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Sellier C, Corcia P, Vourc'h P, Dupuis L. C9ORF72 hexanucleotide repeat expansion: From ALS and FTD to a broader pathogenic role? Rev Neurol (Paris) 2024; 180:417-428. [PMID: 38609750 DOI: 10.1016/j.neurol.2024.03.008] [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: 03/20/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024]
Abstract
The major gene underlying monogenic forms of amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD) is C9ORF72. The causative mutation in C9ORF72 is an abnormal hexanucleotide (G4C2) repeat expansion (HRE) located in the first intron of the gene. The aim of this review is to propose a comprehensive update on recent developments on clinical, biological and therapeutics aspects related to C9ORF72 in order to highlight the current understanding of genotype-phenotype correlations, and also on biological machinery leading to neuronal death. We will particularly focus on the broad phenotypic presentation of C9ORF72-related diseases, that goes well beyond the classical phenotypes observed in ALS and FTD patients. Last, we will comment the possible therapeutical hopes for patients carrying a C9ORF72 HRE.
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Affiliation(s)
- C Sellier
- Centre de recherches en biomédecine de Strasbourg, UMR-S1329, Inserm, université de Strasbourg, Strasbourg, France
| | - P Corcia
- UMR 1253 iBrain, Inserm, université de Tours, Tours, France; Centre constitutif de coordination SLA, CHU de Bretonneau, 2, boulevard Tonnelle, 37044 Tours cedex 1, France
| | - P Vourc'h
- UMR 1253 iBrain, Inserm, université de Tours, Tours, France; Service de biochimie et biologie moléculaire, CHU de Tours, Tours, France
| | - L Dupuis
- Centre de recherches en biomédecine de Strasbourg, UMR-S1329, Inserm, université de Strasbourg, Strasbourg, France.
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2
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Martin EJ, Santacruz C, Mitevska A, Jones IE, Krishnan G, Gao FB, Finan JD, Kiskinis E. Traumatic injury causes selective degeneration and TDP-43 mislocalization in human iPSC-derived C9orf72-associated ALS/FTD motor neurons. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.21.586073. [PMID: 38585915 PMCID: PMC10996466 DOI: 10.1101/2024.03.21.586073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/09/2024]
Abstract
A hexanucleotide repeat expansion (HRE) in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). However, patients with the HRE exhibit a wide disparity in clinical presentation and age of symptom onset suggesting an interplay between genetic background and environmental stressors. Neurotrauma as a result of traumatic brain or spinal cord injury has been shown to increase the risk of ALS/FTD in epidemiological studies. Here, we combine patient-specific induced pluripotent stem cells (iPSCs) with a custom-built device to deliver biofidelic stretch trauma to C9orf72 patient and isogenic control motor neurons (MNs) in vitro. We find that mutant but not control MNs exhibit selective degeneration after a single incident of severe trauma, which can be partially rescued by pretreatment with a C9orf72 antisense oligonucleotide. A single incident of mild trauma does not cause degeneration but leads to cytoplasmic accumulation of TDP-43 in C9orf72 MNs. This mislocalization, which only occurs briefly in isogenic controls, is eventually restored in C9orf72 MNs after 6 days. Lastly, repeated mild trauma ablates the ability of patient MNs to recover. These findings highlight alterations in TDP-43 dynamics in C9orf72 ALS/FTD patient MNs following traumatic injury and demonstrate that neurotrauma compounds neuropathology in C9orf72 ALS/FTD. More broadly, our work establishes an in vitro platform that can be used to interrogate the mechanistic interactions between ALS/FTD and neurotrauma.
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Affiliation(s)
- Eric J. Martin
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Citlally Santacruz
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Angela Mitevska
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Ian E. Jones
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Gopinath Krishnan
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- RNA Therapeutics Institute, University of Massachusetts Medical School, Worcester, MA 01605, USA
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John D. Finan
- Department of Mechanical and Industrial Engineering, University of Illinois at Chicago, Chicago, IL, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, USA
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL, 60611, USA
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3
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Smeele PH, Cesare G, Vaccari T. ALS' Perfect Storm: C9orf72-Associated Toxic Dipeptide Repeats as Potential Multipotent Disruptors of Protein Homeostasis. Cells 2024; 13:178. [PMID: 38247869 PMCID: PMC10813877 DOI: 10.3390/cells13020178] [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: 12/13/2023] [Revised: 01/10/2024] [Accepted: 01/12/2024] [Indexed: 01/23/2024] Open
Abstract
Protein homeostasis is essential for neuron longevity, requiring a balanced regulation between protein synthesis and degradation. The clearance of misfolded and aggregated proteins, mediated by autophagy and the ubiquitin-proteasome systems, maintains protein homeostasis in neurons, which are post-mitotic and thus cannot use cell division to diminish the burden of misfolded proteins. When protein clearance pathways are overwhelmed or otherwise disrupted, the accumulation of misfolded or aggregated proteins can lead to the activation of ER stress and the formation of stress granules, which predominantly attempt to restore the homeostasis by suppressing global protein translation. Alterations in these processes have been widely reported among studies investigating the toxic function of dipeptide repeats (DPRs) produced by G4C2 expansion in the C9orf72 gene of patients with amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). In this review, we outline the modalities of DPR-induced disruptions in protein homeostasis observed in a wide range of models of C9orf72-linked ALS/FTD. We also discuss the relative importance of each DPR for toxicity, possible synergies between DPRs, and discuss the possible functional relevance of DPR aggregation to disease pathogenesis. Finally, we highlight the interdependencies of the observed effects and reflect on the importance of feedback and feedforward mechanisms in their contribution to disease progression. A better understanding of DPR-associated disease pathogenesis discussed in this review might shed light on disease vulnerabilities that may be amenable with therapeutic interventions.
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Affiliation(s)
| | | | - Thomas Vaccari
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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4
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Ortega JA, Sasselli IR, Boccitto M, Fleming AC, Fortuna TR, Li Y, Sato K, Clemons TD, Mckenna ED, Nguyen TP, Anderson EN, Asin J, Ichida JK, Pandey UB, Wolin SL, Stupp SI, Kiskinis E. CLIP-Seq analysis enables the design of protective ribosomal RNA bait oligonucleotides against C9ORF72 ALS/FTD poly-GR pathophysiology. SCIENCE ADVANCES 2023; 9:eadf7997. [PMID: 37948524 PMCID: PMC10637751 DOI: 10.1126/sciadv.adf7997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2022] [Accepted: 10/11/2023] [Indexed: 11/12/2023]
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia patients with a hexanucleotide repeat expansion in C9ORF72 (C9-HRE) accumulate poly-GR and poly-PR aggregates. The pathogenicity of these arginine-rich dipeptide repeats (R-DPRs) is thought to be driven by their propensity to bind low-complexity domains of multivalent proteins. However, the ability of R-DPRs to bind native RNA and the significance of this interaction remain unclear. Here, we used computational and experimental approaches to characterize the physicochemical properties of R-DPRs and their interaction with RNA. We find that poly-GR predominantly binds ribosomal RNA (rRNA) in cells and exhibits an interaction that is predicted to be energetically stronger than that for associated ribosomal proteins. Critically, modified rRNA "bait" oligonucleotides restore poly-GR-associated ribosomal deficits and ameliorate poly-GR toxicity in patient neurons and Drosophila models. Our work strengthens the hypothesis that ribosomal function is impaired by R-DPRs, highlights a role for direct rRNA binding in mediating ribosomal dysfunction, and presents a strategy for protecting against C9-HRE pathophysiological mechanisms.
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Affiliation(s)
- Juan A. Ortega
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, Barcelona 08907, Spain
| | - Ivan R. Sasselli
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Center for Cooperative Research in Biomaterials (CIC biomaGUNE), Basque Research and Technology Alliance (BRTA), Donostia-San Sebastián 20014, Spain
- Centro de Fisica de Materiales (CFM), CSIC-UPV/EHU, 20018 San Sebastián, Spain
| | - Marco Boccitto
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Andrew C. Fleming
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Tyler R. Fortuna
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Yichen Li
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Kohei Sato
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Tristan D. Clemons
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
| | - Elizabeth D. Mckenna
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Thao P. Nguyen
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Eric N. Anderson
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Jesus Asin
- Department of Statistical Methods, School of Engineering, University of Zaragoza, Zaragoza 50018, Spain
| | - Justin K. Ichida
- Department of Stem Cell Biology and Regenerative Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - Udai B. Pandey
- Department of Pediatrics, Children’s Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, USA
| | - Sandra L. Wolin
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Samuel I. Stupp
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Department of Biomedical Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Materials Science and Engineering, Northwestern University, Evanston, IL 60208, USA
- Department of Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Evangelos Kiskinis
- The Ken & Ruth Davee Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA
- Simpson Querrey Institute for BioNanotechnology, Northwestern University, Chicago, IL 60611, USA
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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5
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Cristi AC, Rapuri S, Coyne AN. Nuclear pore complex and nucleocytoplasmic transport disruption in neurodegeneration. FEBS Lett 2023; 597:2546-2566. [PMID: 37657945 PMCID: PMC10612469 DOI: 10.1002/1873-3468.14729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 07/29/2023] [Accepted: 08/24/2023] [Indexed: 09/03/2023]
Abstract
Nuclear pore complexes (NPCs) play a critical role in maintaining the equilibrium between the nucleus and cytoplasm, enabling bidirectional transport across the nuclear envelope, and are essential for proper nuclear organization and gene regulation. Perturbations in the regulatory mechanisms governing NPCs and nuclear envelope homeostasis have been implicated in the pathogenesis of several neurodegenerative diseases. The ESCRT-III pathway emerges as a critical player in the surveillance and preservation of well-assembled, functional NPCs, as well as nuclear envelope sealing. Recent studies have provided insights into the involvement of nuclear ESCRT-III in the selective reduction of specific nucleoporins associated with neurodegenerative pathologies. Thus, maintaining quality control of the nuclear envelope and NPCs represents a pivotal element in the pathological cascade leading to neurodegenerative diseases. This review describes the constituents of the nuclear-cytoplasmic transport machinery, encompassing the nuclear envelope, NPC, and ESCRT proteins, and how their structural and functional alterations contribute to the development of neurodegenerative diseases.
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Affiliation(s)
- América Chandía Cristi
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
| | - Sampath Rapuri
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
| | - Alyssa N Coyne
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore MD 21205, USA
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6
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De Marchi F, Franjkic T, Schito P, Russo T, Nimac J, Chami AA, Mele A, Vidatic L, Kriz J, Julien JP, Apic G, Russell RB, Rogelj B, Cannon JR, Baralle M, Agosta F, Hecimovic S, Mazzini L, Buratti E, Munitic I. Emerging Trends in the Field of Inflammation and Proteinopathy in ALS/FTD Spectrum Disorder. Biomedicines 2023; 11:1599. [PMID: 37371694 PMCID: PMC10295684 DOI: 10.3390/biomedicines11061599] [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: 04/28/2023] [Revised: 05/27/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Proteinopathy and neuroinflammation are two main hallmarks of neurodegenerative diseases. They also represent rare common events in an exceptionally broad landscape of genetic, environmental, neuropathologic, and clinical heterogeneity present in patients. Here, we aim to recount the emerging trends in amyotrophic lateral sclerosis (ALS) and frontotemporal degeneration (FTD) spectrum disorder. Our review will predominantly focus on neuroinflammation and systemic immune imbalance in ALS and FTD, which have recently been highlighted as novel therapeutic targets. A common mechanism of most ALS and ~50% of FTD patients is dysregulation of TAR DNA-binding protein 43 (TDP-43), an RNA/DNA-binding protein, which becomes depleted from the nucleus and forms cytoplasmic aggregates in neurons and glia. This, in turn, via both gain and loss of function events, alters a variety of TDP-43-mediated cellular events. Experimental attempts to target TDP-43 aggregates or manipulate crosstalk in the context of inflammation will be discussed. Targeting inflammation, and the immune system in general, is of particular interest because of the high plasticity of immune cells compared to neurons.
