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Nassisi M, Coarelli G, Blanchard B, Dubec-Fleury C, Drine K, Kitic N, Sancho S, Hilab R, Tezenas du Montcel S, Junge C, Lane R, Arnold HM, Durr A, Audo I. ATXN7-Related Cone-Rod Dystrophy: The Integrated Functional Evaluation of the Cerebellum (CERMOI) Study. JAMA Ophthalmol 2024; 142:301-308. [PMID: 38421662 PMCID: PMC10905377 DOI: 10.1001/jamaophthalmol.2024.0001] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Accepted: 12/15/2023] [Indexed: 03/02/2024]
Abstract
Importance Reliable biomarkers with diagnostic and prognostic values are needed for upcoming gene therapy trials for spinocerebellar ataxias. Objective To identify ophthalmological biomarkers in a sample of spinocerebellar ataxia type 7 (SCA7) carriers. Design, Setting, and Participants This article presents baseline data from a cross-sectional natural history study conducted in Paris, France, reference centers for rare diseases from May 2020 to April 2021. Data were analyzed from September to December 2022. Fifteen adult ATXN7 pathogenic expansion carriers (9 with preataxia and 6 with ataxia) were included, all with a Scale for the Assessment and Rating of Ataxia (SARA) score of 15 of 40 or lower. Patients were recruited at the Paris Brain Institute, and all contacted patients accepted to participate in the study. Main Outcomes and Measures Three visits (baseline, 6 months, and 12 months) were planned, including neurological examination (SARA and Composite Cerebellar Functional Severity Score), ophthalmological examination (best-corrected visual acuity, microperimetry, full-field electroretinogram, optical coherence tomography, and fundus autofluorescence imaging), and neurofilament light chain (NfL) measurements. Here we report the baseline ophthalmic data from the cohort and determine whether there is a correlation between disease scores and ophthalmic results. Results Among the 15 included SCA7 carriers (median [range] age, 38 [18-60] years; 8 women and 7 men), 12 displayed cone or cone-rod dystrophy, with the number of CAG repeats correlating with disease severity (ρ, 0.73, 95% CI, 0.34 to 0.90; P < .001). Two patients with cone-rod dystrophy exhibited higher repeat numbers and greater ataxia scores (median [range] SARA score, 9 [7-15]) compared to those with only cone dystrophy (median [range] SARA score, 2 [0-5]). A correlation emerged for outer nuclear layer thickness with SARA score (ρ, -0.88; 95% CI, -0.96 to -0.59; P < .001) and NfL levels (ρ, -0.87; 95% CI, -0.86 to 0.96; P < .001). Moreover, ataxia severity was correlated with visual acuity (ρ: 0.89; 95% CI, 0.68 to 0.96; P < .001) and retinal sensitivity (ρ, -0.88; 95% CI, -0.96 to 0.59; P < .001). Conclusions and Relevance In this cross-sectional study, retinal abnormalities were found at preataxic stages of the disease. Most of the carriers presented with cone dystrophy and preserved rod function. The outer nuclear layer thickness correlated with SARA score and plasma NfL levels suggesting nuclear layer thickness to be a biomarker of disease severity. These findings contribute to understanding the dynamics of SCA7-related retinal dystrophy and may help lay the groundwork for future therapeutic intervention monitoring and clinical trials. Trial Registration ClinicalTrials.gov Identifier: NCT04288128.
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Affiliation(s)
- Marco Nassisi
- Sorbonne Université, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
| | - Giulia Coarelli
- Sorbonne Université, Institut du Cerveau, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Paris, France
- Assistance Publique – Hôpitaux de Paris, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Benoit Blanchard
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
| | - Charlotte Dubec-Fleury
- Sorbonne Université, Institut du Cerveau, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Paris, France
- Assistance Publique – Hôpitaux de Paris, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Karima Drine
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
| | - Nicolas Kitic
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
| | - Serge Sancho
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
| | - Rania Hilab
- Sorbonne Université, Institut du Cerveau, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Paris, France
- Assistance Publique – Hôpitaux de Paris, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Sophie Tezenas du Montcel
- Sorbonne Université, Institut du Cerveau, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Paris, France
- Assistance Publique – Hôpitaux de Paris, Hôpital de la Pitié Salpêtrière, Paris, France
| | | | - Roger Lane
- Ionis Pharmaceuticals, Carlsbad, California
| | | | - Alexandra Durr
- Sorbonne Université, Institut du Cerveau, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Paris, France
- Assistance Publique – Hôpitaux de Paris, Hôpital de la Pitié Salpêtrière, Paris, France
| | - Isabelle Audo
- Sorbonne Université, Institut national de la santé et de la recherche médicale, Centre national de la recherche scientifique, Institut de la Vision, Paris, France
- Centre Hospitalier National d’Ophtalmologie des Quinze-Vingts, National Rare Disease Center REFERET and Institut national de la santé et de la recherche médicale Directorate General of Health Care Provision, Centres d’Investigations Cliniques 1423, Paris, France
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Pilotto F, Del Bondio A, Puccio H. Hereditary Ataxias: From Bench to Clinic, Where Do We Stand? Cells 2024; 13:319. [PMID: 38391932 PMCID: PMC10886822 DOI: 10.3390/cells13040319] [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: 12/01/2023] [Revised: 01/30/2024] [Accepted: 02/01/2024] [Indexed: 02/24/2024] Open
Abstract
Cerebellar ataxias are a wide heterogeneous group of movement disorders. Within this broad umbrella of diseases, there are both genetics and sporadic forms. The clinical presentation of these conditions can exhibit a diverse range of symptoms across different age groups, spanning from pure cerebellar manifestations to sensory ataxia and multisystemic diseases. Over the last few decades, advancements in our understanding of genetics and molecular pathophysiology related to both dominant and recessive ataxias have propelled the field forward, paving the way for innovative therapeutic strategies aimed at preventing and arresting the progression of these diseases. Nevertheless, the rarity of certain forms of ataxia continues to pose challenges, leading to limited insights into the etiology of the disease and the identification of target pathways. Additionally, the lack of suitable models hampers efforts to comprehensively understand the molecular foundations of disease's pathophysiology and test novel therapeutic interventions. In the following review, we describe the epidemiology, symptomatology, and pathological progression of hereditary ataxia, including both the prevalent and less common forms of these diseases. Furthermore, we illustrate the diverse molecular pathways and therapeutic approaches currently undergoing investigation in both pre-clinical studies and clinical trials. Finally, we address the existing and anticipated challenges within this field, encompassing both basic research and clinical endeavors.
