1
|
Wen W, Turrigiano GG. Keeping Your Brain in Balance: Homeostatic Regulation of Network Function. Annu Rev Neurosci 2024; 47:41-61. [PMID: 38382543 DOI: 10.1146/annurev-neuro-092523-110001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
To perform computations with the efficiency necessary for animal survival, neocortical microcircuits must be capable of reconfiguring in response to experience, while carefully regulating excitatory and inhibitory connectivity to maintain stable function. This dynamic fine-tuning is accomplished through a rich array of cellular homeostatic plasticity mechanisms that stabilize important cellular and network features such as firing rates, information flow, and sensory tuning properties. Further, these functional network properties can be stabilized by different forms of homeostatic plasticity, including mechanisms that target excitatory or inhibitory synapses, or that regulate intrinsic neuronal excitability. Here we discuss which aspects of neocortical circuit function are under homeostatic control, how this homeostasis is realized on the cellular and molecular levels, and the pathological consequences when circuit homeostasis is impaired. A remaining challenge is to elucidate how these diverse homeostatic mechanisms cooperate within complex circuits to enable them to be both flexible and stable.
Collapse
Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
| | - Gina G Turrigiano
- Department of Biology, Brandeis University, Waltham, Massachusetts, USA;
| |
Collapse
|
2
|
Wen W, Turrigiano GG. Modular Arrangement of Synaptic and Intrinsic Homeostatic Plasticity within Visual Cortical Circuits. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.01.596982. [PMID: 38853882 PMCID: PMC11160741 DOI: 10.1101/2024.06.01.596982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
Neocortical circuits use synaptic and intrinsic forms of homeostatic plasticity to stabilize key features of network activity, but whether these different homeostatic mechanisms act redundantly, or can be independently recruited to stabilize different network features, is unknown. Here we used pharmacological and genetic perturbations both in vitro and in vivo to determine whether synaptic scaling and intrinsic homeostatic plasticity (IHP) are arranged and recruited in a hierarchical or modular manner within L2/3 pyramidal neurons in rodent V1. Surprisingly, although the expression of synaptic scaling and IHP was dependent on overlapping trafficking pathways, they could be independently recruited by manipulating spiking activity or NMDAR signaling, respectively. Further, we found that changes in visual experience that affect NMDAR activation but not mean firing selectively trigger IHP, without recruiting synaptic scaling. These findings support a modular model in which synaptic and intrinsic homeostatic plasticity respond to and stabilize distinct aspects of network activity.
Collapse
Affiliation(s)
- Wei Wen
- Department of Biology, Brandeis University, Waltham, MA 02453, USA
| | | |
Collapse
|
3
|
Mitias S, Schaffer N, Nair S, Hook C, Lindberg I. ProSAAS is Preferentially Secreted from Neurons During Homeostatic Scaling and Reduces Amyloid Plaque Size in the 5xFAD Mouse Hippocampus. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.18.590133. [PMID: 38712265 PMCID: PMC11071301 DOI: 10.1101/2024.04.18.590133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The accumulation of β-amyloid in Alzheimer's disease greatly impacts neuronal health and synaptic function. To maintain network stability in the face of altered synaptic activity, neurons engage a feedback mechanism termed homeostatic scaling; however, this process is thought to be disrupted during disease progression. Previous proteomics studies have shown that one of the most highly regulated proteins in cell culture models of homeostatic scaling is the small secretory chaperone proSAAS. Our prior work has shown that proSAAS exhibits anti-aggregant behavior against alpha synuclein and β-amyloid fibrillation in vitro, and is upregulated in cell models of proteostatic stress. However, the specific role that this protein might play in homeostatic scaling, and its anti-aggregant role in Alzheimer's progression, is not clear. To learn more about the role of proSAAS in maintaining hippocampal proteostasis, we compared its expression in a primary neuron model of homeostatic scaling to other synaptic components using Western blotting and qPCR, revealing that proSAAS protein responses to homeostatic up- and down-regulation were significantly higher than those of two other synaptic vesicle components, 7B2 and carboxypeptidase E. However, proSAAS mRNA expression was static, suggesting translational control (and/or reduced degradation). ProSAAS was readily released upon depolarization of differentiated hippocampal cultures, supporting its synaptic localization. Immunohistochemical analysis demonstrated abundant proSAAS within the mossy fiber layer of the hippocampus in both wild-type and 5xFAD mice; in the latter, proSAAS was also concentrated around amyloid plaques. Interestingly, overexpression of proSAAS in the CA1 region via stereotaxic injection of proSAAS-encoding AAV2/1 significantly decreased amyloid plaque burden in 5xFAD mice. We hypothesize that dynamic changes in proSAAS expression play a critical role in hippocampal proteostatic processes, both in the context of normal homeostatic plasticity and in the control of protein aggregation during Alzheimer's disease progression.
Collapse
Affiliation(s)
- Samira Mitias
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Nicholas Schaffer
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Saaya Nair
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Chelsea Hook
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| | - Iris Lindberg
- Dept. of Neurobiology, Univ. of Maryland School of Medicine, Baltimore, MD
| |
Collapse
|
4
|
Davis BA, Chen HY, Ye Z, Ostlund I, Tippani M, Das D, Sripathy SR, Wang Y, Martin JM, Shim G, Panchwagh NM, Moses RL, Farinelli F, Bohlen JF, Li M, Luikart BW, Jaffe AE, Maher BJ. TCF4 Mutations Disrupt Synaptic Function Through Dysregulation of RIMBP2 in Patient-Derived Cortical Neurons. Biol Psychiatry 2024; 95:662-675. [PMID: 37573005 PMCID: PMC10858293 DOI: 10.1016/j.biopsych.2023.07.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/21/2023] [Accepted: 07/14/2023] [Indexed: 08/14/2023]
Abstract
BACKGROUND Genetic variation in the TCF4 (transcription factor 4) gene is associated with risk for a variety of developmental and psychiatric conditions, which includes a syndromic form of autism spectrum disorder called Pitt-Hopkins syndrome (PTHS). TCF4 encodes an activity-dependent transcription factor that is highly expressed during cortical development and in animal models has been shown to regulate various aspects of neuronal development and function. However, our understanding of how disease-causing mutations in TCF4 confer pathophysiology in a human context is lacking. METHODS To model PTHS, we differentiated human cortical neurons from human induced pluripotent stem cells that were derived from patients with PTHS and neurotypical individuals. To identify pathophysiology and disease mechanisms, we assayed cortical neurons with whole-cell electrophysiology, Ca2+ imaging, multielectrode arrays, immunocytochemistry, and RNA sequencing. RESULTS Cortical neurons derived from patients with TCF4 mutations showed deficits in spontaneous synaptic transmission, network excitability, and homeostatic plasticity. Transcriptomic analysis indicated that these phenotypes resulted in part from altered expression of genes involved in presynaptic neurotransmission and identified the presynaptic binding protein RIMBP2 as the most differentially expressed gene in PTHS neurons. Remarkably, TCF4-dependent deficits in spontaneous synaptic transmission and network excitability were rescued by increasing RIMBP2 expression in presynaptic neurons. CONCLUSIONS Taken together, these results identify TCF4 as a critical transcriptional regulator of human synaptic development and plasticity and specifically identifies dysregulation of presynaptic function as an early pathophysiology in PTHS.
Collapse
Affiliation(s)
- Brittany A Davis
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Huei-Ying Chen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Zengyou Ye
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Isaac Ostlund
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Madhavi Tippani
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Debamitra Das
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Srinidhi Rao Sripathy
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Yanhong Wang
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Jacqueline M Martin
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Gina Shim
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Neel M Panchwagh
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Rebecca L Moses
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Federica Farinelli
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Joseph F Bohlen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland
| | - Meijie Li
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Bryan W Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire
| | - Andrew E Jaffe
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland; McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland; Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland; Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Brady J Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, Maryland; Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland; Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland.
| |
Collapse
|
5
|
Saha O, Melo de Farias AR, Pelletier A, Siedlecki-Wullich D, Landeira BS, Gadaut J, Carrier A, Vreulx AC, Guyot K, Shen Y, Bonnefond A, Amouyel P, Tcw J, Kilinc D, Queiroz CM, Delahaye F, Lambert JC, Costa MR. The Alzheimer's disease risk gene BIN1 regulates activity-dependent gene expression in human-induced glutamatergic neurons. Mol Psychiatry 2024:10.1038/s41380-024-02502-y. [PMID: 38514804 DOI: 10.1038/s41380-024-02502-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 02/22/2024] [Accepted: 02/27/2024] [Indexed: 03/23/2024]
Abstract
Bridging Integrator 1 (BIN1) is the second most important Alzheimer's disease (AD) risk gene, but its physiological roles in neurons and its contribution to brain pathology remain largely elusive. In this work, we show that BIN1 plays a critical role in the regulation of calcium homeostasis, electrical activity, and gene expression of glutamatergic neurons. Using single-cell RNA-sequencing on cerebral organoids generated from isogenic BIN1 wild type (WT), heterozygous (HET) and homozygous knockout (KO) human-induced pluripotent stem cells (hiPSCs), we show that BIN1 is mainly expressed by oligodendrocytes and glutamatergic neurons, like in the human brain. Both BIN1 HET and KO cerebral organoids show specific transcriptional alterations, mainly associated with ion transport and synapses in glutamatergic neurons. We then demonstrate that BIN1 cell-autonomously regulates gene expression in glutamatergic neurons by using a novel protocol to generate pure culture of hiPSC-derived induced neurons (hiNs). Using this system, we also show that BIN1 plays a key role in the regulation of neuronal calcium transients and electrical activity via its interaction with the L-type voltage-gated calcium channel Cav1.2. BIN1 KO hiNs show reduced activity-dependent internalization and higher Cav1.2 expression compared to WT hiNs. Pharmacological blocking of this channel with clinically relevant doses of nifedipine, a calcium channel blocker, partly rescues electrical and gene expression alterations in BIN1 KO glutamatergic neurons. Further, we show that transcriptional alterations in BIN1 KO hiNs that affect biological processes related to calcium homeostasis are also present in glutamatergic neurons of the human brain at late stages of AD pathology. Together, these findings suggest that BIN1-dependent alterations in neuronal properties could contribute to AD pathophysiology and that treatment with low doses of clinically approved calcium blockers should be considered as an option to slow disease-onset and progression.
Collapse
Affiliation(s)
- Orthis Saha
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Ana Raquel Melo de Farias
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
- Brain Institute, Federal University of Rio Grande do Norte, Av. Senador Salgado Filho, 3000, Campus Universitário, Lagoa, Nova, 59078-970, Natal, Brazil
| | - Alexandre Pelletier
- Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, 59045, Lille, Cedex, France
- Department of Pharmacology, Physiology & Biophysics, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Dolores Siedlecki-Wullich
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Bruna Soares Landeira
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Johanna Gadaut
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Arnaud Carrier
- Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, 59045, Lille, Cedex, France
| | - Anaïs-Camille Vreulx
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Karine Guyot
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Yun Shen
- Department of Pharmacology, Physiology & Biophysics, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Amelie Bonnefond
- Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, 59045, Lille, Cedex, France
| | - Philippe Amouyel
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Julia Tcw
- Department of Pharmacology, Physiology & Biophysics, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
- Bioinformatics Program, Faculty of Computing & Data Sciences, Boston University, Boston, MA, 02115, USA
| | - Devrim Kilinc
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Claudio Marcos Queiroz
- Brain Institute, Federal University of Rio Grande do Norte, Av. Senador Salgado Filho, 3000, Campus Universitário, Lagoa, Nova, 59078-970, Natal, Brazil
| | - Fabien Delahaye
- Univ. Lille, Inserm, CNRS, CHU Lille, Institut Pasteur de Lille, U1283-UMR 8199 EGID, Pôle Recherche, 1 Place de Verdun, 59045, Lille, Cedex, France
| | - Jean-Charles Lambert
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France
| | - Marcos R Costa
- Univ. Lille, Inserm, CHU Lille, Institut Pasteur de Lille, U1167-RID-AGE facteurs de risque et déterminants moléculaires des maladies liées au vieillissement, DISTALZ, 1 rue du Professeur Calmette, 59019, Lille, France.
