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Vohra A, Keefe P, Puthanveetil P. Altered Metabolic Signaling and Potential Therapies in Polyglutamine Diseases. Metabolites 2024; 14:320. [PMID: 38921455 PMCID: PMC11205831 DOI: 10.3390/metabo14060320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/27/2024] [Indexed: 06/27/2024] Open
Abstract
Polyglutamine diseases comprise a cluster of genetic disorders involving neurodegeneration and movement disabilities. In polyglutamine diseases, the target proteins become aberrated due to polyglutamine repeat formation. These aberrant proteins form the root cause of associated complications. The metabolic regulation during polyglutamine diseases is not well studied and needs more attention. We have brought to light the significance of regulating glutamine metabolism during polyglutamine diseases, which could help in decreasing the neuronal damage associated with excess glutamate and nucleotide generation. Most polyglutamine diseases are accompanied by symptoms that occur due to excess glutamate and nucleotide accumulation. Along with a dysregulated glutamine metabolism, the Nicotinamide adenine dinucleotide (NAD+) levels drop down, and, under these conditions, NAD+ supplementation is the only achievable strategy. NAD+ is a major co-factor in the glutamine metabolic pathway, and it helps in maintaining neuronal homeostasis. Thus, strategies to decrease excess glutamate and nucleotide generation, as well as channelizing glutamine toward the generation of ATP and the maintenance of NAD+ homeostasis, could aid in neuronal health. Along with understanding the metabolic dysregulation that occurs during polyglutamine diseases, we have also focused on potential therapeutic strategies that could provide direct benefits or could restore metabolic homeostasis. Our review will shed light into unique metabolic causes and into ideal therapeutic strategies for treating complications associated with polyglutamine diseases.
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Affiliation(s)
- Alisha Vohra
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (A.V.); (P.K.)
| | - Patrick Keefe
- Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, IL 60515, USA; (A.V.); (P.K.)
| | - Prasanth Puthanveetil
- College of Graduate Studies, Department of Pharmacology, Midwestern University, Downers Grove, IL 60515, USA
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2
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Ciancimino C, Di Pippo M, Manco GA, Romano S, Ristori G, Scuderi G, Abdolrahimzadeh S. Multimodal Ophthalmic Imaging in Spinocerebellar Ataxia Type 7. Life (Basel) 2023; 13:2169. [PMID: 38004309 PMCID: PMC10672172 DOI: 10.3390/life13112169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/17/2023] [Accepted: 10/30/2023] [Indexed: 11/26/2023] Open
Abstract
The aim of this case series and narrative literature review is to highlight the importance of multimodal imaging in the ophthalmological examination of patients with spinocerebellar ataxia type 7 and provide a summary of the most relevant imaging techniques. Three patients with SCA7 were included in this case series. A literature review revealed twenty-one publications regarding ocular manifestations of SCA7, and the most relevant aspects are summarized. The role of different imaging techniques in the follow-up of SCA7 patients is analyzed, including color vision testing, corneal endothelial topography, color fundus photography (CFP) and autofluorescence, near infrared reflectance imaging, spectral domain optical coherence tomography (SDOCT), visual field examination, and electrophysiological tests. SDOCT provides a rapid and non-invasive imaging evaluation of disease progression over time. Additional examination including NIR imaging can provide further information on photoreceptor alteration and subtle disruption of the RPE, which are not evident with CFP at an early stage. Electrophysiological tests provide essential results on the state of cone and rod dystrophy, which could be paramount in guiding future genetic therapies. Multimodal imaging is a valuable addition to comprehensive ophthalmological examination in the diagnosis and management of patients with SCA7.
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Affiliation(s)
- Chiara Ciancimino
- Ophthalmology Unit, Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (C.C.); (M.D.P.); (G.A.M.); (S.A.)
| | - Mariachiara Di Pippo
- Ophthalmology Unit, Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (C.C.); (M.D.P.); (G.A.M.); (S.A.)
| | - Gregorio Antonio Manco
- Ophthalmology Unit, Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (C.C.); (M.D.P.); (G.A.M.); (S.A.)
| | - Silvia Romano
- Center for Experimental Neurological Therapies (CENTERS), Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (S.R.); (G.R.)
| | - Giovanni Ristori
- Center for Experimental Neurological Therapies (CENTERS), Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (S.R.); (G.R.)
- Neuroimmunology Unit, IRCCS Fondazione Santa Lucia, Via Ardeatina, 306/354, 00179 Rome, Italy
| | - Gianluca Scuderi
- Ophthalmology Unit, Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (C.C.); (M.D.P.); (G.A.M.); (S.A.)
| | - Solmaz Abdolrahimzadeh
- Ophthalmology Unit, Department of Neurosciences, Mental Health and Sensory Organs (NESMOS), St. Andrea Hospital, “Sapienza” University of Rome, Via di Grottarossa 1035/1039, 00189 Rome, Italy; (C.C.); (M.D.P.); (G.A.M.); (S.A.)
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Niewiadomska-Cimicka A, Hache A, Le Gras S, Keime C, Ye T, Eisenmann A, Harichane I, Roux MJ, Messaddeq N, Clérin E, Léveillard T, Trottier Y. Polyglutamine-expanded ATXN7 alters a specific epigenetic signature underlying photoreceptor identity gene expression in SCA7 mouse retinopathy. J Biomed Sci 2022; 29:107. [PMID: 36539812 PMCID: PMC9768914 DOI: 10.1186/s12929-022-00892-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 12/11/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Spinocerebellar ataxia type 7 (SCA7) is a neurodegenerative disorder that primarily affects the cerebellum and retina. SCA7 is caused by a polyglutamine expansion in the ATXN7 protein, a subunit of the transcriptional coactivator SAGA that acetylates histone H3 to deposit narrow H3K9ac mark at DNA regulatory elements of active genes. Defective histone acetylation has been presented as a possible cause for gene deregulation in SCA7 mouse models. However, the topography of acetylation defects at the whole genome level and its relationship to changes in gene expression remain to be determined. METHODS We performed deep RNA-sequencing and chromatin immunoprecipitation coupled to high-throughput sequencing to examine the genome-wide correlation between gene deregulation and alteration of the active transcription marks, e.g. SAGA-related H3K9ac, CBP-related H3K27ac and RNA polymerase II (RNAPII), in a SCA7 mouse retinopathy model. RESULTS Our analyses revealed that active transcription marks are reduced at most gene promoters in SCA7 retina, while a limited number of genes show changes in expression. We found that SCA7 retinopathy is caused by preferential downregulation of hundreds of highly expressed genes that define morphological and physiological identities of mature photoreceptors. We further uncovered that these photoreceptor genes harbor unusually broad H3K9ac profiles spanning the entire gene bodies and have a low RNAPII pausing. This broad H3K9ac signature co-occurs with other features that delineate superenhancers, including broad H3K27ac, binding sites for photoreceptor specific transcription factors and expression of enhancer-related non-coding RNAs (eRNAs). In SCA7 retina, downregulated photoreceptor genes show decreased H3K9 and H3K27 acetylation and eRNA expression as well as increased RNAPII pausing, suggesting that superenhancer-related features are altered. CONCLUSIONS Our study thus provides evidence that distinctive epigenetic configurations underlying high expression of cell-type specific genes are preferentially impaired in SCA7, resulting in a defect in the maintenance of identity features of mature photoreceptors. Our results also suggest that continuous SAGA-driven acetylation plays a role in preserving post-mitotic neuronal identity.
