1
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Qulsum U, Azad MTA, Kato K. Efficacy of medicinal plants and their derived biomolecules against Plasmodium falciparum. Parasitol Int 2024; 103:102946. [PMID: 39128649 DOI: 10.1016/j.parint.2024.102946] [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: 02/09/2024] [Revised: 07/12/2024] [Accepted: 08/08/2024] [Indexed: 08/13/2024]
Abstract
Many apicomplexan pathogens pose significant threats to humans and domestic animals, with the lack of effective drugs and drug resistance representing major challenges in disease management. To address this, the search for new and potent antimalarial drugs is crucial. Plant-based formulations offer a promising alternative for such drug development. Here, we evaluated the in vitro antiplasmodial activity of nine plant extracts, traditionally used to treat fever-like symptoms in Bangladesh. We assessed the antimalarial activity of plant extracts by using the Plasmodium falciparum 3D7 growth inhibition assay, an invasion assay, and a cytotoxicity assay. Of the nine plants studied, ethanolic and methanolic leaf extracts of Ficus hispida, Streblus asper, and Boerhavia repens exhibited high antiplasmodial activity, with IC50 values of 9.31, 4.13, 9.63 μg/ml (ethanolic) and 15.12, 6.63, 7.58 μg/ml (methanolic), respectively, and minimal toxicity (cell viability >80%). Clerodendrum viscosum displayed antiplasmodial effects with IC50 values of 28.90 μg/ml (ethanolic) and 30.57 μg/ml (methanolic). Adhatoda vasica, Mussaenda corymbosa, and Amaranthus spinosus ethanolic extracts showed antimalarial effects with IC50 values of 61.78 μg/ml, 66.31 μg/ml, and 64.14 μg/ml, respectively. However, methanolic extracts of A. vasica and A. spinosus had IC50 values >100 μg/ml. The ethanolic and methanolic extracts of A. vasica, A. spinosus, F. hispida, S. asper, and B. repens significantly reduced parasitemia by inhibiting invasion into erythrocytes. This study highlights the robust antimalarial activity and low cytotoxicity of leaf extracts of F. hispida, S. asper, and B. repens, indicating the presence of antimalarial compounds that warrant further investigation.
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Affiliation(s)
- Umme Qulsum
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan; Department of Botany, Faculty of Biological Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Md Thoufic Anam Azad
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan; Department of Veterinary and Animal Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Kentaro Kato
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan.
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2
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Song J, Luo N, Dong L, Peng J, Yi C. RNA base editors: The emerging approach of RNA therapeutics. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1844. [PMID: 38576085 DOI: 10.1002/wrna.1844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 03/12/2024] [Accepted: 03/18/2024] [Indexed: 04/06/2024]
Abstract
RNA-based therapeutics offer a flexible and reversible approach for treating genetic disorders, such as antisense oligonucleotides, RNA interference, aptamers, mRNA vaccines, and RNA editing. In recent years, significant advancements have been made in RNA base editing to correct disease-relevant point mutations. These achievements have significantly influenced the fields of biotechnology, biomedical research and therapeutics development. In this article, we provide a comprehensive overview of the design and performance of contemporary RNA base editors, including A-to-I, C-to-U, A-to-m6A, and U-to-Ψ. We compare recent innovative developments and highlight their applications in disease-relevant contexts. Lastly, we discuss the limitations and future prospects of utilizing RNA base editing for therapeutic purposes. This article is categorized under: RNA Processing > RNA Editing and Modification RNA in Disease and Development > RNA in Development.
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Affiliation(s)
- Jinghui Song
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Nan Luo
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Liting Dong
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
| | - Jinying Peng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Beijing Advanced Center of RNA Biology (BEACON), Peking University, Beijing, China
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3
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Song J, Zhuang Y, Yi C. Programmable RNA base editing via targeted modifications. Nat Chem Biol 2024; 20:277-290. [PMID: 38418907 DOI: 10.1038/s41589-023-01531-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Accepted: 12/18/2023] [Indexed: 03/02/2024]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-based genome editors are powerful tools in biology and hold great promise for the treatment of human diseases. Advanced DNA base editing tools, such as cytosine base editor and adenine base editor, have been developed to correct permanent mistakes in genetic material. However, undesired off-target edits would also be permanent, which poses a considerable risk for therapeutics. Alternatively, base editing at the RNA level is capable of correcting disease-causing mutations but does not lead to lasting genotoxic effects. RNA base editors offer temporary and reversible therapies and have been catching on in recent years. Here, we summarize some emerging RNA editors based on A-to-inosine, C-to-U and U-to-pseudouridine changes. We review the programmable RNA-targeting systems as well as modification enzyme-based effector proteins and highlight recent technological breakthroughs. Finally, we compare editing tools, discuss limitations and opportunities, and provide insights for the future directions of RNA base editing.
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Affiliation(s)
- Jinghui Song
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, People's Republic of China
| | - Yuan Zhuang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, People's Republic of China
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, People's Republic of China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, People's Republic of China.
- Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, People's Republic of China.
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4
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Azad MTA, Sugi T, Qulsum U, Kato K. Detection of Developmental Asexual Stage-Specific RNA Editing Events in Plasmodium falciparum 3D7 Malaria Parasite. Microorganisms 2024; 12:137. [PMID: 38257964 PMCID: PMC10819399 DOI: 10.3390/microorganisms12010137] [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: 10/27/2023] [Revised: 12/24/2023] [Accepted: 12/30/2023] [Indexed: 01/24/2024] Open
Abstract
Transcriptional variation has been studied but post-transcriptional modification due to RNA editing has not been investigated in Plasmodium. We investigated developmental stage-specific RNA editing in selected genes in Plasmodium falciparum 3D7. We detected extensive amination- and deamination-type RNA editing at 8, 16, 24, 32, 40, and 46 h in tightly synchronized Plasmodium. Most of the editing events were observed in 8 and 16 h ring-stage parasites. Extensive A-to-G deamination-type editing was detected more during the 16 h ring stage (25%) than the 8 h ring stage (20%). Extensive U-to-C amination-type editing was detected more during the 16 h ring stage (31%) than the 8 h ring stage (22%). In 28S, rRNA editing converted the loop structure to the stem structure. The hemoglobin binding activity of PF3D7_0216900 was also altered due to RNA editing. Among the expressed 28S rRNA genes, PF3D7_0532000 and PF3D7_0726000 expression was higher. Increased amounts of the transcripts of these two genes were found, particularly PF3D7_0726000 in the ring stage and PF3D7_0532000 in the trophozoite and schizont stages. Adenosine deaminase (ADA) expression did not correlate with the editing level. This first experimental report of RNA editing will help to identify the editing machinery that might be useful for antimalarial drug discovery and malaria control.
