1
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Rahmi U, Goenawan H, Sylviana N, Setiawan I, Putri ST, Andriyani S, Fitriana LA. Exercise induction at expression immediate early gene (c-Fos, ARC, EGR-1) in the hippocampus: a systematic review. Dement Neuropsychol 2024; 18:e20230015. [PMID: 38628561 PMCID: PMC11019719 DOI: 10.1590/1980-5764-dn-2023-0015] [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: 03/16/2023] [Revised: 11/06/2023] [Accepted: 11/17/2023] [Indexed: 04/19/2024] Open
Abstract
The immediate early gene exhibits activation markers in the nervous system consisting of ARC, EGR-1, and c-Fos and is related to synaptic plasticity, especially in the hippocampus. Immediate early gene expression is affected by physical exercise, which induces direct ARC, EGR-1, and c-Fos expression. Objective To assess the impact of exercise, we conducted a literature study to determine the expression levels of immediate early genes (ARC, c-Fos, and EGR-1). Methods The databases accessed for online literature included PubMed-Medline, Scopus, and ScienceDirect. The original English articles were selected using the following keywords in the title: (Exercise OR physical activity) AND (c-Fos) AND (Hippocampus), (Exercise OR physical activity) AND (ARC) AND (Hippocampus), (Exercise OR physical activity) AND (EGR-1 OR zif268) AND (Hippocampus). Results Physical exercise can affect the expression of EGR-1, c-Fos, and ARC in the hippocampus, an important part of the brain involved in learning and memory. High-intensity physical exercise can increase c-Fos expression, indicating neural activation. Furthermore, the expression of the ARC gene also increases due to physical exercise. ARC is a gene that plays a role in synaptic plasticity and regulation of learning and memory, changes in synaptic structure and increased synaptic connections, while EGR-1 also plays a role in synaptic plasticity, a genetic change that affects learning and memory. Overall, exercise or regular physical exercise can increase the expression of ARC, c-Fos, and EGR-1 in the hippocampus. This reflects the changes in neuroplasticity and synaptic plasticity that occur in response to physical activity. These changes can improve cognitive function, learning, and memory. Conclusion c-Fos, EGR-1, and ARC expression increases in hippocampal neurons after exercise, enhancing synaptic plasticity and neurogenesis associated with learning and memory.
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Affiliation(s)
- Upik Rahmi
- Universitas Pendidikan Indonesia, Department of Nursing, Bandung, West Java, Indonesia
- Universitas Padjadjaran, Department of Medicine, Bandung, West Java, Indonesia
| | - Hanna Goenawan
- Universitas Padjadjaran, Department of Medicine, Bandung, West Java, Indonesia
| | - Nova Sylviana
- Universitas Padjadjaran, Department of Medicine, Bandung, West Java, Indonesia
| | - Iwan Setiawan
- Universitas Padjadjaran, Department of Medicine, Bandung, West Java, Indonesia
| | - Suci Tuty Putri
- Universitas Pendidikan Indonesia, Department of Nursing, Bandung, West Java, Indonesia
| | - Septian Andriyani
- Universitas Pendidikan Indonesia, Department of Nursing, Bandung, West Java, Indonesia
| | - Lisna Anisa Fitriana
- Universitas Pendidikan Indonesia, Department of Nursing, Bandung, West Java, Indonesia
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2
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Atta-Ur-Rahman. Protein Folding and Molecular Basis of Memory: Molecular Vibrations and Quantum Entanglement as Basis of Consciousness. Curr Med Chem 2024; 31:258-265. [PMID: 37424348 DOI: 10.2174/0929867331666230707123345] [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: 04/30/2023] [Revised: 06/28/2023] [Accepted: 06/28/2023] [Indexed: 07/11/2023]
Affiliation(s)
- Atta-Ur-Rahman
- Kings College, University of Cambridge, Cambridge CB2 1st, United Kingdom
- H.E.J. Research Institute of Chemistry, International Center for Chemical and Biological Sciences, University of Karachi, Karachi 75270, Pakistan
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3
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Yang L, Liu W, Shi L, Wu J, Zhang W, Chuang YA, Redding-Ochoa J, Kirkwood A, Savonenko AV, Worley PF. NMDA Receptor-Arc Signaling Is Required for Memory Updating and Is Disrupted in Alzheimer's Disease. Biol Psychiatry 2023; 94:706-720. [PMID: 36796600 PMCID: PMC10423741 DOI: 10.1016/j.biopsych.2023.02.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 02/16/2023]
Abstract
BACKGROUND Memory deficits are central to many neuropsychiatric diseases. During acquisition of new information, memories can become vulnerable to interference, yet mechanisms that underlie interference are unknown. METHODS We describe a novel transduction pathway that links the NMDA receptor (NMDAR) to AKT signaling via the immediate early gene Arc and evaluate its role in memory. The signaling pathway is validated using biochemical tools and transgenic mice, and function is evaluated in assays of synaptic plasticity and behavior. The translational relevance is evaluated in human postmortem brain. RESULTS Arc is dynamically phosphorylated by CaMKII (calcium/calmodulin-dependent protein kinase II) and binds the NMDAR subunits NR2A/NR2B and a previously unstudied PI3K (phosphoinositide 3-kinase) adapter p55PIK (PIK3R3) in vivo in response to novelty or tetanic stimulation in acute slices. NMDAR-Arc-p55PIK recruits p110α PI3K and mTORC2 (mechanistic target of rapamycin complex 2) to activate AKT. NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT assembly occurs within minutes of exploratory behavior and localizes to sparse synapses throughout hippocampal and cortical regions. Studies using conditional (Nestin-Cre) p55PIK deletion mice indicate that NMDAR-Arc-p55PIK-PI3K-mTORC2-AKT functions to inhibit GSK3 and mediates input-specific metaplasticity that protects potentiated synapses from subsequent depotentiation. p55PIK conditional knockout mice perform normally in multiple behaviors including working memory and long-term memory tasks but exhibit deficits indicative of increased vulnerability to interference in both short-term and long-term paradigms. The NMDAR-AKT transduction complex is reduced in postmortem brain of individuals with early Alzheimer's disease. CONCLUSIONS A novel function of Arc mediates synapse-specific NMDAR-AKT signaling and metaplasticity that contributes to memory updating and is disrupted in human cognitive disease.
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Affiliation(s)
- Liuqing Yang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wenxue Liu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Linyuan Shi
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Jing Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wenchi Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Yang-An Chuang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Javier Redding-Ochoa
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alfredo Kirkwood
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Alena V Savonenko
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| | - Paul F Worley
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
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4
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Chen T, Xu YP, Chen Y, Sun S, Yan ZZ, Wang YH. Arc regulates brain damage and neuroinflammation via Sirt1 signaling following subarachnoid hemorrhage. Brain Res Bull 2023; 203:110780. [PMID: 37820952 DOI: 10.1016/j.brainresbull.2023.110780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 10/04/2023] [Accepted: 10/09/2023] [Indexed: 10/13/2023]
Abstract
Aneurysmal subarachnoid hemorrhage (aSAH) accounts for only 5 % of all stroke cases, but carries a heavy burden of morbidity and mortality. Activity regulated cytoskeleton associated protein (Arc) is an immediate early gene (IEG)-coded postsynaptic protein that is involved in synaptic plasticity. Increasing evidence and our previous studies have shown that Arc might be involved in the pathological mechanism of various neurological diseases, such as traumatic brain injury (TBI). In this study, we investigated the level of Arc in cerebrospinal fluids (CSF) of aSAH patients and its potential role in brain damage following experimental SAH model. We found that the levels of Arc in aSAH patients' CSF positively correlated with Hunt-Hess (H&H) grades. Knockdown of endogenous Arc expression by small interfere RNA (siRNA) significantly increased brain edema and oxidative stress following SAH. The results of immunostaining in brain sections showed that knockdown of Arc enhanced activation of microglia and astrocytes. In congruent, generation of inflammatory cytokines following SAH was increased by Si-Arc transfection. The results of western blot analysis showed that knockdown of Arc inhibited the expression of Sirt1 and Nrf2, which was accompanied by decreased enzymatic activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-px). In addition, activation of sirtuin 1 (Sirt1) via agonist SRT2104 markedly decreased the brain damage and neuroinflammation induced by Arc knockdown. In conclusion, knockdown of endogenous Arc could aggravate brain damage and neuroinflammation following experimental SAH, and Arc levels in aSAH patients' CSF might be a potential indicator of brain damage and prognosis.
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Affiliation(s)
- Tao Chen
- Department of Neurosurgery, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China
| | - Ye-Ping Xu
- Department of Neurosurgery, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China
| | - Yang Chen
- Department of Neurology, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China
| | - Shu Sun
- Department of Pharmacy, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China
| | - Zhi-Zhong Yan
- Department of Neurosurgery, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China
| | - Yu-Hai Wang
- Department of Neurosurgery, Wuxi Taihu Hospital, Wuxi Clinical College of Anhui Medical University, Wuxi, Jiangsu 214044, China.
