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Sioud M, Juzeniene A, Sæbøe-Larssen S. Exploring the Impact of mRNA Modifications on Translation Efficiency and Immune Tolerance to Self-Antigens. Vaccines (Basel) 2024; 12:624. [PMID: 38932353 PMCID: PMC11209393 DOI: 10.3390/vaccines12060624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2024] [Revised: 06/02/2024] [Accepted: 06/03/2024] [Indexed: 06/28/2024] Open
Abstract
Therapeutic modified mRNAs are being developed for a broad range of human diseases. However, the impact of potential miscoding of modified mRNAs on self-tolerance remains unknown. Additionally, more studies are needed to explore the effects of nucleoside alkylation on translation. While all six tested modifications are tolerated as substrates by T7 RNA polymerase and inhibited mRNA immunogenicity, the translation efficiency varied significantly depending on the type of modification. In contrast to methylation, ethylation at the N1 position of pseudouridine (Ψ) hindered translation, suggesting that the C5-C1' glycosidic bond alone is not a critical element for high translation. Inhibition of mRNA translation was also observed with 5-methoxyuridine modification. However, this inhibition was partially alleviated through the optimization of mRNA coding sequences. BALB/c mice immunized with syngeneic ψ-modified mRNA encoding for Wilms' tumor antigen-1 (WT1) developed a low but significant level of anti-WT1 IgG antibodies compared to those immunized with either unmodified or N1-methyl ψ-modified mRNA. Overall, the data indicate that adding a simple ethyl group (-CH2CH3) at the N1 position of ψ has a major negative effect on translation despite its reduced immunogenicity. Additionally, mRNA containing Ψ may alter translation fidelity at certain codons, which could lead to a breakdown of immune tolerance to self-antigens. This concern should be taken into account during gene replacement therapies, although it could benefit mRNA-based vaccines by generating a diverse repertoire of antigens.
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Affiliation(s)
- Mouldy Sioud
- Department of Cancer Immunology, Oslo University Hospital, Radiumhospitalet, Ullernchausseen 70, 0379 Oslo, Norway
| | - Asta Juzeniene
- Department of Radiation Biology, Oslo University Hospital, Radiumhospitalet, Ullernchausseen 70, 0379 Oslo, Norway;
| | - Stein Sæbøe-Larssen
- Department of cellular Therapy, Oslo University Hospital, Radiumhospitalet, Ullernchausseen 70, 0379 Oslo, Norway;
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Patange S, Maragh S. Fire Burn and Cauldron Bubble: What Is in Your Genome Editing Brew? Biochemistry 2023; 62:3500-3511. [PMID: 36306429 PMCID: PMC10734218 DOI: 10.1021/acs.biochem.2c00431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 09/28/2022] [Indexed: 11/28/2022]
Abstract
Genome editing is a rapidly evolving biotechnology with the potential to transform many sectors of industry such as agriculture, biomanufacturing, and medicine. This technology is enabled by an ever-growing portfolio of biomolecular reagents that span the central dogma, from DNA to RNA to protein. In this paper, we draw from our unique perspective as the National Metrology Institute of the United States to bring attention to the importance of understanding and reporting genome editing formulations accurately and promoting concepts to verify successful delivery into cells. Achieving the correct understanding may be hindered by the way units, quantities, and stoichiometries are reported in the field. We highlight the variability in how editing formulations are reported in the literature and examine how a reference molecule could be used to verify the delivery of a reagent into cells. We provide recommendations on how more accurate reporting of editing formulations and more careful verification of the steps in an editing experiment can help set baseline expectations of reagent performance, toward the aim of enabling genome editing studies to be more reproducible. We conclude with a future outlook on technologies that can further our control and enable our understanding of genome editing outcomes at the single-cell level.