- Brain Institute, Federal University of Rio Grande do Norte, Av. Senador Salgado Filho, 3000, Campus Universitário, Lagoa, Nova, 59078-970, Natal, Brazil.
| |
Collapse
|
6
|
Magnati S, Alladio E, Bracco E. A Survey on the Expression of the Ubiquitin Proteasome System Components HECT- and RBR-E3 Ubiquitin Ligases and E2 Ubiquitin-Conjugating and E1 Ubiquitin-Activating Enzymes during Human Brain Development. Int J Mol Sci 2024; 25:2361. [PMID: 38397039 PMCID: PMC10889685 DOI: 10.3390/ijms25042361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/14/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024] Open
Abstract
Human brain development involves a tightly regulated sequence of events that starts shortly after conception and continues up to adolescence. Before birth, neurogenesis occurs, implying an extensive differentiation process, sustained by changes in the gene expression profile alongside proteome remodeling, regulated by the ubiquitin proteasome system (UPS) and autophagy. The latter processes rely on the selective tagging with ubiquitin of the proteins that must be disposed of. E3 ubiquitin ligases accomplish the selective recognition of the target proteins. At the late stage of neurogenesis, the brain starts to take shape, and neurons migrate to their designated locations. After birth, neuronal myelination occurs, and, in parallel, neurons form connections among each other throughout the synaptogenesis process. Due to the malfunctioning of UPS components, aberrant brain development at the very early stages leads to neurodevelopmental disorders. Through deep data mining and analysis and by taking advantage of machine learning-based models, we mapped the transcriptomic profile of the genes encoding HECT- and ring-between-ring (RBR)-E3 ubiquitin ligases as well as E2 ubiquitin-conjugating and E1 ubiquitin-activating enzymes during human brain development, from early post-conception to adulthood. The inquiry outcomes unveiled some implications for neurodevelopment-related disorders.
Collapse
Affiliation(s)
- Stefano Magnati
- Centro Regionale Anti Doping—A. Bertinaria, Orbassano, 10043 Turin, Italy;
- Politecnico di Torino, 10129, Turin, Italy
| | - Eugenio Alladio
- Centro Regionale Anti Doping—A. Bertinaria, Orbassano, 10043 Turin, Italy;
- Department of Chemistry, University of Turin, 10125 Turin, Italy
| | - Enrico Bracco
- Department of Oncology, University of Turin, 10043 Orbassano, Italy
- Istituto Nazionale Ricerca Metrologica, 10135 Turin, Italy
| |
Collapse
|
7
|
Beck M, Covino R, Hänelt I, Müller-McNicoll M. Understanding the cell: Future views of structural biology. Cell 2024; 187:545-562. [PMID: 38306981 DOI: 10.1016/j.cell.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/05/2023] [Accepted: 12/11/2023] [Indexed: 02/04/2024]
Abstract
Determining the structure and mechanisms of all individual functional modules of cells at high molecular detail has often been seen as equal to understanding how cells work. Recent technical advances have led to a flush of high-resolution structures of various macromolecular machines, but despite this wealth of detailed information, our understanding of cellular function remains incomplete. Here, we discuss present-day limitations of structural biology and highlight novel technologies that may enable us to analyze molecular functions directly inside cells. We predict that the progression toward structural cell biology will involve a shift toward conceptualizing a 4D virtual reality of cells using digital twins. These will capture cellular segments in a highly enriched molecular detail, include dynamic changes, and facilitate simulations of molecular processes, leading to novel and experimentally testable predictions. Transferring biological questions into algorithms that learn from the existing wealth of data and explore novel solutions may ultimately unveil how cells work.
Collapse
Affiliation(s)
- Martin Beck
- Max Planck Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt am Main, Germany; Goethe University Frankfurt, Frankfurt, Germany.
| | - Roberto Covino
- Frankfurt Institute for Advanced Studies, Ruth-Moufang-Straße 1, 60438 Frankfurt am Main, Germany.
| | - Inga Hänelt
- Goethe University Frankfurt, Frankfurt, Germany.
| | | |
Collapse
|
8
|
Radulescu CI, Doostdar N, Zabouri N, Melgosa-Ecenarro L, Wang X, Sadeh S, Pavlidi P, Airey J, Kopanitsa M, Clopath C, Barnes SJ. Age-related dysregulation of homeostatic control in neuronal microcircuits. Nat Neurosci 2023; 26:2158-2170. [PMID: 37919424 PMCID: PMC10689243 DOI: 10.1038/s41593-023-01451-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/06/2023] [Indexed: 11/04/2023]
Abstract
Neuronal homeostasis prevents hyperactivity and hypoactivity. Age-related hyperactivity suggests homeostasis may be dysregulated in later life. However, plasticity mechanisms preventing age-related hyperactivity and their efficacy in later life are unclear. We identify the adult cortical plasticity response to elevated activity driven by sensory overstimulation, then test how plasticity changes with age. We use in vivo two-photon imaging of calcium-mediated cellular/synaptic activity, electrophysiology and c-Fos-activity tagging to show control of neuronal activity is dysregulated in the visual cortex in late adulthood. Specifically, in young adult cortex, mGluR5-dependent population-wide excitatory synaptic weakening and inhibitory synaptogenesis reduce cortical activity following overstimulation. In later life, these mechanisms are downregulated, so that overstimulation results in synaptic strengthening and elevated activity. We also find overstimulation disrupts cognition in older but not younger animals. We propose that specific plasticity mechanisms fail in later life dysregulating neuronal microcircuit homeostasis and that the age-related response to overstimulation can impact cognitive performance.
Collapse
Affiliation(s)
- Carola I Radulescu
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Nazanin Doostdar
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Nawal Zabouri
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Leire Melgosa-Ecenarro
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Xingjian Wang
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Sadra Sadeh
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
- Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | - Pavlina Pavlidi
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
- Department of Pharmacology, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Joe Airey
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | | - Claudia Clopath
- Department of Biomedical Engineering, Imperial College London, South Kensington Campus, London, UK
| | - Samuel J Barnes
- UK Dementia Research Institute, Department of Brain Sciences, Imperial College London, Hammersmith Hospital Campus, London, UK.
| |
Collapse
|
9
|
Hasan S, Fernandopulle MS, Humble SW, Frankenfield AM, Li H, Prestil R, Johnson KR, Ryan BJ, Wade-Martins R, Ward ME, Hao L. Multi-modal proteomic characterization of lysosomal function and proteostasis in progranulin-deficient neurons. Mol Neurodegener 2023; 18:87. [PMID: 37974165 PMCID: PMC10655356 DOI: 10.1186/s13024-023-00673-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 10/25/2023] [Indexed: 11/19/2023] Open
Abstract
BACKGROUND Progranulin (PGRN) is a lysosomal glycoprotein implicated in various neurodegenerative diseases, including frontotemporal dementia and neuronal ceroid lipofuscinosis. Over 70 mutations discovered in the GRN gene all result in reduced expression of the PGRN protein. Genetic and functional studies point toward a regulatory role for PGRN in lysosome functions. However, the detailed molecular function of PGRN within lysosomes and the impact of PGRN deficiency on lysosomes remain unclear. METHODS We developed multifaceted proteomic techniques to characterize the dynamic lysosomal biology in living human neurons and fixed mouse brain tissues. Using lysosome proximity labeling and immuno-purification of intact lysosomes, we characterized lysosome compositions and interactome in both human induced pluripotent stem cell (iPSC)-derived glutamatergic neurons (i3Neurons) and mouse brains. Using dynamic stable isotope labeling by amino acids in cell culture (dSILAC) proteomics, we measured global protein half-lives in human i3Neurons for the first time. RESULTS Leveraging the multi-modal proteomics and live-cell imaging techniques, we comprehensively characterized how PGRN deficiency changes the molecular and functional landscape of neuronal lysosomes. We found that PGRN loss impairs the lysosome's degradative capacity with increased levels of v-ATPase subunits on the lysosome membrane, increased hydrolases within the lysosome, altered protein regulations related to lysosomal transport, and elevated lysosomal pH. Consistent with impairments in lysosomal function, GRN-null i3Neurons and frontotemporal dementia patient-derived i3Neurons carrying GRN mutation showed pronounced alterations in protein turnover, such as cathepsins and proteins related to supramolecular polymerization and inherited neurodegenerative diseases. CONCLUSION This study suggested PGRN as a critical regulator of lysosomal pH and degradative capacity, which influences global proteostasis in neurons. Beyond the study of progranulin deficiency, these newly developed proteomic methods in neurons and brain tissues provided useful tools and data resources for the field to study the highly dynamic neuronal lysosome biology.
Collapse
Affiliation(s)
- Saadia Hasan
- National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Department of Neurodegenerative Disease, UK Dementia Research Institute, Institute of Neurology, University College London, London, UK
- Augusta University, University of Georgia Medical Partnership, Athens, GA, USA
| | - Michael S Fernandopulle
- National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
- Medical Scientist Training Program, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stewart W Humble
- National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Department of Physiology, Anatomy and Genetics, Oxford Parkinson's Disease Centre, Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford, OX1 3QU, UK
| | | | - Haorong Li
- Department of Chemistry, George Washington University, Washington, DC, USA
| | - Ryan Prestil
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Kory R Johnson
- National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Brent J Ryan
- Department of Physiology, Anatomy and Genetics, Oxford Parkinson's Disease Centre, Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford, OX1 3QU, UK
| | - Richard Wade-Martins
- Department of Physiology, Anatomy and Genetics, Oxford Parkinson's Disease Centre, Kavli Institute for Nanoscience Discovery, University of Oxford, Dorothy Crowfoot Hodgkin Building, South Parks Road, Oxford, OX1 3QU, UK
| | - Michael E Ward
- National Institute of Neurological, Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA.
| | - Ling Hao
- Department of Chemistry, George Washington University, Washington, DC, USA.
| |
Collapse
|
10
|
Parkes M, Landers NL, Gramlich MW. Recently recycled synaptic vesicles use multi-cytoskeletal transport and differential presynaptic capture probability to establish a retrograde net flux during ISVE in central neurons. Front Cell Dev Biol 2023; 11:1286915. [PMID: 38020880 PMCID: PMC10657820 DOI: 10.3389/fcell.2023.1286915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 10/18/2023] [Indexed: 12/01/2023] Open
Abstract
Presynapses locally recycle synaptic vesicles to efficiently communicate information. During use and recycling, proteins on the surface of synaptic vesicles break down and become less efficient. In order to maintain efficient presynaptic function and accommodate protein breakdown, new proteins are regularly produced in the soma and trafficked to presynaptic locations where they replace older protein-carrying vesicles. Maintaining a balance of new proteins and older proteins is thus essential for presynaptic maintenance and plasticity. While protein production and turnover have been extensively studied, it is still unclear how older synaptic vesicles are trafficked back to the soma for recycling in order to maintain balance. In the present study, we use a combination of fluorescence microscopy, hippocampal cell cultures, and computational analyses to determine the mechanisms that mediate older synaptic vesicle trafficking back to the soma. We show that synaptic vesicles, which have recently undergone exocytosis, can differentially utilize either the microtubule or the actin cytoskeleton networks. We show that axonally trafficked vesicles traveling with higher speeds utilize the microtubule network and are less likely to be captured by presynapses, while slower vesicles utilize the actin network and are more likely to be captured by presynapses. We also show that retrograde-driven vesicles are less likely to be captured by a neighboring presynapse than anterograde-driven vesicles. We show that the loss of synaptic vesicle with bound molecular motor myosin V is the mechanism that differentiates whether vesicles will utilize the microtubule or actin networks. Finally, we present a theoretical framework of how our experimentally observed retrograde vesicle trafficking bias maintains the balance with previously observed rates of new vesicle trafficking from the soma.
