51
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Bachmann C, Tetzlaff T, Duarte R, Morrison A. Firing rate homeostasis counteracts changes in stability of recurrent neural networks caused by synapse loss in Alzheimer's disease. PLoS Comput Biol 2020; 16:e1007790. [PMID: 32841234 PMCID: PMC7505475 DOI: 10.1371/journal.pcbi.1007790] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 09/21/2020] [Accepted: 03/17/2020] [Indexed: 11/19/2022] Open
Abstract
The impairment of cognitive function in Alzheimer's disease is clearly correlated to synapse loss. However, the mechanisms underlying this correlation are only poorly understood. Here, we investigate how the loss of excitatory synapses in sparsely connected random networks of spiking excitatory and inhibitory neurons alters their dynamical characteristics. Beyond the effects on the activity statistics, we find that the loss of excitatory synapses on excitatory neurons reduces the network's sensitivity to small perturbations. This decrease in sensitivity can be considered as an indication of a reduction of computational capacity. A full recovery of the network's dynamical characteristics and sensitivity can be achieved by firing rate homeostasis, here implemented by an up-scaling of the remaining excitatory-excitatory synapses. Mean-field analysis reveals that the stability of the linearised network dynamics is, in good approximation, uniquely determined by the firing rate, and thereby explains why firing rate homeostasis preserves not only the firing rate but also the network's sensitivity to small perturbations.
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Affiliation(s)
- Claudia Bachmann
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Tom Tetzlaff
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Renato Duarte
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
| | - Abigail Morrison
- Institute of Neuroscience and Medicine (INM-6) and Institute for Advanced Simulation (IAS-6) and JARA BRAIN Institute I, Jülich Research Centre, Jülich, Germany
- Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, Bochum, Germany
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52
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Verhage M, Sørensen JB. SNAREopathies: Diversity in Mechanisms and Symptoms. Neuron 2020; 107:22-37. [PMID: 32559416 DOI: 10.1016/j.neuron.2020.05.036] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 04/29/2020] [Accepted: 05/26/2020] [Indexed: 12/14/2022]
Abstract
Neuronal SNAREs and their key regulators together drive synaptic vesicle exocytosis and synaptic transmission as a single integrated membrane fusion machine. Human pathogenic mutations have now been reported for all eight core components, but patients are diagnosed with very different neurodevelopmental syndromes. We propose to unify these syndromes, based on etiology and mechanism, as "SNAREopathies." Here, we review the strikingly diverse clinical phenomenology and disease severity and the also remarkably diverse genetic mechanisms. We argue that disease severity generally scales with functional redundancy and, conversely, that the large effect of mutations in some SNARE genes is the price paid for extensive integration and exceptional specialization. Finally, we discuss how subtle differences in components being rate limiting in different types of neurons helps to explain the main symptoms.
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Affiliation(s)
- Matthijs Verhage
- Department of Functional Genomics, Vrije Universiteit (VU) Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, the Netherlands; Department of Clinical Genetics, UMC Amsterdam, De Boelelaan 1085, Amsterdam 1081 HV, the Netherlands.
| | - Jakob B Sørensen
- Department of Neuroscience, University of Copenhagen, 2200 Copenhagen N, Denmark.
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53
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Moulin TC, Rayêe D, Williams MJ, Schiöth HB. The Synaptic Scaling Literature: A Systematic Review of Methodologies and Quality of Reporting. Front Cell Neurosci 2020; 14:164. [PMID: 32612512 PMCID: PMC7309364 DOI: 10.3389/fncel.2020.00164] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 05/15/2020] [Indexed: 11/21/2022] Open
Abstract
The maintenance of the excitability of neurons and circuits is a fundamental process for healthy brain functions. One of the main homeostatic mechanisms responsible for such regulation is synaptic scaling. While this type of plasticity is well-characterized through a robust body of literature, there are no systematic evaluations of the methodological and reporting features from these studies. Our review yielded 168 articles directly investigating synaptic scaling mechanisms, which display relatively high impact, with a median impact factor of 7.76 for the publishing journals. Our methodological analysis identified that 86% of the articles made use of inhibitory interventions to induce synaptic scaling, while only 41% of those studies contain excitatory manipulations. To verify the effects of synaptic scaling, the most assessed outcome was miniature excitatory postsynaptic current (mEPSC) recordings, performed in 71% of the articles. We could also observe that the field is mostly focused on mechanistic studies of the synaptic scaling pathways (70%), rather than the interaction with other types of plasticity, such as Hebbian processes (4%). We found that more than half of the articles failed to describe simple features, such as regulatory compliance statements, ethics committee approval, or statements of conflict of interests. In light of these results, we discuss the strengths and pitfalls existing in synaptic scaling literature.
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Affiliation(s)
- Thiago C Moulin
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Danielle Rayêe
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Department of Ophthalmology and Visual Sciences, Albert Einstein College of Medicine, New York, NY, United States
| | - Michael J Williams
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden
| | - Helgi B Schiöth
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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54
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Moulin TC, Schiöth HB. Excitability, synaptic balance, and addiction: The homeostatic dynamics of ionotropic glutamatergic receptors in VTA after cocaine exposure. Behav Brain Funct 2020; 16:6. [PMID: 32522229 PMCID: PMC7288406 DOI: 10.1186/s12993-020-00168-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 06/06/2020] [Indexed: 11/10/2022] Open
Abstract
Glutamatergic AMPA and NMDA receptors in the ventral tegmental area (VTA) are central for cocaine first exposure and posterior craving maintenance. However, the exact rules that coordinate the synaptic dynamics of these receptors in dopaminergic VTA neurons and behavioral outcomes are poorly understood. Additionally, synaptic homeostatic plasticity is present in response to chronic excitability changes in neuronal circuits, adjusting the strength of synapses to stabilize the firing rate. Despite having correspondent mechanisms, little is known about the relationship between continuous cocaine exposure and homeostatic synaptic changes in the VTA neurons. Here, we assess the role of homeostatic mechanisms in the neurobiology of cocaine addiction by providing a brief overview of the parallels between cocaine-induced synaptic potentiation and long-term synaptic adaptations, focusing on the regulation of GluA1- and GluN1- containing receptors.
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Affiliation(s)
- Thiago C Moulin
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden.
| | - Helgi B Schiöth
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala, Sweden.,Institute for Translational Medicine and Biotechnology, Sechenov First Moscow State Medical University, Moscow, Russia
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55
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Dhuriya YK, Sharma D. Neuronal Plasticity: Neuronal Organization is Associated with Neurological Disorders. J Mol Neurosci 2020; 70:1684-1701. [PMID: 32504405 DOI: 10.1007/s12031-020-01555-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Accepted: 04/13/2020] [Indexed: 12/18/2022]
Abstract
Stimuli from stressful events, attention in the classroom, and many other experiences affect the functionality of the brain by changing the structure or reorganizing the connections between neurons and their communication. Modification of the synaptic transmission is a vital mechanism for generating neural activity via internal or external stimuli. Neuronal plasticity is an important driving force in neuroscience research, as it is the basic process underlying learning and memory and is involved in many other functions including brain development and homeostasis, sensorial training, and recovery from brain injury. Indeed, neuronal plasticity has been explored in numerous studies, but it is still not clear how neuronal plasticity affects the physiology and morphology of the brain. Thus, unraveling the molecular mechanisms of neuronal plasticity is essential for understanding the operation of brain functions. In this timeline review, we discuss the molecular mechanisms underlying different forms of synaptic plasticity and their association with neurodegenerative/neurological disorders as a consequence of alterations in neuronal plasticity.
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Affiliation(s)
- Yogesh Kumar Dhuriya
- Developmental Toxicology Laboratory, Systems Toxicology and Health Risk Assessment Group, CSIR-Indian Institute of Toxicology Research (CSIR-IITR) Vishvigyan Bhawan, 31, Mahatma Gandhi Marg, Lucknow, 226 001, India
| | - Divakar Sharma
- Department of Biochemistry, National JALMA Institute for Leprosy and Other Mycobacterial Diseases, Tajganj, Agra, India. .,CRF, Mass Spectrometry Laboratory, Kusuma School of Biological Sciences (KSBS), Indian Institute of Technology-Delhi (IIT-D), Delhi, 110016, India.
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56
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Luo S, Hou Y, Zhang Y, Ma T, Shao W, Xiao C. Adenosine A 2A Receptor Agonist PSB-0777 Modulates Synaptic Proteins and AMPA Receptor Expression in a Dose- and Time-Dependent Manner in Rat Primary Cortical Neurons. Biol Pharm Bull 2020; 43:1159-1171. [PMID: 32448843 DOI: 10.1248/bpb.b19-01007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Regulating synaptic formation and transmission is critical for the physiology and pathology of psychiatric disorders. The adenosine A2A receptor subtype has attracted widespread attention as a key regulator of neuropsychiatric activity, neuroprotection and injury. In this study, we systematically investigated the regulatory effects of a novel A2A receptor agonist, PSB-0777, on the expression of synaptic proteins and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid glutamate receptors (AMPA receptors) at the cellular level in a time- and dose-dependent manner. After 30 min of high-dose PSB-0777 stimulation, the expression of Synapsin-1 (Syn-1), postsynaptic density protein 95 (PSD95), and AMPA receptors and the number of synapses were rapidly and significantly increased in rat primary cortical neurons compared with the control. Sustained elevation was found in the low and medium-dose groups after 24 h and 3 d of treatment. In contrast, after stimulation with PSB-0777 for 3 consecutive days, the expression of Syn-1 was decreased, and PSD95, AMPA receptors and the number of synapses were no longer increased in the high-dose group. Our study focuses on the detailed and systematic regulation of synaptic proteins and AMPA receptors by an A2A receptor agonist, PSB-0777, which may result in both beneficial and detrimental effects on neurotransmission and neuroprotection and may contribute to the pathophysiology of psychiatric disorders related to A2A receptors. These experimental data may contribute to understanding of the mechanisms for neuroprotective and therapeutic effect of A2A receptor agonists.
