1
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Caron NS, Anderson C, Black HF, Sanders SS, Lemarié FL, Doty CN, Hayden MR. Reliable Resolution of Full-Length Huntingtin Alleles by Quantitative Immunoblotting. J Huntingtons Dis 2021; 10:355-365. [PMID: 34092649 DOI: 10.3233/jhd-200463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Therapeutics that lower mutant huntingtin (mHTT) have shown promise in preclinical studies and are in clinical development for the treatment of Huntington's disease (HD). Multiple assays have been developed that either quantify mHTT or total HTT but may not accurately measure levels of wild type HTT (wtHTT) in biological samples. OBJECTIVE To optimize a method that can be used to resolve, quantify and directly compare levels of full length wtHTT and mHTT in HD samples. METHODS We provide a detailed quantitative immunoblotting protocol to reproducibly resolve full length wtHTT and mHTT in multiple HD mouse and patient samples. RESULTS We show that this assay can be modified, depending on the sample, to resolve wtHTT and mHTT with a wide range of polyglutamine differences (ΔQs 22-179). We also demonstrate that this method can be used to quantify allele-selective lowering of mHTT using an antisense oligonucleotide in HD patient-derived cells. CONCLUSION This quantitative immunoblotting method can be used to reliably resolve full length HTT alleles with ΔQs≥22 and allows for direct comparison of wtHTT and mHTT levels in HD samples.
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Affiliation(s)
- Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | | | - Hailey Findlay Black
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Shaun S Sanders
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada.,Current address: Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, Canada
| | - Fanny L Lemarié
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Vancouver, BC, Canada
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, BC Children's Hospital Research Institute; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
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2
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Southwell AL, Kordasiewicz HB, Langbehn D, Skotte NH, Parsons MP, Villanueva EB, Caron NS, Østergaard ME, Anderson LM, Xie Y, Cengio LD, Findlay-Black H, Doty CN, Fitsimmons B, Swayze EE, Seth PP, Raymond LA, Frank Bennett C, Hayden MR. Huntingtin suppression restores cognitive function in a mouse model of Huntington's disease. Sci Transl Med 2019; 10:10/461/eaar3959. [PMID: 30282695 DOI: 10.1126/scitranslmed.aar3959] [Citation(s) in RCA: 79] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 05/26/2018] [Accepted: 09/12/2018] [Indexed: 12/12/2022]
Abstract
Huntington's disease (HD) is an autosomal dominant neurodegenerative disorder caused by a mutation in the huntingtin (HTT) protein, resulting in acquisition of toxic functions. Previous studies have shown that lowering mutant HTT has the potential to be broadly beneficial. We previously identified HTT single-nucleotide polymorphisms (SNPs) tightly linked to the HD mutation and developed antisense oligonucleotides (ASOs) targeting HD-SNPs that selectively suppress mutant HTT. We tested allele-specific ASOs in a mouse model of HD. Both early and late treatment reduced cognitive and behavioral impairments in mice. To determine the translational potential of the treatment, we examined the effect of ASO administration on HTT brain expression in nonhuman primates. The treatment induced robust HTT suppression throughout the cortex and limbic system, areas implicated in cognition and psychiatric function. The results suggest that ASOs specifically targeting mutated HTT might have therapeutic effects on HD-mediated cognitive impairments.
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Affiliation(s)
- Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | | | - Douglas Langbehn
- Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA
| | - Niels H Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Matthew P Parsons
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Erika B Villanueva
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | | | - Lisa M Anderson
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Yuanyun Xie
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Louisa Dal Cengio
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Hailey Findlay-Black
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
| | | | | | | | - Lynn A Raymond
- Department of Psychiatry, Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | | | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada.
