABAergic LTD at hippocampal CA3–CA1 synapses, as well as glutamatergic LTD in midbrain DA neurons, thus supporting that NRGs/ErbB signaling is essential for proper brain functions, cognitive processes, and complex behaviors. This suggests that dysregulated NRGs/ErbB-dependent synaptic plasticity might contribute to mechanisms underlying different neurological and psychiatric disorders.
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Affiliation(s)
- Ada Ledonne
- Department of Experimental Neuroscience, Santa Lucia Foundation, Via del Fosso di Fiorano, no 64, 00143 Rome, Italy;
- Correspondence: ; Tel.: +3906-501703160; Fax: +3906-501703307
| | - Nicola B. Mercuri
- Department of Experimental Neuroscience, Santa Lucia Foundation, Via del Fosso di Fiorano, no 64, 00143 Rome, Italy;
- Department of Systems Medicine, University of Rome “Tor Vergata”, Via Montpellier no 1, 00133 Rome, Italy
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18
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Neyman S, Braunewell KH, O'Connell KE, Dev KK, Manahan-Vaughan D. Inhibition of the Interaction Between Group I Metabotropic Glutamate Receptors and PDZ-Domain Proteins Prevents Hippocampal Long-Term Depression, but Not Long-Term Potentiation. Front Synaptic Neurosci 2019; 11:13. [PMID: 31057390 PMCID: PMC6482240 DOI: 10.3389/fnsyn.2019.00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/04/2019] [Indexed: 01/07/2023] Open
Abstract
The group I metabotropic glutamate (mGlu) receptor subtypes, mGlu1 and mGlu5, strongly regulate hippocampal synaptic plasticity. Both harbor PSD-95/discs-large/ZO-1 (PDZ) motifs at their extreme carboxyl terminals, which allow interaction with the PDZ domain of Tamalin, regulate the cell surface expression of group I mGlu receptors, and may modulate their coupling to signaling proteins. We investigated the functional role of this interaction in hippocampal long-term depression (LTD). Acute intracerebral treatment of adult rats with a cell-permeable PDZ-blocking peptide (pep-mGluR-STL), designed to competitively inhibit the interaction between Tamalin and group 1 mGlu receptors, prevented expression of LTD in the hippocampal CA1 region without affecting long-term potentiation (LTP) or basal synaptic transmission. Pep-mGluR-STL prevented facilitation by the group I mGlu receptor agonist, (S)-3,5-Dihydroxyphenylglycine (DHPG), and the mGlu5 agonist, (R,S)-2-chloro-5-Hydroxyphenylglycine (CHPG), of short-term depression (STD) into LTD, suggesting that Tamalin preferentially acts by mediating signaling through mGlu5. These data support that Tamalin is essential for the persistent expression of LTD and that it subserves the effective signaling of group 1 mGlu receptors.
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Affiliation(s)
- Sergey Neyman
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Karl-Heinz Braunewell
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Kara E O'Connell
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
| | - Kumlesh K Dev
- Drug Development, School of Medicine, Faculty of Health Sciences, Trinity College Dublin, Dublin, Ireland
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19
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Sanderson TM, Bradley CA, Georgiou J, Hong YH, Ng AN, Lee Y, Kim HD, Kim D, Amici M, Son GH, Zhuo M, Kim K, Kaang BK, Kim SJ, Collingridge GL. The Probability of Neurotransmitter Release Governs AMPA Receptor Trafficking via Activity-Dependent Regulation of mGluR1 Surface Expression. Cell Rep 2018; 25:3631-3646.e3. [PMID: 30590038 PMCID: PMC6315206 DOI: 10.1016/j.celrep.2018.12.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 09/28/2018] [Accepted: 12/03/2018] [Indexed: 12/14/2022] Open
Abstract
A major mechanism contributing to synaptic plasticity involves alterations in the number of AMPA receptors (AMPARs) expressed at synapses. Hippocampal CA1 synapses, where this process has been most extensively studied, are highly heterogeneous with respect to their probability of neurotransmitter release, P(r). It is unknown whether there is any relationship between the extent of plasticity-related AMPAR trafficking and the initial P(r) of a synapse. To address this question, we induced metabotropic glutamate receptor (mGluR) dependent long-term depression (mGluR-LTD) and assessed AMPAR trafficking and P(r) at individual synapses, using SEP-GluA2 and FM4-64, respectively. We found that either pharmacological or synaptic activation of mGluR1 reduced synaptic SEP-GluA2 in a manner that depends upon P(r); this process involved an activity-dependent reduction in surface mGluR1 that selectively protects high-P(r) synapses from synaptic weakening. Consequently, the extent of postsynaptic plasticity can be pre-tuned by presynaptic activity.
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Affiliation(s)
- Thomas M Sanderson
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; Neuroscience Research Institute, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea; School of Physiology, Pharmacology & Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Clarrisa A Bradley
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; Neuroscience & Mental Health Program, The Hospital for Sick Children, Toronto, ON, Canada
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada
| | - Yun Hwa Hong
- Neuroscience Research Institute, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea; Department of Physiology, Seoul National University College of Medicine, 28, Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea
| | - Ai Na Ng
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
| | - Yeseul Lee
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; School of Physiology, Pharmacology & Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
| | - Hee-Dae Kim
- Department of Brain and Cognitive Sciences, DGIST, and Korea Brain Institute (KBRI), Daegu, 41068, Korea
| | - Doyeon Kim
- Department of Brain and Cognitive Sciences, DGIST, and Korea Brain Institute (KBRI), Daegu, 41068, Korea
| | - Mascia Amici
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK
| | - Gi Hoon Son
- Department of Biomedical Sciences, Korea University College of Medicine, Seoul 136-705, Seoul, Korea
| | - Min Zhuo
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada; Department of Biological Sciences, College of Natural Sciences, Seoul National University, Building 504, Room 202, 599 Gwanangno, Gwanak-gu 151-747, Seoul, Korea; Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Kyungjin Kim
- Department of Brain and Cognitive Sciences, DGIST, and Korea Brain Institute (KBRI), Daegu, 41068, Korea
| | - Bong-Kiun Kaang
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; Department of Biological Sciences, College of Natural Sciences, Seoul National University, Building 504, Room 202, 599 Gwanangno, Gwanak-gu 151-747, Seoul, Korea; Center for Neuron and Disease, Frontier Institutes of Science and Technology, Xi'an Jiaotong University, Xi'an, 710049, China
| | - Sang Jeong Kim
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; Neuroscience Research Institute, Seoul National University College of Medicine, 28 Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea; Department of Physiology, Seoul National University College of Medicine, 28, Yeongeon-dong, Jongno-gu, Seoul 110-799, Korea.
| | - Graham L Collingridge
- Department of Brain and Cognitive Sciences, College of Natural Sciences, Seoul National University, Seoul 151-746, Korea; School of Physiology, Pharmacology & Neuroscience, University of Bristol, Dorothy Hodgkin Building, Whitson Street, Bristol BS1 3NY, UK; Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, ON M5G 1X5, Canada; Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.
