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Bondulich MK, Phillips J, Cañibano-Pico M, Nita IM, Byrne LM, Wild EJ, Bates GP. Translatable plasma and CSF biomarkers for use in mouse models of Huntington's disease. Brain Commun 2024; 6:fcae030. [PMID: 38370446 PMCID: PMC10873584 DOI: 10.1093/braincomms/fcae030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 12/14/2023] [Accepted: 02/05/2024] [Indexed: 02/20/2024] Open
Abstract
Huntington's disease is an inherited neurodegenerative disorder for which a wide range of disease-modifying therapies are in development and the availability of biomarkers to monitor treatment response is essential for the success of clinical trials. Baseline levels of neurofilament light chain in CSF and plasma have been shown to be effective in predicting clinical disease status, subsequent clinical progression and brain atrophy. The identification of further sensitive prognostic fluid biomarkers is an active research area, and total-Tau and YKL-40 levels have been shown to be increased in CSF from Huntington's disease mutation carriers. The use of readouts with clinical utility in the preclinical assessment of potential therapeutics should aid in the translation of new treatments. Here, we set out to determine how the concentrations of these three proteins change in plasma and CSF with disease progression in representative, well-established mouse models of Huntington's disease. Plasma and CSF were collected throughout disease progression from R6/2 transgenic mice with CAG repeats of 200 or 90 codons (R6/2:Q200 and R6/2:Q90), zQ175 knock-in mice and YAC128 transgenic mice, along with their respective wild-type littermates. Neurofilament light chain and total-Tau concentrations were quantified in CSF and plasma using ultrasensitive single-molecule array (Quanterix) assays, and a novel Quanterix assay was developed for breast regression protein 39 (mouse homologue of YKL-40) and used to quantify breast regression protein 39 levels in plasma. CSF levels of neurofilament light chain and plasma levels of neurofilament light chain and breast regression protein 39 increased in wild-type biofluids with age, whereas total-Tau remained constant. Neurofilament light chain and breast regression protein 39 were elevated in the plasma and CSF from Huntington's disease mouse models, as compared with wild-type littermates, at presymptomatic stages, whereas total-Tau was only increased at the latest disease stages analysed. Levels of biomarkers that had been measured in the same CSF or plasma samples taken at the latest stages of disease were correlated. The demonstration that breast regression protein 39 constitutes a robust plasma biomarker in Huntington's disease mouse models supports the further investigation of YKL-40 as a CSF biomarker for Huntington's disease mutation carriers. Neurofilament light chain and Tau are considered markers of neuronal damage, and breast regression protein 39 is a marker of inflammation; the similarities and differences in the levels of these proteins between mouse models may provide future insights into their underlying pathology. These data will facilitate the use of fluid biomarkers in the preclinical assessment of therapeutic agents for Huntington's disease, providing readouts with direct relevance to clinical trials.
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Affiliation(s)
- Marie K Bondulich
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Jemima Phillips
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - María Cañibano-Pico
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Iulia M Nita
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Lauren M Byrne
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Edward J Wild
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Gillian P Bates
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
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Samra K, MacDougall AM, Bouzigues A, Bocchetta M, Cash DM, Greaves CV, Convery RS, Hardy C, van Swieten JC, Seelaar H, Jiskoot LC, Moreno F, Sanchez-Valle R, Laforce R, Graff C, Masellis M, Tartaglia MC, Rowe JB, Borroni B, Finger E, Synofzik M, Galimberti D, Vandenberghe R, de Mendonça A, Butler CR, Gerhard A, Ducharme S, Le Ber I, Santana I, Pasquier F, Levin J, Otto M, Sorbi S, Warren JD, Rohrer JD, Russell LL. Genetic forms of primary progressive aphasia within the GENetic Frontotemporal dementia Initiative (GENFI) cohort: comparison with sporadic primary progressive aphasia. Brain Commun 2023; 5:fcad036. [PMID: 36938528 PMCID: PMC10019761 DOI: 10.1093/braincomms/fcad036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 08/26/2022] [Accepted: 02/15/2023] [Indexed: 02/19/2023] Open
Abstract