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Affiliation(s)
- Md Thoufic Anam Azad
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan
- Department of Veterinary and Animal Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Tatsuki Sugi
- Division of Collaboration and Education, International Institute for Zoonosis Control, Hokkaido University, Nishi10-Kita 20, Sapporo 001-0020, Japan
| | - Umme Qulsum
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Kentaro Kato
- Laboratory of Sustainable Animal Environment, Graduate School of Agricultural Science, Tohoku University, 232-3 Yomogida, Naruko-onsen, Osaki, Miyagi 989-6711, Japan
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5
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Li J, Fan G, Sakari M, Tsukahara T. Improvement of C-to-U RNA editing using an artificial MS2-APOBEC system. Biotechnol J 2024; 19:e2300321. [PMID: 38010373 DOI: 10.1002/biot.202300321] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 11/29/2023]
Abstract
RNA cytidine deamination (C-to-U editing) has been achieved using the MS2-apolipoprotein B-editing catalytic polypeptide-like (APOBEC)1 editing system. Here, we fused the cytidine deaminase (CDA) enzymes APOBEC3A and APOBEC3G with the MS2 system and examined their RNA editing efficiencies in transfected HEK 293T cells. Given the single-stranded RNA preferences of APOBEC3A and APOBEC3G, we designed unconventional guide RNAs that induced a loop at the target sequence, allowing the target to form a single-stranded structure. Because APOBEC3A and APOBEC3G have different base preferences (5'-TC and 5'-CC, respectively), we introduced the D317W mutation into APOBEC3G to convert its base preference to that of APOBEC3A. Upon co-transfection with a guide RNA that induced the formation of a 14 nt loop on the target sequence, MS2-fused APOBEC3A and APOBEC3G showed high editing efficiency. While the D317W mutation of APOBEC3G led to a slight improvement in editing efficiency, the difference was not statistically significant. These findings indicate that APOBEC3A and APOBEC3G can induce C-to-U RNA editing when transfected with a loop guide RNA. Moreover, the editing efficiency of APOBEC3G can be enhanced by site-specific mutation to alter the base preference. Overall, our results demonstrate that the MS2 system can fuse and catalyze reactions with different enzymes, suggesting that it holds an even greater potential for RNA editing than is utilized currently.
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Affiliation(s)
- Jiarui Li
- Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, Japan
| | - Guangyao Fan
- Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, Japan
- School of Medicine, Shaoxing University, Shaoxing, China
| | - Matomo Sakari
- Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, Japan
| | - Toshifumi Tsukahara
- Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology, Nomi, Ishikawa, Japan
- GeCoRT Co. Ltd., Nishi-ku, Yokohama, Japan
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Azad MTA, Qulsum U, Tsukahara T. Examination of Factors Affecting Site-Directed RNA Editing by the MS2-ADAR1 Deaminase System. Genes (Basel) 2023; 14:1584. [PMID: 37628635 PMCID: PMC10454654 DOI: 10.3390/genes14081584] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 08/02/2023] [Accepted: 08/03/2023] [Indexed: 08/27/2023] Open
Abstract
Adenosine deaminases acting on RNA (ADARs) have double-stranded RNA binding domains and a deaminase domain (DD). We used the MS2 system and specific guide RNAs to direct ADAR1-DD to target adenosines in the mRNA encoding-enhanced green fluorescence protein. Using this system in transfected HEK-293 cells, we evaluated the effects of changing the length and position of the guide RNA on the efficiency of conversion of amber (TAG) and ochre (TAA) stop codons to tryptophan (TGG) in the target. Guide RNAs of 19, 21 and 23 nt were positioned upstream and downstream of the MS2-RNA, providing a total of six guide RNAs. The upstream guide RNAs were more functionally effective than the downstream guide RNAs, with the following hierarchy of efficiency: 21 nt > 23 nt > 19 nt. The highest editing efficiency was 16.6%. Off-target editing was not detected in the guide RNA complementary region but was detected 50 nt downstream of the target. The editing efficiency was proportional to the amount of transfected deaminase but inversely proportional to the amount of the transfected guide RNA. Our results suggest that specific RNA editing requires precise optimization of the ratio of enzyme, guide RNA, and target RNA.
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Affiliation(s)
- Md Thoufic Anam Azad
- Area of Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi City 923-1292, Ishikawa, Japan; (M.T.A.A.)
- Department of Veterinary and Animal Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Umme Qulsum
- Area of Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi City 923-1292, Ishikawa, Japan; (M.T.A.A.)
- Department of Botany, Faculty of Biological Sciences, University of Rajshahi, Rajshahi 6205, Bangladesh
| | - Toshifumi Tsukahara
- Area of Bioscience, Biotechnology and Biomedical Engineering Research Area, Japan Advanced Institute of Science and Technology (JAIST), 1-1 Asahidai, Nomi City 923-1292, Ishikawa, Japan; (M.T.A.A.)
- GeCoRT Co., Ltd., 2-11-2 Takashima, Nishi-ku, Yokohama 220-0011, Kanagawa, Japan
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7
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Ai X, Zhou S, Chen M, Du F, Yuan Y, Cui X, Dong J, Huang X, Tang Z. Leveraging Small Molecule-Induced Aptazyme Cleavage for Directed A-to-I RNA Editing. ACS Synth Biol 2023. [PMID: 37384927 DOI: 10.1021/acssynbio.3c00038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/01/2023]
Abstract
As a promising therapeutic approach for the correction of pathogenic mutations, the RNA editing process is reversible and tunable without permanently altering the genome. RNA editing mediated by human ADAR proteins offers distinct advantages, including high specificity and low propensity to cause immunogenicity. Herein, we describe a small molecule-inducible RNA editing strategy by incorporating aptazymes into the guide RNA of ADAR-based RNA editing technology. Once small molecules are added or removed, aptazymes trigger self-cleavage to release the guide RNA, achieving small molecule-controlled RNA editing. To satisfy different RNA editing applications, both turn-on and turn-off A-to-I RNA editing of target mRNA have been realized by using on/off-switch aptazymes. Theoretically speaking, this strategy can be applied to various ADAR-based editing systems, which could improve the safety and potential clinical applications of RNA editing technology.
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Affiliation(s)
- Xilei Ai
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Shan Zhou
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Meiyi Chen
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P.R. China
| | - Feng Du
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
| | - Yi Yuan
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
| | - Xin Cui
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
| | - Juan Dong
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
| | - Xin Huang
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
| | - Zhuo Tang
- Natural Products Research Center, Chengdu Institute of Biology, Chinese Academy of Science, Chengdu 610041, P. R. China
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8
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Abstract
Cardiovascular disease still remains the leading cause of morbidity and mortality worldwide. Current pharmacological or interventional treatments help to tackle symptoms and even reduce mortality, but cardiovascular disease cases continue to rise. The emergence of novel therapeutic strategies that precisely and efficiently combat cardiovascular disease is therefore deemed more essential than ever. RNA editing, the cell-intrinsic deamination of adenosine or cytidine RNA residues, changes the molecular identity of edited nucleotides, severely altering the fate of RNA molecules involved in key biological processes. The most common type of RNA editing is the deamination of adenosine residue to inosine (A-to-I), which is catalysed by adenosine deaminases acting on RNA (ADARs). Recent efforts have convincingly liaised RNA editing-based mechanisms to the pathophysiology of the cardiovascular system. In this review, we will briefly introduce the basic concepts of the RNA editing field of research. We will particularly focus our discussion on the therapeutic exploitation of RNA editing as a novel therapeutic tool as well as the future perspectives for its use in cardiovascular disease treatment.
