1
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Lee JY, Gala DS, Kiourlappou M, Olivares-Abril J, Joha J, Titlow JS, Teodoro RO, Davis I. Murine glial protrusion transcripts predict localized Drosophila glial mRNAs involved in plasticity. J Cell Biol 2024; 223:e202306152. [PMID: 39037431 PMCID: PMC11262410 DOI: 10.1083/jcb.202306152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 06/14/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
The polarization of cells often involves the transport of specific mRNAs and their localized translation in distal projections. Neurons and glia are both known to contain long cytoplasmic processes, while localized transcripts have only been studied extensively in neurons, not glia, especially in intact nervous systems. Here, we predict 1,740 localized Drosophila glial transcripts by extrapolating from our meta-analysis of seven existing studies characterizing the localized transcriptomes and translatomes of synaptically associated mammalian glia. We demonstrate that the localization of mRNAs in mammalian glial projections strongly predicts the localization of their high-confidence Drosophila homologs in larval motor neuron-associated glial projections and are highly statistically enriched for genes associated with neurological diseases. We further show that some of these localized glial transcripts are specifically required in glia for structural plasticity at the nearby neuromuscular junction synapses. We conclude that peripheral glial mRNA localization is a common and conserved phenomenon and propose that it is likely to be functionally important in disease.
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Affiliation(s)
- Jeffrey Y. Lee
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Dalia S. Gala
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | | | - Jana Joha
- Department of Biochemistry, University of Oxford, Oxford, UK
| | | | - Rita O. Teodoro
- iNOVA4Health, NOVA Medical School | Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Ilan Davis
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
- Department of Biochemistry, University of Oxford, Oxford, UK
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2
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Yotova AY, Li LL, O'Leary A, Tegeder I, Reif A, Courtney MJ, Slattery DA, Freudenberg F. Synaptic proteome perturbations after maternal immune activation: Identification of embryonic and adult hippocampal changes. Brain Behav Immun 2024:S0889-1591(24)00519-1. [PMID: 39089536 DOI: 10.1016/j.bbi.2024.07.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Revised: 07/10/2024] [Accepted: 07/28/2024] [Indexed: 08/04/2024] Open
Abstract
BACKGROUND Maternal immune activation (MIA) triggers neurobiological changes in offspring, potentially reshaping the molecular synaptic landscape, with the hippocampus being particularly vulnerable. However, critical details regarding developmental timing of these changes and whether they differ between males and females remain unclear. METHODS We induced MIA in C57BL/6J mice on gestational day nine using the viral mimetic poly(I:C) and performed mass spectrometry-based proteomic analyses on hippocampal synaptoneurosomes of embryonic (E18) and adult (20 ± 1 weeks) MIA offspring. RESULTS In the embryonic synaptoneurosomes, MIA led to lipid, polysaccharide, and glycoprotein metabolism pathway disruptions. In the adult synaptic proteome, we observed a dynamic shift toward transmembrane trafficking, intracellular signalling cascades, including cell death and growth, and cytoskeletal organisation. In adults, many associated pathways overlapped between males and females. However, we found distinct sex-specific enrichment of dopaminergic and glutamatergic pathways. We identified 50 proteins altered by MIA in both embryonic and adult samples (28 with the same directionality), mainly involved in presynaptic structure and synaptic vesicle function. We probed human phenome-wide association study data in the cognitive and psychiatric domains, and 49 of the 50 genes encoding these proteins were significantly associated with the investigated phenotypes. CONCLUSIONS Our data emphasise the dynamic effects of viral-like MIA on developing and mature hippocampi and provide novel targets for study following prenatal immune challenges. The 22 proteins that changed directionality from the embryonic to adult hippocampus, suggestive of compensatory over-adaptions, are particularly attractive for future investigations.
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Affiliation(s)
- Anna Y Yotova
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany; Goethe University Frankfurt, Faculty of Biological Sciences, Institute of Cell Biology and Neuroscience, Frankfurt, Germany
| | - Li-Li Li
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Turku Brain and Mind Center, University of Turku and Åbo Akademi University, 20014 Turku, Finland
| | - Aet O'Leary
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany; Department of Neuropsychopharmacology, Institute of Chemistry, University of Tartu, Tartu, Estonia
| | - Irmgard Tegeder
- Goethe University Frankfurt, Faculty of Medicine, Institute of Clinical Pharmacology, Frankfurt, Germany
| | - Andreas Reif
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany
| | - Michael J Courtney
- Turku Bioscience Centre, University of Turku and Åbo Akademi University, 20520 Turku, Finland; Turku Brain and Mind Center, University of Turku and Åbo Akademi University, 20014 Turku, Finland
| | - David A Slattery
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany
| | - Florian Freudenberg
- Goethe University Frankfurt, University Hospital, Department of Psychiatry, Psychosomatic Medicine and Psychotherapy, Frankfurt, Germany; Goethe University Frankfurt, Faculty of Biological Sciences, Institute of Cell Biology and Neuroscience, Frankfurt, Germany.
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3
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Holt LM, Nestler EJ. Astrocytic transcriptional and epigenetic mechanisms of drug addiction. J Neural Transm (Vienna) 2024; 131:409-424. [PMID: 37940687 PMCID: PMC11066772 DOI: 10.1007/s00702-023-02716-4] [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: 08/21/2023] [Accepted: 10/24/2023] [Indexed: 11/10/2023]
Abstract
Addiction is a leading cause of disease burden worldwide and remains a challenge in current neuroscience research. Drug-induced lasting changes in gene expression are mediated by transcriptional and epigenetic regulation in the brain and are thought to underlie behavioral adaptations. Emerging evidence implicates astrocytes in regulating drug-seeking behaviors and demonstrates robust transcriptional response to several substances of abuse. This review focuses on the astrocytic transcriptional and epigenetic mechanisms of drug action.
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Affiliation(s)
- Leanne M Holt
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Eric J Nestler
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
- Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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4
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de Reus AJEM, Basak O, Dykstra W, van Asperen JV, van Bodegraven EJ, Hol EM. GFAP-isoforms in the nervous system: Understanding the need for diversity. Curr Opin Cell Biol 2024; 87:102340. [PMID: 38401182 DOI: 10.1016/j.ceb.2024.102340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/30/2024] [Indexed: 02/26/2024]
Abstract
Glial fibrillary acidic protein (GFAP) is an intermediate filament (IF) protein expressed in specific types of glial cells in the nervous system. The expression of GFAP is highly regulated during brain development and in neurological diseases. The presence of distinct GFAP-isoforms in various cell types, developmental stages, and diseases indicates that GFAP (post-)transcriptional regulation has a role in glial cell physiology and pathology. GFAP-isoforms differ in sub-cellular localisation, IF-network assembly properties, and IF-dynamics which results in distinct molecular interactions and mechanical properties of the IF-network. Therefore, GFAP (post-)transcriptional regulation is likely a mechanism by which radial glia, astrocytes, and glioma cells can modulate cellular function.
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Affiliation(s)
- Alexandra J E M de Reus
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Onur Basak
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Werner Dykstra
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Jessy V van Asperen
- Institut NeuroMyoGène (INMG), Unité Physiopathologie et Génétique du Neurone et du Muscle, Unversité Claude Bernard Lyon 1 CNRS UMR 5261, INSERM U1315, Lyon, France
| | - Emma J van Bodegraven
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Elly M Hol
- Department of Translational Neuroscience, Brain Center, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
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5
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Toyoda S, Handa T, Yong H, Takahashi H, Shiwaku H. IMPDH2 forms spots at branching sites and distal ends of astrocyte stem processes. Genes Cells 2024; 29:150-158. [PMID: 38009721 DOI: 10.1111/gtc.13088] [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: 10/10/2023] [Revised: 11/12/2023] [Accepted: 11/15/2023] [Indexed: 11/29/2023]
Abstract
Inosine monophosphate dehydrogenase (IMPDH) is a rate-limiting enzyme in the de novo GTP biosynthesis pathway. Recent studies suggest that IMPDH2, an isoform of IMPDH, can localize to specific subcellular compartments under certain conditions and regulate site-specific GTP availability and small GTPase activity in invasive cancer cells. However, it is unclear whether IMPDH2 plays a site-specific regulatory role in subcellular functions in healthy cells. In this study, we focused on brain cells and examined the localization pattern of IMPDH2. We discovered that IMPDH2 forms localized spots in the astrocytes of the adult mouse hippocampus. Further analysis of spot distribution in primary astrocyte cultures revealed that IMPDH2 spots are predominantly localized on branching sites and distal ends of astrocyte stem processes. Our findings suggest a potential unidentified role for IMPDH2 and GTP synthesis specifically at specialized nodes of astrocyte branches.
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Affiliation(s)
- Saori Toyoda
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Takehisa Handa
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Huang Yong
- Department of Neuropathology, Medical Research Institute and Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo, Japan
| | - Hidehiko Takahashi
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
| | - Hiroki Shiwaku
- Department of Psychiatry and Behavioral Sciences, Tokyo Medical and Dental University Graduate School, Tokyo, Japan
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6
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Cagnetta R, Flanagan JG, Sonenberg N. Control of Selective mRNA Translation in Neuronal Subcellular Compartments in Health and Disease. J Neurosci 2023; 43:7247-7263. [PMID: 37914402 PMCID: PMC10621772 DOI: 10.1523/jneurosci.2240-22.2023] [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: 12/06/2022] [Revised: 04/28/2023] [Accepted: 05/02/2023] [Indexed: 11/03/2023] Open
Abstract
In multiple cell types, mRNAs are transported to subcellular compartments, where local translation enables rapid, spatially localized, and specific responses to external stimuli. Mounting evidence has uncovered important roles played by local translation in vivo in axon survival, axon regeneration, and neural wiring, as well as strong links between dysregulation of local translation and neurologic disorders. Omic studies have revealed that >1000 mRNAs are present and can be selectively locally translated in the presynaptic and postsynaptic compartments from development to adulthood in vivo A large proportion of the locally translated mRNAs is specifically upregulated or downregulated in response to distinct extracellular signals. Given that the local translatome is large, selectively translated, and cue-specifically remodeled, a fundamental question concerns how selective translation is achieved locally. Here, we review the emerging regulatory mechanisms of local selective translation in neuronal subcellular compartments, their mRNA targets, and their orchestration. We discuss mechanisms of local selective translation that remain unexplored. Finally, we describe clinical implications and potential therapeutic strategies in light of the latest advances in gene therapy.
