1
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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: 10] [Impact Index Per Article: 3.3] [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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2
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Solomon DA, Mitchell JC, Salcher-Konrad MT, Vance CA, Mizielinska S. Review: Modelling the pathology and behaviour of frontotemporal dementia. Neuropathol Appl Neurobiol 2020; 45:58-80. [PMID: 30582188 DOI: 10.1111/nan.12536] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Accepted: 12/16/2018] [Indexed: 12/11/2022]
Abstract
Frontotemporal dementia (FTD) encompasses a collection of clinically and pathologically diverse neurological disorders. Clinical features of behavioural and language dysfunction are associated with neurodegeneration, predominantly of frontal and temporal cortices. Over the past decade, there have been significant advances in the understanding of the genetic aetiology and neuropathology of FTD which have led to the creation of various disease models to investigate the molecular pathways that contribute to disease pathogenesis. The generation of in vivo models of FTD involves either targeting genes with known disease-causative mutations such as GRN and C9orf72 or genes encoding proteins that form the inclusions that characterize the disease pathologically, such as TDP-43 and FUS. This review provides a comprehensive summary of the different in vivo model systems used to understand pathomechanisms in FTD, with a focus on disease models which reproduce aspects of the wide-ranging behavioural phenotypes seen in people with FTD. We discuss the emerging disease pathways that have emerged from these in vivo models and how this has shaped our understanding of disease mechanisms underpinning FTD. We also discuss the challenges of modelling the complex clinical symptoms shown by people with FTD, the confounding overlap with features of motor neuron disease, and the drive to make models more disease-relevant. In summary, in vivo models can replicate many pathological and behavioural aspects of clinical FTD, but robust and thorough investigations utilizing shared features and variability between disease models will improve the disease-relevance of findings and thus better inform therapeutic development.
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Affiliation(s)
- D A Solomon
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - J C Mitchell
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - M-T Salcher-Konrad
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - C A Vance
- Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
| | - S Mizielinska
- UK Dementia Research Institute, King's College London, London, Camberwell, UK.,Department of Basic & Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, Maurice Wohl Clinical Neuroscience Institute, London, Camberwell, UK
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3
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Williamson MG, Finelli MJ, Sleigh JN, Reddington A, Gordon D, Talbot K, Davies KE, Oliver PL. Neuronal over-expression of Oxr1 is protective against ALS-associated mutant TDP-43 mislocalisation in motor neurons and neuromuscular defects in vivo. Hum Mol Genet 2020; 28:3584-3599. [PMID: 31642482 PMCID: PMC6927465 DOI: 10.1093/hmg/ddz190] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 07/04/2019] [Accepted: 07/26/2019] [Indexed: 12/12/2022] Open
Abstract
A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and the related neurodegenerative disorder frontotemporal dementia, is the cellular mislocalization of transactive response DNA-binding protein 43 kDa (TDP-43). Additionally, multiple mutations in the TARDBP gene (encoding TDP-43) are associated with familial forms of ALS. While the exact role for TDP-43 in the onset and progression of ALS remains unclear, the identification of factors that can prevent aberrant TDP-43 localization and function could be clinically beneficial. Previously, we discovered that the oxidation resistance 1 (Oxr1) protein could alleviate cellular mislocalization phenotypes associated with TDP-43 mutations, and that over-expression of Oxr1 was able to delay neuromuscular abnormalities in the hSOD1G93A ALS mouse model. Here, to determine whether Oxr1 can protect against TDP-43-associated phenotypes in vitro and in vivo, we used the same genetic approach in a newly described transgenic mouse expressing the human TDP-43 locus harbouring an ALS disease mutation (TDP-43M337V). We show in primary motor neurons from TDP-43M337V mice that genetically-driven Oxr1 over-expression significantly alleviates cytoplasmic mislocalization of mutant TDP-43. We also further quantified newly-identified, late-onset neuromuscular phenotypes of this mutant line, and demonstrate that neuronal Oxr1 over-expression causes a significant reduction in muscle denervation and neuromuscular junction degeneration in homozygous mutants in parallel with improved motor function and a reduction in neuroinflammation. Together these data support the application of Oxr1 as a viable and safe modifier of TDP-43-associated ALS phenotypes.
