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Xu M, Liu F, Hu Y, Li H, Wei Y, Zhong S, Pei J, Deng L. Adaptive Synaptic Scaling in Spiking Networks for Continual Learning and Enhanced Robustness. IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS 2025; 36:5151-5165. [PMID: 38536699 DOI: 10.1109/tnnls.2024.3373599] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/06/2025]
Abstract
Synaptic plasticity plays a critical role in the expression power of brain neural networks. Among diverse plasticity rules, synaptic scaling presents indispensable effects on homeostasis maintenance and synaptic strength regulation. In the current modeling of brain-inspired spiking neural networks (SNN), backpropagation through time is widely adopted because it can achieve high performance using a small number of time steps. Nevertheless, the synaptic scaling mechanism has not yet been well touched. In this work, we propose an experience-dependent adaptive synaptic scaling mechanism (AS-SNN) for spiking neural networks. The learning process has two stages: First, in the forward path, adaptive short-term potentiation or depression is triggered for each synapse according to afferent stimuli intensity accumulated by presynaptic historical neural activities. Second, in the backward path, long-term consolidation is executed through gradient signals regulated by the corresponding scaling factor. This mechanism shapes the pattern selectivity of synapses and the information transfer they mediate. We theoretically prove that the proposed adaptive synaptic scaling function follows a contraction map and finally converges to an expected fixed point, in accordance with state-of-the-art results in three tasks on perturbation resistance, continual learning, and graph learning. Specifically, for the perturbation resistance and continual learning tasks, our approach improves the accuracy on the N-MNIST benchmark over the baseline by 44% and 25%, respectively. An expected firing rate callback and sparse coding can be observed in graph learning. Extensive experiments on ablation study and cost evaluation evidence the effectiveness and efficiency of our nonparametric adaptive scaling method, which demonstrates the great potential of SNN in continual learning and robust learning.
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2
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Nielsen AC, Anderson CL, Ens C, Boyce AKJ, Thompson RJ. Non-ionotropic NMDAR signalling activates Panx1 to induce P2X4R-dependent long-term depression in the hippocampus. J Physiol 2024. [PMID: 39709529 DOI: 10.1113/jp285193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Accepted: 11/28/2024] [Indexed: 12/23/2024] Open
Abstract
In recent years, evidence supporting non-ionotropic signalling by the NMDA receptor (niNMDAR) has emerged, including roles in long-term depression (LTD). Here, we investigated whether niNMDAR-pannexin-1 (Panx1) contributes to LTD at the CA3-CA1 hippocampal synapse. Using whole-cell, patch clamp electrophysiology in rat hippocampal slices, we show that a low-frequency stimulation (3 Hz) of the Schaffer collaterals produces LTD that is blocked by continuous but not transient application of the NMDAR competitive antagonist, MK-801. After transient MK-801, LTD involved pannexin-1 and sarcoma (Src) kinase. We show that pannexin-1 is not permeable to Ca2+, but probably releases ATP to induce LTD via P2X4 purinergic receptors because LTD after transient MK-801 application was prevented by 5-BDBD. Thus, we conclude that niNMDAR activation of Panx1 can link glutamatergic and purinergic pathways to produce LTD following low frequency synaptic stimulation when NMDARs are transiently inhibited. KEY POINTS: Differential effect of short-term D-APV and MK-801 application on long-term depression (LTD) suggests that the NMDA receptor (niNMDAR) contributes to later phases of synaptic depression. niNMDAR LTD involved sarcoma (Src) kinase and pannexin-1 (Panx1), which is a pathway previously identified to be active during excitotoxicity. Panx1 was not calcium permeable but may contribute to late phase LTD via ATP release. Panx1 blockers prevent LTD, and this was rescued with exogenous ATP application. Inhibition of LTD with 5-BDBD suggests the downstream involvement of postsynaptic P2X4 receptors.
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Affiliation(s)
- Allison C Nielsen
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Connor L Anderson
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Carina Ens
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Andrew K J Boyce
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Roger J Thompson
- Department of Cell Biology & Anatomy, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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3
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Weir JS, Hanssen KS, Winter-Hjelm N, Sandvig A, Sandvig I. Evolving alterations of structural organization and functional connectivity in feedforward neural networks after induced P301L tau mutation. Eur J Neurosci 2024; 60:7228-7248. [PMID: 39622242 DOI: 10.1111/ejn.16625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 10/29/2024] [Accepted: 11/15/2024] [Indexed: 12/17/2024]
Abstract
Reciprocal structure-function relationships underlie both healthy and pathological behaviours in complex neural networks. Thus, understanding neuropathology and network dysfunction requires a thorough investigation of the complex interactions between structural and functional network reconfigurations in response to perturbation. Such adaptations are often difficult to study in vivo. For example, subtle, evolving changes in synaptic connectivity, transmission and the electrophysiological shift from healthy to pathological states, for example alterations that may be associated with evolving neurodegenerative disease, such as Alzheimer's, are difficult to study in the brain. Engineered in vitro neural networks are powerful models that enable selective targeting, manipulation and monitoring of dynamic neural network behaviour at the micro- and mesoscale in physiological and pathological conditions. In this study, we engineered feedforward cortical neural networks using two-nodal microfluidic devices with controllable connectivity interfaced with microelectrode arrays (mMEAs). We induced P301L mutated tau protein to the presynaptic node of these networks and monitored network dynamics over three weeks. Induced perturbation resulted in altered structural organization and extensive axonal retraction starting in the perturbed node. Perturbed networks also exhibited functional changes in intranodal activity, which manifested as an overall decline in both firing rate and bursting activity, with a progressive increase in synchrony over time and a decrease in internodal signal propagation between pre- and post-synaptic nodes. These results provide insights into dynamic structural and functional reconfigurations at the micro- and mesoscale as a result of evolving pathology and illustrate the utility of engineered networks as models of network function and dysfunction.
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Affiliation(s)
- Janelle S Weir
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Katrine Sjaastad Hanssen
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Nicolai Winter-Hjelm
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Axel Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
- Department of Community Medicine and Rehabilitation, Umeå University, Umeå, Sweden
- Department of Neurorehabilitation, Umeå University Hospital, Umeå, Sweden
| | - Ioanna Sandvig
- Department of Neuromedicine and Movement Science, Faculty of Medicine and Health Sciences, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
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4
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Wen W, Turrigiano GG. Keeping Your Brain in Balance: Homeostatic Regulation of Network Function. Annu Rev Neurosci 2024; 47:41-61. [PMID: 38382543 DOI: 10.1146/annurev-neuro-092523-110001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
To perform computations with the efficiency necessary for animal survival, neocortical microcircuits must be capable of reconfiguring in response to experience, while carefully regulating excitatory and inhibitory connectivity to maintain stable function. This dynamic fine-tuning is accomplished through a rich array of cellular homeostatic plasticity mechanisms that stabilize important cellular and network features such as firing rates, information flow, and sensory tuning properties. Further, these functional network properties can be stabilized by different forms of homeostatic plasticity, including mechanisms that target excitatory or inhibitory synapses, or that regulate intrinsic neuronal excitability. Here we discuss which aspects of neocortical circuit function are under homeostatic control, how this homeostasis is realized on the cellular and molecular levels, and the pathological consequences when circuit homeostasis is impaired. A remaining challenge is to elucidate how these diverse homeostatic mechanisms cooperate within complex circuits to enable them to be both flexible and stable.
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Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
| | - Gina G Turrigiano
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
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Kim H, Woo SY, Kim H. Neuron Circuit Based on a Split-gate Transistor with Nonvolatile Memory for Homeostatic Functions of Biological Neurons. Biomimetics (Basel) 2024; 9:335. [PMID: 38921215 PMCID: PMC11201417 DOI: 10.3390/biomimetics9060335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2024] [Revised: 05/24/2024] [Accepted: 05/30/2024] [Indexed: 06/27/2024] Open
Abstract
To mimic the homeostatic functionality of biological neurons, a split-gate field-effect transistor (S-G FET) with a charge trap layer is proposed within a neuron circuit. By adjusting the number of charges trapped in the Si3N4 layer, the threshold voltage (Vth) of the S-G FET changes. To prevent degradation of the gate dielectric due to program/erase pulses, the gates for read operation and Vth control were separated through the fin structure. A circuit that modulates the width and amplitude of the pulse was constructed to generate a Program/Erase pulse for the S-G FET as the output pulse of the neuron circuit. By adjusting the Vth of the neuron circuit, the firing rate can be lowered by increasing the Vth of the neuron circuit with a high firing rate. To verify the performance of the neural network based on S-G FET, a simulation of online unsupervised learning and classification in a 2-layer SNN is performed. The results show that the recognition rate was improved by 8% by increasing the threshold of the neuron circuit fired.
