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Wang JY, Liu YJ, Zhang XL, Liu YH, Jiang LL, Hu HY. PolyQ-expanded ataxin-2 aggregation impairs cellular processing-body homeostasis via sequestering the RNA helicase DDX6. J Biol Chem 2024; 300:107413. [PMID: 38810698 PMCID: PMC11254730 DOI: 10.1016/j.jbc.2024.107413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 04/02/2024] [Accepted: 04/10/2024] [Indexed: 05/31/2024] Open
Abstract
Ataxin-2 (Atx2) is a polyglutamine (polyQ) tract-containing RNA-binding protein, while its polyQ expansion may cause protein aggregation that is implicated in the pathogenesis of neurodegenerative diseases such as spinocerebellar ataxia type 2 (SCA2). However, the molecular mechanism underlying how Atx2 aggregation contributes to the proteinopathies remains elusive. Here, we investigated the influence of Atx2 aggregation on the assembly and functionality of cellular processing bodies (P-bodies) by using biochemical and fluorescence imaging approaches. We have revealed that polyQ-expanded (PQE) Atx2 sequesters the DEAD-box RNA helicase (DDX6), an essential component of P-bodies, into aggregates or puncta via some RNA sequences. The N-terminal like-Sm (LSm) domain of Atx2 (residues 82-184) and the C-terminal helicase domain of DDX6 are responsible for the interaction and specific sequestration. Moreover, sequestration of DDX6 may aggravate pre-mRNA mis-splicing, and interfere with the assembly of cellular P-bodies, releasing the endoribonuclease MARF1 that promotes mRNA decay and translational repression. Rescuing the DDX6 protein level can recover the assembly and functionality of P-bodies, preventing targeted mRNA from degradation. This study provides a line of evidence for sequestration of the P-body components and impairment of the P-body homeostasis in dysregulating RNA metabolism, which is implicated in the disease pathologies and a potential therapeutic target.
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Affiliation(s)
- Jian-Yang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Ya-Jun Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Xiang-Le Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Yin-Hu Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China; University of Chinese Academy of Sciences, Beijing, PR China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, PR China.
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2
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Costa RG, Conceição A, Matos CA, Nóbrega C. The polyglutamine protein ATXN2: from its molecular functions to its involvement in disease. Cell Death Dis 2024; 15:415. [PMID: 38877004 PMCID: PMC11178924 DOI: 10.1038/s41419-024-06812-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/16/2024]
Abstract
A CAG repeat sequence in the ATXN2 gene encodes a polyglutamine (polyQ) tract within the ataxin-2 (ATXN2) protein, showcasing a complex landscape of functions that have been progressively unveiled over recent decades. Despite significant progresses in the field, a comprehensive overview of the mechanisms governed by ATXN2 remains elusive. This multifaceted protein emerges as a key player in RNA metabolism, stress granules dynamics, endocytosis, calcium signaling, and the regulation of the circadian rhythm. The CAG overexpansion within the ATXN2 gene produces a protein with an extended poly(Q) tract, inducing consequential alterations in conformational dynamics which confer a toxic gain and/or partial loss of function. Although overexpanded ATXN2 is predominantly linked to spinocerebellar ataxia type 2 (SCA2), intermediate expansions are also implicated in amyotrophic lateral sclerosis (ALS) and parkinsonism. While the molecular intricacies await full elucidation, SCA2 presents ATXN2-associated pathological features, encompassing autophagy impairment, RNA-mediated toxicity, heightened oxidative stress, and disruption of calcium homeostasis. Presently, SCA2 remains incurable, with patients reliant on symptomatic and supportive treatments. In the pursuit of therapeutic solutions, various studies have explored avenues ranging from pharmacological drugs to advanced therapies, including cell or gene-based approaches. These endeavours aim to address the root causes or counteract distinct pathological features of SCA2. This review is intended to provide an updated compendium of ATXN2 functions, delineate the associated pathological mechanisms, and present current perspectives on the development of innovative therapeutic strategies.
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Affiliation(s)
- Rafael G Costa
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
| | - André Conceição
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- PhD program in Biomedical Sciences, Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
- Center for Neuroscience and Cell Biology (CNC), Coimbra, Portugal
- Champalimaud Research Program, Champalimaud Center for the Unknown, Lisbon, Portugal
| | - Carlos A Matos
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal
| | - Clévio Nóbrega
- Algarve Biomedical Center Research Institute (ABC-RI), Faro, Portugal.
- Faculdade de Medicina e Ciências Biomédicas, Universidade do Algarve (UAlg), Faro, Portugal.
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3
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Al-Chalabi A, Andrews J, Farhan S. Recent advances in the genetics of familial and sporadic ALS. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2024; 176:49-74. [PMID: 38802182 DOI: 10.1016/bs.irn.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
ALS shows complex genetic inheritance patterns. In about 5% to 10% of cases, there is a family history of ALS or a related condition such as frontotemporal dementia in a first or second degree relative, and for about 80% of such people a pathogenic gene variant can be identified. Such variants are also seen in people with no family history because of factor influencing the expression of genes, such as age. Genetic susceptibility factors also contribute to risk, and the heritability of ALS is between 40% and 60%. The genetic variants influencing ALS risk include single base changes, repeat expansions, copy number variants, and others. Here we review what is known of the genetic landscape and architecture of ALS.
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Affiliation(s)
- Ammar Al-Chalabi
- Department of Basic and Clinical Neuroscience, King's College London, London, United Kingdom.
| | - Jinsy Andrews
- Department of Neurology, Columbia University, New York, NY, United States
| | - Sali Farhan
- Department of Neurology and Neurosurgery, Montreal Neurological Institute-Hospital, Montreal, QC, Canada; Department of Human Genetics, Montreal Neurological Institute-Hospital, Montreal, QC, Canada
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4
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Liu YJ, Wang JY, Zhang XL, Jiang LL, Hu HY. Ataxin-2 sequesters Raptor into aggregates and impairs cellular mTORC1 signaling. FEBS J 2024; 291:1795-1812. [PMID: 38308810 DOI: 10.1111/febs.17081] [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: 08/02/2023] [Revised: 11/28/2023] [Accepted: 01/26/2024] [Indexed: 02/05/2024]
Abstract
Ataxin-2 (Atx2) is a polyglutamine (polyQ) protein, in which abnormal expansion of the polyQ tract can trigger protein aggregation and consequently cause spinocerebellar ataxia type 2 (SCA2), but the mechanism underlying how Atx2 aggregation leads to proteinopathy remains elusive. Here, we investigate the molecular mechanism and cellular consequences of Atx2 aggregation by molecular cell biology approaches. We have revealed that either normal or polyQ-expanded Atx2 can sequester Raptor, a component of mammalian target of rapamycin complex 1 (mTORC1), into aggregates based on their specific interaction. Further research indicates that the polyQ tract and the N-terminal region (residues 1-784) of Atx2 are responsible for the specific sequestration. Moreover, this sequestration leads to suppression of the mTORC1 activity as represented by down-regulation of phosphorylated P70S6K, which can be reversed by overexpression of Raptor. As mTORC1 is a key regulator of autophagy, Atx2 aggregation and sequestration also induces autophagy by upregulating LC3-II and reducing phosphorylated ULK1 levels. This study proposes that Atx2 sequesters Raptor into aggregates, thereby impairing cellular mTORC1 signaling and inducing autophagy, and will be beneficial for a better understanding of the pathogenesis of SCA2 and other polyQ diseases.
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Affiliation(s)
- Ya-Jun Liu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jian-Yang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xiang-Le Zhang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lei-Lei Jiang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
| | - Hong-Yu Hu
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, China
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5
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Nakayama K, Nemoto K, Arai T. Nucleus accumbens degeneration in spinocerebellar ataxia type 2: a preliminary study. Psychogeriatrics 2024; 24:345-354. [PMID: 38243757 DOI: 10.1111/psyg.13080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 12/16/2023] [Accepted: 01/06/2024] [Indexed: 01/21/2024]
Abstract
BACKGROUND Spinocerebellar ataxia type 2 (SCA2) exhibits mainly cerebellar and oculomotor dysfunctions but also, frequently, cognitive impairment and neuropsychological symptoms. The mechanism of the progression of SCA2 remains unclear. This study aimed to evaluate longitudinal structural changes in the brains of SCA2 patients based on atrophy rate. METHODS The OpenNeuro Dataset ds001378 was used. It comprises the demographic data and two magnetic resonance images each of nine SCA2 patients and 16 healthy controls. All structural images were preprocessed using FreeSurfer software, and each region's bilateral volume was summed. Atrophy rates were calculated based on the concept of symmetrised percent change and compared between SCA2 patients and healthy controls using non-parametric statistics. As post hoc analysis, correlation analysis was performed between infratentorial volume ratio and the accumbens area atrophy rates in SCA2 patients. RESULTS There were no significant differences between groups for age, gender, and the time between scans. Statistical analysis indicated a significantly larger atrophy rate of the accumbens area in SCA2 patients than in controls. Additionally, the infratentorial volume ratio and accumbens area atrophy rates showed moderate negative correlation. CONCLUSIONS This study found that nucleus accumbens (NAc) atrophy was significantly accelerated in SCA2 patients. Anatomically, the NAc is densely connected with infratentorial brain regions, so it is reasonable to posit that degeneration propagates from the cerebellum and brainstem to the NAc and other supratentorial areas. Functionally, the NAc is essential for appropriate behaviour, so NAc degeneration might contribute to neuropsychological symptoms in SCA2 patients.
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Affiliation(s)
- Kenjiro Nakayama
- Doctoral Program in Medical Sciences, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan
| | - Kiyotaka Nemoto
- Department of Psychiatry, Institute of Medicine, University of Tsukuba, Ibaraki, Japan
| | - Tetsuaki Arai
- Department of Psychiatry, Institute of Medicine, University of Tsukuba, Ibaraki, Japan
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Borrego-Hernández D, Vázquez-Costa JF, Domínguez-Rubio R, Expósito-Blázquez L, Aller E, Padró-Miquel A, García-Casanova P, Colomina MJ, Martín-Arriscado C, Osta R, Cordero-Vázquez P, Esteban-Pérez J, Povedano-Panadés M, García-Redondo A. Intermediate Repeat Expansion in the ATXN2 Gene as a Risk Factor in the ALS and FTD Spanish Population. Biomedicines 2024; 12:356. [PMID: 38397958 PMCID: PMC10886453 DOI: 10.3390/biomedicines12020356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Intermediate CAG expansions in the gene ataxin-2 (ATXN2) are a known risk factor for ALS, but little is known about their role in FTD risk. Moreover, their contribution to the risk and phenotype of patients might vary in populations with different genetic backgrounds. The aim of this study was to assess the relationship of intermediate CAG expansions in ATXN2 with the risk and phenotype of ALS and FTD in the Spanish population. Repeat-primed PCR was performed in 620 ALS and 137 FTD patients in three referral centers in Spain to determine the exact number of CAG repeats. In our cohort, ≥27 CAG repeats in ATXN2 were associated with a higher risk of developing ALS (odds ratio [OR] = 2.666 [1.471-4.882]; p = 0.0013) but not FTD (odds ratio [OR] = 1.446 [0.558-3.574]; p = 0.44). Moreover, ALS patients with ≥27 CAG repeats in ATXN2 showed a shorter survival rate compared to those with <27 repeats (hazard ratio [HR] 1.74 [1.18, 2.56], p = 0.005), more frequent limb onset (odds ratio [OR] = 2.34 [1.093-4.936]; p = 0.028) and a family history of ALS (odds ratio [OR] = 2.538 [1.375-4.634]; p = 0.002). Intermediate CAG expansions of ≥27 repeats in ATXN2 are associated with ALS risk but not with FTD in the Spanish population. ALS patients carrying an intermediate expansion in ATXN2 show more frequent limb onset but a worse prognosis than those without expansions. In patients carrying C9orf72 expansions, the intermediate ATXN2 expansion might increase the penetrance and modify the phenotype.
