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Shi S, Hamann CA, Lee JC, Brunger JM. Use of CRISPRoff and synthetic Notch to modulate and relay endogenous gene expression programs in engineered cells. Front Bioeng Biotechnol 2024; 12:1346810. [PMID: 38957576 PMCID: PMC11218679 DOI: 10.3389/fbioe.2024.1346810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 05/27/2024] [Indexed: 07/04/2024] Open
Abstract
Uncovering the stimulus-response histories that give rise to cell fates and behaviors is an area of great interest in developmental biology, tissue engineering, and regenerative medicine. A comprehensive accounting of cell experiences that lead to the development of organs and tissues can help us to understand developmental anomalies that may underly disease. Perhaps more provocatively, such a record can also reveal clues as to how to drive cell collective decision-making processes, which may yield predictable cell-based therapies or facilitate production of tissue substitutes for transplantation or in vitro screening of prospective therapies to mitigate disease. Toward this end, various methods have been applied to molecularly trace developmental trajectories and record interaction histories of cells. Typical methods involve artificial gene circuits based on recombinases that activate a suite of fluorescent reporters or CRISPR-Cas9 genome writing technologies whose nucleic acid-based record keeping serves to chronicle cell-cell interactions or past exposure to stimuli of interests. Exciting expansions of the synthetic biology toolkit with artificial receptors that permit establishment of defined input-to-output linkages of cell decision-making processes opens the door to not only record cell-cell interactions, but to also potentiate directed manipulation of the outcomes of such interactions via regulation of carefully selected transgenes. Here, we combine CRISPR-based strategies to genetically and epigenetically manipulate cells to express components of the synthetic Notch receptor platform, a widely used artificial cell signaling module. Our approach gives rise to the ability to conditionally record interactions between human cells, where the record of engagement depends on expression of a state-specific marker of a subset of cells in a population. Further, such signal-competent interactions can be used to direct differentiation of human embryonic stem cells toward pre-selected fates based on assigned synNotch outputs. We also implemented CRISPR-based manipulation of native gene expression profiles to bias outcomes of cell engagement histories in a targeted manner. Thus, we present a useful strategy that gives rise to both state-specific recording of cell-cell interactions as well as methods to intentionally influence products of such cell-cell exchanges.
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Affiliation(s)
- Shuqun Shi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Catherine A. Hamann
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Joanne C. Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
| | - Jonathan M. Brunger
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, United States
- Center for Stem Cell Biology, Vanderbilt University, Nashville, TN, United States
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Kandarakov OF, Polyakova NS, Petrovskaya AV, Bruter AV, Belyavsky AV. CD52/FLAG and CD52/HA Fusion Proteins as Novel Magnetic Cell Selection Markers. Int J Mol Sci 2024; 25:6353. [PMID: 38928060 PMCID: PMC11203882 DOI: 10.3390/ijms25126353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 06/03/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
At present, the magnetic selection of genetically modified cells is mainly performed with surface markers naturally expressed by cells such as CD4, LNGFR (low affinity nerve growth factor receptor), and MHC class I molecule H-2Kk. The disadvantage of such markers is the possibility of their undesired and poorly predictable expression by unmodified cells before or after cell manipulation, which makes it essential to develop new surface markers that would not have such a drawback. Earlier, modified CD52 surface protein variants with embedded HA and FLAG epitope tags (CD52/FLAG and CD52/HA) were developed by the group of Dr. Mazurov for the fluorescent cell sorting of CRISPR-modified cells. In the current study, we tested whether these markers can be used for the magnetic selection of transduced cells. For this purpose, appropriate constructs were created in MigR1-based bicistronic retroviral vectors containing EGFP and DsRedExpress2 as fluorescent reporters. Cytometric analysis of the transduced NIH 3T3 cell populations after magnetic selection evaluated the efficiency of isolation and purity of the obtained populations, as well as the change in the median fluorescence intensity (MFI). The results of this study demonstrate that the surface markers CD52/FLAG and CD52/HA can be effectively used for magnetic cell selection, and their efficiencies are comparable to that of the commonly used LNGFR marker. At the same time, the significant advantage of these markers is the absence of HA and FLAG epitope sequences in cellular proteins, which rules out the spurious co-isolation of negative cells.
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Affiliation(s)
- Oleg F. Kandarakov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia; (O.F.K.); (N.S.P.); (A.V.P.)
| | - Natalia S. Polyakova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia; (O.F.K.); (N.S.P.); (A.V.P.)
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Vavilov Str. 32, 119991 Moscow, Russia;
| | - Alexandra V. Petrovskaya
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia; (O.F.K.); (N.S.P.); (A.V.P.)
| | - Alexandra V. Bruter
- Center for Precision Genome Editing and Genetic Technologies for Biomedicine, Vavilov Str. 32, 119991 Moscow, Russia;
- Institute of Gene Biology, Russian Academy of Sciences, Vavilov Str. 34/5, 119334 Moscow, Russia
| | - Alexander V. Belyavsky
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilov Str. 32, 119991 Moscow, Russia; (O.F.K.); (N.S.P.); (A.V.P.)
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Cheng J, Zhang Y, Tian Y, Cao L, Liu X, Miao S, Zhao L, Ye Q, Zhou Y, Tan WS. Development of a novel tyrosine-based selection system for generation of recombinant Chinese hamster ovary cells. J Biosci Bioeng 2024; 137:221-229. [PMID: 38220502 DOI: 10.1016/j.jbiosc.2023.12.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 12/18/2023] [Accepted: 12/18/2023] [Indexed: 01/16/2024]
Abstract
Efficiently expanding Chinese hamster ovary (CHO) cells, which serve as the primary host cells for recombinant protein production, have gained increasing industrial significance. A significant hurdle in stable cell line development is the low efficiency of the target gene integrated into the host genome, implying the necessity for an effective screening and selection procedure to separate these stable cells. In this study, the genes of phenylalanine hydroxylase (PAH) and pterin 4 alpha carbinolamine dehydratase 1 (PCBD1), which are key enzymes in the tyrosine synthesis pathway, were utilized as selection markers and transduced into host cells together with the target genes. This research investigated the enrichment effect of this system and advanced further in understanding its benefits for cell line development and rCHO cell culture. A novel tyrosine-based selection system that only used PCBD1 as a selection marker was designed to promote the enrichment effect. Post 9 days of starvation, positive transductants in the cell pool approached 100%. Applied the novel tyrosine-based selection system, rCHO cells expressing E2 protein were generated and named CHO TS cells. It could continue to grow, and the yield of E2 achieved 95.95 mg/L in a tyrosine-free and chemically-defined (CD) medium. Herein, we introduced an alternative to antibiotic-based selections for the establishment of CHO cell lines and provided useful insights for the design and development of CD medium.
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Affiliation(s)
- Jun Cheng
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yanmin Zhang
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yuan Tian
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Lei Cao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Xuping Liu
- Shanghai BioEngine Sci-Tech Co., Ltd, Shanghai 201203, China
| | - Shiwei Miao
- Hangzhou Sumgen Biotech Co., Ltd., Hangzhou 310051, China
| | - Liang Zhao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Qian Ye
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.
| | - Yan Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Wen-Song Tan
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
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Ma Y, Deng B, He R, Huang P. Advancements of 3D bioprinting in regenerative medicine: Exploring cell sources for organ fabrication. Heliyon 2024; 10:e24593. [PMID: 38318070 PMCID: PMC10838744 DOI: 10.1016/j.heliyon.2024.e24593] [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: 10/09/2023] [Revised: 01/02/2024] [Accepted: 01/10/2024] [Indexed: 02/07/2024] Open
Abstract
3D bioprinting has unlocked new possibilities for generating complex and functional tissues and organs. However, one of the greatest challenges lies in selecting the appropriate seed cells for constructing fully functional 3D artificial organs. Currently, there are no cell sources available that can fulfill all requirements of 3D bioprinting technologies, and each cell source possesses unique characteristics suitable for specific applications. In this review, we explore the impact of different 3D bioprinting technologies and bioink materials on seed cells, providing a comprehensive overview of the current landscape of cell sources that have been used or hold potential in 3D bioprinting. We also summarized key points to guide the selection of seed cells for 3D bioprinting. Moreover, we offer insights into the prospects of seed cell sources in 3D bioprinted organs, highlighting their potential to revolutionize the fields of tissue engineering and regenerative medicine.
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Affiliation(s)
| | | | - Runbang He
- State Key Laboratory of Advanced Medical Materials and Devices, Engineering Research Center of Pulmonary and Critical Care Medicine Technology and Device (Ministry of Education), Institute of Biomedical Engineering, Tianjin Institutes of Health Science, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, 300192, China
| | - Pengyu Huang
- State Key Laboratory of Advanced Medical Materials and Devices, Engineering Research Center of Pulmonary and Critical Care Medicine Technology and Device (Ministry of Education), Institute of Biomedical Engineering, Tianjin Institutes of Health Science, Chinese Academy of Medical Science & Peking Union Medical College, Tianjin, 300192, China
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Dunuweera AN, Dunuweera SP, Ranganathan K. A Comprehensive Exploration of Bioluminescence Systems, Mechanisms, and Advanced Assays for Versatile Applications. Biochem Res Int 2024; 2024:8273237. [PMID: 38347947 PMCID: PMC10861286 DOI: 10.1155/2024/8273237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 10/10/2023] [Accepted: 01/21/2024] [Indexed: 02/15/2024] Open
Abstract
Bioluminescence has been a fascinating natural phenomenon of light emission from living creatures. It happens when the enzyme luciferase facilitates the oxidation of luciferin, resulting in the creation of an excited-state species that emits light. Although there are many bioluminescent systems, few have been identified. D-luciferin-dependent systems, coelenterazine-dependent systems, Cypridina luciferin-based systems, tetrapyrrole-based luciferins, bacterial bioluminescent systems, and fungal bioluminescent systems are natural bioluminescent systems. Since different bioluminescence systems, such as various combinations of luciferin-luciferase pair reactions, have different light emission wavelengths, they benefit industrial applications such as drug discovery, protein-protein interactions, in vivo imaging in small animals, and controlling neurons. Due to the expression of luciferase and easy permeation of luciferin into most cells and tissues, bioluminescence assays are applied nowadays with modern technologies in most cell and tissue types. It is a versatile technique in a variety of biomedical research. Furthermore, there are some investigated blue-sky research projects, such as bioluminescent plants and lamps. This review article is mainly based on the theory of diverse bioluminescence systems and their past, present, and future applications.