Collapse
|
11
|
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.
Collapse
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
| |
Collapse
|
12
|
Tang Q, Chen X. Nascent Proteomics: Chemical Tools for Monitoring Newly Synthesized Proteins. Angew Chem Int Ed Engl 2023; 62:e202305866. [PMID: 37309018 DOI: 10.1002/anie.202305866] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/10/2023] [Accepted: 06/12/2023] [Indexed: 06/14/2023]
Abstract
Cellular proteins are dynamically regulated in response to environmental stimuli. Conventional proteomics compares the entire proteome in different cellular states to identify differentially expressed proteins, which suffers from limited sensitivity for analyzing acute and subtle changes. To address this challenge, nascent proteomics has been developed, which selectively analyzes the newly synthesized proteins, thus offering a more sensitive and timely insight into the dynamic changes of the proteome. In this Minireview, we discuss recent advancements in nascent proteomics, with an emphasis on methodological developments. Also, we delve into the current challenges and provide an outlook on the future prospects of this exciting field.
Collapse
Affiliation(s)
- Qi Tang
- College of Chemistry and Molecular Engineering, Beijing National Laboratory for Molecular Sciences, Peking University, Beijing, 100871, China
| | - Xing Chen
- College of Chemistry and Molecular Engineering, Peking-Tsinghua Center for Life Science, Beijing National Laboratory for Molecular Sciences, Synthetic and Functional Biomolecules Center, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Peking University, Beijing, 100871, China
| |
Collapse
|
13
|
Downs M, Zaia J, Sethi MK. Mass spectrometry methods for analysis of extracellular matrix components in neurological diseases. MASS SPECTROMETRY REVIEWS 2023; 42:1848-1875. [PMID: 35719114 PMCID: PMC9763553 DOI: 10.1002/mas.21792] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/12/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
The brain extracellular matrix (ECM) is a highly glycosylated environment and plays important roles in many processes including cell communication, growth factor binding, and scaffolding. The formation of structures such as perineuronal nets (PNNs) is critical in neuroprotection and neural plasticity, and the formation of molecular networks is dependent in part on glycans. The ECM is also implicated in the neuropathophysiology of disorders such as Alzheimer's disease (AD), Parkinson's disease (PD), and Schizophrenia (SZ). As such, it is of interest to understand both the proteomic and glycomic makeup of healthy and diseased brain ECM. Further, there is a growing need for site-specific glycoproteomic information. Over the past decade, sample preparation, mass spectrometry, and bioinformatic methods have been developed and refined to provide comprehensive information about the glycoproteome. Core ECM molecules including versican, hyaluronan and proteoglycan link proteins, and tenascin are dysregulated in AD, PD, and SZ. Glycomic changes such as differential sialylation, sulfation, and branching are also associated with neurodegeneration. A more thorough understanding of the ECM and its proteomic, glycomic, and glycoproteomic changes in brain diseases may provide pathways to new therapeutic options.
Collapse
Affiliation(s)
- Margaret Downs
- Department of Biochemistry, Center for Biomedical Mass Spectrometry, Boston University, Boston, Massachusetts, USA
| | - Joseph Zaia
- Department of Biochemistry, Center for Biomedical Mass Spectrometry, Boston University, Boston, Massachusetts, USA
- Bioinformatics Program, Boston University, Boston, Massachusetts, USA
| | - Manveen K Sethi
- Department of Biochemistry, Center for Biomedical Mass Spectrometry, Boston University, Boston, Massachusetts, USA
| |
Collapse
|
14
|
Nagasawa Y, Ueda HH, Kawabata H, Murakoshi H. LOV2-based photoactivatable CaMKII and its application to single synapses: Local Optogenetics. Biophys Physicobiol 2023; 20:e200027. [PMID: 38496236 PMCID: PMC10941968 DOI: 10.2142/biophysico.bppb-v20.0027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 06/02/2023] [Indexed: 03/19/2024] Open
Abstract
Optogenetic techniques offer a high spatiotemporal resolution to manipulate cellular activity. For instance, Channelrhodopsin-2 with global light illumination is the most widely used to control neuronal activity at the cellular level. However, the cellular scale is much larger than the diffraction limit of light (<1 μm) and does not fully exploit the features of the "high spatial resolution" of optogenetics. For instance, until recently, there were no optogenetic methods to induce synaptic plasticity at the level of single synapses. To address this, we developed an optogenetic tool named photoactivatable CaMKII (paCaMKII) by fusing a light-sensitive domain (LOV2) to CaMKIIα, which is a protein abundantly expressed in neurons of the cerebrum and hippocampus and essential for synaptic plasticity. Combining photoactivatable CaMKII with two-photon excitation, we successfully activated it in single spines, inducing synaptic plasticity (long-term potentiation) in hippocampal neurons. We refer to this method as "Local Optogenetics", which involves the local activation of molecules and measurement of cellular responses. In this review, we will discuss the characteristics of LOV2, the recent development of its derivatives, and the development and application of paCaMKII.
Collapse
Affiliation(s)
- Yutaro Nagasawa
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hiromi H Ueda
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Haruka Kawabata
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| | - Hideji Murakoshi
- Supportive Center for Brain Research, National Institute for Physiological Sciences, Okazaki, Aichi 444-8585, Japan
- Department of Physiological Sciences, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Aichi 444-8585, Japan
| |
Collapse
|
15
|
Sun C, Desch K, Nassim-Assir B, Giandomenico SL, Nemcova P, Langer JD, Schuman EM. An abundance of free regulatory (19 S) proteasome particles regulates neuronal synapses. Science 2023; 380:eadf2018. [PMID: 37228199 DOI: 10.1126/science.adf2018] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 04/04/2023] [Indexed: 05/27/2023]
Abstract
The proteasome, the major protein-degradation machine in cells, regulates neuronal synapses and long-term information storage. Here, using super-resolution microscopy, we found that the two essential subcomplexes of the proteasome, the regulatory (19S) and catalytic (20S) particles, are differentially distributed within individual rat cortical neurons. We discovered an unexpected abundance of free 19S particles near synapses. The free neuronal 19S particles bind and deubiquitylate lysine 63-ubiquitin (Lys63-ub), a non-proteasome-targeting ubiquitin linkage. Pull-down assays revealed a significant overrepresentation of synaptic molecules as Lys63-ub interactors. Inhibition of the 19S deubiquitylase activity significantly altered excitatory synaptic transmission and reduced the synaptic availability of AMPA receptors at multiple trafficking points in a proteasome-independent manner. Together, these results reveal a moonlighting function of the regulatory proteasomal subcomplex near synapses.
Collapse
Affiliation(s)
- Chao Sun
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Kristina Desch
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | | | | | - Paulina Nemcova
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
- Max Planck Institute for Biophysics, 60438 Frankfurt am Main, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| |
Collapse
|
16
|
Wang Y, Lin J, Li J, Yan L, Li W, He X, Ma H. Chronic Neuronal Inactivity Utilizes the mTOR-TFEB Pathway to Drive Transcription-Dependent Autophagy for Homeostatic Up-Scaling. J Neurosci 2023; 43:2631-2652. [PMID: 36868861 PMCID: PMC10089247 DOI: 10.1523/jneurosci.0146-23.2023] [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: 01/24/2023] [Revised: 02/16/2023] [Accepted: 02/26/2023] [Indexed: 03/05/2023] Open
Abstract
Activity-dependent changes in protein expression are critical for neuronal plasticity, a fundamental process for the processing and storage of information in the brain. Among the various forms of plasticity, homeostatic synaptic up-scaling is unique in that it is induced primarily by neuronal inactivity. However, precisely how the turnover of synaptic proteins occurs in this homeostatic process remains unclear. Here, we report that chronically inhibiting neuronal activity in primary cortical neurons prepared from embryonic day (E)18 Sprague Dawley rats (both sexes) induces autophagy, thereby regulating key synaptic proteins for up-scaling. Mechanistically, chronic neuronal inactivity causes dephosphorylation of ERK and mTOR, which induces transcription factor EB (TFEB)-mediated cytonuclear signaling and drives transcription-dependent autophagy to regulate αCaMKII and PSD95 during synaptic up-scaling. Together, these findings suggest that mTOR-dependent autophagy, which is often triggered by metabolic stressors such as starvation, is recruited and sustained during neuronal inactivity to maintain synaptic homeostasis, a process that ensures proper brain function and if impaired can cause neuropsychiatric disorders such as autism.SIGNIFICANCE STATEMENT In the mammalian brain, protein turnover is tightly controlled by neuronal activation to ensure key neuronal functions during long-lasting synaptic plasticity. However, a long-standing question is how this process occurs during synaptic up-scaling, a process that requires protein turnover but is induced by neuronal inactivation. Here, we report that mTOR-dependent signaling, which is often triggered by metabolic stressors such as starvation, is "hijacked" by chronic neuronal inactivation, which then serves as a nucleation point for transcription factor EB (TFEB) cytonuclear signaling that drives transcription-dependent autophagy for up-scaling. These results provide the first evidence of a physiological role of mTOR-dependent autophagy in enduing neuronal plasticity, thereby connecting major themes in cell biology and neuroscience via a servo loop that mediates autoregulation in the brain.
Collapse
Affiliation(s)
- Yang Wang
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Jingran Lin
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Jiarui Li
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Lu Yan
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Wenwen Li
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Xingzhi He
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
| | - Huan Ma
- Department of Neurobiology, Affiliated Mental Health Center and Hangzhou Seventh People's Hospital, Zhejiang University School of Medicine, Hangzhou 310058, China
- Liangzhu Laboratory, MOE Frontier Science Center for Brain Science and Brain-machine Integration, State Key Laboratory of Brain-machine Intelligence, Zhejiang University, Hangzhou 311121, China
- National Health Commission of the PRC (NHC) and Chinese Academy of Medical Sciences (CAMS) Key Laboratory of Medical Neurobiology, Zhejiang University, Hangzhou 310058, China
- Research Units for Emotion and Emotion disorders, Chinese Academy of Medical Sciences, Beijing 100050, China
| |
Collapse
|
17
|
Sun C, Schuman E. A multi-omics view of neuronal subcellular protein synthesis. Curr Opin Neurobiol 2023; 80:102705. [PMID: 36913750 DOI: 10.1016/j.conb.2023.102705] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 03/13/2023]
Abstract
While it has long been known that protein synthesis is necessary for long-term memory in the brain, the logistics of neuronal protein synthesis is complicated by the extensive subcellular compartmentalization of the neuron. Local protein synthesis solves many of the logistic problems posed by the extreme complexity of dendritic and axonal arbors and the huge number of synapses. Here we review recent multi-omic and quantitative studies that elaborate a systems view of decentralized neuronal protein synthesis. We highlight recent insights from the transcriptomic, translatomic, and proteomic levels, discuss the nuanced logic of local protein synthesis for different protein features, and list the missing information needed to build a comprehensive logistic model for neuronal protein supply.