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Affiliation(s)
- Anna Niewiadomska-Cimicka
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Antoine Hache
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Stéphanie Le Gras
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Céline Keime
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Tao Ye
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Aurelie Eisenmann
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Imen Harichane
- grid.462844.80000 0001 2308 1657Department of Genetics, INSERM, CNRS, Institut de la Vision, Sorbonne University, 75012 Paris, France
| | - Michel J. Roux
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Nadia Messaddeq
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
| | - Emmanuelle Clérin
- grid.462844.80000 0001 2308 1657Department of Genetics, INSERM, CNRS, Institut de la Vision, Sorbonne University, 75012 Paris, France
| | - Thierry Léveillard
- grid.462844.80000 0001 2308 1657Department of Genetics, INSERM, CNRS, Institut de la Vision, Sorbonne University, 75012 Paris, France
| | - Yvon Trottier
- grid.11843.3f0000 0001 2157 9291Institute of Genetics and Molecular and Cellular Biology (IGBMC), INSERM U1258, CNRS UMR7104, University of Strasbourg, 67404 Illkirch, France
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Donaldson J, Powell S, Rickards N, Holmans P, Jones L. What is the Pathogenic CAG Expansion Length in Huntington's Disease? J Huntingtons Dis 2021; 10:175-202. [PMID: 33579866 PMCID: PMC7990448 DOI: 10.3233/jhd-200445] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Huntington's disease (HD) (OMIM 143100) is caused by an expanded CAG repeat tract in the HTT gene. The inherited CAG length is known to expand further in somatic and germline cells in HD subjects. Age at onset of the disease is inversely correlated with the inherited CAG length, but is further modulated by a series of genetic modifiers which are most likely to act on the CAG repeat in HTT that permit it to further expand. Longer repeats are more prone to expansions, and this expansion is age dependent and tissue-specific. Given that the inherited tract expands through life and most subjects develop disease in mid-life, this implies that in cells that degenerate, the CAG length is likely to be longer than the inherited length. These findings suggest two thresholds- the inherited CAG length which permits further expansion, and the intracellular pathogenic threshold, above which cells become dysfunctional and die. This two-step mechanism has been previously proposed and modelled mathematically to give an intracellular pathogenic threshold at a tract length of 115 CAG (95% confidence intervals 70- 165 CAG). Empirically, the intracellular pathogenic threshold is difficult to determine. Clues from studies of people and models of HD, and from other diseases caused by expanded repeat tracts, place this threshold between 60- 100 CAG, most likely towards the upper part of that range. We assess this evidence and discuss how the intracellular pathogenic threshold in manifest disease might be better determined. Knowing the cellular pathogenic threshold would be informative for both understanding the mechanism in HD and deploying treatments.
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Affiliation(s)
- Jasmine Donaldson
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Sophie Powell
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Nadia Rickards
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Peter Holmans
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
| | - Lesley Jones
- MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK
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5
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Carrillo-Rosas S, Weber C, Fievet L, Messaddeq N, Karam A, Trottier Y. Loss of zebrafish Ataxin-7, a SAGA subunit responsible for SCA7 retinopathy, causes ocular coloboma and malformation of photoreceptors. Hum Mol Genet 2020; 28:912-927. [PMID: 30445451 DOI: 10.1093/hmg/ddy401] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/31/2018] [Accepted: 11/10/2018] [Indexed: 12/26/2022] Open
Abstract
Polyglutamine (polyQ) expansion in Ataxin-7 (ATXN7) results in spinocerebellar ataxia type 7 (SCA7) and causes visual impairment. SCA7 photoreceptors progressively lose their outer segments (OSs), a structure essential for their visual function. ATXN7 is a subunit of the transcriptional coactivator Spt-Ada-Gcn5 Acetyltransferase complex, implicated in the development of the visual system in flies. To determine the function of ATXN7 in the vertebrate eye, we have inactivated ATXN7 in zebrafish. While ATXN7 depletion in flies led to gross retinal degeneration, in zebrafish, it primarily results in ocular coloboma, a structural malformation responsible for pediatric visual impairment in humans. ATXN7 inactivation leads to elevated Hedgehog signaling in the forebrain, causing an alteration of proximo-distal patterning of the optic vesicle during early eye development and coloboma. At later developmental stages, malformations of photoreceptors due to incomplete formation of their OSs are observed and correlate with altered expression of crx, a key transcription factor involved in the formation of photoreceptor OS. Therefore, we propose that a primary toxic effect of polyQ expansion is the alteration of ATXN7 function in the daily renewal of OS in SCA7. Together, our data indicate that ATXN7 plays an essential role in vertebrate eye morphogenesis and photoreceptor differentiation, and its loss of function may contribute to the development of human coloboma.
