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Aldous SG, Smith EJ, Landles C, Osborne GF, Cañibano-Pico M, Nita IM, Phillips J, Zhang Y, Jin B, Hirst MB, Benn CL, Bond BC, Edelmann W, Greene JR, Bates GP. A CAG repeat threshold for therapeutics targeting somatic instability in Huntington's disease. Brain 2024; 147:1784-1798. [PMID: 38387080 PMCID: PMC11068328 DOI: 10.1093/brain/awae063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Accepted: 02/07/2024] [Indexed: 02/24/2024] Open
Abstract
The Huntington's disease mutation is a CAG repeat expansion in the huntingtin gene that results in an expanded polyglutamine tract in the huntingtin protein. The CAG repeat is unstable and expansions of hundreds of CAGs have been detected in Huntington's disease post-mortem brains. The age of disease onset can be predicted partially from the length of the CAG repeat as measured in blood. Onset age is also determined by genetic modifiers, which in six cases involve variation in DNA mismatch repair pathways genes. Knocking-out specific mismatch repair genes in mouse models of Huntington's disease prevents somatic CAG repeat expansion. Taken together, these results have led to the hypothesis that somatic CAG repeat expansion in Huntington's disease brains is required for pathogenesis. Therefore, the pathogenic repeat threshold in brain is longer than (CAG)40, as measured in blood, and is currently unknown. The mismatch repair gene MSH3 has become a major focus for therapeutic development, as unlike other mismatch repair genes, nullizygosity for MSH3 does not cause malignancies associated with mismatch repair deficiency. Potential treatments targeting MSH3 currently under development include gene therapy, biologics and small molecules, which will be assessed for efficacy in mouse models of Huntington's disease. The zQ175 knock-in model carries a mutation of approximately (CAG)185 and develops early molecular and pathological phenotypes that have been extensively characterized. Therefore, we crossed the mutant huntingtin allele onto heterozygous and homozygous Msh3 knockout backgrounds to determine the maximum benefit of targeting Msh3 in this model. Ablation of Msh3 prevented somatic expansion throughout the brain and periphery, and reduction of Msh3 by 50% decreased the rate of expansion. This had no effect on the deposition of huntingtin aggregation in the nuclei of striatal neurons, nor on the dysregulated striatal transcriptional profile. This contrasts with ablating Msh3 in knock-in models with shorter CAG repeat expansions. Therefore, further expansion of a (CAG)185 repeat in striatal neurons does not accelerate the onset of molecular and neuropathological phenotypes. It is striking that highly expanded CAG repeats of a similar size in humans cause disease onset before 2 years of age, indicating that somatic CAG repeat expansion in the brain is not required for pathogenesis. Given that the trajectory for somatic CAG expansion in the brains of Huntington's disease mutation carriers is unknown, our study underlines the importance of administering treatments targeting somatic instability as early as possible.
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Affiliation(s)
- Sarah G Aldous
- 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
| | - 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
| | - 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
| | - Maria Cañibano-Pico
- 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
| | - Iulia M Nita
- 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
| | - Jemima Phillips
- 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
| | - Yongwei Zhang
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Bo Jin
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | | | - Caroline L Benn
- LoQus23 Therapeutics, Riverside, Babraham Research Campus, Cambridge, CB22 3AT, UK
| | - Brian C Bond
- Prism Training and Consultancy Limited, St John's Innovation Centre, Cambridge, CB4 0WS, UK
| | - Winfried Edelmann
- Department of Cell Biology, Albert Einstein College of Medicine, New York, NY 10461, USA
| | | | - 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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2
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Hicks AR, Reynolds RH, O’Callaghan B, García-Ruiz S, Gil-Martínez AL, Botía J, Plun-Favreau H, Ryten M. The non-specific lethal complex regulates genes and pathways genetically linked to Parkinson's disease. Brain 2023; 146:4974-4987. [PMID: 37522749 PMCID: PMC10689904 DOI: 10.1093/brain/awad246] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 05/12/2023] [Accepted: 06/23/2023] [Indexed: 08/01/2023] Open
Abstract