Primary progressive aphasia is most commonly a sporadic disorder, but in some cases, it can be genetic. This study aimed to understand the clinical, cognitive and imaging phenotype of the genetic forms of primary progressive aphasia in comparison to the canonical nonfluent, semantic and logopenic subtypes seen in sporadic disease. Participants with genetic primary progressive aphasia were recruited from the international multicentre GENetic Frontotemporal dementia Initiative study and compared with healthy controls as well as a cohort of people with sporadic primary progressive aphasia. Symptoms were assessed using the GENetic Frontotemporal dementia Initiative language, behavioural, neuropsychiatric and motor scales. Participants also underwent a cognitive assessment and 3 T volumetric T1-weighted MRI. One C9orf72 (2%), 1 MAPT (6%) and 17 GRN (44%) symptomatic mutation carriers had a diagnosis of primary progressive aphasia. In the GRN cohort, 47% had a diagnosis of nonfluent variant primary progressive aphasia, and 53% had a primary progressive aphasia syndrome that did not fit diagnostic criteria for any of the three subtypes, called primary progressive aphasia-not otherwise specified here. The phenotype of the genetic nonfluent variant primary progressive aphasia group largely overlapped with that of sporadic nonfluent variant primary progressive aphasia, although the presence of an associated atypical parkinsonian syndrome was characteristic of sporadic and not genetic disease. The primary progressive aphasia -not otherwise specified group however was distinct from the sporadic subtypes with impaired grammar/syntax in the presence of relatively intact articulation, alongside other linguistic deficits. The pattern of atrophy seen on MRI in the genetic nonfluent variant primary progressive aphasia group overlapped with that of the sporadic nonfluent variant primary progressive aphasia cohort, although with more posterior cortical involvement, whilst the primary progressive aphasia-not otherwise specified group was strikingly asymmetrical with involvement particularly of the insula and dorsolateral prefrontal cortex but also atrophy of the orbitofrontal cortex and the medial temporal lobes. Whilst there are overlapping symptoms between genetic and sporadic primary progressive aphasia syndromes, there are also distinct features. Future iterations of the primary progressive aphasia consensus criteria should encompass such information with further research needed to understand the earliest features of these disorders, particularly during the prodromal period of genetic disease.
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Affiliation(s)
- Kiran Samra
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Amy M MacDougall
- Department of Medical Statistics, London School of Hygiene and Tropical Medicine, London, UK
| | - Arabella Bouzigues
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Martina Bocchetta
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - David M Cash
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Caroline V Greaves
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Rhian S Convery
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Chris Hardy
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | | | - Harro Seelaar
- Department of Neurology, Erasmus Medical Centre, Rotterdam, Netherlands
| | - Lize C Jiskoot
- Department of Neurology, Erasmus Medical Centre, Rotterdam, Netherlands
| | - Fermin Moreno
- Cognitive Disorders Unit, Department of Neurology, Donostia Universitary Hospital, San Sebastian, Spain
- Neuroscience Area, Biodonostia Health Research Institute, San Sebastian, Gipuzkoa, Spain
| | - Raquel Sanchez-Valle
- Alzheimer’s disease and Other Cognitive Disorders Unit, Neurology Service, Hospital Clínic, Institut d’Investigacións Biomèdiques August Pi I Sunyer, University of Barcelona, Barcelona, Spain
| | - Robert Laforce
- Clinique Interdisciplinaire de Mémoire, Département des Sciences Neurologiques, CHU de Québec, and Faculté de Médecine, Université Laval, Québec City, Canada
| | - Caroline Graff
- Center for Alzheimer Research, Division of Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Bioclinicum, Karolinska Institutet, Solna, Sweden
- Unit for Hereditary Dementias, Theme Aging, Karolinska University Hospital, Solna, Sweden
| | - Mario Masellis
- Sunnybrook Health Sciences Centre, Sunnybrook Research Institute, University of Toronto, Toronto, Canada
| | - Maria Carmela Tartaglia
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, ON, Canada
| | - James B Rowe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Barbara Borroni
- Neurology Unit, Department of Clinical and Experimental Sciences, University of Brescia, Brescia, Italy
| | - Elizabeth Finger
- Department of Clinical Neurological Sciences, University of Western Ontario, London, ON, Canada
| | - Matthis Synofzik
- Department of Neurodegenerative Diseases, Hertie-Institute for Clinical Brain Research and Center of Neurology, University of Tübingen, Tübingen, Germany
- Centre for Neurodegenerative Diseases (DZNE), Tübingen, Germany
| | - Daniela Galimberti
- Fondazione Ca’ Granda, IRCCS Ospedale Policlinico, Milan, Italy
- University of Milan, Centro Dino Ferrari, Milan, Italy
