1
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Chong ZZ, Souayah N. Targeting Gene C9orf72 Pathogenesis for Amyotrophic Lateral Sclerosis. Int J Mol Sci 2025; 26:4276. [PMID: 40362512 PMCID: PMC12072292 DOI: 10.3390/ijms26094276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2025] [Revised: 04/23/2025] [Accepted: 04/28/2025] [Indexed: 05/15/2025] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal adult neurodegenerative disorder. Since no cure has been found, finding effective therapeutic targets for ALS remains a major challenge. Gene C9orf72 mutations with the formation of hexanucleotide repeat (GGGGCC) expansion (HRE) have been considered the most common genetic pathogenesis of ALS. The literature review indicates that the C9orf72 HRE causes both the gain-of-function toxicity and loss of function of C9ORF72. The formation of RNA foci and dipeptide repeats (DPRs) resulting from HRE is responsible for toxic function gain. The RNA foci can interfere with RNA processing, while DPRs directly bind to and sequester associated proteins to disrupt processes of rRNA synthesis, mRNA translation, autophagy, and nucleocytoplasmic transport. The mutations of C9orf72 and HRE result in the loss of functional C9ORF72. Under physiological conditions, C9ORF72 binds to Smith-Magenis chromosome region 8 and WD repeat-containing protein and forms a protein complex. Loss of C9ORF72 leads to autophagic impairment, increased oxidative stress, nucleocytoplasmic transport impairment, and inflammatory response. The attempted treatments for ALS have been tried by targeting C9orf72 HRE; however, the outcomes are far from satisfactory yet. More studies should be performed on pharmacological and molecular modulators against C9orf72 HRE to evaluate their efficacy by targeting HRE.
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Affiliation(s)
- Zhao Zhong Chong
- Department of Neurology, New Jersey Medical School, Rutgers University, 185 S Orange, Newark, NJ 07103, USA
| | - Nizar Souayah
- Department of Neurology, New Jersey Medical School, Rutgers University, 90 Bergen Street DOC 8100, Newark, NJ 07101, USA
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2
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Ban Z, Lin Y, Yan Y, Dawson KA. Unraveling biomolecular and community grammars of RNA granules via machine learning. PNAS NEXUS 2025; 4:pgaf093. [PMID: 40160533 PMCID: PMC11952899 DOI: 10.1093/pnasnexus/pgaf093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2024] [Accepted: 03/06/2025] [Indexed: 04/02/2025]
Abstract
Membraneless RNA granules are essential for posttranscriptional gene regulation, influencing cellular functions and contributing to neurodegenerative diseases. However, a comprehensive understanding of their compositions and organization has been challenging due to their complex nature. In this study, we develop robust machine learning models to reliably identify RNA granule proteomes within the human proteome, capturing central RNA granule characteristics despite the heterogeneity across diverse in vitro conditions. Furthermore, we uncover protein-protein interaction (PPI) community grammars within the RNA granule proteome, highlighting PPIs as key stabilizers of RNA granule structure and function. Dense PPI clusters serve as stable "cores," forming key functional subunits across heterogeneous RNA granules. We introduce a state-of-the-art framework for understanding RNA granule biology and underscore the critical role of PPIs in maintaining RNA granule integrity.
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Affiliation(s)
- Zhan Ban
- Centre for BioNano Interactions, School of Chemistry, University College Dublin, Dublin 4, D04 N2E5, Ireland
- School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, D04 N2E5, Ireland
| | - Yuchen Lin
- Centre for BioNano Interactions, School of Chemistry, University College Dublin, Dublin 4, D04 N2E5, Ireland
- School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, D04 N2E5, Ireland
| | - Yan Yan
- Centre for BioNano Interactions, School of Chemistry, University College Dublin, Dublin 4, D04 N2E5, Ireland
- School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, D04 N2E5, Ireland
| | - Kenneth A Dawson
- Centre for BioNano Interactions, School of Chemistry, University College Dublin, Dublin 4, D04 N2E5, Ireland
- School of Biomolecular and Biomedical Science, UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Dublin 4, D04 N2E5, Ireland
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3
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Webster CP, Hall B, Crossley OM, Dauletalina D, King M, Lin YH, Castelli LM, Yang ZL, Coldicott I, Kyrgiou-Balli E, Higginbottom A, Ferraiuolo L, De Vos KJ, Hautbergue GM, Shaw PJ, West RJ, Azzouz M. RuvBL1/2 reduce toxic dipeptide repeat protein burden in multiple models of C9orf72-ALS/FTD. Life Sci Alliance 2025; 8:e202402757. [PMID: 39638345 PMCID: PMC11629685 DOI: 10.26508/lsa.202402757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 11/22/2024] [Accepted: 11/25/2024] [Indexed: 12/07/2024] Open
Abstract
A G4C2 hexanucleotide repeat expansion in C9orf72 is the most common cause of amyotrophic lateral sclerosis and frontotemporal dementia (C9ALS/FTD). Bidirectional transcription and subsequent repeat-associated non-AUG (RAN) translation of sense and antisense transcripts leads to the formation of five dipeptide repeat (DPR) proteins. These DPRs are toxic in a wide range of cell and animal models. Therefore, decreasing RAN-DPRs may be of therapeutic benefit in the context of C9ALS/FTD. In this study, we found that C9ALS/FTD patients have reduced expression of the AAA+ family members RuvBL1 and RuvBL2, which have both been implicated in aggregate clearance. We report that overexpression of RuvBL1, but to a greater extent RuvBL2, reduced C9orf72-associated DPRs in a range of in vitro systems including cell lines, primary neurons from the C9-500 transgenic mouse model, and patient-derived iPSC motor neurons. In vivo, we further demonstrated that RuvBL2 overexpression and consequent DPR reduction in our Drosophila model was sufficient to rescue a number of DPR-related motor phenotypes. Thus, modulating RuvBL levels to reduce DPRs may be of therapeutic potential in C9ALS/FTD.
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Affiliation(s)
- Christopher P Webster
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Bradley Hall
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Olivia M Crossley
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Dana Dauletalina
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Marianne King
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Zih-Liang Yang
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Ian Coldicott
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Ergita Kyrgiou-Balli
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Adrian Higginbottom
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Laura Ferraiuolo
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Kurt J De Vos
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
- Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, UK
| | - Pamela J Shaw
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Ryan Jh West
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
| | - Mimoun Azzouz
- Sheffield Institute for Translational Neuroscience (SITraN), Division of Neuroscience, School of Medicine and Population Health, Faculty of Health, University of Sheffield, Sheffield, UK
- Neuroscience Institute, University of Sheffield, Sheffield, UK
- Gene Therapy Innovation and Manufacturing Centre (GTIMC), Division of Neuroscience, University of Sheffield, Sheffield, UK
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4
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Li Y, Sun S. RNA dysregulation in neurodegenerative diseases. EMBO J 2025; 44:613-638. [PMID: 39789319 PMCID: PMC11790913 DOI: 10.1038/s44318-024-00352-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2024] [Revised: 11/27/2024] [Accepted: 12/10/2024] [Indexed: 01/12/2025] Open
Abstract
Dysregulation of RNA processing has in recent years emerged as a significant contributor to neurodegeneration. The diverse mechanisms and molecular functions underlying RNA processing underscore the essential role of RNA regulation in maintaining neuronal health and function. RNA molecules are bound by RNA-binding proteins (RBPs), and interactions between RNAs and RBPs are commonly affected in neurodegeneration. In this review, we highlight recent progress in understanding dysregulated RNA-processing pathways and the causes of RBP dysfunction across various neurodegenerative diseases. We discuss both established and emerging mechanisms of RNA-mediated neuropathogenesis in this rapidly evolving field. Furthermore, we explore the development of potential RNA-targeting therapeutic approaches for the treatment of neurodegenerative diseases.
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Affiliation(s)
- Yini Li
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA
| | - Shuying Sun
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
- Departments of Neuroscience, Pathology, Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
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5
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Dong D, Zhang Z, Li Y, Latallo MJ, Wang S, Nelson B, Wu R, Krishnan G, Gao FB, Wu B, Sun S. Poly-GR repeats associated with ALS/FTD gene C9ORF72 impair translation elongation and induce a ribotoxic stress response in neurons. Sci Signal 2024; 17:eadl1030. [PMID: 39106320 PMCID: PMC11466505 DOI: 10.1126/scisignal.adl1030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 07/05/2024] [Indexed: 08/09/2024]
Abstract
Hexanucleotide repeat expansion in the C9ORF72 gene is the most frequent inherited cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). The expansion results in multiple dipeptide repeat proteins, among which arginine-rich poly-GR proteins are highly toxic to neurons and decrease the rate of protein synthesis. We investigated whether the effect on protein synthesis contributes to neuronal dysfunction and degeneration. We found that the expression of poly-GR proteins inhibited global translation by perturbing translation elongation. In iPSC-differentiated neurons, the translation of transcripts with relatively slow elongation rates was further slowed, and stalled, by poly-GR. Elongation stalling increased ribosome collisions and induced a ribotoxic stress response (RSR) mediated by ZAKα that increased the phosphorylation of the kinase p38 and promoted cell death. Knockdown of ZAKα or pharmacological inhibition of p38 ameliorated poly-GR-induced toxicity and improved the survival of iPSC-derived neurons from patients with C9ORF72-ALS/FTD. Our findings suggest that targeting the RSR may be neuroprotective in patients with ALS/FTD caused by repeat expansion in C9ORF72.