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Affiliation(s)
| | | | - K. Ranganathan
- Department of Botany, University of Jaffna, Jaffna 40000, Sri Lanka
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5-Azacytidine-Mediated Modulation of the Immune Microenvironment in Murine Acute Myeloid Leukemia. Cancers (Basel) 2022; 15:cancers15010118. [PMID: 36612115 PMCID: PMC9817798 DOI: 10.3390/cancers15010118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/20/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
Cancer cells accumulate epigenetic modifications that allow escape from intrinsic and extrinsic surveillance mechanisms. In the case of acute myeloid leukemias (AML) and myelodysplastic syndromes, agents that disrupt chromatin structure, namely hypomethylating agents (HMAs), have shown tremendous promise as an alternate, milder treatment option for older, clinically non-fit patients. HMAs reprogram the epigenetic landscape in tumor cells through the reversal of DNA hypermethylation. Therapeutic effects resulting from these epigenetic changes are incredibly effective, sometimes resulting in complete remissions, but are frequently lost due to primary or acquired resistance. In this study, we describe syngeneic murine leukemias that are responsive to the HMA 5-azacytidine (5-Aza), as determined by augmented expression of a transduced luciferase reporter. We also found that 5-Aza treatment re-established immune-related transcript expression, suppressed leukemic burden and extended survival in leukemia-challenged mice. The effects of 5-Aza treatment were short-lived, and analysis of the immune microenvironment reveals possible mechanisms of resistance, such as simultaneous increase in immune checkpoint protein expression. This represents a model system that is highly responsive to HMAs and recapitulates major therapeutic outcomes observed in human leukemia (relapse) and may serve as a pre-clinical tool for studying acquired resistance and novel treatment combinations.
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Partial Disturbance of Microprocessor Function in Human Stem Cells Carrying a Heterozygous Mutation in the DGCR8 Gene. Genes (Basel) 2022; 13:genes13111925. [DOI: 10.3390/genes13111925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/14/2022] [Accepted: 10/20/2022] [Indexed: 11/04/2022] Open
Abstract
Maturation of microRNAs (miRNAs) begins by the “Microprocessor” complex, containing the Drosha endonuclease and its partner protein, "DiGeorge Syndrome Critical Region 8" (DGCR8). Although the main function of the two proteins is to coordinate the first step of precursor miRNAs formation, several studies revealed their miRNA-independent functions in other RNA-related pathways (e.g., in snoRNA decay) or, for the DGCR8, the role in tissue development. To investigate the specific roles of DGCR8 in various cellular pathways, we previously established a human embryonic stem-cell (hESC) line carrying a monoallelic DGCR8 mutation by using the CRISPR-Cas9 system. In this study, we genetically characterized single-cell originated progenies of the cell line and showed that DGCR8 heterozygous mutation results in only a modest effect on the mRNA level but a significant decrease at the protein level. Self-renewal and trilineage differentiation capacity of these hESCs were not affected by the mutation. However, partial disturbance of the Microprocessor function could be revealed in pri-miRNA processing along the human chromosome 19 miRNA cluster in several clones. With all these studies, we can demonstrate that the mutant hESC line is a good model to study not only miRNA-related but also other “noncanonical” functions of the DGCR8 protein.
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Effects of ubiquitous chromatin opening element (UCOE) on recombinant anti-TNFα antibody production and expression stability in CHO-DG44 cells. Cytotechnology 2022; 74:31-49. [PMID: 35185284 PMCID: PMC8817031 DOI: 10.1007/s10616-021-00503-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/17/2021] [Indexed: 02/03/2023] Open
Abstract
To date, the production of antibodies (mAbs) usually faces the risks of transgene expression reduction and instability, especially after long-time culture. The inclusion of ubiquitous chromatin opening element (UCOE) into expression vectors was reported to enhance protein production and maintain transgene expression stability in CHO cell lines. Thus, we investigate the effects of UCOE on recombinant monoclonal anti-TNFα antibody (mAbTNFα) production and expression stability in CHO-DG44 cells. In our study, non-UCOE and UCOE-based vectors encoding mAbTNFα were constructed and introduced into the CHO-DG44 cells. Cell pools and single-cell clones were obtained by selecting transfected cells with G418, amplifying them by treatment with methotrexate (MTX), and isolating them by limiting dilution. The effects of UCOE on mAb production and stable transgene expression in transfected cells were analyzed via the correlation between mAb yields and mRNA expression level variations, and gene copy number changes. The UCOE pool exhibited higher mAb yield compared to non-UCOE pool. The UCOE was associated with higher transgene transcriptional activity, leading to improvement of mAb production after MTX-mediated gene amplification. The incorporation of UCOE generated cells allowed isolation of greater numbers of positive clones with higher expression. Despite the slightly decreased mAb yield, UCOE clones still retain stable long-term expression in the absence of selective pressure, which was explained by the loss of transgene copies rather than due to the decline of transcriptional activity. In addition, the purified mAb had primary chemical and biological characteristics similar to those of adalimumab. The results showed that the incorporation of UCOE within vectors provides significant advantages in the generation of high-producing clones, enhancement of mAb production, and improvement of gene expression stability.
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Chong ZX, Yeap SK, Ho WY. Transfection types, methods and strategies: a technical review. PeerJ 2021; 9:e11165. [PMID: 33976969 PMCID: PMC8067914 DOI: 10.7717/peerj.11165] [Citation(s) in RCA: 100] [Impact Index Per Article: 33.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 03/05/2021] [Indexed: 12/17/2022] Open
Abstract
Transfection is a modern and powerful method used to insert foreign nucleic acids into eukaryotic cells. The ability to modify host cells' genetic content enables the broad application of this process in studying normal cellular processes, disease molecular mechanism and gene therapeutic effect. In this review, we summarized and compared the findings from various reported literature on the characteristics, strengths, and limitations of various transfection methods, type of transfected nucleic acids, transfection controls and approaches to assess transfection efficiency. With the vast choices of approaches available, we hope that this review will help researchers, especially those new to the field, in their decision making over the transfection protocol or strategy appropriate for their experimental aims.
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Affiliation(s)
- Zhi Xiong Chong
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
| | - Swee Keong Yeap
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, Selangor, Malaysia
| | - Wan Yong Ho
- School of Pharmacy, University of Nottingham Malaysia, Semenyih, Selangor, Malaysia
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Yeong MY, Cheow PS, Abdullah S, Song AAL, Lei-Rossmann J, Tan TK, Yusoff K, Chia SL. Development of a T7 RNA polymerase expressing cell line using lentivirus vectors for the recovery of recombinant Newcastle disease virus. J Virol Methods 2021; 291:114099. [PMID: 33592218 DOI: 10.1016/j.jviromet.2021.114099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 02/02/2021] [Accepted: 02/08/2021] [Indexed: 11/28/2022]
Abstract
The development of a T7 RNA polymerase (T7 RNAP) expressing cell line i.e. BSR T7/5 cells marks an improvement of reverse genetics for the recovery of recombinant Newcastle disease virus (rNDV). BSR T7/5 is developed by transient transfection of plasmid encoding T7 RNAP gene for rNDV rescue. However, the gene expression decreases gradually over multiple passages and eventually hinders the rescue of rNDV. To address this issue, lentiviral vector was used to develop T7 RNAP-expressing HEK293-TA (HEK293-TA-Lv-T7) and SW620 (SW620-Lv-T7) cell lines, evidenced by the expression of T7 RNAP after subsequent 20 passages. rNDV was rescued successfully using HEK293-TA-Lv-T7 clones (R1D3, R1D8, R5B9) and SW620-Lv-T7 clones (R1C11, R3C5) by reverse transfection, yielding comparable virus rescue efficiency and virus titres to that of BSR T7/5. This study provides new tools for rNDV rescue and insights into cell line development and virology by reverse genetics.
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Affiliation(s)
- Ming Yue Yeong
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
| | - Pheik-Sheen Cheow
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
| | - Syahril Abdullah
- UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
| | - Adelene Ai-Lian Song
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
| | - Janet Lei-Rossmann
- Anticancer Viruses and Cancer Vaccines Research Group, Department of Oncology, University of Oxford, OX3 7DQ, Oxford, United Kingdom.
| | - Tiong-Kit Tan
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, OX3 9DS, Oxford, United Kingdom.
| | - Khatijah Yusoff
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia; UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia; Malaysia Genome Institute, Ministry of Science, Technology and Innovation, Jalan Bangi, 43000 Kajang, Selangor Darul Ehsan, Malaysia.
| | - Suet-Lin Chia
- Department of Microbiology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia; UPM-MAKNA Cancer Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor Darul Ehsan, Malaysia.
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Rogers LC, Zhou J, Baker A, Schutt CR, Panda PK, Van Tine BA. Intracellular arginine-dependent translation sensor reveals the dynamics of arginine starvation response and resistance in ASS1-negative cells. Cancer Metab 2021; 9:4. [PMID: 33478587 PMCID: PMC7818940 DOI: 10.1186/s40170-021-00238-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 01/04/2021] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Many cancers silence the metabolic enzyme argininosuccinate synthetase 1 (ASS1), the rate-limiting enzyme for arginine biosynthesis within the urea cycle. Consequently, ASS1-negative cells are susceptible to depletion of extracellular arginine by PEGylated arginine deiminase (ADI-PEG20), an agent currently being developed in clinical trials. As the primary mechanism of resistance to arginine depletion is re-expression of ASS1, we sought a tool to understand the temporal emergence of the resistance phenotype at the single-cell level. METHODS A real-time, single-cell florescence biosensor was developed to monitor arginine-dependent protein translation. The versatile, protein-based sensor provides temporal information about the metabolic adaptation of cells, as it is able to quantify and track individual cells over time. RESULTS Every ASS1-deficient cell analyzed was found to respond to arginine deprivation by decreased expression of the sensor, indicating an absence of resistance in the naïve cell population. However, the temporal recovery and emergence of resistance varied widely amongst cells, suggesting a heterogeneous metabolic response. The sensor also enabled determination of a minimal arginine concentration required for its optimal translation. CONCLUSIONS The translation-dependent sensor developed here is able to accurately track the development of resistance in ASS1-deficient cells treated with ADI-PEG20. Its ability to track single cells over time allowed the determination that resistance is not present in the naïve population, as well as elucidating the heterogeneity of the timing and extent of resistance. This tool represents a useful advance in the study of arginine deprivation, while its design has potential to be adapted to other amino acids.
