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Ruiz de Sabando A, Ciosi M, Galbete A, Cumming SA, Monckton DG, Ramos-Arroyo MA. Somatic CAG repeat instability in intermediate alleles of the HTT gene and its potential association with a clinical phenotype. Eur J Hum Genet 2024:10.1038/s41431-024-01546-6. [PMID: 38433266 DOI: 10.1038/s41431-024-01546-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 01/08/2024] [Accepted: 01/17/2024] [Indexed: 03/05/2024] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder caused by ≥36 CAGs in the HTT gene. Intermediate alleles (IAs) (27-35 CAGs) are not considered HD-causing, but their potential association with neurocognitive symptoms remains controversial. As HTT somatic CAG expansion influences HD onset, we hypothesised that IAs are somatically unstable, and that somatic CAG expansion may drive phenotypic presentation in some IA carriers. We quantified HTT somatic CAG expansions by MiSeq sequencing in the blood DNA of 164 HD subjects and 191 IA (symptomatic and control) carriers, and in the brain DNA of a symptomatic 33 CAG carrier. We also performed genotype-phenotype analysis. The phenotype of symptomatic IA carriers was characterised by motor (85%), cognitive (27%) and/or behavioural (29%) signs, with a late (58.7 ± 18.6 years), but not CAG-dependent, age at onset. IAs displayed somatic expansion that were CAG and age-dependent in blood DNA, with 0.4% and 0.01% of DNA molecules expanding by CAG and year, respectively. Somatic expansions of +1 and +2 CAGs were detected in the brain of the individual with 33 CAGs, with the highest expansion frequency in the putamen (10.3%) and the lowest in the cerebellum (4.8%). Somatic expansion in blood DNA was not different in symptomatic vs. control IA carriers. In conclusion, we show that HTT IAs are somatically unstable, but we found no association with HD-like phenotypes. It is plausible, however, that some IAs, close to the HD pathological threshold and with a predisposing genetic background, could manifest with neurocognitive symptoms.
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Affiliation(s)
- Ainara Ruiz de Sabando
- Department of Medical Genetics, Hospital Universitario de Navarra, IdiSNA, 31008, Pamplona, Spain
- Department of Health Sciences, Universidad Pública de Navarra, IdiSNA, 31008, Pamplona, Spain
- Fundación Miguel Servet-Navarrabiomed, IdiSNA, 31008, Pamplona, Spain
| | - Marc Ciosi
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Arkaitz Galbete
- Department of Statistics, Informatics and Mathematics, Universidad Pública de Navarra, IdiSNA, 31006, Pamplona, Spain
| | - Sarah A Cumming
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Darren G Monckton
- School of Molecular Biosciences, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Maria A Ramos-Arroyo
- Department of Medical Genetics, Hospital Universitario de Navarra, IdiSNA, 31008, Pamplona, Spain.
- Fundación Miguel Servet-Navarrabiomed, IdiSNA, 31008, Pamplona, Spain.
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Kim H, Gomez-Pastor R. HSF1 and Its Role in Huntington's Disease Pathology. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1410:35-95. [PMID: 36396925 DOI: 10.1007/5584_2022_742] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE OF REVIEW Heat shock factor 1 (HSF1) is the master transcriptional regulator of the heat shock response (HSR) in mammalian cells and is a critical element in maintaining protein homeostasis. HSF1 functions at the center of many physiological processes like embryogenesis, metabolism, immune response, aging, cancer, and neurodegeneration. However, the mechanisms that allow HSF1 to control these different biological and pathophysiological processes are not fully understood. This review focuses on Huntington's disease (HD), a neurodegenerative disease characterized by severe protein aggregation of the huntingtin (HTT) protein. The aggregation of HTT, in turn, leads to a halt in the function of HSF1. Understanding the pathways that regulate HSF1 in different contexts like HD may hold the key to understanding the pathomechanisms underlying other proteinopathies. We provide the most current information on HSF1 structure, function, and regulation, emphasizing HD, and discussing its potential as a biological target for therapy. DATA SOURCES We performed PubMed search to find established and recent reports in HSF1, heat shock proteins (Hsp), HD, Hsp inhibitors, HSF1 activators, and HSF1 in aging, inflammation, cancer, brain development, mitochondria, synaptic plasticity, polyglutamine (polyQ) diseases, and HD. STUDY SELECTIONS Research and review articles that described the mechanisms of action of HSF1 were selected based on terms used in PubMed search. RESULTS HSF1 plays a crucial role in the progression of HD and other protein-misfolding related neurodegenerative diseases. Different animal models of HD, as well as postmortem brains of patients with HD, reveal a connection between the levels of HSF1 and HSF1 dysfunction to mutant HTT (mHTT)-induced toxicity and protein aggregation, dysregulation of the ubiquitin-proteasome system (UPS), oxidative stress, mitochondrial dysfunction, and disruption of the structural and functional integrity of synaptic connections, which eventually leads to neuronal loss. These features are shared with other neurodegenerative diseases (NDs). Currently, several inhibitors against negative regulators of HSF1, as well as HSF1 activators, are developed and hold promise to prevent neurodegeneration in HD and other NDs. CONCLUSION Understanding the role of HSF1 during protein aggregation and neurodegeneration in HD may help to develop therapeutic strategies that could be effective across different NDs.
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Affiliation(s)
- Hyuck Kim
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Rocio Gomez-Pastor
- Department of Neuroscience, School of Medicine, University of Minnesota, Minneapolis, MN, USA.
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Iannucci J, Nizamutdinov D, Shapiro LA. Neurogenesis and chronic neurobehavioral outcomes are partially improved by vagus nerve stimulation in a mouse model of Gulf War Illness. Neurotoxicology 2022; 90:205-215. [DOI: 10.1016/j.neuro.2022.04.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/05/2022] [Accepted: 04/07/2022] [Indexed: 12/22/2022]
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Wipf P, Polyzos AA, McMurray CT. A Double-Pronged Sword: XJB-5-131 Is a Suppressor of Somatic Instability and Toxicity in Huntington's Disease. J Huntingtons Dis 2022; 11:3-15. [PMID: 34924397 PMCID: PMC9028625 DOI: 10.3233/jhd-210510] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Due to large increases in the elderly populations across the world, age-related diseases are expected to expand dramatically in the coming years. Among these, neurodegenerative diseases will be among the most devastating in terms of their emotional and economic impact on patients, their families, and associated subsidized health costs. There is no currently available cure or rescue for dying brain cells. Viable therapeutics for any of these disorders would be a breakthrough and provide relief for the large number of affected patients and their families. Neurodegeneration is accompanied by elevated oxidative damage and inflammation. While natural antioxidants have largely failed in clinical trials, preclinical phenotyping of the unnatural, mitochondrial targeted nitroxide, XJB-5-131, bodes well for further translational development in advanced animal models or in humans. Here we consider the usefulness of synthetic antioxidants for the treatment of Huntington's disease. The mitochondrial targeting properties of XJB-5-131 have great promise. It is both an electron scavenger and an antioxidant, reducing both somatic expansion and toxicity simultaneously through the same redox mechanism. By quenching reactive oxygen species, XJB-5-131 breaks the cycle between the rise in oxidative damage during disease progression and the somatic growth of the CAG repeat which depends on oxidation.
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Affiliation(s)
- Pater Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, USA
| | - Aris A. Polyzos
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Cynthia T. McMurray
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
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5
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CAG repeat-binding small molecule improves motor coordination impairment in a mouse model of Dentatorubral-pallidoluysian atrophy. Neurobiol Dis 2021; 163:105604. [PMID: 34968706 DOI: 10.1016/j.nbd.2021.105604] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/06/2021] [Accepted: 12/26/2021] [Indexed: 11/22/2022] Open
Abstract
Dentatorubral-pallidoluysian atrophy (DRPLA) is a devastating genetic disease presenting myoclonus, epilepsy, ataxia, and dementia. DRPLA is caused by the expansion of a CAG repeat in the ATN1 gene. Aggregation of the polyglutamine-expanded ATN1 protein causes neuro-degeneration of the dentatorubral and pallidoluysian systems. The expanded CAG repeats are unstable, and ongoing repeat expansions contribute to disease onset, progression, and severity. Inducing contractions of expanded repeats can be a means to treat DRPLA, for which no disease-modifying or curative therapies exist at present. Previously, we characterized a small molecule, naphthyridine-azaquinolone (NA), which binds to CAG slip-out structures and induces repeat contraction in Huntington's disease mice. Here, we demonstrate that long-term intracerebroventricular infusion of NA leads to repeat contraction, reductions in mutant ATN1 aggregation, and improved motor phenotype in a murine model of DRPLA. Furthermore, NA-induced contraction resulted in the modification of repeat-length-dependent dysregulation of gene expression profiles in DRPLA mice. Our study reveals the therapeutic potential of repeat contracting small molecules for repeat expansion disorders, such as DRPLA.
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de Sousa MML, Ye J, Luna L, Hildrestrand G, Bjørås K, Scheffler K, Bjørås M. Impact of Oxidative DNA Damage and the Role of DNA Glycosylases in Neurological Dysfunction. Int J Mol Sci 2021; 22:12924. [PMID: 34884729 PMCID: PMC8657561 DOI: 10.3390/ijms222312924] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Revised: 11/25/2021] [Accepted: 11/27/2021] [Indexed: 11/16/2022] Open
Abstract
The human brain requires a high rate of oxygen consumption to perform intense metabolic activities, accounting for 20% of total body oxygen consumption. This high oxygen uptake results in the generation of free radicals, including reactive oxygen species (ROS), which, at physiological levels, are beneficial to the proper functioning of fundamental cellular processes. At supraphysiological levels, however, ROS and associated lesions cause detrimental effects in brain cells, commonly observed in several neurodegenerative disorders. In this review, we focus on the impact of oxidative DNA base lesions and the role of DNA glycosylase enzymes repairing these lesions on brain function and disease. Furthermore, we discuss the role of DNA base oxidation as an epigenetic mechanism involved in brain diseases, as well as potential roles of DNA glycosylases in different epigenetic contexts. We provide a detailed overview of the impact of DNA glycosylases on brain metabolism, cognition, inflammation, tissue loss and regeneration, and age-related neurodegenerative diseases based on evidence collected from animal and human models lacking these enzymes, as well as post-mortem studies on patients with neurological disorders.
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Affiliation(s)
- Mirta Mittelstedt Leal de Sousa
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Jing Ye
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Luisa Luna
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
| | - Gunn Hildrestrand
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
| | - Karine Bjørås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
| | - Katja Scheffler
- Department of Neurology, St. Olavs Hospital, 7006 Trondheim, Norway;
- Department of Laboratory Medicine, St. Olavs Hospital, 7006 Trondheim, Norway
- Department of Neuromedicine and Movement Science, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Magnar Bjørås
- Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7028 Trondheim, Norway; (J.Y.); (K.B.)
- Department of Microbiology, Oslo University Hospital, University of Oslo, Rikshospitalet, 0424 Oslo, Norway; (L.L.); (G.H.)
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Islam J, So KH, Kc E, Moon HC, Kim A, Hyun SH, Kim S, Park YS. Transplantation of human embryonic stem cells alleviates motor dysfunction in AAV2-Htt171-82Q transfected rat model of Huntington's disease. Stem Cell Res Ther 2021; 12:585. [PMID: 34809707 PMCID: PMC8607638 DOI: 10.1186/s13287-021-02653-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Accepted: 11/01/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Human embryonic stem cells (hESCs) transplantation had shown to provide a potential source of cells in neurodegenerative disease studies and lead to behavioral recovery in lentivirus transfected or, toxin-induced Huntington's disease (HD) rodent model. Here, we aimed to observe if transplantation of superparamagnetic iron oxide nanoparticle (SPION)-labeled hESCs could migrate in the neural degenerated area and improve motor dysfunction in an AAV2-Htt171-82Q transfected Huntington rat model. METHODS All animals were randomly allocated into three groups at first: HD group, sham group, and control group. After six weeks, the animals of the HD group and sham group were again divided into two subgroups depending on animals receiving either ipsilateral or contralateral hESCs transplantation. We performed cylinder test and stepping test every two weeks after AAV2-Htt171-82Q injection and hESCs transplantation. Stem cell tracking was performed once per two weeks using T2 and T2*-weighted images at 4.7 Tesla MRI. We also performed immunohistochemistry and immunofluorescence staining to detect the presence of hESCs markers, huntingtin protein aggregations, and iron in the striatum. RESULTS After hESCs transplantation, the Htt virus-injected rats exhibited significant behavioral improvement in behavioral tests. SPION labeled hESCs showed migration with hypointense signal in MRI. The cells were positive with βIII-tubulin, GABA, and DARPP32. CONCLUSION Collectively, our results suggested that hESCs transplantation can be a potential treatment for motor dysfunction of Huntington's disease.