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Affiliation(s)
- Samantha Carrillo-Rosas
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
| | - Chantal Weber
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
| | - Lorraine Fievet
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
| | - Nadia Messaddeq
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
| | - Alice Karam
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
| | - Yvon Trottier
- Institute of Genetics and Molecular and Cellular Biology (IGBMC).,Centre National de la Recherche Scientifique, UMR7104.,Institut National de la Santé et de la Recherche Médicale, U1254.,University of Strasbourg, Illkirch, 67000, France
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Niewiadomska-Cimicka A, Trottier Y. Molecular Targets and Therapeutic Strategies in Spinocerebellar Ataxia Type 7. Neurotherapeutics 2019; 16:1074-1096. [PMID: 31432449 PMCID: PMC6985300 DOI: 10.1007/s13311-019-00778-5] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is a rare autosomal dominant neurodegenerative disorder characterized by progressive neuronal loss in the cerebellum, brainstem, and retina, leading to cerebellar ataxia and blindness as major symptoms. SCA7 is due to the expansion of a CAG triplet repeat that is translated into a polyglutamine tract in ATXN7. Larger SCA7 expansions are associated with earlier onset of symptoms and more severe and rapid disease progression. Here, we summarize the pathological and genetic aspects of SCA7, compile the current knowledge about ATXN7 functions, and then focus on recent advances in understanding the pathogenesis and in developing biomarkers and therapeutic strategies. ATXN7 is a bona fide subunit of the multiprotein SAGA complex, a transcriptional coactivator harboring chromatin remodeling activities, and plays a role in the differentiation of photoreceptors and Purkinje neurons, two highly vulnerable neuronal cell types in SCA7. Polyglutamine expansion in ATXN7 causes its misfolding and intranuclear accumulation, leading to changes in interactions with native partners and/or partners sequestration in insoluble nuclear inclusions. Studies of cellular and animal models of SCA7 have been crucial to unveil pathomechanistic aspects of the disease, including gene deregulation, mitochondrial and metabolic dysfunctions, cell and non-cell autonomous protein toxicity, loss of neuronal identity, and cell death mechanisms. However, a better understanding of the principal molecular mechanisms by which mutant ATXN7 elicits neurotoxicity, and how interconnected pathogenic cascades lead to neurodegeneration is needed for the development of effective therapies. At present, therapeutic strategies using nucleic acid-based molecules to silence mutant ATXN7 gene expression are under development for SCA7.
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Affiliation(s)
- Anna Niewiadomska-Cimicka
- Institute of Genetic and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR7104), Institut National de la Santé et de la Recherche Médicale (U1258), University of Strasbourg, Illkirch, France
| | - Yvon Trottier
- Institute of Genetic and Molecular and Cellular Biology (IGBMC), Centre National de la Recherche Scientifique (UMR7104), Institut National de la Santé et de la Recherche Médicale (U1258), University of Strasbourg, Illkirch, France.
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7
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Sen NE, Canet-Pons J, Halbach MV, Arsovic A, Pilatus U, Chae WH, Kaya ZE, Seidel K, Rollmann E, Mittelbronn M, Meierhofer D, De Zeeuw CI, Bosman LWJ, Gispert S, Auburger G. Generation of an Atxn2-CAG100 knock-in mouse reveals N-acetylaspartate production deficit due to early Nat8l dysregulation. Neurobiol Dis 2019; 132:104559. [PMID: 31376479 DOI: 10.1016/j.nbd.2019.104559] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/16/2019] [Accepted: 07/30/2019] [Indexed: 12/13/2022] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominant neurodegenerative disorder caused by CAG-expansion mutations in the ATXN2 gene, mainly affecting motor neurons in the spinal cord and Purkinje neurons in the cerebellum. While the large expansions were shown to cause SCA2, the intermediate length expansions lead to increased risk for several atrophic processes including amyotrophic lateral sclerosis and Parkinson variants, e.g. progressive supranuclear palsy. Intense efforts to pioneer a neuroprotective therapy for SCA2 require longitudinal monitoring of patients and identification of crucial molecular pathways. The ataxin-2 (ATXN2) protein is mainly involved in RNA translation control and regulation of nutrient metabolism during stress periods. The preferential mRNA targets of ATXN2 are yet to be determined. In order to understand the molecular disease mechanism throughout different prognostic stages, we generated an Atxn2-CAG100-knock-in (KIN) mouse model of SCA2 with intact murine ATXN2 expression regulation. Its characterization revealed somatic mosaicism of the expansion, with shortened lifespan, a progressive spatio-temporal pattern of pathology with subsequent phenotypes, and anomalies of brain metabolites such as N-acetylaspartate (NAA), all of which mirror faithfully the findings in SCA2 patients. Novel molecular analyses from stages before the onset of motor deficits revealed a strong selective effect of ATXN2 on Nat8l mRNA which encodes the enzyme responsible for NAA synthesis. This metabolite is a prominent energy store of the brain and a well-established marker for neuronal health. Overall, we present a novel authentic rodent model of SCA2, where in vivo magnetic resonance imaging was feasible to monitor progression and where the definition of earliest transcriptional abnormalities was possible. We believe that this model will not only reveal crucial insights regarding the pathomechanism of SCA2 and other ATXN2-associated disorders, but will also aid in developing gene-targeted therapies and disease prevention.
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Affiliation(s)
- Nesli-Ece Sen
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Júlia Canet-Pons
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Melanie V Halbach
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Aleksandar Arsovic
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Ulrich Pilatus
- Institute of Neuroradiology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Woon-Hyung Chae
- Georg-Speyer-Haus, Institute for Tumor Biology and Experimental Therapy, 60596 Frankfurt am Main, Germany
| | - Zeynep-Ece Kaya
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany; Department of Neurology, Cerrahpasa School of Medicine, Istanbul University, 34098 Istanbul, Turkey
| | - Kay Seidel
- Department of Anatomy II, Institute of Clinical Neuroanatomy, Goethe University, 60590 Frankfurt am Main, Germany
| | - Ewa Rollmann
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Michel Mittelbronn
- Neurological Institute (Edinger Institute), Goethe University, 60590 Frankfurt am Main, Germany; Luxembourg Centre of Neuropathology (LCNP), Luxembourg; Department of Pathology, Laboratoire National de Santé (LNS), Dudelange, Luxembourg; Luxembourg Centre for Systems Biomedicine (LCSB), University of Luxembourg, Esch-sur-Alzette, Luxembourg; Department of Oncology, NORLUX Neuro-Oncology Laboratory, Luxembourg Institute of Health (LIH), Luxembourg
| | - David Meierhofer
- Max Planck Institute for Molecular Genetics, 14195 Berlin, Germany
| | - Chris I De Zeeuw
- Netherlands Institute for Neuroscience, Royal Academy of Arts and Sciences, 1105 BA Amsterdam, the Netherlands; Department of Neuroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Laurens W J Bosman
- Department of Neuroscience, Erasmus Medical Center, 3000 CA Rotterdam, the Netherlands
| | - Suzana Gispert
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany
| | - Georg Auburger
- Experimental Neurology, Goethe University Medical School, 60590 Frankfurt am Main, Germany.