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20
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Gimse K, Gorzek RC, Olin A, Osting S, Burger C. Hippocampal Homer1b/c is necessary for contextual fear conditioning and group I metabotropic glutamate receptor mediated long-term depression. Neurobiol Learn Mem 2018; 156:17-23. [PMID: 30336208 PMCID: PMC6226007 DOI: 10.1016/j.nlm.2018.10.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 10/08/2018] [Accepted: 10/11/2018] [Indexed: 01/24/2023]
Abstract
Coiled-coil forms of Homer1, including Homer1b and c (Homer1b/c) have been shown to play a role in hippocampal learning and memory and synaptic plasticity. We have previously found that overexpression of hippocampal Homer1c is sufficient to rescue learning and memory ability in aged learning impaired rats and in Homer1 knockout (KO) mice, and to rescue group I metabotropic glutamate receptor (mGluR1/5) mediated long-term potentiation in KO mice. Here, to determine if Homer1b/c is necessary for successful learning and memory we have utilized a rAAV5 vector expressing a Homer1b/c-targeting short hairpin RNA to knock down the expression of hippocampal Homer1b/c in adult 4-6-month old male Sprague Dawley rats. We have found that reduced hippocampal Homer1b/c expression elicits significant learning deficits in contextual fear conditioning, but not in the Morris water maze or novel object recognition tasks. Furthermore, we demonstrate that reduced hippocampal Homer1b/c is sufficient to completely block mGluR1/5 mediated long-term depression in the Schaffer collateral pathway. These results support a significant role for Homer1b/c in learning and synaptic plasticity; however, the exact role of each of these two protein isoforms in learning and memory remains elusive.
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Affiliation(s)
- Kirstan Gimse
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Medical Sciences Center, 1300 University Ave, Room 73 Bardeen, Madison, WI 53706, USA
| | - Ryan C Gorzek
- College of Letters and Science, University of Wisconsin, Madison, WI, USA
| | - Andrew Olin
- Department of Neurology, University of Wisconsin, Madison, WI, USA
| | - Sue Osting
- Department of Neurology, University of Wisconsin, Madison, WI, USA
| | - Corinna Burger
- Cellular and Molecular Pathology Graduate Program, University of Wisconsin-Madison, Medical Sciences Center, 1300 University Ave, Room 73 Bardeen, Madison, WI 53706, USA; Department of Neurology, University of Wisconsin, Madison, WI, USA.
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mTORC2, but not mTORC1, is required for hippocampal mGluR-LTD and associated behaviors. Nat Neurosci 2018; 21:799-802. [PMID: 29786082 PMCID: PMC6467217 DOI: 10.1038/s41593-018-0156-7] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 04/19/2018] [Indexed: 01/03/2023]
Abstract
The mechanistic target of rapamycin complex 1 (mTORC1) has been reported to be necessary for metabotropic glutamate receptor-mediated long-term depression (mGluR-LTD). Here we found that mTORC1-deficient mice exhibit normal hippocampal mGluR-LTD and associated behaviors. Moreover, rapamycin blocks mGluR-LTD in mTORC1-deficient mice. However, both rapamycin and mGluR activation regulate mTOR complex 2 (mTORC2) activity, and mTORC2-deficient mice show impaired mGluR-LTD and associated behaviors. Thus, mTORC2 is a major regulator of mGluR-LTD.
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22
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Wang W, Duclot F, Groveman BR, Carrier N, Qiao H, Fang XQ, Wang H, Xin W, Jiang XH, Salter MW, Ding XS, Kabbaj M, Yu XM. Hippocampal protein kinase D1 is necessary for DHPG-induced learning and memory impairments in rats. PLoS One 2018; 13:e0195095. [PMID: 29614089 PMCID: PMC5882104 DOI: 10.1371/journal.pone.0195095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 03/18/2018] [Indexed: 11/18/2022] Open
Abstract
Background Understanding molecular mechanisms underlying the induction of learning and memory impairments remains a challenge. Recent investigations have shown that the activation of group I mGluRs (mGluR1 and mGluR5) in cultured hippocampal neurons by application of (S)-3,5-Dihydroxyphenylglycine (DHPG) causes the regulated internalization of N-methyl-D-aspartate receptors (NMDARs), which subsequently activates protein kinase D1 (PKD1). Through phosphorylating the C-terminals of the NMDAR GluN2 subunits, PKD1 down-regulates the activity of remaining (non-internalized) surface NMDARs. The knockdown of PKD1 does not affect the DHPG-induced inhibition of AMPA receptor-mediated miniature excitatory post-synaptic currents (mEPSCs) but prevents the DHPG-induced inhibition of NMDAR-mediated mEPSCs in vitro. Thus, we investigated the in vivo effects of bilateral infusions of DHPG into the hippocampal CA1 area of rats in the Morris water maze (MWM) and the novel object discrimination (NOD) tests. Methods A total of 300 adult male Sprague Dawley rats (250–280 g) were used for behavioral tests. One hundred ninety four were used in MWM test and the other 106 rats in the NOD test. Following one week of habituation to the vivarium, rats were bilaterally implanted under deep anesthesia with cannulas aimed at the CA1 area of the hippocampus (CA1 coordinates in mm from Bregma: AP -3.14; lateral +/-2; DV -3.0). Through implanted cannulas artificial cerebrospinal fluid (ACSF), the group1 mGluR antagonist 6-Methyl-2-(phenylethynyl)pyridine (MPEP), the dynamin-dependent internalization inhibitor Dynasore, or the PKD1 inhibitor CID755673 were infused into the bilateral hippocampal CA1 areas (2 μL per side, over 5 min). The effects of these infusions and the effects of PKD1 knockdown were examined in MWM or NOD test. Results DHPG infusion increased the latency to reach the platform in the MWM test and reduced the preference for the novel object in the NOD task. We found that the DHPG effects were dose-dependent and could be maintained for up to 2 days. Notably, these effects could be prevented by pre-infusion of the group1 mGluR antagonist MPEP, the dynamin-dependent internalization inhibitor Dynasore, the PKD1 inhibitor CID755673, or by PKD1 knockdown in the hippocampal CA1 area. Conclusion Altogether, these findings provide direct evidence that PKD1-mediated signaling may play a critical role in the induction of learning and memory impairments by DHPG infusion into the hippocampal CA1 area.