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Affiliation(s)
- Hansol Kim
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Sung Yun Woo
- School of Electronic and Electrical Engineering, Kyungpook National University, Daegu 41566, Republic of Korea;
| | - Hyungjin Kim
- Division of Materials Science and Engineering, Hanyang University, Seoul 04763, Republic of Korea
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Wei M, Yang L, Su F, Liu Y, Zhao X, Luo L, Sun X, Liu S, Dong Z, Zhang Y, Shi YS, Liang J, Zhang C. ABHD6 drives endocytosis of AMPA receptors to regulate synaptic plasticity and learning flexibility. Prog Neurobiol 2024; 233:102559. [PMID: 38159878 DOI: 10.1016/j.pneurobio.2023.102559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 10/26/2023] [Accepted: 12/06/2023] [Indexed: 01/03/2024]
Abstract
Trafficking of α-Amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) receptors (AMPARs), mediated by AMPAR interacting proteins, enabled neurons to maintain tuning capabilities at rest or active state. α/β-Hydrolase domain-containing 6 (ABHD6), an endocannabinoid hydrolase, was an AMPAR auxiliary subunit found to negatively regulate the surface delivery of AMPARs. While ABHD6 was found to prevent AMPAR tetramerization in endoplasmic reticulum, ABHD6 was also reported to localize at postsynaptic site. Yet, the role of ABHD6 interacting with AMPAR at postsynaptic site, and the physiological significance of ABHD6 regulating AMPAR trafficking remains elusive. Here, we generated the ABHD6 knockout (ABHD6KO) mice and found that deletion of ABHD6 selectively enhanced AMPAR-mediated basal synaptic responses and the surface expression of postsynaptic AMPARs. Furthermore, we found that loss of ABHD6 impaired hippocampal long-term depression (LTD) and synaptic downscaling in hippocampal synapses. AMPAR internalization assays revealed that ABHD6 was essential for neuronal activity-dependent endocytosis of surface AMPARs, which is independent of ABHD6's hydrolase activity. The defects of AMPAR endocytosis and LTD are expressed as deficits in learning flexibility in ABHD6KO mice. Collectively, we demonstrated that ABHD6 is an endocytic accessory protein promoting AMPAR endocytosis, thereby contributes to the formation of LTD, synaptic downscaling and reversal learning.
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Affiliation(s)
- Mengping Wei
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
| | - Lei Yang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Feng Su
- Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Ying Liu
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China
| | - Xinyi Zhao
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Lin Luo
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Xinyue Sun
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Sen Liu
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China
| | - Zhaoqi Dong
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China
| | - Yong Zhang
- Department of Neurobiology, School of Basic Medical Sciences and Neuroscience Research Institute, Key Lab for Neuroscience, Ministry of Education of China and National Health Commission of the PR China, IDG/McGovern Institute for Brain Research at PKU, Peking University, Beijing 100083, China
| | - Yun Stone Shi
- Ministry of Education Key Laboratory of Model Animal for Disease Study, Model Animal Research Center, Medical School, Nanjing University, Nanjing 210032, China
| | - Jing Liang
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China; Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China.
| | - Chen Zhang
- School of Basic Medical Sciences, Beijing Key Laboratory of Neural Regeneration and Repair, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing 100069, China; State Key Laboratory of Neurology and Oncology Drug Development, Nanjing 210000, Jiangsu, China; Chinese Institute for Brain Research, Beijing 102206, China.
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7
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Han Y, Goel P, Chen J, Perry S, Tran N, Nishimura S, Sanjani M, Chien C, Dickman D. Excess glutamate release triggers subunit-specific homeostatic receptor scaling. Cell Rep 2023; 42:112775. [PMID: 37436892 PMCID: PMC10529671 DOI: 10.1016/j.celrep.2023.112775] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/06/2023] [Accepted: 06/25/2023] [Indexed: 07/14/2023] Open
Abstract
Ionotropic glutamate receptors (GluRs) are targets for modulation in Hebbian and homeostatic synaptic plasticity and are remodeled by development, experience, and disease. We have probed the impact of synaptic glutamate levels on the two postsynaptic GluR subtypes at the Drosophila neuromuscular junction, GluRA and GluRB. We first demonstrate that GluRA and GluRB compete to establish postsynaptic receptive fields, and that proper GluR abundance and composition can be orchestrated in the absence of any synaptic glutamate release. However, excess glutamate adaptively tunes postsynaptic GluR abundance, echoing GluR scaling observed in mammalian systems. Furthermore, when GluRA vs. GluRB competition is eliminated, GluRB becomes insensitive to glutamate modulation. In contrast, GluRA is now homeostatically regulated by excess glutamate to maintain stable miniature activity, where Ca2+ permeability through GluRA receptors is required. Thus, excess glutamate, GluR competition, and Ca2+ signaling collaborate to selectively target GluR subtypes for homeostatic regulation at postsynaptic compartments.
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Affiliation(s)
- Yifu Han
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Pragya Goel
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Jiawen Chen
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Sarah Perry
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Nancy Tran
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Samantha Nishimura
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Manisha Sanjani
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Chun Chien
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA
| | - Dion Dickman
- Department of Neurobiology, University of Southern California, Los Angeles, CA 90089, USA.
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8
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The times they are a-changin': a proposal on how brain flexibility goes beyond the obvious to include the concepts of "upward" and "downward" to neuroplasticity. Mol Psychiatry 2023; 28:977-992. [PMID: 36575306 PMCID: PMC10005965 DOI: 10.1038/s41380-022-01931-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 12/07/2022] [Accepted: 12/14/2022] [Indexed: 12/28/2022]
Abstract
Since the brain was found to be somehow flexible, plastic, researchers worldwide have been trying to comprehend its fundamentals to better understand the brain itself, make predictions, disentangle the neurobiology of brain diseases, and finally propose up-to-date treatments. Neuroplasticity is simple as a concept, but extremely complex when it comes to its mechanisms. This review aims to bring to light an aspect about neuroplasticity that is often not given enough attention as it should, the fact that the brain's ability to change would include its ability to disconnect synapses. So, neuronal shrinkage, decrease in spine density or dendritic complexity should be included within the concept of neuroplasticity as part of its mechanisms, not as an impairment of it. To that end, we extensively describe a variety of studies involving topics such as neurodevelopment, aging, stress, memory and homeostatic plasticity to highlight how the weakening and disconnection of synapses organically permeate the brain in so many ways as a good practice of its intrinsic physiology. Therefore, we propose to break down neuroplasticity into two sub-concepts, "upward neuroplasticity" for changes related to synaptic construction and "downward neuroplasticity" for changes related to synaptic deconstruction. With these sub-concepts, neuroplasticity could be better understood from a bigger landscape as a vector in which both directions could be taken for the brain to flexibly adapt to certain demands. Such a paradigm shift would allow a better understanding of the concept of neuroplasticity to avoid any data interpretation bias, once it makes clear that there is no morality with regard to the organic and physiological changes that involve dynamic biological systems as seen in the brain.
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Kinoshita PF, Orellana AM, Andreotti DZ, de Souza GA, de Mello NP, de Sá Lima L, Kawamoto EM, Scavone C. Consequences of the Lack of TNFR1 in Ouabain Response in the Hippocampus of C57BL/6J Mice. Biomedicines 2022; 10:biomedicines10112937. [PMID: 36428505 PMCID: PMC9688030 DOI: 10.3390/biomedicines10112937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 10/19/2022] [Accepted: 10/24/2022] [Indexed: 11/17/2022] Open
Abstract
Ouabain is a cardiac glycoside that has a protective effect against neuroinflammation at low doses through Na+/K+-ATPase signaling and that can activate tumor necrosis factor (TNF) in the brain. TNF plays an essential role in neuroinflammation and regulates glutamate receptors by acting on two different receptors (tumor necrosis factor receptor 1 [TNFR1] and TNFR2) that have distinct functions and expression. The activation of constitutively and ubiquitously expressed TNFR1 leads to the expression of pro-inflammatory cytokines. Thus, this study aimed to elucidate the effects of ouabain in a TNFR1 knockout (KO) mouse model. Interestingly, the hippocampus of TNFR1 KO mice showed a basal increase in both TNFR2 membrane expression and brain-derived neurotrophic factor (BDNF) release, suggesting a compensatory mechanism. Moreover, ouabain activated TNF-α-converting enzyme/a disintegrin and metalloprotease 17 (TACE/ADAM17), decreased N-methyl-D-aspartate (NMDA) receptor subunit 2A (NR2A) expression, and induced anxiety-like behavior in both genotype animals, independent of the presence of TNFR1. However, ouabain induced an increase in interleukin (IL)-1β in the hippocampus, a decrease in IL-6 in serum, and an increase in NMDA receptor subunit 1 (NR1) only in wild-type (WT) mice, indicating that TNFR1 or TNFR2 expression may be important for some effects of ouabain. Collectively, our results indicate a connection between ouabain signaling and TNFR1, with the effect of ouabain partially dependent on TNFR1.