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Affiliation(s)
- Jaisan Islam
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Kyoung Ha So
- Institute for Stem Cell & Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Elina Kc
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Hyeong Cheol Moon
- Department of Neurosurgery, Gammaknife Icon Center, Chungbuk National University Hospital, Cheongju, Republic of Korea
| | - Aryun Kim
- Department of Neurology, Chungbuk National University Hospital, Cheongju, Republic of Korea
| | - Sang Hwan Hyun
- Institute for Stem Cell & Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
- Laboratory of Veterinary Embryology and Biotechnology (VETEMBIO), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Soochong Kim
- Institute for Stem Cell & Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
| | - Young Seok Park
- Department of Neuroscience, College of Medicine, Chungbuk National University, Cheongju, Republic of Korea.
- Institute for Stem Cell & Regenerative Medicine (ISCRM), College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea.
- Department of Neurosurgery, Gammaknife Icon Center, Chungbuk National University Hospital, Cheongju, Republic of Korea.
- Department of Neurosurgery, Chungbuk National University Hospital, College of Medicine, Chungbuk National University, 776, 1 Sunhwanro, Seowon-gu, Cheongju-si, Chungbuk, 28644, Republic of Korea.
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Abstract
At fifteen different genomic locations, the expansion of a CAG/CTG repeat causes a neurodegenerative or neuromuscular disease, the most common being Huntington's disease and myotonic dystrophy type 1. These disorders are characterized by germline and somatic instability of the causative CAG/CTG repeat mutations. Repeat lengthening, or expansion, in the germline leads to an earlier age of onset or more severe symptoms in the next generation. In somatic cells, repeat expansion is thought to precipitate the rate of disease. The mechanisms underlying repeat instability are not well understood. Here we review the mammalian model systems that have been used to study CAG/CTG repeat instability, and the modifiers identified in these systems. Mouse models have demonstrated prominent roles for proteins in the mismatch repair pathway as critical drivers of CAG/CTG instability, which is also suggested by recent genome-wide association studies in humans. We draw attention to a network of connections between modifiers identified across several systems that might indicate pathway crosstalk in the context of repeat instability, and which could provide hypotheses for further validation or discovery. Overall, the data indicate that repeat dynamics might be modulated by altering the levels of DNA metabolic proteins, their regulation, their interaction with chromatin, or by direct perturbation of the repeat tract. Applying novel methodologies and technologies to this exciting area of research will be needed to gain deeper mechanistic insight that can be harnessed for therapies aimed at preventing repeat expansion or promoting repeat contraction.
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Affiliation(s)
- Vanessa C. Wheeler
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA,Department of Neurology, Harvard Medical School, Boston, MA, USA,Correspondence to: Vanessa C. Wheeler, Center for Genomic Medicine, Massachusetts Hospital, Boston MAA 02115, USA. E-mail: . and Vincent Dion, UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, CF24 4HQ Cardiff, UK. E-mail:
| | - Vincent Dion
- UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, Cardiff, UK,Correspondence to: Vanessa C. Wheeler, Center for Genomic Medicine, Massachusetts Hospital, Boston MAA 02115, USA. E-mail: . and Vincent Dion, UK Dementia Research Institute at Cardiff University, Hadyn Ellis Building, Maindy Road, CF24 4HQ Cardiff, UK. E-mail:
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9
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Gusella JF, Lee JM, MacDonald ME. Huntington's disease: nearly four decades of human molecular genetics. Hum Mol Genet 2021; 30:R254-R263. [PMID: 34169318 PMCID: PMC8490011 DOI: 10.1093/hmg/ddab170] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/16/2021] [Accepted: 06/21/2021] [Indexed: 11/13/2022] Open
Abstract
Huntington's disease (HD) is a devastating neurogenetic disorder whose familial nature and progressive course were first described in the 19th century but for which no disease-modifying treatment is yet available. Through the active participation of HD families, this disorder has acted as a flagship for the application of human molecular genetic strategies to identify disease genes, understand pathogenesis and identify rational targets for development of therapies.
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Affiliation(s)
- James F Gusella
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA 02142, USA
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Jong-Min Lee
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA 02142, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Marcy E MacDonald
- Molecular Neurogenetics Unit, Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Medical and Population Genetics Program, The Broad Institute of M.I.T. and Harvard, Cambridge, MA 02142, USA
- Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
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10
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Zhao X, Usdin K. (Dys)function Follows Form: Nucleic Acid Structure, Repeat Expansion, and Disease Pathology in FMR1 Disorders. Int J Mol Sci 2021; 22:ijms22179167. [PMID: 34502075 PMCID: PMC8431139 DOI: 10.3390/ijms22179167] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 08/17/2021] [Accepted: 08/18/2021] [Indexed: 12/26/2022] Open
Abstract
Fragile X-related disorders (FXDs), also known as FMR1 disorders, are examples of repeat expansion diseases (REDs), clinical conditions that arise from an increase in the number of repeats in a disease-specific microsatellite. In the case of FXDs, the repeat unit is CGG/CCG and the repeat tract is located in the 5' UTR of the X-linked FMR1 gene. Expansion can result in neurodegeneration, ovarian dysfunction, or intellectual disability depending on the number of repeats in the expanded allele. A growing body of evidence suggests that the mutational mechanisms responsible for many REDs share several common features. It is also increasingly apparent that in some of these diseases the pathologic consequences of expansion may arise in similar ways. It has long been known that many of the disease-associated repeats form unusual DNA and RNA structures. This review will focus on what is known about these structures, the proteins with which they interact, and how they may be related to the causative mutation and disease pathology in the FMR1 disorders.
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Affiliation(s)
- Xiaonan Zhao
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
| | - Karen Usdin
- Correspondence: (X.Z.); (K.U.); Tel.: +1-301-451-6322 (X.Z.); +1-301-496-2189 (K.U.)
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11
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Reyes CJ, Laabs BH, Schaake S, Lüth T, Ardicoglu R, Rakovic A, Grütz K, Alvarez-Fischer D, Jamora RD, Rosales RL, Weyers I, König IR, Brüggemann N, Klein C, Dobricic V, Westenberger A, Trinh J. Brain Regional Differences in Hexanucleotide Repeat Length in X-Linked Dystonia-Parkinsonism Using Nanopore Sequencing. NEUROLOGY-GENETICS 2021; 7:e608. [PMID: 34250228 PMCID: PMC8265576 DOI: 10.1212/nxg.0000000000000608] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 06/03/2021] [Indexed: 12/14/2022]
Abstract
Objective Our study investigated the presence of regional differences in hexanucleotide repeat number in postmortem brain tissues of 2 patients with X-linked dystonia-parkinsonism (XDP), a combined dystonia-parkinsonism syndrome modified by a (CCCTCT)n repeat within the causal SINE-VNTR-Alu retrotransposon insertion in the TAF1 gene. Methods Genomic DNA was extracted from blood and postmortem brain samples, including the basal ganglia and cortex from both patients and from the cerebellum, midbrain, and pituitary gland from 1 patient. Repeat sizing was performed using fragment analysis, small-pool PCR-based Southern blotting, and Oxford nanopore sequencing. Results The basal ganglia (p < 0.001) and cerebellum (p < 0.001) showed higher median repeat numbers and higher degrees of repeat instability compared with blood. Conclusions Somatic repeat instability may predominate in brain regions selectively affected in XDP, thereby hinting at its potential role in disease manifestation and modification.
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Affiliation(s)
- Charles Jourdan Reyes
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Björn-Hergen Laabs
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Susen Schaake
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Theresa Lüth
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Raphaela Ardicoglu
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Aleksandar Rakovic
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Karen Grütz
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Daniel Alvarez-Fischer
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Roland Dominic Jamora
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Raymond L Rosales
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Imke Weyers
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Inke R König
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Norbert Brüggemann
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Christine Klein
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Valerija Dobricic
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Ana Westenberger
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
| | - Joanne Trinh
- Institute of Neurogenetics (C.J.R., S.S., T.L., R.A., A.R., K.G., D.A.-F., N.B., C.K., V.D., A.W., J.T.), University of Lübeck, and Institute of Medical Biometry and Statistics (B.-H.L., I.R.K.), University of Lübeck, Germany; Department of Neurosciences (R.D.J.), College of Medicine-Philippine General Hospital, University of the Philippines Manila; Department of Neurology and Psychiatry (R.L.R.), University of Santo Tomas Hospital, Manila, Philippines; Institute of Anatomy (I.W.), Department of Neurology (N.B.), and Lübeck Interdisciplinary Platform for Genome Analytics (V.D.), University of Lübeck, Germany
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12
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Replication-independent instability of Friedreich's ataxia GAA repeats during chronological aging. Proc Natl Acad Sci U S A 2021; 118:2013080118. [PMID: 33495349 PMCID: PMC7865128 DOI: 10.1073/pnas.2013080118] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The inheritance of long (GAA)n repeats in the frataxin gene causes the debilitating neurodegenerative disease Friedreich’s ataxia. Subsequent expansions of these repeats throughout a patient’s lifetime in the affected tissues, like the nervous system, may contribute to disease onset. We developed an experimental model to characterize the mechanisms of repeat instability in nondividing cells to better understand how mutations can occur as cells age chronologically. We show that repeats can expand in nondividing cells. Notably, however, large deletions are the major type of repeat-mediated genome instability in nondividing cells, implicating the loss of important genetic material with aging in the progression of Friedreich’s ataxia. Nearly 50 hereditary diseases result from the inheritance of abnormally long repetitive DNA microsatellites. While it was originally believed that the size of inherited repeats is the key factor in disease development, it has become clear that somatic instability of these repeats throughout an individual’s lifetime strongly contributes to disease onset and progression. Importantly, somatic instability is commonly observed in terminally differentiated, postmitotic cells, such as neurons. To unravel the mechanisms of repeat instability in nondividing cells, we created an experimental system to analyze the mutability of Friedreich’s ataxia (GAA)n repeats during chronological aging of quiescent Saccharomyces cerevisiae. Unexpectedly, we found that the predominant repeat-mediated mutation in nondividing cells is large-scale deletions encompassing parts, or the entirety, of the repeat and adjacent regions. These deletions are caused by breakage at the repeat mediated by mismatch repair (MMR) complexes MutSβ and MutLα and DNA endonuclease Rad1, followed by end-resection by Exo1 and repair of the resulting double-strand breaks (DSBs) via nonhomologous end joining. We also observed repeat-mediated gene conversions as a result of DSB repair via ectopic homologous recombination during chronological aging. Repeat expansions accrue during chronological aging as well—particularly in the absence of MMR-induced DSBs. These expansions depend on the processivity of DNA polymerase δ while being counteracted by Exo1 and MutSβ, implicating nick repair. Altogether, these findings show that the mechanisms and types of (GAA)n repeat instability differ dramatically between dividing and nondividing cells, suggesting that distinct repeat-mediated mutations in terminally differentiated somatic cells might influence Friedreich’s ataxia pathogenesis.
