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Santarelli S, Londero C, Soldano A, Candelaresi C, Todeschini L, Vernizzi L, Bellosta P. Drosophila melanogaster as a model to study autophagy in neurodegenerative diseases induced by proteinopathies. Front Neurosci 2023; 17:1082047. [PMID: 37274187 PMCID: PMC10232775 DOI: 10.3389/fnins.2023.1082047] [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: 10/27/2022] [Accepted: 04/14/2023] [Indexed: 06/06/2023] Open
Abstract
Proteinopathies are a large group of neurodegenerative diseases caused by both genetic and sporadic mutations in particular genes which can lead to alterations of the protein structure and to the formation of aggregates, especially toxic for neurons. Autophagy is a key mechanism for clearing those aggregates and its function has been strongly associated with the ubiquitin-proteasome system (UPS), hence mutations in both pathways have been associated with the onset of neurodegenerative diseases, particularly those induced by protein misfolding and accumulation of aggregates. Many crucial discoveries regarding the molecular and cellular events underlying the role of autophagy in these diseases have come from studies using Drosophila models. Indeed, despite the physiological and morphological differences between the fly and the human brain, most of the biochemical and molecular aspects regulating protein homeostasis, including autophagy, are conserved between the two species.In this review, we will provide an overview of the most common neurodegenerative proteinopathies, which include PolyQ diseases (Huntington's disease, Spinocerebellar ataxia 1, 2, and 3), Amyotrophic Lateral Sclerosis (C9orf72, SOD1, TDP-43, FUS), Alzheimer's disease (APP, Tau) Parkinson's disease (a-syn, parkin and PINK1, LRRK2) and prion diseases, highlighting the studies using Drosophila that have contributed to understanding the conserved mechanisms and elucidating the role of autophagy in these diseases.
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Affiliation(s)
- Stefania Santarelli
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
| | - Chiara Londero
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
| | - Alessia Soldano
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
- Department of Neuroscience, Scuola Internazionale Superiore di Studi Avanzati (SISSA), Trieste, Italy
| | - Carlotta Candelaresi
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
| | - Leonardo Todeschini
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
| | - Luisa Vernizzi
- Institute of Molecular Life Sciences, University of Zurich, Zürich, Switzerland
| | - Paola Bellosta
- Department of Cellular, Computational and Integrative Biology (CiBiO), University of Trento, Trento, Italy
- Department of Medicine, NYU Langone Medical Center, New York, NY, United States
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2
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Cendelin J, Cvetanovic M, Gandelman M, Hirai H, Orr HT, Pulst SM, Strupp M, Tichanek F, Tuma J, Manto M. Consensus Paper: Strengths and Weaknesses of Animal Models of Spinocerebellar Ataxias and Their Clinical Implications. THE CEREBELLUM 2021; 21:452-481. [PMID: 34378174 DOI: 10.1007/s12311-021-01311-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 01/02/2023]
Abstract
Spinocerebellar ataxias (SCAs) represent a large group of hereditary degenerative diseases of the nervous system, in particular the cerebellum, and other systems that manifest with a variety of progressive motor, cognitive, and behavioral deficits with the leading symptom of cerebellar ataxia. SCAs often lead to severe impairments of the patient's functioning, quality of life, and life expectancy. For SCAs, there are no proven effective pharmacotherapies that improve the symptoms or substantially delay disease progress, i.e., disease-modifying therapies. To study SCA pathogenesis and potential therapies, animal models have been widely used and are an essential part of pre-clinical research. They mainly include mice, but also other vertebrates and invertebrates. Each animal model has its strengths and weaknesses arising from model animal species, type of genetic manipulation, and similarity to human diseases. The types of murine and non-murine models of SCAs, their contribution to the investigation of SCA pathogenesis, pathological phenotype, and therapeutic approaches including their advantages and disadvantages are reviewed in this paper. There is a consensus among the panel of experts that (1) animal models represent valuable tools to improve our understanding of SCAs and discover and assess novel therapies for this group of neurological disorders characterized by diverse mechanisms and differential degenerative progressions, (2) thorough phenotypic assessment of individual animal models is required for studies addressing therapeutic approaches, (3) comparative studies are needed to bring pre-clinical research closer to clinical trials, and (4) mouse models complement cellular and invertebrate models which remain limited in terms of clinical translation for complex neurological disorders such as SCAs.