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Affiliation(s)
- Roberta Cagnetta
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
| | - John G Flanagan
- Department of Cell Biology and Program in Neuroscience, Harvard Medical School, Boston, Massachusetts 02115
| | - Nahum Sonenberg
- Department of Biochemistry and Goodman Cancer Institute, McGill University, Montreal, Quebec H3A 1A3, Canada
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7
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Martinez-Lozada Z, Todd FW, Schober AL, Krizman E, Robinson MB, Murai KK. Cooperative and competitive regulation of the astrocytic transcriptome by neurons and endothelial cells: Impact on astrocyte maturation. J Neurochem 2023; 167:52-75. [PMID: 37525469 PMCID: PMC10543513 DOI: 10.1111/jnc.15908] [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: 03/01/2023] [Revised: 06/19/2023] [Accepted: 06/20/2023] [Indexed: 08/02/2023]
Abstract
Astrocytes have essential roles in central nervous system (CNS) health and disease. During development, immature astrocytes show complex interactions with neurons, endothelial cells, and other glial cell types. Our work and that of others have shown that these interactions are important for astrocytic maturation. However, whether and how these cells work together to control this process remains poorly understood. Here, we test the hypothesis that cooperative interactions of astrocytes with neurons and endothelial cells promote astrocytic maturation. Astrocytes were cultured alone, with neurons, endothelial cells, or a combination of both. This was followed by astrocyte sorting, RNA sequencing, and bioinformatic analysis to detect transcriptional changes. Across culture configurations, 7302 genes were differentially expressed by 4 or more fold and organized into 8 groups that demonstrate cooperative and antagonist effects of neurons and endothelia on astrocytes. We also discovered that neurons and endothelial cells caused splicing of 200 and 781 mRNAs, respectively. Changes in gene expression were validated using quantitative PCR, western blot (WB), and immunofluorescence analysis. We found that the transcriptomic data from the three-culture configurations correlated with protein expression of three representative targets (FAM107A, GAT3, and GLT1) in vivo. Alternative splicing results also correlated with cortical tissue isoform representation of a target (Fibronectin 1) at different developmental stages. By comparing our results to published transcriptomes of immature and mature astrocytes, we found that neurons or endothelia shift the astrocytic transcriptome toward a mature state and that the presence of both cell types has a greater effect on maturation than either cell alone. These results increase our understanding of cellular interactions/pathways that contribute to astrocytic maturation. They also provide insight into how alterations to neurons and/or endothelial cells may alter astrocytes with implications for astrocytic changes in CNS disorders and diseases.
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Affiliation(s)
- Zila Martinez-Lozada
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Farmer W. Todd
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
| | - Alexandra L. Schober
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
| | - Elizabeth Krizman
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Michael B. Robinson
- Departments of Pediatrics and Systems Pharmacology & Translational Therapeutics, The Children’s Hospital of Philadelphia, University of Pennsylvania, Philadelphia, PA, USA, 19104-4318
| | - Keith K. Murai
- Centre for Research in Neuroscience, Department of Neurology & Neurosurgery, Brain Repair and Integrative Neuroscience Program, The Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada H3G 1A4
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8
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Ament SA, Poulopoulos A. The brain's dark transcriptome: Sequencing RNA in distal compartments of neurons and glia. Curr Opin Neurobiol 2023; 81:102725. [PMID: 37196598 PMCID: PMC10524153 DOI: 10.1016/j.conb.2023.102725] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 03/22/2023] [Accepted: 04/02/2023] [Indexed: 05/19/2023]
Abstract
Transcriptomic approaches are powerful strategies to map the molecular diversity of cells in the brain. Single-cell genomic atlases have now been compiled for entire mammalian brains. However, complementary techniques are only just beginning to map the subcellular transcriptomes from distal cellular compartments. We review single-cell datasets alongside subtranscriptome data from the mammalian brain to explore the development of cellular and subcellular diversity. We discuss how single-cell RNA-seq misses transcripts localized away from cell bodies, which form the 'dark transcriptome' of the brain: a collection of subtranscriptomes in dendrites, axons, growth cones, synapses, and endfeet with important roles in brain development and function. Recent advances in subcellular transcriptome sequencing are beginning to reveal these elusive pools of RNA. We outline the success stories to date in uncovering the constituent subtranscriptomes of neurons and glia, as well as present the emerging toolkit that is accelerating the pace of subtranscriptome discovery.
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Affiliation(s)
- Seth A Ament
- Department of Psychiatry, UM-MIND, and Institute for Genome Sciences, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Alexandros Poulopoulos
- Department of Pharmacology and UM-MIND, University of Maryland School of Medicine, Baltimore, MD, USA.
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9
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Stogsdill JA, Harwell CC, Goldman SA. Astrocytes as master modulators of neural networks: Synaptic functions and disease-associated dysfunction of astrocytes. Ann N Y Acad Sci 2023; 1525:41-60. [PMID: 37219367 DOI: 10.1111/nyas.15004] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Astrocytes are the most abundant glial cell type in the central nervous system and are essential to the development, plasticity, and maintenance of neural circuits. Astrocytes are heterogeneous, with their diversity rooted in developmental programs modulated by the local brain environment. Astrocytes play integral roles in regulating and coordinating neural activity extending far beyond their metabolic support of neurons and other brain cell phenotypes. Both gray and white matter astrocytes occupy critical functional niches capable of modulating brain physiology on time scales slower than synaptic activity but faster than those adaptive responses requiring a structural change or adaptive myelination. Given their many associations and functional roles, it is not surprising that astrocytic dysfunction has been causally implicated in a broad set of neurodegenerative and neuropsychiatric disorders. In this review, we focus on recent discoveries concerning the contributions of astrocytes to the function of neural networks, with a dual focus on the contribution of astrocytes to synaptic development and maturation, and on their role in supporting myelin integrity, and hence conduction and its regulation. We then address the emerging roles of astrocytic dysfunction in disease pathogenesis and on potential strategies for targeting these cells for therapeutic purposes.
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Affiliation(s)
| | - Corey C Harwell
- Department of Neurology, University of California San Francisco, San Francisco, California, USA
| | - Steven A Goldman
- Sana Biotechnology Inc., Cambridge, Massachusetts, USA
- Center for Translational Neuromedicine, University of Rochester, Rochester, New York, USA
- University of Copenhagen Faculty of Health and Medical Sciences, Copenhagen, Denmark
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10
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Welby E, Ebert AD. Diminished motor neuron activity driven by abnormal astrocytic EAAT1 glutamate transporter activity in spinal muscular atrophy is not fully restored after lentiviral SMN delivery. Glia 2023; 71:1311-1332. [PMID: 36655314 DOI: 10.1002/glia.24340] [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: 06/08/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 01/20/2023]
Abstract
Spinal muscular atrophy (SMA) is characterized by the loss of the lower spinal motor neurons due to survival motor neuron (SMN) deficiency. The motor neuron cell autonomous and non-cell autonomous disease mechanisms driving early glutamatergic dysfunction, a therapeutically targetable phenotype prior to motor neuron cell loss, remain unclear. Using microelectrode array analysis, we demonstrate that the secretome and cell surface proteins needed for proper synaptic modulation are likely disrupted in human SMA astrocytes and lead to diminished motor neuron activity. While healthy astrocyte conditioned media did not improve SMA motor neuron activity, SMA motor neurons robustly responded to healthy astrocyte neuromodulation in direct contact cultures. This suggests an important role of astrocyte synaptic-associated plasma membrane proteins and contact-mediated cellular interactions for proper motor neuron function in SMA. Specifically, we identified a significant reduction of the glutamate Na+ dependent excitatory amino acid transporter EAAT1 within human SMA astrocytes and SMA lumbar spinal cord tissue. The selective inhibition of EAAT1 in healthy co-cultures phenocopied the diminished neural activity observed in SMA astrocyte co-cultures. Caveolin-1, an SMN-interacting protein previously associated with local translation at the plasma membrane, was abnormally elevated in human SMA astrocytes. Although lentiviral SMN delivery to SMA astrocytes partially rescued EAAT1 expression, limited activity of healthy motor neurons was still observed in SMN-transduced SMA astrocyte co-cultures. Together, these data highlight the detrimental impact of astrocyte-mediated disease mechanisms on motor neuron function in SMA and that SMN delivery may be insufficient to fully restore astrocyte function at the synapse.