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Affiliation(s)
- Daniel Borrego-Hernández
- ALS Research Laboratory Unit, Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain; (L.E.-B.); (P.C.-V.); (J.E.-P.); (A.G.-R.)
| | - Juan Francisco Vázquez-Costa
- Neuromuscular Unit, ERN-NMD Group, Department of Neurology, Hospital Universitario y Politécnico La Fe, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain; (J.F.V.-C.); (P.G.-C.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain;
- Department of Medicine, University of Valencia, 46010 Valencia, Spain
| | - Raúl Domínguez-Rubio
- Motoneuron Functional Unit, Hospital Universitari de Bellvitge, 08907 L’Hospitalet de Llobregat, Spain; (R.D.-R.); (M.P.-P.)
| | - Laura Expósito-Blázquez
- ALS Research Laboratory Unit, Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain; (L.E.-B.); (P.C.-V.); (J.E.-P.); (A.G.-R.)
| | - Elena Aller
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain;
- Genetics Department, Hospital Universitario y Politécnico La Fe, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain
| | - Ariadna Padró-Miquel
- Genetics Laboratory (LCTMS), Bellvitge University Hospital-IDIBELL, 08908 L’Hospitalet de Llobregat, Spain;
| | - Pilar García-Casanova
- Neuromuscular Unit, ERN-NMD Group, Department of Neurology, Hospital Universitario y Politécnico La Fe, Instituto de Investigación Sanitaria La Fe, 46026 Valencia, Spain; (J.F.V.-C.); (P.G.-C.)
| | - María J. Colomina
- Anesthesia Service Unit, Hospital Universitari de Bellvitge, 08907 L’Hospitalet de Llobregat, Spain;
| | | | - Rosario Osta
- Laboratório de Genética e Biotecnologia (LAGENBIO), Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Aragon Institute for Health Research (IIS Aragon), Zaragoza University, 50013 Zaragoza, Spain;
| | - Pilar Cordero-Vázquez
- ALS Research Laboratory Unit, Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain; (L.E.-B.); (P.C.-V.); (J.E.-P.); (A.G.-R.)
| | - Jesús Esteban-Pérez
- ALS Research Laboratory Unit, Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain; (L.E.-B.); (P.C.-V.); (J.E.-P.); (A.G.-R.)
| | - Mónica Povedano-Panadés
- Motoneuron Functional Unit, Hospital Universitari de Bellvitge, 08907 L’Hospitalet de Llobregat, Spain; (R.D.-R.); (M.P.-P.)
| | - Alberto García-Redondo
- ALS Research Laboratory Unit, Department of Neurology, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain; (L.E.-B.); (P.C.-V.); (J.E.-P.); (A.G.-R.)
- Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), 28029 Madrid, Spain;
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Chitre M, Emery P. ATXN2 is a target of N-terminal proteolysis. PLoS One 2023; 18:e0296085. [PMID: 38128014 PMCID: PMC10735043 DOI: 10.1371/journal.pone.0296085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023] Open
Abstract
Spinocerebellar ataxia 2 (SCA2) is a neurodegenerative disorder caused by the expansion of the poly-glutamine (polyQ) tract of Ataxin-2 (ATXN2). Other polyQ-containing proteins such as ATXN7 and huntingtin are associated with the development of neurodegenerative diseases when their N-terminal polyQ domains are expanded. Furthermore, they undergo proteolytic processing events that produce N-terminal fragments that include the polyQ stretch, which are implicated in pathogenesis. Interestingly, N-terminal ATXN2 fragments were reported in a brain extract from a SCA2 patient, but it is currently unknown whether an expanded polyQ domain contributes to ATXN2 proteolytic susceptibility. Here, we used transient expression in HEK293 cells to determine whether ATXN2 is a target for specific N-terminal proteolysis. We found that ATXN2 proteins with either normal or expanded polyQ stretches undergo proteolytic cleavage releasing an N-terminal polyQ-containing fragment. We identified a short amino acid sequence downstream of the polyQ domain that is necessary for N-terminal cleavage of full-length ATXN2 and sufficient to induce proteolysis of a heterologous protein. However, this sequence is not required for cleavage of a short ATXN2 isoform produced from an alternative start codon located just upstream of the CAG repeats encoding the polyQ domain. Our study extends our understanding of ATXN2 posttranslational regulation by revealing that this protein can be the target of specific proteolytic cleavage events releasing polyQ-containing products that are modulated by the N-terminal domain of ATXN2. N-terminal ATXN2 proteolysis of expanded polyQ domains might contribute to SCA2 pathology, as observed in other neurodegenerative disorders caused by polyQ domain expansion.
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Affiliation(s)
- Monika Chitre
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
- Interdisciplinary Graduate Program, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
| | - Patrick Emery
- Department of Neurobiology, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
- Interdisciplinary Graduate Program, Morningside Graduate School of Biomedical Sciences, University of Massachusetts Chan Medical School, Worcester, Massachusetts, United States of America
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8
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Zhang S, Pei G, Li B, Li P, Lin Y. Abnormal phase separation of biomacromolecules in human diseases. Acta Biochim Biophys Sin (Shanghai) 2023; 55:1133-1152. [PMID: 37475546 PMCID: PMC10423695 DOI: 10.3724/abbs.2023139] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/07/2023] [Indexed: 07/22/2023] Open
Abstract
Membrane-less organelles (MLOs) formed through liquid-liquid phase separation (LLPS) are associated with numerous important biological functions, but the abnormal phase separation will also dysregulate the physiological processes. Emerging evidence points to the importance of LLPS in human health and diseases. Nevertheless, despite recent advancements, our knowledge of the molecular relationship between LLPS and diseases is frequently incomplete. In this review, we outline our current understanding about how aberrant LLPS affects developmental disorders, tandem repeat disorders, cancers and viral infection. We also examine disease mechanisms driven by aberrant condensates, and highlight potential treatment approaches. This study seeks to expand our understanding of LLPS by providing a valuable new paradigm for understanding phase separation and human disorders, as well as to further translate our current knowledge regarding LLPS into therapeutic discoveries.
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Affiliation(s)
- Songhao Zhang
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Gaofeng Pei
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Boya Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
| | - Pilong Li
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- Frontier Research Center for Biological StructureTsinghua UniversityBeijing100084China
| | - Yi Lin
- State Key Laboratory of Membrane BiologyTsinghua University-Peking University Joint Centre for Life SciencesSchool of Life SciencesTsinghua UniversityBeijing100084China
- IDG/McGovern Institute for Brain Research at Tsinghua UniversityBeijing100084China
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9
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Boeynaems S, Dorone Y, Zhuang Y, Shabardina V, Huang G, Marian A, Kim G, Sanyal A, Şen NE, Griffith D, Docampo R, Lasker K, Ruiz-Trillo I, Auburger G, Holehouse AS, Kabashi E, Lin Y, Gitler AD. Poly(A)-binding protein is an ataxin-2 chaperone that regulates biomolecular condensates. Mol Cell 2023; 83:2020-2034.e6. [PMID: 37295429 PMCID: PMC10318123 DOI: 10.1016/j.molcel.2023.05.025] [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: 08/23/2021] [Revised: 03/14/2023] [Accepted: 05/17/2023] [Indexed: 06/12/2023]
Abstract
Biomolecular condensation underlies the biogenesis of an expanding array of membraneless assemblies, including stress granules (SGs), which form under a variety of cellular stresses. Advances have been made in understanding the molecular grammar of a few scaffold proteins that make up these phases, but how the partitioning of hundreds of SG proteins is regulated remains largely unresolved. While investigating the rules that govern the condensation of ataxin-2, an SG protein implicated in neurodegenerative disease, we unexpectedly identified a short 14 aa sequence that acts as a condensation switch and is conserved across the eukaryote lineage. We identify poly(A)-binding proteins as unconventional RNA-dependent chaperones that control this regulatory switch. Our results uncover a hierarchy of cis and trans interactions that fine-tune ataxin-2 condensation and reveal an unexpected molecular function for ancient poly(A)-binding proteins as regulators of biomolecular condensate proteins. These findings may inspire approaches to therapeutically target aberrant phases in disease.
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Affiliation(s)
- Steven Boeynaems
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurological Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Therapeutic Innovation Center (THINC), Baylor College of Medicine, Houston, TX 77030, USA; Center for Alzheimer's and Neurodegenerative Diseases (CAND), Texas Children's Hospital, Houston, TX 77030, USA; Dan L Duncan Comprehensive Cancer Center (DLDCCC), Baylor College of Medicine, Houston, TX 77030, USA; Department of Genetics, Stanford University, Stanford, CA 94305, USA.
| | - Yanniv Dorone
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA 94305, USA; Department of Biology, Stanford University, Stanford, CA 94305, USA
| | - Yanrong Zhuang
- IDG/McGovern Institute for Brain Research, Tsinghua-Peking Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Victoria Shabardina
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, Barcelona 08003 Catalonia, Spain
| | - Guozhong Huang
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Anca Marian
- Imagine Institute, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1163, Paris Descartes Université, 75015 Paris, France
| | - Garam Kim
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Anushka Sanyal
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Nesli-Ece Şen
- Experimental Neurology, Goethe-University Hospital, 60590 Frankfurt, Germany
| | - Daniel Griffith
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Roberto Docampo
- Department of Cellular Biology and Center for Tropical and Emerging Global Diseases, University of Georgia, Athens, GA 30602, USA
| | - Keren Lasker
- The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Iñaki Ruiz-Trillo
- Institut de Biologia Evolutiva (CSIC-Universitat Pompeu Fabra), Passeig Marítim de la Barceloneta 37-49, Barcelona 08003 Catalonia, Spain; ICREA, Passeig Lluís Companys 23, Barcelona 08010 Catalonia, Spain
| | - Georg Auburger
- Experimental Neurology, Goethe-University Hospital, 60590 Frankfurt, Germany
| | - Alex S Holehouse
- Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA; Center for Biomolecular Condensates, Washington University in St Louis, St. Louis, MO 63130, USA
| | - Edor Kabashi
- Imagine Institute, Institut National de la Santé et de la Recherche Médicale (INSERM) Unité 1163, Paris Descartes Université, 75015 Paris, France
| | - Yi Lin
- IDG/McGovern Institute for Brain Research, Tsinghua-Peking Joint Centre for Life Sciences, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Aaron D Gitler
- Department of Genetics, Stanford University, Stanford, CA 94305, USA; Chan Zuckerberg Biohub, San Francisco, CA 94158, USA.
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10
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van de Poll F, Sutter BM, Acoba MG, Caballero D, Jahangiri S, Yang YS, Lee CD, Tu BP. Pbp1 associates with Puf3 and promotes translation of its target mRNAs involved in mitochondrial biogenesis. PLoS Genet 2023; 19:e1010774. [PMID: 37216416 PMCID: PMC10237644 DOI: 10.1371/journal.pgen.1010774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 06/02/2023] [Accepted: 05/07/2023] [Indexed: 05/24/2023] Open
Abstract
Pbp1 (poly(A)-binding protein-binding protein 1) is a cytoplasmic stress granule marker that is capable of forming condensates that function in the negative regulation of TORC1 signaling under respiratory conditions. Polyglutamine expansions in its mammalian ortholog ataxin-2 lead to spinocerebellar dysfunction due to toxic protein aggregation. Here, we show that loss of Pbp1 in S. cerevisiae leads to decreased amounts of mRNAs and mitochondrial proteins which are targets of Puf3, a member of the PUF (Pumilio and FBF) family of RNA-binding proteins. We found that Pbp1 supports the translation of Puf3-target mRNAs in respiratory conditions, such as those involved in the assembly of cytochrome c oxidase and subunits of mitochondrial ribosomes. We further show that Pbp1 and Puf3 interact through their respective low complexity domains, which is required for Puf3-target mRNA translation. Our findings reveal a key role for Pbp1-containing assemblies in enabling the translation of mRNAs critical for mitochondrial biogenesis and respiration. They may further explain prior associations of Pbp1/ataxin-2 with RNA, stress granule biology, mitochondrial function, and neuronal health.
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Affiliation(s)
- Floortje van de Poll
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Benjamin M. Sutter
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Michelle Grace Acoba
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Daniel Caballero
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Samira Jahangiri
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Yu-San Yang
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Chien-Der Lee
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
| | - Benjamin P. Tu
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
- Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, Texas, United States of America
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11
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TR-FRET-Based Immunoassay to Measure Ataxin-2 as a Target Engagement Marker in Spinocerebellar Ataxia Type 2. Mol Neurobiol 2023; 60:3553-3567. [PMID: 36894829 PMCID: PMC10122633 DOI: 10.1007/s12035-023-03294-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Accepted: 02/22/2023] [Indexed: 03/11/2023]
Abstract
Spinocerebellar ataxia type 2 (SCA2) is an autosomal dominantly inherited neurodegenerative disease, which belongs to the trinucleotide repeat disease group with a CAG repeat expansion in exon 1 of the ATXN2 gene resulting in an ataxin-2 protein with an expanded polyglutamine (polyQ)-stretch. The disease is late manifesting leading to early death. Today, therapeutic interventions to cure the disease or even to decelerate disease progression are not available yet. Furthermore, primary readout parameter for disease progression and therapeutic intervention studies are limited. Thus, there is an urgent need for quantifiable molecular biomarkers such as ataxin-2 becoming even more important due to numerous potential protein-lowering therapeutic intervention strategies. The aim of this study was to establish a sensitive technique to measure the amount of soluble polyQ-expanded ataxin-2 in human biofluids to evaluate ataxin-2 protein levels as prognostic and/or therapeutic biomarker in SCA2. Time-resolved fluorescence energy transfer (TR-FRET) was used to establish a polyQ-expanded ataxin-2-specific immunoassay. Two different ataxin-2 antibodies and two different polyQ-binding antibodies were validated in three different concentrations and tested in cellular and animal tissue as well as in human cell lines, comparing different buffer conditions to evaluate the best assay conditions. We established a TR-FRET-based immunoassay for soluble polyQ-expanded ataxin-2 and validated measurements in human cell lines including iPSC-derived cortical neurons. Additionally, our immunoassay was sensitive enough to monitor small ataxin-2 expression changes by siRNA or starvation treatment. We successfully established the first sensitive ataxin-2 immunoassay to measure specifically soluble polyQ-expanded ataxin-2 in human biomaterials.
