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Davison C, Harzman H, Nicholson J, Entriken S, Mobley K, Krull A, Singhal M, Skow C, Matthews N, Kopp L, Gillette B, Weide TJ, Hukvari JR, Stumpf SC, Feldmann OM, McGrail M, Srivastava R, Essner JJ. Tagging the tjp1a Gene in Zebrafish with Monomeric Red Fluorescent Protein Using Biotin Homology Arms. Zebrafish 2024; 21:191-197. [PMID: 38621205 PMCID: PMC11035848 DOI: 10.1089/zeb.2023.0096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/17/2024] Open
Abstract
Tjp1a and other tight junction and adherens proteins play important roles in cell-cell adhesion, scaffolding, and forming seals between cells in epithelial and endothelial tissues. In this study, we labeled Tjp1a of zebrafish with the monomeric red fluorescent protein (mRFP) using CRISPR/Cas9-mediated targeted integration of biotin-labeled polymerase chain reaction (PCR) generated templates. Labeling Tjp1a with RFP allowed us to follow membrane and junctional dynamics of epithelial and endothelial cells throughout zebrafish embryo development. For targeted integration, we used short 35 bp homology arms on each side of the Cas9 genomic target site at the C-terminal of the coding sequence in tjp1a. Through PCR using 5' biotinylated primers containing the homology arms, we generated a double-stranded template for homology directed repair containing a flexible linker followed by RFP. Cas9 protein was complexed with the tjp1a gRNA before mixing with the repair template and microinjected into one-cell zebrafish embryos. We confirmed and recovered a precise integration allele at the desired site at the tjp1a C-terminus. Examination of fluorescence reveals RFP cell-cell junctional labeling using confocal imaging. We are currently using this stable tjp1a-mRFPis86 line to examine the behavior and interactions between cells during vascular formation in zebrafish.
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Affiliation(s)
- Connor Davison
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Hamelynn Harzman
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Jessie Nicholson
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Seth Entriken
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Kierinn Mobley
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Abigail Krull
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Manik Singhal
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Caleb Skow
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Nathan Matthews
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Lindsey Kopp
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Benjamin Gillette
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Tyler J. Weide
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Jana R. Hukvari
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Sofia C.P. Stumpf
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Olivia M. Feldmann
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Maura McGrail
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Renu Srivastava
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
| | - Jeffrey J. Essner
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, Iowa, USA
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2
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Lee Z, Wan J, Shen A, Barnard G. Gene copy number, gene configuration and LC/HC mRNA ratio impact on antibody productivity and product quality in targeted integration CHO cell lines. Biotechnol Prog 2024:e3433. [PMID: 38321634 DOI: 10.1002/btpr.3433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/01/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024]
Abstract
The augmentation of transgene copy numbers is a prevalent approach presumed to enhance transcriptional activity and product yield. CHO cell lines engineered via targeted integration (TI) offer an advantageous platform for investigating the interplay between gene copy number, mRNA abundance, product yield, and product quality. Our investigation revealed that incrementally elevating the gene copy numbers of both IgG heavy chain (HC) and light chain (LC) concurrently resulted in the attainment of plateaus in mRNA levels and product titers, notably occurring beyond four to five gene copies integrated at the same TI site. Furthermore, maintaining a fixed gene copy number while varying the position of genes within the vector influenced the LC/HC mRNA ratio, which subsequently exerted a substantial impact on product titer. Moreover, manipulation of the LC/HC gene ratio through the introduction of surplus LC gene copies led to heightened LC mRNA expression and a reduction in the levels of high molecular weight species. It is noteworthy that the effects of excess LC on product titer were dependent on the specific molecule under consideration. The strategic utilization of PCR tags enabled precise quantification of transcription from each expression slot within the vector, facilitating the identification of highly expressive and less expressive slots. Collectively, these findings significantly enhance our understanding of stable antibody production in TI CHO cell lines.
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Affiliation(s)
- Zion Lee
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Jun Wan
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Amy Shen
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Gavin Barnard
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
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Kovač A, Miskey C, Ivics Z. Sleeping Beauty Transposon Insertions into Nucleolar DNA by an Engineered Transposase Localized in the Nucleolus. Int J Mol Sci 2023; 24:14978. [PMID: 37834425 PMCID: PMC10573994 DOI: 10.3390/ijms241914978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/22/2023] [Accepted: 09/28/2023] [Indexed: 10/15/2023] Open
Abstract
Transposons are nature's gene delivery vehicles that can be harnessed for experimental and therapeutic purposes. The Sleeping Beauty (SB) transposon shows efficient transposition and long-term transgene expression in human cells, and is currently under clinical development for gene therapy. SB transposition occurs into the human genome in a random manner, which carries a risk of potential genotoxic effects associated with transposon integration. Here, we evaluated an experimental strategy to manipulate SB's target site distribution by preferentially compartmentalizing the SB transposase to the nucleolus, which contains repetitive ribosomal RNA (rRNA) genes. We generated a fusion protein composed of the nucleolar protein nucleophosmin (B23) and the SB100X transposase, which was found to retain almost full transposition activity as compared to unfused transposase and to be predominantly localized to nucleoli in transfected human cells. Analysis of transposon integration sites generated by B23-SB100X revealed a significant enrichment into the p-arms of chromosomes containing nucleolus organizing regions (NORs), with preferential integration into the p13 and p11.2 cytobands directly neighboring the NORs. This bias in the integration pattern was accompanied by an enrichment of insertions into nucleolus-associated chromatin domains (NADs) at the periphery of nucleolar DNA and into lamina-associated domains (LADs). Finally, sub-nuclear targeting of the transposase resulted in preferential integration into chromosomal domains associated with the Upstream Binding Transcription Factor (UBTF) that plays a critical role in the transcription of 47S rDNA gene repeats of the NORs by RNA Pol I. Future modifications of this technology may allow the development of methods for specific gene insertion for precision genetic engineering.
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Affiliation(s)
| | | | - Zoltán Ivics
- Transposition and Genome Engineering, Research Centre of the Division of Hematology, Gene and Cell Therapy, Paul Ehrlich Institute, Paul Ehrlich Str. 51–59, D-63225 Langen, Germany; (A.K.); (C.M.)
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4
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Amiri S, Adibzadeh S, Ghanbari S, Rahmani B, Kheirandish MH, Farokhi-Fard A, Dastjerdeh MS, Davami F. CRISPR-interceded CHO cell line development approaches. Biotechnol Bioeng 2023; 120:865-902. [PMID: 36597180 DOI: 10.1002/bit.28329] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 11/28/2022] [Accepted: 01/02/2023] [Indexed: 01/05/2023]
Abstract
For industrial production of recombinant protein biopharmaceuticals, Chinese hamster ovary (CHO) cells represent the most widely adopted host cell system, owing to their capacity to produce high-quality biologics with human-like posttranslational modifications. As opposed to random integration, targeted genome editing in genomic safe harbor sites has offered CHO cell line engineering a new perspective, ensuring production consistency in long-term culture and high biotherapeutic expression levels. Corresponding the remarkable advancements in knowledge of CRISPR-Cas systems, the use of CRISPR-Cas technology along with the donor design strategies has been pushed into increasing novel scenarios in cell line engineering, allowing scientists to modify mammalian genomes such as CHO cell line quickly, readily, and efficiently. Depending on the strategies and production requirements, the gene of interest can also be incorporated at single or multiple loci. This review will give a gist of all the most fundamental recent advancements in CHO cell line development, such as different cell line engineering approaches along with donor design strategies for targeted integration of the desired construct into genomic hot spots, which could ultimately lead to the fast-track product development process with consistent, improved product yield and quality.