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Affiliation(s)
- Emily Welby
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Allison D Ebert
- Department of Cell Biology, Neurobiology and Anatomy, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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11
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Oudart M, Avila-Gutierrez K, Moch C, Dossi E, Milior G, Boulay AC, Gaudey M, Moulard J, Lombard B, Loew D, Bemelmans AP, Rouach N, Chapat C, Cohen-Salmon M. The ribosome-associated protein RACK1 represses Kir4.1 translation in astrocytes and influences neuronal activity. Cell Rep 2023; 42:112456. [PMID: 37126448 DOI: 10.1016/j.celrep.2023.112456] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 02/10/2023] [Accepted: 04/16/2023] [Indexed: 05/02/2023] Open
Abstract
The regulation of translation in astrocytes, the main glial cells in the brain, remains poorly characterized. We developed a high-throughput proteomics screen for polysome-associated proteins in astrocytes and focused on ribosomal protein receptor of activated protein C kinase 1 (RACK1), a critical factor in translational regulation. In astrocyte somata and perisynaptic astrocytic processes (PAPs), RACK1 preferentially binds to a number of mRNAs, including Kcnj10, encoding the inward-rectifying potassium (K+) channel Kir4.1. By developing an astrocyte-specific, conditional RACK1 knockout mouse model, we show that RACK1 represses production of Kir4.1 in hippocampal astrocytes and PAPs. Upregulation of Kir4.1 in the absence of RACK1 increases astrocytic Kir4.1-mediated K+ currents and volume. It also modifies neuronal activity attenuating burst frequency and duration. Reporter-based assays reveal that RACK1 controls Kcnj10 translation through the transcript's 5' untranslated region. Hence, translational regulation by RACK1 in astrocytes represses Kir4.1 expression and influences neuronal activity.
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Affiliation(s)
- Marc Oudart
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Katia Avila-Gutierrez
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clara Moch
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Elena Dossi
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Giampaolo Milior
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Anne-Cécile Boulay
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Mathis Gaudey
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Bérangère Lombard
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Damarys Loew
- CurieCoreTech Spectrométrie de Masse Protéomique, Institut Curie, University PSL, Paris, France
| | - Alexis-Pierre Bemelmans
- CEA, Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), CNRS, Université Paris-Sud, Université Paris-Saclay, Fontenay-aux-Roses, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France
| | - Clément Chapat
- Laboratoire de Biochimie, Ecole Polytechnique, CNRS, Université Paris-Saclay, Palaiseau, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology, College de France, CNRS, INSERM, Université PSL, Labex Memolife, Paris, France.
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12
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Cheung G, Chever O, Rollenhagen A, Quenech'du N, Ezan P, Lübke JHR, Rouach N. Astroglial Connexin 43 Regulates Synaptic Vesicle Release at Hippocampal Synapses. Cells 2023; 12:cells12081133. [PMID: 37190042 DOI: 10.3390/cells12081133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 04/01/2023] [Accepted: 04/03/2023] [Indexed: 05/17/2023] Open
Abstract
Connexin 43, an astroglial gap junction protein, is enriched in perisynaptic astroglial processes and plays major roles in synaptic transmission. We have previously found that astroglial Cx43 controls synaptic glutamate levels and allows for activity-dependent glutamine release to sustain physiological synaptic transmissions and cognitiogns. However, whether Cx43 is important for the release of synaptic vesicles, which is a critical component of synaptic efficacy, remains unanswered. Here, using transgenic mice with a glial conditional knockout of Cx43 (Cx43-/-), we investigate whether and how astrocytes regulate the release of synaptic vesicles from hippocampal synapses. We report that CA1 pyramidal neurons and their synapses develop normally in the absence of astroglial Cx43. However, a significant impairment in synaptic vesicle distribution and release dynamics were observed. In particular, the FM1-43 assays performed using two-photon live imaging and combined with multi-electrode array stimulation in acute hippocampal slices, revealed a slower rate of synaptic vesicle release in Cx43-/- mice. Furthermore, paired-pulse recordings showed that synaptic vesicle release probability was also reduced and is dependent on glutamine supply via Cx43 hemichannel (HC). Taken together, we have uncovered a role for Cx43 in regulating presynaptic functions by controlling the rate and probability of synaptic vesicle release. Our findings further highlight the significance of astroglial Cx43 in synaptic transmission and efficacy.
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Affiliation(s)
- Giselle Cheung
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Oana Chever
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Astrid Rollenhagen
- Institute for Neuroscience and Medicine INM-10, Research Center Jülich, 52428 Jülich, Germany
- Jülich-Aachen Research Alliance Translational Brain Medicine, 52056 Aachen, Germany
| | - Nicole Quenech'du
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Pascal Ezan
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
| | - Joachim H R Lübke
- Institute for Neuroscience and Medicine INM-10, Research Center Jülich, 52428 Jülich, Germany
- Jülich-Aachen Research Alliance Translational Brain Medicine, 52056 Aachen, Germany
- Department of Psychiatry, Psychotherapy and Psychosomatics, Rheinisch-Westfaelische Technische Hochschule Aachen University, 52056 Aachen, Germany
| | - Nathalie Rouach
- Neuroglial Interactions in Cerebral Physiology and Pathologies, Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, Université PSL, 75231 Paris, France
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13
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Luo J. Dysregulation of polarity proteins in astrocyte reactivity. Ageing Res Rev 2023; 86:101869. [PMID: 36736704 PMCID: PMC10026364 DOI: 10.1016/j.arr.2023.101869] [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: 10/13/2022] [Revised: 01/13/2023] [Accepted: 01/27/2023] [Indexed: 02/04/2023]
Abstract
Astrocytes are highly polarized neuroglial cells. Polarity is the basis for many of the diverse roles that astrocytes play in the normal and injured brain. Astrocytes are generally dormant and non-migratory under normal physiological conditions, where they perform a wide variety of intricate and essential tasks in preserving CNS homeostasis. In response to pathological insults, astrocytes shift from the normal dormant and homeostatic state to a reactive and migratory state through a process referred to as "reactive astrogliosis". Cell polarity proteins play a key role in the initiation and regulation of migration. Recent evidence suggests that cell polarity proteins are dysregulated during astrogliosis and may modulate astrocyte reactivity and alter the course of disease. Therefore, cell polarity proteins may provide novel therapeutic targets for modulating astrocyte reactivity in brain disorders.
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Affiliation(s)
- Jian Luo
- Palo Alto Veterans Institute for Research, VAPAHCS, Palo Alto, CA 94304, USA.
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14
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Prabhakar P, Pielot R, Landgraf P, Wissing J, Bayrhammer A, van Ham M, Gundelfinger ED, Jänsch L, Dieterich DC, Müller A. Monitoring regional astrocyte diversity by cell type-specific proteomic labeling in vivo. Glia 2023; 71:682-703. [PMID: 36401581 DOI: 10.1002/glia.24304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 10/29/2022] [Accepted: 11/03/2022] [Indexed: 11/21/2022]
Abstract
Astrocytes exhibit regional heterogeneity in morphology, function and molecular composition to support and modulate neuronal function and signaling in a region-specific manner. To characterize regional heterogeneity of astrocytic proteomes of different brain regions we established an inducible Aldh1l1-methionyl-tRNA-synthetaseL274G (MetRSL274G ) mouse line that allows astrocyte-specific metabolic labeling of newly synthesized proteins by azidonorleucine (ANL) in vivo and subsequent isolation of tagged proteins by click chemistry. We analyzed astrocytic proteins from four different brain regions by mass spectrometry. The induced expression of MetRSL274G is restricted to astrocytes and identified proteins show a high overlap with proteins compiled in "AstroProt," a newly established database for astrocytic proteins. Gene enrichment analysis reveals a high similarity among brain regions with subtle differences in enriched biological processes and in abundances of key astrocytic proteins for hippocampus, cortex and striatum. However, the cerebellar proteome stands out with proteins being highly associated with the calcium signaling pathway or with bipolar disorder. Subregional analysis of single astrocyte TAMRA intensities in hippocampal layers indicates distinct subregional heterogeneity of astrocytes and highlights the applicability of our toolbox to study differences of astrocytic proteomes in vivo.
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Affiliation(s)
- Priyadharshini Prabhakar
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Rainer Pielot
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Peter Landgraf
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany
| | - Josef Wissing
- Cellular Proteome Research Group, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Anne Bayrhammer
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Marco van Ham
- Cellular Proteome Research Group, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Eckart D Gundelfinger
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany.,Leibniz Institute for Neurobiology, RG Neuroplasticity, Magdeburg, Germany
| | - Lothar Jänsch
- Cellular Proteome Research Group, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Daniela C Dieterich
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Anke Müller
- Institute for Pharmacology and Toxicology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany.,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
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15
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Gala DS, Titlow JS, Teodoro RO, Davis I. Far from home: the role of glial mRNA localization in synaptic plasticity. RNA (NEW YORK, N.Y.) 2023; 29:153-169. [PMID: 36442969 PMCID: PMC9891262 DOI: 10.1261/rna.079422.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Neurons and glia are highly polarized cells, whose distal cytoplasmic functional subdomains require specific proteins. Neurons have axonal and dendritic cytoplasmic extensions containing synapses whose plasticity is regulated efficiently by mRNA transport and localized translation. The principles behind these mechanisms are equally attractive for explaining rapid local regulation of distal glial cytoplasmic projections, independent of their cell nucleus. However, in contrast to neurons, mRNA localization has received little experimental attention in glia. Nevertheless, there are many functionally diverse glial subtypes containing extensive networks of long cytoplasmic projections with likely localized regulation that influence neurons and their synapses. Moreover, glia have many other neuron-like properties, including electrical activity, secretion of gliotransmitters and calcium signaling, influencing, for example, synaptic transmission, plasticity and axon pruning. Here, we review previous studies concerning glial transcripts with important roles in influencing synaptic plasticity, focusing on a few cases involving localized translation. We discuss a variety of important questions about mRNA transport and localized translation in glia that remain to be addressed, using cutting-edge tools already available for neurons.
