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Pintori N, Piva A, Mottarlini F, Díaz FC, Maggi C, Caffino L, Fumagalli F, Chiamulera C. Brief exposure to enriched environment rapidly shapes the glutamate synapses in the rat brain: A metaplastic fingerprint. Eur J Neurosci 2024; 59:982-995. [PMID: 38378276 DOI: 10.1111/ejn.16279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 09/22/2023] [Accepted: 01/27/2024] [Indexed: 02/22/2024]
Abstract
Environmental enrichment (EE) has been shown to produce beneficial effects in addiction disorders; however, due to its configurational complexity, the underlying mechanisms are not yet fully elucidated. Recent evidence suggests that EE, acting as a metaplastic agent, may affect glutamatergic mechanisms underlying appetitive memory and, in turn, modulate reward-seeking behaviours: here, we have investigated such a possibility following a brief EE exposure. Adult male Sprague-Dawley rats were exposed to EE for 22 h and the expression of critical elements of the glutamate synapse was measured 2 h after the end of EE in the medial prefrontal cortex (mPFC), nucleus accumbens (NAc) and hippocampus (Hipp) brain areas, which are critical for reward and memory. We focused our investigation on the expression of NMDA and AMPA receptor subunits, their scaffolding proteins SAP102 and SAP97, vesicular and membrane glutamate transporters vGluT1 and GLT-1, and critical structural components such as proteins involved in morphology and function of glutamatergic synapses, PSD95 and Arc/Arg3.1. Our findings demonstrate that a brief EE exposure induces metaplastic changes in glutamatergic mPFC, NAc and Hipp. Such changes are area-specific and involve postsynaptic NMDA/AMPA receptor subunit composition, as well as changes in the expression of their main scaffolding proteins, thus influencing the retention of such receptors at synaptic sites. Our data indicate that brief EE exposure is sufficient to dynamically modulate the glutamatergic synapses in mPFC-NAc-Hipp circuits, which may modulate rewarding and memory processes.
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Affiliation(s)
- Nicholas Pintori
- Section of Pharmacology, Department of Diagnostic & Public Health, University of Verona, Verona, Italy
- Current Affiliation: Department of Biomedical Sciences, University of Cagliari, Cittadella Universitaria di Monserrato, Cagliari, Italy
| | - Alessandro Piva
- Section of Pharmacology, Department of Diagnostic & Public Health, University of Verona, Verona, Italy
| | - Francesca Mottarlini
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', University of Milan, Milan, Italy
| | - Fernando Castillo Díaz
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', University of Milan, Milan, Italy
| | - Coralie Maggi
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', University of Milan, Milan, Italy
| | - Lucia Caffino
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', University of Milan, Milan, Italy
| | - Fabio Fumagalli
- Department of Pharmacological and Biomolecular Sciences 'Rodolfo Paoletti', University of Milan, Milan, Italy
| | - Cristiano Chiamulera
- Section of Pharmacology, Department of Diagnostic & Public Health, University of Verona, Verona, Italy
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2
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Tortella L, Santini I, Lozano N, Kostarelos K, Cellot G, Ballerini L. Graphene Oxide Nanosheets Hamper Glutamate Mediated Excitotoxicity and Protect Neuronal Survival In An In vitro Stroke Model. Chemistry 2023; 29:e202301762. [PMID: 37706581 DOI: 10.1002/chem.202301762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 09/06/2023] [Accepted: 09/13/2023] [Indexed: 09/15/2023]
Abstract
Small graphene oxide (s-GO) nanosheets reversibly downregulate central nervous system (CNS) excitatory synapses, with potential developments as future therapeutic tools to treat neuro-disorders characterized by altered glutamatergic transmission. Excitotoxicity, namely cell death triggered by exceeding ambient glutamate fueling over-activation of excitatory synapses, is a pathogenic mechanism shared by several neural diseases, from ischemic stroke to neurodegenerative disorders. In this work, CNS cultures were exposed to oxygen-glucose deprivation (OGD) to mimic ischemic stroke in vitro, and it is show that the delivery of s-GO following OGD, during the endogenous build-up of secondary damage and excitotoxicity, improved neuronal survival. In a different paradigm, excitotoxicity cell damage was reproduced through exogenous glutamate application, and s-GO co-treatment protected neuronal integrity, potentially by directly downregulating the synaptic over-activation brought about by exogenous glutamate. This proof-of-concept study suggests that s-GO may find novel applications in therapeutic developments for treating excitotoxicity-driven neural cell death.
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Affiliation(s)
- Lorenza Tortella
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, 34136, Trieste, Italy
| | - Irene Santini
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, 34136, Trieste, Italy
| | - Neus Lozano
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
| | - Kostas Kostarelos
- Catalan Institute of Nanoscience and Nanotechnology (ICN2), CSIC and BIST, Campus UAB, Bellaterra, 08193, Barcelona, Spain
- Nanomedicine Lab, and Faculty of Biology, Medicine & Health, The National Graphene Institute, University of Manchester, Manchester, M13 9PL, United Kingdom
| | - Giada Cellot
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, 34136, Trieste, Italy
| | - Laura Ballerini
- Neuroscience Area, International School for Advanced Studies (SISSA/ISAS), Via Bonomea 265, 34136, Trieste, Italy
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Anchesi I, Schepici G, Chiricosta L, Gugliandolo A, Salamone S, Caprioglio D, Pollastro F, Mazzon E. Δ 8-THC Induces Up-Regulation of Glutamatergic Pathway Genes in Differentiated SH-SY5Y: A Transcriptomic Study. Int J Mol Sci 2023; 24:ijms24119486. [PMID: 37298437 DOI: 10.3390/ijms24119486] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/18/2023] [Accepted: 05/28/2023] [Indexed: 06/12/2023] Open
Abstract
Cannabinoids, natural or synthetic, have antidepressant, anxiolytic, anticonvulsant, and anti-psychotic properties. Cannabidiol (CBD) and delta-9-tetrahydrocannabinol (Δ9-THC) are the most studied cannabinoids, but recently, attention has turned towards minor cannabinoids. Delta-8-tetrahydrocannabinol (Δ8-THC), an isomer of Δ9-THC, is a compound for which, to date, there is no evidence of its role in the modulation of synaptic pathways. The aim of our work was to evaluate the effects of Δ8-THC on differentiated SH-SY5Y human neuroblastoma cells. Using next generation sequencing (NGS), we investigated whether Δ8-THC could modify the transcriptomic profile of genes involved in synapse functions. Our results showed that Δ8-THC upregulates the expression of genes involved in the glutamatergic pathway and inhibits gene expression at cholinergic synapses. Conversely, Δ8-THC did not modify the transcriptomic profile of genes involved in the GABAergic and dopaminergic pathways.