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Affiliation(s)
- Simona Patange
- Biosystems and Biomaterials
Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
| | - Samantha Maragh
- Biosystems and Biomaterials
Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
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Allen D, Rosenberg M, Hendel A. Using Synthetically Engineered Guide RNAs to Enhance CRISPR Genome Editing Systems in Mammalian Cells. Front Genome Ed 2021; 2:617910. [PMID: 34713240 PMCID: PMC8525374 DOI: 10.3389/fgeed.2020.617910] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 12/14/2020] [Indexed: 12/26/2022] Open
Abstract
CRISPR-Cas9 is quickly revolutionizing the way we approach gene therapy. CRISPR-Cas9 is a complexed, two-component system using a short guide RNA (gRNA) sequence to direct the Cas9 endonuclease to the target site. Modifying the gRNA independent of the Cas9 protein confers ease and flexibility to improve the CRISPR-Cas9 system as a genome-editing tool. gRNAs have been engineered to improve the CRISPR system's overall stability, specificity, safety, and versatility. gRNAs have been modified to increase their stability to guard against nuclease degradation, thereby enhancing their efficiency. Additionally, guide specificity has been improved by limiting off-target editing. Synthetic gRNA has been shown to ameliorate inflammatory signaling caused by the CRISPR system, thereby limiting immunogenicity and toxicity in edited mammalian cells. Furthermore, through conjugation with exogenous donor DNA, engineered gRNAs have been shown to improve homology-directed repair (HDR) efficiency by ensuring donor proximity to the edited site. Lastly, synthetic gRNAs attached to fluorescent labels have been developed to enable highly specific nuclear staining and imaging, enabling mechanistic studies of chromosomal dynamics and genomic mapping. Continued work on chemical modification and optimization of synthetic gRNAs will undoubtedly lead to clinical and therapeutic benefits and, ultimately, routinely performed CRISPR-based therapies.
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Affiliation(s)
- Daniel Allen
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Michael Rosenberg
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
| | - Ayal Hendel
- Institute of Nanotechnology and Advanced Materials, The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan, Israel
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Vasquez G, Migawa MT, Wan WB, Low A, Tanowitz M, Swayze EE, Seth PP. Evaluation of Phosphorus and Non-Phosphorus Neutral Oligonucleotide Backbones for Enhancing Therapeutic Index of Gapmer Antisense Oligonucleotides. Nucleic Acid Ther 2021; 32:40-50. [PMID: 34698585 DOI: 10.1089/nat.2021.0064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The phosphorothioate (PS) linkage in an essential component of therapeutic oligonucleotides. PS in the DNA region of gapmer antisense oligonucleotides (ASOs) supports RNaseH1 activity and enhances nuclease stability. PS also promotes binding to plasma, cell surface, and intracellular proteins, which facilitates tissue distribution, cellular uptake, and endosomal escape of PS ASOs. We recently showed that site-specific replacement of PS in the DNA gap with methoxylpropyl phosphonate (MOP) linkages can enhance the therapeutic index of gapmer ASOs. In this article, we explored 18 phosphorus- and non-phosphorus-based neutral backbone modifications to determine the structure-activity relationship of neutral linkages for enhancing therapeutic index. Replacing MOP with other alkyl phosphonate and phosphotriester linkages enhanced therapeutic index, but these linkages were susceptible to chemical degradation during oligonucleotide deprotection from solid supports following synthesis. Replacing MOP with non-phosphorus linkages resulted in improved chemical stability, but these linkages were introduced into ASOs as nucleotide dimers, which limits their versatility. Overall, linkages such as isopropyl and isobutyl phosphonates and O-isopropyl and O-tetrahydrofuranosyl phosphotriesters, formacetal, and C3-amide showed improved activity in mice relative to MOP. Our data suggest that site-specific incorporation of any neutral backbone linkage can improve therapeutic index, but the size, hydrophobicity, and RNA-binding affinity of the linkage influence ASO activity.