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Affiliation(s)
- Federica Pilotto
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Andrea Del Bondio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
| | - Hélène Puccio
- Institut Neuromyogène, Pathophysiology and Genetics of Neuron and Muscle, Inserm U1315, CNRS-Université Claude Bernard Lyon 1 UMR5261, 69008 Lyon, France
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Santos C, Malheiro S, Correia M, Damásio J. Gene Suppression Therapies in Hereditary Cerebellar Ataxias: A Systematic Review of Animal Studies. Cells 2023; 12:cells12071037. [PMID: 37048110 PMCID: PMC10093402 DOI: 10.3390/cells12071037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/27/2023] [Accepted: 03/28/2023] [Indexed: 03/30/2023] Open
Abstract
Introduction: Hereditary cerebellar ataxias (HCAs) are a heterogenous group of neurodegenerative disorders associated with severe disability. Treatment options are limited and overall restricted to symptomatic approaches, leading to poor prognoses. In recent years, there has been extensive research on gene suppression therapies (GSTs) as a new hope for disease-modifying strategies. In this article, we aim to perform a review of in vivo studies investigating the efficacy and safety profile of GSTs in HCAs. Methods: A structured PubMed® search on GSTs in HCAs from January 1993 up to October 2020 was performed. Inclusion and exclusion criteria were defined, and the selection process was conducted accordingly. The screening process was independently carried out by two authors and was initially based on title and abstract, followed by full-text reading. The risk-of-bias assessment was performed with SYRCLE’s tool. A data extraction sheet was created to collect relevant information from each selected article. Results: The initial search yielded 262 papers, of which 239 were excluded. An additional article was obtained following reference scrutiny, resulting in a total of 24 articles for final analysis. Most studies were not clear on the tools used to assess bias. In SCA1, SCA2, MJD/SCA3 and SCA7, RNA interference (iRNA) and antisense oligonucleotide (ASO) therapies proved to be well tolerated and effective in suppressing mutant proteins, improving neuropathological features and the motor phenotype. In SCA6, the phenotype was improved, but no investigation of adverse effects was performed. In FRDA, only the suppression efficacy of the electroporation of the clustered regularly interspaced short palindromic repeats associated with Cas9 enzyme system (CRISPR-Cas9) system was tested and confirmed. Conclusion: The literature reviewed suggests that GSTs are well tolerated and effective in suppressing the targeted proteins, improving neuropathological features and the motor phenotype in vivo. Nonetheless, there is no guarantee that these results are free of bias. Moreover, further investigation is still needed to clarify the GST effect on HCAs such as FRDA, SCA6 and SCA2.
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Vázquez-Mojena Y, León-Arcia K, González-Zaldivar Y, Rodríguez-Labrada R, Velázquez-Pérez L. Gene Therapy for Polyglutamine Spinocerebellar Ataxias: Advances, Challenges, and Perspectives. Mov Disord 2021; 36:2731-2744. [PMID: 34628681 DOI: 10.1002/mds.28819] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 09/02/2021] [Accepted: 09/06/2021] [Indexed: 12/11/2022] Open
Abstract
Polyglutamine spinocerebellar ataxias (SCAs) comprise a heterogeneous group of six autosomal dominant ataxias caused by cytosine-adenine-guanine repeat expansions in the coding region of single genes. Currently, there is no curative or disease-slowing treatment for these disorders, but their monogenic inheritance has informed rationales for development of gene therapy strategies. In fact, RNA interference strategies have shown promising findings in cellular and/or animal models of SCA1, SCA3, SCA6, and SCA7. In addition, antisense oligonucleotide therapy has provided encouraging proofs of concept in models of SCA1, SCA2, SCA3, and SCA7, but they have not yet progressed to clinical trials. On the contrary, the gene editing strategies, such as the clustered regularly interspaced short palindromic repeat (CRISPR/Cas9), have been introduced to a limited extent in these disorders. In this article, we review the available literature about gene therapy in polyglutamine SCAs and discuss the main technological and ethical challenges toward the prospect of their use in future clinical trials. Although antisense oligonucleotide therapies are further along the path to clinical phases, the recent failure of three clinical trials in Huntington's disease may delay their utilization for polyglutamine SCAs, but they offer lessons that could optimize the likelihood of success in potential future clinical studies. © 2021 International Parkinson and Movement Disorder Society.
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Borbolla-Jiménez FV, Del Prado-Audelo ML, Cisneros B, Caballero-Florán IH, Leyva-Gómez G, Magaña JJ. New Perspectives of Gene Therapy on Polyglutamine Spinocerebellar Ataxias: From Molecular Targets to Novel Nanovectors. Pharmaceutics 2021; 13:1018. [PMID: 34371710 PMCID: PMC8309146 DOI: 10.3390/pharmaceutics13071018] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/25/2021] [Accepted: 06/29/2021] [Indexed: 01/03/2023] Open
Abstract
Seven of the most frequent spinocerebellar ataxias (SCAs) are caused by a pathological expansion of a cytosine, adenine and guanine (CAG) trinucleotide repeat located in exonic regions of unrelated genes, which in turn leads to the synthesis of polyglutamine (polyQ) proteins. PolyQ proteins are prone to aggregate and form intracellular inclusions, which alter diverse cellular pathways, including transcriptional regulation, protein clearance, calcium homeostasis and apoptosis, ultimately leading to neurodegeneration. At present, treatment for SCAs is limited to symptomatic intervention, and there is no therapeutic approach to prevent or reverse disease progression. This review provides a compilation of the experimental advances obtained in cell-based and animal models toward the development of gene therapy strategies against polyQ SCAs, providing a discussion of their potential application in clinical trials. In the second part, we describe the promising potential of nanotechnology developments to treat polyQ SCA diseases. We describe, in detail, how the design of nanoparticle (NP) systems with different physicochemical and functionalization characteristics has been approached, in order to determine their ability to evade the immune system response and to enhance brain delivery of molecular tools. In the final part of this review, the imminent application of NP-based strategies in clinical trials for the treatment of polyQ SCA diseases is discussed.