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9
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Diaz Quiroz JF, Siskel LD, Rosenthal JJC. Site-directed A → I RNA editing as a therapeutic tool: moving beyond genetic mutations. RNA (NEW YORK, N.Y.) 2023; 29:498-505. [PMID: 36669890 PMCID: PMC10019371 DOI: 10.1261/rna.079518.122] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Adenosine deamination by the ADAR family of enzymes is a natural process that edits genetic information as it passes through messenger RNA. Adenosine is converted to inosine in mRNAs, and this base is interpreted as guanosine during translation. Realizing the potential of this activity for therapeutics, a number of researchers have developed systems that redirect ADAR activity to new targets, ones that are not normally edited. These site-directed RNA editing (SDRE) systems can be broadly classified into two categories: ones that deliver an antisense RNA oligonucleotide to bind opposite a target adenosine, creating an editable structure that endogenously expressed ADARs recognize, and ones that tether the catalytic domain of recombinant ADAR to an antisense RNA oligonucleotide that serves as a targeting mechanism, much like with CRISPR-Cas or RNAi. To date, SDRE has been used mostly to try and correct genetic mutations. Here we argue that these applications are not ideal SDRE, mostly because RNA edits are transient and genetic mutations are not. Instead, we suggest that SDRE could be used to tune cell physiology to achieve temporary outcomes that are therapeutically advantageous, particularly in the nervous system. These include manipulating excitability in nociceptive neural circuits, abolishing specific phosphorylation events to reduce protein aggregation related to neurodegeneration or reduce the glial scarring that inhibits nerve regeneration, or enhancing G protein-coupled receptor signaling to increase nerve proliferation for the treatment of sensory disorders like blindness and deafness.
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Affiliation(s)
- Juan F Diaz Quiroz
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
| | - Louise D Siskel
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
| | - Joshua J C Rosenthal
- Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, Massachusetts 02543, USA
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10
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Lei Z, Meng H, Zhuang Y, Zhu Q, Yi C. Chemical and Biological Approaches to Interrogate off-Target Effects of Genome Editing Tools. ACS Chem Biol 2023; 18:205-217. [PMID: 36731114 DOI: 10.1021/acschembio.2c00836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Various genome editing tools have been developed for programmable genome manipulation at specified genomic loci. However, it is crucial to comprehensively interrogate the off-target effect induced by these genome editing tools, especially when apply them onto the therapeutic applications. Here, we outlined the off-target effect that has been observed for various genome editing tools. We also reviewed detection methods to determine or evaluate the off-target editing, and we have discussed their advantages and limitations. Additionally, we have summarized current RNA editing tools for RNA therapy and medicine that may serve as alternative approaches for genome editing tools in both research and clinical applications.
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Affiliation(s)
- Zhixin Lei
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing100871, China
| | - Haowei Meng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing100871, China
| | - Yuan Zhuang
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Peking University, Beijing100871, China
| | - Qingguo Zhu
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing100871, China.,Academy for Advanced Interdisciplinary Studies, Peking University, Beijing100871, China
| | - Chengqi Yi
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing100871, China.,State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing100871, China.,Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing100871, China.,Peking University Genome Editing Research Center, Peking University, Beijing100871, China
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11
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Li M, Yan C, Jiao Y, Xu Y, Bai C, Miao R, Jiang J, Liu J. Site-directed RNA editing by harnessing ADARs: advances and challenges. Funct Integr Genomics 2022; 22:1089-1103. [DOI: 10.1007/s10142-022-00910-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 11/04/2022]
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12
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Xiao Q, Xu Z, Xue Y, Xu C, Han L, Liu Y, Wang F, Zhang R, Han S, Wang X, Li GL, Li H, Yang H, Shu Y. Rescue of autosomal dominant hearing loss by in vivo delivery of mini dCas13X-derived RNA base editor. Sci Transl Med 2022; 14:eabn0449. [PMID: 35857824 DOI: 10.1126/scitranslmed.abn0449] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Programmable RNA editing tools enable the reversible correction of mutant transcripts, reducing the potential risk associated with permanent genetic changes associated with the use of DNA editing tools. However, the potential of these RNA tools to treat disease remains unknown. Here, we evaluated RNA correction therapy with Cas13-based RNA base editors in the myosin VI p.C442Y heterozygous mutation (Myo6C442Y/+) mouse model that recapitulated the phenotypes of human dominant-inherited deafness. We first screened several variants of Cas13-based RNA base editors and guide RNAs (gRNAs) targeting Myo6C442Y in cultured cells and found that mini dCas13X.1-based adenosine base editor (mxABE), composed of truncated Cas13X.1 and the RNA editing enzyme adenosine deaminase acting on RNA 2 deaminase domain variant (ADAR2ddE488Q), exhibited both high efficiency of A > G conversion and low frequency of off-target edits. Single adeno-associated virus (AAV)-mediated delivery of mxABE in the cochlea corrected the mutated Myo6C442Y to Myo6WT allele in homozygous Myo6C442Y/C442Y mice and resulted in increased Myo6WT allele in the injected cochlea of Myo6C442Y/+ mice. The treatment rescued auditory function, including auditory brainstem response and distortion product otoacoustic emission up to 3 months after AAV-mxABE-Myo6 injection in Myo6C442Y/+ mice. We also observed increased survival rate of hair cells and decreased degeneration of hair bundle morphology in the treated compared to untreated control ears. These findings provide a proof-of-concept study for RNA editing tools as a therapeutic treatment for various semidominant forms of hearing loss and other diseases.