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Affiliation(s)
- Wei Wang
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
- BenQ Affiliated Hospital and Neurological Institute, Nanjing Medical University, Nanjing, People’s Republic of China
| | - Florian Duclot
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Bradley R. Groveman
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Nicole Carrier
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Haifa Qiao
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Xiao-Qian Fang
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
- Department of Biomedical Sciences, University of Texas Rio Grande Valley School of Medicine, Edinburg, Texas, United States of America
| | - Hui Wang
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
| | - Wenkuan Xin
- College of Pharmaceutical Sciences, Southwest University, Chongqing, People’s Republic of China
| | - Xing-Hong Jiang
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, People’s Republic of China
| | - Michael W. Salter
- Program in Neuroscience and Mental Health, Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Xin-Sheng Ding
- Department of Neurology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, People’s Republic of China
- BenQ Affiliated Hospital and Neurological Institute, Nanjing Medical University, Nanjing, People’s Republic of China
- * E-mail: (XD); (MK); (XMY)
| | - Mohamed Kabbaj
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
- * E-mail: (XD); (MK); (XMY)
| | - Xian-Min Yu
- BenQ Affiliated Hospital and Neurological Institute, Nanjing Medical University, Nanjing, People’s Republic of China
- Department of Biomedical Sciences, Florida State University, Tallahassee, Florida, United States of America
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, People’s Republic of China
- * E-mail: (XD); (MK); (XMY)
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GPR30 activation improves memory and facilitates DHPG-induced LTD in the hippocampal CA3 of middle-aged mice. Neurobiol Learn Mem 2018; 149:10-19. [DOI: 10.1016/j.nlm.2018.02.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Revised: 01/05/2018] [Accepted: 02/04/2018] [Indexed: 11/30/2022]
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24
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Ledonne A, Mango D, Latagliata EC, Chiacchierini G, Nobili A, Nisticò R, D'Amelio M, Puglisi-Allegra S, Mercuri NB. Neuregulin 1/ErbB signalling modulates hippocampal mGluRI-dependent LTD and object recognition memory. Pharmacol Res 2018; 130:12-24. [PMID: 29427771 DOI: 10.1016/j.phrs.2018.02.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Revised: 01/19/2018] [Accepted: 02/02/2018] [Indexed: 01/05/2023]
Abstract
The neurotrophic factors neuregulins (NRGs) and their receptors, ErbB tyrosine kinases, regulate neurotransmission, synaptic plasticity and cognitive functions and their alterations have been associated to different neuropsychiatric disorders. Group 1 metabotropic glutamate receptors (mGluRI)-dependent mechanisms are also altered in animal models of neuropsychiatric diseases, especially mGluRI-induced glutamatergic long-term depression (mGluRI-LTD), a form of synaptic plasticity critically involved in learning and memory. Despite this evidence, a potential link between NRGs/ErbB signalling and mGluRI-LTD has never been considered. Here, we aimed to test the hypothesis that NRGs/ErbB signalling regulates mGluRI functions in the hippocampus, thus controlling CA1 pyramidal neurons excitability and synaptic plasticity as well as mGluRI-dependent behaviors. We investigated the functional interaction between NRG1/ErbB signalling and mGluRI in hippocampal CA1 pyramidal neurons, by analyzing the effect of a pharmacological modulation of NRG1/ErbB signalling on the excitation of pyramidal neurons and on the LTD at CA3-CA1 synapses induced by an mGluRI agonist. Furthermore, we verified the involvement of ErbB signalling in mGluRI-dependent learning processes, by evaluating the consequence of an intrahippocampal in vivo injection of a pan-ErbB inhibitor in the object recognition test in mice, a learning task dependent on hippocampal mGluRI. We found that NRG1 potentiates mGluRI-dependent functions on pyramidal neurons excitability and synaptic plasticity at CA3-CA1 synapses. Further, endogenous ErbB signalling per se regulates, through mGluRI, neuronal excitability and LTD in CA1 pyramidal neurons, since ErbB inhibition reduces mGluRI-induced neuronal excitation and mGluRI-LTD. In vivo intrahippocampal injection of the ErbB inhibitor, PD158780, impairs mGluRI-LTD at CA3-CA1 synapses and affects the exploratory behavior in the object recognition test. Thus, our results identify a key role for NRG1/ErbB signalling in the regulation of hippocampal mGluRI-dependent synaptic and cognitive functions, whose alteration might contribute to the pathogenesis of different brain diseases.
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Affiliation(s)
- Ada Ledonne
- Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy.
| | - Dalila Mango
- Pharmacology of Synaptic Disease Lab, European Brain Research Institute, Rome, Italy
| | | | - Giulia Chiacchierini
- Department of Psychology and "Daniel Bovet" Center, University "La Sapienza", Rome, Italy
| | - Annalisa Nobili
- Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy; Department of Medicine, University Campus-Biomedico, Rome, Italy
| | - Robert Nisticò
- Pharmacology of Synaptic Disease Lab, European Brain Research Institute, Rome, Italy; Department of Biology, University of Rome "Tor Vergata", Rome, Italy
| | - Marcello D'Amelio
- Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy; Department of Medicine, University Campus-Biomedico, Rome, Italy
| | - Stefano Puglisi-Allegra
- Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy; Department of Psychology and "Daniel Bovet" Center, University "La Sapienza", Rome, Italy
| | - Nicola Biagio Mercuri
- Department of Experimental Neuroscience, Santa Lucia Foundation, Rome, Italy; Department of Systems Medicine, University of Rome "Tor Vergata", Rome, Italy
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Disturbance of Metabotropic Glutamate Receptor-Mediated Long-Term Depression (mGlu-LTD) of Excitatory Synaptic Transmission in the Rat Hippocampus After Prenatal Immune Challenge. Neurochem Res 2018; 44:609-616. [DOI: 10.1007/s11064-018-2476-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 12/28/2017] [Accepted: 01/15/2018] [Indexed: 12/31/2022]
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26
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Recording Field Potentials and Synaptic Plasticity From Freely Behaving Rodents. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2018. [DOI: 10.1016/b978-0-12-812028-6.00001-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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27
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Item-Place Encoding Through Hippocampal Long-Term Depression. HANDBOOK OF OBJECT NOVELTY RECOGNITION 2018. [DOI: 10.1016/b978-0-12-812012-5.00019-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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28
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Manahan-Vaughan D. Special Considerations When Using Mice for In Vivo Electrophysiology and Long-Term Studies of Hippocampal Synaptic Plasticity During Behavior. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2018. [DOI: 10.1016/b978-0-12-812028-6.00003-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Long Term Depression in Rat Hippocampus and the Effect of Ethanol during Fetal Life. Brain Sci 2017; 7:brainsci7120157. [PMID: 29182556 PMCID: PMC5742760 DOI: 10.3390/brainsci7120157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 11/20/2017] [Accepted: 11/27/2017] [Indexed: 12/11/2022] Open
Abstract
Alcohol (ethanol) disturbs cognitive functions including learning and memory in humans, non-human primates, and laboratory animals such as rodents. As studied in animals, cellular mechanisms for learning and memory include bidirectional synaptic plasticity, long-term potentiation (LTP), and long-term depression (LTD), primarily in the hippocampus. Most of the research in the field of alcohol has analyzed the effects of ethanol on LTP; however, with recent advances in the understanding of the physiological role of LTD in learning and memory, some authors have examined the effects of ethanol exposure on this particular signal. In the present review, I will focus on hippocampal LTD recorded in rodents and the effects of fetal alcohol exposure on this signal. A synthesis of the findings indicates that prenatal ethanol exposure disturbs LTD concurrently with LTP in offspring and that both glutamatergic and γ-aminobutyric acid (GABA) neurotransmissions are altered and contribute to LTD disturbances. Although the ultimate mode of action of ethanol on these two transmitter systems is not yet clear, novel suggestions have recently appeared in the literature.
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Wilkerson JR, Albanesi JP, Huber KM. Roles for Arc in metabotropic glutamate receptor-dependent LTD and synapse elimination: Implications in health and disease. Semin Cell Dev Biol 2017; 77:51-62. [PMID: 28969983 DOI: 10.1016/j.semcdb.2017.09.035] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/21/2017] [Accepted: 09/26/2017] [Indexed: 10/18/2022]
Abstract
The Arc gene is robustly transcribed in specific neural ensembles in response to experience-driven activity. Upon induction, Arc mRNA is transported to dendrites, where it can be rapidly and locally translated by activation of metabotropic glutamate receptors (mGluR1/5). mGluR-induced dendritic synthesis of Arc is implicated in weakening or elimination of excitatory synapses by triggering endocytosis of postsynaptic AMPARs in both hippocampal CA1 and cerebellar Purkinje neurons. Importantly, CA1 neurons with experience-induced Arc mRNA are susceptible, or primed for mGluR-induced long-term synaptic depression (mGluR-LTD). Here we review mechanisms and function of Arc in mGluR-LTD and synapse elimination and propose roles for these forms of plasticity in Arc-dependent formation of sparse neural representations of learned experience. We also discuss accumulating evidence linking dysregulation of Arc and mGluR-LTD in human cognitive disorders such as intellectual disability, autism and Alzheimer's disease.