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Affiliation(s)
- Fabiola V. Borbolla-Jiménez
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Programa de Ciencias Biomédicas, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico
| | - María Luisa Del Prado-Audelo
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
| | - Bulmaro Cisneros
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico;
| | - Isaac H. Caballero-Florán
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
- Departamento de Farmacia, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV), Ciudad de México 07360, Mexico
| | - Gerardo Leyva-Gómez
- Departamento de Farmacia, Facultad de Química, Universidad Nacional Autónoma de México, Ciudad de México 04510, Mexico;
| | - Jonathan J. Magaña
- Laboratorio de Medicina Genómica, Departamento de Genética, Instituto Nacional de Rehabilitación-Luis Guillermo Ibarra Ibarra, Ciudad de México 14389, Mexico;
- Departamento de Bioingeniería, Escuela de Ingeniería y Ciencias, Tecnológico de Monterrey Campus Ciudad de México, Ciudad de México 14380, Mexico;
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AlHilali S, AlMadhi NH, AlBalawi ED. Ophthalmic Features of Spinocerebellar Ataxia Type 7: A Case Report. AMERICAN JOURNAL OF CASE REPORTS 2021; 22:e932279. [PMID: 34148052 PMCID: PMC8235670 DOI: 10.12659/ajcr.932279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Patient: Male, 32-year-old Final Diagnosis: Spinocerebellar ataxia Symptoms: Ataxia • decrease in the visual acuity Medication: — Clinical Procedure: — Specialty: Ophthalmology
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Affiliation(s)
- Sara AlHilali
- Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Nada H AlMadhi
- Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | - Eman D AlBalawi
- Department of Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
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Current Status of Gene Therapy Research in Polyglutamine Spinocerebellar Ataxias. Int J Mol Sci 2021; 22:ijms22084249. [PMID: 33921915 PMCID: PMC8074016 DOI: 10.3390/ijms22084249] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 04/14/2021] [Accepted: 04/14/2021] [Indexed: 12/26/2022] Open
Abstract
Polyglutamine spinocerebellar ataxias (PolyQ SCAs) are a group of 6 rare autosomal dominant diseases, which arise from an abnormal CAG repeat expansion in the coding region of their causative gene. These neurodegenerative ataxic disorders are characterized by progressive cerebellar degeneration, which translates into progressive ataxia, the main clinical feature, often accompanied by oculomotor deficits and dysarthria. Currently, PolyQ SCAs treatment is limited only to symptomatic mitigation, and no therapy is available to stop or delay the disease progression, which culminates with death. Over the last years, many promising gene therapy approaches were investigated in preclinical studies and could lead to a future treatment to stop or delay the disease development. Here, we summed up the most promising of these therapies, categorizing them in gene augmentation therapy, gene silencing strategies, and gene edition approaches. While several of the reviewed strategies are promising, there is still a gap from the preclinical results obtained and their translation to clinical studies. However, there is an increase in the number of approved gene therapies, as well as a constant development in their safety and efficacy profiles. Thus, it is expected that in a near future some of the promising strategies reviewed here could be tested in a clinical setting and if successful provide hope for SCAs patients.
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Kotowska-Zimmer A, Pewinska M, Olejniczak M. Artificial miRNAs as therapeutic tools: Challenges and opportunities. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1640. [PMID: 33386705 DOI: 10.1002/wrna.1640] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 12/21/2022]
Abstract
RNA interference (RNAi) technology has been used for almost two decades to study gene functions and in therapeutic approaches. It uses cellular machinery and small, designed RNAs in the form of synthetic small interfering RNAs (siRNAs) or vector-based short hairpin RNAs (shRNAs), and artificial miRNAs (amiRNAs) to inhibit a gene of interest. Artificial miRNAs, known also as miRNA mimics, shRNA-miRs, or pri-miRNA-like shRNAs have the most complex structures and undergo two-step processing in cells to form mature siRNAs, which are RNAi effectors. AmiRNAs are composed of a target-specific siRNA insert and scaffold based on a natural primary miRNA (pri-miRNA). siRNAs serve as a guide to search for complementary sequences in transcripts, whereas pri-miRNA scaffolds ensure proper processing and transport. The dynamics of siRNA maturation and siRNA levels in the cell resemble those of endogenous miRNAs; therefore amiRNAs are safer than other RNAi triggers. Delivered as viral vectors and expressed under tissue-specific polymerase II (Pol II) promoters, amiRNAs provide long-lasting silencing and expression in selected tissues. Therefore, amiRNAs are useful therapeutic tools for a broad spectrum of human diseases, including neurodegenerative diseases, cancers and viral infections. Recent reports on the role of sequence and structure in pri-miRNA processing may contribute to the improvement of the amiRNA tools. In addition, the success of a recently initiated clinical trial for Huntington's disease could pave the way for other amiRNA-based therapies, if proven effective and safe. This article is categorized under: RNA Processing > Processing of Small RNAs Regulatory RNAs/RNAi/Riboswitches > RNAi: Mechanisms of Action RNA in Disease and Development > RNA in Disease.
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Affiliation(s)
- Anna Kotowska-Zimmer
- Department of Genome Engineering, Institute of Bioorganic Chemistry PAS, Poznan, Poland
| | - Marianna Pewinska
- Department of Genome Engineering, Institute of Bioorganic Chemistry PAS, Poznan, Poland
| | - Marta Olejniczak
- Department of Genome Engineering, Institute of Bioorganic Chemistry PAS, Poznan, Poland
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Marianelli BF, Filho FMR, Salles MV, de Andrade JBC, Pedroso JL, Sallum JMF, Barsottini OGP. A Proposal for Classification of Retinal Degeneration in Spinocerebellar Ataxia Type 7. THE CEREBELLUM 2020; 20:384-391. [PMID: 33196954 DOI: 10.1007/s12311-020-01215-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/09/2020] [Indexed: 12/17/2022]
Abstract
The aim of this study is to propose a classification system for the spinocerebellar ataxia type 7 retinal degeneration (SCA7-RD). Twenty patients with molecularly confirmed SCA7 underwent slit lamp examination, fundus photography, and optical coherence tomography (Spectralis®). Scale for the Assessment and Rating of Ataxia (SARA) and International Cooperative Ataxia Rating Scale (ICARS) were applied, and age, sex, age at symptom onset, and number of CAG expansions were recorded. After analyzing the ophthalmological findings in each participant, a panel of retinal disease experts created a qualitative classification system for SCA7-RD comprising four stages. We assessed the correlations of retinal degeneration severity with SARA and ICARS scores, number of CAG repeats in ATXN7 allele, and age at symptom onset. We graded retinal degeneration as stage 1 in nine participants, as stage 2 in five, and as stage 3 in six. No differences in age and visual symptoms duration were found between groups. SARA and ICARS scores correlated with the severity of SCA7-RD on the classification system (p = 0.024 and p = 0.014, respectively). After adjusting for disease duration, retinal disease stage association with SARA and ICARS scores remained significant (ANCOVA, p < 0.05). The classification system for SCA7-RD was able to characterize different disease stages representing the landmarks in the cone-rod dystrophy natural history. Neurodegeneration appears to occur in parallel in the cerebellum and in the visual pathway. We conclude that retinal degeneration in SCA7 is a potential biomarker of the neurological phenotype severity.