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5
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Chen Y, Wang X, Xiao B, Luo Z, Long H. Mechanisms and Functions of Activity-Regulated Cytoskeleton-Associated Protein in Synaptic Plasticity. Mol Neurobiol 2023; 60:5738-5754. [PMID: 37338805 DOI: 10.1007/s12035-023-03442-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 06/10/2023] [Indexed: 06/21/2023]
Abstract
Activity-regulated cytoskeleton-associated protein (Arc) is one of the most important regulators of cognitive functions in the brain regions. As a hub protein, Arc plays different roles in modulating synaptic plasticity. Arc supports the maintenance of long-term potentiation (LTP) by regulating actin cytoskeletal dynamics, while it guides the endocytosis of AMPAR in long-term depression (LTD). Moreover, Arc can self-assemble into capsids, leading to a new way of communicating among neurons. The transcription and translation of the immediate early gene Arc are rigorous procedures guided by numerous factors, and RNA polymerase II (Pol II) is considered to regulate the precise timing dynamics of gene expression. Since astrocytes can secrete brain-derived neurotrophic factor (BDNF) and L-lactate, their unique roles in Arc expression are emphasized. Here, we review the entire process of Arc expression and summarize the factors that can affect Arc expression and function, including noncoding RNAs, transcription factors, and posttranscriptional regulations. We also attempt to review the functional states and mechanisms of Arc in modulating synaptic plasticity. Furthermore, we discuss the recent progress in understanding the roles of Arc in the occurrence of major neurological disorders and provide new thoughts for future research on Arc.
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Affiliation(s)
- Yifan Chen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Xiangya School of Stomatology, Central South University, Changsha, 410008, Hunan, China
| | - Xiaohu Wang
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Bo Xiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, People's Republic of China, 410008
| | - Zhaohui Luo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, People's Republic of China, 410008.
| | - Hongyu Long
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China.
- Clinical Research Center for Epileptic Disease of Hunan Province, Central South University, Changsha, Hunan, People's Republic of China, 410008.
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6
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Das S, Lituma PJ, Castillo PE, Singer RH. Maintenance of a short-lived protein required for long-term memory involves cycles of transcription and local translation. Neuron 2023; 111:2051-2064.e6. [PMID: 37100055 PMCID: PMC10330212 DOI: 10.1016/j.neuron.2023.04.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Revised: 01/03/2023] [Accepted: 04/03/2023] [Indexed: 04/28/2023]
Abstract
Activity-dependent expression of immediate early genes (IEGs) is critical for long-term synaptic remodeling and memory. It remains unknown how IEGs are maintained for memory despite rapid transcript and protein turnover. To address this conundrum, we monitored Arc, an IEG essential for memory consolidation. Using a knockin mouse where endogenous Arc alleles were fluorescently tagged, we performed real-time imaging of Arc mRNA dynamics in individual neurons in cultures and brain tissue. Unexpectedly, a single burst stimulation was sufficient to induce cycles of transcriptional reactivation in the same neuron. Subsequent transcription cycles required translation, whereby new Arc proteins engaged in autoregulatory positive feedback to reinduce transcription. The ensuing Arc mRNAs preferentially localized at sites marked by previous Arc protein, assembling a "hotspot" of translation, and consolidating "hubs" of dendritic Arc. These cycles of transcription-translation coupling sustain protein expression and provide a mechanism by which a short-lived event may support long-term memory.
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Affiliation(s)
- Sulagna Das
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Program in RNA Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
| | - Pablo J Lituma
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Program in RNA Biology, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA; Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, NY 10461, USA.
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7
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Wilkerson JR, Ifrim MF, Valdez-Sinon AN, Hahn P, Bowles JE, Molinaro G, Janusz-Kaminska A, Bassell GJ, Huber KM. FMRP phosphorylation and interactions with Cdh1 regulate association with dendritic RNA granules and MEF2-triggered synapse elimination. Neurobiol Dis 2023; 182:106136. [PMID: 37120096 PMCID: PMC10370323 DOI: 10.1016/j.nbd.2023.106136] [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: 02/20/2023] [Revised: 04/12/2023] [Accepted: 04/24/2023] [Indexed: 05/01/2023] Open
Abstract
Fragile X Messenger Ribonucleoprotein (FMRP) is necessary for experience-dependent, developmental synapse elimination and the loss of this process may underlie the excess dendritic spines and hyperconnectivity of cortical neurons in Fragile X Syndrome, a common inherited form of intellectual disability and autism. Little is known of the signaling pathways that regulate synapse elimination and if or how FMRP is regulated during this process. We have characterized a model of synapse elimination in CA1 neurons of organotypic hippocampal slice cultures that is induced by expression of the active transcription factor Myocyte Enhancer Factor 2 (MEF2) and relies on postsynaptic FMRP. MEF2-induced synapse elimination is deficient in Fmr1 KO CA1 neurons, and is rescued by acute (24 h), postsynaptic and cell autonomous reexpression of FMRP in CA1 neurons. FMRP is an RNA binding protein that suppresses mRNA translation. Derepression is induced by posttranslational mechanisms downstream of metabotropic glutamate receptor signaling. Dephosphorylation of FMRP at S499 triggers ubiquitination and degradation of FMRP which then relieves translation suppression and promotes synthesis of proteins encoded by target mRNAs. Whether this mechanism functions in synapse elimination is not known. Here we demonstrate that phosphorylation and dephosphorylation of FMRP at S499 are both necessary for synapse elimination as well as interaction of FMRP with its E3 ligase for FMRP, APC/Cdh1. Using a bimolecular ubiquitin-mediated fluorescence complementation (UbFC) assay, we demonstrate that MEF2 promotes ubiquitination of FMRP in CA1 neurons that relies on activity and interaction with APC/Cdh1. Our results suggest a model where MEF2 regulates posttranslational modifications of FMRP via APC/Cdh1 to regulate translation of proteins necessary for synapse elimination.
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Affiliation(s)
- Julia R Wilkerson
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Marius F Ifrim
- Department of Cell and Developmental Biology, State University of New York, Upstate Medical University, Syracuse, NY 13210, USA; Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | | | - Patricia Hahn
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Jacob E Bowles
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | - Gemma Molinaro
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA
| | | | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Kimberly M Huber
- Department of Neuroscience, O'Donnell Brain Institute, UT Southwestern Medical Center, Dallas, TX, USA.
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8
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Eriksen MS, Bramham CR. Molecular physiology of Arc/Arg3.1: The oligomeric state hypothesis of synaptic plasticity. Acta Physiol (Oxf) 2022; 236:e13886. [PMID: 36073248 PMCID: PMC9787330 DOI: 10.1111/apha.13886] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 08/15/2022] [Accepted: 09/05/2022] [Indexed: 01/29/2023]
Abstract
The immediate early gene, Arc, is a pivotal regulator of synaptic plasticity, memory, and cognitive flexibility. But what is Arc protein? How does it work? Inside the neuron, Arc is a protein interaction hub and dynamic regulator of intra-cellular signaling in synaptic plasticity. In remarkable contrast, Arc can also self-assemble into retrovirus-like capsids that are released in extracellular vesicles and capable of intercellular transfer of RNA. Elucidation of the molecular basis of Arc hub and capsid functions, and the relationship between them, is vital for progress. Here, we discuss recent findings on Arc structure-function and regulation of oligomerization that are giving insight into the molecular physiology of Arc. The unique features of mammalian Arc are emphasized, while drawing comparisons with Drosophila Arc and retroviral Gag. The Arc N-terminal domain, found only in mammals, is proposed to play a key role in regulating Arc hub signaling, oligomerization, and formation of capsids. Bringing together several lines of evidence, we hypothesize that Arc function in synaptic plasticity-long-term potentiation (LTP) and long-term depression (LTD)-are dictated by different oligomeric forms of Arc. Specifically, monomer/dimer function in LTP, tetramer function in basic LTD, and 32-unit oligomer function in enhanced LTD. The role of mammalian Arc capsids is unclear but likely depends on the cross-section of captured neuronal activity-induced RNAs. As the functional states of Arc are revealed, it may be possible to selectively manipulate specific forms of Arc-dependent plasticity and intercellular communication involved in brain function and dysfunction.
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Affiliation(s)
| | - Clive R. Bramham
- Department of BiomedicineUniversity of BergenBergenNorway,Mohn Research Center for the BrainUniversity of BergenBergenNorway
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9
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Sterin I, Santos AC, Park S. Neuronal Activity Reporters as Drug Screening Platforms. MICROMACHINES 2022; 13:1500. [PMID: 36144123 PMCID: PMC9504476 DOI: 10.3390/mi13091500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/25/2022] [Accepted: 09/06/2022] [Indexed: 06/16/2023]
Abstract
Understanding how neuronal activity changes and detecting such changes in both normal and disease conditions is of fundamental importance to the field of neuroscience. Neuronal activity plays important roles in the formation and function of both synapses and circuits, and dysregulation of these processes has been linked to a number of debilitating diseases such as autism, schizophrenia, and epilepsy. Despite advances in our understanding of synapse biology and in how it is altered in disease, the development of therapeutics for these diseases has not advanced apace. Many neuronal activity assays have been developed over the years using a variety of platforms and approaches, but major limitations persist. Current assays, such as fluorescence indicators are not designed to monitor neuronal activity over a long time, they are typically low-throughput or lack sensitivity. These are major barriers to the development of new therapies, as drug screening needs to be both high-throughput to screen through libraries of compounds, and longitudinal to detect any effects that may emerge after continued application of the drug. This review will cover existing assays for measuring neuronal activity and highlight a live-cell assay recently developed. This assay can be performed with easily accessible lab equipment, is both scalable and longitudinal, and can be combined with most other established methods.