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Affiliation(s)
- Julia R Wilkerson
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Joseph P Albanesi
- Departments of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Kimberly M Huber
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
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31
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Rodríguez-Durán LF, Martínez-Moreno A, Escobar ML. Bidirectional modulation of taste aversion extinction by insular cortex LTP and LTD. Neurobiol Learn Mem 2017; 142:85-90. [DOI: 10.1016/j.nlm.2016.12.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/16/2016] [Accepted: 12/23/2016] [Indexed: 01/21/2023]
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32
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Jansen S, Gottschling C, Faissner A, Manahan-Vaughan D. Intrinsic cellular and molecular properties of in vivo hippocampal synaptic plasticity are altered in the absence of key synaptic matrix molecules. Hippocampus 2017; 27:920-933. [DOI: 10.1002/hipo.22742] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 04/19/2017] [Accepted: 05/12/2017] [Indexed: 12/30/2022]
Affiliation(s)
- Stephan Jansen
- Department of Neurophysiology, Medical Faculty; Ruhr University Bochum; Bochum Germany
| | - Christine Gottschling
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology; Ruhr University Bochum; Bochum Germany
| | - Andreas Faissner
- Department of Cell Morphology and Molecular Neurobiology, Faculty of Biology and Biotechnology; Ruhr University Bochum; Bochum Germany
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33
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Stone TW, Darlington LG, Forrest CM. Dependence receptor involvement in subtilisin-induced long-term depression and in long-term potentiation. Neuroscience 2016; 336:49-62. [PMID: 27590265 DOI: 10.1016/j.neuroscience.2016.08.043] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/09/2016] [Accepted: 08/24/2016] [Indexed: 12/19/2022]
Abstract
The serine protease subtilisin induces a form of long-term depression (LTD) which is accompanied by a reduced expression of the axo-dendritic guidance molecule Unco-ordinated-5C (Unc-5C). One objective of the present work was to determine whether a loss of Unc-5C function contributed to subtilisin-induced LTD by using Unc-5C antibodies in combination with the pore-forming agents Triton X-100 (0.005%) or streptolysin O in rat hippocampal slices. In addition we have assessed the effect of subtilisin on the related dependence receptor Deleted in Colorectal Cancer (DCC) and used antibodies to this protein for functional studies. Field excitatory postsynaptic potentials (fEPSPs) were analyzed in rat hippocampal slices and protein extracts were used for Western blotting. Subtilisin produced a greater loss of DCC than of Unc-5C, but the antibodies had no effect on resting excitability or fEPSPs and did not modify subtilisin-induced LTD. However, antibodies to DCC but not Unc-5C did reduce the amplitude of theta-burst long-term potentiation (LTP). In addition, two inhibitors of endocytosis - dynasore and tat-gluR2(3Y) - were tested and, although the former compound had no effect on neurophysiological responses, tat-gluR2(3Y) did reduce the amplitude of subtilisin-induced LTD without affecting the expression of DCC or Unc-5C but with some loss of PostSynaptic Density Protein-95. The results support the view that the dependence receptor DCC may be involved in LTP and suggest that the endocytotic removal of a membrane protein or proteins may contribute to subtilisin-induced LTD, although it appears that neither Unc-5C nor DCC are involved in this process.
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Affiliation(s)
- Trevor W Stone
- Institute of Neurosciences and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK.
| | | | - Caroline M Forrest
- Institute of Neurosciences and Psychology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, UK
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34
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Jones OD. Do group I metabotropic glutamate receptors mediate LTD? Neurobiol Learn Mem 2016; 138:85-97. [PMID: 27545442 DOI: 10.1016/j.nlm.2016.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/01/2016] [Accepted: 08/17/2016] [Indexed: 01/31/2023]
Abstract
Synapses undergo significant structural and functional reorganization in response to varying patterns of stimulation. These forms of plasticity are considered fundamental to cognition and neuronal homeostasis. An increasing number of reports highlight the importance of activity-dependent synaptic strengthening (long term potentiation: LTP) for learning. However, the functional significance of activity-dependent weakening of synapses (long term depression: LTD) remains relatively poorly understood. One form of synaptic weakening, induced by group I metabotropic glutamate receptors (mGluRs), has received significant attention from a mechanistic point of view and because of its augmentation in a murine model of Fragile X Syndrome. Yet, studies of this form of plasticity often yield confusing, contradictory results. These conflicting findings are likely attributable to the bulk stimulation and recording techniques often used to study synaptic plasticity (typically involving evoked extracellular recordings, which represent the summed activity of many synapses). Such studies inherently blur the identity of the synapses undergoing change, thus giving the illusion that synapses per se are being modified when in fact this may only be true of a specific subset of synapses. Indeed, studies employing minimal synaptic activation paint a fundamentally different picture of what is commonly called "mGluR-LTD". Here, I review the evidence in favour of group I mGluRs as mediators of various forms of synaptic downregulation and attempt to explain discrepancies in the literature. I argue that, while multiple forms of synaptic weakening may be triggered by these receptors, the canonical form of group I mGluR-mediated depression, mGluR-LTD, is in fact not a depression of basal synaptic responses. Rather, it is a reversal of established LTP and thus a form of depotentiation. Far from being arbitrary, this distinction has significant implications for the role of group I mGluRs in cognition, both in the healthy brain and in pathological conditions. Further, the differential actions of group I mGluRs at naïve and potentiated synapses suggest these receptors signal in a state-dependent manner to regulate various stages of the learning process.
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Affiliation(s)
- Owen D Jones
- Department of Psychology, Brain Health Research Centre & Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
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35
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Metabotropic glutamate receptor, mGlu5, regulates hippocampal synaptic plasticity and is required for tetanisation-triggered changes in theta and gamma oscillations. Neuropharmacology 2016; 115:20-29. [PMID: 27395786 DOI: 10.1016/j.neuropharm.2016.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/04/2023]
Abstract
Hippocampal synaptic plasticity and learning are regulated by metabotropic glutamate receptors (mGlu) and particularly by mGlu5. In the hippocampus, synaptic plasticity is tightly linked to neuronal network oscillations in theta (5-10 Hz) and gamma (∼30-100 Hz) frequency ranges, and specific changes in theta and gamma spectral power can predict for the success of patterned afferent stimulation in inducing robust long-term potentiation (LTP). In this study, we hypothesized that activation of mGlu5 mediates tetanisation-driven changes in network oscillations and thereby determines the longevity of LTP. To explore this, we applied high-frequency stimulation (HFS) to the perforant path input to the dentate gyrus (DG), in the presence of the negative allosteric modulator, 2-methyl-6-(phenylethynyl)pyridine (MPEP), or the positive allosteric modulator (S)-(4-fluorophenyl)-[3-(3-(3-(4-fluorophenyl)-[1,2,4]oxadiazol-5-yl)-piperidin-1-yl)]methanone (ADX47273). In freely behaving rats, administration of MPEP resulted in a significant impairment, whereas treatment with ADX47273 led to a significant enhancement, of LTP (>24 h) compared to vehicle-treated controls. Allosteric potentiation of mGlu5 also resulted in a significantly greater increase of the spectral power of theta and gamma oscillations within the period of 300 s after HFS, as compared to MPEP-treated animals or controls. Our findings show that the regulation of hippocampal LTP by mGlu5 is associated with modulation of network oscillatory activity in the period shortly after LTP induction. Taken together, these data demonstrate that changes in the spectral contents of local field activity that occur in response to patterned afferent stimulation require activation of mGlu5 and may be instrumental for the successful expression of persistent LTP. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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36
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Hagena H, Manahan-Vaughan D. The serotonergic 5-HT4 receptor: A unique modulator of hippocampal synaptic information processing and cognition. Neurobiol Learn Mem 2016; 138:145-153. [PMID: 27317942 DOI: 10.1016/j.nlm.2016.06.014] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 06/06/2016] [Accepted: 06/14/2016] [Indexed: 01/10/2023]
Abstract
Serotonin (5-hydroxytryptamine, 5-HT) contributes in multifarious ways to the regulation of brain function, spanning key aspects such as the sleep-wake cycle, appetite, mood and mental health. The 5-HT receptors comprise seven receptor families (5-HT1-7) that are further subdivided into 14 receptor subtypes. The role of the 5-HT receptor in the modulation of neuronal excitability has been well documented. Recently, however, it has become apparent that the 5-HT4 receptor may contribute significantly to cognition and regulates less ostensible aspects of brain function: it engages in metaplastic regulation of synaptic responsiveness in key brain structures such as the hippocampus, thereby specifically promoting persistent forms of synaptic plasticity, and influences the direction of change in synaptic strength in selected hippocampal subfields. This highly specific neuromodulatory control by the 5-HT4 receptor may in turn explain the reported role for this receptor in hippocampus-dependent cognition. In this review article, we describe the role of the 5-HT4 receptor in hippocampal function, and describe how this receptor plays a unique and highly specialised role in synaptic information storage and cognition.