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Affiliation(s)
- Matthew G Williamson
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Mattéa J Finelli
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - James N Sleigh
- Department of Neuromuscular Diseases, Institute of Neurology, University College London, London WC1N 3BG, UK.,UK Dementia Research Institute, University College London, London WC1E 6BT, UK
| | - Amy Reddington
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - David Gordon
- Nuffield Department of Clinical Neurosciences, University of Oxford, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Kevin Talbot
- Nuffield Department of Clinical Neurosciences, University of Oxford, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Kay E Davies
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK
| | - Peter L Oliver
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford OX1 3PT, UK.,MRC Harwell Institute, Harwell Campus, Didcot, Oxfordshire, OX11 0RD, UK
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4
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Huang SL, Wu LS, Lee M, Chang CW, Cheng WC, Fang YS, Chen YR, Cheng PL, Shen CKJ. A robust TDP-43 knock-in mouse model of ALS. Acta Neuropathol Commun 2020; 8:3. [PMID: 31964415 PMCID: PMC6975031 DOI: 10.1186/s40478-020-0881-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 12/10/2019] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal, adult-onset degenerative disorder of motor neurons. The diseased spinal cord motor neurons of more than 95% of amyotrophic lateral sclerosis (ALS) patients are characterized by the mis-metabolism of the RNA/DNA-binding protein TDP-43 (ALS-TDP), in particular, the presence of cytosolic aggregates of the protein. Most available mouse models for the basic or translational studies of ALS-TDP are based on transgenic overexpression of the TDP-43 protein. Here, we report the generation and characterization of mouse lines bearing homologous knock-in of fALS-associated mutation A315T and sALS-associated mutation N390D, respectively. Remarkably, the heterozygous TDP-43 (N390D/+) mice but not those heterozygous for the TDP-43 (A315T/+) mice develop a full spectrum of ALS-TDP-like pathologies at the molecular, cellular and behavioral levels. Comparative analysis of the mutant mice and spinal cord motor neurons (MN) derived from their embryonic stem (ES) cells demonstrates that different ALS-associated TDP-43 mutations possess critical ALS-causing capabilities and pathogenic pathways, likely modified by their genetic background and the environmental factors. Mechanistically, we identify aberrant RNA splicing of spinal cord Bcl-2 pre-mRNA and consequent increase of a negative regulator of autophagy, Bcl-2, which correlate with and are caused by a progressive increase of TDP-43, one of the early events associated with ALS-TDP pathogenesis, in the spinal cord of TDP-43 (N390D/+) mice and spinal cord MN derived from their ES cells. The TDP-43 (N390D/+) knock-in mice appear to be an ideal rodent model for basic as well as translational studies of ALS- TDP.
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5
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Kawakami I, Arai T, Hasegawa M. The basis of clinicopathological heterogeneity in TDP-43 proteinopathy. Acta Neuropathol 2019; 138:751-770. [PMID: 31555895 PMCID: PMC6800885 DOI: 10.1007/s00401-019-02077-x] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Revised: 08/27/2019] [Accepted: 09/13/2019] [Indexed: 12/15/2022]
Abstract
Transactive response DNA-binding protein 43 kDa (TDP-43) was identified as a major disease-associated component in the brain of patients with amyotrophic lateral sclerosis (ALS), as well as the largest subset of patients with frontotemporal lobar degeneration with ubiquitinated inclusions (FTLD-U), which characteristically exhibits cytoplasmic inclusions that are positive for ubiquitin but negative for tau and α-synuclein. TDP-43 pathology occurs in distinct brain regions, involves disparate brain networks, and features accumulation of misfolded proteins in various cell types and in different neuroanatomical regions. The clinical phenotypes of ALS and FTLD-TDP (FTLD with abnormal intracellular accumulations of TDP-43) correlate with characteristic distribution patterns of the underlying pathology across specific brain regions with disease progression. Recent studies support the idea that pathological protein spreads from neuron to neuron via axonal transport in a hierarchical manner. However, little is known to date about the basis of the selective cellular and regional vulnerability, although the information would have important implications for the development of targeted and personalized therapies. Here, we aim to summarize recent advances in the neuropathology, genetics and animal models of TDP-43 proteinopathy, and their relationship to clinical phenotypes for the underlying selective neuronal and regional susceptibilities. Finally, we attempt to integrate these findings into the emerging picture of TDP-43 proteinopathy, and to highlight key issues for future therapy and research.
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Affiliation(s)
- Ito Kawakami
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan
- Department of Neuropathology, Tokyo Metropolitan Geriatric Hospital and Institute, Tokyo, Japan
| | - Tetsuaki Arai
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
- Department of Psychiatry, Division of Clinical Medicine, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6, Kamikitazawa, Setagaya-ku, Tokyo, 156-8506, Japan.