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Affiliation(s)
- Igal Sterin
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
| | - Ana C. Santos
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
- Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA
| | - Sungjin Park
- Department of Neurobiology, University of Utah School of Medicine, Salt Lake City, UT 84112, USA
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10
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Hedde PN, Barylko B, Binns DD, Jameson DM, Albanesi JP. Differential Mobility and Self-Association of Arc/Arg3.1 in the Cytoplasm and Nucleus of Living Cells. ACS Chem Neurosci 2022; 13:876-882. [PMID: 35319179 DOI: 10.1021/acschemneuro.1c00744] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Arc, also known as Arg3.1, is an activity-dependent immediate-early gene product that plays essential roles in memory consolidation. A pool of Arc is located in the postsynaptic cytoplasm, where it promotes AMPA receptor endocytosis and cytoskeletal remodeling. However, Arc is also found in the nucleus, with a major portion being associated with promyelocytic leukemia nuclear bodies (PML-NBs). Nuclear Arc has been implicated in epigenetic control of gene transcription associated with learning and memory. In this study, we use a battery of fluorescence nanoimaging approaches to characterize the behavior of Arc ectopically expressed in heterologous cells. Our results indicate that in the cytoplasm, Arc exists predominantly as monomers and dimers associated with slowly diffusing particles. In contrast, nuclear Arc is almost exclusively monomeric and displays a higher diffusivity than cytoplasmic Arc. We further show that Arc moves freely and rapidly between PML-NBs and the nucleoplasm and that its movement within PML-NBs is relatively unobstructed.
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Affiliation(s)
- Per Niklas Hedde
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, 651 Ilalo Street, BSB 222, University of Hawaii, Honolulu, Hawaii 96813, United States
| | - Barbara Barylko
- Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park, Dallas, Texas 75390, United States
| | - Derk D. Binns
- Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park, Dallas, Texas 75390, United States
| | - David M. Jameson
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, 651 Ilalo Street, BSB 222, University of Hawaii, Honolulu, Hawaii 96813, United States
| | - Joseph P. Albanesi
- Department of Pharmacology, University of Texas Southwestern Medical Center, 6001 Forest Park, Dallas, Texas 75390, United States
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11
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Ha T, Kaiser C, Myong S, Wu B, Xiao J. Next generation single-molecule techniques: Imaging, labeling, and manipulation in vitro and in cellulo. Mol Cell 2022; 82:304-314. [PMID: 35063098 DOI: 10.1016/j.molcel.2021.12.019] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 12/14/2021] [Accepted: 12/14/2021] [Indexed: 12/24/2022]
Abstract
Owing to their unique abilities to manipulate, label, and image individual molecules in vitro and in cellulo, single-molecule techniques provide previously unattainable access to elementary biological processes. In imaging, single-molecule fluorescence resonance energy transfer (smFRET) and protein-induced fluorescence enhancement in vitro can report on conformational changes and molecular interactions, single-molecule pull-down (SiMPull) can capture and analyze the composition and function of native protein complexes, and single-molecule tracking (SMT) in live cells reveals cellular structures and dynamics. In labeling, the abilities to specifically label genomic loci, mRNA, and nascent polypeptides in cells have uncovered chromosome organization and dynamics, transcription and translation dynamics, and gene expression regulation. In manipulation, optical tweezers, integration of single-molecule fluorescence with force measurements, and single-molecule force probes in live cells have transformed our mechanistic understanding of diverse biological processes, ranging from protein folding, nucleic acids-protein interactions to cell surface receptor function.
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Affiliation(s)
- Taekjip Ha
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Howard Hughes Medical Institute, Baltimore, MD 21205, USA.
| | - Christian Kaiser
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Sua Myong
- Department of Biophysics, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Jie Xiao
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
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12
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Srinivasan B, Samaddar S, Mylavarapu SVS, Clement JP, Banerjee S. Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling. PLoS Biol 2021; 19:e3001432. [PMID: 34813590 PMCID: PMC8610276 DOI: 10.1371/journal.pbio.3001432] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/30/2021] [Indexed: 01/17/2023] Open
Abstract
Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3' UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity.
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Affiliation(s)
| | | | | | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
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13
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mRNA Trafficking in the Nervous System: A Key Mechanism of the Involvement of Activity-Regulated Cytoskeleton-Associated Protein (Arc) in Synaptic Plasticity. Neural Plast 2021; 2021:3468795. [PMID: 34603440 PMCID: PMC8486535 DOI: 10.1155/2021/3468795] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 08/15/2021] [Accepted: 09/07/2021] [Indexed: 12/18/2022] Open
Abstract
Synaptic activity mediates information storage and memory consolidation in the brain and requires a fast de novo synthesis of mRNAs in the nucleus and proteins in synapses. Intracellular localization of a protein can be achieved by mRNA trafficking and localized translation. Activity-regulated cytoskeleton-associated protein (Arc) is a master regulator of synaptic plasticity and plays an important role in controlling large signaling networks implicated in learning, memory consolidation, and behavior. Transcription of the Arc gene may be induced by a short behavioral event, resulting in synaptic activation. Arc mRNA is exported into the cytoplasm and can be trafficked into the dendrite of an activated synapse where it is docked and translated. The structure of Arc is similar to the viral GAG (group-specific antigen) protein, and phylogenic analysis suggests that Arc may originate from the family of Ty3/Gypsy retrotransposons. Therefore, Arc might evolve through “domestication” of retroviruses. Arc can form a capsid-like structure that encapsulates a retrovirus-like sentence in the 3′-UTR (untranslated region) of Arc mRNA. Such complex can be loaded into extracellular vesicles and transported to other neurons or muscle cells carrying not only genetic information but also regulatory signals within neuronal networks. Therefore, Arc mRNA inter- and intramolecular trafficking is essential for the modulation of synaptic activity required for memory consolidation and cognitive functions. Recent studies with single-molecule imaging in live neurons confirmed and extended the role of Arc mRNA trafficking in synaptic plasticity.
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14
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Broix L, Turchetto S, Nguyen L. Coordination between Transport and Local Translation in Neurons. Trends Cell Biol 2021; 31:372-386. [PMID: 33526339 DOI: 10.1016/j.tcb.2021.01.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Revised: 12/31/2020] [Accepted: 01/04/2021] [Indexed: 11/15/2022]
Abstract
The axonal microtubules (MTs) support long-distance transport of cargoes that are dispatched to distinct cellular subcompartments. Among them, mRNAs are directly transported in membraneless ribonucleoprotein (RNP) granules that, together with ribosomes, can also hitchhike on fast-moving membrane-bound organelles for accurate transport along MTs. These organelles serve as platforms for mRNA translation, thus generating axonal foci of newly synthesized proteins. Local translation along axons not only supports MT network integrity but also modulates the processivity and function of molecular motors to allow proper trafficking of cargoes along MTs. Thus, identifying the mechanisms that coordinate axonal transport with local protein synthesis will shed new light on the processes underlying axon development and maintenance, whose deregulation often contribute to neurological disorders.
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Affiliation(s)
- Loïc Broix
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Silvia Turchetto
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium
| | - Laurent Nguyen
- GIGA Stem Cells, GIGA-Neurosciences, University of Liège, C.H.U. Sart Tilman, Liège 4000, Belgium.
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15
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Gobbo F, Cattaneo A. Neuronal Activity at Synapse Resolution: Reporters and Effectors for Synaptic Neuroscience. Front Mol Neurosci 2020; 13:572312. [PMID: 33192296 PMCID: PMC7609880 DOI: 10.3389/fnmol.2020.572312] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/31/2020] [Indexed: 12/15/2022] Open
Abstract
The development of methods for the activity-dependent tagging of neurons enabled a new way to tackle the problem of engram identification at the cellular level, giving rise to groundbreaking findings in the field of memory studies. However, the resolution of activity-dependent tagging remains limited to the whole-cell level. Notably, events taking place at the synapse level play a critical role in the establishment of new memories, and strong experimental evidence shows that learning and synaptic plasticity are tightly linked. Here, we provide a comprehensive review of the currently available techniques that enable to identify and track the neuronal activity with synaptic spatial resolution. We also present recent technologies that allow to selectively interfere with specific subsets of synapses. Lastly, we discuss how these technologies can be applied to the study of learning and memory.
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Affiliation(s)
- Francesco Gobbo
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Antonino Cattaneo
- Bio@SNS Laboratory of Biology, Scuola Normale Superiore, Pisa, Italy
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16
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Kiltschewskij DJ, Cairns MJ. Transcriptome-Wide Analysis of Interplay between mRNA Stability, Translation and Small RNAs in Response to Neuronal Membrane Depolarization. Int J Mol Sci 2020; 21:ijms21197086. [PMID: 32992958 PMCID: PMC7582590 DOI: 10.3390/ijms21197086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/19/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023] Open
Abstract
Experience-dependent changes to neural circuitry are shaped by spatially-restricted activity-dependent mRNA translation. Although the complexity of mRNA translation in neuronal cells is widely appreciated, translational profiles associated with neuronal excitation remain largely uncharacterized, and the associated regulatory mechanisms are poorly understood. Here, we employed ribosome profiling, mRNA sequencing and small RNA sequencing to profile transcriptome-wide changes in mRNA translation after whole cell depolarization of differentiated neuroblast cultures, and investigate the contribution of sequence-specific regulatory mechanisms. Immediately after depolarization, a functional partition between transcriptional and translational responses was uncovered, in which many mRNAs were subjected to significant changes in abundance or ribosomal occupancy, but not both. After an extended (2 h) post-stimulus rest phase, however, these changes became synchronized, suggesting that there are different layers of post-transcriptional regulation which are temporally separated but become coordinated over time. Globally, changes in mRNA abundance and translation were found to be associated with a number of intrinsic mRNA features, including mRNA length, GC% and secondary structures; however, the effect of these factors differed between both post-depolarization time-points. Furthermore, small RNA sequencing revealed that miRNAs and tRNA-derived small RNA fragments were subjected to peak changes in expression immediately after stimulation, during which these molecules were predominantly associated with fluctuations in mRNA abundance, consistent with known regulatory mechanisms. These data suggest that excitation-associated neuronal translation is subjected to extensive temporal coordination, with substantial contributions from a number of sequence-dependent regulatory mechanisms.
