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Choi DE, Shin JW, Zeng S, Hong EP, Jang JH, Loupe JM, Wheeler VC, Stutzman HE, Kleinstiver B, Lee JM. Base editing strategies to convert CAG to CAA diminish the disease-causing mutation in Huntington's disease. eLife 2024; 12:RP89782. [PMID: 38869243 PMCID: PMC11175616 DOI: 10.7554/elife.89782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2024] Open
Abstract
An expanded CAG repeat in the huntingtin gene (HTT) causes Huntington's disease (HD). Since the length of uninterrupted CAG repeat, not polyglutamine, determines the age-at-onset in HD, base editing strategies to convert CAG to CAA are anticipated to delay onset by shortening the uninterrupted CAG repeat. Here, we developed base editing strategies to convert CAG in the repeat to CAA and determined their molecular outcomes and effects on relevant disease phenotypes. Base editing strategies employing combinations of cytosine base editors and guide RNAs (gRNAs) efficiently converted CAG to CAA at various sites in the CAG repeat without generating significant indels, off-target edits, or transcriptome alterations, demonstrating their feasibility and specificity. Candidate BE strategies converted CAG to CAA on both expanded and non-expanded CAG repeats without altering HTT mRNA and protein levels. In addition, somatic CAG repeat expansion, which is the major disease driver in HD, was significantly decreased in the liver by a candidate BE strategy treatment in HD knock-in mice carrying canonical CAG repeats. Notably, CAG repeat expansion was abolished entirely in HD knock-in mice carrying CAA-interrupted repeats, supporting the therapeutic potential of CAG-to-CAA conversion strategies in HD and potentially other repeat expansion disorders.
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Affiliation(s)
- Doo Eun Choi
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Jun Wan Shin
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Sophia Zeng
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
| | - Eun Pyo Hong
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
- Medical and Population Genetics Program, The Broad Institute of MIT and HarvardCambridgeUnited States
| | - Jae-Hyun Jang
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Jacob M Loupe
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Vanessa C Wheeler
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
| | - Hannah E Stutzman
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Massachusetts General HospitalBostonUnited States
| | - Ben Kleinstiver
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Massachusetts General HospitalBostonUnited States
- Department of Pathology, Harvard Medical SchoolBostonUnited States
| | - Jong-Min Lee
- Center for Genomic Medicine, Massachusetts General HospitalBostonUnited States
- Department of Neurology, Harvard Medical SchoolBostonUnited States
- Medical and Population Genetics Program, The Broad Institute of MIT and HarvardCambridgeUnited States
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McFarland KN, Tiwari A, Hashem V, Zhang L, Zeng D, Vincent J, Arredondo MJ, Johnson KL, Gan SR, Yabe I, Skov L, Rasmussen A, Ashizawa T. Extended haplotype with rs41524547-G defines the ancestral origin of SCA10. Hum Mol Genet 2024:ddae092. [PMID: 38832639 DOI: 10.1093/hmg/ddae092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 05/20/2024] [Indexed: 06/05/2024] Open
Abstract
Spinocerebellar ataxia type 10 (SCA10) is a rare autosomal dominant ataxia caused by a large expansion of the (ATTCT)n repeat in ATXN10. SCA10 was described in Native American and Asian individuals which prompted a search for an expanded haplotype to confirm a common ancestral origin for the expansion event. All patients with SCA10 expansions in our cohort share a single haplotype defined at the 5'-end by the minor allele of rs41524547, located ~35 kb upstream of the SCA10 expansion. Intriguingly, rs41524547 is located within the miRNA gene, MIR4762, within its DROSHA cleavage site and just outside the seed sequence for mir4792-5p. The world-wide frequency of rs41524547-G is less than 5% and found almost exclusively in the Americas and East Asia-a geographic distribution that mirrors reported SCA10 cases. We identified rs41524547-G(+) DNA from the 1000 Genomes/International Genome Sample Resource and our own general population samples and identified SCA10 repeat expansions in up to 25% of these samples. The reduced penetrance of these SCA10 expansions may be explained by a young (pre-onset) age at sample collection, a small repeat size, purity of repeat units, or the disruption of miR4762-5p function. We conclude that rs41524547-G is the most robust at-risk SNP allele for SCA10, is useful for screening of SCA10 expansions in population genetics studies and provides the most compelling evidence to date for a single, prehistoric origin of SCA10 expansions sometime prior to or during the migration of individuals across the Bering Land Bridge into the Americas.