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Affiliation(s)
- Shahin Amiri
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Setare Adibzadeh
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Samaneh Ghanbari
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Behnaz Rahmani
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mohammad H Kheirandish
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
- Department of Medical Biotechnology, School of Advanced Technologies, Tehran University of Medical Sciences, Tehran, Iran
| | - Aref Farokhi-Fard
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mansoureh S Dastjerdeh
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Fatemeh Davami
- Department of Medical Biotechnology, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Loh HP, Mahfut FB, Chen SW, Huang Y, Huo J, Zhang W, Lam KP, Xu S, Yang Y. Manufacturability and functionality assessment of different formats of T-cell engaging bispecific antibodies. MAbs 2023; 15:2231129. [PMID: 37403264 DOI: 10.1080/19420862.2023.2231129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/06/2023] Open
Abstract
T-cell-engaging bispecific antibodies (T-bsAbs) are promising immunotherapies for cancer treatment due to their capability of redirecting T-cells toward destroying tumor cells. Numerous T-bsAb formats have been developed, each with advantages and disadvantages in terms of developability, immunogenicity, effector functions, and pharmacokinetics. Here, we systematically compared T-bsAbs produced using eight different formats, evaluating the effect of molecular design of T-bsAbs on their manufacturability and functionality. These eight T-bsAb formats were constructed using antigen-binding fragments (Fabs) and single-chain variable fragments (scFvs) of antibodies linked to the crystallizable fragment (Fc) domain of immunoglobulin G. To ensure a fair comparison of growth and production data, we used recombinase-mediated cassette exchange technology to generate the T-bsAb-producing CHO cell lines. The produced T-bsAbs were assessed for their purification profile and recovery, binding capability, and biological activities. Our findings indicated that the manufacturability of bsAbs was adversely affected with increased number of scFv building blocks, while the functionality was affected by the combination of multiple factors, including the binding affinity and avidity of targeting moieties and the flexibility and geometry of formats. These results provide valuable insights into the impact of the format design on the optimal production and function of T-bsAbs.
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Affiliation(s)
- Han Ping Loh
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Farouq Bin Mahfut
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Serene W Chen
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Yuhan Huang
- Singapore Immunology Network (SIGN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Jianxin Huo
- Singapore Immunology Network (SIGN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Wei Zhang
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
| | - Kong Peng Lam
- Singapore Immunology Network (SIGN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Microbiology and Immunology, Singapore, Singapore
| | - Shengli Xu
- Singapore Immunology Network (SIGN), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
- Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Yuansheng Yang
- Bioprocessing Technology Institute (BTI), Agency for Science, Technology and Research (A*STAR), Singapore, Singapore
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6
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Tang D, Gunson J, Tran E, Lam C, Shen A, Snedecor B, Barnard G, Misaghi S. Expressing antigen binding fragments with high titers in a targeted integration CHO host by optimizing expression vector gene copy numbers and position: A case study. Biotechnol Prog 2022; 38:e3290. [PMID: 36537257 DOI: 10.1002/btpr.3290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 07/15/2022] [Accepted: 07/30/2022] [Indexed: 12/24/2022]
Abstract
Antigen binding fragments (Fab) are a promising class of therapeutics as they maintain high potency while having significantly smaller size relative to full-length antibodies. Because Fab molecules are aglycosylated, many expression platforms, including prokaryotic, yeast, and mammalian cells, have been developed for their expression, with Escherichia coli being the most commonly used Fab expression system. In this study, we have examined production of a difficult to express Fab molecule in a targeted integration (TI) Chinese Hamster Ovary (CHO) host. Without a need for extensive host or process optimization, as is usually required for E. coli, by simply using different vector configurations, clones with very high Fab expression titers were obtained. In this case, by increasing heavy chain (HC) gene copy numbers, clones with titers of up to 7.4 g/L in the standard fed-batch production culture were obtained. Our findings suggest that having a predetermined transgene integration site, as well as the option to optimize gene copy number/dosage, makes CHO TI hosts an effective system for expression of Fab molecules, allowing Fab expression using platform process and without significant process development efforts.
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Affiliation(s)
- Danming Tang
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA.,Protein Sciences, Proteologix US Inc., Redwood Shores, California, USA
| | - Jane Gunson
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Eric Tran
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Cynthia Lam
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Amy Shen
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Brad Snedecor
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Gavin Barnard
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
| | - Shahram Misaghi
- Cell Culture and Bioprocess Operations Department, Genentech Inc., South San Francisco, California, USA
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7
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Pickar-Oliver A, Gough V, Bohning JD, Liu S, Robinson-Hamm JN, Daniels H, Majoros WH, Devlin G, Asokan A, Gersbach CA. Full-length dystrophin restoration via targeted exon integration by AAV-CRISPR in a humanized mouse model of Duchenne muscular dystrophy. Mol Ther 2021; 29:3243-3257. [PMID: 34509668 PMCID: PMC8571168 DOI: 10.1016/j.ymthe.2021.09.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 08/23/2021] [Accepted: 09/05/2021] [Indexed: 12/26/2022] Open
Abstract
Targeted gene-editing strategies have emerged as promising therapeutic approaches for the permanent treatment of inherited genetic diseases. However, precise gene correction and insertion approaches using homology-directed repair are still limited by low efficiencies. Consequently, many gene-editing strategies have focused on removal or disruption, rather than repair, of genomic DNA. In contrast, homology-independent targeted integration (HITI) has been reported to effectively insert DNA sequences at targeted genomic loci. This approach could be particularly useful for restoring full-length sequences of genes affected by a spectrum of mutations that are also too large to deliver by conventional adeno-associated virus (AAV) vectors. Here, we utilize an AAV-based, HITI-mediated approach for correction of full-length dystrophin expression in a humanized mouse model of Duchenne muscular dystrophy (DMD). We co-deliver CRISPR-Cas9 and a donor DNA sequence to insert the missing human exon 52 into its corresponding position within the DMD gene and achieve full-length dystrophin correction in skeletal and cardiac muscle. Additionally, as a proof-of-concept strategy to correct genetic mutations characterized by diverse patient mutations, we deliver a superexon donor encoding the last 28 exons of the DMD gene as a therapeutic strategy to restore full-length dystrophin in >20% of the DMD patient population. This work highlights the potential of HITI-mediated gene correction for diverse DMD mutations and advances genome editing toward realizing the promise of full-length gene restoration to treat genetic disease.