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Affiliation(s)
| | | | | | - Tengfei Ma
- Yunnan University, School of Life Sciences, Center for Life Sciences
| | - Wenping Shao
- First Affiliated Hospital of Kunming Medical University, Department of Medical Examination
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57
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Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
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Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
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58
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Differential Scaling of Synaptic Molecules within Functional Zones of an Excitatory Synapse during Homeostatic Plasticity. eNeuro 2020; 7:ENEURO.0407-19.2020. [PMID: 32184300 PMCID: PMC7189482 DOI: 10.1523/eneuro.0407-19.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 03/03/2020] [Accepted: 03/05/2020] [Indexed: 11/29/2022] Open
Abstract
Homeostatic scaling is a form of synaptic plasticity where individual synapses scale their strengths to compensate for global suppression or elevation of neuronal activity. This process can be studied by measuring miniature EPSP (mEPSP) amplitudes and frequencies following the regulation of activity in neuronal cultures. Here, we demonstrate a quantitative approach to characterize multiplicative synaptic scaling using immunolabelling of hippocampal neuronal cultures treated with tetrodotoxin (TTX) or bicuculline to extract scaling factors for various synaptic proteins. This approach allowed us to directly examine the scaling of presynaptic and postsynaptic scaffolding molecules along with neurotransmitter receptors in primary cultures from mouse and rat hippocampal neurons. We show robust multiplicative scaling of synaptic scaffolding molecules namely, Shank2, PSD95, Bassoon, and AMPA receptor subunits and quantify their scaling factors. We use super-resolution microscopy to calculate scaling factors of surface expressed GluA2 within functional zones of the synapse and show that there is differential and correlated scaling of GluA2 levels within the spine, the postsynaptic density (PSD), and the perisynaptic regions. Our method opens a novel paradigm to quantify relative molecular changes of synaptic proteins within distinct subsynaptic compartments from a large number of synapses in response to alteration of neuronal activity, providing anatomic insights into the intricacies of variability in strength of individual synapses.
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59
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Tyssowski KM, Letai KC, Rendall SD, Tan C, Nizhnik A, Kaeser PS, Gray JM. Firing Rate Homeostasis Can Occur in the Absence of Neuronal Activity-Regulated Transcription. J Neurosci 2019; 39:9885-9899. [PMID: 31672790 PMCID: PMC6978944 DOI: 10.1523/jneurosci.1108-19.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 09/27/2019] [Accepted: 10/18/2019] [Indexed: 01/06/2023] Open
Abstract
Despite dynamic inputs, neuronal circuits maintain relatively stable firing rates over long periods. This maintenance of firing rate, or firing rate homeostasis, is likely mediated by homeostatic mechanisms such as synaptic scaling and regulation of intrinsic excitability. Because some of these homeostatic mechanisms depend on transcription of activity-regulated genes, including Arc and Homer1a, we hypothesized that activity-regulated transcription would be required for firing rate homeostasis. Surprisingly, however, we found that cultured mouse cortical neurons from both sexes grown on multi-electrode arrays homeostatically adapt their firing rates to persistent pharmacological stimulation even when activity-regulated transcription is disrupted. Specifically, we observed firing rate homeostasis in Arc knock-out neurons, as well as knock-out neurons lacking the activity-regulated transcription factors AP1 and SRF. Firing rate homeostasis also occurred normally during acute pharmacological blockade of transcription. Thus, firing rate homeostasis in response to increased neuronal activity can occur in the absence of neuronal-activity-regulated transcription.SIGNIFICANCE STATEMENT Neuronal circuits maintain relatively stable firing rates even in the face of dynamic circuit inputs. Understanding the molecular mechanisms that enable this firing rate homeostasis could potentially provide insight into neuronal diseases that present with an imbalance of excitation and inhibition. It has long been proposed that activity-regulated transcription could underlie firing rate homeostasis because activity-regulated genes turn on when neurons are above their target firing rates and include many genes that could regulate firing rate. Surprisingly, despite this prediction, we found that cortical neurons can undergo firing rate homeostasis in the absence of activity-regulated transcription, indicating that firing rate homeostasis can be controlled by non-transcriptional mechanisms.
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Affiliation(s)
| | | | | | - Chao Tan
- Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
| | | | - Pascal S Kaeser
- Neurobiology, Harvard Medical School, Boston, Massachusetts 02115
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60
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Dubes S, Favereaux A, Thoumine O, Letellier M. miRNA-Dependent Control of Homeostatic Plasticity in Neurons. Front Cell Neurosci 2019; 13:536. [PMID: 31866828 PMCID: PMC6906196 DOI: 10.3389/fncel.2019.00536] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 11/19/2019] [Indexed: 11/13/2022] Open
Abstract
Homeostatic plasticity is a form of plasticity in which neurons compensate for changes in neuronal activity through the control of key physiological parameters such as the number and the strength of their synaptic inputs and intrinsic excitability. Recent studies revealed that miRNAs, which are small non-coding RNAs repressing mRNA translation, participate in this process by controlling the translation of multiple effectors such as glutamate transporters, receptors, signaling molecules and voltage-gated ion channels. In this review, we present and discuss the role of miRNAs in both cell-wide and compartmentalized forms of homeostatic plasticity as well as their implication in pathological processes associated with homeostatic failure.
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Affiliation(s)
- Sandra Dubes
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Alexandre Favereaux
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Olivier Thoumine
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
| | - Mathieu Letellier
- University of Bordeaux, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
- CNRS, Interdisciplinary Institute for Neuroscience, UMR 5297, Bordeaux, France
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61
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Gutierrez DA, Vargas LM, Chandia-Cristi A, de la Fuente C, Leal N, Alvarez AR. c-Abl Deficiency Provides Synaptic Resiliency Against Aβ-Oligomers. Front Cell Neurosci 2019; 13:526. [PMID: 31849613 PMCID: PMC6902026 DOI: 10.3389/fncel.2019.00526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022] Open
Abstract
Spine pathology has been implicated in the early onset of Alzheimer’s disease (AD), where Aβ-Oligomers (AβOs) cause synaptic dysfunction and loss. Previously, we described that pharmacological inhibition of c-Abl prevents AβOs-induced synaptic alterations. Hence, this kinase seems to be a key element in AD progression. Here, we studied the role of c-Abl on dendritic spine morphological changes induced by AβOs using c-Abl null neurons (c-Abl-KO). First, we characterized the effect of c-Abl deficiency on dendritic spine density and found that its absence increases dendritic spine density. While AβOs-treatment reduces the spine number in both wild-type (WT) and c-Abl-KO neurons, AβOs-driven spine density loss was not affected by c-Abl. We then characterized AβOs-induced morphological changes in dendritic spines of c-Abl-KO neurons. AβOs induced a decrease in the number of mushroom spines in c-Abl-KO neurons while preserving the populations of immature stubby, thin, and filopodia spines. Furthermore, synaptic contacts evaluated by PSD95/Piccolo clustering and cell viability were preserved in AβOs-exposed c-Abl-KO neurons. In conclusion, our results indicate that in the presence of AβOs c-Abl participates in synaptic contact removal, increasing susceptibility to AβOs damage. Its deficiency increases the immature spine population reducing AβOs-induced synapse elimination. Therefore, c-Abl signaling could be a relevant actor in the early stages of AD.
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Affiliation(s)
- Daniela A Gutierrez
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Lina M Vargas
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - América Chandia-Cristi
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Catalina de la Fuente
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Nancy Leal
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Alejandra R Alvarez
- Cell Signaling Laboratory, Faculty of Biological Science, Department of Cell and Molecular Biology, Center for Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile
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62
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Bird CW, Barber MJ, Post HR, Jacquez B, Chavez GJ, Faturos NG, Valenzuela CF. Neonatal ethanol exposure triggers apoptosis in the murine retrosplenial cortex: Role of inhibition of NMDA receptor-driven action potential firing. Neuropharmacology 2019; 162:107837. [PMID: 31689422 DOI: 10.1016/j.neuropharm.2019.107837] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/07/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023]
Abstract
Exposure to ethanol during the last trimester equivalent of human pregnancy causes apoptotic neurodegeneration in the developing brain, an effect that is thought to be mediated, in part, by inhibition of NMDA receptors. However, NMDA receptors can rapidly adapt to the acute effects of ethanol and are ethanol resistant in some populations of developing neurons. Here, we characterized the effect of ethanol on NMDA and non-NMDA receptor-mediated synaptic transmission in the retrosplenial cortex (RSC), a brain region involved in the integration of different modalities of spatial information that is among the most sensitive regions to ethanol-induced neurodegeneration. A single 4-h exposure to ethanol vapor of 7-day-old transgenic mice that express the Venus fluorescent protein in interneurons triggered extensive apoptosis in the RSC. Slice electrophysiological recordings showed that bath-applied ethanol inhibits NMDA and non-NMDA receptor excitatory postsynaptic currents (EPSCs) in pyramidal neurons and interneurons; however, we found no evidence of acute tolerance development to this effect after the 4-h in-vivo ethanol vapor exposure. Acute bath application of ethanol reduced action potential firing evoked by synaptic stimulation to a greater extent in pyramidal neurons than interneurons. Submaximal inhibition of NMDA EPSCs, but not non-NMDA EPSCs, mimicked the acute effect of ethanol on synaptically-evoked action potential firing. These findings indicate that partial inhibition of NMDA receptors by ethanol has sizable effects on the excitability of glutamatergic and GABAergic neurons in the developing RSC, and suggest that positive allosteric modulators of these receptors could ameliorate ethanol intoxication-induced neurodegeneration during late stages of fetal development.
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Affiliation(s)
- Clark W Bird
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Megan J Barber
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Hilary R Post
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Belkis Jacquez
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Glenna J Chavez
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - Nicholas G Faturos
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | - C Fernando Valenzuela
- Department of Neurosciences, School of Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA.