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3
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Southwell AL, Skotte NH, Villanueva EB, Østergaard ME, Gu X, Kordasiewicz HB, Kay C, Cheung D, Xie Y, Waltl S, Dal Cengio L, Findlay-Black H, Doty CN, Petoukhov E, Iworima D, Slama R, Ooi J, Pouladi MA, Yang XW, Swayze EE, Seth PP, Hayden MR. A novel humanized mouse model of Huntington disease for preclinical development of therapeutics targeting mutant huntingtin alleles. Hum Mol Genet 2017; 26:1115-1132. [PMID: 28104789 DOI: 10.1093/hmg/ddx021] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 01/10/2017] [Indexed: 11/14/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disease caused by a mutation in the huntingtin (HTT) gene. HTT is a large protein, interacts with many partners and is involved in many cellular pathways, which are perturbed in HD. Therapies targeting HTT directly are likely to provide the most global benefit. Thus there is a need for preclinical models of HD recapitulating human HTT genetics. We previously generated a humanized mouse model of HD, Hu97/18, by intercrossing BACHD and YAC18 mice with knockout of the endogenous mouse HD homolog (Hdh). Hu97/18 mice recapitulate the genetics of HD, having two full-length, genomic human HTT transgenes heterozygous for the HD mutation and polymorphisms associated with HD in populations of Caucasian descent. We have now generated a companion model, Hu128/21, by intercrossing YAC128 and BAC21 mice on the Hdh-/- background. Hu128/21 mice have two full-length, genomic human HTT transgenes heterozygous for the HD mutation and polymorphisms associated with HD in populations of East Asian descent and in a minority of patients from other ethnic groups. Hu128/21 mice display a wide variety of HD-like phenotypes that are similar to YAC128 mice. Additionally, both transgenes in Hu128/21 mice match the human HTT exon 1 reference sequence. Conversely, the BACHD transgene carries a floxed, synthetic exon 1 sequence. Hu128/21 mice will be useful for investigations of human HTT that cannot be addressed in Hu97/18 mice, for developing therapies targeted to exon 1, and for preclinical screening of personalized HTT lowering therapies in HD patients of East Asian descent.
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Affiliation(s)
- Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Niels H Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Erika B Villanueva
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | | | - Xiaofeng Gu
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | | | - Chris Kay
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Daphne Cheung
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Yuanyun Xie
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Sabine Waltl
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Louisa Dal Cengio
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Hailey Findlay-Black
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Eugenia Petoukhov
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Diepiriye Iworima
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Ramy Slama
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
| | - Jolene Ooi
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research and the Department of Medicine, National University of Singapore, Singapore 138648
| | - Mahmoud A Pouladi
- Translational Laboratory in Genetic Medicine, Agency for Science, Technology and Research and the Department of Medicine, National University of Singapore, Singapore 138648.,Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - X William Yang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior; Department of Psychiatry and Biobehavioral Sciences, University of California, Los Angeles, CA, USA
| | | | | | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada
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4
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Kay C, Collins JA, Skotte NH, Southwell AL, Warby SC, Caron NS, Doty CN, Nguyen B, Griguoli A, Ross CJ, Squitieri F, Hayden MR. Huntingtin Haplotypes Provide Prioritized Target Panels for Allele-specific Silencing in Huntington Disease Patients of European Ancestry. Mol Ther 2015. [PMID: 26201449 DOI: 10.1038/mt.2015.128] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Huntington disease (HD) is a dominant neurodegenerative disorder caused by a CAG repeat expansion in the Huntingtin gene (HTT). Heterozygous polymorphisms in cis with the mutation allow for allele-specific suppression of the pathogenic HTT transcript as a therapeutic strategy. To prioritize target selection, precise heterozygosity estimates are needed across diverse HD patient populations. Here we present the first comprehensive investigation of all common target alleles across the HTT gene, using 738 reference haplotypes from the 1000 Genomes Project and 2364 haplotypes from HD patients and relatives in Canada, Sweden, France, and Italy. The most common HD haplotypes (A1, A2, and A3a) define mutually exclusive sets of polymorphisms for allele-specific therapy in the greatest number of patients. Across all four populations, a maximum of 80% are treatable using these three target haplotypes. We identify a novel deletion found exclusively on the A1 haplotype, enabling potent and selective silencing of mutant HTT in approximately 40% of the patients. Antisense oligonucleotides complementary to the deletion reduce mutant A1 HTT mRNA by 78% in patient cells while sparing wild-type HTT expression. By suppressing specific haplotypes on which expanded CAG occurs, we demonstrate a rational approach to the development of allele-specific therapy for a monogenic disorder.
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Affiliation(s)
- Chris Kay
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jennifer A Collins
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Niels H Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Simon C Warby
- Department of Psychiatry, Université de Montréal, Montréal, Québec, Canada
| | - Nicholas S Caron
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Betty Nguyen
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Annamaria Griguoli
- Neurogenetics Unit and Rare Disease Centre, IRCCS Neuromed Pozzilli (IS), Pozzilli, Italy
| | - Colin J Ross
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ferdinando Squitieri
- Neurogenetics Unit and Rare Disease Centre, IRCCS Neuromed Pozzilli (IS), Pozzilli, Italy
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada.
