1
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Bauler M, Ferrara F, Lowe B, Beard JA, Wincek C, Wielgosz MM, Park JJ, Shang N, Nandy S, Li C, Langfitt DM, Zhou S, Throm RE. Genetic alteration of SJ293TS cells and modification of serum-free media enhances lentiviral vector production. Mol Ther Methods Clin Dev 2024; 32:101270. [PMID: 38883976 PMCID: PMC11176759 DOI: 10.1016/j.omtm.2024.101270] [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: 01/09/2024] [Accepted: 05/17/2024] [Indexed: 06/18/2024]
Abstract
Successful cell and gene therapy clinical trials have resulted in the US Food and Drug Administration and European Medicines Agency approving their use for treatment of patients with certain types of cancers and monogenetic diseases. These novel therapies, which rely heavily on lentiviral vectors to deliver therapeutic transgenes to patient cells, have driven additional investigations, increasing demand for both pre-clinical and current Good Manufacturing Practices-grade viral vectors. To better support novel studies by improving current production methods, we report the development of a genetically modified HEK293T-based cell line that is null for expression of both Protein Kinase R and Beta-2 microglobulin and grows in suspension using serum-free media, SJ293TS-DPB. Absence of Protein Kinase R increased anti-sense lentiviral vector titers by more than 7-fold, while absence of Beta-2 microglobulin, a key component of major histocompatibility complex class I molecules, has been reported to reduce the immunogenicity of lentiviral particles. Furthermore, we describe an improved methodology for culturing SJ293TS-DPB that facilitates expansion, reduces handling, and increases titers by 2-fold compared with previous methods. SJ293TS-DPB stably produced lentiviral vectors for over 4 months and generated lentiviral vectors that efficiently transduce healthy human donor T cells and CD34+ hematopoietic stem cells.
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Affiliation(s)
- Matthew Bauler
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Francesca Ferrara
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Brandon Lowe
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jordan A Beard
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Chris Wincek
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Matthew M Wielgosz
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Jeoungeun J Park
- Experimental Cell Therapeutics Lab, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Na Shang
- Experimental Cell Therapeutics Lab, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Saikat Nandy
- Biostatistics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Cai Li
- Biostatistics, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Deanna M Langfitt
- Bone Marrow Transplant and Cell Therapy, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Sheng Zhou
- Experimental Cell Therapeutics Lab, St Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Robert E Throm
- Vector Development and Production Laboratory, St Jude Children's Research Hospital, Memphis, TN 38105, USA
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2
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Baquero-Pérez B, Bortoletto E, Rosani U, Delgado-Tejedor A, Medina R, Novoa EM, Venier P, Díez J. Elucidation of the Epitranscriptomic RNA Modification Landscape of Chikungunya Virus. Viruses 2024; 16:945. [PMID: 38932237 PMCID: PMC11209572 DOI: 10.3390/v16060945] [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: 05/02/2024] [Revised: 06/03/2024] [Accepted: 06/06/2024] [Indexed: 06/28/2024] Open
Abstract
The genomes of positive-sense (+) single-stranded RNA (ssRNA) viruses are believed to be subjected to a wide range of RNA modifications. In this study, we focused on the chikungunya virus (CHIKV) as a model (+) ssRNA virus to study the landscape of viral RNA modification in infected human cells. Among the 32 distinct RNA modifications analysed by mass spectrometry, inosine was found enriched in the genomic CHIKV RNA. However, orthogonal validation by Illumina RNA-seq analyses did not identify any inosine modification along the CHIKV RNA genome. Moreover, CHIKV infection did not alter the expression of ADAR1 isoforms, the enzymes that catalyse the adenosine to inosine conversion. Together, this study highlights the importance of a multidisciplinary approach to assess the presence of RNA modifications in viral RNA genomes.
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Affiliation(s)
- Belinda Baquero-Pérez
- Molecular Virology Group, Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - Enrico Bortoletto
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy; (E.B.); (U.R.)
| | - Umberto Rosani
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy; (E.B.); (U.R.)
| | - Anna Delgado-Tejedor
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; (A.D.-T.); (R.M.); (E.M.N.)
| | - Rebeca Medina
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; (A.D.-T.); (R.M.); (E.M.N.)
| | - Eva Maria Novoa
- Center for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr. Aiguader 88, 08003 Barcelona, Spain; (A.D.-T.); (R.M.); (E.M.N.)
- Universitat Pompeu Fabra (UPF), 08003 Barcelona, Spain
| | - Paola Venier
- Department of Biology, University of Padova, Via Ugo Bassi 58/b, 35131 Padova, Italy; (E.B.); (U.R.)
| | - Juana Díez
- Molecular Virology Group, Department of Medicine and Life Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain
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3
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Baldaccini M, Gaucherand L, Chane-Woon-Ming B, Messmer M, Gucciardi F, Pfeffer S. The helicase domain of human Dicer prevents RNAi-independent activation of antiviral and inflammatory pathways. EMBO J 2024; 43:806-835. [PMID: 38287188 PMCID: PMC10907635 DOI: 10.1038/s44318-024-00035-2] [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: 10/04/2023] [Revised: 12/19/2023] [Accepted: 01/08/2024] [Indexed: 01/31/2024] Open
Abstract
In mammalian somatic cells, the relative contribution of RNAi and the type I interferon response during viral infection is unclear. The apparent inefficiency of antiviral RNAi might be due to self-limiting properties and mitigating co-factors of the key enzyme Dicer. In particular, the helicase domain of human Dicer appears to be an important restriction factor of its activity. Here, we study the involvement of several helicase-truncated mutants of human Dicer in the antiviral response. All deletion mutants display a PKR-dependent antiviral phenotype against certain viruses, and one of them, Dicer N1, acts in a completely RNAi-independent manner. Transcriptomic analyses show that many genes from the interferon and inflammatory response pathways are upregulated in Dicer N1 expressing cells. We show that some of these genes are controlled by NF-kB and that blocking this pathway abrogates the antiviral phenotype of Dicer N1. Our findings highlight the crosstalk between Dicer, PKR, and the NF-kB pathway, and suggest that human Dicer may have repurposed its helicase domain to prevent basal activation of antiviral and inflammatory pathways.
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Affiliation(s)
- Morgane Baldaccini
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France
| | - Léa Gaucherand
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France
| | - Béatrice Chane-Woon-Ming
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France
| | - Mélanie Messmer
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France
| | - Floriane Gucciardi
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France
| | - Sébastien Pfeffer
- Université de Strasbourg, Architecture et Réactivité de l'ARN, Institut de Biologie Moléculaire et Cellulaire du CNRS, 67000, Strasbourg, France.
