1
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Brunet de Courssou JB, Durr A, Adams D, Corvol JC, Mariani LL. Antisense therapies in neurological diseases. Brain 2021; 145:816-831. [PMID: 35286370 DOI: 10.1093/brain/awab423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 10/16/2021] [Accepted: 11/01/2021] [Indexed: 12/18/2022] Open
Abstract
Advances in targeted regulation of gene expression allowed new therapeutic approaches for monogenic neurological diseases. Molecular diagnosis has paved the way to personalized medicine targeting the pathogenic roots: DNA or its RNA transcript. These antisense therapies rely on modified nucleotides sequences (single-strand DNA or RNA, both belonging to the antisense oligonucleotides family, or double-strand interfering RNA) to act specifically on pathogenic target nucleic acids, thanks to complementary base pairing. Depending on the type of molecule, chemical modifications and target, base pairing will lead alternatively to splicing modifications of primary transcript RNA or transient messenger RNA degradation or non-translation. The key to success for neurodegenerative diseases also depends on the ability to reach target cells. The most advanced antisense therapies under development in neurological disorders are presented here, at the clinical stage of development, either at phase 3 or market authorization stage, such as in spinal amyotrophy, Duchenne muscular dystrophy, transthyretin-related hereditary amyloidosis, porphyria and amyotrophic lateral sclerosis; or in earlier clinical phase 1 B, for Huntington disease, synucleinopathies and tauopathies. We also discuss antisense therapies at the preclinical stage, such as in some tauopathies, spinocerebellar ataxias or other rare neurological disorders. Each subtype of antisense therapy, antisense oligonucleotides or interfering RNA, has proved target engagement or even clinical efficacy in patients; undisputable recent advances for severe and previously untreatable neurological disorders. Antisense therapies show great promise, but many unknowns remain. Expanding the initial successes achieved in orphan or rare diseases to other disorders will be the next challenge, as shown by the recent failure in Huntington disease or due to long-term preclinical toxicity in multiple system atrophy and cystic fibrosis. This will be critical in the perspective of new planned applications to premanifest mutation carriers, or other non-genetic degenerative disorders such as multiple system atrophy or Parkinson disease.
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Affiliation(s)
- Jean-Baptiste Brunet de Courssou
- Assistance Publique Hôpitaux de Paris, Department of Neurology, CIC Neurosciences, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France
| | - Alexandra Durr
- Sorbonne University, Paris Brain Institute - ICM, Inserm, CNRS, Paris, France
| | - David Adams
- Department of Neurology, Bicêtre hospital, Assistance Publique Hôpitaux de Paris, Centre de Référence National des Neuropathies Périphériques Rares, Paris Saclay University, INSERM U 1195, Le Kremlin Bicêtre, France
| | - Jean-Christophe Corvol
- Assistance Publique Hôpitaux de Paris, Department of Neurology, CIC Neurosciences, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France.,Sorbonne University, Paris Brain Institute - ICM, Inserm, CNRS, Paris, France
| | - Louise-Laure Mariani
- Assistance Publique Hôpitaux de Paris, Department of Neurology, CIC Neurosciences, Pitié-Salpêtrière Hospital, Sorbonne University, Paris, France.,Sorbonne University, Paris Brain Institute - ICM, Inserm, CNRS, Paris, France
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2
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Prudencio M, Garcia-Moreno H, Jansen-West KR, Al-Shaikh RH, Gendron TF, Heckman MG, Spiegel MR, Carlomagno Y, Daughrity LM, Song Y, Dunmore JA, Byron N, Oskarsson B, Nicholson KA, Staff NP, Gorcenco S, Puschmann A, Lemos J, Januário C, LeDoux MS, Friedman JH, Polke J, Labrum R, Shakkottai V, McLoughlin HS, Paulson HL, Konno T, Onodera O, Ikeuchi T, Tada M, Kakita A, Fryer JD, Karremo C, Gomes I, Caviness JN, Pittelkow MR, Aasly J, Pfeiffer RF, Veerappan V, Eggenberger ER, Freeman WD, Huang JF, Uitti RJ, Wierenga KJ, Marin Collazo IV, Tipton PW, van Gerpen JA, van Blitterswijk M, Bu G, Wszolek ZK, Giunti P, Petrucelli L. Toward allele-specific targeting therapy and pharmacodynamic marker for spinocerebellar ataxia type 3. Sci Transl Med 2021; 12:12/566/eabb7086. [PMID: 33087504 DOI: 10.1126/scitranslmed.abb7086] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 06/30/2020] [Indexed: 12/13/2022]
Abstract
Spinocerebellar ataxia type 3 (SCA3), caused by a CAG repeat expansion in the ataxin-3 gene (ATXN3), is characterized by neuronal polyglutamine (polyQ) ATXN3 protein aggregates. Although there is no cure for SCA3, gene-silencing approaches to reduce toxic polyQ ATXN3 showed promise in preclinical models. However, a major limitation in translating putative treatments for this rare disease to the clinic is the lack of pharmacodynamic markers for use in clinical trials. Here, we developed an immunoassay that readily detects polyQ ATXN3 proteins in human biological fluids and discriminates patients with SCA3 from healthy controls and individuals with other ataxias. We show that polyQ ATXN3 serves as a marker of target engagement in human fibroblasts, which may bode well for its use in clinical trials. Last, we identified a single-nucleotide polymorphism that strongly associates with the expanded allele, thus providing an exciting drug target to abrogate detrimental events initiated by mutant ATXN3. Gene-silencing strategies for several repeat diseases are well under way, and our results are expected to improve clinical trial preparedness for SCA3 therapies.