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Affiliation(s)
- Daoyuan Dong
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Zhe Zhang
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Yini Li
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Malgorzata J. Latallo
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Shaopeng Wang
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Blake Nelson
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Rong Wu
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
| | - Gopinath Krishnan
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA 01605, USA
| | - Bin Wu
- Department of Biophysics and Biophysical Chemistry, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shuying Sun
- Department of Physiology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Brain Science Institute, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Center for Cell Dynamics, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Pathology, Johns Hopkins University School of Medicine; Baltimore, MD 21205, USA
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6
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Park J, Desai H, Liboy-Lugo JM, Gu S, Jowhar Z, Xu A, Floor SN. IGHMBP2 deletion suppresses translation and activates the integrated stress response. Life Sci Alliance 2024; 7:e202302554. [PMID: 38803225 PMCID: PMC11109757 DOI: 10.26508/lsa.202302554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/01/2024] [Accepted: 05/02/2024] [Indexed: 05/29/2024] Open
Abstract
IGHMBP2 is a nonessential, superfamily 1 DNA/RNA helicase that is mutated in patients with rare neuromuscular diseases SMARD1 and CMT2S. IGHMBP2 is implicated in translational and transcriptional regulation via biochemical association with ribosomal proteins, pre-rRNA processing factors, and tRNA-related species. To uncover the cellular consequences of perturbing IGHMBP2, we generated full and partial IGHMBP2 deletion K562 cell lines. Using polysome profiling and a nascent protein synthesis assay, we found that IGHMBP2 deletion modestly reduces global translation. We performed Ribo-seq and RNA-seq and identified diverse gene expression changes due to IGHMBP2 deletion, including ATF4 up-regulation. With recent studies showing the integrated stress response (ISR) can contribute to tRNA metabolism-linked neuropathies, we asked whether perturbing IGHMBP2 promotes ISR activation. We generated ATF4 reporter cell lines and found IGHMBP2 knockout cells demonstrate basal, chronic ISR activation. Our work expands upon the impact of IGHMBP2 in translation and elucidates molecular mechanisms that may link mutant IGHMBP2 to severe clinical phenotypes.
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Affiliation(s)
- Jesslyn Park
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Hetvee Desai
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - José M Liboy-Lugo
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Sohyun Gu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
| | - Ziad Jowhar
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Albert Xu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, CA, USA
| | - Stephen N Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
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7
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Zambon AA, Falzone YM, Bolino A, Previtali SC. Molecular mechanisms and therapeutic strategies for neuromuscular diseases. Cell Mol Life Sci 2024; 81:198. [PMID: 38678519 PMCID: PMC11056344 DOI: 10.1007/s00018-024-05229-9] [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: 01/02/2024] [Revised: 03/14/2024] [Accepted: 04/07/2024] [Indexed: 05/01/2024]
Abstract
Neuromuscular diseases encompass a heterogeneous array of disorders characterized by varying onset ages, clinical presentations, severity, and progression. While these conditions can stem from acquired or inherited causes, this review specifically focuses on disorders arising from genetic abnormalities, excluding metabolic conditions. The pathogenic defect may primarily affect the anterior horn cells, the axonal or myelin component of peripheral nerves, the neuromuscular junction, or skeletal and/or cardiac muscles. While inherited neuromuscular disorders have been historically deemed not treatable, the advent of gene-based and molecular therapies is reshaping the treatment landscape for this group of condition. With the caveat that many products still fail to translate the positive results obtained in pre-clinical models to humans, both the technological development (e.g., implementation of tissue-specific vectors) as well as advances on the knowledge of pathogenetic mechanisms form a collective foundation for potentially curative approaches to these debilitating conditions. This review delineates the current panorama of therapies targeting the most prevalent forms of inherited neuromuscular diseases, emphasizing approved treatments and those already undergoing human testing, offering insights into the state-of-the-art interventions.
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Affiliation(s)
- Alberto Andrea Zambon
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Yuri Matteo Falzone
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy
| | - Alessandra Bolino
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy
- Vita-Salute San Raffaele University, Milan, Italy
| | - Stefano Carlo Previtali
- Division of Neuroscience, IRCCS San Raffaele Scientific Institute, Institute for Experimental Neurology, Inspe, Milan, Italy.
- Neurology Department, San Raffaele Scientific Institute, Milan, Italy.
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8
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Vadla GP, Singh K, Lorson CL, Lorson MA. The contribution and therapeutic implications of IGHMBP2 mutations on IGHMBP2 biochemical activity and ABT1 association. Biochim Biophys Acta Mol Basis Dis 2024; 1870:167091. [PMID: 38403020 PMCID: PMC10999323 DOI: 10.1016/j.bbadis.2024.167091] [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: 11/16/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/27/2024]
Abstract
Mutations within immunoglobulin mu DNA binding protein (IGHMBP2), an RNA-DNA helicase, result in SMA with respiratory distress type I (SMARD1) and Charcot Marie Tooth type 2S (CMT2S). The underlying biochemical mechanism of IGHMBP2 is unknown as well as the functional significance of IGHMBP2 mutations in disease severity. Here we report the biochemical mechanisms of IGHMBP2 disease-causing mutations D565N and H924Y, and their potential impact on therapeutic strategies. The IGHMBP2-D565N mutation has been identified in SMARD1 patients, while the IGHMBP2-H924Y mutation has been identified in CMT2S patients. For the first time, we demonstrate a correlation between the altered IGHMBP2 biochemical activity associated with the D565N and H924Y mutations and disease severity and pathology in patients and our Ighmbp2 mouse models. We show that IGHMBP2 mutations that alter the association with activator of basal transcription (ABT1) impact the ATPase and helicase activities of IGHMBP2 and the association with the 47S pre-rRNA 5' external transcribed spacer. We demonstrate that the D565N mutation impairs IGHMBP2 ATPase and helicase activities consistent with disease pathology. The H924Y mutation alters IGHMBP2 activity to a lesser extent while maintaining association with ABT1. In the context of the compound heterozygous patient, we demonstrate that the total biochemical activity associated with IGHMBP2-D565N and IGHMBP2-H924Y proteins is improved over IGHMBP2-D565N alone. Importantly, we demonstrate that the efficacy of therapeutic applications may vary based on the underlying IGHMBP2 mutations and the relative biochemical activity of the mutant IGHMBP2 protein.
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Affiliation(s)
- Gangadhar P Vadla
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Kamal Singh
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Monique A Lorson
- Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA; Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.
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9
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Zhou L, Xu R. Invertebrate genetic models of amyotrophic lateral sclerosis. Front Mol Neurosci 2024; 17:1328578. [PMID: 38500677 PMCID: PMC10944931 DOI: 10.3389/fnmol.2024.1328578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 01/24/2024] [Indexed: 03/20/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a common adult-onset neurodegenerative disease characterized by the progressive death of motor neurons in the cerebral cortex, brain stem, and spinal cord. The exact mechanisms underlying the pathogenesis of ALS remain unclear. The current consensus regarding the pathogenesis of ALS suggests that the interaction between genetic susceptibility and harmful environmental factors is a promising cause of ALS onset. The investigation of putative harmful environmental factors has been the subject of several ongoing studies, but the use of transgenic animal models to study ALS has provided valuable information on the onset of ALS. Here, we review the current common invertebrate genetic models used to study the pathology, pathophysiology, and pathogenesis of ALS. The considerations of the usage, advantages, disadvantages, costs, and availability of each invertebrate model will also be discussed.
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Affiliation(s)
- LiJun Zhou
- Department of Neurology, National Regional Center for Neurological Diseases, Clinical College of Nanchang Medical College, Jiangxi Provincial People's Hospital, First Affiliated Hospital of Nanchang Medical College, Xiangya Hospital of Central South University Jiangxi Hospital, Nanchang, Jiangxi, China
- Medical College of Nanchang University, Nanchang, China
| | - RenShi Xu
- Department of Neurology, National Regional Center for Neurological Diseases, Clinical College of Nanchang Medical College, Jiangxi Provincial People's Hospital, First Affiliated Hospital of Nanchang Medical College, Xiangya Hospital of Central South University Jiangxi Hospital, Nanchang, Jiangxi, China
- Medical College of Nanchang University, Nanchang, China
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10
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Cabrera GT, Meijboom KE, Abdallah A, Tran H, Foster Z, Weiss A, Wightman N, Stock R, Gendron T, Gruntman A, Giampetruzzi A, Petrucelli L, Brown RH, Mueller C. Artificial microRNA suppresses C9ORF72 variants and decreases toxic dipeptide repeat proteins in vivo. Gene Ther 2024; 31:105-118. [PMID: 37752346 DOI: 10.1038/s41434-023-00418-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 05/28/2023] [Accepted: 08/11/2023] [Indexed: 09/28/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that affects motor neurons, causing progressive muscle weakness and respiratory failure. The presence of an expanded hexanucleotide repeat in chromosome 9 open reading frame 72 (C9ORF72) is the most frequent mutation causing familial ALS and frontotemporal dementia (FTD). To determine if suppressing expression of C9ORF72 gene products can reduce toxicity, we designed a set of artificial microRNAs (amiRNA) targeting the human C9ORF72 gene. Here we report that an AAV9-mediated amiRNA significantly suppresses expression of the C9ORF72 mRNA, protein, and toxic dipeptide repeat proteins generated by the expanded repeat in the brain and spinal cord of C9ORF72 transgenic mice.
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Affiliation(s)
- Gabriela Toro Cabrera
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Katharina E Meijboom
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Abbas Abdallah
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Helene Tran
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Zachariah Foster
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Alexandra Weiss
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Nicholas Wightman
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Rachel Stock
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Tania Gendron
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL, 32224, USA
| | - Alisha Gruntman
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Anthony Giampetruzzi
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, 4500 San Pablo Rd., Jacksonville, FL, 32224, USA
| | - Robert H Brown
- Department of Neurology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA.
| | - Christian Mueller
- Department of Pediatrics and Gene Therapy Center, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA.