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Affiliation(s)
- Ivan Anchesi
- IRCCS Centro Neurolesi "Bonino-Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124 Messina, Italy
| | - Giovanni Schepici
- IRCCS Centro Neurolesi "Bonino-Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124 Messina, Italy
| | - Luigi Chiricosta
- IRCCS Centro Neurolesi "Bonino-Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124 Messina, Italy
| | - Agnese Gugliandolo
- IRCCS Centro Neurolesi "Bonino-Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124 Messina, Italy
| | - Stefano Salamone
- Department of Pharmaceutical Sciences, University of Eastern Piedmont, Largo Donegani 2, 28100 Novara, Italy
- PlantaChem S.r.l.s., Via Amico Canobio 4/6, 28100 Novara, Italy
| | - Diego Caprioglio
- Department of Pharmaceutical Sciences, University of Eastern Piedmont, Largo Donegani 2, 28100 Novara, Italy
- PlantaChem S.r.l.s., Via Amico Canobio 4/6, 28100 Novara, Italy
| | - Federica Pollastro
- Department of Pharmaceutical Sciences, University of Eastern Piedmont, Largo Donegani 2, 28100 Novara, Italy
- PlantaChem S.r.l.s., Via Amico Canobio 4/6, 28100 Novara, Italy
| | - Emanuela Mazzon
- IRCCS Centro Neurolesi "Bonino-Pulejo", Via Provinciale Palermo, Contrada Casazza, 98124 Messina, Italy
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Ye L, Xu Y, Hu P, Wang L, Yang J, Yuan F, Wang Y, Zhang C, Tian D, Chen Q. Development and Verification of Glutamatergic Synapse-Associated Prognosis Signature for Lower-Grade Gliomas. Front Mol Neurosci 2021; 14:720899. [PMID: 34776862 PMCID: PMC8581158 DOI: 10.3389/fnmol.2021.720899] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 09/27/2021] [Indexed: 11/23/2022] Open
Abstract
Background: Lower-grade glioma (LGG) is the most common histology identified in gliomas, a heterogeneous tumor that may develop into high-grade malignant glioma that seriously shortens patient survival time. Recent studies reported that glutamatergic synapses might play an essential role in the progress of gliomas. However, the role of glutamatergic synapse-related biomarkers in LGG has not been systemically researched yet. Methods: The mRNA expression data of glioma and normal brain tissue were obtained from The Cancer Genome Atlas database and Genotype-Tissue Expression, respectively, and the Chinese Glioma Genome Atlas database was used as a validation set. Difference analysis was performed to evaluate the expression pattern of glutamatergic synapse-related genes (GSRGs) in LGG. The least absolute shrinkage and selection operator (LASSO) Cox regression was applied to construct the glutamatergic synapse-related risk signature (GSRS), and the risk score of each LGG sample was calculated based on the coefficients and expression value of selected GSRGs. Univariate and multivariate Cox regression analyses were used to investigate the prognostic value of risk score. Immunity profile and single-sample gene set enrichment analysis (ssGSEA) were performed to explore the association between risk score and the characters of tumor microenvironment in LGG. Gene set variation analysis (GSVA) was performed to investigate the potential pathways related to GSRS. The HPA database and real-time PCR were used to identify the expression of hub genes identified in GSRS. Results: A total of 22 genes of 39 GSRGs were found differentially expressed among normal and LGG samples. Through the LASSO algorithm, 14-genes GSRS constructed were associated with the prognosis and clinicopathological features of patients with LGG. Furthermore, the risk score level was significantly positively correlated with the infiltrating level of immunosuppressive cells, including M2 macrophages and regulatory T cells. GSVA identified a series of cancer-related pathways related to GSRS, such as P13K-AKT and P53 pathways. Moreover, ATAD1, NLGN2, OXTR, and TNR, hub genes identified in GSRS, were considered as potential prognostic biomarkers in LGG. Conclusion: A 14-genes GSRS was constructed and verified in this study. We provided a novel insight into the role of GSRS in LGG through a series of bioinformatics methods.
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Affiliation(s)
- Liguo Ye
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yang Xu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ping Hu
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Long Wang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Ji'an Yang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Fan'en Yuan
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Yixuan Wang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Chunyu Zhang
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Daofeng Tian
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
| | - Qianxue Chen
- Department of Neurosurgery, Renmin Hospital of Wuhan University, Wuhan, China
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Cordella F, Sanchini C, Rosito M, Ferrucci L, Pediconi N, Cortese B, Guerrieri F, Pascucci GR, Antonangeli F, Peruzzi G, Giubettini M, Basilico B, Pagani F, Grimaldi A, D’Alessandro G, Limatola C, Ragozzino D, Di Angelantonio S. Antibiotics Treatment Modulates Microglia-Synapses Interaction. Cells 2021; 10:cells10102648. [PMID: 34685628 PMCID: PMC8534187 DOI: 10.3390/cells10102648] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Revised: 09/30/2021] [Accepted: 10/01/2021] [Indexed: 12/12/2022] Open
Abstract
‘Dysbiosis’ of the adult gut microbiota, in response to challenges such as infection, altered diet, stress, and antibiotics treatment has been recently linked to pathological alteration of brain function and behavior. Moreover, gut microbiota composition constantly controls microglia maturation, as revealed by morphological observations and gene expression analysis. However, it is unclear whether microglia functional properties and crosstalk with neurons, known to shape and modulate synaptic development and function, are influenced by the gut microbiota. Here, we investigated how antibiotic-mediated alteration of the gut microbiota influences microglial and neuronal functions in adult mice hippocampus. Hippocampal microglia from adult mice treated with oral antibiotics exhibited increased microglia density, altered basal patrolling activity, and impaired process rearrangement in response to damage. Patch clamp recordings at CA3-CA1 synapses revealed that antibiotics treatment alters neuronal functions, reducing spontaneous postsynaptic glutamatergic currents and decreasing synaptic connectivity, without reducing dendritic spines density. Antibiotics treatment was unable to modulate synaptic function in CX3CR1-deficient mice, pointing to an involvement of microglia–neuron crosstalk through the CX3CL1/CX3CR1 axis in the effect of dysbiosis on neuronal functions. Together, our findings show that antibiotic alteration of gut microbiota impairs synaptic efficacy, suggesting that CX3CL1/CX3CR1 signaling supporting microglia is a major player in in the gut–brain axis, and in particular in the gut microbiota-to-neuron communication pathway.