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Affiliation(s)
- Leonard C Rogers
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA
| | - Jing Zhou
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA.,The First Affiliated Hospital of Nanchang University, Nanchang, 330006, Jiangxi, China
| | - Adriana Baker
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA.,University of Nevada, Las Vegas, Las Vegas, NV, 89154, USA
| | - Charles R Schutt
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA
| | - Prashanta K Panda
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA
| | - Brian A Van Tine
- Division of Medical Oncology, Washington University in St. Louis, St. Louis, Missouri, 63110, USA. .,Division of Pediatric Hematology/Oncology, St. Louis Children's Hospital, St. Louis, MO, 63110, USA. .,Siteman Cancer Center, St. Louis, MO, 63110, USA.
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12
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Liu J, Ge Y, Wang N, Wen J, Wang W, Zeng B, Chen GL. A Simple and Efficient Method to Generate Gene-Knockout and Transgenic Cell Lines. DNA Cell Biol 2020; 40:239-246. [PMID: 33395371 DOI: 10.1089/dna.2020.6183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Knockout (KO) or exogenous expression of a gene of interest in cultured cells is one of the most important ways to study the function of the gene. Compared with transient transfection, stable cell lines possess great advantages such as excellent cell homogeneity and feasibility for long-term use. However, technical challenges in generating stable cell lines still exist in many laboratories using conventional techniques like limiting dilution or cloning cylinders. In this study we describe an optimized method to efficiently create stable cell lines for functional studies. This method was successfully used to generate a PIEZO1 gene-KO cell line with the CRISPR/Cas9 technology, and TRPC5/GCaMP6f-mCherry-coexpressing cell lines without antibiotic selection. Monoclonal cell lines can be obtained in 2-4 weeks after transfection. This method does not require any special equipment or consumables and can be conducted in all laboratories with general cell-culture facility.
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Affiliation(s)
- Jieyu Liu
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Yan Ge
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Na Wang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Jing Wen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Wei Wang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
| | - Gui-Lan Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, Sichuan, China
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Vocelle D, Chesniak OM, Smith MR, Chan C, Walton SP. Kinetic analysis of the intracellular processing of siRNAs by confocal microscopy. Microscopy (Oxf) 2020; 69:401-407. [PMID: 32525202 DOI: 10.1093/jmicro/dfaa031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 05/20/2020] [Accepted: 06/07/2020] [Indexed: 11/14/2022] Open
Abstract
Here, we describe a method for tracking intracellular processing of small interfering RNA (siRNA) containing complexes using automated microscopy controls and image acquisition to minimize user effort and time. This technique uses fluorescence colocalization to monitor dual-labeled fluorescent siRNAs delivered by silica nanoparticles in different intracellular locations, including the early/late endosomes, fast/slow recycling endosomes, lysosomes and the endoplasmic reticulum. Combining the temporal association of siRNAs with each intracellular location, we reconstructed the intracellular pathways used in siRNA processing, and demonstrate how these pathways vary based on the chemical composition of the delivery vehicle.
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Affiliation(s)
- Daniel Vocelle
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S Shaw Lane, East Lansing, MI 48824, USA
| | - Olivia M Chesniak
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Milton R Smith
- Department of Chemistry, Michigan State University, 578 S Shaw Lane, East Lansing, MI 48824, USA
| | - Christina Chan
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S Shaw Lane, East Lansing, MI 48824, USA.,Department of Biochemistry and Molecular Biology, Michigan State University, 603 Wilson Road, East Lansing, MI 48824, USA
| | - S Patrick Walton
- Department of Chemical Engineering and Materials Science, Michigan State University, 428 S Shaw Lane, East Lansing, MI 48824, USA
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14
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Henkel L, Rauscher B, Schmitt B, Winter J, Boutros M. Genome-scale CRISPR screening at high sensitivity with an empirically designed sgRNA library. BMC Biol 2020; 18:174. [PMID: 33228647 PMCID: PMC7686728 DOI: 10.1186/s12915-020-00905-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 10/20/2020] [Indexed: 12/22/2022] Open
Abstract
Background In recent years, large-scale genetic screens using the CRISPR/Cas9 system have emerged as scalable approaches able to interrogate gene function with unprecedented efficiency and specificity in various biological contexts. By this means, functional dependencies on both the protein-coding and noncoding genome of numerous cell types in different organisms have been interrogated. However, screening designs vary greatly and criteria for optimal experimental implementation and library composition are still emerging. Given their broad utility in functionally annotating genomes, the application and interpretation of genome-scale CRISPR screens would greatly benefit from consistent and optimal design criteria. Results We report advantages of conducting viability screens in selected Cas9 single-cell clones in contrast to Cas9 bulk populations. We further systematically analyzed published CRISPR screens in human cells to identify single-guide (sg) RNAs with consistent high on-target and low off-target activity. Selected guides were collected in a novel genome-scale sgRNA library, which efficiently identifies core and context-dependent essential genes. Conclusion We show how empirically designed libraries in combination with an optimized experimental design increase the dynamic range in gene essentiality screens at reduced library coverage. Supplementary information The online version contains supplementary material available at 10.1186/s12915-020-00905-1.
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Affiliation(s)
- Luisa Henkel
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Heidelberg University, BioQuant and Medical Faculty Mannheim, D-69120, Heidelberg, Germany
| | - Benedikt Rauscher
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Heidelberg University, BioQuant and Medical Faculty Mannheim, D-69120, Heidelberg, Germany
| | - Barbara Schmitt
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Heidelberg University, BioQuant and Medical Faculty Mannheim, D-69120, Heidelberg, Germany
| | - Jan Winter
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Heidelberg University, BioQuant and Medical Faculty Mannheim, D-69120, Heidelberg, Germany
| | - Michael Boutros
- German Cancer Research Center (DKFZ), Division Signaling and Functional Genomics and Heidelberg University, BioQuant and Medical Faculty Mannheim, D-69120, Heidelberg, Germany.
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15
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Sun T, Kwok WC, Chua KJ, Lo TM, Potter J, Yew WS, Chesnut JD, Hwang IY, Chang MW. Development of a Proline-Based Selection System for Reliable Genetic Engineering in Chinese Hamster Ovary Cells. ACS Synth Biol 2020; 9:1864-1872. [PMID: 32470293 DOI: 10.1021/acssynbio.0c00221] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Chinese hamster ovary (CHO) cells are the superior host cell culture models used for the bioproduction of therapeutic proteins. One of the prerequisites for bioproduction using CHO cell lines is the need to generate stable CHO cell lines with optimal expression output. Antibiotic selection is commonly employed to isolate and select CHO cell lines with stable expression, despite its potential negative impact on cellular metabolism and expression level. Herein, we present a novel proline-based selection system for the isolation of stable CHO cell lines. The system exploits a dysfunctional proline metabolism pathway in CHO cells by using a pyrroline-5-carboxylate synthase gene as a selection marker, enabling selection to be made using proline-free media. The selection system was demonstrated by expressing green fluorescent protein (GFP) and a monoclonal antibody. When GFP was expressed, more than 90% of stable transfectants were enriched within 2 weeks of the selection period. When a monoclonal antibody was expressed, we achieved comparable titers (3.35 ± 0.47 μg/mL) with G418 and Zeocin-based selections (1.65 ± 0.46 and 2.25 ± 0.07 μg/mL, respectively). We further developed a proline-based coselection by using S. cerevisiae PRO1 and PRO2 genes as markers, which enables the generation of 99.5% double-transgenic cells. The proline-based selection expands available selection tools and provides an alternative to antibiotic-based selections in CHO cell line development.
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Affiliation(s)
- Tao Sun
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Wee Chiew Kwok
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Koon Jiew Chua
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Tat-Ming Lo
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Jason Potter
- Thermo Fisher Scientific, 5781 Van Allen Way, Carlsbad, California 92008, United States
| | - Wen Shan Yew
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Jonathan D. Chesnut
- Thermo Fisher Scientific, 5781 Van Allen Way, Carlsbad, California 92008, United States
| | - In Young Hwang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
| | - Matthew Wook Chang
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
- NUS Synthetic Biology for Clinical and Technological Innovation (SynCTI), National University of Singapore, Singapore 117456, Singapore
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16
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George J, Kahlke T, Abbriano RM, Kuzhiumparambil U, Ralph PJ, Fabris M. Metabolic Engineering Strategies in Diatoms Reveal Unique Phenotypes and Genetic Configurations With Implications for Algal Genetics and Synthetic Biology. Front Bioeng Biotechnol 2020; 8:513. [PMID: 32582656 PMCID: PMC7290003 DOI: 10.3389/fbioe.2020.00513] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 04/30/2020] [Indexed: 12/23/2022] Open
Abstract
Diatoms are photosynthetic microeukaryotes that dominate phytoplankton populations and have increasing applicability in biotechnology. Uncovering their complex biology and elevating strains to commercial standards depends heavily on robust genetic engineering tools. However, engineering microalgal genomes predominantly relies on random integration of transgenes into nuclear DNA, often resulting in detrimental “position-effects” such as transgene silencing, integration into transcriptionally-inactive regions, and endogenous sequence disruption. With the recent development of extrachromosomal transgene expression via independent episomes, it is timely to investigate both strategies at the phenotypic and genomic level. Here, we engineered the model diatom Phaeodactylum tricornutum to produce the high-value heterologous monoterpenoid geraniol, which, besides applications as fragrance and insect repellent, is a key intermediate of high-value pharmaceuticals. Using high-throughput phenotyping we confirmed the suitability of episomes for synthetic biology applications and identified superior geraniol-yielding strains following random integration. We used third generation long-read sequencing technology to generate a complete analysis of all transgene integration events including their genomic locations and arrangements associated with high-performing strains at a genome-wide scale with subchromosomal detail, never before reported in any microalga. This revealed very large, highly concatenated insertion islands, offering profound implications on diatom functional genetics and next generation genome editing technologies, and is key for developing more precise genome engineering approaches in diatoms, including possible genomic safe harbour locations to support high transgene expression for targeted integration approaches. Furthermore, we have demonstrated that exogenous DNA is not integrated inadvertently into the nuclear genome of extrachromosomal-expression clones, an important characterisation of this novel engineering approach that paves the road to synthetic biology applications.