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Affiliation(s)
- Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Germany
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37
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Buschler A, Manahan-Vaughan D. Metabotropic glutamate receptor, mGlu5, mediates enhancements of hippocampal long-term potentiation after environmental enrichment in young and old mice. Neuropharmacology 2016; 115:42-50. [PMID: 27267685 DOI: 10.1016/j.neuropharm.2016.06.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 12/24/2022]
Abstract
The metabotropic glutamate (mGlu) receptor, mGlu5, is of particular relevance for hippocampal function. It is critically required for the expression of long-term potentiation (LTP) and long-term depression (LTD), regulates neuronal oscillations, maintains the stability of place fields and is required for hippocampus-dependent memory. MGlu5-dysfunctions are associated with profound cognitive deficits in humans, and mGlu5 has been targeted as a putative cognitive enhancer. Cognitive enhancement, by means of environmental enrichment (EE) in rodents, results in improved hippocampal synaptic plasticity and memory. Here, we explored whether mGlu5 contributes to these enhancements. MGlu5-antagonism dose-dependently impaired the early phase of LTP (>4 h) in the CA1 region of young(3-4 month old) mice. Late-LTP (>24 h) was also impaired. LTP (>24 h) elicited in old (10-14 month old) mice displayed reduced sensitivity to mGlu5 antagonism. Short-term potentiation (STP, < 2 h) that was elicited by weaker afferent stimulation was unaffected by mGlu5-antagonism in both age-groups. EE significantly amplified STP (<2 h) in old and young animals, but did not increase the duration of synaptic potentiation, or promote induction of LTP. The improvement in STP was prevented by mGlu5-antagonism, in both young and old animals. These results indicate that modifications of the synapse that underlie improvements of LTP by EE require the contribution of mGlu5. Strikingly, although LTP in old mice does not critically depend on mGlu5, improvements in synaptic potentiation resulting from EE are mGlu5-dependent in old mice. Regarded in light of the known role for mGlu5 in hippocampal function and pathophysiology, these data suggest that mGlu5 regulation of synaptic information storage is pivotal to optimal hippocampal function. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Arne Buschler
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany
| | - Denise Manahan-Vaughan
- Ruhr University Bochum, Medical Faculty, Department of Neurophysiology, Bochum, Germany.
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38
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Sanderson TM, Hogg EL, Collingridge GL, Corrêa SAL. Hippocampal metabotropic glutamate receptor long-term depression in health and disease: focus on mitogen-activated protein kinase pathways. J Neurochem 2016; 139 Suppl 2:200-214. [PMID: 26923875 DOI: 10.1111/jnc.13592] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 02/16/2016] [Accepted: 02/21/2016] [Indexed: 12/16/2022]
Abstract
Group I metabotropic glutamate receptor (mGluR) dependent long-term depression (LTD) is a major form of synaptic plasticity underlying learning and memory. The molecular mechanisms involved in mGluR-LTD have been investigated intensively for the last two decades. In this 60th anniversary special issue article, we review the recent advances in determining the mechanisms that regulate the induction, transduction and expression of mGluR-LTD in the hippocampus, with a focus on the mitogen-activated protein kinase (MAPK) pathways. In particular we discuss the requirement of p38 MAPK and extracellular signal-regulated kinase 1/2 (ERK 1/2) activation. The recent advances in understanding the signaling cascades regulating mGluR-LTD are then related to the cognitive impairments observed in neurological disorders, such as fragile X syndrome and Alzheimer's disease. mGluR-LTD is a form of synaptic plasticity that impacts on memory formation. In the hippocampus mitogen-activated protein kinases (MAPKs) have been found to be important in mGluR-LTD. In this 60th anniversary special issue article, we review the independent and complementary roles of two classes of MAPK, p38 and ERK1/2 and link this to the aberrant mGluR-LTD that has an important role in diseases. This article is part of the 60th Anniversary special issue.
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Affiliation(s)
- Thomas M Sanderson
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK
| | - Ellen L Hogg
- Bradford School of Pharmacy, Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Graham L Collingridge
- Centre for Synaptic Plasticity, School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, UK. .,Department of Physiology, University of Toronto, Toronto, Ontario, Canada. .,Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.
| | - Sonia A L Corrêa
- Bradford School of Pharmacy, Faculty of Life Sciences, University of Bradford, Bradford, UK.
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39
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Dietz B, Manahan-Vaughan D. Hippocampal long-term depression is facilitated by the acquisition and updating of memory of spatial auditory content and requires mGlu5 activation. Neuropharmacology 2016; 115:30-41. [PMID: 27055771 DOI: 10.1016/j.neuropharm.2016.02.026] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Revised: 01/22/2016] [Accepted: 02/22/2016] [Indexed: 12/21/2022]
Abstract
Long-term potentiation (LTP) and long-term depression (LTD) are key cellular processes that support memory formation. Whereas increases of synaptic strength by means of LTP may support the creation of a spatial memory 'engram', LTD appears to play an important role in refining and optimising experience-dependent encoding. A differentiation in the role of hippocampal subfields is apparent. For example, LTD in the dentate gyrus (DG) is enabled by novel learning about large visuospatial features, whereas in area CA1, it is enabled by learning about discrete aspects of spatial content, whereby, both discrete visuospatial and olfactospatial cues trigger LTD in CA1. Here, we explored to what extent local audiospatial cues facilitate information encoding in the form of LTD in these subfields. Coupling of low frequency afferent stimulation (LFS) with discretely localised, novel auditory tones in the sonic hearing, or ultrasonic range, facilitated short-term depression (STD) into LTD (>24 h) in CA1, but not DG. Re-exposure to the now familiar audiospatial configuration ca. 1 week later failed to enhance STD. Reconfiguration of the same audiospatial cues resulted anew in LTD when ultrasound, but not non-ultrasound cues were used. LTD facilitation that was triggered by novel exposure to spatially arranged tones, or to spatial reconfiguration of the same tones were both prevented by an antagonism of the metabotropic glutamate receptor, mGlu5. These data indicate that, if behaviourally salient enough, the hippocampus can use audiospatial cues to facilitate LTD that contributes to the encoding and updating of spatial representations. Effects are subfield-specific, and require mGlu5 activation, as is the case for visuospatial information processing. These data reinforce the likelihood that LTD supports the encoding of spatial features, and that this occurs in a qualitative and subfield-specific manner. They also support that mGlu5 is essential for synaptic encoding of spatial experience. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Birte Dietz
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, 44780, Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, 44780, Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, 44780, Bochum, Germany.
