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Huntington Disease as a Neurodevelopmental Disorder and Early Signs of the Disease in Stem Cells. Mol Neurobiol 2017; 55:3351-3371. [PMID: 28497201 PMCID: PMC5842500 DOI: 10.1007/s12035-017-0477-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Accepted: 03/01/2017] [Indexed: 02/07/2023]
Abstract
Huntington disease (HD) is a dominantly inherited disorder caused by a CAG expansion mutation in the huntingtin (HTT) gene, which results in the HTT protein that contains an expanded polyglutamine tract. The adult form of HD exhibits a late onset of the fully symptomatic phase. However, there is also a long presymptomatic phase, which has been increasingly investigated and recognized as important for the disease development. Moreover, the juvenile form of HD, evoked by a higher number of CAG repeats, resembles a neurodevelopmental disorder and has recently been the focus of additional interest. Multiple lines of data, such as the developmental necessity of HTT, its role in the cell cycle and neurogenesis, and findings from pluripotent stem cells, suggest the existence of a neurodevelopmental component in HD pathogenesis. Therefore, we discuss the early molecular pathogenesis of HD in pluripotent and neural stem cells, with respect to the neurodevelopmental aspects of HD.
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Velázquez-Pérez L, Rodríguez-Labrada R, Laffita-Mesa JM. Prodromal spinocerebellar ataxia type 2: Prospects for early interventions and ethical challenges. Mov Disord 2017; 32:708-718. [DOI: 10.1002/mds.26969] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 01/24/2017] [Accepted: 01/30/2017] [Indexed: 12/29/2022] Open
Affiliation(s)
| | | | - José Miguel Laffita-Mesa
- Centre for the Research and Rehabilitation of Hereditary Ataxias; Holguín Cuba
- Department of Clinical Neuroscience; Karolinska Universitetssjukhuset; Stockholm Sweden
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Jones L, Houlden H, Tabrizi SJ. DNA repair in the trinucleotide repeat disorders. Lancet Neurol 2017; 16:88-96. [PMID: 27979358 DOI: 10.1016/s1474-4422(16)30350-7] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Revised: 09/22/2016] [Accepted: 10/27/2016] [Indexed: 02/07/2023]
Abstract
BACKGROUND Inherited diseases caused by unstable repeated DNA sequences are rare, but together represent a substantial cause of morbidity. Trinucleotide repeat disorders are severe, usually life-shortening, neurological disorders caused by nucleotide expansions, and most have no disease-modifying treatments. Longer repeat expansions are associated with genetic anticipation (ie, earlier disease onset in successive generations), although the differences in age at onset are not entirely accounted for by repeat length. Such phenotypic variation within disorders implies the existence of additional modifying factors in pathways that can potentially be modulated to treat disease. RECENT DEVELOPMENTS A genome-wide association study detected genetic modifiers of age at onset in Huntington's disease. Similar findings were seen in the spinocerebellar ataxias, indicating an association between DNA damage-response and repair pathways and the age at onset of disease. These studies also suggest that a common genetic mechanism modulates age at onset across polyglutamine diseases and could extend to other repeat expansion disorders. Genetic defects in DNA repair underlie other neurodegenerative disorders (eg, ataxia-telangiectasia), and DNA double-strand breaks are crucial to the modulation of early gene expression, which provides a mechanistic link between DNA repair and neurodegeneration. Mismatch and base-excision repair are important in the somatic expansion of repeated sequences in mouse models of trinucleotide repeat disorders, and somatic expansion of the expanded CAG tract in HTT correlates with age at onset of Huntington's disease and other trinucleotide repeat disorders. WHERE NEXT?: To understand the common genetic architecture of trinucleotide repeat disorders and any further genetic susceptibilities in individual disorders, genetic analysis with increased numbers of variants and sample sizes is needed, followed by sequencing approaches to define the phenotype-modifying variants. The findings must then be translated into cell biology analyses to elucidate the mechanisms through which the genetic variants operate. Genes that have roles in the DNA damage response could underpin a common DNA repeat-based mechanism and provide new therapeutic targets (and hence therapeutics) in multiple trinucleotide repeat disorders.