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Affiliation(s)
- Fabiola De Marchi
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Toni Franjkic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
- Metisox, Cambridge CB24 9NL, UK;
| | - Paride Schito
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Tommaso Russo
- Department of Neurology & Neuropathology Unit, Institute of Experimental Neurology (INSPE), Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy; (P.S.); (T.R.)
| | - Jerneja Nimac
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Graduate School of Biomedicine, Faculty of Medicine, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Anna A. Chami
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Angelica Mele
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Lea Vidatic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Jasna Kriz
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | - Jean-Pierre Julien
- CERVO Research Centre, Laval University, Quebec City, QC G1J 2G3, Canada; (A.A.C.); (J.K.); (J.-P.J.)
| | | | | | - Boris Rogelj
- Department of Biotechnology, Jozef Stefan Institute, SI-1000 Ljubljana, Slovenia; (J.N.); (B.R.)
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Jason R. Cannon
- School of Health Sciences, Purdue University, West Lafayette, IN 47907, USA;
- Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | | | - Federica Agosta
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, IRCCS San Raffaele Scientific Institute, 20132 Milan, Italy;
| | - Silva Hecimovic
- Laboratory for Neurodegenerative Disease Research, Division of Molecular Medicine, Ruder Boskovic Institute, 10000 Zagreb, Croatia; (L.V.); (S.H.)
| | - Letizia Mazzini
- Department of Neurology and ALS Centre, University of Piemonte Orientale, Maggiore Della Carità Hospital, Corso Mazzini 18, 28100 Novara, Italy; (F.D.M.); (A.M.)
| | - Emanuele Buratti
- International Centre for Genetic Engineering and Biotechnology (ICGEB), Padriciano 99, 34149 Trieste, Italy
| | - Ivana Munitic
- Laboratory for Molecular Immunology, Department of Biotechnology, University of Rijeka, R. Matejcic 2, 51000 Rijeka, Croatia;
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7
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Wilson DM, Cookson MR, Van Den Bosch L, Zetterberg H, Holtzman DM, Dewachter I. Hallmarks of neurodegenerative diseases. Cell 2023; 186:693-714. [PMID: 36803602 DOI: 10.1016/j.cell.2022.12.032] [Citation(s) in RCA: 218] [Impact Index Per Article: 218.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 11/23/2022] [Accepted: 12/19/2022] [Indexed: 02/18/2023]
Abstract
Decades of research have identified genetic factors and biochemical pathways involved in neurodegenerative diseases (NDDs). We present evidence for the following eight hallmarks of NDD: pathological protein aggregation, synaptic and neuronal network dysfunction, aberrant proteostasis, cytoskeletal abnormalities, altered energy homeostasis, DNA and RNA defects, inflammation, and neuronal cell death. We describe the hallmarks, their biomarkers, and their interactions as a framework to study NDDs using a holistic approach. The framework can serve as a basis for defining pathogenic mechanisms, categorizing different NDDs based on their primary hallmarks, stratifying patients within a specific NDD, and designing multi-targeted, personalized therapies to effectively halt NDDs.
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Affiliation(s)
- David M Wilson
- Hasselt University, Biomedical Research Institute, BIOMED, 3500 Hasselt, Belgium.
| | - Mark R Cookson
- Laboratory of Neurogenetics, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ludo Van Den Bosch
- KU Leuven, University of Leuven, Department of Neurosciences, Experimental Neurology and Leuven Brain Institute (LBI), 3000 Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, 3000 Leuven, Belgium
| | - Henrik Zetterberg
- Department of Psychiatry and Neurochemistry, Institute of Neuroscience and Physiology, the Sahlgrenska Academy at the University of Gothenburg, Mölndal, Sweden; Clinical Neurochemistry Laboratory, Sahlgrenska University Hospital, Mölndal, Sweden; Department of Neurodegenerative Disease, UCL Institute of Neurology, Queen Square, London, UK; UK Dementia Research Institute at UCL, London, UK; Hong Kong Center for Neurodegenerative Diseases, Clear Water Bay, Hong Kong, China; UW Department of Medicine, School of Medicine and Public Health, Madison, WI, USA
| | - David M Holtzman
- Department of Neurology, Hope Center for Neurological Disorders, Knight Alzheimer's Disease Research Center, Washington University in St. Louis, St. Louis, MO, USA
| | - Ilse Dewachter
- Hasselt University, Biomedical Research Institute, BIOMED, 3500 Hasselt, Belgium.
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8
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Lopez-Herdoiza MB, Bauché S, Wilmet B, Le Duigou C, Roussel D, Frah M, Béal J, Devely G, Boluda S, Frick P, Bouteiller D, Dussaud S, Guillabert P, Dalle C, Dumont M, Camuzat A, Saracino D, Barbier M, Bruneteau G, Ravassard P, Neumann M, Nicole S, Le Ber I, Brice A, Latouche M. C9ORF72 knockdown triggers FTD-like symptoms and cell pathology in mice. Front Cell Neurosci 2023; 17:1155929. [PMID: 37138765 PMCID: PMC10149765 DOI: 10.3389/fncel.2023.1155929] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 03/27/2023] [Indexed: 05/05/2023] Open
Abstract
The GGGGCC intronic repeat expansion within C9ORF72 is the most common genetic cause of ALS and FTD. This mutation results in toxic gain of function through accumulation of expanded RNA foci and aggregation of abnormally translated dipeptide repeat proteins, as well as loss of function due to impaired transcription of C9ORF72. A number of in vivo and in vitro models of gain and loss of function effects have suggested that both mechanisms synergize to cause the disease. However, the contribution of the loss of function mechanism remains poorly understood. We have generated C9ORF72 knockdown mice to mimic C9-FTD/ALS patients haploinsufficiency and investigate the role of this loss of function in the pathogenesis. We found that decreasing C9ORF72 leads to anomalies of the autophagy/lysosomal pathway, cytoplasmic accumulation of TDP-43 and decreased synaptic density in the cortex. Knockdown mice also developed FTD-like behavioral deficits and mild motor phenotypes at a later stage. These findings show that C9ORF72 partial loss of function contributes to the damaging events leading to C9-FTD/ALS.
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Affiliation(s)
| | - Stephanie Bauché
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Baptiste Wilmet
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Caroline Le Duigou
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Delphine Roussel
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Magali Frah
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Jonas Béal
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Gabin Devely
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Susana Boluda
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Petra Frick
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | | | - Sébastien Dussaud
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Pierre Guillabert
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Carine Dalle
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Magali Dumont
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Agnes Camuzat
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Dario Saracino
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Mathieu Barbier
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Gaelle Bruneteau
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | | | - Manuela Neumann
- German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
- Department of Neuropathology, Tübingen University Hospital, Tübingen, Germany
| | - Sophie Nicole
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Isabelle Le Ber
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Alexis Brice
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
| | - Morwena Latouche
- Institut du Cerveau–Paris Brain Institute–ICM, Inserm, CNRS, Paris, France
- EPHE, Neurogenetics Team, PSL Research University, Paris, France
- *Correspondence: Morwena Latouche,
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9
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Dubey SK, Maulding K, Sung H, Lloyd TE. Nucleoporins are degraded via upregulation of ESCRT-III/Vps4 complex in Drosophila models of C9-ALS/FTD. Cell Rep 2022; 40:111379. [PMID: 36130523 PMCID: PMC10099287 DOI: 10.1016/j.celrep.2022.111379] [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: 08/03/2021] [Revised: 03/22/2022] [Accepted: 08/28/2022] [Indexed: 11/03/2022] Open
Abstract
Disruption of the nuclear pore complex (NPC) and nucleocytoplasmic transport (NCT) have been implicated in the pathogenesis of neurodegenerative diseases. A GGGGCC hexanucleotide repeat expansion (HRE) in an intron of the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia, but the mechanism by which the HRE disrupts NCT is incompletely understood. We find that expression of GGGGCC repeats in Drosophila neurons induces proteasome-mediated degradation of select nucleoporins of the NPC. This process requires the Vps4 ATPase and the endosomal-sorting complex required for transport complex-III (ESCRT-III), as knockdown of ESCRT-III/Vps4 genes rescues nucleoporin levels, normalizes NCT, and suppresses GGGGCC-mediated neurodegeneration. GGGGCC expression upregulates nuclear ESCRT-III/Vps4 expression, and expansion microscopy demonstrates that the nucleoporins are translocated into the cytoplasm before undergoing proteasome-mediated degradation. These findings demonstrate a mechanism for nucleoporin degradation and NPC dysfunction in neurodegenerative disease.
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Affiliation(s)
- Sandeep Kumar Dubey
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kirstin Maulding
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular and Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Hyun Sung
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thomas E Lloyd
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Cellular and Molecular Medicine Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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10
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Fourier A, Quadrio I. Proteinopathies associated to repeat expansion disorders. J Neural Transm (Vienna) 2022; 129:173-185. [DOI: 10.1007/s00702-021-02454-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/13/2021] [Indexed: 12/11/2022]
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11
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Arginine-rich dipeptide-repeat proteins as phase disruptors in C9-ALS/FTD. Emerg Top Life Sci 2021; 4:293-305. [PMID: 32639008 DOI: 10.1042/etls20190167] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/15/2020] [Accepted: 06/17/2020] [Indexed: 12/11/2022]
Abstract
A hexanucleotide repeat expansion GGGGCC (G4C2) within chromosome 9 open reading frame 72 (C9orf72) is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9-ALS/FTD). This seminal realization has rapidly focused our attention to the non-canonical translation (RAN translation) of the repeat expansion, which yields dipeptide-repeat protein products (DPRs). The mechanisms by which DPRs might contribute to C9-ALS/FTD are widely studied. Arginine-rich DPRs (R-DPRs) are the most toxic of the five different DPRs produced in neurons, but how do R-DPRs promote C9-ALS/FTD pathogenesis? Proteomic analyses have uncovered potential pathways to explore. For example, the vast majority of the R-DPR interactome is comprised of disease-linked RNA-binding proteins (RBPs) with low-complexity domains (LCDs), strongly suggesting a link between R-DPRs and aberrations in liquid-liquid phase separation (LLPS). In this review, we showcase several potential mechanisms by which R-DPRs disrupt various phase-separated compartments to elicit deleterious neurodegeneration. We also discuss potential therapeutic strategies to counter R-DPR toxicity in C9-ALS/FTD.
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12
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Blood-spinal cord barrier leakage is independent of motor neuron pathology in ALS. Acta Neuropathol Commun 2021; 9:144. [PMID: 34446086 PMCID: PMC8393479 DOI: 10.1186/s40478-021-01244-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/11/2021] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease involving progressive degeneration of upper and lower motor neurons. The pattern of lower motor neuron loss along the spinal cord follows the pattern of deposition of phosphorylated TDP-43 aggregates. The blood-spinal cord barrier (BSCB) restricts entry into the spinal cord parenchyma of blood components that can promote motor neuron degeneration, but in ALS there is evidence for barrier breakdown. Here we sought to quantify BSCB breakdown along the spinal cord axis, to determine whether BSCB breakdown displays the same patterning as motor neuron loss and TDP-43 proteinopathy. Cerebrospinal fluid hemoglobin was measured in living ALS patients (n = 87 control, n = 236 ALS) as a potential biomarker of BSCB and blood–brain barrier leakage. Cervical, thoracic, and lumbar post-mortem spinal cord tissue (n = 5 control, n = 13 ALS) were then immunolabelled and semi-automated imaging and analysis performed to quantify hemoglobin leakage, lower motor neuron loss, and phosphorylated TDP-43 inclusion load. Hemoglobin leakage was observed along the whole ALS spinal cord axis and was most severe in the dorsal gray and white matter in the thoracic spinal cord. In contrast, motor neuron loss and TDP-43 proteinopathy were seen at all three levels of the ALS spinal cord, with most abundant TDP-43 deposition in the anterior gray matter of the cervical and lumbar cord. Our data show that leakage of the BSCB occurs during life, but at end-stage disease the regions with most severe BSCB damage are not those where TDP-43 accumulation is most abundant. This suggests BSCB leakage and TDP-43 pathology are independent pathologies in ALS.