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4
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František Potužník J, Nešuta O, Škríba A, Voleníková B, Mititelu MB, Mancini F, Serianni V, Fernandez H, Spustová K, Trylčová J, Vopalensky P, Cahová H. Diadenosine Tetraphosphate (Ap 4 A) Serves as a 5' RNA Cap in Mammalian Cells. Angew Chem Int Ed Engl 2024; 63:e202314951. [PMID: 37934413 DOI: 10.1002/anie.202314951] [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: 10/05/2023] [Revised: 11/02/2023] [Accepted: 11/07/2023] [Indexed: 11/08/2023]
Abstract
The recent expansion of the field of RNA chemical modifications has changed our understanding of post-transcriptional gene regulation. Apart from internal nucleobase modifications, 7-methylguanosine was long thought to be the only eukaryotic RNA cap. However, the discovery of non-canonical RNA caps in eukaryotes revealed a new niche of previously undetected RNA chemical modifications. We are the first to report the existence of a new non-canonical RNA cap, diadenosine tetraphosphate (Ap4 A), in human and rat cell lines. Ap4 A is the most abundant dinucleoside polyphosphate in eukaryotic cells and can be incorporated into RNA by RNA polymerases as a non-canonical initiating nucleotide (NCIN). Using liquid chromatography-mass spectrometry (LC-MS), we show that the amount of capped Ap4 A-RNA is independent of the cellular concentration of Ap4 A. A decapping enzyme screen identifies two enzymes cleaving Ap4 A-RNA,NUDT2 and DXO, both of which also cleave other substrate RNAs in vitro. We further assess the translatability and immunogenicity of Ap4 A-RNA and show that although it is not translated, Ap4 A-RNA is recognized as self by the cell and does not elicit an immune response, making it a natural component of the transcriptome. Our findings open a previously unexplored area of eukaryotic RNA regulation.
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Affiliation(s)
- Jiří František Potužník
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague, 2, Czechia
| | - Ondřej Nešuta
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Anton Škríba
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Barbora Voleníková
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Maria-Bianca Mititelu
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague, 2, Czechia
| | - Flaminia Mancini
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague, 2, Czechia
| | - Valentina Serianni
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
- Department of Cell Biology, Faculty of Science, Charles University, Viničná 7, Prague, 2, Czechia
| | - Henri Fernandez
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Kristína Spustová
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Jana Trylčová
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Pavel Vopalensky
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
| | - Hana Cahová
- Chemical Biology of Nucleic, Acids, Institute of Organic Chemistry and Biochemistry of the CAS, Flemingovo náměstí 2, Prague, 6, Czechia
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5
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He Z, Kwee EJ, Cleveland MH, Cole KD, Lin-Gibson S, He HJ. Quantitation and integrity evaluation of RNA genome in lentiviral vectors by direct reverse transcription-droplet digital PCR (direct RT-ddPCR). Sci Rep 2023; 13:14470. [PMID: 37660227 PMCID: PMC10475045 DOI: 10.1038/s41598-023-41644-x] [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: 06/05/2023] [Accepted: 08/29/2023] [Indexed: 09/04/2023] Open
Abstract
Lentiviral vectors (LV) have proven to be powerful tools for stable gene delivery in both dividing and non-dividing cells. Approval of these LVs for use in clinical applications has been achieved by improvements in LV design. Critically important characteristics concerning quality control are LV titer quantification and the detection of impurities. However, increasing evidence concerning high variability in titration assays indicates poor harmonization of the methods undertaken to date. In this study, we developed a direct reverse transcription droplet digital PCR (Direct RT-ddPCR) approach without RNA extraction and purification for estimation of LV titer and RNA genome integrity. The RNA genome integrity was assessed by RT-ddPCR assays targeted to four distant regions of the LV genome. Results of the analyses showed that direct RT-ddPCR without RNA extraction and purification performs similarly to RT-ddPCR on purified RNA from 3 different LV samples, in terms of robustness and assay variance. Interestingly, these RNA titer results were comparable to physical titers by p24 antigen ELISA (enzyme-linked immunosorbent assay). Moreover, we confirmed the partial degradation or the incomplete RNA genomes in the prepared 3 LV samples. These results may partially explain the discrepancy of the LV particle titers to functional titers. This work not only demonstrates the feasibility of direct RT-ddPCR in determining LV titers, but also provides a method that can be easily adapted for RNA integrity assessment.
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Affiliation(s)
- Zhiyong He
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA.
| | - Edward J Kwee
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA
| | - Megan H Cleveland
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA
| | - Kenneth D Cole
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA
| | - Sheng Lin-Gibson
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA
| | - Hua-Jun He
- Material Measurement Laboratory, National Institute of Standards and Technology, 100 Bureau Drive, MS 8312, Gaithersburg, MD, 20899, USA.
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6
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Reichenbach P, Giordano Attianese GMP, Ouchen K, Cribioli E, Triboulet M, Ash S, Saillard M, Vuillefroy de Silly R, Coukos G, Irving M. A lentiviral vector for the production of T cells with an inducible transgene and a constitutively expressed tumour-targeting receptor. Nat Biomed Eng 2023; 7:1063-1080. [PMID: 37069267 PMCID: PMC10504085 DOI: 10.1038/s41551-023-01013-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 02/20/2023] [Indexed: 04/19/2023]
Abstract
Vectors that facilitate the engineering of T cells that can better harness endogenous immunity and overcome suppressive barriers in the tumour microenvironment would help improve the safety and efficacy of T-cell therapies for more patients. Here we report the design, production and applicability, in T-cell engineering, of a lentiviral vector leveraging an antisense configuration and comprising a promoter driving the constitutive expression of a tumour-directed receptor and a second promoter enabling the efficient activation-inducible expression of a genetic payload. The vector allows for the delivery of a variety of genes to human T cells, as we show for interleukin-2 and a microRNA-based short hairpin RNA for the knockdown of the gene coding for haematopoietic progenitor kinase 1, a negative regulator of T-cell-receptor signalling. We also show that a gene encoded under an activation-inducible promoter is specifically expressed by tumour-redirected T cells on encountering a target antigen in the tumour microenvironment. The single two-gene-encoding vector can be produced at high titres under an optimized protocol adaptable to good manufacturing practices.
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Affiliation(s)
- Patrick Reichenbach
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Greta Maria Paola Giordano Attianese
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Khaoula Ouchen
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Elisabetta Cribioli
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Melanie Triboulet
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Sarah Ash
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Margaux Saillard
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Romain Vuillefroy de Silly
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - George Coukos
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
| | - Melita Irving
- Department of Oncology, Ludwig Institute for Cancer Research Lausanne, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland.