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Affiliation(s)
- Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, UK.
| | - Henry Houlden
- Department of Molecular Neuroscience and MRC Centre for Neuromuscular Diseases, Institute of Neurology, Queen Square, London, UK
| | - Sarah J Tabrizi
- UCL Huntington's Disease Centre, Department of Neurodegenerative Disease, Institute of Neurology, University College London, London, UK
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Polyzos AA, McMurray CT. The chicken or the egg: mitochondrial dysfunction as a cause or consequence of toxicity in Huntington's disease. Mech Ageing Dev 2017; 161:181-197. [PMID: 27634555 PMCID: PMC5543717 DOI: 10.1016/j.mad.2016.09.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 09/07/2016] [Accepted: 09/12/2016] [Indexed: 01/30/2023]
Abstract
Mitochondrial dysfunction and ensuing oxidative damage is typically thought to be a primary cause of Huntington's disease, Alzheimer's disease, and Parkinson disease. There is little doubt that mitochondria (MT) become defective as neurons die, yet whether MT defects are the primary cause or a detrimental consequence of toxicity remains unanswered. Oxygen consumption rate (OCR) and glycolysis provide sensitive and informative measures of the functional status MT and the cells metabolic regulation, yet these measures differ depending on the sample source; species, tissue type, age at measurement, and whether MT are measured in purified form or in a cell. The effects of these various parameters are difficult to quantify and not fully understood, but clearly have an impact on interpreting the bioenergetics of MT or their failure in disease states. A major goal of the review is to discuss issues and coalesce detailed information into a reference table to help in assessing mitochondrial dysfunction as a cause or consequence of Huntington's disease.
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Affiliation(s)
- Aris A Polyzos
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA.
| | - Cynthia T McMurray
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA.
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Contracting CAG/CTG repeats using the CRISPR-Cas9 nickase. Nat Commun 2016; 7:13272. [PMID: 27827362 PMCID: PMC5105158 DOI: 10.1038/ncomms13272] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/12/2016] [Indexed: 12/15/2022] Open
Abstract
CAG/CTG repeat expansions cause over 13 neurological diseases that remain without a cure. Because longer tracts cause more severe phenotypes, contracting them may provide a therapeutic avenue. No currently known agent can specifically generate contractions. Using a GFP-based chromosomal reporter that monitors expansions and contractions in the same cell population, here we find that inducing double-strand breaks within the repeat tract causes instability in both directions. In contrast, the CRISPR-Cas9 D10A nickase induces mainly contractions independently of single-strand break repair. Nickase-induced contractions depend on the DNA damage response kinase ATM, whereas ATR inhibition increases both expansions and contractions in a MSH2- and XPA-dependent manner. We propose that DNA gaps lead to contractions and that the type of DNA damage present within the repeat tract dictates the levels and the direction of CAG repeat instability. Our study paves the way towards deliberate induction of CAG/CTG repeat contractions in vivo. The expansion of trinucleotide repeats has been linked to several neurodegenerative disorders. Here, the authors show that the CRISPR-Cas9 nuclease induces both expansions and contractions of the repeat region, whereas the nickase leads predominantly to contractions.
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Abstract
Redox homeostasis is crucial for proper cellular functions, including receptor tyrosine kinase signaling, protein folding, and xenobiotic detoxification. Under basal conditions, there is a balance between oxidants and antioxidants. This balance facilitates the ability of oxidants, such as reactive oxygen species, to play critical regulatory functions through a direct modification of a small number of amino acids (e.g. cysteine) on signaling proteins. These signaling functions leverage tight spatial, amplitude, and temporal control of oxidant concentrations. However, when oxidants overwhelm the antioxidant capacity, they lead to a harmful condition of oxidative stress. Oxidative stress has long been held to be one of the key players in disease progression for Huntington's disease (HD). In this review, we will critically review this evidence, drawing some intermediate conclusions, and ultimately provide a framework for thinking about the role of oxidative stress in the pathophysiology of HD.