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13
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Venkatasamy L, Nizamutdinov D, Jenkins J, Shapiro LA. Vagus Nerve Stimulation Ameliorates Cognitive Impairment and Increased Hippocampal Astrocytes in a Mouse Model of Gulf War Illness. Neurosci Insights 2021; 16:26331055211018456. [PMID: 34104886 PMCID: PMC8165814 DOI: 10.1177/26331055211018456] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 04/29/2021] [Indexed: 01/17/2023] Open
Abstract
Gulf war illness (GWI), is a chronic multi-symptom illness that has impacted approximately one-third of the veterans who served in the 1990 to 1991 Gulf War. GWI symptoms include cognitive impairments (eg, memory and concentration problems), headaches, migraines, fatigue, gastrointestinal and respiratory issues, as well as emotional deficits. The exposure to neurological chemicals such as the anti-nerve gas drug, pyridostigmine bromide (PB), and the insecticide permethrin (PER), may contribute to the etiologically related factors of GWI. Various studies utilizing mouse models of GWI have reported the interplay of these chemical agents in increasing neuroinflammation and cognitive dysfunction. Astrocytes are involved in the secretion of neuroinflammatory cytokines and chemokines in pathological conditions and have been implicated in GWI symptomology. We hypothesized that exposure to PB and PER causes lasting changes to hippocampal astrocytes, concurrent with chronic cognitive deficits that can be reversed by cervical vagus nerve stimulation (VNS). GWI was induced in CD1 mice by injecting the mixture of PER (200 mg/kg) and PB (2 mg/kg), i.p. for 10 consecutive days. VNS stimulators were implanted at 33 weeks after GWI induction. The results show age-related cognitive alterations at approximately 9 months after exposure to PB and PER. The results also showed an increased number of GFAP-labeled astrocytes in the hippocampus and dentate gyrus that was ameliorated by VNS.
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Affiliation(s)
- Lavanya Venkatasamy
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University, Bryan, TX, USA
| | - Damir Nizamutdinov
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University, Bryan, TX, USA
| | - Jaclyn Jenkins
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University, Bryan, TX, USA
| | - Lee A Shapiro
- Department of Neuroscience and Experimental Therapeutics, Texas A&M University, Bryan, TX, USA
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14
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Molecular Basis of Neuronal Autophagy in Ageing: Insights from Caenorhabditis elegans. Cells 2021; 10:cells10030694. [PMID: 33800981 PMCID: PMC8004021 DOI: 10.3390/cells10030694] [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: 02/28/2021] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/19/2023] Open
Abstract
Autophagy is an evolutionarily conserved degradation process maintaining cell homeostasis. Induction of autophagy is triggered as a response to a broad range of cellular stress conditions, such as nutrient deprivation, protein aggregation, organelle damage and pathogen invasion. Macroautophagy involves the sequestration of cytoplasmic contents in a double-membrane organelle referred to as the autophagosome with subsequent degradation of its contents upon delivery to lysosomes. Autophagy plays critical roles in development, maintenance and survival of distinct cell populations including neurons. Consequently, age-dependent decline in autophagy predisposes animals for age-related diseases including neurodegeneration and compromises healthspan and longevity. In this review, we summarize recent advances in our understanding of the role of neuronal autophagy in ageing, focusing on studies in the nematode Caenorhabditis elegans.
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15
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Monckton DG. The Contribution of Somatic Expansion of the CAG Repeat to Symptomatic Development in Huntington's Disease: A Historical Perspective. J Huntingtons Dis 2021; 10:7-33. [PMID: 33579863 PMCID: PMC7990401 DOI: 10.3233/jhd-200429] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery in the early 1990s of the expansion of unstable simple sequence repeats as the causative mutation for a number of inherited human disorders, including Huntington’s disease (HD), opened up a new era of human genetics and provided explanations for some old problems. In particular, an inverse association between the number of repeats inherited and age at onset, and unprecedented levels of germline instability, biased toward further expansion, provided an explanation for the wide symptomatic variability and anticipation observed in HD and many of these disorders. The repeats were also revealed to be somatically unstable in a process that is expansion-biased, age-dependent and tissue-specific, features that are now increasingly recognised as contributory to the age-dependence, progressive nature and tissue specificity of the symptoms of HD, and at least some related disorders. With much of the data deriving from affected individuals, and model systems, somatic expansions have been revealed to arise in a cell division-independent manner in critical target tissues via a mechanism involving key components of the DNA mismatch repair pathway. These insights have opened new approaches to thinking about how the disease could be treated by suppressing somatic expansion and revealed novel protein targets for intervention. Exciting times lie ahead in turning these insights into novel therapies for HD and related disorders.
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Affiliation(s)
- Darren G Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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16
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Zhao X, Kumari D, Miller CJ, Kim GY, Hayward B, Vitalo AG, Pinto RM, Usdin K. Modifiers of Somatic Repeat Instability in Mouse Models of Friedreich Ataxia and the Fragile X-Related Disorders: Implications for the Mechanism of Somatic Expansion in Huntington's Disease. J Huntingtons Dis 2021; 10:149-163. [PMID: 33579860 PMCID: PMC7990428 DOI: 10.3233/jhd-200423] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Huntington's disease (HD) is one of a large group of human disorders that are caused by expanded DNA repeats. These repeat expansion disorders can have repeat units of different size and sequence that can be located in any part of the gene and, while the pathological consequences of the expansion can differ widely, there is evidence to suggest that the underlying mutational mechanism may be similar. In the case of HD, the expanded repeat unit is a CAG trinucleotide located in exon 1 of the huntingtin (HTT) gene, resulting in an expanded polyglutamine tract in the huntingtin protein. Expansion results in neuronal cell death, particularly in the striatum. Emerging evidence suggests that somatic CAG expansion, specifically expansion occurring in the brain during the lifetime of an individual, contributes to an earlier disease onset and increased severity. In this review we will discuss mouse models of two non-CAG repeat expansion diseases, specifically the Fragile X-related disorders (FXDs) and Friedreich ataxia (FRDA). We will compare and contrast these models with mouse and patient-derived cell models of various other repeat expansion disorders and the relevance of these findings for somatic expansion in HD. We will also describe additional genetic factors and pathways that modify somatic expansion in the FXD mouse model for which no comparable data yet exists in HD mice or humans. These additional factors expand the potential druggable space for diseases like HD where somatic expansion is a significant contributor to disease impact.
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Affiliation(s)
- Xiaonan Zhao
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Daman Kumari
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Carson J Miller
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Geum-Yi Kim
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Bruce Hayward
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Antonia G Vitalo
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA
| | - Ricardo Mouro Pinto
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA.,Department of Neurology, Harvard Medical School, Boston, MA, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Karen Usdin
- Laboratory of Cell and Molecular Biology, National Institutes of Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
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17
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Gomes-Pereira M, Monckton DG. Chronic Exposure to Cadmium and Antioxidants Does Not Affect the Dynamics of Expanded CAG•CTG Trinucleotide Repeats in a Mouse Cell Culture System of Unstable DNA. Front Cell Neurosci 2021; 14:606331. [PMID: 33603644 PMCID: PMC7884634 DOI: 10.3389/fncel.2020.606331] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/29/2020] [Indexed: 12/02/2022] Open
Abstract
More than 30 human disorders are caused by the expansion of simple sequence DNA repeats, among which triplet repeats remain the most frequent. Most trinucleotide repeat expansion disorders affect primarily the nervous system, through mechanisms of neurodysfunction and/or neurodegeneration. While trinucleotide repeat tracts are short and stably transmitted in unaffected individuals, disease-associated expansions are highly dynamic in the germline and in somatic cells, with a tendency toward further expansion. Since longer repeats are associated with increasing disease severity and earlier onset of symptoms, intergenerational repeat size gains account for the phenomenon of anticipation. In turn, higher levels of age-dependent somatic expansion have been linked with increased disease severity and earlier age of onset, implicating somatic instability in the onset and progression of disease symptoms. Hence, tackling the root cause of symptoms through the control of repeat dynamics may provide therapeutic modulation of clinical manifestations. DNA repair pathways have been firmly implicated in the molecular mechanism of repeat length mutation. The demonstration that repeat expansion depends on functional DNA mismatch repair (MMR) proteins, points to MMR as a potential therapeutic target. Similarly, a role of DNA base excision repair (BER) in repeat expansion has also been suggested, particularly during the removal of oxidative lesions. Using a well-characterized mouse cell model system of an unstable CAG•CTG trinucleotide repeat, we tested if expanded repeat tracts can be stabilized by small molecules with reported roles in both pathways: cadmium (an inhibitor of MMR activity) and a variety of antioxidants (capable of neutralizing oxidative species). We found that chronic exposure to sublethal doses of cadmium and antioxidants did not result in significant reduction of the rate of trinucleotide repeat expansion. Surprisingly, manganese yielded a significant stabilization of the triplet repeat tract. We conclude that treatment with cadmium and antioxidants, at doses that do not interfere with cell survival and cell culture dynamics, is not sufficient to modify trinucleotide repeat dynamics in cell culture.
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Affiliation(s)
| | - Darren G Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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18
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Nakamori M, Mochizuki H. Targeting Expanded Repeats by Small Molecules in Repeat Expansion Disorders. Mov Disord 2020; 36:298-305. [DOI: 10.1002/mds.28397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Masayuki Nakamori
- Department of Neurology Osaka University Graduate School of Medicine Osaka Japan
| | - Hideki Mochizuki
- Department of Neurology Osaka University Graduate School of Medicine Osaka Japan
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New developments in Huntington's disease and other triplet repeat diseases: DNA repair turns to the dark side. Neuronal Signal 2020; 4:NS20200010. [PMID: 33224521 PMCID: PMC7672267 DOI: 10.1042/ns20200010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 02/08/2023] Open
Abstract
Huntington’s disease (HD) is a fatal, inherited neurodegenerative disease that causes neuronal death, particularly in medium spiny neurons. HD leads to serious and progressive motor, cognitive and psychiatric symptoms. Its genetic basis is an expansion of the CAG triplet repeat in the HTT gene, leading to extra glutamines in the huntingtin protein. HD is one of nine genetic diseases in this polyglutamine (polyQ) category, that also includes a number of inherited spinocerebellar ataxias (SCAs). Traditionally it has been assumed that HD age of onset and disease progression were solely the outcome of age-dependent exposure of neurons to toxic effects of the inherited mutant huntingtin protein. However, recent genome-wide association studies (GWAS) have revealed significant effects of genetic variants outside of HTT. Surprisingly, these variants turn out to be mostly in genes encoding DNA repair factors, suggesting that at least some disease modulation occurs at the level of the HTT DNA itself. These DNA repair proteins are known from model systems to promote ongoing somatic CAG repeat expansions in tissues affected by HD. Thus, for triplet repeats, some DNA repair proteins seem to abandon their normal genoprotective roles and, instead, drive expansions and accelerate disease. One attractive hypothesis—still to be proven rigorously—is that somatic HTT expansions augment the disease burden of the inherited allele. If so, therapeutic approaches that lower levels of huntingtin protein may need blending with additional therapies that reduce levels of somatic CAG repeat expansions to achieve maximal effect.
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20
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Machiela E, Jeloka R, Caron NS, Mehta S, Schmidt ME, Baddeley HJE, Tom CM, Polturi N, Xie Y, Mattis VB, Hayden MR, Southwell AL. The Interaction of Aging and Cellular Stress Contributes to Pathogenesis in Mouse and Human Huntington Disease Neurons. Front Aging Neurosci 2020; 12:524369. [PMID: 33192449 PMCID: PMC7531251 DOI: 10.3389/fnagi.2020.524369] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 08/18/2020] [Indexed: 12/26/2022] Open
Abstract
Huntington disease (HD) is a fatal, inherited neurodegenerative disorder caused by a mutation in the huntingtin (HTT) gene. While mutant HTT is present ubiquitously throughout life, HD onset typically occurs in mid-life. Oxidative damage accumulates in the aging brain and is a feature of HD. We sought to interrogate the roles and interaction of age and oxidative stress in HD using primary Hu97/18 mouse neurons, neurons differentiated from HD patient induced pluripotent stem cells (iPSCs), and the brains of HD mice. We find that primary neurons must be matured in culture for canonical stress responses to occur. Furthermore, when aging is accelerated in mature HD neurons, mutant HTT accumulates and sensitivity to oxidative stress is selectively enhanced. Furthermore, we observe HD-specific phenotypes in neurons and mouse brains that have undergone accelerated aging, including a selective increase in DNA damage. These findings suggest a role for aging in HD pathogenesis and an interaction between the biological age of HD neurons and sensitivity to exogenous stress.