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Affiliation(s)
- Paula Fernanda Kinoshita
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Ana Maria Orellana
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Diana Zukas Andreotti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Giovanna Araujo de Souza
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Natalia Prudente de Mello
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Larissa de Sá Lima
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-900, Brazil
- Correspondence:
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10
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Overhoff M, Tellkamp F, Hess S, Tolve M, Tutas J, Faerfers M, Ickert L, Mohammadi M, De Bruyckere E, Kallergi E, Delle Vedove A, Nikoletopoulou V, Wirth B, Isensee J, Hucho T, Puchkov D, Isbrandt D, Krueger M, Kloppenburg P, Kononenko NL. Autophagy regulates neuronal excitability by controlling cAMP/protein kinase A signaling at the synapse. EMBO J 2022; 41:e110963. [PMID: 36217825 PMCID: PMC9670194 DOI: 10.15252/embj.2022110963] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 09/10/2022] [Accepted: 09/14/2022] [Indexed: 01/13/2023] Open
Abstract
Autophagy provides nutrients during starvation and eliminates detrimental cellular components. However, accumulating evidence indicates that autophagy is not merely a housekeeping process. Here, by combining mouse models of neuron-specific ATG5 deficiency in either excitatory or inhibitory neurons with quantitative proteomics, high-content microscopy, and live-imaging approaches, we show that autophagy protein ATG5 functions in neurons to regulate cAMP-dependent protein kinase A (PKA)-mediated phosphorylation of a synapse-confined proteome. This function of ATG5 is independent of bulk turnover of synaptic proteins and requires the targeting of PKA inhibitory R1 subunits to autophagosomes. Neuronal loss of ATG5 causes synaptic accumulation of PKA-R1, which sequesters the PKA catalytic subunit and diminishes cAMP/PKA-dependent phosphorylation of postsynaptic cytoskeletal proteins that mediate AMPAR trafficking. Furthermore, ATG5 deletion in glutamatergic neurons augments AMPAR-dependent excitatory neurotransmission and causes the appearance of spontaneous recurrent seizures in mice. Our findings identify a novel role of autophagy in regulating PKA signaling at glutamatergic synapses and suggest the PKA as a target for restoration of synaptic function in neurodegenerative conditions with autophagy dysfunction.
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Affiliation(s)
- Melina Overhoff
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Frederik Tellkamp
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany
| | - Simon Hess
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of ZoologyUniversity of CologneCologneGermany
| | - Marianna Tolve
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Janine Tutas
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Marcel Faerfers
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Lotte Ickert
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Milad Mohammadi
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Elodie De Bruyckere
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany
| | - Emmanouela Kallergi
- Département des Neurosciences FondamentalesUniversity of LausanneLausanneSwitzerland
| | - Andrea Delle Vedove
- Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | | | - Brunhilde Wirth
- Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany,Institute of Human Genetics, Center for Molecular Medicine Cologne, Center for Rare Diseases Cologne, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Joerg Isensee
- Translational Pain Research, Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Tim Hucho
- Translational Pain Research, Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
| | - Dmytro Puchkov
- Leibniz Institute for Molecular Pharmacology (FMP)BerlinGermany
| | - Dirk Isbrandt
- Institute for Molecular and Behavioral Neuroscience, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany,Experimental NeurophysiologyGerman Center for Neurodegenerative DiseasesBonnGermany
| | - Marcus Krueger
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of GeneticsUniversity of CologneCologneGermany
| | - Peter Kloppenburg
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Faculty of Mathematics and Natural Sciences, Institute of ZoologyUniversity of CologneCologneGermany
| | - Natalia L Kononenko
- Cologne Excellence Cluster Cellular Stress Response in Aging‐Associated Diseases (CECAD)University of CologneCologneGermany,Center for Physiology and Pathophysiology, Faculty of Medicine and University Hospital CologneUniversity of CologneCologneGermany
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11
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Qneibi M, Hawash M, Bdir S, Nacak Baytas S. Targeting the kinetics mechanism of AMPA receptor inhibition by 2-oxo-3H-benzoxazole derivatives. Bioorg Chem 2022; 129:106163. [PMID: 36137313 DOI: 10.1016/j.bioorg.2022.106163] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 09/11/2022] [Accepted: 09/13/2022] [Indexed: 11/02/2022]
Abstract
Ionotropic glutamate receptors are ligand-gated ion channels found in most excitatory synapses in the brain that allow for rapid information transfer. Due to their quick excitatory processes, α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid-type glutamate (AMPA) receptors have been linked to various neurodegenerative disorders, including epilepsy and Parkinson's disease. It has been critical to develop new neuroprotective compounds that inhibit AMPA-sensitive glutamate-controlled channels allosterically, and many classes of AMPA receptor-inhibiting compounds have been synthesized and evaluated. The current study focuses on thirteen 2-oxo-3H-benzoxazole derivatives (COBs) as potential AMPA receptor modulators. The whole-cell patch-clamp technique was used to assess the effects of COBs on AMPA receptor subunits (i.e., GluA1, GluA2, GluA1/2, and GluA2/3) amplitudes in the human embryonic kidney (HEK293) cells and the rates of desensitization and deactivation before and after COBs delivery. According to our findings, the COBs bind AMPA receptors allosterically and alter AMPAR characteristics in various ways. COB-1, COB-2, and COB-13 were the most effective in decreasing AMPAR currents by around 10-12 folds compared to the other COBs. Furthermore, the COBs significantly impacted AMPA receptor deactivation and desensitization rates. Of the examined homomeric and heteromeric AMPAR subunits, GluA2 was the most impacted. COB compounds appear to be a viable candidate for future study and development in regulating neurological diseases involving AMPA receptors.
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Affiliation(s)
- Mohammad Qneibi
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine.
| | - Mohammed Hawash
- Department of Pharmacy, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Sosana Bdir
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, An-Najah National University, Nablus, Palestine
| | - Sultan Nacak Baytas
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Gazi University, Ankara, Turkey
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12
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Yasuda R, Hayashi Y, Hell JW. CaMKII: a central molecular organizer of synaptic plasticity, learning and memory. Nat Rev Neurosci 2022; 23:666-682. [PMID: 36056211 DOI: 10.1038/s41583-022-00624-2] [Citation(s) in RCA: 191] [Impact Index Per Article: 63.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2022] [Indexed: 12/30/2022]
Abstract
Calcium-calmodulin (CaM)-dependent protein kinase II (CaMKII) is the most abundant protein in excitatory synapses and is central to synaptic plasticity, learning and memory. It is activated by intracellular increases in calcium ion levels and triggers molecular processes necessary for synaptic plasticity. CaMKII phosphorylates numerous synaptic proteins, thereby regulating their structure and functions. This leads to molecular events crucial for synaptic plasticity, such as receptor trafficking, localization and activity; actin cytoskeletal dynamics; translation; and even transcription through synapse-nucleus shuttling. Several new tools affording increasingly greater spatiotemporal resolution have revealed the link between CaMKII activity and downstream signalling processes in dendritic spines during synaptic and behavioural plasticity. These technologies have provided insights into the function of CaMKII in learning and memory.
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Affiliation(s)
- Ryohei Yasuda
- Max Planck Florida Institute for Neuroscience, Jupiter, FL, USA.
| | - Yasunori Hayashi
- Department of Pharmacology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
| | - Johannes W Hell
- Department of Pharmacology, University of California, Davis, Davis, CA, USA.
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13
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Liu Z, Jiang M, Liakath-Ali K, Sclip A, Ko J, Zhang RS, Südhof TC. Deletion of Calsyntenin-3, an atypical cadherin, suppresses inhibitory synapses but increases excitatory parallel-fiber synapses in cerebellum. eLife 2022; 11:e70664. [PMID: 35420982 PMCID: PMC9064300 DOI: 10.7554/elife.70664] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 04/14/2022] [Indexed: 01/11/2023] Open
Abstract
Cadherins contribute to the organization of nearly all tissues, but the functions of several evolutionarily conserved cadherins, including those of calsyntenins, remain enigmatic. Puzzlingly, two distinct, non-overlapping functions for calsyntenins were proposed: As postsynaptic neurexin ligands in synapse formation, or as presynaptic kinesin adaptors in vesicular transport. Here, we show that, surprisingly, acute CRISPR-mediated deletion of calsyntenin-3 in mouse cerebellum in vivo causes a large decrease in inhibitory synapse, but a robust increase in excitatory parallel-fiber synapses in Purkinje cells. As a result, inhibitory synaptic transmission was suppressed, whereas parallel-fiber synaptic transmission was enhanced in Purkinje cells by the calsyntenin-3 deletion. No changes in the dendritic architecture of Purkinje cells or in climbing-fiber synapses were detected. Sparse selective deletion of calsyntenin-3 only in Purkinje cells recapitulated the synaptic phenotype, indicating that calsyntenin-3 acts by a cell-autonomous postsynaptic mechanism in cerebellum. Thus, by inhibiting formation of excitatory parallel-fiber synapses and promoting formation of inhibitory synapses in the same neuron, calsyntenin-3 functions as a postsynaptic adhesion molecule that regulates the excitatory/inhibitory balance in Purkinje cells.