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Affiliation(s)
- Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic. .,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.
| | - Marija Cvetanovic
- Department of Neuroscience, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Mandi Gandelman
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Gunma, 371-8511, Japan.,Viral Vector Core, Gunma University Initiative for Advanced Research (GIAR), Gunma, 371-8511, Japan
| | - Harry T Orr
- Department of Laboratory Medicine and Pathology, Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, 175 North Medical Drive East, Salt Lake City, UT, 84132, USA
| | - Michael Strupp
- Department of Neurology and German Center for Vertigo and Balance Disorders, Hospital of the Ludwig-Maximilians University, Munich, Campus Grosshadern, Marchioninistr. 15, 81377, Munich, Germany
| | - Filip Tichanek
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic
| | - Jan Tuma
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 75, 323 00, Plzen, Czech Republic.,The Department of Cellular and Integrative Physiology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, MC 7843, San Antonio, TX, 78229, USA
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, CHU-Charleroi, Charleroi, Belgium.,Service des Neurosciences, Université de Mons, UMons, Mons, Belgium
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Russi M, Martin E, D'Autréaux B, Tixier L, Tricoire H, Monnier V. A Drosophila model of Friedreich ataxia with CRISPR/Cas9 insertion of GAA repeats in the frataxin gene reveals in vivo protection by N-acetyl cysteine. Hum Mol Genet 2020; 29:2831-2844. [PMID: 32744307 DOI: 10.1093/hmg/ddaa170] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/10/2020] [Accepted: 07/23/2020] [Indexed: 12/11/2022] Open
Abstract
Friedreich ataxia (FA) is caused by GAA repeat expansions in the first intron of FXN, the gene encoding frataxin, which results in decreased gene expression. Thanks to the high degree of frataxin conservation, the Drosophila melanogaster fruitfly appears as an adequate animal model to study this disease and to evaluate therapeutic interventions. Here, we generated a Drosophila model of FA with CRISPR/Cas9 insertion of approximately 200 GAA in the intron of the fly frataxin gene fh. These flies exhibit a developmental delay and lethality associated with decreased frataxin expression. We were able to bypass preadult lethality using genetic tools to overexpress frataxin only during the developmental period. These frataxin-deficient adults are short-lived and present strong locomotor defects. RNA-Seq analysis identified deregulation of genes involved in amino-acid metabolism and transcriptomic signatures of oxidative stress. In particular, we observed a progressive increase of Tspo expression, fully rescued by adult frataxin expression. Thus, Tspo expression constitutes a molecular marker of the disease progression in our fly model and might be of interest in other animal models or in patients. Finally, in a candidate drug screening, we observed that N-acetyl cysteine improved the survival, locomotor function, resistance to oxidative stress and aconitase activity of frataxin-deficient flies. Therefore, our model provides the opportunity to elucidate in vivo, the protective mechanisms of this molecule of therapeutic potential. This study also highlights the strength of the CRISPR/Cas9 technology to introduce human mutations in endogenous orthologous genes, leading to Drosophila models of human diseases with improved physiological relevance.
