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Odierna GL, Vucic S, Dyer M, Dickson T, Woodhouse A, Blizzard C. How do we get from hyperexcitability to excitotoxicity in amyotrophic lateral sclerosis? Brain 2024; 147:1610-1621. [PMID: 38408864 PMCID: PMC11068114 DOI: 10.1093/brain/awae039] [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: 07/17/2023] [Revised: 11/15/2023] [Accepted: 12/10/2023] [Indexed: 02/28/2024] Open
Abstract
Amyotrophic lateral sclerosis is a devastating neurodegenerative disease that, at present, has no effective cure. Evidence of increased circulating glutamate and hyperexcitability of the motor cortex in patients with amyotrophic lateral sclerosis have provided an empirical support base for the 'dying forward' excitotoxicity hypothesis. The hypothesis postulates that increased activation of upper motor neurons spreads pathology to lower motor neurons in the spinal cord in the form of excessive glutamate release, which triggers excitotoxic processes. Many clinical trials have focused on therapies that target excitotoxicity via dampening neuronal activation, but not all are effective. As such, there is a growing tension between the rising tide of evidence for the 'dying forward' excitotoxicity hypothesis and the failure of therapies that target neuronal activation. One possible solution to these contradictory outcomes is that our interpretation of the current evidence requires revision in the context of appreciating the complexity of the nervous system and the limitations of the neurobiological assays we use to study it. In this review we provide an evaluation of evidence relevant to the 'dying forward' excitotoxicity hypothesis and by doing so, identify key gaps in our knowledge that need to be addressed. We hope to provide a road map from hyperexcitability to excitotoxicity so that we can better develop therapies for patients suffering from amyotrophic lateral sclerosis. We conclude that studies of upper motor neuron activity and their synaptic output will play a decisive role in the future of amyotrophic lateral sclerosis therapy.
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Affiliation(s)
- G Lorenzo Odierna
- Tasmanian School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
| | - Steve Vucic
- Brain and Nerve Research Center, The University of Sydney, Sydney 2050, Australia
| | - Marcus Dyer
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
- Department of Pharmaceutical and Pharmacological Sciences, Center for Neurosciences, Vrije Universiteit Brussel (VUB), 1090 Brussels, Belgium
| | - Tracey Dickson
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
| | - Adele Woodhouse
- The Wicking Dementia Centre, University of Tasmania, Hobart, TAS 7000, Australia
| | - Catherine Blizzard
- Tasmanian School of Medicine, University of Tasmania, Hobart, TAS 7000, Australia
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia
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2
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Assoni AF, Guerrero EN, Wardenaar R, Oliveira D, Bakker PL, Alves LM, Carvalho VM, Okamoto OK, Zatz M, Foijer F. IFNγ protects motor neurons from oxidative stress via enhanced global protein synthesis in FUS-associated amyotrophic lateral sclerosis. Brain Pathol 2024; 34:e13206. [PMID: 37582053 PMCID: PMC10711262 DOI: 10.1111/bpa.13206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 07/12/2023] [Indexed: 08/17/2023] Open
Abstract
Amyotrophic lateral sclerosis type 6 (ALS6) is a familial subtype of ALS linked to Fused in Sarcoma (FUS) gene mutation. FUS mutations lead to decreased global protein synthesis, but the mechanism that drives this has not been established. Here, we used ALS6 patient-derived induced pluripotent stem cells (hIPSCs) to study the effect of the ALS6 FUSR521H mutation on the translation machinery in motor neurons (MNs). We find, in agreement with findings of others, that protein synthesis is decreased in FUSR521H MNs. Furthermore, FUSR521H MNs are more sensitive to oxidative stress and display reduced expression of TGF-β and mTORC gene pathways when stressed. Finally, we show that IFNγ treatment reduces apoptosis of FUSR521H MNs exposed to oxidative stress and partially restores the translation rates in FUSR521H MNs. Overall, these findings suggest that a functional IFNγ response is important for FUS-mediated protein synthesis, possibly by FUS nuclear translocation in ALS6.
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Affiliation(s)
- Amanda Faria Assoni
- European Research Institute for the Biology of Ageing (ERIBA)University of Groningen, University Medical Center GroningenGroningenThe Netherlands
- Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | - Erika N. Guerrero
- European Research Institute for the Biology of Ageing (ERIBA)University of Groningen, University Medical Center GroningenGroningenThe Netherlands
- Department of Stem Cell ResearchGorgas Memorial Institute for Health StudiesPanama CityRepublic of Panama
| | - René Wardenaar
- European Research Institute for the Biology of Ageing (ERIBA)University of Groningen, University Medical Center GroningenGroningenThe Netherlands
| | - Danyllo Oliveira
- Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | - Petra L. Bakker
- European Research Institute for the Biology of Ageing (ERIBA)University of Groningen, University Medical Center GroningenGroningenThe Netherlands
| | - Luciana M. Alves
- Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | | | | | - Mayana Zatz
- Instituto de BiociênciasUniversidade de São PauloSão PauloBrazil
| | - Floris Foijer
- European Research Institute for the Biology of Ageing (ERIBA)University of Groningen, University Medical Center GroningenGroningenThe Netherlands
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3
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Kim SC, Mitchell SJ, Qamar S, Whitcomb DJ, Ruepp MD, St George-Hyslop P, Cho K. Mimicking hypomethylation of FUS requires liquid-liquid phase separation to induce synaptic dysfunctions. Acta Neuropathol Commun 2023; 11:199. [PMID: 38105257 PMCID: PMC10726623 DOI: 10.1186/s40478-023-01703-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 11/29/2023] [Indexed: 12/19/2023] Open
Abstract
The hypomethylation of fused in sarcoma (FUS) in frontotemporal lobar degeneration promotes the formation of irreversible condensates of FUS. However, the mechanisms by which these hypomethylated FUS condensates cause neuronal dysfunction are unknown. Here we report that expression of FUS constructs mimicking hypomethylated FUS causes aberrant dendritic FUS condensates in CA1 neurons. These hypomethylated FUS condensates exhibit spontaneous, and activity induced movement within the dendrite. They impair excitatory synaptic transmission, postsynaptic density-95 expression, and dendritic spine plasticity. These neurophysiological defects are dependent upon both the dendritic localisation of the condensates, and their ability to undergo liquid-liquid phase separation. These results indicate that the irreversible liquid-liquid phase separation is a key component of hypomethylated FUS pathophysiology in sporadic FTLD, and this can cause synapse dysfunction in sporadic FTLD.
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Affiliation(s)
- Seung Chan Kim
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, UK-Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 9NU, UK
| | - Scott J Mitchell
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, UK-Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 9NU, UK
| | - Seema Qamar
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
| | | | - Marc-David Ruepp
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, UK-Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 9NU, UK
| | - Peter St George-Hyslop
- Department of Clinical Neurosciences, Cambridge Institute for Medical Research, University of Cambridge, Cambridge, CB2 0XY, UK
- Department of Medicine (Division of Neurology), University Health Network and Tanz Centre for Research In Neurodegenerative Diseases, Temerty Faculty of Medicine, University of Toronto, Toronto, ON, M5S 3H2, Canada
- Taub Institute For Research On Alzheimer's Disease and the Aging Brain, Department of Neurology, Columbia University Irving Medical Center, 630 West 168 Street, New York, NY, 10032, USA
| | - Kwangwook Cho
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, UK-Dementia Research Institute, Maurice Wohl Clinical Neuroscience Institute, King's College London, London, SE5 9NU, UK.