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8
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Lebon C, Behar-Cohen F, Torriglia A. Cell Death Mechanisms in a Mouse Model of Retinal Degeneration in Spinocerebellar Ataxia 7. Neuroscience 2019; 400:72-84. [PMID: 30625334 DOI: 10.1016/j.neuroscience.2018.12.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Revised: 12/30/2018] [Accepted: 12/31/2018] [Indexed: 10/27/2022]
Abstract
Spino-cerebellar ataxia type 7 (SCA7) is a polyglutamine (polyQ) disorder characterized by neurodegeneration of the brain, cerebellum, and retina caused by a polyglutamine expansion in ataxin7. The presence of an expanded polyQ tract in a mutant protein is known to induce protein aggregation, cellular stress, toxicity, and finally cell death. However, the consequences of the presence of mutant ataxin7 in the retina and the mechanisms underlying photoreceptor degeneration remain poorly understood. In this study, we show that in a retinal SCA7 mouse model, polyQ ataxin7 induces stress within the retina and activates Muller cells. Moreover, unfolded protein response and autophagy are activated in SCA7 photoreceptors. We have also shown that the photoreceptor death does not involve a caspase-dependent apoptosis but instead involves apoptosis inducing factor (AIF) and Leukocyte Elastase Inhibitor (LEI/L-DNase II). When these two cell death effectors are downregulated by their siRNA, a significant reduction in photoreceptor death is observed. These results highlight the consequences of polyQ protein expression in the retina and the role of caspase-independent pathways involved in photoreceptor cell death.
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Affiliation(s)
- Cecile Lebon
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Francine Behar-Cohen
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France
| | - Alicia Torriglia
- Inserm U1138. Centre des Recherches des Cordeliers, 15, rue de l'Ecole de Médecine, 78006 Paris, France; Université Pierre et Marie Curie, France; Université Paris Descartes, France.
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9
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Modeling Disorders of Movement. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00002-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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10
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Figiel M, Krzyzosiak WJ, Switonski PM, Szlachcic WJ. Mouse Models of SCA3 and Other Polyglutamine Repeat Ataxias. Mov Disord 2015. [DOI: 10.1016/b978-0-12-405195-9.00064-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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11
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Nonallele specific silencing of ataxin-7 improves disease phenotypes in a mouse model of SCA7. Mol Ther 2014; 22:1635-42. [PMID: 24930601 DOI: 10.1038/mt.2014.108] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Accepted: 05/07/2014] [Indexed: 11/08/2022] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is a late-onset neurodegenerative disease characterized by ataxia and vision loss with no effective treatments in the clinic. The most striking feature is the degeneration of Purkinje neurons of the cerebellum caused by the presence of polyglutamine-expanded ataxin-7. Ataxin-7 is part of a transcriptional complex, and, in the setting of mutant ataxin-7, there is misregulation of target genes. Here, we designed RNAi sequences to reduce the expression of both wildtype and mutant ataxin-7 to test if reducing ataxin-7 in Purkinje cells is both tolerated and beneficial in an animal model of SCA7. We observed sustained reduction of both wildtype and mutant ataxin-7 as well as a significant improvement of ataxia phenotypes. Furthermore, we observed a reduction in cerebellar molecular layer thinning and nuclear inclusions, a hallmark of SCA7. In addition, we observed recovery of cerebellar transcripts whose expression is disrupted in the presence of mutant ataxin-7. These data demonstrate that reduction of both wildtype and mutant ataxin-7 by RNAi is well tolerated, and contrary to what may be expected from reducing a component of the Spt-Taf9-Gcn5 acetyltransferase complex, is efficacious in the SCA7 mouse.
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Chort A, Alves S, Marinello M, Dufresnois B, Dornbierer JG, Tesson C, Latouche M, Baker DP, Barkats M, El Hachimi KH, Ruberg M, Janer A, Stevanin G, Brice A, Sittler A. Interferon beta induces clearance of mutant ataxin 7 and improves locomotion in SCA7 knock-in mice. Brain 2013; 136:1732-45. [DOI: 10.1093/brain/awt061] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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13
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Li M, Yasumura D, Ma AAK, Matthes MT, Yang H, Nielson G, Huang Y, Szoka FC, Lavail MM, Diamond MI. Intravitreal administration of HA-1077, a ROCK inhibitor, improves retinal function in a mouse model of huntington disease. PLoS One 2013; 8:e56026. [PMID: 23409115 PMCID: PMC3569418 DOI: 10.1371/journal.pone.0056026] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2012] [Accepted: 01/04/2013] [Indexed: 12/04/2022] Open
Abstract
Huntington disease (HD) is an inherited neurodegenerative disease that affects multiple brain regions. It is caused by an expanded polyglutamine tract in huntingtin (Htt). The development of therapies for HD and other neurodegenerative diseases has been hampered by multiple factors, including the lack of clear therapeutic targets, and the cost and complexity of testing lead compounds in vivo. The R6/2 HD mouse model is widely used for pre-clinical trials because of its progressive and robust neural dysfunction, which includes retinal degeneration. Profilin-1 is a Htt binding protein that inhibits Htt aggregation. Its binding to Htt is regulated by the rho-associated kinase (ROCK), which phosphorylates profilin at Ser-137. ROCK is thus a therapeutic target in HD. The ROCK inhibitor Y-27632 reduces Htt toxicity in fly and mouse models. Here we characterized the progressive retinopathy of R6/2 mice between 6–19 weeks of age to determine an optimal treatment window. We then tested a clinically approved ROCK inhibitor, HA-1077, administered intravitreally via liposome-mediated drug delivery. HA-1077 increased photopic and flicker ERG response amplitudes in R6/2 mice, but not in wild-type littermate controls. By targeting ROCK with a new inhibitor, and testing its effects in a novel in vivo model, these results validate the in vivo efficacy of a therapeutic candidate, and establish the feasibility of using the retina as a readout for CNS function in models of neurodegenerative disease.
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Affiliation(s)
- Mei Li
- Department of Neurology, Washington University in St. Louis, St. Louis, Missouri, USA
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Furrer SA, Waldherr SM, Mohanachandran MS, Baughn TD, Nguyen KT, Sopher BL, Damian VA, Garden GA, La Spada AR. Reduction of mutant ataxin-7 expression restores motor function and prevents cerebellar synaptic reorganization in a conditional mouse model of SCA7. Hum Mol Genet 2012. [PMID: 23197655 DOI: 10.1093/hmg/dds495] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is a dominantly inherited neurodegenerative disorder caused by a CAG - polyglutamine (polyQ) repeat expansion in the ataxin-7 gene. In polyQ disorders, synaptic dysfunction and neurodegeneration may develop prior to symptom onset. However, conditional expression studies of polyQ disease models demonstrate that suppression of gene expression can yield complete reversal of established behavioral abnormalities. To determine if SCA7 neurological and neurodegenerative phenotypes are reversible, we crossed PrP-floxed-SCA7-92Q BAC transgenic mice with a tamoxifen-inducible Cre recombinase transgenic line, CAGGS-Cre-ER™. PrP-floxed-SCA7-92Q BAC;CAGGS-Cre-ER™ bigenic mice were treated with a single dose of tamoxifen 1 month after the onset of detectable ataxia, which resulted in ~50% reduction of polyQ-ataxin-7 expression. Tamoxifen treatment halted or reversed SCA7 motor symptoms, reduced ataxin-7 aggregation in Purkinje cells (PCs), and prevented loss of climbing fiber (CF)-PC synapses in comparison to vehicle-treated bigenic animals and tamoxifen-treated PrP-floxed-SCA7-92Q BAC single transgenic mice. Despite this phenotype rescue, reduced ataxin-7 expression did not result in full recovery of cerebellar molecular layer thickness or prevent Bergmann glia degeneration. These results demonstrate that suppression of mutant gene expression by only 50% in a polyQ disease model can have a significant impact on disease phenotypes, even when initiated after the onset of detectable behavioral deficits. The findings reported here are consistent with the emerging view that therapies aimed at reducing neurotoxic gene expression hold the potential to halt or reverse disease progression in afflicted patients, even after the onset of neurological disability.