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5
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Bečanović K, Nørremølle A, Neal SJ, Kay C, Collins JA, Arenillas D, Lilja T, Gaudenzi G, Manoharan S, Doty CN, Beck J, Lahiri N, Portales-Casamar E, Warby SC, Connolly C, De Souza RAG, Tabrizi SJ, Hermanson O, Langbehn DR, Hayden MR, Wasserman WW, Leavitt BR. A SNP in the HTT promoter alters NF-κB binding and is a bidirectional genetic modifier of Huntington disease. Nat Neurosci 2015; 18:807-16. [PMID: 25938884 DOI: 10.1038/nn.4014] [Citation(s) in RCA: 79] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 04/06/2015] [Indexed: 12/11/2022]
Abstract
Cis-regulatory variants that alter gene expression can modify disease expressivity, but none have previously been identified in Huntington disease (HD). Here we provide in vivo evidence in HD patients that cis-regulatory variants in the HTT promoter are bidirectional modifiers of HD age of onset. HTT promoter analysis identified a NF-κB binding site that regulates HTT promoter transcriptional activity. A non-coding SNP, rs13102260:G > A, in this binding site impaired NF-κB binding and reduced HTT transcriptional activity and HTT protein expression. The presence of the rs13102260 minor (A) variant on the HD disease allele was associated with delayed age of onset in familial cases, whereas the presence of the rs13102260 (A) variant on the wild-type HTT allele was associated with earlier age of onset in HD patients in an extreme case-based cohort. Our findings suggest a previously unknown mechanism linking allele-specific effects of rs13102260 on HTT expression to HD age of onset and have implications for HTT silencing treatments that are currently in development.
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Affiliation(s)
- Kristina Bečanović
- 1] Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada. [2] Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Anne Nørremølle
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Scott J Neal
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Chris Kay
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jennifer A Collins
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - David Arenillas
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Tobias Lilja
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Giulia Gaudenzi
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Shiana Manoharan
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jessalyn Beck
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Nayana Lahiri
- UCL Institute of Neurology, University College London, London, UK
| | - Elodie Portales-Casamar
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Simon C Warby
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Colúm Connolly
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rebecca A G De Souza
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sarah J Tabrizi
- UCL Institute of Neurology, University College London, London, UK
| | - Ola Hermanson
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Douglas R Langbehn
- Department of Psychiatry and Biostatistics, University of Iowa, Iowa City, Iowa, USA
| | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Wyeth W Wasserman
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Blair R Leavitt
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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6
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Southwell AL, Skotte NH, Caron N, Kordasiewicz H, Oestergaard M, Doty CN, Villanueva EB, Xie Y, Felczak B, Freier SM, Swayze EE, Seth PP, Frank Bennet C, Hayden MR. 696. Pre-Clinical Evaluation of Allele-Specific Mutant Huntingtin Gene Silencing Antisense Oligonucleotides. Mol Ther 2015. [DOI: 10.1016/s1525-0016(16)34305-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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7
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Mattis VB, Tom C, Akimov S, Saeedian J, Østergaard ME, Southwell AL, Doty CN, Ornelas L, Sahabian A, Lenaeus L, Mandefro B, Sareen D, Arjomand J, Hayden MR, Ross CA, Svendsen CN. HD iPSC-derived neural progenitors accumulate in culture and are susceptible to BDNF withdrawal due to glutamate toxicity. Hum Mol Genet 2015; 24:3257-71. [PMID: 25740845 DOI: 10.1093/hmg/ddv080] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 03/02/2015] [Indexed: 12/12/2022] Open
Abstract
Huntington's disease (HD) is a fatal neurodegenerative disease, caused by expansion of polyglutamine repeats in the Huntingtin gene, with longer expansions leading to earlier ages of onset. The HD iPSC Consortium has recently reported a new in vitro model of HD based on the generation of induced pluripotent stem cells (iPSCs) from HD patients and controls. The current study has furthered the disease in a dish model of HD by generating new non-integrating HD and control iPSC lines. Both HD and control iPSC lines can be efficiently differentiated into neurons/glia; however, the HD-derived cells maintained a significantly greater number of nestin-expressing neural progenitor cells compared with control cells. This cell population showed enhanced vulnerability to brain-derived neurotrophic factor (BDNF) withdrawal in the juvenile-onset HD (JHD) lines, which appeared to be CAG repeat-dependent and mediated by the loss of signaling from the TrkB receptor. It was postulated that this increased death following BDNF withdrawal may be due to glutamate toxicity, as the N-methyl-d-aspartate (NMDA) receptor subunit NR2B was up-regulated in the cultures. Indeed, blocking glutamate signaling, not just through the NMDA but also mGlu and AMPA/Kainate receptors, completely reversed the cell death phenotype. This study suggests that the pathogenesis of JHD may involve in part a population of 'persistent' neural progenitors that are selectively vulnerable to BDNF withdrawal. Similar results were seen in adult hippocampal-derived neural progenitors isolated from the BACHD model mouse. Together, these results provide important insight into HD mechanisms at early developmental time points, which may suggest novel approaches to HD therapeutics.
