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Xu C, Zhang Y, Ma L, Zhang G, Li C, Zhang C, Li Y, Zeng X, Li Y, Dong N. Valnemulin restores colistin sensitivity against multidrug-resistant gram-negative pathogens. Commun Biol 2024; 7:1122. [PMID: 39261709 PMCID: PMC11390741 DOI: 10.1038/s42003-024-06805-2] [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: 02/22/2024] [Accepted: 08/29/2024] [Indexed: 09/13/2024] Open
Abstract
Colistin is one of the last-resort antibiotics in treating infections caused by multidrug-resistant (MDR) pathogens. Unfortunately, the emergence of colistin-resistant gram-negative strains limit its clinical application. Here, we identify an FDA-approved drug, valnemulin (Val), exhibit a synergistic effect with colistin in eradicating both colistin-resistant and colistin-susceptible gram-negative pathogens both in vitro and in the mouse infection model. Furthermore, Val acts synergistically with colistin in eliminating intracellular bacteria in vitro. Functional studies and transcriptional analysis confirm that the combinational use of Val and colistin could cause membrane permeabilization, proton motive force dissipation, reduction in intracellular ATP level, and suppression in bacterial motility, which result in bacterial membrane disruption and finally cell death. Our findings reveal the potential of Val as a colistin adjuvant to combat MDR bacterial pathogens and treat recalcitrant infections.
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Affiliation(s)
- Chen Xu
- Department of Laboratory Medicine, School of Medicine, Jiangsu University, Zhenjiang, China
| | - Yuan Zhang
- Institute for Brain Science and Disease, Chongqing Medical University, Chongqing, China
| | - Lingman Ma
- School of Life Science and Technology, China Pharmaceutical University, Nanjing, Jiangsu, China
| | - Guangfen Zhang
- MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Department of Medical Microbiology, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, China
| | - Chunli Li
- MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Department of Medical Microbiology, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, China
| | - Chenjie Zhang
- College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou, China
| | - Yunbing Li
- Department of Medical Microbiology, Experimental Center, Suzhou Medical College of Soochow Univesity, Suzhou, China
| | - Xiangkun Zeng
- MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Department of Medical Microbiology, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, China
| | - Yuanyuan Li
- Department of Medical Microbiology, Experimental Center, Suzhou Medical College of Soochow Univesity, Suzhou, China.
| | - Ning Dong
- MOE Key Laboratory of Geriatric Diseases and Immunology, Suzhou Key Laboratory of Pathogen Bioscience and Anti-infective Medicine, Department of Medical Microbiology, School of Basic Medical Sciences, Suzhou Medical College of Soochow University, Suzhou, China.
- Department of Clinical Laboratory, Second Affiliated Hospital, Department of Epidemiology and Biostatistics, School of Public Health, The Key Laboratory of Intelligent Preventive Medicine of Zhejiang Province, Zhejiang University School of Medicine, Hangzhou, China.
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2
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Kato-Inui T, Takahashi G, Ono T, Miyaoka Y. Fusion of histone variants to Cas9 suppresses non-homologous end joining. PLoS One 2024; 19:e0288578. [PMID: 38739603 PMCID: PMC11090291 DOI: 10.1371/journal.pone.0288578] [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: 06/29/2023] [Accepted: 01/11/2024] [Indexed: 05/16/2024] Open
Abstract
As a versatile genome editing tool, the CRISPR-Cas9 system induces DNA double-strand breaks at targeted sites to activate mainly two DNA repair pathways: HDR which allows precise editing via recombination with a homologous template DNA, and NHEJ which connects two ends of the broken DNA, which is often accompanied by random insertions and deletions. Therefore, how to enhance HDR while suppressing NHEJ is a key to successful applications that require precise genome editing. Histones are small proteins with a lot of basic amino acids that generate electrostatic affinity to DNA. Since H2A.X is involved in DNA repair processes, we fused H2A.X to Cas9 and found that this fusion protein could improve the HDR/NHEJ ratio by suppressing NHEJ. As various post-translational modifications of H2A.X play roles in the regulation of DNA repair, we also fused H2A.X mimicry variants to replicate these post-translational modifications including phosphorylation, methylation, and acetylation. However, none of them were effective to improve the HDR/NHEJ ratio. We further fused other histone variants to Cas9 and found that H2A.1 suppressed NHEJ better than H2A.X. Thus, the fusion of histone variants to Cas9 is a promising option to enhance precise genome editing.