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Affiliation(s)
- Stephanie A Furrer
- Departments of Neurology, University of Washington, Seattle, WA 98195, USA
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15
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Figiel M, Szlachcic WJ, Switonski PM, Gabka A, Krzyzosiak WJ. Mouse models of polyglutamine diseases: review and data table. Part I. Mol Neurobiol 2012; 46:393-429. [PMID: 22956270 PMCID: PMC3461215 DOI: 10.1007/s12035-012-8315-4] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2012] [Accepted: 07/29/2012] [Indexed: 12/23/2022]
Abstract
Polyglutamine (polyQ) disorders share many similarities, such as a common mutation type in unrelated human causative genes, neurological character, and certain aspects of pathogenesis, including morphological and physiological neuronal alterations. The similarities in pathogenesis have been confirmed by findings that some experimental in vivo therapy approaches are effective in multiple models of polyQ disorders. Additionally, mouse models of polyQ diseases are often highly similar between diseases with respect to behavior and the features of the disease. The common features shared by polyQ mouse models may facilitate the investigation of polyQ disorders and may help researchers explore the mechanisms of these diseases in a broader context. To provide this context and to promote the understanding of polyQ disorders, we have collected and analyzed research data about the characterization and treatment of mouse models of polyQ diseases and organized them into two complementary Excel data tables. The data table that is presented in this review (Part I) covers the behavioral, molecular, cellular, and anatomic characteristics of polyQ mice and contains the most current knowledge about polyQ mouse models. The structure of this data table is designed in such a way that it can be filtered to allow for the immediate retrieval of the data corresponding to a single mouse model or to compare the shared and unique aspects of many polyQ models. The second data table, which is presented in another publication (Part II), covers therapeutic research in mouse models by summarizing all of the therapeutic strategies employed in the treatment of polyQ disorders, phenotypes that are used to examine the effects of the therapy, and therapeutic outcomes.
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Affiliation(s)
- Maciej Figiel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland.
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Comparative analyses of Purkinje cell gene expression profiles reveal shared molecular abnormalities in models of different polyglutamine diseases. Brain Res 2012; 1481:37-48. [PMID: 22917585 DOI: 10.1016/j.brainres.2012.08.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Revised: 08/01/2012] [Accepted: 08/01/2012] [Indexed: 01/24/2023]
Abstract
Polyglutamine (PolyQ) diseases have common features that include progressive selective neurodegeneration and the formation of protein aggregates. There is growing evidence to suggest that critical nuclear events lead to transcriptional alterations in PolyQ diseases such as spinocerebellar ataxia type 7 (SCA7) and Huntington's disease (HD), conditions which share a cerebellar degenerative phenotype. Taking advantage of laser capture microdissection technique, we compared the Purkinje cell (PC) gene expression profiles of two transgenic polyQ mouse models (HD: R6/2; SCA7: P7E) by microarray analysis that was validated by real time quantitative PCR. A large number of transcriptional alterations were detected in the R6/2 transgenic model of HD. Similar decreases in the same mRNAs, such as phospholipase C, β 3, purkinje cell protein 2 (Pcp2) and aldolase C, were found in both models. A decrease in aldolase C and phospholipase C, β 3, may lead to an increase in the vulnerability of PCs to excitotoxic events. Furthermore, downregulation of mRNAs mediated by the Pcp2-promoter is common in both models. Thus, our data reveal shared molecular abnormalities in different polyQ disorders.
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Yefimova MG, Messaddeq N, Karam A, Jacquard C, Weber C, Jonet L, Wolfrum U, Jeanny JC, Trottier Y. Polyglutamine toxicity induces rod photoreceptor division, morphological transformation or death in Spinocerebellar ataxia 7 mouse retina. Neurobiol Dis 2010; 40:311-24. [DOI: 10.1016/j.nbd.2010.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/03/2010] [Accepted: 06/11/2010] [Indexed: 12/01/2022] Open
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McCullough SD, Grant PA. Histone acetylation, acetyltransferases, and ataxia--alteration of histone acetylation and chromatin dynamics is implicated in the pathogenesis of polyglutamine-expansion disorders. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2010; 79:165-203. [PMID: 20621284 DOI: 10.1016/s1876-1623(10)79005-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Eukaryotic chromosomal DNA is packaged into nucleosomes to form a dynamic structure known as chromatin. The compaction of DNA within chromatin poses a unique hindrance with regards to the accessibility of the DNA to enzymes involved in replication, transcriptional regulation, and repair. The physical structure and physiological activity of chromatin are regulated through a diverse set of posttranslational modifications, histone exchange, and structural remodeling. Of the covalent chromatin modifications, the acetylation of lysine residues within histone proteins by acetyltransferase enzymes, such as GCN5, is one of the most prevalent and important steps in the regulation of chromatin function. Alteration of histone acetyltransferase activity can easily result in the dysregulation of gene transcription and ultimately the onset of a disease state. Many transcription factors contain polyglutamine regions within their primary sequence. Mutations resulting in the elongation of these polyglutamine tracts are associated with a disease family known as the polyglutamine expansion disorders. Spinocerebellar ataxia type 7 (SCA7) is one of the nine diseases that are grouped in this family and is caused by polyglutamine expansion of the ataxin-7 protein, which is a component of the GCN5-containing human SAGA histone acetyltransferase complex. Mutation of ataxin-7 in this manner has been shown to disrupt the structural integrity of the SAGA complex and result in aberrant chromatin acetylation patterns at the promoters of genes involved in the normal function of tissues that are affected by the disease. The specific aspects of molecular pathology are not currently understood; however, studies carried out in laboratory systems ranging from the budding yeast Saccharomyces cerevisiae to transgenic mouse models and cultured human cells are poised to allow for the elucidation of disease mechanisms and subsequent therapeutic approaches.