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7
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Wang Y, Shao W. Innate Immune Response to Viral Vectors in Gene Therapy. Viruses 2023; 15:1801. [PMID: 37766208 PMCID: PMC10536768 DOI: 10.3390/v15091801] [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: 07/12/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 09/29/2023] Open
Abstract
Viral vectors play a pivotal role in the field of gene therapy, with several related drugs having already gained clinical approval from the EMA and FDA. However, numerous viral gene therapy vectors are currently undergoing pre-clinical research or participating in clinical trials. Despite advancements, the innate response remains a significant barrier impeding the clinical development of viral gene therapy. The innate immune response to viral gene therapy vectors and transgenes is still an important reason hindering its clinical development. Extensive studies have demonstrated that different DNA and RNA sensors can detect adenoviruses, adeno-associated viruses, and lentiviruses, thereby activating various innate immune pathways such as Toll-like receptor (TLR), cyclic GMP-AMP synthase-stimulator of interferon genes (cGAS-STING), and retinoic acid-inducible gene I-mitochondrial antiviral signaling protein (RLR-MAVS). This review focuses on elucidating the mechanisms underlying the innate immune response induced by three widely utilized viral vectors: adenovirus, adeno-associated virus, and lentivirus, as well as the strategies employed to circumvent innate immunity.
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Affiliation(s)
| | - Wenwei Shao
- Academy of Medical Engineering and Translational Medicine, Medical College, Tianjin University, Tianjin 300072, China;
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8
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Song Z, Zhang G, Huang S, Liu Y, Li G, Zhou X, Sun J, Gao P, Chen Y, Huang X, Liu J, Wang X. PE-STOP: A versatile tool for installing nonsense substitutions amenable for precise reversion. J Biol Chem 2023; 299:104942. [PMID: 37343700 PMCID: PMC10365944 DOI: 10.1016/j.jbc.2023.104942] [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: 04/03/2023] [Revised: 06/08/2023] [Accepted: 06/11/2023] [Indexed: 06/23/2023] Open
Abstract
The rapid advances in genome editing technologies have revolutionized the study of gene functions in cell or animal models. The recent generation of double-stranded DNA cleavage-independent base editors has been suitably adapted for interrogation of protein-coding genes on the basis of introducing premature stop codons or disabling the start codons. However, such versions of stop/start codon-oriented genetic tools still present limitations on their versatility, base-level precision, and target specificity. Here, we exploit a newly developed prime editor (PE) that differs from base editors by its adoption of a reverse transcriptase activity, which enables incorporation of various types of precise edits templated by a specialized prime editing guide RNA. Based on such a versatile platform, we established a prime editing-empowered method (PE-STOP) for installation of nonsense substitutions, providing a complementary approach to the present gene-targeting tools. PE-STOP is bioinformatically predicted to feature substantially expanded coverage in the genome space. In practice, PE-STOP introduces stop codons with good efficiencies in human embryonic kidney 293T and N2a cells (with medians of 29% [ten sites] and 25% [four sites] editing efficiencies, respectively), while exhibiting minimal off-target effects and high on-target precision. Furthermore, given the fact that PE installs prime editing guide RNA-templated mutations, we introduce a unique strategy for precise genetic rescue of PE-STOP-dependent nonsense mutation via the same PE platform. Altogether, the present work demonstrates a versatile and specific tool for gene inactivation and for functional interrogation of nonsense mutations.
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Affiliation(s)
- Ziguo Song
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Guiquan Zhang
- Zhejiang Lab, Hangzhou, Zhejiang, China; State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center at Medical School of Nanjing University, Nanjing, China
| | - Shuhong Huang
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Yao Liu
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Guanglei Li
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Xianhui Zhou
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Jiayuan Sun
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Pengfei Gao
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China
| | - Yulin Chen
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Livestock Biology, Northwest A&F University, Yangling, Shaanxi, China
| | - Xingxu Huang
- Zhejiang Lab, Hangzhou, Zhejiang, China; School of Life Science and Technology, ShanghaiTech University, Shanghai, China; CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, Shanghai, China
| | - Jianghuai Liu
- State Key Laboratory of Pharmaceutical Biotechnology and MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center at Medical School of Nanjing University, Nanjing, China.
| | - Xiaolong Wang
- International Joint Agriculture Research Center for Animal Bio-Breeding of Ministry of Agriculture and Rural Affairs, College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi, China; Key Laboratory of Livestock Biology, Northwest A&F University, Yangling, Shaanxi, China.
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9
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Iaffaldano BJ, Marino MP, Reiser J. CRISPR library screening to develop HEK293-derived cell lines with improved lentiviral vector titers. Front Genome Ed 2023; 5:1218328. [PMID: 37520398 PMCID: PMC10373892 DOI: 10.3389/fgeed.2023.1218328] [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: 05/07/2023] [Accepted: 07/03/2023] [Indexed: 08/01/2023] Open
Abstract
Lentiviral (LV) vectors have emerged as powerful tools for treating genetic and acquired human diseases. As clinical studies and commercial demands have progressed, there has been a growing need for large amounts of purified LV vectors. To help meet this demand, we developed CRISPR library screening methods to identify genetic perturbations in human embryonic kidney 293 (HEK293) cells and their derivatives that may increase LV vector titers. Briefly, LV vector-based Human CRISPR Activation and Knockout libraries (Calabrese and Brunello) were used to modify HEK293 and HEK293T cells. These cell populations were then expanded, and integrated LV vector genomes were rescued by transfection. LV vectors were harvested, and the process of sequential transduction and rescue-transfection was iterated. Through this workflow, guide RNAs (gRNAs) that target genes that may suppress or enhance LV vector production were enriched and identified with Next-Generation Sequencing (NGS). Though more work is needed to test genes identified in this screen, we expect that perturbations of genes we identified here, such as TTLL12, which is an inhibitor of antiviral innate immunity may be introduced and multiplexed to yield cell lines with improved LV vector productivity.
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10
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Chung CH, Murphy CM, Wingate VP, Pavlicek JW, Nakashima R, Wei W, McCarty D, Rabinowitz J, Barton E. Production of rAAV by plasmid transfection induces antiviral and inflammatory responses in suspension HEK293 cells. Mol Ther Methods Clin Dev 2023; 28:272-283. [PMID: 36819978 PMCID: PMC9937832 DOI: 10.1016/j.omtm.2023.01.002] [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: 11/09/2022] [Accepted: 01/13/2023] [Indexed: 01/18/2023]
Abstract
Recombinant adeno-associated virus (rAAV) is a clinically proven viral vector for delivery of therapeutic genes to treat rare diseases. Improving rAAV manufacturing productivity and vector quality is necessary to meet clinical and commercial demand. These goals will require an improved understanding of the cellular response to rAAV production, which is poorly defined. We interrogated the kinetic transcriptional response of HEK293 cells to rAAV production following transient plasmid transfection, under manufacturing-relevant conditions, using RNA-seq. Time-series analyses identified a robust cellular response to transfection and rAAV production, with 1,850 transcripts differentially expressed. Gene Ontology analysis determined upregulated pathways, including inflammatory and antiviral responses, with several interferon-stimulated cytokines and chemokines being upregulated at the protein level. Literature-based pathway prediction implicated multiple pathogen pattern sensors and signal transducers in up-regulation of inflammatory and antiviral responses in response to transfection and rAAV replication. Systematic analysis of the cellular transcriptional response to rAAV production indicates that host cells actively sense vector manufacture as an infectious insult. This dataset may therefore illuminate genes and pathways that influence rAAV production, thereby enabling the rational design of next-generation manufacturing platforms to support safe, effective, and affordable AAV-based gene therapies.