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Affiliation(s)
- Dalia S Gala
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Joshua S Titlow
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
| | - Rita O Teodoro
- iNOVA4Health, NOVA Medical School-Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa 1169-056, Portugal
| | - Ilan Davis
- Department of Biochemistry, The University of Oxford, Oxford OX1 3QU, United Kingdom
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16
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Tortuyaux R, Avila-Gutierrez K, Oudart M, Mazaré N, Mailly P, Deschemin JC, Vaulont S, Escartin C, Cohen-Salmon M. Physiopathological changes of ferritin mRNA density and distribution in hippocampal astrocytes in the mouse brain. J Neurochem 2022; 164:847-857. [PMID: 36562685 DOI: 10.1111/jnc.15747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 11/30/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022]
Abstract
Astrocytes are thought to play a crucial role in brain iron homeostasis. How they accomplish this regulation in vivo is unclear. In a recent transcriptomic analysis, we showed that polysomal Ftl1 and Fth1 mRNAs, encoding the ferritin light (Ftl) and heavy (Fth) chains that assemble into ferritin, a critical complex for iron storage and reduction, are enriched in perisynaptic astrocytic processes as compared to astrocytic soma. These data suggested that ferritin translation plays a specific role at the perisynaptic astrocytic interface and is tighly regulated by local translation. Here, we used our recently described AstroDot 3D in situ methodology to study the density and localization of ferritin mRNAs in astrocytes in the hippocampus in three different contexts in which local or systemic iron overload has been documented: aging, the hepcidin knock-out mouse model of hemochromatosis and the APP/PS1dE9 mouse model of Alzheimer's disease (AD). Our results showed that in wild type mice, Fth1 mRNA density was higher than Ftl1 and that both mRNAs were mostly distributed in astrocyte fine processes. Aging and absence of hepcidin caused an increased Fth1/Ftl1 ratio in astrocytes and in the case of aging, led to a redistribution of Fth1 mRNAs in astrocytic fine processes. In contrast, in AD mice, we observed a lower Fth1/Ftl1 ratio. Fth1 mRNAs became more somatic and Ftl1 mRNAs redistributed in large processes of astrocytes proximal to Amyloid beta (Aß) deposits. Hence, we propose that regulation of ferritin mRNA density and distribution in astrocytes contribute to iron homeostasis in physiology and pathophysiology.
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Affiliation(s)
- Romain Tortuyaux
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France.,Intensive Care Unit, CHU Lille, Lille, France
| | - Katia Avila-Gutierrez
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Marc Oudart
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Noémie Mazaré
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | - Philippe Mailly
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
| | | | - Sophie Vaulont
- CNRS, INSERM, Institut Cochin, Université Paris Cité, Paris, France
| | - Carole Escartin
- Université Paris-Saclay, CEA, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology (CIRB), Collège de France, CNRS, INSERM, Université PSL, Paris, France
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17
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Vasile F, Dossi E, Moulard J, Ezan P, Lecoin L, Cohen-Salmon M, Mailly P, Le Bert M, Couillin I, Bemelmans A, Rouach N. Pannexin 1 activity in astroglia sets hippocampal neuronal network patterns. PLoS Biol 2022; 20:e3001891. [PMID: 36477165 PMCID: PMC9728857 DOI: 10.1371/journal.pbio.3001891] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 10/24/2022] [Indexed: 12/12/2022] Open
Abstract
Astroglial release of molecules is thought to actively modulate neuronal activity, but the nature, release pathway, and cellular targets of these neuroactive molecules are still unclear. Pannexin 1, expressed by neurons and astrocytes, form nonselective large pore channels that mediate extracellular exchange of molecules. The functional relevance of these channels has been mostly studied in brain tissues, without considering their specific role in different cell types, or in neurons. Thus, our knowledge of astroglial pannexin 1 regulation and its control of neuronal activity remains very limited, largely due to the lack of tools targeting these channels in a cell-specific way. We here show that astroglial pannexin 1 expression in mice is developmentally regulated and that its activation is activity-dependent. Using astrocyte-specific molecular tools, we found that astroglial-specific pannexin 1 channel activation, in contrast to pannexin 1 activation in all cell types, selectively and negatively regulates hippocampal networks, with their disruption inducing a drastic switch from bursts to paroxysmal activity. This decrease in neuronal excitability occurs via an unconventional astroglial mechanism whereby pannexin 1 channel activity drives purinergic signaling-mediated regulation of hyperpolarisation-activated cyclic nucleotide (HCN)-gated channels. Our findings suggest that astroglial pannexin 1 channel activation serves as a negative feedback mechanism crucial for the inhibition of hippocampal neuronal networks.
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Affiliation(s)
- Flora Vasile
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Elena Dossi
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Julien Moulard
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Pascal Ezan
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Laure Lecoin
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Martine Cohen-Salmon
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Philippe Mailly
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
| | - Marc Le Bert
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, Orleans, France
| | - Isabelle Couillin
- CNRS UMR7355, Experimental and Molecular Immunology and Neurogenetics, Orleans, France
| | - Alexis Bemelmans
- Université Paris-Saclay, Commissariat à l’Energie Atomique et aux Energies Alternatives, CNRS, MIRCen, Laboratoire des Maladies Neurodégénératives, Fontenay-aux-Roses, France
| | - Nathalie Rouach
- Center for Interdisciplinary Research in Biology, Collège de France, CNRS, INSERM, Labex Memolife, PSL Research University, Paris, France
- * E-mail:
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18
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Badia-Soteras A, Heistek TS, Kater MSJ, Mak A, Negrean A, van den Oever MC, Mansvelder HD, Khakh BS, Min R, Smit AB, Verheijen MHG. Retraction of Astrocyte Leaflets From the Synapse Enhances Fear Memory. Biol Psychiatry 2022:S0006-3223(22)01705-X. [PMID: 36702661 DOI: 10.1016/j.biopsych.2022.10.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 10/07/2022] [Accepted: 10/20/2022] [Indexed: 01/28/2023]
Abstract
BACKGROUND The formation and retrieval of fear memories depends on orchestrated synaptic activity of neuronal ensembles within the hippocampus, and it is becoming increasingly evident that astrocytes residing in the environment of these synapses play a central role in shaping cellular memory representations. Astrocyte distal processes, known as leaflets, fine-tune synaptic activity by clearing neurotransmitters and limiting glutamate diffusion. However, how astroglial synaptic coverage contributes to mnemonic processing of fearful experiences remains largely unknown. METHODS We used electron microscopy to observe changes in astroglial coverage of hippocampal synapses during consolidation of fear memory in mice. To manipulate astroglial synaptic coverage, we depleted ezrin, an integral leaflet-structural protein, from hippocampal astrocytes using CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 gene editing. Next, a combination of Föster resonance energy transfer analysis, genetically encoded glutamate sensors, and whole-cell patch-clamp recordings was used to determine whether the proximity of astrocyte leaflets to the synapse is critical for synaptic integrity and function. RESULTS We found that consolidation of a recent fear memory is accompanied by a transient retraction of astrocyte leaflets from hippocampal synapses and increased activation of NMDA receptors. Accordingly, astrocyte-specific depletion of ezrin resulted in shorter astrocyte leaflets and reduced astrocyte contact with the synaptic cleft, which consequently boosted extrasynaptic glutamate diffusion and NMDA receptor activation. Importantly, after fear conditioning, these cellular phenotypes translated to increased retrieval-evoked activation of CA1 pyramidal neurons and enhanced fear memory expression. CONCLUSIONS Together, our data show that withdrawal of astrocyte leaflets from the synaptic cleft is an experience-induced, temporally regulated process that gates the strength of fear memories.
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Affiliation(s)
- Aina Badia-Soteras
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Tim S Heistek
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Mandy S J Kater
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Aline Mak
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Adrian Negrean
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Michel C van den Oever
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Huibert D Mansvelder
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Baljit S Khakh
- Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Rogier Min
- Department of Integrative Neurophysiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands; Department of Child Neurology, Emma Children's Hospital, Amsterdam University Medical Centers, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - August B Smit
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Mark H G Verheijen
- Department of Molecular and Cellular Neuroscience, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands.
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19
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Activity-dependent translation dynamically alters the proteome of the perisynaptic astrocyte process. Cell Rep 2022; 41:111474. [PMID: 36261025 PMCID: PMC9624251 DOI: 10.1016/j.celrep.2022.111474] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 06/16/2022] [Accepted: 09/19/2022] [Indexed: 01/07/2023] Open
Abstract
Within eukaryotic cells, translation is regulated independent of transcription, enabling nuanced, localized, and rapid responses to stimuli. Neurons respond transcriptionally and translationally to synaptic activity. Although transcriptional responses are documented in astrocytes, here we test whether astrocytes have programmed translational responses. We show that seizure activity rapidly changes the transcripts on astrocyte ribosomes, some predicted to be downstream of BDNF signaling. In acute slices, we quantify the extent to which cues of neuronal activity activate translation in astrocytes and show that this translational response requires the presence of neurons, indicating that the response is non-cell autonomous. We also show that this induction of new translation extends into the periphery of astrocytes. Finally, synaptic proteomics show that new translation is required for changes that occur in perisynaptic astrocyte protein composition after fear conditioning. Regulation of translation in astrocytes by neuronal activity suggests an additional mechanism by which astrocytes may dynamically modulate nervous system functioning.
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20
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Monday HR, Kharod SC, Yoon YJ, Singer RH, Castillo PE. Presynaptic FMRP and local protein synthesis support structural and functional plasticity of glutamatergic axon terminals. Neuron 2022; 110:2588-2606.e6. [PMID: 35728596 PMCID: PMC9391299 DOI: 10.1016/j.neuron.2022.05.024] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 03/31/2022] [Accepted: 05/26/2022] [Indexed: 10/18/2022]
Abstract
Learning and memory rely on long-lasting, synapse-specific modifications. Although postsynaptic forms of plasticity typically require local protein synthesis, whether and how local protein synthesis contributes to presynaptic changes remain unclear. Here, we examined the mouse hippocampal mossy fiber (MF)-CA3 synapse, which expresses both structural and functional presynaptic plasticity and contains presynaptic fragile X messenger ribonucleoprotein (FMRP), an RNA-binding protein involved in postsynaptic protein-synthesis-dependent plasticity. We report that MF boutons contain ribosomes and synthesize protein locally. The long-term potentiation of MF-CA3 synaptic transmission (MF-LTP) was associated with the translation-dependent enlargement of MF boutons. Remarkably, increasing in vitro or in vivo MF activity enhanced the protein synthesis in MFs. Moreover, the deletion of presynaptic FMRP blocked structural and functional MF-LTP, suggesting that FMRP is a critical regulator of presynaptic MF plasticity. Thus, presynaptic FMRP and protein synthesis dynamically control presynaptic structure and function in the mature mammalian brain.