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Affiliation(s)
- Federica Cordella
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Caterina Sanchini
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Maria Rosito
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- Correspondence: (M.R.); (S.D.A.)
| | - Laura Ferrucci
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
| | - Natalia Pediconi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Barbara Cortese
- National Research Council-Nanotechnology Institute, 00185 Rome, Italy;
| | - Francesca Guerrieri
- Cancer Research Center of Lyon (CRCL), UMR Inserm U1052/CNRS 5286, 69373 Lyon, France; (F.G.); (G.R.P.)
| | - Giuseppe Rubens Pascucci
- Cancer Research Center of Lyon (CRCL), UMR Inserm U1052/CNRS 5286, 69373 Lyon, France; (F.G.); (G.R.P.)
| | - Fabrizio Antonangeli
- Department of Molecular Medicine, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
| | - Giovanna Peruzzi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | | | - Bernadette Basilico
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
| | - Francesca Pagani
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- National Research Council-Nanotechnology Institute, 00185 Rome, Italy;
| | - Alfonso Grimaldi
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
| | - Giuseppina D’Alessandro
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
| | - Cristina Limatola
- Department of Physiology and Pharmacology, Laboratory Affiliated to Istituto Pasteur Italia, Sapienza University, 00185 Rome, Italy;
- IRCCS Neuromed, Via Atinese 18, 86077 Pozzilli, Italy
| | - Davide Ragozzino
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Santa Lucia Foundation, European Center for Brain Research, 00143 Rome, Italy
| | - Silvia Di Angelantonio
- Department of Physiology and Pharmacology “V. Erspamer”, Sapienza University, 00185 Rome, Italy; (F.C.); (C.S.); (L.F.); (B.B.); (G.D.); (D.R.)
- Center for Life Nano- & Neuro-Science, Fondazione Istituto Italiano di Tecnologia (IIT), 00161 Rome, Italy; (N.P.); (G.P.); (F.P.); (A.G.)
- Correspondence: (M.R.); (S.D.A.)
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6
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Polenghi A, Nieus T, Guazzi S, Gorostiza P, Petrini EM, Barberis A. Kainate Receptor Activation Shapes Short-Term Synaptic Plasticity by Controlling Receptor Lateral Mobility at Glutamatergic Synapses. Cell Rep 2021; 31:107735. [PMID: 32521260 PMCID: PMC7296349 DOI: 10.1016/j.celrep.2020.107735] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 04/26/2020] [Accepted: 05/14/2020] [Indexed: 01/24/2023] Open
Abstract
Kainate receptors (KARs) mediate postsynaptic currents with a key impact on neuronal excitability. However, the molecular determinants controlling KAR postsynaptic localization and stabilization are poorly understood. Here, we exploit optogenetic and single-particle tracking approaches to study the role of KAR conformational states induced by glutamate binding on KAR lateral mobility at synapses. We report that following glutamate binding, KARs are readily and reversibly trapped at glutamatergic synapses through increased interaction with the β-catenin/N-cadherin complex. We demonstrate that such activation-dependent synaptic immobilization of KARs is crucial for the modulation of short-term plasticity of glutamatergic synapses. Thus, the present study unveils the crosstalk between conformational states and lateral mobility of KARs, a mechanism regulating glutamatergic signaling, particularly in conditions of sustained synaptic activity. Anchoring of KARs at glutamatergic synapses depends on receptor-glutamate binding KARs activation/desensitization promotes receptors trapping at glutamatergic synapses N-cadherins mediate the KAR activation/desensitization-dependent anchoring at synapses Synaptic trapping of desensitized KARs affects short-term synaptic plasticity
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Affiliation(s)
- Alice Polenghi
- Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Thierry Nieus
- Department of Biomedical and Clinical Sciences "L. Sacco," University of Milan, Milan, Italy
| | - Stefania Guazzi
- Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Pau Gorostiza
- Catalan Institution for Research and Advanced Studies (ICREA), 08010 Barcelona, Spain; Institute for Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, 08028 Barcelona, Spain; Network Biomedical Research Center in Bioengineering, Biomaterials and Nanotechnology (CIBER-BBN), 50018 Zaragoza, Spain
| | - Enrica Maria Petrini
- Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Andrea Barberis
- Synaptic Plasticity of Inhibitory Networks, Fondazione Istituto Italiano di Tecnologia, 16163 Genova, Italy.
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7
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Lo AC, Rajan N, Gastaldo D, Telley L, Hilal ML, Buzzi A, Simonato M, Achsel T, Bagni C. Absence of RNA-binding protein FXR2P prevents prolonged phase of kainate-induced seizures. EMBO Rep 2021; 22:e51404. [PMID: 33779029 PMCID: PMC8024897 DOI: 10.15252/embr.202051404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 01/26/2021] [Accepted: 01/29/2021] [Indexed: 12/26/2022] Open
Abstract
Status epilepticus (SE) is a condition in which seizures are not self-terminating and thereby pose a serious threat to the patient's life. The molecular mechanisms underlying SE are likely heterogeneous and not well understood. Here, we reveal a role for the RNA-binding protein Fragile X-Related Protein 2 (FXR2P) in SE. Fxr2 KO mice display reduced sensitivity specifically to kainic acid-induced SE. Immunoprecipitation of FXR2P coupled to next-generation sequencing of associated mRNAs shows that FXR2P targets are enriched in genes that encode glutamatergic post-synaptic components. Of note, the FXR2P target transcriptome has a significant overlap with epilepsy and SE risk genes. In addition, Fxr2 KO mice fail to show sustained ERK1/2 phosphorylation induced by KA and present reduced burst activity in the hippocampus. Taken together, our findings show that the absence of FXR2P decreases the expression of glutamatergic proteins, and this decrease might prevent self-sustained seizures.