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Affiliation(s)
- Tomoko Kato-Inui
- Tokyo Metropolitan Institute of Medical Science, Regenerative Medicine Project, Tokyo, Japan
| | - Gou Takahashi
- Tokyo Metropolitan Institute of Medical Science, Regenerative Medicine Project, Tokyo, Japan
| | - Terumi Ono
- Tokyo Metropolitan Institute of Medical Science, Regenerative Medicine Project, Tokyo, Japan
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yuichiro Miyaoka
- Tokyo Metropolitan Institute of Medical Science, Regenerative Medicine Project, Tokyo, Japan
- Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
- Graduate School of Humanities and Sciences, Ochanomizu University, Tokyo, Japan
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Nam H, Xie K, Majumdar I, Yang S, Starzyk J, Lee D, Shan R, Li J, Wu H. Engineering Tripartite Gene Editing Machinery for Highly Efficient Non-Viral Targeted Genome Integration. RESEARCH SQUARE 2023:rs.3.rs-3365585. [PMID: 37961210 PMCID: PMC10635301 DOI: 10.21203/rs.3.rs-3365585/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Non-viral DNA donor template has been widely used for targeted genomic integration by homologous recombination (HR). This process has become more efficient with RNA guided endonuclease editor system such as CRISPR/Cas9. Circular single stranded DNA (cssDNA) has been harnessed previously as a genome engineering catalyst (GATALYST) for efficient and safe targeted gene knock-in. Here we developed enGager, a system with enhanced GATALYST associated genome editor, comprising a set of novel genome editors in which the integration efficiency of a circular single-stranded (css) donor DNA is elevated by directly tethering of the cssDNA to a nuclear-localized Cas9 fused with ssDNA binding peptides. Improvements in site-directed genomic integration and expression of a knocked-in DNA encoding GFP were observed at multiple genomic loci in multiple cell lines. The enhancement of integration efficiency, compared to unfused Cas9 editors, ranges from 1.5- to more than 6-fold, with the enhancement most pronounced for transgenes of > 4Kb in length in primary cells. enGager-enhanced genome integration prefers ssDNA donors which, unlike traditional dsDNA donors, are not concatemerized or rearranged prior to and during integration Using an enGager fused to an optimized cssDNA binding peptide, exceptionally efficient, targeted integration of the chimeric antigen receptor (CAR) transgene was achieved in 33% of primary human T cells. Enhanced anti-tumor function of these CAR-T primary cells demonstrated the functional competence of the transgenes. The 'tripartite editors with ssDNA optimized genome engineering' (TESOGENASE™) systems help address the efficacy needs for therapeutic gene modification while avoiding the safety and payload size limitations of viral vectors currently used for CAR-T engineering.
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Affiliation(s)
- Hangu Nam
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States
| | - Keqiang Xie
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
| | - Ishita Majumdar
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
| | - Shaobo Yang
- Department of Bioengineering, Northeastern University, Boston, MA 02115, United States
| | - Jakob Starzyk
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
| | - Danna Lee
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
| | - Richard Shan
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
| | - Jiahe Li
- Department of Biomedical Engineering, College of Engineering and School of Medicine, University of Michigan, Ann Arbor, MI 48109, United States
| | - Hao Wu
- Full Circles Therapeutics, INC. 625 Mount Auburn St., Ste. 105, Cambridge, MA 02138, United States
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Nam H, Xie K, Majumdar I, Yang S, Starzyk J, Lee D, Shan R, Li J, Wu H. TESOGENASE, An Engineered Nuclease Editor for Enhanced Targeted Genome Integration. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.28.553855. [PMID: 37693500 PMCID: PMC10491117 DOI: 10.1101/2023.08.28.553855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Non-viral DNA donor template has been widely used for targeted genomic integration by homologous recombination (HR). This process has become more efficient with RNA guided endonuclease editor system such as CRISPR/Cas9. Circular single stranded DNA (cssDNA) has been harnessed previously as a g enome engineering c atalyst (GATALYST) for efficient and safe targeted gene knock-in. However, the engineering efficiency is bottlenecked by the nucleoplasm trafficking and genomic tethering of cssDNA donor, especially for extra-large transgene integration. Here we developed enGager, en hanced G ATALYST a ssociated g enome e ditor system by fusion of nucleus localization signal (NLS) peptide tagged Cas9 with various single stranded DNA binding protein modules through a GFP reporter Knock-in screening. The enGager system assembles an integrative genome integration machinery by forming tripartite complex