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Affiliation(s)
- Hannah R Monday
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA.
| | - Shivani C Kharod
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Young J Yoon
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA; Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Robert H Singer
- Department of Cell Biology, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA
| | - Pablo E Castillo
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA; Department of Psychiatry and Behavioral Sciences, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, New York, NY 10461, USA.
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21
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Schober AL, Wicki-Stordeur LE, Murai KK, Swayne LA. Foundations and implications of astrocyte heterogeneity during brain development and disease. Trends Neurosci 2022; 45:692-703. [PMID: 35879116 DOI: 10.1016/j.tins.2022.06.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 05/25/2022] [Accepted: 06/29/2022] [Indexed: 11/25/2022]
Abstract
Astrocytes play crucial roles in regulating brain circuit formation and physiology. Recent technological advances have revealed unprecedented levels of astrocyte diversity encompassing molecular, morphological, and functional differences. This diversification is initiated during embryonic specification events and (in rodents) continues into the early postnatal period where it overlaps with peak synapse development and circuit refinement. In fact, several lines of evidence suggest astrocyte diversity both influences and is a consequence of molecular crosstalk among developing astrocytes and other cell types, notably neurons and their synapses. Neurological disease states exhibit additional layers of astrocyte heterogeneity, which could help shed light on these cells' key pathological roles. This review highlights recent advances in clarifying astrocyte heterogeneity and molecular/cellular crosstalk and identifies key outstanding questions.
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Affiliation(s)
- Alexandra L Schober
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada
| | | | - Keith K Murai
- Department of Neurology and Neurosurgery, Centre for Research in Neuroscience, Brain Repair and Integrative Neuroscience Program, Research Institute of the McGill University Health Centre, Montreal General Hospital, Montreal, QC, Canada; Quantitative Life Sciences Graduate Program, McGill University, Montreal, QC, Canada
| | - Leigh Anne Swayne
- Division of Medical Sciences, University of Victoria, Victoria, BC, Canada; Department of Cellular and Physiological Sciences, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada.
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22
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Men Y, Higashimori H, Reynolds K, Tu L, Jarvis R, Yang Y. Functionally Clustered mRNAs Are Distinctly Enriched at Cortical Astroglial Processes and Are Preferentially Affected by FMRP Deficiency. J Neurosci 2022; 42:5803-5814. [PMID: 35701158 PMCID: PMC9302465 DOI: 10.1523/jneurosci.0274-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/06/2022] [Accepted: 06/08/2022] [Indexed: 01/22/2023] Open
Abstract
Mature protoplasmic astroglia in the mammalian CNS uniquely possess a large number of fine processes that have been considered primary sites to mediate astroglia to neuron synaptic signaling. However, localized mechanisms for regulating interactions between astroglial processes and synapses, especially for regulating the expression of functional surface proteins at these fine processes, are largely unknown. Previously, we showed that the loss of the RNA binding protein FMRP in astroglia disrupts astroglial mGluR5 signaling and reduces expression of the major astroglial glutamate transporter GLT1 and glutamate uptake in the cortex of Fmr1 conditional deletion mice. In the current study, by examining ribosome localization using electron microscopy and identifying mRNAs enriched at cortical astroglial processes using synaptoneurosome/translating ribosome affinity purification and RNA-Seq in WT and FMRP-deficient male mice, our results reveal interesting localization-dependent functional clusters of mRNAs at astroglial processes. We further showed that the lack of FMRP preferentially alters the subcellular localization and expression of process-localized mRNAs. Together, we defined the role of FMRP in altering mRNA localization and expression at astroglial processes at the postnatal development (P30-P40) and provided new candidate mRNAs that are potentially regulated by FMRP in cortical astroglia.SIGNIFICANCE STATEMENT Localized mechanisms for regulating interactions between astroglial processes and synapses, especially for regulating the expression of functional surface proteins at these fine processes, are largely unknown. Previously, we showed that the loss of the RNA binding protein FMRP in astroglia disrupts expression of several astroglial surface proteins, such as mGluR5 and major astroglial glutamate transporter GLT1 in the cortex of FMRP-deficient mice. Our current study examined ribosome localization using electron microscopy and identified mRNAs enriched at cortical astroglial processes in WT and FMRP-deficient mice. These results reveal interesting localization-dependent functional clusters of mRNAs at astroglial processes and demonstrate that the lack of FMRP preferentially alters the subcellular localization and expression of process-localized mRNAs.
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Affiliation(s)
- Yuqin Men
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Haruki Higashimori
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Kathryn Reynolds
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Leona Tu
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Rachel Jarvis
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
| | - Yongjie Yang
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111
- Graduate School of Biomedical Sciences, Tufts University, Boston, Massachusetts 02111
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23
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Saint‐Martin M, Goda Y. Astrocyte–synapse interactions and cell adhesion molecules. FEBS J 2022. [DOI: 10.1111/febs.16540] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 05/20/2022] [Accepted: 05/31/2022] [Indexed: 12/22/2022]
Affiliation(s)
- Margaux Saint‐Martin
- Laboratory for Synaptic Plasticity and Connectivity RIKEN Center for Brain Science Wako‐shi, Saitama Japan
| | - Yukiko Goda
- Laboratory for Synaptic Plasticity and Connectivity RIKEN Center for Brain Science Wako‐shi, Saitama Japan
- Synapse Biology Unit Okinawa Institute of Science and Technology Graduate University Japan
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24
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A Proposed Role for Interactions between Argonautes, miRISC, and RNA Binding Proteins in the Regulation of Local Translation in Neurons and Glia. J Neurosci 2022; 42:3291-3301. [PMID: 35444007 PMCID: PMC9034781 DOI: 10.1523/jneurosci.2391-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 03/04/2022] [Accepted: 03/08/2022] [Indexed: 11/21/2022] Open
Abstract
The first evidence of local translation in the CNS appeared nearly 40 years ago, when electron microscopic studies showed polyribosomes localized to the base of dendritic spines. Since then, local translation has been established as an important regulatory mechanism for gene expression in polarized or functionally compartmentalized cells. While much attention has been placed on characterizing the local transcriptome and regulatory "grammar" directing mRNA localization in neurons and glia, less is understood about how these cells subsequently de-repress mRNA translation in their peripheral processes to produce a rapid translational response to stimuli. MicroRNA-mediated translation regulation offers a possible solution to this question. Not only do miRNAs provide the specificity needed for targeted gene regulation, but association and dynamic interactions between Argonaute (AGO) with sequence-specific RNA-binding proteins may provide a molecular switch to allow for de-repression of target mRNAs. Here, we review the expression and activity of different AGO proteins in miRNA-induced silencing complexes in neurons and glia and discuss known pathways of miRNA-mediated regulation, including activity-dependent pre-miRNA maturation in dendrites. We further detail work on AGO and RNA-binding protein interactions that allow for the reversal of miRNA-mediated translational silencing, and we propose a model for how intercellular communication may play a role in the regulation of local translation.
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25
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Xie Y, Kuan AT, Wang W, Herbert ZT, Mosto O, Olukoya O, Adam M, Vu S, Kim M, Tran D, Gómez N, Charpentier C, Sorour I, Lacey TE, Tolstorukov MY, Sabatini BL, Lee WCA, Harwell CC. Astrocyte-neuron crosstalk through Hedgehog signaling mediates cortical synapse development. Cell Rep 2022; 38:110416. [PMID: 35196485 PMCID: PMC8962654 DOI: 10.1016/j.celrep.2022.110416] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/04/2021] [Accepted: 01/28/2022] [Indexed: 12/12/2022] Open
Abstract
Neuron-glia interactions play a critical role in the regulation of synapse formation and circuit assembly. Here we demonstrate that canonical Sonic hedgehog (Shh) pathway signaling in cortical astrocytes acts to coordinate layer-specific synaptic connectivity. We show that the Shh receptor Ptch1 is expressed by cortical astrocytes during development and that Shh signaling is necessary and sufficient to promote the expression of genes involved in regulating synaptic development and layer-enriched astrocyte molecular identity. Loss of Shh in layer V neurons reduces astrocyte complexity and coverage by astrocytic processes in tripartite synapses; conversely, cell-autonomous activation of Shh signaling in astrocytes promotes cortical excitatory synapse formation. Furthermore, Shh-dependent genes Lrig1 and Sparc distinctively contribute to astrocyte morphology and synapse formation. Together, these results suggest that Shh secreted from deep-layer cortical neurons acts to specialize the molecular and functional features of astrocytes during development to shape circuit assembly and function. Xie et al. show that Sonic hedgehog expressed by cortical layer V neurons signals to Ptch1-expressing astrocytes where it is necessary to promote the expression of layer-enriched astrocyte gene networks that control synapse formation and astrocyte morphological complexity.