Collapse
Affiliation(s)
- Chao Sun
- Max Planck Institute for Brain Research, Frankfurt, Germany; Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Denmark; Aarhus University, Department of Molecular Biology and Genetics, Universitetsbyen 81, 8000 Aarhus C, Denmark. https://twitter.com/LukeChaoSun
| | - Erin Schuman
- Max Planck Institute for Brain Research, Frankfurt, Germany.
| |
Collapse
|
18
|
Nabavi M, Hiesinger PR. Turnover of synaptic adhesion molecules. Mol Cell Neurosci 2023; 124:103816. [PMID: 36649812 DOI: 10.1016/j.mcn.2023.103816] [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: 09/30/2022] [Revised: 12/15/2022] [Accepted: 01/10/2023] [Indexed: 01/15/2023] Open
Abstract
Molecular interactions between pre- and postsynaptic membranes play critical roles during the development, function and maintenance of synapses. Synaptic interactions are mediated by cell surface receptors that may be held in place by trans-synaptic adhesion or intracellular binding to membrane-associated scaffolding and signaling complexes. Despite their role in stabilizing synaptic contacts, synaptic adhesion molecules undergo turnover and degradation during all stages of a neuron's life. Here we review current knowledge about membrane trafficking mechanisms that regulate turnover of synaptic adhesion molecules and the functional significance of turnover for synapse development and function. Based on recent proteomics, genetics and imaging studies, synaptic adhesion molecules exhibit remarkably high turnover rates compared to other synaptic proteins. Degradation occurs predominantly via endolysosomal mechanisms, with little evidence for roles of proteasomal or autophagic degradation. Basal turnover occurs both during synaptic development and maintenance. Neuronal activity typically stabilizes synaptic adhesion molecules while downregulating neurotransmitter receptors based on turnover. In conclusion, constitutive turnover of synaptic adhesion molecules is not a necessarily destabilizing factor, but a basis for the dynamic regulation of trans-synaptic interactions during synapse formation and maintenance.
Collapse
Affiliation(s)
- Melinda Nabavi
- Institute for Biology, Division of Neurobiology, Freie Universität Berlin, Germany
| | - P Robin Hiesinger
- Institute for Biology, Division of Neurobiology, Freie Universität Berlin, Germany.
| |
Collapse
|
19
|
Hasan S, Fernandopulle MS, Humble SW, Frankenfield AM, Li H, Prestil R, Johnson KR, Ryan BJ, Wade-Martins R, Ward ME, Hao L. Multi-modal Proteomic Characterization of Lysosomal Function and Proteostasis in Progranulin-Deficient Neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.24.529955. [PMID: 36865171 PMCID: PMC9980118 DOI: 10.1101/2023.02.24.529955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Progranulin (PGRN) is a lysosomal protein implicated in various neurodegenerative diseases. Over 70 mutations discovered in the GRN gene all result in reduced expression of PGRN protein. However, the detailed molecular function of PGRN within lysosomes and the impact of PGRN deficiency on lysosomal biology remain unclear. Here we leveraged multifaceted proteomic techniques to comprehensively characterize how PGRN deficiency changes the molecular and functional landscape of neuronal lysosomes. Using lysosome proximity labeling and immuno-purification of intact lysosomes, we characterized lysosome compositions and interactomes in both human induced pluripotent stem cell (iPSC)-derived glutamatergic neurons (i3Neurons) and mouse brains. Using dynamic stable isotope labeling by amino acids in cell culture (dSILAC) proteomics, we measured global protein half-lives in i3Neurons for the first time and characterized the impact of progranulin deficiency on neuronal proteostasis. Together, this study indicated that PGRN loss impairs the lysosome's degradative capacity with increased levels of v-ATPase subunits on the lysosome membrane, increased catabolic enzymes within the lysosome, elevated lysosomal pH, and pronounced alterations in neuron protein turnover. Collectively, these results suggested PGRN as a critical regulator of lysosomal pH and degradative capacity, which in turn influences global proteostasis in neurons. The multi-modal techniques developed here also provided useful data resources and tools to study the highly dynamic lysosome biology in neurons.
Collapse
Affiliation(s)
- Saadia Hasan
- National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- UK Dementia Research Institute, Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
- MD-PhD program, Augusta University/University of Georgia Medical Partnership, Athens, GA, USA
| | - Michael S. Fernandopulle
- National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
- Medical Scientist Training Program, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Stewart W. Humble
- National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
- Oxford Parkinson’s Disease Centre, Kavli Institute for Nanoscience Discovery, Department of Physiology, Anatomy and Genetics, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | | | - Haorong Li
- Department of Chemistry, George Washington University, Washington, DC, USA
| | - Ryan Prestil
- Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK
| | - Kory R. Johnson
- National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Brent J. Ryan
- Oxford Parkinson’s Disease Centre, Kavli Institute for Nanoscience Discovery, Department of Physiology, Anatomy and Genetics, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Richard Wade-Martins
- Oxford Parkinson’s Disease Centre, Kavli Institute for Nanoscience Discovery, Department of Physiology, Anatomy and Genetics, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Road, Oxford, OX1 3QU UK
| | - Michael E. Ward
- National Institute of Neurological Disorders and Stroke (NINDS), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Ling Hao
- Department of Chemistry, George Washington University, Washington, DC, USA
| |
Collapse
|
20
|
Louros SR, Seo SS, Maio B, Martinez-Gonzalez C, Gonzalez-Lozano MA, Muscas M, Verity NC, Wills JC, Li KW, Nolan MF, Osterweil EK. Excessive proteostasis contributes to pathology in fragile X syndrome. Neuron 2023; 111:508-525.e7. [PMID: 36495869 DOI: 10.1016/j.neuron.2022.11.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Revised: 09/06/2022] [Accepted: 11/16/2022] [Indexed: 12/13/2022]
Abstract
In fragile X syndrome (FX), the leading monogenic cause of autism, excessive neuronal protein synthesis is a core pathophysiology; however, an overall increase in protein expression is not observed. Here, we tested whether excessive protein synthesis drives a compensatory rise in protein degradation that is protective for FX mouse model (Fmr1-/y) neurons. Surprisingly, although we find a significant increase in protein degradation through ubiquitin proteasome system (UPS), this contributes to pathological changes. Normalizing proteasome activity with bortezomib corrects excessive hippocampal protein synthesis and hyperactivation of neurons in the inferior colliculus (IC) in response to auditory stimulation. Moreover, systemic administration of bortezomib significantly reduces the incidence and severity of audiogenic seizures (AGS) in the Fmr1-/y mouse, as does genetic reduction of proteasome, specifically in the IC. Together, these results identify excessive activation of the UPS pathway in Fmr1-/y neurons as a contributor to multiple phenotypes that can be targeted for therapeutic intervention.
Collapse
Affiliation(s)
- Susana R Louros
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Sang S Seo
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Beatriz Maio
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Cristina Martinez-Gonzalez
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Miguel A Gonzalez-Lozano
- Department of Molecular and Cellular Neurobiology, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Melania Muscas
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Nick C Verity
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jimi C Wills
- CRUK Edinburgh Centre, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Centre for Neurogenomics and Cognitive Research, Vrije Universiteit Amsterdam, Amsterdam, the Netherlands
| | - Matthew F Nolan
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Emily K Osterweil
- Centre for Discovery Brain Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK; Simons Initiative for the Developing Brain, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
| |
Collapse
|
21
|
Valakh V, Wise D, Zhu XA, Sha M, Fok J, Van Hooser SD, Schectman R, Cepeda I, Kirk R, O'Toole SM, Nelson SB. A transcriptional constraint mechanism limits the homeostatic response to activity deprivation in mammalian neocortex. eLife 2023; 12:e74899. [PMID: 36749029 PMCID: PMC10010687 DOI: 10.7554/elife.74899] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 02/03/2023] [Indexed: 02/08/2023] Open
Abstract
Healthy neuronal networks rely on homeostatic plasticity to maintain stable firing rates despite changing synaptic drive. These mechanisms, however, can themselves be destabilizing if activated inappropriately or excessively. For example, prolonged activity deprivation can lead to rebound hyperactivity and seizures. While many forms of homeostasis have been described, whether and how the magnitude of homeostatic plasticity is constrained remains unknown. Here, we uncover negative regulation of cortical network homeostasis by the PARbZIP family of transcription factors. In cortical slice cultures made from knockout mice lacking all three of these factors, the network response to prolonged activity withdrawal measured with calcium imaging is much stronger, while baseline activity is unchanged. Whole-cell recordings reveal an exaggerated increase in the frequency of miniature excitatory synaptic currents reflecting enhanced upregulation of recurrent excitatory synaptic transmission. Genetic analyses reveal that two of the factors, Hlf and Tef, are critical for constraining plasticity and for preventing life-threatening seizures. These data indicate that transcriptional activation is not only required for many forms of homeostatic plasticity but is also involved in restraint of the response to activity deprivation.
Collapse
Affiliation(s)
- Vera Valakh
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Derek Wise
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Xiaoyue Aelita Zhu
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Mingqi Sha
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Jaidyn Fok
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Stephen D Van Hooser
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Robin Schectman
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Isabel Cepeda
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Ryan Kirk
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Sean M O'Toole
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| | - Sacha B Nelson
- Department of Biology and Program in Neuroscience, Brandeis UniversityWalthamUnited States
| |
Collapse
|
22
|
Davis BA, Chen HY, Ye Z, Ostlund I, Tippani M, Das D, Sripathy SR, Wang Y, Martin JM, Shim G, Panchwagh NM, Moses RL, Farinelli F, Bohlen JF, Li M, Luikart BW, Jaffe AE, Maher BJ. TCF4 mutations disrupt synaptic function through dysregulation of RIMBP2 in patient-derived cortical neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524788. [PMID: 36712024 PMCID: PMC9882330 DOI: 10.1101/2023.01.19.524788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Genetic variation in the transcription factor 4 ( TCF4) gene is associated with risk for a variety of developmental and psychiatric conditions, which includes a syndromic form of ASD called Pitt Hopkins Syndrome (PTHS). TCF4 encodes an activity-dependent transcription factor that is highly expressed during cortical development and in animal models is shown to regulate various aspects of neuronal development and function. However, our understanding of how disease-causing mutations in TCF4 confer pathophysiology in a human context is lacking. Here we show that cortical neurons derived from patients with TCF4 mutations have deficits in spontaneous synaptic transmission, network excitability and homeostatic plasticity. Transcriptomic analysis indicates these phenotypes result from altered expression of genes involved in presynaptic neurotransmission and identifies the presynaptic binding protein, RIMBP2 as the most differentially expressed gene in PTHS neurons. Remarkably, TCF4-dependent deficits in spontaneous synaptic transmission and network excitability were rescued by increasing RIMBP2 expression in presynaptic neurons. Together, these results identify TCF4 as a critical transcriptional regulator of human synaptic development and plasticity and specifically identifies dysregulation of presynaptic function as an early pathophysiology in PTHS.
Collapse
Affiliation(s)
- Brittany A. Davis
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Huei-Ying Chen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Zengyou Ye
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Isaac Ostlund
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Madhavi Tippani
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Debamitra Das
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Srinidhi Rao Sripathy
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Yanhong Wang
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Jacqueline M. Martin
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Gina Shim
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Neel M. Panchwagh
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Rebecca L. Moses
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Federica Farinelli
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Joseph F. Bohlen
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
| | - Meijie Li
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
| | - Bryan W. Luikart
- Department of Molecular and Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, 03755, USA
| | - Andrew E. Jaffe
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- McKusick-Nathans Institute, Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
- Department of Mental Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Brady J. Maher
- Lieber Institute for Brain Development, Johns Hopkins Medical Campus, Baltimore, MD 21205, USA
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| |
Collapse
|
23
|
Abstract
Cellular protein turnover-the net result of protein synthesis and degradation-is crucial to maintain protein homeostasis and cellular function under steady-state conditions and to enable cells to remodel their proteomes upon a perturbation. In brain cells, proteins are continuously turned over at different rates depending on various factors including cell type, subcellular localization, cellular environment, and neuronal activity. Here we describe a workflow for the analysis of protein synthesis, degradation, and turnover in primary cultured rat neurons and glia using dynamic/pulsed SILAC and mass spectrometry.