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6
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Bolognesi B, Faure AJ, Seuma M, Schmiedel JM, Tartaglia GG, Lehner B. The mutational landscape of a prion-like domain. Nat Commun 2019; 10:4162. [PMID: 31519910 PMCID: PMC6744496 DOI: 10.1038/s41467-019-12101-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2019] [Accepted: 08/15/2019] [Indexed: 12/11/2022] Open
Abstract
Insoluble protein aggregates are the hallmarks of many neurodegenerative diseases. For example, aggregates of TDP-43 occur in nearly all cases of amyotrophic lateral sclerosis (ALS). However, whether aggregates cause cellular toxicity is still not clear, even in simpler cellular systems. We reasoned that deep mutagenesis might be a powerful approach to disentangle the relationship between aggregation and toxicity. We generated >50,000 mutations in the prion-like domain (PRD) of TDP-43 and quantified their toxicity in yeast cells. Surprisingly, mutations that increase hydrophobicity and aggregation strongly decrease toxicity. In contrast, toxic variants promote the formation of dynamic liquid-like condensates. Mutations have their strongest effects in a hotspot that genetic interactions reveal to be structured in vivo, illustrating how mutagenesis can probe the in vivo structures of unstructured proteins. Our results show that aggregation of TDP-43 is not harmful but protects cells, most likely by titrating the protein away from a toxic liquid-like phase. TDP43 aggregates are a hallmark of amyotrophic lateral sclerosis. By using deep mutagenesis to measure the toxicity of more than 50,000 mutations in the prion domain of TDP43, the authors conclude that mutations that increase toxicity promote formation of liquid-like condensates, while aggregation of TDP43 is protective for the cell.
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Affiliation(s)
- Benedetta Bolognesi
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain. .,Institute of Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain.
| | - Andre J Faure
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain
| | - Mireia Seuma
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain.,Institute of Bioengineering of Catalonia (IBEC), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Jörn M Schmiedel
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain
| | - Gian Gaetano Tartaglia
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, Spain.,Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Spain.,Department of Biology 'Charles Darwin', Sapienza University of Rome, P.le A. Moro 5, Rome, 00185, Italy
| | - Ben Lehner
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Doctor Aiguader 88, 08003, Barcelona, Spain. .,Universitat Pompeu Fabra (UPF), Barcelona, Spain. .,Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08010, Barcelona, Spain.
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7
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Berning BA, Walker AK. The Pathobiology of TDP-43 C-Terminal Fragments in ALS and FTLD. Front Neurosci 2019; 13:335. [PMID: 31031584 PMCID: PMC6470282 DOI: 10.3389/fnins.2019.00335] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/22/2019] [Indexed: 12/11/2022] Open
Abstract
During neurodegenerative disease, the multifunctional RNA-binding protein TDP-43 undergoes a vast array of post-translational modifications, including phosphorylation, acetylation, and cleavage. Many of these alterations may directly contribute to the pathogenesis of TDP-43 proteinopathies, which include most forms of amyotrophic lateral sclerosis (ALS) and approximately half of all frontotemporal dementia, pathologically identified as frontotemporal lobar degeneration (FTLD) with TDP-43 pathology. However, the relative contributions of the various TDP-43 post-translational modifications to disease remain unclear, and indeed some may be secondary epiphenomena rather than disease-causative. It is therefore critical to determine the involvement of each modification in disease processes to allow the design of targeted treatments. In particular, TDP-43 C-terminal fragments (CTFs) accumulate in the brains of people with ALS and FTLD and are therefore described as a neuropathological signature of these diseases. Remarkably, these TDP-43 CTFs are rarely observed in the spinal cord, even in ALS which involves dramatic degeneration of spinal motor neurons. Therefore, TDP-43 CTFs are not produced non-specifically in the course of all forms of TDP-43-related neurodegeneration, but rather variably arise due to additional factors influenced by regional heterogeneity in the central nervous system. In this review, we summarize how TDP-43 CTFs are generated and degraded by cells, and critique evidence from studies of TDP-43 CTF pathology in human disease tissues, as well as cell and animal models, to analyze the pathophysiological relevance of TDP-43 CTFs to ALS and FTLD. Numerous studies now indicate that, although TDP-43 CTFs are prevalent in ALS and FTLD brains, disease-related pathology is only variably reproduced in TDP-43 CTF cell culture models. Furthermore, TDP-43 CTF expression in both transgenic and viral-mediated in vivo models largely fails to induce motor or behavioral dysfunction reminiscent of human disease. We therefore conclude that although TDP-43 CTFs are a hallmark of TDP-43-related neurodegeneration in the brain, they are not a primary cause of ALS or FTLD.