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Affiliation(s)
- Yajun Xie
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Aaron T Kuan
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Wengang Wang
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Zachary T Herbert
- Molecular Biology Core Facilities, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Olivia Mosto
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Olubusola Olukoya
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Manal Adam
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Steve Vu
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Minsu Kim
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Diana Tran
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Nicolás Gómez
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Claire Charpentier
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Ingie Sorour
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tiara E Lacey
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Michael Y Tolstorukov
- Department of Informatics and Analytics, Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | - Bernardo L Sabatini
- Howard Hughes Medical Institute, Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Wei-Chung Allen Lee
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Corey C Harwell
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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26
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Physiological synaptic activity and recognition memory require astroglial glutamine. Nat Commun 2022; 13:753. [PMID: 35136061 PMCID: PMC8826940 DOI: 10.1038/s41467-022-28331-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 01/07/2022] [Indexed: 12/23/2022] Open
Abstract
Presynaptic glutamate replenishment is fundamental to brain function. In high activity regimes, such as epileptic episodes, this process is thought to rely on the glutamate-glutamine cycle between neurons and astrocytes. However the presence of an astroglial glutamine supply, as well as its functional relevance in vivo in the healthy brain remain controversial, partly due to a lack of tools that can directly examine glutamine transfer. Here, we generated a fluorescent probe that tracks glutamine in live cells, which provides direct visual evidence of an activity-dependent glutamine supply from astroglial networks to presynaptic structures under physiological conditions. This mobilization is mediated by connexin43, an astroglial protein with both gap-junction and hemichannel functions, and is essential for synaptic transmission and object recognition memory. Our findings uncover an indispensable recruitment of astroglial glutamine in physiological synaptic activity and memory via an unconventional pathway, thus providing an astrocyte basis for cognitive processes. The authors present a fluorescent probe that tracks glutamine in live cells. They demonstrate the capabilities of the probe by providing direct visual evidence of an activity-dependent glutamine supply from astroglial networks to presynaptic structures under physiological conditions.
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27
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Estimating the glutamate transporter surface density in distinct sub-cellular compartments of mouse hippocampal astrocytes. PLoS Comput Biol 2022; 18:e1009845. [PMID: 35120128 PMCID: PMC8849624 DOI: 10.1371/journal.pcbi.1009845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 02/16/2022] [Accepted: 01/18/2022] [Indexed: 11/19/2022] Open
Abstract
Glutamate transporters preserve the spatial specificity of synaptic transmission by limiting glutamate diffusion away from the synaptic cleft, and prevent excitotoxicity by keeping the extracellular concentration of glutamate at low nanomolar levels. Glutamate transporters are abundantly expressed in astrocytes, and previous estimates have been obtained about their surface expression in astrocytes of the rat hippocampus and cerebellum. Analogous estimates for the mouse hippocampus are currently not available. In this work, we derive the surface density of astrocytic glutamate transporters in mice of different ages via quantitative dot blot. We find that the surface density of glial glutamate transporters is similar in 7-8 week old mice and rats. In mice, the levels of glutamate transporters increase until about 6 months of age and then begin to decline slowly. Our data, obtained from a combination of experimental and modeling approaches, point to the existence of stark differences in the density of expression of glutamate transporters across different sub-cellular compartments, indicating that the extent to which astrocytes limit extrasynaptic glutamate diffusion depends not only on their level of synaptic coverage, but also on the identity of the astrocyte compartment in contact with the synapse. Together, these findings provide information on how heterogeneity in the spatial distribution of glutamate transporters in the plasma membrane of hippocampal astrocytes my alter glutamate receptor activation out of the synaptic cleft.
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28
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Hobson BD, Kong L, Angelo MF, Lieberman OJ, Mosharov EV, Herzog E, Sulzer D, Sims PA. Subcellular and regional localization of mRNA translation in midbrain dopamine neurons. Cell Rep 2022; 38:110208. [PMID: 35021090 PMCID: PMC8844886 DOI: 10.1016/j.celrep.2021.110208] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/25/2021] [Accepted: 12/13/2021] [Indexed: 12/12/2022] Open
Abstract
Midbrain dopaminergic (mDA) neurons exhibit extensive dendritic and axonal arborizations, but local protein synthesis is not characterized in these neurons. Here, we investigate messenger RNA (mRNA) localization and translation in mDA neuronal axons and dendrites, both of which release dopamine (DA). Using highly sensitive ribosome-bound RNA sequencing and imaging approaches, we find no evidence for mRNA translation in mDA axons. In contrast, mDA neuronal dendrites in the substantia nigra pars reticulata (SNr) contain ribosomes and mRNAs encoding the major components of DA synthesis, release, and reuptake machinery. Surprisingly, we also observe dendritic localization of mRNAs encoding synaptic vesicle-related proteins, including those involved in exocytic fusion. Our results are consistent with a role for local translation in the regulation of DA release from dendrites, but not from axons. Our translatome data define a molecular signature of sparse mDA neurons in the SNr, including the enrichment of Atp2a3/SERCA3, an atypical ER calcium pump. Local translation regulates the subcellular proteome in neurons but has not been characterized in midbrain dopamine neurons, cells with large dendrites and axonal arborizations. Hobson et al. investigate messenger RNA localization and translation in midbrain dopamine neurons in the mouse brain, finding ribosomes and dopaminergic mRNAs in dendrites, but not axons.
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Affiliation(s)
- Benjamin D Hobson
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Linghao Kong
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA
| | - Maria Florencia Angelo
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France
| | - Ori J Lieberman
- Medical Scientist Training Program, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA
| | - Eugene V Mosharov
- Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA
| | - Etienne Herzog
- Interdisciplinary Institute for Neuroscience, Université de Bordeaux, Bordeaux, France; Interdisciplinary Institute for Neuroscience, CNRS UMR 5297, Bordeaux, France.
| | - David Sulzer
- Department of Neurology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Psychiatry, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Irving Medical Center, New York, NY 10032, USA; Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
| | - Peter A Sims
- Department of Systems Biology, Columbia University Irving Medical Center, New York 10032, NY, USA; Department of Biochemistry & Molecular Biophysics, Columbia University Irving Medical Center, New York, NY 10032, USA; Sulzberger Columbia Genome Center, Columbia University Irving Medical Center, New York, NY 10032, USA; Aligning Science Across Parkinson's (ASAP) Collaborative Research Network, Chevy Chase, MD, USA.
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29
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Aleksejenko N, Heller J. Super-resolution imaging to reveal the nanostructure of tripartite synapses. Neuronal Signal 2021; 5:NS20210003. [PMID: 34737894 PMCID: PMC8536832 DOI: 10.1042/ns20210003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2021] [Revised: 09/24/2021] [Accepted: 09/28/2021] [Indexed: 12/13/2022] Open
Abstract
Even though neurons are the main drivers of information processing in the brain and spinal cord, other cell types are important to mediate adequate flow of information. These include electrically passive glial cells such as microglia and astrocytes, which recently emerged as active partners facilitating proper signal transduction. In disease, these cells undergo pathophysiological changes that propel disease progression and change synaptic connections and signal transmission. In the healthy brain, astrocytic processes contact pre- and postsynaptic structures. These processes can be nanoscopic, and therefore only electron microscopy has been able to reveal their structure and morphology. However, electron microscopy is not suitable in revealing dynamic changes, and it is labour- and time-intensive. The dawn of super-resolution microscopy, techniques that 'break' the diffraction limit of conventional light microscopy, over the last decades has enabled researchers to reveal the nanoscopic synaptic environment. In this review, we highlight and discuss recent advances in our understanding of the nano-world of the so-called tripartite synapses, the relationship between pre- and postsynapse as well as astrocytic processes. Overall, novel super-resolution microscopy methods are needed to fully illuminate the intimate relationship between glia and neuronal cells that underlies signal transduction in the brain and that might be affected in diseases such as Alzheimer's disease and epilepsy.
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Affiliation(s)
- Natalija Aleksejenko
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
| | - Janosch P. Heller
- School of Biotechnology and National Institute for Cellular Biotechnology (NICB), Dublin City University, Glasnevin, Ireland
- Queen Square Institute of Neurology, University College London, London, United Kingdom
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30
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Fusco CM, Desch K, Dörrbaum AR, Wang M, Staab A, Chan ICW, Vail E, Villeri V, Langer JD, Schuman EM. Neuronal ribosomes exhibit dynamic and context-dependent exchange of ribosomal proteins. Nat Commun 2021; 12:6127. [PMID: 34675203 PMCID: PMC8531293 DOI: 10.1038/s41467-021-26365-x] [Citation(s) in RCA: 45] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 09/29/2021] [Indexed: 12/11/2022] Open
Abstract
Owing to their morphological complexity and dense network connections, neurons modify their proteomes locally, using mRNAs and ribosomes present in the neuropil (tissue enriched for dendrites and axons). Although ribosome biogenesis largely takes place in the nucleus and perinuclear region, neuronal ribosomal protein (RP) mRNAs have been frequently detected remotely, in dendrites and axons. Here, using imaging and ribosome profiling, we directly detected the RP mRNAs and their translation in the neuropil. Combining brief metabolic labeling with mass spectrometry, we found that a group of RPs rapidly associated with translating ribosomes in the cytoplasm and that this incorporation was independent of canonical ribosome biogenesis. Moreover, the incorporation probability of some RPs was regulated by location (neurites vs. cell bodies) and changes in the cellular environment (following oxidative stress). Our results suggest new mechanisms for the local activation, repair and/or specialization of the translational machinery within neuronal processes, potentially allowing neuronal synapses a rapid means to regulate local protein synthesis.