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Affiliation(s)
- Emily Machiela
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Ritika Jeloka
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Nicholas S. Caron
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Shagun Mehta
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Mandi E. Schmidt
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Helen J. E. Baddeley
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Colton M. Tom
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Nalini Polturi
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Yuanyun Xie
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
| | - Virginia B. Mattis
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Michael R. Hayden
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
| | - Amber L. Southwell
- Burnett School of Biomedical Sciences, University of Central Florida, Orlando, FL, United States
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC, Canada
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21
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Mechetin GV, Endutkin AV, Diatlova EA, Zharkov DO. Inhibitors of DNA Glycosylases as Prospective Drugs. Int J Mol Sci 2020; 21:ijms21093118. [PMID: 32354123 PMCID: PMC7247160 DOI: 10.3390/ijms21093118] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 12/22/2022] Open
Abstract
DNA glycosylases are enzymes that initiate the base excision repair pathway, a major biochemical process that protects the genomes of all living organisms from intrinsically and environmentally inflicted damage. Recently, base excision repair inhibition proved to be a viable strategy for the therapy of tumors that have lost alternative repair pathways, such as BRCA-deficient cancers sensitive to poly(ADP-ribose)polymerase inhibition. However, drugs targeting DNA glycosylases are still in development and so far have not advanced to clinical trials. In this review, we cover the attempts to validate DNA glycosylases as suitable targets for inhibition in the pharmacological treatment of cancer, neurodegenerative diseases, chronic inflammation, bacterial and viral infections. We discuss the glycosylase inhibitors described so far and survey the advances in the assays for DNA glycosylase reactions that may be used to screen pharmacological libraries for new active compounds.
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Affiliation(s)
- Grigory V. Mechetin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (G.V.M.); (A.V.E.); (E.A.D.)
| | - Anton V. Endutkin
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (G.V.M.); (A.V.E.); (E.A.D.)
| | - Evgeniia A. Diatlova
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (G.V.M.); (A.V.E.); (E.A.D.)
| | - Dmitry O. Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., 630090 Novosibirsk, Russia; (G.V.M.); (A.V.E.); (E.A.D.)
- Novosibirsk State University, 2 Pirogova St., 630090 Novosibirsk, Russia
- Correspondence: ; Tel.: +7-383-363-5187
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22
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Rieux C, Goffinont S, Coste F, Tber Z, Cros J, Roy V, Guérin M, Gaudon V, Bourg S, Biela A, Aucagne V, Agrofoglio L, Garnier N, Castaing B. Thiopurine Derivative-Induced Fpg/Nei DNA Glycosylase Inhibition: Structural, Dynamic and Functional Insights. Int J Mol Sci 2020; 21:ijms21062058. [PMID: 32192183 PMCID: PMC7139703 DOI: 10.3390/ijms21062058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 03/12/2020] [Accepted: 03/14/2020] [Indexed: 02/06/2023] Open
Abstract
DNA glycosylases are emerging as relevant pharmacological targets in inflammation, cancer and neurodegenerative diseases. Consequently, the search for inhibitors of these enzymes has become a very active research field. As a continuation of previous work that showed that 2-thioxanthine (2TX) is an irreversible inhibitor of zinc finger (ZnF)-containing Fpg/Nei DNA glycosylases, we designed and synthesized a mini-library of 2TX-derivatives (TXn) and evaluated their ability to inhibit Fpg/Nei enzymes. Among forty compounds, four TXn were better inhibitors than 2TX for Fpg. Unexpectedly, but very interestingly, two dithiolated derivatives more selectively and efficiently inhibit the zincless finger (ZnLF)-containing enzymes (human and mimivirus Neil1 DNA glycosylases hNeil1 and MvNei1, respectively). By combining chemistry, biochemistry, mass spectrometry, blind and flexible docking and X-ray structure analysis, we localized new TXn binding sites on Fpg/Nei enzymes. This endeavor allowed us to decipher at the atomic level the mode of action for the best TXn inhibitors on the ZnF-containing enzymes. We discovered an original inhibition mechanism for the ZnLF-containing Fpg/Nei DNA glycosylases by disulfide cyclic trimeric forms of dithiopurines. This work paves the way for the design and synthesis of a new structural class of inhibitors for selective pharmacological targeting of hNeil1 in cancer and neurodegenerative diseases.
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Affiliation(s)
- Charlotte Rieux
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Stéphane Goffinont
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Franck Coste
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Zahira Tber
- Institut de Chimie Organique et Analytique, UMR7311 CNRS-Orleans University, Université d’Orléans, Pôle de Chimie, rue de Chartres, F-45100 Orléans, France; (Z.T.); (S.B.); (L.A.)
| | - Julien Cros
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Vincent Roy
- Institut de Chimie Organique et Analytique, UMR7311 CNRS-Orleans University, Université d’Orléans, Pôle de Chimie, rue de Chartres, F-45100 Orléans, France; (Z.T.); (S.B.); (L.A.)
- Université d’Orléans, UFR Sciences et Techniques, rue de Chartres, 45100 Orléans, France
- Correspondence: (V.R.); (N.G.); (B.C.)
| | - Martine Guérin
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
- Université d’Orléans, UFR Sciences et Techniques, rue de Chartres, 45100 Orléans, France
| | - Virginie Gaudon
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Stéphane Bourg
- Institut de Chimie Organique et Analytique, UMR7311 CNRS-Orleans University, Université d’Orléans, Pôle de Chimie, rue de Chartres, F-45100 Orléans, France; (Z.T.); (S.B.); (L.A.)
| | - Artur Biela
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Vincent Aucagne
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
| | - Luigi Agrofoglio
- Institut de Chimie Organique et Analytique, UMR7311 CNRS-Orleans University, Université d’Orléans, Pôle de Chimie, rue de Chartres, F-45100 Orléans, France; (Z.T.); (S.B.); (L.A.)
- Université d’Orléans, UFR Sciences et Techniques, rue de Chartres, 45100 Orléans, France
| | - Norbert Garnier
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
- Université d’Orléans, UFR Sciences et Techniques, rue de Chartres, 45100 Orléans, France
- Correspondence: (V.R.); (N.G.); (B.C.)
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, UPR4301 CNRS, rue Charles Sadron, CEDEX 2, F-45071 Orléans, France; (C.R.); (S.G.); (F.C.); (J.C.); (M.G.); (V.G.); (A.B.); (V.A.)
- Correspondence: (V.R.); (N.G.); (B.C.)
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23
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Franklin A, Steele EJ, Lindley RA. A proposed reverse transcription mechanism for (CAG)n and similar expandable repeats that cause neurological and other diseases. Heliyon 2020; 6:e03258. [PMID: 32140575 PMCID: PMC7044655 DOI: 10.1016/j.heliyon.2020.e03258] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 09/26/2019] [Accepted: 01/15/2020] [Indexed: 12/12/2022] Open
Abstract
The mechanism of (CAG)n repeat generation, and related expandable repeat diseases in non-dividing cells, is currently understood in terms of a DNA template-based DNA repair synthesis process involving hairpin stabilized slippage, local error-prone repair via MutSβ (MSH2-MSH3) hairpin protective stabilization, then nascent strand extension by DNA polymerases-β and -δ. We advance a very similar slipped hairpin-stabilized model involving MSH2-MSH3 with two key differences: the copying template may also be the nascent pre-mRNA with the repair pathway being mediated by the Y-family error-prone enzymes DNA polymerase-η and DNA polymerase-κ acting as reverse transcriptases. We argue that both DNA-based and RNA-based mechanisms could well be activated in affected non-dividing brain cells in vivo. Here, we compare the advantages of the RNA/RT-based model proposed by us as an adjunct to previously proposed models. In brief, our model depends upon dysregulated innate and adaptive immunity cascades involving AID/APOBEC and ADAR deaminases that are known to be involved in normal locus-specific immunoglobulin somatic hypermutation, cancer progression and somatic mutations at many off-target non-immunoglobulin sites across the genome: we explain how these processes could also play an active role in repeat expansion diseases at RNA polymerase II-transcribed genes.
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Affiliation(s)
- Andrew Franklin
- Medical Department, Novartis Pharmaceuticals UK Limited, 200 Frimley Business Park, Frimley, Surrey, GU16 7SR, United Kingdom
| | - Edward J. Steele
- Melville Analytics Pty Ltd, Melbourne, Vic, 3004, Australia
- CYO’Connor ERADE Village Foundation, Perth, WA, Australia
| | - Robyn A. Lindley
- GMDxgenomics, Melbourne, Vic, Australia
- Department of Clinical Pathology, Faculty of Medicine, Dentistry & Health Sciences, University of Melbourne, Vic, Australia
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24
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Nakamori M, Panigrahi GB, Lanni S, Gall-Duncan T, Hayakawa H, Tanaka H, Luo J, Otabe T, Li J, Sakata A, Caron MC, Joshi N, Prasolava T, Chiang K, Masson JY, Wold MS, Wang X, Lee MYWT, Huddleston J, Munson KM, Davidson S, Layeghifard M, Edward LM, Gallon R, Santibanez-Koref M, Murata A, Takahashi MP, Eichler EE, Shlien A, Nakatani K, Mochizuki H, Pearson CE. A slipped-CAG DNA-binding small molecule induces trinucleotide-repeat contractions in vivo. Nat Genet 2020; 52:146-159. [PMID: 32060489 PMCID: PMC7043212 DOI: 10.1038/s41588-019-0575-8] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 12/19/2019] [Indexed: 01/07/2023]
Abstract
In many repeat diseases, such as Huntington's disease (HD), ongoing repeat expansions in affected tissues contribute to disease onset, progression and severity. Inducing contractions of expanded repeats by exogenous agents is not yet possible. Traditional approaches would target proteins driving repeat mutations. Here we report a compound, naphthyridine-azaquinolone (NA), that specifically binds slipped-CAG DNA intermediates of expansion mutations, a previously unsuspected target. NA efficiently induces repeat contractions in HD patient cells as well as en masse contractions in medium spiny neurons of HD mouse striatum. Contractions are specific for the expanded allele, independently of DNA replication, require transcription across the coding CTG strand and arise by blocking repair of CAG slip-outs. NA-induced contractions depend on active expansions driven by MutSβ. NA injections in HD mouse striatum reduce mutant HTT protein aggregates, a biomarker of HD pathogenesis and severity. Repeat-structure-specific DNA ligands are a novel avenue to contract expanded repeats.
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Affiliation(s)
- Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Gagan B Panigrahi
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Stella Lanni
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Terence Gall-Duncan
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Hideki Hayakawa
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Hana Tanaka
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Jennifer Luo
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Takahiro Otabe
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Jinxing Li
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Akihiro Sakata
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Marie-Christine Caron
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Quebec, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec, Quebec, Canada
| | - Niraj Joshi
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Quebec, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec, Quebec, Canada
| | - Tanya Prasolava
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Karen Chiang
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
- Program of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Jean-Yves Masson
- Genome Stability Laboratory, CHU de Québec Research Center, HDQ Pavilion, Oncology Division, Quebec, Quebec, Canada
- Department of Molecular Biology, Medical Biochemistry and Pathology, Laval University Cancer Research Center, Quebec, Quebec, Canada
| | - Marc S Wold
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Xiaoxiao Wang
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, USA
| | - Marietta Y W T Lee
- Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla, NY, USA
| | - John Huddleston
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Katherine M Munson
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Scott Davidson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Mehdi Layeghifard
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Lisa-Monique Edward
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Richard Gallon
- Institute of Genetic Medicine, Newcastle University, Newcastle upon Tyne, UK
| | | | - Asako Murata
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Masanori P Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Evan E Eichler
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
- Howard Hughes Medical Institute, University of Washington, Seattle, WA, USA
| | - Adam Shlien
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada
| | - Kazuhiko Nakatani
- Department of Regulatory Bioorganic Chemistry, The Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Christopher E Pearson
- Program of Genetics & Genome Biology, The Hospital for Sick Children, The Peter Gilgan Centre for Research and Learning, Toronto, Ontario, Canada.
- Program of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada.
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25
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Abstract
Huntington's disease (HD) is a fatal, inherited neurodegenerative disorder caused by a mutation in the huntingtin gene (HTT). While mutant HTT is present ubiquitously throughout life, HD onset typically occurs in mid-life, suggesting that aging may play an active role in pathogenesis. Cellular aging is defined as the slow decline in stress resistance and accumulation of damage over time. While different cells and tissues can age at different rates, 9 hallmarks of aging have emerged to better define the cellular aging process. Strikingly, many of the hallmarks of aging are also hallmarks of HD pathology. Models of HD and HD patients possess markers of accelerated aging, and processes that decline during aging also decline at a more rapid rate in HD, further implicating the role of aging in HD pathogenesis. Furthermore, accelerating aging in HD mouse and patient-derived neurons unmasks HD-specific phenotypes, suggesting an active role for the aging process in the onset and progression of HD. Here, we review the overlap between the hallmarks of aging and HD and discuss how aging may contribute to pathogenesis in HD.