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Affiliation(s)
- Amit Kumar
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
| | - Rajiv R. Ratan
- Burke Medical Research Institute, White Plains, NY, USA
- Brain and Mind Research Institute, Weill Medical College of Cornell University, New York, NY, USA
- Department of Neurology, Weill Medical College of Cornell University, New York, NY, USA
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Ups and Downs: Mechanisms of Repeat Instability in the Fragile X-Related Disorders. Genes (Basel) 2016; 7:genes7090070. [PMID: 27657135 PMCID: PMC5042400 DOI: 10.3390/genes7090070] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Revised: 08/30/2016] [Accepted: 09/13/2016] [Indexed: 02/06/2023] Open
Abstract
The Fragile X-related disorders (FXDs) are a group of clinical conditions resulting from the expansion of a CGG/CCG-repeat tract in exon 1 of the Fragile X mental retardation 1 (FMR1) gene. While expansions of the repeat tract predominate, contractions are also seen with the net result being that individuals can show extensive repeat length heterogeneity in different tissues. The mechanisms responsible for expansion and contraction are still not well understood. This review will discuss what is known about these processes and current evidence that supports a model in which expansion arises from the interaction of components of the base excision repair, mismatch repair and transcription coupled repair pathways.
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Lai Y, Budworth H, Beaver JM, Chan NLS, Zhang Z, McMurray CT, Liu Y. Crosstalk between MSH2-MSH3 and polβ promotes trinucleotide repeat expansion during base excision repair. Nat Commun 2016; 7:12465. [PMID: 27546332 PMCID: PMC4996945 DOI: 10.1038/ncomms12465] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 07/06/2016] [Indexed: 01/07/2023] Open
Abstract
Studies in knockout mice provide evidence that MSH2-MSH3 and the BER machinery promote trinucleotide repeat (TNR) expansion, yet how these two different repair pathways cause the mutation is unknown. Here we report the first molecular crosstalk mechanism, in which MSH2-MSH3 is used as a component of the BER machinery to cause expansion. On its own, pol β fails to copy TNRs during DNA synthesis, and bypasses them on the template strand to cause deletion. Remarkably, MSH2-MSH3 not only stimulates pol β to copy through the repeats but also enhances formation of the flap precursor for expansion. Our results provide direct evidence that MMR and BER, operating together, form a novel hybrid pathway that changes the outcome of TNR instability from deletion to expansion during the removal of oxidized bases. We propose that cells implement crosstalk strategies and share machinery when a canonical pathway is ineffective in removing a difficult lesion.
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Affiliation(s)
- Yanhao Lai
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
| | - Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Jill M. Beaver
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
| | - Nelson L. S. Chan
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Zunzhen Zhang
- Department of Occupational and Environmental Health, Sichuan University West China School of Public Health, 16#, Section 3, Renmin Nan Lu, Chengdu, Sichuan 610041, China
| | - Cynthia T. McMurray
- Life Sciences Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, 33R249, Berkeley, California 94720, USA
| | - Yuan Liu
- Department of Chemistry and Biochemistry, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
- Biochemistry Ph.D. Program, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
- Biomolecular Sciences Institute, School of Integrated Sciences and Humanity, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