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Affiliation(s)
- Zhihui Liu
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Man Jiang
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Kif Liakath-Ali
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Alessandra Sclip
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
| | - Jaewon Ko
- Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and TechnologyDaeguRepublic of Korea
| | - Roger Shen Zhang
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
| | - Thomas C Südhof
- Department of Molecular and Cellular Physiology, Stanford UniversityStanfordUnited States
- Howard Hughes Medical Institute, Stanford UniversityStanfordUnited States
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14
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Bhandari A, Ward TW, Smith J, Van Hook MJ. Structural and functional plasticity in the dorsolateral geniculate nucleus of mice following bilateral enucleation. Neuroscience 2022; 488:44-59. [PMID: 35131394 PMCID: PMC8960354 DOI: 10.1016/j.neuroscience.2022.01.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Accepted: 01/31/2022] [Indexed: 02/08/2023]
Abstract
Within the nervous system, plasticity mechanisms attempt to stabilize network activity following disruption by injury, disease, or degeneration. Optic nerve injury and age-related diseases can induce homeostatic-like responses in adulthood. We tested this possibility in the thalamocortical (TC) neurons in the dorsolateral geniculate nucleus (dLGN) using patch-clamp electrophysiology, optogenetics, immunostaining, and single-cell dendritic analysis following loss of visual input via bilateral enucleation. We observed progressive loss of vGlut2-positive retinal terminals in the dLGN indicating degeneration post-enucleation that was coincident with changes in microglial morphology indicative of microglial activation. Consistent with the decline of vGlut2 puncta, we also observed loss of retinogeniculate (RG) synaptic function assessed using optogenetic activation of RG axons while performing whole-cell voltage clamp recordings from TC neurons in brain slices. Surprisingly, we did not detect any significant changes in the frequency of miniature post-synaptic currents (mEPSCs) or corticothalamic feedback synapses. Analysis of TC neuron dendritic structure from single-cell dye fills revealed a gradual loss of dendrites proximal to the soma, where TC neurons receive the bulk of RG inputs. Finally, analysis of action potential firing demonstrated that TC neurons have increased excitability following enucleation, firing more action potentials in response to depolarizing current injections. Our findings show that degeneration of the retinal axons/optic nerve and loss of RG synaptic inputs induces structural and functional changes in TC neurons, consistent with neuronal attempts at compensatory plasticity in the dLGN.
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15
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Batool S, Akhter B, Zaidi J, Visser F, Petrie G, Hill M, Syed NI. Neuronal Menin Overexpression Rescues Learning and Memory Phenotype in CA1-Specific α7 nAChRs KD Mice. Cells 2021; 10:3286. [PMID: 34943798 PMCID: PMC8699470 DOI: 10.3390/cells10123286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/14/2021] [Accepted: 11/17/2021] [Indexed: 01/08/2023] Open
Abstract
The perturbation of nicotinic cholinergic receptors is thought to underlie many neurodegenerative and neuropsychiatric disorders, such as Alzheimer's and schizophrenia. We previously identified that the tumor suppressor gene, MEN1, regulates both the expression and synaptic targeting of α7 nAChRs in the mouse hippocampal neurons in vitro. Here we sought to determine whether the α7 nAChRs gene expression reciprocally regulates the expression of menin, the protein encoded by the MEN1 gene, and if this interplay impacts learning and memory. We demonstrate here that α7 nAChRs knockdown (KD) both in in vitro and in vivo, initially upregulated and then subsequently downregulated menin expression. Exogenous expression of menin using an AAV transduction approach rescued α7 nAChRs KD mediated functional and behavioral deficits specifically in hippocampal (CA1) neurons. These effects involved the modulation of the α7 nAChR subunit expression and functional clustering at the synaptic sites. Our data thus demonstrates a novel and important interplay between the MEN1 gene and the α7 nAChRs in regulating hippocampal-dependent learning and memory.
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Affiliation(s)
- Shadab Batool
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.B.); (B.A.); (F.V.); (G.P.); (M.H.)
- Department of Neuroscience, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Basma Akhter
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.B.); (B.A.); (F.V.); (G.P.); (M.H.)
| | - Jawwad Zaidi
- Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada;
| | - Frank Visser
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.B.); (B.A.); (F.V.); (G.P.); (M.H.)
| | - Gavin Petrie
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.B.); (B.A.); (F.V.); (G.P.); (M.H.)
- Department of Neuroscience, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Matthew Hill
- Hotchkiss Brain Institute, University of Calgary, Calgary, AB T2N 4N1, Canada; (S.B.); (B.A.); (F.V.); (G.P.); (M.H.)
| | - Naweed I. Syed
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, AB T2N 4N1, Canada
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16
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Amorim FE, Chapot RL, Moulin TC, Lee JLC, Amaral OB. Memory destabilization during reconsolidation: a consequence of homeostatic plasticity? ACTA ACUST UNITED AC 2021; 28:371-389. [PMID: 34526382 DOI: 10.1101/lm.053418.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/14/2021] [Indexed: 11/24/2022]
Abstract
Remembering is not a static process: When retrieved, a memory can be destabilized and become prone to modifications. This phenomenon has been demonstrated in a number of brain regions, but the neuronal mechanisms that rule memory destabilization and its boundary conditions remain elusive. Using two distinct computational models that combine Hebbian plasticity and synaptic downscaling, we show that homeostatic plasticity can function as a destabilization mechanism, accounting for behavioral results of protein synthesis inhibition upon reactivation with different re-exposure times. Furthermore, by performing systematic reviews, we identify a series of overlapping molecular mechanisms between memory destabilization and synaptic downscaling, although direct experimental links between both phenomena remain scarce. In light of these results, we propose a theoretical framework where memory destabilization can emerge as an epiphenomenon of homeostatic adaptations prompted by memory retrieval.
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Affiliation(s)
- Felippe E Amorim
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Renata L Chapot
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Thiago C Moulin
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala 751 24, Sweden
| | - Jonathan L C Lee
- University of Birmingham, School of Psychology, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Olavo B Amaral
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
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17
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Hanley JG. Regulation of AMPAR expression by microRNAs. Neuropharmacology 2021; 197:108723. [PMID: 34274347 DOI: 10.1016/j.neuropharm.2021.108723] [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: 04/30/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
AMPA receptors (AMPARs) are the major excitatory neurotransmitter receptor in the brain, and their expression at synapses is a critical determinant of synaptic transmission and therefore brain function. Synaptic plasticity involves increases or decreases in synaptic strength, caused by changes in the number or subunit-specific subtype of AMPARs expressed at synapses, and resulting in modifications of functional connectivity of neuronal circuits, a process which is thought to underpin learning and the formation or loss of memories. Furthermore, numerous neurological disorders involve dysregulation of excitatory synaptic transmission or aberrant recruitment of plasticity processes. MicroRNAs (miRNAs) repress the translation of target genes by partial complementary base pairing with mRNAs, and are the core component of a mechanism widely used in a range of cell processes for regulating protein translation. MiRNA-dependent translational repression can occur locally in neuronal dendrites, close to synapses, and can also result in relatively rapid changes in protein expression. MiRNAs are therefore well-placed to regulate synaptic plasticity via the local control of AMPAR subunit synthesis, and can also result in synaptic dysfunction in the event of dysregulation in disease. Here, I will review the miRNAs that have been identified as playing a role in physiological or pathological changes in AMPAR subunit expression at synapses, focussing on miRNAs that target mRNAs encoding AMPAR subunits, and on miRNAs that target AMPAR accessory proteins involved in AMPAR trafficking and hence the regulation of AMPAR synaptic localisation.
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Affiliation(s)
- Jonathan G Hanley
- School of Biochemistry, Biomedical Sciences Building, University of Bristol, University Walk, Bristol, BS8 1TD, UK.
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18
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Pires J, Nelissen R, Mansvelder HD, Meredith RM. Spontaneous synchronous network activity in the neonatal development of mPFC in mice. Dev Neurobiol 2021; 81:207-225. [PMID: 33453138 PMCID: PMC8048581 DOI: 10.1002/dneu.22811] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 12/31/2020] [Accepted: 01/03/2021] [Indexed: 12/28/2022]
Abstract
Spontaneous Synchronous Network Activity (SSA) is a hallmark of neurodevelopment found in numerous central nervous system structures, including neocortex. SSA occurs during restricted developmental time‐windows, commonly referred to as critical periods in sensory neocortex. Although part of the neocortex, the critical period for SSA in the medial prefrontal cortex (mPFC) and the underlying mechanisms for generation and propagation are unknown. Using Ca2+ imaging and whole‐cell patch‐clamp in an acute mPFC slice mouse model, the development of spontaneous activity and SSA was investigated at cellular and network levels during the two first postnatal weeks. The data revealed that developing mPFC neuronal networks are spontaneously active and exhibit SSA in the first two postnatal weeks, with peak synchronous activity at postnatal days (P)8–9. Networks remain active but are desynchronized by the end of this 2‐week period. SSA was driven by excitatory ionotropic glutamatergic transmission with a small contribution of excitatory GABAergic transmission at early time points. The neurohormone oxytocin desynchronized SSA in the first postnatal week only without affecting concurrent spontaneous activity. By the end of the second postnatal week, inhibiting GABAA receptors restored SSA. These findings point to the emergence of GABAA receptor‐mediated inhibition as a major factor in the termination of SSA in mouse mPFC.