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Affiliation(s)
- Guillermo Vasquez
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Michael T Migawa
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - W Brad Wan
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Audrey Low
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Michael Tanowitz
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Eric E Swayze
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
| | - Punit P Seth
- Department of Medicinal Chemistry, Ionis Pharmaceuticals, Carlsbad, California, USA
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González Castro N, Bjelic J, Malhotra G, Huang C, Alsaffar SH. Comparison of the Feasibility, Efficiency, and Safety of Genome Editing Technologies. Int J Mol Sci 2021; 22:10355. [PMID: 34638696 PMCID: PMC8509008 DOI: 10.3390/ijms221910355] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 08/26/2021] [Accepted: 09/24/2021] [Indexed: 12/15/2022] Open
Abstract
Recent advances in programmable nucleases including meganucleases (MNs), zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats-Cas (CRISPR-Cas) have propelled genome editing from explorative research to clinical and industrial settings. Each technology, however, features distinct modes of action that unevenly impact their applicability across the entire genome and are often tested under significantly different conditions. While CRISPR-Cas is currently leading the field due to its versatility, quick adoption, and high degree of support, it is not without limitations. Currently, no technology can be regarded as ideal or even applicable to every case as the context dictates the best approach for genetic modification within a target organism. In this review, we implement a four-pillar framework (context, feasibility, efficiency, and safety) to assess the main genome editing platforms, as a basis for rational decision-making by an expanding base of users, regulators, and consumers. Beyond carefully considering their specific use case with the assessment framework proposed here, we urge stakeholders interested in genome editing to independently validate the parameters of their chosen platform prior to commitment. Furthermore, safety across all applications, particularly in clinical settings, is a paramount consideration and comprehensive off-target detection strategies should be incorporated within workflows to address this. Often neglected aspects such as immunogenicity and the inadvertent selection of mutants deficient for DNA repair pathways must also be considered.
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Affiliation(s)
- Nicolás González Castro
- School of Biosciences, Faculty of Science, University of Melbourne, Parkville 3052, Australia; (N.G.C.); (G.M.); (C.H.); (S.H.A.)
| | - Jan Bjelic
- School of Biosciences, Faculty of Science, University of Melbourne, Parkville 3052, Australia; (N.G.C.); (G.M.); (C.H.); (S.H.A.)
| | - Gunya Malhotra
- School of Biosciences, Faculty of Science, University of Melbourne, Parkville 3052, Australia; (N.G.C.); (G.M.); (C.H.); (S.H.A.)
| | - Cong Huang
- School of Biosciences, Faculty of Science, University of Melbourne, Parkville 3052, Australia; (N.G.C.); (G.M.); (C.H.); (S.H.A.)
| | - Salman Hasan Alsaffar
- School of Biosciences, Faculty of Science, University of Melbourne, Parkville 3052, Australia; (N.G.C.); (G.M.); (C.H.); (S.H.A.)
- Biotechnology Department, Environment and Life Sciences Research Center, Kuwait Institute for Scientific Research, Shuwaikh 13109, Kuwait
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Chen Q, Zhang Y, Yin H. Recent advances in chemical modifications of guide RNA, mRNA and donor template for CRISPR-mediated genome editing. Adv Drug Deliv Rev 2021; 168:246-258. [PMID: 33122087 DOI: 10.1016/j.addr.2020.10.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 10/19/2020] [Accepted: 10/21/2020] [Indexed: 12/14/2022]
Abstract
The discovery and applications of clustered regularly interspaced short palindromic repeat (CRISPR) systems have revolutionized our ability to track and manipulate specific nucleic acid sequences in many cell types of various organisms. The robustness and simplicity of these platforms have rapidly extended their applications from basic research to the development of therapeutics. However, many hurdles remain on the path to translation of the CRISPR systems to therapeutic applications: efficient delivery, detectable off-target effects, potential immunogenicity, and others. Chemical modifications provide a variety of protection options for guide RNA, Cas9 mRNA and donor templates. For example, chemically modified gRNA demonstrated enhanced on-target editing efficiency, minimized immune response and decreased off-target genome editing. In this review, we summarize the use of chemically modified nucleotides for CRISPR-mediated genome editing and emphasize open questions that remain to be addressed in clinical applications.
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Affiliation(s)
- Qiubing Chen
- Department of Urology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China; Department of Pathology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China
| | - Ying Zhang
- Medical Research Institute, Renmin Hospital of Wuhan University, Wuhan University, Wuhan, China.
| | - Hao Yin
- Department of Urology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China; Department of Pathology, Frontier Science Center for Immunology and Metabolism, Medical Research Institute, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan 430071, China.
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