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Affiliation(s)
- Mercedes Prudencio
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - Hector Garcia-Moreno
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.,Ataxia Centre, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London WC1N 3BG, UK
| | | | | | - Tania F Gendron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - Michael G Heckman
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Matthew R Spiegel
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Yari Carlomagno
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | | | - Yuping Song
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Judith A Dunmore
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Natalie Byron
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Björn Oskarsson
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Katharine A Nicholson
- Sean M. Healey and AMG Center for ALS, Massachusetts General Hospital (MGH), Boston, MA 02114, USA
| | - Nathan P Staff
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Sorina Gorcenco
- Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Neurology, Lund 22185, Sweden
| | - Andreas Puschmann
- Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Neurology, Lund 22185, Sweden
| | - João Lemos
- Coimbra University Hospital Centre, Coimbra University, Coimbra 3000-075, Portugal
| | - Cristina Januário
- Coimbra University Hospital Centre, Coimbra University, Coimbra 3000-075, Portugal
| | - Mark S LeDoux
- University of Memphis and Veracity Neuroscience LLC, Memphis, TN 38152, USA
| | - Joseph H Friedman
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, RI 02906, USA
| | - James Polke
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.,Ataxia Centre, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London WC1N 3BG, UK
| | - Robin Labrum
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK.,Ataxia Centre, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London WC1N 3BG, UK
| | - Vikram Shakkottai
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | | | - Henry L Paulson
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Takuya Konno
- Department of Neurology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Osamu Onodera
- Department of Neurology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Takeshi Ikeuchi
- Department of Molecular Genetics, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Mari Tada
- Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Akiyoshi Kakita
- Department of Pathology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - John D Fryer
- Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA.,Department of Neuroscience, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Christin Karremo
- Lund University, Skåne University Hospital, Department of Clinical Sciences Lund, Neurology, Lund 22185, Sweden
| | - Inês Gomes
- Coimbra University Hospital Centre, Coimbra University, Coimbra 3000-075, Portugal
| | - John N Caviness
- Department of Neurology, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Mark R Pittelkow
- Department of Dermatology, Mayo Clinic, Scottsdale, AZ 85259, USA
| | - Jan Aasly
- Norwegian University of Science and Technology, 7006 Trondheim, Norway
| | - Ronald F Pfeiffer
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Venka Veerappan
- Department of Neurology, Oregon Health & Science University, Portland, OR 97239, USA
| | | | | | | | - Ryan J Uitti
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | - Klaas J Wierenga
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Philip W Tipton
- Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA
| | | | - Marka van Blitterswijk
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | - Guojun Bu
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA.,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
| | | | - Paola Giunti
- Ataxia Centre, Department of Clinical and Movement Neurosciences, UCL Queen Square Institute of Neurology, London WC1N 3BG, UK. .,Ataxia Centre, National Hospital for Neurology and Neurosurgery, University College London Hospitals NHS Trust, London WC1N 3BG, UK
| | - Leonard Petrucelli
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL 32224, USA. .,Neuroscience Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Jacksonville, FL 32224, USA
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3
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Artificial miRNAs targeting CAG repeat expansion in ORFs cause rapid deadenylation and translation inhibition of mutant transcripts. Cell Mol Life Sci 2020; 78:1577-1596. [PMID: 32696070 PMCID: PMC7904544 DOI: 10.1007/s00018-020-03596-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 07/01/2020] [Accepted: 07/09/2020] [Indexed: 02/07/2023]
Abstract
Polyglutamine (polyQ) diseases are incurable neurological disorders caused by CAG repeat expansion in the open reading frames (ORFs) of specific genes. This type of mutation in the HTT gene is responsible for Huntington’s disease (HD). CAG repeat-targeting artificial miRNAs (art-miRNAs) were shown as attractive therapeutic approach for polyQ disorders as they caused allele-selective decrease in the level of mutant proteins. Here, using polyQ disease models, we aimed to demonstrate how miRNA-based gene expression regulation is dependent on target sequence features. We show that the silencing efficiency and selectivity of art-miRNAs is influenced by the localization of the CAG repeat tract within transcript and the specific sequence context. Furthermore, we aimed to reveal the events leading to downregulation of mutant polyQ proteins and found very rapid activation of translational repression and HTT transcript deadenylation. Slicer-activity of AGO2 was dispensable in this process, as determined in AGO2 knockout cells generated with CRISPR-Cas9 technology. We also showed highly allele-selective downregulation of huntingtin in human HD neural progenitors (NPs). Taken together, art-miRNA activity may serve as a model of the cooperative activity and targeting of ORF regions by endogenous miRNAs.
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4
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Mesenchymal stem cell-derived exosomes improve motor function and attenuate neuropathology in a mouse model of Machado-Joseph disease. Stem Cell Res Ther 2020; 11:222. [PMID: 32513306 PMCID: PMC7278177 DOI: 10.1186/s13287-020-01727-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 04/19/2020] [Accepted: 05/12/2020] [Indexed: 12/12/2022] Open
Abstract
Background Machado-Joseph disease is the most common autosomal dominant hereditary ataxia worldwide without effective treatment. Mesenchymal stem cells (MSCs) could slow the disease progression, but side effects limited their clinical application. Besides, MSC-derived exosomes exerted similar efficacy and have many advantages over MSCs. The aim of this study was to examine the efficacy of MSC-derived exosomes in YACMJD84.2 mice. Methods Rotarod performance was evaluated every 2 weeks after a presymptomatic administration of intravenous MSC-derived exosomes twice in YACMJD84.2 mice. Loss of Purkinje cells, relative expression level of Bcl-2/Bax, cerebellar myelin loss, and neuroinflammation were assessed 8 weeks following treatment. Results MSC-derived exosomes were isolated and purified through anion exchange chromatography. Better coordination in rotarod performance was maintained for 6 weeks in YACMJD84.2 mice with exosomal treatment, compared with those without exosomal treatment. Neuropathological changes including loss of Purkinje cells, cerebellar myelin loss, and neuroinflammation were also attenuated 8 weeks after exosomal treatment. The higher relative ratio of Bcl-2/Bax was consistent with the attenuation of loss of Purkinje cells. Conclusions MSC-derived exosomes could promote rotarod performance and attenuate neuropathology, including loss of Purkinje cells, cerebellar myelin loss, and neuroinflammation. Therefore, MSC-derived exosomes have a great potential in the treatment of Machado-Joseph disease.
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5
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Gonzalez-Alegre P. Recent advances in molecular therapies for neurological disease: triplet repeat disorders. Hum Mol Genet 2020; 28:R80-R87. [PMID: 31227833 DOI: 10.1093/hmg/ddz138] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 04/03/2019] [Accepted: 06/11/2019] [Indexed: 02/06/2023] Open
Abstract
Triplet repeat diseases (TRDs) are caused by pathogenic expansions of trinucleotide sequence repeats within coding and non-coding regions of different genes. They are typically progressive, very disabling and frequently involve the nervous system. Currently available symptomatic therapies provide modest benefit at best. The development of interventions that interfere with the natural history of these diseases is a priority. A common pathogenic process shared by most TRDs is the presence of toxicity from the messenger RNA or protein encoded by the gene harboring the abnormal expansion. Strategies to interfere with the expression of these genes using different molecular approaches are being pursued and have reached the clinical stage. This review will summarize the significant progress made in this field in the last few years, focusing on three main areas: the discovery of biomarkers of disease progression and target engagement, advances in preclinical studies for the polyglutamine ataxias and the initial clinical application in myotonic dystrophy type 1 and Huntington's disease.
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Affiliation(s)
- Pedro Gonzalez-Alegre
- Department of Neurology, the University of Pennsylvania, Philadelphia, PA 19104, USA.,Raymond G. Perelman Center for Cellular and Molecular Therapy, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
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6
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Kotowska-Zimmer A, Ostrovska Y, Olejniczak M. Universal RNAi Triggers for the Specific Inhibition of Mutant Huntingtin, Atrophin-1, Ataxin-3, and Ataxin-7 Expression. MOLECULAR THERAPY. NUCLEIC ACIDS 2019; 19:562-571. [PMID: 31927329 PMCID: PMC6957814 DOI: 10.1016/j.omtn.2019.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 12/04/2019] [Accepted: 12/11/2019] [Indexed: 12/13/2022]
Abstract
The expansion of CAG repeats within the coding region of associated genes is responsible for nine inherited neurodegenerative disorders including Huntington’s disease (HD), spinocerebellar ataxias (SCAs), and dentatorubral-pallidoluysian atrophy (DRPLA). Despite years of research aimed at developing an effective method of treatment, these diseases remain incurable and only their symptoms are controlled. The purpose of this study was to develop effective and allele-selective genetic tools for silencing the expression of mutated genes containing expanded CAG repeats. Here we show that repeat-targeting short hairpin RNAs preferentially reduce the levels of mutant huntingtin, atrophin-1, ataxin-3, and ataxin-7 proteins in patient-derived fibroblasts and may serve as universal allele-selective reagents for polyglutamine (polyQ) diseases.