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Affiliation(s)
- Dylan J. Kiltschewskij
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan 2308, Australia;
- Centre for Brain and Mental Health Research, Hunter Medical Research Institute, New Lambton 2305, Australia
| | - Murray J. Cairns
- School of Biomedical Sciences and Pharmacy, University of Newcastle, Callaghan 2308, Australia;
- Centre for Brain and Mental Health Research, Hunter Medical Research Institute, New Lambton 2305, Australia
- Schizophrenia Research Institute, Randwick 2031, Australia
- Correspondence: ; Tel.: +61-02-4921-8670
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17
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Zhang H, Bramham CR. Arc/Arg3.1 function in long-term synaptic plasticity: Emerging mechanisms and unresolved issues. Eur J Neurosci 2020; 54:6696-6712. [PMID: 32888346 DOI: 10.1111/ejn.14958] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 07/18/2020] [Accepted: 08/14/2020] [Indexed: 02/06/2023]
Abstract
Arc (activity-regulated cytoskeleton-associated protein) is posited as a critical regulator of long-term synaptic plasticity at excitatory synapses, including long-term potentiation, long-term depression, inverse synaptic tagging and homoeostatic scaling, with pivotal roles in memory and postnatal cortical development. However, the mechanisms underlying the bidirectional regulation of synaptic strength are poorly understood. Here we review evidence from different plasticity paradigms, highlight outstanding issues and discuss stimulus-specific mechanisms that dictate Arc function. We propose a model in which Arc bidirectionally controls synaptic strength by coordinate regulation of AMPA-type glutamate receptor (AMPAR) trafficking and actin cytoskeletal dynamics in dendritic spines. Key to this model, Arc is proposed to function as an activity-dependent regulator of AMPAR lateral membrane diffusion and trapping at synapses.
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Affiliation(s)
- Hongyu Zhang
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Clive R Bramham
- Department of Biomedicine, University of Bergen, Bergen, Norway
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18
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Enam SU, Zinshteyn B, Goldman DH, Cassani M, Livingston NM, Seydoux G, Green R. Puromycin reactivity does not accurately localize translation at the subcellular level. eLife 2020; 9:e60303. [PMID: 32844748 PMCID: PMC7490009 DOI: 10.7554/elife.60303] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/22/2020] [Indexed: 12/16/2022] Open
Abstract
Puromycin is a tyrosyl-tRNA mimic that blocks translation by labeling and releasing elongating polypeptide chains from translating ribosomes. Puromycin has been used in molecular biology research for decades as a translation inhibitor. The development of puromycin antibodies and derivatized puromycin analogs has enabled the quantification of active translation in bulk and single-cell assays. More recently, in vivo puromycylation assays have become popular tools for localizing translating ribosomes in cells. These assays often use elongation inhibitors to purportedly inhibit the release of puromycin-labeled nascent peptides from ribosomes. Using in vitro and in vivo experiments in various eukaryotic systems, we demonstrate that, even in the presence of elongation inhibitors, puromycylated peptides are released and diffuse away from ribosomes. Puromycylation assays reveal subcellular sites, such as nuclei, where puromycylated peptides accumulate post-release and which do not necessarily coincide with sites of active translation. Our findings urge caution when interpreting puromycylation assays in vivo.
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Affiliation(s)
- Syed Usman Enam
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
| | - Boris Zinshteyn
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
| | - Daniel H Goldman
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
| | - Madeline Cassani
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
| | - Nathan M Livingston
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Geraldine Seydoux
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
| | - Rachel Green
- Department of Molecular Biology and Genetics, Johns Hopkins University School of MedicineBaltimoreUnited States
- Howard Hughes Medical InstituteBaltimoreUnited States
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19
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Lottes EN, Cox DN. Homeostatic Roles of the Proteostasis Network in Dendrites. Front Cell Neurosci 2020; 14:264. [PMID: 33013325 PMCID: PMC7461941 DOI: 10.3389/fncel.2020.00264] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 07/28/2020] [Indexed: 12/13/2022] Open
Abstract
Cellular protein homeostasis, or proteostasis, is indispensable to the survival and function of all cells. Distinct from other cell types, neurons are long-lived, exhibiting architecturally complex and diverse multipolar projection morphologies that can span great distances. These properties present unique demands on proteostatic machinery to dynamically regulate the neuronal proteome in both space and time. Proteostasis is regulated by a distributed network of cellular processes, the proteostasis network (PN), which ensures precise control of protein synthesis, native conformational folding and maintenance, and protein turnover and degradation, collectively safeguarding proteome integrity both under homeostatic conditions and in the contexts of cellular stress, aging, and disease. Dendrites are equipped with distributed cellular machinery for protein synthesis and turnover, including dendritically trafficked ribosomes, chaperones, and autophagosomes. The PN can be subdivided into an adaptive network of three major functional pathways that synergistically govern protein quality control through the action of (1) protein synthesis machinery; (2) maintenance mechanisms including molecular chaperones involved in protein folding; and (3) degradative pathways (e.g., Ubiquitin-Proteasome System (UPS), endolysosomal pathway, and autophagy. Perturbations in any of the three arms of proteostasis can have dramatic effects on neurons, especially on their dendrites, which require tightly controlled homeostasis for proper development and maintenance. Moreover, the critical importance of the PN as a cell surveillance system against protein dyshomeostasis has been highlighted by extensive work demonstrating that the aggregation and/or failure to clear aggregated proteins figures centrally in many neurological disorders. While these studies demonstrate the relevance of derangements in proteostasis to human neurological disease, here we mainly review recent literature on homeostatic developmental roles the PN machinery plays in the establishment, maintenance, and plasticity of stable and dynamic dendritic arbors. Beyond basic housekeeping functions, we consider roles of PN machinery in protein quality control mechanisms linked to dendritic plasticity (e.g., dendritic spine remodeling during LTP); cell-type specificity; dendritic morphogenesis; and dendritic pruning.
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Affiliation(s)
- Erin N Lottes
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
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20
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Heterogeneity in mRNA Translation. Trends Cell Biol 2020; 30:606-618. [DOI: 10.1016/j.tcb.2020.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/23/2020] [Accepted: 04/30/2020] [Indexed: 11/18/2022]
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21
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Sending messages in moving cells: mRNA localization and the regulation of cell migration. Essays Biochem 2020; 63:595-606. [PMID: 31324705 DOI: 10.1042/ebc20190009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 07/05/2019] [Accepted: 07/09/2019] [Indexed: 12/13/2022]
Abstract
Cell migration is a fundamental biological process involved in tissue formation and homeostasis. The correct polarization of motile cells is critical to ensure directed movement, and is orchestrated by many intrinsic and extrinsic factors. Of these, the subcellular distribution of mRNAs and the consequent spatial control of translation are key modulators of cell polarity. mRNA transport is dependent on cis-regulatory elements within transcripts, which are recognized by trans-acting proteins that ensure the efficient delivery of certain messages to the leading edge of migrating cells. At their destination, translation of localized mRNAs then participates in regional cellular responses underlying cell motility. In this review, we summarize the key findings that established mRNA targetting as a critical driver of cell migration and how the characterization of polarized mRNAs in motile cells has been expanded from just a few species to hundreds of transcripts. We also describe the molecular control of mRNA trafficking, subsequent mechanisms of local protein synthesis and how these ultimately regulate cell polarity during migration.
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22
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Role of the TRPC1 Channel in Hippocampal Long-Term Depression and in Spatial Memory Extinction. Int J Mol Sci 2020; 21:ijms21051712. [PMID: 32138218 PMCID: PMC7084652 DOI: 10.3390/ijms21051712] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 02/21/2020] [Accepted: 02/27/2020] [Indexed: 12/19/2022] Open
Abstract
Group I metabotropic glutamate receptors (mGluR) are involved in various forms of synaptic plasticity that are believed to underlie declarative memory. We previously showed that mGluR5 specifically activates channels containing TRPC1, an isoform of the canonical family of Transient Receptor Potential channels highly expressed in the CA1-3 regions of the hippocampus. Using a tamoxifen-inducible conditional knockout model, we show here that the acute deletion of the Trpc1 gene alters the extinction of spatial reference memory. mGluR-induced long-term depression, which is partially responsible for memory extinction, was impaired in these mice. Similar results were obtained in vitro and in vivo by inhibiting the channel by its most specific inhibitor, Pico145. Among the numerous known postsynaptic pathways activated by type I mGluR, we observed that the deletion of Trpc1 impaired the activation of ERK1/2 and the subsequent expression of Arc, an immediate early gene that plays a key role in AMPA receptors endocytosis and subsequent long-term depression.
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23
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MicroRNA-34a Acutely Regulates Synaptic Efficacy in the Adult Dentate Gyrus In Vivo. Mol Neurobiol 2019; 57:1432-1445. [PMID: 31754996 DOI: 10.1007/s12035-019-01816-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 10/11/2019] [Indexed: 12/30/2022]
Abstract
Activity-dependent synaptic plasticity involves rapid regulation of neuronal protein synthesis on a time-scale of minutes. miRNA function in synaptic plasticity and memory formation has been elucidated by stable experimental manipulation of miRNA expression and activity using transgenic approaches and viral vectors. However, the impact of rapid miRNA modulation on synaptic efficacy is unknown. Here, we examined the effect of acute (12 min), intrahippocampal infusion of a miR-34a antagonist (antimiR) on medial perforant path-evoked synaptic transmission in the dentate gyrus of adult anesthetised rats. AntimiR-34a infusion acutely depressed medial perforant path-evoked field excitatory post-synaptic potentials (fEPSPs). The fEPSP decrease was detected within 9 min of infusion, lasted for hours, and was associated with knockdown of antimiR-34a levels. AntimiR-34a-induced synaptic depression was sequence-specific; no changes were elicited by infusion of scrambled or mismatch control. The rapid modulation suggests that a target, or set of targets, is regulated by miR-34a. Western blot analysis of dentate gyrus lysates revealed enhanced expression of Arc, a known miR-34a target, and four novel predicted targets (Ctip2, PKI-1α, TCF4 and Ube2g1). Remarkably, antimiR-34a had no effect when infused during the maintenance phase of long-term potentiation. We conclude that miR-34a regulates basal synaptic efficacy in the adult dentate gyrus in vivo. To our knowledge, these in vivo findings are the first to demonstrate acute (< 9 min) regulation of synaptic efficacy in the adult brain by a miRNA.