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Bettencourt C, Hensman‐Moss D, Flower M, Wiethoff S, Brice A, Goizet C, Stevanin G, Koutsis G, Karadima G, Panas M, Yescas‐Gómez P, García‐Velázquez LE, Alonso‐Vilatela ME, Lima M, Raposo M, Traynor B, Sweeney M, Wood N, Giunti P, Durr A, Holmans P, Houlden H, Tabrizi SJ, Jones L. DNA repair pathways underlie a common genetic mechanism modulating onset in polyglutamine diseases. Ann Neurol 2016; 79:983-90. [PMID: 27044000 PMCID: PMC4914895 DOI: 10.1002/ana.24656] [Citation(s) in RCA: 146] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Revised: 03/30/2016] [Accepted: 03/30/2016] [Indexed: 12/14/2022]
Abstract
OBJECTIVE The polyglutamine diseases, including Huntington's disease (HD) and multiple spinocerebellar ataxias (SCAs), are among the commonest hereditary neurodegenerative diseases. They are caused by expanded CAG tracts, encoding glutamine, in different genes. Longer CAG repeat tracts are associated with earlier ages at onset, but this does not account for all of the difference, and the existence of additional genetic modifying factors has been suggested in these diseases. A recent genome-wide association study (GWAS) in HD found association between age at onset and genetic variants in DNA repair pathways, and we therefore tested whether the modifying effects of variants in DNA repair genes have wider effects in the polyglutamine diseases. METHODS We assembled an independent cohort of 1,462 subjects with HD and polyglutamine SCAs, and genotyped single-nucleotide polymorphisms (SNPs) selected from the most significant hits in the HD study. RESULTS In the analysis of DNA repair genes as a group, we found the most significant association with age at onset when grouping all polyglutamine diseases (HD+SCAs; p = 1.43 × 10(-5) ). In individual SNP analysis, we found significant associations for rs3512 in FAN1 with HD+SCAs (p = 1.52 × 10(-5) ) and all SCAs (p = 2.22 × 10(-4) ) and rs1805323 in PMS2 with HD+SCAs (p = 3.14 × 10(-5) ), all in the same direction as in the HD GWAS. INTERPRETATION We show that DNA repair genes significantly modify age at onset in HD and SCAs, suggesting a common pathogenic mechanism, which could operate through the observed somatic expansion of repeats that can be modulated by genetic manipulation of DNA repair in disease models. This offers novel therapeutic opportunities in multiple diseases. Ann Neurol 2016;79:983-990.
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Affiliation(s)
- Conceição Bettencourt
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
- Department of Clinical and Experimental Epilepsy, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | - Davina Hensman‐Moss
- Department of Neurodegenerative Disease, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | - Michael Flower
- Department of Neurodegenerative Disease, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | - Sarah Wiethoff
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
- Center for Neurology and Hertie Institute for Clinical Brain ResearchEberhard‐Karls‐UniversityTübingenGermany
| | - Alexis Brice
- Inserm U 1127, CNRS UMR 7225, Sorbonne UniversitésUPMC University Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM)ParisFrance
- APHP, Department of GeneticsUniversity Hospital Pitié‐Salpêtrière75013 ParisFrance
| | - Cyril Goizet
- Université Bordeaux, Laboratoire Maladies Rares: Génétique et MétabolismeINSERM1211BordeauxFrance
- CHU Pellegrin, Service de Génétique Médicale, F‐33000BordeauxFrance
| | - Giovanni Stevanin
- Inserm U 1127, CNRS UMR 7225, Sorbonne UniversitésUPMC University Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM)ParisFrance
- Ecole Pratique des Hautes Etudes75014 ParisFrance
| | - Georgios Koutsis
- Neurogenetics Unit, 1st Department of NeurologyUniversity of Athens Medical School, Eginition Hospital115 28 AthensGreece
| | - Georgia Karadima
- Neurogenetics Unit, 1st Department of NeurologyUniversity of Athens Medical School, Eginition Hospital115 28 AthensGreece
| | - Marios Panas