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Affiliation(s)
- Maria Russi
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Elodie Martin
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Benoit D'Autréaux
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université Paris-Saclay, Gif-sur-Yvette cedex 91198, France
| | - Laura Tixier
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Hervé Tricoire
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
| | - Véronique Monnier
- Université de Paris, BFA Unit of Functional and Adaptative Biology, UMR 8251, CNRS, Paris F-75013, France
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Koon AC, Chan HYE. Drosophila melanogaster As a Model Organism to Study RNA Toxicity of Repeat Expansion-Associated Neurodegenerative and Neuromuscular Diseases. Front Cell Neurosci 2017; 11:70. [PMID: 28377694 PMCID: PMC5359753 DOI: 10.3389/fncel.2017.00070] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/27/2017] [Indexed: 12/14/2022] Open
Abstract
For nearly a century, the fruit fly, Drosophila melanogaster, has proven to be a valuable tool in our understanding of fundamental biological processes, and has empowered our discoveries, particularly in the field of neuroscience. In recent years, Drosophila has emerged as a model organism for human neurodegenerative and neuromuscular disorders. In this review, we highlight a number of recent studies that utilized the Drosophila model to study repeat-expansion associated diseases (READs), such as polyglutamine diseases, fragile X-associated tremor/ataxia syndrome (FXTAS), myotonic dystrophy type 1 (DM1) and type 2 (DM2), and C9ORF72-associated amyotrophic lateral sclerosis/frontotemporal dementia (C9-ALS/FTD). Discoveries regarding the possible mechanisms of RNA toxicity will be focused here. These studies demonstrate Drosophila as an excellent in vivo model system that can reveal novel mechanistic insights into human disorders, providing the foundation for translational research and therapeutic development.
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Affiliation(s)
- Alex C Koon
- Laboratory of Drosophila ResearchHong Kong, Hong Kong; Biochemistry ProgramHong Kong, Hong Kong
| | - Ho Yin Edwin Chan
- Laboratory of Drosophila ResearchHong Kong, Hong Kong; Biochemistry ProgramHong Kong, Hong Kong; Cell and Molecular Biology ProgramHong Kong, Hong Kong; Molecular Biotechnology Program, Faculty of Science, School of Life SciencesHong Kong, Hong Kong; School of Life Sciences, Gerald Choa Neuroscience Centre, The Chinese University of Hong KongHong Kong, Hong Kong
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Absence of MutSβ leads to the formation of slipped-DNA for CTG/CAG contractions at primate replication forks. DNA Repair (Amst) 2016; 42:107-18. [PMID: 27155933 DOI: 10.1016/j.dnarep.2016.04.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 03/22/2016] [Accepted: 04/05/2016] [Indexed: 11/22/2022]
Abstract
Typically disease-causing CAG/CTG repeats expand, but rare affected families can display high levels of contraction of the expanded repeat amongst offspring. Understanding instability is important since arresting expansions or enhancing contractions could be clinically beneficial. The MutSβ mismatch repair complex is required for CAG/CTG expansions in mice and patients. Oddly, by unknown mechanisms MutSβ-deficient mice incur contractions instead of expansions. Replication using CTG or CAG as the lagging strand template is known to cause contractions or expansions respectively; however, the interplay between replication and repair leading to this instability remains unclear. Towards understanding how repeat contractions may arise, we performed in vitro SV40-mediated replication of repeat-containing plasmids in the presence or absence of mismatch repair. Specifically, we separated repair from replication: Replication mediated by MutSβ- and MutSα-deficient human cells or cell extracts produced slipped-DNA heteroduplexes in the contraction- but not expansion-biased replication direction. Replication in the presence of MutSβ disfavoured the retention of replication products harbouring slipped-DNA heteroduplexes. Post-replication repair of slipped-DNAs by MutSβ-proficient extracts eliminated slipped-DNAs. Thus, a MutSβ-deficiency likely enhances repeat contractions because MutSβ protects against contractions by repairing template strand slip-outs. Replication deficient in LigaseI or PCNA-interaction mutant LigaseI revealed slipped-DNA formation at lagging strands. Our results reveal that distinct mechanisms lead to expansions or contractions and support inhibition of MutSβ as a therapeutic strategy to enhance the contraction of expanded repeats.