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Affiliation(s)
- Bruna Ferraço Marianelli
- Division of Retina and Vitreous, Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, SP, Brazil. .,, Vitória, Brazil.
| | - Flávio Moura Rezende Filho
- Division of General Neurology and Ataxia Unit, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Mariana Vallim Salles
- Division of Retina and Vitreous, Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - João Brainer Clares de Andrade
- Division of General Neurology and Ataxia Unit, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - José Luiz Pedroso
- Division of General Neurology and Ataxia Unit, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Juliana Maria Ferraz Sallum
- Division of Retina and Vitreous, Department of Ophthalmology, Universidade Federal de São Paulo, São Paulo, SP, Brazil
| | - Orlando Graziani P Barsottini
- Division of General Neurology and Ataxia Unit, Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, São Paulo, SP, Brazil
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Neves-Carvalho A, Duarte-Silva S, Teixeira-Castro A, Maciel P. Polyglutamine spinocerebellar ataxias: emerging therapeutic targets. Expert Opin Ther Targets 2020; 24:1099-1119. [PMID: 32962458 DOI: 10.1080/14728222.2020.1827394] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Six of the most frequent dominantly inherited spinocerebellar ataxias (SCAs) worldwide - SCA1, SCA2, SCA3, SCA6, SCA7, and SCA17 - are caused by an expansion of a polyglutamine (polyQ) tract in the corresponding proteins. While the identification of the causative mutation has advanced knowledge on the pathogenesis of polyQ SCAs, effective therapeutics able to mitigate the severe clinical manifestation of these highly incapacitating disorders are not yet available. AREAS COVERED This review provides a comprehensive and critical perspective on well-established and emerging therapeutic targets for polyQ SCAs; it aims to inspire prospective drug discovery efforts. EXPERT OPINION The landscape of polyQ SCAs therapeutic targets and strategies includes (1) the mutant genes and proteins themselves, (2) enhancement of endogenous protein quality control responses, (3) abnormal protein-protein interactions of the mutant proteins, (4) disturbed neuronal function, (5) mitochondrial function, energy availability and oxidative stress, and (6) glial dysfunction, growth factor or hormone imbalances. Challenges include gaining a clearer definition of therapeutic targets for the drugs in clinical development, the discovery of novel drug-like molecules for challenging key targets, and the attainment of a stronger translation of preclinical findings to the clinic.
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Affiliation(s)
- Andreia Neves-Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Andreia Teixeira-Castro
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho , Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory , Braga, Guimarães, Portugal
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Park JY, Joo K, Woo SJ. Ophthalmic Manifestations and Genetics of the Polyglutamine Autosomal Dominant Spinocerebellar Ataxias: A Review. Front Neurosci 2020; 14:892. [PMID: 32973440 PMCID: PMC7472957 DOI: 10.3389/fnins.2020.00892] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/30/2020] [Indexed: 12/20/2022] Open
Abstract
Spinocerebellar ataxia (SCA) is a part of the cerebellar neurodegenerative disease group that is diverse in genetics and phenotypes. It usually shows autosomal dominant inheritance. SCAs, always together with the cerebellar degeneration, may exhibit clinical deficits in brainstem or eye, especially retina or optic nerve. Interestingly, autosomal dominant SCAs share a common genetic mechanism; the length of the glutamine chain is abnormally expanded due to the increase in the cytosine–adenine–guanine (CAG) repeats of the disease causing gene. Studies have suggested that the mutant ataxin induces alteration of protein conformation and abnormal aggregation resulting in nuclear inclusions, and causes cellular loss of photoreceptors through a toxic effect. As a result, these pathologic changes induce a downregulation of genes involved in the phototransduction, development, and differentiation of photoreceptors such as CRX, one of the photoreceptor transcription factors. However, the exact mechanism of neuronal degeneration by mutant ataxin restricted to only certain type of neuronal cell including cerebellar Purkinje neurons and photoreceptor is still unclear. The most common SCAs are types 1, 2, 3, 6, 7, and 17 which contain about 80% of autosomal dominant SCA cases. Various aspects of eye movement abnormalities are evident depending on the degree of cerebellar and brainstem degeneration in SCAs. In addition, certain types of SCAs such as SCA7 are characterized by both cerebellar ataxia and visual loss mainly due to retinal degeneration. The severity of the retinopathy can vary from occult macular photoreceptor disruption to extensive retinal atrophy and is correlated with the number of CAG repeats. The value of using optical coherence tomography in conjunction with electrodiagnostic and genetic testing is emphasized as the combination of these tests can provide critical information regarding the etiology, morphological evaluation, and functional significances. Therefore, ophthalmologists need to recognize and differentiate SCAs in order to properly diagnose and evaluate the disease. In this review, we have described and discussed SCAs showing ophthalmic abnormalities with particular attention to their ophthalmic features, neurodegenerative mechanisms, genetics, and future perspectives.
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Affiliation(s)
- Jun Young Park
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Kwangsic Joo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, South Korea
| | - Se Joon Woo
- Department of Ophthalmology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, South Korea
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12
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Recent Advances in the Treatment of Cerebellar Disorders. Brain Sci 2019; 10:brainsci10010011. [PMID: 31878024 PMCID: PMC7017280 DOI: 10.3390/brainsci10010011] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 12/13/2019] [Accepted: 12/20/2019] [Indexed: 12/19/2022] Open
Abstract
Various etiopathologies affect the cerebellum, resulting in the development of cerebellar ataxias (CAs), a heterogeneous group of disorders characterized clinically by movement incoordination, affective dysregulation, and cognitive dysmetria. Recent progress in clinical and basic research has opened the door of the ‘‘era of therapy” of CAs. The therapeutic rationale of cerebellar diseases takes into account the capacity of the cerebellum to compensate for pathology and restoration, which is collectively termed cerebellar reserve. In general, treatments of CAs are classified into two categories: cause-cure treatments, aimed at arresting disease progression, and neuromodulation therapies, aimed at potentiating cerebellar reserve. Both forms of therapies should be introduced as soon as possible, at a time where cerebellar reserve is still preserved. Clinical studies have established evidence-based cause-cure treatments for metabolic and immune-mediated CAs. Elaborate protocols of rehabilitation and non-invasive cerebellar stimulation facilitate cerebellar reserve, leading to recovery in the case of controllable pathologies (metabolic and immune-mediated CAs) and delay of disease progression in the case of uncontrollable pathologies (degenerative CAs). Furthermore, recent advances in molecular biology have encouraged the development of new forms of therapies: the molecular targeting therapy, which manipulates impaired RNA or proteins, and the neurotransplantation therapy, which delays cell degeneration and facilitates compensatory functions. The present review focuses on the therapeutic rationales of these recently developed therapeutic modalities, highlighting the underlying pathogenesis.
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13
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Azevedo PB, Rocha AG, Keim LMN, Lavinsky D, Furtado GV, de Mattos EP, Vargas FR, Leotti VB, Saraiva-Pereira ML, Jardim LB. Ophthalmological and Neurologic Manifestations in Pre-clinical and Clinical Phases of Spinocerebellar Ataxia Type 7. THE CEREBELLUM 2019; 18:388-396. [PMID: 30637674 DOI: 10.1007/s12311-019-1004-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Spinocerebellar ataxia type 7 (SCA7) is a polyglutamine disease that progressively affects the cerebellum, brainstem, and retina. SCA7 is quite rare, and insights into biomarkers and pre-clinical phases are still missing. We aimed to describe neurologic and ophthalmological findings observed in symptomatic and pre-symptomatic SCA7 subjects. Several neurologic scales, visual acuity, visual fields obtained by computer perimetry, and macular thickness in optical coherence tomography (mOCT) were measured in symptomatic carriers and at risk relatives. Molecular analysis of the ATXN7 was done blindly in individuals at risk. Thirteen symptomatic carriers, 3 pre-symptomatic subjects, and 5 related controls were enrolled. Symptomatic carriers presented scores significantly different from those of controls in most neurologic and ophthalmological scores. Gradual changes from controls to pre-symptomatic and then to symptomatic carriers were seen in mean (SD) of visual fields - 1.34 (1.15), - 2.81 (1.66). and - 9.56 (7.26); mOCT - 1.11 (2.6), - 3.48 (3.54), and - 7.73 (2.56) Z scores; and "Spinocerebellar Ataxia Functional Index (SCAFI)" - 1.16 (0.28), 0.65 (0.56), and - 0.61 (0.44), respectively. Visual fields and SCAFI were significantly correlated with time to disease onset (pre-symptomatic)/disease duration (symptomatic carriers). Visual fields, mOCT, and SCAFI stood out as candidates for state biomarkers for SCA7 since pre-symptomatic stages of disease.