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13
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Cook CN, Wu Y, Odeh HM, Gendron TF, Jansen-West K, Del Rosso G, Yue M, Jiang P, Gomes E, Tong J, Daughrity LM, Avendano NM, Castanedes-Casey M, Shao W, Oskarsson B, Tomassy GS, McCampbell A, Rigo F, Dickson DW, Shorter J, Zhang YJ, Petrucelli L. C9orf72 poly(GR) aggregation induces TDP-43 proteinopathy. Sci Transl Med 2021; 12:12/559/eabb3774. [PMID: 32878979 DOI: 10.1126/scitranslmed.abb3774] [Citation(s) in RCA: 102] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Accepted: 06/19/2020] [Indexed: 12/14/2022]
Abstract
TAR DNA-binding protein 43 (TDP-43) inclusions are a pathological hallmark of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS), including cases caused by G4C2 repeat expansions in the C9orf72 gene (c9FTD/ALS). Providing mechanistic insight into the link between C9orf72 mutations and TDP-43 pathology, we demonstrated that a glycine-arginine repeat protein [poly(GR)] translated from expanded G4C2 repeats was sufficient to promote aggregation of endogenous TDP-43. In particular, toxic poly(GR) proteins mediated sequestration of full-length TDP-43 in an RNA-independent manner to induce cytoplasmic TDP-43 inclusion formation. Moreover, in GFP-(GR)200 mice, poly(GR) caused the mislocalization of nucleocytoplasmic transport factors and nuclear pore complex proteins. These mislocalization events resulted in the aberrant accumulation of endogenous TDP-43 in the cytoplasm where it co-aggregated with poly(GR). Last, we demonstrated that treating G4C2 repeat-expressing mice with repeat-targeting antisense oligonucleotides lowered poly(GR) burden, which was accompanied by reduced TDP-43 pathology and neurodegeneration, including lowering of plasma neurofilament light (NFL) concentration. These results contribute to clarification of the mechanism by which poly(GR) drives TDP-43 proteinopathy, confirm that G4C2-targeted therapeutics reduce TDP-43 pathology in vivo, and demonstrate that alterations in plasma NFL provide insight into the therapeutic efficacy of disease-modifying treatments.
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Affiliation(s)
- Casey N Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Yanwei Wu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Hana M Odeh
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Karen Jansen-West
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Giulia Del Rosso
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Mei Yue
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Peizhou Jiang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Edward Gomes
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Jimei Tong
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Nicole M Avendano
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Wei Shao
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Björn Oskarsson
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | | | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, USA
| | - Dennis W Dickson
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Yong-Jie Zhang
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA. .,Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA. .,Neurobiology of Disease Graduate Program, Mayo Graduate School, Mayo Clinic College of Medicine, Rochester, MN 55902, USA
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14
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Chua JP, De Calbiac H, Kabashi E, Barmada SJ. Autophagy and ALS: mechanistic insights and therapeutic implications. Autophagy 2021; 18:254-282. [PMID: 34057020 PMCID: PMC8942428 DOI: 10.1080/15548627.2021.1926656] [Citation(s) in RCA: 51] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Mechanisms of protein homeostasis are crucial for overseeing the clearance of misfolded and toxic proteins over the lifetime of an organism, thereby ensuring the health of neurons and other cells of the central nervous system. The highly conserved pathway of autophagy is particularly necessary for preventing and counteracting pathogenic insults that may lead to neurodegeneration. In line with this, mutations in genes that encode essential autophagy factors result in impaired autophagy and lead to neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS). However, the mechanistic details underlying the neuroprotective role of autophagy, neuronal resistance to autophagy induction, and the neuron-specific effects of autophagy-impairing mutations remain incompletely defined. Further, the manner and extent to which non-cell autonomous effects of autophagy dysfunction contribute to ALS pathogenesis are not fully understood. Here, we review the current understanding of the interplay between autophagy and ALS pathogenesis by providing an overview of critical steps in the autophagy pathway, with special focus on pivotal factors impaired by ALS-causing mutations, their physiologic effects on autophagy in disease models, and the cell type-specific mechanisms regulating autophagy in non-neuronal cells which, when impaired, can contribute to neurodegeneration. This review thereby provides a framework not only to guide further investigations of neuronal autophagy but also to refine therapeutic strategies for ALS and related neurodegenerative diseases.Abbreviations: ALS: amyotrophic lateral sclerosis; Atg: autophagy-related; CHMP2B: charged multivesicular body protein 2B; DPR: dipeptide repeat; FTD: frontotemporal dementia; iPSC: induced pluripotent stem cell; LIR: LC3-interacting region; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MTOR: mechanistic target of rapamycin kinase; PINK1: PTEN induced kinase 1; RNP: ribonuclear protein; sALS: sporadic ALS; SPHK1: sphingosine kinase 1; TARDBP/TDP-43: TAR DNA binding protein; TBK1: TANK-binding kinase 1; TFEB: transcription factor EB; ULK: unc-51 like autophagy activating kinase; UPR: unfolded protein response; UPS: ubiquitin-proteasome system; VCP: valosin containing protein.
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Affiliation(s)
- Jason P Chua
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
| | - Hortense De Calbiac
- Recherche translationnelle sur les maladies neurologiques, Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - Edor Kabashi
- Recherche translationnelle sur les maladies neurologiques, Institut Imagine, UMR-1163 INSERM et Université Paris Descartes, Hôpital Universitaire Necker-Enfants Malades, Paris, France
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States
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15
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Schmitz A, Pinheiro Marques J, Oertig I, Maharjan N, Saxena S. Emerging Perspectives on Dipeptide Repeat Proteins in C9ORF72 ALS/FTD. Front Cell Neurosci 2021; 15:637548. [PMID: 33679328 PMCID: PMC7930069 DOI: 10.3389/fncel.2021.637548] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 01/07/2021] [Indexed: 11/13/2022] Open
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide expansion in the chromosome 9 open reading frame 72 gene (C9ORF72). This hexanucleotide expansion consists of GGGGCC (G4C2) repeats that have been implicated to lead to three main modes of disease pathology: loss of function of the C9ORF72 protein, the generation of RNA foci, and the production of dipeptide repeat proteins (DPRs) through repeat-associated non-AUG (RAN) translation. Five different DPRs are currently known to be formed: glycine-alanine (GA) and glycine-arginine (GR) from the sense strand, proline-alanine (PA), and proline-arginine (PR) from the antisense strand, and glycine-proline (GP) from both strands. The exact contribution of each DPR to disease pathology is currently under intense scrutiny and is still poorly understood. However, recent advances in both neuropathological and cellular studies have provided us with clues enabling us to better understand the effect of individual DPRs on disease pathogenesis. In this review, we compile the current knowledge of specific DPR involvement on disease development and highlight recent advances, such as the impact of arginine-rich DPRs on nucleolar protein quality control, the correlation of poly-GR with neurodegeneration, and the possible involvement of chimeric DPR species. Further, we discuss recent findings regarding the mechanisms of RAN translation, its modulators, and other promising therapeutic options.
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Affiliation(s)
- Alexander Schmitz
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - João Pinheiro Marques
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Irina Oertig
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Niran Maharjan
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Smita Saxena
- Department of Neurology, Center for Experimental Neurology, Inselspital University Hospital, Bern, Switzerland
- Department for BioMedical Research (DBMR), University of Bern, Bern, Switzerland
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16
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Fluid Biomarkers of Frontotemporal Lobar Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1281:123-139. [PMID: 33433873 DOI: 10.1007/978-3-030-51140-1_9] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A timely diagnosis of frontotemporal degeneration (FTD) is frequently challenging due to the heterogeneous symptomatology and poor phenotype-pathological correlation. Fluid biomarkers that reflect FTD pathophysiology could be instrumental in both clinical practice and pharmaceutical trials. In recent years, significant progress has been made in developing biomarkers of neurodegenerative diseases: amyloid-β and tau in cerebrospinal fluid (CSF) can be used to exclude Alzheimer's disease, while neurofilament light chain (NfL) is emerging as a promising, albeit nonspecific, marker of neurodegeneration in both CSF and blood. Gene-specific biomarkers such as PGRN in GRN mutation carriers and dipeptide repeat proteins in C9orf72 mutation carriers are potential target engagement markers in genetic FTD trials. Novel techniques capable of measuring very low concentrations of brain-derived proteins in peripheral fluids are facilitating studies of blood biomarkers as a minimally invasive alternative to CSF. A major remaining challenge is the identification of a biomarker that can be used to predict the neuropathological substrate in sporadic FTD patients.
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17
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Gagliardi D, Costamagna G, Taiana M, Andreoli L, Biella F, Bersani M, Bresolin N, Comi GP, Corti S. Insights into disease mechanisms and potential therapeutics for C9orf72-related amyotrophic lateral sclerosis/frontotemporal dementia. Ageing Res Rev 2020; 64:101172. [PMID: 32971256 DOI: 10.1016/j.arr.2020.101172] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Accepted: 08/31/2020] [Indexed: 12/12/2022]
Abstract
In 2011, a hexanucleotide repeat expansion (HRE) in the noncoding region of C9orf72 was associated with the most frequent genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The main pathogenic mechanisms in C9-ALS/FTD are haploinsufficiency of the C9orf72 protein and gain of function toxicity from bidirectionally-transcribed repeat-containing RNAs and dipeptide repeat proteins (DPRs) resulting from non-canonical RNA translation. Additionally, abnormalities in different downstream cellular mechanisms, such as nucleocytoplasmic transport and autophagy, play a role in pathogenesis. Substantial research efforts using in vitro and in vivo models have provided valuable insights into the contribution of each mechanism in disease pathogenesis. However, conflicting evidence exists, and a unifying theory still lacks. Here, we provide an overview of the recently published literature on clinical, neuropathological and molecular features of C9-ALS/FTD. We highlight the supposed neuronal role of C9orf72 and the HRE pathogenic cascade, mainly focusing on the contribution of RNA foci and DPRs to neurodegeneration and discussing the several downstream mechanisms. We summarize the emerging biochemical and neuroimaging biomarkers, as well as the potential therapeutic approaches. Despite promising results, a specific disease-modifying treatment is still not available to date and greater insights into disease mechanisms may help in this direction.
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Affiliation(s)
- Delia Gagliardi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Gianluca Costamagna
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Michela Taiana
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Luca Andreoli
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Fabio Biella
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Margherita Bersani
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy
| | - Nereo Bresolin
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Giacomo Pietro Comi
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy
| | - Stefania Corti
- Dino Ferrari Centre, Neuroscience Section, Department of Pathophysiology and Transplantation (DEPT), University of Milan, Via Francesco Sforza 35, 20122 Milan, Italy; Neurology Unit, IRCCS Foundation Ca' Granda Ospedale Maggiore Policlinico, Via Francesco Sforza 35, 20122, Milan, Italy.
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18
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Soluble and insoluble dipeptide repeat protein measurements in C9orf72-frontotemporal dementia brains show regional differential solubility and correlation of poly-GR with clinical severity. Acta Neuropathol Commun 2020; 8:184. [PMID: 33168090 PMCID: PMC7650212 DOI: 10.1186/s40478-020-01036-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/06/2020] [Indexed: 12/14/2022] Open
Abstract
A C9orf72 repeat expansion is the most common genetic cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis. One of the suggested pathomechanisms is toxicity from dipeptide repeat proteins (DPRs), which are generated via unconventional translation of sense and antisense repeat transcripts with poly-GA, poly-GP and poly-GR being the most abundant dipeptide proteins. Animal and cellular studies highlight a neurotoxic role of poly-GR and poly-PR and to a lesser degree of poly-GA. Human post-mortem studies in contrast have been much less clear on a potential role of DPR toxicity but have largely focused on immunohistochemical methods to detect aggregated DPR inclusions. This study uses protein fractionation and sensitive immunoassays to quantify not only insoluble but also soluble poly-GA, poly-GP and poly-GR concentrations in brain homogenates of FTD patients with C9orf72 mutation across four brain regions. We show that soluble DPRs are less abundant in clinically affected areas (i.e. frontal and temporal cortices). In contrast, the cerebellum not only shows the largest DPR load but also the highest relative DPR solubility. Finally, poly-GR levels and poly-GP solubility correlate with clinical severity. These findings provide the first cross-comparison of soluble and insoluble forms of all sense DPRs and shed light on the distribution and role of soluble DPRs in the etiopathogenesis of human C9orf72-FTD.