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Affiliation(s)
- Qingquan Xiao
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Zhijiao Xu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
| | - Yuanyuan Xue
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
| | - Chunlong Xu
- Lingang Laboratory, Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai 200032, China
| | - Lei Han
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
- Department of Otorhinolaryngology, Second Affiliated Hospital, University of South China, Hengyang 421001, China
| | - Yuanhua Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Fang Wang
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
| | - Runze Zhang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shuang Han
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
- Department of Otolaryngology Head and Neck Surgery, Second Hospital of Jilin University, Changchun 130000, China
| | - Xing Wang
- Huigene Therapeutics Inc., Shanghai 201315, China
| | - Geng-Lin Li
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
| | - Huawei Li
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
- Institutes of Brain Science and the Collaborative Innovation Center for Brain Science, Fudan University, Shanghai 200032, China
| | - Hui Yang
- Institute of Neuroscience, State Key Laboratory of Neuroscience, Key Laboratory of Primate Neurobiology, CAS Center for Excellence in Brain Science and Intelligence Technology, Shanghai Research Center for Brain Science and Brain-Inspired Intelligence, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yilai Shu
- ENT Institute and Department of Otorhinolaryngology, Eye & ENT Hospital, State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Fudan University, Shanghai 200031, China
- Institutes of Biomedical Sciences, Fudan University, Shanghai 200032, China
- NHC Key Laboratory of Hearing Medicine, Fudan University, Shanghai 200032, China
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13
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Saifullah, Motohashi N, Tsukahara T, Aoki Y. Development of Therapeutic RNA Manipulation for Muscular Dystrophy. Front Genome Ed 2022; 4:863651. [PMID: 35620642 PMCID: PMC9127466 DOI: 10.3389/fgeed.2022.863651] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 04/12/2022] [Indexed: 11/16/2022] Open
Abstract
Approval of therapeutic RNA molecules, including RNA vaccines, has paved the way for next-generation treatment strategies for various diseases. Oligonucleotide-based therapeutics hold particular promise for treating incurable muscular dystrophies, including Duchenne muscular dystrophy (DMD). DMD is a severe monogenic disease triggered by deletions, duplications, or point mutations in the DMD gene, which encodes a membrane-linked cytoskeletal protein to protect muscle fibers from contraction-induced injury. Patients with DMD inevitably succumb to muscle degeneration and atrophy early in life, leading to premature death from cardiac and respiratory failure. Thus far, the disease has thwarted all curative strategies. Transcriptomic manipulation, employing exon skipping using antisense oligonucleotides (ASO), has made significant progress in the search for DMD therapeutics. Several exon-skipping drugs employing RNA manipulation technology have been approved by regulatory agencies and have shown promise in clinical trials. This review summarizes recent scientific and clinical progress of ASO and other novel RNA manipulations, including RNA-based editing using MS2 coat protein-conjugated adenosine deaminase acting on the RNA (MCP-ADAR) system illustrating the efficacy and limitations of therapies to restore dystrophin. Perhaps lessons from this review will encourage the application of RNA-editing therapy to other neuromuscular disorders.
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Affiliation(s)
- Saifullah
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Norio Motohashi
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
| | - Toshifumi Tsukahara
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology (JAIST), Ishikawa, Japan
- Division of Transdisciplinary Science, Japan Advanced Institute of Science and Technology (JAIST), Ishikawa, Japan
| | - Yoshitsugu Aoki
- Department of Molecular Therapy, National Institute of Neuroscience, National Center of Neurology and Psychiatry (NCNP), Tokyo, Japan
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14
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Xu W, Biswas J, Singer RH, Rosbash M. Targeted RNA editing: novel tools to study post-transcriptional regulation. Mol Cell 2022; 82:389-403. [PMID: 34739873 PMCID: PMC8792254 DOI: 10.1016/j.molcel.2021.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/06/2021] [Accepted: 10/11/2021] [Indexed: 01/22/2023]
Abstract
RNA binding proteins (RBPs) regulate nearly all post-transcriptional processes within cells. To fully understand RBP function, it is essential to identify their in vivo targets. Standard techniques for profiling RBP targets, such as crosslinking immunoprecipitation (CLIP) and its variants, are limited or suboptimal in some situations, e.g. when compatible antibodies are not available and when dealing with small cell populations such as neuronal subtypes and primary stem cells. This review summarizes and compares several genetic approaches recently designed to identify RBP targets in such circumstances. TRIBE (targets of RNA binding proteins identified by editing), RNA tagging, and STAMP (surveying targets by APOBEC-mediated profiling) are new genetic tools useful for the study of post-transcriptional regulation and RBP identification. We describe the underlying RNA base editing technology, recent applications, and therapeutic implications.
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Affiliation(s)
- Weijin Xu
- Howard Hughes Medical Institute, Department of Biology, Brandeis University, Waltham, MA 02451, USA
| | - Jeetayu Biswas
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Michael Rosbash
- Howard Hughes Medical Institute, Department of Biology, Brandeis University, Waltham, MA 02451, USA.
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15
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Khosravi HM, Jantsch MF. Site-directed RNA editing: recent advances and open challenges. RNA Biol 2021; 18:41-50. [PMID: 34569891 PMCID: PMC8677011 DOI: 10.1080/15476286.2021.1983288] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2021] [Revised: 08/25/2021] [Accepted: 09/16/2021] [Indexed: 12/19/2022] Open
Abstract
RNA editing by cytosine and adenosine deaminases changes the identity of the edited bases. While cytosines are converted to uracils, adenines are converted to inosines. If coding regions of mRNAs are affected, the coding potential of the RNA can be changed, depending on the codon affected. The recoding potential of nucleotide deaminases has recently gained attention for their ability to correct genetic mutations by either reverting the mutation itself or by manipulating processing steps such as RNA splicing. In contrast to CRISPR-based DNA-editing approaches, RNA editing events are transient in nature, therefore reducing the risk of long-lasting inadvertent side-effects. Moreover, some RNA-based therapeutics are already FDA approved and their use in targeting multiple cells or organs to restore genetic function has already been shown. In this review, we provide an overview on the current status and technical differences of site-directed RNA-editing approaches. We also discuss advantages and challenges of individual approaches.
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Affiliation(s)
- Hamid Mansouri Khosravi
- Center of Anatomy & Cell Biology Division of Cell & Developmental Biology Medical, Unviersity of Vienna SchwarzspanierstrasseVienna, Austria
| | - Michael F. Jantsch
- Center of Anatomy & Cell Biology Division of Cell & Developmental Biology Medical, Unviersity of Vienna SchwarzspanierstrasseVienna, Austria
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16
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Ojha N, Diaz Quiroz JF, Rosenthal JJC. In vitro and in cellula site-directed RNA editing using the λNDD-BoxB system. Methods Enzymol 2021; 658:335-358. [PMID: 34517953 DOI: 10.1016/bs.mie.2021.06.009] [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: 01/04/2023]
Abstract
Site-directed RNA editing (SDRE) exploits the enzymatic activity of Adenosine Deaminases Acting on RNAs (ADAR) to program changes in genetic information as it passes through RNA. ADARs convert adenosine (A) to inosine (I) through a hydrolytic deamination and since I can be read as guanosine (G) during translation, this change can regulate gene function and correct G→A genetic mutations. In SDRE, ADARs are redirected to convert user-defined A's to I's. SDRE also has certain advantages over genome editing because the changes in RNA are reversible and thus safer. In addition, ADARs are endogenously expressed in humans and therefore unlikely to provoke immunological complications when administered. Recently, a variety of systems for SDRE have been developed. Some rely on harnessing endogenously expressed ADARs and other deliver engineered versions of ADAR's catalytic domain. All systems are currently under refinement, and there are still challenges associated with raising their efficiency and specificity to levels that are adequate for therapeutics. This chapter provides a detailed protocol for in vitro and in cellula editing assays using the λNDD-BoxB system, one of the first systems developed for SDRE. The λNDD-BoxB system relies on gRNAs that are linked to the catalytic domain of human ADAR2 through a small RNA binding protein-RNA stem/loop interaction. We provide step-by-step protocols for (a) the construction of guide RNAs and editing enzyme plasmids, and (b) their use in vitro and in cellula for editing assays using a fluorescent protein-based reporter system containing a premature termination codon that can be corrected by editing.