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Affiliation(s)
- Jestin George
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Tim Kahlke
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Raffaela M Abbriano
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | | | - Peter J Ralph
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia
| | - Michele Fabris
- University of Technology Sydney, Climate Change Cluster, Faculty of Science, Ultimo, NSW, Australia.,CSIRO Synthetic Biology Future Science Platform, Brisbane, QLD, Australia
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17
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Hosseini ES, Nikkhah M, Hamidieh AA, Fearnhead HO, Concordet JP, Hosseinkhani S. The Lumiptosome, an engineered luminescent form of the apoptosome can report cell death by using the same Apaf-1 dependent pathway. J Cell Sci 2020; 133:133/10/jcs242636. [DOI: 10.1242/jcs.242636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 02/28/2020] [Indexed: 01/09/2023] Open
Abstract
ABSTRACT
Detection of the apoptosis signature becomes central in understanding cell death modes. We present here a whole-cell biosensor that detects Apaf-1 association and apoptosome formation using a split-luciferase complementary assay. Fusion of N-terminal (Nluc) and C-terminal (Cluc)-fragments of firefly luciferase to the N-terminus of human Apaf-1 was performed in HEK293 cells by using CRISPR-Cas9 technology. This resulted in a luminescent form of the apoptosome that we named ‘Lumiptosome’. During Apaf-1 gene editing, a high number of knock-in events were observed without selection, suggesting that the Apaf-1 locus is important for the integration of exogenous transgenes. Since activation of caspase-9 is directly dependent on the apoptosome formation, measured reconstitution of luciferase activity should result from the cooperative association of Nluc-Apaf-1 and Cluc-Apaf-1. Time-response measurements also confirmed that formation of the apoptosome occurs prior to activation of caspase-3. Additionally, overexpression of the Bcl2 apoptosis regulator in transgenic and normal HEK293 cells confirmed that formation of the Lumiptosome depends on release of cytochrome c. Thus, HEK293 cells that stably express the Lumiptosome can be utilized to screen pro- and anti-apoptotic drugs, and to examine Apaf-1-dependent cellular pathways.
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Affiliation(s)
- Elaheh Sadat Hosseini
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
- Department of Nanobiotechnology, Pharmacology and Therapeutics, School of Medicine, NUI, Galway, Ireland
- Department of Nanobiotechnology, Museum National d'Histoire Naturelle, Laboratoire Structure et Instabilité des Génomes - INSERM U1154 - CNRS 7196; Laboratoire de Biophysique, Sorbonne Universités, Paris, F-75231, France
| | - Maryam Nikkhah
- Department of Nanobiotechnology, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Amir Ali Hamidieh
- Pediatric Cell Therapy Research Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Howard O. Fearnhead
- Department of Nanobiotechnology, Pharmacology and Therapeutics, School of Medicine, NUI, Galway, Ireland
| | - Jean-Paul Concordet
- Department of Nanobiotechnology, Museum National d'Histoire Naturelle, Laboratoire Structure et Instabilité des Génomes - INSERM U1154 - CNRS 7196; Laboratoire de Biophysique, Sorbonne Universités, Paris, F-75231, France
| | - Saman Hosseinkhani
- Department of Biochemistry, Faculty of Biological Sciences, Tarbiat Modares University, Tehran 14115-175, Iran
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18
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Vocelle D, Chan C, Walton SP. Endocytosis Controls siRNA Efficiency: Implications for siRNA Delivery Vehicle Design and Cell-Specific Targeting. Nucleic Acid Ther 2020; 30:22-32. [PMID: 31718426 PMCID: PMC6987736 DOI: 10.1089/nat.2019.0804] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 10/10/2019] [Indexed: 12/19/2022] Open
Abstract
While small interfering RNAs (siRNAs) are commonly used for laboratory studies, development of siRNA therapeutics has been slower than expected, due, in part, to a still limited understanding of the endocytosis and intracellular trafficking of siRNA-containing complexes. With the recent characterization of multiple clathrin-/caveolin-independent endocytic pathways, that is, those mediated by Graf1, Arf6, and flotillin, it has become clear that the endocytic mechanism influences subsequent intracellular processing of the internalized cargo. To explore siRNA delivery in light of these findings, we developed a novel assay that differentiates uptake by each of the endocytic pathways and can be used to determine whether endocytosis by a pathway leads to the initiation of RNA interference (RNAi). Using Lipofectamine 2000 (LF2K), we determined the endocytosis pathway leading to active silencing (whether by clathrin, caveolin, Arf6, Graf1, flotillin, or macropinocytosis) across multiple cell types (HeLa, H1299, HEK293, and HepG2). We showed that LF2K is internalized by Graf1-, Arf6-, or flotillin-mediated endocytosis for the initiation of RNAi, depending on cell type. In addition, we found that a portion of siRNA-containing complexes is internalized by pathways that do not lead to initiation of silencing. Inhibition of these pathways enhanced intracellular levels of siRNAs with concomitant enhancement of silencing.
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Affiliation(s)
- Daniel Vocelle
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan
| | - Christina Chan
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan
| | - S. Patrick Walton
- Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, Michigan
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19
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Moreira IB, Pinto F, Gomes C, Campos D, Reis CA. Impact of Truncated O-glycans in Gastric-Cancer-Associated CD44v9 Detection. Cells 2020; 9:cells9020264. [PMID: 31973075 PMCID: PMC7072479 DOI: 10.3390/cells9020264] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 01/16/2020] [Accepted: 01/17/2020] [Indexed: 02/06/2023] Open
Abstract
CD44 variant isoforms are often upregulated in cancer and associated with increased aggressive tumor phenotypes. The CD44v9 is one of the major protein splice variant isoforms expressed in human gastrointestinal cancer cells. Immunodetection of CD44 isoforms like CD44v9 in tumor tissue is almost exclusively performed by using specific monoclonal antibodies. However, the structural variability conferred by both the alternative splicing and CD44 protein glycosylation is disregarded. In the present work, we have evaluated the role of O-glycosylation using glycoengineered gastric cancer models in the detection of CD44v9 by monoclonal antibodies. We demonstrated, using different technical approaches, that the presence of immature O-glycan structures, such as Tn and STn, enhance CD44v9 protein detection. These findings can have significant implications in clinical applications mainly at the detection and targeting of this cancer-related CD44v9 isoform and highlight the utmost importance of considering glycan structures in cancer biomarker detection and in therapy targeting.
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Affiliation(s)
- Inês B. Moreira
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Filipe Pinto
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Catarina Gomes
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
| | - Diana Campos
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
- Correspondence: (D.C.); (C.A.R.)
| | - Celso A. Reis
- I3S–Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal; (I.B.M.); (F.P.); (C.G.)
- IPATIMUP–Institute of Molecular Pathology and Immunology, University of Porto, 4200-135 Porto, Portugal
- Faculty of Medicine, University of Porto, 4200-319 Porto, Portugal
- Instituto de Ciências Biomédicas Abel Salazar, University of Porto, 4050-313 Porto, Portugal
- Correspondence: (D.C.); (C.A.R.)
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20
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Mitigating Clonal Variation in Recombinant Mammalian Cell Lines. Trends Biotechnol 2019; 37:931-942. [DOI: 10.1016/j.tibtech.2019.02.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Revised: 02/14/2019] [Accepted: 02/19/2019] [Indexed: 12/27/2022]
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21
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Kirkley KS, Popichak KA, Hammond SL, Davies C, Hunt L, Tjalkens RB. Genetic suppression of IKK2/NF-κB in astrocytes inhibits neuroinflammation and reduces neuronal loss in the MPTP-Probenecid model of Parkinson's disease. Neurobiol Dis 2019; 127:193-209. [PMID: 30818064 PMCID: PMC6588478 DOI: 10.1016/j.nbd.2019.02.020] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 12/20/2018] [Accepted: 02/22/2019] [Indexed: 12/13/2022] Open
Abstract
Neuroinflammatory activation of glia is considered a pathological hallmark of Parkinson's disease (PD) and is seen in both human PD patients and in animal models of PD; however, the relative contributions of these cell types, especially astrocytes, to the progression of disease is not fully understood. The transcription factor, nuclear factor kappa B (NFκB), is an important regulator of inflammatory gene expression in glia and is activated by multiple cellular stress signals through the kinase complex, IKK2. We sought to determine the role of NFκB in modulating inflammatory activation of astrocytes in a model of PD by generating a conditional knockout mouse (hGfapcre/Ikbk2F/F) in which IKK2 is specifically deleted in astrocytes. Measurements of IKK2 revealed a 70% deletion rate of IKK2 within astrocytes, as compared to littermate controls (Ikbk2F/F). Use of this mouse in a subacute, progressive model of PD through exposure to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine and probenecid (MPTPp) revealed significant protection in exposed mice to direct and progressive loss of dopaminergic neurons in the substantia nigra (SN). hGfapcre/Ikbk2F/F mice were also protected against MPTPp-induced loss in motor activity, loss of striatal proteins, and genomic alterations in nigral NFκB gene expression, but were not protected from loss of striatal catecholamines. Neuroprotection in hGfapcre/Ikbk2F/F mice was associated with inhibition of MPTPp-induced astrocytic expression of inflammatory genes and protection against nitrosative stress and apoptosis in neurons. These data indicate that deletion of IKK2 within astrocytes is neuroprotective in the MPTPp model of PD and suggests that reactive astrocytes directly contribute the potentiation of dopaminergic pathology.
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Affiliation(s)
- Kelly S Kirkley
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Katriana A Popichak
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Sean L Hammond
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Cecilia Davies
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Lindsay Hunt
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523
| | - Ronald B Tjalkens
- Department of Environmental and Radiological Health Sciences, Colorado State University, Fort Collins, CO, USA 80523; Program in Molecular, Cellular and Integrative Neuroscience, Colorado State University, Fort Collins, CO, USA 80523.
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22
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Pristovšek N, Nallapareddy S, Grav LM, Hefzi H, Lewis NE, Rugbjerg P, Hansen HG, Lee GM, Andersen MR, Kildegaard HF. Systematic Evaluation of Site-Specific Recombinant Gene Expression for Programmable Mammalian Cell Engineering. ACS Synth Biol 2019; 8:758-774. [PMID: 30807689 DOI: 10.1021/acssynbio.8b00453] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Many branches of biology depend on stable and predictable recombinant gene expression, which has been achieved in recent years through targeted integration of the recombinant gene into defined integration sites. However, transcriptional levels of recombinant genes in characterized integration sites are controlled by multiple components of the integrated expression cassette. Lack of readily available tools has inhibited meaningful experimental investigation of the interplay between the integration site and the expression cassette components. Here we show in a systematic manner how multiple components contribute to final net expression of recombinant genes in a characterized integration site. We develop a CRISPR/Cas9-based toolbox for construction of mammalian cell lines with targeted integration of a landing pad, containing a recombinant gene under defined 5' proximal regulatory elements. Generated site-specific recombinant cell lines can be used in a streamlined recombinase-mediated cassette exchange for fast screening of different expression cassettes. Using the developed toolbox, we show that different 5' proximal regulatory elements generate distinct and robust recombinant gene expression patterns in defined integration sites of CHO cells with a wide range of transcriptional outputs. This approach facilitates the generation of user-defined and product-specific gene expression patterns for programmable mammalian cell engineering.