for engineered nuclease editors, sgRNA and ssDNA donors, thereby facilitate the nucleus trafficking of DNA donors and increase their active local concentration at the targeted genomic site. When applied for genome integration with cssDNA donor templates to diverse genomic loci in various cell types, these enGagers outperform unfused editors. The enhancement of integration efficiency ranges from 1.5- to more than 6-fold, with the effect being more prominent for > 4Kb transgene knock-in in primary cells. We further demonstrated that enGager mediated enhancement for genome integration is ssDNA, but less dsDNA dependent. Using one of the mini-enGagers, we demonstrated large chimeric antigen receptor (CAR) transgene integration in primary T cells with exceptional efficiency and anti-tumor function. These tripartite e ditors with s sDNA o ptimized g enome en gineering system (TESOGENASE TM ) add a set of novel endonuclease editors into the gene-editing toolbox for potential cell and gene therapeutic development based on ssDNA mediated non-viral genome engineering. Highlight A reporter Knock-in screening establishes enGager system to identify TESOGENASE editor to improving ssDNA mediated genome integrationMini-TESOGENASEs developed by fusing Cas9 nuclease with novel ssDNA binding motifsmRNA mini-TESOGENASEs enhance targeted genome integration via various non-viral delivery approachesEfficient functional CAR-T cell engineering by mini-TESOGENASE.
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Fichter KM, Setayesh T, Malik P. Strategies for precise gene edits in mammalian cells. MOLECULAR THERAPY. NUCLEIC ACIDS 2023; 32:536-552. [PMID: 37215153 PMCID: PMC10192336 DOI: 10.1016/j.omtn.2023.04.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
CRISPR-Cas technologies have the potential to revolutionize genetic medicine. However, work is still needed to make this technology clinically efficient for gene correction. A barrier to making precise genetic edits in the human genome is controlling how CRISPR-Cas-induced DNA breaks are repaired by the cell. Since error-prone non-homologous end-joining is often the preferred cellular repair pathway, CRISPR-Cas-induced breaks often result in gene disruption. Homology-directed repair (HDR) makes precise genetic changes and is the clinically desired pathway, but this repair pathway requires a homology donor template and cycling cells. Newer editing strategies, such as base and prime editing, can affect precise repair for relatively small edits without requiring HDR and circumvent cell cycle dependence. However, these technologies have limitations in the extent of genetic editing and require the delivery of bulky cargo. Here, we discuss the pros and cons of precise gene correction using CRISPR-Cas-induced HDR, as well as base and prime editing for repairing small mutations. Finally, we consider emerging new technologies, such as recombination and transposases, which can circumvent both cell cycle and cellular DNA repair dependence for editing the genome.
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Affiliation(s)
- Katye M. Fichter
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Tahereh Setayesh
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
| | - Punam Malik
- Division of Experimental Hematology and Cancer Biology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
- Division of Hematology, Cancer and Blood Disease Institute, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH 45229, USA
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Aiba W, Amai T, Ueda M, Kuroda K. Improving Precise Genome Editing Using Donor DNA/gRNA Hybrid Duplex Generated by Complementary Bases. Biomolecules 2022; 12:1621. [PMID: 36358971 PMCID: PMC9687273 DOI: 10.3390/biom12111621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 10/19/2022] [Accepted: 10/27/2022] [Indexed: 11/06/2022] Open
Abstract
In precise genome editing, site-specific DNA double-strand breaks (DSBs) induced by the CRISPR/Cas9 system are repaired via homology-directed repair (HDR) using exogenous donor DNA templates. However, the low efficiency of HDR-mediated genome editing is a barrier to widespread use. In this study, we created a donor DNA/guide RNA (gRNA) hybrid duplex (DGybrid) that was composed of sequence-extended gRNA and single-stranded oligodeoxynucleotide (ssODN) combined with complementary bases without chemical modifications to increase the concentration of donor DNA at the cleavage site. The efficiency of genome editing using DGybrid was evaluated in Saccharomyces cerevisiae. The results show a 1.8-fold (from 35% to 62%) improvement in HDR-mediated editing efficiency compared to genome editing in which gRNA and donor DNA were introduced separately. In addition, analysis of the nucleic acid introduction efficiency using flow cytometry indicated that both RNA and ssODNs are efficiently incorporated into cells together by using the DNA/RNA hybrid. Our technique would be preferred as a universal and concise tool for improving the efficiency of HDR-mediated genome editing.