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Affiliation(s)
- Adrian Pickar-Oliver
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Veronica Gough
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Joel D Bohning
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Siyan Liu
- Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA; Graduate Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA
| | - Jacqueline N Robinson-Hamm
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - Heather Daniels
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | - William H Majoros
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA; Center for Statistical Genetics and Genomics, Duke University, Durham, NC 27708, USA; Division of Integrative Genomics, Department of Biostatistics and Bioinformatics, Duke University School of Medicine, Durham, NC 27710, USA
| | - Garth Devlin
- Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA
| | - Aravind Asokan
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Regeneration Next Initiative, Duke University, Durham, NC 27710, USA
| | - Charles A Gersbach
- Department of Biomedical Engineering, Room 1427 FCIEMAS, 101 Science Drive, Box 90281, Duke University, Durham, NC 27708, USA; Center for Advanced Genomic Technologies, Duke University, Durham, NC 27708, USA; Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA; Graduate Program in Computational Biology and Bioinformatics, Duke University, Durham, NC 27708, USA; Department of Surgery, Duke University School of Medicine, Durham, NC 27710, USA; Regeneration Next Initiative, Duke University, Durham, NC 27710, USA; Department of Cell Biology, Duke University Medical Center, Durham, NC 27710, USA.
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8
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Shin S, Kim SH, Lee JS, Lee GM. Streamlined Human Cell-Based Recombinase-Mediated Cassette Exchange Platform Enables Multigene Expression for the Production of Therapeutic Proteins. ACS Synth Biol 2021; 10:1715-1727. [PMID: 34133132 DOI: 10.1021/acssynbio.1c00113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A platform, based on targeted integration of transgenes using recombinase-mediated cassette exchange (RMCE) coupled with CRISPR/Cas9, is increasingly being used for the development of mammalian cell lines that produce therapeutic proteins, because of reduced clonal variation and predictable transgene expression. However, low efficiency of the RMCE process has hampered its application in multicopy or multisite integration of transgenes. To improve RMCE efficiency, nuclear transport of RMCE components such as site-specific recombinase and donor plasmid was accelerated by incorporation of nuclear localization signal and DNA nuclear-targeting sequence, respectively. Consequently, the efficiency of RMCE in dual-landing pad human embryonic kidney 293 (HEK293) cell lines harboring identical or orthogonal pairs of recombination sites at two well-known human safe harbors (AAVS1 and ROSA26 loci), increased 6.7- and 8.1-fold, respectively. This platform with enhanced RMCE efficiency enabled simultaneous integration of transgenes at the two sites using a single transfection without performing selection and enrichment processes. The use of a homotypic dual-landing pad HEK293 cell line capable of incorporating the same transgenes at two sites resulted in a 2-fold increase in the transgene expression level compared to a single-landing pad HEK293 cell line. In addition, the use of a heterotypic dual-landing pad HEK293 cell line, which can incorporate transgenes for a recombinant protein at one site and an effector transgene for cell engineering at another site, increased recombinant protein production. Overall, a streamlined RMCE platform can be a versatile tool for mammalian cell line development by facilitating multigene expression at genomic safe harbors.
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Affiliation(s)
- Seunghyeon Shin
- Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea
| | - Su Hyun Kim
- Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea
| | - Jae Seong Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
| | - Gyun Min Lee
- Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea
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9
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Yoder KE, Rabe AJ, Fishel R, Larue RC. Strategies for Targeting Retroviral Integration for Safer Gene Therapy: Advances and Challenges. Front Mol Biosci 2021; 8:662331. [PMID: 34055882 PMCID: PMC8149907 DOI: 10.3389/fmolb.2021.662331] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/29/2021] [Indexed: 12/11/2022] Open
Abstract
Retroviruses are obligate intracellular parasites that must integrate a copy of the viral genome into the host DNA. The integration reaction is performed by the viral enzyme integrase in complex with the two ends of the viral cDNA genome and yields an integrated provirus. Retroviral vector particles are attractive gene therapy delivery tools due to their stable integration. However, some retroviral integration events may dysregulate host oncogenes leading to cancer in gene therapy patients. Multiple strategies to target retroviral integration, particularly to genetic safe harbors, have been tested with limited success. Attempts to target integration may be limited by the multimerization of integrase or the presence of host co-factors for integration. Several retroviral integration complexes have evolved a mechanism of tethering to chromatin via a host protein. Integration host co-factors bind chromatin, anchoring the complex and allowing integration. The tethering factor allows for both close proximity to the target DNA and specificity of targeting. Each retrovirus appears to have distinct preferences for DNA sequence and chromatin features at the integration site. Tethering factors determine the preference for chromatin features, but do not affect the subtle sequence preference at the integration site. The sequence preference is likely intrinsic to the integrase protein. New developments may uncouple the requirement for a tethering factor and increase the ability to redirect retroviral integration.
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Affiliation(s)
- Kristine E Yoder
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Anthony J Rabe
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Richard Fishel
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH, United States
| | - Ross C Larue
- Department of Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH, United States
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de Alencastro G, Puzzo F, Pavel-Dinu M, Zhang F, Pillay S, Majzoub K, Tiffany M, Jang H, Sheikali A, Cromer MK, Meetei R, Carette JE, Porteus MH, Pekrun K, Kay MA. Improved Genome Editing through Inhibition of FANCM and Members of the BTR Dissolvase Complex. Mol Ther 2021; 29:1016-1027. [PMID: 33678249 DOI: 10.1016/j.ymthe.2020.10.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/27/2020] [Accepted: 10/19/2020] [Indexed: 11/16/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors have the unique property of being able to perform genomic targeted integration (TI) without inducing a double-strand break (DSB). In order to improve our understanding of the mechanism behind TI mediated by AAV and improve its efficiency, we performed an unbiased genetic screen in human cells using a promoterless AAV-homologous recombination (AAV-HR) vector system. We identified that the inhibition of the Fanconi anemia complementation group M (FANCM) protein enhanced AAV-HR-mediated TI efficiencies in different cultured human cells by ∼6- to 9-fold. The combined knockdown of the FANCM and two proteins also associated with the FANCM complex, RecQ-mediated genome instability 1 (RMI1) and Bloom DNA helicase (BLM) from the BLM-topoisomerase IIIα (TOP3A)-RMI (BTR) dissolvase complex (RMI1, having also been identified in our screen), led to the enhancement of AAV-HR-mediated TI up to ∼17 times. AAV-HR-mediated TI in the presence of a nuclease (CRISPR-Cas9) was also increased by ∼1.5- to 2-fold in FANCM and RMI1 knockout cells, respectively. Furthermore, knockdown of FANCM in human CD34+ hematopoietic stem and progenitor cells (HSPCs) increased AAV-HR-mediated TI by ∼3.5-fold. This study expands our knowledge on the mechanisms related to AAV-mediated TI, and it highlights new pathways that might be manipulated for future improvements in AAV-HR-mediated TI.
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Affiliation(s)
| | - Francesco Puzzo
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Mara Pavel-Dinu
- Department of Pediatrics, Division of Stem Cell Transplantation and Regenerative Medicine, Stanford, CA, USA
| | - Feijie Zhang
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Sirika Pillay
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA
| | - Karim Majzoub
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA
| | - Matthew Tiffany
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Hagoon Jang
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Adam Sheikali
- Department of Pediatrics, Division of Stem Cell Transplantation and Regenerative Medicine, Stanford, CA, USA
| | - M Kyle Cromer
- Department of Pediatrics, Division of Stem Cell Transplantation and Regenerative Medicine, Stanford, CA, USA
| | - Ruhikanta Meetei
- Division of Experimental Hematology and Cancer Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Jan E Carette
- Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA
| | - Matthew H Porteus
- Department of Pediatrics, Division of Stem Cell Transplantation and Regenerative Medicine, Stanford, CA, USA
| | - Katja Pekrun
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA
| | - Mark A Kay
- Departments of Pediatrics and Genetics, Stanford University, Stanford, CA, USA.