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Affiliation(s)
- Nuša Pristovšek
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Saranya Nallapareddy
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Lise Marie Grav
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Hooman Hefzi
- Departments of Pediatrics and Bioengineering, 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
- Departments of Pediatrics and Bioengineering, 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
| | - Peter Rugbjerg
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Henning Gram Hansen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
| | - Gyun Min Lee
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
- Department of Biological Sciences, KAIST, 291 Daehak-ro,
Yuseong-gu, Daejeon 305-701, Republic of Korea
| | - Mikael Rørdam Andersen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, Building 223, 2800 Kgs. Lyngby, Denmark
| | - Helene Faustrup Kildegaard
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kemitorvet, Building 220, 2800 Kgs. Lyngby, Denmark
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23
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Jazayeri SH, Amiri-Yekta A, Bahrami S, Gourabi H, Sanati MH, Khorramizadeh MR. Vector and Cell Line Engineering Technologies Toward Recombinant Protein Expression in Mammalian Cell Lines. Appl Biochem Biotechnol 2018; 185:986-1003. [PMID: 29396733 DOI: 10.1007/s12010-017-2689-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 12/29/2017] [Indexed: 11/26/2022]
Abstract
The rapid growth of global biopharmaceutical market in the recent years has been a good indication of its significance in biotechnology industry. During a long period of time in recombinant protein production from 1980s, optimizations in both upstream and downstream processes were launched. In this regard, one of the most promising strategies is expression vector engineering technology based on incorporation of DNA opening elements found in the chromatin border regions of vectors as well as targeting gene integration. Along with these approaches, cell line engineering has revealed convenient outcomes in isolating high-producing clones. According to the fact that more than 50% of the approved therapeutic proteins is being manufactured in mammalian cell lines, in this review, we focus on several approaches and developments in vector and cell line engineering technologies in mammalian cell culture.
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Affiliation(s)
- Seyedeh Hoda Jazayeri
- Department of Medical Biotechnology, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
- Department of Genetics, Reproductive Biomedicine Research Center, ACECR, Royan Institute for Reproductive Biomedicine, P.O. Box: 14155-6343, Tehran, Iran
| | - Amir Amiri-Yekta
- Department of Genetics, Reproductive Biomedicine Research Center, ACECR, Royan Institute for Reproductive Biomedicine, P.O. Box: 14155-6343, Tehran, Iran
| | - Salahadin Bahrami
- Department of Genetics, Reproductive Biomedicine Research Center, ACECR, Royan Institute for Reproductive Biomedicine, P.O. Box: 14155-6343, Tehran, Iran
| | - Hamid Gourabi
- Department of Genetics, Reproductive Biomedicine Research Center, ACECR, Royan Institute for Reproductive Biomedicine, P.O. Box: 14155-6343, Tehran, Iran
| | - Mohammad Hossein Sanati
- Department of Genetics, Reproductive Biomedicine Research Center, ACECR, Royan Institute for Reproductive Biomedicine, P.O. Box: 14155-6343, Tehran, Iran.
- Department of Medical Genetics, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran.
| | - Mohammad Reza Khorramizadeh
- Biosensor Research Center, Endocrinology and Metabolism Molecular-Cellular Sciences Institute, Tehran University of Medical Sciences, P.O. Box: 1411413137, Tehran, Iran.
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Söllradl T, Chabot K, Fröhlich U, Canva M, Charette PG, Grandbois M. Monitoring individual cell-signaling activity using combined metal-clad waveguide and surface-enhanced fluorescence imaging. Analyst 2018; 143:5559-5567. [DOI: 10.1039/c8an00911b] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Validation of a combined metal-clad waveguide and surface enhanced fluorescence imaging platform for live cell imaging.
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Affiliation(s)
- Thomas Söllradl
- Laboratoire Nanotechnologies Nanosystèmes (LN2) – CNRS UMI-3463
- Université de Sherbrooke
- Canada
- Institut Interdisciplinaire d'Innovation Technologique (3IT)
- Université de Sherbrooke
| | - Kevin Chabot
- Laboratoire Nanotechnologies Nanosystèmes (LN2) – CNRS UMI-3463
- Université de Sherbrooke
- Canada
- Institut Interdisciplinaire d'Innovation Technologique (3IT)
- Université de Sherbrooke
| | - Ulrike Fröhlich
- Département de Pharmacologie et Physiologie
- Université de Sherbrooke
- Canada
| | - Michael Canva
- Laboratoire Nanotechnologies Nanosystèmes (LN2) – CNRS UMI-3463
- Université de Sherbrooke
- Canada
- Institut Interdisciplinaire d'Innovation Technologique (3IT)
- Université de Sherbrooke
| | - Paul G. Charette
- Laboratoire Nanotechnologies Nanosystèmes (LN2) – CNRS UMI-3463
- Université de Sherbrooke
- Canada
- Institut Interdisciplinaire d'Innovation Technologique (3IT)
- Université de Sherbrooke
| | - Michel Grandbois
- Laboratoire Nanotechnologies Nanosystèmes (LN2) – CNRS UMI-3463
- Université de Sherbrooke
- Canada
- Département de Pharmacologie et Physiologie
- Université de Sherbrooke
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25
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Site-specific chromosomal gene insertion: Flp recombinase versus Cas9 nuclease. Sci Rep 2017; 7:17771. [PMID: 29259215 PMCID: PMC5736728 DOI: 10.1038/s41598-017-17651-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Accepted: 11/24/2017] [Indexed: 12/16/2022] Open
Abstract
Site-specific recombination systems like those based on the Flp recombinase proved themselves as efficient tools for cell line engineering. The recent emergence of designer nucleases, especially RNA guided endonucleases like Cas9, has considerably broadened the available toolbox for applications like targeted transgene insertions. Here we established a recombinase-mediated cassette exchange (RMCE) protocol for the fast and effective, drug-free isolation of recombinant cells. Distinct fluorescent protein patterns identified the recombination status of individual cells. In derivatives of a CHO master cell line the expression of the introduced transgene of interest could be dramatically increased almost 20-fold by subsequent deletion of the fluorescent protein gene that provided the initial isolation principle. The same master cell line was employed in a comparative analysis using CRISPR/Cas9 for transgene integration in identical loci. Even though the overall targeting efficacy was comparable, multi-loci targeting was considerably more effective for Cas9-mediated transgene insertion when compared to RMCE. While Cas9 is inherently more flexible, our results also alert to the risk of aberrant recombination events around the cut site. Together, this study points at the individual strengths in performance of both systems and provides guidance for their appropriate use.
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Vidigal J, Fernandes B, Dias MM, Patrone M, Roldão A, Carrondo MJT, Alves PM, Teixeira AP. RMCE-based insect cell platform to produce membrane proteins captured on HIV-1 Gag virus-like particles. Appl Microbiol Biotechnol 2017; 102:655-666. [DOI: 10.1007/s00253-017-8628-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/03/2017] [Accepted: 11/05/2017] [Indexed: 12/20/2022]
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27
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Ebadat S, Ahmadi S, Ahmadi M, Nematpour F, Barkhordari F, Mahdian R, Davami F, Mahboudi F. Evaluating the efficiency of CHEF and CMV promoter with IRES and Furin/2A linker sequences for monoclonal antibody expression in CHO cells. PLoS One 2017; 12:e0185967. [PMID: 29023479 PMCID: PMC5638317 DOI: 10.1371/journal.pone.0185967] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 09/24/2017] [Indexed: 11/19/2022] Open
Abstract
In recent years, monoclonal antibodies (mAbs) have been developed as powerful therapeutic and diagnostic agents and Chinese hamster ovary (CHO) cells have emerged as the dominant host for the recombinant expression of these proteins. A critical step in recombinant expression is the utilization of strong promoters, such as the Chinese Hamster Elongation Factor-1α (CHEF-1) promoter. To compare the strengths of CHEF with cytomegalovirus (CMV) promoter for mAb expression in CHO cells, four bicistronic vectors bearing either internal ribosome entry site (IRES) or Furin/2A (F2A) sequences were designed. The efficiency of these promoters was evaluated by measuring level of expressed antibody in stable cell pools. Our results indicated that CHEF promoter-based expression of mAbs was 2.5 fold higher than CMV-based expression in F2A-mediated vectors. However, this difference was less significant in IRES-mediated mAb expressing cells. Studying the stability of the F2A expression system in the course of 18 weeks, we observed that the cells having CHEF promoter maintained their antibody expression at higher level than those transfected with CMV promoter. Further analyses showed that both IRES-mediated vectors, expressed mAbs with correct size, whereas in antibodies expressed via F2A system heterogeneity of light chains were detected due to incomplete furin cleavage. Our findings indicated that the CHEF promoter is a viable alternative to CMV promoter-based expression in F2A-mediated vectors by providing both higher expression and level of stability.
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Affiliation(s)
- Saeedeh Ebadat
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Samira Ahmadi
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Maryam Ahmadi
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
- Medical Biotechnology Department, Semnan University of Medical Sciences, Semnan, Iran
| | - Fatemeh Nematpour
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | | | - Reza Mahdian
- Molecular Medicine Department, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
| | - Fatemeh Davami
- Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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Lengthening of high-yield production levels of monoclonal antibody-producing Chinese hamster ovary cells by downregulation of breast cancer 1. J Biosci Bioeng 2017; 123:382-389. [DOI: 10.1016/j.jbiosc.2016.09.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 11/19/2022]
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29
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Poitevin Y, Pontini G, Fischer N, Kosco-Vilbois M, Elson G. Magnetic sorting of membrane associated IgG for phenotype-based selection of stable antibody producing cells. J Immunol Methods 2017; 444:1-6. [PMID: 28189705 DOI: 10.1016/j.jim.2017.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Revised: 02/07/2017] [Accepted: 02/07/2017] [Indexed: 12/11/2022]
Abstract
To establish a simple and widely accessible technique for rapidly selecting high producing Chinese hamster ovary (CHO) cells engineered to express a monoclonal antibody (mAb), we have exploited the transient display of recombinant protein on their cell surface. In combination with magnetic bead-based methods, we demonstrate the ability to select for cells of high productivity in the absence of any metabolic-based selection method. This technique is sufficient to obtain genetically stable engineered CHO cells via a single step of cell subcloning and yields sought-after stable, high IgG producing clonal cell lines. This technique may also be applied to other types of cells as well as polyclonal Ab cell pools.