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24
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Langille JJ, Ginzberg K, Sossin WS. Polysomes identified by live imaging of nascent peptides are stalled in hippocampal and cortical neurites. ACTA ACUST UNITED AC 2019; 26:351-362. [PMID: 31416908 PMCID: PMC6699411 DOI: 10.1101/lm.049965.119] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/10/2019] [Indexed: 12/18/2022]
Abstract
In neurons, mRNAs can be repressed postinitiation and assembled into granules enabling the transport and later, regulated reactivation of the paused mRNAs. It has been suggested that a large percentage of transcripts in neuronal processes are stored in these stalled polysomes. Given this, it is predicted that nascent peptides should be abundant in these granules. Nascent peptides can be visualized in real time by the SunTag system. Using this system, we observe nascent peptides in neuronal processes that are resistant to runoff with the initiation inhibitor homoharringtonin (HHT) and to release by puromycin, properties expected from RNA granules consisting of stalled polysomes. In contrast, nascent peptides in nonneuronal cells and neuronal cell bodies were not resistant to HHT or puromycin. Stalled polysomes can also be visualized after runoff with ribopuromycylation and the RNA granules imaged with ribopuromycylation were the same as those with SunTag visualized nascent peptides. Accordingly, the ribopuromycylated puncta in neuronal dendrites were also resistant to puromycin. Thus, the SunTag technique corroborates in situ evidence of stalled polysomes and will allow for the live examination of these translational structures as a mechanism for mRNA transport and regulated protein synthesis.
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Affiliation(s)
- Jesse J Langille
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
| | - Keren Ginzberg
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
| | - Wayne S Sossin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal H3A-2B4, Quebec, Canada
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25
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Livingstone RW, Elder MK, Barrett MC, Westlake CM, Peppercorn K, Tate WP, Abraham WC, Williams JM. Secreted Amyloid Precursor Protein-Alpha Promotes Arc Protein Synthesis in Hippocampal Neurons. Front Mol Neurosci 2019; 12:198. [PMID: 31474829 PMCID: PMC6702288 DOI: 10.3389/fnmol.2019.00198] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 07/30/2019] [Indexed: 12/22/2022] Open
Abstract
Secreted amyloid precursor protein-α (sAPPα) is a neuroprotective and memory-enhancing molecule, however, the mechanisms through which sAPPα promotes these effects are not well understood. Recently, we have shown that sAPPα enhances cell-surface expression of glutamate receptors. Activity-related cytoskeletal-associated protein Arc (Arg3.1) is an immediate early gene capable of modulating long-term potentiation, long-term depression and homeostatic plasticity through regulation of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor localization. Accordingly, we hypothesized that sAPPα may enhance synaptic plasticity, in part, by the de novo synthesis of Arc. Using primary cortical and hippocampal neuronal cultures we found that sAPPα (1 nM, 2 h) enhances levels of Arc mRNA and protein. Arc protein levels were increased in both the neuronal somata and dendrites in a Ca2+/calmodulin-dependent protein kinase II-dependent manner. Additionally, dendritic Arc expression was dependent upon activation of mitogen-activated protein kinase and protein kinase G. The enhancement of dendritic Arc protein was significantly reduced by antagonism of N-methyl-D-aspartate (NMDA) and nicotinic acetylcholine (α7nACh) receptors, and fully eliminated by dual application of these antagonists. This effect was further corroborated in area CA1 of acute hippocampal slices. These data suggest sAPPα-regulated plasticity within hippocampal neurons is mediated by cooperation of NMDA and α7nACh receptors to engage a cascade of signal transduction molecules to enhance the transcription and translation of Arc.
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Affiliation(s)
- Rhys W Livingstone
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Megan K Elder
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Maya C Barrett
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Courteney M Westlake
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Katie Peppercorn
- Department of Biochemistry, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Warren P Tate
- Department of Biochemistry, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Wickliffe C Abraham
- Department of Psychology, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Joanna M Williams
- Department of Anatomy, Brain Health Research Centre, Brain Research New Zealand, Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
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26
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Zhang W, Chuang YA, Na Y, Ye Z, Yang L, Lin R, Zhou J, Wu J, Qiu J, Savonenko A, Leahy DJ, Huganir R, Linden DJ, Worley PF. Arc Oligomerization Is Regulated by CaMKII Phosphorylation of the GAG Domain: An Essential Mechanism for Plasticity and Memory Formation. Mol Cell 2019; 75:13-25.e5. [PMID: 31151856 DOI: 10.1016/j.molcel.2019.05.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/27/2019] [Accepted: 05/01/2019] [Indexed: 12/17/2022]
Abstract
Arc is a synaptic protein essential for memory consolidation. Recent studies indicate that Arc originates in evolution from a Ty3-Gypsy retrotransposon GAG domain. The N-lobe of Arc GAG domain acquired a hydrophobic binding pocket in higher vertebrates that is essential for Arc's canonical function to weaken excitatory synapses. Here, we report that Arc GAG also acquired phosphorylation sites that can acutely regulate its synaptic function. CaMKII phosphorylates the N-lobe of the Arc GAG domain and disrupts an interaction surface essential for high-order oligomerization. In Purkinje neurons, CaMKII phosphorylation acutely reverses Arc's synaptic action. Mutant Arc that cannot be phosphorylated by CaMKII enhances metabotropic receptor-dependent depression in the hippocampus but does not alter baseline synaptic transmission or long-term potentiation. Behavioral studies indicate that hippocampus- and amygdala-dependent learning requires Arc GAG domain phosphorylation. These studies provide an atomic model for dynamic and local control of Arc function underlying synaptic plasticity and memory.
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Affiliation(s)
- Wenchi Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yang-An Chuang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Youn Na
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zengyou Ye
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Liuqing Yang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Raozhou Lin
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiechao Zhou
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jing Wu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jessica Qiu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Alena Savonenko
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel J Leahy
- Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Richard Huganir
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - David J Linden
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Paul F Worley
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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Cai M, Zhu Y, Li Z, Josephs-Spaulding J, Zhou Y, Hu Y, Chen H, Liu Y, He W, Zhang J. Profiling the Gene Expression and DNA Methylation in the Mouse Brain after Ischemic Preconditioning. Neuroscience 2019; 406:249-261. [DOI: 10.1016/j.neuroscience.2019.03.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 03/09/2019] [Accepted: 03/11/2019] [Indexed: 01/27/2023]
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28
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Fluorescence Imaging Methods to Investigate Translation in Single Cells. Cold Spring Harb Perspect Biol 2019; 11:cshperspect.a032722. [PMID: 30082468 DOI: 10.1101/cshperspect.a032722] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Translation is the fundamental biological process that converts the genetic information in messenger RNAs (mRNAs) into functional proteins. Translation regulation allows cells to control when, where, and how many proteins are synthesized. Much of what we know about translation comes from ensemble approaches that measure the average of many cells. The cellular and molecular heterogeneity in the regulation of translation remains largely elusive. Fluorescence microscopy allows interrogation of biological problems with single-molecule, single-cell sensitivity. In recent years, improved design of reagents and microscopy tools has led to improved spatial and temporal resolution of translation imaging. It is now possible to track global translation in specific subcellular compartments and follow the translation dynamics of single transcripts. Highlighted here is the recent progress in translation imaging with emphasis on in vivo translation dynamics. These tools will be invaluable to the study of translation regulation.
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29
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Biever A, Donlin-Asp PG, Schuman EM. Local translation in neuronal processes. Curr Opin Neurobiol 2019; 57:141-148. [PMID: 30861464 DOI: 10.1016/j.conb.2019.02.008] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 02/07/2019] [Indexed: 12/19/2022]
Abstract
Neurons exhibit a unique degree of spatial compartmentalization and are able to maintain and remodel their proteomes independently from the cell body. While much effort has been devoted to understanding the capacity and role for local protein synthesis in dendrites and spines, local mRNA translation in mature axons, projecting over distances up to a meter, has received much less attention. Also, little is known about the spatio-temporal dynamics of axonal and dendritic gene expression as function of mRNA abundance, protein synthesis and degradation. Here, we summarize key recent findings that have shaped our knowledge of the precise location of local protein production and discuss unique strategies used by neurons to shape presynaptic and postsynaptic proteomes.