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11
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Dong E, Lam C, Tang D, Louie S, Yim M, Williams AJ, Sawyer W, Yip S, Carver J, AlBarakat A, Tsukuda J, Snedecor B, Misaghi S. Concurrent transfection of randomized transgene configurations into targeted integration CHO host is an advantageous and cost-effective method for expression of complex molecules. Biotechnol J 2020; 16:e2000230. [PMID: 33259700 DOI: 10.1002/biot.202000230] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 11/20/2020] [Accepted: 11/20/2020] [Indexed: 12/15/2022]
Abstract
Complex recombinant proteins are increasingly desired as potential therapeutic options for many disease indications and are commonly expressed in the mammalian Chinese hamster ovary (CHO) cells. Generally, stoichiometric expression and proper folding of all subunits of a complex recombinant protein are required to achieve the desired titers and product qualities for a complex molecule. Targeted integration (TI) cell line development (CLD), which entails the insertion of the desired transgene(s) into a predefined landing-pad in the CHO genome, enables the generation of a homogeneous pool of cells from which clonally stable and high titer clones can be isolated with minimal screening efforts. Despite these advantages, using a single transgene(s) configuration with predetermined gene dosage might not be adequate for the expression of complex molecules. The goal of this study is to develop a method for seamless screening of many vector configurations in a single TI CLD attempt. As testing vector configurations in transient expression systems is not predictive of protein expression in the stable cell lines and parallel TI CLDs with different transgene configurations is resource-intensive, we tested the concept of randomized configuration targeted integration (RCTI) CLD approach for expression of complex molecules. RCTI allows simultaneous transfection of multiple vector configurations, encoding a complex molecule, to generate diverse TI clones each with a single transgene configuration but clone specific productivity and product qualities. Our findings further revealed a direct correlation between transgenes' configuration/copy-number and titer/product quality of the expressed proteins. RCTI CLD enabled, with significantly fewer resources, seamless isolation of clones with comparable titers and product quality attributes to that of several parallel standard TI CLDs. Therefore, RCTI introduces randomness to the TI CLD platform while maintaining all the advantages, such as clone stability and reduced sequence variant levels, that the TI system has to offer.
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Affiliation(s)
- Emily Dong
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Cynthia Lam
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Danming Tang
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Salina Louie
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Mandy Yim
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Ambrose J Williams
- Purification Development Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - William Sawyer
- Biochemical and Cellular Pharmacology Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Shirley Yip
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Joseph Carver
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Ali AlBarakat
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Joni Tsukuda
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Brad Snedecor
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
| | - Shahram Misaghi
- Cell Culture and Bioprocess Operations Department, Genentech, Inc. 1 DNA Way, South San Francisco, California, USA
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12
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Abstract
The last few years have seen tremendous advances in CRISPR-mediated genome editing. Great efforts have been made to improve the efficiency, specificity, editing window, and targeting scope of CRISPR/Cas9-mediated transgene knock-in and gene correction. In this article, we comprehensively review recent progress in CRISPR-based strategies for targeted transgene knock-in and gene correction in both homology-dependent and homology-independent approaches. We cover homology-directed repair (HDR), synthesis-dependent strand annealing (SDSA), microhomology-mediated end joining (MMEJ), and homology-mediated end joining (HMEJ) pathways for a homology-dependent strategy and alternative DNA repair pathways such as non-homologous end joining (NHEJ), base excision repair (BER), and mismatch repair (MMR) for a homology-independent strategy. We also discuss base editing and prime editing that enable direct conversion of nucleotides in genomic DNA without damaging the DNA or requiring donor DNA. Notably, we illustrate the key mechanisms and design principles for each strategy, providing design guidelines for multiplex, flexible, scarless gene insertion and replacement at high efficiency and specificity. In addition, we highlight next-generation base editors that provide higher editing efficiency, fewer undesired by-products, and broader targeting scope.
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Affiliation(s)
- Cia-Hin Lau
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Chung Tin
- Department of Biomedical Engineering, Academic 1, 83 Tat Chee Avenue, City University of Hong Kong, Hong Kong
| | - Yousin Suh
- Department of Obstetrics and Gynecology, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
- Department of Genetics and Development, Columbia University Irving Medical Center, 630 West 168th Street, New York, NY 10032, USA
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13
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Sergeeva D, Lee GM, Nielsen LK, Grav LM. Multicopy Targeted Integration for Accelerated Development of High-Producing Chinese Hamster Ovary Cells. ACS Synth Biol 2020; 9:2546-2561. [PMID: 32835482 DOI: 10.1021/acssynbio.0c00322] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ever-growing biopharmaceutical industry relies on the production of recombinant therapeutic proteins in Chinese hamster ovary (CHO) cells. The traditional timelines of CHO cell line development can be significantly shortened by the use of targeted gene integration (TI). However, broad use of TI has been limited due to the low specific productivity (qP) of TI-generated clones. Here, we show a 10-fold increase in the qP of therapeutic glycoproteins in CHO cells through the development and optimization of a multicopy TI method. We used a recombinase-mediated cassette exchange (RMCE) platform to investigate the effect of gene copy number, 5' and 3' gene regulatory elements, and landing pad features on qP. We evaluated the limitations of multicopy expression from a single genomic site as well as multiple genomic sites and found that a transcriptional bottleneck can appear with an increase in gene dosage. We created a dual-RMCE system for simultaneous multicopy TI in two genomic sites and generated isogenic high-producing clones with qP of 12-14 pg/cell/day and product titer close to 1 g/L in fed-batch. Our study provides an extensive characterization of the multicopy TI method and elucidates the relationship between gene copy number and protein expression in mammalian cells. Moreover, it demonstrates that TI-generated CHO cells are capable of producing therapeutic proteins at levels that can support their industrial manufacture.
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Affiliation(s)
- Daria Sergeeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
| | - Gyun Min Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
- Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea
| | - Lars Keld Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Brisbane 4072, Australia
| | - Lise Marie Grav
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby 2800, Denmark
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14
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Wang Q, Zhong X, Li Q, Su J, Liu Y, Mo L, Deng H, Yang Y. CRISPR-Cas9-Mediated In Vivo Gene Integration at the Albumin Locus Recovers Hemostasis in Neonatal and Adult Hemophilia B Mice. Mol Ther Methods Clin Dev 2020; 18:520-531. [PMID: 32775489 PMCID: PMC7393320 DOI: 10.1016/j.omtm.2020.06.025] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 06/25/2020] [Indexed: 02/05/2023]
Abstract
Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 loaded by vectors could induce high rates of specific site genome editing and correct disease-causing mutations. However, most monogenic genetic diseases such as hemophilia are caused by different mutations dispersed in one gene, instead of an accordant mutation. Vectors developed for correcting specific mutations may not be suited to different mutations at other positions. Site-specific gene addition provides an ideal solution for long-term, stable gene therapy. We have demonstrated SaCas9-mediated homology-directed factor IX (FIX) in situ targeting for sustained treatment of hemophilia B. In this study, we tested a more efficient dual adeno-associated virus (AAV) strategy with lower vector dose for liver-directed genome editing that enables CRISPR-Cas9-mediated site-specific integration of therapeutic transgene within the albumin gene, and we aimed to develop a more universal gene-targeting approach. We successfully achieved coagulation function in newborn and adult hemophilia B mice by a single injection of dual AAV vectors. FIX levels in treated mice persisted even after a two-thirds partial hepatectomy, indicating stable gene integration. Our results suggest that this CRISPR-Cas9-mediated site-specific gene integration in hepatocytes could transform into a common clinical therapeutic method for hemophilia B and other genetic diseases.