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63
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Robinson S, Courtney MJ. Spatial quantification of the synaptic activity phenotype across large populations of neurons with Markov random fields. Bioinformatics 2019; 34:3196-3204. [PMID: 29897415 DOI: 10.1093/bioinformatics/bty322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Accepted: 04/25/2018] [Indexed: 11/12/2022] Open
Abstract
Motivation The collective and co-ordinated synaptic activity of large neuronal populations is relevant to neuronal development as well as a range of neurological diseases. Quantification of synaptically-mediated neuronal signalling permits further downstream analysis as well as potential application in target validation and in vitro screening assays. Our aim is to develop a phenotypic quantification for neuronal activity imaging data of large populations of neurons, in particular relating to the spatial component of the activity. Results We extend the use of Markov random field (MRF) models to achieve this aim. In particular, we consider Bayesian posterior densities of model parameters in Gaussian MRFs to directly model changes in calcium fluorescence intensity rather than using spike trains. The basis of our model is defining neuron 'neighbours' by the relative spatial positions of the neuronal somata as obtained from the image data whereas previously this has been limited to defining an artificial square grid across the field of view and spike binning. We demonstrate that our spatial phenotypic quantification is applicable for both in vitro and in vivo data consisting of thousands of neurons over hundreds of time points. We show how our approach provides insight beyond that attained by conventional spike counting and discuss how it could be used to facilitate screening assays for modifiers of disease-associated defects of communication between cells. Availability and implementation We supply the MATLAB code and data to obtain all of the results in the paper. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Sean Robinson
- Department of Mathematics and Statistics, University of Turku, Turku, Finland.,Université Grenoble Alpes, CEA, INSERM, Biology of Cancer and Infection UMR S 1036, Grenoble, France
| | - Michael J Courtney
- Neuronal Signalling Lab, Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, Turku, Finland.,Screening Unit, Turku Centre for Biotechnology, University of Turku and Åbo Akademi University, and Institute of Biomedicine, University of Turku, Turku, Finland.,Turku Brain and Mind Center, University of Turku and Åbo Akademi University, Turku, Finland
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64
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Henkel AW, Mouihate A, Welzel O. Differential Release of Exocytosis Marker Dyes Indicates Stimulation-Dependent Regulation of Synaptic Activity. Front Neurosci 2019; 13:1047. [PMID: 31632237 PMCID: PMC6783566 DOI: 10.3389/fnins.2019.01047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/18/2019] [Indexed: 02/05/2023] Open
Abstract
There is a general consensus that synaptic vesicular release by a full collapse process is the primary machinery of synaptic transmission. However, competing view suggests that synaptic vesicular release operates via a kiss-and-run mechanism. By monitoring the release dynamics of a synaptic vesicular marker, FM1-43 from individual synapses in hippocampal neurons, we found evidence that the release of synaptic vesicle was delayed by several seconds after the start of field stimulation. This phenomenon was associated with modified opening kinetics of fusion pores. Detailed analysis revealed that some synapses were completely inactive for a few seconds after stimulation, despite immediate calcium influx. This delay in vesicular release was modulated by various stimulation protocols and different frequencies, indicating an activity-dependent regulation mechanism for neurotransmitter exocytosis. Staurosporine, a drug known to induce “kiss-and-run” exocytosis, increased the proportion of delayed synapses as well as the delay duration, while fluoxetine acted contrarily. Besides being a serotonin reuptake inhibitor, it directly enhanced vesicle mobilization and reduced synaptic fatigue. Exocytosis was never delayed, when it was monitored with pH-sensitive probes, synaptopHlourin and αSyt-CypHerE5 antibody, indicating an instantaneous formation of a fusion pore that allowed rapid equilibration of vesicular lumenal pH but prevented FM1-43 release because of its slow dissociation from the inner vesicular membrane. Our observations suggest that synapses operate via a sequential “kiss-and-run” and “full-collapse” exocytosis mechanism. The initially narrow vesicular pore allows the equilibration of intravesicular pH which then progresses toward full fusion, causing FM1-43 release.
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Affiliation(s)
- Andreas W Henkel
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Abdeslam Mouihate
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Oliver Welzel
- Department of Psychiatry and Psychotherapy, University Hospital Erlangen, Erlangen, Germany
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Fernandez-Albert J, Lipinski M, Lopez-Cascales MT, Rowley MJ, Martin-Gonzalez AM, Del Blanco B, Corces VG, Barco A. Immediate and deferred epigenomic signatures of in vivo neuronal activation in mouse hippocampus. Nat Neurosci 2019; 22:1718-1730. [PMID: 31501571 PMCID: PMC6875776 DOI: 10.1038/s41593-019-0476-2] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 07/23/2019] [Indexed: 11/08/2022]
Abstract
Activity-driven transcription plays an important role in many brain processes, including those underlying memory and epilepsy. Here we combine genetic tagging of nuclei and ribosomes with RNA sequencing, chromatin immunoprecipitation with sequencing, assay for transposase-accessible chromatin using sequencing and Hi-C to investigate transcriptional and chromatin changes occurring in mouse hippocampal excitatory neurons at different time points after synchronous activation during seizure and sparse activation by novel context exploration. The transcriptional burst is associated with an increase in chromatin accessibility of activity-regulated genes and enhancers, de novo binding of activity-regulated transcription factors, augmented promoter-enhancer interactions and the formation of gene loops that bring together the transcription start site and transcription termination site of induced genes and may sustain the fast reloading of RNA polymerase complexes. Some chromatin occupancy changes and interactions, particularly those driven by AP1, remain long after neuronal activation and could underlie the changes in neuronal responsiveness and circuit connectivity observed in these neuroplasticity paradigms, perhaps thereby contributing to metaplasticity in the adult brain.
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Affiliation(s)
- Jordi Fernandez-Albert
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain
| | - Michal Lipinski
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain
| | - María T Lopez-Cascales
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain
| | - M Jordan Rowley
- Department of Biology, Emory University, Atlanta, GA, USA
- Department of Genetics, Cell Biology and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Ana M Martin-Gonzalez
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain
- Nencki Institute of Experimental Biology PAS, Warsaw, Poland
| | - Beatriz Del Blanco
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain
| | | | - Angel Barco
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, Sant Joan d'Alacant, Alicante, Spain.
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66
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Joshi VV, Patel ND, Rehan MA, Kuppa A. Mysterious Mechanisms of Memory Formation: Are the Answers Hidden in Synapses? Cureus 2019; 11:e5795. [PMID: 31728242 PMCID: PMC6827877 DOI: 10.7759/cureus.5795] [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: 08/13/2019] [Accepted: 09/28/2019] [Indexed: 12/18/2022] Open
Abstract
After decades of research on memory formation and retention, we are still searching for the definite concept and process behind neuroplasticity. This review article will address the relationship between synapses, memory formation, and memory retention and their genetic correlations. In the last six decades, there have been enormous improvements in the neurochemistry domain, especially in the area of neural plasticity. In the central nervous system, the complexity of the synapses between neurons allows communication among them. It is believed that each time certain types of sensory signals pass through sequences of synapses, these synapses can transmit the same signals more efficiently the following time. The concept of Hebb synapse has provided revolutionary thinking about the nature of neural mechanisms of learning and memory formation. To improve the local circuitry for memory formation and behavioral change and stabilization in the mammalian central nervous system, long-term potentiation and long-term depression are the crucial components of Hebbian plasticity. In this review, we will be discussing the role of glutamatergic synapses, engram cells, cytokines, neuropeptides, neurosteroids and many aspects, covering the synaptic basis of memory. Lastly, we have tried to cover the etiology of neurodegenerative disorders due to synaptic dysfunction. To enhance pharmacological interventions for neurodegenerative diseases, we need more research in this direction. With the help of technology, and a better understanding of the disease etiology, not only can we identify the missing pieces of synaptic functions, but we might also cure or even prevent serious neurodegenerative diseases like Alzheimer's disease (AD).
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Affiliation(s)
- Viraj V Joshi
- Neuropsychiatry, California Instititute of Behavioral Neurosciences and Psychology, Fairfield, USA
| | - Nishita D Patel
- Research, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Muhammad Awais Rehan
- Miscellenous, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Annapurna Kuppa
- Internal Medicine and Gastroenterology, University of Michigan, Ann Arbor, USA
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67
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Mariottini C, Munari L, Gunzel E, Seco JM, Tzavaras N, Hansen J, Stern SA, Gao V, Aleyasin H, Sharma A, Azeloglu EU, Hodes GE, Russo SJ, Huff V, Birtwistle MR, Blitzer RD, Alberini CM, Iyengar R. Wilm's tumor 1 promotes memory flexibility. Nat Commun 2019; 10:3756. [PMID: 31434897 PMCID: PMC6704057 DOI: 10.1038/s41467-019-11781-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 07/31/2019] [Indexed: 02/06/2023] Open
Abstract
Under physiological conditions, strength and persistence of memory must be regulated in order to produce behavioral flexibility. In fact, impairments in memory flexibility are associated with pathologies such as post-traumatic stress disorder or autism; however, the underlying mechanisms that enable memory flexibility are still poorly understood. Here, we identify transcriptional repressor Wilm's Tumor 1 (WT1) as a critical synaptic plasticity regulator that decreases memory strength, promoting memory flexibility. WT1 is activated in the hippocampus following induction of long-term potentiation (LTP) or learning. WT1 knockdown enhances CA1 neuronal excitability, LTP and long-term memory whereas its overexpression weakens memory retention. Moreover, forebrain WT1-deficient mice show deficits in both reversal, sequential learning tasks and contextual fear extinction, exhibiting impaired memory flexibility. We conclude that WT1 limits memory strength or promotes memory weakening, thus enabling memory flexibility, a process that is critical for learning from new experiences.
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Affiliation(s)
- Chiara Mariottini
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA.
- Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA.
| | - Leonardo Munari
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Ellen Gunzel
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
- Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Joseph M Seco
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Nikos Tzavaras
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Jens Hansen
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
- Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Sarah A Stern
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
- Center for Neural Science, New York University, New York, 10003, NY, USA
| | - Virginia Gao
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
- Center for Neural Science, New York University, New York, 10003, NY, USA
| | - Hossein Aleyasin
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Ali Sharma
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Evren U Azeloglu
- Department of Medicine, Division of Nephrology, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Georgia E Hodes
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Scott J Russo
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Vicki Huff
- Department of Genetics, M.D. Anderson Cancer Center, University of Texas, Houston, 77030, TX, USA
| | - Marc R Birtwistle
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
- Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Robert D Blitzer
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA
| | - Cristina M Alberini
- Department of Neuroscience, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA.