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Affiliation(s)
- Cheng-Han Chung
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA
| | - Christopher M. Murphy
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA
| | - Vincent P. Wingate
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA
| | - Jeffrey W. Pavlicek
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA
| | - Reiko Nakashima
- Pfizer Inc., Worldwide Research, Development and Medical, Simulation and Modeling Sciences, Cambridge, MA 02139, USA
| | - Wei Wei
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA
| | - Douglas McCarty
- Pfizer Inc., Worldwide Research, Development and Medical, Rare Disease Research Unit, Morrisville, NC 27560, USA
| | - Joseph Rabinowitz
- Pfizer Inc., Worldwide Research, Development and Medical, Rare Disease Research Unit, Morrisville, NC 27560, USA
| | - Erik Barton
- Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA,Corresponding author: Erik Barton, Pfizer Inc., Worldwide Research, Development and Medical, Bioprocess Research and Development, Morrisville, NC 27560, USA.
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11
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Aggarwal A, Akerman A, Milogiannakis V, Silva MR, Walker G, Stella AO, Kindinger A, Angelovich T, Waring E, Amatayakul-Chantler S, Roth N, Manni S, Hauser T, Barnes T, Condylios A, Yeang M, Wong M, Jean T, Foster CSP, Christ D, Hoppe AC, Munier ML, Darley D, Churchill M, Stark DJ, Matthews G, Rawlinson WD, Kelleher AD, Turville SG. SARS-CoV-2 Omicron BA.5: Evolving tropism and evasion of potent humoral responses and resistance to clinical immunotherapeutics relative to viral variants of concern. EBioMedicine 2022; 84:104270. [PMID: 36130476 PMCID: PMC9482529 DOI: 10.1016/j.ebiom.2022.104270] [Citation(s) in RCA: 60] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/09/2022] [Accepted: 09/02/2022] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Genetically distinct viral variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recorded since January 2020. The introduction of global vaccine programs has contributed to lower COVID-19 hospitalisation and mortality rates, particularly in developed countries. In late 2021, Omicron BA.1 emerged, with substantially altered genetic differences and clinical effects from other variants of concern. Shortly after dominating global spread in early 2022, BA.1 was supplanted by the genetically distinct Omicron lineage BA.2. A sub-lineage of BA.2, designated BA.5, presently has an outgrowth advantage over BA.2 and other BA.2 sub-lineages. Here we study the neutralisation of Omicron BA.1, BA.2 and BA.5 and pre-Omicron variants using a range of vaccine and convalescent sera and therapeutic monoclonal antibodies using a live virus neutralisation assay. Using primary nasopharyngeal swabs, we also tested the relative fitness of BA.5 compared to pre-Omicron and Omicron viral lineages in their ability to use the ACE2-TMPRSS2 pathway. METHODS Using low passage clinical isolates of Clade A.2.2, Beta, Delta, BA.1, BA.2 and BA.5, we determined humoral neutralisation in vitro in vaccinated and convalescent cohorts, using concentrated human IgG pooled from thousands of plasma donors, and licensed monoclonal antibody therapies. We then determined infectivity to particle ratios in primary nasopharyngeal samples and expanded low passage isolates in a genetically engineered ACE2/TMPRSS2 cell line in the presence and absence of the TMPRSS2 inhibitor Nafamostat. FINDINGS Peak responses to 3 doses of BNT162b2 vaccine were associated with a 9-fold reduction in neutralisation for Omicron lineages BA.1, BA.2 and BA.5. Concentrated pooled human IgG from convalescent and vaccinated donors and BNT162b2 vaccination with BA.1 breakthrough infections were associated with greater breadth of neutralisation, although the potency was still reduced 7-fold across all Omicron lineages. Testing of clinical grade antibodies revealed a 14.3-fold reduction using Evusheld and 16.8-fold reduction using Sotrovimab for the BA.5. Whilst the infectivity of BA.1 and BA.2 was attenuated in ACE2/TMPRSS2 entry, BA.5 was observed to be equivalent to that of an early 2020 circulating clade and had greater sensitivity to the TMPRSS2 inhibitor Nafamostat. INTERPRETATION Observations support all Omicron variants to significantly escape neutralising antibodies across a range of vaccination and/or convalescent responses. Potency of therapeutic monoclonal antibodies is also reduced and differs across Omicron lineages. The key difference of BA.5 from other Omicron sub-variants is the reversion in tropism back to using the well-known ACE2-TMPRSS2 pathway, utilised efficiently by pre-Omicron lineages. Monitoring if these changes influence transmission and/or disease severity will be key for ongoing tracking and management of Omicron waves globally. FUNDING This work was primarily supported by Australian Medical Foundation research grants MRF2005760 (ST, GM & WDR), MRF2001684 (ADK and ST) and Medical Research Future Fund Antiviral Development Call grant (WDR), Medical Research Future Fund COVID-19 grant (MRFF2001684, ADK & SGT) and the New South Wales Health COVID-19 Research Grants Round 2 (SGT).
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Affiliation(s)
- Anupriya Aggarwal
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Anouschka Akerman
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | | | - Mariana Ruiz Silva
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Gregory Walker
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | | | - Andrea Kindinger
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Thomas Angelovich
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | - Emily Waring
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | | | - Nathan Roth
- Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Sandro Manni
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Thomas Hauser
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Thomas Barnes
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Anna Condylios
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Malinna Yeang
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Maureen Wong
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Tyra Jean
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Charles S P Foster
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Daniel Christ
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | | | - Mee Ling Munier
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - David Darley
- St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Melissa Churchill
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | - Damien J Stark
- Molecular Diagnostic Medicine Laboratory, Sydpath, St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Gail Matthews
- The Kirby Institute, University of New South Wales, New South Wales, Australia; St Vincent's Hospital, Sydney, New South Wales, Australia
| | - William D Rawlinson
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Anthony D Kelleher
- The Kirby Institute, University of New South Wales, New South Wales, Australia; St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Stuart G Turville
- The Kirby Institute, University of New South Wales, New South Wales, Australia.