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Affiliation(s)
- Qingnan Wang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Xiaomei Zhong
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Qian Li
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Jing Su
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Yi Liu
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Li Mo
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Hongxin Deng
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
| | - Yang Yang
- State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Chengdu 610041, China
- Corresponding author: Yang Yang, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, Sichuan University and Collaborative Innovation Center, Ke-yuan Road 4, No. 1, Gao-peng Street, Chengdu, Sichuan 610041, China.
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15
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Schenkwein D, Afzal S, Nousiainen A, Schmidt M, Ylä-Herttuala S. Efficient Nuclease-Directed Integration of Lentivirus Vectors into the Human Ribosomal DNA Locus. Mol Ther 2020; 28:1858-1875. [PMID: 32504545 PMCID: PMC7403359 DOI: 10.1016/j.ymthe.2020.05.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 04/03/2020] [Accepted: 05/19/2020] [Indexed: 12/30/2022] Open
Abstract
Lentivirus vectors (LVs) are efficient tools for gene transfer, but the non-specific nature of transgene integration by the viral integration machinery carries an inherent risk for genotoxicity. We modified the integration machinery of LVs and harnessed the cellular DNA double-strand break repair machinery to integrate transgenes into ribosomal DNA, a promising genomic safe-harbor site for transgenes. LVs carrying modified I-PpoI-derived homing endonuclease proteins were characterized in detail, and we found that at least 21% of all integration sites localized to ribosomal DNA when LV transduction was coupled to target DNA cleavage. In addition to the primary sequence recognized by the endonuclease, integration was also enriched in chromatin domains topologically associated with nucleoli, which contain the targeted ribosome RNA genes. Targeting of this highly repetitive region for integration was not associated with detectable DNA deletions or negative impacts on cell health in transduced primary human T cells. The modified LVs characterized here have an overall lower risk for insertional mutagenesis than regular LVs and can thus improve the safety of gene and cellular therapy.
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Affiliation(s)
- Diana Schenkwein
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
| | - Saira Afzal
- Department of Translational Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany
| | - Alisa Nousiainen
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland
| | - Manfred Schmidt
- Department of Translational Oncology, National Center for Tumor Diseases (NCT) and German Cancer Research Center (DKFZ), Im Neuenheimer Feld 581, 69120 Heidelberg, Germany; GeneWerk GmbH, Im Neuenheimer Feld 582, 69120 Heidelberg, Germany
| | - Seppo Ylä-Herttuala
- A.I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, P.O. Box 1627, FIN-70211 Kuopio, Finland; Heart Center and Gene Therapy Unit, Kuopio University Hospital, P.O. Box 1777, FIN-70211 Kuopio, Finland.
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16
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Abstract
Numerous engineering efforts have been made in Chinese hamster ovary (CHO) cells for high level production of therapeutic proteins. However, the dynamic regulation of transgene expression is limited in current systems. Here, we investigated the effective regulation of transgene expression in CHO cells via targeted integration-based endogenous gene tagging with engineering target genes. Targeted integration of EGFP-human Bcl-2 into the p21 locus effectively reduced the apoptosis, compared with random populations in which Bcl-2 expression was driven by cytomegalovirus (CMV) promoter. Endogenous p21 and EGFP-human Bcl-2 displayed similar expression dynamics in batch cultures, and the antiapoptotic effect altered the expression pattern of endogenous p21 showing the mutual influences between expression of p21 and Bcl-2. We further demonstrated the inducible transgene expression by adding low concentrations of hydroxyurea. The present engineering strategy will provide a valuable CHO cell engineering tool that can be used to control dynamic transgene expression in accordance with cellular states.
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Affiliation(s)
- Youngsik Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
| | - Jin Myeong Kwak
- Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon 16499, Republic of Korea
| | - Jae Seong Lee
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
- Department of Applied Chemistry and Biological Engineering, Ajou University, Suwon 16499, Republic of Korea
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17
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Shin SW, Lee JS. Optimized CRISPR/Cas9 strategy for homology-directed multiple targeted integration of transgenes in CHO cells. Biotechnol Bioeng 2020; 117:1895-1903. [PMID: 32086804 DOI: 10.1002/bit.27315] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 12/12/2022]
Abstract
Site-specific integration has emerged as a promising strategy for precise Chinese hamster ovary (CHO) cell line engineering and predictable cell line development (CLD). CRISPR/Cas9 with the homology-directed repair (HDR) pathway enables precise integration of transgenes into target genomic sites. However, inherent recalcitrance to HDR-mediated targeted integration (TI) of transgenes results in low targeting efficiency, thus requiring a selection process to find a targeted integrant in CHO cells. Here, we explored several parameters that influence the targeting efficiency using a promoter-trap-based single- or double-knock-in (KI) monitoring system. A simple change in the donor template design by the addition of single-guide RNA recognition sequences strongly increased KI efficiency (2.9-36.0 fold), depending on integration sites and cell culture mode, compared to conventional circular donor plasmids. Furthermore, sequential and simultaneous KI strategies enabled us to obtain populations with ~1-4% of double-KI cells without additional enrichment procedures. Thus, this simple optimized strategy not only allows efficient CRISPR/Cas9-mediated TI in CHO cells but also paves the way for the applicability of multiplexed KIs in one experimental step without the need for sequential and independent CHO-CLD procedures.
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Affiliation(s)
- Sung Wook Shin
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
| | - Jae Seong Lee
- Department of Molecular Science and Technology, Ajou University, Suwon, Republic of Korea
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18
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Wierson WA, Welker JM, Almeida MP, Mann CM, Webster DA, Torrie ME, Weiss TJ, Kambakam S, Vollbrecht MK, Lan M, McKeighan KC, Levey J, Ming Z, Wehmeier A, Mikelson CS, Haltom JA, Kwan KM, Chien CB, Balciunas D, Ekker SC, Clark KJ, Webber BR, Moriarity BS, Solin SL, Carlson DF, Dobbs DL, McGrail M, Essner J. Efficient targeted integration directed by short homology in zebrafish and mammalian cells. eLife 2020; 9:e53968. [PMID: 32412410 PMCID: PMC7228771 DOI: 10.7554/elife.53968] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 04/22/2020] [Indexed: 12/14/2022] Open
Abstract
Efficient precision genome engineering requires high frequency and specificity of integration at the genomic target site. Here, we describe a set of resources to streamline reporter gene knock-ins in zebrafish and demonstrate the broader utility of the method in mammalian cells. Our approach uses short homology of 24-48 bp to drive targeted integration of DNA reporter cassettes by homology-mediated end joining (HMEJ) at high frequency at a double strand break in the targeted gene. Our vector series, pGTag (plasmids for Gene Tagging), contains reporters flanked by a universal CRISPR sgRNA sequence which enables in vivo liberation of the homology arms. We observed high rates of germline transmission (22-100%) for targeted knock-ins at eight zebrafish loci and efficient integration at safe harbor loci in porcine and human cells. Our system provides a straightforward and cost-effective approach for high efficiency gene targeting applications in CRISPR and TALEN compatible systems.