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4
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Aly A, Laszlo ZI, Rajkumar S, Demir T, Hindley N, Lamont DJ, Lehmann J, Seidel M, Sommer D, Franz-Wachtel M, Barletta F, Heumos S, Czemmel S, Kabashi E, Ludolph A, Boeckers TM, Henstridge CM, Catanese A. Integrative proteomics highlight presynaptic alterations and c-Jun misactivation as convergent pathomechanisms in ALS. Acta Neuropathol 2023; 146:451-475. [PMID: 37488208 PMCID: PMC10412488 DOI: 10.1007/s00401-023-02611-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/05/2023] [Accepted: 07/06/2023] [Indexed: 07/26/2023]
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a fatal neurodegenerative disease mainly affecting upper and lower motoneurons. Several functionally heterogeneous genes have been associated with the familial form of this disorder (fALS), depicting an extremely complex pathogenic landscape. This heterogeneity has limited the identification of an effective therapy, and this bleak prognosis will only improve with a greater understanding of convergent disease mechanisms. Recent evidence from human post-mortem material and diverse model systems has highlighted the synapse as a crucial structure actively involved in disease progression, suggesting that synaptic aberrations might represent a shared pathological feature across the ALS spectrum. To test this hypothesis, we performed the first comprehensive analysis of the synaptic proteome from post-mortem spinal cord and human iPSC-derived motoneurons carrying mutations in the major ALS genes. This integrated approach highlighted perturbations in the molecular machinery controlling vesicle release as a shared pathomechanism in ALS. Mechanistically, phosphoproteomic analysis linked the presynaptic vesicular phenotype to an accumulation of cytotoxic protein aggregates and to the pro-apoptotic activation of the transcription factor c-Jun, providing detailed insights into the shared pathobiochemistry in ALS. Notably, sub-chronic treatment of our iPSC-derived motoneurons with the fatty acid docosahexaenoic acid exerted a neuroprotective effect by efficiently rescuing the alterations revealed by our multidisciplinary approach. Together, this study provides strong evidence for the central and convergent role played by the synaptic microenvironment within the ALS spinal cord and highlights a potential therapeutic target that counteracts degeneration in a heterogeneous cohort of human motoneuron cultures.
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Affiliation(s)
- Amr Aly
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Zsofia I Laszlo
- Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK
| | - Sandeep Rajkumar
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Tugba Demir
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Nicole Hindley
- Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK
| | - Douglas J Lamont
- FingerPrints Proteomics Facility, Discovery Centre, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Johannes Lehmann
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Mira Seidel
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | - Daniel Sommer
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
| | | | - Francesca Barletta
- Quantitative Biology Center (QBiC), University of Tübingen, 72076, Tübingen, Germany
| | - Simon Heumos
- Quantitative Biology Center (QBiC), University of Tübingen, 72076, Tübingen, Germany
- Biomedical Data Science, Department of Computer Science, University of Tübingen, 72076, Tübingen, Germany
| | - Stefan Czemmel
- Quantitative Biology Center (QBiC), University of Tübingen, 72076, Tübingen, Germany
| | - Edor Kabashi
- Laboratory of Translational Research for Neurological Disorders, Imagine Institute, Université de Paris, INSERM, UMR 1163, 75015, Paris, France
| | - Albert Ludolph
- Department of Neurology, Ulm University School of Medicine, Ulm, Germany
- German Center for Neurodegenerative Diseases (DZNE), Ulm Site, Germany
| | - Tobias M Boeckers
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany
- German Center for Neurodegenerative Diseases (DZNE), Ulm Site, Germany
| | - Christopher M Henstridge
- Division of Cellular and Systems Medicine, School of Medicine, University of Dundee, Dundee, Scotland, UK.
| | - Alberto Catanese
- Institute of Anatomy and Cell Biology, Ulm University, Ulm, Germany.
- German Center for Neurodegenerative Diseases (DZNE), Ulm Site, Germany.
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5
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Broadhead MJ, Ayvazian-Hancock A, Doucet K, Kantelberg O, Motherwell L, Zhu F, Grant SGN, Horrocks MH, Miles GB. Synaptic expression of TAR-DNA-binding protein 43 in the mouse spinal cord determined using super-resolution microscopy. Front Mol Neurosci 2023; 16:1027898. [PMID: 37671010 PMCID: PMC10475998 DOI: 10.3389/fnmol.2023.1027898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 06/22/2023] [Indexed: 09/07/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is characterised by a loss of motor neurons in the brain and spinal cord that is preceded by early-stage changes in synapses that may be associated with TAR-DNA-Binding Protein 43 (TDP-43) pathology. Cellular inclusions of hyperphosphorylated TDP-43 (pTDP-43) are a key hallmark of neurodegenerative diseases such ALS. However, there has been little characterisation of the synaptic expression of TDP-43 inside subpopulations of spinal cord synapses. This study utilises a range of high-resolution and super-resolution microscopy techniques with immunolabelling, as well as an aptamer-based TDP-43 labelling strategy visualised with single-molecule localisation microscopy, to characterise and quantify the presence of pTDP-43 in populations of excitatory synapses near where motor neurons reside in the lateral ventral horn of the mouse lumbar spinal cord. We observe that TDP-43 is expressed in approximately half of spinal cord synapses as nanoscale clusters. Synaptic TDP-43 clusters are found most abundantly at synapses associated with VGLUT1-positive presynaptic terminals, compared to VGLUT2-associated synapses. Our nanoscopy techniques showed no difference in the subsynaptic expression of pTDP-43 in the ALS mouse model, SOD1G93a, compared to healthy controls, despite prominent structural deficits in VGLUT1-associated synapses in SOD1G93a mice. This research characterises the basic synaptic expression of TDP-43 with nanoscale precision and provides a framework with which to investigate the potential relationship between TDP-43 pathology and synaptic pathology in neurodegenerative diseases.