Genetic variants conferring risks for Parkinson's disease have been highlighted through genome-wide association studies, yet exploration of their specific disease mechanisms is lacking. Two Parkinson's disease candidate genes, KAT8 and KANSL1, identified through genome-wide studies and a PINK1-mitophagy screen, encode part of the histone acetylating non-specific lethal complex. This complex localizes to the nucleus, where it plays a role in transcriptional activation, and to mitochondria, where it has been suggested to have a role in mitochondrial transcription. In this study, we sought to identify whether the non-specific lethal complex has potential regulatory relationships with other genes associated with Parkinson's disease in human brain. Correlation in the expression of non-specific lethal genes and Parkinson's disease-associated genes was investigated in primary gene co-expression networks using publicly-available transcriptomic data from multiple brain regions (provided by the Genotype-Tissue Expression Consortium and UK Brain Expression Consortium), whilst secondary networks were used to examine cell type specificity. Reverse engineering of gene regulatory networks generated regulons of the complex, which were tested for heritability using stratified linkage disequilibrium score regression. Prioritized gene targets were then validated in vitro using a QuantiGene multiplex assay and publicly-available chromatin immunoprecipitation-sequencing data. Significant clustering of non-specific lethal genes was revealed alongside Parkinson's disease-associated genes in frontal cortex primary co-expression modules, amongst other brain regions. Both primary and secondary co-expression modules containing these genes were enriched for mainly neuronal cell types. Regulons of the complex contained Parkinson's disease-associated genes and were enriched for biological pathways genetically linked to disease. When examined in a neuroblastoma cell line, 41% of prioritized gene targets showed significant changes in mRNA expression following KANSL1 or KAT8 perturbation. KANSL1 and H4K8 chromatin immunoprecipitation-sequencing data demonstrated non-specific lethal complex activity at many of these genes. In conclusion, genes encoding the non-specific lethal complex are highly correlated with and regulate genes associated with Parkinson's disease. Overall, these findings reveal a potentially wider role for this protein complex in regulating genes and pathways implicated in Parkinson's disease.
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Affiliation(s)
- Amy R Hicks
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Regina H Reynolds
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, Bloomsbury, London WC1N 1EH, UK
| | - Benjamin O’Callaghan
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Sonia García-Ruiz
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, Bloomsbury, London WC1N 1EH, UK
| | - Ana Luisa Gil-Martínez
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, Bloomsbury, London WC1N 1EH, UK
- Department of Information and Communication Engineering, University of Murcia, Murcia 30100, Spain
| | - Juan Botía
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Department of Information and Communication Engineering, University of Murcia, Murcia 30100, Spain
| | - Hélène Plun-Favreau
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
| | - Mina Ryten
- Department of Neurodegenerative Disease, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK
- Aligning Science Across Parkinson’s (ASAP) Collaborative Research Network, Chevy Chase, MD 20815, USA
- Department of Genetics and Genomic Medicine, Great Ormond Street Institute of Child Health, Bloomsbury, London WC1N 1EH, UK
- NIHR GOSH Biomedical Research Centre, Great Ormond Street Institute of Child Health, Bloomsbury, London WC1N 1EH, UK
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3
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Gangwani MR, Soto JS, Jami-Alahmadi Y, Tiwari S, Kawaguchi R, Wohlschlegel JA, Khakh BS. Neuronal and astrocytic contributions to Huntington's disease dissected with zinc finger protein transcriptional repressors. Cell Rep 2023; 42:111953. [PMID: 36640336 PMCID: PMC9898160 DOI: 10.1016/j.celrep.2022.111953] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2022] [Revised: 12/15/2022] [Accepted: 12/15/2022] [Indexed: 01/09/2023] Open
Abstract
Huntington's disease (HD) is caused by expanded CAG repeats in the huntingtin gene (HTT) resulting in expression of mutant HTT proteins (mHTT) with extended polyglutamine tracts, including in striatal neurons and astrocytes. It is unknown whether pathophysiology in vivo can be attenuated by lowering mHTT in either cell type throughout the brain, and the relative contributions of neurons and astrocytes to HD remain undefined. We use zinc finger protein (ZFP) transcriptional repressors to cell-selectively lower mHTT in vivo. Astrocytes display loss of essential functions such as cholesterol metabolism that are partly driven by greater neuronal dysfunctions, which encompass neuromodulation, synaptic, and intracellular signaling pathways. Using transcriptomics, proteomics, electrophysiology, and behavior, we dissect neuronal and astrocytic contributions to HD pathophysiology. Remarkably, brain-wide delivery of neuronal ZFPs results in strong mHTT lowering, rescue of HD-associated behavioral and molecular phenotypes, and significant extension of lifespan, findings that support translational development.