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12
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Wijegunawardana D, Vishal SS, Venkatesh N, Gopal PP. Ataxin-2 polyglutamine expansions aberrantly sequester TDP-43, drive ribonucleoprotein condensate transport dysfunction and suppress local translation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.30.526372. [PMID: 36778347 PMCID: PMC9915502 DOI: 10.1101/2023.01.30.526372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Altered RNA metabolism is a common pathogenic mechanism linked to familial and sporadic Amyotrophic lateral sclerosis (ALS). ALS is characterized by mislocalization and aggregation of TDP-43, an RNA-binding protein (RBP) with multiple roles in post-transcriptional RNA processing. Recent studies have identified genetic interactions between TDP-43 and Ataxin-2, a polyglutamine (polyQ) RBP in which intermediate length polyQ expansions confer increased ALS risk. Here, we used live-cell confocal imaging, photobleaching and translation reporter assays to study the localization, transport dynamics and mRNA regulatory functions of TDP-43/Ataxin-2 in rodent primary cortical neurons. We show that Ataxin-2 polyQ expansions aberrantly sequester TDP-43 within ribonucleoprotein (RNP) condensates, and disrupt both its motility along the axon and liquid-like properties. Our data suggest that Ataxin-2 governs motility and translation of neuronal RNP condensates and that Ataxin-2 polyQ expansions fundamentally perturb spatial localization of mRNA and suppress local translation. Overall, these results indicate Ataxin-2 polyQ expansions have detrimental effects on stability, localization, and translation of transcripts critical for axonal and cytoskeletal integrity, particularly important for motor neurons.
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13
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Younger DS. Neurogenetic motor disorders. HANDBOOK OF CLINICAL NEUROLOGY 2023; 195:183-250. [PMID: 37562870 DOI: 10.1016/b978-0-323-98818-6.00003-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Advances in the field of neurogenetics have practical applications in rapid diagnosis on blood and body fluids to extract DNA, obviating the need for invasive investigations. The ability to obtain a presymptomatic diagnosis through genetic screening and biomarkers can be a guide to life-saving disease-modifying therapy or enzyme replacement therapy to compensate for the deficient disease-causing enzyme. The benefits of a comprehensive neurogenetic evaluation extend to family members in whom identification of the causal gene defect ensures carrier detection and at-risk counseling for future generations. This chapter explores the many facets of the neurogenetic evaluation in adult and pediatric motor disorders as a primer for later chapters in this volume and a roadmap for the future applications of genetics in neurology.
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Affiliation(s)
- David S Younger
- Department of Clinical Medicine and Neuroscience, CUNY School of Medicine, New York, NY, United States; Department of Medicine, Section of Internal Medicine and Neurology, White Plains Hospital, White Plains, NY, United States.
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14
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Rai S, Tapadia MG. Hsc70-4 aggravates PolyQ-mediated neurodegeneration by modulating NF-κB mediated immune response in Drosophila. Front Mol Neurosci 2022; 15:857257. [PMID: 36425218 PMCID: PMC9678916 DOI: 10.3389/fnmol.2022.857257] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 10/11/2022] [Indexed: 10/06/2023] Open
Abstract
Huntington's disease occurs when the stretch of CAG repeats in exon 1 of the huntingtin (htt) gene crosses the permissible limit, causing the mutated protein (mHtt) to form insoluble aggregates or inclusion bodies. These aggregates are non-typically associated with various essential proteins in the cells, thus disrupting cellular homeostasis. The cells try to bring back normalcy by synthesizing evolutionary conserved cellular chaperones, and Hsp70 is one of the families of heat shock proteins that has a significant part in this, which comprises of heat-inducible and cognate forms. Here, we demonstrate that the heat shock cognate (Hsc70) isoform, Hsc70-4/HSPA8, has a distinct role in polyglutamate (PolyQ)-mediated pathogenicity, and its expression is enhanced in the polyQ conditions in Drosophila. Downregulation of hsc70-4 rescues PolyQ pathogenicity with a notable improvement in the ommatidia arrangement and near-normal restoration of optic neurons leading to improvement in phototaxis response. Reduced hsc70-4 also attenuates the augmented immune response by decreasing the expression of NF-κB and the antimicrobial peptides, along with that JNK overactivation is also restored. These lead to the rescue of the photoreceptor cells, indicating a decrease in the caspase activity, thus reverting the PolyQ pathogenicity. At the molecular level, we show the interaction between Hsc70-4, Polyglutamine aggregates, and NF-κB, which may be responsible for the dysregulation of signaling molecules in polyQ conditions. Thus, the present data provides a functional link between Hsc70-4 and NF-κB under polyQ conditions.
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Affiliation(s)
| | - Madhu G. Tapadia
- Cytogenetics Laboratory, Department of Zoology, Banaras Hindu University, Varanasi, Uttar Pradesh, India
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15
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Kim G, Nakayama L, Blum JA, Akiyama T, Boeynaems S, Chakraborty M, Couthouis J, Tassoni-Tsuchida E, Rodriguez CM, Bassik MC, Gitler AD. Genome-wide CRISPR screen reveals v-ATPase as a drug target to lower levels of ALS protein ataxin-2. Cell Rep 2022; 41:111508. [PMID: 36288714 PMCID: PMC9664452 DOI: 10.1016/j.celrep.2022.111508] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 05/20/2022] [Accepted: 09/22/2022] [Indexed: 01/27/2023] Open
Abstract
Mutations in the ataxin-2 gene (ATXN2) cause the neurodegenerative disorders amyotrophic lateral sclerosis (ALS) and spinocerebellar ataxia type 2 (SCA2). A therapeutic strategy using antisense oligonucleotides targeting ATXN2 has entered clinical trial in humans. Additional ways to decrease ataxin-2 levels could lead to cheaper or less invasive therapies and elucidate how ataxin-2 is normally regulated. Here, we perform a genome-wide fluorescence-activated cell sorting (FACS)-based CRISPR-Cas9 screen in human cells and identify genes encoding components of the lysosomal vacuolar ATPase (v-ATPase) as modifiers of endogenous ataxin-2 protein levels. Multiple FDA-approved small molecule v-ATPase inhibitors lower ataxin-2 protein levels in mouse and human neurons, and oral administration of at least one of these drugs-etidronate-is sufficient to decrease ataxin-2 in the brains of mice. Together, we propose v-ATPase as a drug target for ALS and SCA2 and demonstrate the value of FACS-based screens in identifying genetic-and potentially druggable-modifiers of human disease proteins.
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Affiliation(s)
- Garam Kim
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neurosciences Interdepartmental Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Lisa Nakayama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jacob A Blum
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA; Stanford Neurosciences Interdepartmental Program, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tetsuya Akiyama
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Steven Boeynaems
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Meenakshi Chakraborty
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Julien Couthouis
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | - Caitlin M Rodriguez
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Michael C Bassik
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aaron D Gitler
- Department of Genetics, Stanford University School of Medicine, Stanford, CA 94305, USA.
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16
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Johnson SL, Tsou WL, Prifti MV, Harris AL, Todi SV. A survey of protein interactions and posttranslational modifications that influence the polyglutamine diseases. Front Mol Neurosci 2022; 15:974167. [PMID: 36187346 PMCID: PMC9515312 DOI: 10.3389/fnmol.2022.974167] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/27/2022] [Indexed: 01/20/2023] Open
Abstract
The presence and aggregation of misfolded proteins has deleterious effects in the nervous system. Among the various diseases caused by misfolded proteins is the family of the polyglutamine (polyQ) disorders. This family comprises nine members, all stemming from the same mutation—the abnormal elongation of a polyQ repeat in nine different proteins—which causes protein misfolding and aggregation, cellular dysfunction and disease. While it is the same type of mutation that causes them, each disease is distinct: it is influenced by regions and domains that surround the polyQ repeat; by proteins with which they interact; and by posttranslational modifications they receive. Here, we overview the role of non-polyQ regions that control the pathogenicity of the expanded polyQ repeat. We begin by introducing each polyQ disease, the genes affected, and the symptoms experienced by patients. Subsequently, we provide a survey of protein-protein interactions and posttranslational modifications that regulate polyQ toxicity. We conclude by discussing shared processes and pathways that bring some of the polyQ diseases together and may serve as common therapeutic entry points for this family of incurable disorders.
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Affiliation(s)
- Sean L. Johnson
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Wei-Ling Tsou
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Matthew V. Prifti
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
| | - Autumn L. Harris
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
- Maximizing Access to Research Careers (MARC) Program, Wayne State University, Detroit, MI, United States
| | - Sokol V. Todi
- Department of Pharmacology, Wayne State University, Detroit, MI, United States
- Maximizing Access to Research Careers (MARC) Program, Wayne State University, Detroit, MI, United States
- Department of Neurology, Wayne State University, Detroit, MI, United States
- *Correspondence: Sokol V. Todi,
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17
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Scoles DR, Gandelman M, Paul S, Dexheimer T, Dansithong W, Figueroa KP, Pflieger LT, Redlin S, Kales SC, Sun H, Maloney D, Damoiseaux R, Henderson MJ, Simeonov A, Jadhav A, Pulst SM. A quantitative high-throughput screen identifies compounds that lower expression of the SCA2-and ALS-associated gene ATXN2. J Biol Chem 2022; 298:102228. [PMID: 35787375 PMCID: PMC9356275 DOI: 10.1016/j.jbc.2022.102228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 06/26/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
CAG repeat expansions in the ATXN2 (ataxin-2) gene can cause the autosomal dominant disorder spinocerebellar ataxia type 2 (SCA2) as well as increase the risk of ALS. Abnormal molecular, motor, and neurophysiological phenotypes in SCA2 mouse models are normalized by lowering ATXN2 transcription, and reduction of nonmutant Atxn2 expression has been shown to increase the life span of mice overexpressing the TDP-43 (transactive response DNA-binding protein 43 kDa) ALS protein, demonstrating the potential benefits of targeting ATXN2 transcription in humans. Here, we describe a quantitative high-throughput screen to identify compounds that lower ATXN2 transcription. We screened 428,759 compounds in a multiplexed assay using an ATXN2-luciferase reporter in human embryonic kidney 293 (HEK-293) cells and identified a diverse set of compounds capable of lowering ATXN2 transcription. We observed dose-dependent reductions of endogenous ATXN2 in HEK-293 cells treated with procillaridin A, 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG), and heat shock protein 990 (HSP990), known inhibitors of HSP90 and Na+/K+-ATPases. Furthermore, HEK-293 cells expressing polyglutamine-expanded ATXN2-Q58 treated with 17-DMAG had minimally detectable ATXN2, as well as normalized markers of autophagy and endoplasmic reticulum stress, including STAU1 (Staufen 1), molecular target of rapamycin, p62, LC3-II (microtubule-associated protein 1A/1B-light chain 3II), CHOP (C/EBP homologous protein), and phospho-eIF2α (eukaryotic initiation factor 2α). Finally, bacterial artificial chromosome ATXN2-Q22 mice treated with 17-DMAG or HSP990 exhibited highly reduced ATXN2 protein abundance in the cerebellum. Taken together, our study demonstrates inhibition of HSP90 or Na+/K+-ATPases as potentially effective therapeutic strategies for treating SCA2 and ALS.
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Affiliation(s)
- Daniel R Scoles
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA.
| | - Mandi Gandelman
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Thomas Dexheimer
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | | | - Karla P Figueroa
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Lance T Pflieger
- Department of Biomedical Informatics, University of Utah, Salt Lake City, Utah, USA
| | - Scott Redlin
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Stephen C Kales
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - Hongmao Sun
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - David Maloney
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - Robert Damoiseaux
- Department of Molecular and Medical Pharmacology, Jonsson Comprehensive Cancer Center, California NanoSystems Institute, and Department of Bioengineering in the Samueli School of Engineering, University of California Los Angeles, Los Angeles, California, USA
| | - Mark J Henderson
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - Anton Simeonov
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - Ajit Jadhav
- Division of Preclinical Innovation, National Center for Advancing Translational Sciences (NCATS), Rockville, Maryland, USA
| | - Stefan M Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA.
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18
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Koyano S, Yagishita S, Tada M, Doi H, Uchihara T, Tanaka F. Parallel Appearance of Polyglutamine and Transactivation-Responsive DNA-Binding Protein 43 and Their Complementary Subcellular Localization in Brains of Patients With Spinocerebellar Ataxia Type 2. J Neuropathol Exp Neurol 2022; 81:535-544. [PMID: 35511239 DOI: 10.1093/jnen/nlac032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Spinocerebellar ataxia type 2 (SCA2) is caused by mutations in the ATXN2 gene in which toxic effects are triggered by expanded polyglutamine repeats within ataxin-2. SCA2 is accompanied by motor neuron degeneration as occurs in amyotrophic lateral sclerosis (ALS). We investigated the distribution patterns of ataxin-2 and transactivation-responsive DNA-binding protein 43 (TDP-43), a major disease-related protein in ALS, in the CNS of 3 SCA2 patients. Phosphorylated TDP-43 (pTDP-43)-positive lesions were widely distributed throughout the CNS and generally overlapped with 1C2 (expanded polyglutamine)-immunoreactive lesions. This distribution pattern is different from the pattern in limbic-predominant age-related TDP-43 encephalopathy. In SCA2, double immunostaining of TDP-43 and 1C2 in motor neurons revealed 3 staining patterns: cytoplasmic 1C2 and nuclear TDP-43, nucleocytoplasmic 1C2 and nuclear TDP-43, and nuclear 1C2 and cytoplasmic TDP-43, which reflect the early, active, and final stages of pathological change, respectively. The translocation of TDP-43 from the nucleus to the cytoplasm along with the translocation of 1C2 in the opposite direction indicates that nuclear accumulation of the disease-specific protein ataxin-2 affects the intracellular dynamics of TDP-43. Such a close interrelationship between mutant ataxin-2 and TDP-43 in the cell might account for the similarity of their distribution in the CNS of patients with SCA2.