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Affiliation(s)
- Shaun D McCullough
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA
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Pascual-García P, Govind CK, Queralt E, Cuenca-Bono B, Llopis A, Chavez S, Hinnebusch AG, Rodríguez-Navarro S. Sus1 is recruited to coding regions and functions during transcription elongation in association with SAGA and TREX2. Genes Dev 2008; 22:2811-22. [PMID: 18923079 DOI: 10.1101/gad.483308] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Gene transcription, RNA biogenesis, and mRNA transport constitute a complicated process essential for all eukaryotic cells. The transcription/export factor Sus1 plays a key role in coupling transcription activation with mRNA export, and it resides in both the SAGA and TREX2 complexes. Moreover, Sus1 is responsible for GAL1 gene gating at the nuclear periphery, which is important for its transcriptional status. Here, we show that Sus1 is required during transcription elongation and is associated with the elongating form of RNA Polymerase II (RNAP II) phosphorylated on Ser5 and Ser2 of the C-terminal domain (CTD). In addition, Sus1 copurifies with the essential mRNA export factors Yra1 and Mex67, which bind to the mRNA cotranscriptionally. Consistently, ChIP analysis reveals that Sus1 is present at coding regions dependent on transcription in a manner stimulated by Kin28-dependent CTD phosphorylation. Strikingly, eliminating the TREX2 component Sac3 or the SAGA subunit Ubp8 partially impairs Sus1 targeting to coding sequences and upstream activating sequences (UAS). We found, unexpectedly, that Sgf73 is necessary for association of Sus1 with both SAGA and TREX2, and that its absence dramatically reduces Sus1 occupancy of UAS and ORF sequences. Our results reveal that Sus1 plays a key role in coordinating gene transcription and mRNA export by working at the interface between the SAGA and TREX2 complexes during transcription elongation.
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Uchihara T, Paulus W. Research into neurodegenerative disease: an entangled web of mice and men. Acta Neuropathol 2008; 115:1-4. [PMID: 18026966 DOI: 10.1007/s00401-007-0319-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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21
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Latouche M, Lasbleiz C, Martin E, Monnier V, Debeir T, Mouatt-Prigent A, Muriel MP, Morel L, Ruberg M, Brice A, Stevanin G, Tricoire H. A conditional pan-neuronal Drosophila model of spinocerebellar ataxia 7 with a reversible adult phenotype suitable for identifying modifier genes. J Neurosci 2007; 27:2483-92. [PMID: 17344386 PMCID: PMC6672519 DOI: 10.1523/jneurosci.5453-06.2007] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Spinocerebellar ataxia 7 (SCA7) is a neurodegenerative disease caused by a polyglutamine (polyQ) expansion in the ataxin 7 (ATXN7) protein, a member of a multiprotein complex involved in histone acetylation. We have created a conditional Drosophila model of SCA7 in which expression of truncated ATXN7 (ATXN7T) with a pathogenic polyQ expansion is induced in neurons in adult flies. In this model, mutant ATXN7T accumulated in neuronal intranuclear inclusions containing ubiquitin, the 19S proteasome subunit, and HSP70 (heat shock protein 70), as in patients. Aggregation was accompanied by a decrease in locomotion and lifespan but limited neuronal death. Disaggregation of the inclusions, when expression of expanded ATXN7T was stopped, correlated with improved locomotor function and increased lifespan, suggesting that the pathology may respond to treatment. Lifespan was then used as a quantitative marker in a candidate gene approach to validate the interest of the model and to identify generic modulators of polyQ toxicity and specific modifiers of SCA7. Several molecular pathways identified in this focused screen (proteasome function, unfolded protein stress, caspase-dependent apoptosis, and histone acetylation) were further studied in primary neuronal cultures. Sodium butyrate, a histone deacetylase inhibitor, improved the survival time of the neurons. This model is therefore a powerful tool for studying SCA7 and for the development of potential therapies for polyQ diseases.
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Affiliation(s)
- Morwena Latouche
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Christelle Lasbleiz
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Elodie Martin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Véronique Monnier
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
| | - Thomas Debeir
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Annick Mouatt-Prigent
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Marie-Paule Muriel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Lydie Morel
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
| | - Merle Ruberg
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
| | - Alexis Brice
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Giovanni Stevanin
- Institut National de la Santé et de la Recherche Médicale, Unité 679, Paris F-75013, France
- Université Pierre and Marie Curie–Paris 6, Institut Fédératif de Recherche de Neurosciences (IFR70), Unité Mixte de Recherche (UMR) S679, Group Hospitalier Pitié-Salpêtriére, Paris F-75013, France
- Assistance Publique–Hôpitaux de Paris, Groupe Hospitalier Pitié-Salpêtrière, Départment de Génétique, Cytogénétique, et Embryologie, Paris F-75013, France
| | - Hérvé Tricoire
- Centre National de la Rechereche Scientifique, UMR 7592, Insititut Jacques Monod, Campus Universitaire de Jussieu, Paris F-75251, France, and
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Merienne K, Friedman J, Akimoto M, Abou-Sleymane G, Weber C, Swaroop A, Trottier Y. Preventing polyglutamine-induced activation of c-Jun delays neuronal dysfunction in a mouse model of SCA7 retinopathy. Neurobiol Dis 2006; 25:571-81. [PMID: 17189700 PMCID: PMC1858671 DOI: 10.1016/j.nbd.2006.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2006] [Revised: 10/27/2006] [Accepted: 11/01/2006] [Indexed: 11/23/2022] Open
Abstract
We have approached the role of cellular stress in neurodegenerative diseases caused by polyglutamine expansion (polyQ) in the context of Spinocerebellar ataxia type 7 (SCA7) that includes retinal degeneration. Using the R7E mouse, in which polyQ-ataxin-7 is specifically over-expressed in rod photoreceptors, we previously showed that rod dysfunction correlated to moderate and prolonged activation of the JNK/c-Jun stress pathway. SCA7 retinopathy was also associated with reduced expression of rod-specific genes, including the transcription factor Nrl, which is essential for rod differentiation and function. Here, we report that R7E retinopathy is improved upon breeding with the JunAA knock-in mice, in which JNK-mediated activation of c-Jun is compromised. Expression of Nrl and its downstream targets, which are involved in phototranduction, are partially restored in the JunAA-R7E mice. We further show that c-Jun can directly repress the transcription of Nrl. Our studies suggest that polyQ-induced cellular stress leads to repression of genes necessary for neuronal fate and function.