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Affiliation(s)
- Anna Kotowska-Zimmer
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Yuliya Ostrovska
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Marta Olejniczak
- Department of Genome Engineering, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland; Dystrogen Gene Therapies, 1415 W 37(th) Street, Chicago, IL, USA.
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7
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Martier R, Sogorb-Gonzalez M, Stricker-Shaver J, Hübener-Schmid J, Keskin S, Klima J, Toonen LJ, Juhas S, Juhasova J, Ellederova Z, Motlik J, Haas E, van Deventer S, Konstantinova P, Nguyen HP, Evers MM. Development of an AAV-Based MicroRNA Gene Therapy to Treat Machado-Joseph Disease. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 15:343-358. [PMID: 31828177 PMCID: PMC6889651 DOI: 10.1016/j.omtm.2019.10.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 10/22/2019] [Indexed: 01/06/2023]
Abstract
Spinocerebellar ataxia type 3 (SCA3), or Machado-Joseph disease (MJD), is a progressive neurodegenerative disorder caused by a CAG expansion in the ATXN3 gene. The expanded CAG repeat is translated into a prolonged polyglutamine repeat in the ataxin-3 protein and accumulates within inclusions, acquiring toxic properties, which results in degeneration of the cerebellum and brain stem. In the current study, a non-allele-specific ATXN3 silencing approach was investigated using artificial microRNAs engineered to target various regions of the ATXN3 gene (miATXN3). The miATXN3 candidates were screened in vitro based on their silencing efficacy on a luciferase (Luc) reporter co-expressing ATXN3. The three best miATXN3 candidates were further tested for target engagement and potential off-target activity in induced pluripotent stem cells (iPSCs) differentiated into frontal brain-like neurons and in a SCA3 knockin mouse model. Besides a strong reduction of ATXN3 mRNA and protein, small RNA sequencing revealed efficient guide strand processing without passenger strands being produced. We used different methods to predict alteration of off-target genes upon AAV5-miATXN3 treatment and found no evidence for unwanted effects. Furthermore, we demonstrated in a large animal model, the minipig, that intrathecal delivery of AAV5 can transduce the main areas affected in SCA3 patients. These results proved a strong basis to move forward to investigate distribution, efficacy, and safety of AAV5-miATXN3 in large animals.
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Affiliation(s)
- Raygene Martier
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Marina Sogorb-Gonzalez
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Janice Stricker-Shaver
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | | | - Sonay Keskin
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Jiri Klima
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Lodewijk J Toonen
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Stefan Juhas
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Jana Juhasova
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Zdenka Ellederova
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Jan Motlik
- Institute of Animal Physiology and Genetics, Libechov, Czech Republic
| | - Eva Haas
- Institute of Medical Genetics and Applied Genomics, University of Tuebingen, Tuebingen, Germany
| | - Sander van Deventer
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands.,Department of Gastroenterology and Hepatology, Leiden University Medical Center, Leiden, the Netherlands
| | - Pavlina Konstantinova
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
| | - Huu Phuc Nguyen
- Department of Human Genetics, Medical Faculty, Ruhr University Bochum, Bochum, Germany
| | - Melvin M Evers
- Department of Research & Development, uniQure Biopharma B.V., Amsterdam, the Netherlands
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8
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Goh E, Okamura K. Hidden sequence specificity in loading of single-stranded RNAs onto Drosophila Argonautes. Nucleic Acids Res 2019; 47:3101-3116. [PMID: 30590701 PMCID: PMC6451100 DOI: 10.1093/nar/gky1300] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 12/16/2018] [Accepted: 12/18/2018] [Indexed: 12/21/2022] Open
Abstract
Argonaute proteins play important roles in gene regulation with small RNAs (sRNAs) serving as guides to targets. Argonautes are believed to bind sRNAs in a sequence non-specific manner. However, we recently discovered that Argonautes selectively load endogenous single-stranded (ss) RNAs, suggesting that Argonaute loading may conform to sequence specificity. To identify sequences preferred for Argonaute loading, we have developed HIgh-throughput Sequencing mediated Specificity Analysis (HISSA). HISSA allows massively parallel analysis of RNA binding efficiency by using randomized oligos in in vitro binding assays and quantifying RNAs by deep-sequencing. We chose Drosophila as a model system to take advantage of the presence of two biochemically distinct Argonautes, AGO1 and AGO2. Our results revealed AGO2 loading to be strongly favored by G-rich sequences. In contrast, AGO1 showed an enrichment of the ‘GAC’ motif in loaded species. Reanalysis of published sRNA sequencing data from fly tissues detected enrichment of the GAC motif in ssRNA-derived small RNAs in the immunopurified AGO1-complex under certain conditions, suggesting that the sequence preference of AGO1-loading may influence the repertoire of AGO1-bound endogenous sRNAs. Finally, we showed that human Ago2 also exhibited selectivity in loading ssRNAs in cell lysates. These findings may have implications for therapeutic ssRNA-mediated gene silencing.
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Affiliation(s)
- Eling Goh
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore 117604, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798, Singapore
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore 117604, Singapore.,School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 639798, Singapore
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9
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Kourkouta E, Weij R, González-Barriga A, Mulder M, Verheul R, Bosgra S, Groenendaal B, Puoliväli J, Toivanen J, van Deutekom JCT, Datson NA. Suppression of Mutant Protein Expression in SCA3 and SCA1 Mice Using a CAG Repeat-Targeting Antisense Oligonucleotide. MOLECULAR THERAPY-NUCLEIC ACIDS 2019; 17:601-614. [PMID: 31394429 PMCID: PMC6695277 DOI: 10.1016/j.omtn.2019.07.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 06/26/2019] [Accepted: 07/08/2019] [Indexed: 10/26/2022]
Abstract
Spinocerebellar ataxia type 3 (SCA3) and type 1 (SCA1) are dominantly inherited neurodegenerative disorders that are currently incurable. Both diseases are caused by a CAG-repeat expansion in exon 10 of the Ataxin-3 and exon 8 of the Ataxin-1 gene, respectively, encoding an elongated polyglutamine tract that confers toxic properties to the resulting proteins. We have previously shown lowering of the pathogenic polyglutamine protein in Huntington's disease mouse models using (CUG)7, a CAG repeat-targeting antisense oligonucleotide. Here we evaluated the therapeutic capacity of (CUG)7 for SCA3 and SCA1, in vitro in patient-derived cell lines and in vivo in representative mouse models. Repeated intracerebroventricular (CUG)7 administration resulted in a significant reduction of mutant Ataxin-3 and Ataxin-1 proteins throughout the brain of SCA3 and SCA1 mouse models, respectively. Furthermore, in both a SCA3 patient cell line and the MJD84.2 mouse model, (CUG)7 induced formation of a truncated Ataxin-3 protein species lacking the polyglutamine stretch, likely arising from (CUG)7-mediated exon 10 skipping. In contrast, skipping of exon 8 of Ataxin-1 did not significantly contribute to the Ataxin-1 protein reduction observed in (CUG)7-treated SCA1154Q/2Q mice. These findings support the therapeutic potential of a single CAG repeat-targeting AON for the treatment of multiple polyglutamine disorders.