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Affiliation(s)
- Shigeru Koyano
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.,Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Department of Neurology, Yokohama Minami Kyosai Hospital, Yokohama, Kanagawa, Japan
| | - Saburo Yagishita
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan.,Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mikiko Tada
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Hiroshi Doi
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
| | - Toshiki Uchihara
- Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan.,Neurology Clinic with Neuromorphomics Laboratory, Nitobe-Memorial Nakano General Hospital, Tokyo, Japan
| | - Fumiaki Tanaka
- Department of Neurology and Stroke Medicine, Yokohama City University Graduate School of Medicine, Yokohama, Kanagawa, Japan
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19
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Hou X, Li W, Liu P, Liu Z, Yuan Y, Ni J, Shen L, Tang B, Wang J. The Clinical and Ploynucleotide Repeat Expansion Analysis of ATXN2, NOP56, AR and C9orf72 in Patients With ALS From Mainland China. Front Neurol 2022; 13:811202. [PMID: 35599735 PMCID: PMC9120572 DOI: 10.3389/fneur.2022.811202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 04/04/2022] [Indexed: 11/13/2022] Open
Abstract
Background Repeat expansions, including those in C9orf72 and ATXN2, have been implicated in amyotrophic lateral sclerosis (ALS). However, there have been few studies on the association of AR and NOP56 repeat expansion with ALS, especially in China. Accordingly, we aimed to evaluate the frequency of C9orf72 and ATXN2 repeat mutations and investigate whether NOP56 and AR repeat expansion are risk factors for ALS. Methods In this study, 736 ALS patients and several hundred healthy controls were recruited. Polymerase chain reaction (PCR) and repeat-primed PCR (RP-PCR) were performed to determine the repeat lengths in C9orf72, ATXN2, AR, and NOP56. Results GGGGCC repeats in C9orf72 were observed in six ALS patients (0.8%, 6/736) but not in any of the controls (0/365). The patients with pathogenic GGGGCC repeats showed shorter median survival times than those with a normal genotype (p = 0.006). Regarding ATXN2 CAG repeats, we identified that intermediate repeat lengths (29–34 copies) were associated with ALS (p = 0.033), and there was no difference in clinical characteristics between the groups with and without intermediate repeats (p > 0.05). Meanwhile, we observed that there was no association between the repeat size in AR and NOP56 and ALS (p > 0.05). Conclusions Our results demonstrated that pathogenetic repeats in C9orf72 are rare in China, while intermediate CAG repeats in ATXN2 are more frequent but have no effect on disease phenotypes; the repeat size in AR and NOP56 may not be a risk factor for ALS.
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Affiliation(s)
- Xiaorong Hou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Wanzhen Li
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Pan Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Zhen Liu
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Yanchun Yuan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Jie Ni
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
| | - Lu Shen
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, China
| | - Beisha Tang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, China
| | - Junling Wang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Diseases, Xiangya Hospital, Central South University, Changsha, China
- Key Laboratory of Hunan Province in Neurodegenerative Disorders, Central South University, Changsha, China
- Laboratory of Medical Genetics, Central South University, Changsha, China
- Engineering Research Center of Hunan Province in Cognitive Impairment Disorders, Central South University, Changsha, China
- Hunan International Scientific and Technological Cooperation Base of Neurodegenerative and Neurogenetic Diseases, Changsha, China
- *Correspondence: Junling Wang
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20
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Sundberg CA, Lakk M, Paul S, Figueroa KP, Scoles DR, Pulst SM, Križaj D. The RNA-binding protein and stress granule component ATAXIN-2 is expressed in mouse and human tissues associated with glaucoma pathogenesis. J Comp Neurol 2022; 530:537-552. [PMID: 34350994 PMCID: PMC8716417 DOI: 10.1002/cne.25228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/06/2021] [Indexed: 02/03/2023]
Abstract
Polyglutamine repeat expansions in the Ataxin-2 (ATXN2) gene were first implicated in Spinocerebellar Ataxia Type 2, a disease associated with degeneration of motor neurons and Purkinje cells. Recent studies linked single nucleotide polymorphisms in the gene to elevated intraocular pressure in primary open angle glaucoma (POAG); yet, the localization of ATXN2 across glaucoma-relevant tissues of the vertebrate eye has not been thoroughly examined. This study characterizes ATXN2 expression in the mouse and human retina, and anterior eye, using an antibody validated in ATXN2-/- retinas. ATXN2-ir was localized to cytosolic sub compartments in retinal ganglion cell (RGC) somata and proximal dendrites in addition to GABAergic, glycinergic, and cholinergic amacrine cells in the inner plexiform layer (IPL) and displaced amacrine cells. Human, but not mouse retinas showed modest immunolabeling of bipolar cells. ATXN2 immunofluorescence was prominent in the trabecular meshwork and pigmented and nonpigmented cells of the ciliary body, with analyses of primary human trabecular meshwork cells confirming the finding. The expression of ATXN2 in key POAG-relevant ocular tissues supports the potential role in autophagy and stress granule formation in response to ocular hypertension.
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Affiliation(s)
- Chad A. Sundberg
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Karla P. Figueroa
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Daniel R. Scoles
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Stefan M. Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA
- Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA
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21
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Loureiro JR, Castro AF, Figueiredo AS, Silveira I. Molecular Mechanisms in Pentanucleotide Repeat Diseases. Cells 2022; 11:cells11020205. [PMID: 35053321 PMCID: PMC8773600 DOI: 10.3390/cells11020205] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 02/01/2023] Open
Abstract
The number of neurodegenerative diseases resulting from repeat expansion has increased extraordinarily in recent years. In several of these pathologies, the repeat can be transcribed in RNA from both DNA strands producing, at least, one toxic RNA repeat that causes neurodegeneration by a complex mechanism. Recently, seven diseases have been found caused by a novel intronic pentanucleotide repeat in distinct genes encoding proteins highly expressed in the cerebellum. These disorders are clinically heterogeneous being characterized by impaired motor function, resulting from ataxia or epilepsy. The role that apparently normal proteins from these mutant genes play in these pathologies is not known. However, recent advances in previously known spinocerebellar ataxias originated by abnormal non-coding pentanucleotide repeats point to a gain of a toxic function by the pathogenic repeat-containing RNA that abnormally forms nuclear foci with RNA-binding proteins. In cells, RNA foci have been shown to be formed by phase separation. Moreover, the field of repeat expansions has lately achieved an extraordinary progress with the discovery that RNA repeats, polyglutamine, and polyalanine proteins are crucial for the formation of nuclear membraneless organelles by phase separation, which is perturbed when they are expanded. This review will cover the amazing advances on repeat diseases.
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Affiliation(s)
- Joana R. Loureiro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F. Castro
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Ana S. Figueiredo
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, 4050-313 Porto, Portugal
| | - Isabel Silveira
- Genetics of Cognitive Dysfunction Laboratory, i3S- Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (J.R.L.); (A.F.C.); (A.S.F.)
- Institute for Molecular and Cell Biology, Universidade do Porto, 4200-135 Porto, Portugal
- Correspondence: ; Tel.: +351-2240-8800
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22
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Rounds JC, Corgiat EB, Ye C, Behnke JA, Kelly SM, Corbett AH, Moberg KH. The disease-associated proteins Drosophila Nab2 and Ataxin-2 interact with shared RNAs and coregulate neuronal morphology. Genetics 2022; 220:iyab175. [PMID: 34791182 PMCID: PMC8733473 DOI: 10.1093/genetics/iyab175] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 09/27/2021] [Indexed: 01/05/2023] Open
Abstract
Nab2 encodes the Drosophila melanogaster member of a conserved family of zinc finger polyadenosine RNA-binding proteins (RBPs) linked to multiple steps in post-transcriptional regulation. Mutation of the Nab2 human ortholog ZC3H14 gives rise to an autosomal recessive intellectual disability but understanding of Nab2/ZC3H14 function in metazoan nervous systems is limited, in part because no comprehensive identification of metazoan Nab2/ZC3H14-associated RNA transcripts has yet been conducted. Moreover, many Nab2/ZC3H14 functional protein partnerships remain unidentified. Here, we present evidence that Nab2 genetically interacts with Ataxin-2 (Atx2), which encodes a neuronal translational regulator, and that these factors coordinately regulate neuronal morphology, circadian behavior, and adult viability. We then present the first high-throughput identifications of Nab2- and Atx2-associated RNAs in Drosophila brain neurons using RNA immunoprecipitation-sequencing (RIP-Seq). Critically, the RNA interactomes of each RBP overlap, and Nab2 exhibits high specificity in its RNA associations in neurons in vivo, associating with a small fraction of all polyadenylated RNAs. The identities of shared associated transcripts (e.g., drk, me31B, stai) and of transcripts specific to Nab2 or Atx2 (e.g., Arpc2 and tea) promise insight into neuronal functions of, and genetic interactions between, each RBP. Consistent with prior biochemical studies, Nab2-associated neuronal RNAs are overrepresented for internal A-rich motifs, suggesting these sequences may partially mediate Nab2 target selection. These data support a model where Nab2 functionally opposes Atx2 in neurons, demonstrate Nab2 shares associated neuronal RNAs with Atx2, and reveal Drosophila Nab2 associates with a more specific subset of polyadenylated mRNAs than its polyadenosine affinity alone may suggest.
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Affiliation(s)
- J Christopher Rounds
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Edwin B Corgiat
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Changtian Ye
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Joseph A Behnke
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Seth M Kelly
- Department of Biology, The College of Wooster, Wooster, OH 44691, USA
| | - Anita H Corbett
- Department of Biology, Emory University, Atlanta, GA 30322, USA
| | - Kenneth H Moberg
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA
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23
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Jablonka S, Hennlein L, Sendtner M. Therapy development for spinal muscular atrophy: perspectives for muscular dystrophies and neurodegenerative disorders. Neurol Res Pract 2022; 4:2. [PMID: 34983696 PMCID: PMC8725368 DOI: 10.1186/s42466-021-00162-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/21/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Major efforts have been made in the last decade to develop and improve therapies for proximal spinal muscular atrophy (SMA). The introduction of Nusinersen/Spinraza™ as an antisense oligonucleotide therapy, Onasemnogene abeparvovec/Zolgensma™ as an AAV9-based gene therapy and Risdiplam/Evrysdi™ as a small molecule modifier of pre-mRNA splicing have set new standards for interference with neurodegeneration. MAIN BODY Therapies for SMA are designed to interfere with the cellular basis of the disease by modifying pre-mRNA splicing and enhancing expression of the Survival Motor Neuron (SMN) protein, which is only expressed at low levels in this disorder. The corresponding strategies also can be applied to other disease mechanisms caused by loss of function or toxic gain of function mutations. The development of therapies for SMA was based on the use of cell culture systems and mouse models, as well as innovative clinical trials that included readouts that had originally been introduced and optimized in preclinical studies. This is summarized in the first part of this review. The second part discusses current developments and perspectives for amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease, as well as the obstacles that need to be overcome to introduce RNA-based therapies and gene therapies for these disorders. CONCLUSION RNA-based therapies offer chances for therapy development of complex neurodegenerative disorders such as amyotrophic lateral sclerosis, muscular dystrophies, Parkinson's and Alzheimer's disease. The experiences made with these new drugs for SMA, and also the experiences in AAV gene therapies could help to broaden the spectrum of current approaches to interfere with pathophysiological mechanisms in neurodegeneration.
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Affiliation(s)
- Sibylle Jablonka
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
| | - Luisa Hennlein
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany
| | - Michael Sendtner
- Institute of Clinical Neurobiology, University Hospital of Wuerzburg, Versbacher Str. 5, 97078, Wuerzburg, Germany.