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Affiliation(s)
- Mohitkumar R. Gangwani
- Department of Physiology, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - Joselyn S. Soto
- Department of Physiology, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - Yasaman Jami-Alahmadi
- Department of Biological Chemistry, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - Srushti Tiwari
- Department of Physiology, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - Riki Kawaguchi
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Human Behavior, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - James A. Wohlschlegel
- Department of Biological Chemistry, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
| | - Baljit S. Khakh
- Department of Physiology, University of California Los Angeles. Los Angeles, CA 90095-1751, USA,Department of Neurobiology, University of California Los Angeles. Los Angeles, CA 90095-1751, USA
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4
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Tauchi M, Oshita K, Urschel K, Furtmair R, Kühn C, Stumpfe FM, Botos B, Achenbach S, Dietel B. The Involvement of Cx43 in JNK1/2-Mediated Endothelial Mechanotransduction and Human Plaque Progression. Int J Mol Sci 2023; 24:ijms24021174. [PMID: 36674690 PMCID: PMC9863493 DOI: 10.3390/ijms24021174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/23/2022] [Accepted: 12/31/2022] [Indexed: 01/11/2023] Open
Abstract
Atherosclerotic lesions preferentially develop at bifurcations, characterized by non-uniform shear stress (SS). The aim of this study was to investigate SS-induced endothelial activation, focusing on stress-regulated mitogen-activated protein kinases (MAPK) and downstream signaling, and its relation to gap junction proteins, Connexins (Cxs). Human umbilical vein endothelial cells were exposed to flow ("mechanical stimulation") and stimulated with TNF-α ("inflammatory stimulation"). Phosphorylated levels of MAPKs (c-Jun N-terminal kinase (JNK1/2), extracellular signal-regulated kinase (ERK), and p38 kinase (p38K)) were quantified by flow cytometry, showing the activation of JNK1/2 and ERK. THP-1 cell adhesion under non-uniform SS was suppressed by the inhibition of JNK1/2, not of ERK. Immunofluorescence staining and quantitative real-time PCR demonstrated an induction of c-Jun and c-Fos and of Cx43 in endothelial cells by non-uniform SS, and the latter was abolished by JNK1/2 inhibition. Furthermore, plaque inflammation was analyzed in human carotid plaques (n = 40) using immunohistochemistry and quanti-gene RNA-assays, revealing elevated Cx43+ cell counts in vulnerable compared to stable plaques. Cx43+ cell burden in the plaque shoulder correlated with intraplaque neovascularization and lipid core size, while an inverse correlation was observed with fibrous cap thickness. Our results constitute the first report that JNK1/2 mediates Cx43 mechanoinduction in endothelial cells by atheroprone shear stress and that Cx43 is expressed in human carotid plaques. The correlation of Cx43+ cell counts with markers of plaque vulnerability implies its contribution to plaque progression.