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Affiliation(s)
| | - Rudie Weij
- BioMarin Nederland BV, Leiden, the Netherlands
| | | | | | | | | | | | | | - Jussi Toivanen
- Charles River Discovery Research Services, Kuopio, Finland
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10
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Weng Y, Xiao H, Zhang J, Liang XJ, Huang Y. RNAi therapeutic and its innovative biotechnological evolution. Biotechnol Adv 2019; 37:801-825. [PMID: 31034960 DOI: 10.1016/j.biotechadv.2019.04.012] [Citation(s) in RCA: 173] [Impact Index Per Article: 34.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 04/09/2019] [Accepted: 04/23/2019] [Indexed: 02/06/2023]
Abstract
Recently, United States Food and Drug Administration (FDA) and European Commission (EC) approved Alnylam Pharmaceuticals' RNA interference (RNAi) therapeutic, ONPATTRO™ (Patisiran), for the treatment of the polyneuropathy of hereditary transthyretin-mediated (hATTR) amyloidosis in adults. This is the first RNAi therapeutic all over the world, as well as the first FDA-approved treatment for this indication. As a milestone event in RNAi pharmaceutical industry, it means, for the first time, people have broken through all development processes for RNAi drugs from research to clinic. With this achievement, RNAi approval may soar in the coming years. In this paper, we introduce the basic information of ONPATTRO and the properties of RNAi and nucleic acid therapeutics, update the clinical and preclinical development activities, review its complicated development history, summarize the key technologies of RNAi at early stage, and discuss the latest advances in delivery and modification technologies. It provides a comprehensive view and biotechnological insights of RNAi therapy for the broader audiences.
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Affiliation(s)
- Yuhua Weng
- Advanced Research Institute of Multidisciplinary Science, School of Life Science, Key Laboratory of Molecular Medicine and Biotherapy, Beijing Institute of Technology, Beijing 100081, PR China
| | - Haihua Xiao
- Beijing National Laboratory for Molecular Sciences, State Key Laboratory of Polymer Physics and Chemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190, PR China
| | - Jinchao Zhang
- College of Chemistry & Environmental Science, Chemical Biology Key Laboratory of Hebei Province, Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of the Ministry of Education, Hebei University, Baoding 071002, PR China
| | - Xing-Jie Liang
- Chinese Academy of Sciences (CAS) Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology of China, Beijing 100190, PR China
| | - Yuanyu Huang
- Advanced Research Institute of Multidisciplinary Science, School of Life Science, Key Laboratory of Molecular Medicine and Biotherapy, Beijing Institute of Technology, Beijing 100081, PR China.
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11
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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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12
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Hu J, Shen X, Rigo F, Prakash TP, Mootha VV, Corey DR. Duplex RNAs and ss-siRNAs Block RNA Foci Associated with Fuchs' Endothelial Corneal Dystrophy. Nucleic Acid Ther 2019; 29:73-81. [PMID: 30676271 DOI: 10.1089/nat.2018.0764] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fuchs' endothelial corneal dystrophy (FECD) leads to vision loss and is one of the most common inherited eye diseases. Corneal transplants are the only curative treatment available, and there is a major unmet need for treatments that are less invasive and independent of donor tissue. Most cases of FECD are associated with an expanded CUG repeat within the intronic region of TCF4 and the mutant RNA has been implicated as the cause of the disease. We previously presented preliminary data suggesting that single-stranded antisense oligonucleotides (ASOs) can inhibit CUG RNA foci in patient-derived cells and tissue. We now show that duplex RNAs and single-stranded silencing RNAs (ss-siRNAs) reduce the number of cells with foci and the number of foci per cells. Potencies are similar to those that are achieved with chemically modified ASOs designed to block foci. These data widen the potential for synthetic nucleic acids to be used to treat a widely prevalent and debilitating disease.
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Affiliation(s)
- Jiaxin Hu
- 1 Department of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas
| | - Xiulong Shen
- 1 Department of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas
| | - Frank Rigo
- 2 Ionis Pharmaceuticals, Carlsbad, California
| | | | - V Vinod Mootha
- 3 Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas.,4 McDermott Center for Human Growth and Development, UT Southwestern Medical Center, Dallas, Texas
| | - David R Corey
- 1 Department of Pharmacology and Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, Texas
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13
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Matos CA, de Almeida LP, Nóbrega C. Machado-Joseph disease/spinocerebellar ataxia type 3: lessons from disease pathogenesis and clues into therapy. J Neurochem 2018; 148:8-28. [PMID: 29959858 DOI: 10.1111/jnc.14541] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 06/05/2018] [Accepted: 06/27/2018] [Indexed: 12/25/2022]
Abstract
Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an incurable disorder, widely regarded as the most common form of spinocerebellar ataxia in the world. MJD/SCA3 arises from mutation of the ATXN3 gene, but this simple monogenic cause contrasts with the complexity of the pathogenic mechanisms that are currently admitted to underlie neuronal dysfunction and death. The aberrantly expanded protein product - ataxin-3 - is known to aggregate and generate toxic species that disrupt several cell systems, including autophagy, proteostasis, transcription, mitochondrial function and signalling. Over the years, research into putative therapeutic approaches has often been devoted to the development of strategies that counteract disease at different stages of cellular pathogenesis. Silencing the pathogenic protein, blocking aggregation, inhibiting toxic proteolytic processing and counteracting dysfunctions of the cellular systems affected have yielded promising ameliorating results in studies with cellular and animal models. The current review analyses the available studies dedicated to the investigation of MJD/SCA3 pathogenesis and the exploration of possible therapeutic strategies, focusing primarily on gene therapy and pharmacological approaches rooted on the molecular and cellular mechanisms of disease.
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Affiliation(s)
- Carlos A Matos
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Institute for Interdisciplinary Research, University of Coimbra, Coimbra, Portugal
| | - Luís Pereira de Almeida
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal
| | - Clévio Nóbrega
- Center for Neuroscience and Cell Biology (CNC), University of Coimbra, Coimbra, Portugal.,Department of Biomedical Sciences and Medicine, University of Algarve, Coimbra, Portugal.,Centre for Biomedical Research (CBMR), University of Algarve, Coimbra, Portugal.,Algarve Biomedical Center (ABC), University of Algarve, Faro, Portugal
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14
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Shen X, Kilikevicius A, O'Reilly D, Prakash TP, Damha MJ, Rigo F, Corey DR. Activating frataxin expression by single-stranded siRNAs targeting the GAA repeat expansion. Bioorg Med Chem Lett 2018; 28:2850-2855. [PMID: 30076049 PMCID: PMC6129981 DOI: 10.1016/j.bmcl.2018.07.033] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 07/17/2018] [Accepted: 07/18/2018] [Indexed: 11/18/2022]
Abstract
Friedreich's ataxia (FRDA) is an incurable neurodegenerative disorder caused by reduced expression of the mitochondrial protein frataxin (FXN). The genetic cause of the disease is an expanded GAA repeat within the FXN gene. Agents that increase expression of FXN protein are a potential approach to therapy. We previously described anti-trinucleotide GAA duplex RNAs (dsRNAs) and antisense oligonucleotides (ASOs) that activate FXN protein expression in multiple patient derived cell lines. Here we test two distinct series of compounds for their ability to increase FXN expression. ASOs with butane linkers showed low potency, which is consistent with the low Tm values and suggesting that flexible conformation impairs activity. By contrast, single-stranded siRNAs (ss-siRNAs) that combine the strengths of dsRNA and ASO approaches had nanomolar potencies. ss-siRNAs provide an additional option for developing nucleic acid therapeutics to treat FRDA.