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24
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Gall-Duncan T, Sato N, Yuen RKC, Pearson CE. Advancing genomic technologies and clinical awareness accelerates discovery of disease-associated tandem repeat sequences. Genome Res 2022; 32:1-27. [PMID: 34965938 PMCID: PMC8744678 DOI: 10.1101/gr.269530.120] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Accepted: 11/29/2021] [Indexed: 11/25/2022]
Abstract
Expansions of gene-specific DNA tandem repeats (TRs), first described in 1991 as a disease-causing mutation in humans, are now known to cause >60 phenotypes, not just disease, and not only in humans. TRs are a common form of genetic variation with biological consequences, observed, so far, in humans, dogs, plants, oysters, and yeast. Repeat diseases show atypical clinical features, genetic anticipation, and multiple and partially penetrant phenotypes among family members. Discovery of disease-causing repeat expansion loci accelerated through technological advances in DNA sequencing and computational analyses. Between 2019 and 2021, 17 new disease-causing TR expansions were reported, totaling 63 TR loci (>69 diseases), with a likelihood of more discoveries, and in more organisms. Recent and historical lessons reveal that properly assessed clinical presentations, coupled with genetic and biological awareness, can guide discovery of disease-causing unstable TRs. We highlight critical but underrecognized aspects of TR mutations. Repeat motifs may not be present in current reference genomes but will be in forthcoming gapless long-read references. Repeat motif size can be a single nucleotide to kilobases/unit. At a given locus, repeat motif sequence purity can vary with consequence. Pathogenic repeats can be "insertions" within nonpathogenic TRs. Expansions, contractions, and somatic length variations of TRs can have clinical/biological consequences. TR instabilities occur in humans and other organisms. TRs can be epigenetically modified and/or chromosomal fragile sites. We discuss the expanding field of disease-associated TR instabilities, highlighting prospects, clinical and genetic clues, tools, and challenges for further discoveries of disease-causing TR instabilities and understanding their biological and pathological impacts-a vista that is about to expand.
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Affiliation(s)
- Terence Gall-Duncan
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Nozomu Sato
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
| | - Ryan K C Yuen
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - Christopher E Pearson
- Program of Genetics and Genome Biology, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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25
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Molecular and Clinical Implications of Variant Repeats in Myotonic Dystrophy Type 1. Int J Mol Sci 2021; 23:ijms23010354. [PMID: 35008780 PMCID: PMC8745394 DOI: 10.3390/ijms23010354] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/14/2021] [Accepted: 12/18/2021] [Indexed: 12/13/2022] Open
Abstract
Myotonic dystrophy type 1 (DM1) is one of the most variable monogenic diseases at phenotypic, genetic, and epigenetic level. The disease is multi-systemic with the age at onset ranging from birth to late age. The underlying mutation is an unstable expansion of CTG repeats in the DMPK gene, varying in size from 50 to >1000 repeats. Generally, large expansions are associated with an earlier age at onset. Additionally, the most severe, congenital DM1 form is typically associated with local DNA methylation. Genetic variability of DM1 mutation is further increased by its structural variations due to presence of other repeats (e.g., CCG, CTC, CAG). These variant repeats or repeat interruptions seem to confer an additional level of epigenetic variability since local DNA methylation is frequently associated with variant CCG repeats independently of the expansion size. The effect of repeat interruptions on DM1 molecular pathogenesis is not investigated enough. Studies on patients indicate their stabilizing effect on DMPK expansions because no congenital cases were described in patients with repeat interruptions, and the age at onset is frequently later than expected. Here, we review the clinical relevance of repeat interruptions in DM1 and genetic and epigenetic characteristics of interrupted DMPK expansions based on patient studies.
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26
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Skariah G, Albin RL. Repeat RNA Toxicity Drives Ribosomal RNA Processing Defects in SCA2. Mov Disord 2021; 36:2464-2467. [PMID: 34783387 DOI: 10.1002/mds.28795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 11/05/2022] Open
Affiliation(s)
- Geena Skariah
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - Roger Lee Albin
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA.,Neurology Service and GRECC, VAAAHS, Ann Arbor, Michigan, USA
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27
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Perez BA, Shorrock HK, Banez‐Coronel M, Zu T, Romano LEL, Laboissonniere LA, Reid T, Ikeda Y, Reddy K, Gomez CM, Bird T, Ashizawa T, Schut LJ, Brusco A, Berglund JA, Hasholt LF, Nielsen JE, Subramony SH, Ranum LPW. CCG•CGG interruptions in high-penetrance SCA8 families increase RAN translation and protein toxicity. EMBO Mol Med 2021; 13:e14095. [PMID: 34632710 PMCID: PMC8573593 DOI: 10.15252/emmm.202114095] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 09/09/2021] [Accepted: 09/10/2021] [Indexed: 12/28/2022] Open
Abstract
Spinocerebellar ataxia type 8 (SCA8), a dominantly inherited neurodegenerative disorder caused by a CTG•CAG expansion, is unusual because most individuals that carry the mutation do not develop ataxia. To understand the variable penetrance of SCA8, we studied the molecular differences between highly penetrant families and more common sporadic cases (82%) using a large cohort of SCA8 families (n = 77). We show that repeat expansion mutations from individuals with multiple affected family members have CCG•CGG interruptions at a higher frequency than sporadic SCA8 cases and that the number of CCG•CGG interruptions correlates with age at onset. At the molecular level, CCG•CGG interruptions increase RNA hairpin stability, and in cell culture experiments, increase p-eIF2α and polyAla and polySer RAN protein levels. Additionally, CCG•CGG interruptions, which encode arginine interruptions in the polyGln frame, increase toxicity of the resulting proteins. In summary, SCA8 CCG•CGG interruptions increase polyAla and polySer RAN protein levels, polyGln protein toxicity, and disease penetrance and provide novel insight into the molecular differences between SCA8 families with high vs. low disease penetrance.
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Affiliation(s)
- Barbara A Perez
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Hannah K Shorrock
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Monica Banez‐Coronel
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Tao Zu
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Lisa EL Romano
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Lauren A Laboissonniere
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Tammy Reid
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
| | - Yoshio Ikeda
- Department of NeurologyGunma UniversityMaebashiJapan
| | - Kaalak Reddy
- RNA InstituteUniversity at Albany–SUNYAlbanyNYUSA
| | | | - Thomas Bird
- Department of NeurologyUniversity of WashingtonSeattleWAUSA
- Geriatrics Research SectionVA Puget Sound Health Care SystemSeattleWAUSA
| | - Tetsuo Ashizawa
- Department of NeurologyHouston Methodist Research InstituteHoustonTXUSA
| | | | - Alfredo Brusco
- Department of Medical SciencesUniversity of TorinoTorinoItaly
- Medical Genetics Units“Città della Salute e della Scienza” University HospitalTorinoItaly
| | - J Andrew Berglund
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- RNA InstituteUniversity at Albany–SUNYAlbanyNYUSA
| | - Lis F Hasholt
- Institute of Cellular and Molecular MedicineUniversity of CopenhagenCopenhagenDenmark
| | - Jorgen E Nielsen
- Department of NeurologyRigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - SH Subramony
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- McKnight Brain InstituteUniversity of FloridaGainesvilleFLUSA
| | - Laura PW Ranum
- Center for NeuroGeneticsUniversity of FloridaGainesvilleFLUSA
- Department of Molecular Genetics and MicrobiologyUniversity of FloridaGainesvilleFLUSA
- McKnight Brain InstituteUniversity of FloridaGainesvilleFLUSA
- Genetics InstituteUniversity of FloridaGainesvilleFLUSA
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28
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Laneve P, Tollis P, Caffarelli E. RNA Deregulation in Amyotrophic Lateral Sclerosis: The Noncoding Perspective. Int J Mol Sci 2021; 22:10285. [PMID: 34638636 PMCID: PMC8508793 DOI: 10.3390/ijms221910285] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/17/2021] [Accepted: 09/22/2021] [Indexed: 12/18/2022] Open
Abstract
RNA metabolism is central to cellular physiopathology. Almost all the molecular pathways underpinning biological processes are affected by the events governing the RNA life cycle, ranging from transcription to degradation. The deregulation of these processes contributes to the onset and progression of human diseases. In recent decades, considerable efforts have been devoted to the characterization of noncoding RNAs (ncRNAs) and to the study of their role in the homeostasis of the nervous system (NS), where they are highly enriched. Acting as major regulators of gene expression, ncRNAs orchestrate all the steps of the differentiation programs, participate in the mechanisms underlying neural functions, and are crucially implicated in the development of neuronal pathologies, among which are neurodegenerative diseases. This review aims to explore the link between ncRNA dysregulation and amyotrophic lateral sclerosis (ALS), the most frequent motoneuron (MN) disorder in adults. Notably, defective RNA metabolism is known to be largely associated with this pathology, which is often regarded as an RNA disease. We also discuss the potential role that these transcripts may play as diagnostic biomarkers and therapeutic targets.
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Affiliation(s)
- Pietro Laneve
- Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy
| | - Paolo Tollis
- Department of Biology and Biotechnology Charles Darwin, Sapienza University of Rome, 00185 Rome, Italy;
| | - Elisa Caffarelli
- Institute of Molecular Biology and Pathology, National Research Council, 00185 Rome, Italy
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29
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McGurk L, Rifai OM, Shcherbakova O, Perlegos AE, Byrns CN, Carranza FR, Zhou HW, Kim HJ, Zhu Y, Bonini NM. Toxicity of pathogenic ataxin-2 in Drosophila shows dependence on a pure CAG repeat sequence. Hum Mol Genet 2021; 30:1797-1810. [PMID: 34077532 PMCID: PMC8444453 DOI: 10.1093/hmg/ddab148] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 12/31/2022] Open
Abstract
Spinocerebellar ataxia type 2 is a polyglutamine (polyQ) disease associated with an expanded polyQ domain within the protein product of the ATXN2 gene. Interestingly, polyQ repeat expansions in ATXN2 are also associated with amyotrophic lateral sclerosis (ALS) and parkinsonism depending upon the length of the polyQ repeat expansion. The sequence encoding the polyQ repeat also varies with disease presentation: a pure CAG repeat is associated with SCA2, whereas the CAG repeat in ALS and parkinsonism is typically interrupted with the glutamine encoding CAA codon. Here, we asked if the purity of the CAG sequence encoding the polyQ repeat in ATXN2 could impact the toxicity of the ataxin-2 protein in vivo in Drosophila. We found that ataxin-2 encoded by a pure CAG repeat conferred toxicity in the retina and nervous system, whereas ataxin-2 encoded by a CAA-interrupted repeat or CAA-only repeat failed to confer toxicity, despite expression of the protein at similar levels. Furthermore, the CAG-encoded ataxin-2 protein aggregated in the fly eye, while ataxin-2 encoded by either a CAA/G or CAA repeat remained diffuse. The toxicity of the CAG-encoded ataxin-2 protein was also sensitive to the translation factor eIF4H, a known modifier of the toxic GGGGCC repeat in flies. These data indicate that ataxin-2 encoded by a pure CAG versus interrupted CAA/G polyQ repeat domain is associated with differential toxicity, indicating that mechanisms associated with the purity of the sequence of the polyQ domain contribute to disease.
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Affiliation(s)
- Leeanne McGurk
- Division of Cell & Developmental Biology, School of Life Sciences, University of Dundee, Dundee, UK
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Olivia M Rifai
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | | | | | - China N Byrns
- Neurosciences Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
- Medical Sciences Training Program, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Faith R Carranza
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Henry W Zhou
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Hyung-Jun Kim
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Yongqing Zhu
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Nancy M Bonini
- Department of Biology, University of Pennsylvania, Philadelphia, PA, USA
- Neurosciences Graduate Group, University of Pennsylvania, Philadelphia, PA, USA
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30
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Sechi S, Karimpour-Ghahnavieh A, Frappaolo A, Di Francesco L, Piergentili R, Schininà E, D’Avino PP, Giansanti MG. Identification of GOLPH3 Partners in Drosophila Unveils Potential Novel Roles in Tumorigenesis and Neural Disorders. Cells 2021; 10:cells10092336. [PMID: 34571985 PMCID: PMC8468827 DOI: 10.3390/cells10092336] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 09/01/2021] [Accepted: 09/03/2021] [Indexed: 12/28/2022] Open
Abstract
Golgi phosphoprotein 3 (GOLPH3) is a highly conserved peripheral membrane protein localized to the Golgi apparatus and the cytosol. GOLPH3 binding to Golgi membranes depends on phosphatidylinositol 4-phosphate [PI(4)P] and regulates Golgi architecture and vesicle trafficking. GOLPH3 overexpression has been correlated with poor prognosis in several cancers, but the molecular mechanisms that link GOLPH3 to malignant transformation are poorly understood. We recently showed that PI(4)P-GOLPH3 couples membrane trafficking with contractile ring assembly during cytokinesis in dividing Drosophila spermatocytes. Here, we use affinity purification coupled with mass spectrometry (AP-MS) to identify the protein-protein interaction network (interactome) of Drosophila GOLPH3 in testes. Analysis of the GOLPH3 interactome revealed enrichment for proteins involved in vesicle-mediated trafficking, cell proliferation and cytoskeleton dynamics. In particular, we found that dGOLPH3 interacts with the Drosophila orthologs of Fragile X mental retardation protein and Ataxin-2, suggesting a potential role in the pathophysiology of disorders of the nervous system. Our findings suggest novel molecular targets associated with GOLPH3 that might be relevant for therapeutic intervention in cancers and other human diseases.