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Affiliation(s)
- Britt A. Berning
- Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
| | - Adam K. Walker
- Neurodegeneration Pathobiology Laboratory, Queensland Brain Institute, University of Queensland, Brisbane, QLD, Australia
- Centre for Motor Neuron Disease Research, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Macquarie University, North Ryde, NSW, Australia
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8
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Miguel L, Avequin T, Pons M, Frebourg T, Campion D, Lecourtois M. FTLD/ALS-linked TDP-43 mutations do not alter TDP-43's ability to self-regulate its expression in Drosophila. Brain Res 2018; 1695:1-9. [PMID: 29778779 DOI: 10.1016/j.brainres.2018.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 05/16/2018] [Accepted: 05/17/2018] [Indexed: 10/16/2022]
Abstract
TDP-43 is a major disease-causing protein in amyotrophic lateral sclerosis (ALS) and Frontotemporal Lobar Degeneration (FTLD). Today, >50 missense mutations in the TARDBP/TDP-43 gene have been described in patients with FTLD/ALS. However, the functional consequences of FTLD/ALS-linked TDP-43 mutations are not fully elucidated. In the physiological state, TDP-43 expression is tightly regulated through an autoregulatory negative feedback loop. Maintaining normal TDP-43 protein levels is critical for proper physiological functions of the cells. In the present study, we investigated whether the FTLD/ALS-associated mutations could interfere with TDP-43 protein's capacity to modulate its own protein levels using Drosophila as an experimental model. Our data show that FTLD/ALS-associated mutant proteins regulate TDP-43 production with the same efficiency as the wild-type form of the protein. Thus, FTLD/ALS-linked TDP-43 mutations do not alter TDP-43's ability to self-regulate its expression and consequently of the homeostasis of TDP-43 protein levels.
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Affiliation(s)
- Laetitia Miguel
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Tracey Avequin
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Marine Pons
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France
| | - Thierry Frebourg
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France; Department of Genetics, Rouen University Hospital, 76301 Rouen, France
| | - Dominique Campion
- Normandie University, UNIROUEN, Inserm, U1245, IRIB, Rouen, France; Centre Hospitalier du Rouvray, Sotteville-Lès-Rouen, France
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9
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van Hummel A, Chan G, van der Hoven J, Morsch M, Ippati S, Suh L, Bi M, Asih PR, Lee WS, Butler TA, Przybyla M, Halliday GM, Piguet O, Kiernan MC, Chung RS, Ittner LM, Ke YD. Selective Spatiotemporal Vulnerability of Central Nervous System Neurons to Pathologic TAR DNA-Binding Protein 43 in Aged Transgenic Mice. THE AMERICAN JOURNAL OF PATHOLOGY 2018; 188:1447-1456. [DOI: 10.1016/j.ajpath.2018.03.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/19/2018] [Accepted: 03/08/2018] [Indexed: 12/14/2022]
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10
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Differential Neurotoxicity Related to Tetracycline Transactivator and TDP-43 Expression in Conditional TDP-43 Mouse Model of Frontotemporal Lobar Degeneration. J Neurosci 2018; 38:6045-6062. [PMID: 29807909 DOI: 10.1523/jneurosci.1836-17.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 04/23/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022] Open
Abstract
Frontotemporal lobar degeneration (FTLD) is among the most prevalent dementias of early-onset. Pathologically, FTLD presents with tauopathy or TAR DNA-binding protein 43 (TDP-43) proteinopathy. A biallelic mouse model of FTLD was produced on a mix FVB/129SVE background overexpressing wild-type human TDP-43 (hTDP-43) using tetracycline transactivator (tTA), a system widely used in mouse models of neurological disorders. tTA activates hTDP-43, which is placed downstream of the tetracycline response element. The original study on this transgenic mouse found hippocampal degeneration following hTDP-43 expression, but did not account for independent effects of tTA protein. Here, we initially analyzed the neurotoxic effects of tTA in postweaning age mice of either sex using immunostaining and area measurements of select brain regions. We observed tTA-dependent toxicity selectively in the hippocampus affecting the dentate gyrus significantly more than CA fields, whereas hTDP-43-dependent toxicity in bigenic mice occurred in most other cortical regions. Atrophy was associated with inflammation, activation of caspase-3, and loss of neurons. The atrophy associated with tTA expression was rescuable by the tetracycline analog, doxycycline, in the diet. MRI studies corroborated the patterns of atrophy. tTA-induced degeneration was strain-dependent and was rescued by moving the transgene onto a congenic C57BL/6 background. Despite significant hippocampal atrophy, behavioral tests in bigenic mice revealed no hippocampally mediated memory impairment. Significant atrophy in most cortical areas due solely to TDP-43 expression indicates that this mouse model remains useful for providing critical insight into co-occurrence of TDP-43 pathology, neurodegeneration, and behavioral deficits in FTLD.SIGNIFICANCE STATEMENT The tTA expression system has been widely used in mice to model neurological disorders. The technique allows investigators to reversibly turn on or off disease causing genes. Here, we report on a mouse model that overexpresses human TDP-43 using tTA and attempt to recapitulate features of TDP-43 pathology present in human FTLD. The tTA expression system is problematic, resulting in dramatic degeneration of the hippocampus. Thus, our study adds a note of caution for the use of the tTA system. However, because FTLD is primarily characterized by cortical degeneration and our mouse model shows significant atrophy in most cortical areas due to human TDP-43 overexpression, our animal model remains useful for providing critical insight on this human disease.