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MESH Headings
- Animals
- Animals, Genetically Modified
- CRISPR-Associated Proteins/genetics
- CRISPR-Associated Proteins/metabolism
- CRISPR-Cas Systems
- Clustered Regularly Interspaced Short Palindromic Repeats
- Fibroblasts/metabolism
- Gene Expression Regulation
- Gene Knock-In Techniques
- Genes, Reporter
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Humans
- K562 Cells
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/genetics
- Leukemia, Myelogenous, Chronic, BCR-ABL Positive/metabolism
- RNA, Guide, CRISPR-Cas Systems/genetics
- RNA, Guide, CRISPR-Cas Systems/metabolism
- Recombinational DNA Repair
- Sequence Homology, Nucleic Acid
- Sus scrofa
- Transcription Activator-Like Effector Nucleases/genetics
- Transcription Activator-Like Effector Nucleases/metabolism
- Zebrafish/genetics
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Affiliation(s)
- Wesley A Wierson
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Jordan M Welker
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Maira P Almeida
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Carla M Mann
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | | | - Melanie E Torrie
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Trevor J Weiss
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Sekhar Kambakam
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | | | - Merrina Lan
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Kenna C McKeighan
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Jacklyn Levey
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Zhitao Ming
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Alec Wehmeier
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Christopher S Mikelson
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Jeffrey A Haltom
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Kristen M Kwan
- Department of Human Genetics, University of Utah School of MedicineSalt Lake CityUnited States
| | - Chi-Bin Chien
- Department of Neurobiology and Anatomy, University of Utah Medical CenterSalt Lake CityUnited States
| | - Darius Balciunas
- Department of Biology, Temple UniversityPhiladelphiaUnited States
| | - Stephen C Ekker
- Department of Biochemistry and Molecular Biology, Mayo ClinicRochesterUnited States
| | - Karl J Clark
- Department of Biochemistry and Molecular Biology, Mayo ClinicRochesterUnited States
| | - Beau R Webber
- Department of Pediatrics, Masonic Cancer Center, University of MinnesotaMinneapolisUnited States
| | - Branden S Moriarity
- Department of Pediatrics, Masonic Cancer Center, University of MinnesotaMinneapolisUnited States
| | | | | | - Drena L Dobbs
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Maura McGrail
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
| | - Jeffrey Essner
- Department of Genetics, Development and Cell Biology, Iowa State UniversityAmesUnited States
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19
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Abstract
Genome editing of hematopoietic stem cells (HSCs) represents a therapeutic option for a number of hematological genetic diseases, as HSCs have the potential for self-renewal and differentiation into all blood cell lineages. This review presents advances of genome editing in HSCs utilizing adenovirus vectors as delivery vehicles. We focus on capsid-modified, helper-dependent adenovirus vectors that are devoid of all viral genes and therefore exhibit an improved safety profile. We discuss HSC genome engineering for several inherited disorders and infectious diseases including hemoglobinopathies, Fanconi anemia, hemophilia, and HIV-1 infection by ex vivo and in vivo editing in transgenic mice, nonhuman primates, as well as in human CD34+ cells. Mechanisms of therapeutic gene transfer including episomal expression of designer nucleases and base editors, transposase-mediated random integration, and targeted homology-directed repair triggered integration into selected genomic safe harbor loci are also reviewed.
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Affiliation(s)
- Chang Li
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, USA
| | - André Lieber
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, USA
- Department of Pathology, University of Washington, Seattle, WA, USA
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20
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Li C, Mishra AS, Gil S, Wang M, Georgakopoulou A, Papayannopoulou T, Hawkins RD, Lieber A. Targeted Integration and High-Level Transgene Expression in AAVS1 Transgenic Mice after In Vivo HSC Transduction with HDAd5/35++ Vectors. Mol Ther 2019; 27:2195-2212. [PMID: 31494053 DOI: 10.1016/j.ymthe.2019.08.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/10/2019] [Accepted: 08/14/2019] [Indexed: 12/16/2022] Open
Abstract
Our goal is the development of in vivo hematopoietic stem cell (HSC) transduction technology with targeted integration. To achieve this, we modified helper-dependent HDAd5/35++ vectors to express a CRISPR/Cas9 specific to the "safe harbor" adeno-associated virus integration site 1 (AAVS1) locus and to provide a donor template for targeted integration through homology-dependent repair. We tested the HDAd-CRISPR + HDAd-donor vector system in AAVS1 transgenic mice using a standard ex vivo HSC gene therapy approach as well as a new in vivo HSC transduction approach that involves HSC mobilization and intravenous HDAd5/35++ injections. In both settings, the majority of treated mice had transgenes (GFP or human γ-globin) integrated into the AAVS1 locus. On average, >60% of peripheral blood cells expressed the transgene after in vivo selection with low-dose O6BG/bis-chloroethylnitrosourea (BCNU). Ex vivo and in vivo HSC transduction and selection studies with HDAd-CRISPR + HDAd-globin-donor resulted in stable γ-globin expression at levels that were significantly higher (>20% γ-globin of adult mouse globin) than those achieved in previous studies with a SB100x-transposase-based HDAd5/35++ system that mediates random integration. The ability to achieve therapeutically relevant transgene expression levels after in vivo HSC transduction and selection and targeted integration make our HDAd5/35++-based vector system a new tool in HSC gene therapy.
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Affiliation(s)
- Chang Li
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | - Arpit Suresh Mishra
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | - Sucheol Gil
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | - Meng Wang
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | - Aphrodite Georgakopoulou
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | | | - R David Hawkins
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA
| | - André Lieber
- Division of Medical Genetics, Department of Medicine, University of Washington, Box 357720, Seattle, WA 98195, USA; Department of Pathology, University of Washington, Box 357720, Seattle, WA 98195, USA.
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21
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Lee JS, Park JH, Ha TK, Samoudi M, Lewis NE, Palsson BO, Kildegaard HF, Lee GM. Revealing Key Determinants of Clonal Variation in Transgene Expression in Recombinant CHO Cells Using Targeted Genome Editing. ACS Synth Biol 2018; 7:2867-2878. [PMID: 30388888 DOI: 10.1021/acssynbio.8b00290] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Generation of recombinant Chinese hamster ovary (rCHO) cell lines is critical for the production of therapeutic proteins. However, the high degree of phenotypic heterogeneity among generated clones, referred to as clonal variation, makes the rCHO cell line development process inefficient and unpredictable. Here, we investigated the major genomic causes of clonal variation. We found the following: (1) consistent with previous studies, a strong variation in rCHO clones in response to hypothermia (33 vs 37 °C) after random transgene integration; (2) altered DNA sequence of randomly integrated cassettes, which occurred during the integration process, affecting the transgene expression level in response to hypothermia; (3) contrary to random integration, targeted integration of the same expression cassette, without any DNA alteration, into three identified integration sites showed the similar response of transgene expression in response to hypothermia, irrespective of integration site; (4) switching the promoter from CMV to EF1α eliminated the hypothermia response; and (5) deleting the enhancer part of the CMV promoter altered the hypothermia response. Thus, we have revealed the effects of integration methods and cassette design on transgene expression levels, implying that rCHO cell line generation can be standardized through detailed genomic understanding. Further elucidation of such understanding is likely to have a broad impact on diverse fields that use transgene integration, from gene therapy to generation of production cell lines.