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Affiliation(s)
- Stefano Sechi
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Angela Karimpour-Ghahnavieh
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Anna Frappaolo
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Laura Di Francesco
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Roberto Piergentili
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
| | - Eugenia Schininà
- Dipartimento di Scienze Biochimiche A. Rossi Fanelli, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (L.D.F.); (E.S.)
| | - Pier Paolo D’Avino
- Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge CB2 1QP, UK;
| | - Maria Grazia Giansanti
- Istituto di Biologia e Patologia Molecolari del CNR, c/o Dipartimento di Biologia e Biotecnologie, Sapienza Università di Roma, Piazzale A. Moro 5, 00185 Roma, Italy; (S.S.); (A.K.-G.); (A.F.); (R.P.)
- Correspondence: ; Tel.: +39-064-991-2555
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Rybak-Wolf A, Plass M. RNA Dynamics in Alzheimer's Disease. Molecules 2021; 26:5113. [PMID: 34500547 PMCID: PMC8433936 DOI: 10.3390/molecules26175113] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Revised: 08/09/2021] [Accepted: 08/17/2021] [Indexed: 02/06/2023] Open
Abstract
Alzheimer's disease (AD) is the most common age-related neurodegenerative disorder that heavily burdens healthcare systems worldwide. There is a significant requirement to understand the still unknown molecular mechanisms underlying AD. Current evidence shows that two of the major features of AD are transcriptome dysregulation and altered function of RNA binding proteins (RBPs), both of which lead to changes in the expression of different RNA species, including microRNAs (miRNAs), circular RNAs (circRNAs), long non-coding RNAs (lncRNAs), and messenger RNAs (mRNAs). In this review, we will conduct a comprehensive overview of how RNA dynamics are altered in AD and how this leads to the differential expression of both short and long RNA species. We will describe how RBP expression and function are altered in AD and how this impacts the expression of different RNA species. Furthermore, we will also show how changes in the abundance of specific RNA species are linked to the pathology of AD.
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Affiliation(s)
- Agnieszka Rybak-Wolf
- Max Delbrück Center for Molecular Medicine (MDC), Berlin Institute for Medical Systems Biology (BIMSB), 10115 Berlin, Germany
| | - Mireya Plass
- Gene Regulation of Cell Identity, Regenerative Medicine Program, Bellvitge Institute for Biomedical Research (IDIBELL), L'Hospitalet del Llobregat, 08908 Barcelona, Spain
- Program for Advancing Clinical Translation of Regenerative Medicine of Catalonia, P-CMR[C], L'Hospitalet del Llobregat, 08908 Barcelona, Spain
- Center for Networked Biomedical Research on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), 28029 Madrid, Spain
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Anticipation Can Be More Common in Hereditary Spastic Paraplegia with SPAST Mutations Than It Appears. Can J Neurol Sci 2021; 49:651-661. [PMID: 34353391 DOI: 10.1017/cjn.2021.188] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND AND OBJECTIVE Hereditary spastic paraplegia (HSP) is a heterogeneous neurodegenerative disorder with lower-limb spasticity and weakness. Different patterns of inheritance have been identified in HSP. Most autosomal-dominant HSPs (AD-HSPs) are associated with mutations of the SPAST gene (SPG4), leading to a pure form of HSP with variable age-at-onset (AAO). Anticipation, an earlier onset of disease, as well as aggravation of symptoms in successive generations, may be correlated to SPG4. Herein, we suggested that anticipation might be a relatively common finding in SPG4 families. METHODS Whole-exome sequencing was done on DNA of 14 unrelated Iranian AD-HSP probands. Data were analyzed, and candidate variants were PCR-amplified and sequenced by the Sanger method, subsequently checked in family members to co-segregation analysis. Multiplex ligation-dependent probe amplification (MLPA) was done for seven probands. Clinical features of the probands were recorded, and the probable anticipation was checked in these families. Other previous reported SPG4 families were investigated to anticipation. RESULTS Our findings showed that SPG4 was the common subtype of HSP; three families carried variants in the KIF5A, ATL1, and MFN2 genes, while five families harbored mutations in the SPAST gene. Clinical features of only SPG4 families indicated decreasing AAO in affected individuals of the successive generations, and this difference was significant (p-value <0.05). CONCLUSION It seems SPAST will be the first candidate gene in families that manifests a pure form of AD-HSP and anticipation. Therefore, it may be a powerful situation of genotype-phenotype correlation. However, the underlying mechanism of anticipation in these families is not clear yet.
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Abstract
PURPOSE OF REVIEW To provide an update on the role of Ataxin-2 gene (ATXN2) in health and neurological diseases. RECENT FINDINGS There is a growing complexity emerging on the role of ATXN2 and its variants in association with SCA2 and several other neurological diseases. Polymorphisms and intermediate alleles in ATXN2 establish this gene as a powerful modulator of neurological diseases including lethal neurodegenerative conditions such as motor neuron disease, spinocerebellar ataxia 3 (SCA3), and peripheral nerve disease such as familial amyloidosis polyneuropathy. This role is in fact far wider than the previously described for polymorphism in the prion protein (PRNP) gene. Positive data from antisense oligo therapy in a murine model of SCA2 suggest that similar approaches may be feasible in humans SCA2 patients. SUMMARY ATXN2 is one of the few genes where a single gene causes several diseases and/or modifies several and disparate neurological disorders. Hence, understanding mutagenesis, genetic variants, and biological functions will help managing SCA2, and several human diseases connected with dysfunctional pathways in the brain, innate immunity, autophagy, cellular, lipid, and RNA metabolism.
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Affiliation(s)
- Jose Miguel Laffita-Mesa
- Department of Clinical Neuroscience (CNS), J5:20 Bioclinicum, Karolinska University Hospital, Stockholm, Sweden
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Rodríguez-Labrada R, Batista-Izquierdo A, González-Melix Z, Reynado-Cejas L, Vázquez-Mojena Y, Sanz YA, Canales-Ochoa N, González-Zaldívar Y, Dogan I, Reetz K, Velázquez-Pérez L. Cognitive Decline Is Closely Associated with Ataxia Severity in Spinocerebellar Ataxia Type 2: a Validation Study of the Schmahmann Syndrome Scale. THE CEREBELLUM 2021; 21:391-403. [PMID: 34313938 DOI: 10.1007/s12311-021-01305-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/05/2021] [Indexed: 01/10/2023]
Abstract
The cerebellar cognitive affective syndrome scale (CCAS-S) was designed to detect specific cognitive dysfunctions in cerebellar patients but is scarcely validated in spinocerebellar ataxias (SCA). The objective of this study is to determine the usefulness of the CCAS-S in a Cuban cohort of SCA2 patients and the relationship of its scores with disease severity. The original scale underwent a forward and backward translation into Spanish language, followed by a pilot study to evaluate its comprehensibility. Reliability, discriminant, and convergent validity assessments were conducted in 64 SCA2 patients and 64 healthy controls matched for sex, age, and education. Fifty patients completed the Montreal Cognitive Assessment (MoCA) test. The CCAS-S showed an acceptable internal consistency (Cronbach's alpha = 0.74) while its total raw score and the number of failed tests showed excellent (ICC = 0.94) and good (ICC = 0.89) test-retest reliability, respectively. Based on original cut-offs, the sensitivity of CCAS-S to detect possible/probable/definite CCAS was notably high (100%/100%/91%), but specificities were low (6%/30/64%) because the decreased specificity observed in four items. CCAS-S performance was significantly influenced by ataxia severity in patients and by education in both groups. CCAS-S scores correlated with MoCA scores, but showed higher sensitivity than MoCA to detect cognitive impairments in patients. The CCAS-S is particularly useful to detect cognitive impairments in SCA2 but some transcultural and/or age and education-dependent adaptations could be necessary to improve its diagnostic properties. Furthermore, this scale confirmed the parallelism between cognitive and motor deficits in SCA2, giving better insights into the disease pathophysiology and identifying novel outcomes for clinical trials.
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Affiliation(s)
- Roberto Rodríguez-Labrada
- Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.
- Cuban Center for Neurosciences, 190st between 25st and 27st, Cubanacan, Playa, 11300, Havana, Cuba.
| | | | | | | | - Yaimeé Vázquez-Mojena
- Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
- Cuban Center for Neurosciences, 190st between 25st and 27st, Cubanacan, Playa, 11300, Havana, Cuba
| | | | - Nalia Canales-Ochoa
- Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
| | | | - Imis Dogan
- Department of Neurology, RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Juelich Research Center GmbH and RWTH Aachen University, Aachen, Germany
| | - Kathrin Reetz
- Department of Neurology, RWTH Aachen University, Aachen, Germany
- JARA-BRAIN Institute Molecular Neuroscience and Neuroimaging, Juelich Research Center GmbH and RWTH Aachen University, Aachen, Germany
| | - Luis Velázquez-Pérez
- Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.
- Cuban Academy of Sciences, Cuba st 460, Between Teniente Rey St and Compostela St, Habana Vieja, 19100, Havana, Cuba.
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mGluR1 signaling in cerebellar Purkinje cells: Subcellular organization and involvement in cerebellar function and disease. Neuropharmacology 2021; 194:108629. [PMID: 34089728 DOI: 10.1016/j.neuropharm.2021.108629] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 05/19/2021] [Accepted: 05/20/2021] [Indexed: 11/20/2022]
Abstract
The cerebellum is essential for the control, coordination, and learning of movements, and for certain aspects of cognitive function. Purkinje cells are the sole output neurons in the cerebellar cortex and therefore play crucial roles in the diverse functions of the cerebellum. The type 1 metabotropic glutamate receptor (mGluR1) is prominently enriched in Purkinje cells and triggers downstream signaling pathways that are required for functional and structural plasticity, and for synaptic responses. To understand how mGluR1 contributes to cerebellar functions, it is important to consider not only the operational properties of this receptor, but also its spatial organization and the molecular interactions that enable its proper functioning. In this review, we highlight how mGluR1 and its related signaling molecules are organized into tightly coupled microdomains to fulfill physiological functions. We also describe emerging evidence that altered mGluR1 signaling in Purkinje cells underlies cerebellar dysfunction in ataxias of human patients and mouse models.
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Sena LS, Dos Santos Pinheiro J, Hasan A, Saraiva-Pereira ML, Jardim LB. Spinocerebellar ataxia type 2 from an evolutionary perspective: Systematic review and meta-analysis. Clin Genet 2021; 100:258-267. [PMID: 33960424 DOI: 10.1111/cge.13978] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 04/19/2021] [Accepted: 05/05/2021] [Indexed: 01/27/2023]
Abstract
Dominant diseases due to expanded CAG repeat tracts, such as spinocerebellar ataxia type 2 (SCA2), are prone to anticipation and worsening of clinical picture in subsequent generations. There is insufficient data about selective forces acting on the maintenance of these diseases in populations. We made a systematic review and meta-analysis on the effect of the CAG length over age at onset, instability of transmissions, anticipation, de novo or sporadic cases, fitness, segregation of alleles, and ancestral haplotypes. The correlation between CAG expanded and age at onset was r2 = 0.577, and transmission of the mutant allele was associated with an increase of 2.42 CAG repeats in the next generation and an anticipation of 14.62 years per generation, on average. One de novo and 18 sporadic cases were detected. Affected SCA2 individuals seem to have more children than controls. The expanded allele was less segregated than the 22-repeat allele in children of SCA2 subjects. Several ancestral SCA2 haplotypes were published. Data suggest that SCA2 lineages may tend to disappear eventually, due to strong anticipation phenomena. Whether or not the novel cases come from common haplotypes associated with a predisposition to further expansions is a question that needs to be addressed by future studies.
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Affiliation(s)
- Lucas Schenatto Sena
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Jordânia Dos Santos Pinheiro
- Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Ali Hasan
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Maria Luiza Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Instituto de Genética Médica Populacional, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Laura Bannach Jardim
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.,Centros de Pesquisa Clínica e Experimental, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Instituto de Genética Médica Populacional, Porto Alegre, Brazil.,Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil.,Departamento de Medicina Interna, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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37
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Amado DA, Davidson BL. Gene therapy for ALS: A review. Mol Ther 2021; 29:3345-3358. [PMID: 33839324 DOI: 10.1016/j.ymthe.2021.04.008] [Citation(s) in RCA: 94] [Impact Index Per Article: 31.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 02/28/2021] [Accepted: 04/05/2021] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) has historically posed unique challenges for gene-therapy-based approaches, due to a paucity of therapeutic targets as well as the difficulty of accessing both the brain and spinal cord. Recent advances in our understanding of disease mechanism and ALS genetics, however, have combined with tremendous strides in CNS targeting, gene delivery, and gene editing and knockdown techniques to open new horizons of therapeutic possibility. Gene therapy clinical trials are currently underway for ALS patients with SOD1 mutations, C9orf72 hexanucleotide repeat expansions, ATXN2 trinucleotide expansions, and FUS mutations, as well as sporadic disease without known genetic cause. In this review, we provide an in-depth exploration of the state of ALS-directed gene therapy, including antisense oligonucleotides, RNA interference, CRISPR, adeno-associated virus (AAV)-mediated trophic support, and antibody-based methods. We discuss how each of these approaches has been implemented across known genetic causes as well as sporadic ALS, reviewing preclinical studies as well as completed and ongoing human clinical trials. We highlight the transformative potential of these evolving technologies as the gene therapy field advances toward a true disease-modifying treatment for this devastating illness.