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Affiliation(s)
- Namrata Ojha
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, United States
| | | | - Joshua J C Rosenthal
- The Eugene Bell Center, The Marine Biological Laboratory, Woods Hole, MA, United States.
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17
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Bhakta S, Tsukahara T. Artificial RNA Editing with ADAR for Gene Therapy. Curr Gene Ther 2021; 20:44-54. [PMID: 32416688 DOI: 10.2174/1566523220666200516170137] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/28/2020] [Accepted: 04/29/2020] [Indexed: 12/14/2022]
Abstract
Editing mutated genes is a potential way for the treatment of genetic diseases. G-to-A mutations are common in mammals and can be treated by adenosine-to-inosine (A-to-I) editing, a type of substitutional RNA editing. The molecular mechanism of A-to-I editing involves the hydrolytic deamination of adenosine to an inosine base; this reaction is mediated by RNA-specific deaminases, adenosine deaminases acting on RNA (ADARs), family protein. Here, we review recent findings regarding the application of ADARs to restoring the genetic code along with different approaches involved in the process of artificial RNA editing by ADAR. We have also addressed comparative studies of various isoforms of ADARs. Therefore, we will try to provide a detailed overview of the artificial RNA editing and the role of ADAR with a focus on the enzymatic site directed A-to-I editing.
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Affiliation(s)
- Sonali Bhakta
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, 923-1292, Japan
| | - Toshifumi Tsukahara
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, 923-1292, Japan
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18
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Bhakta S, Tsukahara T. Double MS2 guided restoration of genetic code in amber (TAG), opal (TGA) and ochre (TAA) stop codon. Enzyme Microb Technol 2021; 149:109851. [PMID: 34311888 DOI: 10.1016/j.enzmictec.2021.109851] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 11/26/2022]
Abstract
The popularity and promise of gene therapy for common genetic diseases are currently increasing. Although effective treatments for genetic disorders are rare, editing of the mutated gene is a possible therapeutic approach for conditions caused by stop codon mutations, including either amber (TAG), opal (TGA) or ochre (TAA) stop codons. Restoration of point-mutated RNAs using artificial RNA editing can be used to modify gene-encoded information and generate functionally distinct proteins from a single gene. By linking the catalytic domain of the RNA editing enzyme, adenosine deaminase acting on RNA (ADAR), to an antisense guide RNA, specific adenosines (A) can be converted to inosine (I), which is recognized as guanosine (G) during translation. In this study, we engineered the deaminase domain of ADAR1 and the MS2 system to target a specific adenosine and restore the G to A mutations. To this end, the ADAR1 deaminase domain was fused with the RNA binding protein, MS2, which binds to MS2 RNA. Guide RNAs of 19 bp were designed to be complementary to target mRNAs, with either 6X stem-loops downstream of the guide RNA and a CMV promoter, or a 1X MS2 stem-loop on either side of the guide RNA and a U6 promoter. The engineered ADAR1 deaminase domain could convert adenosine to inosine at the desired editing site in EGFP, which was edited to contain an amber (TAG), opal (TGA) or ochre (TAA) stop codon. The system could convert the stop codons to a read-through tryptophan codon (TGG) in a cellular system, leading to fluorescence emission, observed using JuLi microscopy. PCR-RFLP and Sanger sequencing of the target transcript were also conducted, revealing an editing efficiency of 20.97 % for the opal stop codon, and 26 % and 17 % for the 5' and 3' A residues, respectively, in the ochre stop codon, using the double MS2. This was a higher editing rate than that achieved using the MS2-6X guide RNA. Observation of restoration of the read-through codon from the three different stop codons over time demonstrated a relatively low percentage of edited codons after 24 h, which increased after 48 h, but decreased again after 72 h. Successful establishment of this system has the potential to represent a new era in the field of gene therapy.
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Affiliation(s)
- Sonali Bhakta
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, 923-1292, Japan; Department of Anatomy and Histology, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh.
| | - Toshifumi Tsukahara
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, 923-1292, Japan.
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19
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Doherty EE, Wilcox XE, van Sint Fiet L, Kemmel C, Turunen JJ, Klein B, Tantillo DJ, Fisher AJ, Beal PA. Rational Design of RNA Editing Guide Strands: Cytidine Analogs at the Orphan Position. J Am Chem Soc 2021; 143:6865-6876. [PMID: 33939417 PMCID: PMC8608393 DOI: 10.1021/jacs.0c13319] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Adenosine Deaminases Acting on RNA (ADARs) convert adenosine to inosine in double stranded RNA. Human ADARs can be directed to predetermined target sites in the transcriptome by complementary guide strands, allowing for the correction of disease-causing mutations at the RNA level. Here we use structural information available for ADAR2-RNA complexes to guide the design of nucleoside analogs for the position in the guide strand that contacts a conserved glutamic acid residue in ADARs (E488 in human ADAR2), which flips the adenosine into the ADAR active site for deamination. Mutating this residue to glutamine (E488Q) results in higher activity because of the hydrogen bond donating ability of Q488 to N3 of the orphan cytidine on the guide strand. We describe the evaluation of cytidine analogs for this position that stabilize an activated conformation of the enzyme-RNA complex and increase catalytic rate for deamination by the wild-type enzyme. A new crystal structure of ADAR2 bound to duplex RNA bearing a cytidine analog revealed a close contact between E488, stabilized by an additional hydrogen bond and altered charge distribution when compared to cytidine. In human cells and mouse primary liver fibroblasts, this single nucleotide modification increased directed editing yields when compared to an otherwise identical guide oligonucleotide. Our results show that modification of the guide RNA can mimic the effect of hyperactive mutants and advance the approach of recruiting endogenous ADARs for site-directed RNA editing.
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Affiliation(s)
- Erin E Doherty
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Xander E Wilcox
- Department of Chemistry, University of California, Davis, California 95616, United States
| | | | | | | | - Bart Klein
- ProQR Therapeutics, 2333 CK Leiden, The Netherlands
| | - Dean J Tantillo
- Department of Chemistry, University of California, Davis, California 95616, United States
| | - Andrew J Fisher
- Department of Chemistry, University of California, Davis, California 95616, United States
- Department of Molecular and Cellular Biology, University of California, Davis, California 95616, United States
| | - Peter A Beal
- Department of Chemistry, University of California, Davis, California 95616, United States
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20
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Nose K, Hidaka K, Yano T, Tomita Y, Fukuda M. Short-Chain Guide RNA for Site-Directed A-to-I RNA Editing. Nucleic Acid Ther 2021; 31:58-67. [PMID: 33170095 DOI: 10.1089/nat.2020.0866] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Site-directed RNA editing is a promising genetic modification technology for therapeutic and pharmaceutical applications. We previously constructed adenosine deaminases acting on RNA (ADAR)-guiding RNAs (AD-gRNAs) that direct A-to-I RNA editing activity of native human ADAR2 into a programmable target site. In this study, we developed the short-chain AD-gRNA (shAD-gRNA) as a potential basic framework for practical RNA-editing oligonucleotides. Based on knowledge of previous AD-gRNA, shAD-gRNAs were designed to have the shortest possible sequence for the induction of editing activity. In vitro, compared to the original AD-gRNA, the shAD-gRNAs showed similar or superior editing induction activity, depending on the target RNA sequence, and had lower off-target editing activity around the target site, which is predicted to be a hotspot for off-target editing. Moreover, shAD-gRNAs achieved target RNA editing with both exogenous and endogenous human ADARs in cultured cells. Our results present shAD-gRNA as a short basic framework that would be applicable to further development for practical RNA-editing oligonucleotides.