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Affiliation(s)
- Y Poitevin
- Novimmune SA, 14 chemin des Aulx 1228 Plan-Les-Ouates, Switzerland.
| | - G Pontini
- Novimmune SA, 14 chemin des Aulx 1228 Plan-Les-Ouates, Switzerland
| | - N Fischer
- Novimmune SA, 14 chemin des Aulx 1228 Plan-Les-Ouates, Switzerland
| | - M Kosco-Vilbois
- Novimmune SA, 14 chemin des Aulx 1228 Plan-Les-Ouates, Switzerland
| | - G Elson
- Novimmune SA, 14 chemin des Aulx 1228 Plan-Les-Ouates, Switzerland
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Hoenicka H, Lehnhardt D, Nunna S, Reinhardt R, Jeltsch A, Briones V, Fladung M. Level of tissue differentiation influences the activation of a heat-inducible flower-specific system for genetic containment in poplar (Populus tremula L.). PLANT CELL REPORTS 2016; 35:369-84. [PMID: 26521210 DOI: 10.1007/s00299-015-1890-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 09/04/2015] [Accepted: 10/16/2015] [Indexed: 05/20/2023]
Abstract
Differentiation level but not transgene copy number influenced activation of a gene containment system in poplar. Heat treatments promoted CRE gene body methylation. The flower-specific transgene deletion was confirmed. Gene flow between genetic modified trees and their wild relatives is still motive of concern. Therefore, approaches for gene containment are required. In this study, we designed a novel strategy for achieving an inducible and flower-specific transgene removal from poplar trees but still expressing the transgene in the plant body. Hence, pollen carrying transgenes could be used for breeding purposes under controlled conditions in a first phase, and in the second phase genetic modified poplars developing transgene-free pollen grains could be released. This approach is based on the recombination systems CRE/loxP and FLP/frt. Both gene constructs contained a heat-inducible CRE/loxP-based spacer sequence for in vivo assembling of the flower-specific FLP/frt system. This allowed inducible activation of gene containment. The FLP/frt system was under the regulation of a flower-specific promoter, either CGPDHC or PTD. Our results confirmed complete CRE/loxP-based in vivo assembling of the flower-specific transgene excision system after heat treatment in all cells for up to 30 % of regenerants derived from undifferentiated tissue cultures. Degradation of HSP::CRE/loxP spacer after recombination but also persistence as extrachromosomal DNA circles were detected in sub-lines obtained after heat treatments. Furthermore, heat treatment promoted methylation of the CRE gene body. A lower methylation level was detected at CpG sites in transgenic sub-lines showing complete CRE/loxP recombination and persistence of CRE/loxP spacer, compared to sub-lines with incomplete recombination. However, our results suggest that low methylation might be necessary but not sufficient for recombination. The flower-specific FLP/frt-based transgene deletion was confirmed in 6.3 % of flowers.
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Affiliation(s)
- Hans Hoenicka
- Thünen-Institute of Forest Genetics, 22927, Grosshansdorf, Germany.
| | - Denise Lehnhardt
- Thünen-Institute of Forest Genetics, 22927, Grosshansdorf, Germany
| | - Suneetha Nunna
- Institute of Biochemistry, University of Stuttgart, 70569, Stuttgart, Germany
| | | | - Albert Jeltsch
- Institute of Biochemistry, University of Stuttgart, 70569, Stuttgart, Germany
| | | | - Matthias Fladung
- Thünen-Institute of Forest Genetics, 22927, Grosshansdorf, Germany.
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31
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Geburek F, Mundle K, Conrad S, Hellige M, Walliser U, van Schie HTM, van Weeren R, Skutella T, Stadler PM. Tracking of autologous adipose tissue-derived mesenchymal stromal cells with in vivo magnetic resonance imaging and histology after intralesional treatment of artificial equine tendon lesions--a pilot study. Stem Cell Res Ther 2016; 7:21. [PMID: 26830812 PMCID: PMC4736260 DOI: 10.1186/s13287-016-0281-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 12/16/2015] [Accepted: 01/14/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Adipose tissue-derived mesenchymal stromal cells (AT-MSCs) are frequently used to treat equine tendinopathies. Up to now, knowledge about the fate of autologous AT-MSCs after intralesional injection into equine superficial digital flexor tendons (SDFTs) is very limited. The purpose of this study was to monitor the presence of intralesionally injected autologous AT-MSCs labelled with superparamagnetic iron oxide (SPIO) nanoparticles and green fluorescent protein (GFP) over a staggered period of 3 to 9 weeks with standing magnetic resonance imaging (MRI) and histology. METHODS Four adult warmblood horses received a unilateral injection of 10 × 10(6) autologous AT-MSCs into surgically created front-limb SDFT lesions. Administered AT-MSCs expressed lentivirally transduced reporter genes for GFP and were co-labelled with SPIO particles in three horses. The presence of AT-MSCs in SDFTs was evaluated by repeated examinations with standing low-field MRI in two horses and post-mortem in all horses with Prussian blue staining, fluorescence microscopy and with immunofluorescence and immunohistochemistry using anti-GFP antibodies at 3, 5, 7 and 9 weeks after treatment. RESULTS AT-MSCs labelled with SPIO particles were detectable in treated SDFTs during each MRI in T2*- and T1-weighted sequences until the end of the observation period. Post-mortem examinations revealed that all treated tendons contained high numbers of SPIO- and GFP-labelled cells. CONCLUSIONS Standing low-field MRI has the potential to track SPIO-labelled AT-MSCs successfully. Histology, fluorescence microscopy, immunofluorescence and immunohistochemistry are efficient tools to detect labelled AT-MSCs after intralesional injection into surgically created equine SDFT lesions. Intralesional injection of 10 × 10(6) AT-MSCs leads to the presence of high numbers of AT-MSCs in and around surgically created tendon lesions for up to 9 weeks. Integration of injected AT-MSCs into healing tendon tissue is an essential pathway after intralesional administration. Injection techniques have to be chosen deliberately to avoid reflux of the cell substrate injected. In vivo low-field MRI may be used as a non-invasive tool to monitor homing and engraftment of AT-MSCs in horses with tendinopathy of the SDFT.
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Affiliation(s)
- Florian Geburek
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.
| | - Kathrin Mundle
- Pferdeklink Kirchheim, Nürtinger Straße 200, 73230, Kirchheim unter Teck, Germany.
| | | | - Maren Hellige
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.
| | - Ulrich Walliser
- Pferdeklink Kirchheim, Nürtinger Straße 200, 73230, Kirchheim unter Teck, Germany.
| | - Hans T M van Schie
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584, CM, Utrecht, The Netherlands.
| | - René van Weeren
- Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 112, 3584, CM, Utrecht, The Netherlands.
| | - Thomas Skutella
- Institute for Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, 69120, Heidelberg, Germany.
| | - Peter M Stadler
- Clinic for Horses, University of Veterinary Medicine Hannover, Foundation, Bünteweg 9, 30559, Hannover, Germany.
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Moritz B, Becker PB, Göpfert U. CMV promoter mutants with a reduced propensity to productivity loss in CHO cells. Sci Rep 2015; 5:16952. [PMID: 26581326 PMCID: PMC4652263 DOI: 10.1038/srep16952] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/22/2015] [Indexed: 11/09/2022] Open
Abstract
The major immediate-early promoter and enhancer of the human cytomegalovirus (hCMV-MIE) is one of the most potent DNA elements driving recombinant gene expression in mammalian cells. Therefore, it is widely employed not only in research but also in large-scale industrial applications, e.g. for the production of therapeutic antibodies in Chinese hamster ovary cells (CHO). As we have reported previously, multi-site methylation of hCMV-MIE is linked to productivity loss in permanently transfected CHO cells lines. In particular, the cytosine located 179 bp upstream of the transcription start site (C-179) is frequently methylated. Therefore, our objective was to study whether mutation of C-179 and other cytosines within hCMV-MIE might lessen the instability of transgene expression. We discovered that the single mutation of C-179 to G can significantly stabilise the production of recombinant protein under control of hCMV-MIE in permanently transfected CHO cells.
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Affiliation(s)
- Benjamin Moritz
- Roche Pharmaceutical Research and Early Development, Large Molecule Research, Roche Innovation Center Penzberg, Germany
| | - Peter B Becker
- Biomedical Center and Center for Integrated Protein Science Munich, Ludwig Maximilian University, Munich, Germany
| | - Ulrich Göpfert
- Roche Pharmaceutical Research and Early Development, Large Molecule Research, Roche Innovation Center Penzberg, Germany
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Krinner S, Heitzer A, Asbach B, Wagner R. Interplay of Promoter Usage and Intragenic CpG Content: Impact on GFP Reporter Gene Expression. Hum Gene Ther 2015; 26:826-40. [PMID: 26414116 DOI: 10.1089/hum.2015.075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Successful therapeutic protein production in vitro and in vivo requires efficient and long-term transgene expression supported by optimized vector and transgene cis-regulatory sequence elements. This study provides a comparative analysis of CpG-rich, highly expressed, versus CpG-depleted, poorly expressed green fluorescent protein (GFP) reporter transgenes, transcribed by various promoters in two different cell systems. Long-term GFP expression from a defined locus in stable Chinese hamster ovary cells was clearly influenced by the combination of transgene CpG content and promoter usage, as shown by differential silencing effects on selection pressure removal among the cytomegalovirus (CMV) promoter and elongation factor (EF)-1α promoter. Whereas a high intragenic CpG content promoted local DNA methylation, CpG depletion rather accelerated transgene loss and increased the local chromatin density. On lentiviral transfer of various expression modules into epigenetically sensitive P19 embryonic pluripotent carcinoma cells, CMV promoter usage led to rapid gene silencing irrespective of the intragenic CpG content. In contrast, EF-1α promoter-controlled constructs showed delayed silencing activity and high-level transgene expression, in particular when the CpG-rich GFP reporter was used. Notably, GFP silencing in P19 cells could be prevented completely by the bidirectional, dual divergently transcribed A2UCOE (ubiquitously acting chromatin-opening element derived from the human HNRPA2B1-CBX3 locus) promoter. Because the level of GFP expression by the A2UCOE promoter was entirely unaffected by the intragenic CpG level, we suggest that A2UCOE can overcome chromatin compaction resulting from intragenic CpG depletion due to its ascribed chromatin-opening abilities. Our analyses provide insights into the interplay of the intragenic CpG content with promoter sequences and regulatory sequence elements, thus contributing toward the design of therapeutic transgene expression cassettes for future gene therapy applications.