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Affiliation(s)
- Karine Merienne
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - James Friedman
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Masayuki Akimoto
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- Translational Research Center, Kyoto University Hospital, Japan
| | - Gretta Abou-Sleymane
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - Chantal Weber
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
| | - Anand Swaroop
- Department of Ophthalmology & Visual Sciences, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
- Department of Human Genetics, W.K. Kellogg Eye Center, University of Michigan, Ann Arbor, MI 48105, USA
| | - Yvon Trottier
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg
- Chaire de Génétique Humaine, Collège de France
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Helmlinger D, Tora L, Devys D. [Role of chromatin alterations in neurodegeneration induced by polyglutamine-expanded ataxin-7]. Med Sci (Paris) 2006; 22:700-2. [PMID: 16962040 DOI: 10.1051/medsci/20062289700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Janer A, Martin E, Muriel MP, Latouche M, Fujigasaki H, Ruberg M, Brice A, Trottier Y, Sittler A. PML clastosomes prevent nuclear accumulation of mutant ataxin-7 and other polyglutamine proteins. ACTA ACUST UNITED AC 2006; 174:65-76. [PMID: 16818720 PMCID: PMC2064165 DOI: 10.1083/jcb.200511045] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The pathogenesis of spinocerebellar ataxia type 7 and other neurodegenerative polyglutamine (polyQ) disorders correlates with the aberrant accumulation of toxic polyQ-expanded proteins in the nucleus. Promyelocytic leukemia protein (PML) nuclear bodies are often present in polyQ aggregates, but their relation to pathogenesis is unclear. We show that expression of PML isoform IV leads to the formation of distinct nuclear bodies enriched in components of the ubiquitin-proteasome system. These bodies recruit soluble mutant ataxin-7 and promote its degradation by proteasome-dependent proteolysis, thus preventing the aggregate formation. Inversely, disruption of the endogenous nuclear bodies with cadmium increases the nuclear accumulation and aggregation of mutant ataxin-7, demonstrating their role in ataxin-7 turnover. Interestingly, β-interferon treatment, which induces the expression of endogenous PML IV, prevents the accumulation of transiently expressed mutant ataxin-7 without affecting the level of the endogenous wild-type protein. Therefore, clastosomes represent a potential therapeutic target for preventing polyQ disorders.
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Affiliation(s)
- Alexandre Janer
- Institut National de la Santé et de la Recherche Médicale U679, Neurologie et Thérapeutique Expérimentale, 75651 Paris Cedex 13, France.
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Helmlinger D, Hardy S, Abou-Sleymane G, Eberlin A, Bowman AB, Gansmüller A, Picaud S, Zoghbi HY, Trottier Y, Tora L, Devys D. Glutamine-expanded ataxin-7 alters TFTC/STAGA recruitment and chromatin structure leading to photoreceptor dysfunction. PLoS Biol 2006; 4:e67. [PMID: 16494529 PMCID: PMC1382020 DOI: 10.1371/journal.pbio.0040067] [Citation(s) in RCA: 126] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Accepted: 01/04/2006] [Indexed: 11/18/2022] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is one of several inherited neurodegenerative disorders caused by a polyglutamine (polyQ) expansion, but it is the only one in which the retina is affected. Increasing evidence suggests that transcriptional alterations contribute to polyQ pathogenesis, although the mechanism is unclear. We previously demonstrated that theSCA7 gene product, ataxin-7 (ATXN7), is a subunit of the GCN5 histone acetyltransferase–containing coactivator complexes TFTC/STAGA. We show here that TFTC/STAGA complexes purified from SCA7 mice have normal TRRAP, GCN5, TAF12, and SPT3 levels and that their histone or nucleosomal acetylation activities are unaffected. However, rod photoreceptors from SCA7 mouse models showed severe chromatin decondensation. In agreement, polyQ-expanded ataxin-7 induced histone H3 hyperacetylation, resulting from an increased recruitment of TFTC/STAGA to specific promoters. Surprisingly, hyperacetylated genes were transcriptionally down-regulated, and expression analysis revealed that nearly all rod-specific genes were affected, leading to visual impairment in SCA7 mice. In conclusion, we describe here a set of events accounting for SCA7 pathogenesis in the retina, in which polyQ-expanded ATXN7 deregulated TFTC/STAGA recruitment to a subset of genes specifically expressed in rod photoreceptors, leading to chromatin alterations and consequent progressive loss of rod photoreceptor function. A mouse model of Spinocerebellar ataxia type 7 (SCA7) offers new insight into transcriptional alterations that contribute to this neurodegenerative disorder.
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Affiliation(s)
- Dominique Helmlinger
- 1Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
| | - Sara Hardy
- 2Department of Transcription, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
| | - Gretta Abou-Sleymane
- 1Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
- 3Chaire de Génétique Humaine, Collège de France, Paris, France
| | - Adrien Eberlin
- 2Department of Transcription, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
| | - Aaron B Bowman
- 4Howard Hughes Medical Institute, Department of Molecular and Human Genetics, and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Anne Gansmüller
- 5Imaging Technology Platform, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Strasbourg, France
| | - Serge Picaud
- 6Laboratoire de Physiopathologie Cellulaire et Moléculaire de la Rétine, INSERM U-592, UPMC, Paris, France
| | - Huda Y Zoghbi
- 4Howard Hughes Medical Institute, Department of Molecular and Human Genetics, and Department of Pediatrics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Yvon Trottier
- 1Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
- 3Chaire de Génétique Humaine, Collège de France, Paris, France
| | - Làszlò Tora
- 2Department of Transcription, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
| | - Didier Devys
- 1Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
- 2Department of Transcription, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, Illkirch, France
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Abou-Sleymane G, Chalmel F, Helmlinger D, Lardenois A, Thibault C, Weber C, Mérienne K, Mandel JL, Poch O, Devys D, Trottier Y. Polyglutamine expansion causes neurodegeneration by altering the neuronal differentiation program. Hum Mol Genet 2006; 15:691-703. [PMID: 16434483 DOI: 10.1093/hmg/ddi483] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Huntington's disease (HD) and spinocerebellar ataxia type 7 (SCA7) belong to a group of inherited neurodegenerative diseases caused by polyglutamine (polyQ) expansion in corresponding proteins. Transcriptional alteration is a unifying feature of polyQ disorders; however, the relationship between polyQ-induced gene expression deregulation and degenerative processes remains unclear. R6/2 and R7E mouse models of HD and SCA7, respectively, present a comparable retinal degeneration characterized by progressive reduction of electroretinograph activity and important morphological changes of rod photoreceptors. The retina, which is a simple central nervous system tissue, allows correlating functional, morphological and molecular defects. Taking advantage of comparing polyQ-induced degeneration in two retina models, we combined gene expression profiling and molecular biology techniques to decipher the molecular pathways underlying polyQ expansion toxicity. We show that R7E and R6/2 retinal phenotype strongly correlates with loss of expression of a large cohort of genes specifically involved in phototransduction function and morphogenesis of differentiated rod photoreceptors. Accordingly, three key transcription factors (Nrl, Crx and Nr2e3) controlling rod differentiation genes, hence expression of photoreceptor specific traits, are down-regulated. Interestingly, other transcription factors known to cause inhibitory effects on photoreceptor differentiation when mis-expressed, such as Stat3, are aberrantly re-activated. Thus, our results suggest that independently from the protein context, polyQ expansion overrides the control of neuronal differentiation and maintenance, thereby causing dysfunction and degeneration.