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Affiliation(s)
- Claudia M. Fusco
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Kristina Desch
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Aline R. Dörrbaum
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,Present Address: MOS, Center for Mass Spectrometry and Optical Spectroscopy, Mannheim, Germany
| | - Mantian Wang
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.508836.0Present Address: Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Anja Staab
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Ivy C. W. Chan
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.424247.30000 0004 0438 0426Present Address: German Center for Neurodegenerative Diseases, Bonn, Germany
| | - Eleanor Vail
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
| | - Veronica Villeri
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.412041.20000 0001 2106 639XPresent Address: Department of Neuroscience, University of Bordeaux, Bordeaux, France
| | - Julian D. Langer
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany ,grid.419494.50000 0001 1018 9466Max Planck Institute for Biophysics, Frankfurt, Germany
| | - Erin M. Schuman
- grid.419505.c0000 0004 0491 3878Max Planck Institute for Brain Research, Frankfurt, Germany
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31
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Chalkiadaki K, Statoulla E, Markou M, Bellou S, Bagli E, Fotsis T, Murphy C, Gkogkas CG. Translational control in neurovascular brain development. ROYAL SOCIETY OPEN SCIENCE 2021; 8:211088. [PMID: 34659781 PMCID: PMC8511748 DOI: 10.1098/rsos.211088] [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: 06/30/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
The human brain carries out complex tasks and higher functions and is crucial for organismal survival, as it senses both intrinsic and extrinsic environments. Proper brain development relies on the orchestrated development of different precursor cells, which will give rise to the plethora of mature brain cell-types. Within this process, neuronal cells develop closely to and in coordination with vascular cells (endothelial cells (ECs), pericytes) in a bilateral communication process that relies on neuronal activity, attractive or repulsive guidance cues for both cell types and on tight-regulation of gene expression. Translational control is a master regulator of the gene-expression pathway and in particular for neuronal and ECs, it can be localized in developmentally relevant (axon growth cone, endothelial tip cell) and mature compartments (synapses, axons). Herein, we will review mechanisms of translational control relevant to brain development in neurons and ECs in health and disease.
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Affiliation(s)
- Kleanthi Chalkiadaki
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Elpida Statoulla
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Maria Markou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Sofia Bellou
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Eleni Bagli
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Theodore Fotsis
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Carol Murphy
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
| | - Christos G. Gkogkas
- Division of Biomedical Research, Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, University Campus, 45110 Ioannina, Greece
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32
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Semyanov A, Verkhratsky A. Astrocytic processes: from tripartite synapses to the active milieu. Trends Neurosci 2021; 44:781-792. [PMID: 34479758 DOI: 10.1016/j.tins.2021.07.006] [Citation(s) in RCA: 110] [Impact Index Per Article: 36.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/09/2021] [Accepted: 07/20/2021] [Indexed: 12/16/2022]
Abstract
We define a new concept of 'active milieu' that unifies all components of nervous tissue (neuronal and glial compartments, extracellular space, extracellular matrix, and vasculature) into a dynamic information processing system. Within this framework, we focus on the role of astrocytic processes, classified into organelle-containing branches and organelle-free leaflets. We argue that astrocytic branches with emanating leaflets are homologous to dendritic shafts with spines. Within the active milieu, astrocytic processes are engaged in reciprocal interactions with neuronal compartments and communication with other cellular and non-cellular elements of the nervous tissue.
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Affiliation(s)
- Alexey Semyanov
- Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia; Faculty of Biology, Moscow State University, Moscow, Russia; Sechenov First Moscow State Medical University, Moscow, Russia.
| | - Alexei Verkhratsky
- Sechenov First Moscow State Medical University, Moscow, Russia; Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Achucarro Center for Neuroscience, IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain; Department of Neurosciences, University of the Basque Country UPV/EHU and CIBERNED, Leioa, Spain.
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33
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Perez JD, Fusco CM, Schuman EM. A Functional Dissection of the mRNA and Locally Synthesized Protein Population in Neuronal Dendrites and Axons. Annu Rev Genet 2021; 55:183-207. [PMID: 34460296 DOI: 10.1146/annurev-genet-030321-054851] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Neurons are characterized by a complex morphology that enables the generation of subcellular compartments with unique biochemical and biophysical properties, such as dendrites, axons, and synapses. To sustain these different compartments and carry a wide array of elaborate operations, neurons express a diverse repertoire of gene products. Extensive regulation at both the messenger RNA (mRNA) and protein levels allows for the differentiation of subcellular compartments as well as numerous forms of plasticity in response to variable stimuli. Among the multiple mechanisms that control cellular functions, mRNA translation is manipulated by neurons to regulate where and when a protein emerges. Interestingly, transcriptomic and translatomic profiles of both dendrites and axons have revealed that the mRNA population only partially predicts the local protein population and that this relation significantly varies between different gene groups. Here, we describe the space that local translation occupies within the large molecular and regulatory complexity of neurons, in contrast to other modes of regulation. We then discuss the specialized organization of mRNAs within different neuronal compartments, as revealed by profiles of the local transcriptome. Finally, we discuss the features and functional implications of both locally correlated-and anticorrelated-mRNA-protein relations both under baseline conditions and during synaptic plasticity. Expected final online publication date for the Annual Review of Genetics, Volume 55 is November 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Julio D Perez
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Claudia M Fusco
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt, Germany;
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34
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Han X, Burger LL, Garcia-Galiano D, Moenter SM, Myers MG, Olson DP, Elias CF. Protocol to extract actively translated mRNAs from mouse hypothalamus by translating ribosome affinity purification. STAR Protoc 2021; 2:100589. [PMID: 34159322 PMCID: PMC8196219 DOI: 10.1016/j.xpro.2021.100589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Here, we present an in-depth protocol for extracting ribosome-bound mRNAs in low-abundance cells of hypothalamic nuclei. mRNAs are extracted from the micropunched tissue using refined translating ribosome affinity purification. Isolated RNAs can be used for sequencing or transcript quantification. This protocol enables the identification of actively translated mRNAs in varying physiological states and can be modified for use in any neuronal subpopulation labeled with a ribo-tag. We use leptin receptor-expressing neurons as an example to illustrate the protocol. For complete details on the use and execution of this protocol, please refer to Han et al. (2020).
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Affiliation(s)
- Xingfa Han
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Isotope Research Lab, Sichuan Agricultural University, Ya’an 625014, China
| | - Laura L. Burger
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - David Garcia-Galiano
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Suzanne M. Moenter
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Martin G. Myers
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI 48109, USA
| | - David P. Olson
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Internal Medicine, Division of Metabolism, Endocrinology and Diabetes, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48109, USA
| | - Carol F. Elias
- Department of Molecular & integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, USA
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35
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O'Leary LA, Mechawar N. Implication of cerebral astrocytes in major depression: A review of fine neuroanatomical evidence in humans. Glia 2021; 69:2077-2099. [PMID: 33734498 DOI: 10.1002/glia.23994] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 01/01/2023]
Abstract
Postmortem investigations have implicated astrocytes in many neurological and psychiatric conditions. Multiple brain regions from individuals with major depressive disorder (MDD) have lower expression levels of astrocyte markers and lower densities of astrocytes labeled for these markers, suggesting a loss of astrocytes in this mental illness. This paper reviews the general properties of human astrocytes, the methods to study them, and the postmortem evidence for astrocyte pathology in MDD. When comparing astrocyte density and morphometry studies, astrocytes are more abundant and smaller in human subcortical than cortical brain regions, and immunohistochemical labeling for the astrocyte markers glial fibrillary acidic protein (GFAP) and vimentin (VIM) reveals fewer than 15% of all astrocytes that are present in cortical and subcortical regions, as revealed using other staining techniques. By combining astrocyte densities and morphometry, a model was made to illustrate that domain organization is mostly limited to GFAP-IR astrocytes. Using these markers and others, alterations of astrocyte densities appear more widespread than those for astrocyte morphologies throughout the brain of individuals having died with MDD. This review suggests how reduced astrocyte densities may relate to the association of depressive episodes in MDD with elevated S100 beta (S100B) cerebrospinal fluid serum levels. Finally, a potassium imbalance theory is proposed that integrates the reduced astrocyte densities generated from postmortem studies with a hypothesis for the antidepressant effects of ketamine generated from rodent studies.
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Affiliation(s)
- Liam Anuj O'Leary
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, Quebec, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada
| | - Naguib Mechawar
- McGill Group for Suicide Studies, Douglas Mental Health University Institute, Verdun, Quebec, Canada.,Integrated Program in Neuroscience, McGill University, Montreal, Quebec, Canada.,Department of Psychiatry, McGill University, Montreal, Quebec, Canada
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36
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RNA Localization and Local Translation in Glia in Neurological and Neurodegenerative Diseases: Lessons from Neurons. Cells 2021; 10:cells10030632. [PMID: 33809142 PMCID: PMC8000831 DOI: 10.3390/cells10030632] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Revised: 03/03/2021] [Accepted: 03/09/2021] [Indexed: 12/11/2022] Open
Abstract
Cell polarity is crucial for almost every cell in our body to establish distinct structural and functional domains. Polarized cells have an asymmetrical morphology and therefore their proteins need to be asymmetrically distributed to support their function. Subcellular protein distribution is typically achieved by localization peptides within the protein sequence. However, protein delivery to distinct cellular compartments can rely, not only on the transport of the protein itself but also on the transport of the mRNA that is then translated at target sites. This phenomenon is known as local protein synthesis. Local protein synthesis relies on the transport of mRNAs to subcellular domains and their translation to proteins at target sites by the also localized translation machinery. Neurons and glia specially depend upon the accurate subcellular distribution of their proteome to fulfil their polarized functions. In this sense, local protein synthesis has revealed itself as a crucial mechanism that regulates proper protein homeostasis in subcellular compartments. Thus, deregulation of mRNA transport and/or of localized translation can lead to neurological and neurodegenerative diseases. Local translation has been more extensively studied in neurons than in glia. In this review article, we will summarize the state-of-the art research on local protein synthesis in neuronal function and dysfunction, and we will discuss the possibility that local translation in glia and deregulation thereof contributes to neurological and neurodegenerative diseases.