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Affiliation(s)
- Miyuki Tauchi
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
- Cognitive and Molecular Research Institute of Brain Diseases, Kurume University, Kurume 830-0011, Japan
| | - Kensuke Oshita
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
- Department of Anesthesiology, School of Medicine, Kurume University, Kurume 830-0011, Japan
| | - Katharina Urschel
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Roman Furtmair
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Constanze Kühn
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Florian M. Stumpfe
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Balazs Botos
- Department of Vascular Surgery, Hospital of Nürnberg-Süd, 90471 Nürnberg, Germany
| | - Stephan Achenbach
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
| | - Barbara Dietel
- Department of Cardiology and Angiology, Erlangen University Hospital, Friedrich-Alexander University Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany
- Correspondence:
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5
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Karengera A, Bao C, Bovee TFH, Dinkla IJT, Murk AJ. A Multiplex Gene Expression Assay for Direct Measurement of RNA Transcripts in Crude Lysates of the Nematode Caenorhabditis elegans Used as a Bioanalytical Tool. ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY 2023; 42:130-142. [PMID: 36282018 PMCID: PMC10107722 DOI: 10.1002/etc.5505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 07/19/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Gene expression profiling in Caenorhabditis elegans has been demonstrated to be a potential bioanalytical tool to detect the toxic potency of environmental contaminants. The RNA transcripts of genes responding to toxic exposure can be used as biomarkers for detecting these toxins. For routine application in environmental quality monitoring, an easy-to-use multiplex assay is required to reliably quantify expression levels of these biomarkers. In the present study, a bead-based assay was developed to fingerprint gene expression in C. elegans by quantitating messenger RNAs (mRNAs) of multiple target genes directly from crude nematode lysates, circumventing RNA extraction and purification steps. The assay uses signal amplification rather than target amplification for direct measurement of toxin-induced RNA transcripts. Using a 50-gene panel, the expression changes of four candidate reference genes and 46 target mRNAs for various contaminants and wastewaters were successfully measured, and the expression profiles indicated the type of toxin present. Moreover, the multiplex assay response was in line with previous results obtained with more time-consuming reverse-transcription quantitative polymerase chain reaction and microarray analyses. In addition, the transcriptomic profiles of nematodes exposed to wastewater samples and extracts prepared from tissues of swimming crabs were evaluated. The profiles indicated the presence of organic pollutants. The present study illustrates the successful development of a multiplex fluorescent bead-based approach using nematode C. elegans crude lysates for gene expression profiling of target RNAs. This method can be used to routinely fingerprint the presence of toxic contaminants in environmental samples and to identify the most biologically active fraction of the contaminant mixture in a toxicity identification and evaluation approach. Environ Toxicol Chem 2023;42:130-142. © 2022 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.
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Affiliation(s)
- Antoine Karengera
- Department of Animal Sciences, Marine Animal Ecology GroupWageningen UniversityWageningenThe Netherlands
- Wetsus, European Centre of Excellence for Sustainable Water TechnologyLeeuwardenThe Netherlands
| | - Cong Bao
- Department of Animal Sciences, Marine Animal Ecology GroupWageningen UniversityWageningenThe Netherlands
- Department of Analysis and Testing CenterYangtze Delta Region Institute of Tsinghua UniversityJiaxingChina
| | - Toine F. H. Bovee
- Wageningen Food Safety Research, Team Bioassays & BiosensorsWageningen University & ResearchWageningenThe Netherlands
| | - Inez J. T. Dinkla
- Wetsus, European Centre of Excellence for Sustainable Water TechnologyLeeuwardenThe Netherlands
| | - Albertinka J. Murk
- Department of Animal Sciences, Marine Animal Ecology GroupWageningen UniversityWageningenThe Netherlands
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6
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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: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [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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7
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Marchionini DM, Liu JP, Ambesi-Impiombato A, Kerker K, Cirillo K, Bansal M, Mushlin R, Brunner D, Ramboz S, Kwan M, Kuhlbrodt K, Tillack K, Peters F, Rauhala L, Obenauer J, Greene JR, Hartl C, Khetarpal V, Lager B, Rosinski J, Aaronson J, Alam M, Signer E, Muñoz-Sanjuán I, Howland D, Zeitlin SO. Benefits of global mutant huntingtin lowering diminish over time in a Huntington's disease mouse model. JCI Insight 2022; 7:e161769. [PMID: 36278490 PMCID: PMC9714791 DOI: 10.1172/jci.insight.161769] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/06/2022] [Indexed: 10/02/2023] Open
Abstract
We have developed an inducible Huntington's disease (HD) mouse model that allows temporal control of whole-body allele-specific mutant huntingtin (mHtt) expression. We asked whether moderate global lowering of mHtt (~50%) was sufficient for long-term amelioration of HD-related deficits and, if so, whether early mHtt lowering (before measurable deficits) was required. Both early and late mHtt lowering delayed behavioral dysfunction and mHTT protein aggregation, as measured biochemically. However, long-term follow-up revealed that the benefits, in all mHtt-lowering groups, attenuated by 12 months of age. While early mHtt lowering attenuated cortical and striatal transcriptional dysregulation evaluated at 6 months of age, the benefits diminished by 12 months of age, and late mHtt lowering did not ameliorate striatal transcriptional dysregulation at 12 months of age. Only early mHtt lowering delayed the elevation in cerebrospinal fluid neurofilament light chain that we observed in our model starting at 9 months of age. As small-molecule HTT-lowering therapeutics progress to the clinic, our findings suggest that moderate mHtt lowering allows disease progression to continue, albeit at a slower rate, and could be relevant to the degree of mHTT lowering required to sustain long-term benefits in humans.