Collapse
Affiliation(s)
- Aline R Dörrbaum
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
| | - Julian D Langer
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
- Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| |
Collapse
|
24
|
Sahoo PK, Twiss JL. Profiling Locally Translated mRNAs in Regenerating Axons. Methods Mol Biol 2023; 2636:145-161. [PMID: 36881299 DOI: 10.1007/978-1-0716-3012-9_8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
Spatial and temporal regulation of protein expression plays important roles in many cellular functions, particularly for highly polarized cell types. While the subcellular proteome can be altered by relocalizing proteins from other domains of the cell, transporting mRNAs to subcellular domains provides a means to locally synthesize new proteins in response to different stimuli. Localized protein synthesis is a critical mechanism in neurons that extend dendrites and axons long distances from their cell bodies. Here, we discuss methodologies that have been developed to study localized protein synthesis using axonal protein synthesis as an example. We provide an in-depth method using dual fluorescence recovery after photobleaching to visualize sites of protein synthesis using reporter cDNAs that encode two different localizing mRNAs along with diffusion-limited fluorescent reporter proteins. We show how this method can be used to determine how extracellular stimuli and different physiological states can alter the specificity of local mRNA translation in real time.
Collapse
Affiliation(s)
- Pabitra K Sahoo
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA.
| | - Jeffery L Twiss
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| |
Collapse
|
25
|
Konietzny A, Wegmann S, Mikhaylova M. The endoplasmic reticulum puts a new spin on synaptic tagging. Trends Neurosci 2023; 46:32-44. [PMID: 36428191 DOI: 10.1016/j.tins.2022.10.012] [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: 08/18/2022] [Revised: 10/12/2022] [Accepted: 10/31/2022] [Indexed: 11/23/2022]
Abstract
The heterogeneity of the endoplasmic reticulum (ER) makes it a versatile platform for a broad range of homeostatic processes, ranging from calcium regulation to synthesis and trafficking of proteins and lipids. It is not surprising that neurons use this organelle to fine-tune synaptic properties and thereby provide specificity to synaptic inputs. In this review, we discuss the mechanisms that enable activity-dependent ER recruitment into dendritic spines, with a focus on molecular mechanisms that mediate transport and retention of the ER in spines. The role of calcium signaling in spine ER, synaptopodin 'tagging' of active synapses, and the formation of the spine apparatus (SA) are highlighted. Finally, we discuss the role of liquid-liquid phase separation as a possible driving force in these processes.
Collapse
Affiliation(s)
- Anja Konietzny
- AG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin, Germany; Guest Group 'Neuronal Protein Transport', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Susanne Wegmann
- German Center for Neurodegenerative Diseases (DZNE), Berlin, Germany
| | - Marina Mikhaylova
- AG Optobiology, Institute of Biology, Humboldt Universität zu Berlin, Berlin, Germany; Guest Group 'Neuronal Protein Transport', Center for Molecular Neurobiology, ZMNH, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.
| |
Collapse
|
26
|
Nasseri GG, Matin N, Wild AR, Tosefsky K, Flibotte S, Stacey RG, Hollman RB, Foster LJ, Bamji SX. Synaptic activity-dependent changes in the hippocampal palmitoylome. Sci Signal 2022; 15:eadd2519. [PMID: 36473050 DOI: 10.1126/scisignal.add2519] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Dynamic protein S-palmitoylation is critical for neuronal function, development, and synaptic plasticity. Synaptic activity-dependent changes in palmitoylation have been reported for a small number of proteins. Here, we characterized the palmitoylome in the hippocampi of male mice before and after context-dependent fear conditioning. Of the 121 differentially palmitoylated proteins identified, just over half were synaptic proteins, whereas others were associated with metabolic functions, cytoskeletal organization, and signal transduction. The synapse-associated proteins generally exhibited increased palmitoylation after fear conditioning. In contrast, most of the proteins that exhibited decreased palmitoylation were associated with metabolic processes. Similar results were seen in cultured rat hippocampal neurons in response to chemically induced long-term potentiation. Furthermore, we found that the palmitoylation of one of the synaptic proteins, plasticity-related gene-1 (PRG-1), also known as lipid phosphate phosphatase-related protein type 4 (LPPR4), was important for synaptic activity-induced insertion of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPARs) into the postsynaptic membrane. The findings identify proteins whose dynamic palmitoylation may regulate their role in synaptic plasticity, learning, and memory.
Collapse
Affiliation(s)
- Glory G Nasseri
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Nusrat Matin
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Angela R Wild
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Kira Tosefsky
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Stephane Flibotte
- Life Sciences Institute Bioinformatics Facility, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - R Greg Stacey
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Rocio B Hollman
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Leonard J Foster
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | - Shernaz X Bamji
- Department of Cellular and Physiological Sciences, Life Sciences Institute and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| |
Collapse
|
27
|
Sun C, Schuman EM. Logistics of neuronal protein turnover: Numbers and mechanisms. Mol Cell Neurosci 2022; 123:103793. [PMID: 36396040 DOI: 10.1016/j.mcn.2022.103793] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/07/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
Abstract
Research in the past twenty years or so has revealed that neurons synthesize and degrade proteins at their synapses to enable synaptic proteome remodelling on demand and in real-time. Here we provide a quantitative overview of the decentralized neuronal protein-turnover logistics. We first analyse the huge neuronal protein turnover demand that arises from subcellular compartments outside the cell body, followed by an overview of key quantities and modulation strategies in neuronal protein turnover logistics. In the end, we briefly review recent progress in neuronal local protein synthesis and summarize diverse protein-degradation mechanisms that are found near synapses.
Collapse
Affiliation(s)
- Chao Sun
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany
| | - Erin M Schuman
- Max Planck Institute for Brain Research, 60438 Frankfurt am Main, Germany.
| |
Collapse
|
28
|
Coordinated Regulation of CB1 Cannabinoid Receptors and Anandamide Metabolism Stabilizes Network Activity during Homeostatic Downscaling. eNeuro 2022; 9:ENEURO.0276-22.2022. [PMID: 36316118 PMCID: PMC9663203 DOI: 10.1523/eneuro.0276-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 09/20/2022] [Accepted: 09/28/2022] [Indexed: 12/24/2022] Open
Abstract
Neurons express overlapping homeostatic mechanisms to regulate synaptic function and network properties in response to perturbations of neuronal activity. Endocannabinoids (eCBs) are bioactive lipids synthesized in the postsynaptic compartments to regulate synaptic transmission, plasticity, and neuronal excitability primarily through retrograde activation of presynaptic cannabinoid receptor type 1 (CB1). The eCB system is well situated to regulate neuronal network properties and coordinate presynaptic and postsynaptic activity. However, the role of the eCB system in homeostatic adaptations to neuronal hyperactivity is unknown. To address this issue, we used Western blotting and targeted lipidomics to measure adaptations in eCB system to bicuculline (BCC)-induced chronic hyperexcitation in mature cultured rat cortical neurons, and used multielectrode array (MEA) recording and live-cell imaging of glutamate dynamics to test the effects of pharmacological manipulations of eCB on network activities. We show that BCC-induced chronic hyperexcitation triggers homeostatic downscaling and a coordinated adaptation to enhance tonic eCB signaling. Hyperexcitation triggers first the downregulation of fatty acid amide hydrolase (FAAH), the lipase that degrades the eCB anandamide, then an accumulation of anandamide and related metabolites, and finally a delayed upregulation of surface and total CB1. Additionally, we show that BCC-induced downregulation of surface AMPA-type glutamate receptors (AMPARs) and upregulation of CB1 occur through independent mechanisms. Finally, we show that endocannabinoids support baseline network activities before and after downscaling and is engaged to suppress network activity during adaptation to hyperexcitation. We discuss the implications of our findings in the context of downscaling and homeostatic regulation of in vitro oscillatory network activities.
Collapse
|
29
|
Alzahrani MR, Guan BJ, Zagore LL, Wu J, Chen CW, Licatalosi DD, Baker KE, Hatzoglou M. Newly synthesized mRNA escapes translational repression during the acute phase of the mammalian unfolded protein response. PLoS One 2022; 17:e0271695. [PMID: 35947624 PMCID: PMC9365188 DOI: 10.1371/journal.pone.0271695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/06/2022] [Indexed: 11/19/2022] Open
Abstract
Endoplasmic Reticulum (ER) stress, caused by the accumulation of misfolded proteins in the ER, elicits a homeostatic mechanism known as the Unfolded Protein Response (UPR). The UPR reprograms gene expression to promote adaptation to chronic ER stress. The UPR comprises an acute phase involving inhibition of bulk protein synthesis and a chronic phase of transcriptional induction coupled with the partial recovery of protein synthesis. However, the role of transcriptional regulation in the acute phase of the UPR is not well understood. Here we analyzed the fate of newly synthesized mRNA encoding the protective and homeostatic transcription factor X-box binding protein 1 (XBP1) during this acute phase. We have previously shown that global translational repression induced by the acute UPR was characterized by decreased translation and increased stability of XBP1 mRNA. We demonstrate here that this stabilization is independent of new transcription. In contrast, we show XBP1 mRNA newly synthesized during the acute phase accumulates with long poly(A) tails and escapes translational repression. Inhibition of newly synthesized RNA polyadenylation during the acute phase decreased cell survival with no effect in unstressed cells. Furthermore, during the chronic phase of the UPR, levels of XBP1 mRNA with long poly(A) tails decreased in a manner consistent with co-translational deadenylation. Finally, additional pro-survival, transcriptionally-induced mRNAs show similar regulation, supporting the broad significance of the pre-steady state UPR in translational control during ER stress. We conclude that the biphasic regulation of poly(A) tail length during the UPR represents a previously unrecognized pro-survival mechanism of mammalian gene regulation.
Collapse
Affiliation(s)
- Mohammed R. Alzahrani
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Bo-Jhih Guan
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Leah L. Zagore
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Jing Wu
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Chien-Wen Chen
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Donny D. Licatalosi
- Department of Biochemistry, Case Western Reserve University, Cleveland, Ohio, United States of America
- Center for RNA Science and Therapeutics, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Kristian E. Baker
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Maria Hatzoglou
- Department of Genetics and Genome Sciences, Case Western Reserve University, Cleveland, Ohio, United States of America
| |
Collapse
|
30
|
Sidibe DK, Vogel MC, Maday S. Organization of the autophagy pathway in neurons. Curr Opin Neurobiol 2022; 75:102554. [PMID: 35649324 PMCID: PMC9990471 DOI: 10.1016/j.conb.2022.102554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 03/28/2022] [Accepted: 04/12/2022] [Indexed: 01/18/2023]
Abstract
Macroautophagy (hereafter referred to as autophagy) is an essential quality-control pathway in neurons, which face unique functional and morphological challenges in maintaining the integrity of organelles and the proteome. To overcome these challenges, neurons have developed compartment-specific pathways for autophagy. In this review, we discuss the organization of the autophagy pathway, from autophagosome biogenesis, trafficking, to clearance, in the neuron. We dissect the compartment-specific mechanisms and functions of autophagy in axons, dendrites, and the soma. Furthermore, we highlight examples of how steps along the autophagy pathway are impaired in the context of aging and neurodegenerative disease, which underscore the critical importance of autophagy in maintaining neuronal function and survival.
Collapse
Affiliation(s)
- David K Sidibe
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Maria C Vogel
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Sandra Maday
- Department of Neuroscience, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, 19104, USA.
| |
Collapse
|
31
|
Peinado JR, Chaplot K, Jarvela TS, Barbieri EM, Shorter J, Lindberg I. Sequestration of TDP-43 216-414 Aggregates by Cytoplasmic Expression of the proSAAS Chaperone. ACS Chem Neurosci 2022; 13:1651-1665. [PMID: 35549000 PMCID: PMC9731516 DOI: 10.1021/acschemneuro.2c00156] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
As neurons age, protein homeostasis becomes less efficient, resulting in misfolding and aggregation. Chaperone proteins perform vital functions in the maintenance of cellular proteostasis, and chaperone-based therapies that promote sequestration of toxic aggregates may prove useful in blocking the development of neurodegenerative disease. We previously demonstrated that proSAAS, a small secreted neuronal protein, exhibits potent chaperone activity against protein aggregation in vitro and blocks the cytotoxic effects of amyloid and synuclein oligomers in cell culture systems. We now examine whether cytoplasmic expression of proSAAS results in interactions with protein aggregates in this cellular compartment. We report that expression of proSAAS within the cytoplasm generates dense, membraneless 2 μm proSAAS spheres which progressively fuse to form larger spheres, suggesting liquid droplet-like properties. ProSAAS spheres selectively accumulate a C-terminally truncated fluorescently tagged form of TDP-43, initiating its cellular redistribution; these TDP-43-containing spheres also exhibit dynamic fusion. Efficient encapsulation of TDP-43 into proSAAS spheres is driven by its C-terminal prion-like domain; spheres must be formed for sequestration to occur. Three proSAAS sequences, a predicted coiled-coil, a conserved region (residues 158-169), and the positively charged sequence 181-185, are all required for proSAAS to form spheres able to encapsulate TDP-43 aggregates. Substitution of lysines for arginines in the 181-185 sequence results in nuclear translocation of proSAAS and encapsulation of nuclear-localized TDP-43216-414. As a functional output, we demonstrate that proSAAS expression results in cytoprotection against full-length TDP-43 toxicity in yeast. We conclude that proSAAS can act as a functional holdase for TDP-43 via this phase-separation property, representing a cytoprotectant whose unusual biochemical properties can potentially be exploited in the design of therapeutic molecules.