- Center for Neural Science, New York University, New York, 10003, NY, USA.
| | - Ravi Iyengar
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA.
- Systems Biology Center, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, 10029, NY, USA.
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68
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Wang G, Zhong J, Guttieres D, Man HY. Non-scaling regulation of AMPA receptors in homeostatic synaptic plasticity. Neuropharmacology 2019; 158:107700. [PMID: 31283924 DOI: 10.1016/j.neuropharm.2019.107700] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 06/10/2019] [Accepted: 07/04/2019] [Indexed: 11/28/2022]
Abstract
Homeostatic synaptic plasticity (HSP) as an activity-dependent negative feedback regulation of synaptic strength plays important roles in the maintenance of neuronal and neural circuitry stability. A primary cellular substrate for HSP expression is alterations in synaptic accumulation of glutamatergic α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR). It is widely believed that during HSP, AMPAR accumulation changes with the same proportion at each synapse of a neuron, a process known as synaptic scaling. However, direct evidence on AMPAR synaptic scaling remains largely lacking. Here we report a direct examination of inactivity-induced homeostatic scaling of AMPAR at individual synapse by live-imaging. Surprisingly, instead of uniform up-scaling, a scattered pattern of changes in synaptic AMPAR was observed in cultured rat hippocampal neurons. While the majority of synapses showed up-regulation after activity inhibition, a reduction of AMPAR could be detected in certain synapses. More importantly, among the up-regulated synapses, a wide range of AMPAR changes was observed in synapses of the same neuron. We also found that synapses with higher levels of pre-existing AMPAR tend to be up-regulated by lesser extents, whereas the locations of synapses relative to the soma seem not affecting AMPAR scaling strengths. In addition, we observed strong competition between neighboring synapses during HSP. These results reveal that synaptic AMPAR may not be scaled during HSP, suggesting novel molecular mechanisms for information processing and storage at synapses.
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Affiliation(s)
- Guan Wang
- Department of Biology, Boston University, Boston, MA, USA; School of Pharmaceutical Sciences, Tsinghua University, Beijing, China
| | - Jia Zhong
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | | | - Heng-Ye Man
- Department of Biology, Boston University, Boston, MA, USA; Department of Pharmacology & Experimental Therapeutics, Boston University School of Medicine, Boston, MA, USA.
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69
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Effects of chronic mild stress induced depression on synaptic plasticity in mouse hippocampus. Behav Brain Res 2019; 365:26-35. [DOI: 10.1016/j.bbr.2019.02.044] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 02/23/2019] [Accepted: 02/26/2019] [Indexed: 12/11/2022]
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70
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Intraocular Neurografts as a Model for Studying of Organization of Synaptic Connections in a Denervated Brain Area. Bull Exp Biol Med 2019; 166:816-819. [PMID: 31020582 DOI: 10.1007/s10517-019-04447-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Indexed: 10/26/2022]
Abstract
Intraocular neurografts of the septal region of rats were used as the model of deafferentiated brain area where the lack of adequate innervation is compensated for own interneuronal connections. Septum anlage from the brain of a 17-day fetus served as the donor material. The grafts developing in the anterior eye chamber over 3 months represented well-differentiated samples of the nervous tissue. A comparative morphometric study of the tripartite organization of synapses in the grafts and in the septum in situ was conducted. In the grafts, the mean volume and perimeter of synaptic terminals were below the normal. At the same time, postsynaptic densities did not differ from the control. A significant difference was found in the degree of surrounding of presynaptic terminals by astrocytic processes: in the grafts this parameter was higher by 1.8 times. Our results attest to an important role of perisynaptic glia in the formation of functionally active synaptic contacts with unusual neuronal targets.
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71
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MicroRNA-186-5p controls GluA2 surface expression and synaptic scaling in hippocampal neurons. Proc Natl Acad Sci U S A 2019; 116:5727-5736. [PMID: 30808806 DOI: 10.1073/pnas.1900338116] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Homeostatic synaptic scaling is a negative feedback response to fluctuations in synaptic strength induced by developmental or learning-related processes, which maintains neuronal activity stable. Although several components of the synaptic scaling apparatus have been characterized, the intrinsic regulatory mechanisms promoting scaling remain largely unknown. MicroRNAs may contribute to posttranscriptional control of mRNAs implicated in different stages of synaptic scaling, but their role in these mechanisms is still undervalued. Here, we report that chronic blockade of glutamate receptors of the AMPA and NMDA types in hippocampal neurons in culture induces changes in the neuronal mRNA and miRNA transcriptomes, leading to synaptic upscaling. Specifically, we show that synaptic activity blockade persistently down-regulates miR-186-5p. Moreover, we describe a conserved miR-186-5p-binding site within the 3'UTR of the mRNA encoding the AMPA receptor GluA2 subunit, and demonstrate that GluA2 is a direct target of miR-186-5p. Overexpression of miR-186 decreased GluA2 surface levels, increased synaptic expression of GluA2-lacking AMPA receptors, and blocked synaptic scaling, whereas inhibition of miR-186-5p increased GluA2 surface levels and the amplitude and frequency of AMPA receptor-mediated currents, and mimicked excitatory synaptic scaling induced by synaptic inactivity. Our findings elucidate an activity-dependent miRNA-mediated mechanism for regulation of AMPA receptor expression.
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72
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Moulin TC, Petiz LL, Rayêe D, Winne J, Maia RG, Lima da Cruz RV, Amaral OB, Leão RN. Chronic in vivo optogenetic stimulation modulates neuronal excitability, spine morphology, and Hebbian plasticity in the mouse hippocampus. Hippocampus 2019; 29:755-761. [DOI: 10.1002/hipo.23080] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 12/19/2018] [Accepted: 01/26/2019] [Indexed: 11/09/2022]
Affiliation(s)
- Thiago C. Moulin
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Lyvia L. Petiz
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Danielle Rayêe
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | - Jessica Winne
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
| | - Roberto G. Maia
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | | | - Olavo B. Amaral
- Leopoldo de Meis Institute of Medical Biochemistry, Federal University of Rio de Janeiro; Rio de Janeiro Brazil
| | - Richardson N. Leão
- Brain Institute, Federal University of Rio Grande do Norte; Rio Grande do Norte Brazil
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Abstract
Cognitive impairments reported across psychiatric conditions (ie, major depressive disorder, bipolar disorder, schizophrenia, and posttraumatic stress disorder) strongly impair the quality of life of patients and the recovery of those conditions. There is therefore a great need for consideration for cognitive dysfunction in the management of psychiatric disorders. The redundant pattern of cognitive impairments across such conditions suggests possible shared mechanisms potentially leading to their development. Here, we review for the first time the possible role of inflammation in cognitive dysfunctions across psychiatric disorders. Raised inflammatory processes (microglia activation and elevated cytokine levels) across diagnoses could therefore disrupt neurobiological mechanisms regulating cognition, including Hebbian and homeostatic plasticity, neurogenesis, neurotrophic factor, the HPA axis, and the kynurenine pathway. This redundant association between elevated inflammation and cognitive alterations across psychiatric disorders hence suggests that a cross-disorder approach using pharmacological and nonpharmacological (ie, physical activity and nutrition) anti-inflammatory/immunomodulatory strategies should be considered in the management of cognition in psychiatry.
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74
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Landi S, Petrucco L, Sicca F, Ratto GM. Transient Cognitive Impairment in Epilepsy. Front Mol Neurosci 2019; 11:458. [PMID: 30666185 PMCID: PMC6330286 DOI: 10.3389/fnmol.2018.00458] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 11/28/2018] [Indexed: 02/05/2023] Open
Abstract
Impairments of the dialog between excitation and inhibition (E/I) is commonly associated to neuropsychiatric disorders like autism, bipolar disorders and epilepsy. Moderate levels of hyperexcitability can lead to mild alterations of the EEG and are often associated with cognitive deficits even in the absence of overt seizures. Indeed, various testing paradigms have shown degraded performances in presence of acute or chronic non-ictal epileptiform activity. Evidences from both animal models and the clinics suggest that anomalous activity can cause cognitive deficits by transiently disrupting cortical processing, independently from the underlying etiology of the disease. Here, we will review our understanding of the influence of an abnormal EEG activity on brain computation in the context of the available clinical data and in genetic or pharmacological animal models.
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Affiliation(s)
- Silvia Landi
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
| | - Luigi Petrucco
- Graduate School of Systemic Neurosciences, Ludwig Maximilian University of Munich (LMU), Munich, Germany
| | - Federico Sicca
- Department of Developmental Neuroscience, Fondazione IRCCS Stella Maris, Pisa, Italy
| | - Gian Michele Ratto
- NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Pisa, Italy
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75
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Parkinson GT, Hanley JG. Mechanisms of AMPA Receptor Endosomal Sorting. Front Mol Neurosci 2018; 11:440. [PMID: 30568574 PMCID: PMC6289981 DOI: 10.3389/fnmol.2018.00440] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Accepted: 11/13/2018] [Indexed: 12/21/2022] Open
Abstract
The regulation of synaptic AMPA receptors (AMPARs) is critical for excitatory synaptic transmission, synaptic plasticity and the consequent formation of neural circuits during brain development and their modification during learning and memory processes. The number of synaptic AMPARs is regulated through endocytosis, exocytosis and endosomal sorting that results in recycling back to the plasma membrane or degradation in the lysosome. Hence, endo-lysosomal sorting is vitally important in maintaining AMPAR expression at the synapse, and the dynamic regulation of these trafficking events is a key component of synaptic plasticity. A reduction in synaptic strength such as in long-term depression (LTD) involves AMPAR sorting to lysosomes to reduce synaptic AMPAR number, whereas long-term potentiation (LTP) involves an increase in AMPAR recycling to increase the number of AMPARs at synapses. Here, we review our current understanding of the endosomal trafficking routes taken by AMPARs, and the mechanisms involved in AMPAR endosomal sorting, focussing on the numerous AMPAR associated proteins that have been implicated in this complex process. We also discuss how these events are dysregulated in brain disorders.
