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Ward C, Beharry A, Tennakoon R, Rozik P, Wilhelm SDP, Heinemann IU, O’Donoghue P. Mechanisms and Delivery of tRNA Therapeutics. Chem Rev 2024; 124:7976-8008. [PMID: 38801719 PMCID: PMC11212642 DOI: 10.1021/acs.chemrev.4c00142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/11/2024] [Accepted: 04/26/2024] [Indexed: 05/29/2024]
Abstract
Transfer ribonucleic acid (tRNA) therapeutics will provide personalized and mutation specific medicines to treat human genetic diseases for which no cures currently exist. The tRNAs are a family of adaptor molecules that interpret the nucleic acid sequences in our genes into the amino acid sequences of proteins that dictate cell function. Humans encode more than 600 tRNA genes. Interestingly, even healthy individuals contain some mutant tRNAs that make mistakes. Missense suppressor tRNAs insert the wrong amino acid in proteins, and nonsense suppressor tRNAs read through premature stop signals to generate full length proteins. Mutations that underlie many human diseases, including neurodegenerative diseases, cancers, and diverse rare genetic disorders, result from missense or nonsense mutations. Thus, specific tRNA variants can be strategically deployed as therapeutic agents to correct genetic defects. We review the mechanisms of tRNA therapeutic activity, the nature of the therapeutic window for nonsense and missense suppression as well as wild-type tRNA supplementation. We discuss the challenges and promises of delivering tRNAs as synthetic RNAs or as gene therapies. Together, tRNA medicines will provide novel treatments for common and rare genetic diseases in humans.
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Affiliation(s)
- Cian Ward
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Aruun Beharry
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Rasangi Tennakoon
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Peter Rozik
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Sarah D. P. Wilhelm
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Ilka U. Heinemann
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Patrick O’Donoghue
- Department of Biochemistry, Department of Chemistry, The University of Western Ontario, London, Ontario N6A 5C1, Canada
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2
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Lemmens M, Dorsheimer L, Zeller A, Dietz-Baum Y. Non-clinical safety assessment of novel drug modalities: Genome safety perspectives on viral-, nuclease- and nucleotide-based gene therapies. MUTATION RESEARCH. GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2024; 896:503767. [PMID: 38821669 DOI: 10.1016/j.mrgentox.2024.503767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 04/08/2024] [Accepted: 05/13/2024] [Indexed: 06/02/2024]
Abstract
Gene therapies have emerged as promising treatments for various conditions including inherited diseases as well as cancer. Ensuring their safe clinical application requires the development of appropriate safety testing strategies. Several guidelines have been provided by health authorities to address these concerns. These guidelines state that non-clinical testing should be carried out on a case-by-case basis depending on the modality. This review focuses on the genome safety assessment of frequently used gene therapy modalities, namely Adeno Associated Viruses (AAVs), Lentiviruses, designer nucleases and mRNAs. Important safety considerations for these modalities, amongst others, are vector integrations into the patient genome (insertional mutagenesis) and off-target editing. Taking into account the constraints of in vivo studies, health authorities endorse the development of novel approach methodologies (NAMs), which are innovative in vitro strategies for genotoxicity testing. This review provides an overview of NAMs applied to viral and CRISPR/Cas9 safety, including next generation sequencing-based methods for integration site analysis and off-target editing. Additionally, NAMs to evaluate the oncogenicity risk arising from unwanted genomic modifications are discussed. Thus, a range of promising techniques are available to support the safe development of gene therapies. Thorough validation, comparisons and correlations with clinical outcomes are essential to identify the most reliable safety testing strategies. By providing a comprehensive overview of these NAMs, this review aims to contribute to a better understanding of the genome safety perspectives of gene therapies.