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Affiliation(s)
| | | | | | - Kouichi Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
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Development of an in vivo cleavable donor plasmid for targeted transgene integration by CRISPR-Cas9 and CRISPR-Cas12a. Sci Rep 2022; 12:17775. [PMID: 36272994 PMCID: PMC9588054 DOI: 10.1038/s41598-022-22639-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 10/18/2022] [Indexed: 01/19/2023] Open
Abstract
The CRISPR-Cas system is widely used for genome editing of cultured cells and organisms. The discovery of a new single RNA-guided endonuclease, CRISPR-Cas12a, in addition to the conventional CRISPR-Cas9 has broadened the number of editable target sites on the genome. Here, we developed an in vivo cleavable donor plasmid for precise targeted knock-in of external DNA by both Cas9 and Cas12a. This plasmid, named pCriMGET_9-12a (plasmid of synthetic CRISPR-coded RNA target sequence-equipped donor plasmid-mediated gene targeting via Cas9 and Cas12a), comprises the protospacer-adjacent motif sequences of Cas9 and Cas12a at the side of an off-target free synthetic CRISPR-coded RNA target sequence and a multiple cloning site for donor cassette insertion. pCriMGET_9-12a generates a linearized donor cassette in vivo by both CRISPR-Cas9 and CRISPR-Cas12a, which resulted in increased knock-in efficiency in culture cells. This method also achieved > 25% targeted knock-in of long external DNA (> 4 kb) in mice by both CRISPR-Cas9 and CRISPR-Cas12a. The pCriMGET_9-12a system expands the genomic target space for transgene knock-in and provides a versatile, low-cost, and high-performance CRISPR genome editing tool.
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8
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Zuo Q, Xu W, Wan Y, Feng D, He C, Lin C, Huang D, Chen F, Han L, Sun Q, Chen D, Du H, Huang L. Efficient generation of a CYP3A4-T2A-luciferase knock-in HepaRG subclone and its optimized differentiation. Biomed Pharmacother 2022; 152:113243. [PMID: 35687910 DOI: 10.1016/j.biopha.2022.113243] [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: 04/28/2022] [Revised: 05/30/2022] [Accepted: 06/02/2022] [Indexed: 11/02/2022] Open
Abstract
CRISPR/Cas9 has allowed development of better and easier-to-use ADME models than traditional methods by complete knockout or knock-in of genes. However, gene editing in HepaRG cells remains challenging because long-term monoclonal cultivation may alter their differentiation capacity to a large extent. Here, CRISPR/Cas9 was used to generate a CYP3A4-T2A-luciferase knock-in HepaRG subclone by Cas9-mediated homologous recombination and monoclonal cultivation. The knock-in HepaRG-#9 subclone retained a similar differentiation potential to wildtype HepaRG cells (HepaRG-WT). To further improve differentiation and expand the applications of knock-in HepaRG cells, two optimized differentiation procedures were evaluated by comparison with the standard differentiation procedure using the knock-in HepaRG-#9 subclone and HepaRG-WT. The results indicated that addition of forskolin (an adenylate cyclase activator) and SB431542 (a TGF-β pathway inhibitor) to the first optimized differentiation procedure led to better differentiation consequence in terms of not only the initiation time for differentiation and morphological characterization, but also the mRNA levels of hepatocyte-specific genes. These data may contribute to more extensive applications of genetically modified HepaRG cells in ADME studies.