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Affiliation(s)
- Adrian C Lo
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Nicholas Rajan
- Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Denise Gastaldo
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Ludovic Telley
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Muna L Hilal
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Andrea Buzzi
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy
| | - Michele Simonato
- Department of Neuroscience and Rehabilitation, University of Ferrara, Ferrara, Italy.,Division of Neuroscience, IRCCS San Raffaele Hospital, Milan, Italy
| | - Tilmann Achsel
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland
| | - Claudia Bagni
- Department of Fundamental Neurosciences, University of Lausanne, Lausanne, Switzerland.,Department of Neurosciences and Leuven Brain Institute, KU Leuven, Leuven, Belgium.,Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy
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8
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Jones S. De-mobilisation of NMDA receptors in midbrain dopamine neurons: a quantum of reward? J Physiol 2021; 599:2777-2778. [PMID: 33769567 DOI: 10.1113/jp281559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 03/22/2021] [Indexed: 11/08/2022] Open
Affiliation(s)
- Susan Jones
- Department of Physiology, Development & Neuroscience, University of Cambridge, Cambridge, UK
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9
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Abstract
A comprehensive review of the body of genetic studies on schizophrenia seems even more daunting than the battle a psychiatrist wages daily in the office with her archenemy of a thousand faces. The following article reunites some genetic, epigenetic and environmental factors of schizophrenia from revered and vast studies in a chronological and progressive fashion. Twin studies set the basics of heritability and a particular study by Davis and Phelps considers the widely ignored influence of prenatal environment in the development of schizophrenia. Mostly ignited by linkage studies, candidate gene studies explore further by fine-mapping the hypothesized variants [mostly in the forms single nucleotide polymorphisms (SNPs) and less but with greater impact copy number variations (CNVs)] associated with the disease. Genome-wide association studies (GWAS) increase considerably the sample sizes and thus the validity of the results, while the next-generation sequencing (NGS) attain the highest yet unreplicated level of validity results.
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Affiliation(s)
- Simona Corina Trifu
- Department of Neurosciences, 'Carol Davila' University of Medicine and Pharmacy, 020021 Bucharest, Romania
| | - Bianca Kohn
- Department of Psychiatry, 'Prof. Dr. Alexandru Obregia' Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Andrei Vlasie
- Department of Psychiatry, 'Prof. Dr. Alexandru Obregia' Clinical Hospital of Psychiatry, 041914 Bucharest, Romania
| | - Bogdan-Eduard Patrichi
- Department of Psychiatry and Psychology, 'Carol Davila' University of Medicine and Pharmacy, 020021 Bucharest, Romania
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10
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Kesaf S, Khirug S, Dinh E, Saez Garcia M, Soni S, Orav E, Delpire E, Taira T, Lauri SE, Rivera C. The Kainate Receptor Subunit GluK2 Interacts With KCC2 to Promote Maturation of Dendritic Spines. Front Cell Neurosci 2020; 14:252. [PMID: 33005130 PMCID: PMC7479265 DOI: 10.3389/fncel.2020.00252] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/22/2020] [Indexed: 12/25/2022] Open
Abstract
Kainate receptors (KAR) play a crucial role in the plasticity and functional maturation of glutamatergic synapses. However, how they regulate structural plasticity of dendritic spines is not known. The GluK2 subunit was recently shown to coexist in a functional complex with the neuronal K-Cl cotransporter KCC2. Apart from having a crucial role in the maturation of GABAergic transmission, KCC2 has a morphogenic role in the maturation of dendritic spines. Here, we show that in vivo local inactivation of GluK2 expression in CA3 hippocampal neurons induces altered morphology of dendritic spines and reduction in mEPSC frequency. GluK2 deficiency also resulted in a strong change in the subcellular distribution of KCC2 as well as a smaller somatodendritic gradient in the reversal potential of GABAA. Strikingly, the aberrant morphology of dendritic spines in GluK2-deficient CA3 pyramidal neurons was restored by overexpression of KCC2. GluK2 silencing in hippocampal neurons significantly reduced the expression of 4.1N and functional form of the actin filament severing protein cofilin. Consistently, assessment of actin dynamics using fluorescence recovery after photobleaching (FRAP) of β-actin showed a significant increase in the stability of F-actin filaments in dendritic spines. In conclusion, our results demonstrate that GluK2-KCC2 interaction plays an important role in the structural maturation of dendritic spines. This also provides novel insights into the connection between KAR dysfunction, structural plasticity, and developmental disorders.