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Affiliation(s)
- Pietro B Azevedo
- Programa de Pós-Graduação em Ciências Médicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Serviço de Oftalmologia, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Anastácia G Rocha
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Leda M N Keim
- Hospital Gaffrée e Guinle, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Daniel Lavinsky
- Serviço de Oftalmologia, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Departamento de Oftalmologia e Otorrinolaringologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
| | - Gabriel V Furtado
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratório de Investigação Genética, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Eduardo P de Mattos
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratório de Investigação Genética, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Fernando R Vargas
- Hospital Gaffrée e Guinle, Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, Brazil
- Laboratório de Epidemiologia de Malformações Congênitas, Fundação Oswaldo Cruz, Instituto Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Vanessa B Leotti
- Departamento de Estatística, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Maria-Luiza Saraiva-Pereira
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Laboratório de Investigação Genética, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
- Departamento de Bioquímica, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
- Serviço de Genética Médica, Hospital de Clínicas de Porto Alegre, Porto Alegre, Brazil
| | - Laura B Jardim
- Programa de Pós-Graduação em Ciências Médicas, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
- Faculdade de Medicina, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
- Programa de Pós-Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
- Laboratório de Investigação Genética, Hospital de Clínicas de Porto Alegre, 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.
- Medical Genetics Service, Hospital de Clínicas de Porto Alegre, Rua Ramiro Barcelos 2350, Porto Alegre, 90035-003, Brazil.
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Cendelin J, Buffo A, Hirai H, Magrassi L, Mitoma H, Sherrard R, Vozeh F, Manto M. Task Force Paper On Cerebellar Transplantation: Are We Ready to Treat Cerebellar Disorders with Cell Therapy? THE CEREBELLUM 2019; 18:575-592. [PMID: 30607797 DOI: 10.1007/s12311-018-0999-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Restoration of damaged central nervous system structures, functional recovery, and prevention of neuronal loss during neurodegenerative diseases are major objectives in cerebellar research. The highly organized anatomical structure of the cerebellum with numerous inputs/outputs, the complexity of cerebellar functions, and the large spectrum of cerebellar ataxias render therapies of cerebellar disorders highly challenging. There are currently several therapeutic approaches including motor rehabilitation, neuroprotective drugs, non-invasive cerebellar stimulation, molecularly based therapy targeting pathogenesis of the disease, and neurotransplantation. We discuss the goals and possible beneficial mechanisms of transplantation therapy for cerebellar damage and its limitations and factors determining outcome.
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Affiliation(s)
- Jan Cendelin
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 1655/76, 323 00, Plzen, Czech Republic
- Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 1655/76, 323 00, Plzen, Czech Republic
| | - Annalisa Buffo
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, 10126, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Orbassano, 10043, Turin, Italy
| | - Hirokazu Hirai
- Department of Neurophysiology and Neural Repair, Gunma University Graduate School of Medicine, 3-39-22, Maebashi, Gunma, 371-8511, Japan
| | - Lorenzo Magrassi
- Neurosurgery, Dipartimento di Scienze Clinico-Chirurgiche Diagnostiche e Pediatriche, Fondazione IRCCS Policlinico S. Matteo, Università degli Studi di Pavia, 27100, Pavia, Italy
- Istituto di Genetica Molecolare - CNR, 27100, Pavia, Italy
| | - Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan
| | - Rachel Sherrard
- IBPS, UMR8256 Biological Adaptation and Ageing, Sorbonne Université and CNRS, Paris, France
| | - Frantisek Vozeh
- Department of Pathophysiology, Faculty of Medicine in Pilsen, Charles University, alej Svobody 1655/76, 323 00, Plzen, Czech Republic
- Laboratory of Neurodegenerative Disorders, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, alej Svobody 1655/76, 323 00, Plzen, Czech Republic
| | - Mario Manto
- Department of Neurology, CHU-Charleroi, 6000, Charleroi, Belgium.
- Service des Neurosciences, Université de Mons, 7000, Mons, Belgium.
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15
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Abstract
The spinocerebellar ataxias (SCAs) comprise more than 40 autosomal dominant neurodegenerative disorders that present principally with progressive ataxia. Within the past few years, studies of pathogenic mechanisms in the SCAs have led to the development of promising therapeutic strategies, especially for SCAs caused by polyglutamine-coding CAG repeats. Nucleotide-based gene-silencing approaches that target the first steps in the pathogenic cascade are one promising approach not only for polyglutamine SCAs but also for the many other SCAs caused by toxic mutant proteins or RNA. For these and other emerging therapeutic strategies, well-coordinated preparation is needed for fruitful clinical trials. To accomplish this goal, investigators from the United States and Europe are now collaborating to share data from their respective SCA cohorts. Increased knowledge of the natural history of SCAs, including of the premanifest and early symptomatic stages of disease, will improve the prospects for success in clinical trials of disease-modifying drugs. In addition, investigators are seeking validated clinical outcome measures that demonstrate responsiveness to changes in SCA populations. Findings suggest that MRI and magnetic resonance spectroscopy biomarkers will provide objective biological readouts of disease activity and progression, but more work is needed to establish disease-specific biomarkers that track target engagement in therapeutic trials. Together, these efforts suggest that the development of successful therapies for one or more SCAs is not far away.
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16
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Dong X, Cong S. The Emerging Role of microRNAs in Polyglutamine Diseases. Front Mol Neurosci 2019; 12:156. [PMID: 31275113 PMCID: PMC6593396 DOI: 10.3389/fnmol.2019.00156] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 06/04/2019] [Indexed: 12/21/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding molecules that regulate a large amount of post-transcriptional repressor genes by recognizing semi-complementary target sequences that are normally located in the 3' UTR of the mRNA. Altered expression of miRNA has been related to several pathological processes, including polyglutamine (Poly Q) diseases. Specific expression patterns in the circulating fluids and brain parenchyma have been speculated as potential biomarkers for Poly Q disease diagnosis and prognosis. Several miRNAs have been consistently identified in diseases including Huntington's disease (HD) and spinocerebellar ataxia (SCA). In our review, we describe the emerging role of miRNAs in Poly Q diseases and provide an overview on general miRNA biology, implications in pathophysiology, and their potential roles as future biomarkers and applications for therapy.