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Affiliation(s)
| | - Jeh-Ping Liu
- University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | | | | | | | | | | | | | | | - Mei Kwan
- Psychogenics Inc., Paramus, New Jersey, USA
| | | | | | | | | | | | | | | | | | - Brenda Lager
- CHDI Management/CHDI Foundation, New York, New York, USA
| | - Jim Rosinski
- CHDI Management/CHDI Foundation, New York, New York, USA
| | - Jeff Aaronson
- CHDI Management/CHDI Foundation, New York, New York, USA
| | - Morshed Alam
- CHDI Management/CHDI Foundation, New York, New York, USA
| | - Ethan Signer
- CHDI Management/CHDI Foundation, New York, New York, USA
| | | | - David Howland
- CHDI Management/CHDI Foundation, New York, New York, USA
| | - Scott O. Zeitlin
- University of Virginia School of Medicine, Charlottesville, Virginia, USA
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8
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Ly S, Didiot MC, Ferguson CM, Coles AH, Miller R, Chase K, Echeverria D, Wang F, Sadri-Vakili G, Aronin N, Khvorova A. Mutant huntingtin messenger RNA forms neuronal nuclear clusters in rodent and human brains. Brain Commun 2022; 4:fcac248. [PMID: 36458209 PMCID: PMC9707646 DOI: 10.1093/braincomms/fcac248] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 07/14/2022] [Accepted: 10/12/2022] [Indexed: 01/25/2023] Open
Abstract
Mutant messenger RNA (mRNA) and protein contribute to the clinical manifestation of many repeat-associated neurological disorders, with the presence of nuclear RNA clusters being a common pathological feature. Yet, investigations into Huntington's disease-caused by a CAG repeat expansion in exon 1 of the huntingtin (HTT) gene-have primarily focused on toxic protein gain-of-function as the primary disease-causing feature. To date, mutant HTT mRNA has not been identified as an in vivo hallmark of Huntington's disease. Here, we report that, in two Huntington's disease mouse models (YAC128 and BACHD-97Q-ΔN17), mutant HTT mRNA is retained in the nucleus. Widespread formation of large mRNA clusters (∼0.6-5 µm3) occurred in 50-75% of striatal and cortical neurons. Cluster formation was independent of age and driven by expanded repeats. Clusters associate with chromosomal transcriptional sites and quantitatively co-localize with the aberrantly processed N-terminal exon 1-intron 1 mRNA isoform, HTT1a. HTT1a mRNA clusters are observed in a subset of neurons from human Huntington's disease post-mortem brain and are likely caused by somatic expansion of repeats. In YAC128 mice, clusters, but not individual HTT mRNA, are resistant to antisense oligonucleotide treatment. Our findings identify mutant HTT/HTT1a mRNA clustering as an early, robust molecular signature of Huntington's disease, providing in vivo evidence that Huntington's disease is a repeat expansion disease with mRNA involvement.