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Passlick S, Rose CR, Petzold GC, Henneberger C. Disruption of Glutamate Transport and Homeostasis by Acute Metabolic Stress. Front Cell Neurosci 2021; 15:637784. [PMID: 33603647 PMCID: PMC7884476 DOI: 10.3389/fncel.2021.637784] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 01/11/2021] [Indexed: 01/02/2023] Open
Abstract
High-affinity, Na+-dependent glutamate transporters are the primary means by which synaptically released glutamate is removed from the extracellular space. They restrict the spread of glutamate from the synaptic cleft into the perisynaptic space and reduce its spillover to neighboring synapses. Thereby, glutamate uptake increases the spatial precision of synaptic communication. Its dysfunction and the entailing rise of the extracellular glutamate concentration accompanied by an increased spread of glutamate result in a loss of precision and in enhanced excitation, which can eventually lead to neuronal death via excitotoxicity. Efficient glutamate uptake depends on a negative resting membrane potential as well as on the transmembrane gradients of the co-transported ions (Na+, K+, and H+) and thus on the proper functioning of the Na+/K+-ATPase. Consequently, numerous studies have documented the impact of an energy shortage, as occurring for instance during an ischemic stroke, on glutamate clearance and homeostasis. The observations range from rapid changes in the transport activity to altered expression of glutamate transporters. Notably, while astrocytes account for the majority of glutamate uptake under physiological conditions, they may also become a source of extracellular glutamate elevation during metabolic stress. However, the mechanisms of the latter phenomenon are still under debate. Here, we review the recent literature addressing changes of glutamate uptake and homeostasis triggered by acute metabolic stress, i.e., on a timescale of seconds to minutes.
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Affiliation(s)
- Stefan Passlick
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Christine R Rose
- Institute of Neurobiology, Faculty of Mathematics and Natural Sciences, Heinrich Heine University Duesseldorf, Duesseldorf, Germany
| | - Gabor C Petzold
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Division of Vascular Neurology, University Hospital Bonn, Bonn, Germany
| | - Christian Henneberger
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany.,German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.,Institute of Neurology, University College London, London, United Kingdom
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Mazaré N, Oudart M, Cohen-Salmon M. Local translation in perisynaptic and perivascular astrocytic processes - a means to ensure astrocyte molecular and functional polarity? J Cell Sci 2021; 134:237323. [PMID: 33483366 DOI: 10.1242/jcs.251629] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Together with the compartmentalization of mRNAs in distal regions of the cytoplasm, local translation constitutes a prominent and evolutionarily conserved mechanism mediating cellular polarization and the regulation of protein delivery in space and time. The translational regulation of gene expression enables a rapid response to stimuli or to a change in the environment, since the use of pre-existing mRNAs can bypass time-consuming nuclear control mechanisms. In the brain, the translation of distally localized mRNAs has been mainly studied in neurons, whose cytoplasmic protrusions may be more than 1000 times longer than the diameter of the cell body. Importantly, alterations in local translation in neurons have been implicated in several neurological diseases. Astrocytes, the most abundant glial cells in the brain, are voluminous, highly ramified cells that project long processes to neurons and brain vessels, and dynamically regulate distal synaptic and vascular functions. Recent research has demonstrated the presence of local translation at these astrocytic interfaces that might regulate the functional compartmentalization of astrocytes. In this Review, we summarize our current knowledge about the localization and local translation of mRNAs in the distal perisynaptic and perivascular processes of astrocytes, and discuss their possible contribution to the molecular and functional polarity of astrocytes.
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Affiliation(s)
- Noémie Mazaré
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France.,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
| | - Marc Oudart
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France.,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
| | - Martine Cohen-Salmon
- Physiology and Physiopathology of the Gliovascular Unit Research Group, Center for Interdisciplinary Research in Biology (CIRB), College de France, CNRS Unité Mixte de Recherche 724, INSERM Unité 1050, Labex Memolife, PSL Research University, F-75005 Paris, France .,École doctorale Cerveau Cognition Comportement 'ED3C' No. 158, Pierre and Marie Curie University, F-75005 Paris, France
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Minehart JA, Speer CM. A Picture Worth a Thousand Molecules-Integrative Technologies for Mapping Subcellular Molecular Organization and Plasticity in Developing Circuits. Front Synaptic Neurosci 2021; 12:615059. [PMID: 33469427 PMCID: PMC7813761 DOI: 10.3389/fnsyn.2020.615059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/07/2020] [Indexed: 12/23/2022] Open
Abstract
A key challenge in developmental neuroscience is identifying the local regulatory mechanisms that control neurite and synaptic refinement over large brain volumes. Innovative molecular techniques and high-resolution imaging tools are beginning to reshape our view of how local protein translation in subcellular compartments drives axonal, dendritic, and synaptic development and plasticity. Here we review recent progress in three areas of neurite and synaptic study in situ-compartment-specific transcriptomics/translatomics, targeted proteomics, and super-resolution imaging analysis of synaptic organization and development. We discuss synergies between sequencing and imaging techniques for the discovery and validation of local molecular signaling mechanisms regulating synaptic development, plasticity, and maintenance in circuits.
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Affiliation(s)
| | - Colenso M. Speer
- Department of Biology, University of Maryland, College Park, MD, United States
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40
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Immunoprecipitation of Ribosome-Bound mRNAs from Astrocytic Perisynaptic Processes of the Mouse Hippocampus. STAR Protoc 2020; 1:100198. [PMID: 33377092 PMCID: PMC7757553 DOI: 10.1016/j.xpro.2020.100198] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Translation of distally localized mRNAs is an evolutionary mechanism occurring in polarized cells. It has been observed in astrocytes, whose processes contact blood vessels and synapses. Here, we describe a protocol for the purification of the entire pool of ribosome-bound mRNAs in perisynaptic astrocytic processes (PAPs). Our procedure combines the preparation of synaptogliosomes with a refined translating ribosome affinity purification technique. This approach can be used in any brain region to probe the physiological relevance of local translation in PAPs. For complete details on the use and execution of this protocol, please refer to Mazaré et al. (2020).
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Manninen T, Saudargiene A, Linne ML. Astrocyte-mediated spike-timing-dependent long-term depression modulates synaptic properties in the developing cortex. PLoS Comput Biol 2020; 16:e1008360. [PMID: 33170856 PMCID: PMC7654831 DOI: 10.1371/journal.pcbi.1008360] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 09/22/2020] [Indexed: 12/26/2022] Open
Abstract
Astrocytes have been shown to modulate synaptic transmission and plasticity in specific cortical synapses, but our understanding of the underlying molecular and cellular mechanisms remains limited. Here we present a new biophysicochemical model of a somatosensory cortical layer 4 to layer 2/3 synapse to study the role of astrocytes in spike-timing-dependent long-term depression (t-LTD) in vivo. By applying the synapse model and electrophysiological data recorded from rodent somatosensory cortex, we show that a signal from a postsynaptic neuron, orchestrated by endocannabinoids, astrocytic calcium signaling, and presynaptic N-methyl-D-aspartate receptors coupled with calcineurin signaling, induces t-LTD which is sensitive to the temporal difference between post- and presynaptic firing. We predict for the first time the dynamics of astrocyte-mediated molecular mechanisms underlying t-LTD and link complex biochemical networks at presynaptic, postsynaptic, and astrocytic sites to the time window of t-LTD induction. During t-LTD a single astrocyte acts as a delay factor for fast neuronal activity and integrates fast neuronal sensory processing with slow non-neuronal processing to modulate synaptic properties in the brain. Our results suggest that astrocytes play a critical role in synaptic computation during postnatal development and are of paramount importance in guiding the development of brain circuit functions, learning and memory.
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Affiliation(s)
- Tiina Manninen
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
- Department of Neurobiology, Stanford University, Stanford, CA, USA
| | - Ausra Saudargiene
- Neuroscience Institute, Lithuanian University of Health Sciences, Kaunas, Lithuania
- Department of Informatics, Vytautas Magnus University, Kaunas, Lithuania
| | - Marja-Leena Linne
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
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Poitevin F, Kushner A, Li X, Dao Duc K. Structural Heterogeneities of the Ribosome: New Frontiers and Opportunities for Cryo-EM. Molecules 2020; 25:E4262. [PMID: 32957592 PMCID: PMC7570653 DOI: 10.3390/molecules25184262] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 09/11/2020] [Accepted: 09/15/2020] [Indexed: 12/18/2022] Open
Abstract
The extent of ribosomal heterogeneity has caught increasing interest over the past few years, as recent studies have highlighted the presence of structural variations of the ribosome. More precisely, the heterogeneity of the ribosome covers multiple scales, including the dynamical aspects of ribosomal motion at the single particle level, specialization at the cellular and subcellular scale, or evolutionary differences across species. Upon solving the ribosome atomic structure at medium to high resolution, cryogenic electron microscopy (cryo-EM) has enabled investigating all these forms of heterogeneity. In this review, we present some recent advances in quantifying ribosome heterogeneity, with a focus on the conformational and evolutionary variations of the ribosome and their functional implications. These efforts highlight the need for new computational methods and comparative tools, to comprehensively model the continuous conformational transition pathways of the ribosome, as well as its evolution. While developing these methods presents some important challenges, it also provides an opportunity to extend our interpretation and usage of cryo-EM data, which would more generally benefit the study of molecular dynamics and evolution of proteins and other complexes.
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Affiliation(s)
- Frédéric Poitevin
- Department of LCLS Data Analytics, Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA;
| | - Artem Kushner
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Xinpei Li
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
| | - Khanh Dao Duc
- Department of Mathematics, University of British Columbia, Vancouver, BC V6T 1Z4, Canada; (A.K.); (X.L.)
- Department of Computer Science, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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