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6
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Schmidt MHM, Pearson CE. Disease-associated repeat instability and mismatch repair. DNA Repair (Amst) 2015; 38:117-126. [PMID: 26774442 DOI: 10.1016/j.dnarep.2015.11.008] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 11/23/2015] [Accepted: 11/30/2015] [Indexed: 12/15/2022]
Abstract
Expanded tandem repeat sequences in DNA are associated with at least 40 human genetic neurological, neurodegenerative, and neuromuscular diseases. Repeat expansion can occur during parent-to-offspring transmission, and arise at variable rates in specific tissues throughout the life of an affected individual. Since the ongoing somatic repeat expansions can affect disease age-of-onset, severity, and progression, targeting somatic expansion holds potential as a therapeutic target. Thus, understanding the factors that regulate this mutation is crucial. DNA repair, in particular mismatch repair (MMR), is the major driving force of disease-associated repeat expansions. In contrast to its anti-mutagenic roles, mammalian MMR curiously drives the expansion mutations of disease-associated (CAG)·(CTG) repeats. Recent advances have broadened our knowledge of both the MMR proteins involved in disease repeat expansions, including: MSH2, MSH3, MSH6, MLH1, PMS2, and MLH3, as well as the types of repeats affected by MMR, now including: (CAG)·(CTG), (CGG)·(CCG), and (GAA)·(TTC) repeats. Mutagenic slipped-DNA structures have been detected in patient tissues, and the size of the slip-out and their junction conformation can determine the involvement of MMR. Furthermore, the formation of other unusual DNA and R-loop structures is proposed to play a key role in MMR-mediated instability. A complex correlation is emerging between tissues showing varying amounts of repeat instability and MMR expression levels. Notably, naturally occurring polymorphic variants of DNA repair genes can have dramatic effects upon the levels of repeat instability, which may explain the variation in disease age-of-onset, progression and severity. An increasing grasp of these factors holds prognostic and therapeutic potential.
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Affiliation(s)
- Monika H M Schmidt
- Genetics & Genome Biology, The Hospital for Sick Children, Peter Gilgan Centre for Research & Learning, 686 Bay St., Toronto, Ontario M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Bldg., 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Christopher E Pearson
- Genetics & Genome Biology, The Hospital for Sick Children, Peter Gilgan Centre for Research & Learning, 686 Bay St., Toronto, Ontario M5G 0A4, Canada; Department of Molecular Genetics, University of Toronto, Medical Sciences Bldg., 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
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7
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McGurk L, Berson A, Bonini NM. Drosophila as an In Vivo Model for Human Neurodegenerative Disease. Genetics 2015; 201:377-402. [PMID: 26447127 PMCID: PMC4596656 DOI: 10.1534/genetics.115.179457] [Citation(s) in RCA: 199] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Accepted: 08/19/2015] [Indexed: 12/13/2022] Open
Abstract
With the increase in the ageing population, neurodegenerative disease is devastating to families and poses a huge burden on society. The brain and spinal cord are extraordinarily complex: they consist of a highly organized network of neuronal and support cells that communicate in a highly specialized manner. One approach to tackling problems of such complexity is to address the scientific questions in simpler, yet analogous, systems. The fruit fly, Drosophila melanogaster, has been proven tremendously valuable as a model organism, enabling many major discoveries in neuroscientific disease research. The plethora of genetic tools available in Drosophila allows for exquisite targeted manipulation of the genome. Due to its relatively short lifespan, complex questions of brain function can be addressed more rapidly than in other model organisms, such as the mouse. Here we discuss features of the fly as a model for human neurodegenerative disease. There are many distinct fly models for a range of neurodegenerative diseases; we focus on select studies from models of polyglutamine disease and amyotrophic lateral sclerosis that illustrate the type and range of insights that can be gleaned. In discussion of these models, we underscore strengths of the fly in providing understanding into mechanisms and pathways, as a foundation for translational and therapeutic research.