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12
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Aggarwal A, Akerman A, Milogiannakis V, Silva MR, Walker G, Stella AO, Kindinger A, Angelovich T, Waring E, Amatayakul-Chantler S, Roth N, Manni S, Hauser T, Barnes T, Condylios A, Yeang M, Wong M, Jean T, Foster CSP, Christ D, Hoppe AC, Munier ML, Darley D, Churchill M, Stark DJ, Matthews G, Rawlinson WD, Kelleher AD, Turville SG. SARS-CoV-2 Omicron BA.5: Evolving tropism and evasion of potent humoral responses and resistance to clinical immunotherapeutics relative to viral variants of concern. EBioMedicine 2022; 84:104270. [PMID: 36130476 DOI: 10.1101/2021.12.14.21267772] [Citation(s) in RCA: 41] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 08/09/2022] [Accepted: 09/02/2022] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND Genetically distinct viral variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been recorded since January 2020. The introduction of global vaccine programs has contributed to lower COVID-19 hospitalisation and mortality rates, particularly in developed countries. In late 2021, Omicron BA.1 emerged, with substantially altered genetic differences and clinical effects from other variants of concern. Shortly after dominating global spread in early 2022, BA.1 was supplanted by the genetically distinct Omicron lineage BA.2. A sub-lineage of BA.2, designated BA.5, presently has an outgrowth advantage over BA.2 and other BA.2 sub-lineages. Here we study the neutralisation of Omicron BA.1, BA.2 and BA.5 and pre-Omicron variants using a range of vaccine and convalescent sera and therapeutic monoclonal antibodies using a live virus neutralisation assay. Using primary nasopharyngeal swabs, we also tested the relative fitness of BA.5 compared to pre-Omicron and Omicron viral lineages in their ability to use the ACE2-TMPRSS2 pathway. METHODS Using low passage clinical isolates of Clade A.2.2, Beta, Delta, BA.1, BA.2 and BA.5, we determined humoral neutralisation in vitro in vaccinated and convalescent cohorts, using concentrated human IgG pooled from thousands of plasma donors, and licensed monoclonal antibody therapies. We then determined infectivity to particle ratios in primary nasopharyngeal samples and expanded low passage isolates in a genetically engineered ACE2/TMPRSS2 cell line in the presence and absence of the TMPRSS2 inhibitor Nafamostat. FINDINGS Peak responses to 3 doses of BNT162b2 vaccine were associated with a 9-fold reduction in neutralisation for Omicron lineages BA.1, BA.2 and BA.5. Concentrated pooled human IgG from convalescent and vaccinated donors and BNT162b2 vaccination with BA.1 breakthrough infections were associated with greater breadth of neutralisation, although the potency was still reduced 7-fold across all Omicron lineages. Testing of clinical grade antibodies revealed a 14.3-fold reduction using Evusheld and 16.8-fold reduction using Sotrovimab for the BA.5. Whilst the infectivity of BA.1 and BA.2 was attenuated in ACE2/TMPRSS2 entry, BA.5 was observed to be equivalent to that of an early 2020 circulating clade and had greater sensitivity to the TMPRSS2 inhibitor Nafamostat. INTERPRETATION Observations support all Omicron variants to significantly escape neutralising antibodies across a range of vaccination and/or convalescent responses. Potency of therapeutic monoclonal antibodies is also reduced and differs across Omicron lineages. The key difference of BA.5 from other Omicron sub-variants is the reversion in tropism back to using the well-known ACE2-TMPRSS2 pathway, utilised efficiently by pre-Omicron lineages. Monitoring if these changes influence transmission and/or disease severity will be key for ongoing tracking and management of Omicron waves globally. FUNDING This work was primarily supported by Australian Medical Foundation research grants MRF2005760 (ST, GM & WDR), MRF2001684 (ADK and ST) and Medical Research Future Fund Antiviral Development Call grant (WDR), Medical Research Future Fund COVID-19 grant (MRFF2001684, ADK & SGT) and the New South Wales Health COVID-19 Research Grants Round 2 (SGT).
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Affiliation(s)
- Anupriya Aggarwal
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Anouschka Akerman
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | | | - Mariana Ruiz Silva
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Gregory Walker
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | | | - Andrea Kindinger
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - Thomas Angelovich
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | - Emily Waring
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | | | - Nathan Roth
- Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Sandro Manni
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Thomas Hauser
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Thomas Barnes
- Department of Bioanalytical Sciences, Plasma Product Development, Research & Development, CSL Behring AG, Bern, Switzerland
| | - Anna Condylios
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Malinna Yeang
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Maureen Wong
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Tyra Jean
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Charles S P Foster
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Daniel Christ
- Garvan Institute of Medical Research, Sydney, New South Wales, Australia
| | | | - Mee Ling Munier
- The Kirby Institute, University of New South Wales, New South Wales, Australia
| | - David Darley
- St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Melissa Churchill
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Australia
| | - Damien J Stark
- Molecular Diagnostic Medicine Laboratory, Sydpath, St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Gail Matthews
- The Kirby Institute, University of New South Wales, New South Wales, Australia; St Vincent's Hospital, Sydney, New South Wales, Australia
| | - William D Rawlinson
- Serology and Virology Division (SAViD), NSW Health Pathology, Randwick, Australia
| | - Anthony D Kelleher
- The Kirby Institute, University of New South Wales, New South Wales, Australia; St Vincent's Hospital, Sydney, New South Wales, Australia
| | - Stuart G Turville
- The Kirby Institute, University of New South Wales, New South Wales, Australia.
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13
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Platform for isolation and characterization of SARS-CoV-2 variants enables rapid characterization of Omicron in Australia. Nat Microbiol 2022; 7:896-908. [PMID: 35637329 PMCID: PMC9159941 DOI: 10.1038/s41564-022-01135-7] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 04/26/2022] [Indexed: 01/31/2023]
Abstract
Genetically distinct variants of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have emerged since the start of the COVID-19 pandemic. Over this period, we developed a rapid platform (R-20) for viral isolation and characterization using primary remnant diagnostic swabs. This, combined with quarantine testing and genomics surveillance, enabled the rapid isolation and characterization of all major SARS-CoV-2 variants circulating in Australia in 2021. Our platform facilitated viral variant isolation, rapid resolution of variant fitness using nasopharyngeal swabs and ranking of evasion of neutralizing antibodies. In late 2021, variant of concern Omicron (B1.1.529) emerged. Using our platform, we detected and characterized SARS-CoV-2 VOC Omicron. We show that Omicron effectively evades neutralization antibodies and has a different entry route that is TMPRSS2-independent. Our low-cost platform is available to all and can detect all variants of SARS-CoV-2 studied so far, with the main limitation being that our platform still requires appropriate biocontainment. A platform developed for rapid isolation of SARS-CoV-2 variants also facilitates the characterization of variant immune evasion and viral fitness. The platform enabled rapid detection of the Omicron variant in samples of the first cases in Australia.