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Affiliation(s)
- Virginia B Mattis
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Colton Tom
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Sergey Akimov
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jasmine Saeedian
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | | | - Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada and
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada and
| | - Loren Ornelas
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Anais Sahabian
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Lindsay Lenaeus
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Berhan Mandefro
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | - Dhruv Sareen
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
| | | | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada and
| | - Christopher A Ross
- Division of Neurobiology, Department of Psychiatry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Clive N Svendsen
- The Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, 8700 Beverly Blvd, 8400 AHSP, Los Angeles, CA 90048, USA
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8
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Southwell AL, Skotte NH, Kordasiewicz HB, Østergaard ME, Watt AT, Carroll JB, Doty CN, Villanueva EB, Petoukhov E, Vaid K, Xie Y, Freier SM, Swayze EE, Seth PP, Bennett CF, Hayden MR. In vivo evaluation of candidate allele-specific mutant huntingtin gene silencing antisense oligonucleotides. Mol Ther 2014; 22:2093-2106. [PMID: 25101598 PMCID: PMC4429695 DOI: 10.1038/mt.2014.153] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Accepted: 07/23/2014] [Indexed: 11/08/2022] Open
Abstract
Huntington disease (HD) is a dominant, genetic neurodegenerative disease characterized by progressive loss of voluntary motor control, psychiatric disturbance, and cognitive decline, for which there is currently no disease-modifying therapy. HD is caused by the expansion of a CAG tract in the huntingtin (HTT) gene. The mutant HTT protein (muHTT) acquires toxic functions, and there is significant evidence that muHTT lowering would be therapeutically efficacious. However, the wild-type HTT protein (wtHTT) serves vital functions, making allele-specific muHTT lowering strategies potentially safer than nonselective strategies. CAG tract expansion is associated with single nucleotide polymorphisms (SNPs) that can be targeted by gene silencing reagents such as antisense oligonucleotides (ASOs) to accomplish allele-specific muHTT lowering. Here we evaluate ASOs targeted to HD-associated SNPs in acute in vivo studies including screening, distribution, duration of action and dosing, using a humanized mouse model of HD, Hu97/18, that is heterozygous for the targeted SNPs. We have identified four well-tolerated lead ASOs that potently and selectively silence muHTT at a broad range of doses throughout the central nervous system for 16 weeks or more after a single intracerebroventricular (ICV) injection. With further validation, these ASOs could provide a therapeutic option for individuals afflicted with HD.
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Affiliation(s)
- Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Niels H Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | | | - Jeffrey B Carroll
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, Washington, USA
| | - Crystal N Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Erika B Villanueva
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eugenia Petoukhov
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kuljeet Vaid
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Yuanyun Xie
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | | | | | - Michael R Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada.
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9
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Skotte NH, Southwell AL, Østergaard ME, Carroll JB, Warby SC, Doty CN, Petoukhov E, Vaid K, Kordasiewicz H, Watt AT, Freier SM, Hung G, Seth PP, Bennett CF, Swayze EE, Hayden MR. Allele-specific suppression of mutant huntingtin using antisense oligonucleotides: providing a therapeutic option for all Huntington disease patients. PLoS One 2014; 9:e107434. [PMID: 25207939 PMCID: PMC4160241 DOI: 10.1371/journal.pone.0107434] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/11/2014] [Indexed: 01/10/2023] Open
Abstract
Huntington disease (HD) is an inherited, fatal neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin gene. The mutant protein causes neuronal dysfunction and degeneration resulting in motor dysfunction, cognitive decline, and psychiatric disturbances. Currently, there is no disease altering treatment, and symptomatic therapy has limited benefit. The pathogenesis of HD is complicated and multiple pathways are compromised. Addressing the problem at its genetic root by suppressing mutant huntingtin expression is a promising therapeutic strategy for HD. We have developed and evaluated antisense oligonucleotides (ASOs) targeting single nucleotide polymorphisms that are significantly enriched on HD alleles (HD-SNPs). We describe our structure-activity relationship studies for ASO design and find that adjusting the SNP position within the gap, chemical modifications of the wings, and shortening the unmodified gap are critical for potent, specific, and well tolerated silencing of mutant huntingtin. Finally, we show that using two distinct ASO drugs targeting the two allelic variants of an HD-SNP could provide a therapeutic option for all persons with HD; allele-specifically for roughly half, and non-specifically for the remainder.