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Affiliation(s)
- Johny Pires
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Faculty of Science, Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, the Netherlands
| | - Rosalie Nelissen
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Faculty of Science, Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, the Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Faculty of Science, Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, the Netherlands
| | - Rhiannon M Meredith
- Department of Integrative Neurophysiology, Center for Neurogenomics & Cognitive Research, Faculty of Science, Neuroscience Campus Amsterdam, VU University Amsterdam, Amsterdam, the Netherlands
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19
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The aging mouse brain: cognition, connectivity and calcium. Cell Calcium 2021; 94:102358. [PMID: 33517250 DOI: 10.1016/j.ceca.2021.102358] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/16/2021] [Accepted: 01/18/2021] [Indexed: 02/08/2023]
Abstract
Aging is a complex process that differentially impacts multiple cognitive, sensory, neuronal and molecular processes. Technological innovations now allow for parallel investigation of neuronal circuit function, structure and molecular composition in the brain of awake behaving adult mice. Thus, mice have become a critical tool to better understand how aging impacts the brain. However, a more granular systems-based approach, which considers the impact of age on key features relating to neural processing, is required. Here, we review evidence probing the impact of age on the mouse brain. We focus on a range of processes relating to neuronal function, including cognitive abilities, sensory systems, synaptic plasticity and calcium regulation. Across many systems, we find evidence for prominent age-related dysregulation even before 12 months of age, suggesting that emerging age-related alterations can manifest by late adulthood. However, we also find reports suggesting that some processes are remarkably resilient to aging. The evidence suggests that aging does not drive a parallel, linear dysregulation of all systems, but instead impacts some processes earlier, and more severely, than others. We propose that capturing the more fine-scale emerging features of age-related vulnerability and resilience may provide better opportunities for the rejuvenation of the aged brain.
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20
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Siedlecki-Wullich D, Miñano-Molina AJ, Rodríguez-Álvarez J. microRNAs as Early Biomarkers of Alzheimer's Disease: A Synaptic Perspective. Cells 2021; 10:113. [PMID: 33435363 PMCID: PMC7827653 DOI: 10.3390/cells10010113] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 02/07/2023] Open
Abstract
Pathogenic processes underlying Alzheimer's disease (AD) affect synaptic function from initial asymptomatic stages, long time before the onset of cognitive decline and neurodegeneration. Therefore, reliable biomarkers enabling early AD diagnosis and prognosis are needed to maximize the time window for therapeutic interventions. MicroRNAs (miRNAs) have recently emerged as promising cost-effective and non-invasive biomarkers for AD, since they can be readily detected in different biofluids, including cerebrospinal fluid (CSF) and blood. Moreover, a growing body of evidence indicates that miRNAs regulate synaptic homeostasis and plasticity processes, suggesting that they may be involved in early synaptic dysfunction during AD. Here, we review the current literature supporting a role of miRNAs during early synaptic deficits in AD, including recent studies evaluating their potential as AD biomarkers. Besides targeting genes related to Aβ and tau metabolism, several miRNAs also regulate synaptic-related proteins and transcription factors implicated in early synaptic deficits during AD. Furthermore, individual miRNAs and molecular signatures have been found to distinguish between prodromal AD and healthy controls. Overall, these studies highlight the relevance of considering synaptic-related miRNAs as potential biomarkers of early AD stages. However, further validation studies in large cohorts, including longitudinal studies, as well as implementation of standardized protocols, are needed to establish miRNA-based biomarkers as reliable diagnostic and prognostic tools.
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Affiliation(s)
- Dolores Siedlecki-Wullich
- Department Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain; (A.J.M.-M.); (J.R.-Á.)
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 528031 Madrid, Spain
| | - Alfredo J. Miñano-Molina
- Department Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain; (A.J.M.-M.); (J.R.-Á.)
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 528031 Madrid, Spain
| | - José Rodríguez-Álvarez
- Department Bioquímica i Biologia Molecular, Institut de Neurociències, Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Spain; (A.J.M.-M.); (J.R.-Á.)
- Centro de Investigación Biomédica en Red Sobre Enfermedades Neurodegenerativas (CIBERNED), 528031 Madrid, Spain
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
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21
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The auxiliary glutamate receptor subunit dSol-1 promotes presynaptic neurotransmitter release and homeostatic potentiation. Proc Natl Acad Sci U S A 2020; 117:25830-25839. [PMID: 32973097 DOI: 10.1073/pnas.1915464117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Presynaptic glutamate receptors (GluRs) modulate neurotransmitter release and are physiological targets for regulation during various forms of plasticity. Although much is known about the auxiliary subunits associated with postsynaptic GluRs, far less is understood about presynaptic auxiliary GluR subunits and their functions. At the Drosophila neuromuscular junction, a presynaptic GluR, DKaiR1D, localizes near active zones and operates as an autoreceptor to tune baseline transmission and enhance presynaptic neurotransmitter release in response to diminished postsynaptic GluR functionality, a process referred to as presynaptic homeostatic potentiation (PHP). Here, we identify an auxiliary subunit that collaborates with DKaiR1D to promote these synaptic functions. This subunit, dSol-1, is the homolog of the Caenorhabditis elegans CUB (Complement C1r/C1s, Uegf, Bmp1) domain protein Sol-1. We find that dSol-1 functions in neurons to facilitate baseline neurotransmission and to enable PHP expression, properties shared with DKaiR1D Intriguingly, presynaptic overexpression of dSol-1 is sufficient to enhance neurotransmitter release through a DKaiR1D-dependent mechanism. Furthermore, dSol-1 is necessary to rapidly increase the abundance of DKaiR1D receptors near active zones during homeostatic signaling. Together with recent work showing the CUB domain protein Neto2 is necessary for the homeostatic modulation of postsynaptic GluRs in mammals, our data demonstrate that dSol-1 is required for the homeostatic regulation of presynaptic GluRs. Thus, we propose that CUB domain proteins are fundamental homeostatic modulators of GluRs on both sides of the synapse.
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22
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The vulnerability of the immature brain. HANDBOOK OF CLINICAL NEUROLOGY 2020. [PMID: 32958197 DOI: 10.1016/b978-0-444-64150-2.00010-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2023]
Abstract
The concept of vulnerability of the immature brain is multifactorial by definition. Newer scientific work in this area has shifted and enlarged the concept from theoretical frameworks to the multiple levels (molecular, cellular, anatomic, network, behavioral) of the organization of the growing brain. The concept of vulnerability was first introduced by Donald O. Hebb in the 1950s and referred to the inability of the immature brain to completely recover normal development after a brain insult. The concept of vulnerability was further extended to the limitations of the brain in the development of specific skills in neuronal substrates originally used for other functions. We present an overview of some neurodevelopmental processes that characterize the immature brain and that can predict vulnerability in the case of disturbances: Hebb's principle, synaptic homeostasis, selective vulnerability of immature cells in mammals, and inherited constraint networks. A better understanding of the vulnerability mechanisms may help in early detection and prevention and further proposed individualized therapeutic approaches to enhance children's developmental outcomes.
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23
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Koller EJ, Chakrabarty P. Tau-Mediated Dysregulation of Neuroplasticity and Glial Plasticity. Front Mol Neurosci 2020; 13:151. [PMID: 32973446 PMCID: PMC7472665 DOI: 10.3389/fnmol.2020.00151] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 07/20/2020] [Indexed: 01/14/2023] Open
Abstract
The inability of individual neurons to compensate for aging-related damage leads to a gradual loss of functional plasticity in the brain accompanied by progressive impairment in learning and memory. Whereas this loss in neuroplasticity is gradual during normal aging, in neurodegenerative diseases such as Alzheimer’s disease (AD), this loss is accelerated dramatically, leading to the incapacitation of patients within a decade of onset of cognitive symptoms. The mechanisms that underlie this accelerated loss of neuroplasticity in AD are still not completely understood. While the progressively increasing proteinopathy burden, such as amyloid β (Aβ) plaques and tau tangles, definitely contribute directly to a neuron’s functional demise, the role of non-neuronal cells in controlling neuroplasticity is slowly being recognized as another major factor. These non-neuronal cells include astrocytes, microglia, and oligodendrocytes, which through regulating brain homeostasis, structural stability, and trophic support, play a key role in maintaining normal functioning and resilience of the neuronal network. It is believed that chronic signaling from these cells affects the homeostatic network of neuronal and non-neuronal cells to an extent to destabilize this harmonious milieu in neurodegenerative diseases like AD. Here, we will examine the experimental evidence regarding the direct and indirect pathways through which astrocytes and microglia can alter brain plasticity in AD, specifically as they relate to the development and progression of tauopathy. In this review article, we describe the concepts of neuroplasticity and glial plasticity in healthy aging, delineate possible mechanisms underlying tau-induced plasticity dysfunction, and discuss current clinical trials as well as future disease-modifying approaches.