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Twarkowski H, Hagena H, Manahan-Vaughan D. The 5-hydroxytryptamine4 receptor enables differentiation of informational content and encoding in the hippocampus. Hippocampus 2016; 26:875-91. [PMID: 26800645 PMCID: PMC5067691 DOI: 10.1002/hipo.22569] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 01/15/2016] [Accepted: 01/20/2016] [Indexed: 11/10/2022]
Abstract
Long‐term synaptic plasticity, represented by long‐term depression (LTD) and long‐term potentiation (LTP) comprise cellular processes that enable memory. Neuromodulators such as serotonin regulate hippocampal function, and the 5‐HT4‐receptor contributes to processes underlying cognition. It was previously shown that in the CA1‐region, 5‐HT4‐receptors regulate the frequency‐response relationship of synaptic plasticity: patterned afferent stimulation that has no effect on synaptic strength (i.e., a θm‐frequency), will result in LTP or LTD, when given in the presence of a 5‐HT4‐agonist, or antagonist, respectively. Here, we show that in the dentate gyrus (DG) and CA3 regions of freely behaving rats, pharmacological manipulations of 5‐HT4‐receptors do not influence responses generated at θm‐frequencies, but activation of 5‐HT4‐receptors prevents persistent LTD in mossy fiber (mf)‐CA3, or perforant path‐DG synapses. Furthermore, the regulation by 5‐HT4‐receptors of LTP is subfield‐specific: 5‐HT4‐receptor‐activation prevents mf‐CA3‐LTP, but does not strongly affect DG‐potentiation. These data suggest that 5‐HT4‐receptor activation prioritises information encoding by means of LTP in the DG and CA1 regions, and suppresses persistent information storage in mf‐CA3 synapses. Thus, 5‐HT4‐receptors serve to shape information storage across the hippocampal circuitry and specify the nature of experience‐dependent encoding. © 2016 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Hannah Twarkowski
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
| | - Hardy Hagena
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Bochum, Germany.,International Graduate School of Neuroscience, Ruhr University Bochum, Bochum, Germany
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Aarse J, Herlitze S, Manahan-Vaughan D. The requirement of BDNF for hippocampal synaptic plasticity is experience-dependent. Hippocampus 2016; 26:739-51. [PMID: 26662461 PMCID: PMC5066736 DOI: 10.1002/hipo.22555] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2015] [Indexed: 12/05/2022]
Abstract
Brain‐derived neurotrophic factor (BDNF) supports neuronal survival, growth, and differentiation and has been implicated in forms of hippocampus‐dependent learning. In vitro, a specific role in hippocampal synaptic plasticity has been described, although not all experience‐dependent forms of synaptic plasticity critically depend on BDNF. Synaptic plasticity is likely to enable long‐term synaptic information storage and memory, and the induction of persistent (>24 h) forms, such as long‐term potentiation (LTP) and long‐term depression (LTD) is tightly associated with learning specific aspects of a spatial representation. Whether BDNF is required for persistent (>24 h) forms of LTP and LTD, and how it contributes to synaptic plasticity in the freely behaving rodent has never been explored. We examined LTP, LTD, and related forms of learning in the CA1 region of freely dependent mice that have a partial knockdown of BDNF (BDNF+/−). We show that whereas early‐LTD (<90min) requires BDNF, short‐term depression (<45 min) does not. Furthermore, BDNF is required for LTP that is induced by mild, but not strong short afferent stimulation protocols. Object‐place learning triggers LTD in the CA1 region of mice. We observed that object‐place memory was impaired and the object‐place exploration failed to induce LTD in BDNF+/− mice. Furthermore, spatial reference memory, that is believed to be enabled by LTP, was also impaired. Taken together, these data indicate that BDNF is required for specific, but not all, forms of hippocampal‐dependent information storage and memory. Thus, very robust forms of synaptic plasticity may circumvent the need for BDNF, rather it may play a specific role in the optimization of weaker forms of plasticity. The finding that both learning‐facilitated LTD and spatial reference memory are both impaired in BDNF+/− mice, suggests moreover, that it is critically required for the physiological encoding of hippocampus‐dependent memory. © 2015 The Authors Hippocampus Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Janna Aarse
- Department of Neurophysiology, Medical Faculty.,International Graduate School of Neuroscience
| | - Stefan Herlitze
- Faculty of Biology and Biotechnology, Department of Zoology and Neurobiology Ruhr University, Bochum, 44780 Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty.,International Graduate School of Neuroscience
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Sarantis K, Tsiamaki E, Kouvaros S, Papatheodoropoulos C, Angelatou F. Adenosine A₂A receptors permit mGluR5-evoked tyrosine phosphorylation of NR2B (Tyr1472) in rat hippocampus: a possible key mechanism in NMDA receptor modulation. J Neurochem 2015; 135:714-26. [PMID: 26303340 DOI: 10.1111/jnc.13291] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 07/23/2015] [Accepted: 08/07/2015] [Indexed: 12/30/2022]
Abstract
A great body of evidence points toward a functional interaction between metabotropic glutamate 5 receptors (mGluR5) and NMDA receptors (NMDAR) that enhances synaptic plasticity and cognition. However, the molecular mechanism underlying this interaction remains unclear. Here, we show that co-activation of mGluR5 and NMDAR in hippocampal slices synergistically leads to a robust phosphorylation of NR2B (Tyr1472), which is Src kinase dependent and is enabled by endogenous adenosine acting on A2A receptors. As it is well known, NR2B (Tyr1472) phosphorylation anchors NR2B-containing NMDARs to the surface of post-synaptic membranes, preventing their internalization. This is supported by our electrophysiological experiments showing that co-activation of mGluR5 and NMDARs robustly enhances NMDAR-dependent neuronal excitability recorded in CA1 hippocampal region, which temporally coincides with the robust increase in NR2B (Tyr1472) phosphorylation, depends on Src kinases and is also permitted by A2A receptors. Thus, we strongly suggest that NR2B (Tyr1472) phosphorylation constitutes, at least to some extent, the molecular mechanism underlying the mGluR5-mediated enhancement of NMDAR-dependent responses, which is modulated by A2A receptors. A better understanding of the molecular basis of mGluR5/NMDAR interaction would elucidate their role in synaptic plasticity processes as well as in pathological conditions. We propose the following molecular mechanism by which metabotropic Glutamate Receptor 5 (mGluR5) potentiate ionotropic Glutamate N-Methyl-D-Aspartate Receptor (NMDAR) responses in rat hippocampus. Co-activation of mGLUR5/NMDAR activates Src kinases, leading to NR2B(Tyr1472) phosphorylation, which anchors NR2B-containing NMDAR to the plasma membrane, thus inducing a robust increase in the NMDA-dependent excitability. Interestingly, adenosine A2A receptors license the mGluR5-induced NR2B(Tyr1472) phosphorylation.
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Affiliation(s)
| | - Eirini Tsiamaki
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | - Stylianos Kouvaros
- Physiology Department, Medical School, University of Patras, Patras, Greece
| | | | - Fevronia Angelatou
- Physiology Department, Medical School, University of Patras, Patras, Greece
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43
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mGlu5 acts as a switch for opposing forms of synaptic plasticity at mossy fiber-CA3 and commissural associational-CA3 synapses. J Neurosci 2015; 35:4999-5006. [PMID: 25810529 DOI: 10.1523/jneurosci.3417-14.2015] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Within the hippocampus, different kinds of spatial experience determine the direction of change of synaptic weights. Synaptic plasticity resulting from such experience may enable memory encoding. The CA3 region is very striking in this regard: due to the distinct molecular properties of the mossy fiber (MF) and associational-commissural (AC) synapses, it is believed that they enable working memory and pattern completion. The question arises, however, as to how information reaching these synapses results in differentiated encoding. Given its crucial role in enabling persistent synaptic plasticity in other hippocampal subfields, we speculated that the metabotropic glutamate receptor mGlu5 may regulate information encoding at MF and AC synapses. Here, we show that antagonism of mGlu5 inhibits LTP, but not LTD at MF synapses of freely behaving adult rats. Conversely, mGlu5 antagonism prevents LTD but not LTP at AC-CA3 synapses. This suggests that, under conditions in which mGlu5 is activated, LTP may be preferentially induced at MF synapses, whereas LTD is favored at AC synapses. To assess this possibility, we applied 50 Hz stimulation that should generate postsynaptic activity that corresponds to θm, the activation threshold that lies between LTP and LTD. MGlu5 activation had no effect on AC responses but potentiated MF synapses. These data suggest that mGlu5 serves as a switch that alters signal-to-noise ratios during information encoding in the CA3 region. This mechanism supports highly tuned and differentiated information storage in CA3 synapses.