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Affiliation(s)
- Leeanne McGurk
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Amit Berson
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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8
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Liu Y, Wilson SH. DNA base excision repair: a mechanism of trinucleotide repeat expansion. Trends Biochem Sci 2012; 37:162-72. [PMID: 22285516 DOI: 10.1016/j.tibs.2011.12.002] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Revised: 12/15/2011] [Accepted: 12/23/2011] [Indexed: 12/16/2022]
Abstract
The expansion of trinucleotide repeat (TNR) sequences in human DNA is considered to be a key factor in the pathogenesis of more than 40 neurodegenerative diseases. TNR expansion occurs during DNA replication and also, as suggested by recent studies, during the repair of DNA lesions produced by oxidative stress. In particular, the oxidized guanine base 8-oxoguanine within sequences containing CAG repeats may induce formation of pro-expansion intermediates through strand slippage during DNA base excision repair (BER). In this article, we describe how oxidized DNA lesions are repaired by BER and discuss the importance of the coordinated activities of the key repair enzymes, such as DNA polymerase β, flap endonuclease 1 (FEN1) and DNA ligase, in preventing strand slippage and TNR expansion.
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Affiliation(s)
- Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA.
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Abstract
Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder principally affecting the dopaminergic neurons of the substantia nigra. The pathogenic mechanisms are unknown and there are currently no cure or disease-modifying therapies. Recent genetic linkage studies have begun to identify single-gene mutations responsible for rare heritable forms of PD and define genetic risk factors contributing to disease prevalence in sporadic cases. These findings provide an opportunity to gain insight into the molecular mechanisms of this disorder through the creation and analysis of appropriate genetic models. One model system that has proven surprisingly tractable for these studies is the fruit fly, Drosophila melanogaster. Analysis of a number of Drosophila models of PD has revealed some profound and sometimes surprising insights into PD pathogenesis. Moreover, these models can be used to investigate potential therapeutic strategies that may be effective in vivo, and tests have highlighted the efficacy of a number of neuroprotective compounds. Here, I review the methodologies employed in developing the various Drosophila models, and the recent advances that these models in particular have contributed to our understanding of the mechanisms that underlie PD pathogenesis and possible treatment strategies.
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Affiliation(s)
- Alexander J Whitworth
- MRC Centre for Developmental and Biomedical Genetics, Department of Biomedical Sciences, University of Sheffield, Sheffield, UK
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10
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Liu G, Chen X, Bissler JJ, Sinden RR, Leffak M. Replication-dependent instability at (CTG) x (CAG) repeat hairpins in human cells. Nat Chem Biol 2010; 6:652-9. [PMID: 20676085 PMCID: PMC2924473 DOI: 10.1038/nchembio.416] [Citation(s) in RCA: 122] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Accepted: 06/30/2010] [Indexed: 12/03/2022]
Abstract
Instability of (CTG)•(CAG) microsatellite trinucleotide repeat (TNR) sequences is responsible for more than one dozen neurological or neuromuscular diseases. TNR instability during DNA synthesis is thought to involve slipped strand or hairpin structures in template or nascent DNA strands, although direct evidence for hairpin formation in human cells is lacking. We have used targeted recombination to create a series of isogenic HeLa cell lines in which (CTG)•(CAG) repeats are replicated from an ectopic copy of the c-myc replication origin. In this system the tendency of chromosomal (CTG)•(CAG) tracts to expand or contract was affected by origin location and the leading or lagging strand replication orientation of the repeats, and instability was enhanced by prolonged cell culture, increasing TNR length, and replication inhibition. Hairpin cleavage by synthetic zinc finger nucleases in these cells has provided the first direct evidence for the formation of hairpin structures during replication in vivo.