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Affiliation(s)
- Emily Machiela
- University of Central Florida, College of Medicine, Burnett School of Biomedical Sciences, Orlando, FL, USA
| | - Amber L. Southwell
- University of Central Florida, College of Medicine, Burnett School of Biomedical Sciences, Orlando, FL, USA
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26
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Cheon SY, Kim H, Rubinsztein DC, Lee JE. Autophagy, Cellular Aging and Age-related Human Diseases. Exp Neurobiol 2019; 28:643-657. [PMID: 31902153 PMCID: PMC6946111 DOI: 10.5607/en.2019.28.6.643] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 11/04/2019] [Accepted: 11/04/2019] [Indexed: 12/22/2022] Open
Abstract
Macroautophagy/autophagy is a conserved degradation system that engulfs intracytoplasmic contents, including aggregated proteins and organelles, which is crucial for cellular homeostasis. During aging, cellular factors suggested as the cause of aging have been reported to be associated with progressively compromised autophagy. Dysfunctional autophagy may contribute to age-related diseases, such as neurodegenerative disease, cancer, and metabolic syndrome, in the elderly. Therefore, restoration of impaired autophagy to normal may help to prevent age-related disease and extend lifespan and longevity. Therefore, this review aims to provide an overview of the mechanisms of autophagy underlying cellular aging and the consequent disease. Understanding the mechanisms of autophagy may provide potential information to aid therapeutic interventions in age-related diseases.
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Affiliation(s)
- So Yeong Cheon
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge CB2 0XY, United Kingdom.,Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea
| | - Hyunjeong Kim
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge CB2 0XY, United Kingdom.,Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea
| | - David C Rubinsztein
- Department of Medical Genetics, Cambridge Institute for Medical Research (CIMR), University of Cambridge, Cambridge CB2 0XY, United Kingdom.,UK Dementia Research Institute, University of Cambridge, Cambridge CB2 0AH, United Kingdom
| | - Jong Eun Lee
- Department of Anatomy, Yonsei University College of Medicine, Seoul 03722, Korea.,BK21 PLUS Project for Medical Science, and Brain Research Institute, Yonsei University College of Medicine, Seoul 03722, Korea
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27
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Eyk CLV, Samaraweera SE, Scott A, Webber DL, Harvey DP, Mecinger O, O’Keefe LV, Cropley JE, Young P, Ho J, Suter C, Richards RI. Non-self mutation: double-stranded RNA elicits antiviral pathogenic response in a Drosophila model of expanded CAG repeat neurodegenerative diseases. Hum Mol Genet 2019; 28:3000-3012. [DOI: 10.1093/hmg/ddz096] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 04/11/2019] [Accepted: 05/06/2019] [Indexed: 12/16/2022] Open
Abstract
Abstract
Inflammation is activated prior to symptoms in neurodegenerative diseases, providing a plausible pathogenic mechanism. Indeed, genetic and pharmacological ablation studies in animal models of several neurodegenerative diseases demonstrate that inflammation is required for pathology. However, while there is growing evidence that inflammation-mediated pathology may be the common mechanism underlying neurodegenerative diseases, including those due to dominantly inherited expanded repeats, the proximal causal agent is unknown. Expanded CAG.CUG repeat double-stranded RNA causes inflammation-mediated pathology when expressed in Drosophila. Repeat dsRNA is recognized by Dicer-2 as a foreign or ‘non-self’ molecule triggering both antiviral RNA and RNAi pathways. Neither of the RNAi pathway cofactors R2D2 nor loquacious are necessary, indicating antiviral RNA activation. RNA modification enables avoidance of recognition as ‘non-self’ by the innate inflammatory surveillance system. Human ADAR1 edits RNA conferring ‘self’ status and when co-expressed with expanded CAG.CUG dsRNA in Drosophila the pathology is lost. Cricket Paralysis Virus protein CrPV-1A is a known antagonist of Argonaute-2 in Drosophila antiviral defense. CrPV-1A co-expression also rescues pathogenesis, confirming anti-viral-RNA response. Repeat expansion mutation therefore confers ‘non-self’ recognition of endogenous RNA, thereby providing a proximal, autoinflammatory trigger for expanded repeat neurodegenerative diseases.
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Affiliation(s)
- Clare L van Eyk
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Saumya E Samaraweera
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Andrew Scott
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Dani L Webber
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - David P Harvey
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Olivia Mecinger
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Louise V O’Keefe
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
| | - Jennifer E Cropley
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Liverpool St, Darlinghurst, Sydney 2010, Australia
- Faculty of Medicine, University of New South Wales, Kensington, New South Wales 2042, Australia
| | - Paul Young
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Liverpool St, Darlinghurst, Sydney 2010, Australia
- Faculty of Medicine, University of New South Wales, Kensington, New South Wales 2042, Australia
| | - Joshua Ho
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Liverpool St, Darlinghurst, Sydney 2010, Australia
- Faculty of Medicine, University of New South Wales, Kensington, New South Wales 2042, Australia
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong
| | - Catherine Suter
- Victor Chang Cardiac Research Institute, Lowy Packer Building, Liverpool St, Darlinghurst, Sydney 2010, Australia
- Faculty of Medicine, University of New South Wales, Kensington, New South Wales 2042, Australia
| | - Robert I Richards
- Department of Molecular and Biomedical Science, School of Biological Sciences, The University of Adelaide, Adelaide, South Australia 5000, Australia
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28
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Repeat Instability in the Fragile X-Related Disorders: Lessons from a Mouse Model. Brain Sci 2019; 9:brainsci9030052. [PMID: 30832215 PMCID: PMC6468611 DOI: 10.3390/brainsci9030052] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Revised: 02/21/2019] [Accepted: 02/27/2019] [Indexed: 12/21/2022] Open
Abstract
The fragile X-related disorders (FXDs) are a group of clinical conditions that result primarily from an unusual mutation, the expansion of a CGG-repeat tract in exon 1 of the FMR1 gene. Mouse models are proving useful for understanding many aspects of disease pathology in these disorders. There is also reason to think that such models may be useful for understanding the molecular basis of the unusual mutation responsible for these disorders. This review will discuss what has been learnt to date about mechanisms of repeat instability from a knock-in FXD mouse model and what the implications of these findings may be for humans carrying expansion-prone FMR1 alleles.
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29
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Kullmann FA, McDonnell BM, Wolf-Johnston AS, Kanai AJ, Shiva S, Chelimsky T, Rodriguez L, Birder LA. Stress-induced autonomic dysregulation of mitochondrial function in the rat urothelium. Neurourol Urodyn 2019; 38:572-581. [PMID: 30575113 PMCID: PMC7528980 DOI: 10.1002/nau.23876] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Accepted: 10/10/2018] [Indexed: 12/27/2022]
Abstract
AIM Chronic stress exacerbates the symptoms of most pain disorders including interstitial cystitis/bladder pain syndrome (IC/BPS). Abnormalities in urothelial cells (UTC) occur in this debilitating bladder condition. The sequence of events that might link stress (presumably through increased sympathetic nervous system-SNS activity) to urothelial dysfunction are unknown. Since autonomic dysregulation, mitochondrial dysfunction, and oxidative stress all occur in chronic pain, we investigated whether chronic psychological stress initiated a cascade linking these three dysfunctions. METHODS Adult female Wistar Kyoto rats were exposed to 10 days of water avoidance stress (WAS). Bladders were then harvested for Western blot and single cell imaging in UTC cultures. RESULTS UTC from WAS rats exhibited depolarized mitochondria membrane potential (Ψm ∼30% more depolarized compared to control), activated AMPK and altered UT mitochondria bioenergetics. Expression of the fusion protein mitofusion-2 (MFN-2) was upregulated in the mucosa, suggesting mitochondrial structural changes consistent with altered cellular metabolism. Intracellular calcium levels were elevated in cultured WAS UTC, consistent with impaired cellular function. Stimulation of cultured UTC with alpha-adrenergic (α-AR) receptor agonists increased reactive oxidative species (ROS) production, suggesting a direct action of SNS activity on UTC. Treatment of rats with guanethidine to block SNS activity prevented most of WAS-induced changes. CONCLUSIONS Chronic stress results in persistent sympathetically mediated effects that alter UTC mitochondrial function. This may impact the urothelial barrier and signaling, which contributes to bladder dysfunction and pain. This is the first demonstration, to our knowledge, of a potential autonomic mechanism directly linking stress to mitochondrial dysfunction.
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Affiliation(s)
- Florenta Aura Kullmann
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Bronagh M. McDonnell
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Amanda S. Wolf-Johnston
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Anthony J. Kanai
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Sruti Shiva
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Thomas Chelimsky
- Department of Neurology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Larissa Rodriguez
- Departments of Urology and Obstetrics and Gynecology, University of Southern California, Los Angeles, California
| | - Lori A. Birder
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania,Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
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30
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Pešović J, Perić S, Brkušanin M, Brajušković G, Rakočević-Stojanović V, Savić-Pavićević D. Repeat Interruptions Modify Age at Onset in Myotonic Dystrophy Type 1 by Stabilizing DMPK Expansions in Somatic Cells. Front Genet 2018; 9:601. [PMID: 30546383 PMCID: PMC6278776 DOI: 10.3389/fgene.2018.00601] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 11/15/2018] [Indexed: 12/19/2022] Open
Abstract
CTG expansions in DMPK gene, causing myotonic dystrophy type 1 (DM1), are characterized by pronounced somatic instability. A large proportion of variability of somatic instability is explained by expansion size and patient's age at sampling, while individual-specific differences are attributed to additional factors. The age at onset is extremely variable in DM1, and inversely correlates with the expansion size and individual-specific differences in somatic instability. Three to five percent of DM1 patients carry repeat interruptions and some appear with later age at onset than expected for corresponding expansion size. Herein, we characterized somatic instability of interrupted DMPK expansions and the effect on age at onset in our previously described patients. Repeat-primed PCR showed stable structures of different types and patterns of repeat interruptions in blood cells over time and buccal cells. Single-molecule small-pool PCR quantification of somatic instability and mathematical modeling showed that interrupted expansions were characterized by lower level of somatic instability accompanied by slower progression over time. Mathematical modeling demonstrated that individual-specific differences in somatic instability had greater influence on age at onset in patients with interrupted expansions. Therefore, repeat interruptions have clinical importance for disease course in DM1 patients due to stabilizing effect on DMPK expansions in somatic cells.
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Affiliation(s)
- Jovan Pešović
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Stojan Perić
- School of Medicine, University of Belgrade, Belgrade, Serbia.,Neurology Clinic, Clinical Center of Serbia, Belgrade, Serbia
| | - Miloš Brkušanin
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Goran Brajušković
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
| | - Vidosava Rakočević-Stojanović
- School of Medicine, University of Belgrade, Belgrade, Serbia.,Neurology Clinic, Clinical Center of Serbia, Belgrade, Serbia
| | - Dušanka Savić-Pavićević
- Center for Human Molecular Genetics, Faculty of Biology, University of Belgrade, Belgrade, Serbia
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31
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Askeland G, Rodinova M, Štufková H, Dosoudilova Z, Baxa M, Smatlikova P, Bohuslavova B, Klempir J, Nguyen TD, Kuśnierczyk A, Bjørås M, Klungland A, Hansikova H, Ellederova Z, Eide L. A transgenic minipig model of Huntington's disease shows early signs of behavioral and molecular pathologies. Dis Model Mech 2018; 11:dmm.035949. [PMID: 30254085 PMCID: PMC6215428 DOI: 10.1242/dmm.035949] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 09/12/2018] [Indexed: 12/11/2022] Open
Abstract
Huntington's disease (HD) is a monogenic, progressive, neurodegenerative disorder with currently no available treatment. The Libechov transgenic minipig model for HD (TgHD) displays neuroanatomical similarities to humans and exhibits slow disease progression, and is therefore more powerful than available mouse models for the development of therapy. The phenotypic characterization of this model is still ongoing, and it is essential to validate biomarkers to monitor disease progression and intervention. In this study, the behavioral phenotype (cognitive, motor and behavior) of the TgHD model was assessed, along with biomarkers for mitochondrial capacity, oxidative stress, DNA integrity and DNA repair at different ages (24, 36 and 48 months), and compared with age-matched controls. The TgHD minipigs showed progressive accumulation of the mutant huntingtin (mHTT) fragment in brain tissue and exhibited locomotor functional decline at 48 months. Interestingly, this neuropathology progressed without any significant age-dependent changes in any of the other biomarkers assessed. Rather, we observed genotype-specific effects on mitochondrial DNA (mtDNA) damage, mtDNA copy number, 8-oxoguanine DNA glycosylase activity and global level of the epigenetic marker 5-methylcytosine that we believe is indicative of a metabolic alteration that manifests in progressive neuropathology. Peripheral blood mononuclear cells (PBMCs) were relatively spared in the TgHD minipig, probably due to the lack of detectable mHTT. Our data demonstrate that neuropathology in the TgHD model has an age of onset of 48 months, and that oxidative damage and electron transport chain impairment represent later states of the disease that are not optimal for assessing interventions. This article has an associated First Person interview with the first author of the paper. Summary: Here, we show that a minipig model of Huntington's disease mimics human neurodegeneration and holds promise for future intervention studies. However, minipig peripheral blood mononuclear cells express no detectable mutant huntingtin, eliminating their use as monitoring tools.