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Affiliation(s)
- Jae Seong Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
| | - Jin Hyoung Park
- Department of Biological Sciences, KAIST, 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Tae Kwang Ha
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Mojtaba Samoudi
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, United States
- The Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, La Jolla, California 92093, United States
| | - Nathan E. Lewis
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, United States
- The Novo Nordisk Foundation Center for Biosustainability at the University of California, San Diego School of Medicine, La Jolla, California 92093, United States
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Bernhard O. Palsson
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, United States
- Department of Bioengineering, University of California, San Diego, La Jolla, California 92093, United States
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Gyun Min Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Biological Sciences, KAIST, 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea
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22
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Grav LM, Sergeeva D, Lee JS, Marin de Mas I, Lewis NE, Andersen MR, Nielsen LK, Lee GM, Kildegaard HF. Minimizing Clonal Variation during Mammalian Cell Line Engineering for Improved Systems Biology Data Generation. ACS Synth Biol 2018; 7:2148-2159. [PMID: 30060646 DOI: 10.1021/acssynbio.8b00140] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mammalian cells are widely used to express genes for basic biology studies and biopharmaceuticals. Current methods for generation of engineered cell lines introduce high genomic and phenotypic diversity, which hamper studies of gene functions and discovery of novel cellular mechanisms. Here, we minimized clonal variation by integrating a landing pad for recombinase-mediated cassette exchange site-specifically into the genome of CHO cells using CRISPR and generated subclones expressing four different recombinant proteins. The subclones showed low clonal variation with high consistency in growth, transgene transcript levels and global transcriptional response to recombinant protein expression, enabling improved studies of the impact of transgenes on the host transcriptome. Little variation over time in subclone phenotypes and transcriptomes was observed when controlling environmental culture conditions. The platform enables robust comparative studies of genome engineered CHO cell lines and can be applied to other mammalian cells for diverse biological, biomedical and biotechnological applications.
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Affiliation(s)
- Lise Marie Grav
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Daria Sergeeva
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Jae Seong Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Molecular Science and Technology, Ajou University, Suwon 16499, Republic of Korea
| | - Igor Marin de Mas
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Nathan E. Lewis
- Department of Pediatrics, University of California, San Diego, La Jolla, California 92093, United States
- The Novo Nordisk Foundation Center for Biosustatainability, University of California, San Diego, La Jolla, California 92093, United States
| | - Mikael Rørdam Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Lars Keld Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, QLD 4072, Australia
| | - Gyun Min Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
- Department of Biological Sciences, KAIST, Daejeon 34141, Republic of Korea
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
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23
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Gao D, Smith S, Spagnuolo M, Rodriguez G, Blenner M. Dual CRISPR-Cas9 Cleavage Mediated Gene Excision and Targeted Integration in Yarrowia lipolytica. Biotechnol J 2018; 13:e1700590. [PMID: 29809313 DOI: 10.1002/biot.201700590] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 05/23/2018] [Indexed: 12/12/2022]
Abstract
CRISPR-Cas9 technology has been successfully applied in Yarrowia lipolytica for targeted genomic editing including gene disruption and integration; however, disruptions by existing methods typically result from small frameshift mutations caused by indels within the coding region, which usually resulted in unnatural protein. In this study, a dual cleavage strategy directed by paired sgRNAs is developed for gene knockout. This method allows fast and robust gene excision, demonstrated on six genes of interest. The targeted regions for excision vary in length from 0.3 kb up to 3.5 kb and contain both non-coding and coding regions. The majority of the gene excisions are repaired by perfect nonhomologous end-joining without indel. Based on this dual cleavage system, two targeted markerless integration methods are developed by providing repair templates. While both strategies are effective, homology mediated end joining (HMEJ) based method are twice as efficient as homology recombination (HR) based method. In both cases, dual cleavage leads to similar or improved gene integration efficiencies compared to gene excision without integration. This dual cleavage strategy will be useful for not only generating more predictable and robust gene knockout, but also for efficient targeted markerless integration, and simultaneous knockout and integration in Y. lipolytica.
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Affiliation(s)
- Difeng Gao
- Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
| | - Spencer Smith
- Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
| | - Michael Spagnuolo
- Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
| | - Gabriel Rodriguez
- Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
| | - Mark Blenner
- Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
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24
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El Ashkar S, Van Looveren D, Schenk F, Vranckx LS, Demeulemeester J, De Rijck J, Debyser Z, Modlich U, Gijsbers R. Engineering Next-Generation BET-Independent MLV Vectors for Safer Gene Therapy. Mol Ther Nucleic Acids 2017. [PMID: 28624199 PMCID: PMC5415309 DOI: 10.1016/j.omtn.2017.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Retroviral vectors have shown their curative potential in clinical trials correcting monogenetic disorders. However, therapeutic benefits were compromised due to vector-induced dysregulation of cellular genes and leukemia development in a subset of patients. Bromodomain and extraterminal domain (BET) proteins act as cellular cofactors that tether the murine leukemia virus (MLV) pre-integration complex to host chromatin via interaction with the MLV integrase (IN) and thereby define the typical gammaretroviral integration distribution. We engineered next-generation BET-independent (Bin) MLV vectors to retarget their integration to regions where they are less likely to dysregulate nearby genes. We mutated MLV IN to uncouple BET protein interaction and fused it with chromatin-binding peptides. The addition of the CBX1 chromodomain to MLV INW390A efficiently targeted integration away from gene regulatory elements. The retargeted vector produced at high titers and efficiently transduced CD34+ hematopoietic stem cells, while fewer colonies were detected in a serial colony-forming assay, a surrogate test for genotoxicity. Our findings underscore the potential of the engineered vectors to reduce the risk of insertional mutagenesis without compromising transduction efficiency. Ultimately, combined with other safety features in vector design, next-generation BinMLV vectors can improve the safety of gammaretroviral vectors for gene therapy.
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Affiliation(s)
- Sara El Ashkar
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Dominique Van Looveren
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Franziska Schenk
- RG Gene Modification in Stem Cells, LOEWE Center for Cell and Gene Therapy Frankfurt, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Lenard S Vranckx
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Jonas Demeulemeester
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Jan De Rijck
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Ute Modlich
- RG Gene Modification in Stem Cells, LOEWE Center for Cell and Gene Therapy Frankfurt, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Rik Gijsbers
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium; Leuven Viral Vector Core, KU Leuven, 3000 Leuven, Belgium.
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25
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Ahmadi M, Mahboudi F, Akbari Eidgahi MR, Nasr R, Nematpour F, Ahmadi S, Ebadat S, Aghaeepoor M, Davami F. Evaluating the efficiency of phiC31 integrase-mediated monoclonal antibody expression in CHO cells. Biotechnol Prog 2016; 32:1570-1576. [PMID: 27604579 DOI: 10.1002/btpr.2362] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 07/19/2016] [Indexed: 01/02/2023]
Abstract
Traditional methods to generate CHO cell lines rely on random integration(s) of the gene of interest and result in unpredictable and unstable protein expression. In comparison, site-specific recombination methods increase the recombinant protein expression by inserting transgene at a locus with specific expression features. PhiC31 serine integrase, catalyze unidirectional integration that occurs at higher frequency in comparison with the reversible integration carried out by recombinases such as Cre. In this study, using different ratios of phiC31 serine integrase, we evaluated the phiC31 mediated gene integration for expression of a humanized IgG1 antibody (mAb0014) in CHO-S cells. Light chain (LC) and heavy chain (HC) genes were expressed in one operon under EF1α promoter and linked by internal ribosome entry site (IRES) element. The clonal selection was carried out by limiting dilution. Targeted integration approach increased recombinant protein yield and stability in cell pools. The productivity of targeted cell pools was about 4 mg/L and about 40 µg/L in the control cell pool. The number of integrated transgenes was about 19 fold higher than the control cells pools. Our results confirmed that the phiC31 integrase leads to mAb expression in more than 90% of colonies. The productivity of the PhiC31 integrated cell pools was stable for three months in the absence of selection as compared with conventional transfection methods. Hence, utilizing PhiC31 integrase can increase protein titer and decrease the required time for protein expression. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1570-1576, 2016.