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11
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Gomez N, Hsieh C, Li X, Dykstra M, Waksmacki J, Altheim C, Bechar Y, Klim J, Zaepfel B, Rothstein J, Tank EE, Barmada SJ. Counter-regulation of RNA stability by UPF1 and TDP43. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.31.578310. [PMID: 38352350 PMCID: PMC10862862 DOI: 10.1101/2024.01.31.578310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/22/2024]
Abstract
RNA quality control is crucial for proper regulation of gene expression. Disruption of nonsense mediated mRNA decay (NMD), the primary RNA decay pathway responsible for the degradation of transcripts containing premature termination codons (PTCs), can disrupt development and lead to multiple diseases in humans and other animals. Similarly, therapies targeting NMD may have applications in hematological, neoplastic and neurological disorders. As such, tools capable of accurately quantifying NMD status could be invaluable for investigations of disease pathogenesis and biomarker identification. Toward this end, we assemble, validate, and apply a next-generation sequencing approach (NMDq) for identifying and measuring the abundance of PTC-containing transcripts. After validating NMDq performance and confirming its utility for tracking RNA surveillance, we apply it to determine pathway activity in two neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) characterized by RNA misprocessing and abnormal RNA stability. Despite the genetic and pathologic evidence implicating dysfunctional RNA metabolism, and NMD in particular, in these conditions, we detected no significant differences in PTC-encoding transcripts in ALS models or disease. Contrary to expectations, overexpression of the master NMD regulator UPF1 had little effect on the clearance of transcripts with PTCs, but rather restored RNA homeostasis through differential use and decay of alternatively poly-adenylated isoforms. Together, these data suggest that canonical NMD is not a significant contributor to ALS/FTD pathogenesis, and that UPF1 promotes neuronal survival by regulating transcripts with abnormally long 3'UTRs.
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12
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Chong ZZ, Menkes DL, Souayah N. Pathogenesis underlying hexanucleotide repeat expansions in C9orf72 gene in amyotrophic lateral sclerosis. Rev Neurosci 2024; 35:85-97. [PMID: 37525497 DOI: 10.1515/revneuro-2023-0060] [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: 05/29/2023] [Accepted: 07/07/2023] [Indexed: 08/02/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rapidly progressive and fatal neurodegenerative disorder. Mutations in C9orf72 and the resulting hexanucleotide repeat (GGGGCC) expansion (HRE) has been identified as a major cause of familial ALS, accounting for about 40 % of familial and 6 % of sporadic cases of ALS in Western patients. The pathological outcomes of HRE expansion in ALS have been recognized as the results of two mechanisms that include both the toxic gain-of-function and loss-of-function of C9ORF72. The gain of toxicity results from RNA and dipeptide repeats (DPRs). The HRE can be bidirectionally transcribed into RNA foci, which can bind to and disrupt RNA splicing, transport, and translation. The DPRs that include poly-glycine-alanine, poly-glycine-proline, poly-glycine- arginine, poly-proline-alanine, and poly-proline-arginine can induce toxicity by direct binding and sequestrating other proteins to interfere rRNA synthesis, ribosome biogenesis, translation, and nucleocytoplasmic transport. The C9ORF72 functions through binding to its partners-Smith-Magenis chromosome regions 8 (SMCR8) and WD repeat-containing protein (WDR41). Loss of C9ORF72 function results in impairment of autophagy, deregulation of autoimmunity, increased stress, and disruption of nucleocytoplasmic transport. Further insight into the mechanism in C9ORF72 HRE pathogenesis will facilitate identifying novel and effective therapeutic targets for ALS.
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Affiliation(s)
- Zhao Zhong Chong
- Department of Neurology, Rutgers University, New Jersey Medical School, 185 S. Orange Ave, Newark, NJ 07103, USA
| | - Daniel L Menkes
- Department of Neurology, Oakland University William Beaumont School of Medicine, 3555 West 13 Mile Road, Suite N120, Royal Oak, MI 48073, USA
| | - Nizar Souayah
- Department of Neurology, Rutgers University, New Jersey Medical School, 90 Bergen Street DOC 8100, Newark, NJ 07101, USA
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13
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Park JE, Desai H, Liboy-Lugo J, Gu S, Jowhar Z, Xu A, Floor SN. IGHMBP2 deletion suppresses translation and activates the integrated stress response. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.11.571166. [PMID: 38168189 PMCID: PMC10760061 DOI: 10.1101/2023.12.11.571166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
IGHMBP2 is a non-essential, superfamily 1 DNA/RNA helicase that is mutated in patients with rare neuromuscular diseases SMARD1 and CMT2S. IGHMBP2 is implicated in translational and transcriptional regulation via biochemical association with ribosomal proteins, pre-rRNA processing factors, and tRNA-related species. To uncover the cellular consequences of perturbing IGHMBP2, we generated full and partial IGHMBP2 deletion K562 cell lines. Using polysome profiling and a nascent protein synthesis assay, we found that IGHMBP2 deletion modestly reduces global translation. We performed Ribo-seq and RNA-seq and identified diverse gene expression changes due to IGHMBP2 deletion, including ATF4 upregulation. With recent studies showing the ISR can contribute to tRNA metabolism-linked neuropathies, we asked whether perturbing IGHMBP2 promotes ISR activation. We generated ATF4 reporter cell lines and found IGHMBP2 knockout cells demonstrate basal, chronic ISR activation. Our work expands upon the impact of IGHMBP2 in translation and elucidates molecular mechanisms that may link mutant IGHMBP2 to severe clinical phenotypes.
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Affiliation(s)
- Jesslyn E. Park
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Hetvee Desai
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
| | - José Liboy-Lugo
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Tetrad Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Sohyun Gu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Ziad Jowhar
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Albert Xu
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Biomedical Sciences Graduate Program, University of California, San Francisco, San Francisco, California, USA, 94143
| | - Stephen N. Floor
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, California, USA, 94143
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, California, USA, 94143
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14
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Yang S, Wijegunawardana D, Sheth U, Veire AM, Salgado JMS, Agrawal M, Zhou J, Pereira JD, Gendron TF, Guo JU. Aberrant splicing exonizes C9ORF72 repeat expansion in ALS/FTD. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.13.566896. [PMID: 38014069 PMCID: PMC10680656 DOI: 10.1101/2023.11.13.566896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
A nucleotide repeat expansion (NRE) in the first annotated intron of the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). While C9 NRE-containing RNAs can be translated into several toxic dipeptide repeat proteins, how an intronic NRE can assess the translation machinery in the cytoplasm remains unclear. By capturing and sequencing NRE-containing RNAs from patient-derived cells, we found that C9 NRE was exonized by the usage of downstream 5' splice sites and exported from the nucleus in a variety of spliced mRNA isoforms. C9ORF72 aberrant splicing was substantially elevated in both C9 NRE+ motor neurons and human brain tissues. Furthermore, NREs above the pathological threshold were sufficient to activate cryptic splice sites in reporter mRNAs. In summary, our results revealed a crucial and potentially widespread role of repeat-induced aberrant splicing in the biogenesis, localization, and translation of NRE-containing RNAs.
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Affiliation(s)
- Suzhou Yang
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Denethi Wijegunawardana
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Udit Sheth
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Austin M. Veire
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Juliana M. S. Salgado
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Manasi Agrawal
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Jeffrey Zhou
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - João D. Pereira
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Tania F. Gendron
- Neurobiology of Disease Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences; Jacksonville, FL 32224, USA
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Junjie U. Guo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
- Program in Cellular Neuroscience, Neurodegeneration, and Repair, Yale University School of Medicine, New Haven, CT 06520, USA
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15
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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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16
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Hwang HJ, Park TL, Kim HI, Park Y, Kim G, Song C, Cho WK, Kim YK. YTHDF2 facilitates aggresome formation via UPF1 in an m 6A-independent manner. Nat Commun 2023; 14:6248. [PMID: 37803021 PMCID: PMC10558514 DOI: 10.1038/s41467-023-42015-w] [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: 11/15/2022] [Accepted: 09/27/2023] [Indexed: 10/08/2023] Open
Abstract
YTHDF2 has been extensively studied and typified as an RNA-binding protein that specifically recognizes and destabilizes RNAs harboring N6-methyladenosine (m6A), the most prevalent internal modification found in eukaryotic RNAs. In this study, we unravel the m6A-independent role of YTHDF2 in the formation of an aggresome, where cytoplasmic protein aggregates are selectively sequestered upon failure of protein homeostasis mediated by the ubiquitin-proteasome system. Downregulation of YTHDF2 in HeLa cells reduces the circularity of aggresomes and the rate of movement of misfolded polypeptides, inhibits aggresome formation, and thereby promotes cellular apoptosis. Mechanistically, YTHDF2 is recruited to a misfolded polypeptide-associated complex composed of UPF1, CTIF, eEF1A1, and DCTN1 through its interaction with UPF1. Subsequently, YTHDF2 increases the interaction between the dynein motor protein and the misfolded polypeptide-associated complex, facilitating the diffusion dynamics of the movement of misfolded polypeptides toward aggresomes. Therefore, our data reveal that YTHDF2 is a cellular factor involved in protein quality control.
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Affiliation(s)
- Hyun Jung Hwang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Tae Lim Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Hyeong-In Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Yeonkyoung Park
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Geunhee Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Chiyeol Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea
| | - Won-Ki Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
| | - Yoon Ki Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, 34141, Republic of Korea.
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17
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Monaghan L, Longman D, Cáceres JF. Translation-coupled mRNA quality control mechanisms. EMBO J 2023; 42:e114378. [PMID: 37605642 PMCID: PMC10548175 DOI: 10.15252/embj.2023114378] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023] Open
Abstract
mRNA surveillance pathways are essential for accurate gene expression and to maintain translation homeostasis, ensuring the production of fully functional proteins. Future insights into mRNA quality control pathways will enable us to understand how cellular mRNA levels are controlled, how defective or unwanted mRNAs can be eliminated, and how dysregulation of these can contribute to human disease. Here we review translation-coupled mRNA quality control mechanisms, including the non-stop and no-go mRNA decay pathways, describing their mechanisms, shared trans-acting factors, and differences. We also describe advances in our understanding of the nonsense-mediated mRNA decay (NMD) pathway, highlighting recent mechanistic findings, the discovery of novel factors, as well as the role of NMD in cellular physiology and its impact on human disease.