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Affiliation(s)
- Kanako Nose
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Kota Hidaka
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Takashi Yano
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Yohei Tomita
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
| | - Masatora Fukuda
- Department of Chemistry, Faculty of Science, Fukuoka University, Fukuoka, Japan
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21
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Marina RJ, Brannan KW, Dong KD, Yee BA, Yeo GW. Evaluation of Engineered CRISPR-Cas-Mediated Systems for Site-Specific RNA Editing. Cell Rep 2020; 33:108350. [PMID: 33147453 PMCID: PMC8985550 DOI: 10.1016/j.celrep.2020.108350] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 09/30/2020] [Accepted: 10/13/2020] [Indexed: 12/17/2022] Open
Abstract
Site-directed RNA editing approaches offer great potential to correct genetic mutations in somatic cells while avoiding permanent off-target genomic edits. Nuclease-dead RNA-targeting CRISPR-Cas systems recruit functional effectors to RNA molecules in a programmable fashion. Here, we demonstrate a Streptococcus pyogenes Cas9-ADAR2 fusion system that uses a 3' modified guide RNA (gRNA) to enable adenosine-to-inosine (A-to-I) editing of specific bases on reporter and endogenously expressed mRNAs. Due to the sufficient nature of the 3' gRNA extension sequence, we observe that Cas9 gRNA spacer sequences are dispensable for directed RNA editing, revealing that Cas9 can act as an RNA-aptamer-binding protein. We demonstrate that Cas9-based A-to-I editing is comparable in on-target efficiency and off-target specificity with Cas13 RNA editing versions. This study provides a systematic benchmarking of RNA-targeting CRISPR-Cas designs for reversible nucleotide-level conversion at the transcriptome level.
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Affiliation(s)
- Ryan J Marina
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Kristopher W Brannan
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Kevin D Dong
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Brian A Yee
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA; Stem Cell Program, University of California San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA 92093, USA.
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22
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Liu Y, Mao S, Huang S, Li Y, Chen Y, Di M, Huang X, Lv J, Wang X, Ge J, Shen S, Zhang X, Liu D, Huang X, Chi T. REPAIRx, a specific yet highly efficient programmable A > I RNA base editor. EMBO J 2020; 39:e104748. [PMID: 33058207 DOI: 10.15252/embj.2020104748] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 05/27/2020] [Accepted: 06/03/2020] [Indexed: 12/26/2022] Open
Abstract
Programmable A > I RNA editing is a valuable tool for basic research and medicine. A variety of editors have been created, but a genetically encoded editor that is both precise and efficient has not been described to date. The trade-off between precision and efficiency is exemplified in the state of the art editor REPAIR, which comprises the ADAR2 deaminase domain fused to dCas13b. REPAIR is highly efficient, but also causes significant off-target effects. Mutations that weaken the deaminase domain can minimize the undesirable effects, but this comes at the expense of on-target editing efficiency. We have now overcome this dilemma by using a multipronged approach: We have chosen an alternative Cas protein (CasRx), inserted the deaminase domain into the middle of CasRx, and redirected the editor to the nucleus. The new editor created, dubbed REPAIRx, is precise yet highly efficient, outperforming various previous versions on both mRNA and nuclear RNA targets. Thus, REPAIRx markedly expands the RNA editing toolkit and illustrates a novel strategy for base editor optimization.
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Affiliation(s)
- Yajing Liu
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Shaoshuai Mao
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Shisheng Huang
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Yongqin Li
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China.,Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Yuxin Chen
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Minghui Di
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xinxin Huang
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Junjun Lv
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xinxin Wang
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China
| | - Jianyang Ge
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China
| | - Shengxi Shen
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoming Zhang
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,University of Chinese Academy of Sciences, Beijing, China
| | - Dahai Liu
- Department of Basic Medicine and Biomedical Engineering, School of Stomatology and Medicine, Foshan University, Foshan, China
| | - Xingxu Huang
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China
| | - Tian Chi
- School of Life Sciences and Technology, ShanghaiTech University, Shanghai, China.,Department of Immunobiology, Yale University School of Medicine, New Haven, CT, USA
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23
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RNA editing of BFP, a point mutant of GFP, using artificial APOBEC1 deaminase to restore the genetic code. Sci Rep 2020; 10:17304. [PMID: 33057101 PMCID: PMC7560856 DOI: 10.1038/s41598-020-74374-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Accepted: 09/24/2020] [Indexed: 02/07/2023] Open
Abstract
Many genetic diseases are caused by T-to-C point mutations. Hence, editing of mutated genes represents a promising strategy for treating these disorders. We engineered an artificial RNA editase by combining the deaminase domain of APOBEC1 (apolipoprotein B mRNA editing catalytic polypeptide 1) with a guideRNA (gRNA) which is complementary to target mRNA. In this artificial enzyme system, gRNA is bound to MS2 stem-loop, and deaminase domain, which has the ability to convert mutated target nucleotide C-to-U, is fused to MS2 coat protein. As a target RNA, we used RNA encoding blue fluorescent protein (BFP) which was derived from the gene encoding GFP by 199 T > C mutation. Upon transient expression of both components (deaminase and gRNA), we observed GFP by confocal microscopy, indicating that mutated 199C in BFP had been converted to U, restoring original sequence of GFP. This result was confirmed by PCR–RFLP and Sanger’s sequencing using cDNA from transfected cells, revealing an editing efficiency of approximately 21%. Although deep RNA sequencing result showed some off-target editing events in this system, we successfully developed an artificial RNA editing system using artificial deaminase (APOBEC1) in combination with MS2 system could lead to therapies that treat genetic disease by restoring wild-type sequence at the mRNA level.