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Affiliation(s)
- Gabrielle T Parkinson
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
| | - Jonathan G Hanley
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
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76
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Cholinergic Mechanisms of Target Oddball Stimuli Detection: The Late "P300-Like" Event-Related Potential in Rats. Neural Plast 2018; 2018:4270263. [PMID: 30410536 PMCID: PMC6206555 DOI: 10.1155/2018/4270263] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/27/2018] [Accepted: 07/16/2018] [Indexed: 11/22/2022] Open
Abstract
Event-related potentials (ERPs) and oscillations (EROs) provide powerful tools for studying the brain's synaptic function underlying information processing. The P300 component of ERPs indexing attention and working memory shows abnormal amplitude and latency in neurological and psychiatric diseases that are sensitive to pharmacological agents. In the active auditory oddball discriminant paradigm, behavior and auditory-evoked potentials (AEPs) were simultaneously recorded in awake rats to investigate whether P300-like potentials generated in rats responding to rare target oddball tones are sensitive to subcutaneous modulation of the cholinergic tone by donepezil (1 mg/kg) and scopolamine (0.64 mg/kg). After operant training, rats consistently discriminate rare target auditory stimuli from frequent irrelevant nontarget auditory stimuli by a higher level of correct lever presses (i.e., accuracy) in target trials associated with a food reward. Donepezil attenuated the disruptive effect of scopolamine on the level of accuracy and premature responses in target trials. Larger P300-like peaks with early and late components were revealed in correct rare target stimuli trials as compared to frequent tones. Donepezil enhanced the peak amplitude of the P300-like component to target stimuli and evoked slow theta and gamma oscillations, whereas scopolamine altered the amplitude of the P300-like component and EROs to target stimuli. Pretreatment with donepezil attenuated effects of scopolamine on the peak amplitude of the P300-like component and on EROs. This study provides evidence that AEP P300-like responses can be elicited by rats engaged in attentive and memory processing of target stimuli and outline the relevance of the cholinergic system in stimulus discrimination processing. The findings highlight the sensitivity of this translational index for investigating brain circuits and/or novel pharmacological agents, which modulate cholinergic transmission associated with increased allocation of attentional resources.
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77
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Hanley JG. The Regulation of AMPA Receptor Endocytosis by Dynamic Protein-Protein Interactions. Front Cell Neurosci 2018; 12:362. [PMID: 30364226 PMCID: PMC6193100 DOI: 10.3389/fncel.2018.00362] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 09/25/2018] [Indexed: 11/13/2022] Open
Abstract
The precise regulation of AMPA receptor (AMPAR) trafficking in neurons is crucial for excitatory neurotransmission, synaptic plasticity and the consequent formation and modification of neural circuits during brain development and learning. Clathrin-mediated endocytosis (CME) is an essential trafficking event for the activity-dependent removal of AMPARs from the neuronal plasma membrane, resulting in a reduction in synaptic strength known as long-term depression (LTD). The regulated AMPAR endocytosis that underlies LTD is caused by specific modes of synaptic activity, most notably stimulation of NMDA receptors (NMDARs) and metabotropic glutamate receptors (mGluRs). Numerous proteins associate with AMPAR subunits, directly or indirectly, to control their trafficking, and therefore the regulation of these protein-protein interactions in response to NMDAR or mGluR signaling is a critical feature of synaptic plasticity. This article reviews the protein-protein interactions that are dynamically regulated during synaptic plasticity to modulate AMPAR endocytosis, focussing on AMPAR binding proteins and proteins that bind the core endocytic machinery. In addition, the mechanisms for the regulation of protein-protein interactions are considered, as well as the functional consequences of these dynamic interactions on AMPAR endocytosis.
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Affiliation(s)
- Jonathan G Hanley
- Centre for Synaptic Plasticity and School of Biochemistry, University of Bristol, Bristol, United Kingdom
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78
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Hobbiss AF, Ramiro-Cortés Y, Israely I. Homeostatic Plasticity Scales Dendritic Spine Volumes and Changes the Threshold and Specificity of Hebbian Plasticity. iScience 2018; 8:161-174. [PMID: 30317078 PMCID: PMC6187013 DOI: 10.1016/j.isci.2018.09.015] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 08/03/2018] [Accepted: 09/17/2018] [Indexed: 11/27/2022] Open
Abstract
Information is encoded in neural networks through changes in synaptic weights. Synaptic learning rules involve a combination of rapid Hebbian plasticity and slower homeostatic synaptic plasticity that regulates neuronal activity through global synaptic scaling. Hebbian and homeostatic plasticity have been extensively investigated, whereas much less is known about their interaction. Here we investigated structural and functional consequences of homeostatic plasticity at dendritic spines of mouse hippocampal neurons. We found that prolonged activity blockade induced spine growth, paralleling synaptic strength increases. Following activity blockade, glutamate uncaging-mediated stimulation at single spines led to size-dependent structural potentiation: smaller spines underwent robust growth, whereas larger spines remained unchanged. Moreover, spines near the stimulated spine exhibited volume changes following homeostatic plasticity, indicating that there was a breakdown of input specificity following homeostatic plasticity. Overall, these findings demonstrate that Hebbian and homeostatic plasticity interact to shape neural connectivity through non-uniform structural plasticity at inputs. Chronic activity blockade leads to enlarged hippocampal spines and structural scaling Homeostatic plasticity affects subsequent Hebbian plasticity according to size of spines Neighbors also grow after potentiation of single spines, compromising input specificity
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Affiliation(s)
| | - Yazmin Ramiro-Cortés
- Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal; Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad Universitaria, Circuito exterior s/n, Ciudad de México 04510, México
| | - Inbal Israely
- Champalimaud Centre for the Unknown, Lisbon 1400-038, Portugal; Department of Pathology and Cell Biology in the Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Neuroscience, College of Physicians & Surgeons, Columbia University, New York, NY 10032, USA.
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79
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Gorodetski L, Zeira R, Lavian H, Korngreen A. Long-term plasticity of glutamatergic input from the subthalamic nucleus to the entopeduncular nucleus. Eur J Neurosci 2018; 48:2139-2151. [PMID: 30103273 DOI: 10.1111/ejn.14105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 07/24/2018] [Accepted: 08/01/2018] [Indexed: 11/26/2022]
Abstract
The hyperdirect pathway of the basal ganglia bypasses the striatum, and delivers cortical information directly to the subthalamic nucleus (STN). In rodents, the STN excites the two output nuclei of the basal ganglia, the entopeduncular nucleus (EP) and the substantia nigra reticulata (SNr). Thus, during hyperdirect pathway activation, the STN drives EP firing inhibiting the thalamus. We hypothesized that STN activity could induce long-term changes to the STN->EP synapse. To test this hypothesis, we recorded in the whole-cell mode from neurons in the EP in acute brain slices from rats while electrically stimulating the STN. Repetitive pre-synaptic stimulation generated modest long-term depression (LTD) in the STN->EP synapse. However, pairing EP firing with STN stimulation generated robust LTD that manifested for pre-before post-as well as for post- before pre-synaptic pairing. This LTD was highly sensitive to the time difference and was not detected at a time delay of 10 ms. To investigate whether post-synaptic calcium levels were important for LTD induction, we made dendritic recordings from EP neurons that revealed action potential back-propagation and dendritic calcium transients. Buffering the dendritic calcium concentration in the EP neurons with EGTA generated long term potentiation instead of LTD. Finally, mild LTD could be induced by post-synaptic activity alone that was blocked by an endocannabinoid 1 (CB1) receptor blocker. These results thus suggest there may be an adaptive mechanism for buffering the impact of the hyperdirect pathway on basal ganglia output which could contribute to the de-correlation of STN and EP firing.
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Affiliation(s)
- Lilach Gorodetski
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Reut Zeira
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel
| | - Hagar Lavian
- The Leslie and Susan Gonda Interdisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
| | - Alon Korngreen
- The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat Gan, Israel.,The Leslie and Susan Gonda Interdisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
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80
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Pál B. Involvement of extrasynaptic glutamate in physiological and pathophysiological changes of neuronal excitability. Cell Mol Life Sci 2018; 75:2917-2949. [PMID: 29766217 PMCID: PMC11105518 DOI: 10.1007/s00018-018-2837-5] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Revised: 04/27/2018] [Accepted: 05/07/2018] [Indexed: 12/14/2022]
Abstract
Glutamate is the most abundant neurotransmitter of the central nervous system, as the majority of neurons use glutamate as neurotransmitter. It is also well known that this neurotransmitter is not restricted to synaptic clefts, but found in the extrasynaptic regions as ambient glutamate. Extrasynaptic glutamate originates from spillover of synaptic release, as well as from astrocytes and microglia. Its concentration is magnitudes lower than in the synaptic cleft, but receptors responding to it have higher affinity for it. Extrasynaptic glutamate receptors can be found in neuronal somatodendritic location, on astroglia, oligodendrocytes or microglia. Activation of them leads to changes of neuronal excitability with different amplitude and kinetics. Extrasynaptic glutamate is taken up by neurons and astrocytes mostly via EAAT transporters, and astrocytes, in turn metabolize it to glutamine. Extrasynaptic glutamate is involved in several physiological phenomena of the central nervous system. It regulates neuronal excitability and synaptic strength by involving astroglia; contributing to learning and memory formation, neurosecretory and neuromodulatory mechanisms, as well as sleep homeostasis.The extrasynaptic glutamatergic system is affected in several brain pathologies related to excitotoxicity, neurodegeneration or neuroinflammation. Being present in dementias, neurodegenerative and neuropsychiatric diseases or tumor invasion in a seemingly uniform way, the system possibly provides a common component of their pathogenesis. Although parts of the system are extensively discussed by several recent reviews, in this review I attempt to summarize physiological actions of the extrasynaptic glutamate on neuronal excitability and provide a brief insight to its pathology for basic understanding of the topic.