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Affiliation(s)
| | - Shuyan Cong
- Department of Neurology, Shengjing Hospital of China Medical University, Shenyang, China
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17
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Buijsen RAM, Toonen LJA, Gardiner SL, van Roon-Mom WMC. Genetics, Mechanisms, and Therapeutic Progress in Polyglutamine Spinocerebellar Ataxias. Neurotherapeutics 2019; 16:263-286. [PMID: 30607747 PMCID: PMC6554265 DOI: 10.1007/s13311-018-00696-y] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Autosomal dominant cerebellar ataxias (ADCAs) are a group of neurodegenerative disorders characterized by degeneration of the cerebellum and its connections. All ADCAs have progressive ataxia as their main clinical feature, frequently accompanied by dysarthria and oculomotor deficits. The most common spinocerebellar ataxias (SCAs) are 6 polyglutamine (polyQ) SCAs. These diseases are all caused by a CAG repeat expansion in the coding region of a gene. Currently, no curative treatment is available for any of the polyQ SCAs, but increasing knowledge on the genetics and the pathological mechanisms of these polyQ SCAs has provided promising therapeutic targets to potentially slow disease progression. Potential treatments can be divided into pharmacological and gene therapies that target the toxic downstream effects, gene therapies that target the polyQ SCA genes, and stem cell replacement therapies. Here, we will provide a review on the genetics, mechanisms, and therapeutic progress in polyglutamine spinocerebellar ataxias.
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Affiliation(s)
- Ronald A M Buijsen
- Department of Human Genetics, LUMC, P.O. Box 9600, 2300 RC, Leiden, The Netherlands.
| | - Lodewijk J A Toonen
- Department of Human Genetics, LUMC, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
| | - Sarah L Gardiner
- Department of Human Genetics, LUMC, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
- Department of Neurology, LUMC, P.O. Box 9600, 2300 RC, Leiden, The Netherlands
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18
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Abstract
The cerebellum characteristically has the capacity to compensate for and restore lost functions. These compensatory/restorative properties are explained by an abundant synaptic plasticity and the convergence of multimodal central and peripheral signals. In addition, extra-cerebellar structures contribute also to the recovery after a cerebellar injury. Clinically, some patients show remarkable improvement of severe ataxic symptoms associated with trauma, stroke, metabolism, or immune-mediated cerebellar ataxia (IMCA, e.g., multiple sclerosis, paraneoplastic cerebellar degeneration, gluten ataxia, anti-GAD65 antibody-associated cerebellar ataxia). However, extension of a cerebellar lesion can impact upon the fourth ventricle or the brainstem, either by direct or indirect mechanisms, leading to serious complications. Moreover, cerebellar reserve itself is affected by advanced cell loss and, at some point of disease progression, deficits become irreversible. Such phase transition from a treatable/restorable state (the reserve is still sufficient) to an untreatable state (the reserve is severely affected) is a loss of therapeutic opportunity, highlighting the need for early treatment during the restorable stage. Based on the motto of "Time is Brain," a warning that stresses the importance of early therapeutic intervention in ischemic diseases, we propose "Time is Cerebellum" as a principle in the management of patients with cerebellar diseases, especially immune ataxias whose complexity often delay the therapeutic intervention. Indeed, this concept should not be restricted to ischemic cerebellar diseases. We argue that every effort should be made to reduce the diagnostic delay and to initiate early therapy to avoid the risk of transition from a treatable state to an irreversible condition and an associated accumulation of disability. The myriad of disorders affecting the cerebellum is a challenging factor that may contribute to irreversible disability if the window of therapeutic opportunity is missed.
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Affiliation(s)
- Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan.
| | - Mario Manto
- Unité d'Etude du Mouvement (UEM), FNRS, ULB-Erasme, 1070, Bruxelles, Belgium
- Service des Neurosciences, University of Mons, 7000, Mons, Belgium
- Department of Neurology, Centre Hospitalier Universitaire (CHU) de Charleroi, 6000, Charleroi, Belgium
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19
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Duncan JL, Pierce EA, Laster AM, Daiger SP, Birch DG, Ash JD, Iannaccone A, Flannery JG, Sahel JA, Zack DJ, Zarbin MA. Inherited Retinal Degenerations: Current Landscape and Knowledge Gaps. Transl Vis Sci Technol 2018; 7:6. [PMID: 30034950 PMCID: PMC6052953 DOI: 10.1167/tvst.7.4.6] [Citation(s) in RCA: 133] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 05/28/2018] [Indexed: 12/11/2022] Open
Affiliation(s)
- Jacque L Duncan
- Department of Ophthalmology, University of California, San Francisco, San Francisco, CA, USA
| | - Eric A Pierce
- Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, USA
| | - Amy M Laster
- Foundation Fighting Blindness, Columbia, MD, USA
| | - Stephen P Daiger
- Human Genetics Center, School of Public Health, and Ruiz Department of Ophthalmology and Visual Science, The University of Texas Health Science Center, Houston, TX, USA
| | - David G Birch
- Rose-Silverthorne Retinal Degenerations Laboratory, Retina Foundation of the Southwest, Dallas, TX, USA
| | - John D Ash
- Department of Ophthalmology, University of Florida, Gainesville, FL, USA
| | - Alessandro Iannaccone
- Center for Retinal Degenerations and Ophthalmic Genetic Diseases, Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - John G Flannery
- Vision Science, the Helen Wills Neuroscience Institute, the Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - José A Sahel
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.,Institut de la Vision-Sorbonne Université, Inserm, CNRS-Paris, France
| | - Donald J Zack
- Departments of Ophthalmology, Neuroscience, Molecular Biology and Genetics, and Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Marco A Zarbin
- Institute of Ophthalmology and Visual Science, Rutgers-New Jersey Medical School, Rutgers University, Newark, NJ, USA
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20
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Abstract
Polyglutamine diseases are hereditary degenerative disorders of the nervous system that have remained, to this date, untreatable. Promisingly, investigation into their molecular etiology and the development of increasingly perfected tools have contributed to the design of novel strategies with therapeutic potential. Encouraging studies have explored gene therapy as a means to counteract cell demise and loss in this context. The current chapter addresses the two main focuses of research in the area: the characteristics of the systems used to deliver nucleic acids to cells and the molecular and cellular actions of the therapeutic agents. Vectors used in gene therapy have to satisfyingly reach the tissues and cell types of interest, while eliciting the lowest toxicity possible. Both viral and non-viral systems have been developed for the delivery of nucleic acids to the central nervous system, each with its respective advantages and shortcomings. Since each polyglutamine disease is caused by mutation of a single gene, many gene therapy strategies have tried to halt degeneration by silencing the corresponding protein products, usually recurring to RNA interference. The potential of small interfering RNAs, short hairpin RNAs and microRNAs has been investigated. Overexpression of protective genes has also been evaluated as a means of decreasing mutant protein toxicity and operate beneficial alterations. Recent gene editing tools promise yet other ways of interfering with the disease-causing genes, at the most upstream points possible. Results obtained in both cell and animal models encourage further delving into this type of therapeutic strategies and support the future use of gene therapy in the treatment of polyglutamine diseases.