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Affiliation(s)
- Guoqi Liu
- Department of Biochemistry and Molecular Biology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
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11
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Gray M, Shirasaki DI, Cepeda C, André VM, Wilburn B, Lu XH, Tao J, Yamazaki I, Li SH, Sun YE, Li XJ, Levine MS, Yang XW. Full-length human mutant huntingtin with a stable polyglutamine repeat can elicit progressive and selective neuropathogenesis in BACHD mice. J Neurosci 2008; 28:6182-95. [PMID: 18550760 PMCID: PMC2630800 DOI: 10.1523/jneurosci.0857-08.2008] [Citation(s) in RCA: 480] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2008] [Revised: 05/02/2008] [Accepted: 05/04/2008] [Indexed: 11/21/2022] Open
Abstract
To elucidate the pathogenic mechanisms in Huntington's disease (HD) elicited by expression of full-length human mutant huntingtin (fl-mhtt), a bacterial artificial chromosome (BAC)-mediated transgenic mouse model (BACHD) was developed expressing fl-mhtt with 97 glutamine repeats under the control of endogenous htt regulatory machinery on the BAC. BACHD mice exhibit progressive motor deficits, neuronal synaptic dysfunction, and late-onset selective neuropathology, which includes significant cortical and striatal atrophy and striatal dark neuron degeneration. Power analyses reveal the robustness of the behavioral and neuropathological phenotypes, suggesting BACHD as a suitable fl-mhtt mouse model for preclinical studies. Additional analyses of BACHD mice provide novel insights into how mhtt may elicit neuropathogenesis. First, unlike previous fl-mhtt mouse models, BACHD mice reveal that the slowly progressive and selective pathogenic process in HD mouse brains can occur without early and diffuse nuclear accumulation of aggregated mhtt (i.e., as detected by immunostaining with the EM48 antibody). Instead, a relatively steady-state level of predominantly full-length mhtt and a small amount of mhtt N-terminal fragments are sufficient to elicit the disease process. Second, the polyglutamine repeat within fl-mhtt in BACHD mice is encoded by a mixed CAA-CAG repeat, which is stable in both the germline and somatic tissues including the cortex and striatum at the onset of neuropathology. Therefore, our results suggest that somatic repeat instability does not play a necessary role in selective neuropathogenesis in BACHD mice. In summary, the BACHD model constitutes a novel and robust in vivo paradigm for the investigation of HD pathogenesis and treatment.
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Affiliation(s)
- Michelle Gray
- Center for Neurobehavioral Genetics
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Dyna I. Shirasaki
- Center for Neurobehavioral Genetics
- Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095, and
| | - Carlos Cepeda
- Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Véronique M. André
- Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Brian Wilburn
- Center for Neurobehavioral Genetics
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Xiao-Hong Lu
- Center for Neurobehavioral Genetics
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Jifang Tao
- Departments of Molecular and Medical Pharmacology and
| | - Irene Yamazaki
- Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - Shi-Hua Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Yi E. Sun
- Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
- Departments of Molecular and Medical Pharmacology and
| | - Xiao-Jiang Li
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia 30322
| | - Michael S. Levine
- Mental Retardation Research Center, Semel Institute for Neuroscience and Human Behavior
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
| | - X. William Yang
- Center for Neurobehavioral Genetics
- Department of Psychiatry and Biobehavioral Sciences, Brain Research Institute
- David Geffen School of Medicine
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Moe SE, Sorbo JG, Holen T. Huntingtin triplet-repeat locus is stable under long-term Fen1 knockdown in human cells. J Neurosci Methods 2008; 171:233-8. [DOI: 10.1016/j.jneumeth.2008.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 03/16/2008] [Accepted: 03/20/2008] [Indexed: 11/29/2022]
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13
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Affiliation(s)
- Mark E Fortini
- Cancer and Developmental Biology Laboratory, National Cancer Institute, Frederick, MD 21702, USA.