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Affiliation(s)
- Defne A Amado
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Beverly L Davidson
- Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA.
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Darling AL, Shorter J. Combating deleterious phase transitions in neurodegenerative disease. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2021; 1868:118984. [PMID: 33549703 PMCID: PMC7965345 DOI: 10.1016/j.bbamcr.2021.118984] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 01/21/2021] [Accepted: 01/22/2021] [Indexed: 12/11/2022]
Abstract
Protein aggregation is a hallmark of neurodegenerative diseases. However, the mechanism that induces pathogenic aggregation is not well understood. Recently, it has emerged that several of the pathological proteins found in an aggregated or mislocalized state in neurodegenerative diseases are also able to undergo liquid-liquid phase separation (LLPS) under physiological conditions. Although these phase transitions are likely important for various physiological functions, neurodegenerative disease-related mutations and conditions can alter the LLPS behavior of these proteins, which can elicit toxicity. Therefore, therapeutics that antagonize aberrant LLPS may be able to mitigate toxicity and aggregation that is ubiquitous in neurodegenerative disease. Here, we discuss the mechanisms by which aberrant protein phase transitions may contribute to neurodegenerative disease. We also outline potential therapeutic strategies to counter deleterious phases. State without borders: Membrane-less organelles and liquid-liquid phase transitions edited by Vladimir N Uversky.
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Affiliation(s)
- April L Darling
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - James Shorter
- Department of Biochemistry and Biophysics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA.
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The ATXN2 Orthologs CID3 and CID4, Act Redundantly to In-Fluence Developmental Pathways throughout the Life Cycle of Arabidopsis thaliana. Int J Mol Sci 2021; 22:ijms22063068. [PMID: 33802796 PMCID: PMC8002431 DOI: 10.3390/ijms22063068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/15/2021] [Accepted: 02/15/2021] [Indexed: 11/17/2022] Open
Abstract
RNA-binding proteins (RBPs) are key elements involved in post-transcriptional regulation. Ataxin-2 (ATXN2) is an evolutionarily conserved RBP protein, whose function has been studied in several model organisms, from Saccharomyces cerevisiae to the Homo sapiens. ATXN2 interacts with poly(A) binding proteins (PABP) and binds to specific sequences at the 3'UTR of target mRNAs to stabilize them. CTC-Interacting Domain3 (CID3) and CID4 are two ATXN2 orthologs present in plant genomes whose function is unknown. In the present study, phenotypical and transcriptome profiling were used to examine the role of CID3 and CID4 in Arabidopsis thaliana. We found that they act redundantly to influence pathways throughout the life cycle. cid3cid4 double mutant showed a delay in flowering time and a reduced rosette size. Transcriptome profiling revealed that key factors that promote floral transition and floral meristem identity were downregulated in cid3cid4 whereas the flowering repressor FLOWERING LOCUS C (FLC) was upregulated. Expression of key factors in the photoperiodic regulation of flowering and circadian clock pathways, were also altered in cid3cid4, as well as the expression of several transcription factors and miRNAs encoding genes involved in leaf growth dynamics. These findings reveal that ATXN2 orthologs may have a role in developmental pathways throughout the life cycle of plants.
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Dennis AG, Almaguer-Mederos LE, Raúl RA, Roberto RL, Luis VP, Dany CA, Yanetza GZ, Yaimeé VM, Annelié ED, Arnoy PA, Reydenis TV. Redox Imbalance Associates with Clinical Worsening in Spinocerebellar Ataxia Type 2. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:9875639. [PMID: 33688396 PMCID: PMC7920744 DOI: 10.1155/2021/9875639] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 12/24/2020] [Accepted: 02/05/2021] [Indexed: 12/30/2022]
Abstract
BACKGROUND Spinocerebellar ataxia type 2 (SCA2) is a neurodegenerative disease presenting with redox imbalance. However, the nature and implications of redox imbalance in SCA2 physiopathology have not been fully understood. OBJECTIVE The objective of this study is to assess the redox imbalance and its association with disease severity in SCA2 mutation carriers. METHODS A case-control study was conducted involving molecularly confirmed SCA2 patients, presymptomatic individuals, and healthy controls. Several antioxidant parameters were assessed, including serum thiol concentration and the superoxide dismutase, catalase, and glutathione S-transferase enzymatic activities. Also, several prooxidant parameters were evaluated, including thiobarbituric acid-reactive species and protein carbonyl concentrations. Damage, protective, and OXY scores were computed. Clinical correlates were established. RESULTS Significant differences were found between comparison groups for redox markers, including protein carbonyl concentration (F = 3.30; p = 0.041), glutathione S-transferase activity (F = 4.88; p = 0.009), and damage (F = 3.20; p = 0.045), protection (F = 12.75; p < 0.001), and OXY (F = 7.29; p = 0.001) scores. Protein carbonyl concentration was positively correlated with CAG repeat length (r = 0.27; p = 0.022), while both protein carbonyl concentration (r = -0.27; p = 0.018) and OXY score (r = -0.25; p = 0.013) were inversely correlated to the disease duration. Increasing levels of antioxidants and decreasing levels of prooxidant parameters were associated with clinical worsening. CONCLUSIONS There is a disruption of redox balance in SCA2 mutation carriers which depends on the disease stage. Besides, redox changes associate with markers of disease severity, suggesting a link between disruption of redox balance and SCA2 physiopathology.
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Affiliation(s)
- Almaguer-Gotay Dennis
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- University of Medical Sciences of Holguín, Cuba
| | - Luis E. Almaguer-Mederos
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- University of Medical Sciences of Holguín, Cuba
| | - Rodríguez-Aguilera Raúl
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- University of Medical Sciences of Holguín, Cuba
| | | | - Velázquez-Pérez Luis
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- Cuban Academy of Sciences, Cuba
| | - Cuello-Almarales Dany
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- University of Medical Sciences of Holguín, Cuba
| | - González-Zaldívar Yanetza
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
- University of Medical Sciences of Holguín, Cuba
| | - Vázquez-Mojena Yaimeé
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
| | | | - Peña-Acosta Arnoy
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
| | - Torres-Vega Reydenis
- Center for the Investigation and Rehabilitation of Hereditary Ataxias (CIRAH), Holguín, Cuba
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Almaguer-Mederos LE, Pérez-Ávila I, Aguilera-Rodríguez R, Velázquez-Garcés M, Almaguer-Gotay D, Hechavarría-Pupo R, Rodríguez-Estupiñán A, Auburger G. Body Mass Index Is Significantly Associated With Disease Severity in Spinocerebellar Ataxia Type 2 Patients. Mov Disord 2021; 36:1372-1380. [PMID: 33548146 DOI: 10.1002/mds.28498] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 12/09/2020] [Accepted: 12/21/2020] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Spinocerebellar ataxia type 2 is a progressive neurodegenerative disorder due to an unstable expansion of a CAG repeat in the ATXN2 gene. Although weight loss has been associated with disease progression in several neurodegenerative conditions, it has been barely assessed in patients with spinocerebellar ataxia type 2. OBJECTIVE The objective of this study was to test whether body mass index is altered in patients with spinocerebellar ataxia type 2 with varying expansion sizes from early to late disease stages. METHODS A cross-sectional case-control study was performed, which included 222 clinically and molecularly diagnosed patients and 214 sex- and age-matched healthy individuals. ATXN2 genotypes and sex were considered as risk factors. Clinical outcomes included the body mass index, age at onset, disease duration, Scale for the Assessment and Rating of Ataxia score, disease stage, dysphagia, and progression rate. Multiple linear regression models were generated. RESULTS Body mass index was significantly decreased in male patients, but not in female patients, relative to control subjects. In addition to sex, body mass index was significantly associated with age at onset and progression rate. Conversely, body mass index, along with repeat length in ATXN2 expanded alleles and disease duration, was associated with Scale for the Assessment and Rating of Ataxia score. In addition, body mass index, along with the age at onset and the repeat length in ATXN2 normal and expanded alleles, has a significant influence on progression rate. CONCLUSIONS Body mass index might be a useful biomarker of disease severity, particularly in male patients with spinocerebellar ataxia type 2 in the context of nutritional interventions or clinical trials assessing the efficacy of promising new drugs. © 2021 International Parkinson and Movement Disorder Society.
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Affiliation(s)
| | - Ilbedis Pérez-Ávila
- Center for the Investigation and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.,Center for Sports Medicine, Holguín, Cuba
| | | | | | - Dennis Almaguer-Gotay
- Center for the Investigation and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
| | | | | | - Georg Auburger
- Experimental Neurology, Goethe University Medical Faculty, Frankfurt, Germany
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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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Monckton DG. The Contribution of Somatic Expansion of the CAG Repeat to Symptomatic Development in Huntington's Disease: A Historical Perspective. J Huntingtons Dis 2021; 10:7-33. [PMID: 33579863 PMCID: PMC7990401 DOI: 10.3233/jhd-200429] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The discovery in the early 1990s of the expansion of unstable simple sequence repeats as the causative mutation for a number of inherited human disorders, including Huntington's disease (HD), opened up a new era of human genetics and provided explanations for some old problems. In particular, an inverse association between the number of repeats inherited and age at onset, and unprecedented levels of germline instability, biased toward further expansion, provided an explanation for the wide symptomatic variability and anticipation observed in HD and many of these disorders. The repeats were also revealed to be somatically unstable in a process that is expansion-biased, age-dependent and tissue-specific, features that are now increasingly recognised as contributory to the age-dependence, progressive nature and tissue specificity of the symptoms of HD, and at least some related disorders. With much of the data deriving from affected individuals, and model systems, somatic expansions have been revealed to arise in a cell division-independent manner in critical target tissues via a mechanism involving key components of the DNA mismatch repair pathway. These insights have opened new approaches to thinking about how the disease could be treated by suppressing somatic expansion and revealed novel protein targets for intervention. Exciting times lie ahead in turning these insights into novel therapies for HD and related disorders.
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Affiliation(s)
- Darren G. Monckton
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, UK
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44
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Nakamori M, Mochizuki H. Targeting Expanded Repeats by Small Molecules in Repeat Expansion Disorders. Mov Disord 2020; 36:298-305. [DOI: 10.1002/mds.28397] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 10/20/2020] [Accepted: 10/26/2020] [Indexed: 12/14/2022] Open
Affiliation(s)
- Masayuki Nakamori
- Department of Neurology Osaka University Graduate School of Medicine Osaka Japan
| | - Hideki Mochizuki
- Department of Neurology Osaka University Graduate School of Medicine Osaka Japan
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Yang L, Dong Y, Ma Y, Ni W, Wu ZY. Genetic profile and clinical characteristics of Chinese patients with spinocerebellar ataxia type 2: A multicenter experience over 10 years. Eur J Neurol 2020; 28:955-964. [PMID: 33070405 DOI: 10.1111/ene.14601] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 10/14/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND PURPOSE Spinocerebellar ataxia type 2 (SCA2) is the second most common type of spinocerebellar ataxia in China. However, data on the clinical and genetic features of Chinese SCA2 patients are scarce. This study aims to provide a comprehensive description of in the Chinese SCA2 cohort. METHODS A total of 135 patients with SCA2 from 92 families and 104 unrelated normal controls were recruited from three medical centers between 2008 and 2020. Sanger sequencing and TA cloning were used to determine the CAG repeat length and intrinsic structure. The clinical data of patients with SCA2, including electromyography, magnetic resonance imaging, positron-emission tomography, and clinical scale scores, were recorded. RESULTS The mean ± SD age at onset of SCA2 patients was 32.6 ± 11.9 years and the corresponding CAG repeat length was 42.1 ± 3.6. CAG repeat length accounted for 64% of the age-at-onset variance. We observed that patients had a significantly lower proportion of (CAG)8 CAA(CAG)4 CAA(CAG)8 within normal alleles than normal controls (48.8% vs. 64.9%; p = 0.003), while the distribution of the proportion of (CAG)13 CAA (CAG)8 was the opposite. Peripheral neuropathy was frequent, occurring in 75.9% of the patients. Parkinsonism was relatively common, with a frequency of 11.8%. Two patients with parkinsonism had a significantly more severe reduction in dopamine transporter levels in the bilateral striatum than the one patient with pure ataxia. An infant-onset case of SCA2 with more than 180 CAG repeats was characterized by global development delay, hypotonia and hearing impairment. CONCLUSIONS This study describes the genetic profile and clinical characteristics of the largest SCA2 cohort to date in the Chinese population and analyzes inter-population differences. Many aspects of this study population were different from other populations with SCA2.