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Affiliation(s)
- Anne Biever
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | | | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
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30
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Izumi H, Ishimoto T, Yamamoto H, Mori H. Bioluminescence imaging of Arc expression in mouse brain under acute and chronic exposure to pesticides. Neurotoxicology 2019; 71:52-59. [DOI: 10.1016/j.neuro.2018.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/27/2018] [Accepted: 12/13/2018] [Indexed: 11/28/2022]
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31
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The Arc gene: Retroviral heritage in cognitive functions. Neurosci Biobehav Rev 2019; 99:275-281. [PMID: 30772431 DOI: 10.1016/j.neubiorev.2019.02.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Revised: 01/29/2019] [Accepted: 02/12/2019] [Indexed: 12/22/2022]
Abstract
Stabilization of neuronal plastic changes is mediated by transient gene expression, including transcription of the activity-regulated cytoskeleton-associated gene (Arc), also known as Arg 3.1. Arc is implicated in several types of synaptic plasticity, including synaptic scaling, long-term potentiation, and long-term depression. However, the precise mechanisms by which Arc mediates these forms of long-term plasticity are unclear. It was recently found that Arc protein is capable of forming capsid-like structures and of transferring its own mRNA to neighboring cells. Moreover, Arc mRNA undergoes activity-dependent translation in these "transfected" cells. These new data raise unexpected possibilities for the mechanisms of the Arc action, and many intriguing questions concerning the role of Arc transcellular traffic in neuronal plasticity. In this mini-review, we discuss a possible link between the role of Arc in learning and memory and the virus-like properties of this protein. Additionally, we highlight some of the emerging questions for future neurobiological studies and translational applications of Arc transsynaptic effects.
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32
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Abstract
Alzheimer's disease (AD) dementia refers to a particular onset and course of cognitive and functional decline associated with age together with a particular neuropathology. It was first described by Alois Alzheimer in 1906 about a patient whom he first encountered in 1901. Modern clinical diagnostic criteria have been developed, and criteria have also been proposed to recognize preclinical (or presymptomatic) stages of the disease with the use of biomarkers. The primary neuropathology was described by Alzheimer, and in the mid-1980s subsequently evolved into a more specific neuropathologic definition that recognizes the comorbid neuropathologies that frequently contribute to clinical dementia. Alzheimer's disease is now the most common form of neurodegenerative dementia in the United States with a disproportionate disease burden in minority populations. Deficits in the ability to encode and store new memories characterizes the initial stages of the disease. Subsequent progressive changes in cognition and behavior accompany the later stages. Changes in amyloid precursor protein (APP) cleavage and production of the APP fragment beta-amyloid (Aβ) along with hyperphosphorylated tau protein aggregation coalesce to cause reduction in synaptic strength, synaptic loss, and neurodegeneration. Metabolic, vascular, and inflammatory changes, as well as comorbid pathologies are key components of the disease process. Symptomatic treatment offers a modest, clinically measurable effect in cognition, but disease-modifying therapies are desperately needed.
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Affiliation(s)
- Jose A Soria Lopez
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States; Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego, La Jolla, CA, United States
| | - Hector M González
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States; Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego, La Jolla, CA, United States
| | - Gabriel C Léger
- Department of Neurosciences, University of California San Diego, La Jolla, CA, United States; Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego, La Jolla, CA, United States.
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Paolantoni C, Ricciardi S, De Paolis V, Okenwa C, Catalanotto C, Ciotti MT, Cattaneo A, Cogoni C, Giorgi C. Arc 3' UTR Splicing Leads to Dual and Antagonistic Effects in Fine-Tuning Arc Expression Upon BDNF Signaling. Front Mol Neurosci 2018; 11:145. [PMID: 29755318 PMCID: PMC5934489 DOI: 10.3389/fnmol.2018.00145] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 04/10/2018] [Indexed: 01/02/2023] Open
Abstract
Activity-regulated cytoskeletal associated protein (Arc) is an immediate-early gene critically involved in synaptic plasticity and memory consolidation. Arc mRNA is rapidly induced by synaptic activation and a portion is locally translated in dendrites where it modulates synaptic strength. Being an activity-dependent effector of homeostatic balance, regulation of Arc is uniquely tuned to result in short-lived bursts of expression. Cis-Acting elements that control its transitory expression post-transcriptionally reside primarily in Arc mRNA 3′ UTR. These include two conserved introns which distinctively modulate Arc mRNA stability by targeting it for destruction via the nonsense mediated decay pathway. Here, we further investigated how splicing of the Arc mRNA 3′ UTR region contributes to modulate Arc expression in cultured neurons. Unexpectedly, upon induction with brain derived neurotrophic factor, translational efficiency of a luciferase reporter construct harboring Arc 3′ UTR is significantly upregulated and this effect is dependent on splicing of Arc introns. We find that, eIF2α dephosphorylation, mTOR, ERK, PKC, and PKA activity are key to this process. Additionally, CREB-dependent transcription is required to couple Arc 3′ UTR-splicing to its translational upregulation, suggesting the involvement of de novo transcribed trans-acting factors. Overall, splicing of Arc 3′ UTR exerts a dual and unique effect in fine-tuning Arc expression upon synaptic signaling: while inducing mRNA decay to limit the time window of Arc expression, it also elicits translation of the decaying mRNA. This antagonistic effect likely contributes to the achievement of a confined yet efficient burst of Arc protein expression, facilitating its role as an effector of synapse-specific plasticity.
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Affiliation(s)
- Chiara Paolantoni
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy.,Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Simona Ricciardi
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy.,Department of Biology and Biotechnology, Sapienza University of Rome, Rome, Italy
| | - Veronica De Paolis
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy.,Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, Rome, Italy
| | - Chinenye Okenwa
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy
| | - Caterina Catalanotto
- Department of Cellular Biotechnologies and Hematology, Sapienza University of Rome, Rome, Italy
| | - Maria T Ciotti
- Institute of Cell Biology and Neurobiology, National Research Council, Rome, Italy
| | - Antonino Cattaneo
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy.,Bio@SNS Laboratory, Scuola Normale Superiore, Pisa, Italy
| | - Carlo Cogoni
- Department of Cellular Biotechnologies and Hematology, Sapienza University of Rome, Rome, Italy
| | - Corinna Giorgi
- European Brain Research Institute Rita Levi-Montalcini Rome, Rome, Italy
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34
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Ostroff LE, Watson DJ, Cao G, Parker PH, Smith H, Harris KM. Shifting patterns of polyribosome accumulation at synapses over the course of hippocampal long-term potentiation. Hippocampus 2018; 28:416-430. [PMID: 29575288 DOI: 10.1002/hipo.22841] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 02/28/2018] [Accepted: 03/11/2018] [Indexed: 11/09/2022]
Abstract
Hippocampal long-term potentiation (LTP) is a cellular memory mechanism. For LTP to endure, new protein synthesis is required immediately after induction and some of these proteins must be delivered to specific, presumably potentiated, synapses. Local synthesis in dendrites could rapidly provide new proteins to synapses, but the spatial distribution of translation following induction of LTP is not known. Here, we quantified polyribosomes, the sites of local protein synthesis, in CA1 stratum radiatum dendrites and spines from postnatal day 15 rats. Hippocampal slices were rapidly fixed at 5, 30, or 120 min after LTP induction by theta-burst stimulation (TBS). Dendrites were reconstructed through serial section electron microscopy from comparable regions near the TBS or control electrodes in the same slice, and in unstimulated hippocampus that was perfusion-fixed in vivo. At 5 min after induction of LTP, polyribosomes were elevated in dendritic shafts and spines, especially near spine bases and in spine heads. At 30 min, polyribosomes remained elevated only in spine bases. At 120 min, both spine bases and spine necks had elevated polyribosomes. Polyribosomes accumulated in spines with larger synapses at 5 and 30 min, but not at 120 min. Small spines, meanwhile, proliferated dramatically by 120 min, but these largely lacked polyribosomes. The number of ribosomes per polyribosome is variable and may reflect differences in translation regulation. In dendritic spines, but not shafts, there were fewer ribosomes per polyribosome in the slice conditions relative to in vivo, but this recovered transiently in the 5 min LTP condition. Overall, our data show that LTP induces a rapid, transient upregulation of large polyribosomes in larger spines, and a persistent upregulation of small polyribosomes in the bases and necks of small spines. This is consistent with local translation supporting enlargement of potentiated synapses within minutes of LTP induction.
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Affiliation(s)
- Linnaea E Ostroff
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, Connecticut 06269
| | - Deborah J Watson
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78731
| | - Guan Cao
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78731
| | - Patrick H Parker
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78731
| | - Heather Smith
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78731
| | - Kristen M Harris
- Department of Neuroscience, Center for Learning and Memory, Institute for Neuroscience, University of Texas at Austin, Austin, Texas 78731
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35
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Neuronal RNP granules: from physiological to pathological assemblies. Biol Chem 2018; 399:623-635. [DOI: 10.1515/hsz-2018-0141] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/30/2018] [Indexed: 12/11/2022]
Abstract
Abstract
Neuronal cells rely on macro- and micro-cellular compartmentalization to rapidly process information, and respond locally to external stimuli. Such a cellular organization is achieved via the assembly of neuronal ribonucleoprotein (RNP) granules, dynamic membrane-less organelles enriched in RNAs and associated regulatory proteins. In this review, we discuss how these high-order structures transport mRNAs to dendrites and axons, and how they contribute to the spatio-temporal regulation of localized mRNA translation. We also highlight how recent biophysical studies have shed light on the mechanisms underlying neuronal RNP granule dynamic assembly, remodeling and maturation, in both physiological and pathological contexts.