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19
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Yang Q, Jiao B, Shen L. The Development of C9orf72-Related Amyotrophic Lateral Sclerosis and Frontotemporal Dementia Disorders. Front Genet 2020; 11:562758. [PMID: 32983232 PMCID: PMC7492664 DOI: 10.3389/fgene.2020.562758] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022] Open
Abstract
The expanded GGGGCC hexanucleotide repeat in the non-coding region of the C9orf72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). There are three main disease mechanisms: loss of function of C9ORF72 protein, gain of function from the accumulation of sense and antisense (GGGGCC)n in RNA, and from the production of toxic dipeptides repeat proteins (DPRs) by non-AUG initiated translation. While many of the downstream mechanisms have been identified, the specific pathogenic pathway is still unclear. In this article, we provide an overview on the currently available literature and propose several hypotheses: (1) The pathogenesis of C9orf72-associated ALS/FTD, which cannot be explained by a single mechanism, involves a dual mechanism of both loss and gain of function. (2) The loss of function and gain of function can cause TDP-43 aggregation and damage nucleocytoplasmic transport. (3) Neurodegeneration can be caused by an accumulation of toxic substances in neurons themselves. In addition, we suggest that microglia may cause neurodegeneration by releasing inflammatory factors to neurons. Finally, we summarize several of the most promising treatment strategies.
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Affiliation(s)
- Qijie Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Bin Jiao
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China.,National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, China
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20
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McEachin ZT, Parameswaran J, Raj N, Bassell GJ, Jiang J. RNA-mediated toxicity in C9orf72 ALS and FTD. Neurobiol Dis 2020; 145:105055. [PMID: 32829028 DOI: 10.1016/j.nbd.2020.105055] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/27/2020] [Accepted: 08/18/2020] [Indexed: 12/13/2022] Open
Abstract
A GGGGCC hexanucleotide repeat expansion in the first intron of C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia. Compelling evidence suggests that gain of toxicity from the bidirectionally transcribed repeat expanded RNAs plays a central role in disease pathogenesis. Two potential mechanisms have been proposed including RNA-mediated toxicity and/or the production of toxic dipeptide repeat proteins. In this review, we focus on the role of RNA mediated toxicity in ALS/FTD caused by the C9orf72 mutation and discuss arguments for and against this mechanism. In addition, we summarize how G4C2 repeat RNAs can elicit toxicity and potential therapeutic strategies to mitigate RNA-mediated toxicity.
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Affiliation(s)
- Zachary T McEachin
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA.
| | | | - Nisha Raj
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Gary J Bassell
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA; Laboratory for Translational Cell Biology, Emory University, Atlanta, GA 30322, USA; Department of Neurology, Emory University, Atlanta, GA 30322, USA
| | - Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA.
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21
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Neumann M, Mackenzie IRA. Review: Neuropathology of non-tau frontotemporal lobar degeneration. Neuropathol Appl Neurobiol 2020; 45:19-40. [PMID: 30357887 DOI: 10.1111/nan.12526] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Accepted: 09/29/2018] [Indexed: 12/12/2022]
Abstract
Frontotemporal dementia (FTD) is a heterogeneous clinical syndrome associated with frontotemporal lobar degeneration (FTLD) as a relatively consistent neuropathological hallmark feature. However, the discoveries in the past decade of many of the relevant pathological proteins aggregating in human FTD brains in addition to several new FTD causing gene mutations underlined that FTD is a diverse condition on the neuropathological and genetic basis. This resulted in a novel molecular classification of these conditions based on the predominant protein abnormality and allows most cases of FTD to be placed now into one of three broad molecular subgroups; FTLD with tau, TAR DNA-binding protein 43 or FET protein accumulation (FTLD-tau, FTLD-TDP and FTLD-FET respectively). This review will provide an overview of the molecular neuropathology of non-tau FTLD, insights into disease mechanisms gained from the study of human post mortem tissue as well as discussion of current controversies in the field.
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Affiliation(s)
- M Neumann
- Department of Neuropathology, University Hospital of Tübingen, Tübingen, Germany.,Molecular Neuropathology of Neurodegenerative Diseases, German Center for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - I R A Mackenzie
- Department of Pathology, University of British Columbia and Vancouver General Hospital, Vancouver, BC, Canada
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22
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Jensen BK, Schuldi MH, McAvoy K, Russell KA, Boehringer A, Curran BM, Krishnamurthy K, Wen X, Westergard T, Ma L, Haeusler AR, Edbauer D, Pasinelli P, Trotti D. Synaptic dysfunction induced by glycine-alanine dipeptides in C9orf72-ALS/FTD is rescued by SV2 replenishment. EMBO Mol Med 2020; 12:e10722. [PMID: 32347002 PMCID: PMC7207170 DOI: 10.15252/emmm.201910722] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 03/23/2020] [Accepted: 03/26/2020] [Indexed: 12/16/2022] Open
Abstract
The most common cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is an intronic hexanucleotide repeat expansion in the C9orf72 gene. In disease, RNA transcripts containing this expanded region undergo repeat-associated non-AUG translation to produce dipeptide repeat proteins (DPRs), which are detected in brain and spinal cord of patients and are neurotoxic both in vitro and in vivo paradigms. We reveal here a novel pathogenic mechanism for the most abundantly detected DPR in ALS/FTD autopsy tissues, poly-glycine-alanine (GA). Previously, we showed motor dysfunction in a GA mouse model without loss of motor neurons. Here, we demonstrate that mobile GA aggregates are present within neurites, evoke a reduction in synaptic vesicle-associated protein 2 (SV2), and alter Ca2+ influx and synaptic vesicle release. These phenotypes could be corrected by restoring SV2 levels. In GA mice, loss of SV2 was observed without reduction of motor neuron number. Notably, reduction in SV2 was seen in cortical and motor neurons derived from patient induced pluripotent stem cell lines, suggesting synaptic alterations also occur in patients.
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Affiliation(s)
- Brigid K Jensen
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Martin H Schuldi
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
| | - Kevin McAvoy
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Katelyn A Russell
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Ashley Boehringer
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Bridget M Curran
- Department of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Karthik Krishnamurthy
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Xinmei Wen
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Thomas Westergard
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Le Ma
- Department of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Aaron R Haeusler
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Dieter Edbauer
- German Center for Neurodegenerative Diseases (DZNE)MunichGermany
| | - Piera Pasinelli
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
| | - Davide Trotti
- Jefferson Weinberg ALS CenterDepartment of NeuroscienceVickie and Jack Farber Institute for NeuroscienceThomas Jefferson UniversityPhiladelphiaPAUSA
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23
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Brasseur L, Coens A, Waeytens J, Melki R, Bousset L. Dipeptide repeat derived from C9orf72 hexanucleotide expansions forms amyloids or natively unfolded structures in vitro. Biochem Biophys Res Commun 2020; 526:410-416. [PMID: 32223927 DOI: 10.1016/j.bbrc.2020.03.108] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/14/2022]
Abstract
The abnormal repetition of the hexanucleotide GGGGCC within the C9orf72 gene is the most common genetic cause of both Amyotrophic Lateral Sclerosis (ALS) and Frontotemporal Dementia (FTD). Different hypothesis have been proposed to explain the pathogenicity of this mutation. Among them, the production of aberrant proteins called Dipeptide Repeat Proteins (DPR) from the repeated sequence. Those proteins are of interest, as they are toxic and form insoluble deposits in patient brains. In this study, we characterized the structural features of three different DPR encoded by the hexanucleotide repeat GGGGCC, namely poly-GA, poly-GP and poly-PA. We showed that DPR are natively unstructured proteins and that only poly-GA forms in vitro fibrillary aggregates. Poly-GA fibrils are of amyloid nature as revealed by their high content in beta sheets. They neither bind Thioflavin T nor Primuline, the commonly used amyloid fluorescent dyes. Remarkably, not all of the poly-GA primary structure was part of fibrils amyloid core.
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Affiliation(s)
- Laurent Brasseur
- Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Laboratoire des Maladies Neurodégénératives, Centre National de la Recherche Scientifique (CNRS), Paris, Fontenay-aux-Roses, F-92265, France.
| | - Audrey Coens
- Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Laboratoire des Maladies Neurodégénératives, Centre National de la Recherche Scientifique (CNRS), Paris, Fontenay-aux-Roses, F-92265, France.
| | - Jehan Waeytens
- Laboratoire de Chimie Physique, CNRS, UMR 8000, Université Paris-Sud, Orsay, France; Structure et Fonction des Membranes Biologiques, Université libre de Bruxelles, Bruxelles, Belgium.
| | - Ronald Melki
- Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Laboratoire des Maladies Neurodégénératives, Centre National de la Recherche Scientifique (CNRS), Paris, Fontenay-aux-Roses, F-92265, France.
| | - Luc Bousset
- Institut de Biologie François Jacob, Molecular Imaging Research Center (MIRCen), Commissariat à l'Energie Atomique et aux Energies Alternatives (CEA), Direction de la Recherche Fondamentale (DRF), Laboratoire des Maladies Neurodégénératives, Centre National de la Recherche Scientifique (CNRS), Paris, Fontenay-aux-Roses, F-92265, France.
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24
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Nucleocytoplasmic Proteomic Analysis Uncovers eRF1 and Nonsense-Mediated Decay as Modifiers of ALS/FTD C9orf72 Toxicity. Neuron 2020; 106:90-107.e13. [PMID: 32059759 DOI: 10.1016/j.neuron.2020.01.020] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 12/08/2019] [Accepted: 01/15/2020] [Indexed: 12/13/2022]
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is a hexanucleotide repeat expansion in C9orf72 (C9-HRE). While RNA and dipeptide repeats produced by C9-HRE disrupt nucleocytoplasmic transport, the proteins that become redistributed remain unknown. Here, we utilized subcellular fractionation coupled with tandem mass spectrometry and identified 126 proteins, enriched for protein translation and RNA metabolism pathways, which collectively drive a shift toward a more cytosolic proteome in C9-HRE cells. Among these was eRF1, which regulates translation termination and nonsense-mediated decay (NMD). eRF1 accumulates within elaborate nuclear envelope invaginations in patient induced pluripotent stem cell (iPSC) neurons and postmortem tissue and mediates a protective shift from protein translation to NMD-dependent mRNA degradation. Overexpression of eRF1 and the NMD driver UPF1 ameliorate C9-HRE toxicity in vivo. Our findings provide a resource for proteome-wide nucleocytoplasmic alterations across neurodegeneration-associated repeat expansion mutations and highlight eRF1 and NMD as therapeutic targets in C9orf72-associated ALS and/or FTD.
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25
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Swinnen B, Robberecht W, Van Den Bosch L. RNA toxicity in non-coding repeat expansion disorders. EMBO J 2020; 39:e101112. [PMID: 31721251 PMCID: PMC6939197 DOI: 10.15252/embj.2018101112] [Citation(s) in RCA: 113] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 09/30/2019] [Accepted: 10/09/2019] [Indexed: 12/11/2022] Open
Abstract
Several neurodegenerative disorders like amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia (SCA) are caused by non-coding nucleotide repeat expansions. Different pathogenic mechanisms may underlie these non-coding repeat expansion disorders. While gain-of-function mechanisms, such as toxicity associated with expression of repeat RNA or toxicity associated with repeat-associated non-ATG (RAN) products, are most frequently connected with these disorders, loss-of-function mechanisms have also been implicated. We review the different pathways that have been linked to non-coding repeat expansion disorders such as C9ORF72-linked ALS/frontotemporal dementia (FTD), myotonic dystrophy, fragile X tremor/ataxia syndrome (FXTAS), SCA, and Huntington's disease-like 2. We discuss modes of RNA toxicity focusing on the identity and the interacting partners of the toxic RNA species. Using the C9ORF72 ALS/FTD paradigm, we further explore the efforts and different methods used to disentangle RNA vs. RAN toxicity. Overall, we conclude that there is ample evidence for a role of RNA toxicity in non-coding repeat expansion diseases.