| | - Rik Vandenberghe
- Laboratory for Cognitive Neurology, Department of Neurosciences, KU Leuven, Leuven, Belgium
- Neurology Service, University Hospitals Leuven, Leuven, Belgium
- Leuven Brain Institute, KU Leuven, Leuven, Belgium
| | - Alexandre de Mendonça
- Laboratory of Neurosciences, Institute of Molecular Medicine, Faculty of Medicine, University of Lisbon, Lisbon, Portugal
| | - Chris R Butler
- Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, UK
- Department of Brain Sciences, Imperial College London, London, UK
| | - Alexander Gerhard
- Division of Neuroscience and Experimental Psychology, Wolfson Molecular Imaging Centre, University of Manchester, Manchester, UK
- Departments of Geriatric Medicine and Nuclear Medicine, University of Duisburg-Essen, Germany
| | - Simon Ducharme
- Department of Psychiatry, McGill University Health Centre, McGill University, Montreal, Québec, Canada
- McConnell Brain Imaging Centre, Montreal Neurological Institute, McGill University, Montreal, Québec, Canada
| | - Isabelle Le Ber
- Sorbonne Université, Paris Brain Institute – Institut du Cerveau – ICM, Inserm U1127, CNRS UMR 7225, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
- Centre de référence des démences rares ou précoces, IM2A, Département de Neurologie, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
- Département de Neurologie, AP-HP - Hôpital Pitié-Salpêtrière, Paris, France
| | - Isabel Santana
- University Hospital of Coimbra (HUC), Neurology Service, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
- Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Florence Pasquier
- Univ Lille, Inserm 1172, Lille, France
- Inserm 1172, Lille, France
- CHU, CNR-MAJ, Labex Distalz, LiCEND Lille, France
| | - Johannes Levin
- Department of Neurology, Ludwig-Maximilians Universität München, Munich, Germany
- German Centre for Neurodegenerative Diseases (DZNE), Munich, Germany
- Munich Cluster of Systems Neurology (SyNergy), Munich, Germany
| | - Markus Otto
- Department of Neurology, University of Ulm, Ulm, Germany
| | - Sandro Sorbi
- Department of Neurofarba, University of Florence, Florence, Italy
- IRCCS Fondazione Don Carlo Gnocchi, Florence, Italy
| | - Jason D Warren
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Jonathan D Rohrer
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
| | - Lucy L Russell
- Dementia Research Centre, Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London, UK
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Smith EJ, Sathasivam K, Landles C, Osborne GF, Mason MA, Gomez-Paredes C, Taxy BA, Milton RE, Ast A, Schindler F, Zhang C, Duan W, Wanker EE, Bates GP. Early detection of exon 1 huntingtin aggregation in zQ175 brains by molecular and histological approaches. Brain Commun 2023; 5:fcad010. [PMID: 36756307 PMCID: PMC9901570 DOI: 10.1093/braincomms/fcad010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 10/08/2022] [Accepted: 01/18/2023] [Indexed: 01/21/2023] Open
Abstract
Huntingtin-lowering approaches that target huntingtin expression are a major focus for therapeutic intervention for Huntington's disease. When the cytosine, adenine and guanine repeat is expanded, the huntingtin pre-mRNA is alternatively processed to generate the full-length huntingtin and HTT1a transcripts. HTT1a encodes the aggregation-prone and highly pathogenic exon 1 huntingtin protein. In evaluating huntingtin-lowering approaches, understanding how the targeting strategy modulates levels of both transcripts and the huntingtin protein isoforms that they encode will be essential. Given the aggregation-propensity of exon 1 huntingtin, the impact of a given strategy on the levels and subcellular location of aggregated huntingtin will need to be determined. We have developed and applied sensitive molecular approaches to monitor the levels of aggregated and soluble huntingtin isoforms in tissue lysates. We have used these, in combination with immunohistochemistry, to map the appearance and accumulation of aggregated huntingtin throughout the CNS of zQ175 mice, a model of Huntington's disease frequently chosen for preclinical studies. Aggregation analyses were performed on tissues from zQ175 and wild-type mice at monthly intervals from 1 to 6 months of age. We developed three homogeneous time-resolved fluorescence assays to track the accumulation of aggregated huntingtin and showed that two of these were specific for the exon 1 huntingtin protein. Collectively, the homogeneous time-resolved fluorescence assays detected huntingtin aggregation in the 10 zQ175 CNS regions by 1-2 months of age. Immunohistochemistry with the polyclonal S830 anti-huntingtin antibody showed that nuclear huntingtin aggregation, in the form of a diffuse nuclear immunostain, could be visualized in the striatum, hippocampal CA1 region and layer IV of the somatosensory cortex by 2 months. That this diffuse nuclear immunostain represented aggregated huntingtin was confirmed by immunohistochemistry with a polyglutamine-specific antibody, which