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Affiliation(s)
- Balázs Pál
- Department of Physiology, Faculty of Medicine, University of Debrecen, Nagyerdei krt 98, Debrecen, 4012, Hungary.
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81
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Ge Y, Kang Y, Cassidy RM, Moon KM, Lewis R, Wong ROL, Foster LJ, Craig AM. Clptm1 Limits Forward Trafficking of GABA A Receptors to Scale Inhibitory Synaptic Strength. Neuron 2018; 97:596-610.e8. [PMID: 29395912 DOI: 10.1016/j.neuron.2017.12.038] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 11/17/2017] [Accepted: 12/22/2017] [Indexed: 12/11/2022]
Abstract
In contrast with numerous studies of glutamate receptor-associated proteins and their involvement in the modulation of excitatory synapses, much less is known about mechanisms controlling postsynaptic GABAA receptor (GABAAR) numbers. Using tandem affinity purification from tagged GABAAR γ2 subunit transgenic mice and proteomic analysis, we isolated several GABAAR-associated proteins, including Cleft lip and palate transmembrane protein 1 (Clptm1). Clptm1 interacted with all GABAAR subunits tested and promoted GABAAR trapping in the endoplasmic reticulum. Overexpression of Clptm1 reduced GABAAR-mediated currents in a recombinant system, in cultured hippocampal neurons, and in brain, with no effect on glycine or AMPA receptor-mediated currents. Conversely, knockdown of Clptm1 increased phasic and tonic inhibitory transmission with no effect on excitatory synaptic transmission. Furthermore, altering the expression level of Clptm1 mimicked activity-induced inhibitory synaptic scaling. Thus, in complement to other GABAAR-associated proteins that promote receptor surface expression, Clptm1 limits GABAAR forward trafficking and regulates inhibitory homeostatic plasticity.
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Affiliation(s)
- Yuan Ge
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Yunhee Kang
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Robert M Cassidy
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Renate Lewis
- Department of Anatomy and Neurobiology, Washington University, St. Louis, MO 63110, USA
| | - Rachel O L Wong
- Department of Biological Structure, University of Washington, Seattle, WA 98195, USA
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology and Michael Smith Laboratories, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Ann Marie Craig
- Djavad Mowafaghian Centre for Brain Health and Department of Psychiatry, University of British Columbia, Vancouver, BC V6T 2B5, Canada.
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82
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Chowdhury D, Turner M, Patriarchi T, Hergarden AC, Anderson D, Zhang Y, Sun J, Chen CY, Ames JB, Hell JW. Ca 2+/calmodulin binding to PSD-95 mediates homeostatic synaptic scaling down. EMBO J 2017; 37:122-138. [PMID: 29118000 DOI: 10.15252/embj.201695829] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 09/07/2017] [Accepted: 10/02/2017] [Indexed: 11/09/2022] Open
Abstract
Postsynaptic density protein-95 (PSD-95) localizes AMPA-type glutamate receptors (AMPARs) to postsynaptic sites of glutamatergic synapses. Its postsynaptic displacement is necessary for loss of AMPARs during homeostatic scaling down of synapses. Here, we demonstrate that upon Ca2+ influx, Ca2+/calmodulin (Ca2+/CaM) binding to the N-terminus of PSD-95 mediates postsynaptic loss of PSD-95 and AMPARs during homeostatic scaling down. Our NMR structural analysis identified E17 within the PSD-95 N-terminus as important for binding to Ca2+/CaM by interacting with R126 on CaM. Mutating E17 to R prevented homeostatic scaling down in primary hippocampal neurons, which is rescued via charge inversion by ectopic expression of CaMR126E, as determined by analysis of miniature excitatory postsynaptic currents. Accordingly, increased binding of Ca2+/CaM to PSD-95 induced by a chronic increase in Ca2+ influx is a critical molecular event in homeostatic downscaling of glutamatergic synaptic transmission.
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Affiliation(s)
| | - Matthew Turner
- Department of Chemistry, University of California, Davis, CA, USA
| | | | - Anne C Hergarden
- Department of Pharmacology, University of California, Davis, CA, USA
| | - David Anderson
- Department of Chemistry, University of California, Davis, CA, USA
| | - Yonghong Zhang
- Department of Chemistry, University of Texas, Edinburgh, TX, USA
| | - Junqing Sun
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Chao-Yin Chen
- Department of Pharmacology, University of California, Davis, CA, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, CA, USA
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, CA, USA
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83
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Puentes-Mestril C, Aton SJ. Linking Network Activity to Synaptic Plasticity during Sleep: Hypotheses and Recent Data. Front Neural Circuits 2017; 11:61. [PMID: 28932187 PMCID: PMC5592216 DOI: 10.3389/fncir.2017.00061] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 08/23/2017] [Indexed: 12/22/2022] Open
Abstract
Research findings over the past two decades have supported a link between sleep states and synaptic plasticity. Numerous mechanistic hypotheses have been put forth to explain this relationship. For example, multiple studies have shown structural alterations to synapses (including changes in synaptic volume, spine density, and receptor composition) indicative of synaptic weakening after a period of sleep. Direct measures of neuronal activity and synaptic strength support the idea that a period of sleep can reduce synaptic strength. This has led to the synaptic homeostasis hypothesis (SHY), which asserts that during slow wave sleep, synapses are downscaled throughout the brain to counteract net strengthening of network synapses during waking experience (e.g., during learning). However, neither the cellular mechanisms mediating these synaptic changes, nor the sleep-dependent activity changes driving those cellular events are well-defined. Here we discuss potential cellular and network dynamic mechanisms which could underlie reductions in synaptic strength during sleep. We also discuss recent findings demonstrating circuit-specific synaptic strengthening (rather than weakening) during sleep. Based on these data, we explore the hypothetical role of sleep-associated network activity patterns in driving synaptic strengthening. We propose an alternative to SHY—namely that depending on experience during prior wake, a variety of plasticity mechanisms may operate in the brain during sleep. We conclude that either synaptic strengthening or synaptic weakening can occur across sleep, depending on changes to specific neural circuits (such as gene expression and protein translation) induced by experiences in wake. Clarifying the mechanisms underlying these different forms of sleep-dependent plasticity will significantly advance our understanding of how sleep benefits various cognitive functions.
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Affiliation(s)
- Carlos Puentes-Mestril
- Neuroscience Graduate Program, Department of Molecular, Cellular, and Developmental Biology, University of MichiganAnn Arbor, MI, United States
| | - Sara J Aton
- Neuroscience Graduate Program, Department of Molecular, Cellular, and Developmental Biology, University of MichiganAnn Arbor, MI, United States
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84
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Baertsch NA, Baker TL. Intermittent apnea elicits inactivity-induced phrenic motor facilitation via a retinoic acid- and protein synthesis-dependent pathway. J Neurophysiol 2017; 118:2702-2710. [PMID: 28814632 DOI: 10.1152/jn.00212.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 08/10/2017] [Accepted: 08/16/2017] [Indexed: 12/13/2022] Open
Abstract
Respiratory motoneuron pools must provide rhythmic inspiratory drive that is robust and reliable, yet dynamic enough to respond to respiratory challenges. One form of plasticity that is hypothesized to contribute to motor output stability by sensing and responding to inadequate respiratory neural activity is inactivity-induced phrenic motor facilitation (iPMF), an increase in inspiratory output triggered by a reduction in phrenic synaptic inputs. Evidence suggests that mechanisms giving rise to iPMF differ depending on the pattern of reduced respiratory neural activity (i.e., neural apnea). A prolonged neural apnea elicits iPMF via a spinal TNF-α-induced increase in atypical PKC activity, but little is known regarding mechanisms that elicit iPMF following intermittent neural apnea. We tested the hypothesis that iPMF triggered by intermittent neural apnea requires retinoic acid and protein synthesis. Phrenic nerve activity was recorded in urethane-anesthetized and -ventilated rats treated intrathecally with an inhibitor of retinoic acid synthesis (4-diethlyaminobenzaldehyde, DEAB), a protein synthesis inhibitor (emetine), or vehicle (artificial cerebrospinal fluid) before intermittent (5 episodes, ~1.25 min each) or prolonged (30 min) neural apnea. Both DEAB and emetine abolished iPMF elicited by intermittent neural apnea but had no effect on iPMF elicited by a prolonged neural apnea. Thus different patterns of reduced respiratory neural activity elicit phenotypically similar iPMF via distinct spinal mechanisms. Understanding mechanisms that allow respiratory motoneurons to dynamically tune their output may have important implications in the context of respiratory control disorders that involve varied patterns of reduced respiratory neural activity, such as central sleep apnea and spinal cord injury.NEW & NOTEWORTHY We identify spinal retinoic acid and protein synthesis as critical components in the cellular cascade whereby repetitive reductions in respiratory neural activity elicit rebound increases in phrenic inspiratory activity.
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Affiliation(s)
- Nathan A Baertsch
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
| | - Tracy L Baker
- Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, Wisconsin
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85
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Schaefer N, Rotermund C, Blumrich EM, Lourenco MV, Joshi P, Hegemann RU, Jamwal S, Ali N, García Romero EM, Sharma S, Ghosh S, Sinha JK, Loke H, Jain V, Lepeta K, Salamian A, Sharma M, Golpich M, Nawrotek K, Paidi RK, Shahidzadeh SM, Piermartiri T, Amini E, Pastor V, Wilson Y, Adeniyi PA, Datusalia AK, Vafadari B, Saini V, Suárez-Pozos E, Kushwah N, Fontanet P, Turner AJ. The malleable brain: plasticity of neural circuits and behavior - a review from students to students. J Neurochem 2017. [PMID: 28632905 DOI: 10.1111/jnc.14107] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
One of the most intriguing features of the brain is its ability to be malleable, allowing it to adapt continually to changes in the environment. Specific neuronal activity patterns drive long-lasting increases or decreases in the strength of synaptic connections, referred to as long-term potentiation and long-term depression, respectively. Such phenomena have been described in a variety of model organisms, which are used to study molecular, structural, and functional aspects of synaptic plasticity. This review originated from the first International Society for Neurochemistry (ISN) and Journal of Neurochemistry (JNC) Flagship School held in Alpbach, Austria (Sep 2016), and will use its curriculum and discussions as a framework to review some of the current knowledge in the field of synaptic plasticity. First, we describe the role of plasticity during development and the persistent changes of neural circuitry occurring when sensory input is altered during critical developmental stages. We then outline the signaling cascades resulting in the synthesis of new plasticity-related proteins, which ultimately enable sustained changes in synaptic strength. Going beyond the traditional understanding of synaptic plasticity conceptualized by long-term potentiation and long-term depression, we discuss system-wide modifications and recently unveiled homeostatic mechanisms, such as synaptic scaling. Finally, we describe the neural circuits and synaptic plasticity mechanisms driving associative memory and motor learning. Evidence summarized in this review provides a current view of synaptic plasticity in its various forms, offers new insights into the underlying mechanisms and behavioral relevance, and provides directions for future research in the field of synaptic plasticity. Read the Editorial Highlight for this article on page 788. Cover Image for this issue: doi: 10.1111/jnc.13815.