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36
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Banerjee A, Ifrim MF, Valdez AN, Raj N, Bassell GJ. Aberrant RNA translation in fragile X syndrome: From FMRP mechanisms to emerging therapeutic strategies. Brain Res 2018; 1693:24-36. [PMID: 29653083 PMCID: PMC7377270 DOI: 10.1016/j.brainres.2018.04.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 02/07/2023]
Abstract
Research in the past decades has unfolded the multifaceted role of Fragile X mental retardation protein (FMRP) and how its absence contributes to the pathophysiology of Fragile X syndrome (FXS). Excess signaling through group 1 metabotropic glutamate receptors is commonly observed in mouse models of FXS, which in part is attributed to dysregulated translation and downstream signaling. Considering the wide spectrum of cellular and physiologic functions that loss of FMRP can affect in general, it may be advantageous to pursue disease mechanism based treatments that directly target translational components or signaling factors that regulate protein synthesis. Various FMRP targets upstream and downstream of the translational machinery are therefore being investigated to further our understanding of the molecular mechanism of RNA and protein synthesis dysregulation in FXS as well as test their potential role as therapeutic interventions to alleviate FXS associated symptoms. In this review, we will broadly discuss recent advancements made towards understanding the role of FMRP in translation regulation, new pre-clinical animal models with FMRP targets located at different levels of the translational and signal transduction pathways for therapeutic intervention as well as future use of stem cells to model FXS associated phenotypes.
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Affiliation(s)
- Anwesha Banerjee
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.
| | - Marius F Ifrim
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Arielle N Valdez
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Nisha Raj
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA; Department of Neurology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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37
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Synapse development organized by neuronal activity-regulated immediate-early genes. Exp Mol Med 2018; 50:1-7. [PMID: 29628504 PMCID: PMC5938016 DOI: 10.1038/s12276-018-0025-1] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2017] [Accepted: 11/29/2017] [Indexed: 02/07/2023] Open
Abstract
Classical studies have shown that neuronal immediate-early genes (IEGs) play important roles in synaptic processes critical for key brain functions. IEGs are transiently activated and rapidly upregulated in discrete neurons in response to a wide variety of cellular stimuli, and they are uniquely involved in various aspects of synapse development. In this review, we summarize recent studies of a subset of neuronal IEGs in regulating synapse formation, transmission, and plasticity. We also discuss how the dysregulation of neuronal IEGs is associated with the onset of various brain disorders and pinpoint key outstanding questions that should be addressed in this field. Immediate-early genes (IEGs), genes that are rapidly and transiently activated by cellular stimuli, regulate the interactions between neurons and key brain functions. Ji Won Um and colleagues at Daegu Gyeongbuk Institute of Science and Technology in South Korea review recent studies on three IEGs that are activated by neuronal activity and highlight their contribution to neuronal excitability and cognitive behaviors. These genes rely on different molecular mechanisms to regulate neuronal receptors and the structure of synapses. Research in mice lacking any one of these IEGs reveals their contribution to learning and memory as well as to some behavioral abnormalities associated with neuropsychiatric disorders. Further research into the activity of IEGs will advance our understanding of how a neuron’s environment influences brain development and disease.
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38
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Mazzoni-Putman SM, Stepanova AN. A Plant Biologist's Toolbox to Study Translation. FRONTIERS IN PLANT SCIENCE 2018; 9:873. [PMID: 30013583 PMCID: PMC6036148 DOI: 10.3389/fpls.2018.00873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/04/2018] [Indexed: 05/03/2023]
Abstract
Across a broad range of species and biological questions, more and more studies are incorporating translation data to better assess how gene regulation occurs at the level of protein synthesis. The inclusion of translation data improves upon, and has been shown to be more accurate than, transcriptional studies alone. However, there are many different techniques available to measure translation and it can be difficult, especially for young or aspiring scientists, to determine which methods are best applied in specific situations. We have assembled this review in order to enhance the understanding and promote the utilization of translational methods in plant biology. We cover a broad range of methods to measure changes in global translation (e.g., radiolabeling, polysome profiling, or puromycylation), translation of single genes (e.g., fluorescent reporter constructs, toeprinting, or ribosome density mapping), sequencing-based methods to uncover the entire translatome (e.g., Ribo-seq or translating ribosome affinity purification), and mass spectrometry-based methods to identify changes in the proteome (e.g., stable isotope labeling by amino acids in cell culture or bioorthogonal noncanonical amino acid tagging). The benefits and limitations of each method are discussed with a particular note of how applications from other model systems might be extended for use in plants. In order to make this burgeoning field more accessible to students and newer scientists, our review includes an extensive glossary to define key terms.
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39
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Wilkerson JR, Albanesi JP, Huber KM. Roles for Arc in metabotropic glutamate receptor-dependent LTD and synapse elimination: Implications in health and disease. Semin Cell Dev Biol 2017; 77:51-62. [PMID: 28969983 DOI: 10.1016/j.semcdb.2017.09.035] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/21/2017] [Accepted: 09/26/2017] [Indexed: 10/18/2022]
Abstract
The Arc gene is robustly transcribed in specific neural ensembles in response to experience-driven activity. Upon induction, Arc mRNA is transported to dendrites, where it can be rapidly and locally translated by activation of metabotropic glutamate receptors (mGluR1/5). mGluR-induced dendritic synthesis of Arc is implicated in weakening or elimination of excitatory synapses by triggering endocytosis of postsynaptic AMPARs in both hippocampal CA1 and cerebellar Purkinje neurons. Importantly, CA1 neurons with experience-induced Arc mRNA are susceptible, or primed for mGluR-induced long-term synaptic depression (mGluR-LTD). Here we review mechanisms and function of Arc in mGluR-LTD and synapse elimination and propose roles for these forms of plasticity in Arc-dependent formation of sparse neural representations of learned experience. We also discuss accumulating evidence linking dysregulation of Arc and mGluR-LTD in human cognitive disorders such as intellectual disability, autism and Alzheimer's disease.
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Affiliation(s)
- Julia R Wilkerson
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Joseph P Albanesi
- Departments of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States
| | - Kimberly M Huber
- Departments of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX 75390, United States.
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40
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Okuno H, Minatohara K, Bito H. Inverse synaptic tagging: An inactive synapse-specific mechanism to capture activity-induced Arc/arg3.1 and to locally regulate spatial distribution of synaptic weights. Semin Cell Dev Biol 2017; 77:43-50. [PMID: 28939038 DOI: 10.1016/j.semcdb.2017.09.025] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 09/15/2017] [Accepted: 09/18/2017] [Indexed: 12/22/2022]
Abstract
Long-lasting forms of synaptic plasticity such as long-term potentiation (LTP) and long-term depression (LTD) are fundamental cellular mechanisms underlying learning and memory. The synaptic tagging and capture (STC) hypothesis has provided a theoretical framework on how products of activity-dependent genes may interact with potentiated synapses to facilitate and maintain such long-lasting synaptic plasticity. Although Arc/arg3.1 was initially assumed to participate in STC processes during LTP, accumulating evidence indicated that Arc/arg3.1 might rather contribute in weakening of synaptic weights than in their strengthening. In particular, analyses of Arc/Arg3.1 protein dynamics and function in the dendrites after plasticity-inducing stimuli have revealed a new type of inactivity-dependent redistribution of synaptic weights, termed "inverse synaptic tagging". The original synaptic tagging and inverse synaptic tagging likely co-exist and are mutually non-exclusive mechanisms, which together may help orchestrate the redistribution of synaptic weights and promote the enhancement and maintenance of their contrast between potentiated and non-potentiated synapses during the late phase of long-term synaptic plasticity. In this review, we describe the inverse synaptic tagging mechanism that controls synaptic dynamics of Arc/Arg3.1, an immediate early gene product which is captured and preferentially targeted to non-potentiated synapses, and discuss its impact on neuronal circuit refinement and cognitive function.
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Affiliation(s)
- Hiroyuki Okuno
- SK Project, Medical Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
| | - Keiichiro Minatohara
- SK Project, Medical Innovation Center, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Haruhiko Bito
- Department of Neurochemistry, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
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41
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Evans AJ, Gurung S, Wilkinson KA, Stephens DJ, Henley JM. Assembly, Secretory Pathway Trafficking, and Surface Delivery of Kainate Receptors Is Regulated by Neuronal Activity. Cell Rep 2017; 19:2613-2626. [PMID: 28636947 PMCID: PMC5489663 DOI: 10.1016/j.celrep.2017.06.001] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Revised: 04/17/2017] [Accepted: 05/25/2017] [Indexed: 01/03/2023] Open
Abstract
Ionotropic glutamate receptor (iGluR) trafficking and function underpin excitatory synaptic transmission and plasticity and shape neuronal networks. It is well established that the transcription, translation, and endocytosis/recycling of iGluRs are all regulated by neuronal activity, but much less is known about the activity dependence of iGluR transport through the secretory pathway. Here, we use the kainate receptor subunit GluK2 as a model iGluR cargo to show that the assembly, early secretory pathway trafficking, and surface delivery of iGluRs are all controlled by neuronal activity. We show that the delivery of de novo kainate receptors is differentially regulated by modulation of GluK2 Q/R editing, PKC phosphorylation, and PDZ ligand interactions. These findings reveal that, in addition to short-term regulation of iGluRs by recycling/endocytosis and long-term modulation by altered transcription/translation, the trafficking of iGluRs through the secretory pathway is under tight activity-dependent control to determine the numbers and properties of surface-expressed iGluRs.
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Affiliation(s)
- Ashley J Evans
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Sonam Gurung
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Kevin A Wilkinson
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - David J Stephens
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK
| | - Jeremy M Henley
- School of Biochemistry, Centre for Synaptic Plasticity, Biomedical Sciences Building, University of Bristol, University Walk, Bristol BS8 1TD, UK.
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42
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Abstract
Neurons are amongst the most structurally complex cells and exhibit a high degree of spatial compartmentalization. Also, neurons exhibit rapid and dynamic signaling by processing information in a precise and, sometimes, spatially-restricted manner. The signaling that occurs in axons and dendrites necessitates the maintenance and modification of their local proteomes. Local translation of mRNAs into protein is one solution that neurons use to meet synaptic demand and activity. Here we review some of the key findings and recent discoveries that have shaped our understanding of local translation in neuronal function and highlight important new techniques that might pave the way for new insights.