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Affiliation(s)
- Matthew J. Broadhead
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
- Edinburgh Super-Resolution Imaging Consortium, Heriot-Watt University, Edinburgh, United Kingdom
| | - Ani Ayvazian-Hancock
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Katherine Doucet
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Owen Kantelberg
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
| | - Lesley Motherwell
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
- Centre of Biophotonics, University of St. Andrews, St. Andrews, United Kingdom
| | - Fei Zhu
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Seth G. N. Grant
- Genes to Cognition Program, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
- Simons Initiative for the Developing Brain (SIDB), Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Mathew H. Horrocks
- EaStCHEM School of Chemistry, University of Edinburgh, Edinburgh, United Kingdom
- IRR Chemistry Hub, Institute for Regeneration and Repair, University of Edinburgh, Edinburgh, United Kingdom
| | - Gareth B. Miles
- School of Psychology and Neuroscience, University of St. Andrews, St. Andrews, United Kingdom
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6
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Kandhavivorn W, Glaß H, Herrmannsdörfer T, Böckers TM, Uhlarz M, Gronemann J, Funk RHW, Pietzsch J, Pal A, Hermann A. Restoring Axonal Organelle Motility and Regeneration in Cultured FUS-ALS Motoneurons through Magnetic Field Stimulation Suggests an Alternative Therapeutic Approach. Cells 2023; 12:1502. [PMID: 37296623 PMCID: PMC10252208 DOI: 10.3390/cells12111502] [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: 03/09/2023] [Revised: 05/17/2023] [Accepted: 05/22/2023] [Indexed: 06/12/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating motoneuron disease characterized by sustained loss of neuromuscular junctions, degenerating corticospinal motoneurons and rapidly progressing muscle paralysis. Motoneurons have unique features, essentially a highly polarized, lengthy architecture of axons, posing a considerable challenge for maintaining long-range trafficking routes for organelles, cargo, mRNA and secretion with a high energy effort to serve crucial neuronal functions. Impaired intracellular pathways implicated in ALS pathology comprise RNA metabolism, cytoplasmic protein aggregation, cytoskeletal integrity for organelle trafficking and maintenance of mitochondrial morphology and function, cumulatively leading to neurodegeneration. Current drug treatments only have marginal effects on survival, thereby calling for alternative ALS therapies. Exposure to magnetic fields, e.g., transcranial magnetic stimulations (TMS) on the central nervous system (CNS), has been broadly explored over the past 20 years to investigate and improve physical and mental activities through stimulated excitability as well as neuronal plasticity. However, studies of magnetic treatments on the peripheral nervous system are still scarce. Thus, we investigated the therapeutic potential of low frequency alternating current magnetic fields on cultured spinal motoneurons derived from induced pluripotent stem cells of FUS-ALS patients and healthy persons. We report a remarkable restoration induced by magnetic stimulation on axonal trafficking of mitochondria and lysosomes and axonal regenerative sprouting after axotomy in FUS-ALS in vitro without obvious harmful effects on diseased and healthy neurons. These beneficial effects seem to derive from improved microtubule integrity. Thus, our study suggests the therapeutic potential of magnetic stimulations in ALS, which awaits further exploration and validation in future long-term in vivo studies.
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Affiliation(s)
- Wonphorn Kandhavivorn
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
- Institute of Anatomy, Technische Universität Dresden, D-01307 Dresden, Germany
| | - Hannes Glaß
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
- Translational Neurodegeneration Section “Albrecht Kossel”, Department of Neurology, University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
| | - Thomas Herrmannsdörfer
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Tobias M. Böckers
- Institute of Anatomy and Cell Biology, University of Ulm, D-89081 Ulm, Germany;
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Ulm, D-89081 Ulm, Germany
| | - Marc Uhlarz
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Jonas Gronemann
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
| | - Richard H. W. Funk
- Institute of Anatomy, Technische Universität Dresden, D-01307 Dresden, Germany
- Dresden International University, D-01067 Dresden, Germany
| | - Jens Pietzsch
- Department of Radiopharmaceutical and Chemical Biology, Institute of Radiopharmaceutical Cancer Research, Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany
- Faculty of Chemistry and Food Chemistry, School of Science, Technische Universität Dresden, D-01069 Dresden, Germany
| | - Arun Pal
- Dresden High Magnetic Field Laboratory (HLD-EMFL), Helmholtz-Zentrum Dresden-Rossendorf, D-01328 Dresden, Germany; (W.K.); (T.H.); (M.U.); (J.G.)
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
| | - Andreas Hermann
- Division for Neurodegenerative Diseases, Department of Neurology, Technische Universität Dresden, D-01307 Dresden, Germany;
- Translational Neurodegeneration Section “Albrecht Kossel”, Department of Neurology, University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE) Rostock/Greifswald, D-18147 Rostock, Germany
- Center for Transdisciplinary Neurosciences Rostock (CTNR), University Medical Center Rostock, University of Rostock, D-18147 Rostock, Germany
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7
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Woelfle S, Deshpande D, Feldengut S, Braak H, Del Tredici K, Roselli F, Deisseroth K, Michaelis J, Boeckers TM, Schön M. CLARITY increases sensitivity and specificity of fluorescence immunostaining in long-term archived human brain tissue. BMC Biol 2023; 21:113. [PMID: 37221592 PMCID: PMC10207789 DOI: 10.1186/s12915-023-01582-6] [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: 09/15/2022] [Accepted: 03/29/2023] [Indexed: 05/25/2023] Open
Abstract
BACKGROUND Post mortem human brain tissue is an essential resource to study cell types, connectivity as well as subcellular structures down to the molecular setup of the central nervous system especially with respect to the plethora of brain diseases. A key method is immunostaining with fluorescent dyes, which allows high-resolution imaging in three dimensions of multiple structures simultaneously. Although there are large collections of formalin-fixed brains, research is often limited because several conditions arise that complicate the use of human brain tissue for high-resolution fluorescence microscopy. RESULTS In this study, we developed a clearing approach for immunofluorescence-based analysis of perfusion- and immersion-fixed post mortem human brain tissue, termed human Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging / Immunostaining / In situ hybridization-compatible Tissue-hYdrogel (hCLARITY). hCLARITY is optimized for specificity by reducing off-target labeling and yields very sensitive stainings in human brain sections allowing for super-resolution microscopy with unprecedented imaging of pre- and postsynaptic compartments. Moreover, hallmarks of Alzheimer's disease were preserved with hCLARITY, and importantly classical 3,3'-diaminobenzidine (DAB) or Nissl stainings are compatible with this protocol. hCLARITY is very versatile as demonstrated by the use of more than 30 well performing antibodies and allows for de- and subsequent re-staining of the same tissue section, which is important for multi-labeling approaches, e.g., in super-resolution microscopy. CONCLUSIONS Taken together, hCLARITY enables research of the human brain with high sensitivity and down to sub-diffraction resolution. It therefore has enormous potential for the investigation of local morphological changes, e.g., in neurodegenerative diseases.
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Affiliation(s)
- Sarah Woelfle
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- International Graduate School in Molecular Medicine Ulm, IGradU, 89081, Ulm, Germany
| | - Dhruva Deshpande
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Chemical and Systems Biology Department, Stanford School of Medicine, 269 Campus Drive, Stanford, CA, 94305, USA
| | - Simone Feldengut
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Heiko Braak
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Kelly Del Tredici
- Clinical Neuroanatomy Section/Department of Neurology, Center for Biomedical Research, Ulm University, Helmholtzstraße 8/1, 89081, Ulm, Germany
| | - Francesco Roselli
- Department of Neurology, Ulm University, 89081, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE, Ulm Site, 89081, Ulm, Germany
| | - Karl Deisseroth
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, 94305, USA
- Howard Hughes Medical Institute, Stanford, CA, 94305, USA
| | - Jens Michaelis
- Institute of Biophysics, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
| | - Tobias M Boeckers
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen, DZNE, Ulm Site, 89081, Ulm, Germany
| | - Michael Schön
- Institute for Anatomy and Cell Biology, Ulm University, Albert-Einstein-Allee 11, 89081, Ulm, Germany.