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Affiliation(s)
- Laura Monaghan
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Dasa Longman
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
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18
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Petrić Howe M, Patani R. Nonsense-mediated mRNA decay in neuronal physiology and neurodegeneration. Trends Neurosci 2023; 46:879-892. [PMID: 37543480 DOI: 10.1016/j.tins.2023.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/19/2023] [Accepted: 07/09/2023] [Indexed: 08/07/2023]
Abstract
The processes of mRNA export from the nucleus and subsequent mRNA translation in the cytoplasm are of particular relevance in eukaryotic cells. In highly polarised cells such as neurons, finely-tuned molecular regulation of these processes serves to safeguard the spatiotemporal fidelity of gene expression. Nonsense-mediated mRNA decay (NMD) is a cytoplasmic translation-dependent quality control process that regulates gene expression in a wide range of scenarios in the nervous system, including neurodevelopment, learning, and memory formation. Moreover, NMD dysregulation has been implicated in a broad range of neurodevelopmental and neurodegenerative disorders. We discuss how NMD and related aspects of mRNA translation regulate key neuronal functions and, in particular, we focus on evidence implicating these processes in the molecular pathogenesis of neurodegeneration. Finally, we discuss the therapeutic potential and challenges of targeting mRNA translation and NMD across the spectrum of largely untreatable neurological diseases.
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Affiliation(s)
- Marija Petrić Howe
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London (UCL), Queen Square, WC1N 3BG London, UK.
| | - Rickie Patani
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London (UCL), Queen Square, WC1N 3BG London, UK.
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19
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Bohnsack KE, Yi S, Venus S, Jankowsky E, Bohnsack MT. Cellular functions of eukaryotic RNA helicases and their links to human diseases. Nat Rev Mol Cell Biol 2023; 24:749-769. [PMID: 37474727 DOI: 10.1038/s41580-023-00628-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2023] [Indexed: 07/22/2023]
Abstract
RNA helicases are highly conserved proteins that use nucleoside triphosphates to bind or remodel RNA, RNA-protein complexes or both. RNA helicases are classified into the DEAD-box, DEAH/RHA, Ski2-like, Upf1-like and RIG-I families, and are the largest class of enzymes active in eukaryotic RNA metabolism - virtually all aspects of gene expression and its regulation involve RNA helicases. Mutation and dysregulation of these enzymes have been linked to a multitude of diseases, including cancer and neurological disorders. In this Review, we discuss the regulation and functional mechanisms of RNA helicases and their roles in eukaryotic RNA metabolism, including in transcription regulation, pre-mRNA splicing, ribosome assembly, translation and RNA decay. We highlight intriguing models that link helicase structure, mechanisms of function (such as local strand unwinding, translocation, winching, RNA clamping and displacing RNA-binding proteins) and biological roles, including emerging connections between RNA helicases and cellular condensates formed through liquid-liquid phase separation. We also discuss associations of RNA helicases with human diseases and recent efforts towards the design of small-molecule inhibitors of these pivotal regulators of eukaryotic gene expression.
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Affiliation(s)
- Katherine E Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
| | - Soon Yi
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Sarah Venus
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Department of Biochemistry, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Case Comprehensive Cancer Center, School of Medicine, Case Western Reserve University, Cleveland, OH, USA.
- Moderna, Cambridge, MA, USA.
| | - Markus T Bohnsack
- Department of Molecular Biology, University Medical Center Göttingen, Göttingen, Germany.
- Göttingen Centre for Molecular Biosciences, University of Göttingen, Göttingen, Germany.
- Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany.
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20
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Held A, Adler M, Marques C, Reyes CJ, Kavuturu AS, Quadros ARAA, Ndayambaje IS, Lara E, Ward M, Lagier-Tourenne C, Wainger BJ. iPSC motor neurons, but not other derived cell types, capture gene expression changes in postmortem sporadic ALS motor neurons. Cell Rep 2023; 42:113046. [PMID: 37651231 PMCID: PMC10622181 DOI: 10.1016/j.celrep.2023.113046] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/10/2023] [Accepted: 08/11/2023] [Indexed: 09/02/2023] Open
Abstract
Motor neuron degeneration, the defining feature of amyotrophic lateral sclerosis (ALS), is a primary example of cell-type specificity in neurodegenerative diseases. Using isogenic pairs of induced pluripotent stem cells (iPSCs) harboring different familial ALS mutations, we assess the capacity of iPSC-derived lower motor neurons, sensory neurons, astrocytes, and superficial cortical neurons to capture disease features including transcriptional and splicing dysregulation observed in human postmortem neurons. At early time points, differentially regulated genes in iPSC-derived lower motor neurons, but not other cell types, overlap with one-third of the differentially regulated genes in laser-dissected motor neurons from ALS compared with control postmortem spinal cords. For genes altered in both the iPSC model and bona fide human lower motor neurons, expression changes correlate between the two populations. In iPSC-derived lower motor neurons, but not other derived cell types, we detect the downregulation of genes affected by TDP-43-dependent splicing. This reduction takes place exclusively within genotypes known to involve TDP-43 pathology.
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Affiliation(s)
- Aaron Held
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Michelle Adler
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Christine Marques
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Charles Jourdan Reyes
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; The Collaborative Center for X-Linked Dystonia-Parkinsonism, Department of Neurology, Massachusetts General Hospital, Charlestown, MA 02129, USA
| | - Amey S Kavuturu
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Ana R A A Quadros
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - I Sandra Ndayambaje
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Erika Lara
- iPSC Neurodegenerative Research Initiative, Center for Alzheimer's and Related Dementias, National Institute on Aging, NIH, Bethesda, MD 20892, USA
| | - Michael Ward
- National Institute of Neurological Disorders and Stroke, NIH, Bethesda, MD 20892, USA
| | - Clotilde Lagier-Tourenne
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard University and MIT, Cambridge MA 02142, USA
| | - Brian J Wainger
- Department of Neurology, Sean M. Healey & AMG Center for ALS, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Broad Institute of Harvard University and MIT, Cambridge MA 02142, USA; Department of Anesthesiology, Critical Care and Pain Medicine, Massachusetts General Hospital, Boston MA 02114, USA; Harvard Stem Cell Institute, Cambridge MA 02138, USA.
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21
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Viera Ortiz AP, Cajka G, Olatunji OA, Mikytuck B, Shalem O, Lee EB. Impaired ribosome-associated quality control of C9orf72 arginine-rich dipeptide-repeat proteins. Brain 2023; 146:2897-2912. [PMID: 36516294 PMCID: PMC10316761 DOI: 10.1093/brain/awac479] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 11/05/2022] [Accepted: 12/06/2022] [Indexed: 12/15/2022] Open
Abstract
Protein quality control pathways have evolved to ensure the fidelity of protein synthesis and efficiently clear potentially toxic protein species. Defects in ribosome-associated quality control and its associated factors have been implicated in the accumulation of aberrant proteins and neurodegeneration. C9orf72 repeat-associated non-AUG translation has been suggested to involve inefficient translation elongation, lead to ribosomal pausing and activation of ribosome-associated quality control pathways. However, the role of the ribosome-associated quality control complex in the processing of proteins generated through this non-canonical translation is not well understood. Here we use reporter constructs containing the C9orf72-associated hexanucleotide repeat, ribosome-associated quality control complex deficient cell models and stain for ribosome-associated quality control markers in C9orf72-expansion carrier human tissue to understand its role in dipeptide-repeat protein pathology. Our studies show that canonical ribosome-associated quality control substrates products are efficiently cleared by the ribosome-associated quality control complex in mammalian cells. Furthermore, using stalling reporter constructs, we show that repeats associated with the C9orf72-expansion induce ribosomal stalling when arginine (R)-rich dipeptide-repeat proteins are synthesized in a length-dependent manner. However, despite triggering this pathway, these arginine-rich dipeptide-repeat proteins are not efficiently processed by the core components of the ribosome-associated quality control complex (listerin, nuclear-export mediator factor and valosin containing protein) partly due to lack of lysine residues, which precludes ubiquitination. Deficient processing by this complex may be implicated in C9orf72-expansion associated disease as dipeptide-repeat protein inclusions were observed to be predominantly devoid of ubiquitin and co-localize with nuclear-export mediator factor in mutation carriers' frontal cortex and cerebellum tissue. These findings suggest that impaired processing of these arginine-rich dipeptide-repeat proteins derived from repeat-associated non-AUG translation by the ribosome-associated quality control complex may contribute to protein homeostasis dysregulation observed in C9orf72-expansion amyotrophic lateral sclerosis and frontotemporal degeneration neuropathogenesis.
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Affiliation(s)
- Ashley P Viera Ortiz
- Biochemistry and Molecular Biophysics Graduate Group, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gregory Cajka
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Olamide A Olatunji
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Bailey Mikytuck
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ophir Shalem
- Center for Cellular and Molecular Therapeutics, Children’s Hospital of Philadelphia, Philadelphia, PA 19104, USA
- Department of Genetics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Edward B Lee
- Translational Neuropathology Research Laboratory, Department of Pathology and Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
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22
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Kesner JS, Chen Z, Shi P, Aparicio AO, Murphy MR, Guo Y, Trehan A, Lipponen JE, Recinos Y, Myeku N, Wu X. Noncoding translation mitigation. Nature 2023; 617:395-402. [PMID: 37046090 PMCID: PMC10560126 DOI: 10.1038/s41586-023-05946-4] [Citation(s) in RCA: 47] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 03/13/2023] [Indexed: 04/14/2023]
Abstract
Translation is pervasive outside of canonical coding regions, occurring in long noncoding RNAs, canonical untranslated regions and introns1-4, especially in ageing4-6, neurodegeneration5,7 and cancer8-10. Notably, the majority of tumour-specific antigens are results of noncoding translation11-13. Although the resulting polypeptides are often nonfunctional, translation of noncoding regions is nonetheless necessary for the birth of new coding sequences14,15. The mechanisms underlying the surveillance of translation in diverse noncoding regions and how escaped polypeptides evolve new functions remain unclear10,16-19. Functional polypeptides derived from annotated noncoding sequences often localize to membranes20,21. Here we integrate massively parallel analyses of more than 10,000 human genomic sequences and millions of random sequences with genome-wide CRISPR screens, accompanied by in-depth genetic and biochemical characterizations. Our results show that the intrinsic nucleotide bias in the noncoding genome and in the genetic code frequently results in polypeptides with a hydrophobic C-terminal tail, which is captured by the ribosome-associated BAG6 membrane protein triage complex for either proteasomal degradation or membrane targeting. By contrast, canonical proteins have evolved to deplete C-terminal hydrophobic residues. Our results reveal a fail-safe mechanism for the surveillance of unwanted translation from diverse noncoding regions and suggest a possible biochemical route for the preferential membrane localization of newly evolved proteins.