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Affiliation(s)
- Niels H. Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amber L. Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Jeffrey B. Carroll
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, Washington, United States of America
| | - Simon C. Warby
- Center for Advanced Research in Sleep Medicine, Department of Psychiatry, University of Montréal, Montréal, Quebec, Canada
| | - Crystal N. Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eugenia Petoukhov
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kuljeet Vaid
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Andrew T. Watt
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Susan M. Freier
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Gene Hung
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Punit P. Seth
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - C. Frank Bennett
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Eric E. Swayze
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Michael R. Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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10
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Parsons MP, Kang R, Buren C, Dau A, Southwell AL, Doty CN, Sanders SS, Hayden MR, Raymond LA. Bidirectional control of postsynaptic density-95 (PSD-95) clustering by Huntingtin. J Biol Chem 2013; 289:3518-28. [PMID: 24347167 DOI: 10.1074/jbc.m113.513945] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Huntington disease is associated with early alterations in corticostriatal synaptic function that precede cell death, and it is postulated that ameliorating such changes may delay clinical onset and/or prevent neurodegeneration. Although many of these synaptic alterations are thought to be attributable to a toxic gain of function of the mutant huntingtin protein, the role that nonpathogenic huntingtin (HTT) plays in synaptic function is relatively unexplored. Here, we compare the immunocytochemical localization of a major postsynaptic scaffolding protein, PSD-95, in striatal neurons from WT mice and mice overexpressing HTT with 18 glutamine repeats (YAC18, nonpathogenic). We found that HTT overexpression resulted in a palmitoylation- and BDNF-dependent increase in PSD-95 clustering at synaptic sites in striatal spiny projection neurons (SPNs) co-cultured with cortical neurons. Surprisingly, the latter effect was mediated presynaptically, as HTT overexpression in cortical neurons alone was sufficient to increase PSD-95 clustering in the postsynaptic SPNs. In contrast, antisense oligonucleotide knockdown of HTT in WT co-cultures resulted in a significant reduction of PSD-95 clustering in SPNs. Notably, despite these bidirectional changes in PSD-95 clustering, we did not observe an alteration in basal electrophysiological measures of AMPA and NMDA receptors. Thus, unlike in previous studies in the hippocampus, enhanced or decreased PSD-95 clustering alone was insufficient to drive AMPA or NMDA receptors into or out of SPN synapses. In all, our results demonstrate that nonpathogenic HTT can indeed influence synaptic protein localization and uncover a novel role of HTT in PSD-95 distribution.
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Affiliation(s)
- Matthew P Parsons
- From the Department of Psychiatry and Brain Research Centre, University of British Columbia, Vancouver, British Columbia V6T 1Z3 and
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11
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Semaka A, Kay C, Doty CN, Collins JA, Tam N, Hayden MR. High frequency of intermediate alleles on Huntington disease-associated haplotypes in British Columbia's general population. Am J Med Genet B Neuropsychiatr Genet 2013; 162B:864-71. [PMID: 24038799 DOI: 10.1002/ajmg.b.32193] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 07/11/2013] [Indexed: 11/08/2022]
Abstract
Intermediate alleles (27-35 CAG, IAs) for Huntington disease (HD) usually do not confer the disease phenotype but are prone to CAG repeat instability. Consequently, offspring are at-risk of inheriting an expanded allele in the HD range (≥36 CAG). IAs that expand into a new mutation have been hypothesized to be more susceptible to instability compared to IAs identified on the non-HD side of a family from the general population. Frequency estimates for IAs are limited and have largely been determined using clinical samples of HD or related disorders, which may result in an ascertainment bias. This study aimed to establish the frequency of IAs in a sample of a British Columbia's (B.C.) general population with no known association to HD and examine the haplotype of new mutation and general population IAs. CAG sizing was performed on 1,600 DNA samples from B.C.'s general population. Haplotypes were determined using 22 tagging SNPs across the HTT gene. 5.8% of individuals were found to have an IA, of which 60% were on HD-associated haplotypes. There was no difference in the haplotype distribution of new mutation and general population IAs. These findings suggest that IAs are relatively frequent in the general population and are often found on haplotypes associated with expanded CAG lengths. There is likely no difference in the propensity of new mutation and general population IAs to expand into the disease range given that they are both found on disease-associated haplotypes. These findings have important implications for clinical practice.