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8
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Hindley N, Sanchez Avila A, Henstridge C. Bringing synapses into focus: Recent advances in synaptic imaging and mass-spectrometry for studying synaptopathy. Front Synaptic Neurosci 2023; 15:1130198. [PMID: 37008679 PMCID: PMC10050382 DOI: 10.3389/fnsyn.2023.1130198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 02/28/2023] [Indexed: 03/17/2023] Open
Abstract
Synapses are integral for healthy brain function and are becoming increasingly recognized as key structures in the early stages of brain disease. Understanding the pathological processes driving synaptic dysfunction will unlock new therapeutic opportunities for some of the most devastating diseases of our time. To achieve this we need a solid repertoire of imaging and molecular tools to interrogate synaptic biology at greater resolution. Synapses have historically been examined in small numbers, using highly technical imaging modalities, or in bulk, using crude molecular approaches. However, recent advances in imaging techniques are allowing us to analyze large numbers of synapses, at single-synapse resolution. Furthermore, multiplexing is now achievable with some of these approaches, meaning we can examine multiple proteins at individual synapses in intact tissue. New molecular techniques now allow accurate quantification of proteins from isolated synapses. The development of increasingly sensitive mass-spectrometry equipment means we can now scan the synaptic molecular landscape almost in totality and see how this changes in disease. As we embrace these new technical developments, synapses will be viewed with clearer focus, and the field of synaptopathy will become richer with insightful and high-quality data. Here, we will discuss some of the ways in which synaptic interrogation is being facilitated by methodological advances, focusing on imaging, and mass spectrometry.
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Affiliation(s)
- Nicole Hindley
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- *Correspondence: Nicole Hindley,
| | - Anna Sanchez Avila
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher Henstridge
- Division of Cellular and Systems Medicine, University of Dundee, Dundee, United Kingdom
- Euan Macdonald Centre for Motor Neuron Disease, University of Edinburgh, Edinburgh, United Kingdom
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9
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FUS Alters circRNA Metabolism in Human Motor Neurons Carrying the ALS-Linked P525L Mutation. Int J Mol Sci 2023; 24:ijms24043181. [PMID: 36834591 PMCID: PMC9968238 DOI: 10.3390/ijms24043181] [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: 12/02/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023] Open
Abstract
Deregulation of RNA metabolism has emerged as one of the key events leading to the degeneration of motor neurons (MNs) in Amyotrophic Lateral Sclerosis (ALS) disease. Indeed, mutations on RNA-binding proteins (RBPs) or on proteins involved in aspects of RNA metabolism account for the majority of familiar forms of ALS. In particular, the impact of the ALS-linked mutations of the RBP FUS on many aspects of RNA-related processes has been vastly investigated. FUS plays a pivotal role in splicing regulation and its mutations severely alter the exon composition of transcripts coding for proteins involved in neurogenesis, axon guidance, and synaptic activity. In this study, by using in vitro-derived human MNs, we investigate the effect of the P525L FUS mutation on non-canonical splicing events that leads to the formation of circular RNAs (circRNAs). We observed altered levels of circRNAs in FUSP525L MNs and a preferential binding of the mutant protein to introns flanking downregulated circRNAs and containing inverted Alu repeats. For a subset of circRNAs, FUSP525L also impacts their nuclear/cytoplasmic partitioning, confirming its involvement in different processes of RNA metabolism. Finally, we assess the potential of cytoplasmic circRNAs to act as miRNA sponges, with possible implications in ALS pathogenesis.
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Yokoi S, Ito T, Sahashi K, Nakatochi M, Nakamura R, Tohnai G, Fujioka Y, Ishigaki S, Udagawa T, Izumi Y, Morita M, Kano O, Oda M, Sone T, Okano H, Atsuta N, Katsuno M, Okada Y, Sobue G. The SYNGAP1 3'UTR Variant in ALS Patients Causes Aberrant SYNGAP1 Splicing and Dendritic Spine Loss by Recruiting HNRNPK. J Neurosci 2022; 42:8881-8896. [PMID: 36261283 PMCID: PMC9698725 DOI: 10.1523/jneurosci.0455-22.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 08/28/2022] [Accepted: 10/06/2022] [Indexed: 12/29/2022] Open
Abstract
Fused in sarcoma (FUS) is a pathogenic RNA-binding protein in amyotrophic lateral sclerosis (ALS). We previously reported that FUS stabilizes Synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains spine maturation. To elucidate the pathologic roles of this mechanism in ALS patients, we identified the SYNGAP1 3'UTR variant rs149438267 in seven (four males and three females) out of 807 ALS patients at the FUS binding site from a multicenter cohort in Japan. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, increased isoform α1 levels, and decreased isoform γ levels, which caused dendritic spine loss. Moreover, the SYNGAP1 variant excessively recruited FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK), and antisense oligonucleotides (ASOs) blocking HNRNPK altered aberrant splicing and ameliorated dendritic spine loss. These data suggest that excessive recruitment of RNA-binding proteins, especially HNRNPK, as well as changes in SYNGAP1 isoforms, are crucial for spine formation in motor neurons.SIGNIFICANCE STATEMENT It is not yet known which RNAs cause the pathogenesis of amyotrophic lateral sclerosis (ALS). We previously reported that Fused in sarcoma (FUS), a pathogenic RNA-binding protein in ALS, stabilizes synaptic Ras-GTPase activating protein 1 (Syngap1) mRNA at its 3' untranslated region (UTR) and maintains dendritic spine maturation. To elucidate whether this mechanism is crucial for ALS, we identified the SYNGAP1 3'UTR variant rs149438267 at the FUS binding site. Human-induced pluripotent stem cell (hiPSC)-derived motor neurons with the SYNGAP1 variant showed aberrant splicing, which caused dendritic spine loss along with excessive recruitment of FUS and heterogeneous nuclear ribonucleoprotein K (HNRNPK). Our findings that dendritic spine loss is because of excess recruitment of RNA-binding proteins provide a basis for the future exploration of ALS-related RNA-binding proteins.
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Affiliation(s)
- Satoshi Yokoi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Takuji Ito
- Department of Neurology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan
- Department of Neural iPSC Research, Institute for Medical Science of Aging, Aichi Medical University, Aichi 480-1195, Japan
| | - Kentaro Sahashi
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Masahiro Nakatochi
- Public Health Informatics Unit, Department of Integrated Health Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan
| | - Ryoichi Nakamura
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Neurology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan
| | - Genki Tohnai
- Division of ALS Research, Aichi Medical University, Aichi 480-1195, Japan
| | - Yusuke Fujioka
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Shinsuke Ishigaki
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Research Division of Dementia and Neurodegenerative Disease, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Tsuyoshi Udagawa
- Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya 467-8603, Japan
| | - Yuishin Izumi
- Department of Neurology, Institute of Biomedical Sciences, Tokushima University Graduate School, Tokushima 770-8503, Japan
| | - Mitsuya Morita
- Division of Neurology, Department of Internal Medicine, Jichi Medical University, Shimotsuke 329-0498, Japan
| | - Osamu Kano
- Department of Neurology, Toho University Faculty of Medicine, Tokyo 143-8540, Japan
| | - Masaya Oda
- Department of Neurology, Vihara Hananosato Hospital, Miyoshi 728-0001, Japan
| | - Takefumi Sone
- Department of Physiology, Keio University School of Medicine, Tokyo 160-0016, Japan
| | - Hideyuki Okano
- Department of Physiology, Keio University School of Medicine, Tokyo 160-0016, Japan
| | - Naoki Atsuta
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Department of Neurology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan
| | - Masahisa Katsuno
- Department of Neurology, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
| | - Yohei Okada
- Department of Neurology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan
- Department of Neural iPSC Research, Institute for Medical Science of Aging, Aichi Medical University, Aichi 480-1195, Japan
| | - Gen Sobue
- Research Division of Dementia and Neurodegenerative Disease, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan
- Aichi Medical University, Aichi 480-1195, Japan
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11
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Gelon PA, Dutchak PA, Sephton CF. Synaptic dysfunction in ALS and FTD: anatomical and molecular changes provide insights into mechanisms of disease. Front Mol Neurosci 2022; 15:1000183. [PMID: 36263379 PMCID: PMC9575515 DOI: 10.3389/fnmol.2022.1000183] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 09/01/2022] [Indexed: 11/29/2022] Open
Abstract
Synaptic loss is a pathological feature of all neurodegenerative diseases including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). ALS is a disease of the cortical and spinal motor neurons resulting in fatal paralysis due to denervation of muscles. FTD is a form of dementia that primarily affects brain regions controlling cognition, language and behavior. Once classified as two distinct diseases, ALS and FTD are now considered as part of a common disease spectrum based on overlapping clinical, pathological and genetic evidence. At the cellular level, aggregation of common proteins and overlapping gene susceptibilities are shared in both ALS and FTD. Despite the convergence of these two fields of research, the underlying disease mechanisms remain elusive. However, recent discovers from ALS and FTD patient studies and models of ALS/FTD strongly suggests that synaptic dysfunction is an early event in the disease process and a unifying hallmark of these diseases. This review provides a summary of the reported anatomical and cellular changes that occur in cortical and spinal motor neurons in ALS and FTD tissues and models of disease. We also highlight studies that identify changes in the proteome and transcriptome of ALS and FTD models and provide a conceptual overview of the processes that contribute to synaptic dysfunction in these diseases. Due to space limitations and the vast number of publications in the ALS and FTD fields, many articles have not been discussed in this review. As such, this review focuses on the three most common shared mutations in ALS and FTD, the hexanucleuotide repeat expansion within intron 1 of chromosome 9 open reading frame 72 (C9ORF72), transactive response DNA binding protein 43 (TARDBP or TDP-43) and fused in sarcoma (FUS), with the intention of highlighting common pathways that promote synaptic dysfunction in the ALS-FTD disease spectrum.