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Affiliation(s)
- Jordan S Kesner
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Ziheng Chen
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Peiguo Shi
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Alexis O Aparicio
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Michael R Murphy
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yang Guo
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Aditi Trehan
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Jessica E Lipponen
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Yocelyn Recinos
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Natura Myeku
- Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Xuebing Wu
- Cardiometabolic Genomics Program, Division of Cardiology, Department of Medicine, Columbia University Irving Medical Center, New York, NY, USA.
- Department of Systems Biology, Columbia University Irving Medical Center, New York, NY, USA.
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23
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Phenotype and management of neurologic intronic repeat disorders (NIRDs). Rev Neurol (Paris) 2023; 179:173-182. [PMID: 36371266 DOI: 10.1016/j.neurol.2022.09.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/15/2022] [Accepted: 09/20/2022] [Indexed: 11/11/2022]
Abstract
During recent years an increasing number of neurologic disorders due to expanded tri-, tetra-, penta-, or hexa-nucleotide repeat motifs in introns of various genes have been described (neurologic intronic repeat disorders (NIRDs)). The repeat may be pathogenic in the heterozygous or homozygous form. Repeat lengths vary considerably and can be stable or unstable during transmission to the next generation. The most well-known NIRDs are Friedreich ataxia, spinocerebellar ataxia types-10, -31, and -36, CANVAS, C9Orf72 familial amyotrophic lateral sclerosis (fALS), and myotonic dystrophy-2 (MD2). Phenotypically, NIRDs manifest as mono-organ (e.g. spinocerebellar ataxia type 31) or multi-organ disease (e.g. Friedreich ataxia, myotonic dystrophy-2). A number of other more rare NIRDs have been recently detected. This review aims at summarising and discussing previous findings and recent advances concerning the etiology, pathophysiology, clinical presentation, and therapeutic management of the most common NIRDs.
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24
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McMillan M, Gomez N, Hsieh C, Bekier M, Li X, Miguez R, Tank EMH, Barmada SJ. RNA methylation influences TDP43 binding and disease pathogenesis in models of amyotrophic lateral sclerosis and frontotemporal dementia. Mol Cell 2023; 83:219-236.e7. [PMID: 36634675 PMCID: PMC9899051 DOI: 10.1016/j.molcel.2022.12.019] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/14/2022] [Accepted: 12/16/2022] [Indexed: 01/13/2023]
Abstract
RNA methylation at adenosine N6 (m6A) is one of the most common RNA modifications, impacting RNA stability, transport, and translation. Previous studies uncovered RNA destabilization in amyotrophic lateral sclerosis (ALS) models in association with accumulation of the RNA-binding protein TDP43. Here, we show that TDP43 recognizes m6A RNA and that RNA methylation is critical for both TDP43 binding and autoregulation. We also observed extensive RNA hypermethylation in ALS spinal cord, corresponding to methylated TDP43 substrates. Emphasizing the importance of m6A for TDP43 binding and function, we identified several m6A factors that enhance or suppress TDP43-mediated toxicity via single-cell CRISPR-Cas9 in primary neurons. The most promising modifier-the canonical m6A reader YTHDF2-accumulated within ALS spinal neurons, and its knockdown prolonged the survival of human neurons carrying ALS-associated mutations. Collectively, these data show that m6A modifications modulate RNA binding by TDP43 and that m6A is pivotal for TDP43-related neurodegeneration in ALS.
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Affiliation(s)
- Michael McMillan
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nicolas Gomez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA; Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Caroline Hsieh
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Michael Bekier
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Xingli Li
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Roberto Miguez
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Elizabeth M H Tank
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Sami J Barmada
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA; Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, MI 48109, USA.
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25
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Isiktas AU, Eshov A, Yang S, Guo JU. Systematic generation and imaging of tandem repeats reveal base-pairing properties that promote RNA aggregation. CELL REPORTS METHODS 2022; 2:100334. [PMID: 36452875 PMCID: PMC9701603 DOI: 10.1016/j.crmeth.2022.100334] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Revised: 09/19/2022] [Accepted: 10/18/2022] [Indexed: 11/10/2022]
Abstract
A common pathological feature of RNAs containing expanded repeat sequences is their propensity to aggregate in cells. While some repeat RNA aggregates have been shown to cause toxicity by sequestering RNA-binding proteins, the molecular mechanism of aggregation remains unclear. Here, we devised an efficient method to generate long tandem repeat DNAs de novo and applied it to systematically determine the sequence features underlying RNA aggregation. Live-cell imaging of repeat RNAs indicated that aggregation was promoted by multivalent RNA-RNA interactions via either canonical or noncanonical base pairs. While multiple runs of two consecutive base pairs were sufficient, longer runs of base pairs such as those formed by GGGGCC hexanucleotide repeats further enhanced aggregation. In summary, our study provides a unifying model for the molecular basis of repeat RNA aggregation and a generalizable approach for identifying the sequence and structural determinants underlying the distinct properties of repeat DNAs and RNAs.
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Affiliation(s)
- Atagun U. Isiktas
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Aziz Eshov
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Suzhou Yang
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Junjie U. Guo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
- Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
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26
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Meijboom KE, Abdallah A, Fordham NP, Nagase H, Rodriguez T, Kraus C, Gendron TF, Krishnan G, Esanov R, Andrade NS, Rybin MJ, Ramic M, Stephens ZD, Edraki A, Blackwood MT, Kahriman A, Henninger N, Kocher JPA, Benatar M, Brodsky MH, Petrucelli L, Gao FB, Sontheimer EJ, Brown RH, Zeier Z, Mueller C. CRISPR/Cas9-mediated excision of ALS/FTD-causing hexanucleotide repeat expansion in C9ORF72 rescues major disease mechanisms in vivo and in vitro. Nat Commun 2022; 13:6286. [PMID: 36271076 PMCID: PMC9587249 DOI: 10.1038/s41467-022-33332-7] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 09/13/2022] [Indexed: 12/25/2022] Open
Abstract
A GGGGCC24+ hexanucleotide repeat expansion (HRE) in the C9ORF72 gene is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), fatal neurodegenerative diseases with no cure or approved treatments that substantially slow disease progression or extend survival. Mechanistic underpinnings of neuronal death include C9ORF72 haploinsufficiency, sequestration of RNA-binding proteins in the nucleus, and production of dipeptide repeat proteins. Here, we used an adeno-associated viral vector system to deliver CRISPR/Cas9 gene-editing machineries to effectuate the removal of the HRE from the C9ORF72 genomic locus. We demonstrate successful excision of the HRE in primary cortical neurons and brains of three mouse models containing the expansion (500-600 repeats) as well as in patient-derived iPSC motor neurons and brain organoids (450 repeats). This resulted in a reduction of RNA foci, poly-dipeptides and haploinsufficiency, major hallmarks of C9-ALS/FTD, making this a promising therapeutic approach to these diseases.
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Affiliation(s)
- Katharina E. Meijboom
- grid.168645.80000 0001 0742 0364Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605 USA ,grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Abbas Abdallah
- grid.168645.80000 0001 0742 0364Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Nicholas P. Fordham
- grid.168645.80000 0001 0742 0364Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Hiroko Nagase
- grid.168645.80000 0001 0742 0364Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Tomás Rodriguez
- grid.168645.80000 0001 0742 0364RNA Therapeutics Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Carolyn Kraus
- grid.168645.80000 0001 0742 0364RNA Therapeutics Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Tania F. Gendron
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Gopinath Krishnan
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Rustam Esanov
- grid.26790.3a0000 0004 1936 8606Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Nadja S. Andrade
- grid.26790.3a0000 0004 1936 8606Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Matthew J. Rybin
- grid.26790.3a0000 0004 1936 8606Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Melina Ramic
- grid.26790.3a0000 0004 1936 8606Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Zachary D. Stephens
- grid.66875.3a0000 0004 0459 167XDepartment of Quantitative Health Sciences. Mayo Clinic, Rochester, MN 55905 USA
| | - Alireza Edraki
- grid.168645.80000 0001 0742 0364RNA Therapeutics Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Meghan T. Blackwood
- grid.168645.80000 0001 0742 0364Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Aydan Kahriman
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Nils Henninger
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Jean-Pierre A. Kocher
- grid.66875.3a0000 0004 0459 167XDepartment of Quantitative Health Sciences. Mayo Clinic, Rochester, MN 55905 USA
| | - Michael Benatar
- grid.26790.3a0000 0004 1936 8606Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136 USA
| | - Michael H. Brodsky
- grid.168645.80000 0001 0742 0364Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Leonard Petrucelli
- grid.417467.70000 0004 0443 9942Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224 USA
| | - Fen-Biao Gao
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Erik J. Sontheimer
- grid.168645.80000 0001 0742 0364RNA Therapeutics Institute and Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Robert H. Brown
- grid.168645.80000 0001 0742 0364Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605 USA
| | - Zane Zeier
- Department of Psychiatry & Behavioral Sciences, Center for Therapeutic Innovation, University of Miami Miller School of Medicine, Miami, FL, 33136, USA.