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Affiliation(s)
- Alicia Semaka
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, Canada
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12
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Østergaard ME, Southwell AL, Kordasiewicz H, Watt AT, Skotte NH, Doty CN, Vaid K, Villanueva EB, Swayze EE, Bennett CF, Hayden MR, Seth PP. Rational design of antisense oligonucleotides targeting single nucleotide polymorphisms for potent and allele selective suppression of mutant Huntingtin in the CNS. Nucleic Acids Res 2013; 41:9634-50. [PMID: 23963702 PMCID: PMC3834808 DOI: 10.1093/nar/gkt725] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Autosomal dominant diseases such as Huntington’s disease (HD) are caused by a gain of function mutant protein and/or RNA. An ideal treatment for these diseases is to selectively suppress expression of the mutant allele while preserving expression of the wild-type variant. RNase H active antisense oligonucleotides (ASOs) or small interfering RNAs can achieve allele selective suppression of gene expression by targeting single nucleotide polymorphisms (SNPs) associated with the repeat expansion. ASOs have been previously shown to discriminate single nucleotide changes in targeted RNAs with ∼5-fold selectivity. Based on RNase H enzymology, we enhanced single nucleotide discrimination by positional incorporation of chemical modifications within the oligonucleotide to limit RNase H cleavage of the non-targeted transcript. The resulting oligonucleotides demonstrate >100-fold discrimination for a single nucleotide change at an SNP site in the disease causing huntingtin mRNA, in patient cells and in a completely humanized mouse model of HD. The modified ASOs were also well tolerated after injection into the central nervous system of wild-type animals, suggesting that their tolerability profile is suitable for advancement as potential allele-selective HD therapeutics. Our findings lay the foundation for efficient allele-selective downregulation of gene expression using ASOs—an outcome with broad application to HD and other dominant genetic disorders.
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Affiliation(s)
- Michael E Østergaard
- Isis Pharmaceuticals, 2855 Gazelle Court, Carlsbad, CA 92010, USA and Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, V5Z 4H4, Canada
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13
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Baine FK, Kay C, Ketelaar ME, Collins JA, Semaka A, Doty CN, Krause A, Greenberg LJ, Hayden MR. Huntington disease in the South African population occurs on diverse and ethnically distinct genetic haplotypes. Eur J Hum Genet 2013; 21:1120-7. [PMID: 23463025 DOI: 10.1038/ejhg.2013.2] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/12/2012] [Accepted: 12/28/2012] [Indexed: 11/09/2022] Open
Abstract
Huntington disease (HD) is a neurodegenerative disorder resulting from the expansion of a CAG trinucleotide repeat in the huntingtin (HTT) gene. Worldwide prevalence varies geographically with the highest figures reported in populations of European ancestry. HD in South Africa has been reported in Caucasian, black and mixed subpopulations, with similar estimated prevalence in the Caucasian and mixed groups and a lower estimate in the black subpopulation. Recent studies have associated specific HTT haplotypes with HD in distinct populations. Expanded HD alleles in Europe occur predominantly on haplogroup A (specifically high-risk variants A1/A2), whereas in East Asian populations, HD alleles are associated with haplogroup C. Whether specific HTT haplotypes associate with HD in black Africans and how these compare with haplotypes found in European and East Asian populations remains unknown. The current study genotyped the HTT region in unaffected individuals and HD patients from each of the South African subpopulations, and haplotypes were constructed. CAG repeat sizes were determined and phased to haplotype. Results indicate that HD alleles from Caucasian and mixed patients are predominantly associated with haplogroup A, signifying a similar European origin for HD. However, in black patients, HD occurs predominantly on haplogroup B, suggesting several distinct origins of the mutation in South Africa. The absence of high-risk variants (A1/A2) in the black subpopulation may also explain the reported low prevalence of HD. Identification of haplotypes associated with HD-expanded alleles is particularly relevant to the development of population-specific therapeutic targets for selective suppression of the expanded HTT transcript.