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12
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Lum JS, Yerbury JJ. Misfolding at the synapse: A role in amyotrophic lateral sclerosis pathogenesis? Front Mol Neurosci 2022; 15:997661. [PMID: 36157072 PMCID: PMC9500160 DOI: 10.3389/fnmol.2022.997661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Accepted: 08/23/2022] [Indexed: 11/13/2022] Open
Abstract
A growing wave of evidence has placed the concept of protein homeostasis at the center of the pathogenesis of amyotrophic lateral sclerosis (ALS). This is due primarily to the presence of pathological transactive response DNA-binding protein (TDP-43), fused in sarcoma (FUS) or superoxide dismutase-1 (SOD1) inclusions within motor neurons of ALS postmortem tissue. However, the earliest pathological alterations associated with ALS occur to the structure and function of the synapse, prior to motor neuron loss. Recent evidence demonstrates the pathological accumulation of ALS-associated proteins (TDP-43, FUS, C9orf72-associated di-peptide repeats and SOD1) within the axo-synaptic compartment of motor neurons. In this review, we discuss this recent evidence and how axo-synaptic proteome dyshomeostasis may contribute to synaptic dysfunction in ALS.
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Affiliation(s)
- Jeremy S. Lum
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
| | - Justin J. Yerbury
- Illawarra Health and Medical Research Institute, Wollongong, NSW, Australia
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong, Wollongong, NSW, Australia
- *Correspondence: Justin J. Yerbury, ; orcid.org/0000-0003-2528-7039
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Carey JL, Guo L. Liquid-Liquid Phase Separation of TDP-43 and FUS in Physiology and Pathology of Neurodegenerative Diseases. Front Mol Biosci 2022; 9:826719. [PMID: 35187086 PMCID: PMC8847598 DOI: 10.3389/fmolb.2022.826719] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 01/11/2022] [Indexed: 12/12/2022] Open
Abstract
Liquid-liquid phase separation of RNA-binding proteins mediates the formation of numerous membraneless organelles with essential cellular function. However, aberrant phase transition of these proteins leads to the formation of insoluble protein aggregates, which are pathological hallmarks of neurodegenerative diseases including ALS and FTD. TDP-43 and FUS are two such RNA-binding proteins that mislocalize and aggregate in patients of ALS and FTD. They have similar domain structures that provide multivalent interactions driving their phase separation in vitro and in the cellular environment. In this article, we review the factors that mediate and regulate phase separation of TDP-43 and FUS. We also review evidences that connect the phase separation property of TDP-43 and FUS to their functional roles in cells. Aberrant phase transition of TDP-43 and FUS leads to protein aggregation and disrupts their regular cell function. Therefore, restoration of functional protein phase of TDP-43 and FUS could be beneficial for neuronal cells. We discuss possible mechanisms for TDP-43 and FUS aberrant phase transition and aggregation while reviewing the methods that are currently being explored as potential therapeutic strategies to mitigate aberrant phase transition and aggregation of TDP-43 and FUS.
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Sahadevan S, Pérez-Berlanga M, Polymenidou M. Identification of RNA-RBP Interactions in Subcellular Compartments by CLIP-Seq. Methods Mol Biol 2022; 2428:305-323. [PMID: 35171488 DOI: 10.1007/978-1-0716-1975-9_19] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Cross-linking immunoprecipitation and high-throughput sequencing (CLIP-seq) allows the identification of RNA targets bound by a specific RNA-binding protein (RBP) in in vivo and ex vivo experimental models with high specificity. Due to the little RNA yield obtained after cross-linking, immunoprecipitation, polyacrylamide gel electrophoresis, membrane transfer, and RNA extraction, CLIP-seq is usually performed from relatively large amounts of starting material, like cell lysates or tissue homogenates. However, RBP binding of its specific RNA targets depends on its subcellular localization, and a different set of RNAs may be bound by the same RBP within distinct subcellular sites. To uncover these RNA subsets, preparation of CLIP-seq libraries from specific subcellular compartments and comparison to CLIP-seq datasets from total lysates is necessary, yet there are currently no available protocols for this. Here we describe the adaptation of CLIP-seq to identify the specific RNA targets of an RBP (FUS) at a small subcompartment, that is, neuronal synapses, including subcompartment isolation, RBP-RNA complex enrichment, and upscaling steps.
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Affiliation(s)
- Sonu Sahadevan
- Department of Quantitative Biomedicine, University of Zurich, Zurich, Switzerland
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15
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Identification of a novel interaction of FUS and syntaphilin may explain synaptic and mitochondrial abnormalities caused by ALS mutations. Sci Rep 2021; 11:13613. [PMID: 34193962 PMCID: PMC8245466 DOI: 10.1038/s41598-021-93189-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/22/2021] [Indexed: 01/16/2023] Open
Abstract
Aberrantly expressed fused in sarcoma (FUS) is a hallmark of FUS-related amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Wildtype FUS localises to synapses and interacts with mitochondrial proteins while mutations have been shown to cause to pathological changes affecting mitochondria, synapses and the neuromuscular junction (NMJ). This indicates a crucial physiological role for FUS in regulating synaptic and mitochondrial function that is currently poorly understood. In this paper we provide evidence that mislocalised cytoplasmic FUS causes mitochondrial and synaptic changes and that FUS plays a vital role in maintaining neuronal health in vitro and in vivo. Overexpressing mutant FUS altered synaptic numbers and neuronal complexity in both primary neurons and zebrafish models. The degree to which FUS was mislocalised led to differences in the synaptic changes which was mirrored by changes in mitochondrial numbers and transport. Furthermore, we showed that FUS co-localises with the mitochondrial tethering protein Syntaphilin (SNPH), and that mutations in FUS affect this relationship. Finally, we demonstrated mutant FUS led to changes in global protein translation. This localisation between FUS and SNPH could explain the synaptic and mitochondrial defects observed leading to global protein translation defects. Importantly, our results support the ‘gain-of-function’ hypothesis for disease pathogenesis in FUS-related ALS.