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21
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Abstract
Spinocerebellar ataxias (SCAs) are a genetically diverse group of dominantly inherited disorders that share clinical features that result from dysfunction and degeneration of the cerebellum and its associated pathways. Although nearly 40 genes are currently recognized to result in SCA, shared mechanisms for disease pathogenesis exist among subsets of the SCAs. The most common SCAs result from a glutamine-encoding CAG repeat in the respective disease genes. This chapter discusses the varied genetic etiology of SCA and attempts to categorize these disorders based on shared mechanisms of disease. We also summarize evaluation and management for the SCAs.
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Affiliation(s)
- Andrew Mundwiler
- Department of Neurosciences, Spectrum Health, Grand Rapids, MI, United States; College of Human Medicine, Michigan State University, Grand Rapids, MI, United States
| | - Vikram G Shakkottai
- Department of Neurology, University of Michigan, Ann Arbor, MI, United States.
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22
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Curtis HJ, Seow Y, Wood MJA, Varela MA. Knockdown and replacement therapy mediated by artificial mirtrons in spinocerebellar ataxia 7. Nucleic Acids Res 2017; 45:7870-7885. [PMID: 28575281 PMCID: PMC5569705 DOI: 10.1093/nar/gkx483] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 05/26/2017] [Indexed: 12/13/2022] Open
Abstract
We evaluate a knockdown-replacement strategy mediated by mirtrons as an alternative to allele-specific silencing using spinocerebellar ataxia 7 (SCA7) as a model. Mirtrons are introns that form pre-microRNA hairpins after splicing, producing RNAi effectors not processed by Drosha. Mirtron mimics may therefore avoid saturation of the canonical processing pathway. This method combines gene silencing mediated by an artificial mirtron with delivery of a functional copy of the gene such that both elements of the therapy are always expressed concurrently, minimizing the potential for undesirable effects and preserving wild-type function. This mutation- and single nucleotide polymorphism-independent method could be crucial in dominant diseases that feature both gain- and loss-of-function pathologies or have a heterogeneous genetic background. Here we develop mirtrons against ataxin 7 with silencing efficacy comparable to shRNAs, and introduce silent mutations into an ataxin 7 transgene such that it is resistant to their effect. We successfully express the transgene and one mirtron together from a single construct. Hence, we show that this method can be used to silence the endogenous allele of ataxin 7 and replace it with an exogenous copy of the gene, highlighting the efficacy and transferability across patient genotypes of this approach.
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Affiliation(s)
- Helen J Curtis
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK.,Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford OX2 6GG, UK
| | - Yiqi Seow
- Molecular Engineering Laboratory, Biomedical Sciences Institutes, A*STAR, Singapore
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Miguel A Varela
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
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23
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Fiszer A, Wroblewska JP, Nowak BM, Krzyzosiak WJ. Mutant CAG Repeats Effectively Targeted by RNA Interference in SCA7 Cells. Genes (Basel) 2016; 7:genes7120132. [PMID: 27999335 PMCID: PMC5192508 DOI: 10.3390/genes7120132] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 12/06/2016] [Accepted: 12/09/2016] [Indexed: 02/08/2023] Open
Abstract
Spinocerebellar ataxia type 7 (SCA7) is a human neurodegenerative polyglutamine (polyQ) disease caused by a CAG repeat expansion in the open reading frame of the ATXN7 gene. The allele-selective silencing of mutant transcripts using a repeat-targeting strategy has previously been used for several polyQ diseases. Herein, we demonstrate that the selective targeting of a repeat tract in a mutant ATXN7 transcript by RNA interference is a feasible approach and results in an efficient decrease of mutant ataxin-7 protein in patient-derived cells. Oligonucleotides (ONs) containing specific base substitutions cause the downregulation of the ATXN7 mutant allele together with the upregulation of its normal allele. The A2 ON shows high allele selectivity at a broad range of concentrations and also restores UCHL1 expression, which is downregulated in SCA7.
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Affiliation(s)
- Agnieszka Fiszer
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
| | - Joanna P Wroblewska
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
| | - Bartosz M Nowak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14 Str., 61-704 Poznan, Poland.
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24
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Esteves S, Duarte-Silva S, Maciel P. Discovery of Therapeutic Approaches for Polyglutamine Diseases: A Summary of Recent Efforts. Med Res Rev 2016; 37:860-906. [PMID: 27870126 DOI: 10.1002/med.21425] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Revised: 10/01/2016] [Accepted: 10/05/2016] [Indexed: 12/19/2022]
Abstract
Polyglutamine (PolyQ) diseases are a group of neurodegenerative disorders caused by the expansion of cytosine-adenine-guanine (CAG) trinucleotide repeats in the coding region of specific genes. This leads to the production of pathogenic proteins containing critically expanded tracts of glutamines. Although polyQ diseases are individually rare, the fact that these nine diseases are irreversibly progressive over 10 to 30 years, severely impairing and ultimately fatal, usually implicating the full-time patient support by a caregiver for long time periods, makes their economic and social impact quite significant. This has led several researchers worldwide to investigate the pathogenic mechanism(s) and therapeutic strategies for polyQ diseases. Although research in the field has grown notably in the last decades, we are still far from having an effective treatment to offer patients, and the decision of which compounds should be translated to the clinics may be very challenging. In this review, we provide a comprehensive and critical overview of the most recent drug discovery efforts in the field of polyQ diseases, including the most relevant findings emerging from two different types of approaches-hypothesis-based candidate molecule testing and hypothesis-free unbiased drug screenings. We hereby summarize and reflect on the preclinical studies as well as all the clinical trials performed to date, aiming to provide a useful framework for increasingly successful future drug discovery and development efforts.
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Affiliation(s)
- Sofia Esteves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal.,ICVS/3B's PT Government Associate Laboratory, University of Minho, Guimarães, Braga, Portugal
| | - Sara Duarte-Silva
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal.,ICVS/3B's PT Government Associate Laboratory, University of Minho, Guimarães, Braga, Portugal
| | - Patrícia Maciel
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057, Braga, Portugal.,ICVS/3B's PT Government Associate Laboratory, University of Minho, Guimarães, Braga, Portugal
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Wagner JL, O'Connor DM, Donsante A, Boulis NM. Gene, Stem Cell, and Alternative Therapies for SCA 1. Front Mol Neurosci 2016; 9:67. [PMID: 27570504 PMCID: PMC4981596 DOI: 10.3389/fnmol.2016.00067] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Accepted: 07/26/2016] [Indexed: 12/26/2022] Open
Abstract
Spinocerebellar ataxia 1 is an autosomal dominant disease characterized by neurodegeneration and motor dysfunction. In disease pathogenesis, polyglutamine expansion within Ataxin-1, a gene involved in transcriptional repression, causes protein nuclear inclusions to form. Most notably, neuronal dysfunction presents in Purkinje cells. However, the effect of mutant Ataxin-1 is not entirely understood. Two mouse models are employed to represent spinocerebellar ataxia 1, a B05 transgenic model that specifically expresses mutant Ataxin-1 in Purkinje cells, and a Sca1 154Q/2Q model that inserts the polyglutamine expansion into the mouse Ataxin-1 locus so that the mutant Ataxin-1 is expressed in all cells that express Ataxin-1. This review aims to summarize and evaluate the wide variety of therapies proposed for spinocerebellar ataxia 1, specifically gene and stem cell therapies.