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11
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Fernandopulle MS, Prestil R, Grunseich C, Wang C, Gan L, Ward ME. Transcription Factor-Mediated Differentiation of Human iPSCs into Neurons. ACTA ACUST UNITED AC 2018; 79:e51. [PMID: 29924488 DOI: 10.1002/cpcb.51] [Citation(s) in RCA: 187] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Accurate modeling of human neuronal cell biology has been a long-standing challenge. However, methods to differentiate human induced pluripotent stem cells (iPSCs) to neurons have recently provided experimentally tractable cell models. Numerous methods that use small molecules to direct iPSCs into neuronal lineages have arisen in recent years. Unfortunately, these methods entail numerous challenges, including poor efficiency, variable cell type heterogeneity, and lengthy, expensive differentiation procedures. We recently developed a new method to generate stable transgenic lines of human iPSCs with doxycycline-inducible transcription factors at safe-harbor loci. Using a simple two-step protocol, these lines can be inducibly differentiated into either cortical (i3 Neurons) or lower motor neurons (i3 LMN) in a rapid, efficient, and scalable manner (Wang et al., 2017). In this manuscript, we describe a set of protocols to assist investigators in the culture and genetic engineering of iPSC lines to enable transcription factor-mediated differentiation of iPSCs into i3 Neurons or i3 LMNs, and we present neuronal culture conditions for various experimental applications. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Michael S Fernandopulle
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Ryan Prestil
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Christopher Grunseich
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
| | - Chao Wang
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California
| | - Li Gan
- Gladstone Institute of Neurological Disease, Gladstone Institutes, San Francisco, California
| | - Michael E Ward
- National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland
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12
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Gao J, Wang L, Huntley ML, Perry G, Wang X. Pathomechanisms of TDP-43 in neurodegeneration. J Neurochem 2018; 146:10.1111/jnc.14327. [PMID: 29486049 PMCID: PMC6110993 DOI: 10.1111/jnc.14327] [Citation(s) in RCA: 135] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/08/2018] [Accepted: 02/20/2018] [Indexed: 12/11/2022]
Abstract
Neurodegeneration, a term that refers to the progressive loss of structure and function of neurons, is a feature of many neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), frontotemporal lobar degeneration (FTLD), Alzheimer's disease (AD), Parkinson's disease (PD), and Huntington's disease (HD). There is no cure or treatment available that can prevent or reverse neurodegenerative conditions. The causes of neurodegeneration in these diseases remain largely unknown; yet, an extremely small proportion of these devastating diseases are associated with genetic mutations in proteins involved in a wide range of cellular pathways and processes. Over the past decade, it has become increasingly clear that the most notable neurodegenerative diseases, such as ALS, FTLD, and AD, share a common prominent pathological feature known as TAR DNA-binding protein 43 (TDP-43) proteinopathy, which is usually characterized by the presence of aberrant phosphorylation, ubiquitination, cleavage and/or nuclear depletion of TDP-43 in neurons and glial cells. The role of TDP-43 as a neurotoxicity trigger has been well documented in different in vitro and in vivo experimental models. As such, the investigation of TDP-43 pathomechanisms in various major neurodegenerative diseases is on the rise. Here, after a discussion of stages of TDP-43 proteinopathy during disease progression in various major neurodegenerative diseases, we review previous and most recent studies about the potential pathomechanisms with a particular emphasis on ALS, FTLD, and AD, and discuss the possibility of targeting TDP-43 as a common therapeutic approach to treat neurodegenerative diseases.