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16
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Sahadevan S, Hembach KM, Tantardini E, Pérez-Berlanga M, Hruska-Plochan M, Megat S, Weber J, Schwarz P, Dupuis L, Robinson MD, De Rossi P, Polymenidou M. Synaptic FUS accumulation triggers early misregulation of synaptic RNAs in a mouse model of ALS. Nat Commun 2021; 12:3027. [PMID: 34021139 PMCID: PMC8140117 DOI: 10.1038/s41467-021-23188-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 04/13/2021] [Indexed: 12/12/2022] Open
Abstract
Mutations disrupting the nuclear localization of the RNA-binding protein FUS characterize a subset of amyotrophic lateral sclerosis patients (ALS-FUS). FUS regulates nuclear RNAs, but its role at the synapse is poorly understood. Using super-resolution imaging we determined that the localization of FUS within synapses occurs predominantly near the vesicle reserve pool of presynaptic sites. Using CLIP-seq on synaptoneurosomes, we identified synaptic FUS RNA targets, encoding proteins associated with synapse organization and plasticity. Significant increase of synaptic FUS during early disease in a mouse model of ALS was accompanied by alterations in density and size of GABAergic synapses. mRNAs abnormally accumulated at the synapses of 6-month-old ALS-FUS mice were enriched for FUS targets and correlated with those depicting increased short-term mRNA stability via binding primarily on multiple exonic sites. Our study indicates that synaptic FUS accumulation in early disease leads to synaptic impairment, potentially representing an initial trigger of neurodegeneration.
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Affiliation(s)
- Sonu Sahadevan
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Katharina M Hembach
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
- Department of Molecular Life Sciences and SIB Swiss Institute of Bioinformatics, University of Zurich, Zürich, Switzerland
| | - Elena Tantardini
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | | | | | - Salim Megat
- Inserm, University of Strasbourg, Strasbourg, France
| | - Julien Weber
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Petra Schwarz
- Institute of Neuropathology, University Hospital Zurich, Zürich, Switzerland
| | - Luc Dupuis
- Inserm, University of Strasbourg, Strasbourg, France
| | - Mark D Robinson
- Department of Molecular Life Sciences and SIB Swiss Institute of Bioinformatics, University of Zurich, Zürich, Switzerland
| | - Pierre De Rossi
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
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17
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Scekic-Zahirovic J, Sanjuan-Ruiz I, Kan V, Megat S, De Rossi P, Dieterlé S, Cassel R, Jamet M, Kessler P, Wiesner D, Tzeplaeff L, Demais V, Sahadevan S, Hembach KM, Muller HP, Picchiarelli G, Mishra N, Antonucci S, Dirrig-Grosch S, Kassubek J, Rasche V, Ludolph A, Boutillier AL, Roselli F, Polymenidou M, Lagier-Tourenne C, Liebscher S, Dupuis L. Cytoplasmic FUS triggers early behavioral alterations linked to cortical neuronal hyperactivity and inhibitory synaptic defects. Nat Commun 2021; 12:3028. [PMID: 34021132 PMCID: PMC8140148 DOI: 10.1038/s41467-021-23187-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 04/13/2021] [Indexed: 12/11/2022] Open
Abstract
Gene mutations causing cytoplasmic mislocalization of the RNA-binding protein FUS lead to severe forms of amyotrophic lateral sclerosis (ALS). Cytoplasmic accumulation of FUS is also observed in other diseases, with unknown consequences. Here, we show that cytoplasmic mislocalization of FUS drives behavioral abnormalities in knock-in mice, including locomotor hyperactivity and alterations in social interactions, in the absence of widespread neuronal loss. Mechanistically, we identified a progressive increase in neuronal activity in the frontal cortex of Fus knock-in mice in vivo, associated with altered synaptic gene expression. Synaptic ultrastructural and morphological defects were more pronounced in inhibitory than excitatory synapses and associated with increased synaptosomal levels of FUS and its RNA targets. Thus, cytoplasmic FUS triggers synaptic deficits, which is leading to increased neuronal activity in frontal cortex and causing related behavioral phenotypes. These results indicate that FUS mislocalization may trigger deleterious phenotypes beyond motor neuron impairment in ALS, likely relevant also for other neurodegenerative diseases characterized by FUS mislocalization.
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Affiliation(s)
- Jelena Scekic-Zahirovic
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Inmaculada Sanjuan-Ruiz
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Vanessa Kan
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians-University Munich, Munich, Germany
- BioMedical Center, Medical Faculty, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Salim Megat
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Pierre De Rossi
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Stéphane Dieterlé
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Raphaelle Cassel
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
- Université de Strasbourg, UMR 7364 CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Strasbourg, France
| | - Marguerite Jamet
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Pascal Kessler
- Université de Strasbourg, Inserm, Unité mixte de service du CRBS, UMS 038, Strasbourg, France
| | - Diana Wiesner
- Department of Neurology, Ulm University, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, Germany
| | - Laura Tzeplaeff
- Université de Strasbourg, UMR 7364 CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Strasbourg, France
| | - Valérie Demais
- Plateforme Imagerie In Vitro, CNRS UPS-3156, NeuroPôle, Strasbourg, France
| | - Sonu Sahadevan
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | - Katharina M Hembach
- Department of Quantitative Biomedicine, University of Zurich, Zürich, Switzerland
| | | | - Gina Picchiarelli
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Nibha Mishra
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard University and MIT, Cambridge, MA, USA
| | - Stefano Antonucci
- Department of Neurology, Ulm University, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, Germany
| | - Sylvie Dirrig-Grosch
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France
| | - Jan Kassubek
- Department of Neurology, Ulm University, Ulm, Germany
| | - Volker Rasche
- Ulm University Medical Center, Department of Internal Medicine II, Ulm, Germany
| | - Albert Ludolph
- Department of Neurology, Ulm University, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, Germany
| | - Anne-Laurence Boutillier
- Université de Strasbourg, UMR 7364 CNRS, Laboratoire de Neurosciences Cognitives et Adaptatives (LNCA), Strasbourg, France
| | - Francesco Roselli
- Department of Neurology, Ulm University, Ulm, Germany
- Deutsches Zentrum für Neurodegenerative Erkrankungen (DZNE), Ulm, Germany
| | | | - Clotilde Lagier-Tourenne
- Department of Neurology, The Sean M. Healey and AMG Center for ALS at Mass General, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Broad Institute of Harvard University and MIT, Cambridge, MA, USA
| | - Sabine Liebscher
- Institute of Clinical Neuroimmunology, Klinikum der Universität München, Ludwig-Maximilians-University Munich, Munich, Germany.
- BioMedical Center, Medical Faculty, Ludwig-Maximilians-University Munich, Munich, Germany.
- Munich Cluster for Systems Neurology (SyNergy), Munich, Germany.
| | - Luc Dupuis
- Université de Strasbourg, Inserm, Mécanismes centraux et périphériques de la neurodégénérescence, Strasbourg, France.