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Affiliation(s)
- Maryam Ahmadi
- Medical Biotechnology Dept., Semnan University of Medical Sciences, Semnan, Iran.,Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | | | | | - Reza Nasr
- Medical Biotechnology Dept., Semnan University of Medical Sciences, Semnan, Iran
| | - Fatemeh Nematpour
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Samira Ahmadi
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Saeedeh Ebadat
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Mojtaba Aghaeepoor
- Medical Biotechnology Dept., Semnan University of Medical Sciences, Semnan, Iran
| | - Fatemeh Davami
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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26
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Lee JS, Grav LM, Pedersen LE, Lee GM, Kildegaard HF. Accelerated homology-directed targeted integration of transgenes in Chinese hamster ovary cells via CRISPR/Cas9 and fluorescent enrichment. Biotechnol Bioeng 2016; 113:2518-23. [PMID: 27159230 DOI: 10.1002/bit.26002] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 05/02/2016] [Accepted: 05/04/2016] [Indexed: 12/29/2022]
Abstract
Targeted gene integration into site-specific loci can be achieved in Chinese hamster ovary (CHO) cells via CRISPR/Cas9 genome editing technology and the homology-directed repair (HDR) pathway. The low efficiency of HDR often requires antibiotic selection, which limits targeted integration of multiple genes at multiple sites. To improve HDR-mediated targeted integration, while avoiding the use of selection markers, chemical treatment for increased HDR, and fluorescent enrichment of genome-edited cells was assessed in CHO cells. Chemical treatment did not improve HDR-mediated targeted integration. In contrast, fluorescent markers in Cas9 and donor constructs enable FACS enrichment, resulting in a threefold increase in the number of cells with HDR-mediated genome editing. Combined with this enrichment method, large transgenes encoding model proteins (including an antibody) were successfully targeted integrated. This approach provides a simple and fast strategy for targeted generation of stable CHO production cell lines in a rational way. Biotechnol. Bioeng. 2016;113: 2518-2523. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Jae Seong Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, 2970, Denmark
| | - Lise Marie Grav
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, 2970, Denmark
| | - Lasse Ebdrup Pedersen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, 2970, Denmark
| | - Gyun Min Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, 2970, Denmark.,Department of Biological Sciences, KAIST, Yuseong-gu, Daejeon, Republic of Korea
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, 2970, Denmark.
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27
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Abstract
A chromodomain is a domain contained in various proteins involved in chromatin remodeling and the regulation of gene expression in eukaryotes during development. Chromodomains perform a wide range of diverse functions including chromatin targeting and interactions between different proteins, RNA and DNA. The chromodomains also have been found as an additional domain at the C-terminal region of Polyproteins (Pol) encoded by transposable elements, which belong to the Gypsy LTR retrotransposons superfamily. Chromoviruses or chromodomain-containing Gypsy LTR retrotransposons form the most widespread clade of Gypsy LTR retrotransposons and can be found in diverse eukaryotes including plants, fungi and vertebrates. The recent finding suggested that chromodomains can be responsible for the targeted integration of LTR retrotransposons and, thus, should be favorable for mobile elements by allowing them to avoid negative selection arising from insertion into coding regions.
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Affiliation(s)
- Olga Novikova
- Institute of Cytology and Genetics SB RAS; Novosibirsk, Russia
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28
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Müther N, Noske N, Ehrhardt A. Viral hybrid vectors for somatic integration - are they the better solution? Viruses 2009; 1:1295-324. [PMID: 21994594 PMCID: PMC3185507 DOI: 10.3390/v1031295] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 12/04/2009] [Accepted: 12/10/2009] [Indexed: 12/18/2022] Open
Abstract
The turbulent history of clinical trials in viral gene therapy has taught us important lessons about vector design and safety issues. Much effort was spent on analyzing genotoxicity after somatic integration of therapeutic DNA into the host genome. Based on these findings major improvements in vector design including the development of viral hybrid vectors for somatic integration have been achieved. This review provides a state-of-the-art overview of available hybrid vectors utilizing viruses for high transduction efficiencies in concert with various integration machineries for random and targeted integration patterns. It discusses advantages but also limitations of each vector system.
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Affiliation(s)
- Nadine Müther
- Max von Pettenkofer-Institut, Department of Virology, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 9A, 80336 Munich, Germany
| | - Nadja Noske
- Max von Pettenkofer-Institut, Department of Virology, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 9A, 80336 Munich, Germany
| | - Anja Ehrhardt
- Max von Pettenkofer-Institut, Department of Virology, Ludwig-Maximilians-Universität Munich, Pettenkoferstr. 9A, 80336 Munich, Germany
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29
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Abstract
Bähler et al.(1998) recently described a PCR-based system for the deletion, tagging and overexpression of endogenous genes in the fission yeast Schizosaccharomyces pombe. A small set of PCR primers can be used to generate gene-targeting substrates from each of several modules that differ in the selectable marker (ura4(+) or kanMX6), the presence or absence of specific epitope tags (HA, Myc, GST or GFP), the position in which the epitopes will be inserted (C- or N-terminal), and the presence or absence of a regulatable promoter (the nmt1 promoter). This is a straightforward and powerful system: nine different genes were C-terminal tagged at an average efficiency of 73%, using primers producing only 60-81 bp of homology. In contrast, when studying three transcriptionally-silent genes (rec8(+), rec10(+) and rec11(+)) we obtained an average homologous integration efficiency of 4% for 12 targeting constructs when using primers that contained 80 bp of homology. By using a PCR-based increase in the amount of flanking homology to >/=250 bp, we obtained homologous integration efficiencies of up to 100%. Thus, loci of S. pombe that are refractory to gene targeting when using short tracts of homology can be readily modified by increasing the extent of homology flanking the targeting modules. This straightforward and cost-effective approach might therefore be the one of choice for the modification of S. pombe loci in general and of targeting-refractory loci in particular.
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Affiliation(s)
- MICHELLE D. KRAWCHUK
- Department of Biochemistry, Vanderbilt University School of Medicine, 621 Light Hall, Nashville, TN 37232-0146, U.S.A
| | - WAYNE P. WAHLS
- Department of Biochemistry, Vanderbilt University School of Medicine, 621 Light Hall, Nashville, TN 37232-0146, U.S.A
- Correspondence to: W. P. Wahls, Department of Biochemistry, Vanderbilt University School of Medicine, 621 Light Hall, Nashville, TN 37232-0146, U.S.A. Tel: (615) 322-3063; fax: (615) 343-0704;
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