Collapse
Affiliation(s)
- Juan R. Peinado
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Kriti Chaplot
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Timothy S. Jarvela
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| | - Edward M. Barbieri
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Iris Lindberg
- Department of Anatomy and Neurobiology, University of Maryland School of Medicine, University of Maryland, Baltimore, MD 21201 USA
| |
Collapse
|
32
|
Müller JA, Betzin J, Santos-Tejedor J, Mayer A, Oprişoreanu AM, Engholm-Keller K, Paulußen I, Gulakova P, McGovern TD, Gschossman LJ, Schönhense E, Wark JR, Lamprecht A, Becker AJ, Waardenberg AJ, Graham ME, Dietrich D, Schoch S. A presynaptic phosphosignaling hub for lasting homeostatic plasticity. Cell Rep 2022; 39:110696. [PMID: 35443170 DOI: 10.1016/j.celrep.2022.110696] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/26/2021] [Accepted: 03/29/2022] [Indexed: 11/29/2022] Open
Abstract
Stable function of networks requires that synapses adapt their strength to levels of neuronal activity, and failure to do so results in cognitive disorders. How such homeostatic regulation may be implemented in mammalian synapses remains poorly understood. Here we show that the phosphorylation status of several positions of the active-zone (AZ) protein RIM1 are relevant for synaptic glutamate release. Position RIMS1045 is necessary and sufficient for expression of silencing-induced homeostatic plasticity and is kept phosphorylated by serine arginine protein kinase 2 (SRPK2). SRPK2-induced upscaling of synaptic release leads to additional RIM1 nanoclusters and docked vesicles at the AZ and is not observed in the absence of RIM1 and occluded by RIMS1045E. Our data suggest that SRPK2 and RIM1 represent a presynaptic phosphosignaling hub that is involved in the homeostatic balance of synaptic coupling of neuronal networks.
Collapse
Affiliation(s)
- Johannes Alexander Müller
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Julia Betzin
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Jorge Santos-Tejedor
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Annika Mayer
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Ana-Maria Oprişoreanu
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Kasper Engholm-Keller
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark; Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | | | - Polina Gulakova
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | | | - Lena Johanna Gschossman
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany; Department of Neurosurgery, University Hospital Bonn, Bonn, Germany
| | - Eva Schönhense
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Jesse R Wark
- Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Alf Lamprecht
- Department of Pharmaceutics, Bonn University, Bonn, Germany
| | - Albert J Becker
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany
| | - Ashley J Waardenberg
- Australian Institute for Tropical Health and Medicine, James Cook University, Smithfield, QLD 4878, Australia; i-Synapse, Cairns, QLD, Australia
| | - Mark E Graham
- Synapse Proteomics, Children's Medical Research Institute, The University of Sydney, Westmead, NSW, Australia
| | - Dirk Dietrich
- Department of Neurosurgery, University Hospital Bonn, Bonn, Germany.
| | - Susanne Schoch
- Section for Translational Epilepsy Research, Department of Neuropathology, University Hospital Bonn, Bonn, Germany.
| |
Collapse
|
33
|
Desch K, Schuman EM, Langer JD. Quantifying phosphorylation dynamics in primary neuronal cultures using LC-MS/MS. STAR Protoc 2022; 3:101063. [PMID: 35005645 PMCID: PMC8715330 DOI: 10.1016/j.xpro.2021.101063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cellular processes require tight and coordinated control of protein abundance, localization, and activity. One of the core mechanisms to achieve specific regulation of proteins is protein phosphorylation. Here we present a workflow to monitor protein abundance and phosphorylation in primary cultured neurons using liquid chromatography-coupled mass spectrometry. Our protocol provides a detailed guide on all steps for detection and label-free-quantification of phosphorylated and unmodified proteins of primary cortical neurons, including primary cell culture, phosphoproteomic sample preparation and data-processing, and evaluation. For complete details on the use and execution of this protocol, please refer to Desch et al. (2021).
Collapse
Affiliation(s)
- Kristina Desch
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Erin M. Schuman
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Julian D. Langer
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
- Max Planck Institute of Biophysics, Max von Laue Strasse 3, 60438 Frankfurt, Germany
| |
Collapse
|
34
|
Stabilization of Spine Synaptopodin by mGluR1 Is Required for mGluR-LTD. J Neurosci 2022; 42:1666-1678. [PMID: 35046120 PMCID: PMC8896548 DOI: 10.1523/jneurosci.1466-21.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2021] [Revised: 01/07/2022] [Accepted: 01/10/2022] [Indexed: 02/03/2023] Open
Abstract
Dendritic spines, actin-rich protrusions forming the postsynaptic sites of excitatory synapses, undergo activity-dependent molecular and structural remodeling. Activation of Group 1 metabotropic glutamate receptors (mGluR1 and mGluR5) by synaptic or pharmacological stimulation, induces LTD, but whether this is accompanied with spine elimination remains unresolved. A subset of telencephalic mushroom spines contains the spine apparatus (SA), an enigmatic organelle composed of stacks of smooth endoplasmic reticulum, whose formation depends on the expression of the actin-bundling protein Synaptopodin. Allocation of Synaptopodin to spines appears governed by cell-intrinsic mechanisms as the relative frequency of spines harboring Synaptopodin is conserved in vivo and in vitro Here we show that expression of Synaptopodin/SA in spines is required for induction of mGluR-LTD at Schaffer collateral-CA1 synapses of male mice. Post-mGluR-LTD, mushroom spines lacking Synaptopodin/SA are selectively lost, whereas spines harboring it are preserved. This process, dependent on activation of mGluR1 but not mGluR5, is conserved in mature mouse neurons and rat neurons of both sexes. Mechanistically, we find that mGluR1 supports physical retention of Synaptopodin within excitatory spine synapses during LTD while triggering lysosome-dependent degradation of the protein residing in dendritic shafts. Together, these results reveal a cellular mechanism, dependent on mGluR1, which enables selective preservation of stronger spines containing Synaptopodin/SA while eliminating weaker ones and potentially countering spurious strengthening by de novo recruitment of Synaptopodin. Overall, our results identify spines with Synaptopodin/SA as the locus of mGluR-LTD and underscore the importance of the molecular microanatomy of spines in synaptic plasticity.SIGNIFICANCE STATEMENT Long-term changes in functional synaptic strength are associated with modification of synaptic connectivity through stabilization or elimination of dendritic spines, the postsynaptic locus of excitatory synapses. How heterogeneous spine microanatomy instructs spine remodeling after long-term synaptic depression (LTD) remains unclear. Metabotropic glutamate receptors mGluR1 and mGluR5 induce a form of LTD critical to circuit function in physiological and disease conditions. Our results identify spines containing the protein Synaptopodin, which enables local assembly of a spine apparatus, as the locus of expression of mGluR-LTD and demonstrate a specific role of mGluR1 in promoting selective loss after mGluR-LTD of mature dendritic spines lacking Synaptopodin/spine apparatus. These findings highlight the fundamental contribution of spine microanatomy in selectively enabling functional and structural plasticity.
Collapse
|
35
|
Chronic neuronal excitation leads to dual metaplasticity in the signaling for structural long-term potentiation. Cell Rep 2022; 38:110153. [PMID: 34986356 DOI: 10.1016/j.celrep.2021.110153] [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: 03/18/2021] [Revised: 10/06/2021] [Accepted: 12/01/2021] [Indexed: 11/20/2022] Open
Abstract
Synaptic plasticity is long-lasting changes in synaptic currents and structure. When neurons are exposed to signals that induce aberrant neuronal excitation, they increase the threshold for the induction of long-term potentiation (LTP), known as metaplasticity. However, the metaplastic regulation of structural LTP (sLTP) remains unclear. We investigate glutamate uncaging/photoactivatable (pa)CaMKII-dependent sLTP induction in hippocampal CA1 neurons after chronic neuronal excitation by GABAA receptor antagonists. We find that the neuronal excitation decreases the glutamate uncaging-evoked Ca2+ influx mediated by GluN2B-containing NMDA receptors and suppresses sLTP induction. In addition, single-spine optogenetic stimulation using paCaMKII indicates the suppression of CaMKII signaling. While the inhibition of Ca2+ influx is protein synthesis independent, the paCaMKII-induced sLTP suppression depends on it. Our findings demonstrate that chronic neuronal excitation suppresses sLTP in two independent ways (i.e., dual inhibition of Ca2+ influx and CaMKII signaling). This dual inhibition mechanism may contribute to robust neuronal protection in excitable environments.
Collapse
|
36
|
Lindberg I, Shu Z, Lam H, Helwig M, Yucer N, Laperle A, Svendsen C, Di Monte DA, Maidment NT. The proSAAS Chaperone Provides Neuroprotection and Attenuates Transsynaptic α-Synuclein Spread in Rodent Models of Parkinson's Disease. JOURNAL OF PARKINSON'S DISEASE 2022; 12:1463-1478. [PMID: 35527562 PMCID: PMC9731515 DOI: 10.3233/jpd-213053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
BACKGROUND Parkinson's disease involves aberrant aggregation of the synaptic protein alpha-synuclein (aSyn) in the nigrostriatal tract. We have previously shown that proSAAS, a small neuronal chaperone, blocks aSyn-induced dopaminergic cytotoxicity in primary nigral cultures. OBJECTIVE To determine if proSAAS overexpression is neuroprotective in animal models of Parkinson's disease. METHODS proSAAS- or GFP-encoding lentivirus was injected together with human aSyn-expressing AAV unilaterally into the substantia nigra of rats and motor asymmetry assessed using a battery of motor performance tests. Dopamine neuron survival was assessed by nigral stereology and striatal tyrosine hydroxylase (TH) densitometry. To examine transsynaptic spread of aSyn, aSyn AAV was injected into the vagus of mice in the presence of AAVs encoding either GFP or proSAAS; the spread of aSyn-positive neurites into rostral nuclei was quantified following immunohistochemistry. RESULTS Coinjection of proSAAS-encoding lentivirus profoundly reduced the motor asymmetry caused by unilateral nigral AAV-mediated human aSyn overexpression. This was accompanied by significant amelioration of the human aSyn-induced loss of both nigral TH-positive cells and striatal TH-positive terminals, demonstrating clear proSAAS-mediated protection of the nigrostriatal tract. ProSAAS overexpression reduced human aSyn protein levels in nigra and striatum and reduced the loss of TH protein in both regions. Following vagal administration of human aSyn-encoding AAV, the number of human aSyn-positive neurites in the pons and caudal midbrain was considerably reduced in mice coinjected with proSAAS-, but not GFP-encoding AAV, supporting proSAAS-mediated blockade of transsynaptic aSyn transmission. CONCLUSION The proSAAS chaperone may represent a promising target for therapeutic development in Parkinson's disease.