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Affiliation(s)
- Qingxia Zuo
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Wanqing Xu
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Yanbin Wan
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Dongyan Feng
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Changsheng He
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Cailing Lin
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Dongchao Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Feng Chen
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Liya Han
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Qi Sun
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Dong Chen
- Fangrui Institute of Innovative Drugs, South China University of Technology, Guangzhou 510006, China
| | - Hongli Du
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China
| | - Lizhen Huang
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou 510006, China.
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Finney M, Romanowski J, Adelman ZN. Strategies to improve homology-based repair outcomes following CRISPR-based gene editing in mosquitoes: lessons in how to keep any repair disruptions local. Virol J 2022; 19:128. [PMID: 35908059 PMCID: PMC9338592 DOI: 10.1186/s12985-022-01859-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 07/18/2022] [Indexed: 11/10/2022] Open
Abstract
Programmable gene editing systems such as CRISPR-Cas have made mosquito genome engineering more practical and accessible, catalyzing the development of cutting-edge genetic methods of disease vector control. This progress, however, has been limited by the low efficiency of homology-directed repair (HDR)-based sequence integration at DNA double-strand breaks (DSBs) and a lack of understanding about DSB repair in mosquitoes. Innovative efforts to optimize HDR sequence integration by inhibiting non-homologous end joining or promoting HDR have been performed in mammalian systems, however many of these approaches have not been applied to mosquitoes. Here, we review some of the most relevant steps of DNA DSB repair choice and highlight promising approaches that influence this choice to enhance HDR in the context of mosquito gene editing.
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Affiliation(s)
- Micaela Finney
- Department of Entomology, Texas A&M University, 329A Minnie Belle Heep Center, 370 Olsen Blvd, College Station, TX, 77843, USA
| | - Joseph Romanowski
- Department of Entomology, Texas A&M University, 329A Minnie Belle Heep Center, 370 Olsen Blvd, College Station, TX, 77843, USA
| | - Zach N Adelman
- Department of Entomology, Texas A&M University, 329A Minnie Belle Heep Center, 370 Olsen Blvd, College Station, TX, 77843, USA.
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Small-molecule enhancers of CRISPR-induced homology-directed repair in gene therapy: A medicinal chemist's perspective. Drug Discov Today 2022; 27:2510-2525. [PMID: 35738528 DOI: 10.1016/j.drudis.2022.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 05/19/2022] [Accepted: 06/16/2022] [Indexed: 11/20/2022]
Abstract
CRISPR technologies are increasingly being investigated and utilized for the treatment of human genetic diseases via genome editing. CRISPR-Cas9 first generates a targeted DNA double-stranded break, and a functional gene can then be introduced to replace the defective copy in a precise manner by templated repair via the homology-directed repair (HDR) pathway. However, this is challenging owing to the relatively low efficiency of the HDR pathway compared with a rival random repair pathway known as non-homologous end joining (NHEJ). Small molecules can be employed to increase the efficiency of HDR and decrease that of NHEJ to improve the efficiency of precise knock-in genome editing. This review discusses the potential usage of such small molecules in the context of gene therapy and their drug-likeness, from a medicinal chemist's perspective.
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Validation Study to Determine the Accuracy of Widespread Promoterless EGFP Reporter at Assessing CRISPR/Cas9-Mediated Homology Directed Repair. Curr Issues Mol Biol 2022; 44:1688-1700. [PMID: 35723374 PMCID: PMC9164083 DOI: 10.3390/cimb44040116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/03/2022] [Accepted: 04/06/2022] [Indexed: 11/17/2022] Open
Abstract
An accurate visual reporter system to assess homology-directed repair (HDR) is a key prerequisite for evaluating the efficiency of Cas9-mediated precise gene editing. Herein, we tested the utility of the widespread promoterless EGFP reporter to assess the efficiency of CRISPR/Cas9-mediated homologous recombination by fluorescence expression. We firstly established a promoterless EGFP reporter donor targeting the porcine GAPDH locus to study CRISPR/Cas9-mediated homologous recombination in porcine cells. Curiously, EGFP was expressed at unexpectedly high levels from the promoterless donor in porcine cells, with or without Cas9/sgRNA. Even higher EGFP expression was detected in human cells and those of other species when the porcine donor was transfected alone. Therefore, EGFP could be expressed at certain level in various cells transfected with the promoterless EGFP reporter alone, making it a low-resolution reporter for measuring Cas9-mediated HDR events. In summary, the widespread promoterless EGFP reporter could not be an ideal measurement for HDR screening and there is an urgent need to develop a more reliable, high-resolution HDR screening system to better explore strategies of increasing the efficiency of Cas9-mediated HDR in mammalian cells.