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Affiliation(s)
- Gretta Abou-Sleymane
- Department of Molecular Pathology, Institut de Génétique et Biologie Moléculaire et Cellulaire (IGBMC), CNRS/INSERM/ULP, BP10142, 67404 Illkirch Cédex, CU de Strasbourg, France
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27
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Iijima-Ando K, Wu P, Drier EA, Iijima K, Yin JCP. cAMP-response element-binding protein and heat-shock protein 70 additively suppress polyglutamine-mediated toxicity in Drosophila. Proc Natl Acad Sci U S A 2005; 102:10261-6. [PMID: 16009936 PMCID: PMC1177387 DOI: 10.1073/pnas.0503937102] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Gene-specific expansion of polyglutamine-encoding CAG repeats can cause neurodegenerative disorders, including Huntington's disease. It is believed that part of the pathological effect of the expanded protein is due to transcriptional dysregulation. Using Drosophila as a model, we show that cAMP-response element-binding protein (CREB) is involved in expanded polyglutamine-induced toxicity. A mutation in the Drosophila homolog of CREB, dCREB2, enhances lethality due to polyglutamine peptides (polyQ), and an additional copy of dCREB2 partially rescues this lethality. Neuronal expression of expanded polyQ attenuates in vivo CRE-mediated transcription of a reporter gene. As reported previously, overexpression of heat-shock protein 70 (Hsp70) rescues polyglutamine-dependent lethality. However, it does not rescue CREB-mediated transcription. The protective effects of CREB and heat-shock protein 70 against polyQ are additive, suggesting that targeting multiple pathways may be effective for treatment of polyglutamine diseases.
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Affiliation(s)
- Kanae Iijima-Ando
- Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, NY 11724, USA.
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28
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Petrasch-Parwez E, Habbes HW, Weickert S, Löbbecke-Schumacher M, Striedinger K, Wieczorek S, Dermietzel R, Epplen JT. Fine-structural analysis and connexin expression in the retina of a transgenic model of Huntington's disease. J Comp Neurol 2004; 479:181-97. [PMID: 15452853 DOI: 10.1002/cne.20327] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Recent studies indicate that the visual system appears more frequently affected in polyglutamine diseases than expected previously. Here, we investigated retinal degenerations in adult transgenic R6/2 mice, a model for Huntington's disease (HD). Light microscopical analysis revealed retinal dystrophy all over the retina, with central areas showing major effects. Electron microscopical analysis showed strong degenerations of outer and inner photoreceptor segments, shrinkage of photoreceptor cell somata, and signs of degeneration in photoreceptor terminals in the outer plexiform layer. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling showed hints of apoptosis. Mutant huntingtin and ubiquitin were expressed in all classes of retinal neurons, the pigment epithelium, and to a minor extent in neuropil structures. For investigating possible links to functional impairments in the rod-cone pathway, expression levels of three connexins (Cx) were compared in R6/2 and wildtype mice retinae. In R6/2 mice, expression of Cx36, the major neuronal connexin in the retina, was slightly reduced in the outer plexiform layer, indicating affected photoreceptor terminals as detected at the electron microscopical level. In contrast, Cx45, a putative neuronal connexin in the retina, was remarkably reduced in the inner plexiform layer of R6/2 mice. This result corresponded to fainter signals of Cx45 mRNA as documented by in situ hybridization and to a lower level of mCx45 cDNA as obtained by polymerase chain reaction after reverse transcription, suggesting functional deficits in spatial processing of Cx45-mediated gap junction coupling due to transgene-induced retinal degenerations. Thus, it is important to clarify the meaning of visual involvement in HD.
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Affiliation(s)
- Elisabeth Petrasch-Parwez
- Department of Neuroanatomy and Molecular Brain Research, Ruhr-University Bochum, D-44780 Bochum, Germany.
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Helmlinger D, Bonnet J, Mandel JL, Trottier Y, Devys D. Hsp70 and Hsp40 chaperones do not modulate retinal phenotype in SCA7 mice. J Biol Chem 2004; 279:55969-77. [PMID: 15494410 DOI: 10.1074/jbc.m409062200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nine neurodegenerative diseases, including spinocerebellar ataxia type 7 (SCA7), are caused by the expansion of polyglutamine stretches in the respective disease-causing proteins. A hallmark of these diseases is the aggregation of expanded polyglutamine-containing proteins in nuclear inclusions that also accumulate molecular chaperones and components of the ubiquitin-proteasome system. Manipulation of HSP70 and HSP40 chaperone levels has been shown to suppress aggregates in cellular models, prevent neuronal death in Drosophila, and improve to some extent neurological symptoms in mouse models. An important issue in mammals is the relative expression levels of toxic and putative rescuing proteins. Furthermore, overexpression of both HSP70 and its co-factor HSP40/HDJ2 has never been investigated in mice. We decided to address this question in a SCA7 transgenic mouse model that progressively develops retinopathy, similar to SCA7 patients. To co-express HSP70 and HDJ2 with the polyglutamine protein, in the same cell type, at comparable levels and with the same time course, we generated transgenic mice that express the heat shock proteins specifically in rod photoreceptors. While co-expression of HSP70 with its co-factor HDJ2 efficiently suppressed mutant ataxin-7 aggregation in transfected cells, they did not prevent either neuronal toxicity or aggregate formation in SCA7 mice. Furthermore, nuclear inclusions in SCA7 mice were composed of a cleaved mutant ataxin-7 fragment, whereas they contained the full-length protein in transfected cells. We propose that differences in the aggregation process might account for the different effects of chaperone overexpression in cellular and animal models of polyglutamine diseases.
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Affiliation(s)
- Dominique Helmlinger
- Department of Molecular Pathology, Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP/Collège de France, BP 10142, 67404 Illkirch Cedex, France
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