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Affiliation(s)
- Sebnem Kesaf
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Stanislav Khirug
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Emilie Dinh
- Developmental Biology Institute of Marseille, Marseille, France
| | - Marta Saez Garcia
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Shetal Soni
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland
| | - Ester Orav
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN, United States
| | - Tomi Taira
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Veterinary Biosciences, University of Helsinki, Helsinki, Finland
| | - Sari E Lauri
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Molecular and Integrative Biosciences Research Program, University of Helsinki, Helsinki, Finland
| | - Claudio Rivera
- HiLIFE Neuroscience Center, University of Helsinki, Helsinki, Finland.,Institut de Neurobiologie de la Méditerranée (INMED) UMR901, Marseille, France
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11
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Kessler JP, Salin P, Kerkerian-Le Goff L. Glutamate transporter 1-expressing glia in the rat substantia nigra-Morphometric analysis and relationships to synapses. Glia 2020; 68:2028-2039. [PMID: 32170887 DOI: 10.1002/glia.23823] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 11/12/2022]
Abstract
Glial cells have a major role in protecting neurons against various forms of stress. Especially, astrocytes mediate the bulk of glutamate clearance in the brain via specific membrane transporters (GLAST and GLT1), thereby preventing the occurrence of excitotoxic events. Although glutamate-mediated mechanisms are thought to contribute to nigral dopaminergic neuron degeneration in Parkinson's disease, detailed information on the organization of glia in the substantia nigra is still lacking. The present study was performed to provide quantitative information on the organization of astroglia and on the relationships between astrocytes and excitatory synapses in the rat substantia nigra. Using immunolabeling of GLT1 and confocal imaging, we found that the substantia nigra was filled with a dense meshwork of immunoreactive astrocyte processes. Stereological analysis performed on electron microscope images revealed that the density of immunoreactive astrocyte plasma membranes was substantial, close to 1 μm2 /μm3 , in the substantia nigra neuropil, both in the pars compacta and the pars reticulata. Excitatory synapses had on average two thirds of their perimeters free from glia, a disposition that may favor transmitter spillover. The density of glutamatergic synapses, as quantified on confocal images by the simultaneous detection of bassoon and of vesicular glutamate transporter 1 or 2, was very low (0.01 and 0.025 per μm3 in the reticulata and compacta subdivisions, respectively). Thus the ratio of GLT1-expressing glial membrane surface to glutamatergic synapses was very high (40-100 μm2 ), suggesting an efficient regulation of extracellular glutamate concentrations.
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Affiliation(s)
| | - Pascal Salin
- Aix Marseille University, CNRS, IBDM, Marseille, France
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12
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Abstract
UNLABELLED AMPA-type glutamate receptors are ligand-gated cation channels responsible for a majority of the fast excitatory synaptic transmission in the brain. Their behavior and calcium permeability depends critically on their subunit composition and the identity of associated auxiliary proteins. Calcium-permeable AMPA receptors (CP-AMPARs) contribute to various forms of synaptic plasticity, and their dysfunction underlies a number of serious neurological conditions. For CP-AMPARs, the prototypical transmembrane AMPAR regulatory protein stargazin, which acts as an auxiliary subunit, enhances receptor function by increasing single-channel conductance, slowing channel gating, increasing calcium permeability, and relieving the voltage-dependent block by endogenous intracellular polyamines. We find that, in contrast, GSG1L, a transmembrane auxiliary protein identified recently as being part of the AMPAR proteome, acts to reduce the weighted mean single-channel conductance and calcium permeability of recombinant CP-AMPARs, while increasing polyamine-dependent rectification. To examine the effects of GSG1L on native AMPARs, we manipulated its expression in cerebellar and hippocampal neurons. Transfection of GSG1L into mouse cultured cerebellar stellate cells that lack this protein increased the inward rectification of mEPSCs. Conversely, shRNA-mediated knockdown of endogenous GSG1L in rat cultured hippocampal pyramidal neurons led to an increase in mEPSC amplitude and in the underlying weighted mean single-channel conductance, revealing that GSG1L acts to suppress current flow through native CP-AMPARs. Thus, our data suggest that GSG1L extends the functional repertoire of AMPAR auxiliary subunits, which can act not only to enhance but also diminish current flow through their associated AMPARs. SIGNIFICANCE STATEMENT Calcium-permeable AMPA receptors (CP-AMPARs) are an important group of receptors for the neurotransmitter glutamate. These receptors contribute to various forms of synaptic plasticity, and alterations in their expression or regulation are also seen in a number of serious neurological conditions, including stroke, motor neuron disease, and cocaine addiction. Several groups of auxiliary transmembrane proteins have been described that enhance the function and cell-surface expression of AMPARs. We now report that the recently identified auxiliary protein GSG1L decreases weighted mean channel conductance and calcium permeability of CP-AMPARs while increasing polyamine-dependent rectification by diminishing outward current. Our experiments reveal that GSG1L is an auxiliary subunit that can markedly suppress CP-AMPAR function, in both recombinant systems and central neurons.
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13
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Maixner DW, Yan X, Hooks SB, Weng HR. AMPKα1 knockout enhances nociceptive behaviors and spinal glutamatergic synaptic activities via production of reactive oxygen species in the spinal dorsal horn. Neuroscience 2016; 326:158-169. [PMID: 27058143 DOI: 10.1016/j.neuroscience.2016.03.061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Revised: 03/25/2016] [Accepted: 03/28/2016] [Indexed: 12/15/2022]
Abstract
Emerging studies have shown that pharmacological activation of adenosine monophosphate-activated protein kinase (AMPK) produces potent analgesic effects in different animal pain models. Currently, the spinal molecular and synaptic mechanism by which AMPK regulates the pain signaling system remains unclear. To address this issue, we utilized the Cre-LoxP system to conditionally knockout the AMPKα1 gene in the nervous system of mice. We demonstrated that AMPKα1 is imperative for maintaining normal nociception, and mice deficient for AMPKα1 exhibit mechanical allodynia. This is concomitantly associated with increased glutamatergic synaptic activities in neurons located in the superficial spinal dorsal horn, which results from the increased glutamate release from presynaptic terminals and function of ligand-gated glutamate receptors at the postsynaptic neurons. Additionally, AMPKα1 knockout mice have increased activities of extracellular signal-regulated kinases (ERK) and p38 mitogen-activated protein kinases (p38), as well as elevated levels of interleukin-1β (IL-1β), reactive oxygen species (ROS), and heme oxygenase 1 (HO-1) in the spinal dorsal horn. Systemic administration of a non-specific ROS scavenger (phenyl-N-tert-butylnitrone, PBN) or a HO-1 activator (Cobalt protoporphyrin IX, CoPP) attenuated allodynia in AMPKα1 knockout mice. Bath-perfusion of the ROS scavenger or HO-1 activator effectively attenuated the increased ROS levels and glutamatergic synaptic activities in the spinal dorsal horn. Our findings suggest that ROS are the key down-stream signaling molecules mediating the behavioral hypersensitivity in AMPKα1 knockout mice. Thus, targeting AMPKα1 may represent an effective approach for the treatment of pathological pain conditions associated with neuroinflammation at the spinal dorsal horn.