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Affiliation(s)
- Karen N McFarland
- Department of Neurology, College of Medicine, The McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, United States
- Center for Translational Research in Neurodegeneration, University of Florida, 1275 Center Drive, Gainesville, FL 32610, United States
| | - Anjana Tiwari
- Neuroscience Research Program and Department of Neurology, Houston Methodist Hospital and Weill Cornell Medicine, 6560 Fannin Street, Houston, TX 77030, United States
| | - Vera Hashem
- Neuroscience Research Program and Department of Neurology, Houston Methodist Hospital and Weill Cornell Medicine, 6560 Fannin Street, Houston, TX 77030, United States
| | - Linwei Zhang
- Department of Neurology, China-Japan Friendship Hospital, Yinghua East Street 2, Chaoyang, Beijing 100029, China
| | - Desmond Zeng
- Department of Neurology, College of Medicine, The McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, United States
| | - Justin Vincent
- Neuroscience Research Program and Department of Neurology, Houston Methodist Hospital and Weill Cornell Medicine, 6560 Fannin Street, Houston, TX 77030, United States
| | - Maria J Arredondo
- Neuroscience Research Program and Department of Neurology, Houston Methodist Hospital and Weill Cornell Medicine, 6560 Fannin Street, Houston, TX 77030, United States
| | - Kristy L Johnson
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Shi Rui Gan
- Department of Neurology and Institute of Neurology, First Affiliated Hospital, Fujian Medical University, 20 Cha Zhong Lu, Tailing District, Fuzhou 362000, China
| | - Ichiro Yabe
- Department of Neurology, Faculty of Medicine and Graduate School of Medicine, Hokkaido University, 7 Chome Kita 15 Jonishi, Kita Ward, Sapporo 060-8638, Japan
| | - Laurits Skov
- Bioinformatics Research Centre, Aarhus University, Universitetsbyen 81, 3., Building 1872, Aarhus C. DK-8000, Denmark
| | - Astrid Rasmussen
- Genes and Human Disease Research Program, Oklahoma Medical Research Foundation, 825 N.E. 13th Street, Oklahoma City, Oklahoma 73104, United States
| | - Tetsuo Ashizawa
- Department of Neurology, College of Medicine, The McKnight Brain Institute, University of Florida, 1149 South Newell Drive, Gainesville, FL 32610, United States
- Neuroscience Research Program and Department of Neurology, Houston Methodist Hospital and Weill Cornell Medicine, 6560 Fannin Street, Houston, TX 77030, United States
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Choi DE, Shin JW, Zeng S, Hong EP, Jang JH, Loupe JM, Wheeler VC, Stutzman HE, Kleinstiver BP, Lee JM. Base editing strategies to convert CAG to CAA diminish the disease-causing mutation in Huntington's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.28.538700. [PMID: 37162872 PMCID: PMC10168301 DOI: 10.1101/2023.04.28.538700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
An expanded CAG repeat in the huntingtin gene ( HTT ) causes Huntington's disease (HD). Since the length of uninterrupted CAG repeat, not polyglutamine, determines the age-at-onset in HD, base editing strategies to convert CAG to CAA are anticipated to delay onset by shortening the uninterrupted CAG repeat. Here, we developed base editing strategies to convert CAG in the repeat to CAA and determined their molecular outcomes and effects on relevant disease phenotypes. Base editing strategies employing combinations of cytosine base editors and gRNAs efficiently converted CAG to CAA at various sites in the CAG repeat without generating significant indels, off-target edits, or transcriptome alterations, demonstrating their feasibility and specificity. Candidate BE strategies converted CAG to CAA on both expanded and non-expanded CAG repeats without altering HTT mRNA and protein levels. In addition, somatic CAG repeat expansion, which is the major disease driver in HD, was significantly decreased by a candidate BE strategy treatment in HD knock-in mice carrying canonical CAG repeats. Notably, CAG repeat expansion was abolished entirely in HD knock-in mice carrying CAA-interrupted repeats, supporting the therapeutic potential of CAG-to-CAA conversion base editing strategies in HD and potentially other repeat expansion disorders.