required formic acid antigen retrieval to expose its epitope. By 6 months of age, nuclear and cytoplasmic inclusions were widely distributed throughout the brain. Homogeneous time-resolved fluorescence analysis showed that the comparative levels of soluble exon 1 huntingtin between CNS regions correlated with those for huntingtin aggregation. We found that soluble exon 1 huntingtin levels decreased over the 6-month period, whilst those of soluble full-length mutant huntingtin remained unchanged, data that were confirmed for the cortex by immunoprecipitation and western blotting. These data support the hypothesis that exon 1 huntingtin initiates the aggregation process in knock-in mouse models and pave the way for a detailed analysis of huntingtin aggregation in response to huntingtin-lowering treatments.
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Affiliation(s)
- Edward J Smith
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Kirupa Sathasivam
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Christian Landles
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Georgina F Osborne
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Michael A Mason
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Casandra Gomez-Paredes
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Bridget A Taxy
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Rebecca E Milton
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
| | - Anne Ast
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Franziska Schindler
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Chuangchuang Zhang
- Division of Neurobiology, Department Psychiatry and Behavioral Sciences; Department Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Wenzhen Duan
- Division of Neurobiology, Department Psychiatry and Behavioral Sciences; Department Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21287, USA
| | - Erich E Wanker
- Neuroproteomics, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin 13125, Germany
| | - Gillian P Bates
- Huntington’s Disease Centre, Department of Neurodegenerative Disease and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London WC1N 3BG, UK
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Fienko S, Landles C, Sathasivam K, McAteer SJ, Milton RE, Osborne GF, Smith EJ, Jones ST, Bondulich MK, Danby ECE, Phillips J, Taxy BA, Kordasiewicz HB, Bates GP. Alternative processing of human HTT mRNA with implications for Huntington's disease therapeutics. Brain 2022; 145:4409-4424. [PMID: 35793238 PMCID: PMC9762945 DOI: 10.1093/brain/awac241] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 05/17/2022] [Accepted: 06/11/2022] [Indexed: 11/14/2022] Open
Abstract
Huntington disease is caused by a CAG repeat expansion in exon 1 of the huntingtin gene (HTT) that is translated into a polyglutamine stretch in the huntingtin protein (HTT). We previously showed that HTT mRNA carrying an expanded CAG repeat was incompletely spliced to generate HTT1a, an exon 1 only transcript, which was translated to produce the highly aggregation-prone and pathogenic exon 1 HTT protein. This occurred in all knock-in mouse models of Huntington's disease and could be detected in patient cell lines and post-mortem brains. To extend these findings to a model system expressing human HTT, we took advantage of YAC128 mice that are transgenic for a yeast artificial chromosome carrying human HTT with an expanded CAG repeat. We discovered that the HTT1a transcript could be detected throughout the brains of YAC128 mice. We implemented RNAscope to visualize HTT transcripts at the single molecule level and found that full-length HTT and HTT1a were retained together in large nuclear RNA clusters, as well as being present as single transcripts in the cytoplasm. Homogeneous time-resolved fluorescence analysis demonstrated that the HTT1a transcript had been translated to produce the exon 1 HTT protein. The levels of exon 1 HTT in YAC128 mice, correlated with HTT aggregation, supportive of the hypothesis that exon 1 HTT initiates the aggregation process. Huntingtin-lowering strategies are a major focus of therapeutic development for Huntington's disease. These approaches often target full-length HTT alone and would not be expected to reduce pathogenic exon 1 HTT levels. We have established YAC128 mouse embryonic fibroblast lines and shown that, together with our QuantiGene multiplex assay, these provide an effective screening tool for agents that target HTT transcripts. The effects of current targeting strategies on nuclear RNA clusters are unknown, structures that may have a pathogenic role or alternatively could be protective by retaining HTT1a in the nucleus and preventing it from being translated. In light of recently halted antisense oligonucleotide trials, it is vital that agents targeting HTT1a are developed, and that the effects of HTT-lowering strategies on the subcellular levels of all HTT transcripts and their various HTT protein isoforms are understood.