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Affiliation(s)
- Ju Gao
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Luwen Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Mikayla L. Huntley
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
| | - George Perry
- College of Sciences, University of Texas at San Antonio, San Antonio, Texas, USA
| | - Xinglong Wang
- Departments of Pathology, Case Western Reserve University, Cleveland, Ohio, USA
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Alzheimer’s Disease and Frontotemporal Lobar Degeneration: Mouse Models. NEURODEGENER DIS 2018. [DOI: 10.1007/978-3-319-72938-1_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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14
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Wobst HJ, Delsing L, Brandon NJ, Moss SJ. Truncation of the TAR DNA-binding protein 43 is not a prerequisite for cytoplasmic relocalization, and is suppressed by caspase inhibition and by introduction of the A90V sequence variant. PLoS One 2017; 12:e0177181. [PMID: 28510586 PMCID: PMC5433705 DOI: 10.1371/journal.pone.0177181] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 04/23/2017] [Indexed: 12/12/2022] Open
Abstract
The RNA-binding and -processing protein TAR DNA-binding protein 43 (TDP-43) is heavily linked to the underlying causes and pathology of neurodegenerative diseases such as amyotrophic lateral sclerosis and frontotemporal lobar degeneration. In these diseases, TDP-43 is mislocalized, hyperphosphorylated, ubiquitinated, aggregated and cleaved. The importance of TDP-43 cleavage in the disease pathogenesis is still poorly understood. Here we detail the use of D-sorbitol as an exogenous stressor that causes TDP-43 cleavage in HeLa cells, resulting in a 35 kDa truncated product that accumulates in the cytoplasm within one hour of treatment. We confirm that the formation of this 35 kDa cleavage product is mediated by the activation of caspases. Inhibition of caspases blocks the cleavage of TDP-43, but does not prevent the accumulation of full-length protein in the cytoplasm. Using D-sorbitol as a stressor and caspase activator, we also demonstrate that the A90V variant of TDP-43, which lies adjacent to the caspase cleavage site within the nuclear localization sequence of TDP-43, confers partial resistance against caspase-mediated generation of the 35 kDa cleavage product.
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Affiliation(s)
- Heike J. Wobst
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
| | - Louise Delsing
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Discovery Science, Innovative Medicines and Early Development Biotech Unit, Mölndal, Sweden
| | - Nicholas J. Brandon
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- AstraZeneca, Neuroscience, Innovative Medicines and Early Development, Waltham, MA, United States of America
| | - Stephen J. Moss
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Tufts University, Boston, MA, United States of America
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States of America
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15
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Wobst HJ, Wesolowski SS, Chadchankar J, Delsing L, Jacobsen S, Mukherjee J, Deeb TZ, Dunlop J, Brandon NJ, Moss SJ. Cytoplasmic Relocalization of TAR DNA-Binding Protein 43 Is Not Sufficient to Reproduce Cellular Pathologies Associated with ALS In vitro. Front Mol Neurosci 2017; 10:46. [PMID: 28286471 PMCID: PMC5323424 DOI: 10.3389/fnmol.2017.00046] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 02/10/2017] [Indexed: 12/12/2022] Open
Abstract
Mutations in the gene TARDBP, which encodes TAR DNA-binding protein 43 (TDP-43), are a rare cause of familial forms of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). While the majority of mutations are found in the C-terminal glycine-rich domain, an alanine to valine amino acid change at position 90 (A90V) in the bipartite nuclear localization signal (NLS) of TDP-43 has been described. This sequence variant has previously been shown to cause cytoplasmic mislocalization of TDP-43 and decrease protein solubility, leading to the formation of insoluble aggregates. Since the A90V mutation has been described both in patients as well as healthy controls, its pathogenic potential in ALS and FTD remains unclear. Here we compare properties of overexpressed A90V to the highly pathogenic M337V mutation. Though both mutations drive mislocalization of the protein to the cytoplasm to the same extent, M337V produces more significant damage in terms of protein solubility, levels of pathogenic phosphorylation, and formation of C-terminal truncated protein species. Furthermore, the M337V, but not the A90V mutant, leads to a downregulation of histone deacetylase 6 and Ras GTPase-activating protein-binding protein. We conclude that in the absence of another genetic or environmental ‘hit’ the A90V variant is not sufficient to cause the deleterious phenotypes associated with ALS and FTD, despite prominent cytoplasmic protein relocalization of TDP-43.