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Affiliation(s)
- Dylan W Maixner
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia 30602, USA
| | - Xisheng Yan
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia 30602, USA.,Department of Cardiovascular Medicine, The Third Hospital of Wuhan, Wuhan 430074, Hubei Province, China.,Department of Endocrinology and Metabolism, Shanghai Tenth People's hospital, Tongji University School of Medicine, Shanghai 200072, China
| | - Shelley B Hooks
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia 30602, USA
| | - Han-Rong Weng
- Department of Pharmaceutical and Biomedical Sciences, The University of Georgia College of Pharmacy, Athens, Georgia 30602, USA
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14
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Villalba RM, Mathai A, Smith Y. Morphological changes of glutamatergic synapses in animal models of Parkinson's disease. Front Neuroanat 2015; 9:117. [PMID: 26441550 PMCID: PMC4585113 DOI: 10.3389/fnana.2015.00117] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/17/2015] [Indexed: 02/05/2023] Open
Abstract
The striatum and the subthalamic nucleus (STN) are the main entry doors for extrinsic inputs to reach the basal ganglia (BG) circuitry. The cerebral cortex, thalamus and brainstem are the key sources of glutamatergic inputs to these nuclei. There is anatomical, functional and neurochemical evidence that glutamatergic neurotransmission is altered in the striatum and STN of animal models of Parkinson’s disease (PD) and that these changes may contribute to aberrant network neuronal activity in the BG-thalamocortical circuitry. Postmortem studies of animal models and PD patients have revealed significant pathology of glutamatergic synapses, dendritic spines and microcircuits in the striatum of parkinsonians. More recent findings have also demonstrated a significant breakdown of the glutamatergic corticosubthalamic system in parkinsonian monkeys. In this review, we will discuss evidence for synaptic glutamatergic dysfunction and pathology of cortical and thalamic inputs to the striatum and STN in models of PD. The potential functional implication of these alterations on synaptic integration, processing and transmission of extrinsic information through the BG circuits will be considered. Finally, the significance of these pathological changes in the pathophysiology of motor and non-motor symptoms in PD will be examined.
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Affiliation(s)
- Rosa M Villalba
- Yerkes National Primate Research Center, Emory University Atlanta, GA, USA ; UDALL Center of Excellence for Parkinson's Disease, Emory University Atlanta, GA, USA
| | - Abraham Mathai
- Yerkes National Primate Research Center, Emory University Atlanta, GA, USA ; UDALL Center of Excellence for Parkinson's Disease, Emory University Atlanta, GA, USA
| | - Yoland Smith
- Yerkes National Primate Research Center, Emory University Atlanta, GA, USA ; UDALL Center of Excellence for Parkinson's Disease, Emory University Atlanta, GA, USA ; Department of Neurology, Emory University Atlanta, GA, USA
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15
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Corrales A, Vidal R, García S, Vidal V, Martínez P, García E, Flórez J, Sanchez-Barceló EJ, Martínez-Cué C, Rueda N. Chronic melatonin treatment rescues electrophysiological and neuromorphological deficits in a mouse model of Down syndrome. J Pineal Res 2014; 56:51-61. [PMID: 24147912 DOI: 10.1111/jpi.12097] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Accepted: 09/20/2013] [Indexed: 12/22/2022]
Abstract
The Ts65Dn mouse (TS), the most commonly used model of Down syndrome (DS), exhibits several key phenotypic characteristics of this condition. In particular, these animals present hypocellularity in different areas of their CNS due to impaired neurogenesis and have alterations in synaptic plasticity that compromise their cognitive performance. In addition, increases in oxidative stress during adulthood contribute to the age-related progression of cognitive and neuronal deterioration. We have previously demonstrated that chronic melatonin treatment improves learning and memory and reduces cholinergic neurodegeneration in TS mice. However, the molecular and physiological mechanisms that mediate these beneficial cognitive effects are not yet fully understood. In this study, we analyzed the effects of chronic melatonin treatment on different mechanisms that have been proposed to underlie the cognitive impairments observed in TS mice: reduced neurogenesis, altered synaptic plasticity, enhanced synaptic inhibition and oxidative damage. Chronic melatonin treatment rescued both impaired adult neurogenesis and the decreased density of hippocampal granule cells in trisomic mice. In addition, melatonin administration reduced synaptic inhibition in TS mice by increasing the density and/or activity of glutamatergic synapses in the hippocampus. These effects were accompanied by a full recovery of hippocampal LTP in trisomic animals. Finally, melatonin treatment decreased the levels of lipid peroxidation in the hippocampus of TS mice. These results indicate that the cognitive-enhancing effects of melatonin in adult TS mice could be mediated by the normalization of their electrophysiological and neuromorphological abnormalities and suggest that melatonin represents an effective treatment in retarding the progression of DS neuropathology.
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Affiliation(s)
- Andrea Corrales
- Department of Physiology and Pharmacology, School of Medicine, University of Cantabria, Santander, Spain
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16
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Abstract
L-glutamate is the primary neurotransmitter at excitatory synapses in the vertebrate CNS and at arthropod neuromuscular junctions (NMJs). However, the molecular mechanisms that trigger the recruitment of glutamate receptors at the onset of synaptogenesis and promote their stabilization at postsynaptic densities remain poorly understood. We have reported the discovery of a novel, evolutionary conserved molecule, Neto, essential for clustering of ionotropic glutamate receptors (iGluRs) at Drosophila NMJ. Neto is the first auxiliary subunit described in Drosophila and is the only non-channel subunit absolutely required for functional iGluRs. Here we review the role of Drosophila Neto in synapse assembly, its similarities with other Neto proteins and a new perspective on how glutamatergic synapses are physically assembled and stabilized.