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Affiliation(s)
- Simone Krinner
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology and Gene Therapy Unit, University of Regensburg , Regensburg, Germany
| | - Asli Heitzer
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology and Gene Therapy Unit, University of Regensburg , Regensburg, Germany
| | - Benedikt Asbach
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology and Gene Therapy Unit, University of Regensburg , Regensburg, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, Molecular Microbiology and Gene Therapy Unit, University of Regensburg , Regensburg, Germany
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Büssow K. Stable mammalian producer cell lines for structural biology. Curr Opin Struct Biol 2015; 32:81-90. [DOI: 10.1016/j.sbi.2015.03.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 02/11/2015] [Accepted: 03/03/2015] [Indexed: 11/28/2022]
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Mariati, Yeo JHM, Koh EYC, Ho SCL, Yang Y. Insertion of core CpG island element into human CMV promoter for enhancing recombinant protein expression stability in CHO cells. Biotechnol Prog 2014; 30:523-34. [DOI: 10.1002/btpr.1919] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Revised: 04/02/2014] [Indexed: 01/17/2023]
Affiliation(s)
- Mariati
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Jessna H. M. Yeo
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Esther Y. C. Koh
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Steven C. L. Ho
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
| | - Yuansheng Yang
- Bioprocessing Technology Inst., Agency for Science, Technology and Research (A*STAR); Singapore 138668 Singapore
- School of Chemical and Biomedical Engineering, Nanyang Technological University; Singapore 637459 Singapore
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36
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Marker-free plasmids for biotechnological applications – implications and perspectives. Trends Biotechnol 2013; 31:539-47. [DOI: 10.1016/j.tibtech.2013.06.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/03/2013] [Accepted: 06/03/2013] [Indexed: 11/22/2022]
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Paredes V, Park JS, Jeong Y, Yoon J, Baek K. Unstable expression of recombinant antibody during long-term culture of CHO cells is accompanied by histone H3 hypoacetylation. Biotechnol Lett 2013; 35:987-93. [PMID: 23468139 DOI: 10.1007/s10529-013-1168-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2012] [Accepted: 02/18/2013] [Indexed: 10/27/2022]
Abstract
The gradual loss of recombinant protein expression in CHO cell lines during prolonged subculture is a common issue, referred to as instability, which seriously affects the industrial production processes of therapeutic proteins. Loss of recombinant gene copies, due to the genetic instability of CHO cells, and epigenetic silencing of transgene sequences, are the main reported causes of production instability. To increase our understanding on the molecular mechanisms inherent to CHO cells involved in production instability, we explored the molecular features of stable and unstable antibody producing cell lines obtained without gene amplification, to exclude the genetic instability induced by the gene amplification process. The instability of recombinant antibody production during long-term culture was caused by a 48-53% decrease in recombinant mRNA levels without significant loss of recombinant gene copies, but accompanied by a ~45% decrease in histone H3 acetylation (H3ac). Thus, our results suggest a critical role of H3ac in the stability of recombinant protein production.
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Affiliation(s)
- Verenice Paredes
- Department of Genetic Engineering and Graduate School of Biotechnology, Kyung Hee University, Yongin-si, Republic of Korea.
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38
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Recombinase-mediated cassette exchange (RMCE) — A rapidly-expanding toolbox for targeted genomic modifications. Gene 2013. [DOI: 10.1016/j.gene.2012.11.016] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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39
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Klug JR, Mathur BN, Kash TL, Wang HD, Matthews RT, Robison AJ, Anderson ME, Deutch AY, Lovinger DM, Colbran RJ, Winder DG. Genetic inhibition of CaMKII in dorsal striatal medium spiny neurons reduces functional excitatory synapses and enhances intrinsic excitability. PLoS One 2012; 7:e45323. [PMID: 23028932 PMCID: PMC3448631 DOI: 10.1371/journal.pone.0045323] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2012] [Accepted: 08/15/2012] [Indexed: 11/18/2022] Open
Abstract
Ca2+/calmodulin-dependent protein kinase II (CaMKII) is abundant in striatal medium spiny neurons (MSNs). CaMKII is dynamically regulated by changes in dopamine signaling, as occurs in Parkinson's disease as well as addiction. Although CaMKII has been extensively studied in the hippocampus where it regulates excitatory synaptic transmission, relatively little is known about how it modulates neuronal function in the striatum. Therefore, we examined the impact of selectively overexpressing an EGFP-fused CaMKII inhibitory peptide (EAC3I) in striatal medium spiny neurons (MSNs) using a novel transgenic mouse model. EAC3I-expressing cells exhibited markedly decreased excitatory transmission, indicated by a decrease in the frequency of spontaneous excitatory postsynaptic currents (sEPSCs). This decrease was not accompanied by changes in the probability of release, levels of glutamate at the synapse, or changes in dendritic spine density. CaMKII regulation of the AMPA receptor subunit GluA1 is a major means by which the kinase regulates neuronal function in the hippocampus. We found that the decrease in striatal excitatory transmission seen in the EAC3I mice is mimicked by deletion of GluA1. Further, while CaMKII inhibition decreased excitatory transmission onto MSNs, it increased their intrinsic excitability. These data suggest that CaMKII plays a critical role in setting the excitability rheostat of striatal MSNs by coordinating excitatory synaptic drive and the resulting depolarization response.
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Affiliation(s)
- Jason R. Klug
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Brian N. Mathur
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Thomas L. Kash
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Hui-Dong Wang
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - Robert T. Matthews
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - A. J. Robison
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Mark E. Anderson
- Departments of Internal Medicine and Molecular Physiology and Biophysics, University of Iowa, Iowa City, Iowa, United States of America
| | - Ariel Y. Deutch
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Department of Psychiatry, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, United States of America
| | - David M. Lovinger
- Laboratory for Integrative Neuroscience, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland, United States of America
| | - Roger J. Colbran
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
| | - Danny G. Winder
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- Center for Molecular Neuroscience, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- J.F. Kennedy Center for Research on Human Development, Vanderbilt University School of Medicine, Nashville, Tennessee, United States of America
- * E-mail:
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Gordeev AA, Chetverina HV, Chetverin AB. Planar arrangement of eukaryotic cells in merged hydrogels combines the advantages of 3-D and 2-D cultures. Biotechniques 2012; 52:325-31. [DOI: 10.2144/000113861] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2011] [Accepted: 04/04/2012] [Indexed: 11/23/2022] Open
Abstract
We report an unordered 2-D array of eukaryotic cells completely embedded in a 3-D matrix. Every cell is located at the same distance from the gel surface, which ensures uniformity of growth conditions and ease of observation characteristic of a 2-D culture. Each cell is firmly immobilized, and each has a unique address in the array. The cells can be rapidly screened, individually monitored during extended time periods, and cultured with the formation of spheroid microcolonies characteristic of a 3-D culture. Individual microcolonies can be extracted from the gel and further propagated, thus enabling isolation of pure cell clones from rather dense cell populations and rapid drug-free generation of stable cell lines.
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Affiliation(s)
- Alexander A. Gordeev
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Helena V. Chetverina
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Alexander B. Chetverin
- Institute of Protein Research of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
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41
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Kacherovsky N, Harkey MA, Blau CA, Giachelli CM, Pun SH. Combination of Sleeping Beauty transposition and chemically induced dimerization selection for robust production of engineered cells. Nucleic Acids Res 2012; 40:e85. [PMID: 22402491 PMCID: PMC3367214 DOI: 10.1093/nar/gks213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The main methods for producing genetically engineered cells use viral vectors for which safety issues and manufacturing costs remain a concern. In addition, selection of desired cells typically relies on the use of cytotoxic drugs with long culture times. Here, we introduce an efficient non-viral approach combining the Sleeping Beauty (SB) Transposon System with selective proliferation of engineered cells by chemically induced dimerization (CID) of growth factor receptors. Minicircles carrying a SB transposon cassette containing a reporter transgene and a gene for the F36VFGFR1 fusion protein were delivered to the hematopoietic cell line Ba/F3. Stably-transduced Ba/F3 cell populations with >98% purity were obtained within 1 week using this positive selection strategy. Copy number analysis by quantitative PCR (qPCR) revealed that CID-selected cells contain on average higher copy numbers of transgenes than flow cytometry-selected cells, demonstrating selective advantage for cells with multiple transposon insertions. A diverse population of cells is present both before and after culture in CID media, although site-specific qPCR of transposon junctions show that population diversity is significantly reduced after selection due to preferential expansion of clones with multiple integration events. This non-viral, positive selection approach is an attractive alternative for producing engineered cells.
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Affiliation(s)
- Nataly Kacherovsky
- Department of Bioengineering, University of Washington, Seattle, WA 98195, USA
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42
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Yin Z, Kong QR, Zhao ZP, Wu ML, Mu YS, Hu K, Liu ZH. Position effect variegation and epigenetic modification of a transgene in a pig model. GENETICS AND MOLECULAR RESEARCH 2012; 11:355-69. [PMID: 22370938 DOI: 10.4238/2012.february.16.1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Sequences proximal to transgene integration sites are able to regulate transgene expression, resulting in complex position effect variegation. Position effect variegation can cause differences in epigenetic modifications, such as DNA methylation and histone acetylation. However, it is not known which factor, position effect or epigenetic modification, plays a more important role in the regulation of transgene expression. We analyzed transgene expression patterns and epigenetic modifications of transgenic pigs expressing green fluorescent protein, driven by the cytomegalovirus (CMV) promoter. DNA hypermethylation and loss of acetylation of specific histone H3 and H4 lysines, except H4K16 acetylation in the CMV promoter, were consistent with a low level of transgene expression. Moreover, the degree of DNA methylation and histone H3/H4 acetylation in the promoter region depended on the integration site; consequently, position effect variegation caused variations in epigenetic modifications. The transgenic pig fibroblast cell lines were treated with DNA methyltransferase inhibitor 5-Aza-2'-deoxycytidine and/or histone deacetylase inhibitor trichostatin A. Transgene expression was promoted by reversing the DNA hypermethylation and histone hypoacetylation status. The differences in DNA methylation and histone acetylation in the CMV promoter region in these cell lines were not significant; however, significant differences in transgene expression were detected, demonstrating that variegation of transgene expression is affected by the integration site. We conclude that in this pig model, position effect variegation affects transgene expression.
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Affiliation(s)
- Z Yin
- College of Life Science, Northeast Agricultural University of China, Harbin, China
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43
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Abstract
Producing recombinant mammalian proteins in native or near-native conformation is fundamental to many aspects of biology. Unfortunately, it is also a task whose outcome is extremely unpredictable. A protein that has been shaped over millions of generations of evolution for expression at a level appropriate to a specific cell type or in a particular developmental stage, may be toxic to a new host cell, or become insoluble (among many possible obstacles) when overexpressed in vitro. The object of this volume, "Protein Expression in Mammalian Cells," is to offer guidance for those who wish (or who have been forced by circumstance) to overexpress a mammalian protein in mammalian cells.