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Affiliation(s)
- Bart Swinnen
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
- Department of NeurologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Wim Robberecht
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
- Department of NeurologyUniversity Hospitals LeuvenLeuvenBelgium
| | - Ludo Van Den Bosch
- Department of NeurosciencesExperimental NeurologyLeuven Brain Institute (LBI)KU Leuven – University of LeuvenLeuvenBelgium
- Laboratory of NeurobiologyVIB, Center for Brain & Disease ResearchLeuvenBelgium
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26
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Cook C, Petrucelli L. Genetic Convergence Brings Clarity to the Enigmatic Red Line in ALS. Neuron 2019; 101:1057-1069. [PMID: 30897357 DOI: 10.1016/j.neuron.2019.02.032] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 02/07/2019] [Accepted: 02/19/2019] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is an aggressive neurodegenerative disorder that orchestrates an attack on the motor nervous system that is unrelenting. Recent discoveries into the pathogenic consequences of repeat expansions in C9ORF72, which are the most common genetic cause of ALS, combined with the identification of new genetic mutations are providing novel insight into the underlying mechanism(s) that cause ALS. In particular, the myriad of functions linked to ALS-associated genes have collectively implicated four main pathways in disease pathogenesis, including RNA metabolism and translational biology; protein quality control; cytoskeletal integrity and trafficking; and mitochondrial function and transport. Through the identification of common disease mechanisms on which multiple ALS genes converge, key targets for potential therapeutic intervention are highlighted.
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Affiliation(s)
- Casey Cook
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL, USA; Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL, USA.
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27
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Yang Y, Halliday GM, Kiernan MC, Tan RH. TDP-43 levels in the brain tissue of ALS cases with and without C9ORF72 or ATXN2 gene expansions. Neurology 2019; 93:e1748-e1755. [PMID: 31619481 DOI: 10.1212/wnl.0000000000008439] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/17/2019] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE To assess the amount of phosphorylated and nonphosphorylated TAR DNA-binding protein 43 (TDP-43) in the motor brain regions of cases of amyotrophic lateral sclerosis (ALS) with and without repeat expansions in the ATXN2 or C9ORF72 genes. METHODS The 45-kDa phosphorylated form of TDP-43 and 43-kDa nonphosphorylated form of TDP-43 were quantified by immunoblot in postmortem brain tissue from the motor cortex, spinal cord, and cerebellar vermis of 23 cases with ALS with repeat expansions in the ATXN2 or C9ORF72 genes and sporadic disease and 10 controls. RESULTS Significantly greater levels of phosphorylated TDP-43 were identified in the motor cortex of cases with ALS with C9ORF72 expansions, and significantly greater amounts of phosphorylated TDP-43 were found in the spinal cord of cases with ALS with intermediate ATXN2 expansions. In contrast, however, similar levels of nonphosphorylated TDP-43 were found in all 3 regions between ALS groups. CONCLUSION Despite its central role in the pathogenesis of ALS and the emergence of potential targets to modify its aggregation, TDP-43 levels have not been quantified in pathologically confirmed cases with ALS. The present results demonstrating significant differences in phosphorylated but not nonphosphorylated TDP-43 levels suggest that different posttranslational modifications are involved in the generation of greater pathologic TDP-43 levels identified here in our cohort of cases with genetic expansions. These findings are consistent with emerging studies implicating distinct pathomechanisms in the generation of pathologic TDP-43 in cases with ALS with C9ORF72 or ATXN2 expansions and are of relevance to therapeutic research aimed at reducing pathologic TDP-43 in all or a subset of patients with ALS.
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Affiliation(s)
- Yue Yang
- From the University of Sydney (Y.Y., G.M.H., M.C.K., R.H.T.), Brain and Mind Centre and Central Clinical School, Faculty of Medicine and Health; School of Medical Sciences (G.M.H., R.H.T.), University of New South Wales; Neuroscience Research Australia (G.M.H., R.H.T.); and Department of Neurology (M.C.K.), Royal Prince Alfred Hospital, Sydney, Australia
| | - Glenda M Halliday
- From the University of Sydney (Y.Y., G.M.H., M.C.K., R.H.T.), Brain and Mind Centre and Central Clinical School, Faculty of Medicine and Health; School of Medical Sciences (G.M.H., R.H.T.), University of New South Wales; Neuroscience Research Australia (G.M.H., R.H.T.); and Department of Neurology (M.C.K.), Royal Prince Alfred Hospital, Sydney, Australia
| | - Matthew C Kiernan
- From the University of Sydney (Y.Y., G.M.H., M.C.K., R.H.T.), Brain and Mind Centre and Central Clinical School, Faculty of Medicine and Health; School of Medical Sciences (G.M.H., R.H.T.), University of New South Wales; Neuroscience Research Australia (G.M.H., R.H.T.); and Department of Neurology (M.C.K.), Royal Prince Alfred Hospital, Sydney, Australia
| | - Rachel H Tan
- From the University of Sydney (Y.Y., G.M.H., M.C.K., R.H.T.), Brain and Mind Centre and Central Clinical School, Faculty of Medicine and Health; School of Medical Sciences (G.M.H., R.H.T.), University of New South Wales; Neuroscience Research Australia (G.M.H., R.H.T.); and Department of Neurology (M.C.K.), Royal Prince Alfred Hospital, Sydney, Australia.
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28
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Jiang J, Ravits J. Pathogenic Mechanisms and Therapy Development for C9orf72 Amyotrophic Lateral Sclerosis/Frontotemporal Dementia. Neurotherapeutics 2019; 16:1115-1132. [PMID: 31667754 PMCID: PMC6985338 DOI: 10.1007/s13311-019-00797-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In 2011, a hexanucleotide repeat expansion in the first intron of the C9orf72 gene was identified as the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The proposed disease mechanisms include loss of C9orf72 function and gain of toxicity from the bidirectionally transcribed repeat-containing RNAs. Over the last few years, substantial progress has been made to determine the contribution of loss and gain of function in disease pathogenesis. The extensive body of molecular, cellular, animal, and human neuropathological studies is conflicted, but the predominance of evidence favors gain of toxicity as the main pathogenic mechanism for C9orf72 repeat expansions. Alterations in several downstream cellular functions, such as nucleocytoplasmic transport and autophagy, are implicated. Exciting progress has also been made in therapy development targeting this mutation, such as by antisense oligonucleotide therapies targeting sense transcripts and small molecules targeting nucleocytoplasmic transport, and these are now in phase 1 clinical trials.
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Affiliation(s)
- Jie Jiang
- Department of Cell Biology, Emory University, Atlanta, GA, 30322, USA.
| | - John Ravits
- Department of Neurosciences, University of California at San Diego, La Jolla, CA, 92093, USA.
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29
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Cykowski MD, Dickson DW, Powell SZ, Arumanayagam AS, Rivera AL, Appel SH. Dipeptide repeat (DPR) pathology in the skeletal muscle of ALS patients with C9ORF72 repeat expansion. Acta Neuropathol 2019; 138:667-670. [PMID: 31375896 PMCID: PMC6778061 DOI: 10.1007/s00401-019-02050-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/26/2019] [Accepted: 07/26/2019] [Indexed: 10/26/2022]
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30
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Bertrand A, Wen J, Rinaldi D, Houot M, Sayah S, Camuzat A, Fournier C, Fontanella S, Routier A, Couratier P, Pasquier F, Habert MO, Hannequin D, Martinaud O, Caroppo P, Levy R, Dubois B, Brice A, Durrleman S, Colliot O, Le Ber I. Early Cognitive, Structural, and Microstructural Changes in Presymptomatic C9orf72 Carriers Younger Than 40 Years. JAMA Neurol 2019; 75:236-245. [PMID: 29197216 DOI: 10.1001/jamaneurol.2017.4266] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Importance Presymptomatic carriers of chromosome 9 open reading frame 72 (C9orf72) mutation, the most frequent genetic cause of frontotemporal lobar degeneration and amyotrophic lateral sclerosis, represent the optimal target population for the development of disease-modifying drugs. Preclinical biomarkers are needed to monitor the effect of therapeutic interventions in this population. Objectives To assess the occurrence of cognitive, structural, and microstructural changes in presymptomatic C9orf72 carriers. Design, Setting, and Participants The PREV-DEMALS study is a prospective, multicenter, observational study of first-degree relatives of individuals carrying the C9orf72 mutation. Eighty-four participants entered the study between October 2015 and April 2017; 80 (95%) were included in cross-sectional analyses of baseline data. All participants underwent neuropsychological testing and magnetic resonance imaging; 63 (79%) underwent diffusion tensor magnetic resonance imaging. Gray matter volumes and diffusion tensor imaging metrics were calculated within regions of interest. Anatomical and microstructural differences between individuals who carried the C9orf72 mutation (C9+) and those who did not carry the C9orf72 mutation (C9-) were assessed using linear mixed-effects models. Data were analyzed from October 2015 to April 2017. Main Outcomes and Measures Differences in neuropsychological scores, gray matter volume, and white matter integrity between C9+ and C9- individuals. Results Of the 80 included participants, there were 41 C9+ individuals (24 [59%] female; mean [SD] age, 39.8 [11.1] years) and 39 C9- individuals (24 [62%] female; mean [SD] age, 45.2 [13.9] years). Compared with C9- individuals, C9+ individuals had lower mean (SD) praxis scores (163.4 [6.1] vs 165.3 [5.9]; P = .01) and intransitive gesture scores (34.9 [1.6] vs 35.7 [1.5]; P = .004), atrophy in 8 cortical regions of interest and in the right thalamus, and white matter alterations in 8 tracts. When restricting the analyses to participants younger than 40 years, compared with C9- individuals, C9+ individuals had lower praxis scores and intransitive gesture scores, atrophy in 4 cortical regions of interest and in the right thalamus, and white matter alterations in 2 tracts. Conclusions and Relevance Cognitive, structural, and microstructural alterations are detectable in young C9+ individuals. Early and subtle praxis alterations, underpinned by focal atrophy of the left supramarginal gyrus, may represent an early and nonevolving phenotype related to neurodevelopmental effects of C9orf72 mutation. White matter alterations reflect the future phenotype of frontotemporal lobar degeneration/amyotrophic lateral sclerosis, while atrophy appears more diffuse. Our results contribute to a better understanding of the preclinical phase of C9orf72 disease and of the respective contribution of magnetic resonance biomarkers. Trial Registration clinicaltrials.gov Identifier: NCT02590276.
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Affiliation(s)
- Anne Bertrand
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Aramis Project Team, Inria Research Center of Paris, Paris, France.,Department of Neuroradiology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Department of Radiology, Hôpital Saint Antoine, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Junhao Wen
- Aramis Project Team, Inria Research Center of Paris, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Daisy Rinaldi
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Démences Rares ou Précoces, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Marion Houot
- Institute of Memory and Alzheimer's Disease, Centre of Excellence of Neurodegenerative Disease, Department of Neurology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Sabrina Sayah
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Agnès Camuzat
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Clémence Fournier
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Sabrina Fontanella
- Aramis Project Team, Inria Research Center of Paris, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Alexandre Routier
- Aramis Project Team, Inria Research Center of Paris, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Philippe Couratier
- Department of Neurology, Amyotrophic Lateral Sclerosis Center, Centre Hospitalier Universitaire de Limoges, Limoges, France.,Limoges University, Institut d'Epidémiologie Neurologique et Neurologie Tropicale, Centre National de la Recherche Scientifique, Fédération de Recherche 3503, Institut Génomique, Environnement, Immunité, Santé et Thérapeutiques, Limoges, France
| | - Florence Pasquier
- Neurology Department, National Reference Center for Young Onset Dementia, Centre Hospitalier Régional Universitaire de Lille, INSERM U1171, Lille, France.,Equipe d'accueil 1046, Maladie d'Alzheimer et Pathologies Vasculaires, Lille University, Lille, France
| | - Marie-Odile Habert
- Department of Nuclear Medicine, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Laboratoire d'Imagerie Biomédicale, Sorbonne Universités, Université Pierre et Marie Curie Paris 06, INSERM U1146, Centre National de la Recherche Scientifique, UMR 7371, Paris, France
| | - Didier Hannequin
- Centre National de Référence pour les Malades Alzheimer Jeunes, Centre Hospitalier Universitaire de Rouen, INSERM 1245, Rouen, France.,Department of Neurology, Centre Hospitalier Universitaire de Rouen, Rouen, France
| | - Olivier Martinaud
- Centre National de Référence pour les Malades Alzheimer Jeunes, Centre Hospitalier Universitaire de Rouen, INSERM 1245, Rouen, France.,Department of Neurology, Centre Hospitalier Universitaire de Rouen, Rouen, France
| | - Paola Caroppo
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France.,Division of Neurology V and Neuropathology, Fondazione Istituto di Ricovero e Cura a Carattere Scientifico Istituto Neurologico Carlo Besta, Milano, Italy
| | - Richard Levy
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Démences Rares ou Précoces, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Institute of Memory and Alzheimer's Disease, Centre of Excellence of Neurodegenerative Disease, Department of Neurology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Bruno Dubois
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Démences Rares ou Précoces, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Institute of Memory and Alzheimer's Disease, Centre of Excellence of Neurodegenerative Disease, Department of Neurology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Alexis Brice
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
| | - Stanley Durrleman
- Aramis Project Team, Inria Research Center of Paris, Paris, France.,Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Paris, France
| | - Olivier Colliot
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Aramis Project Team, Inria Research Center of Paris, Paris, France.,Centre pour l'Acquisition et le Traitement des Images, Institut du Cerveau et la Moelle, Paris, France
| | - Isabelle Le Ber
- Sorbonne Universités, Université Pierre et Marie Curie Paris 06, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Institut du Cerveau et la Moelle, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Centre de Référence des Démences Rares ou Précoces, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France.,Institute of Memory and Alzheimer's Disease, Centre of Excellence of Neurodegenerative Disease, Department of Neurology, Hôpital Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris, Paris, France
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Abstract
The discovery that repeat expansions in the C9orf72 gene are a frequent cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) has revolutionized our understanding of these diseases. Substantial headway has been made in characterizing C9orf72-mediated disease and unravelling its underlying aetiopathogenesis. Three main disease mechanisms have been proposed: loss of function of the C9orf72 protein and toxic gain of function from C9orf72 repeat RNA or from dipeptide repeat proteins produced by repeat-associated non-ATG translation. Several downstream processes across a range of cellular functions have also been implicated. In this article, we review the pathological and mechanistic features of C9orf72-associated FTD and ALS (collectively termed C9FTD/ALS), the model systems used to study these conditions, and the probable initiators of downstream disease mechanisms. We suggest that a combination of upstream mechanisms involving both loss and gain of function and downstream cellular pathways involving both cell-autonomous and non-cell-autonomous effects contributes to disease progression.