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Affiliation(s)
- Xiulong Shen
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States
| | - Audrius Kilikevicius
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States
| | - Daniel O'Reilly
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | | | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, QC H3A 0B8, Canada
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92010, United States
| | - David R Corey
- Department of Pharmacology, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States; Department of Biochemistry, UT Southwestern Medical Center at Dallas, Dallas, TX 75390, United States.
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15
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Ouyang S, Xie Y, Xiong Z, Yang Y, Xian Y, Ou Z, Song B, Chen Y, Xie Y, Li H, Sun X. CRISPR/Cas9-Targeted Deletion of Polyglutamine in Spinocerebellar Ataxia Type 3-Derived Induced Pluripotent Stem Cells. Stem Cells Dev 2018; 27:756-770. [PMID: 29661116 DOI: 10.1089/scd.2017.0209] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Spinocerebellar ataxia type 3 (SCA3) is caused by an abnormal expansion of the cytosine-adenine-guanine (CAG) triplet in ATXN3, which translates into a polyglutamine (polyQ) tract within ataxin-3 (ATXN3) protein. Although the pathogenic mechanisms remain unclear, it is well established that expression of mutant forms of ATXN3 carrying an expanded polyQ domain are involved in SCA3 pathogenesis, and several strategies to suppress mutant ATXN3 have shown promising potential for SCA3 treatment. In this study, we described successful clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9-mediated deletion of the expanded polyQ-encoding region of ATXN3 in induced pluripotent stem cells (iPSCs) derived from a SCA3 patient, and these patient-specific iPSCs retained pluripotency and neural differentiation following expanded polyQ deletion. Furthermore, the ubiquitin-binding capacity of ATXN3 was retained in the neural cells differentiated from the corrected iPSCs. For the first time, this work provides preliminary data for gene editing by CRISPR/Cas9 in SCA3, and demonstrates the feasibility of using a single-guide RNA pair to delete the expanded polyQ-encoding region of ATXN3, suggesting the potential efficacy of this method for future therapeutic application.
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Affiliation(s)
- Shuming Ouyang
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Yingjun Xie
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Zeyu Xiong
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Yi Yang
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Yexing Xian
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Zhanhui Ou
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Bing Song
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Yuchang Chen
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Yuhuan Xie
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Haoxian Li
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
| | - Xiaofang Sun
- Key Laboratory for Major Obstetric Diseases of Guangdong Province, Key Laboratory of Reproduction and Genetics of Guangdong Higher Education Institutes, The Third Affiliated Hospital of Guangzhou Medical University , Guangzhou City, People's Republic of China
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16
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Goh E, Okamura K. Gateway to Understanding Argonaute Loading of Single-Stranded RNAs: Preparation of Deep Sequencing Libraries with In Vitro Loading Samples. Methods Mol Biol 2018; 1680:41-63. [PMID: 29030840 DOI: 10.1007/978-1-4939-7339-2_3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Identification of sequences preferred by individual RNA-binding proteins (RBPs) has been accelerated by recent advances in the quantitative analysis of protein-RNA interactions on a massive scale, and such experiments have even revealed hidden sequence specificity of RBPs that were assumed to be non-specific. Argonaute (AGO) proteins bind diverse guide small RNAs and were believed to have no sequence specificity besides the preference for particular bases at the 5' nucleotide. However, we recently showed that short single-stranded RNAs (ssRNAs) are loaded to AGOs in vivo and in cell extracts with detectable sequence preferences. To study the sequence specificity, we established a protocol for preparing the oligo-specific deep-sequencing library. The protocol includes in vitro loading assay that uses RNA oligos containing randomized nucleotides at the first five positions and also splinted-ligation that specifically amplifies the introduced oligo RNA species from a complex mixture of endogenous small RNAs and exogenously introduced RNA oligos. With the current sequencing depth, this procedure will allow quantitative profiling of interactions between the AGO and ~1000 ssRNA species with different sequences. The method would aid in studying the mechanism behind the selective loading of ssRNAs to AGOs and may potentially be applied to study interactions between RNA and other RNA-binding proteins.
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Affiliation(s)
- Eling Goh
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 639798, Singapore
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Singapore.
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore, 639798, Singapore.
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17
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Toonen LJA, Rigo F, van Attikum H, van Roon-Mom WMC. Antisense Oligonucleotide-Mediated Removal of the Polyglutamine Repeat in Spinocerebellar Ataxia Type 3 Mice. MOLECULAR THERAPY-NUCLEIC ACIDS 2017; 8:232-242. [PMID: 28918024 PMCID: PMC5504086 DOI: 10.1016/j.omtn.2017.06.019] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 06/21/2017] [Accepted: 06/24/2017] [Indexed: 11/05/2022]
Abstract
Spinocerebellar ataxia type 3 (SCA3) is a currently incurable neurodegenerative disorder caused by a CAG triplet expansion in exon 10 of the ATXN3 gene. The resultant expanded polyglutamine stretch in the mutant ataxin-3 protein causes a gain of toxic function, which eventually leads to neurodegeneration. One important function of ataxin-3 is its involvement in the proteasomal protein degradation pathway, and long-term downregulation of the protein may therefore not be desirable. In the current study, we made use of antisense oligonucleotides to mask predicted exonic splicing signals, resulting in exon 10 skipping from ATXN3 pre-mRNA. This led to formation of a truncated ataxin-3 protein lacking the toxic polyglutamine expansion, but retaining its ubiquitin binding and cleavage function. Repeated intracerebroventricular injections of the antisense oligonucleotides in a SCA3 mouse model led to exon skipping and formation of the modified ataxin-3 protein throughout the mouse brain. Exon skipping was long lasting, with the modified protein being detectable for at least 2.5 months after antisense oligonucleotide injection. A reduction in insoluble ataxin-3 and nuclear accumulation was observed following antisense oligonucleotide treatment, indicating a beneficial effect on pathogenicity. Together, these data suggest that exon 10 skipping is a promising therapeutic approach for SCA3.
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Affiliation(s)
- Lodewijk J A Toonen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, the Netherlands
| | - Frank Rigo
- Ionis Pharmaceuticals, Carlsbad, CA 92008, USA
| | - Haico van Attikum
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, the Netherlands
| | - Willeke M C van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, the Netherlands.
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18
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Hu J, Rigo F, Prakash TP, Corey DR. Recognition of c9orf72 Mutant RNA by Single-Stranded Silencing RNAs. Nucleic Acid Ther 2017; 27:87-94. [PMID: 28005462 PMCID: PMC5372765 DOI: 10.1089/nat.2016.0655] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 11/15/2016] [Indexed: 01/09/2023] Open
Abstract
Mutations within the chromosome 9 open reading frame 72 (c9orf72) gene are associated with both familial amyotrophic lateral sclerosis and frontotemporal dementia. The mutation leads to an expanded GGGGCC hexanucleotide repeat within the first intron of c9orf72 and an expanded CCCCGG repeat within a corresponding antisense transcript. Both the mutant intronic and antisense RNAs have been implicated in disease. We have previously reported that duplex RNAs complementary to the repeats can recognize disease-causing RNA and block detection of nuclear foci formed by the mutant transcripts. Here, we test the hypothesis that inhibition can also be achieved by single-stranded silencing RNAs (ss-siRNAs). ss-siRNAs are single-stranded antisense oligonucleotides (ASOs) that function through RNAi interference (RNAi) to silence gene expression. ss-siRNAs can block the expanded repeats within both intronic RNA and the antisense transcripts. Inhibition is more potent than by analogous duplex RNAs. Our data suggest that the potent effects on foci are caused by a combination of mechanisms including RNAi and direct binding of the ss-siRNA to the target transcripts. These findings reinforce the suggestion that ss-siRNAs combine the favorable properties of duplex RNA and single-stranded ASOs.