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Affiliation(s)
| | - Lena Dorsheimer
- Research and Development, Preclinical Safety, Sanofi, Industriepark Hoechst, Frankfurt am Main 65926, Germany.
| | - Andreas Zeller
- Pharmaceutical Sciences, pRED Innovation Center Basel, Hoffmann-La Roche Ltd, Basel 4070, Switzerland
| | - Yasmin Dietz-Baum
- Research and Development, Preclinical Safety, Sanofi, Industriepark Hoechst, Frankfurt am Main 65926, Germany
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3
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Minskaia E, Galieva A, Egorov AD, Ivanov R, Karabelsky A. Viral Vectors in Gene Replacement Therapy. BIOCHEMISTRY. BIOKHIMIIA 2023; 88:2157-2178. [PMID: 38462459 DOI: 10.1134/s0006297923120179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/29/2023] [Accepted: 10/17/2023] [Indexed: 03/12/2024]
Abstract
Throughout the years, several hundred million people with rare genetic disorders have been receiving only symptom management therapy. However, research and development efforts worldwide have led to the development of long-lasting, highly efficient, and safe gene therapy for a wide range of hereditary diseases. Improved viral vectors are now able to evade the preexisting immunity and more efficiently target and transduce therapeutically relevant cells, ensuring genome maintenance and expression of transgenes at the relevant levels. Hematological, ophthalmological, neurodegenerative, and metabolic therapeutic areas have witnessed successful treatment of hemophilia and muscular dystrophy, restoration of immune system in children with immunodeficiencies, and restoration of vision. This review focuses on three leading vector platforms of the past two decades: adeno-associated viruses (AAVs), adenoviruses (AdVs), and lentiviruses (LVs). Special attention is given to successful preclinical and clinical studies that have led to the approval of gene therapies: six AAV-based (Glybera® for lipoprotein lipase deficiency, Luxturna® for retinal dystrophy, Zolgensma® for spinal muscular atrophy, Upstaza® for AADC, Roctavian® for hemophilia A, and Hemgenix® for hemophilia B) and three LV-based (Libmeldy® for infantile metachromatic leukodystrophy, Zynteglo® for β-thalassemia, and Skysona® for ALD). The review also discusses the problems that arise in the development of gene therapy treatments, which, nevertheless, do not overshadow the successes of already developed gene therapies and the hope these treatments give to long-suffering patients and their families.
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Affiliation(s)
- Ekaterina Minskaia
- Scientific Center of Translational Medicine, Department of Gene Therapy, Sirius University of Science and Technology, Sochi, 354530, Russia.
| | - Alima Galieva
- Scientific Center of Translational Medicine, Department of Gene Therapy, Sirius University of Science and Technology, Sochi, 354530, Russia
| | - Alexander D Egorov
- Scientific Center of Translational Medicine, Department of Gene Therapy, Sirius University of Science and Technology, Sochi, 354530, Russia
| | - Roman Ivanov
- Scientific Center of Translational Medicine, Department of Gene Therapy, Sirius University of Science and Technology, Sochi, 354530, Russia
| | - Alexander Karabelsky
- Scientific Center of Translational Medicine, Department of Gene Therapy, Sirius University of Science and Technology, Sochi, 354530, Russia
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4
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Zhang M, Ehmann ME, Matukumalli S, Boob AG, Gilbert DM, Zhao H. SHIELD: a platform for high-throughput screening of barrier-type DNA elements in human cells. Nat Commun 2023; 14:5616. [PMID: 37699958 PMCID: PMC10497619 DOI: 10.1038/s41467-023-41468-3] [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: 10/06/2022] [Accepted: 09/04/2023] [Indexed: 09/14/2023] Open
Abstract
Chromatin boundary elements contribute to the partitioning of mammalian genomes into topological domains to regulate gene expression. Certain boundary elements are adopted as DNA insulators for safe and stable transgene expression in mammalian cells. These elements, however, are ill-defined and less characterized in the non-coding genome, partially due to the lack of a platform to readily evaluate boundary-associated activities of putative DNA sequences. Here we report SHIELD (Site-specific Heterochromatin Insertion of Elements at Lamina-associated Domains), a platform tailored for the high-throughput screening of barrier-type DNA elements in human cells. SHIELD takes advantage of the high specificity of serine integrase at heterochromatin, and exploits the natural heterochromatin spreading inside lamina-associated domains (LADs) for the discovery of potent barrier elements. We adopt SHIELD to evaluate the barrier activity of 1000 DNA elements in a high-throughput manner and identify 8 candidates with barrier activities comparable to the core region of cHS4 element in human HCT116 cells. We anticipate SHIELD could facilitate the discovery of novel barrier DNA elements from the non-coding genome in human cells.