| | - Christian Mueller
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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27
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Miedema SSM, Mol MO, Koopmans FTW, Hondius DC, van Nierop P, Menden K, de Veij Mestdagh CF, van Rooij J, Ganz AB, Paliukhovich I, Melhem S, Li KW, Holstege H, Rizzu P, van Kesteren RE, van Swieten JC, Heutink P, Smit AB. Distinct cell type-specific protein signatures in GRN and MAPT genetic subtypes of frontotemporal dementia. Acta Neuropathol Commun 2022; 10:100. [PMID: 35799292 PMCID: PMC9261008 DOI: 10.1186/s40478-022-01387-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/22/2022] [Indexed: 11/16/2022] Open
Abstract
Frontotemporal dementia is characterized by progressive atrophy of frontal and/or temporal cortices at an early age of onset. The disorder shows considerable clinical, pathological, and genetic heterogeneity. Here we investigated the proteomic signatures of frontal and temporal cortex from brains with frontotemporal dementia due to GRN and MAPT mutations to identify the key cell types and molecular pathways in their pathophysiology. We compared patients with mutations in the GRN gene (n = 9) or with mutations in the MAPT gene (n = 13) with non-demented controls (n = 11). Using quantitative proteomic analysis on laser-dissected tissues we identified brain region-specific protein signatures for both genetic subtypes. Using published single cell RNA expression data resources we deduced the involvement of major brain cell types in driving these different protein signatures. Subsequent gene ontology analysis identified distinct genetic subtype- and cell type-specific biological processes. For the GRN subtype, we observed a distinct role for immune processes related to endothelial cells and for mitochondrial dysregulation in neurons. For the MAPT subtype, we observed distinct involvement of dysregulated RNA processing, oligodendrocyte dysfunction, and axonal impairments. Comparison with an in-house protein signature of Alzheimer’s disease brains indicated that the observed alterations in RNA processing and oligodendrocyte function are distinct for the frontotemporal dementia MAPT subtype. Taken together, our results indicate the involvement of different brain cell types and biological mechanisms in genetic subtypes of frontotemporal dementia. Furthermore, we demonstrate that comparison of proteomic profiles of different disease entities can separate general neurodegenerative processes from disease-specific pathways, which may aid the development of disease subtype-specific treatment strategies.
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Affiliation(s)
- Suzanne S M Miedema
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands.
| | - Merel O Mol
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Frank T W Koopmans
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - David C Hondius
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - Pim van Nierop
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - Kevin Menden
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany
| | - Christina F de Veij Mestdagh
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands.,Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, Groningen, the Netherlands.,Alzheimer Center, Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Jeroen van Rooij
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Andrea B Ganz
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands.,Alzheimer Center, Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Iryna Paliukhovich
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - Shamiram Melhem
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Ka Wan Li
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - Henne Holstege
- Alzheimer Center, Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands.,Department of Clinical Genetics, Amsterdam Neuroscience, VU University Medical Center, Amsterdam, The Netherlands
| | - Patrizia Rizzu
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany
| | - Ronald E van Kesteren
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
| | - John C van Swieten
- Department of Neurology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Clinical Genetics, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Peter Heutink
- German Center for Neurodegenerative Diseases (DZNE)-Tübingen, Tübingen, Germany
| | - August B Smit
- Department of Molecular and Cellular Neurobiology, Center for Neurogenomics and Cognitive Research, Amsterdam Neuroscience, Vrije Universiteit Amsterdam, W&N Building, C314. De Boelelaan 1105, 1081 HV, Amsterdam, The Netherlands
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28
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Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating motor neuron disease for which there is currently no robust therapy. Recent progress in understanding ALS disease mechanisms and genetics in combination with innovations in gene modulation strategies creates promising new options for the development of ALS therapies. In recent years, six gene modulation therapies have been tested in ALS patients. These target gain-of-function pathology of the most common ALS genes, SOD1, C9ORF72, FUS, and ATXN2, using adeno-associated virus (AAV)-mediated microRNAs and antisense oligonucleotides (ASOs). Here, we review the latest clinical and preclinical advances in gene modulation approaches for ALS, including gene silencing, gene correction, and gene augmentation. These techniques have the potential to positively impact the direction of future research trials and transform ALS treatments for this grave disease.
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Affiliation(s)
- Katharina E Meijboom
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA
| | - Robert H Brown
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA, 01605, USA.
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29
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Johnson MA, Nuckols TA, Merino P, Bagchi P, Nandy S, Root J, Taylor G, Seyfried NT, Kukar T. Proximity-based labeling reveals DNA damage-induced phosphorylation of fused in sarcoma (FUS) causes distinct changes in the FUS protein interactome. J Biol Chem 2022; 298:102135. [PMID: 35709984 PMCID: PMC9372748 DOI: 10.1016/j.jbc.2022.102135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Revised: 05/13/2022] [Accepted: 05/14/2022] [Indexed: 01/18/2023] Open
Abstract
Accumulation of cytoplasmic inclusions containing fused in sarcoma (FUS), an RNA/DNA-binding protein, is a common hallmark of frontotemporal lobar degeneration and amyotrophic lateral sclerosis neuropathology. We have previously shown that DNA damage can trigger the cytoplasmic accumulation of N-terminally phosphorylated FUS. However, the functional consequences of N-terminal FUS phosphorylation are unknown. To gain insight into this question, we utilized proximity-dependent biotin labeling via ascorbate peroxidase 2 aired with mass spectrometry to investigate whether N-terminal phosphorylation alters the FUS protein-protein interaction network (interactome), and subsequently, FUS function. We report the first analysis comparing the interactomes of three FUS variants: homeostatic wildtype FUS (FUS WT), phosphomimetic FUS (FUS PM; a proxy for N-terminally phosphorylated FUS), and the toxic FUS proline 525 to leucine mutant (FUS P525L) that causes juvenile amyotrophic lateral sclerosis. We found that the phosphomimetic FUS interactome is uniquely enriched for a group of cytoplasmic proteins that mediate mRNA metabolism and translation, as well as nuclear proteins involved in the spliceosome and DNA repair functions. Furthermore, we identified and validated the RNA-induced silencing complex RNA helicase MOV10 as a novel interacting partner of FUS. Finally, we provide functional evidence that N-terminally phosphorylated FUS may disrupt homeostatic translation and steady-state levels of specific mRNA transcripts. Taken together, these results highlight phosphorylation as a unique modulator of the interactome and function of FUS.
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Affiliation(s)
- Michelle A. Johnson
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Thomas A. Nuckols
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Paola Merino
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Pritha Bagchi
- Emory Integrated Proteomics Core, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Srijita Nandy
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Jessica Root
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Georgia Taylor
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Nicholas T. Seyfried
- Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA,Emory Integrated Proteomics Core, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Neurology, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Biochemistry, Emory University, School of Medicine, Atlanta, Georgia, USA
| | - Thomas Kukar
- Department of Pharmacology and Chemical Biology, Emory University, School of Medicine, Atlanta, Georgia, USA,Center for Neurodegenerative Disease, Emory University, School of Medicine, Atlanta, Georgia, USA,Department of Neurology, Emory University, School of Medicine, Atlanta, Georgia, USA,For correspondence: Thomas Kukar
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30
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Castelli LM, Benson BC, Huang WP, Lin YH, Hautbergue GM. RNA Helicases in Microsatellite Repeat Expansion Disorders and Neurodegeneration. Front Genet 2022; 13:886563. [PMID: 35646086 PMCID: PMC9133428 DOI: 10.3389/fgene.2022.886563] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 04/25/2022] [Indexed: 11/17/2022] Open
Abstract
Short repeated sequences of 3-6 nucleotides are causing a growing number of over 50 microsatellite expansion disorders, which mainly present with neurodegenerative features. Although considered rare diseases in relation to the relatively low number of cases, these primarily adult-onset conditions, often debilitating and fatal in absence of a cure, collectively pose a large burden on healthcare systems in an ageing world population. The pathological mechanisms driving disease onset are complex implicating several non-exclusive mechanisms of neuronal injury linked to RNA and protein toxic gain- and loss- of functions. Adding to the complexity of pathogenesis, microsatellite repeat expansions are polymorphic and found in coding as well as in non-coding regions of genes. They form secondary and tertiary structures involving G-quadruplexes and atypical helices in repeated GC-rich sequences. Unwinding of these structures by RNA helicases plays multiple roles in the expression of genes including repeat-associated non-AUG (RAN) translation of polymeric-repeat proteins with aggregating and cytotoxic properties. Here, we will briefly review the pathogenic mechanisms mediated by microsatellite repeat expansions prior to focus on the RNA helicases eIF4A, DDX3X and DHX36 which act as modifiers of RAN translation in C9ORF72-linked amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72-ALS/FTD) and Fragile X-associated tremor/ataxia syndrome (FXTAS). We will further review the RNA helicases DDX5/17, DHX9, Dicer and UPF1 which play additional roles in the dysregulation of RNA metabolism in repeat expansion disorders. In addition, we will contrast these with the roles of other RNA helicases such as DDX19/20, senataxin and others which have been associated with neurodegeneration independently of microsatellite repeat expansions. Finally, we will discuss the challenges and potential opportunities that are associated with the targeting of RNA helicases for the development of future therapeutic approaches.
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Affiliation(s)
- Lydia M Castelli
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Bridget C Benson
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Wan-Ping Huang
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Ya-Hui Lin
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom
| | - Guillaume M Hautbergue
- Sheffield Institute for Translational Neuroscience (SITraN), Department of Neuroscience, University of Sheffield, Sheffield, United Kingdom.,Neuroscience Institute, University of Sheffield, Sheffield, United Kingdom.,Healthy Lifespan Institute (HELSI), University of Sheffield, Sheffield, United Kingdom
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31
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Schröder C, Horsthemke B, Depienne C. GC-rich repeat expansions: associated disorders and mechanisms. MED GENET-BERLIN 2021; 33:325-335. [PMID: 38835438 PMCID: PMC11006399 DOI: 10.1515/medgen-2021-2099] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 11/12/2021] [Indexed: 06/06/2024]
Abstract
Noncoding repeat expansions are a well-known cause of genetic disorders mainly affecting the central nervous system. Missed by most standard technologies used in routine diagnosis, pathogenic noncoding repeat expansions have to be searched for using specific techniques such as repeat-primed PCR or specific bioinformatics tools applied to genome data, such as ExpansionHunter. In this review, we focus on GC-rich repeat expansions, which represent at least one third of all noncoding repeat expansions described so far. GC-rich expansions are mainly located in regulatory regions (promoter, 5' untranslated region, first intron) of genes and can lead to either a toxic gain-of-function mediated by RNA toxicity and/or repeat-associated non-AUG (RAN) translation, or a loss-of-function of the associated gene, depending on their size and their methylation status. We herein review the clinical and molecular characteristics of disorders associated with these difficult-to-detect expansions.