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Affiliation(s)
- Emily J Koller
- Department of Neuroscience, University of Florida, Gainesville, FL, United States.,Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States
| | - Paramita Chakrabarty
- Department of Neuroscience, University of Florida, Gainesville, FL, United States.,Center for Translational Research in Neurodegenerative Disease, University of Florida, Gainesville, FL, United States.,McKnight Brain Institute, University of Florida, Gainesville, FL, United States
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24
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Ocker GK, Buice MA. Flexible neural connectivity under constraints on total connection strength. PLoS Comput Biol 2020; 16:e1008080. [PMID: 32745134 PMCID: PMC7425997 DOI: 10.1371/journal.pcbi.1008080] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Revised: 08/13/2020] [Accepted: 06/19/2020] [Indexed: 12/23/2022] Open
Abstract
Neural computation is determined by neurons’ dynamics and circuit connectivity. Uncertain and dynamic environments may require neural hardware to adapt to different computational tasks, each requiring different connectivity configurations. At the same time, connectivity is subject to a variety of constraints, placing limits on the possible computations a given neural circuit can perform. Here we examine the hypothesis that the organization of neural circuitry favors computational flexibility: that it makes many computational solutions available, given physiological constraints. From this hypothesis, we develop models of connectivity degree distributions based on constraints on a neuron’s total synaptic weight. To test these models, we examine reconstructions of the mushroom bodies from the first instar larva and adult Drosophila melanogaster. We perform a Bayesian model comparison for two constraint models and a random wiring null model. Overall, we find that flexibility under a homeostatically fixed total synaptic weight describes Kenyon cell connectivity better than other models, suggesting a principle shaping the apparently random structure of Kenyon cell wiring. Furthermore, we find evidence that larval Kenyon cells are more flexible earlier in development, suggesting a mechanism whereby neural circuits begin as flexible systems that develop into specialized computational circuits. High-throughput electron microscopic anatomical experiments have begun to yield detailed maps of neural circuit connectivity. Uncovering the principles that govern these circuit structures is a major challenge for systems neuroscience. Healthy neural circuits must be able to perform computational tasks while satisfying physiological constraints. Those constraints can restrict a neuron’s possible connectivity, and thus potentially restrict its computation. Here we examine simple models of constraints on total synaptic weights, and calculate the number of circuit configurations they allow: a simple measure of their computational flexibility. We propose probabilistic models of connectivity that weight the number of synaptic partners according to computational flexibility under a constraint and test them using recent wiring diagrams from a learning center, the mushroom body, in the fly brain. We compare constraints that fix or bound a neuron’s total connection strength to a simple random wiring null model. Of these models, the fixed total connection strength matched the overall connectivity best in mushroom bodies from both larval and adult flies. We also provide evidence suggesting that neural circuits are more flexible in early stages of development and lose this flexibility as they grow towards specialized function.
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Affiliation(s)
- Gabriel Koch Ocker
- Allen Institute for Brain Science, Seattle, Washington, United States of America
- * E-mail:
| | - Michael A. Buice
- Allen Institute for Brain Science, Seattle, Washington, United States of America
- Department of Applied Mathematics, University of Washington, Seattle, Washington, United States of America
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Goel P, Nishimura S, Chetlapalli K, Li X, Chen C, Dickman D. Distinct Target-Specific Mechanisms Homeostatically Stabilize Transmission at Pre- and Post-synaptic Compartments. Front Cell Neurosci 2020; 14:196. [PMID: 32676010 PMCID: PMC7333441 DOI: 10.3389/fncel.2020.00196] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 06/05/2020] [Indexed: 12/28/2022] Open
Abstract
Neurons must establish and stabilize connections made with diverse targets, each with distinct demands and functional characteristics. At Drosophila neuromuscular junctions (NMJs), synaptic strength remains stable in a manipulation that simultaneously induces hypo-innervation on one target and hyper-innervation on the other. However, the expression mechanisms that achieve this exquisite target-specific homeostatic control remain enigmatic. Here, we identify the distinct target-specific homeostatic expression mechanisms. On the hypo-innervated target, an increase in postsynaptic glutamate receptor (GluR) abundance is sufficient to compensate for reduced innervation, without any apparent presynaptic adaptations. In contrast, a target-specific reduction in presynaptic neurotransmitter release probability is reflected by a decrease in active zone components restricted to terminals of hyper-innervated targets. Finally, loss of postsynaptic GluRs on one target induces a compartmentalized, homeostatic enhancement of presynaptic neurotransmitter release called presynaptic homeostatic potentiation (PHP) that can be precisely balanced with the adaptations required for both hypo- and hyper-innervation to maintain stable synaptic strength. Thus, distinct anterograde and retrograde signaling systems operate at pre- and post-synaptic compartments to enable target-specific, homeostatic control of neurotransmission.
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26
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Patel PA, Liang C, Arora A, Vijayan S, Ahuja S, Wagley PK, Settlage R, LaConte LEW, Goodkin HP, Lazar I, Srivastava S, Mukherjee K. Haploinsufficiency of X-linked intellectual disability gene CASK induces post-transcriptional changes in synaptic and cellular metabolic pathways. Exp Neurol 2020; 329:113319. [PMID: 32305418 DOI: 10.1016/j.expneurol.2020.113319] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Revised: 04/04/2020] [Accepted: 04/15/2020] [Indexed: 12/17/2022]
Abstract
Heterozygous mutations in the X-linked gene CASK are associated with intellectual disability, microcephaly, pontocerebellar hypoplasia, optic nerve hypoplasia and partially penetrant seizures in girls. The Cask+/- heterozygous knockout female mouse phenocopies the human disorder and exhibits postnatal microencephaly, cerebellar hypoplasia and optic nerve hypoplasia. It is not known if Cask+/- mice also display seizures, nor is known the molecular mechanism by which CASK haploinsufficiency produces the numerous documented phenotypes. 24-h video electroencephalography demonstrates that despite sporadic seizure activity, the overall electrographic patterns remain unaltered in Cask+/- mice. Additionally, seizure threshold to the commonly used kindling agent, pentylenetetrazol, remains unaltered in Cask+/- mice, indicating that even in mice the seizure phenotype is only partially penetrant and may have an indirect mechanism. RNA sequencing experiments on Cask+/- mouse brain uncovers a very limited number of changes, with most differences arising in the transcripts of extracellular matrix proteins and the transcripts of a group of nuclear proteins. In contrast to limited changes at the transcript level, quantitative whole-brain proteomics using iTRAQ quantitative mass-spectrometry reveals major changes in synaptic, metabolic/mitochondrial, cytoskeletal, and protein metabolic pathways. Unbiased protein-protein interaction mapping using affinity chromatography demonstrates that CASK may form complexes with proteins belonging to the same functional groups in which altered protein levels are observed. We discuss the mechanism of the observed changes in the context of known molecular function/s of CASK. Overall, our data indicate that the phenotypic spectrum of female Cask+/- mice includes sporadic seizures and thus closely parallels that of CASK haploinsufficient girls; the Cask+/- mouse is thus a face-validated model for CASK-related pathologies. We therefore surmise that CASK haploinsufficiency is likely to affect brain structure and function due to dysregulation of several cellular pathways including synaptic signaling and cellular metabolism.
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Affiliation(s)
- P A Patel
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States; Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA, United States
| | - C Liang
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - A Arora
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - S Vijayan
- School of Neuroscience, Virginia Tech, Blacksburg, VA, United States
| | - S Ahuja
- Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - P K Wagley
- Neurology, University of Virginia, Charlottesville, VA, USA
| | - R Settlage
- Advanced Research Computing, Virginia Tech, Blacksburg, VA, United States
| | - L E W LaConte
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - H P Goodkin
- Neurology, University of Virginia, Charlottesville, VA, USA
| | - I Lazar
- Biological Sciences, Virginia Tech, Blacksburg, VA, United States
| | - S Srivastava
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States
| | - K Mukherjee
- Center for Neurobiology Research, Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States; Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, United States; Department of Psychiatry and Behavioral Medicine, Virginia Tech Carilion School of Medicine, Roanoke, VA, United States.