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Affiliation(s)
- Natascha Schaefer
- Institute for Clinical Neurobiology, Julius-Maximilians-University of Wuerzburg, Würzburg, Germany
| | - Carola Rotermund
- German Center of Neurodegenerative Diseases, University of Tuebingen, Tuebingen, Germany
| | - Eva-Maria Blumrich
- Centre for Biomolecular Interactions Bremen, Faculty 2 (Biology/Chemistry), University of Bremen, Bremen, Germany.,Centre for Environmental Research and Sustainable Technology, University of Bremen, Bremen, Germany
| | - Mychael V Lourenco
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Pooja Joshi
- Inserm UMR 1141, Robert Debre Hospital, Paris, France
| | - Regina U Hegemann
- Department of Psychology, Brain Health Research Centre, University of Otago, Dunedin, New Zealand
| | - Sumit Jamwal
- Department of Pharmacology, ISF College of Pharmacy, Moga, Punjab, India
| | - Nilufar Ali
- Department of Neuroscience and Regenerative Medicine, Medical College of Georgia, Augusta University, Augusta, Georgia, USA
| | | | - Sorabh Sharma
- Neuropharmacology Division, Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Rajasthan, India
| | - Shampa Ghosh
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Jitendra K Sinha
- National Institute of Nutrition (NIN), Indian Council of Medical Research (ICMR), Tarnaka, Hyderabad, India
| | - Hannah Loke
- Hudson Institute of Medical Research, Melbourne, Victoria, Australia.,Department of Molecular and Translational Science, Monash University, Melbourne, Victoria, Australia
| | - Vishal Jain
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Katarzyna Lepeta
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Ahmad Salamian
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Mahima Sharma
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mojtaba Golpich
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Katarzyna Nawrotek
- Department of Process Thermodynamics, Faculty of Process and Environmental Engineering, Lodz University of Technology, Lodz, Poland
| | - Ramesh K Paidi
- CSIR-Indian Institute of Chemical Biology, Jadavpur, Kolkata, India
| | - Sheila M Shahidzadeh
- Department of Biology, Program in Neuroscience, Syracuse University, Syracuse, New York, USA
| | - Tetsade Piermartiri
- Programa de Pós-Graduação em Neurociências, Universidade Federal de Santa Catarina (UFSC), Florianópolis, Brazil
| | - Elham Amini
- Department of Medicine, University Kebangsaan Malaysia Medical Centre (HUKM), Cheras, Kuala Lumpur, Malaysia
| | - Veronica Pastor
- Instituto de Biología Celular y Neurociencia Prof. Eduardo De Robertis, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Yvette Wilson
- Department of Anatomy and Neuroscience, University of Melbourne, Melbourne, Victoria, Australia
| | - Philip A Adeniyi
- Cell Biology and Neurotoxicity Unit, Department of Anatomy, College of Medicine and Health Sciences, Afe Babalola University, Ado - Ekiti, Ekiti State, Nigeria
| | | | - Benham Vafadari
- Department of Molecular and Cellular Neurobiology, Nencki Institute of Experimental Biology, Polish Academy of Sciences, Warsaw, Poland
| | - Vedangana Saini
- Department of Developmental Neuroscience, Munroe-Meyer Institute, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Edna Suárez-Pozos
- Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, Toxicología, México
| | - Neetu Kushwah
- Defence Institute of Physiology and Allied Sciences, Delhi, India
| | - Paula Fontanet
- Division of Molecular and Cellular Neuroscience, Institute of Cellular Biology and Neuroscience (IBCN), CONICET-UBA, School of Medicine, Buenos Aires, Argentina
| | - Anthony J Turner
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
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86
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Speranza L, Labus J, Volpicelli F, Guseva D, Lacivita E, Leopoldo M, Bellenchi GC, di Porzio U, Bijata M, Perrone-Capano C, Ponimaskin E. Serotonin 5-HT7 receptor increases the density of dendritic spines and facilitates synaptogenesis in forebrain neurons. J Neurochem 2017; 141:647-661. [DOI: 10.1111/jnc.13962] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 01/13/2017] [Accepted: 01/14/2017] [Indexed: 12/21/2022]
Affiliation(s)
- Luisa Speranza
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”; CNR; Naples Italy
- Cellular Neurophysiology; Hannover Medical School; Hannover Germany
- Dominick P. Purpura; Department of Neuroscience Albert Einstein College of Medicine; New York New York USA
| | - Josephine Labus
- Cellular Neurophysiology; Hannover Medical School; Hannover Germany
| | | | - Daria Guseva
- Cellular Neurophysiology; Hannover Medical School; Hannover Germany
| | - Enza Lacivita
- Department of Pharmacy; University of Bari “A. Moro”; Bari Italy
| | | | - Gian Carlo Bellenchi
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”; CNR; Naples Italy
- IRCCS Neuromed; Pozzilli (IS) Italy
| | - Umberto di Porzio
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”; CNR; Naples Italy
| | - Monika Bijata
- Cellular Neurophysiology; Hannover Medical School; Hannover Germany
- Department of Molecular and Cellular Neurobiology; Nencki Institute; Warsaw Poland
| | - Carla Perrone-Capano
- Institute of Genetics and Biophysics “Adriano Buzzati Traverso”; CNR; Naples Italy
- University of Naples Federico II; Naples Italy
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87
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Edelmann E, Cepeda-Prado E, Leßmann V. Coexistence of Multiple Types of Synaptic Plasticity in Individual Hippocampal CA1 Pyramidal Neurons. Front Synaptic Neurosci 2017; 9:7. [PMID: 28352224 PMCID: PMC5348504 DOI: 10.3389/fnsyn.2017.00007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/20/2017] [Indexed: 02/05/2023] Open
Abstract
Understanding learning and memory mechanisms is an important goal in neuroscience. To gain insights into the underlying cellular mechanisms for memory formation, synaptic plasticity processes are studied with various techniques in different brain regions. A valid model to scrutinize different ways to enhance or decrease synaptic transmission is recording of long-term potentiation (LTP) or long-term depression (LTD). At the single cell level, spike timing-dependent plasticity (STDP) protocols have emerged as a powerful tool to investigate synaptic plasticity with stimulation paradigms that also likely occur during memory formation in vivo. Such kind of plasticity can be induced by different STDP paradigms with multiple repeat numbers and stimulation patterns. They subsequently recruit or activate different molecular pathways and neuromodulators for induction and expression of STDP. Dopamine (DA) and brain-derived neurotrophic factor (BDNF) have been recently shown to be important modulators for hippocampal STDP at Schaffer collateral (SC)-CA1 synapses and are activated exclusively by distinguishable STDP paradigms. Distinct types of parallel synaptic plasticity in a given neuron depend on specific subcellular molecular prerequisites. Since the basal and apical dendrites of CA1 pyramidal neurons are known to be heterogeneous, and distance-dependent dendritic gradients for specific receptors and ion channels are described, the dendrites might provide domain specific locations for multiple types of synaptic plasticity in the same neuron. In addition to the distinct signaling and expression mechanisms of various types of LTP and LTD, activation of these different types of plasticity might depend on background brain activity states. In this article, we will discuss some ideas why multiple forms of synaptic plasticity can simultaneously and independently coexist and can contribute so effectively to increasing the efficacy of memory storage and processing capacity of the brain. We hypothesize that resolving the subcellular location of t-LTP and t-LTD mechanisms that are regulated by distinct neuromodulator systems will be essential to reach a more cohesive understanding of synaptic plasticity in memory formation.
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Affiliation(s)
- Elke Edelmann
- Institute of Physiology, Otto-von-Guericke UniversityMagdeburg, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke UniversityMagdeburg, Germany
| | | | - Volkmar Leßmann
- Institute of Physiology, Otto-von-Guericke UniversityMagdeburg, Germany; Center for Behavioral Brain Sciences, Otto-von-Guericke UniversityMagdeburg, Germany
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88
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Malerba P, Straudi S, Fregni F, Bazhenov M, Basaglia N. Using Biophysical Models to Understand the Effect of tDCS on Neurorehabilitation: Searching for Optimal Covariates to Enhance Poststroke Recovery. Front Neurol 2017; 8:58. [PMID: 28280482 PMCID: PMC5322214 DOI: 10.3389/fneur.2017.00058] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 02/09/2017] [Indexed: 12/27/2022] Open
Abstract
Stroke is a leading cause of worldwide disability, and up to 75% of survivors suffer from some degree of arm paresis. Recently, rehabilitation of stroke patients has focused on recovering motor skills by taking advantage of use-dependent neuroplasticity, where high-repetition of goal-oriented movement is at times combined with non-invasive brain stimulation, such as transcranial direct current stimulation (tDCS). Merging the two approaches is thought to provide outlasting clinical gains, by enhancing synaptic plasticity and motor relearning in the motor cortex primary area. However, this general approach has shown mixed results across the stroke population. In particular, stroke location has been found to correlate with the likelihood of success, which suggests that different patients might require different protocols. Understanding how motor rehabilitation and stimulation interact with ongoing neural dynamics is crucial to optimize rehabilitation strategies, but it requires theoretical and computational models to consider the multiple levels at which this complex phenomenon operate. In this work, we argue that biophysical models of cortical dynamics are uniquely suited to address this problem. Specifically, biophysical models can predict treatment efficacy by introducing explicit variables and dynamics for damaged connections, changes in neural excitability, neurotransmitters, neuromodulators, plasticity mechanisms, and repetitive movement, which together can represent brain state, effect of incoming stimulus, and movement-induced activity. In this work, we hypothesize that effects of tDCS depend on ongoing neural activity and that tDCS effects on plasticity may be also related to enhancing inhibitory processes. We propose a model design for each step of this complex system, and highlight strengths and limitations of the different modeling choices within our approach. Our theoretical framework proposes a change in paradigm, where biophysical models can contribute to the future design of novel protocols, in which combined tDCS and motor rehabilitation strategies are tailored to the ongoing dynamics that they interact with, by considering the known biophysical factors recruited by such protocols and their interaction.