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Affiliation(s)
- Heike J Wobst
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, Boston MA, USA
| | - Steven S Wesolowski
- IMED Biotech Unit, AstraZeneca Neuroscience IMED, AstraZeneca, Cambridge MA, USA
| | - Jayashree Chadchankar
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, Boston MA, USA
| | - Louise Delsing
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, BostonMA, USA; IMED Biotech Unit, AstraZeneca Discovery ScienceMölndal, Sweden
| | - Steven Jacobsen
- IMED Biotech Unit, AstraZeneca Neuroscience IMED, AstraZeneca, Cambridge MA, USA
| | - Jayanta Mukherjee
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, Boston MA, USA
| | - Tarek Z Deeb
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, Boston MA, USA
| | - John Dunlop
- IMED Biotech Unit, AstraZeneca Neuroscience IMED, AstraZeneca, Cambridge MA, USA
| | - Nicholas J Brandon
- IMED Biotech Unit, AstraZeneca Neuroscience IMED, AstraZeneca, Cambridge MA, USA
| | - Stephen J Moss
- AstraZeneca-Tufts Laboratory for Basic and Translational Neuroscience, Department of Neuroscience, Tufts University School of Medicine, BostonMA, USA; Department of Neuroscience, Tufts University School of Medicine, BostonMA, USA
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16
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Conicella AE, Zerze GH, Mittal J, Fawzi NL. ALS Mutations Disrupt Phase Separation Mediated by α-Helical Structure in the TDP-43 Low-Complexity C-Terminal Domain. Structure 2016; 24:1537-49. [PMID: 27545621 DOI: 10.1016/j.str.2016.07.007] [Citation(s) in RCA: 546] [Impact Index Per Article: 68.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 06/20/2016] [Accepted: 07/10/2016] [Indexed: 12/14/2022]
Abstract
RNA-binding protein TDP-43 mediates essential RNA processing but forms cytoplasmic neuronal inclusions via its C-terminal domain (CTD) in amyotrophic lateral sclerosis (ALS). It remains unclear if aggregated TDP-43 is neurotoxic and if ∼50 ALS-associated missense mutations in TDP-43 CTD promote aggregation, or if loss of normal function plays a role in disease. Recent work points to the ability of related proteins to assemble into functional phase-separated ribonucleoprotein granules via their structurally disordered prion-like domains. Here, we provide atomic details on the structure and assembly of the low-complexity CTD of TDP-43 into liquid-liquid phase-separated in vitro granules and demonstrate that ALS-associated variants disrupt interactions within granules. Using nuclear magnetic resonance spectroscopy, simulation, and microscopy, we find that a subregion cooperatively but transiently folds into a helix that mediates TDP-43 phase separation. ALS-associated mutations disrupt phase separation by inhibiting interaction and helical stabilization. Therefore, ALS-associated mutations can disrupt TDP-43 interactions, affecting function beyond encouraging aggregation.
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Affiliation(s)
- Alexander E Conicella
- Graduate Program in Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Gül H Zerze
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Jeetain Mittal
- Department of Chemical and Biomolecular Engineering, Lehigh University, Bethlehem, PA 18015, USA
| | - Nicolas L Fawzi
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, RI 02912, USA.
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17
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Mass spectrometric analysis of accumulated TDP-43 in amyotrophic lateral sclerosis brains. Sci Rep 2016; 6:23281. [PMID: 26980269 PMCID: PMC4793195 DOI: 10.1038/srep23281] [Citation(s) in RCA: 109] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 03/03/2016] [Indexed: 12/12/2022] Open
Abstract
TDP-43 is the major disease-associated protein involved in the pathogenesis and progression of amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration with ubiquitin-positive inclusions linked to TDP-43 pathology (FTLD-TDP). Abnormal phosphorylation, truncation and cytoplasmic mis-localization are known to be the characteristics for the aggregated forms of TDP-43, and gain of toxic abnormal TDP-43 or loss of function of physiological TDP-43 have been suggested as the cause of neurodegeneration. However, most of the post-translational modifications or truncation sites in the abnormal TDP-43 in brains of patients remain to be identified by protein chemical analysis. In this study, we carried out a highly sensitive liquid chromatography-mass spectrometry analysis of Sarkosyl-insoluble pathological TDP-43 from brains of ALS patients and identified several novel phosphorylation sites, deamidation sites, and cleavage sites. Almost all modifications were localized in the Gly-rich C-terminal half. Most of the cleavage sites identified in this study are novel and are located in N-terminal half, suggesting that these sites may be more accessible to proteolytic enzymes. The data obtained in this study provide a foundation for the molecular mechanisms of TDP-43 aggregation and ALS pathogenesis.