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Affiliation(s)
- Lu Yang
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Yi Dong
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology, Huashan Hospital, Fudan University, Shanghai, China
| | - Yin Ma
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China
| | - Wang Ni
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology, First Affiliated Hospital, Fujian Medical University, Fuzhou, China
| | - Zhi-Ying Wu
- Department of Neurology and Research Center of Neurology in Second Affiliated Hospital, and Key Laboratory of Medical Neurobiology of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai, China
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46
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Watanabe R, Higashi S, Nonaka T, Kawakami I, Oshima K, Niizato K, Akiyama H, Yoshida M, Hasegawa M, Arai T. Intracellular dynamics of Ataxin-2 in the human brains with normal and frontotemporal lobar degeneration with TDP-43 inclusions. Acta Neuropathol Commun 2020; 8:176. [PMID: 33115537 PMCID: PMC7594343 DOI: 10.1186/s40478-020-01055-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 10/10/2020] [Indexed: 12/15/2022] Open
Abstract
TAR DNA-binding protein of 43 kDa (TDP-43) is a major component of intracellular aggregates formed in brains of the patients with frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), which are correctively referred to as TDP-43 proteinopathies. A link between Ataxin-2 (ATXN2) and TDP-43 proteinopathies was established when intermediate CAG repeat expansions of ATXN2 gene were found to be associated with ALS and it was shown that ATXN2 modifies TDP-43 toxicity. Although ATXN2's contribution to TDP-43 proteinopathies has been mostly studied in ALS, recent studies have shown that intermediate repeat expansions of ATXN2 also influence the phenotype of FTLD by an unknown mechanism. To address this issue, we immunohistochemically and biochemically analyzed the intracellular dynamics of ATXN2 in brains of normal controls and FTLD-TDP cases. The immunohistochemical studies revealed that ATXN2 localized in the neuronal cytoplasm and proximal dendrites, and expressed widely and uniformly in normal human brains. A semi-quantitative immunofluorescent analysis of normal brains revealed that the cytoplasmic ATXN2 strongly associates with ribosomal protein S6 and poly-A binding protein 1 and partially overlaps with the endoplasmic reticulum marker Calnexin, suggesting a major role of ATXN2 in protein synthesis. The results of immunohistochemical and biochemical analyses of brains from FTLD-TDP cases showed the colocalization of ATXN2 and phosphorylated TDP-43 in the dystrophic neurites and the neuronal cytoplasmic inclusions in the hippocampal region, and a significant reduction of ATXN2 protein compared to controls. These results suggest that ATXN2 is involved in the pathological process of FTLD-TDP. It remains to be clarified whether reduced ATXN2 expression induces neurodegeneration by impairing protein synthesis or plays a neuroprotective role by attenuating the toxicity of TDP-43 aggregates in FTLD-TDP and other TDP-43 proteinopathies.
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Affiliation(s)
- Ryohei Watanabe
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo Japan
- Department of Psychiatry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki Japan
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, 2-1-1 Kamikitazawa, Setagaya, Tokyo Japan
| | - Shinji Higashi
- Department of Psychiatry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki Japan
- Department of Psychiatry, Tokyo Medical University Ibaraki Medical Center, 3-20-1 Chuo, Ami, Inashiki, Ibaraki Japan
| | - Takashi Nonaka
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo Japan
| | - Ito Kawakami
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo Japan
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, 2-1-1 Kamikitazawa, Setagaya, Tokyo Japan
- Brain Bank for Aging Research, Department of Neuropathology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi, Tokyo Japan
| | - Kenichi Oshima
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, 2-1-1 Kamikitazawa, Setagaya, Tokyo Japan
| | - Kazuhiro Niizato
- Department of Psychiatry, Tokyo Metropolitan Matsuzawa Hospital, 2-1-1 Kamikitazawa, Setagaya, Tokyo Japan
| | - Haruhiko Akiyama
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo Japan
- Department of Clinical Research, Yokohama Brain and Spine Center, 1-2-1 Takigashira, Isogo, Yokohama, Kanagawa Japan
| | - Mari Yoshida
- Institute for Medical Science of Aging, Aichi Medical University, 1-1 Yazakokarimata, Nagakute, Aichi Japan
| | - Masato Hasegawa
- Dementia Research Project, Tokyo Metropolitan Institute of Medical Science, 2-1-6 Kamikitazawa, Setagaya, Tokyo Japan
| | - Tetsuaki Arai
- Department of Psychiatry, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki Japan
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Velázquez-Pérez L, Rodriguez-Labrada R, González-Garcés Y, Arrufat-Pie E, Torres-Vega R, Medrano-Montero J, Ramirez-Bautista B, Vazquez-Mojena Y, Auburger G, Horak F, Ziemann U, Gomez CM. Prodromal Spinocerebellar Ataxia Type 2 Subjects Have Quantifiable Gait and Postural Sway Deficits. Mov Disord 2020; 36:471-480. [PMID: 33107647 DOI: 10.1002/mds.28343] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/14/2020] [Accepted: 09/29/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND The search for valid preclinical biomarkers of cerebellar dysfunction is a key research goal for the upcoming era of early interventional approaches in spinocerebellar ataxias. This study aims to describe novel preclinical biomarkers of subtle gait and postural sway abnormalities in prodromal spinocerebellar ataxia type 2 (pre-SCA2). METHODS Thirty pre-SCA2 patients and their matched healthy controls underwent quantitative assessments of gait and postural sway using a wearable sensor-based system and semiquantitative evaluation of cerebellar features by SARA (Scale for the Assessment and Rating of Ataxia) score. RESULTS Quantitative analysis of natural gait showed a significantly larger variability of the swing period, toe-off angle and toe-out angle in pre-SCA2, and larger mean coronal and transverse ranges of motion of the trunk at the lumbar location and of the sagittal range of motion of the trunk at the sternum location compared to controls. During tandem gait, pre-SCA2 subjects showed larger lumbar, trunk, and arm ranges of motion than controls. Postural sway analysis showed excessive body oscillation that was increased in tandem stance. Overall, these abnormalities were detected in pre-SCA2 patients without clinical evidence of abnormalities in SARA. The toe-off angle and swing time variability were significantly correlated with the time to ataxia onset, whereas the toe-off angle and transverse range of motion at trunk position during tandem gait were significantly associated with the SARA score. CONCLUSIONS This study demonstrates early alteration of gait and postural sway control in prodromal SCA2 using a wearable sensor-based system. This offers new pathophysiological hints into this early disease stage and provides novel potential biomarkers for future clinical trials. © 2020 International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Luis Velázquez-Pérez
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.,Cuban Academy of Sciences, La Habana Vieja, Cuba
| | - Roberto Rodriguez-Labrada
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.,Department of Molecular Biology, Cuban Neuroscience Centre, Playa, Cuba
| | - Yasmani González-Garcés
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
| | - Eduardo Arrufat-Pie
- Department of Neurorehabilitation, Clinical & Surgical Hospital "Manuel Piti Fajardo,", Plaza de la Revolución, Cuba
| | - Reidenis Torres-Vega
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
| | - Jacqueline Medrano-Montero
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba
| | | | - Yaimeé Vazquez-Mojena
- Department of Clinical Neurophysiology, Centre for the Research and Rehabilitation of Hereditary Ataxias, Holguín, Cuba.,Department of Molecular Biology, Cuban Neuroscience Centre, Playa, Cuba
| | - Georg Auburger
- Experimental Neurology, Department of Neurology, Experimental Neurology, Medical School, Goethe University, Frankfurt am Main, Germany
| | - Fay Horak
- Department of Neurology, Oregon Health and Science University, Portland, Oregon, USA
| | - Ulf Ziemann
- Department of Neurology & Stroke, University of Tübingen, Tübingen, Germany.,Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
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Laffita-Mesa JM, Nennesmo I, Paucar M, Svenningsson P. A Novel Duplication in ATXN2 as Modifier for Spinocerebellar Ataxia 3 (SCA3) and C9ORF72-ALS. Mov Disord 2020; 36:508-514. [PMID: 33058338 PMCID: PMC7983901 DOI: 10.1002/mds.28334] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 09/04/2020] [Accepted: 09/21/2020] [Indexed: 11/30/2022] Open
Abstract
Background The ataxin‐2 (ATXN2) gene contains a cytosine‐adenine‐guanine repeat sequence ranging from 13 to 31 repeats, but when surpassing certain thresholds causes neurodegeneration. Genetic alterations in ATXN2 other than pathological cytosine adenine guanine (CAG) repeats are unknown. Methods/Results We have identified a 9–base pair duplication in the 2‐gene ATXN2 sense/antisense region. The duplication was found in a Swedish family with spinocerebellar ataxia 3 with parkinsonism, conferring a deviated age at onset unexplained by the concomitant presence of ATXN2 intermediate alleles. Similarly, C9ORF72 amyotrophic lateral sclerosis cases bearing the same duplication had earlier age at onset than those with C9ORF72 and ATXN2 intermediate alleles. No effect was evident in Parkinson's disease (PD) cases without known PD gene mutations. Conclusions We describe the first genetic alteration other than the known intermediate‐range CAG repeats in ATXN2. This 9–base pair duplication may act as an additional hit among carriers of pathological nucleotide expansions in ATXN3 and C9ORF72 with ATXN2 intermediate. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.
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Affiliation(s)
- Jose Miguel Laffita-Mesa
- Department of Clinical Neuroscience (CNS), Neuro Svenningsson, J5:20 Bioclinicum, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Inger Nennesmo
- Department of Clinical Neuroscience (CNS), Neuro Svenningsson, J5:20 Bioclinicum, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Martin Paucar
- Department of Clinical Neuroscience (CNS), Neuro Svenningsson, J5:20 Bioclinicum, Karolinska Universitetssjukhuset, Stockholm, Sweden
| | - Per Svenningsson
- Department of Clinical Neuroscience (CNS), Neuro Svenningsson, J5:20 Bioclinicum, Karolinska Universitetssjukhuset, Stockholm, Sweden
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49
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Lowry JL, Ryan ÉB, Esengul YT, Siddique N, Siddique T. Intricacies of aetiology in intrafamilial degenerative disease. Brain Commun 2020; 2:fcaa120. [PMID: 33134917 PMCID: PMC7585693 DOI: 10.1093/braincomms/fcaa120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 06/23/2020] [Accepted: 07/10/2020] [Indexed: 02/07/2023] Open
Abstract
The genetic underpinnings of late-onset degenerative disease have typically been determined by screening families for the segregation of genetic variants with the disease trait in affected, but not unaffected, individuals. However, instances of intrafamilial etiological heterogeneity, where pathogenic variants in a culprit gene are not shared among all affected family members, continue to emerge and confound gene-discovery and genetic counselling efforts. Discordant intrafamilial cases lacking a mutation shared by other affected family members are described as disease phenocopies. This description often results in an over-simplified acceptance of an environmental cause of disease in the phenocopy cases, while the role of intrafamilial genetic heterogeneity, shared de novo mutations or epigenetic aberrations in such families is often ignored. On a related note, it is now evident that the same disease-associated variant can be present in individuals exhibiting clinically distinct phenotypes, thereby genetically uniting seemingly unrelated syndromes to form a spectrum of disease. Herein, we discuss the intricacies of determining complex degenerative disease aetiology and suggest alternative mechanisms of disease transmission that may account for the apparent missing heritability of disease.
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Affiliation(s)
- Jessica L Lowry
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Éanna B Ryan
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Y Taylan Esengul
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Nailah Siddique
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
| | - Teepu Siddique
- The Ken and Ruth Davee Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Northwestern University Interdepartmental Neuroscience Program, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA.,Department of Pathology Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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50
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Tejwani L, Lim J. Pathogenic mechanisms underlying spinocerebellar ataxia type 1. Cell Mol Life Sci 2020; 77:4015-4029. [PMID: 32306062 PMCID: PMC7541529 DOI: 10.1007/s00018-020-03520-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 03/06/2020] [Accepted: 04/06/2020] [Indexed: 02/06/2023]
Abstract
The family of hereditary cerebellar ataxias is a large group of disorders with heterogenous clinical manifestations and genetic etiologies. Among these, over 30 autosomal dominantly inherited subtypes have been identified, collectively referred to as the spinocerebellar ataxias (SCAs). Generally, the SCAs are characterized by a progressive gait impairment with classical cerebellar features, and in a subset of SCAs, accompanied by extra-cerebellar features. Beyond the common gait impairment and cerebellar atrophy, the wide range of additional clinical features observed across the SCAs is likely explained by the diverse set of mutated genes that encode proteins with seemingly disparate functional roles in nervous system biology. By synthesizing knowledge obtained from studies of the various SCAs over the past several decades, convergence onto a few key cellular changes, namely ion channel dysfunction and transcriptional dysregulation, has become apparent and may represent central mechanisms of cerebellar disease pathogenesis. This review will detail our current understanding of the molecular pathogenesis of the SCAs, focusing primarily on the first described autosomal dominant spinocerebellar ataxia, SCA1, as well as the emerging common core mechanisms across the various SCAs.
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Affiliation(s)
- Leon Tejwani
- Interdepartmental Neuroscience Program, Yale School of Medicine, 295 Congress Avenue, New Haven, CT, 06510, USA
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Janghoo Lim
- Interdepartmental Neuroscience Program, Yale School of Medicine, 295 Congress Avenue, New Haven, CT, 06510, USA.
- Department of Neuroscience, Yale School of Medicine, New Haven, CT, 06510, USA.
- Department of Genetics, Yale School of Medicine, New Haven, CT, 06510, USA.
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale School of Medicine, New Haven, CT, 06510, USA.
- Yale Stem Cell Center, Yale School of Medicine, New Haven, CT, 06510, USA.
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