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24
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Tohama T, Sakari M, Tsukahara T. Development of a Single Construct System for Site-Directed RNA Editing Using MS2-ADAR. Int J Mol Sci 2020; 21:E4943. [PMID: 32668759 PMCID: PMC7404196 DOI: 10.3390/ijms21144943] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/08/2020] [Accepted: 07/08/2020] [Indexed: 12/26/2022] Open
Abstract
Site-directed RNA editing (SDRE) technologies have great potential for treating genetic diseases caused by point mutations. Our group and other researchers have developed SDRE methods utilizing adenosine deaminases acting on RNA (ADARs) and guide RNAs recruiting ADARs to target RNAs bearing point mutations. In general, efficient SDRE relies on introducing numerous guide RNAs relative to target genes. However, achieving a large ratio is not possible for gene therapy applications. In order to achieve a realistic ratio, we herein developed a system that can introduce an equal number of genes and guide RNAs into cultured cells using a fusion protein comprising an ADAR fragment and a plasmid vector containing one copy of each gene on a single construct. We transfected the single construct into HEK293T cells and achieved relatively high efficiency (up to 42%). The results demonstrate that efficient SDRE is possible when the copy number is similar for all three factors (target gene, guide RNA, and ADAR enzyme). This method is expected to be capable of highly efficient gene repair in vivo, making it applicable for gene therapy.
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Affiliation(s)
| | | | - Toshifumi Tsukahara
- Area of Bioscience and Biotechnology, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan; (T.T.); (M.S.)
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Novel Engineered Programmable Systems for ADAR-Mediated RNA Editing. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 19:1065-1072. [PMID: 32044725 PMCID: PMC7015837 DOI: 10.1016/j.omtn.2019.12.042] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/24/2019] [Accepted: 12/24/2019] [Indexed: 12/26/2022]
Abstract
One of the most prevalent forms of post-transcriptional RNA modification is the conversion of adenosine-to-inosine (A-to-I), mediated by adenosine deaminase acting on RNA (ADAR) enzymes. The advent of the CRISPR/Cas systems inspires researchers to work actively in the engineering of programmable RNA-guided machines for basic research and biomedical applications. In this regard, CIRTS (CRISPR-Cas-Inspired RNA Targeting System), RESCUE (RNA Editing for Specific C to U Exchange), RESTORE (Recruiting Endogenous ADAR to Specific Transcripts for Oligonucleotide-mediated RNA Editing), and LEAPER (Leveraging Endogenous ADAR for Programmable Editing of RNA) are innovative RNA base-editing platforms that have recently been engineered to perform programmable base conversions on target RNAs mediated by ADAR enzymes in mammalian cells. Thus, these four currently characterized RNA-editing systems constitute novel molecular tools with compelling programmability, specificity, and efficiency that show us some creative ways to take advantage of the engineered deaminases for precise base editing. Moreover, the advanced engineering of these systems permits editing of full-length transcripts containing disease-causing point mutations without the loss of genomic information, providing an attractive alternative for in vivo research and in the therapeutic setting if the challenges encountered in off-target edits and delivery are appropriately addressed. Here, I present an analytical approach of the current status and rapid progress of the novel ADAR-mediated RNA-editing systems when highlighting the qualities of each new RNA-editing platform and how these RNA-targeting strategies could be used to recruit human ADARs on endogenous transcripts, not only for our understanding of RNA-modification-mediated regulation of gene expression but also for editing clinically relevant mutations in a programmable and straightforward manner.
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Bhakta S, Azad MTA, Tsukahara T. Genetic code restoration by artificial RNA editing of Ochre stop codon with ADAR1 deaminase. Protein Eng Des Sel 2019; 31:471-478. [PMID: 31120126 DOI: 10.1093/protein/gzz005] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 02/21/2019] [Accepted: 03/13/2019] [Indexed: 01/14/2023] Open
Abstract
Site directed mutagenesis is a very effective approach to recode genetic information. Proper linking of the catalytic domain of the RNA editing enzyme adenosine deaminase acting on RNA (ADAR) to an antisense guide RNA can convert specific adenosines (As) to inosines (Is), with the latter recognized as guanosines (Gs) during the translation process. Efforts have been made to engineer the deaminase domain of ADAR1 and the MS2 system to target specific A residues to restore G→A mutations. The target consisted of an ochre (TAA) stop codon, generated from the TGG codon encoding amino acid 58 (Trp) of enhanced green fluorescent protein (EGFP). This system had the ability to convert the stop codon (TAA) to a readable codon (TGG), thereby restoring fluorescence in a cellular system, as shown by JuLi fluorescence and LSM confocal microscopy. The specificity of the editing was confirmed by polymerase chain reaction-restriction fragment length polymorphism, as the restored EGFP mRNA could be cleaved into fragments of 160 and 100 base pairs. Direct sequencing analysis with both sense and antisense primers showed that the restoration rate was higher for the 5' than for the 3'A. This system may be very useful for treating genetic diseases that result from G→A point mutations. Successful artificial editing of RNA in vivo can accelerate research in this field, and pioneer genetic code restoration therapy, including stop codon read-through therapy, for various genetic diseases.
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Affiliation(s)
- Sonali Bhakta
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, Japan
| | - Md Thoufic Anam Azad
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, Japan.,Department of Veterinary and Animal Sciences, Faculty of Agriculture, University of Rajshahi, Rajshahi
| | - Toshifumi Tsukahara
- Area of Bioscience and Biotechnology, School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomicity, Ishikawa, Japan
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Azad MTA, Qulsum U, Tsukahara T. Comparative Activity of Adenosine Deaminase Acting on RNA (ADARs) Isoforms for Correction of Genetic Code in Gene Therapy. Curr Gene Ther 2019; 19:31-39. [DOI: 10.2174/1566523218666181114122116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 11/12/2018] [Accepted: 11/13/2018] [Indexed: 12/26/2022]
Abstract
Introduction:
Members of the adenosine deaminase acting on RNA (ADAR) family of enzymes
consist of double-stranded RNA-binding domains (dsRBDs) and a deaminase domain (DD)
that converts adenosine (A) into inosine (I), which acts as guanosine (G) during translation. Using the
MS2 system, we engineered the DD of ADAR1 to direct it to a specific target. The aim of this work
was to compare the deaminase activities of ADAR1-DD and various isoforms of ADAR2-DD.
Materials and Methods:
We measured the binding affinity of the artificial enzyme system on a Biacore
™ X100. ADARs usually target dsRNA, so we designed a guide RNA complementary to the target
RNA, and then fused the guide sequence to the MS2 stem-loop. A mutated amber (TAG) stop
codon at 58 amino acid (TGG) of EGFP was targeted. After transfection of these three factors into
HEK 293 cells, we observed fluorescence signals of various intensities.
Results:
ADAR2-long without the Alu-cassette yielded a much higher fluorescence signal than
ADAR2-long with the Alu-cassette. With another isoform, ADAR2-short, which is 81 bp shorter at
the C-terminus, the fluorescence signal was undetectable. A single amino acid substitution of
ADAR2-long-DD (E488Q) rendered the enzyme more active than the wild type. The results of fluorescence
microscopy suggested that ADAR1-DD is more active than ADAR2-long-DD. Western blots
and sequencing confirmed that ADAR1-DD was more active than any other DD.
Conclusion:
This study provides information that should facilitate the rational use of ADAR variants
for genetic restoration and treatment of genetic diseases.