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Affiliation(s)
- Christopher Schröder
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Bernhard Horsthemke
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
| | - Christel Depienne
- Institute of Human Genetics, University Hospital Essen, University of Duisburg-Essen, Essen, Germany
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32
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Rossi S, Cozzolino M. Dysfunction of RNA/RNA-Binding Proteins in ALS Astrocytes and Microglia. Cells 2021; 10:cells10113005. [PMID: 34831228 PMCID: PMC8616248 DOI: 10.3390/cells10113005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2021] [Revised: 10/30/2021] [Accepted: 11/02/2021] [Indexed: 12/24/2022] Open
Abstract
Amyotrophic Lateral Sclerosis is a neurological disease that primarily affects motor neurons in the cortex, brainstem, and spinal cord. The process that leads to motor neuron degeneration is strongly influenced by non-motor neuronal events that occur in a variety of cell types. Among these, neuroinflammatory processes mediated by activated astrocytes and microglia play a relevant role. In recent years, it has become clear that dysregulation of essential steps of RNA metabolism, as a consequence of alterations in RNA-binding proteins (RBPs), is a central event in the degeneration of motor neurons. Yet, a causal link between dysfunctional RNA metabolism and the neuroinflammatory processes mediated by astrocytes and microglia in ALS has been poorly defined. In this review, we will discuss the available evidence showing that RBPs and associated RNA processing are affected in ALS astrocytes and microglia, and the possible mechanisms involved in these events.
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33
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Usluer S, Spreitzer E, Bourgeois B, Madl T. p53 Transactivation Domain Mediates Binding and Phase Separation with Poly-PR/GR. Int J Mol Sci 2021; 22:11431. [PMID: 34768862 PMCID: PMC8583712 DOI: 10.3390/ijms222111431] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/06/2021] [Accepted: 10/18/2021] [Indexed: 12/23/2022] Open
Abstract
The most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) is the presence of poly-PR/GR dipeptide repeats, which are encoded by the chromosome 9 open reading frame 72 (C9orf72) gene. Recently, it was shown that poly-PR/GR alters chromatin accessibility, which results in the stabilization and enhancement of transcriptional activity of the tumor suppressor p53 in several neurodegenerative disease models. A reduction in p53 protein levels protects against poly-PR and partially against poly-GR neurotoxicity in cells. Moreover, in model organisms, a reduction of p53 protein levels protects against neurotoxicity of poly-PR. Here, we aimed to study the detailed molecular mechanisms of how p53 contributes to poly-PR/GR-mediated neurodegeneration. Using a combination of biophysical techniques such as nuclear magnetic resonance (NMR) spectroscopy, fluorescence polarization, turbidity assays, and differential interference contrast (DIC) microscopy, we found that p53 physically interacts with poly-PR/GR and triggers liquid-liquid phase separation of p53. We identified the p53 transactivation domain 2 (TAD2) as the main binding site for PR25/GR25 and showed that binding of poly-PR/GR to p53 is mediated by a network of electrostatic and/or hydrophobic interactions. Our findings might help to understand the mechanistic role of p53 in poly-PR/GR-associated neurodegeneration.
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Affiliation(s)
- Sinem Usluer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (S.U.); (E.S.); (B.B.)
| | - Emil Spreitzer
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (S.U.); (E.S.); (B.B.)
| | - Benjamin Bourgeois
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (S.U.); (E.S.); (B.B.)
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Aging, Department of Molecular Biology and Biochemistry, Medical University of Graz, 8010 Graz, Austria; (S.U.); (E.S.); (B.B.)
- BioTechMed-Graz, 8010 Graz, Austria
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34
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Liguori F, Amadio S, Volonté C. Fly for ALS: Drosophila modeling on the route to amyotrophic lateral sclerosis modifiers. Cell Mol Life Sci 2021; 78:6143-6160. [PMID: 34322715 PMCID: PMC11072332 DOI: 10.1007/s00018-021-03905-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 12/11/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a rare, devastating disease, causing movement impairment, respiratory failure and ultimate death. A plethora of genetic, cellular and molecular mechanisms are involved in ALS signature, although the initiating causes and progressive pathological events are far from being understood. Drosophila research has produced seminal discoveries for more than a century and has been successfully used in the past 25 years to untangle the process of ALS pathogenesis, and recognize potential markers and novel strategies for therapeutic solutions. This review will provide an updated view of several ALS modifiers validated in C9ORF72, SOD1, FUS, TDP-43 and Ataxin-2 Drosophila models. We will discuss basic and preclinical findings, illustrating recent developments and novel breakthroughs, also depicting unsettled challenges and limitations in the Drosophila-ALS field. We intend to stimulate a renewed debate on Drosophila as a screening route to identify more successful disease modifiers and neuroprotective agents.
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Affiliation(s)
- Francesco Liguori
- Preclinical Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 65, 00143, Rome, Italy
| | - Susanna Amadio
- Preclinical Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 65, 00143, Rome, Italy
| | - Cinzia Volonté
- Preclinical Neuroscience, IRCCS Fondazione Santa Lucia, Via del Fosso di Fiorano 65, 00143, Rome, Italy.
- Institute for Systems Analysis and Computer Science "A. Ruberti", National Research Council (IASI-CNR), Via dei Taurini 19, 00185, Rome, Italy.
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35
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Zaepfel BL, Rothstein JD. RNA Is a Double-Edged Sword in ALS Pathogenesis. Front Cell Neurosci 2021; 15:708181. [PMID: 34349625 PMCID: PMC8326408 DOI: 10.3389/fncel.2021.708181] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/22/2021] [Indexed: 11/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurodegenerative disease that affects upper and lower motor neurons. Familial ALS accounts for a small subset of cases (<10-15%) and is caused by dominant mutations in one of more than 10 known genes. Multiple genes have been causally or pathologically linked to both ALS and frontotemporal dementia (FTD). Many of these genes encode RNA-binding proteins, so the role of dysregulated RNA metabolism in neurodegeneration is being actively investigated. In addition to defects in RNA metabolism, recent studies provide emerging evidence into how RNA itself can contribute to the degeneration of both motor and cortical neurons. In this review, we discuss the roles of altered RNA metabolism and RNA-mediated toxicity in the context of TARDBP, FUS, and C9ORF72 mutations. Specifically, we focus on recent studies that describe toxic RNA as the potential initiator of disease, disease-associated defects in specific RNA metabolism pathways, as well as how RNA-based approaches can be used as potential therapies. Altogether, we highlight the importance of RNA-based investigations into the molecular progression of ALS, as well as the need for RNA-dependent structural studies of disease-linked RNA-binding proteins to identify clear therapeutic targets.
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Affiliation(s)
- Benjamin L Zaepfel
- Biochemistry, Cellular and Molecular Biology Program, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Molecular Biology and Genetics Department, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States
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36
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Solomon DA, Smikle R, Reid MJ, Mizielinska S. Altered Phase Separation and Cellular Impact in C9orf72-Linked ALS/FTD. Front Cell Neurosci 2021; 15:664151. [PMID: 33967699 PMCID: PMC8096919 DOI: 10.3389/fncel.2021.664151] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 03/19/2021] [Indexed: 12/21/2022] Open
Abstract
Since the discovery of the C9orf72 repeat expansion mutation as causative for chromosome 9-linked amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) in 2011, a multitude of cellular pathways have been implicated. However, evidence has also been accumulating for a key mechanism of cellular compartmentalization—phase separation. Liquid-liquid phase separation (LLPS) is fundamental for the formation of membraneless organelles including stress granules, the nucleolus, Cajal bodies, nuclear speckles and the central channel of the nuclear pore. Evidence has now accumulated showing that the formation and function of these membraneless organelles is impaired by both the toxic arginine rich dipeptide repeat proteins (DPRs), translated from the C9orf72 repeat RNA transcript, and the repeat RNA itself. Both the arginine rich DPRs and repeat RNA themselves undergo phase separation and disrupt the physiological phase separation of proteins involved in the formation of these liquid-like organelles. Hence abnormal phase separation may explain a number of pathological cellular phenomena associated with C9orf72-ALS/FTD. In this review article, we will discuss the principles of phase separation, phase separation of the DPRs and repeat RNA themselves and how they perturb LLPS associated with membraneless organelles and the functional consequences of this. We will then discuss how phase separation may impact the major pathological feature of C9orf72-ALS/FTD, TDP-43 proteinopathy, and how LLPS may be targeted therapeutically in disease.
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Affiliation(s)
- Daniel A Solomon
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Rebekah Smikle
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Matthew J Reid
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
| | - Sarah Mizielinska
- UK Dementia Research Institute at King's College London, London, United Kingdom.,Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, United Kingdom
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37
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Lee PJ, Yang S, Sun Y, Guo JU. Regulation of nonsense-mediated mRNA decay in neural development and disease. J Mol Cell Biol 2021; 13:269-281. [PMID: 33783512 PMCID: PMC8339359 DOI: 10.1093/jmcb/mjab022] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 01/27/2021] [Accepted: 02/05/2021] [Indexed: 11/26/2022] Open
Abstract
Eukaryotes have evolved a variety of mRNA surveillance mechanisms to detect and degrade aberrant mRNAs with potential deleterious outcomes. Among them, nonsense-mediated mRNA decay (NMD) functions not only as a quality control mechanism targeting aberrant mRNAs containing a premature termination codon but also as a posttranscriptional gene regulation mechanism targeting numerous physiological mRNAs. Despite its well-characterized molecular basis, the regulatory scope and biological functions of NMD at an organismal level are incompletely understood. In humans, mutations in genes encoding core NMD factors cause specific developmental and neurological syndromes, suggesting a critical role of NMD in the central nervous system. Here, we review the accumulating biochemical and genetic evidence on the developmental regulation and physiological functions of NMD as well as an emerging role of NMD dysregulation in neurodegenerative diseases.