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Affiliation(s)
- James L Hartley
- Protein Expression Laboratory, SAIC-Frederick, Inc., National Cancer Institute, Frederick, MD, USA.
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44
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Wilke S, Groebe L, Maffenbeier V, Jäger V, Gossen M, Josewski J, Duda A, Polle L, Owens RJ, Wirth D, Heinz DW, van den Heuvel J, Büssow K. Streamlining homogeneous glycoprotein production for biophysical and structural applications by targeted cell line development. PLoS One 2011; 6:e27829. [PMID: 22174749 PMCID: PMC3235087 DOI: 10.1371/journal.pone.0027829] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 10/26/2011] [Indexed: 11/19/2022] Open
Abstract
Studying the biophysical characteristics of glycosylated proteins and solving their three-dimensional structures requires homogeneous recombinant protein of high quality.We introduce here a new approach to produce glycoproteins in homogenous form with the well-established, glycosylation mutant CHO Lec3.2.8.1 cells. Using preparative cell sorting, stable, high-expressing GFP 'master' cell lines were generated that can be converted fast and reliably by targeted integration via Flp recombinase-mediated cassette exchange (RMCE) to produce any glycoprotein. Small-scale transient transfection of HEK293 cells was used to identify genetically engineered constructs suitable for constructing stable cell lines. Stable cell lines expressing 10 different proteins were established. The system was validated by expression, purification, deglycosylation and crystallization of the heavily glycosylated luminal domains of lysosome-associated membrane proteins (LAMP).
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Affiliation(s)
- Sonja Wilke
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Lothar Groebe
- Department of Experimental Immunology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Vitali Maffenbeier
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Volker Jäger
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Manfred Gossen
- Max Delbrück Center for Molecular Medicine (MDC), Berlin, Germany
- Berlin-Brandenburg Centre for Regenerative Therapies (BCRT), Berlin, Germany
| | - Jörn Josewski
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Agathe Duda
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Lilia Polle
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Raymond J. Owens
- Division of Structural Biology, Henry Wellcome Building for Genomic Medicine, University of Oxford, Oxford, United Kingdom
- Oxford Protein Production Facility UK, The Research Complex at Harwell, Rutherford Appleton Laboratory Harwell Science and Innovation Campus, Oxfordshire, United Kingdom
| | - Dagmar Wirth
- Department of Gene Regulation and Differentiation, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Dirk W. Heinz
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Joop van den Heuvel
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
| | - Konrad Büssow
- Department of Molecular Structural Biology, Helmholtz Centre for Infection Research, Braunschweig, Germany
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45
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Effect of trichostatin A and 5-Aza-2′-deoxycytidine on transgene reactivation and epigenetic modification in transgenic pig fibroblast cells. Mol Cell Biochem 2011; 355:157-65. [DOI: 10.1007/s11010-011-0849-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 04/20/2011] [Indexed: 10/18/2022]
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46
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Turan S, Galla M, Ernst E, Qiao J, Voelkel C, Schiedlmeier B, Zehe C, Bode J. Recombinase-Mediated Cassette Exchange (RMCE): Traditional Concepts and Current Challenges. J Mol Biol 2011; 407:193-221. [DOI: 10.1016/j.jmb.2011.01.004] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/04/2011] [Accepted: 01/04/2011] [Indexed: 12/18/2022]
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47
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Porter AJ, Racher AJ, Preziosi R, Dickson AJ. Strategies for selecting recombinant CHO cell lines for cGMP manufacturing: improving the efficiency of cell line generation. Biotechnol Prog 2011; 26:1455-64. [PMID: 20623584 DOI: 10.1002/btpr.443] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Transfectants with a wide range of cellular phenotypes are obtained during the process of cell line generation. For the successful manufacture of a therapeutic protein, a means is required to identify a cell line with desirable growth and productivity characteristics from this phenotypically wide-ranging transfectant population. This identification process is on the critical path for first-in-human studies. We have stringently examined a typical selection strategy used to isolate cell lines suitable for cGMP manufacturing. One-hundred and seventy-five transfectants were evaluated as they progressed through the different assessment stages of the selection strategy. High producing cell lines, suitable for cGMP manufacturing, were identified. However, our analyses showed that the frequency of isolation of the highest producing cell lines was low and that ranking positions were not consistent between each assessment stage, suggesting that there is potential to improve upon the strategy. Attempts to increase the frequency of isolation of the 10 highest producing cell lines, by in silico analysis of alternative selection strategies, were unsuccessful. We identified alternative strategies with similar predictive capabilities to the typical selection strategy. One alternate strategy required fewer cell lines to be progressed at the assessment stages but the stochastic nature of the models means that cell line numbers are likely to change between programs. In summary, our studies illuminate the potential for improvement to this and future selection strategies, based around use of assessments that are more informative or that reduce variance, paving the way to improved efficiency of generation of manufacturing cell lines.
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Affiliation(s)
- Alison J Porter
- Lonza Biologics Plc, 228 Bath Road, Slough, Berkshire SL14DX, UK.
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48
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Oberbek A, Matasci M, Hacker DL, Wurm FM. Generation of stable, high-producing CHO cell lines by lentiviral vector-mediated gene transfer in serum-free suspension culture. Biotechnol Bioeng 2010; 108:600-10. [PMID: 20967750 DOI: 10.1002/bit.22968] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Revised: 09/22/2010] [Accepted: 09/30/2010] [Indexed: 12/13/2022]
Abstract
Lentivirus-derived vectors (LVs) were studied for the generation of stable recombinant Chinese hamster ovary (CHO) cell lines. Stable pools and clones expressing the enhanced green fluorescent protein (eGFP) were selected via fluorescence-activated cell sorting (FACS). For comparison, cell pools and cell lines were also generated by transfection, using the LV transfer plasmid alone. The level and stability of eGFP expression was greater in LV-transduced cell lines and pools than in those established by transfection. CHO cells were also infected at two different multiplicities of infection with an LV co-expressing eGFP and a tumor necrosis factor receptor:Fc fusion protein (TNFR:Fc). At 2-day post-infection, clonal cell lines with high eGFP-specific fluorescence were recovered by FACS. These clones co-expressed TNFR:Fc with yields of 50-250 mg/L in 4-day cultures. The recovered cell lines maintained stable expression over 3 months in serum-free suspension culture without selection. In conclusion, LV-mediated gene transfer provided an efficient alternative to plasmid transfection for the generation of stable and high-producing recombinant cell lines.
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Affiliation(s)
- Agata Oberbek
- Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Cellular Biotechnology, Lausanne, Switzerland
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49
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Wilke S, Krausze J, Gossen M, Groebe L, Jäger V, Gherardi E, van den Heuvel J, Büssow K. Glycoprotein production for structure analysis with stable, glycosylation mutant CHO cell lines established by fluorescence-activated cell sorting. Protein Sci 2010; 19:1264-71. [PMID: 20512979 DOI: 10.1002/pro.390] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Stable mammalian cell lines are excellent tools for the expression of secreted and membrane glycoproteins. However, structural analysis of these molecules is generally hampered by the complexity of N-linked carbohydrate side chains. Cell lines with mutations are available that result in shorter and more homogenous carbohydrate chains. Here, we use preparative fluorescence-activated cell sorting (FACS) and site-specific gene excision to establish high-yield glycoprotein expression for structural studies with stable clones derived from the well-established Lec3.2.8.1 glycosylation mutant of the Chinese hamster ovary (CHO) cell line. We exemplify the strategy by describing novel clones expressing single-chain hepatocyte growth factor/scatter factor (HGF/SF, a secreted glycoprotein) and a domain of lysosome-associated membrane protein 3 (LAMP3d). In both cases, stable GFP-expressing cell lines were established by transfection with a genetic construct including a GFP marker and two rounds of cell sorting after 1 and 2 weeks. The GFP marker was subsequently removed by heterologous expression of Flp recombinase. Production of HGF/SF and LAMP3d was stable over several months. 1.2 mg HGF/SF and 0.9 mg LAMP3d were purified per litre of culture, respectively. Homogenous glycoprotein preparations were amenable to enzymatic deglycosylation under native conditions. Purified and deglycosylated LAMP3d protein was readily crystallized. The combination of FACS and gene excision described here constitutes a robust and fast procedure for maximizing the yield of glycoproteins for structural analysis from glycosylation mutant cell lines.
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Affiliation(s)
- Sonja Wilke
- Division of Structural Biology, Helmholtz Centre for Infection Research, 38124 Braunschweig, Germany
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50
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Broll S, Oumard A, Hahn K, Schambach A, Bode J. Minicircle performance depending on S/MAR-nuclear matrix interactions. J Mol Biol 2009; 395:950-65. [PMID: 20004666 DOI: 10.1016/j.jmb.2009.11.066] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/14/2009] [Accepted: 11/30/2009] [Indexed: 12/12/2022]
Abstract
The ideal vector for cell and tissue modification does not depend on integration but rather behaves as an independent functional unit that replicates as an episome. Based on a scaffold/matrix attachment region (S/MAR), we have introduced, in 2006, an approximately 4-kb replicating nonviral minicircle able to exploit the cellular replication machinery in a way reminiscent of ARS vectors. Consisting of only one active transcription unit and the S/MAR, it resists silencing as it is free of prokaryotic vector parts and drug selection markers. The rate of final establishment in the nuclear architecture is moderate but comparable to Epstein-Barr virus-based episomes (<5%). Here, we demonstrate that this parameter can be improved if the host cell chromatin is opened by histone hyperacetylation prior to transfection. It remains unaffected, however, by cell cycle position. Still, this class of episomes revealed intrinsic instability and integration after 5 months of continuous culture. In vivo evolution enabled the effective reduction of S/MAR size from 2 kb to 733 bp (resulting in a minicircle of approximately 3 kb) with largely improved stability and cloning capacity. Investigation of individual clones served to prove persistent and homogenous expression, which is ascribed to stable association with nuclear attachment sites. Optimum expression levels were shown to depend on the authentic usage of a polyadenylation site 3' from the S/MAR as anticipated by the stress-induced duplex destabilization algorithm, which finds increasing use to predict the functional parameters of these systems.
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Affiliation(s)
- Sandra Broll
- Department Molecular Biotechnology/Epigenetic Regulation, Helmholtz Center for Infection Research, Inhoffenstrasse 7, D-38124 Braunschweig, Germany
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