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Affiliation(s)
- Md. Thoufic A. Azad
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923- 1292, Japan
| | - Umme Qulsum
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923- 1292, Japan
| | - Toshifumi Tsukahara
- School of Materials Science, Japan Advanced Institute of Science and Technology, 1-1 Asahidai, Nomi, Ishikawa 923- 1292, Japan
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Chen G, Katrekar D, Mali P. RNA-Guided Adenosine Deaminases: Advances and Challenges for Therapeutic RNA Editing. Biochemistry 2019; 58:1947-1957. [PMID: 30943016 DOI: 10.1021/acs.biochem.9b00046] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Targeted transcriptome engineering, in contrast to genome engineering, offers a complementary and potentially tunable and reversible strategy for cellular engineering. In this regard, adenosine to inosine (A-to-I) RNA base editing was recently engineered to make programmable base conversions on target RNAs. Similar to the DNA base editing technology, A-to-I RNA editing may offer an attractive alternative in a therapeutic setting, especially for the correction of point mutations. This Perspective introduces five currently characterized RNA editing systems and serves as a reader's guide for implementing an appropriate RNA editing strategy for applications in research or therapeutics.
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Affiliation(s)
- Genghao Chen
- Department of Bioengineering , University of California, San Diego , La Jolla , California 92093-0412 , United States
| | - Dhruva Katrekar
- Department of Bioengineering , University of California, San Diego , La Jolla , California 92093-0412 , United States
| | - Prashant Mali
- Department of Bioengineering , University of California, San Diego , La Jolla , California 92093-0412 , United States
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29
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Katrekar D, Chen G, Meluzzi D, Ganesh A, Worlikar A, Shih YR, Varghese S, Mali P. In vivo RNA editing of point mutations via RNA-guided adenosine deaminases. Nat Methods 2019; 16:239-242. [PMID: 30737497 PMCID: PMC6395520 DOI: 10.1038/s41592-019-0323-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 12/13/2018] [Indexed: 12/16/2022]
Abstract
We present in vivo sequence-specific RNA base editing via adenosine deaminases acting on RNA (ADAR) enzymes with associated ADAR guide RNAs (adRNAs). To achieve this, we systematically engineered adRNAs to harness ADARs, and comprehensively evaluated the specificity and activity of the toolsets in vitro and in vivo via two mouse models of human disease. We anticipate that this platform will enable tunable and reversible engineering of cellular RNAs for diverse applications.
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Affiliation(s)
- Dhruva Katrekar
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Genghao Chen
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Dario Meluzzi
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Ashwin Ganesh
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Atharv Worlikar
- Department of Bioengineering, University of California, San Diego, CA, USA
| | - Yu-Ru Shih
- Department of Bioengineering, University of California, San Diego, CA, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Shyni Varghese
- Department of Bioengineering, University of California, San Diego, CA, USA
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Prashant Mali
- Department of Bioengineering, University of California, San Diego, CA, USA.
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Montiel-Gonzalez MF, Diaz Quiroz JF, Rosenthal JJC. Current strategies for Site-Directed RNA Editing using ADARs. Methods 2019; 156:16-24. [PMID: 30502398 PMCID: PMC6814296 DOI: 10.1016/j.ymeth.2018.11.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 11/22/2018] [Accepted: 11/27/2018] [Indexed: 12/26/2022] Open
Abstract
Adenosine Deaminases that Act on RNA (ADARs) are a group of enzymes that catalyze the conversion of adenosines (A's) to inosines (I's) in a process known as RNA editing. Though ADARs can act on different types of RNA, editing events in coding regions of mRNA are of particular interest as I's base pair like guanosines (G's). Thus, every A-to-I change catalyzed by ADAR is read as an A-to-G change during translation, potentially altering protein sequence and function. This ability to re-code makes ADAR an attractive therapeutic tool to correct genetic mutations within mRNA. The main challenge in doing so is to re-direct ADAR's catalytic activity towards A's that are not naturally edited, a process termed Site-Directed RNA Editing (SDRE). Recently, a handful of labs have taken up this challenge and two basic strategies have emerged. The first involves redirecting endogenous ADAR to new sites by making editable structures using antisense RNA oligonucleotides. The second also utilizes antisense RNA oligonucleotides, but it uses them as guides to deliver the catalytic domain of engineered ADARs to new sites, much as CRISPR guides deliver Cas nucleases. In fact, despite the intense current focus on CRISPR-Cas9 genome editing, SDRE offers a number of distinct advantages. In the present review we will discuss these strategies in greater detail, focusing on the concepts on which they are based, how they were developed and tested, and their respective advantages and disadvantages. Though the precise and efficient re-direction of ADAR activity still remains a challenge, the systems that are being developed lay the foundation for SDRE as a powerful tool for transient genome editing.
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MESH Headings
- Adenosine/metabolism
- Adenosine Deaminase/genetics
- Adenosine Deaminase/metabolism
- Animals
- CRISPR-Associated Protein 9/genetics
- CRISPR-Associated Protein 9/metabolism
- CRISPR-Cas Systems
- Genome, Human
- Humans
- Inosine/metabolism
- Mutagenesis, Site-Directed/methods
- Oligoribonucleotides, Antisense/genetics
- Oligoribonucleotides, Antisense/metabolism
- Protein Domains
- RNA Editing
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
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S S, Fuke S, Nagasawa H, Tsukahara T. Single nucleotide recognition using a probes-on-carrier DNA chip. Biotechniques 2019; 66:73-78. [PMID: 30744407 DOI: 10.2144/btn-2018-0088] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Following the sequencing of the human genome, SNP analysis of individual patients has become essential for achieving the best drug response and ensuring optimal care. In this study, we developed a cost-effective probes-on-carrier DNA chip for the detection of SNPs. Our chips harbored three different probes against the TP53 gene, and were capable of detecting wild-type TP53 and SNPs such as rs121912651 and rs11540652. Four cell lines were used to validate the specificity of probe hybridization. Strong fluorescence intensity was observed in hybridized spots based on hybridization for perfect base pairing between complementary strands, whereas significantly lower fluorescence (p < 0.05) was observed in nonhybridized spots. These hybridization results indicated that the probes-on-carrier chip is suitable for SNP genotyping.
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Affiliation(s)
- Saifullah S
- Area of Bioscience & Biotechnology, School of Materials Science, Japan Advanced Institute of Science & Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Satoshi Fuke
- Area of Bioscience & Biotechnology, School of Materials Science, Japan Advanced Institute of Science & Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan
| | - Hiroshi Nagasawa
- Kankyou Resilience, 79-7 Tokiwadai, Hodogaya, Yokohama, 240-0067, Japan
| | - Toshifumi Tsukahara
- Area of Bioscience & Biotechnology, School of Materials Science, Japan Advanced Institute of Science & Technology (JAIST), 1-1 Asahidai, Nomi, Ishikawa 923-1292, Japan.,Division of Transdisciplinary Science, Japan Advanced Institute of Science & Technology, 1-1 Asahidai, Nomi city, Ishikawa 923-1292, Japan
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