Collapse
Affiliation(s)
- Iris Lindberg
- University of Maryland-Baltimore;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
| | - Zhan Shu
- University of California-Los Angeles
| | - Hoa Lam
- University of California-Los Angeles
| | | | - Nur Yucer
- Cedars-Sinai Medical Center, Los Angeles
| | | | | | | | - Nigel T. Maidment
- University of California-Los Angeles;,To whom correspondence should be addressed: Iris Lindberg, Ph.D., Department of Anatomy and Neurobiology, University of Maryland Medical School, University of Maryland-Baltimore, Baltimore, MD 21201, Phone: (410) 7064778, and Nigel T. Maidment, Ph.D., Department of Psychiatry and Biobehavioral Sciences, Hatos Center for Neuropharmacology, Semel Institute for Neuroscience and Human Behavior, University of California at Los Angeles, Los Angeles CA 90024, Phone: (310) 206-7767,
| |
Collapse
|
37
|
Wu CH, Tatavarty V, Jean Beltran PM, Guerrero AA, Keshishian H, Krug K, MacMullan MA, Li L, Carr SA, Cottrell JR, Turrigiano GG. A bidirectional switch in the Shank3 phosphorylation state biases synapses toward up- or downscaling. eLife 2022; 11:74277. [PMID: 35471151 PMCID: PMC9084893 DOI: 10.7554/elife.74277] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Accepted: 04/25/2022] [Indexed: 11/13/2022] Open
Abstract
Homeostatic synaptic plasticity requires widespread remodeling of synaptic signaling and scaffolding networks, but the role of post-translational modifications in this process has not been systematically studied. Using deep-scale quantitative analysis of the phosphoproteome in mouse neocortical neurons, we found widespread and temporally complex changes during synaptic scaling up and down. We observed 424 bidirectionally modulated phosphosites that were strongly enriched for synapse-associated proteins, including S1539 in the autism spectrum disorder-associated synaptic scaffold protein Shank3. Using a parallel proteomic analysis performed on Shank3 isolated from rat neocortical neurons by immunoaffinity, we identified two sites that were persistently hypophosphorylated during scaling up and transiently hyperphosphorylated during scaling down: one (rat S1615) that corresponded to S1539 in mouse, and a second highly conserved site, rat S1586. The phosphorylation status of these sites modified the synaptic localization of Shank3 during scaling protocols, and dephosphorylation of these sites via PP2A activity was essential for the maintenance of synaptic scaling up. Finally, phosphomimetic mutations at these sites prevented scaling up but not down, while phosphodeficient mutations prevented scaling down but not up. These mutations did not impact baseline synaptic strength, indicating that they gate, rather than drive, the induction of synaptic scaling. Thus, an activity-dependent switch between hypo- and hyperphosphorylation at S1586 and S1615 of Shank3 enables scaling up or down, respectively. Collectively, our data show that activity-dependent phosphoproteome dynamics are important for the functional reconfiguration of synaptic scaffolds and can bias synapses toward upward or downward homeostatic plasticity.
Collapse
Affiliation(s)
- Chi-Hong Wu
- Department of Biology, Brandeis UniversityWalthamUnited States
| | | | | | | | - Hasmik Keshishian
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Karsten Krug
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Melanie A MacMullan
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Li Li
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Steven A Carr
- Proteomics Platform, Broad Institute of MIT and HarvardCambridgeUnited States
| | - Jeffrey R Cottrell
- Stanley Center for Psychiatric Research, Broad Institute of MIT and HarvardCambridgeUnited States
| | | |
Collapse
|
38
|
Herbst WA, Deng W, Wohlschlegel JA, Achiro JM, Martin KC. Neuronal activity regulates the nuclear proteome to promote activity-dependent transcription. J Cell Biol 2021; 220:e202103087. [PMID: 34617965 PMCID: PMC8504181 DOI: 10.1083/jcb.202103087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 08/23/2021] [Accepted: 09/20/2021] [Indexed: 11/22/2022] Open
Abstract
The formation and plasticity of neuronal circuits relies on dynamic activity-dependent gene expression. Although recent work has revealed the identity of important transcriptional regulators and of genes that are transcribed and translated in response to activity, relatively little is known about the cell biological mechanisms by which activity alters the nuclear proteome of neurons to link neuronal stimulation to transcription. Using nucleus-specific proteomic mapping in silenced and stimulated neurons, we uncovered an understudied mechanism of nuclear proteome regulation: activity-dependent proteasome-mediated degradation. We found that the tumor suppressor protein PDCD4 undergoes rapid stimulus-induced degradation in the nucleus of neurons. We demonstrate that degradation of PDCD4 is required for normal activity-dependent transcription and that PDCD4 target genes include those encoding proteins critical for synapse formation, remodeling, and transmission. Our findings highlight the importance of the nuclear proteasome in regulating the activity-dependent nuclear proteome and point to a specific role for PDCD4 as a regulator of activity-dependent transcription in neurons.
Collapse
Affiliation(s)
- Wendy A. Herbst
- Neuroscience Interdepartmental Program, University of California, Los Angeles, Los Angeles, CA
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA
| | - Weixian Deng
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA
| | - James A. Wohlschlegel
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA
| | - Jennifer M. Achiro
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA
| | - Kelsey C. Martin
- Department of Biological Chemistry, University of California, Los Angeles, Los Angeles, CA
| |
Collapse
|
39
|
Carvalho AL, Fernandes D. It takes two to tango: Concerted protein translation and degradation necessary for synaptic scaling. PLoS Biol 2021; 19:e3001448. [PMID: 34818347 PMCID: PMC8612543 DOI: 10.1371/journal.pbio.3001448] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
This Primer explores the implications of a new study in PLOS Biology which reveals how homeostatic synaptic plasticity requires coordinated and inter-dependent protein synthesis and degradation, as well as remodeling of the miRNA-induced silencing complex.
Collapse
Affiliation(s)
- Ana Luisa Carvalho
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Department of Life Sciences, University of Coimbra, Coimbra, Portugal
- * E-mail:
| | - Dominique Fernandes
- CNC—Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Institute of Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
40
|
Srinivasan B, Samaddar S, Mylavarapu SVS, Clement JP, Banerjee S. Homeostatic scaling is driven by a translation-dependent degradation axis that recruits miRISC remodeling. PLoS Biol 2021; 19:e3001432. [PMID: 34813590 PMCID: PMC8610276 DOI: 10.1371/journal.pbio.3001432] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/30/2021] [Indexed: 01/17/2023] Open
Abstract
Homeostatic scaling in neurons has been attributed to the individual contribution of either translation or degradation; however, there remains limited insight toward understanding how the interplay between the two processes effectuates synaptic homeostasis. Here, we report that a codependence between protein synthesis and degradation mechanisms drives synaptic homeostasis, whereas abrogation of either prevents it. Coordination between the two processes is achieved through the formation of a tripartite complex between translation regulators, the 26S proteasome, and the miRNA-induced silencing complex (miRISC) components such as Argonaute, MOV10, and Trim32 on actively translating transcripts or polysomes. The components of this ternary complex directly interact with each other in an RNA-dependent manner. Disruption of polysomes abolishes this ternary interaction, suggesting that translating RNAs facilitate the combinatorial action of the proteasome and the translational apparatus. We identify that synaptic downscaling involves miRISC remodeling, which entails the mTORC1-dependent translation of Trim32, an E3 ligase, and the subsequent degradation of its target, MOV10 via the phosphorylation of p70 S6 kinase. We find that the E3 ligase Trim32 specifically polyubiquitinates MOV10 for its degradation during synaptic downscaling. MOV10 degradation alone is sufficient to invoke downscaling by enhancing Arc translation through its 3' UTR and causing the subsequent removal of postsynaptic AMPA receptors. Synaptic scaling was occluded when we depleted Trim32 and overexpressed MOV10 in neurons, suggesting that the Trim32-MOV10 axis is necessary for synaptic downscaling. We propose a mechanism that exploits a translation-driven protein degradation paradigm to invoke miRISC remodeling and induce homeostatic scaling during chronic network activity.
Collapse
Affiliation(s)
| | | | | | - James P. Clement
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bengaluru, India
| | | |
Collapse
|
41
|
Abstract
To form synaptic connections and store information, neurons continuously remodel their proteomes. The impressive length of dendrites and axons imposes logistical challenges to maintain synaptic proteins at locations remote from the transcription source (the nucleus). The discovery of thousands of messenger RNAs (mRNAs) near synapses suggested that neurons overcome distance and gain autonomy by producing proteins locally. It is not generally known, however, if, how, and when localized mRNAs are translated into protein. To investigate the translational landscape in neuronal subregions, we performed simultaneous RNA sequencing (RNA-seq) and ribosome sequencing (Ribo-seq) from microdissected rodent brain slices to identify and quantify the transcriptome and translatome in cell bodies (somata) as well as dendrites and axons (neuropil). Thousands of transcripts were differentially translated between somatic and synaptic regions, with many scaffold and signaling molecules displaying increased translation levels in the neuropil. Most translational changes between compartments could be accounted for by differences in RNA abundance. Pervasive translational regulation was observed in both somata and neuropil influenced by specific mRNA features (e.g., untranslated region [UTR] length, RNA-binding protein [RBP] motifs, and upstream open reading frames [uORFs]). For over 800 mRNAs, the dominant source of translation was the neuropil. We constructed a searchable and interactive database for exploring mRNA transcripts and their translation levels in the somata and neuropil [MPI Brain Research, The mRNA translation landscape in the synaptic neuropil. https://public.brain.mpg.de/dashapps/localseq/ Accessed 5 October 2021]. Overall, our findings emphasize the substantial contribution of local translation to maintaining synaptic protein levels and indicate that on-site translational control is an important mechanism to control synaptic strength.
Collapse
|
42
|
Amorim FE, Chapot RL, Moulin TC, Lee JLC, Amaral OB. Memory destabilization during reconsolidation: a consequence of homeostatic plasticity? ACTA ACUST UNITED AC 2021; 28:371-389. [PMID: 34526382 DOI: 10.1101/lm.053418.121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 07/14/2021] [Indexed: 11/24/2022]
Abstract
Remembering is not a static process: When retrieved, a memory can be destabilized and become prone to modifications. This phenomenon has been demonstrated in a number of brain regions, but the neuronal mechanisms that rule memory destabilization and its boundary conditions remain elusive. Using two distinct computational models that combine Hebbian plasticity and synaptic downscaling, we show that homeostatic plasticity can function as a destabilization mechanism, accounting for behavioral results of protein synthesis inhibition upon reactivation with different re-exposure times. Furthermore, by performing systematic reviews, we identify a series of overlapping molecular mechanisms between memory destabilization and synaptic downscaling, although direct experimental links between both phenomena remain scarce. In light of these results, we propose a theoretical framework where memory destabilization can emerge as an epiphenomenon of homeostatic adaptations prompted by memory retrieval.
Collapse
Affiliation(s)
- Felippe E Amorim
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Renata L Chapot
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| | - Thiago C Moulin
- Functional Pharmacology Unit, Department of Neuroscience, Uppsala University, Uppsala 751 24, Sweden
| | - Jonathan L C Lee
- University of Birmingham, School of Psychology, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Olavo B Amaral
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro 21941-902, Brazil
| |
Collapse
|
43
|
Giandomenico SL, Alvarez-Castelao B, Schuman EM. Proteostatic regulation in neuronal compartments. Trends Neurosci 2021; 45:41-52. [PMID: 34489114 DOI: 10.1016/j.tins.2021.08.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 07/16/2021] [Accepted: 08/05/2021] [Indexed: 12/16/2022]
Abstract
Neurons continuously adapt to external cues and challenges, including stimulation, plasticity-inducing signals and aging. These adaptations are critical for neuronal physiology and extended survival. Proteostasis is the process by which cells adjust their protein content to achieve the specific protein repertoire necessary for cellular function. Due to their complex morphology and polarized nature, neurons possess unique proteostatic requirements. Proteostatic control in axons and dendrites must be implemented through regulation of protein synthesis and degradation in a decentralized fashion, but at the same time, it requires integration, at least in part, in the soma. Here, we discuss current understanding of neuronal proteostasis, as well as open questions and future directions requiring further exploration.