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Abstract
Resolving how our brains encode information requires an understanding of the cellular processes taking place during memory formation. Since the 1970s, considerable effort has focused on determining the properties and mechanisms underlying long-term potentiation (LTP) at glutamatergic synapses and how these processes influence initiation of new memories. However, accumulating evidence suggests that long-term depression (LTD) of synaptic strength, particularly at glutamatergic synapses, is a bona fide learning and memory mechanism in the mammalian brain. The known range of mechanisms capable of inducing LTD has been extended to those including NMDAR-independent forms, neuromodulator-dependent LTD, synaptic depression following stress, and non-synaptically induced forms. The examples of LTD observed at the hippocampal CA1 synapse to date demonstrate features consistent with LTP, including homo- and heterosynaptic expression, extended duration beyond induction (several hours to weeks), and association with encoding of distinct types of memories. Canonical mechanisms through which synapses undergo LTD include activation of phosphatases, initiation of protein synthesis, and dynamic regulation of presynaptic glutamate release and/or postsynaptic glutamate receptor endocytosis. Here, we will discuss the pre- and postsynaptic changes underlying LTD, recent advances in the identification and characterization of novel mechanisms underlying LTD, and how engagement of these processes constitutes a cellular analog for the genesis of specific types of memories.
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Affiliation(s)
- Steven A Connor
- Brain Research Centre and Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yu Tian Wang
- Brain Research Centre and Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
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Novkovic T, Shchyglo O, Gold R, Manahan-Vaughan D. Hippocampal function is compromised in an animal model of multiple sclerosis. Neuroscience 2015; 309:100-12. [PMID: 25795599 DOI: 10.1016/j.neuroscience.2015.03.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 02/11/2015] [Accepted: 03/04/2015] [Indexed: 11/30/2022]
Abstract
Multiple sclerosis (MS) is a progressive inflammatory autoimmune disease that is characterized by demyelination and axonal damage in the nervous system. One obvious consequence is a cumulative loss of muscle control. However, cognitive dysfunction affects roughly half of MS sufferers, sometimes already early in the disease course. Although long-term (remote) memory is typically unaffected, the ability to form new declarative memories becomes compromised. A major structure for the encoding of new declarative memories is the hippocampus. Encoding is believed to be mediated by synaptic plasticity in the form of long-term potentiation (LTP) and long-term depression (LTD) of synaptic strength. Here, in an animal model of MS we explored whether disease symptoms are accompanied by a loss of functional neuronal integrity, synaptic plasticity, or hippocampus-dependent learning ability. In mice that developed MOG35-55-induced experimental autoimmune encephalomyelitis (EAE), passive properties of CA1 pyramidal neurons were unaffected, although the ability to fire action potentials became reduced in the late phase of EAE. LTP remained normal in the early phase of MOG35-55-induced EAE. However, in the late phase, LTP was impaired and LTP-related spatial memory was impaired. In contrast, LTD and hippocampus-dependent object recognition memory were unaffected. These data suggest that in an animal model of MS hippocampal function becomes compromised as the disease progresses.
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Affiliation(s)
- T Novkovic
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Germany
| | - O Shchyglo
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Germany
| | - R Gold
- International Graduate School of Neuroscience, Ruhr University Bochum, Germany; Neurological University Clinic, St. Josef Hospital, Medical Faculty, Ruhr University Bochum, Germany
| | - D Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Germany; International Graduate School of Neuroscience, Ruhr University Bochum, Germany.
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André MAE, Güntürkün O, Manahan-Vaughan D. The metabotropic glutamate receptor, mGlu5, is required for extinction learning that occurs in the absence of a context change. Hippocampus 2015; 25:149-58. [PMID: 25160592 PMCID: PMC4322473 DOI: 10.1002/hipo.22359] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2014] [Indexed: 11/21/2022]
Abstract
The metabotropic glutamate (mGlu) receptors and, in particular, mGlu5 are crucially involved in multiple forms of synaptic plasticity that are believed to underlie explicit memory. MGlu5 is also required for information transfer through neuronal oscillations and for spatial memory. Furthermore, mGlu5 is involved in extinction of implicit forms of learning. This places this receptor in a unique position with regard to information encoding. Here, we explored the role of this receptor in context-dependent extinction learning under constant, or changed, contextual conditions. Animals were trained over 3 days to take a left turn under 25% reward probability in a T-maze with a distinct floor pattern (Context A). On Day 4, they experienced either a floor pattern change (Context B) or the same floor pattern (Context A) in the absence of reward. After acquisition of the task, the animals were returned to the maze once more on Day 5 (Context A, no reward). Treatment with the mGlu5 antagonist, 2-methyl-6-(phenylethynyl) pyridine, before maze exposure on Day 4 completely inhibited extinction learning in the AAA paradigm but had no effect in the ABA paradigm. A subsequent return to the original context (A, on Day 5) revealed successful extinction in the AAA paradigm, but impairment of extinction in the ABA paradigm. These data support that although extinction learning in a new context is unaffected by mGlu5 antagonism, extinction of the consolidated context is impaired. This suggests that mGlu5 is intrinsically involved in enabling learning that once-relevant information is no longer valid.
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Affiliation(s)
- Marion Agnes Emma André
- International Graduate School for Neuroscience, Ruhr University BochumBochum, Germany
- Department of Biopsychology, Faculty of Psychology, Ruhr University BochumBochum, Germany
| | - Onur Güntürkün
- International Graduate School for Neuroscience, Ruhr University BochumBochum, Germany
- Department of Biopsychology, Faculty of Psychology, Ruhr University BochumBochum, Germany
| | - Denise Manahan-Vaughan
- International Graduate School for Neuroscience, Ruhr University BochumBochum, Germany
- Department of Neurophysiology, Medical Faculty, Ruhr University BochumBochum, Germany
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47
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The effect of the mGlu5 negative allosteric modulator MTEP and NMDA receptor partial agonist D-cycloserine on Pavlovian conditioned fear. Int J Neuropsychopharmacol 2014; 17:1521-32. [PMID: 24674862 DOI: 10.1017/s1461145714000303] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
The metabotropic glutamate receptor 5 (mGlu5) and N-methyl-D-aspartate (NMDA) receptor are critical for processes underlying synaptic plasticity, such as long-term potentiation. mGlu5 signaling increases neuronal excitability and potentiates NMDA receptor currents in the amygdala and the hippocampus. The present study examined the involvement of mGlu5 in the acquisition and consolidation of conditioned fear to a tone and context in mice, and explored the functional relationship between mGlu5 and NMDA receptors in this regard. Experiment 1 showed that systemic administration of the mGlu5 negative allosteric modulator 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]pyridine (MTEP) prior to conditioning significantly attenuated cue-elicited freezing during fear conditioning, which suggests that mGlu5 is necessary for the formation of a tone-shock association. This effect was dose-related (Experiment 2) and not due to any effects of MTEP on shock sensitivity or state-dependency (Experiment 3). Post-conditioning injection of MTEP had no effects (Experiment 4). Although post-conditioning injection of the NMDA receptor partial agonist D-cycloserine (DCS) alone facilitated consolidation of conditioned fear (Experiment 6), it was not able to rescue the acquisition deficit caused by MTEP (Experiment 5). Taken together, these findings indicate a crucial role for mGlu5 signaling in acquisition and NMDA receptor signaling in consolidation of conditioned fear.