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14
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Latouche M, Lasbleiz C, Martin E, Monnier V, Debeir T, Mouatt-Prigent A, Muriel MP, Morel L, Ruberg M, Brice A, Stevanin G, Tricoire H. A conditional pan-neuronal Drosophila model of spinocerebellar ataxia 7 with a reversible adult phenotype suitable for identifying modifier genes. J Neurosci 2007; 27:2483-92. [PMID: 17344386 PMCID: PMC6672519 DOI: 10.1523/jneurosci.5453-06.2007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Spinocerebellar ataxia 7 (SCA7) is a neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the ataxin 7 (ATXN7) protein, a member of a multiprotein complex involved in histone acetylation. We have created a conditional Drosophila model of SCA7 in which expression of truncated ATXN7 (ATXN7T) with a pathogenic polyQ expansion is induced in neurons in adult flies. In this model, mutant ATXN7T accumulated in neuronal intranuclear inclusions containing ubiquitin, the 19S proteasome subunit, and HSP70 (heat shock protein 70), as in patients. Aggregation was accompanied by a decrease in locomotion and lifespan but limited neuronal death. Disaggregation of the inclusions, when expression of expanded ATXN7T was stopped, correlated with improved locomotor function and increased lifespan, suggesting that the pathology may respond to treatment. Lifespan was then used as a quantitative marker in a candidate gene approach to validate the interest of the model and to identify generic modulators of polyQ toxicity and specific modifiers of SCA7. Several molecular pathways identified in this focused screen (proteasome function, unfolded protein stress, caspase-dependent apoptosis, and histone acetylation) were further studied in primary neuronal cultures. Sodium butyrate, a histone deacetylase inhibitor, improved the survival time of the neurons. This model is therefore a powerful tool for studying SCA7 and for the development of potential therapies for polyQ diseases.
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Affiliation(s)
- Morwena Latouche
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Christelle Lasbleiz
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Elodie Martin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Véronique Monnier
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Thomas Debeir
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Annick Mouatt-Prigent
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Marie-Paule Muriel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Lydie Morel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
| | - Merle Ruberg
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Alexis Brice
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Giovanni Stevanin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Hérvé Tricoire
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
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15
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Jung J, Bonini N. CREB-binding protein modulates repeat instability in a Drosophila model for polyQ disease. Science 2007; 315:1857-9. [PMID: 17332375 DOI: 10.1126/science.1139517] [Citation(s) in RCA: 113] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Although expansion of trinucleotide repeats accounts for over 30 human diseases, mechanisms of repeat instability remain poorly understood. We show that a Drosophila model for the CAG/polyglutamine (polyQ) disease spinocerebellar ataxia type 3 recapitulates key features of human CAG-repeat instability, including large repeat changes and strong expansion bias. Instability is dramatically enhanced by transcription and modulated by nuclear excision repair and a regulator of DNA repair adenosine 3',5'-monophosphate (cAMP) response element-binding protein (CREB)-binding protein-a histone acetyltransferase (HAT) whose decreased activity contributes to polyQ disease. Pharmacological treatment to normalize acetylation suppressed instability. Thus, toxic consequences of pathogenic polyQ protein may include enhancing repeat instability.