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Affiliation(s)
- Fiona K Baine
- 1] Division of Human Genetics, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa [2] Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Sutton LM, Sanders SS, Butland SL, Singaraja RR, Franciosi S, Southwell AL, Doty CN, Schmidt ME, Mui KKN, Kovalik V, Young FB, Zhang W, Hayden MR. Hip14l-deficient mice develop neuropathological and behavioural features of Huntington disease. Hum Mol Genet 2013; 22:452-65. [PMID: 23077216 DOI: 10.1093/hmg/dds441] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Palmitoylation, the dynamic post-translational addition of the lipid, palmitate, to proteins by Asp-His-His-Cys-containing palmitoyl acyltransferase (PAT) enzymes, modulates protein function and localization and plays a key role in the nervous system. Huntingtin-interacting protein 14 (HIP14), a well-characterized neuronal PAT, has been implicated in the pathogenesis of Huntington disease (HD), a fatal neurodegenerative disease associated with motor, psychiatric and cognitive symptoms, caused by a CAG expansion in the huntingtin gene (HTT). Mice deficient for Hip14 expression develop neuropathological and behavioural features similar to HD, and the catalytic activity of HIP14 is impaired in HD mice, most likely due to the reduced interaction of HIP14 with HTT. Huntingtin-interacting protein 14-like (HIP14L) is a paralog of HIP14, with identical domain structure. Together, HIP14 and HIP14L are the major PATs for HTT. Here, we report the characterization of a Hip14l-deficient mouse model, which develops adult-onset, widespread and progressive neuropathology accompanied by early motor deficits in climbing, impaired motor learning and reduced palmitoylation of a novel HIP14L substrate: SNAP25. Although the phenotype resembles that of the Hip14(-/-) mice, a more progressive phenotype, similar to that of the YAC128 transgenic mouse model of HD, is observed. In addition, HIP14L interacts less with mutant HTT than the wild-type protein, suggesting that reduced HIP14L-dependent palmitoylation of neuronal substrates may contribute to the pathogenesis of HD. Thus, both HIP14 and HIP14L may be dysfunctional in the disease.
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Affiliation(s)
- Liza M Sutton
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, British Columbia V5Z 4H4, Canada
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15
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Southwell AL, Warby SC, Carroll JB, Doty CN, Skotte NH, Zhang W, Villanueva EB, Kovalik V, Xie Y, Pouladi MA, Collins JA, Yang XW, Franciosi S, Hayden MR. A fully humanized transgenic mouse model of Huntington disease. Hum Mol Genet 2012; 22:18-34. [PMID: 23001568 DOI: 10.1093/hmg/dds397] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Silencing the mutant huntingtin gene (muHTT) is a direct and simple therapeutic strategy for the treatment of Huntington disease (HD) in principle. However, targeting the HD mutation presents challenges because it is an expansion of a common genetic element (a CAG tract) that is found throughout the genome. Moreover, the HTT protein is important for neuronal health throughout life, and silencing strategies that also reduce the wild-type HTT allele may not be well tolerated during the long-term treatment of HD. Several HTT silencing strategies are in development that target genetic sites in HTT that are outside of the CAG expansion, including HD mutation-linked single-nucleotide polymorphisms and the HTT promoter. Preclinical testing of these genetic therapies has required the development of a new mouse model of HD that carries these human-specific genetic targets. To generate a fully humanized mouse model of HD, we have cross-bred BACHD and YAC18 on the Hdh(-/-) background. The resulting line, Hu97/18, is the first murine model of HD that fully genetically recapitulates human HD having two human HTT genes, no mouse Hdh genes and heterozygosity of the HD mutation. We find that Hu97/18 mice display many of the behavioral changes associated with HD including motor, psychiatric and cognitive deficits, as well as canonical neuropathological abnormalities. This mouse line will be useful for gaining additional insights into the disease mechanisms of HD as well as for testing genetic therapies targeting human HTT.
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Affiliation(s)
- Amber L Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, BC, Canada V5Z 4H4
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16
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Carroll JB, Warby SC, Southwell AL, Doty CN, Greenlee S, Skotte N, Hung G, Bennett CF, Freier SM, Hayden MR. Potent and selective antisense oligonucleotides targeting single-nucleotide polymorphisms in the Huntington disease gene / allele-specific silencing of mutant huntingtin. Mol Ther 2011; 19:2178-85. [PMID: 21971427 DOI: 10.1038/mt.2011.201] [Citation(s) in RCA: 211] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Huntington disease (HD) is an autosomal dominant neurodegenerative disorder caused by CAG-expansion in the huntingtin gene (HTT) that results in a toxic gain of function in the mutant huntingtin protein (mHTT). Reducing the expression of mHTT is therefore an attractive therapy for HD. However, wild-type HTT protein is essential for development and has critical roles in maintaining neuronal health. Therapies for HD that reduce wild-type HTT may therefore generate unintended negative consequences. We have identified single-nucleotide polymorphism (SNP) targets in the human HD population for the disease-specific targeting of the HTT gene. Using primary cells from patients with HD and the transgenic YAC18 and BACHD mouse lines, we developed antisense oligonucleotide (ASO) molecules that potently and selectively silence mHTT at both exonic and intronic SNP sites. Modification of these ASOs with S-constrained-ethyl (cET) motifs significantly improves potency while maintaining allele selectively in vitro. The developed ASO is potent and selective for mHTT in vivo after delivery to the mouse brain. We demonstrate that potent and selective allele-specific knockdown of the mHTT protein can be achieved at therapeutically relevant SNP sites using ASOs in vitro and in vivo.