- Neurogenetics Unit, 1st Department of NeurologyUniversity of Athens Medical School, Eginition Hospital115 28 AthensGreece
| | - Petra Yescas‐Gómez
- Neurogenetics Department, National Institute of Neurology and Neurosurgery“Manuel Velasco Suárez”Mexico City CP14269Mexico
| | | | - María Elisa Alonso‐Vilatela
- Neurogenetics Department, National Institute of Neurology and Neurosurgery“Manuel Velasco Suárez”Mexico City CP14269Mexico
| | - Manuela Lima
- Department of BiologyUniversity of the Azores9500‐321 Ponta DelgadaPortugal
- Instituto de Investigação e Inovação em SaúdeUniversidade do Porto4150‐180 PortoPortugal
- Institute for Molecular and Cell Biology (IBMC)University of Porto4150‐180 PortoPortugal
| | - Mafalda Raposo
- Department of BiologyUniversity of the Azores9500‐321 Ponta DelgadaPortugal
- Instituto de Investigação e Inovação em SaúdeUniversidade do Porto4150‐180 PortoPortugal
- Institute for Molecular and Cell Biology (IBMC)University of Porto4150‐180 PortoPortugal
| | - Bryan Traynor
- Laboratory of Neurogenetics, National Institute of AgingNIHBethesdaMD 20892, USA
| | - Mary Sweeney
- Neurogenetics Unit, National Hospital for Neurology and NeurosurgeryUniversity College London HospitalsLondon WC1N 3BGUnited Kingdom
| | - Nicholas Wood
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | - Paola Giunti
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
- Ataxia Center, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | | | - Alexandra Durr
- Inserm U 1127, CNRS UMR 7225, Sorbonne UniversitésUPMC University Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle épinière (ICM)ParisFrance
- APHP, Department of GeneticsUniversity Hospital Pitié‐Salpêtrière75013 ParisFrance
| | - Peter Holmans
- MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical NeurosciencesCardiff UniversityCardiffCF24 4HQUnited Kingdom
| | - Henry Houlden
- Department of Molecular Neuroscience, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
- Neurogenetics Unit, National Hospital for Neurology and NeurosurgeryUniversity College London HospitalsLondon WC1N 3BGUnited Kingdom
| | - Sarah J. Tabrizi
- Department of Neurodegenerative Disease, Institute of NeurologyUniversity College LondonLondon WC1N 3BGUnited Kingdom
| | - Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical NeurosciencesCardiff UniversityCardiffCF24 4HQUnited Kingdom
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Cilli P, Ventura I, Minoprio A, Meccia E, Martire A, Wilson SH, Bignami M, Mazzei F. Oxidized dNTPs and the OGG1 and MUTYH DNA glycosylases combine to induce CAG/CTG repeat instability. Nucleic Acids Res 2016; 44:5190-203. [PMID: 26980281 PMCID: PMC4914090 DOI: 10.1093/nar/gkw170] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 03/03/2016] [Indexed: 12/13/2022] Open
Abstract
DNA trinucleotide repeat (TNR) expansion underlies several neurodegenerative disorders including Huntington's disease (HD). Accumulation of oxidized DNA bases and their inefficient processing by base excision repair (BER) are among the factors suggested to contribute to TNR expansion. In this study, we have examined whether oxidation of the purine dNTPs in the dNTP pool provides a source of DNA damage that promotes TNR expansion. We demonstrate that during BER of 8-oxoguanine (8-oxodG) in TNR sequences, DNA polymerase β (POL β) can incorporate 8-oxodGMP with the formation of 8-oxodG:C and 8-oxodG:A mispairs. Their processing by the OGG1 and MUTYH DNA glycosylases generates closely spaced incisions on opposite DNA strands that are permissive for TNR expansion. Evidence in HD model R6/2 mice indicates that these DNA glycosylases are present in brain areas affected by neurodegeneration. Consistent with prevailing oxidative stress, the same brain areas contained increased DNA 8-oxodG levels and expression of the p53-inducible ribonucleotide reductase. Our in vitro and in vivo data support a model where an oxidized dNTPs pool together with aberrant BER processing contribute to TNR expansion in non-replicating cells.