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Affiliation(s)
- Rubika Balendra
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK.,Department of Genetics, Evolution and Environment, Institute of Healthy Ageing, UCL, London, UK
| | - Adrian M Isaacs
- Department of Neurodegenerative Disease, UCL Institute of Neurology, London, UK. .,UK Dementia Research Institute at UCL, UCL Institute of Neurology, London, UK.
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32
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Halpern M, Brennand KJ, Gregory J. Examining the relationship between astrocyte dysfunction and neurodegeneration in ALS using hiPSCs. Neurobiol Dis 2019; 132:104562. [PMID: 31381978 DOI: 10.1016/j.nbd.2019.104562] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/28/2019] [Accepted: 07/31/2019] [Indexed: 02/07/2023] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a complex and fatal neurodegenerative disease for which the causes of disease onset and progression remain unclear. Recent advances in human induced pluripotent stem cell (hiPSC)-based models permit the study of the genetic factors associated with ALS in patient-derived neural cell types, including motor neurons and glia. While astrocyte dysfunction has traditionally been thought to exacerbate disease progression, astrocytic dysfunction may play a more direct role in disease initiation and progression. Such non-cell autonomous mechanisms expand the potential targets of therapeutic intervention, but only a handful of ALS risk-associated genes have been examined for their impact on astrocyte dysfunction and neurodegeneration. This review summarizes what is currently known about astrocyte function in ALS and suggests ways in which hiPSC-based models can be used to more effectively study the role of astrocytes in neurodegenerative disease.
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Affiliation(s)
- Madeline Halpern
- Graduate School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America
| | - Kristen J Brennand
- Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America; Department of Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America; Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States of America.
| | - James Gregory
- Center for Genomics of Neurodegenerative Disease, New York Genome Center, New York, NY 10013, United States of America.
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Banez-Coronel M, Ranum LPW. Repeat-associated non-AUG (RAN) translation: insights from pathology. J Transl Med 2019; 99:929-942. [PMID: 30918326 PMCID: PMC7219275 DOI: 10.1038/s41374-019-0241-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 01/29/2019] [Indexed: 12/14/2022] Open
Abstract
More than 40 different neurological diseases are caused by microsatellite repeat expansions. Since the discovery of repeat-associated non-AUG (RAN) translation by Zu et al. in 2011, nine expansion disorders have been identified as RAN-positive diseases. RAN proteins are translated from different types of nucleotide repeat expansions and can be produced from both sense and antisense transcripts. In some diseases, RAN proteins have been shown to accumulate in affected brain regions. Here we review the pathological and molecular aspects associated with RAN protein accumulation for each particular disorder, the correlation between disease pathology and the available in vivo models and the common aspects shared by some of the newly discovered RAN proteins.
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Affiliation(s)
- Monica Banez-Coronel
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA
| | - Laura P W Ranum
- Center for NeuroGenetics, University of Florida, Gainesville, FL, 32610, USA.
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32610, USA.
- Department of Neurology, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.
- McKnight Brain Institute, University of Florida, Gainesville, FL, 32610, USA.
- Genetics Institute, University of Florida, Gainesville, FL, 32610, USA.
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34
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Gill C, Phelan JP, Hatzipetros T, Kidd JD, Tassinari VR, Levine B, Wang MZ, Moreno A, Thompson K, Maier M, Grimm J, Gill A, Vieira FG. SOD1-positive aggregate accumulation in the CNS predicts slower disease progression and increased longevity in a mutant SOD1 mouse model of ALS. Sci Rep 2019; 9:6724. [PMID: 31040321 PMCID: PMC6491559 DOI: 10.1038/s41598-019-43164-z] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 04/17/2019] [Indexed: 12/11/2022] Open
Abstract
Non-natively folded variants of superoxide dismutase 1 (SOD1) are thought to contribute to the pathogenesis of familial amyotrophic lateral sclerosis (ALS), however the relative toxicities of these variants are controversial. Here, we aimed to decipher the relationships between the different SOD1 variants (aggregated, soluble misfolded, soluble total) and the clinical presentation of ALS in the SOD1G93A mouse. Using a multi-approach strategy, we found that the CNS regions least affected by disease had the most aggregated SOD1. We also found that the levels of aggregated SOD1 in the spinal cord were inversely correlated with the disease progression. Conversely, in the most affected regions, we observed that there was a high soluble misfolded/soluble total SOD1 ratio. Taken together, these findings suggest that soluble misfolded SOD1 may be the disease driver in ALS, whereas aggregated SOD1 may serve to sequester the toxic species acting in a neuroprotective fashion.
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Affiliation(s)
- Cindy Gill
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - James P Phelan
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - Theo Hatzipetros
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - Joshua D Kidd
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | | | - Beth Levine
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - Monica Z Wang
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - Andrew Moreno
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | - Kenneth Thompson
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
| | | | - Jan Grimm
- Neurimmune AG, Schlieren-Zurich, Switzerland
| | - Alan Gill
- ALS Therapy Development Institute, Cambridge, Massachusetts, USA
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35
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Molecular Mechanisms of Neurodegeneration Related to C9orf72 Hexanucleotide Repeat Expansion. Behav Neurol 2019; 2019:2909168. [PMID: 30774737 PMCID: PMC6350563 DOI: 10.1155/2019/2909168] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 08/28/2018] [Accepted: 09/18/2018] [Indexed: 12/11/2022] Open
Abstract
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 (C9orf72) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2–10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
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36
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Vatsavayai SC, Nana AL, Yokoyama JS, Seeley WW. C9orf72-FTD/ALS pathogenesis: evidence from human neuropathological studies. Acta Neuropathol 2019; 137:1-26. [PMID: 30368547 DOI: 10.1007/s00401-018-1921-0] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 10/16/2018] [Accepted: 10/16/2018] [Indexed: 12/11/2022]
Abstract
What are the most important and treatable pathogenic mechanisms in C9orf72-FTD/ALS? Model-based efforts to address this question are forging ahead at a blistering pace, often with conflicting results. But what does the human neuropathological literature reveal? Here, we provide a critical review of the human studies to date, seeking to highlight key gaps or uncertainties in our knowledge. First, we engage the C9orf72-specific mechanisms, including C9orf72 haploinsufficiency, repeat RNA foci, and dipeptide repeat protein inclusions. We then turn to some of the most prominent C9orf72-associated features, such as TDP-43 loss-of-function, TDP-43 aggregation, and nuclear transport defects. Finally, we review potential disease-modifying epigenetic and genetic factors and the natural history of the disease across the lifespan. Throughout, we emphasize the importance of anatomical precision when studying how candidate mechanisms relate to neuronal, regional, and behavioral findings. We further highlight methodological approaches that may help address lingering knowledge gaps and uncertainties, as well as other logical next steps for the field. We conclude that anatomically oriented human neuropathological studies have a critical role to play in guiding this fast-moving field toward effective new therapies.
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Affiliation(s)
- Sarat C Vatsavayai
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Alissa L Nana
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - Jennifer S Yokoyama
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA
| | - William W Seeley
- Memory and Aging Center, Department of Neurology, University of California, San Francisco, USA.
- Department of Pathology, University of California, San Francisco, Box 1207, San Francisco, CA, 94143-1207, USA.
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37
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The C9ORF72 Gene, Implicated in Amyotrophic Lateral Sclerosis and Frontotemporal Dementia, Encodes a Protein That Functions in Control of Endothelin and Glutamate Signaling. Mol Cell Biol 2018; 38:MCB.00155-18. [PMID: 30150298 DOI: 10.1128/mcb.00155-18] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Accepted: 08/15/2018] [Indexed: 02/08/2023] Open
Abstract
A GGGGCC repeat expansion in the C9ORF72 (C9) gene is the most common known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Several mechanisms have been proposed to account for its toxicity, including the possibility that reduced C9 protein levels contribute to disease. To investigate this possibility, we examined the effects of reduced C9 levels in several cell systems. We first showed that C9 knockdown (KD) in U87 glioblastoma cells results in striking morphological changes, including vacuolization and alterations in cell size. Unexpectedly, RNA analysis revealed changes in expression of many genes, including genes involved in endothelin (EDN) signaling and immune system pathways and multiple glutamate cycling genes (e.g., EAAT2), which were verified in several cell models, including astrocytes and brain samples from C9-positive patients. Consistent with deregulation of the glutamate cycling genes, elevated intracellular glutamate was detected in both KD cells and patient astrocytes. Importantly, levels of mRNAs encoding EDN1 and its receptors, known to be elevated in ALS, were sharply increased by C9 KD, likely resulting from an observed activation of NF-κB signaling and/or a possible role of a C9 isoform in gene control.
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38
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Lee YB, Baskaran P, Gomez-Deza J, Chen HJ, Nishimura AL, Smith BN, Troakes C, Adachi Y, Stepto A, Petrucelli L, Gallo JM, Hirth F, Rogelj B, Guthrie S, Shaw CE. C9orf72 poly GA RAN-translated protein plays a key role in amyotrophic lateral sclerosis via aggregation and toxicity. Hum Mol Genet 2018; 26:4765-4777. [PMID: 28973350 PMCID: PMC5886201 DOI: 10.1093/hmg/ddx350] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Accepted: 08/29/2017] [Indexed: 12/13/2022] Open
Abstract
An intronic GGGGCC (G4C2) hexanucleotide repeat expansion inC9orf72 is the most common genetic cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Repeat-associated non-AUG (RAN) translation of G4C2 RNA can result in five different dipeptide repeat proteins (DPR: poly GA, poly GP, poly GR, poly PA, and poly PR), which aggregate into neuronal cytoplasmic and nuclear inclusions in affected patients, however their contribution to disease pathogenesis remains controversial. We show that among the DPR proteins, expression of poly GA in a cell culture model activates programmed cell death and TDP-43 cleavage in a dose-dependent manner. Dual expression of poly GA together with other DPRs revealed that poly GP and poly PA are sequestered by poly GA, whereas poly GR and poly PR are rarely co-localised with poly GA. Dual expression of poly GA and poly PA ameliorated poly GA toxicity by inhibiting poly GA aggregation both in vitro and in vivo in the chick embryonic spinal cord. Expression of alternative codon-derived DPRs in chick embryonic spinal cord confirmed in vitro data, revealing that each of the dipeptides caused toxicity, with poly GA being the most toxic. Further, in vivo expression of G4C2 repeats of varying length caused apoptotic cell death, but failed to generate DPRs. Together, these data demonstrate that C9-related toxicity can be mediated by either RNA or DPRs. Moreover, our findings provide evidence that poly GA is a key mediator of cytotoxicity and that cross-talk between DPR proteins likely modifies their pathogenic status in C9ALS/FTD.