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14
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Nguyen DB, Tran HT, Kaestner L, Bernhardt I. The Relation Between Extracellular Vesicles Released From Red Blood Cells, Their Cargo, and the Clearance by Macrophages. Front Physiol 2022; 13:783260. [PMID: 35432007 PMCID: PMC9008836 DOI: 10.3389/fphys.2022.783260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 02/14/2022] [Indexed: 12/12/2022] Open
Abstract
Extracellular vesicles (EVs) are cell-derived membrane particles that include exosomes, ectosomes, microvesicles, microparticles, apoptotic bodies, and other EV subsets. EVs are involved in intercellular communication and the transport of macromolecules between cells. Here, we propose and test the ability of red blood cell (RBC)-derived EVs (RBC-EVs) as putative drug carriers. EVs were produced by treating RBCs with Phorbol-12-myristate-13-acetate (PMA) and separating from the cells by differential centrifugation steps. RBC-EVs were characterized by size determination, flow cytometry, and scanning electron microscopy (SEM). EVs were loaded with DNA plasmids coding for the green fluorescent protein (GFP) by electroporation. The DNA-loaded EVs (DNA-EVs) were used to transfect THP-1-derived macrophages and analyzed by fluorescence microscopy and flow cytometry. The results showed that RBC-EVs had an almost spherical shape and a polydispersity in their size with an average of 197 ± 44 nm and with a zeta potential of −36 ± 8 mV. RBC-EVs were successfully loaded with DNA but associated with an increase of the polydispersity index (PdI) and showed a positive signal with Picogreen. DNA-EVs were almost completely taken up by macrophages within 24 h, however, resulting in the expression of the GFP in a subpopulation of macrophages. As the way, we designed that RBC-EVs could be potential nucleic acid carriers when the immune system was addressed. This study may contribute to the understanding of the role of EVs in the development of microvesicle-based vehicles.
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Affiliation(s)
- Duc Bach Nguyen
- Department of Molecular Biology, Faculty of Biotechnology, Vietnam National University of Agriculture, Hanoi, Vietnam
- *Correspondence: Duc Bach Nguyen,
| | - Hanh Triet Tran
- Division of Aquacultural Biotechnology, Biotechnology Center of Ho Chi Minh City, Ho Chi Minh City, Vietnam
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Medical Faculty, Saarland University, Homburg, Germany
- Dynamics of Fluids, Experimental Physics, Saarland University, Saarbruecken, Germany
| | - Ingolf Bernhardt
- Laboratory of Biophysics, Faculty of Natural and Technical Sciences, Saarland University, Saarbruecken, Germany
- Ingolf Bernhardt,
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15
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Han J, Tam K, Tam C, Hollis RP, Kohn DB. Improved lentiviral vector titers from a multi-gene knockout packaging line. Mol Ther Oncolytics 2021; 23:582-592. [PMID: 34938858 PMCID: PMC8660686 DOI: 10.1016/j.omto.2021.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 11/18/2021] [Indexed: 01/01/2023] Open
Abstract
Lentiviral vectors (LVs) are robust delivery vehicles for gene therapy as they can efficiently integrate transgenes into host cell genomes. However, LVs with lengthy or complex expression cassettes typically are produced at low titers and have reduced gene transfer capacity, creating barriers for clinical and commercial applications. Modifications of the packaging cell line and methods may be able to produce complex vectors at higher titer and infectivity and may improve production of many different LVs. In this study, we identified two host restriction factors in HEK293T packaging cells that impeded LV production, 2'-5'-oligoadenylate synthetase 1 (OAS1) and low-density lipoprotein receptor (LDLR). Knocking out these two genes separately led to ∼2-fold increases in viral titer. We created a monoclonal cell line, CRISPRed HEK293T to Disrupt Antiviral Response (CHEDAR), by successively knocking out OAS1, LDLR, and PKR, a previously identified factor impeding LV titers. Packaging in CHEDAR yielded ∼7-fold increases in physical particles, full-length vector RNA, and vector titers. In addition, overexpressing transcription elongation factors, SPT4 and SPT5, during packaging improved the production of full-length vector RNA, thereby increasing titers by ∼2-fold. Packaging in CHEDAR with over-expression of SPT4 and SPT5 led to ∼11-fold increases of titers. These approaches improved the production of a variety of LVs, especially vectors with low titers or with internal promoters in the reverse orientation, and may be beneficial for multiple gene therapy applications.
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Affiliation(s)
- Jiaying Han
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Kevin Tam
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Curtis Tam
- Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, CA 90095, USA
| | - Roger P. Hollis
- Department of Microbiology, Immunology & Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
| | - Donald B. Kohn
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Microbiology, Immunology & Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- Department of Pediatrics, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA
- The Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los Angeles, CA 90095, USA
- UCLA Jonsson Comprehensive Cancer Center, Los Angeles, CA 90095, USA
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16
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Facile method for delivering chikungunya viral replicons into mosquitoes and mammalian cells. Sci Rep 2021; 11:12321. [PMID: 34112897 PMCID: PMC8192953 DOI: 10.1038/s41598-021-91830-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 06/01/2021] [Indexed: 11/09/2022] Open
Abstract
Reverse genetics is an important tool in the elucidation of viral replication and the development of countermeasures; however, these methods are impeded by laborious and inefficient replicon delivery methods. This paper demonstrates the use of a baculovirus to facilitate the efficient delivery of autonomous CHIKV replicons into mosquito and mammalian cells in vitro as well as adult mosquitoes in vivo. The efficacy of this approach was verified via co-localization among an eGFP reporter, nsP1, and dsRNA as well as through the inhibition of an RNA-dependent RNA polymerase (RdRp) null mutation (DDAA) in nsP4, or the treatment of a known antiviral compound (6-azauridine). We also investigated the correlation between CHIKV replicon-launched eGFP expression and the effectiveness of CHIKV replicon variants in inducing IFN-β expression in human cell lines. This delivery method based on a single vector is applicable to mosquito and mammalian cells in seeking to decipher the mechanisms underlying CHIKV replication, elucidate virus-host interactions, and develop antivirals. This study presents an effective alternative to overcome many of the technological issues related to the study and utilization of autonomous arbovirus replicons.
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17
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Pulix M, Lukashchuk V, Smith DC, Dickson AJ. Molecular characterization of HEK293 cells as emerging versatile cell factories. Curr Opin Biotechnol 2021; 71:18-24. [PMID: 34058525 DOI: 10.1016/j.copbio.2021.05.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/29/2021] [Accepted: 05/07/2021] [Indexed: 01/27/2023]
Abstract
HEK293 cell lines are used for the production of recombinant proteins, virus-like particles and viral vectors. Recent work has generated molecular (systems level) characterisation of HEK293 variants that has enabled re-engineering of the cells towards enhanced use for manufacture-scale production of recombinant biopharmaceuticals (assessment of 'safe harbours' for gene insertion, engineering of new variants for stable, amplifiable expression). In parallel, there have been notable advances in the bioprocessing conditions (suspension adaptation, development of defined serum-free media) that offer the potential for large-scale manufacture, a feature especially important in the drive to produce viral vectors at large-scale and at commercially viable costs for gene therapy. The combination of cell-based and bioprocess-based modification of existing HEK293 cell processes, frequently informed by understandings transferred from developments with Chinese hamster ovary cell lines, seems destined to place the HEK293 cell systems firmly as a critical platform for production of future biologically based therapeutics.