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Affiliation(s)
- Jiaxin Hu
- 1 Department of Pharmacology, UT Southwestern Medical Center at Dallas , Dallas, Texas
- 2 Department of Biochemistry, UT Southwestern Medical Center at Dallas , Dallas, Texas
| | - Frank Rigo
- 3 Ionis Pharmaceuticals , Carlsbad, California
| | | | - David R Corey
- 1 Department of Pharmacology, UT Southwestern Medical Center at Dallas , Dallas, Texas
- 2 Department of Biochemistry, UT Southwestern Medical Center at Dallas , Dallas, Texas
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19
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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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20
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Matsui M, Threlfall RN, Caruthers MH, Corey DR. Effect of 2'-O-methyl/thiophosphonoacetate-modified antisense oligonucleotides on huntingtin expression in patient-derived cells. ARTIFICIAL DNA, PNA & XNA 2016; 5:e1146391. [PMID: 26865404 DOI: 10.1080/1949095x.2016.1146391] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Optimizing oligonucleotides as therapeutics will require exploring how chemistry can be used to enhance their effects inside cells. To achieve this goal it will be necessary to fully explore chemical space around the native DNA/RNA framework to define the potential of diverse chemical modifications. In this report we examine the potential of thiophosphonoacetate (thioPACE)-modified 2'-O-methyl oligoribonucleotides as inhibitors of human huntingtin (HTT) expression. Inhibition occurred, but was less than with analogous locked nucleic acid (LNA)-substituted oligomers lacking the thioPACE modification. These data suggest that thioPACE oligonucleotides have the potential to control gene expression inside cells. However, advantages relative to other modifications were not demonstrated. Additional modifications are likely to be necessary to fully explore any potential advantages of thioPACE substitutions.
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Affiliation(s)
- Masayuki Matsui
- a Department of Pharmacology; UT Southwestern Medical Center ; Dallas , TX USA
| | - Richard N Threlfall
- b Department of Chemistry and Biochemistry ; University of Colorado at Boulder ; Boulder , CO USA
| | - Marvin H Caruthers
- b Department of Chemistry and Biochemistry ; University of Colorado at Boulder ; Boulder , CO USA
| | - David R Corey
- a Department of Pharmacology; UT Southwestern Medical Center ; Dallas , TX USA
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21
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Argonaute 2-dependent Regulation of Gene Expression by Single-stranded miRNA Mimics. Mol Ther 2016; 24:946-55. [PMID: 26903376 PMCID: PMC4881773 DOI: 10.1038/mt.2016.39] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Accepted: 02/08/2016] [Indexed: 01/11/2023] Open
Abstract
MicroRNAs (miRNAs) are small noncoding transcripts that regulate gene expression. Aberrant expression of miRNAs can affect development of cancer and other diseases. Synthetic miRNA mimics can modulate gene expression and offer an approach to therapy. Inside cells, mature miRNAs are produced as double-stranded RNAs and miRNA mimics typically retain both strands. This need for two strands has the potential to complicate drug development. Recently, synthetic chemically modified single-stranded silencing RNAs (ss-siRNA) have been shown to function through the RNAi pathway to induce gene silencing in cell culture and animals. Here, we test the hypothesis that single-stranded miRNA (ss-miRNA) can also mimic the function of miRNAs. We show that ss-miRNAs can act as miRNA mimics to silence the expression of target genes. Gene silencing requires expression of argonaute 2 (AGO2) protein and involves recruitment of AGO2 to the target transcripts. Chemically modified ss-miRNAs function effectively inside cells through endogenous RNAi pathways and broaden the options for miRNA-based oligonucleotide drug development.
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22
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Liu J, Hu J, Hicks JA, Prakash TP, Corey DR. Modulation of Splicing by Single-Stranded Silencing RNAs. Nucleic Acid Ther 2015; 25:113-20. [PMID: 25757055 DOI: 10.1089/nat.2014.0527] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Single-stranded silencing RNAs (ss-siRNAs) are chemically modified single-stranded oligonucleotides that can function through the cellular RNA interference (RNAi) machinery to modulate gene expression. Because their invention is recent, few studies have appeared describing their use and the potential of ss-siRNAs as a platform for controlling gene expression remains largely unknown. Using oligonucleotides to modulate splicing is an important area for therapeutic development and we tested the hypothesis that ss-siRNAs targeting splice sites might also be capable of directing increased production of therapeutically promising protein isoforms. Here we observe that ss-siRNAs alter splicing of dystrophin. Altered splicing requires a seed sequence complementarity to the target and expression of the RNAi factor argonaute 2. These results demonstrate that ss-siRNAs can be used to modulate splicing, providing another option for therapeutic development programs that aim to increase production of key protein isoforms. Splicing is a classical nuclear process and our data showing that it can be modulated through the action of RNA and RNAi factors offers further evidence that RNAi can take place in mammalian cell nuclei.
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Affiliation(s)
- Jing Liu
- 1Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas.,2Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Jiaxin Hu
- 1Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas.,2Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Jessica A Hicks
- 1Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas.,2Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | | | - David R Corey
- 1Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas.,2Department of Biochemistry, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
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23
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Eckstein F. Phosphorothioates, Essential Components of Therapeutic Oligonucleotides. Nucleic Acid Ther 2014; 24:374-87. [DOI: 10.1089/nat.2014.0506] [Citation(s) in RCA: 335] [Impact Index Per Article: 33.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Affiliation(s)
- Fritz Eckstein
- Max-Planck-Institut für Experimentelle Medizin, Göttingen, Germany
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24
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Trembley JH, Unger GM, Korman VL, Abedin MJ, Nacusi LP, Vogel RI, Slaton JW, Kren BT, Ahmed K. Tenfibgen ligand nanoencapsulation delivers bi-functional anti-CK2 RNAi oligomer to key sites for prostate cancer targeting using human xenograft tumors in mice. PLoS One 2014; 9:e109970. [PMID: 25333839 PMCID: PMC4198192 DOI: 10.1371/journal.pone.0109970] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2014] [Accepted: 09/02/2014] [Indexed: 01/11/2023] Open
Abstract
Protected and specific delivery of nucleic acids to malignant cells remains a highly desirable approach for cancer therapy. Here we present data on the physical and chemical characteristics, mechanism of action, and pilot therapeutic efficacy of a tenfibgen (TBG)-shell nanocapsule technology for tumor-directed delivery of single stranded DNA/RNA chimeric oligomers targeting CK2αα' to xenograft tumors in mice. The sub-50 nm size TBG nanocapsule (s50-TBG) is a slightly negatively charged, uniform particle of 15 - 20 nm size which confers protection to the nucleic acid cargo. The DNA/RNA chimeric oligomer (RNAi-CK2) functions to decrease CK2αα' expression levels via both siRNA and antisense mechanisms. Systemic delivery of s50-TBG-RNAi-CK2 specifically targets malignant cells, including tumor cells in bone, and at low doses reduces size and CK2-related signals in orthotopic primary and metastatic xenograft prostate cancer tumors. In conclusion, the s50-TBG nanoencapsulation technology together with the chimeric oligomer targeting CK2αα' offer significant promise for systemic treatment of prostate malignancy.