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Affiliation(s)
- Youn-Bok Lee
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Pranetha Baskaran
- Department of Developmental Neurobiology, King's College London, Guy's Campus, London SE1 1UL, UK
| | - Jorge Gomez-Deza
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Han-Jou Chen
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Agnes L Nishimura
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Bradley N Smith
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Claire Troakes
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Yoshitsugu Adachi
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Alan Stepto
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, FL 32224, USA
| | - Jean-Marc Gallo
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Frank Hirth
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
| | - Boris Rogelj
- Department of Biotechnology, Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia
| | - Sarah Guthrie
- Department of Developmental Neurobiology, King's College London, Guy's Campus, London SE1 1UL, UK.,School of Life Sciences, University of Sussex, JMS Building, Falmer Campus, Brighton, BN7 9QG UK
| | - Christopher E Shaw
- United Kingdom Dementia Research Institute Centre, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Camberwell, London SE5 9NU, UK
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Ito D, Hatano M, Suzuki N. RNA binding proteins and the pathological cascade in ALS/FTD neurodegeneration. Sci Transl Med 2018; 9:9/415/eaah5436. [PMID: 29118263 DOI: 10.1126/scitranslmed.aah5436] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/13/2016] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
Abstract
Advanced genetic approaches have accelerated the identification of causative genes linked to the neurodegenerative diseases amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Most of the disease-related proteins encoded by these genes form aggregates in the cellular machineries that regulate RNA and protein quality control in cells. Cross-talk among the signaling pathways governing these machineries leads to pathological cascades mediated by the accumulation of mutant RNA binding proteins. We outline the molecular basis of ALS and FTD pathogenesis and discuss the prospects for therapeutic strategies to treat these diseases.
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Affiliation(s)
- Daisuke Ito
- Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - Mami Hatano
- Department of Pathology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
| | - Norihiro Suzuki
- Department of Neurology, Keio University School of Medicine, Shinjuku-ku, Tokyo 160-8582, Japan
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40
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Gendron TF, Petrucelli L. Disease Mechanisms of C9ORF72 Repeat Expansions. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a024224. [PMID: 28130314 DOI: 10.1101/cshperspect.a024224] [Citation(s) in RCA: 56] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
G4C2 repeat expansions within the C9ORF72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These bidirectionally transcribed expansions lead to (1) the accumulation of sense G4C2 and antisense G2C4 repeat-containing RNA, (2) the production of proteins of repeating dipeptides through unconventional translation of these transcripts, and (3) decreased C9ORF72 mRNA and protein expression. Consequently, there is ample opportunity for the C9ORF72 mutation to give rise to a spectrum of clinical manifestations, ranging from muscle weakness and atrophy to changes in behavior and cognition. It is thus somewhat surprising that investigations of these three seemingly disparate events often converge on similar putative pathological mechanisms. This review aims to summarize the findings and questions emerging from the field's quest to decipher how C9ORF72 repeat expansions cause the devastating diseases collectively referred to as "c9ALS/FTD."
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Affiliation(s)
- Tania F Gendron
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida 32224
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic Florida, Jacksonville, Florida 32224
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41
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Saberi S, Stauffer JE, Jiang J, Garcia SD, Taylor AE, Schulte D, Ohkubo T, Schloffman CL, Maldonado M, Baughn M, Rodriguez MJ, Pizzo D, Cleveland D, Ravits J. Sense-encoded poly-GR dipeptide repeat proteins correlate to neurodegeneration and uniquely co-localize with TDP-43 in dendrites of repeat-expanded C9orf72 amyotrophic lateral sclerosis. Acta Neuropathol 2018; 135:459-474. [PMID: 29196813 PMCID: PMC5935138 DOI: 10.1007/s00401-017-1793-8] [Citation(s) in RCA: 134] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 11/25/2017] [Accepted: 11/26/2017] [Indexed: 12/12/2022]
Abstract
Hexanucleotide repeat expansions in C9orf72 are the most common genetic cause of amyotrophic lateral sclerosis (C9 ALS). The main hypothesized pathogenic mechanisms are C9orf72 haploinsufficiency and/or toxicity from one or more of bi-directionally transcribed repeat RNAs and their dipeptide repeat proteins (DPRs) poly-GP, poly-GA, poly-GR, poly-PR and poly-PA. Recently, nuclear import and/or export defects especially caused by arginine-containing poly-GR or poly-PR have been proposed as significant contributors to pathogenesis based on disease models. We quantitatively studied and compared DPRs, nuclear pore proteins and C9orf72 protein in clinically related and clinically unrelated regions of the central nervous system, and compared them to phosphorylated TDP-43 (pTDP-43), the hallmark protein of ALS. Of the five DPRs, only poly-GR was significantly abundant in clinically related areas compared to unrelated areas (p < 0.001), and formed dendritic-like aggregates in the motor cortex that co-localized with pTDP-43 (p < 0.0001). While most poly-GR dendritic inclusions were pTDP-43 positive, only 4% of pTDP-43 dendritic inclusions were poly-GR positive. Staining for arginine-containing poly-GR and poly-PR in nuclei of neurons produced signals that were not specific to C9 ALS. We could not detect significant differences of nuclear markers RanGap, Lamin B1, and Importin β1 in C9 ALS, although we observed subtle nuclear changes in ALS, both C9 and non-C9, compared to control. The C9orf72 protein itself was diffusely expressed in cytoplasm of large neurons and glia, and nearly 50% reduced, in both clinically related frontal cortex and unrelated occipital cortex, but not in cerebellum. In summary, sense-encoded poly-GR DPR was unique, and localized to dendrites and pTDP43 in motor regions of C9 ALS CNS. This is consistent with new emerging ideas about TDP-43 functions in dendrites.
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Affiliation(s)
- Shahram Saberi
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
- Department of Pathology, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy, Place Box 1194, New York, NY, 10029, USA
| | - Jennifer E Stauffer
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
- Jackson Laboratory, 600 Main St, Bar Harbor, ME, 04609, USA
| | - Jie Jiang
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
- Laboratory for Cell Biology, Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0670, USA
| | - Sandra Diaz Garcia
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Amy E Taylor
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Derek Schulte
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
- NeuroPace, Inc, 455 N. Bernardo Ave, Mountain View, CA, 94043, USA
| | - Takuya Ohkubo
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Cheyenne L Schloffman
- Laboratory for Cell Biology, Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0670, USA
| | - Marcus Maldonado
- Laboratory for Cell Biology, Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0670, USA
| | - Michael Baughn
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Maria J Rodriguez
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA
| | - Don Pizzo
- Department of Pathology, University of California at San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
| | - Don Cleveland
- Department of Cellular and Molecular Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093, USA
- Laboratory for Cell Biology, Ludwig Institute for Cancer Research, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0670, USA
| | - John Ravits
- Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA, 92093-0624, USA.
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42
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Maurel C, Dangoumau A, Marouillat S, Brulard C, Chami A, Hergesheimer R, Corcia P, Blasco H, Andres CR, Vourc'h P. Causative Genes in Amyotrophic Lateral Sclerosis and Protein Degradation Pathways: a Link to Neurodegeneration. Mol Neurobiol 2018; 55:6480-6499. [PMID: 29322304 DOI: 10.1007/s12035-017-0856-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 12/20/2017] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a disease caused by the degeneration of motor neurons (MNs) leading to progressive muscle weakness and atrophy. Several molecular pathways have been implicated, such as glutamate-mediated excitotoxicity, defects in cytoskeletal dynamics and axonal transport, disruption of RNA metabolism, and impairments in proteostasis. ALS is associated with protein accumulation in the cytoplasm of cells undergoing neurodegeneration, which is a hallmark of the disease. In this review, we focus on mechanisms of proteostasis, particularly protein degradation, and discuss how they are related to the genetics of ALS. Indeed, the genetic bases of the disease with the implication of more than 30 genes associated with familial ALS to date, together with the important increase in understanding of endoplasmic reticulum (ER) stress, proteasomal degradation, and autophagy, allow researchers to better understand the mechanisms underlying the selective death of motor neurons in ALS. It is clear that defects in proteostasis are involved in this type of cellular degeneration, but whether or not these mechanisms are primary causes or merely consequential remains to be clearly demonstrated. Novel cellular and animal models allowing chronic expression of mutant proteins, for example, are required. Further studies linking genetic discoveries in ALS to mechanisms of protein clearance will certainly be crucial in order to accelerate translational and clinical research towards new therapeutic targets and strategies.
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Affiliation(s)
- C Maurel
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Dangoumau
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - S Marouillat
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - C Brulard
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - A Chami
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - R Hergesheimer
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
| | - P Corcia
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Neurologie, CHRU de Tours, 37044, Tours, France
| | - H Blasco
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - C R Andres
- UMR INSERM U1253, Université de Tours, 37032, Tours, France
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France
| | - P Vourc'h
- UMR INSERM U1253, Université de Tours, 37032, Tours, France.
- Service de Biochimie et de Biologie Moléculaire, CHRU de Tours, 37044, Tours, France.
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43
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Kapur M, Monaghan CE, Ackerman SL. Regulation of mRNA Translation in Neurons-A Matter of Life and Death. Neuron 2017; 96:616-637. [PMID: 29096076 DOI: 10.1016/j.neuron.2017.09.057] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 09/20/2017] [Accepted: 09/28/2017] [Indexed: 12/14/2022]
Abstract
Dynamic regulation of mRNA translation initiation and elongation is essential for the survival and function of neural cells. Global reductions in translation initiation resulting from mutations in the translational machinery or inappropriate activation of the integrated stress response may contribute to pathogenesis in a subset of neurodegenerative disorders. Aberrant proteins generated by non-canonical translation initiation may be a factor in the neuron death observed in the nucleotide repeat expansion diseases. Dysfunction of central components of the elongation machinery, such as the tRNAs and their associated enzymes, can cause translational infidelity and ribosome stalling, resulting in neurodegeneration. Taken together, dysregulation of mRNA translation is emerging as a unifying mechanism underlying the pathogenesis of many neurodegenerative disorders.
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Affiliation(s)
- Mridu Kapur
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Caitlin E Monaghan
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Susan L Ackerman
- Howard Hughes Medical Institute, Department of Cellular and Molecular Medicine, Section of Neurobiology, University of California, San Diego, La Jolla, CA 92093, USA.
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44
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Polymenidou M, Cleveland DW. Biological Spectrum of Amyotrophic Lateral Sclerosis Prions. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024133. [PMID: 28062558 DOI: 10.1101/cshperspect.a024133] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) and frontotemporal lobar dementia (FTLD) are two neurodegenerative diseases with distinct clinical features but common genetic causes and neuropathological signatures. Ten years after the RNA-binding protein TDP-43 was discovered as the main protein in the cytoplasmic inclusions that characterize ALS and FTLD, their pathogenic mechanisms have never seemed more complex. Indeed, discoveries of the past decade have revolutionized our understanding of these diseases, highlighting their genetic heterogeneity and the involvement of protein-RNA assemblies in their pathogenesis. Importantly, these assemblies serve as the foci of protein misfolding and mature into insoluble structures, which further recruit native proteins, turning them into misfolded forms. This self-perpetuating mechanism is a twisted version of classical prion replication that leads to amplification of pathological protein complexes that spread throughout the neuraxis, offering a pathogenic principle that underlies the rapid disease progression that characterizes ALS and FTLD.
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Affiliation(s)
- Magdalini Polymenidou
- Institute of Molecular Life Sciences, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | - Don W Cleveland
- Ludwig Institute for Cancer Research and Department of Cellular and Molecular Medicine, University of California, 9500 Gilman Drive, San Diego, La Jolla, California 92093-0670
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45
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Abstract
Neurodegeneration is a leading cause of death in the developed world and a natural, albeit unfortunate, consequence of longer-lived populations. Despite great demand for therapeutic intervention, it is often the case that these diseases are insufficiently understood at the basic molecular level. What little is known has prompted much hopeful speculation about a generalized mechanistic thread that ties these disparate conditions together at the subcellular level and can be exploited for broad curative benefit. In this review, we discuss a prominent theory supported by genetic and pathological changes in an array of neurodegenerative diseases: that neurons are particularly vulnerable to disruption of RNA-binding protein dosage and dynamics. Here we synthesize the progress made at the clinical, genetic, and biophysical levels and conclude that this perspective offers the most parsimonious explanation for these mysterious diseases. Where appropriate, we highlight the reciprocal benefits of cross-disciplinary collaboration between disease specialists and RNA biologists as we envision a future in which neurodegeneration declines and our understanding of the broad importance of RNA processing deepens.