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Affiliation(s)
- Meng Zhang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Mary Elisabeth Ehmann
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Srija Matukumalli
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - Aashutosh Girish Boob
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA
| | - David M Gilbert
- San Diego Biomedical Research Institute, San Diego, CA, 92121, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
- Department of Chemistry, Department of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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5
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Vats S, Ballesteros C, Hung S, Sparapani S, Wong K, Haruna J, Li C, Authier S. An Overview of Gene Editing Modalities and Related Non-clinical Testing Considerations. Int J Toxicol 2023; 42:207-218. [PMID: 36762691 DOI: 10.1177/10915818231153996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
Gene therapy has become an important modality for a wide range of therapeutic indications with a rapid increase in the number of therapeutic candidates being developed in this field. Understanding the molecular biology underlying the gene therapy is often critical to develop appropriate safety assessment strategies. We aimed to discuss some of the commonly used gene therapy modalities and common preclinical toxicology testing considerations when developing gene therapies. Non-viral gene delivery methods such as electroporation, microinjection, peptide nanoparticles and lipid nanoparticles are deployed as innovative molecular molecular construct which are included in the design of novel gene therapies and the associated molecular biology mechanisms have become relevant knowledge to non-clinical toxicology. Viral gene delivery methodologies including Adenovirus vectors, Adeno-Associated virus vectors and Lentivirus gene therapy vectors have also advanced considerably across numerous therapeutic areas, raising unique non-clinical toxicology and immunological considerations. General toxicology, biodistribution and tumorigenicity are the pillars of non-clinical safety testing in gene therapies. Evaluating the tumorigenicity potential of a gene editing therapy often leverages molecular pathology while some translational challenges remain. Toxicology study design is entering a new era where science-driven customized approaches and program specific considerations have become the norm.
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Affiliation(s)
- Srishti Vats
- 70294Charles River Laboratories, Laval, QC, Canada
| | | | - Selly Hung
- 70294Charles River Laboratories, Laval, QC, Canada
| | | | - Karen Wong
- 70294Charles River Laboratories, Laval, QC, Canada
| | | | - Christian Li
- 70294Charles River Laboratories, Laval, QC, Canada
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6
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Cabrera A, Edelstein HI, Glykofrydis F, Love KS, Palacios S, Tycko J, Zhang M, Lensch S, Shields CE, Livingston M, Weiss R, Zhao H, Haynes KA, Morsut L, Chen YY, Khalil AS, Wong WW, Collins JJ, Rosser SJ, Polizzi K, Elowitz MB, Fussenegger M, Hilton IB, Leonard JN, Bintu L, Galloway KE, Deans TL. The sound of silence: Transgene silencing in mammalian cell engineering. Cell Syst 2022; 13:950-973. [PMID: 36549273 PMCID: PMC9880859 DOI: 10.1016/j.cels.2022.11.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 09/22/2022] [Accepted: 11/22/2022] [Indexed: 12/24/2022]
Abstract
To elucidate principles operating in native biological systems and to develop novel biotechnologies, synthetic biology aims to build and integrate synthetic gene circuits within native transcriptional networks. The utility of synthetic gene circuits for cell engineering relies on the ability to control the expression of all constituent transgene components. Transgene silencing, defined as the loss of expression over time, persists as an obstacle for engineering primary cells and stem cells with transgenic cargos. In this review, we highlight the challenge that transgene silencing poses to the robust engineering of mammalian cells, outline potential molecular mechanisms of silencing, and present approaches for preventing transgene silencing. We conclude with a perspective identifying future research directions for improving the performance of synthetic gene circuits.