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Affiliation(s)
- Georgina Askeland
- Department of Medical Biochemistry, Institute of Clinical Medicine, University of Oslo, 0372 Oslo, Norway.,Department of Microbiology, Oslo University Hospital, 0372 Oslo, Norway
| | - Marie Rodinova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12808, Czech Republic
| | - Hana Štufková
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12808, Czech Republic
| | - Zaneta Dosoudilova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12808, Czech Republic
| | - Monika Baxa
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12808, Czech Republic
| | - Petra Smatlikova
- Laboratory of Cell Regeneration and Plasticity, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov 27721, Czech Republic
| | - Bozena Bohuslavova
- Laboratory of Cell Regeneration and Plasticity, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov 27721, Czech Republic.,Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague 12843, Czech Republic
| | - Jiri Klempir
- Department of Neurology and Centre of Clinical Neuroscience, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12821, Czech Republic
| | - The Duong Nguyen
- Laboratory of Cell Regeneration and Plasticity, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov 27721, Czech Republic.,Department of Cell Biology, Faculty of Science, Charles University in Prague, Prague 12843, Czech Republic
| | - Anna Kuśnierczyk
- Proteomics and Metabolomics Core Facility, PROMEC, Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Magnar Bjørås
- Department of Microbiology, Oslo University Hospital, 0372 Oslo, Norway.,Proteomics and Metabolomics Core Facility, PROMEC, Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, 7491 Trondheim, Norway
| | - Arne Klungland
- Department of Microbiology, Oslo University Hospital, 0372 Oslo, Norway
| | - Hana Hansikova
- Department of Pediatrics and Adolescent Medicine, First Faculty of Medicine, Charles University in Prague and General University Hospital in Prague, Prague 12808, Czech Republic
| | - Zdenka Ellederova
- Laboratory of Cell Regeneration and Plasticity, Institute of Animal Physiology and Genetics, Czech Academy of Science, Libechov 27721, Czech Republic
| | - Lars Eide
- Department of Medical Biochemistry, Institute of Clinical Medicine, University of Oslo, 0372 Oslo, Norway
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32
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Zhao XN, Usdin K. FAN1 protects against repeat expansions in a Fragile X mouse model. DNA Repair (Amst) 2018; 69:1-5. [PMID: 29990673 PMCID: PMC6119480 DOI: 10.1016/j.dnarep.2018.07.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/03/2018] [Accepted: 07/03/2018] [Indexed: 10/28/2022]
Abstract
The Fragile X-related disorders (FXDs) are members of a large group of human neurological or neurodevelopmental conditions known as the Repeat Expansion Diseases. The mutation responsible for all of these diseases is an expansion in the size of a disease-specific tandem repeat tract. However, the underlying cause of this unusual mutation is unknown. Genome-wide association studies have identified single nucleotide polymorphisms (SNPs) in the vicinity of the FAN1 (MIM* 613534) gene that are associated with variations in the age at onset of a number of Repeat Expansion Diseases. FAN1 is a nuclease that has both 5'-3' exonuclease and 5' flap endonuclease activities. Here we show in a model for the FXDs that Fan1-/- mice have expansions that, in some tissues including brain, are 2-3 times as extensive as they are in Fan1+/+ mice. However, no effect of the loss of FAN1 was apparent for germ line expansions. Thus, FAN1 plays an important role in protecting against somatic expansions but is either not involved in protecting against intergenerational repeat expansions or is redundant with other related enzymes. However, since loss of FAN1 results in increased expansions in brain and other somatic tissue, FAN1 polymorphisms may be important disease modifiers in those Repeat Expansion Diseases in which somatic expansion contributes to age at onset or disease severity.
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Affiliation(s)
- Xiao-Nan Zhao
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, United States.
| | - Karen Usdin
- Section on Gene Structure and Disease, Laboratory of Cell and Molecular Biology, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, United States.
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33
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Brand RM, Wipf P, Durham A, Epperly MW, Greenberger JS, Falo LD. Targeting Mitochondrial Oxidative Stress to Mitigate UV-Induced Skin Damage. Front Pharmacol 2018; 9:920. [PMID: 30177881 PMCID: PMC6110189 DOI: 10.3389/fphar.2018.00920] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 07/26/2018] [Indexed: 12/16/2022] Open
Abstract
Unmitigated UV radiation (UVR) induces skin photoaging and multiple forms of cutaneous carcinoma by complex pathways that include those mediated by UV-induced reactive oxygen species (ROS). Upon UVR exposure, a cascade of events is induced that overwhelms the skin’s natural antioxidant defenses and results in DNA damage, intracellular lipid and protein peroxidation, and the dysregulation of pathways that modulate inflammatory and apoptotic responses. To this end, natural products with potent antioxidant properties have been developed to prevent, mitigate, or reverse this damage with varying degrees of success. Mitochondria are particularly susceptible to ROS and subsequent DNA damage as they are a major intracellular source of oxidants. Therefore, the development of mitochondrially targeted agents to mitigate mitochondrial oxidative stress and resulting DNA damage is a logical approach to prevent and treat UV-induced skin damage. We summarize evidence that some existing natural products may reduce mitochondrial oxidative stress and support for synthetically generated mitochondrial targeted cyclic nitroxides as potential alternatives for the prevention and mitigation of UVR-induced skin damage.
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Affiliation(s)
- Rhonda M Brand
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Austin Durham
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States
| | - Michael W Epperly
- Department of Radiation Oncology, University of Pittsburgh, Pittsburgh, PA, United States
| | - Joel S Greenberger
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Radiation Oncology, University of Pittsburgh, Pittsburgh, PA, United States.,UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, United States
| | - Louis D Falo
- Department of Dermatology, University of Pittsburgh, Pittsburgh, PA, United States.,McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, United States.,UPMC Hillman Cancer Center, University of Pittsburgh, Pittsburgh, PA, United States.,Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States.,Clinical and Translational Science Institute, University of Pittsburgh, Pittsburgh, PA, United States
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34
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Increased nuclear DNA damage precedes mitochondrial dysfunction in peripheral blood mononuclear cells from Huntington's disease patients. Sci Rep 2018; 8:9817. [PMID: 29959348 PMCID: PMC6026140 DOI: 10.1038/s41598-018-27985-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Accepted: 06/12/2018] [Indexed: 01/08/2023] Open
Abstract
Huntington’s disease (HD) is a progressive neurodegenerative disorder primarily affecting the basal ganglia and is caused by expanded CAG repeats in the huntingtin gene. Except for CAG sizing, mitochondrial and nuclear DNA (mtDNA and nDNA) parameters have not yet proven to be representative biomarkers for disease and future therapy. Here, we identified a general suppression of genes associated with aerobic metabolism in peripheral blood mononuclear cells (PBMCs) from HD patients compared to controls. In HD, the complex II subunit SDHB was lowered although not sufficiently to affect complex II activity. Nevertheless, we found decreased level of factors associated with mitochondrial biogenesis and an associated dampening of the mitochondrial DNA damage frequency in HD, implying an early defect in mitochondrial activity. In contrast to mtDNA, nDNA from HD patients was four-fold more modified than controls and demonstrated that nDNA integrity is severely reduced in HD. Interestingly, the level of nDNA damage correlated inversely with the total functional capacity (TFC) score; an established functional score of HD. Our data show that PBMCs are a promising source to monitor HD progression and highlights nDNA damage and diverging mitochondrial and nuclear genome responses representing early cellular impairments in HD.
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35
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McGinty RJ, Mirkin SM. Cis- and Trans-Modifiers of Repeat Expansions: Blending Model Systems with Human Genetics. Trends Genet 2018; 34:448-465. [PMID: 29567336 PMCID: PMC5959756 DOI: 10.1016/j.tig.2018.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 02/15/2018] [Accepted: 02/19/2018] [Indexed: 12/30/2022]
Abstract
Over 30 hereditary diseases are caused by the expansion of microsatellite repeats. The length of the expandable repeat is the main hereditary determinant of these disorders. They are also affected by numerous genomic variants that are either nearby (cis) or physically separated from (trans) the repetitive locus, which we review here. These genetic variants have largely been elucidated in model systems using gene knockouts, while a few have been directly observed as single-nucleotide polymorphisms (SNPs) in patients. There is a notable disconnect between these two bodies of knowledge: knockouts poorly approximate the SNP-level variation in human populations that gives rise to medically relevant cis- and trans-modifiers, while the rarity of these diseases limits the statistical power of SNP-based analysis in humans. We propose that high-throughput SNP-based screening in model systems could become a useful approach to quickly identify and characterize modifiers of clinical relevance for patients.
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Affiliation(s)
- Ryan J McGinty
- Department of Biology, Tufts University, Medford, MA 02155, USA
| | - Sergei M Mirkin
- Department of Biology, Tufts University, Medford, MA 02155, USA.
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36
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Halabi A, Fuselier KTB, Grabczyk E. GAA•TTC repeat expansion in human cells is mediated by mismatch repair complex MutLγ and depends upon the endonuclease domain in MLH3 isoform one. Nucleic Acids Res 2018; 46:4022-4032. [PMID: 29529236 PMCID: PMC5934671 DOI: 10.1093/nar/gky143] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Accepted: 02/15/2018] [Indexed: 12/12/2022] Open
Abstract
DNA repeat expansion underlies dozens of progressive neurodegenerative disorders. While the mechanisms driving repeat expansion are not fully understood, increasing evidence suggests a central role for DNA mismatch repair. The mismatch repair recognition complex MutSβ (MSH2-MSH3) that binds mismatched bases and/or insertion/deletion loops has previously been implicated in GAA•TTC, CAG•CTG and CGG•CCG repeat expansion, suggesting a shared mechanism. MutSβ has been studied in a number of models, but the contribution of subsequent steps mediated by the MutL endonuclease in this pathway is less clear. Here we show that MutLγ (MLH1-MLH3) is the MutL complex responsible for GAA•TTC repeat expansion. Lentiviral expression of shRNA targeting MutL nuclease components MLH1, PMS2, and MLH3 revealed that reduced expression of MLH1 or MLH3 reduced the repeat expansion rate in a human Friedreich ataxia cell model, while targeting PMS2 did not. Using splice-switching oligonucleotides we show that MLH3 isoform 1 is active in GAA•TTC repeat expansion while the nuclease-deficient MLH3 isoform 2 is not. MLH3 isoform switching slowed repeat expansion in both model cells and FRDA patient fibroblasts. Our work indicates a specific and active role for MutLγ in the expansion process and reveals plausible targets for disease-modifying therapies.