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Affiliation(s)
- Young-Jun Kim
- 1Program in Cellular Regulation and Metabolism; NICHD; NIH; Bethesda, MD USA
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17
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Mulholland PJ, Becker HC, Woodward JJ, Chandler LJ. Small conductance calcium-activated potassium type 2 channels regulate alcohol-associated plasticity of glutamatergic synapses. Biol Psychiatry 2011; 69:625-32. [PMID: 21056409 PMCID: PMC3103782 DOI: 10.1016/j.biopsych.2010.09.025] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Revised: 09/08/2010] [Accepted: 09/10/2010] [Indexed: 01/22/2023]
Abstract
BACKGROUND Small conductance calcium-activated potassium type 2 channels (SK2) control excitability and contribute to plasticity by reducing excitatory postsynaptic potentials. Recent evidence suggests that SK2 channels form a calcium-dependent negative-feedback loop with synaptic N-methyl-D-aspartate (NMDA) receptors. Addiction to alcohol and other drugs of abuse induces plastic changes in glutamatergic synapses that include the targeting of NMDA receptors to synaptic sites; however, the role of SK2 channels in alcohol-associated homeostatic plasticity is unknown. METHODS Electrophysiology, Western blot, and behavioral analyses were used to quantify changes in hippocampal small conductance calcium-activated potassium (SK) channel function and expression using well-characterized in vitro and in vivo models of chronic alcohol exposure. RESULTS Chronic ethanol reduced apamin-sensitive SK currents in cornu ammonis 1 pyramidal neurons that were associated with a downregulation of surface SK2 channels. Blocking SK channels with apamin potentiated excitatory postsynaptic potentials in control but not ethanol-treated cornu ammonis 1 pyramidal neurons, suggesting that chronic ethanol disrupts the SK channel-NMDA receptor feedback loop. Alcohol reduced expression of SK2 channels and increased expression of NMDA receptors at synaptic sites in a mouse model. Positive modulation of SK function by 1-EBIO decreased alcohol withdrawal hyperexcitability and attenuated ethanol withdrawal neurotoxicity in hippocampus. The 1-EBIO also reduced seizure activity in mice undergoing withdrawal. CONCLUSIONS These results provide evidence that SK2 channels contribute to alcohol-associated adaptive plasticity of glutamatergic synapses and that positive modulation of SK channels reduces the severity of withdrawal-related hyperexcitability. Therefore, SK2 channels appear to be critical regulators of alcohol-associated plasticity and may be novel therapeutic targets for the treatment of addiction.
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Affiliation(s)
- Patrick J. Mulholland
- Department of Neurosciences, Medical University of South Carolina, 67 President Street, Charleston, SC, 29425
| | - Howard C. Becker
- Department of Psychiatry and VAMC, Medical University of South Carolina, 67 President Street, Charleston, SC, 29425
| | - John J. Woodward
- Department of Neurosciences, Medical University of South Carolina, 67 President Street, Charleston, SC, 29425
| | - L. Judson Chandler
- Department of Neurosciences, Medical University of South Carolina, 67 President Street, Charleston, SC, 29425
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18
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Wang H, Brozoski TJ, Ling L, Hughes LF, Caspary DM. Impact of sound exposure and aging on brain-derived neurotrophic factor and tyrosine kinase B receptors levels in dorsal cochlear nucleus 80 days following sound exposure. Neuroscience 2011; 172:453-9. [PMID: 21034795 PMCID: PMC3057525 DOI: 10.1016/j.neuroscience.2010.10.056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Revised: 10/18/2010] [Accepted: 10/19/2010] [Indexed: 11/22/2022]
Abstract
Recent studies suggested that acute sound exposure resulting in a temporary threshold shift in young adult animals within a series of maladaptive plasticity changes in central auditory structures. Brain-derived neurotrophic factor (BDNF), a member of the neurotrophin family, is involved in post-trauma peripheral hair cell and spiral ganglion cell survival and has been shown to modulate synaptic strength in cochlear nucleus following sound exposure. The present study evaluated levels of BDNF and its receptor (tyrosine kinase B, [TrkB]) in the dorsal cochlear nucleus (DCN) following a unilateral moderate sound exposure in young (7-8 months) and aged (28-29 months) Fischer Brown Norway (FBN) rats. Eighty days post-exposure, auditory brainstem response (ABR) thresholds for young exposed rats approached control values while aged exposed rats showed residual permanent threshold shifts (PTS) relative to aged controls. BDNF protein levels were significantly up-regulated by 9% in young exposed fusiform cells ipsilateral to the exposure. BDNF levels in aged sound-exposed fusiform cells increased 31% ipsilateral to the exposure. Protein levels of the BDNF receptor, TrkB, were also significantly increased in aged but not in young sound-exposed DCN fusiform cells. The present findings suggest a relationship between the up-regulation of BDNF/TrkB and the increase in spontaneous and driven activity previously observed for aged and sound-exposed fusiform cells. This might be due to a selective maladaptive compensatory down-regulation of glycinergic inhibition in DCN fusiform cells.