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Affiliation(s)
- Alan Cabrera
- Department of Bioengineering, Rice University, Houston, TX 77005, USA; Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hailey I Edelstein
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Fokion Glykofrydis
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Kasey S Love
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sebastian Palacios
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Josh Tycko
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Meng Zhang
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Sarah Lensch
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Cara E Shields
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Mark Livingston
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Ron Weiss
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Champaign, Urbana, IL 61801, USA
| | - Karmella A Haynes
- Wallace H. Coulter Department of Biomedical Engineering, Emory University, Atlanta, GA 30322, USA
| | - Leonardo Morsut
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA
| | - Yvonne Y Chen
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, Los Angeles, CA 90095, USA; Department of Chemical and Biomolecular Engineering, University of California, Los Angeles, Los Angeles, CA 90095, USA; Parker Institute for Cancer Immunotherapy Center at UCLA, Los Angeles, CA 90095, USA
| | - Ahmad S Khalil
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA
| | - Wilson W Wong
- Biological Design Center and Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - James J Collins
- Department of Stem Cell Biology and Regenerative Medicine, University of Southern California, Los Angeles, CA 90033-9080, USA; Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA, USA; Institute for Medical Engineering and Science, Massachusetts Institute of Technology, Cambridge, MA, USA; Harvard-MIT Program in Health Sciences and Technology, Cambridge, MA 02139, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA
| | - Susan J Rosser
- School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Karen Polizzi
- Department of Chemical Engineering, Imperial College London, South Kensington Campus, London, UK; Imperial College Centre for Synthetic Biology, South Kensington Campus, London, UK
| | - Michael B Elowitz
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Howard Hughes Medical Institute, California Institute of Technology, Pasadena, CA 91125, USA
| | - Martin Fussenegger
- Department of Biosystems Science and Engineering, ETH Zurich, Mattenstrasse 26, Basel 4058, Switzerland; Faculty of Science, University of Basel, Mattenstrasse 26, Basel 4058, Switzerland
| | - Isaac B Hilton
- Department of Bioengineering, Rice University, Houston, TX 77005, USA
| | - Joshua N Leonard
- Center for Synthetic Biology, Northwestern University, Evanston, IL 60208, USA; The Eli and Edythe Broad CIRM Center, Department of Chemical and Biological Engineering, Northwestern University, Evanston, IL 60208, USA
| | - Lacramioara Bintu
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
| | - Kate E Galloway
- Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tara L Deans
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA.
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7
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Cabriolu A, Odak A, Zamparo L, Yuan H, Leslie CS, Sadelain M. Globin vector regulatory elements are active in early hematopoietic progenitor cells. Mol Ther 2022; 30:2199-2209. [PMID: 35247584 PMCID: PMC9171148 DOI: 10.1016/j.ymthe.2022.02.028] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 02/23/2022] [Accepted: 02/28/2022] [Indexed: 01/19/2023] Open
Abstract
The globin genes are archetypal tissue-specific genes that are silent in most tissues but for late-stage erythroblasts upon terminal erythroid differentiation. The transcriptional activation of the β-globin gene is under the control of proximal and distal regulatory elements located on chromosome 11p15.4, including the β-globin locus control region (LCR). The incorporation of selected LCR elements in lentiviral vectors encoding β and β-like globin genes has enabled successful genetic treatment of the β-thalassemias and sickle cell disease. However, recent occurrences of benign clonal expansions in thalassemic patients and myelodysplastic syndrome in patients with sickle cell disease call attention to the non-erythroid functions of these powerful vectors. Here we demonstrate that lentivirally encoded LCR elements, in particular HS1 and HS2, can be activated in early hematopoietic cells including hematopoietic stem cells and myeloid progenitors. This activity is position-dependent and results in the transcriptional activation of a nearby reporter gene in these progenitor cell populations. We further show that flanking a globin vector with an insulator can effectively restrain this non-erythroid activity without impairing therapeutic globin expression. Globin lentiviral vectors harboring powerful LCR HS elements may thus expose to the risk of trans-activating cancer-related genes, which can be mitigated by a suitable insulator.