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Ke YD, van Hummel A, Stevens CH, Gladbach A, Ippati S, Bi M, Lee WS, Krüger S, van der Hoven J, Volkerling A, Bongers A, Halliday G, Haass NK, Kiernan M, Delerue F, Ittner LM. Short-term suppression of A315T mutant human TDP-43 expression improves functional deficits in a novel inducible transgenic mouse model of FTLD-TDP and ALS. Acta Neuropathol 2015; 130:661-78. [PMID: 26437864 DOI: 10.1007/s00401-015-1486-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Revised: 09/26/2015] [Accepted: 09/27/2015] [Indexed: 12/28/2022]
Abstract
The nuclear transactive response DNA-binding protein 43 (TDP-43) undergoes relocalization to the cytoplasm with formation of cytoplasmic deposits in neurons in amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). Pathogenic mutations in the TDP-43-encoding TARDBP gene in familial ALS as well as non-mutant human TDP-43 have been utilized to model FTD/ALS in cell culture and animals, including mice. Here, we report novel A315T mutant TDP-43 transgenic mice, iTDP-43(A315T), with controlled neuronal over-expression. Constitutive expression of human TDP-43(A315T) resulted in pronounced early-onset and progressive neurodegeneration, which was associated with compromised motor performance, spatial memory and disinhibition. Muscle atrophy resulted in reduced grip strength. Cortical degeneration presented with pronounced astrocyte activation. Using differential protein extraction from iTDP-43(A315T) brains, we found cytoplasmic localization, fragmentation, phosphorylation and ubiquitination and insolubility of TDP-43. Surprisingly, suppression of human TDP-43(A315T) expression in mice with overt neurodegeneration for only 1 week was sufficient to significantly improve motor and behavioral deficits, and reduce astrogliosis. Our data suggest that functional deficits in iTDP-43(A315T) mice are at least in part a direct and transient effect of the presence of TDP-43(A315T). Furthermore, it illustrates the compensatory capacity of compromised neurons once transgenic TDP-43 is removed, with implications for future treatments.
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D'Alton S, Altshuler M, Lewis J. Studies of alternative isoforms provide insight into TDP-43 autoregulation and pathogenesis. RNA (NEW YORK, N.Y.) 2015; 21:1419-1432. [PMID: 26089325 PMCID: PMC4509932 DOI: 10.1261/rna.047647.114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 04/20/2015] [Indexed: 06/04/2023]
Abstract
TDP-43 is a soluble, nuclear protein that undergoes cytoplasmic redistribution and aggregation in the majority of cases of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 autoregulates the abundance of its own transcript TARDBP by binding to an intron in the 3' untranslated region, although the mechanisms underlying this activity have been debated. Herein, we provide the most extensive analysis of TARDBP transcript yet undertaken. We detail the existence of a plethora of complex splicing events and alternative poly(A) use and provide data that explain the discrepancies reported to date regarding the autoregulatory capacity of TDP-43. Additionally, although many splice isoforms emanating from the TARDBP locus contain the regulated intron in the 3' UTR, we find only evidence for autoregulation of the transcript encoding full-length TDP-43. Finally, we use a novel cytoplasmic isoform of TDP to induce disease-like loss of soluble, nuclear TDP-43, which results in aberrant splicing and up-regulation of endogenous TARDBP. These results reveal a previously underappreciated complexity to TDP-43 regulated splicing and suggest that loss of TDP-43 autoregulatory capacity may contribute to the pathogenesis of ALS.
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Affiliation(s)
- Simon D'Alton
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, Florida 32610, USA
| | - Marcelle Altshuler
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, Florida 32610, USA
| | - Jada Lewis
- Center for Translational Research in Neurodegenerative Disease, Department of Neuroscience, University of Florida, Gainesville, Florida 32610, USA
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21
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Abstract
Amyotrophic lateral sclerosis (ALS) is a devastating degenerative disease characterized by progressive loss of motor neurons in the motor cortex, brainstem, and spinal cord. Although defined as a motor disorder, ALS can arise concurrently with frontotemporal lobal dementia (FTLD). ALS begins focally but disseminates to cause paralysis and death. About 10% of ALS cases are caused by gene mutations, and more than 40 ALS-associated genes have been identified. While important questions about the biology of this disease remain unanswered, investigations of ALS genes have delineated pathogenic roles for (a) perturbations in protein stability and degradation, (b) altered homeostasis of critical RNA- and DNA-binding proteins, (c) impaired cytoskeleton function, and (d) non-neuronal cells as modifiers of the ALS phenotype. The rapidity of progress in ALS genetics and the subsequent acquisition of insights into the molecular biology of these genes provide grounds for optimism that meaningful therapies for ALS are attainable.
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22
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Buratti E. Functional Significance of TDP-43 Mutations in Disease. ADVANCES IN GENETICS 2015; 91:1-53. [DOI: 10.1016/bs.adgen.2015.07.001] [Citation(s) in RCA: 133] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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