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Affiliation(s)
| | | | | | - Andrew H Coles
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Rachael Miller
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Kathryn Chase
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Dimas Echeverria
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Feng Wang
- RNA Therapeutics Institute, University of Massachusetts Chan Medical School, Worcester, MA 01655, USA
| | - Ghazaleh Sadri-Vakili
- Mass General Institute for Neurodegenerative Disease, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Neil Aronin
- Correspondence may also be addressed to: Neil Aronin 368 Plantation Street, Albert Sherman Center Worcester, MA 01655, USA. E-mail:
| | - Anastasia Khvorova
- Correspondence to: Anastasia Khvorova 368 Plantation Street, Albert Sherman Center Worcester, MA 01655, USA E-mail:
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9
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Gomez-Paredes C, Mason MA, Taxy BA, Papadopoulou AS, Paganetti P, Bates GP. The heat shock response, determined by QuantiGene multiplex, is impaired in HD mouse models and not caused by HSF1 reduction. Sci Rep 2021; 11:9117. [PMID: 33907289 PMCID: PMC8079691 DOI: 10.1038/s41598-021-88715-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 04/14/2021] [Indexed: 01/09/2023] Open
Abstract
Huntington's disease (HD) is a devastating neurodegenerative disorder, caused by a CAG/polyglutamine repeat expansion, that results in the aggregation of the huntingtin protein, culminating in the deposition of inclusion bodies in HD patient brains. We have previously shown that the heat shock response becomes impaired with disease progression in mouse models of HD. The disruption of this inducible arm of the proteostasis network is likely to exacerbate the pathogenesis of this protein-folding disease. To allow a rapid and more comprehensive analysis of the heat shock response, we have developed, and validated, a 16-plex QuantiGene assay that allows the expression of Hsf1 and nine heat shock genes, to be measured directly, and simultaneously, from mouse tissue. We used this QuantiGene assay to show that, following pharmacological activation in vivo, the heat shock response impairment in tibialis anterior, brain hemispheres and striatum was comparable between zQ175 and R6/2 mice. In contrast, although a heat shock impairment could be detected in R6/2 cortex, this was not apparent in the cortex from zQ175 mice. Whilst the mechanism underlying this impairment remains unknown, our data indicated that it is not caused by a reduction in HSF1 levels, as had been reported.
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Affiliation(s)
- 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
| | - 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
| | - 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
| | - Aikaterini S Papadopoulou
- 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
| | - Paolo Paganetti
- Laboratory for Biomedical Neurosciences, Neurocenter of Southern Switzerland, Ente Ospedaliero Cantonale and Faculty of Biomedical Sciences, Università Della Svizzera Italiana, Lugano, Switzerland
| | - 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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10
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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: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [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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11
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Mason MA, Gomez-Paredes C, Sathasivam K, Neueder A, Papadopoulou AS, Bates GP. Silencing Srsf6 does not modulate incomplete splicing of the huntingtin gene in Huntington's disease models. Sci Rep 2020; 10:14057. [PMID: 32820193 PMCID: PMC7441155 DOI: 10.1038/s41598-020-71111-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 08/06/2020] [Indexed: 12/31/2022] Open
Abstract
We have previously shown that the incomplete splicing of exon 1 to exon 2 of the HTT gene results in the production of a small polyadenylated transcript (Httexon1) that encodes the highly pathogenic exon 1 HTT protein. There is evidence to suggest that the splicing factor SRSF6 is involved in the mechanism that underlies this aberrant splicing event. Therefore, we set out to test this hypothesis, by manipulating SRSF6 levels in Huntington's disease models in which an expanded CAG repeat had been knocked in to the endogenous Htt gene. We began by generating mice that were knocked out for Srsf6, and demonstrated that reduction of SRSF6 to 50% of wild type levels had no effect on incomplete splicing in zQ175 knockin mice. We found that nullizygosity for Srsf6 was embryonic lethal, and therefore, to decrease SRSF6 levels further, we established mouse embryonic fibroblasts (MEFs) from wild type, zQ175, and zQ175::Srsf6+/- mice and transfected them with an Srsf6 siRNA. The incomplete splicing of Htt was recapitulated in the MEFs and we demonstrated that ablation of SRSF6 did not modulate the levels of the Httexon1 transcript. We conclude that SRSF6 is not required for the incomplete splicing of HTT in Huntington's disease.
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Affiliation(s)
- 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
| | - 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
| | - Andreas Neueder
- Department of Neurology, Ulm University, 89081, Ulm, Germany
| | - Aikaterini-Smaragdi Papadopoulou
- 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
| | - 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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