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Affiliation(s)
- Janeen H. Trembley
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
| | | | - Vicci L. Korman
- GeneSegues Inc., Chaska, Minnesota, United States of America
| | - Md. Joynal Abedin
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Lucas P. Nacusi
- GeneSegues Inc., Chaska, Minnesota, United States of America
| | - Rachel I. Vogel
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Joel W. Slaton
- Department of Urology, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Betsy T. Kren
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, United States of America
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Medicine, University of Minnesota, Minneapolis, Minnesota, United States of America
| | - Khalil Ahmed
- Research Service, Minneapolis VA Health Care System, Minneapolis, Minnesota, United States of America
- Department of Laboratory Medicine and Pathology, University of Minnesota, Minneapolis, Minnesota, United States of America
- Masonic Cancer Center, University of Minnesota, Minneapolis, Minnesota, United States of America
- Department of Urology, University of Minnesota, Minneapolis, Minnesota, United States of America
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25
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Skotte NH, Southwell AL, Østergaard ME, Carroll JB, Warby SC, Doty CN, Petoukhov E, Vaid K, Kordasiewicz H, Watt AT, Freier SM, Hung G, Seth PP, Bennett CF, Swayze EE, Hayden MR. Allele-specific suppression of mutant huntingtin using antisense oligonucleotides: providing a therapeutic option for all Huntington disease patients. PLoS One 2014; 9:e107434. [PMID: 25207939 PMCID: PMC4160241 DOI: 10.1371/journal.pone.0107434] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 08/11/2014] [Indexed: 01/10/2023] Open
Abstract
Huntington disease (HD) is an inherited, fatal neurodegenerative disorder caused by a CAG repeat expansion in the huntingtin gene. The mutant protein causes neuronal dysfunction and degeneration resulting in motor dysfunction, cognitive decline, and psychiatric disturbances. Currently, there is no disease altering treatment, and symptomatic therapy has limited benefit. The pathogenesis of HD is complicated and multiple pathways are compromised. Addressing the problem at its genetic root by suppressing mutant huntingtin expression is a promising therapeutic strategy for HD. We have developed and evaluated antisense oligonucleotides (ASOs) targeting single nucleotide polymorphisms that are significantly enriched on HD alleles (HD-SNPs). We describe our structure-activity relationship studies for ASO design and find that adjusting the SNP position within the gap, chemical modifications of the wings, and shortening the unmodified gap are critical for potent, specific, and well tolerated silencing of mutant huntingtin. Finally, we show that using two distinct ASO drugs targeting the two allelic variants of an HD-SNP could provide a therapeutic option for all persons with HD; allele-specifically for roughly half, and non-specifically for the remainder.
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Affiliation(s)
- Niels H. Skotte
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Amber L. Southwell
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Jeffrey B. Carroll
- Behavioral Neuroscience Program, Department of Psychology, Western Washington University, Bellingham, Washington, United States of America
| | - Simon C. Warby
- Center for Advanced Research in Sleep Medicine, Department of Psychiatry, University of Montréal, Montréal, Quebec, Canada
| | - Crystal N. Doty
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eugenia Petoukhov
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kuljeet Vaid
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
| | | | - Andrew T. Watt
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Susan M. Freier
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Gene Hung
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Punit P. Seth
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - C. Frank Bennett
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Eric E. Swayze
- ISIS Pharmaceuticals, Carlsbad, California, United States of America
| | - Michael R. Hayden
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, University of British Columbia, Vancouver, British Columbia, Canada
- * E-mail:
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26
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Hu J, Liu J, Narayanannair KJ, Lackey JG, Kuchimanchi S, Rajeev KG, Manoharan M, Swayze EE, Lima WF, Prakash TP, Xiang Q, Martinez C, Corey DR. Allele-selective inhibition of mutant atrophin-1 expression by duplex and single-stranded RNAs. Biochemistry 2014; 53:4510-8. [PMID: 24981774 PMCID: PMC4108179 DOI: 10.1021/bi500610r] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
![]()
Dentatorubral-pallidoluysian
atrophy (DRPLA) is a progressive neurodegenerative
disorder that currently has no curative treatments. DRPLA is caused
by an expansion of a CAG trinucleotide repeat region within the protein-encoding
sequence of the atrophin-1 (ATN-1) gene. Inhibition
of mutant ATN-1 protein expression is one strategy for treating DRPLA,
and allele-selective gene silencing agents that block mutant expression
over wild-type expression would be lead compounds for therapeutic
development. Here we develop an assay for distinguishing mutant from
wild-type ATN-1 protein by gel electrophoresis. We use this assay
to evaluate duplex RNAs and single-stranded silencing RNAs (ss-siRNAs)
for allele-selective inhibition of ATN-1 protein expression. We observed
potent and allele-selective inhibition by RNA duplexes that contain
mismatched bases relative to the CAG target and have the potential
to form miRNA-like complexes. ss-siRNAs that contained mismatches
were as selective as mismatch-containing duplexes. We also report
allele-selective inhibition by duplex RNAs containing unlocked nucleic
acids or abasic substitutions, although selectivities are not as high.
Five compounds that showed >8-fold allele selectivity for mutant ATN-1 were also selective for inhibiting the expression
of two other trinucleotide repeat disease genes, ataxin-3 (ATXN-3) and huntingtin (HTT). These data
demonstrate that the expanded trinucleotide repeat within ATN-1 mRNA is a potential target for compounds designed
to achieve allele-selective inhibition of ATN-1 protein, and one agent
may allow the targeting of multiple disease genes.
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Affiliation(s)
- Jiaxin Hu
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center , 6001 Forest Park Road, Dallas, Texas 75390-9041, United States
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27
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Chak LL, Okamura K. Argonaute-dependent small RNAs derived from single-stranded, non-structured precursors. Front Genet 2014; 5:172. [PMID: 24959173 PMCID: PMC4050365 DOI: 10.3389/fgene.2014.00172] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/22/2014] [Indexed: 12/31/2022] Open
Abstract
A general feature of Argonaute-dependent small RNAs is their base-paired precursor structures, and precursor duplex structures are often required for confident annotation of miRNA genes. However, this rule has been broken by discoveries of functional small RNA species whose precursors lack a predictable double-stranded (ds-) RNA structure, arguing that duplex structures are not prerequisite for small RNA loading to Argonautes. The biological significance of single-stranded (ss-) RNA loading has been recognized particularly in systems where active small RNA amplification mechanisms are involved, because even a small amount of RNA molecules can trigger the production of abundant RNA species leading to profound biological effects. However, even in the absence of small RNA amplification mechanisms, recent studies have demonstrated that potent gene silencing can be achieved using chemically modified synthetic ssRNAs that are resistant to RNases in mice. Therefore, such ssRNA-mediated gene regulation may have broader roles than previously recognized, and the findings have opened the door for further research to optimize the design of ss-siRNAs toward future pharmaceutical and biomedical applications of gene silencing technologies. In this review, we will summarize studies about endogenous ssRNA species that are bound by Argonaute proteins and how ssRNA precursors are recognized by various small RNA pathways.