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Sial OK, Parise EM, Parise LF, Gnecco T, Bolaños-Guzmán CA. Ketamine: The final frontier or another depressing end? Behav Brain Res 2020; 383:112508. [PMID: 32017978 PMCID: PMC7127859 DOI: 10.1016/j.bbr.2020.112508] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 01/15/2020] [Accepted: 01/23/2020] [Indexed: 12/12/2022]
Abstract
Two decades ago, the observation of a rapid and sustained antidepressant response after ketamine administration provided an exciting new avenue in the search for more effective therapeutics for the treatment of clinical depression. Research elucidating the mechanism(s) underlying ketamine's antidepressant properties has led to the development of several hypotheses, including that of disinhibition of excitatory glutamate neurons via blockade of N-methyl-d-aspartate (NMDA) receptors. Although the prominent understanding has been that ketamine's mode of action is mediated solely via the NMDA receptor, this view has been challenged by reports implicating other glutamate receptors such as AMPA, and other neurotransmitter systems such as serotonin and opioids in the antidepressant response. The recent approval of esketamine (Spravato™) for the treatment of depression has sparked a resurgence of interest for a deeper understanding of the mechanism(s) underlying ketamine's actions and safe therapeutic use. This review aims to present our current knowledge on both NMDA and non-NMDA mechanisms implicated in ketamine's response, and addresses the controversy surrounding the antidepressant role and potency of its stereoisomers and metabolites. There is much that remains to be known about our understanding of ketamine's antidepressant properties; and although the arrival of esketamine has been received with great enthusiasm, it is now more important than ever that its mechanisms of action be fully delineated, and both the short- and long-term neurobiological/functional consequences of its treatment be thoroughly characterized.
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MESH Headings
- Antidepressive Agents/pharmacology
- Antidepressive Agents/therapeutic use
- Depressive Disorder, Major/drug therapy
- Depressive Disorder, Treatment-Resistant/drug therapy
- Dopamine Plasma Membrane Transport Proteins/drug effects
- Excitatory Amino Acid Antagonists/pharmacology
- Excitatory Amino Acid Antagonists/therapeutic use
- Humans
- Ketamine/pharmacology
- Ketamine/therapeutic use
- Norepinephrine Plasma Membrane Transport Proteins/drug effects
- Receptor, Muscarinic M1/drug effects
- Receptors, AMPA/drug effects
- Receptors, Dopamine D2/drug effects
- Receptors, N-Methyl-D-Aspartate/drug effects
- Receptors, Opioid, delta/drug effects
- Receptors, Opioid, kappa/drug effects
- Receptors, Opioid, mu/drug effects
- Receptors, Serotonin, 5-HT3/drug effects
- Receptors, sigma/drug effects
- Serotonin Plasma Membrane Transport Proteins/drug effects
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Affiliation(s)
- Omar K Sial
- Texas A&M University: Department of Psychological and Brain Sciences, 4325 TAMU, College Station, TX, 77843, USA
| | - Eric M Parise
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA
| | - Lyonna F Parise
- Fishberg Department of Neuroscience, Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY, 10029, USA
| | - Tamara Gnecco
- Texas A&M University: Department of Psychological and Brain Sciences, 4325 TAMU, College Station, TX, 77843, USA
| | - Carlos A Bolaños-Guzmán
- Texas A&M University: Department of Psychological and Brain Sciences, 4325 TAMU, College Station, TX, 77843, USA.
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Activity Dependent and Independent Determinants of Synaptic Size Diversity. J Neurosci 2020; 40:2828-2848. [PMID: 32127494 DOI: 10.1523/jneurosci.2181-19.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Revised: 02/04/2020] [Accepted: 02/13/2020] [Indexed: 11/21/2022] Open
Abstract
The extraordinary diversity of excitatory synapse sizes is commonly attributed to activity-dependent processes that drive synaptic growth and diminution. Recent studies also point to activity-independent size fluctuations, possibly driven by innate synaptic molecule dynamics, as important generators of size diversity. To examine the contributions of activity-dependent and independent processes to excitatory synapse size diversity, we studied glutamatergic synapse size dynamics and diversification in cultured rat cortical neurons (both sexes), silenced from plating. We found that in networks with no history of activity whatsoever, synaptic size diversity was no less extensive than that observed in spontaneously active networks. Synapses in silenced networks were larger, size distributions were broader, yet these were rightward-skewed and similar in shape when scaled by mean synaptic size. Silencing reduced the magnitude of size fluctuations and weakened constraints on size distributions, yet these were sufficient to explain synaptic size diversity in silenced networks. Model-based exploration followed by experimental testing indicated that silencing-associated changes in innate molecular dynamics and fluctuation characteristics might negatively impact synaptic persistence, resulting in reduced synaptic numbers. This, in turn, would increase synaptic molecule availability, promote synaptic enlargement, and ultimately alter fluctuation characteristics. These findings suggest that activity-independent size fluctuations are sufficient to fully diversify glutamatergic synaptic sizes, with activity-dependent processes primarily setting the scale rather than the shape of size distributions. Moreover, they point to reciprocal relationships between synaptic size fluctuations, size distributions, and synaptic numbers mediated by the innate dynamics of synaptic molecules as they move in, out, and between synapses.SIGNIFICANCE STATEMENT Sizes of glutamatergic synapses vary tremendously, even when formed on the same neuron. This diversity is commonly thought to reflect the outcome of activity-dependent forms of synaptic plasticity, yet activity-independent processes might also play some part. Here we show that in neurons with no history of activity whatsoever, synaptic sizes are no less diverse. We show that this diversity is the product of activity-independent size fluctuations, which are sufficient to generate a full repertoire of synaptic sizes at correct proportions. By combining modeling and experimentation we expose reciprocal relationships between size fluctuations, synaptic sizes and synaptic counts, and show how these phenomena might be connected through the dynamics of synaptic molecules as they move in, out, and between synapses.
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29
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Lewis V, Laberge F, Heyland A. Temporal Profile of Brain Gene Expression After Prey Catching Conditioning in an Anuran Amphibian. Front Neurosci 2020; 13:1407. [PMID: 31992968 PMCID: PMC6971186 DOI: 10.3389/fnins.2019.01407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 12/12/2019] [Indexed: 12/19/2022] Open
Abstract
A key goal in modern neurobiology is to understand the mechanisms underlying learning and memory. To that end, it is essential to identify the patterns of gene expression and the temporal sequence of molecular events associated with learning and memory processes. It is also important to ascertain if and how these molecular events vary between organisms. In vertebrates, learning and memory processes are characterized by distinct phases of molecular activity involving gene transcription, structural change, and long-term maintenance of such structural change in the nervous system. Utilizing next generation sequencing techniques, we profiled the temporal expression patterns of genes in the brain of the fire-bellied toad Bombina orientalis after prey catching conditioning. The fire-bellied toad is a basal tetrapod whose neural architecture and molecular pathways may help us understand the ancestral state of learning and memory mechanisms in tetrapods. Differential gene expression following conditioning revealed activity in molecular pathways related to immediate early genes (IEG), cytoskeletal modification, axon guidance activity, and apoptotic processes. Conditioning induced early IEG activity coinciding with transcriptional activity and neuron structural modification, followed by axon guidance and cell adhesion activity, and late neuronal pruning. While some of these gene expression patterns are similar to those found in mammals submitted to conditioning, some interesting divergent expression profiles were seen, and differential expression of some well-known learning-related mammalian genes is missing altogether. These results highlight the importance of using a comparative approach in the study of the mechanisms of leaning and memory and provide molecular resources for a novel vertebrate model in the relatively poorly studied Amphibia.
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Affiliation(s)
- Vern Lewis
- Integrative Biology, University of Guelph, Guelph, ON, Canada
| | | | - Andreas Heyland
- Integrative Biology, University of Guelph, Guelph, ON, Canada
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30
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Ismail FY, Ljubisavljevic MR, Johnston MV. A conceptual framework for plasticity in the developing brain. HANDBOOK OF CLINICAL NEUROLOGY 2020; 173:57-66. [PMID: 32958193 DOI: 10.1016/b978-0-444-64150-2.00007-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this chapter, we highlight the various definitions of early brain plasticity commonly used in the scientific literature. We then present a conceptual framework of early brain plasticity that focuses on plasticity at the level of the synapse (synaptic plasticity) and the level of the network (connectivity). The proposed framework is organized around three main domains through which current theories and principles of early brain plasticity can be integrated: (1) the mechanisms of plasticity and constraints at the synaptic level and network connectivity, (2) the importance of temporal considerations related to the development of the immature brain, and (3) the functions early brain plasticity serve. We then apply this framework to discuss some clinical disorders caused by and/or associated with impaired plasticity mechanisms. We propose that a careful examination of the relationship between mechanisms, constraints, and functions of early brain plasticity in health and disease may provide an integrative understanding of the current theories and principles generated by experimental and observational studies.