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43
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Iwasaki S, Ingolia NT. The Growing Toolbox for Protein Synthesis Studies. Trends Biochem Sci 2017; 42:612-624. [PMID: 28566214 DOI: 10.1016/j.tibs.2017.05.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 04/24/2017] [Accepted: 05/05/2017] [Indexed: 12/29/2022]
Abstract
Protein synthesis stands at the last stage of the central dogma of molecular biology, providing a final regulatory layer for gene expression. Reacting to environmental cues and internal signals, the translation machinery can quickly tune the translatome from a pre-existing pool of RNAs, before the transcriptome changes. Although the translation reaction itself has been known since the 1950s, the quantitative or even qualitative measurement of its efficacy in cells has posed experimental and analytic hurdles. In this review, we outline the array of state-of-the-art methods that have emerged to tackle the hidden aspects of translational control.
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Affiliation(s)
| | - Nicholas T Ingolia
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA.
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44
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LaLumiere RT, McGaugh JL, McIntyre CK. Emotional Modulation of Learning and Memory: Pharmacological Implications. Pharmacol Rev 2017; 69:236-255. [PMID: 28420719 DOI: 10.1124/pr.116.013474] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 03/03/2017] [Indexed: 01/06/2023] Open
Abstract
Memory consolidation involves the process by which newly acquired information becomes stored in a long-lasting fashion. Evidence acquired over the past several decades, especially from studies using post-training drug administration, indicates that emotional arousal during the consolidation period influences and enhances the strength of the memory and that multiple different chemical signaling systems participate in this process. The mechanisms underlying the emotional influences on memory involve the release of stress hormones and activation of the basolateral amygdala, which work together to modulate memory consolidation. Moreover, work suggests that this amygdala-based memory modulation occurs with numerous types of learning and involves interactions with many different brain regions to alter consolidation. Additionally, studies suggest that emotional arousal and amygdala activity in particular influence synaptic plasticity and associated proteins in downstream brain regions. This review considers the historical understanding for memory modulation and cellular consolidation processes and examines several research areas currently using this foundational knowledge to develop therapeutic treatments.
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Affiliation(s)
- Ryan T LaLumiere
- Department of Psychological and Brain Sciences and Interdisciplinary Neuroscience Program, University of Iowa, Iowa City, Iowa (R.T.L.); Department of Neurobiology and Behavior, University of California, Irvine, California (J.L.M.); and School of Behavioral and Brain Sciences, University of Texas-Dallas, Richardson, Texas (C.K.M.)
| | - James L McGaugh
- Department of Psychological and Brain Sciences and Interdisciplinary Neuroscience Program, University of Iowa, Iowa City, Iowa (R.T.L.); Department of Neurobiology and Behavior, University of California, Irvine, California (J.L.M.); and School of Behavioral and Brain Sciences, University of Texas-Dallas, Richardson, Texas (C.K.M.)
| | - Christa K McIntyre
- Department of Psychological and Brain Sciences and Interdisciplinary Neuroscience Program, University of Iowa, Iowa City, Iowa (R.T.L.); Department of Neurobiology and Behavior, University of California, Irvine, California (J.L.M.); and School of Behavioral and Brain Sciences, University of Texas-Dallas, Richardson, Texas (C.K.M.)
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Konietzny A, Bär J, Mikhaylova M. Dendritic Actin Cytoskeleton: Structure, Functions, and Regulations. Front Cell Neurosci 2017; 11:147. [PMID: 28572759 PMCID: PMC5435805 DOI: 10.3389/fncel.2017.00147] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Accepted: 05/05/2017] [Indexed: 12/28/2022] Open
Abstract
Actin is a versatile and ubiquitous cytoskeletal protein that plays a major role in both the establishment and the maintenance of neuronal polarity. For a long time, the most prominent roles that were attributed to actin in neurons were the movement of growth cones, polarized cargo sorting at the axon initial segment, and the dynamic plasticity of dendritic spines, since those compartments contain large accumulations of actin filaments (F-actin) that can be readily visualized using electron- and fluorescence microscopy. With the development of super-resolution microscopy in the past few years, previously unknown structures of the actin cytoskeleton have been uncovered: a periodic lattice consisting of actin and spectrin seems to pervade not only the whole axon, but also dendrites and even the necks of dendritic spines. Apart from that striking feature, patches of F-actin and deep actin filament bundles have been described along the lengths of neurites. So far, research has been focused on the specific roles of actin in the axon, while it is becoming more and more apparent that in the dendrite, actin is not only confined to dendritic spines, but serves many additional and important functions. In this review, we focus on recent developments regarding the role of actin in dendrite morphology, the regulation of actin dynamics by internal and external factors, and the role of F-actin in dendritic protein trafficking.
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Affiliation(s)
- Anja Konietzny
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Julia Bär
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Marina Mikhaylova
- DFG Emmy Noether Group 'Neuronal Protein Transport,' Center for Molecular Neurobiology (ZMNH), University Medical Center Hamburg-EppendorfHamburg, Germany
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Namjoshi SV, Raab-Graham KF. Screening the Molecular Framework Underlying Local Dendritic mRNA Translation. Front Mol Neurosci 2017; 10:45. [PMID: 28286470 PMCID: PMC5323403 DOI: 10.3389/fnmol.2017.00045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Accepted: 02/10/2017] [Indexed: 12/13/2022] Open
Abstract
In the last decade, bioinformatic analyses of high-throughput proteomics and transcriptomics data have enabled researchers to gain insight into the molecular networks that may underlie lasting changes in synaptic efficacy. Development and utilization of these techniques have advanced the field of learning and memory significantly. It is now possible to move from the study of activity-dependent changes of a single protein to modeling entire network changes that require local protein synthesis. This data revolution has necessitated the development of alternative computational and statistical techniques to analyze and understand the patterns contained within. Thus, the focus of this review is to provide a synopsis of the journey and evolution toward big data techniques to address still unanswered questions regarding how synapses are modified to strengthen neuronal circuits. We first review the seminal studies that demonstrated the pivotal role played by local mRNA translation as the mechanism underlying the enhancement of enduring synaptic activity. In the interest of those who are new to the field, we provide a brief overview of molecular biology and biochemical techniques utilized for sample preparation to identify locally translated proteins using RNA sequencing and proteomics, as well as the computational approaches used to analyze these data. While many mRNAs have been identified, few have been shown to be locally synthesized. To this end, we review techniques currently being utilized to visualize new protein synthesis, a task that has proven to be the most difficult aspect of the field. Finally, we provide examples of future applications to test the physiological relevance of locally synthesized proteins identified by big data approaches.
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Affiliation(s)
- Sanjeev V Namjoshi
- Center for Learning and Memory, The University of Texas at Austin, AustinTX, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, AustinTX, USA
| | - Kimberly F Raab-Graham
- Center for Learning and Memory, The University of Texas at Austin, AustinTX, USA; Institute for Cellular and Molecular Biology, The University of Texas at Austin, AustinTX, USA; Department of Physiology and Pharmacology, Wake Forest Health Sciences, Medical Center Boulevard, Winston-SalemNC, USA
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Zhu G, Briz V, Seinfeld J, Liu Y, Bi X, Baudry M. Calpain-1 deletion impairs mGluR-dependent LTD and fear memory extinction. Sci Rep 2017; 7:42788. [PMID: 28202907 PMCID: PMC5311935 DOI: 10.1038/srep42788] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 01/17/2017] [Indexed: 01/02/2023] Open
Abstract
Recent studies indicate that calpain-1 is required for the induction of long-term potentiation (LTP) elicited by theta-burst stimulation in field CA1 of hippocampus. Here we determined the contribution of calpain-1 in another type of synaptic plasticity, the long-term depression (LTD) elicited by activation of type-I metabotropic glutamate receptors (mGluR-LTD). mGluR-LTD was associated with calpain-1 activation following T-type calcium channel opening, and resulted in the truncation of a regulatory subunit of PP2A, B56α. This signaling pathway was required for both the early and late phase of Arc translation during mGluR-LTD, through a mechanism involving mTOR and ribosomal protein S6 activation. In contrast, in hippocampal slices from calpain-1 knock-out (KO) mice, application of the mGluR agonist, DHPG, did not result in B56α truncation, increased Arc synthesis and reduced levels of membrane GluA1-containing AMPA receptors. Consistently, mGluR-LTD was impaired in calpain-1 KO mice, and the impairment could be rescued by phosphatase inhibitors, which also restored Arc translation in response to DHPG. Furthermore, calpain-1 KO mice exhibited impairment in fear memory extinction to tone presentation. These results indicate that calpain-1 plays a critical role in mGluR-LTD and is involved in many forms of synaptic plasticity and learning and memory.
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Affiliation(s)
- Guoqi Zhu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- Key Laboratory of Xin’an Medicine, Ministry of Education, Anhui University of Chinese Medicine, Hefei 230038, China
| | - Victor Briz
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- VIB Center for the Biology of Disease, KU Leuven, 3000 Leuven, Belgium
| | - Jeff Seinfeld
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
| | - Yan Liu
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Xiaoning Bi
- College of Osteopathic Medicine of the Pacific Western University of Health Sciences Pomona, CA 91766, CA 91766, USA
| | - Michel Baudry
- Graduate College of Biomedical Sciences, Pomona, CA 91766, USA
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Schieweck R, Popper B, Kiebler MA. Co-Translational Folding: A Novel Modulator of Local Protein Expression in Mammalian Neurons? Trends Genet 2016; 32:788-800. [DOI: 10.1016/j.tig.2016.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2016] [Revised: 10/04/2016] [Accepted: 10/11/2016] [Indexed: 01/15/2023]
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