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Affiliation(s)
- Michela Pulix
- Manchester Institute of Biotechnology, Faculty of Science and Engineering, Department of Chemical Engineering & Analytical Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK; Cobra Biologics, Stephenson Building, Keele Science Park, Keele ST5 5SP, UK
| | - Vera Lukashchuk
- Cobra Biologics, Stephenson Building, Keele Science Park, Keele ST5 5SP, UK
| | - Daniel C Smith
- Cobra Biologics, Stephenson Building, Keele Science Park, Keele ST5 5SP, UK
| | - Alan J Dickson
- Manchester Institute of Biotechnology, Faculty of Science and Engineering, Department of Chemical Engineering & Analytical Sciences, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
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18
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Perry C, Rayat ACME. Lentiviral Vector Bioprocessing. Viruses 2021; 13:268. [PMID: 33572347 PMCID: PMC7916122 DOI: 10.3390/v13020268] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/11/2022] Open
Abstract
Lentiviral vectors (LVs) are potent tools for the delivery of genes of interest into mammalian cells and are now commonly utilised within the growing field of cell and gene therapy for the treatment of monogenic diseases and adoptive therapies such as chimeric antigen T-cell (CAR-T) therapy. This is a comprehensive review of the individual bioprocess operations employed in LV production. We highlight the role of envelope proteins in vector design as well as their impact on the bioprocessing of lentiviral vectors. An overview of the current state of these operations provides opportunities for bioprocess discovery and improvement with emphasis on the considerations for optimal and scalable processing of LV during development and clinical production. Upstream culture for LV generation is described with comparisons on the different transfection methods and various bioreactors for suspension and adherent producer cell cultivation. The purification of LV is examined, evaluating different sequences of downstream process operations for both small- and large-scale production requirements. For scalable operations, a key focus is the development in chromatographic purification in addition to an in-depth examination of the application of tangential flow filtration. A summary of vector quantification and characterisation assays is also presented. Finally, the assessment of the whole bioprocess for LV production is discussed to benefit from the broader understanding of potential interactions of the different process options. This review is aimed to assist in the achievement of high quality, high concentration lentiviral vectors from robust and scalable processes.
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Affiliation(s)
- Christopher Perry
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Gower St, London WC1E 6BT, UK;
- Division of Advanced Therapies, National Institute for Biological Standards and Control, South Mimms EN6 3QG, UK
| | - Andrea C. M. E. Rayat
- The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, Gower St, London WC1E 6BT, UK;
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19
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Ho YY, Lu HK, Lim ZFS, Lim HW, Ho YS, Ng SK. Applications and analysis of hydrolysates in animal cell culture. BIORESOUR BIOPROCESS 2021; 8:93. [PMID: 34603939 PMCID: PMC8476327 DOI: 10.1186/s40643-021-00443-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 09/07/2021] [Indexed: 12/19/2022] Open
Abstract
Animal cells are used in the manufacturing of complex biotherapeutic products since the 1980s. From its initial uses in biological research to its current importance in the biopharmaceutical industry, many types of culture media were developed: from serum-based media to serum-free to protein-free chemically defined media. The cultivation of animal cells economically has become the ultimate goal in the field of biomanufacturing. Serum serves as a source of amino acids, lipids, proteins and most importantly growth factors and hormones, which are essential for many cell types. However, the use of serum is unfavorable due to its high price tag, increased lot-to-lot variations and potential risk of microbial contamination. Efforts are progressively being made to replace serum with recombinant proteins such as growth factors, cytokines and hormones, as well as supplementation with lipids, vitamins, trace elements and hydrolysates. While hydrolysates are more complex, they provide a diverse source of nutrients to animal cells, with potential beneficial effects beyond the nutritional value. In this review, we discuss the use of hydrolysates in animal cell culture and briefly cover the composition of hydrolysates, mode of action and potential contaminants with some perspectives on its potential role in animal cell culture media formulations in the future.
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Affiliation(s)
- Yin Ying Ho
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
| | - Hao Kim Lu
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
| | - Zhi Feng Sherman Lim
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
| | - Hao Wei Lim
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
| | - Ying Swan Ho
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
| | - Say Kong Ng
- grid.185448.40000 0004 0637 0221Bioprocessing Technology Institute, Agency for Science, Technology, and Research (A*STAR), 20 Biopolis Way, #06-01 Centros, Singapore, 138668 Singapore
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20
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Martínez-Molina E, Chocarro-Wrona C, Martínez-Moreno D, Marchal JA, Boulaiz H. Large-Scale Production of Lentiviral Vectors: Current Perspectives and Challenges. Pharmaceutics 2020; 12:pharmaceutics12111051. [PMID: 33153183 PMCID: PMC7693937 DOI: 10.3390/pharmaceutics12111051] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Revised: 10/20/2020] [Accepted: 10/31/2020] [Indexed: 02/07/2023] Open
Abstract
Lentiviral vectors (LVs) have gained value over recent years as gene carriers in gene therapy. These viral vectors are safer than what was previously being used for gene transfer and are capable of infecting both dividing and nondividing cells with a long-term expression. This characteristic makes LVs ideal for clinical research, as has been demonstrated with the approval of lentivirus-based gene therapies from the Food and Drug Administration and the European Agency for Medicine. A large number of functional lentiviral particles are required for clinical trials, and large-scale production has been challenging. Therefore, efforts are focused on solving the drawbacks associated with the production and purification of LVsunder current good manufacturing practice. In recent years, we have witnessed the development and optimization of new protocols, packaging cell lines, and culture devices that are very close to reaching the target production level. Here, we review the most recent, efficient, and promising methods for the clinical-scale production ofLVs.
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Affiliation(s)
- Eduardo Martínez-Molina
- Biopathology and Medicine Regenerative Institute (IBIMER), University of Granada (D.M.), 18016 Granada, Spain; (E.M.-M.); (C.C.-W.); (D.M.-M.); (J.A.M.)
- Department of Human Anatomy and Embryology, University of Granada, 18016 Granada, Spain
| | - Carlos Chocarro-Wrona
- Biopathology and Medicine Regenerative Institute (IBIMER), University of Granada (D.M.), 18016 Granada, Spain; (E.M.-M.); (C.C.-W.); (D.M.-M.); (J.A.M.)
- Department of Human Anatomy and Embryology, University of Granada, 18016 Granada, Spain
- Excellence Research Unit “Modeling Nature” (MNat), University of Granada, 18016 Granada, Spain
- Biosanitary Institute of Granada (ibs.GRANADA), SAS-Universidad de Granada, 18016 Granada, Spain
| | - Daniel Martínez-Moreno
- Biopathology and Medicine Regenerative Institute (IBIMER), University of Granada (D.M.), 18016 Granada, Spain; (E.M.-M.); (C.C.-W.); (D.M.-M.); (J.A.M.)