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Chrysostomou AC, Aristokleous A, Rodosthenous JH, Christodoulou C, Stathi G, Kostrikis LG. Detection of Circulating SARS-CoV-2 Variants of Concern (VOCs) Using a Multiallelic Spectral Genotyping Assay. Life (Basel) 2023; 13:life13020304. [PMID: 36836661 PMCID: PMC9960118 DOI: 10.3390/life13020304] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/17/2023] [Accepted: 01/19/2023] [Indexed: 01/24/2023] Open
Abstract
Throughout the coronavirus disease 2019 (COVID-19) pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has continuously evolved, resulting in new variants, some of which possess increased infectivity, immune evasion, and virulence. Such variants have been denoted by the World Health Organization as variants of concern (VOC) because they have resulted in an increased number of cases, posing a strong risk to public health. Thus far, five VOCs have been designated, Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Delta (B.1.617.2), and Omicron (B.1.1.529), including their sublineages. Next-generation sequencing (NGS) can produce a significant amount of information facilitating the study of variants; however, NGS is time-consuming and costly and not efficient during outbreaks, when rapid identification of VOCs is urgently needed. In such periods, there is a need for fast and accurate methods, such as real-time reverse transcription PCR in combination with probes, which can be used for monitoring and screening of the population for these variants. Thus, we developed a molecular beacon-based real-time RT-PCR assay according to the principles of spectral genotyping. This assay employs five molecular beacons that target ORF1a:ΔS3675/G3676/F3677, S:ΔH69/V70, S:ΔE156/F157, S:ΔΝ211, S:ins214EPE, and S:ΔL242/A243/L244, deletions and an insertion found in SARS-CoV-2 VOCs. This assay targets deletions/insertions because they inherently provide higher discrimination capacity. Here, the design process of the molecular beacon-based real-time RT-PCR assay for detection and discrimination of SARS-CoV-2 is presented, and experimental testing using SARS-CoV-2 VOC samples from reference strains (cultured virus) and clinical patient samples (nasopharyngeal samples), which have been previously classified using NGS, were evaluated. Based on the results, it was shown that all molecular beacons can be used under the same real-time RT-PCR conditions, consequently improving the time and cost efficiency of the assay. Furthermore, this assay was able to confirm the genotype of each of the tested samples from various VOCs, thereby constituting an accurate and reliable method for VOC detection and discrimination. Overall, this assay is a valuable tool that can be used for screening and monitoring the population for VOCs or other emerging variants, contributing to limiting their spread and protecting public health.
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Affiliation(s)
| | - Antonia Aristokleous
- Department of Biological Sciences, University of Cyprus, Aglantzia, 2109 Nicosia, Cyprus
| | | | | | - Georgia Stathi
- Department of Biological Sciences, University of Cyprus, Aglantzia, 2109 Nicosia, Cyprus
| | - Leondios G. Kostrikis
- Department of Biological Sciences, University of Cyprus, Aglantzia, 2109 Nicosia, Cyprus
- Cyprus Academy of Sciences, Letters, and Arts, 60-68 Phaneromenis Street, 1011 Nicosia, Cyprus
- Correspondence: ; Tel.: +35-72-289-2885
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Helm J, Schöls L, Hauser S. Towards Personalized Allele-Specific Antisense Oligonucleotide Therapies for Toxic Gain-of-Function Neurodegenerative Diseases. Pharmaceutics 2022; 14:pharmaceutics14081708. [PMID: 36015334 PMCID: PMC9416334 DOI: 10.3390/pharmaceutics14081708] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 08/11/2022] [Accepted: 08/12/2022] [Indexed: 11/29/2022] Open
Abstract
Antisense oligonucleotides (ASOs) are single-stranded nucleic acid strings that can be used to selectively modify protein synthesis by binding complementary (pre-)mRNA sequences. By specific arrangements of DNA and RNA into a chain of nucleic acids and additional modifications of the backbone, sugar, and base, the specificity and functionality of the designed ASOs can be adjusted. Thereby cellular uptake, toxicity, and nuclease resistance, as well as binding affinity and specificity to its target (pre-)mRNA, can be modified. Several neurodegenerative diseases are caused by autosomal dominant toxic gain-of-function mutations, which lead to toxic protein products driving disease progression. ASOs targeting such mutations—or even more comprehensively, associated variants, such as single nucleotide polymorphisms (SNPs)—promise a selective degradation of the mutant (pre-)mRNA while sparing the wild type allele. By this approach, protein expression from the wild type strand is preserved, and side effects from an unselective knockdown of both alleles can be prevented. This makes allele-specific targeting strategies a focus for future personalized therapies. Here, we provide an overview of current strategies to develop personalized, allele-specific ASO therapies for the treatment of neurodegenerative diseases, such Huntington’s disease (HD) and spinocerebellar ataxia type 3 (SCA3/MJD).
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Affiliation(s)
- Jacob Helm
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
- Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, 72076 Tübingen, Germany
| | - Ludger Schöls
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
| | - Stefan Hauser
- German Center for Neurodegenerative Diseases (DZNE), 72076 Tübingen, Germany
- Hertie Institute for Clinical Brain Research and Department of Neurology, University of Tübingen, 72076 Tübingen, Germany
- Correspondence:
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