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Affiliation(s)
- Erin G Conlon
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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46
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Barker HV, Niblock M, Lee YB, Shaw CE, Gallo JM. RNA Misprocessing in C9orf72-Linked Neurodegeneration. Front Cell Neurosci 2017; 11:195. [PMID: 28744202 PMCID: PMC5504096 DOI: 10.3389/fncel.2017.00195] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Accepted: 06/21/2017] [Indexed: 12/12/2022] Open
Abstract
A large GGGGCC hexanucleotide repeat expansion in the first intron or promoter region of the C9orf72 gene is the most common genetic cause of familial and sporadic Amyotrophic lateral sclerosis (ALS), a devastating degenerative disease of motor neurons, and of Frontotemporal Dementia (FTD), the second most common form of presenile dementia after Alzheimer's disease. C9orf72-associated ALS/FTD is a multifaceted disease both in terms of its clinical presentation and the misregulated cellular pathways contributing to disease progression. Among the numerous pathways misregulated in C9orf72-associated ALS/FTD, altered RNA processing has consistently appeared at the forefront of C9orf72 research. This includes bidirectional transcription of the repeat sequence, accumulation of repeat RNA into nuclear foci sequestering specific RNA-binding proteins (RBPs) and translation of RNA repeats into dipeptide repeat proteins (DPRs) by repeat-associated non-AUG (RAN)-initiated translation. Over the past few years the true extent of RNA misprocessing in C9orf72-associated ALS/FTD has begun to emerge and disruptions have been identified in almost all aspects of the life of an RNA molecule, including release from RNA polymerase II, translation in the cytoplasm and degradation. Furthermore, several alterations have been identified in the processing of the C9orf72 RNA itself, in terms of its transcription, splicing and localization. This review article aims to consolidate our current knowledge on the consequence of the C9orf72 repeat expansion on RNA processing and draws attention to the mechanisms by which several aspects of C9orf72 molecular pathology converge to perturb every stage of RNA metabolism.
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Affiliation(s)
- Holly V. Barker
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondon, United Kingdom
| | - Michael Niblock
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondon, United Kingdom
| | - Youn-Bok Lee
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondon, United Kingdom
| | - Christopher E. Shaw
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondon, United Kingdom
| | - Jean-Marc Gallo
- Department of Basic and Clinical Neuroscience, Maurice Wohl Clinical Neuroscience Institute, Institute of Psychiatry, Psychology and Neuroscience, King’s College LondonLondon, United Kingdom
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47
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Shahheydari H, Ragagnin A, Walker AK, Toth RP, Vidal M, Jagaraj CJ, Perri ER, Konopka A, Sultana JM, Atkin JD. Protein Quality Control and the Amyotrophic Lateral Sclerosis/Frontotemporal Dementia Continuum. Front Mol Neurosci 2017; 10:119. [PMID: 28539871 PMCID: PMC5423993 DOI: 10.3389/fnmol.2017.00119] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 04/10/2017] [Indexed: 12/11/2022] Open
Abstract
Protein homeostasis, or proteostasis, has an important regulatory role in cellular function. Protein quality control mechanisms, including protein folding and protein degradation processes, have a crucial function in post-mitotic neurons. Cellular protein quality control relies on multiple strategies, including molecular chaperones, autophagy, the ubiquitin proteasome system, endoplasmic reticulum (ER)-associated degradation (ERAD) and the formation of stress granules (SGs), to regulate proteostasis. Neurodegenerative diseases are characterized by the presence of misfolded protein aggregates, implying that protein quality control mechanisms are dysfunctional in these conditions. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that are now recognized to overlap clinically and pathologically, forming a continuous disease spectrum. In this review article, we detail the evidence for dysregulation of protein quality control mechanisms across the whole ALS-FTD continuum, by discussing the major proteins implicated in ALS and/or FTD. We also discuss possible ways in which protein quality mechanisms could be targeted therapeutically in these disorders and highlight promising protein quality control-based therapeutics for clinical trials.
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Affiliation(s)
- Hamideh Shahheydari
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Audrey Ragagnin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Adam K Walker
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Reka P Toth
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Marta Vidal
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Cyril J Jagaraj
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Emma R Perri
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Anna Konopka
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Jessica M Sultana
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia
| | - Julie D Atkin
- Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie UniversitySydney, NSW, Australia.,Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe UniversityMelbourne, VIC, Australia
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48
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Stopford MJ, Higginbottom A, Hautbergue GM, Cooper-Knock J, Mulcahy PJ, De Vos KJ, Renton AE, Pliner H, Calvo A, Chio A, Traynor BJ, Azzouz M, Heath PR, Kirby J, Shaw PJ. C9ORF72 hexanucleotide repeat exerts toxicity in a stable, inducible motor neuronal cell model, which is rescued by partial depletion of Pten. Hum Mol Genet 2017; 26:1133-1145. [PMID: 28158451 PMCID: PMC5409131 DOI: 10.1093/hmg/ddx022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2016] [Revised: 01/02/2017] [Accepted: 01/10/2017] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating and incurable neurodegenerative disease, characterised by progressive failure of the neuromuscular system. A (G4C2)n repeat expansion in C9ORF72 is the most common genetic cause of ALS and frontotemporal dementia (FTD). To date, the balance of evidence indicates that the (G4C2)n repeat causes toxicity and neurodegeneration via a gain-of-toxic function mechanism; either through direct RNA toxicity or through the production of toxic aggregating dipeptide repeat proteins. Here, we have generated a stable and isogenic motor neuronal NSC34 cell model with inducible expression of a (G4C2)102 repeat, to investigate the gain-of-toxic function mechanisms. The expression of the (G4C2)102 repeat produces RNA foci and also undergoes RAN translation. In addition, the expression of the (G4C2)102 repeat shows cellular toxicity. Through comparison of transcriptomic data from the cellular model with laser-captured spinal motor neurons from C9ORF72-ALS cases, we also demonstrate that the PI3K/Akt cell survival signalling pathway is dysregulated in both systems. Furthermore, partial knockdown of Pten rescues the toxicity observed in the NSC34 (G4C2)102 cellular gain-of-toxic function model of C9ORF72-ALS. Our data indicate that PTEN may provide a potential therapeutic target to ameliorate toxic effects of the (G4C2)n repeat.
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Affiliation(s)
- Matthew J. Stopford
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Adrian Higginbottom
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Guillaume M. Hautbergue
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Johnathan Cooper-Knock
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Padraig J. Mulcahy
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Kurt J. De Vos
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Alan E. Renton
- Neuromuscular Diseases Research Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Hannah Pliner
- Neuromuscular Diseases Research Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Andrea Calvo
- Department of Neuroscience, University of Turin, Turin, Italy
| | - Adriano Chio
- Department of Neuroscience, University of Turin, Turin, Italy
| | - Bryan J. Traynor
- Neuromuscular Diseases Research Section, National Institute on Aging, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mimoun Azzouz
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Paul R. Heath
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | | | - Janine Kirby
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
| | - Pamela J. Shaw
- Department of Neuroscience, Sheffield Institute for Translational Neuroscience, University of Sheffield, Sheffield S10 2HQ, UK
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49
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Mann DMA, Snowden JS. Frontotemporal lobar degeneration: Pathogenesis, pathology and pathways to phenotype. Brain Pathol 2017; 27:723-736. [PMID: 28100023 DOI: 10.1111/bpa.12486] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 12/12/2022] Open
Abstract
Frontotemporal Lobar Degeneration (FTLD) is a clinically, pathologically and genetically heterogeneous group of disorders that affect principally the frontal and temporal lobes of the brain. There are three major associated clinical syndromes, behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SD) and progressive non-fluent aphasia (PNFA); three principal histologies, involving tau, TDP-43 and FUS proteins; and mutations in three major genes, MAPT, GRN and C9orf72, along with several other less common gene mutations. All three clinical syndromes can exist separately or in combination with Amyotrophic Lateral Sclerosis (ALS). SD is exclusively a TDP-43 proteinopathy, and PNFA may be so, with both showing tight clinical, histological and genetic inter-relationships. bvFTD is more of a challenge with overlapping histological and genetic features, involvement of any of the three aggregating proteins, and changes in any of the three major genes. However, when ALS is present, all cases show a clear histological phenotype with TDP-43 aggregated proteins, and familial forms are associated with expansions in C9orf72. TDP-43 and FUS are nuclear carrier proteins involved in the regulation of RNA metabolism, whereas tau protein - the product of MAPT - is responsible for the assembly/disassembly of microtubules, which are vital for intracellular transport. Mutations in TDP-43 and FUS genes are linked to clinical ALS rather than FTLD (with or without ALS), suggesting that clinical ALS may be a disorder of RNA metabolism. Conversely, the protein products of GRN and C9orf72, along with those of the other minor genes, appear to form part of the cellular protein degradation machinery. It is possible therefore that FTLD is a reflection of dysfunction within lysosomal/proteasomal systems resulting in failure to remove potentially neurotoxic (TDP-43 and tau) aggregates, which ultimately overwhelm capacity to function. Spread of aggregates along distinct pathways may account for the different clinical phenotypes, and patterns of progression of disease.
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Affiliation(s)
- David M A Mann
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Medical and Human Sciences, University of Manchester, Salford Royal Hospital, Salford, M6 8HD, UK
| | - Julie S Snowden
- Division of Neuroscience and Experimental Psychology, School of Biological Sciences, Faculty of Medical and Human Sciences, University of Manchester, Salford Royal Hospital, Salford, M6 8HD, UK.,Cerebral Function Unit, Greater Manchester Neurosciences Centre, Salford Royal Hospital, Stott Lane, Salford, M6 8HD, UK
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50
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Freibaum BD, Taylor JP. The Role of Dipeptide Repeats in C9ORF72-Related ALS-FTD. Front Mol Neurosci 2017; 10:35. [PMID: 28243191 PMCID: PMC5303742 DOI: 10.3389/fnmol.2017.00035] [Citation(s) in RCA: 174] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Accepted: 01/30/2017] [Indexed: 12/13/2022] Open
Abstract
Expansion of a hexanucleotide (GGGGCC) repeat in the gene chromosome 9 open reading frame 72 (C9ORF72) is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (FTD). Three non-exclusive mechanisms have been proposed to contribute to the pathology initiated by this genetic insult. First, it was suggested that decreased expression of the C9orf72 protein product may contribute to disease. Second, the recognition that C9ORF72-related disease is associated with accumulation of GGGGCC repeat-containing RNA in nuclear foci led to the suggestion that toxic gain of RNA function, perhaps related to sequestration of RNA-binding proteins, might be an important driver of disease. Third, it was subsequently appreciated that GGGGCC repeat-containing RNA undergoes unconventional translation to produce unnatural dipeptide repeat (DPR) proteins that accumulate in patient brain early in disease. DPRs translated from all six reading frames in either the sense or antisense direction of the hexanucleotide repeat result in the expression of five DPRs: glycine–alanine (GA), glycine–arginine (GR), proline–alanine (PA), proline–arginine (PR) and glycine–proline (GP; GP is generated from both the sense and antisense reading frames). However, the relative contribution of each DPR to disease pathogenesis remains unclear. Here, we review evidence for the contribution of each specific DPR to pathogenesis and examine the probable mechanisms through which these DPRs induce neurodegeneration. We also consider the association of the toxic DPRs with impaired RNA metabolism and alterations to the liquid-like state of non-membrane-bound organelles.
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Affiliation(s)
- Brian D Freibaum
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital Memphis, TN, USA
| | - J Paul Taylor
- Department of Cell and Molecular Biology, St. Jude Children's Research HospitalMemphis, TN, USA; Howard Hughes Medical InstituteChevy Chase, MD, USA
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