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18
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Perrone-Capano C, Volpicelli F, Penna E, Chun JT, Crispino M. Presynaptic protein synthesis and brain plasticity: From physiology to neuropathology. Prog Neurobiol 2021; 202:102051. [PMID: 33845165 DOI: 10.1016/j.pneurobio.2021.102051] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Revised: 03/14/2021] [Accepted: 04/07/2021] [Indexed: 12/12/2022]
Abstract
To form and maintain extremely intricate and functional neural circuitry, mammalian neurons are typically endowed with highly arborized dendrites and a long axon. The synapses that link neurons to neurons or to other cells are numerous and often too remote for the cell body to make and deliver new proteins to the right place in time. Moreover, synapses undergo continuous activity-dependent changes in their number and strength, establishing the basis of neural plasticity. The innate dilemma is then how a highly complex neuron provides new proteins for its cytoplasmic periphery and individual synapses to support synaptic plasticity. Here, we review a growing body of evidence that local protein synthesis in discrete sites of the axon and presynaptic terminals plays crucial roles in synaptic plasticity, and that deregulation of this local translation system is implicated in various pathologies of the nervous system.
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Affiliation(s)
- Carla Perrone-Capano
- Department of Pharmacy, University of Naples Federico II, Naples, Italy; Institute of Genetics and Biophysics "Adriano Buzzati Traverso", CNR, Naples, Italy.
| | | | - Eduardo Penna
- Department of Biology, University of Naples Federico II, Naples, Italy.
| | - Jong Tai Chun
- Department of Biology and Evolution of Marine Organisms, Stazione Zoologica Anton Dohrn, Naples, Italy.
| | - Marianna Crispino
- Department of Biology, University of Naples Federico II, Naples, Italy.
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Klingl YE, Pakravan D, Van Den Bosch L. Opportunities for histone deacetylase inhibition in amyotrophic lateral sclerosis. Br J Pharmacol 2021; 178:1353-1372. [PMID: 32726472 PMCID: PMC9327724 DOI: 10.1111/bph.15217] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. ALS patients suffer from a progressive loss of motor neurons, leading to respiratory failure within 3 to 5 years after diagnosis. Available therapies only slow down the disease progression moderately or extend the lifespan by a few months. Epigenetic hallmarks have been linked to the disease, creating an avenue for potential therapeutic approaches. Interference with one class of epigenetic enzymes, histone deacetylases, has been shown to affect neurodegeneration in many preclinical models. Consequently, it is crucial to improve our understanding about histone deacetylases and their inhibitors in (pre)clinical models of ALS. We conclude that selective inhibitors with high tolerability and safety and sufficient blood-brain barrier permeability will be needed to interfere with both epigenetic and non-epigenetic targets of these enzymes. LINKED ARTICLES: This article is part of a themed issue on Neurochemistry in Japan. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v178.6/issuetoc.
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Affiliation(s)
- Yvonne E. Klingl
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI)KU Leuven‐University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
| | - Donya Pakravan
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI)KU Leuven‐University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
| | - Ludo Van Den Bosch
- Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI)KU Leuven‐University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
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20
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Markert SM, Skoruppa M, Yu B, Mulcahy B, Zhen M, Gao S, Sendtner M, Stigloher C. Overexpression of an ALS-associated FUS mutation in C. elegans disrupts NMJ morphology and leads to defective neuromuscular transmission. Biol Open 2020; 9:bio055129. [PMID: 33148607 PMCID: PMC7746668 DOI: 10.1242/bio.055129] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 10/27/2020] [Indexed: 12/26/2022] Open
Abstract
The amyotrophic lateral sclerosis (ALS) neurodegenerative disorder has been associated with multiple genetic lesions, including mutations in the gene for fused in sarcoma (FUS), a nuclear-localized RNA/DNA-binding protein. Neuronal expression of the pathological form of FUS proteins in Caenorhabditis elegans results in mislocalization and aggregation of FUS in the cytoplasm, and leads to impairment of motility. However, the mechanisms by which the mutant FUS disrupts neuronal health and function remain unclear. Here we investigated the impact of ALS-associated FUS on motor neuron health using correlative light and electron microscopy, electron tomography, and electrophysiology. We show that ectopic expression of wild-type or ALS-associated human FUS impairs synaptic vesicle docking at neuromuscular junctions. ALS-associated FUS led to the emergence of a population of large, electron-dense, and filament-filled endosomes. Electrophysiological recording revealed reduced transmission from motor neurons to muscles. Together, these results suggest a pathological effect of ALS-causing FUS at synaptic structure and function organization.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Sebastian M Markert
- University of Würzburg, Biocenter, Imaging Core Facility, Am Hubland, Würzburg 97074, Germany
| | - Michael Skoruppa
- University Hospital Würzburg, Institute of Clinical Neurobiology, Versbacherstraße 5, 97080 Würzburg, Germany
| | - Bin Yu
- Huazhong University of Science and Technology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Wuhan 430074, China
| | - Ben Mulcahy
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
| | - Mei Zhen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, Ontario M5G 1X5, Canada
- University of Toronto, Department of Molecular Genetics, Physiology and Institute of Medical Science, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Shangbang Gao
- Huazhong University of Science and Technology, Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Wuhan 430074, China
| | - Michael Sendtner
- University Hospital Würzburg, Institute of Clinical Neurobiology, Versbacherstraße 5, 97080 Würzburg, Germany
| | - Christian Stigloher
- University of Würzburg, Biocenter, Imaging Core Facility, Am Hubland, Würzburg 97074, Germany
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21
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Abstract
RNA-binding proteins are a critical group of multifunctional proteins that precisely regulate all aspects of gene expression, from alternative splicing to mRNA trafficking, stability, and translation. Converging evidence highlights aberrant RNA metabolism as a common pathogenic mechanism in several neurodevelopmental and neurodegenerative diseases. However, dysregulation of disease-linked RNA-binding proteins results in widespread, often tissue-specific and/or pleiotropic effects on the transcriptome, making it challenging to determine the underlying cellular and molecular mechanisms that contribute to disease pathogenesis. Understanding how splicing misregulation as well as alterations of mRNA stability and localization impact the activity and function of neuronal proteins is fundamental to addressing neurodevelopmental defects and synaptic dysfunction in disease. Here we highlight recent exciting studies that use high-throughput transcriptomic analysis and advanced genetic, cell biological, and imaging approaches to dissect the role of disease-linked RNA-binding proteins on different RNA processing steps. We focus specifically on efforts to elucidate the functional consequences of aberrant RNA processing on neuronal morphology, synaptic activity and plasticity in development and disease. We also consider new areas of investigation that will elucidate the molecular mechanisms RNA-binding proteins use to achieve spatiotemporal control of gene expression for neuronal homeostasis and plasticity.