- Department of Human Anatomy and Embryology, University of Granada, 18016 Granada, Spain
- Excellence Research Unit “Modeling Nature” (MNat), University of Granada, 18016 Granada, Spain
- Biosanitary Institute of Granada (ibs.GRANADA), SAS-Universidad de Granada, 18016 Granada, Spain
| | - Juan A. Marchal
- Biopathology and Medicine Regenerative Institute (IBIMER), University of Granada (D.M.), 18016 Granada, Spain; (E.M.-M.); (C.C.-W.); (D.M.-M.); (J.A.M.)
- Department of Human Anatomy and Embryology, University of Granada, 18016 Granada, Spain
- Excellence Research Unit “Modeling Nature” (MNat), University of Granada, 18016 Granada, Spain
- Biosanitary Institute of Granada (ibs.GRANADA), SAS-Universidad de Granada, 18016 Granada, Spain
| | - Houria Boulaiz
- Biopathology and Medicine Regenerative Institute (IBIMER), University of Granada (D.M.), 18016 Granada, Spain; (E.M.-M.); (C.C.-W.); (D.M.-M.); (J.A.M.)
- Department of Human Anatomy and Embryology, University of Granada, 18016 Granada, Spain
- Excellence Research Unit “Modeling Nature” (MNat), University of Granada, 18016 Granada, Spain
- Biosanitary Institute of Granada (ibs.GRANADA), SAS-Universidad de Granada, 18016 Granada, Spain
- Correspondence: ; Tel.: +34-958-241-271
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Lu XA, He T, Han Z, Ding Y, Zhao L, Liu G, De Smet F, Huang X, Chen D, Qi F, Zhao X. Production of lentiviral vectors in suspension cells using low proportion of supercoiled circular plasmid DNA. Cytotechnology 2020; 72:10.1007/s10616-020-00433-4. [PMID: 33123933 PMCID: PMC7695760 DOI: 10.1007/s10616-020-00433-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 10/16/2020] [Indexed: 10/23/2022] Open
Abstract
The supercoiled circular (SC) topology form of plasmid DNA has been regarded to be advantageous over open circular or linearized analogue in transfection and expression efficiency, and therefore are largely demanded in the biopharmaceutical manufacturing. However, production of high-purity SC plasmid DNA would result in high manufacturing cost. The effect of SC proportion in plasmid DNA on the quality of packaged lentiviral vectors has never been reported. In this study, we established an efficient system for production of high-titer lentiviral vectors using suspension HEK293SF cells in serum-free media, and the lentiviral titer was not associated with the proportion of SC plasmid DNA. Plasmids DNA with different proportion of SC, open-circular, and linearized forms were prepared using the thermal denaturation method, and were transfected to adherent HEK293T or suspension HEK293SF cells for packaging of lentiviral vectors. The titer of lentiviral vectors from HEK293T cells, but not from HEK293SF cells, was significantly impaired when the proportion of SC plasmid DNA decreased from 60-80% to 30-40%. Further decrease of SC plasmid proportion to 3% led to a dramatic reduction of lentiviral titer no matter the packaging cell line was. However, lentiviral vectors from HEK293SF cells still showed a high titer even when the proportion of SC plasmid DNA was 3%. This study demonstrated that extremely high proportion of SC plasmid DNA was not required for packaging of high-titer lentiviral vector in HEK293SF cells, at least under our manufacturing process.
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Affiliation(s)
- Xin-An Lu
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Ting He
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Zhihai Han
- Department of Pulmonary and Critical Care Medicine, The Sixth Medical Center of PLA General Hospital, 100048, Beijing, China
| | - Yanping Ding
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Liang Zhao
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Guanghua Liu
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Floris De Smet
- Sartorius Stedim North America Inc., 565 Johnson Avenue, Bohemia, New York, 11716, USA
| | - Xiaojun Huang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, No. 11 South Street of Xizhimen, Xicheng District, 100044, Beijing, China
| | - Danqing Chen
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China
| | - Feifei Qi
- Immunochina Pharmaceuticals Co., Ltd, 100089, Beijing, China.
| | - Xiangyu Zhao
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, No. 11 South Street of Xizhimen, Xicheng District, 100044, Beijing, China.
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22
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Bae DH, Marino M, Iaffaldano B, Fenstermaker S, Afione S, Argaw T, McCright J, Kwilas A, Chiorini JA, Timmons AE, Reiser J. Design and Testing of Vector-Producing HEK293T Cells Bearing a Genomic Deletion of the SV40 T Antigen Coding Region. Mol Ther Methods Clin Dev 2020; 18:631-638. [PMID: 32775497 PMCID: PMC7397404 DOI: 10.1016/j.omtm.2020.07.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Accepted: 07/06/2020] [Indexed: 12/18/2022]
Abstract
The use of the human embryonic kidney (HEK) 293T cell line to manufacture vectors for in vivo applications raises safety concerns due to the presence of SV40 T antigen-encoding sequences. We used CRISPR-Cas9 genome editing to remove the SV40 T antigen-encoding sequences from HEK293T cells by transfecting them with a recombinant plasmid expressing Cas9 and two distinct single guide RNAs (sgRNAs) corresponding to the beginning and end of the T antigen coding region. Cell clones lacking T antigen-encoding sequences were identified using PCR. Whole-genome (WG) and targeted locus amplification (TLA) sequencing of the parental HEK293T cell line revealed multiple SV40 T antigen-encoding sequences replacing cellular sequences on chromosome 3. The putative T antigen null clones demonstrated a loss of sequence reads mapping to T antigen-encoding sequences. Western blot analysis of cell extracts prepared from the T antigen null clones confirmed that the SV40 large and small T antigen proteins were absent. Lentiviral vectors produced using the T antigen null clones exhibited titers up to 1.5 × 107 transducing units (TU)/mL, while the titers obtained from the parent HEK293T cell line were up to 4 × 107 TU/mL. The capacity of the T antigen-negative cells to produce high titer adeno-associated virus (AAV) vectors was also evaluated. The results obtained revealed that the lack of T antigen sequences did not impact AAV vector titers.
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Affiliation(s)
- Dahae Hailey Bae
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Michael Marino
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Brian Iaffaldano
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Sydney Fenstermaker
- Office of Biostatistics and Epidemiology, Center for Biologics Evaluation and Research, FDA, Silver Spring, MD, USA
| | - Sandra Afione
- AAV Biology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, USA
| | - Takele Argaw
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Jacob McCright
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Anna Kwilas
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - John A. Chiorini
- AAV Biology Section, National Institute of Dental and Craniofacial Research, NIH, Bethesda, MD, USA
| | - Andrew E. Timmons
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
| | - Jakob Reiser
- Division of Cellular and Gene Therapies, Center for Biologics Evaluation and Research, US Food and Drug Administration (FDA), Silver Spring, MD, USA
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