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Affiliation(s)
- Annalisa Cabriolu
- Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA
| | - Ashlesha Odak
- Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA; Weill Cornell Graduate School of Medical Sciences, Weill Cornell Medicine, 1300 York Ave., New York, NY 10065, USA
| | - Lee Zamparo
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA
| | - Han Yuan
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA
| | - Christina S Leslie
- Computational and Systems Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA
| | - Michel Sadelain
- Center for Cell Engineering, Memorial Sloan Kettering Cancer Center, 1250 1st Ave., New York, NY 10065, USA.
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8
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Abbasalipour M, Khosravi MA, Zeinali S, Khanahmad H, Azadmanesh K, Karimipoor M. Lentiviral vector containing beta-globin gene for beta thalassemia gene therapy. GENE REPORTS 2022. [DOI: 10.1016/j.genrep.2022.101615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Van Looveren D, Giacomazzi G, Thiry I, Sampaolesi M, Gijsbers R. Improved functionality and potency of next generation BinMLV viral vectors toward safer gene therapy. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2021; 23:51-67. [PMID: 34553002 PMCID: PMC8433069 DOI: 10.1016/j.omtm.2021.07.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 07/16/2021] [Indexed: 10/27/2022]
Abstract
To develop safer retroviral murine leukemia virus (MLV)-based vectors, we previously mutated and re-engineered the MLV integrase: the W390A mutation abolished the interaction with its cellular tethering factors, BET proteins, and a retargeting peptide (the chromodomain of the CBX1 protein) was fused C-terminally. The resulting BET-independent MLVW390A-CBX was shown to integrate efficiently and more randomly, away from typical retroviral markers. In this study, we assessed the functionality and stability of expression of the redistributed MLVW390A-CBX vector in more depth, and evaluated safety using a clinically more relevant vector design encompassing a self-inactivated (SIN) LTR and a weak internal elongation factor 1α short (EFS) promoter. MLVW390A-CBX-EFS produced like MLVWT and efficiently transduced laboratory cells and primary human CD34+ hematopoetic stem cells (HSC) without transgene silencing over time, while displaying a more preferred, redistributed, and safer integration pattern. In a human mesoangioblast (MAB) stem cell model, the myogenic fusion capacity was hindered following MLVWT transduction, while this remained unaffected when applying MLVW390A-CBX. Likewise, smooth muscle cell differentiation of MABs was unaltered by MLVW390A-CBX-EFS. Taken together, our results underscore the potential of MLVW390A-CBX-EFS as a clinically relevant viral vector for ex-vivo gene therapy, combining efficient production with a preferable integration site distribution profile and stable expression over time.