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Affiliation(s)
- Jeffrey B Carroll
- Program in Neuroscience, Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
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Affiliation(s)
- C N Doty
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, 950 West 28th Avenue, Vancouver, BC, Canada V5Z 4H4.
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Warby SC, Doty CN, Graham RK, Shively J, Singaraja RR, Hayden MR. Phosphorylation of huntingtin reduces the accumulation of its nuclear fragments. Mol Cell Neurosci 2009; 40:121-7. [DOI: 10.1016/j.mcn.2008.09.007] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2008] [Revised: 09/18/2008] [Accepted: 09/25/2008] [Indexed: 01/04/2023] Open
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Warby SC, Doty CN, Graham RK, Carroll JB, Yang YZ, Singaraja RR, Overall CM, Hayden MR. Activated caspase-6 and caspase-6-cleaved fragments of huntingtin specifically colocalize in the nucleus. Hum Mol Genet 2008; 17:2390-404. [PMID: 18445618 DOI: 10.1093/hmg/ddn139] [Citation(s) in RCA: 101] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Proteolysis of mutant huntingtin is crucial to the development of Huntington disease (HD). Specifically preventing proteolysis at the capase-6 (C6) consensus sequence at amino acid 586 of mutant huntingtin prevents the development of behavioural, motor and neuropathological features in a mouse model of HD. However, the mechanism underlying the selective toxicity of the 586 amino acid cleavage event is currently unknown. We have examined the subcellular localization of different caspase proteolytic fragments of huntingtin using neo-epitope antibodies. Our data suggest that the nucleus is the primary site of htt cleavage at amino acid 586. Endogenously cleaved 586 amino acid fragments are enriched in the nucleus of immortalized striatal cells and primary striatal neurons where they co-localize with active C6. Cell stress induced by staurosporine results in the nuclear translocation and activation of C6 and an increase in 586 amino acid fragments of huntingtin in the nucleus. In comparison, endogenous caspase-2/3-generated huntingtin 552 amino acid fragments localize to the perinuclear region. The different cellular itineraries of endogenously generated caspase products of huntingtin may provide an explanation for the selective toxicity of huntingtin fragments cleaved at amino acid 586.
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Affiliation(s)
- Simon C Warby
- Centre for Molecular Medicine and Therapeutics, University of British Columbia, 980 West 28th Avenue,Vancouver, British Columbia, Canada
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Graham RK, Deng Y, Slow EJ, Haigh B, Bissada N, Lu G, Pearson J, Shehadeh J, Bertram L, Murphy Z, Warby SC, Doty CN, Roy S, Wellington CL, Leavitt BR, Raymond LA, Nicholson DW, Hayden MR. Cleavage at the caspase-6 site is required for neuronal dysfunction and degeneration due to mutant huntingtin. Cell 2006; 125:1179-91. [PMID: 16777606 DOI: 10.1016/j.cell.2006.04.026] [Citation(s) in RCA: 477] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Revised: 01/29/2006] [Accepted: 04/03/2006] [Indexed: 11/24/2022]
Abstract
Cleavage of huntingtin (htt) has been characterized in vitro, and accumulation of caspase cleavage fragments represents an early pathological change in brains of Huntington's disease (HD) patients. However, the relationship between htt proteolysis and the pathogenesis of HD is unknown. To determine whether caspase cleavage of htt is a key event in the neuronal dysfunction and selective neurodegeneration in HD, we generated YAC mice expressing caspase-3- and caspase-6-resistant mutant htt. Mice expressing mutant htt, resistant to cleavage by caspase-6 but not caspase-3, maintain normal neuronal function and do not develop striatal neurodegeneration. Furthermore, caspase-6-resistant mutant htt mice are protected against neurotoxicity induced by multiple stressors including NMDA, quinolinic acid (QA), and staurosporine. These results are consistent with proteolysis of htt at the caspase-6 cleavage site being an important event in mediating neuronal dysfunction and neurodegeneration and highlight the significant role of htt proteolysis and excitotoxicity in HD.
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Affiliation(s)
- Rona K Graham
- Department of Medical Genetics, Centre for Molecular Medicine and Therapeutics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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