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Affiliation(s)
- Fatima Y Ismail
- Department of Pediatrics, United Arab Emirates University, Al-Ain, United Arab Emirates; Department of Neurology (adjunct), Johns Hopkins School of Medicine, Baltimore, MD, United States.
| | | | - Michael V Johnston
- Department of Neurology and Developmental Medicine, Kennedy Krieger Institute, Baltimore, MD, United States
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31
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Hammer MF, Sprissler R, Bina RW, Lau B, Johnstone L, Walter CM, Labiner DM, Weinand ME. Altered expression of signaling pathways regulating neuronal excitability in hippocampal tissue of temporal lobe epilepsy patients with low and high seizure frequency. Epilepsy Res 2019; 155:106145. [DOI: 10.1016/j.eplepsyres.2019.05.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 05/17/2019] [Accepted: 05/23/2019] [Indexed: 12/22/2022]
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32
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Bissen D, Foss F, Acker-Palmer A. AMPA receptors and their minions: auxiliary proteins in AMPA receptor trafficking. Cell Mol Life Sci 2019; 76:2133-2169. [PMID: 30937469 PMCID: PMC6502786 DOI: 10.1007/s00018-019-03068-7] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 02/12/2019] [Accepted: 03/07/2019] [Indexed: 12/12/2022]
Abstract
To correctly transfer information, neuronal networks need to continuously adjust their synaptic strength to extrinsic stimuli. This ability, termed synaptic plasticity, is at the heart of their function and is, thus, tightly regulated. In glutamatergic neurons, synaptic strength is controlled by the number and function of AMPA receptors at the postsynapse, which mediate most of the fast excitatory transmission in the central nervous system. Their trafficking to, at, and from the synapse, is, therefore, a key mechanism underlying synaptic plasticity. Intensive research over the last 20 years has revealed the increasing importance of interacting proteins, which accompany AMPA receptors throughout their lifetime and help to refine the temporal and spatial modulation of their trafficking and function. In this review, we discuss the current knowledge about the roles of key partners in regulating AMPA receptor trafficking and focus especially on the movement between the intracellular, extrasynaptic, and synaptic pools. We examine their involvement not only in basal synaptic function, but also in Hebbian and homeostatic plasticity. Included in our review are well-established AMPA receptor interactants such as GRIP1 and PICK1, the classical auxiliary subunits TARP and CNIH, and the newest additions to AMPA receptor native complexes.
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Affiliation(s)
- Diane Bissen
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
- Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438, Frankfurt am Main, Germany
| | - Franziska Foss
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany
| | - Amparo Acker-Palmer
- Institute of Cell Biology and Neuroscience and Buchmann Institute for Molecular Life Sciences (BMLS), University of Frankfurt, Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany.
- Max Planck Institute for Brain Research, Max von Laue Str. 4, 60438, Frankfurt am Main, Germany.
- Cardio-Pulmonary Institute (CPI), Max-von-Laue-Str. 15, 60438, Frankfurt am Main, Germany.
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33
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Garrido-García A, de Andrés R, Jiménez-Pompa A, Soriano P, Sanz-Fuentes D, Martínez-Blanco E, Díez-Guerra FJ. Neurogranin Expression Is Regulated by Synaptic Activity and Promotes Synaptogenesis in Cultured Hippocampal Neurons. Mol Neurobiol 2019; 56:7321-7337. [PMID: 31020616 DOI: 10.1007/s12035-019-1593-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/02/2019] [Indexed: 01/09/2023]
Abstract
Neurogranin (Ng) is a calmodulin (CaM)-binding protein that is phosphorylated by protein kinase C (PKC) and is highly enriched in the dendrites and spines of telencephalic neurons. It is proposed to be involved in regulating CaM availability in the post-synaptic environment to modulate the efficiency of excitatory synaptic transmission. There is a close relationship between Ng and cognitive performance; its expression peaks in the forebrain coinciding with maximum synaptogenic activity, and it is reduced in several conditions of impaired cognition. We studied the expression of Ng in cultured hippocampal neurons and found that both protein and mRNA levels were about 10% of that found in the adult hippocampus. Long-term blockade of NMDA receptors substantially decreased Ng expression. On the other hand, treatments that enhanced synaptic activity such as long-term bicuculline treatment or co-culture with glial cells or cholesterol increased Ng expression. Chemical long-term potentiation (cLTP) induced an initial drop of Ng, with a minimum after 15 min followed by a slow recovery during the next 2-4 h. This effect was most evident in the synaptosome-enriched fraction, thus suggesting local synthesis in dendrites. Lentiviral expression of Ng led to increased density of both excitatory and inhibitory synapses in the second and third weeks of culture. These results indicate that Ng expression is regulated by synaptic activity and that Ng promotes the synaptogenesis process. Given its relationship with cognitive function, we propose targeting of Ng expression as a promising strategy to prevent or alleviate the cognitive deficits associated with aging and neuropathological conditions.
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Affiliation(s)
- Alberto Garrido-García
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Instituto Cajal (CSIC), Av. Doctor Arce, 37, 28002, Madrid, Spain
| | - Raquel de Andrés
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Amanda Jiménez-Pompa
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
- Departamento de Farmacología y Terapéutica, Facultad de Medicina, Universidad Autónoma de Madrid, Madrid, Spain
| | - Patricia Soriano
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Diego Sanz-Fuentes
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - Elena Martínez-Blanco
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - F Javier Díez-Guerra
- Departamento de Biología Molecular and Centro de Biología Molecular "Severo Ochoa" (UAM-CSIC), Universidad Autónoma de Madrid, 28049, Madrid, Spain.
- Laboratory of Neuronal Plasticity, Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Nicolás Cabrera, 1, 28049, Madrid, Spain.
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A Screen for Synaptic Growth Mutants Reveals Mechanisms That Stabilize Synaptic Strength. J Neurosci 2019; 39:4051-4065. [PMID: 30902873 DOI: 10.1523/jneurosci.2601-18.2019] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Revised: 03/12/2019] [Accepted: 03/14/2019] [Indexed: 01/28/2023] Open
Abstract
Synapses grow, prune, and remodel throughout development, experience, and disease. This structural plasticity can destabilize information transfer in the nervous system. However, neural activity remains stable throughout life, implying that adaptive countermeasures exist that maintain neurotransmission within proper physiological ranges. Aberrant synaptic structure and function have been associated with a variety of neural diseases, including Fragile X syndrome, autism, and intellectual disability. We have screened 300 mutants in Drosophila larvae of both sexes for defects in synaptic growth at the neuromuscular junction, identifying 12 mutants with severe reductions or enhancements in synaptic growth. Remarkably, electrophysiological recordings revealed that synaptic strength was unchanged in all but one of these mutants compared with WT. We used a combination of genetic, anatomical, and electrophysiological analyses to illuminate three mechanisms that stabilize synaptic strength despite major disparities in synaptic growth. These include compensatory changes in (1) postsynaptic neurotransmitter receptor abundance, (2) presynaptic morphology, and (3) active zone structure. Together, this characterization identifies new mutants with defects in synaptic growth and the adaptive strategies used by synapses to homeostatically stabilize neurotransmission in response.SIGNIFICANCE STATEMENT This study reveals compensatory mechanisms used by synapses to ensure stable functionality during severe alterations in synaptic growth using the neuromuscular junction of Drosophila melanogaster as a model system. Through a forward genetic screen, we identify mutants that exhibit dramatic undergrown or overgrown synapses yet express stable levels of synaptic strength, with three specific compensatory mechanisms discovered. Thus, this study reveals novel insights into the adaptive strategies that constrain neurotransmission within narrow physiological ranges while allowing considerable flexibility in overall synapse number. More broadly, these findings provide insights into how stable synaptic function may be maintained in the nervous system during periods of intensive synaptic growth, pruning, and remodeling.
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Abstract
The formation of correct synaptic structures and neuronal connections is paramount for normal brain development and a functioning adult brain. The integrin family of cell adhesion receptors and their ligands play essential roles in the control of several processes regulating neuronal connectivity - including neurite outgrowth, the formation and maintenance of synapses, and synaptic plasticity - that are affected in neurodevelopmental disorders, such as autism spectrum disorders (ASDs) and schizophrenia. Many ASD- and schizophrenia-associated genes are linked to alterations in the genetic code of integrins and associated signalling pathways. In non-neuronal cells, crosstalk between integrin-mediated adhesions and the actin cytoskeleton, and the regulation of integrin activity (affinity for extracellular ligands) are widely studied in healthy and pathological settings. In contrast, the roles of integrin-linked pathways in the central nervous system remains less well defined. In this Review, we will provide an overview of the known pathways that are regulated by integrin-ECM interaction in developing neurons and in adult brain. We will also describe recent advances in the identification of mechanisms that regulate integrin activity in neurons, and highlight the interesting emerging links between integrins and neurodevelopment.
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Affiliation(s)
- Johanna Lilja
- Turku Centre for Biotechnology, University of Turku, FIN-20520 Turku, Finland
| | - Johanna Ivaska
- Turku Centre for Biotechnology, University of Turku, FIN-20520 Turku, Finland .,Department of Biochemistry, University of Turku, FIN-20500 Turku, Finland
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