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Affiliation(s)
- Paul Jongseo Lee
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA.,Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Suzhou Yang
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA.,Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
| | - Yu Sun
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Junjie U Guo
- Department of Neuroscience, Yale University School of Medicine, New Haven, CT 06520, USA.,Interdepartmental Neuroscience Program, Yale University, New Haven, CT 06520, USA
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38
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Zaepfel BL, Zhang Z, Maulding K, Coyne AN, Cheng W, Hayes LR, Lloyd TE, Sun S, Rothstein JD. UPF1 reduces C9orf72 HRE-induced neurotoxicity in the absence of nonsense-mediated decay dysfunction. Cell Rep 2021; 34:108925. [PMID: 33789100 PMCID: PMC8063722 DOI: 10.1016/j.celrep.2021.108925] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2020] [Revised: 12/22/2020] [Accepted: 03/09/2021] [Indexed: 01/29/2023] Open
Abstract
Multiple cellular pathways have been suggested to be altered by the C9orf72 GGGGCC (G4C2) hexanucleotide repeat expansion (HRE), including aspects of RNA regulation such as nonsense-mediated decay (NMD). Here, we investigate the role that overexpression of UPF1, a protein involved in NMD, plays in mitigating neurotoxicity in multiple models of C9orf72 ALS/FTD. First, we show that NMD is not altered in our endogenous induced pluripotent stem cell (iPSC)-derived spinal neuron (iPSN) model of C9orf72 ALS (C9-ALS) or postmortem motor cortex tissue from C9-ALS patients. Unexpectedly, we find that UPF1 overexpression significantly reduces the severity of known neurodegenerative phenotypes without altering NMD function itself. UPF1 overexpression reduces poly(GP) abundance without altering the amount of repeat RNA, providing a potential mechanism by which UPF1 reduces dipeptide repeat (DPR) protein-mediated toxicity. Together, these findings indicate that UPF1 is neuroprotective in the context of C9-ALS, albeit independent of known UPF1-mediated NMD pathways.
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Affiliation(s)
- Benjamin L Zaepfel
- Biochemistry, Cellular and Molecular Biology Program, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Molecular Biology and Genetics Department, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhe Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Kirstin Maulding
- Brain Science Institute, 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
| | - Alyssa N Coyne
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Weiwei Cheng
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lindsey R Hayes
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Thomas E Lloyd
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Shuying Sun
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Jeffrey D Rothstein
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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39
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Gill AL, Premasiri AS, Vieira FG. Hypothesis and Theory: Roles of Arginine Methylation in C9orf72-Mediated ALS and FTD. Front Cell Neurosci 2021; 15:633668. [PMID: 33833668 PMCID: PMC8021787 DOI: 10.3389/fncel.2021.633668] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/09/2021] [Indexed: 12/11/2022] Open
Abstract
Hexanucleotide repeat expansion (G4C2n) mutations in the gene C9ORF72 account for approximately 30% of familial cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), as well as approximately 7% of sporadic cases of ALS. G4C2n mutations are known to result in the production of five species of dipeptide repeat proteins (DRPs) through non-canonical translation processes. Arginine-enriched dipeptide repeat proteins, glycine-arginine (polyGR), and proline-arginine (polyPR) have been demonstrated to be cytotoxic and deleterious in multiple experimental systems. Recently, we and others have implicated methylation of polyGR/polyPR arginine residues in disease processes related to G4C2n mutation-mediated neurodegeneration. We previously reported that inhibition of asymmetric dimethylation (ADMe) of arginine residues is protective in cell-based models of polyGR/polyPR cytotoxicity. These results are consistent with the idea that PRMT-mediated arginine methylation in the context of polyGR/polyPR exposure is harmful. However, it remains unclear why. Here we discuss the influence of arginine methylation on diverse cellular processes including liquid-liquid phase separation, chromatin remodeling, transcription, RNA processing, and RNA-binding protein localization, and we consider how methylation of polyGR/polyPR may disrupt processes essential for normal cellular function and survival.
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Affiliation(s)
- Anna L Gill
- ALS Therapy Development Institute, Cambridge, MA, United States
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40
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Tsai YL, Manley JL. Multiple ways to a dead end: diverse mechanisms by which ALS mutant genes induce cell death. Cell Cycle 2021; 20:631-646. [PMID: 33722167 DOI: 10.1080/15384101.2021.1886661] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a deadly neuromuscular disorder caused by progressive motor neuron loss in the brain and spinal cord. Over the past decades, a number of genetic mutations have been identified that cause or are associated with ALS disease progression. Numerous genes harbor ALS mutations, and they encode proteins displaying a wide range of physiological functions, with limited overlap. Despite the divergent functions, mutations in these genes typically trigger protein aggregation, which can confer gain- and/or loss-of-function to a number of essential cellular processes. Nuclear processes such as mRNA splicing and the response to DNA damage are significantly affected in ALS patients. Cytoplasmic organelles such as mitochondria are damaged by ALS mutant proteins. Processes that maintain cellular homeostasis such as autophagy, nonsense-mediated mRNA decay and nucleocytoplasmic transport, are also impaired by ALS mutations. Here, we review the multiple mechanisms by which mutations in major ALS-associated genes, such as TARDBP, C9ORF72 and FUS, lead to impairment of essential cellular processes.
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Affiliation(s)
- Yueh-Lin Tsai
- Department of Biological Sciences, Columbia University, New York, NY, United States
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, NY, United States
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41
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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: 33] [Impact Index Per Article: 8.3] [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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Loss of the fragile X syndrome protein FMRP results in misregulation of nonsense-mediated mRNA decay. Nat Cell Biol 2021; 23:40-48. [PMID: 33420492 PMCID: PMC8273690 DOI: 10.1038/s41556-020-00618-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/29/2020] [Indexed: 01/28/2023]
Abstract
Loss of the fragile X protein FMRP is a leading cause of intellectual disability and autism1,2, but the underlying mechanism remains poorly understood. We report that FMRP deficiency results in hyperactivated nonsense-mediated mRNA decay (NMD)3,4 in human SH-SY5Y neuroblastoma cells and fragile X syndrome (FXS) fibroblast-derived induced pluripotent stem cells (iPSCs). We examined the underlying mechanism and found that the key NMD factor UPF1 binds directly to FMRP, promoting FMRP binding to NMD targets. Our data indicate that FMRP acts as an NMD repressor. In the absence of FMRP, NMD targets are relieved from FMRP-mediated translational repression so that their half-lives are decreased and, for those NMD targets encoding NMD factors, increased translation produces abnormally high factor levels despite their hyperactivated NMD. Transcriptome-wide alterations caused by NMD hyperactivation have a role in the FXS phenotype. Consistent with this, small-molecule-mediated inhibition of hyperactivated NMD, which typifies iPSCs derived from patients with FXS, restores a number of neurodifferentiation markers, including those not deriving from NMD targets. Our mechanistic studies reveal that many molecular abnormalities in FMRP-deficient cells are attributable-either directly or indirectly-to misregulated NMD.
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Park JH, Chung CG, Seo J, Lee BH, Lee YS, Kweon JH, Lee SB. C9orf72-Associated Arginine-Rich Dipeptide Repeat Proteins Reduce the Number of Golgi Outposts and Dendritic Branches in Drosophila Neurons. Mol Cells 2020; 43:821-830. [PMID: 32975212 PMCID: PMC7528685 DOI: 10.14348/molcells.2020.0130] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 08/13/2020] [Accepted: 08/30/2020] [Indexed: 12/11/2022] Open
Abstract
Altered dendritic morphology is frequently observed in various neurological disorders including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), but the cellular and molecular basis underlying these pathogenic dendritic abnormalities remains largely unclear. In this study, we investigated dendritic morphological defects caused by dipeptide repeat protein (DPR) toxicity associated with G4C2 expansion mutation of C9orf72 (the leading genetic cause of ALS and FTD) in Drosophila neurons and characterized the underlying pathogenic mechanisms. Among the five DPRs produced by repeat-associated non-ATG translation of G4C2 repeats, we found that arginine-rich DPRs (PR and GR) led to the most significant reduction in dendritic branches and plasma membrane (PM) supply in Class IV dendritic arborization (C4 da) neurons. Furthermore, expression of PR and GR reduced the number of Golgi outposts (GOPs) in dendrites. In Drosophila brains, expression of PR, but not GR, led to a significant reduction in the mRNA level of CrebA, a transcription factor regulating the formation of GOPs. Overexpressing CrebA in PR-expressing C4 da neurons mitigated PM supply defects and restored the number of GOPs, but the number of dendritic branches remained unchanged, suggesting that other molecules besides CrebA may be involved in dendritic branching. Taken together, our results provide valuable insight into the understanding of dendritic pathology associated with C9-ALS/FTD.
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Affiliation(s)
- Jeong Hyang Park
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- These authors contributed equally to this work
| | - Chang Geon Chung
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- These authors contributed equally to this work
| | - Jinsoo Seo
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
| | - Byung-Hoon Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
| | - Young-Sam Lee
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Department of New Biology, DGIST, Daegu 42988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 2988, Korea
| | - Jung Hyun Kweon
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
| | - Sung Bae Lee
- Department of Brain & Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu 42988, Korea
- Protein Dynamics-Based Proteotoxicity Control Laboratory, Basic Research Lab, DGIST, Daegu 4988, Korea
- Well Aging Research Center, Division of Biotechnology, DGIST, Daegu 2988, Korea
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