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Affiliation(s)
- Sandra Fienko
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Christian Landles
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Kirupa Sathasivam
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Sean J McAteer
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Rebecca E Milton
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Georgina F Osborne
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Edward J Smith
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Samuel T Jones
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Marie K Bondulich
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Emily C E Danby
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Jemima Phillips
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | - Bridget A Taxy
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
| | | | - Gillian P Bates
- Department of Neurodegenerative Disease, Huntington’s Disease Centre and UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, UCL, London WC1N 3BG, UK
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Landles C, Milton RE, Jean A, McLarnon S, McAteer SJ, Taxy BA, Osborne GF, Zhang C, Duan W, Howland D, Bates GP. Development of novel bioassays to detect soluble and aggregated Huntingtin proteins on three technology platforms. Brain Commun 2021; 3:fcaa231. [PMID: 33604571 PMCID: PMC7878250 DOI: 10.1093/braincomms/fcaa231] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/27/2020] [Accepted: 12/01/2020] [Indexed: 01/29/2023] Open
Abstract
Huntington's disease is caused by a CAG / polyglutamine repeat expansion. Mutated CAG repeats undergo somatic instability, resulting in tracts of several hundred CAGs in the brain; and genetic modifiers of Huntington's disease have indicated that somatic instability is a major driver of age of onset and disease progression. As the CAG repeat expands, the likelihood that exon 1 does not splice to exon 2 increases, resulting in two transcripts that encode full-length huntingtin protein, as well as the highly pathogenic and aggregation-prone exon 1 huntingtin protein. Strategies that target the huntingtin gene or transcripts are a major focus of therapeutic development. It is essential that the levels of all isoforms of huntingtin protein can be tracked, to better understand the molecular pathogenesis, and to assess the impact of huntingtin protein-lowering approaches in preclinical studies and clinical trials. Huntingtin protein bioassays for soluble and aggregated forms of huntingtin protein are in widespread use on the homogeneous time-resolved fluorescence and Meso Scale Discovery platforms, but these do not distinguish between exon 1 huntingtin protein and full-length huntingtin protein. In addition, they are frequently used to quantify huntingtin protein levels in the context of highly expanded polyglutamine tracts, for which appropriate protein standards do not currently exist. Here, we set out to develop novel huntingtin protein bioassays to ensure that all soluble huntingtin protein isoforms could be distinguished. We utilized the zQ175 Huntington's disease mouse model that has ∼190 CAGs, a CAG repeat size for which protein standards are not available. Initially, 30 combinations of six antibodies were tested on three technology platforms: homogeneous time-resolved fluorescence, amplified luminescent proximity homogeneous assay and Meso Scale Discovery, and a triage strategy was employed to select the best assays. We found that, without a polyglutamine-length-matched standard, the vast majority of soluble mutant huntingtin protein assays cannot be used for quantitative purposes, as the highly expanded polyglutamine tract decreased assay performance. The combination of our novel assays, with those already in existence, provides a tool-kit to track: total soluble mutant huntingtin protein, soluble exon 1 huntingtin protein, soluble mutant huntingtin protein (excluding the exon 1 huntingtin protein) and total soluble full-length huntingtin protein (mutant and wild type). Several novel aggregation assays were also developed that track with disease progression. These selected assays can be used to compare the levels of huntingtin protein isoforms in a wide variety of mouse models of Huntington's disease and to determine how these change in response to genetic or therapeutic manipulations.
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Affiliation(s)
- Christian Landles
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Rebecca E Milton
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | | | | | - Sean J McAteer
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Bridget A Taxy
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Georgina F Osborne
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
| | - Chuangchuang Zhang
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wenzhen Duan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - David Howland
- CHDI Management/CHDI Foundation Inc., New York, NY, USA
| | - Gillian P Bates
- Department of Neurodegenerative Disease, Huntington’s Disease Centre, UK Dementia Research Institute at UCL, Queen Square Institute of Neurology, University College London, London, UK
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