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Affiliation(s)
- Li-Ling Chak
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore Singapore, Singapore
| | - Katsutomo Okamura
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore Singapore, Singapore ; School of Biological Sciences, Nanyang Technological University Singapore, Singapore
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28
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Evers MM, Toonen LJA, van Roon-Mom WMC. Ataxin-3 protein and RNA toxicity in spinocerebellar ataxia type 3: current insights and emerging therapeutic strategies. Mol Neurobiol 2014; 49:1513-31. [PMID: 24293103 PMCID: PMC4012159 DOI: 10.1007/s12035-013-8596-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/14/2013] [Indexed: 01/10/2023]
Abstract
Ataxin-3 is a ubiquitously expressed deubiqutinating enzyme with important functions in the proteasomal protein degradation pathway and regulation of transcription. The C-terminus of the ataxin-3 protein contains a polyglutamine (PolyQ) region that, when mutationally expanded to over 52 glutamines, causes the neurodegenerative disease spinocerebellar ataxia 3 (SCA3). In spite of extensive research, the molecular mechanisms underlying the cellular toxicity resulting from mutant ataxin-3 remain elusive and no preventive treatment is currently available. It has become clear over the last decade that the hallmark intracellular ataxin-3 aggregates are likely not the main toxic entity in SCA3. Instead, the soluble PolyQ containing fragments arising from proteolytic cleavage of ataxin-3 by caspases and calpains are now regarded to be of greater influence in pathogenesis. In addition, recent evidence suggests potential involvement of a RNA toxicity component in SCA3 and other PolyQ expansion disorders, increasing the pathogenic complexity. Herein, we review the functioning of ataxin-3 and the involvement of known protein and RNA toxicity mechanisms of mutant ataxin-3 that have been discovered, as well as future opportunities for therapeutic intervention.
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Affiliation(s)
- Melvin M. Evers
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Lodewijk J. A. Toonen
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
| | - Willeke M. C. van Roon-Mom
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333ZA Leiden, The Netherlands
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29
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Fiszer A, Krzyzosiak WJ. Oligonucleotide-based strategies to combat polyglutamine diseases. Nucleic Acids Res 2014; 42:6787-810. [PMID: 24848018 PMCID: PMC4066792 DOI: 10.1093/nar/gku385] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Considerable advances have been recently made in understanding the molecular aspects of pathogenesis and in developing therapeutic approaches for polyglutamine (polyQ) diseases. Studies on pathogenic mechanisms have extended our knowledge of mutant protein toxicity, confirmed the toxicity of mutant transcript and identified other toxic RNA and protein entities. One very promising therapeutic strategy is targeting the causative gene expression with oligonucleotide (ON) based tools. This straightforward approach aimed at halting the early steps in the cascade of pathogenic events has been widely tested for Huntington's disease and spinocerebellar ataxia type 3. In this review, we gather information on the use of antisense oligonucleotides and RNA interference triggers for the experimental treatment of polyQ diseases in cellular and animal models. We present studies testing non-allele-selective and allele-selective gene silencing strategies. The latter include targeting SNP variants associated with mutations or targeting the pathologically expanded CAG repeat directly. We compare gene silencing effectors of various types in a number of aspects, including their design, efficiency in cell culture experiments and pre-clinical testing. We discuss advantages, current limitations and perspectives of various ON-based strategies used to treat polyQ diseases.
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Affiliation(s)
- Agnieszka Fiszer
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
| | - Wlodzimierz J Krzyzosiak
- Department of Molecular Biomedicine, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznan, Poland
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30
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Hu J, Liu J, Yu D, Aiba Y, Lee S, Pendergraff H, Boubaker J, Artates JW, Lagier-Tourenne C, Lima WF, Swayze EE, Prakash TP, Corey DR. Exploring the effect of sequence length and composition on allele-selective inhibition of human huntingtin expression by single-stranded silencing RNAs. Nucleic Acid Ther 2014; 24:199-209. [PMID: 24694346 DOI: 10.1089/nat.2013.0476] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Mutant huntingtin (HTT) protein is the cause of Huntington's disease (HD), an incurable neurological disorder. Almost all patients are heterozygous for mutant HTT and approaches that reduce levels of mutant HTT while leaving expression of wild-type HTT intact might be ideal options for therapeutic development. We have developed several allele-selective strategies for silencing HTT, including single-stranded silencing RNAs (ss-siRNAs). ss-siRNAs are oligonucleotides containing chemical modifications that permit action through the RNA interference (RNAi) pathway. Modified ss-siRNAs chosen to test the effects of varying oligomer length, lipid modification, the introduction of mismatched bases, and variation of chemical modification. We find that several modified ss-siRNA are potent and allele-selective inhibitors of HTT expression. An ss-siRNA with three mismatched bases relative to the CAG repeat was an allele-selective inhibitor of HTT expression in the HdhQ175 mouse model. Multiple allele-selective ss-siRNAs provide a wide platform of modifications to draw on for further optimization and therapeutic development. Our data provide insights into how ss-siRNAs can be modified to improve their properties and facilitate the discovery of the lead compounds necessary for further development.
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Affiliation(s)
- Jiaxin Hu
- 1 Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center at Dallas , Dallas, Texas
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31
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Aiba Y, Hu J, Liu J, Xiang Q, Martinez C, Corey DR. Allele-selective inhibition of expression of huntingtin and ataxin-3 by RNA duplexes containing unlocked nucleic acid substitutions. Biochemistry 2013; 52:9329-38. [PMID: 24266403 DOI: 10.1021/bi4014209] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Unlocked nucleic acid (UNA) is an acyclic analogue of RNA that can be introduced into RNA or DNA oligonucleotides. The increased flexibility conferred by the acyclic structure fundamentally affects the strength of base pairing, creating opportunities for improved applications and new insights into molecular recognition. Here we test how UNA substitutions affect allele-selective inhibition of expression of trinucleotide repeat genes Huntingtin (HTT) and Ataxin-3 (ATX-3). We find that the either the combination of mismatched bases and UNA substitutions or UNA substitutions alone can improve potency and selectivity. Inhibition is potent, and selectivities of >40-fold for inhibiting mutant versus wild-type expression can be achieved. Surprisingly, even though UNA preserves the potential for complete base pairing, the introduction of UNA substitutions at central positions within fully complementary duplexes leads to >19-fold selectivity. Like mismatched bases, the introduction of central UNA bases disrupts the potential for cleavage of substrate by argonaute 2 (AGO2) during gene silencing. UNA-substituted duplexes are as effective as other strategies for allele-selective silencing of trinucleotide repeat disease genes. Modulation of AGO2 activity by the introduction of UNA substitutions demonstrates that backbone flexibility is as important as base pairing for catalysis of fully complementary duplex substrates. UNA can be used to tailor RNA silencing for optimal properties and allele-selective action.
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Affiliation(s)
- Yuichiro Aiba
- Departments of Pharmacology and Biochemistry, University of Texas Southwestern Medical Center , 6001 Forest Park Road, Dallas, Texas 75390-9041, United States
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