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Affiliation(s)
- Piera Cilli
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy Department of Science, University Roma Tre, 00154 Roma, Italy
| | - Ilenia Ventura
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy
| | - Anna Minoprio
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy
| | - Ettore Meccia
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy
| | - Alberto Martire
- Department of Drug Safety and Evaluation, Istituto Superiore di Sanità, 00161 Roma, Italy
| | - Samuel H Wilson
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC 27709, USA
| | - Margherita Bignami
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy
| | - Filomena Mazzei
- Department of Environment and Primary Prevention, Istituto Superiore di Sanità, 00161 Roma, Italy
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Polyzos A, Holt A, Brown C, Cosme C, Wipf P, Gomez-Marin A, Castro MR, Ayala-Peña S, McMurray CT. Mitochondrial targeting of XJB-5-131 attenuates or improves pathophysiology in HdhQ150 animals with well-developed disease phenotypes. Hum Mol Genet 2016; 25:1792-802. [PMID: 26908614 DOI: 10.1093/hmg/ddw051] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/15/2016] [Indexed: 12/14/2022] Open
Abstract
Oxidative damage to mitochondria (MT) is a major mechanism for aging and neurodegeneration. We have developed a novel synthetic antioxidant, XJB-5-131, which directly targets MT, the primary site and primary target of oxidative damage. XJB-5-131 prevents the onset of motor decline in an HdhQ(150/150) mouse model for Huntington's disease (HD) if treatment starts early. Here, we report that XJB-5-131 attenuates or reverses disease progression if treatment occurs after disease onset. In animals with well-developed pathology, XJB-5-131 promotes weight gain, prevents neuronal death, reduces oxidative damage in neurons, suppresses the decline of motor performance or improves it, and reduces a graying phenotype in treated HdhQ(150/150) animals relative to matched littermate controls. XJB-5-131 holds promise as a clinical candidate for the treatment of HD.
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Affiliation(s)
- Aris Polyzos
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA
| | - Amy Holt
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA
| | - Christopher Brown
- Molecular Cellular Biology Program, University of California Berkeley, Berkeley, CA 94720, USA
| | - Celica Cosme
- Molecular Cellular Biology Program, University of California Berkeley, Berkeley, CA 94720, USA
| | - Peter Wipf
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA 15260, USA
| | - Alex Gomez-Marin
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas and Universidad Miguel Hernández, Sant Joan d'Alacant, Spain and
| | - Maríadel R Castro
- Department of Pharmacology and Toxicology, University of Puerto Rico, PO Box 365067, San Juan, PR 00936, USA
| | - Sylvette Ayala-Peña
- Department of Pharmacology and Toxicology, University of Puerto Rico, PO Box 365067, San Juan, PR 00936, USA
| | - Cynthia T McMurray
- Molecular Biophysics and Integrated Bioimaging Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, USA,
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Budworth H, McMurray CT. Problems and solutions for the analysis of somatic CAG repeat expansion and their relationship to Huntington's disease toxicity. Rare Dis 2016; 4:e1131885. [PMID: 27141411 PMCID: PMC4838321 DOI: 10.1080/21675511.2015.1131885] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Revised: 11/17/2015] [Accepted: 12/09/2015] [Indexed: 11/15/2022] Open
Abstract
Huntington's Disease is caused by inheritance of a single disease-length allele harboring an expanded CAG repeat, which continues to expand in somatic tissues with age. Whether somatic expansion contributed to toxicity was unknown. From extensive work from multiple laboratories, it has been made clear that toxicity depended on length of the inherited allele, but whether preventing or delaying somatic repeat expansion in vivo would be beneficial was unknown, since the inherited disease allele was still expressed. In Budworth et al., we provided definitive evidence that suppressing the somatic expansion in mice substantially delays disease onset in littermates that inherit the same disease-length allele. This key discovery opens the door for therapeutic approaches targeted at stopping or shortening the CAG tract during life. The analysis was difficult and, at times, non-standard. Here, we take the opportunity to discuss the challenges, the analytical solutions, and to address some controversial issues with respect to expansion biology.
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Affiliation(s)
- Helen Budworth
- Life Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA, USA
| | - Cynthia T McMurray
- Life Sciences Division, Lawrence Berkeley National Laboratory , Berkeley, CA, USA
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