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Affiliation(s)
- Anasheh Halabi
- Division of Neurology, Department of Neurosciences, University of California, San Diego, CA 92103, USA
| | - Kayla T B Fuselier
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
| | - Ed Grabczyk
- Department of Genetics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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37
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Polyzos AA, Wood NI, Williams P, Wipf P, Morton AJ, McMurray CT. XJB-5-131-mediated improvement in physiology and behaviour of the R6/2 mouse model of Huntington's disease is age- and sex- dependent. PLoS One 2018; 13:e0194580. [PMID: 29630611 PMCID: PMC5890981 DOI: 10.1371/journal.pone.0194580] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Accepted: 03/06/2018] [Indexed: 11/18/2022] Open
Abstract
We have reported that the radical scavenger XJB-5-131 attenuates or reverses progression of the disease phenotype in the HdhQ(150/150) mouse, a slow onset model of HD. Here, we tested whether XJB-5-131 has beneficial effects in R6/2 mice, a severe early onset model of HD. We found that XJB-5-131 has beneficial effects in R6/2 mice, by delaying features of the motor and histological phenotype. The impact was sex-dependent, with a stronger effect in male mice. XJB-5-131 treatment improved some locomotor deficits in female R6/2 mice, but the effects were, in general, greater in male mice. Chronic treatment of male R6/2 mice with XJB-5-1-131 reduced weight loss, and improved the motor and temperature regulation deficits, especially in male mice. Treatment with XJB-5-131 had no effect on the lifespan of R6/2 mice. Nevertheless, it significantly slowed somatic expansion at 90 days, and reduced the density of inclusions. Our data show that while treatment with XJB-5-131 had complex effects on the phenotype of R6/2 mice, it produced a number of significant improvements in this severe model of HD.
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Affiliation(s)
- Aris A. Polyzos
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
| | - Nigel I. Wood
- Department of Physiology, Development, and Neuroscience, Anatomy Building, University of Cambridge, Cambridge, United Kingdom
| | - Paul Williams
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, United States of America
| | - A. Jennifer Morton
- Department of Physiology, Development, and Neuroscience, Anatomy Building, University of Cambridge, Cambridge, United Kingdom
| | - Cynthia T. McMurray
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States of America
- * E-mail:
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38
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Holmans PA, Massey TH, Jones L. Genetic modifiers of Mendelian disease: Huntington's disease and the trinucleotide repeat disorders. Hum Mol Genet 2018; 26:R83-R90. [PMID: 28977442 DOI: 10.1093/hmg/ddx261] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 07/03/2017] [Indexed: 02/06/2023] Open
Abstract
In the decades since the genes and mutations associated with the commoner Mendelian disorders were first discovered, technological advances in genetic analysis have made finding genomic variation a much less onerous task. Recently, the global efforts to collect subjects with Mendelian disorders, to better define the disorders and to empower appropriate clinical trials, along with improved genetic technologies, have allowed the identification of genetic variation that does not cause disease, but substantially modifies disease presentation. The advantage of this is it identifies biological pathways and molecules, that, if modified in people, might alter disease presentation. In Huntington's disease (HD), caused by an expanded CAG repeat tract in HTT, genetic variation has been uncovered that is associated with change in the onset or progression of disease. Some of this variation lies in genes that are part of the DNA damage response, previously suggested to be important in modulating expansion of the repeat tract in germline and somatic cells. The genetic evidence implicates a DNA damage response-related pathway in modulating the pathogenicity of the repeat tracts in HD, and possibly, in other trinucleotide repeat disorders. These findings offer new targets for drug development in these currently intractable disorders.
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Affiliation(s)
- Peter A Holmans
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neuroscience, School of Medicine, Cardiff University, Cardiff CF24 4HQ, UK
| | - Thomas H Massey
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neuroscience, School of Medicine, Cardiff University, Cardiff CF24 4HQ, UK
| | - Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, Division of Psychological Medicine and Clinical Neuroscience, School of Medicine, Cardiff University, Cardiff CF24 4HQ, UK
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39
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Leija-Salazar M, Piette C, Proukakis C. Review: Somatic mutations in neurodegeneration. Neuropathol Appl Neurobiol 2018; 44:267-285. [PMID: 29369391 DOI: 10.1111/nan.12465] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 01/13/2018] [Indexed: 12/22/2022]
Abstract
Somatic mutations are postzygotic mutations which may lead to mosaicism, the presence of cells with genetic differences in an organism. Their role in cancer is well established, but detailed investigation in health and other diseases has only been recently possible. This has been empowered by the improvements of sequencing techniques, including single-cell sequencing, which can still be error-prone but is rapidly improving. Mosaicism appears relatively common in the human body, including the normal brain, probably arising in early development, but also potentially during ageing. In this review, we first discuss theoretical considerations and current evidence relevant to somatic mutations in the brain. We present a framework to explain how they may be integrated with current views on neurodegeneration, focusing mainly on sporadic late-onset neurodegenerative diseases (Parkinson's disease, Alzheimer's disease and amyotrophic lateral sclerosis). We review the relevant studies so far, with the first evidence emerging in Alzheimer's in particular. We also discuss the role of mosaicism in inherited neurodegenerative disorders, particularly somatic instability of tandem repeats. We summarize existing views and data to present a model whereby the time of origin and spatial distribution of relevant somatic mutations, combined with any additional risk factors, may partly determine the development and onset age of sporadic neurodegenerative diseases.
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Affiliation(s)
- M Leija-Salazar
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
| | - C Piette
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
| | - C Proukakis
- Department of Clinical Neuroscience, University College London Institute of Neurology, London, UK
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40
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Abstract
Diseases such as Huntington's disease and certain spinocerebellar ataxias are caused by the expansion of genomic cytosine-adenine-guanine (CAG) trinucleotide repeats beyond a specific threshold. These diseases are all characterised by neurological symptoms and central neurodegeneration, but our understanding of how expanded repeats drive neuronal loss is incomplete. Recent human genetic evidence implicates DNA repair pathways, especially mismatch repair, in modifying the onset and progression of CAG repeat diseases. Repair pathways might operate directly on repeat sequences by licensing or inhibiting repeat expansion in neurons. Alternatively, or in addition, because many of the genes containing pathogenic CAG repeats encode proteins that themselves have roles in the DNA damage response, it is possible that repeat expansions impair specific DNA repair pathways. DNA damage could then accrue in neurons, leading to further expansion at repeat loci, thus setting up a vicious cycle of pathology. In this review, we consider DNA damage and repair pathways in postmitotic neurons in the context of disease-causing CAG repeats. Investigating and understanding these pathways, which are clearly relevant in promoting and ameliorating disease in humans, is a research priority, as they are known to modify disease and therefore constitute prevalidated drug targets.
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Affiliation(s)
- Thomas H Massey
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, Cardiff, CF24 4HQ, UK
| | - Lesley Jones
- Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, Hadyn Ellis Building, Cardiff University, Cardiff, CF24 4HQ, UK
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41
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The Chromatin Remodeler Isw1 Prevents CAG Repeat Expansions During Transcription in Saccharomyces cerevisiae. Genetics 2018; 208:963-976. [PMID: 29305386 PMCID: PMC5844344 DOI: 10.1534/genetics.117.300529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/02/2018] [Indexed: 12/23/2022] Open
Abstract
CAG/CTG trinucleotide repeat expansions cause several degenerative neurological and muscular diseases. Koch et al. show that the chromatin remodeling... CAG/CTG trinucleotide repeats are unstable sequences that are difficult to replicate, repair, and transcribe due to their structure-forming nature. CAG repeats strongly position nucleosomes; however, little is known about the chromatin remodeling needed to prevent repeat instability. In a Saccharomyces cerevisiae model system with CAG repeats carried on a YAC, we discovered that the chromatin remodeler Isw1 is required to prevent CAG repeat expansions during transcription. CAG repeat expansions in the absence of Isw1 were dependent on both transcription-coupled repair (TCR) and base-excision repair (BER). Furthermore, isw1∆ mutants are sensitive to methyl methanesulfonate (MMS) and exhibit synergistic MMS sensitivity when combined with BER or TCR pathway mutants. We conclude that CAG expansions in the isw1∆ mutant occur during a transcription-coupled excision repair process that involves both TCR and BER pathways. We observed increased RNA polymerase II (RNAPII) occupancy at the CAG repeat when transcription of the repeat was induced, but RNAPII binding did not change in isw1∆ mutants, ruling out a role for Isw1 remodeling in RNAPII progression. However, nucleosome occupancy over a transcribed CAG tract was altered in isw1∆ mutants. Based on the known role of Isw1 in the reestablishment of nucleosomal spacing after transcription, we suggest that a defect in this function allows DNA structures to form within repetitive DNA tracts, resulting in inappropriate excision repair and repeat-length changes. These results establish a new function for Isw1 in directly maintaining the chromatin structure at the CAG repeat, thereby limiting expansions that can occur during transcription-coupled excision repair.
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42
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Abstract
Huntington's disease (HD) is caused by a CAG repeat expansion in the HTT gene. Repeat length can change over time, both in individual cells and between generations, and longer repeats may drive pathology. Cellular DNA repair systems have long been implicated in CAG repeat instability but recent genetic evidence from humans linking DNA repair variants to HD onset and progression has reignited interest in this area. The DNA damage response plays an essential role in maintaining genome stability, but may also license repeat expansions in the context of HD. In this chapter we summarize the methods developed to assay CAG repeat expansion/contraction in vitro and in cells, and review the DNA repair genes tested in mouse models of HD. While none of these systems is currently ideal, new technologies, such as long-read DNA sequencing, should improve the sensitivity of assays to assess the effects of DNA repair pathways in HD. Improved assays will be essential precursors to high-throughput testing of small molecules that can alter specific steps in DNA repair pathways and perhaps ameliorate expansion or enhance contraction of the HTT CAG repeat.
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43
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Minimizing carry-over PCR contamination in expanded CAG/CTG repeat instability applications. Sci Rep 2017; 7:18026. [PMID: 29269788 PMCID: PMC5740160 DOI: 10.1038/s41598-017-18168-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/06/2017] [Indexed: 11/08/2022] Open
Abstract
Expanded CAG/CTG repeats underlie the aetiology of 14 neurological and neuromuscular disorders. The size of the repeat tract determines in large part the severity of these disorders with longer tracts causing more severe phenotypes. Expanded CAG/CTG repeats are also unstable in somatic tissues, which is thought to modify disease progression. Routine molecular biology applications involving these repeats, including quantifying their instability, are plagued by low PCR yields. This leads to the need for setting up more PCRs of the same locus, thereby increasing the risk of carry-over contamination. Here we aimed to reduce this risk by pre-treating the samples with a Uracil N-Glycosylase (Ung) and using dUTP instead of dTTP in PCRs. We successfully applied this method to the PCR amplification of expanded CAG/CTG repeats, their sequencing, and their molecular cloning. In addition, we optimized the gold-standard method for measuring repeat instability, small-pool PCR (SP-PCR), such that it can be used together with Ung and dUTP-containing PCRs, without compromising data quality. We performed SP-PCR on myotonic-dystrophy-derived samples containing an expansion as large as 1000 repeats, demonstrating the applicability to clinically-relevant material. Thus, we expect the protocols herein to be applicable for molecular diagnostics of expanded repeat disorders.
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Long A, Napierala JS, Polak U, Hauser L, Koeppen AH, Lynch DR, Napierala M. Somatic instability of the expanded GAA repeats in Friedreich's ataxia. PLoS One 2017; 12:e0189990. [PMID: 29261783 PMCID: PMC5736210 DOI: 10.1371/journal.pone.0189990] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Accepted: 12/06/2017] [Indexed: 12/22/2022] Open
Abstract
Friedreich's ataxia (FRDA) is a genetic neurodegenerative disorder caused by transcriptional silencing of the frataxin gene (FXN) due to expansions of GAA repeats in intron 1. FRDA manifests with multiple symptoms, which may include ataxia, cardiomyopathy and diabetes mellitus. Expanded GAA tracts are genetically unstable, exhibiting both expansions and contractions. GAA length correlates with severity of FRDA symptoms and inversely with age of onset. Thus, tissue-specific somatic instability of long GAA repeats may be implicated in the development of symptoms and disease progression. Herein, we determined the extent of somatic instability of the GAA repeats in heart, cerebral cortex, spinal cord, cerebellar cortex, and pancreatic tissues from 15 FRDA patients. Results demonstrate differences in the lengths of the expanded GAAs among different tissues, with significantly longer GAA tracts detected in heart and pancreas than in other tissues. The expansion bias detected in heart and pancreas may contribute to disease onset and progression, making the mechanism of somatic instability an important target for therapy. Additionally, we detected significant differences in GAA tract lengths between lymphocytes and fibroblast pairs derived from 16 FRDA patients, with longer GAA tracts present in the lymphocytes. This result urges caution in direct comparisons of data obtained in these frequently used FRDA models. Furthermore, we conducted a longitudinal analysis of the GAA repeat length in lymphocytes collected over a span of 7-9 years and demonstrated progressive expansions of the GAAs with maximum gain of approximately 9 repeats per year. Continuous GAA expansions throughout the patient's lifespan, as observed in FRDA lymphocytes, should be considered in clinical trial designs and data interpretation.