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Affiliation(s)
- Joonil Jung
- Department of Biology, University of Pennsylvania, Philadelphila, PA 19104, USA
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16
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van den Broek WJAA, Nelen MR, van der Heijden GW, Wansink DG, Wieringa B. Fen1does not control somatic hypermutability of the (CTG)n· (CAG)nrepeat in a knock-in mouse model for DM1. FEBS Lett 2006; 580:5208-14. [PMID: 16978612 DOI: 10.1016/j.febslet.2006.08.059] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Revised: 08/15/2006] [Accepted: 08/20/2006] [Indexed: 11/16/2022]
Abstract
The mechanism of trinucleotide repeat expansion, an important cause of neuromuscular and neurodegenerative diseases, is poorly understood. We report here on the study of the role of flap endonuclease 1 (Fen1), a structure-specific nuclease with both 5' flap endonuclease and 5'-3' exonuclease activity, in the somatic hypermutability of the (CTG)(n)*(CAG)(n) repeat of the DMPK gene in a mouse model for myotonic dystrophy type 1 (DM1). By intercrossing mice with Fen1 deficiency with transgenics with a DM1 (CTG)(n)*(CAG)(n) repeat (where 104n110), we demonstrate that Fen1 is not essential for faithful maintenance of this repeat in early embryonic cleavage divisions until the blastocyst stage. Additionally, we found that the frequency of somatic DM1 (CTG)(n)*(CAG)(n) repeat instability was essentially unaltered in mice with Fen1 haploinsufficiency up to 1.5 years of age. Based on these findings, we propose that Fen1, despite its role in DNA repair and replication, is not primarily involved in maintaining stability at the DM1 locus.
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Affiliation(s)
- Walther J A A van den Broek
- Department of Cell Biology, Radboud University Nijmegen Medical Centre, Nijmegen Centre for Molecular Life Sciences, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
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17
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Pearson CE, Nichol Edamura K, Cleary JD. Repeat instability: mechanisms of dynamic mutations. Nat Rev Genet 2005; 6:729-42. [PMID: 16205713 DOI: 10.1038/nrg1689] [Citation(s) in RCA: 645] [Impact Index Per Article: 33.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Disease-causing repeat instability is an important and unique form of mutation that is linked to more than 40 neurological, neurodegenerative and neuromuscular disorders. DNA repeat expansion mutations are dynamic and ongoing within tissues and across generations. The patterns of inherited and tissue-specific instability are determined by both gene-specific cis-elements and trans-acting DNA metabolic proteins. Repeat instability probably involves the formation of unusual DNA structures during DNA replication, repair and recombination. Experimental advances towards explaining the mechanisms of repeat instability have broadened our understanding of this mutational process. They have revealed surprising ways in which metabolic pathways can drive or protect from repeat instability.
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Affiliation(s)
- Christopher E Pearson
- Program of Genetics and Genomic Biology, The Hospital for Sick Children, 15-312, TMDT, 101 College Street, East Tower, Toronto, Ontario M5G 1L7, Canada.
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18
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Panigrahi GB, Lau R, Montgomery SE, Leonard MR, Pearson CE. Slipped (CTG)*(CAG) repeats can be correctly repaired, escape repair or undergo error-prone repair. Nat Struct Mol Biol 2005; 12:654-62. [PMID: 16025129 DOI: 10.1038/nsmb959] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2005] [Accepted: 06/06/2005] [Indexed: 01/23/2023]
Abstract
Expansion of (CTG)*(CAG) repeats, the cause of 14 or more diseases, is presumed to arise through escaped repair of slipped DNAs. We report the fidelity of slipped-DNA repair using human cell extracts and DNAs with slip-outs of (CAG)(20) or (CTG)(20). Three outcomes occurred: correct repair, escaped repair and error-prone repair. The choice of repair path depended on nick location and slip-out composition (CAG or CTG). A new form of error-prone repair was detected whereby excess repeats were incompletely excised, constituting a previously unknown path to generate expansions but not deletions. Neuron-like cell extracts yielded each of the three repair outcomes, supporting a role for these processes in (CTG)*(CAG) instability in patient post-mitotic brain cells. Mismatch repair (MMR) and nucleotide excision repair (NER) proteins hMSH2, hMSH3, hMLH1, XPF, XPG or polymerase beta were not required-indicating that their role in instability may precede that of slip-out processing. Differential processing of slipped repeats may explain the differences in mutation patterns between various disease loci or tissues.
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Affiliation(s)
- Gagan B Panigrahi
- Program of Genetics & Genomic Biology, The Hospital for Sick Children, 555 University Avenue, Elm Wing 11-135, Toronto, Ontario M5G 1X8, Canada
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