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48
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Novkovic T, Mittmann T, Manahan-Vaughan D. BDNF contributes to the facilitation of hippocampal synaptic plasticity and learning enabled by environmental enrichment. Hippocampus 2014; 25:1-15. [PMID: 25112659 DOI: 10.1002/hipo.22342] [Citation(s) in RCA: 126] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/05/2014] [Indexed: 12/12/2022]
Abstract
Sensory, motor, and cognitive stimuli, resulting from interactions with the environment, play a key role in optimizing and modifying the neuronal circuitry required for normal brain function. An experimental animal model for this phenomenon comprises environmental enrichment (EE) in rodents. EE causes profound changes in neuronal and signaling levels of excitation and plasticity throughout the entire central nervous system and the hippocampus is particularly affected. The mechanisms underlying these changes are not yet fully understood. As brain-derived neurotrophic factor (BDNF) supports hippocampal long-term potentiation (LTP), we explored whether it participates in the facilitation of synaptic plasticity and hippocampus-dependent learning that occurs following EE. In the absence of EE, LTP elicited by high-frequency stimulation was equivalent in wildtype mice and heterozygous BDNF(+/-) siblings. LTP elicited by theta-burst stimulation in BDNF(+/-) mice was less than in wildtypes. Long-term depression (LTD) was also impaired. EE for three weeks, beginning after weaning, improved hippocampal LTP in both wildtype and transgenic animals, with LTP in transgenics achieving levels seen in wildtypes in the absence of EE. Object recognition memory was evident in wildtypes 24 h and 7 days after initial object exposure. EE improved memory performance in wildtypes 24 h but not 7 days after initial exposure. BDNF(+/-) mice in the absence of EE showed impaired memory 7 days after initial object exposure that was restored by EE. Western blotting revealed increased levels of BDNF, but not proBDNF, among both EE cohorts. These data support that BDNF plays an intrinsic role in improvements of synaptic plasticity and cognition that occur in EE.
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Affiliation(s)
- Tanja Novkovic
- Medical Faculty, Department of Neurophysiology, Ruhr University Bochum, 44780, Bochum, Germany; International Graduate School of Neuroscience, 44780 Bochum, Germany, 44780, Bochum, Germany
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Di Prisco GV, Huang W, Buffington SA, Hsu CC, Bonnen PE, Placzek AN, Sidrauski C, Krnjević K, Kaufman RJ, Walter P, Costa-Mattioli M. Translational control of mGluR-dependent long-term depression and object-place learning by eIF2α. Nat Neurosci 2014; 17:1073-82. [PMID: 24974795 PMCID: PMC4340591 DOI: 10.1038/nn.3754] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 05/30/2014] [Indexed: 02/06/2023]
Abstract
At hippocampal synapses, activation of group I metabotropic glutamate receptors (mGluRs) induces long-term depression (LTD), which requires new protein synthesis. However, the underlying mechanism remains elusive. Here we describe the translational program that underlies mGluR-LTD and identify the translation factor eIF2α as its master effector. Genetically reducing eIF2α phosphorylation, or specifically blocking the translation controlled by eIF2α phosphorylation, prevented mGluR-LTD and the internalization of surface AMPA receptors (AMPARs). Conversely, direct phosphorylation of eIF2α, bypassing mGluR activation, triggered a sustained LTD and removal of surface AMPARs. Combining polysome profiling and RNA sequencing, we identified the mRNAs translationally upregulated during mGluR-LTD. Translation of one of these mRNAs, oligophrenin-1, mediates the LTD induced by eIF2α phosphorylation. Mice deficient in phospho-eIF2α-mediated translation are impaired in object-place learning, a behavioral task that induces hippocampal mGluR-LTD in vivo. Our findings identify a new model of mGluR-LTD, which promises to be of value in the treatment of mGluR-LTD-linked cognitive disorders.
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Affiliation(s)
- Gonzalo Viana Di Prisco
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas, USA. [3]
| | - Wei Huang
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas, USA. [3]
| | - Shelly A Buffington
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas, USA. [3]
| | - Chih-Chun Hsu
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas, USA
| | - Penelope E Bonnen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Andon N Placzek
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Present address: Division of Basic Medical Sciences, Mercer University School of Medicine, Macon, Georgia, USA
| | - Carmela Sidrauski
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | - Krešimir Krnjević
- Department of Physiology, McGill University, Montreal, Quebec, Canada
| | - Randal J Kaufman
- Center for Neuroscience, Aging, and Stem Cell Research, Sanford-Burnham Medical Research Institute, La Jolla, California, USA
| | - Peter Walter
- Department of Biochemistry and Biophysics, Howard Hughes Medical Institute, University of California San Francisco, San Francisco, California, USA
| | - Mauro Costa-Mattioli
- 1] Department of Neuroscience, Baylor College of Medicine, Houston, Texas, USA. [2] Memory and Brain Research Center, Baylor College of Medicine, Houston, Texas, USA
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Goh JJ, Manahan-Vaughan D. Role of inhibitory autophosphorylation of calcium/calmodulin-dependent kinase II (αCAMKII) in persistent (>24 h) hippocampal LTP and in LTD facilitated by novel object-place learning and recognition in mice. Behav Brain Res 2014; 285:79-88. [PMID: 24480420 DOI: 10.1016/j.bbr.2014.01.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 01/07/2014] [Accepted: 01/17/2014] [Indexed: 11/16/2022]
Abstract
Experience-dependent synaptic plasticity is widely expressed in the mammalian brain and is believed to underlie memory formation. Persistent forms of synaptic plasticity in the hippocampus, such as long-term potentiation (LTP) and long-term depression (LTD) are particularly of interest, as evidence is accumulating that they are expressed as a consequence of, or at the very least in association with, hippocampus-dependent novel learning events. Learning-facilitated plasticity describes the property of hippocampal synapses to express persistent synaptic plasticity when novel spatial learning is combined with afferent stimulation that is subthreshold for induction of changes in synaptic strength. In mice it occurs following novel object recognition and novel object-place recognition. Calmodulin-dependent kinase II (CAMKII) is strongly expressed in synapses and has been shown to be required for hippocampal LTP in vitro and for spatial learning in the water maze. Here, we show that in mice that undergo persistent inhibitory autophosphorylation of αCAMKII, object-place learning is intact. Furthermore, these animals demonstrate a higher threshold for induction of persistent (>24 h) hippocampal LTP in the hippocampal CA1 region during unrestrained behaviour. The transgenic mice also express short-term depression in response to afferent stimulation frequencies that are ineffective in controls. Furthermore, they express stronger LTD in response to novel learning of spatial configurations compared to controls. These findings support that modulation of αCAMKII activity via autophosphorylation at the Thr305/306 site comprises a key mechanism for the maintenance of synaptic plasticity within a dynamic range. They also indicate that a functional differentiation occurs in the way spatial information is encoded: whereas LTP is likely to be critically involved in the encoding of space per se, LTD appears to play a special role in the encoding of the content or features of space.
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Affiliation(s)
- Jinzhong Jeremy Goh
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Universitaetsstr. 150, MA 4/150, 44780 Bochum, Germany
| | - Denise Manahan-Vaughan
- Department of Neurophysiology, Medical Faculty, Ruhr University Bochum, Universitaetsstr. 150, MA 4/150, 44780 Bochum, Germany.
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