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Affiliation(s)
- Paola Malerba
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sofia Straudi
- Neuroscience and Rehabilitation Department, Ferrara University Hospital, Ferrara, Italy
| | - Felipe Fregni
- Center of Neuromodulation, Spaulding Rehabilitation Hospital, Harvard Medical School, Boston, MA, USA
| | - Maxim Bazhenov
- Department of Medicine, University of California San Diego, La Jolla, CA, USA
| | - Nino Basaglia
- Neuroscience and Rehabilitation Department, Ferrara University Hospital, Ferrara, Italy
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89
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Zinc in the Monoaminergic Theory of Depression: Its Relationship to Neural Plasticity. Neural Plast 2017; 2017:3682752. [PMID: 28299207 PMCID: PMC5337390 DOI: 10.1155/2017/3682752] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 01/24/2017] [Indexed: 12/21/2022] Open
Abstract
Preclinical and clinical studies have demonstrated that zinc possesses antidepressant properties and that it may augment the therapy with conventional, that is, monoamine-based, antidepressants. In this review we aim to discuss the role of zinc in the pathophysiology and treatment of depression with regard to the monoamine hypothesis of the disease. Particular attention will be paid to the recently described zinc-sensing GPR39 receptor as well as aspects of zinc deficiency. Furthermore, an attempt will be made to give a possible explanation of the mechanisms by which zinc interacts with the monoamine system in the context of depression and neural plasticity.
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90
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Schaukowitch K, Reese AL, Kim SK, Kilaru G, Joo JY, Kavalali ET, Kim TK. An Intrinsic Transcriptional Program Underlying Synaptic Scaling during Activity Suppression. Cell Rep 2017; 18:1512-1526. [PMID: 28178527 PMCID: PMC5524384 DOI: 10.1016/j.celrep.2017.01.033] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 11/15/2016] [Accepted: 01/14/2017] [Indexed: 11/15/2022] Open
Abstract
Homeostatic scaling allows neurons to maintain stable activity patterns by globally altering their synaptic strength in response to changing activity levels. Suppression of activity by the blocking of action potentials increases synaptic strength through an upregulation of surface α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors. Although this synaptic upscaling was shown to require transcription, the molecular nature of the intrinsic transcription program underlying this process and its functional significance have been unclear. Using RNA-seq, we identified 73 genes that were specifically upregulated in response to activity suppression. In particular, Neuronal pentraxin-1 (Nptx1) increased within 6 hr of activity blockade, and knockdown of this gene blocked the increase in synaptic strength. Nptx1 induction is mediated by calcium influx through the T-type voltage-gated calcium channel, as well as two transcription factors, SRF and ELK1. Altogether, these results uncover a transcriptional program that specifically operates when neuronal activity is suppressed to globally coordinate the increase in synaptic strength.
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Affiliation(s)
- Katie Schaukowitch
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Austin L Reese
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Seung-Kyoon Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Gokhul Kilaru
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Jae-Yeol Joo
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Ege T Kavalali
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA
| | - Tae-Kyung Kim
- Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
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91
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Frank MG. Sleep and plasticity in the visual cortex: more than meets the eye. Curr Opin Neurobiol 2017; 44:8-12. [PMID: 28126451 DOI: 10.1016/j.conb.2017.01.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 01/04/2017] [Indexed: 12/26/2022]
Abstract
The visual cortex has provided key insights into how experience shapes cortical circuitry. Scientists have identified how different manipulations of visual experience trigger distinct forms of plasticity as well as many of the underlying cellular and molecular mechanisms. Intriguingly, experience is not the only factor driving plasticity in the visual system. Sleep is also required for the full expression of plasticity in the developing visual cortex. In this review, I discuss what we have learned about the role of sleep in visual cortical plasticity and what it tells us about sleep function.
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Affiliation(s)
- Marcos G Frank
- Department of Biomedical Sciences, Elson S. Floyd College of Medicine, Washington State University Spokane,Pharmaceutical and Biomedical Science Building 213, 412 E. Spokane Falls Blvd., Spokane, WA 99202, USA.
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92
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Werner CT, Murray CH, Reimers JM, Chauhan NM, Woo KKY, Molla HM, Loweth JA, Wolf ME. Trafficking of calcium-permeable and calcium-impermeable AMPA receptors in nucleus accumbens medium spiny neurons co-cultured with prefrontal cortex neurons. Neuropharmacology 2016; 116:224-232. [PMID: 27993521 DOI: 10.1016/j.neuropharm.2016.12.014] [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: 09/17/2016] [Revised: 12/09/2016] [Accepted: 12/15/2016] [Indexed: 11/27/2022]
Abstract
AMPA receptor (AMPAR) transmission onto medium spiny neurons (MSNs) of the adult rat nucleus accumbens (NAc) is normally dominated by GluA2-containing, Ca2+-impermeable AMPAR (CI-AMPARs). However, GluA2-lacking, Ca2+-permeable AMPA receptors (CP-AMPARs) accumulate after prolonged withdrawal from extended-access cocaine self-administration and thereafter their activation is required for the intensified (incubated) cue-induced cocaine craving that characterizes prolonged withdrawal from such regimens. These findings suggest the existence of mechanisms in NAc MSNs that differentially regulate CI-AMPARs and CP-AMPARs. Here, we compared trafficking of GluA1A2 CI-AMPARs and homomeric GluA1 CP-AMPARs using immunocytochemical assays in cultured NAc MSNs plated with prefrontal cortical neurons to restore excitatory inputs. We began by evaluating constitutive internalization of surface receptors and found that this occurs more rapidly for CP-AMPARs. Next, we studied receptor insertion into the membrane; combined with past results, the present findings suggest that activation of protein kinase A accelerates insertion of both CP-AMPARs and CI-AMPARs. We also studied constitutive cycling (net loss of receptors from the membrane under conditions where internalization and recycling are both occurring). Interestingly, although CP-AMPARs exhibit faster constitutive internalization, they cycle at similar rates as CI-AMPARs, suggesting faster reinsertion of CP-AMPARs. In studies of synaptic scaling, long-term (24 h) activity blockade increased surface expression and cycling rates of CI-AMPARs but not CP-AMPARs, whereas long-term increases in activity produced more pronounced scaling down of CI-AMPARs than CP-AMPARs but did not alter receptor cycling. These findings can be used to evaluate and generate hypotheses regarding AMPAR plasticity in the rat NAc following cocaine exposure.
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Affiliation(s)
- Craig T Werner
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Conor H Murray
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Jeremy M Reimers
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Niravkumar M Chauhan
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Kenneth K Y Woo
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Hanna M Molla
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Jessica A Loweth
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA
| | - Marina E Wolf
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL 60064, USA.
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93
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Duarte CB, Carvalho AL. 7 th ISN special neurochemistry conference 'Synaptic function and dysfunction in brain diseases'. J Neurochem 2016; 139:918-920. [PMID: 27859239 DOI: 10.1111/jnc.13839] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Revised: 10/27/2016] [Accepted: 08/26/2016] [Indexed: 01/03/2023]
Abstract
This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
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Affiliation(s)
- Carlos B Duarte
- CNC-Center for Neuroscience and Cell Biology and Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Ana Luisa Carvalho
- CNC-Center for Neuroscience and Cell Biology and Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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94
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Braegelmann KM, Streeter KA, Fields DP, Baker TL. Plasticity in respiratory motor neurons in response to reduced synaptic inputs: A form of homeostatic plasticity in respiratory control? Exp Neurol 2016; 287:225-234. [PMID: 27456270 DOI: 10.1016/j.expneurol.2016.07.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2016] [Revised: 06/16/2016] [Accepted: 07/20/2016] [Indexed: 12/31/2022]
Abstract
For most individuals, the respiratory control system produces a remarkably stable and coordinated motor output-recognizable as a breath-from birth until death. Very little is understood regarding the processes by which the respiratory control system maintains network stability in the presence of changing physiological demands and network properties that occur throughout life. An emerging principle of neuroscience is that neural activity is sensed and adjusted locally to assure that neurons continue to operate in an optimal range, yet to date, it is unknown whether such homeostatic plasticity is a feature of the neurons controlling breathing. Here, we review the evidence that local mechanisms sense and respond to perturbations in respiratory neural activity, with a focus on plasticity in respiratory motor neurons. We discuss whether these forms of plasticity represent homeostatic plasticity in respiratory control. We present new analyses demonstrating that reductions in synaptic inputs to phrenic motor neurons elicit a compensatory enhancement of phrenic inspiratory motor output, a form of plasticity termed inactivity-induced phrenic motor facilitation (iPMF), that is proportional to the magnitude of activity deprivation. Although the physiological role of iPMF is not understood, we hypothesize that it has an important role in protecting the drive to breathe during conditions of prolonged or intermittent reductions in respiratory neural activity, such as following spinal cord injury or during central sleep apnea.
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Affiliation(s)
- K M Braegelmann
- Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, United States
| | - K A Streeter
- Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, United States
| | - D P Fields
- Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, United States
| | - T L Baker
- Department of Comparative Biosciences, University of Wisconsin-Madison, 2015 Linden Drive, Madison, WI 53706, United States.
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