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Affiliation(s)
- Ashlee Long
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Jill S. Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Urszula Polak
- Department of Molecular Carcinogenesis, Center for Cancer Epigenetics, University of Texas MD Anderson Cancer Center, Smithville, Texas, United States of America
| | - Lauren Hauser
- Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | | | - David R. Lynch
- Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania, United States of America
| | - Marek Napierala
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
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Maiuri T, Mocle AJ, Hung CL, Xia J, van Roon-Mom WMC, Truant R. Huntingtin is a scaffolding protein in the ATM oxidative DNA damage response complex. Hum Mol Genet 2017; 26:395-406. [PMID: 28017939 DOI: 10.1093/hmg/ddw395] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2016] [Accepted: 11/11/2016] [Indexed: 11/15/2022] Open
Abstract
Huntington's disease (HD) is an age-dependent neurodegenerative disease. DNA repair pathways have recently been implicated as the most predominant modifiers of age of onset in HD patients. We report that endogenous huntingtin protein directly participates in oxidative DNA damage repair. Using novel chromobodies to detect endogenous human huntingtin in live cells, we show that localization of huntingtin to DNA damage sites is dependent on the kinase activity of ataxia telangiectasia mutated (ATM) protein. Super-resolution microscopy and biochemical assays revealed that huntingtin co-localizes with and scaffolds proteins of the DNA damage response pathway in response to oxidative stress. In HD patient fibroblasts bearing typical clinical HD allele lengths, we demonstrate that there is deficient oxidative DNA damage repair. We propose that DNA damage in HD is caused by dysfunction of the mutant huntingtin protein in DNA repair, and accumulation of DNA oxidative lesions due to elevated reactive oxygen species may contribute to the onset of HD.
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Affiliation(s)
- Tamara Maiuri
- Department of Biochemistry and Biomedical Research, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Canada L8N3Z5
| | - Andrew J Mocle
- Department of Biochemistry and Biomedical Research, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Canada L8N3Z5
| | - Claudia L Hung
- Department of Biochemistry and Biomedical Research, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Canada L8N3Z5
| | - Jianrun Xia
- Department of Biochemistry and Biomedical Research, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Canada L8N3Z5
| | - Willeke M C van Roon-Mom
- Center for Human and Clinical Genetics, Leiden University Medical Center, Postzone S4-0P, P.O. Box 9600 2300RC Leiden, The Netherlands
| | - Ray Truant
- Department of Biochemistry and Biomedical Research, McMaster University, HSC 4N54, 1200 Main Street West, Hamilton, Canada L8N3Z5
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Polyzos AA, McMurray CT. Close encounters: Moving along bumps, breaks, and bubbles on expanded trinucleotide tracts. DNA Repair (Amst) 2017; 56:144-155. [PMID: 28690053 PMCID: PMC5558859 DOI: 10.1016/j.dnarep.2017.06.017] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Expansion of simple triplet repeats (TNR) underlies more than 30 severe degenerative diseases. There is a good understanding of the major pathways generating an expansion, and the associated polymerases that operate during gap filling synthesis at these "difficult to copy" sequences. However, the mechanism by which a TNR is repaired depends on the type of lesion, the structural features imposed by the lesion, the assembled replication/repair complex, and the polymerase that encounters it. The relationships among these parameters are exceptionally complex and how they direct pathway choice is poorly understood. In this review, we consider the properties of polymerases, and how encounters with GC-rich or abnormal structures might influence polymerase choice and the success of replication and repair. Insights over the last three years have highlighted new mechanisms that provide interesting choices to consider in protecting genome stability.
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Affiliation(s)
- Aris A Polyzos
- MBIB Division, Lawrence Berkeley Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, United States
| | - Cynthia T McMurray
- MBIB Division, Lawrence Berkeley Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, United States.
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A selective inhibitor of histone deacetylase 3 prevents cognitive deficits and suppresses striatal CAG repeat expansions in Huntington's disease mice. Sci Rep 2017; 7:6082. [PMID: 28729730 PMCID: PMC5519595 DOI: 10.1038/s41598-017-05125-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 05/24/2017] [Indexed: 12/03/2022] Open
Abstract
Huntington’s disease (HD) is a neurodegenerative disorder whose major symptoms include progressive motor and cognitive dysfunction. Cognitive decline is a critical quality of life concern for HD patients and families. The enzyme histone deacetylase 3 (HDAC3) appears to be important in HD pathology by negatively regulating genes involved in cognitive functions. Furthermore, HDAC3 has been implicated in the aberrant transcriptional patterns that help cause disease symptoms in HD mice. HDAC3 also helps fuel CAG repeat expansions in human cells, suggesting that HDAC3 may power striatal expansions in the HTT gene thought to drive disease progression. This multifaceted role suggests that early HDAC3 inhibition offers an attractive mechanism to prevent HD cognitive decline and to suppress striatal expansions. This hypothesis was investigated by treating HdhQ111 knock-in mice with the HDAC3-selective inhibitor RGFP966. Chronic early treatment prevented long-term memory impairments and normalized specific memory-related gene expression in hippocampus. Additionally, RGFP966 prevented corticostriatal-dependent motor learning deficits, significantly suppressed striatal CAG repeat expansions, partially rescued striatal protein marker expression and reduced accumulation of mutant huntingtin oligomeric forms. These novel results highlight RGFP966 as an appealing multiple-benefit therapy in HD that concurrently prevents cognitive decline and suppresses striatal CAG repeat expansions.
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Abstract
In this review, we discuss how two evolutionarily conserved pathways at the interface of DNA replication and repair, template switching and break-induced replication, lead to the deleterious large-scale expansion of trinucleotide DNA repeats that cause numerous hereditary diseases. We highlight that these pathways, which originated in prokaryotes, may be subsequently hijacked to maintain long DNA microsatellites in eukaryotes. We suggest that the negative mutagenic outcomes of these pathways, exemplified by repeat expansion diseases, are likely outweighed by their positive role in maintaining functional repetitive regions of the genome such as telomeres and centromeres.
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Affiliation(s)
| | - Jane C Kim
- Department of Biological Sciences, California State University San Marcos, San Marcos, CA, USA
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Talhaoui I, Matkarimov BT, Tchenio T, Zharkov DO, Saparbaev MK. Aberrant base excision repair pathway of oxidatively damaged DNA: Implications for degenerative diseases. Free Radic Biol Med 2017; 107:266-277. [PMID: 27890638 DOI: 10.1016/j.freeradbiomed.2016.11.040] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2016] [Revised: 11/22/2016] [Accepted: 11/23/2016] [Indexed: 02/06/2023]
Abstract
In cellular organisms composition of DNA is constrained to only four nucleobases A, G, T and C, except for minor DNA base modifications such as methylation which serves for defence against foreign DNA or gene expression regulation. Interestingly, this severe evolutionary constraint among other things demands DNA repair systems to discriminate between regular and modified bases. DNA glycosylases specifically recognize and excise damaged bases among vast majority of regular bases in the base excision repair (BER) pathway. However, the mismatched base pairs in DNA can occur from a spontaneous conversion of 5-methylcytosine to thymine and DNA polymerase errors during replication. To counteract these mutagenic threats to genome stability, cells evolved special DNA repair systems that target the non-damaged DNA strand in a duplex to remove mismatched regular DNA bases. Mismatch-specific adenine- and thymine-DNA glycosylases (MutY/MUTYH and TDG/MBD4, respectively) initiated BER and mismatch repair (MMR) pathways can recognize and remove normal DNA bases in mismatched DNA duplexes. Importantly, in DNA repair deficient cells bacterial MutY, human TDG and mammalian MMR can act in the aberrant manner: MutY and TDG removes adenine and thymine opposite misincorporated 8-oxoguanine and damaged adenine, respectively, whereas MMR removes thymine opposite to O6-methylguanine. These unusual activities lead either to mutations or futile DNA repair, thus indicating that the DNA repair pathways which target non-damaged DNA strand can act in aberrant manner and introduce genome instability in the presence of unrepaired DNA lesions. Evidences accumulated showing that in addition to the accumulation of oxidatively damaged DNA in cells, the aberrant DNA repair can also contribute to cancer, brain disorders and premature senescence. For example, the aberrant BER and MMR pathways for oxidized guanine residues can lead to trinucleotide expansion that underlies Huntington's disease, a severe hereditary neurodegenerative syndrome. This review summarises the present knowledge about the aberrant DNA repair pathways for oxidized base modifications and their possible role in age-related diseases.
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Affiliation(s)
- Ibtissam Talhaoui
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale Contre le Cancer, CNRS UMR8200, Université Paris-Sud, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France
| | - Bakhyt T Matkarimov
- National laboratory Astana, Nazarbayev University, Astana 010000, Kazakhstan
| | - Thierry Tchenio
- LBPA, UMR8113 ENSC - CNRS, Ecole Normale Supérieure de Cachan, Cachan, France
| | - Dmitry O Zharkov
- SB RAS Institute of Chemical Biology and Fundamental Medicine, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia
| | - Murat K Saparbaev
- Groupe «Réparation de l'ADN», Equipe Labellisée par la Ligue Nationale Contre le Cancer, CNRS UMR8200, Université Paris-Sud, Gustave Roussy Cancer Campus, F-94805 Villejuif Cedex, France.
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Boiteux S, Coste F, Castaing B. Repair of 8-oxo-7,8-dihydroguanine in prokaryotic and eukaryotic cells: Properties and biological roles of the Fpg and OGG1 DNA N-glycosylases. Free Radic Biol Med 2017; 107:179-201. [PMID: 27903453 DOI: 10.1016/j.freeradbiomed.2016.11.042] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Revised: 11/22/2016] [Accepted: 11/25/2016] [Indexed: 01/23/2023]
Abstract
Oxidatively damaged DNA results from the attack of sugar and base moieties by reactive oxygen species (ROS), which are formed as byproducts of normal cell metabolism and during exposure to endogenous or exogenous chemical or physical agents. Guanine, having the lowest redox potential, is the DNA base the most susceptible to oxidation, yielding products such as 8-oxo-7,8-dihydroguanine (8-oxoG) and 2-6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG). In DNA, 8-oxoG was shown to be mutagenic yielding GC to TA transversions upon incorporation of dAMP opposite this lesion by replicative DNA polymerases. In prokaryotic and eukaryotic cells, 8-oxoG is primarily repaired by the base excision repair pathway (BER) initiated by a DNA N-glycosylase, Fpg and OGG1, respectively. In Escherichia coli, Fpg cooperates with MutY and MutT to prevent 8-oxoG-induced mutations, the "GO-repair system". In Saccharomyces cerevisiae, OGG1 cooperates with nucleotide excision repair (NER), mismatch repair (MMR), post-replication repair (PRR) and DNA polymerase η to prevent mutagenesis. Human and mouse cells mobilize all these pathways using OGG1, MUTYH (MutY-homolog also known as MYH), MTH1 (MutT-homolog also known as NUDT1), NER, MMR, NEILs and DNA polymerases η and λ, to prevent 8-oxoG-induced mutations. In fact, mice deficient in both OGG1 and MUTYH develop cancer in different organs at adult age, which points to the critical impact of 8-oxoG repair on genetic stability in mammals. In this review, we will focus on Fpg and OGG1 proteins, their biochemical and structural properties as well as their biological roles. Other DNA N-glycosylases able to release 8-oxoG from damaged DNA in various organisms will be discussed. Finally, we will report on the role of OGG1 in human disease and the possible use of 8-oxoG DNA N-glycosylases as therapeutic targets.
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Affiliation(s)
- Serge Boiteux
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France.
| | - Franck Coste
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France
| | - Bertrand Castaing
- Centre de Biophysique Moléculaire, CNRS, UPR4301, rue Charles Sadron, 45072 Orléans, France.
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