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Affiliation(s)
- Jacob L Wagner
- Boulis Laboratory, Department of Neurosurgery, Emory School of Medicine Atlanta, GA, USA
| | - Deirdre M O'Connor
- Boulis Laboratory, Department of Neurosurgery, Emory School of Medicine Atlanta, GA, USA
| | - Anthony Donsante
- Boulis Laboratory, Department of Neurosurgery, Emory School of Medicine Atlanta, GA, USA
| | - Nicholas M Boulis
- Boulis Laboratory, Department of Neurosurgery, Emory School of Medicine Atlanta, GA, USA
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Keiser MS, Kordasiewicz HB, McBride JL. Gene suppression strategies for dominantly inherited neurodegenerative diseases: lessons from Huntington's disease and spinocerebellar ataxia. Hum Mol Genet 2016; 25:R53-64. [PMID: 26503961 PMCID: PMC4802374 DOI: 10.1093/hmg/ddv442] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 10/17/2015] [Indexed: 12/17/2022] Open
Abstract
RNA-targeting approaches are emerging as viable therapeutics that offer an alternative method to modulate traditionally 'undrugable' targets. In the case of dominantly inherited neurodegenerative diseases, gene suppression strategies can target the underlying cause of these intractable disorders. Polyglutamine diseases are caused by CAG expansions in discrete genes, making them ideal candidates for gene suppression therapies. Here, we discuss the current state of gene suppression approaches for Huntington's disease and the spinocerebellar ataxias, including the use of antisense oligonucleotides, short-interfering RNAs, as well as viral vector-mediated delivery of short hairpin RNAs and artificial microRNAs. We focus on lessons learned from preclinical studies investigating gene suppression therapies for these disorders, particularly in rodent models of disease and in non-human primates. In animal models, recent advances in gene suppression technologies have not only prevented disease progression in a number of cases, but have also reversed existing disease, providing evidence that reducing the expression of disease-causing genes may be of benefit in symptomatic patients. Both allele- and non-allele-specific approaches to gene suppression have made great strides over the past decade, showing efficacy and safety in both small and large animal models. Advances in delivery techniques allow for broad and durable suppression of target genes, have been validated in non-human primates and in some cases, are currently being evaluated in human patients. Finally, we discuss the challenges of developing and delivering gene suppression constructs into the CNS and recent advances of potential therapeutics into the clinic.
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Affiliation(s)
- Megan S Keiser
- Raymond G. Perlman Center for Cellular and Molecular Therapeutics, The Children's Hospital of Philadelphia, Philadelphia, PA, USA
| | | | - Jodi L McBride
- Department of Neurology, Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, USA and Deparment of Neuroscience, Oregon National Primate Research Center, Beaverton, OR, USA
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Gramlich OW, Ding QJ, Zhu W, Cook A, Anderson MG, Kuehn MH. Adoptive transfer of immune cells from glaucomatous mice provokes retinal ganglion cell loss in recipients. Acta Neuropathol Commun 2015; 3:56. [PMID: 26374513 PMCID: PMC4591529 DOI: 10.1186/s40478-015-0234-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 08/21/2015] [Indexed: 12/02/2022] Open
Abstract
INTRODUCTION Several studies have indicated that autoimmune and neuroinflammatory processes contribute to the neurodegeneration of retinal ganglion cells in human glaucoma patients and in animal models. To test the involvement of cellular immune processes in the pathophysiology of retinal ganglion cell degeneration in vivo, we carried out adoptive transfer experiments from two independent genetic mouse models of glaucoma into normal recipient mice. RESULTS Our findings indicate that transfer results in a progressive loss of retinal ganglion cells and their axons despite normal intraocular pressure in recipient mice. Signs of pan-retinal inflammation were not detected. Similar findings were obtained following transfer of isolated T-lymphocytes, but not after transfer of splenocytes from immune deficient glaucomatous mice. Transferred lymphocytes were detected integrated in the spleen and in the retinal ganglion cell layer of recipient animals, albeit at very low frequencies. Furthermore, we observed cell-cell interaction between transferred T-cells and recipient microglia along with focal microglial activation in recipient eyes. CONCLUSION This study demonstrates that the pathophysiology of glaucomatous degeneration in the tested animal models includes T-cell mediated events that are capable of causing loss of healthy retinal ganglion cells.
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Affiliation(s)
- Oliver W Gramlich
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA
- Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, 3135C MERF, 375 Newton Road, Iowa City, IA, 52242, USA
| | - Qiong J Ding
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA
| | - Wei Zhu
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA
| | - Amy Cook
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA
| | - Michael G Anderson
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA
- Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, 3135C MERF, 375 Newton Road, Iowa City, IA, 52242, USA
- Department of Molecular Physiology and Biophysics, The University of Iowa, Iowa City, 52242, IA, USA
| | - Markus H Kuehn
- Department of Ophthalmology and Visual Sciences, The University of Iowa, Iowa City, 52242, IA, USA.
- Center for the Prevention and Treatment of Visual Loss, Iowa City VA Health Care System, 3135C MERF, 375 Newton Road, Iowa City, IA, 52242, USA.
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O'Connor DM, Boulis NM. Gene therapy for neurodegenerative diseases. Trends Mol Med 2015; 21:504-12. [PMID: 26122838 DOI: 10.1016/j.molmed.2015.06.001] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 12/18/2022]
Abstract
Gene therapy is, potentially, a powerful tool for treating neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), spinal muscular atrophy, Parkinson's disease (PD) and Alzheimer's disease (AD). To date, clinical trials have failed to show any improvement in outcome beyond the placebo effect. Efforts to improve outcomes are focusing on three main areas: vector design and the identification of new vector serotypes, mode of delivery of gene therapies, and identification of new therapeutic targets. These advances are being tested both individually and together to improve efficacy. These improvements may finally make gene therapy successful for these disorders.
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Affiliation(s)
- Deirdre M O'Connor
- Department of Neurosurgery, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA
| | - Nicholas M Boulis
- Department of Neurosurgery, Emory University, 101 Woodruff Circle, Atlanta, GA 30322, USA.
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