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Ou-Yang H, Yang SH, Chen W, Yang SH, Cidem A, Sung LY, Chen CM. Cruciform DNA Structures Act as Legible Templates for Accelerating Homologous Recombination in Transgenic Animals. Int J Mol Sci 2022; 23:3973. [PMID: 35409332 PMCID: PMC9000021 DOI: 10.3390/ijms23073973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 03/27/2022] [Accepted: 03/29/2022] [Indexed: 11/16/2022] Open
Abstract
Inverted repeat (IR) DNA sequences compose cruciform structures. Some genetic disorders are the result of genome inversion or translocation by cruciform DNA structures. The present study examined whether exogenous DNA integration into the chromosomes of transgenic animals was related to cruciform DNA structures. Large imperfect cruciform structures were frequently predicted around predestinated transgene integration sites in host genomes of microinjection-based transgenic (Tg) animals (αLA-LPH Tg goat, Akr1A1eGFP/eGFP Tg mouse, and NFκB-Luc Tg mouse) or CRISPR/Cas9 gene-editing (GE) animals (αLA-AP1 GE mouse). Transgene cassettes were imperfectly matched with their predestinated sequences. According to the analyzed data, we proposed a putative model in which the flexible cruciform DNA structures acted as a legible template for DNA integration into linear DNAs or double-strand break (DSB) alleles. To demonstrate this model, artificial inverted repeat knock-in (KI) reporter plasmids were created to analyze the KI rate using the CRISPR/Cas9 system in NIH3T3 cells. Notably, the KI rate of the 5′ homologous arm inverted repeat donor plasmid (5′IR) with the ROSA gRNA group (31.5%) was significantly higher than the knock-in reporter donor plasmid (KIR) with the ROSA gRNA group (21.3%, p < 0.05). However, the KI rate of the 3′ inverted terminal repeat/inverted repeat donor plasmid (3′ITRIR) group was not different from the KIR group (23.0% vs. 22.0%). These results demonstrated that the legibility of the sequence with the cruciform DNA existing in the transgene promoted homologous recombination (HR) with a higher KI rate. Our findings suggest that flexible cruciform DNAs folded by IR sequences improve the legibility and accelerate DNA 3′-overhang integration into the host genome via homologous recombination machinery.
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Affiliation(s)
- Huan Ou-Yang
- Program in Translational Medicine, Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (H.O.-Y.); (S.-H.Y.); (A.C.)
- Institute of Biotechnology, College of Bioresources and Agriculture, National Taiwan University, Taipei 106, Taiwan
| | - Shiao-Hsuan Yang
- Program in Translational Medicine, Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (H.O.-Y.); (S.-H.Y.); (A.C.)
- Reproductive Medicine Center, Department of Gynecology, Changhua Christian Hospital, Changhua 515, Taiwan
| | - Wei Chen
- Division of Pulmonary and Critical Care Medicine, Chia-Yi Christian Hospital, Chiayi 600, Taiwan;
| | - Shang-Hsun Yang
- Department of Physiology, National Cheng Kung University, Tainan 701, Taiwan;
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan
| | - Abdulkadir Cidem
- Program in Translational Medicine, Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (H.O.-Y.); (S.-H.Y.); (A.C.)
- Department of Molecular Biology and Genetics, Erzurum Technical University, Erzurum 25250, Turkey
| | - Li-Ying Sung
- Institute of Biotechnology, College of Bioresources and Agriculture, National Taiwan University, Taipei 106, Taiwan
| | - Chuan-Mu Chen
- Program in Translational Medicine, Department of Life Sciences, National Chung Hsing University, Taichung 402, Taiwan; (H.O.-Y.); (S.-H.Y.); (A.C.)
- The iEGG and Animal Biotechnology Center, National Chung Hsing University, Taichung 402, Taiwan
- Rong-Hsing Translational Medicine Research Center, Taichung Veterans General Hospital, Taichung 407, Taiwan
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