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MESH Headings
- Acoustic Stimulation/adverse effects
- Acoustic Stimulation/methods
- Aging/metabolism
- Animals
- Brain-Derived Neurotrophic Factor/biosynthesis
- Brain-Derived Neurotrophic Factor/metabolism
- Cell Survival/physiology
- Cochlear Nucleus/metabolism
- Cochlear Nucleus/pathology
- Cochlear Nucleus/physiopathology
- Disease Models, Animal
- Hearing Loss, Central/metabolism
- Hearing Loss, Central/pathology
- Hearing Loss, Central/physiopathology
- Hearing Loss, Noise-Induced/metabolism
- Hearing Loss, Noise-Induced/pathology
- Hearing Loss, Noise-Induced/physiopathology
- Male
- Noise/adverse effects
- Rats
- Rats, Inbred F344
- Receptor, trkB/biosynthesis
- Receptor, trkB/metabolism
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Affiliation(s)
- Hongning Wang
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, USA
| | - Thomas J. Brozoski
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL 62794-9629, USA
| | - Lynne Ling
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, USA
| | - Larry F. Hughes
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL 62794-9629, USA
| | - Donald M. Caspary
- Department of Pharmacology, Southern Illinois University School of Medicine, P.O. Box 19629, Springfield, IL 62794-9629, USA
- Department of Surgery, Southern Illinois University School of Medicine, Springfield, IL 62794-9629, USA
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19
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Hu H, Shao LR, Chavoshy S, Gu N, Trieb M, Behrens R, Laake P, Pongs O, Knaus HG, Ottersen OP, Storm JF. Presynaptic Ca2+-activated K+ channels in glutamatergic hippocampal terminals and their role in spike repolarization and regulation of transmitter release. J Neurosci 2001; 21:9585-97. [PMID: 11739569 PMCID: PMC6763057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023] Open
Abstract
Large-conductance Ca(2+)-activated K(+) channels (BK, also called Maxi-K or Slo channels) are widespread in the vertebrate nervous system, but their functional roles in synaptic transmission in the mammalian brain are largely unknown. By combining electrophysiology and immunogold cytochemistry, we demonstrate the existence of functional BK channels in presynaptic terminals in the hippocampus and compare their functional roles in somata and terminals of CA3 pyramidal cells. Double-labeling immunogold analysis with BK channel and glutamate receptor antibodies indicated that BK channels are targeted to the presynaptic membrane facing the synaptic cleft in terminals of Schaffer collaterals in stratum radiatum. Whole-cell, intracellular, and field-potential recordings from CA1 pyramidal cells showed that the presynaptic BK channels are activated by calcium influx and can contribute to repolarization of the presynaptic action potential (AP) and negative feedback control of Ca(2+) influx and transmitter release. This was observed in the presence of 4-aminopyridine (4-AP, 40-100 microm), which broadened the presynaptic compound action potential. In contrast, the presynaptic BK channels did not contribute significantly to regulation of action potentials or transmitter release under basal experimental conditions, i.e., without 4-AP, even at high stimulation frequencies. This is unlike the situation in the parent cell bodies (CA3 pyramidal cells), where BK channels contribute strongly to action potential repolarization. These results indicate that the functional role of BK channels depends on their subcellular localization.
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Affiliation(s)
- H Hu
- Institute of Physiology, University of Oslo, Blindern, N-0317 Oslo, Norway
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20
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Mohrmann R, Werner M, Hatt H, Gottmann K. Target-specific factors regulate the formation of glutamatergic transmitter release sites in cultured neocortical neurons. J Neurosci 1999; 19:10004-13. [PMID: 10559408 PMCID: PMC6782954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
Abstract
Synapse formation in the mammalian CNS is thought to involve specific target recognition processes between presynaptic and postsynaptic neurons leading to the establishment of defined neuronal circuits. To study the role of target neuron-specific factors in synaptogenesis, we used cocultures of presynaptic explants and dissociated target neurons from rat neocortex, which enabled us to selectively vary the postsynaptic target neurons. Cocultures containing target neurons that were obtained early during development [embryonic day 16 (E16)] were compared to cocultures containing target neurons that were obtained at a later embryonic stage (E19). Postsynaptic currents (PSCs) were evoked in target neurons by maximal extracellular stimulation in the presynaptic explant. The mean amplitudes of AMPA and NMDA receptor-mediated PSCs were sixfold reduced in E16 target neurons, whereas the mean amplitudes of GABA(A) receptor-mediated PSCs did not differ between E16 and E19 target neurons. This reduction was in part caused by an apparently twofold reduction in mean quantal amplitude, as shown by recording AMPA receptor-mediated miniature PSCs. In addition, a reduced number of glutamatergic release sites in E16 target neurons was revealed by synapsin I immunostaining of dendritic presynaptic terminals. No differences in mean release probability were observed between E16 and E19 target neurons. Thus, the formation of glutamatergic transmitter release sites was strongly influenced by target neuron-specific factors. The formation of functional GABAergic synapses, however, was independent of the type of target neurons, suggesting specific retrograde signaling during the establishment of glutamatergic synapses.
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Affiliation(s)
- R Mohrmann
- Lehrstuhl für Zellphysiologie, Ruhr-Universität Bochum, D-44780 Bochum, Germany
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21
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Wyszynski M, Kharazia V, Shanghvi R, Rao A, Beggs AH, Craig AM, Weinberg R, Sheng M. Differential regional expression and ultrastructural localization of alpha-actinin-2, a putative NMDA receptor-anchoring protein, in rat brain. J Neurosci 1998; 18:1383-92. [PMID: 9454847 PMCID: PMC6792723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/1997] [Revised: 12/01/1997] [Accepted: 12/01/1997] [Indexed: 02/06/2023] Open
Abstract
Fast chemical neurotransmission is dependent on ionotropic receptors that are concentrated and immobilized at specific postsynaptic sites. The mechanisms of receptor clustering and anchoring in neuronal synapses are poorly understood but presumably involve molecular linkage of membrane receptor proteins to the postsynaptic cytoskeleton. Recently the actin-binding protein alpha-actinin-2 was shown to bind directly to the NMDA receptor subunits NR1 and NR2B (), suggesting that alpha-actinin-2 may function to attach NMDA receptors to the actin cytoskeleton. Here we show that alpha-actinin-2 is localized specifically in glutamatergic synapses in cultured hippocampal neurons. By immunogold electron microscopy, alpha-actinin-2 is concentrated over the postsynaptic density (PSD) of numerous asymmetric synapses where it colocalizes with NR1 immunoreactivity. Thus alpha-actinin-2 is appropriately positioned at the ultrastructural level to function as a postsynaptic-anchoring protein for NMDA receptors. alpha-Actinin-2 is not, however, exclusively found at the PSD; immunogold labeling was also associated with filaments and the spine apparatus of dendritic spines and with microtubules in dendritic shafts. alpha-Actinin-2 showed marked differential regional expression in rat brain. For instance, the protein is expressed at much higher levels in dentate gyrus than in area CA1 of the hippocampus. This differential regional expression implies that glutamatergic synapses in various parts of the brain differ with respect to their alpha-actinin-2 content and thus, potentially, the extent of possible interaction between alpha-actinin-2 and the NMDA receptor.
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Affiliation(s)
- M Wyszynski
- Howard Hughes Medical Institute and Department of Neurobiology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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