Collapse
Affiliation(s)
| | - Beatriz Alvarez-Castelao
- Department of Biochemistry and Molecular Biology, Veterinary School, Complutense University of Madrid, Madrid, Spain
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Frankfurt am Main, Germany.
| |
Collapse
|
44
|
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.
Collapse
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;
| |
Collapse
|
45
|
Desch K, Langer JD, Schuman EM. Dynamic bi-directional phosphorylation events associated with the reciprocal regulation of synapses during homeostatic up- and down-scaling. Cell Rep 2021; 36:109583. [PMID: 34433048 PMCID: PMC8411114 DOI: 10.1016/j.celrep.2021.109583] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 06/15/2021] [Accepted: 07/29/2021] [Indexed: 01/17/2023] Open
Abstract
Homeostatic synaptic scaling allows for bi-directional adjustment of the strength of synaptic connections in response to changes in their input. Protein phosphorylation modulates many neuronal processes, but it has not been studied on a global scale during synaptic scaling. Here, we use liquid chromatography-tandem mass spectrometry (LC-MS/MS) analyses to measure changes in the phosphoproteome in response to up- or down-scaling in cultured cortical neurons over minutes to 24 h. Of ~45,000 phosphorylation events, ~3,300 (associated with 1,285 phosphoproteins) are regulated by homeostatic scaling. Activity-sensitive phosphoproteins are predominantly located at synapses and involved in cytoskeletal reorganization. We identify many early phosphorylation events that could serve as sensors for the activity offset as well as late and/or persistent phosphoregulation that could represent effector mechanisms driving the homeostatic response. Much of the persistent phosphorylation is reciprocally regulated by up- or down-scaling, suggesting that mechanisms underlying these two poles of synaptic regulation make use of a common signaling axis. Global proteome and phosphoproteome dynamics following homeostatic synaptic scaling Approximately 3,300 activity-sensitive, synapse-associated phospho-events Persistent signaling of ~25% of initial phospho-events (min to 24 h) Persistent and reciprocal phosphoregulation links synaptic up- and down-scaling
Collapse
Affiliation(s)
- Kristina Desch
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany
| | - Julian D Langer
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany.
| | - Erin M Schuman
- Max Planck Institute for Brain Research, Max von Laue Strasse 4, 60438 Frankfurt, Germany.
| |
Collapse
|
46
|
Colameo D, Rajman M, Soutschek M, Bicker S, von Ziegler L, Bohacek J, Winterer J, Germain PL, Dieterich C, Schratt G. Pervasive compartment-specific regulation of gene expression during homeostatic synaptic scaling. EMBO Rep 2021; 22:e52094. [PMID: 34396684 PMCID: PMC8490987 DOI: 10.15252/embr.202052094] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 07/12/2021] [Accepted: 07/20/2021] [Indexed: 12/13/2022] Open
Abstract
Synaptic scaling is a form of homeostatic plasticity which allows neurons to adjust their action potential firing rate in response to chronic alterations in neural activity. Synaptic scaling requires profound changes in gene expression, but the relative contribution of local and cell‐wide mechanisms is controversial. Here we perform a comprehensive multi‐omics characterization of the somatic and process compartments of primary rat hippocampal neurons during synaptic scaling. We uncover both highly compartment‐specific and correlating changes in the neuronal transcriptome and proteome. Whereas downregulation of crucial regulators of neuronal excitability occurs primarily in the somatic compartment, structural components of excitatory postsynapses are mostly downregulated in processes. Local inhibition of protein synthesis in processes during scaling is confirmed for candidate synaptic proteins. Motif analysis further suggests an important role for trans‐acting post‐transcriptional regulators, including RNA‐binding proteins and microRNAs, in the local regulation of the corresponding mRNAs. Altogether, our study indicates that, during synaptic scaling, compartmentalized gene expression changes might co‐exist with neuron‐wide mechanisms to allow synaptic computation and homeostasis.
Collapse
Affiliation(s)
- David Colameo
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Marek Rajman
- Institute for Physiological Chemistry, Biochemical-Pharmacological Center Marburg, Philipps-University of Marburg, Marburg, Germany
| | - Michael Soutschek
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Silvia Bicker
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Lukas von Ziegler
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland.,Laboratory of Behavioural and Molecular Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland
| | - Johannes Bohacek
- Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland.,Laboratory of Behavioural and Molecular Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland
| | - Jochen Winterer
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| | - Pierre-Luc Germain
- Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Laboratory of Statistical Bioinformatics, Department of Molecular Life Sciences, University of Zürich, Zurich, Switzerland
| | - Christoph Dieterich
- Section of Bioinformatics and Systems Cardiology, Department of Internal Medicine III and Klaus Tschira Institute for Integrative Computational Cardiology, University of Heidelberg, Heidelberg, Germany
| | - Gerhard Schratt
- Laboratory of Systems Neuroscience, Institute for Neuroscience, Department of Health Science and Technology, Swiss Federal Institute of Technology ETH, Zurich, Switzerland.,Neuroscience Center Zurich, ETH Zurich and University of Zurich, Zurich, Switzerland
| |
Collapse
|
47
|
van Bergen W, Heck AJR, Baggelaar MP. Recent advancements in mass spectrometry-based tools to investigate newly synthesized proteins. Curr Opin Chem Biol 2021; 66:102074. [PMID: 34364788 PMCID: PMC9548413 DOI: 10.1016/j.cbpa.2021.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/28/2021] [Accepted: 07/03/2021] [Indexed: 02/08/2023]
Abstract
Tight regulation of protein translation drives the proteome to undergo changes under influence of extracellular or intracellular signals. Despite mass spectrometry–based proteomics being an excellent method to study differences in protein abundance in complex proteomes, analyzing minute or rapid changes in protein synthesis and abundance remains challenging. Therefore, several dedicated techniques to directly detect and quantify newly synthesized proteins have been developed, notably puromycin-based, bio-orthogonal noncanonical amino acid tagging–based, and stable isotope labeling by amino acids in cell culture–based methods, combined with mass spectrometry. These techniques have enabled the investigation of perturbations, stress, or stimuli on protein synthesis. Improvements of these methods are still necessary to overcome various remaining limitations. Recent improvements include enhanced enrichment approaches and combinations with various stable isotope labeling techniques, which allow for more accurate analysis and comparison between conditions on shorter timeframes and in more challenging systems. Here, we aim to review the current state in this field.
Collapse
Affiliation(s)
- Wouter van Bergen
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, Utrecht, 3584 CH, the Netherlands; Netherlands Proteomics Center, Padualaan 8, Utrecht, 3584 CH, the Netherlands
| | - Albert J R Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, Utrecht, 3584 CH, the Netherlands; Netherlands Proteomics Center, Padualaan 8, Utrecht, 3584 CH, the Netherlands
| | - Marc P Baggelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, University of Utrecht, Padualaan 8, Utrecht, 3584 CH, the Netherlands; Netherlands Proteomics Center, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
| |
Collapse
|
48
|
Matthews PM, Pinggera A, Kampjut D, Greger IH. Biology of AMPA receptor interacting proteins - From biogenesis to synaptic plasticity. Neuropharmacology 2021; 197:108709. [PMID: 34271020 DOI: 10.1016/j.neuropharm.2021.108709] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/19/2021] [Accepted: 07/08/2021] [Indexed: 12/19/2022]
Abstract
AMPA-type glutamate receptors mediate the majority of excitatory synaptic transmission in the central nervous system. Their signaling properties and abundance at synapses are both crucial determinants of synapse efficacy and plasticity, and are therefore under sophisticated control. Unique to this ionotropic glutamate receptor (iGluR) is the abundance of interacting proteins that contribute to its complex regulation. These include transient interactions with the receptor cytoplasmic tail as well as the N-terminal domain locating to the synaptic cleft, both of which are involved in AMPAR trafficking and receptor stabilization at the synapse. Moreover, an array of transmembrane proteins operate as auxiliary subunits that in addition to receptor trafficking and stabilization also substantially impact AMPAR gating and pharmacology. Here, we provide an overview of the catalogue of AMPAR interacting proteins, and how they contribute to the complex biology of this central glutamate receptor.
Collapse
Affiliation(s)
- Peter M Matthews
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Alexandra Pinggera
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Domen Kampjut
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Ingo H Greger
- Neurobiology Division, MRC Laboratory of Molecular Biology, Cambridge, UK.
| |
Collapse
|
49
|
Yousefi R, Jevdokimenko K, Kluever V, Pacheu-Grau D, Fornasiero EF. Influence of Subcellular Localization and Functional State on Protein Turnover. Cells 2021; 10:cells10071747. [PMID: 34359917 PMCID: PMC8306977 DOI: 10.3390/cells10071747] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 07/02/2021] [Accepted: 07/07/2021] [Indexed: 12/14/2022] Open
Abstract
Protein homeostasis is an equilibrium of paramount importance that maintains cellular performance by preserving an efficient proteome. This equilibrium avoids the accumulation of potentially toxic proteins, which could lead to cellular stress and death. While the regulators of proteostasis are the machineries controlling protein production, folding and degradation, several other factors can influence this process. Here, we have considered two factors influencing protein turnover: the subcellular localization of a protein and its functional state. For this purpose, we used an imaging approach based on the pulse-labeling of 17 representative SNAP-tag constructs for measuring protein lifetimes. With this approach, we obtained precise measurements of protein turnover rates in several subcellular compartments. We also tested a selection of mutants modulating the function of three extensively studied proteins, the Ca2+ sensor calmodulin, the small GTPase Rab5a and the brain creatine kinase (CKB). Finally, we followed up on the increased lifetime observed for the constitutively active Rab5a (Q79L), and we found that its stabilization correlates with enlarged endosomes and increased interaction with membranes. Overall, our data reveal that both changes in protein localization and functional state are key modulators of protein turnover, and protein lifetime fluctuations can be considered to infer changes in cellular behavior.
Collapse
Affiliation(s)
- Roya Yousefi
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073 Göttingen, Germany;
| | - Kristina Jevdokimenko
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
| | - Verena Kluever
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
| | - David Pacheu-Grau
- Department of Cellular Biochemistry, University Medical Center Göttingen, 37073 Göttingen, Germany;
| | - Eugenio F. Fornasiero
- Department of Neuro- and Sensory Physiology, University Medical Center Göttingen, 37073 Göttingen, Germany; (R.Y.); (K.J.); (V.K.)
- Correspondence:
| |
Collapse
|
50
|
Kharod SC, Hwang DW, Das S, Yoon YJ. Spatiotemporal Insights Into RNA-Organelle Interactions in Neurons. Front Cell Dev Biol 2021; 9:663367. [PMID: 34178987 PMCID: PMC8222803 DOI: 10.3389/fcell.2021.663367] [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: 02/02/2021] [Accepted: 05/04/2021] [Indexed: 01/03/2023] Open
Abstract
Neurons exhibit spatial compartmentalization of gene expression where localization of messenger RNAs (mRNAs) to distal processes allows for site-specific distribution of proteins through local translation. Recently, there have been reports of coordination between mRNA transport with vesicular and organellar trafficking. In this review, we will highlight the latest literature on axonal and dendritic local protein synthesis with links to mRNA-organelle cotransport followed by emerging technologies necessary to study these phenomena. Recent high-resolution imaging studies have led to insights into the dynamics of RNA-organelle interactions, and we can now peer into these intricate interactions within subcellular compartments of neurons.
Collapse
Affiliation(s)
- Shivani C. Kharod
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Dong-Woo Hwang
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Sulagna Das
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, United States
| | - Young J. Yoon
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, United States
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY, United States
| |
Collapse
|