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Affiliation(s)
- Shavanie Prashad
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA
| | - Pallavi P Gopal
- Department of Pathology, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Experimental Pathology Graduate Group, Yale University School of Medicine, Yale University, New Haven, CT, USA.,Yale Center for RNA Science and Medicine, Yale University School of Medicine, Yale University, New Haven, CT, USA
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22
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Vasques JF, Mendez-Otero R, Gubert F. Modeling ALS using iPSCs: is it possible to reproduce the phenotypic variations observed in patients in vitro? Regen Med 2020; 15:1919-1933. [PMID: 32795164 DOI: 10.2217/rme-2020-0067] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal disease that leads to progressive degeneration of motoneurons. Mutations in the C9ORF72, SOD1, TARDBP and FUS genes, among others, have been associated with ALS. Although motoneuron degeneration is the common outcome of ALS, different pathological mechanisms seem to be involved in this process, depending on the genotypic background of the patient. The advent of induced pluripotent stem cell (iPSC) technology enabled the development of patient-specific cell lines, from which it is possible to generate different cell types and search for phenotypic alterations. In this review, we summarize the pathophysiological markers detected in cells differentiated from iPSCs of ALS patients. In a translational perspective, iPSCs from ALS patients could be useful for drug screening, through stratifying patients according to their genetic background.
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Affiliation(s)
- Juliana Ferreira Vasques
- Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Medicina Regenerativa
| | - Rosalia Mendez-Otero
- Instituto de Biofísica Carlos Chagas Filho, UFRJ, Rio de Janeiro, Brazil.,Instituto Nacional de Ciência e Tecnologia em Medicina Regenerativa
| | - Fernanda Gubert
- Instituto Nacional de Ciência e Tecnologia em Medicina Regenerativa.,Instituto de Ciências Biomédicas, UFRJ, Rio de Janeiro, Brazil
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23
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Xue YC, Ng CS, Xiang P, Liu H, Zhang K, Mohamud Y, Luo H. Dysregulation of RNA-Binding Proteins in Amyotrophic Lateral Sclerosis. Front Mol Neurosci 2020; 13:78. [PMID: 32547363 PMCID: PMC7273501 DOI: 10.3389/fnmol.2020.00078] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 04/22/2020] [Indexed: 12/11/2022] Open
Abstract
Genetic analyses of patients with amyotrophic lateral sclerosis (ALS) have revealed a strong association between mutations in genes encoding many RNA-binding proteins (RBPs), including TARDBP, FUS, hnRNPA1, hnRNPA2B1, MATR3, ATXN2, TAF15, TIA-1, and EWSR1, and disease onset/progression. RBPs are a group of evolutionally conserved proteins that participate in multiple steps of RNA metabolism, including splicing, polyadenylation, mRNA stability, localization, and translation. Dysregulation of RBPs, as a consequence of gene mutations, impaired nucleocytoplasmic trafficking, posttranslational modification (PTM), aggregation, and sequestration by abnormal RNA foci, has been shown to be involved in neurodegeneration and the development of ALS. While the exact mechanism by which dysregulated RBPs contribute to ALS remains elusive, emerging evidence supports the notion that both a loss of function and/or a gain of toxic function of these ALS-linked RBPs play a significant role in disease pathogenesis through facilitating abnormal protein interaction, causing aberrant RNA metabolism, and by disturbing ribonucleoprotein granule dynamics and phase transition. In this review article, we summarize the current knowledge on the molecular mechanism by which RBPs are dysregulated and the influence of defective RBPs on cellular homeostasis during the development of ALS. The strategies of ongoing clinical trials targeting RBPs and/or relevant processes are also discussed in the present review.
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Affiliation(s)
- Yuan Chao Xue
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Chen Seng Ng
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Pinhao Xiang
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Huitao Liu
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Experimental Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Kevin Zhang
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Yasir Mohamud
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Honglin Luo
- Centre for Heart and Lung Innovation, St. Paul's Hospital, Vancouver, BC, Canada.,Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
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24
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Sasaki Y. Local Translation in Growth Cones and Presynapses, Two Axonal Compartments for Local Neuronal Functions. Biomolecules 2020; 10:biom10050668. [PMID: 32344905 PMCID: PMC7277458 DOI: 10.3390/biom10050668] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 04/08/2020] [Accepted: 04/21/2020] [Indexed: 01/02/2023] Open
Abstract
During neural development, growth cones, very motile compartments of tips of axons, lead axonal extension to the correct targets. Subsequently, presynapses, another axonal compartment with vigorous trafficking of synaptic vesicles, emerge to form functional synapses with postsynapses. In response to extracellular stimuli, the immediate supply of proteins by local translation within these two axonal compartments far from cell bodies confers high motility of growth cones and active vesicle trafficking in presynapses. Although local translation in growth cones and presynapses occurs at a very low level compared with cell bodies and even dendrites, recent progress in omics and visualization techniques with subcellular fractionation of these compartments has revealed the actual situation of local translation within these two axonal compartments. Here, the increasing evidence for local protein synthesis in growth cones and presynapses for axonal and synaptic functions has been reviewed. Furthermore, the mechanisms regulating local translation in these two compartments and pathophysiological conditions caused by dysregulated local translation are highlighted.
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Affiliation(s)
- Yukio Sasaki
- Functional Structure Biology Laboratory, Department of Medical Life Science, Yokohama City University Graduate School of Medical Life Science, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan
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25
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Imperatore JA, McAninch DS, Valdez-Sinon AN, Bassell GJ, Mihailescu MR. FUS Recognizes G Quadruplex Structures Within Neuronal mRNAs. Front Mol Biosci 2020; 7:6. [PMID: 32118033 PMCID: PMC7018707 DOI: 10.3389/fmolb.2020.00006] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 01/10/2020] [Indexed: 12/14/2022] Open
Abstract
Fused in sarcoma (FUS), identified as the heterogeneous nuclear ribonuclear protein P2, is expressed in neuronal and non-neuronal tissue, and among other functions, has been implicated in messenger RNA (mRNA) transport and possibly local translation regulation. Although FUS is mainly localized to the nucleus, in the neurons FUS has also been shown to localize to the post-synaptic density, as well as to the pre-synapse. Additionally, the FUS deletion in cultured hippocampal cells results in abnormal spine and dendrite morphology. Thus, FUS may play a role in synaptic function regulation, mRNA localization, and local translation. Many dendritic mRNAs have been shown to form G quadruplex structures in their 3'-untranslated region (3'-UTR). Since FUS contains three arginine-glycine-glycine (RGG) boxes, an RNA binding domain shown to bind with high affinity and specificity to RNA G quadruplex structures, in this study we hypothesized that FUS recognizes these structural elements in its neuronal mRNA targets. Two neuronal mRNAs found in the pre- and post-synapse are the post-synaptic density protein 95 (PSD-95) and Shank1 mRNAs, which encode for proteins involved in synaptic plasticity, maintenance, and function. These mRNAs have been shown to form 3'-UTR G quadruplex structures and were also enriched in FUS hydrogels. In this study, we used native gel electrophoresis and steady-state fluorescence spectroscopy to demonstrate specific nanomolar binding of the FUS C-terminal RGG box and of full-length FUS to the RNA G quadruplex structures formed in the 3'-UTR of PSD-95 and Shank1a mRNAs. These results point toward a novel mechanism by which FUS targets neuronal mRNA and given that these PSD-95 and Shank1 3'-UTR G quadruplex structures are also targeted by the fragile X mental retardation protein (FMRP), they raise the possibility that FUS and FMRP might work together to regulate the translation of these neuronal mRNA targets.
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Affiliation(s)
- Joshua A. Imperatore
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, United States
| | - Damian S. McAninch
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, United States
| | | | - Gary J. Bassell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Mihaela Rita Mihailescu
- Department of Chemistry and Biochemistry, Duquesne University, Pittsburgh, PA, United States
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