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Affiliation(s)
- Dominique Van Looveren
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Giorgia Giacomazzi
- Laboratory of Translational Cardiomyology, Department of Development and Regeneration, Stem Cell Research Institute, KU Leuven, 3000 Leuven, Belgium
| | - Irina Thiry
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Maurilio Sampaolesi
- Laboratory of Translational Cardiomyology, Department of Development and Regeneration, Stem Cell Research Institute, KU Leuven, 3000 Leuven, Belgium
| | - Rik Gijsbers
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmacological and Pharmaceutical Sciences, KU Leuven, 3000 Leuven, Belgium
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10
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Sertkaya H, Hidalgo L, Ficarelli M, Kmiec D, Signell AW, Ali S, Parker H, Wilson H, Neil SJ, Malim MH, Vink CA, Swanson CM. Minimal impact of ZAP on lentiviral vector production and transduction efficiency. Mol Ther Methods Clin Dev 2021; 23:147-157. [PMID: 34703838 PMCID: PMC8517000 DOI: 10.1016/j.omtm.2021.08.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 08/24/2021] [Indexed: 11/29/2022]
Abstract
The antiviral protein ZAP binds CpG dinucleotides in viral RNA to inhibit replication. This has likely led to the CpG suppression observed in many RNA viruses, including retroviruses. Sequences added to retroviral vector genomes, such as internal promoters, transgenes, or regulatory elements, substantially increase CpG abundance. Because these CpGs could allow retroviral vector RNA to be targeted by ZAP, we analyzed whether it restricts vector production, transduction efficiency, and transgene expression. Surprisingly, even though CpG-high HIV-1 was efficiently inhibited by ZAP in HEK293T cells, depleting ZAP did not substantially increase lentiviral vector titer using several packaging and genome plasmids. ZAP overexpression also did not inhibit lentiviral vector titer. In addition, decreasing CpG abundance in a lentiviral vector genome did not increase its titer, and a gammaretroviral vector derived from murine leukemia virus was not substantially restricted by ZAP. Overall, we show that the increased CpG abundance in retroviral vectors relative to the wild-type retroviruses they are derived from does not intrinsically sensitize them to ZAP. Further understanding of how ZAP specifically targets transcripts to inhibit their expression may allow the development of CpG sequence contexts that efficiently recruit or evade this antiviral system.
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Affiliation(s)
- Helin Sertkaya
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Laura Hidalgo
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Mattia Ficarelli
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Dorota Kmiec
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Adrian W. Signell
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Sadfer Ali
- Cell & Gene Therapy Platform, Medicinal Science and Technology, GSK, Stevenage SG1 2NY, UK
| | - Hannah Parker
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Harry Wilson
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Stuart J.D. Neil
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Michael H. Malim
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
| | - Conrad A. Vink
- Cell & Gene Therapy Platform, Medicinal Science and Technology, GSK, Stevenage SG1 2NY, UK
| | - Chad M. Swanson
- Department of Infectious Diseases, King’s College London, London SE1 9RT, UK
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11
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Papayanni PG, Psatha N, Christofi P, Li XG, Melo P, Volpin M, Montini E, Liu M, Kaltsounis G, Yiangou M, Emery DW, Anagnostopoulos A, Papayannopoulou T, Huang S, Stamatoyannopoulos G, Yannaki E. Investigating the Barrier Activity of Novel, Human Enhancer-Blocking Chromatin Insulators for Hematopoietic Stem Cell Gene Therapy. Hum Gene Ther 2021; 32:1186-1199. [PMID: 34477013 DOI: 10.1089/hum.2021.142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Despite the unequivocal success of hematopoietic stem and progenitor cell gene therapy, limitations still exist including genotoxicity and variegation/silencing of transgene expression. A class of DNA regulatory elements known as chromatin insulators (CIs) can mitigate both vector transcriptional silencing (barrier CIs) and vector-induced genotoxicity (enhancer-blocking CIs) and have been proposed as genetic modulators to minimize unwanted vector/genome interactions. Recently, a number of human, small-sized, and compact CIs bearing strong enhancer-blocking activity were identified. To ultimately uncover an ideal CI with a dual, enhancer-blocking and barrier activity, we interrogated these elements in vitro and in vivo. After initial screening of a series of these enhancer-blocking insulators for potential barrier activity, we identified three distinct categories with no, partial, or full protection against transgene silencing. Subsequently, the two CIs with full barrier activity (B4 and C1) were tested for their ability to protect against position effects in primary cells, after incorporation into lentiviral vectors (LVs) and transduction of human CD34+ cells. B4 and C1 did not adversely affect vector titers due to their small size, while they performed as strong barrier insulators in CD34+ cells, both in vitro and in vivo, shielding transgene's long-term expression, more robustly when placed in the forward orientation. Overall, the incorporation of these dual-functioning elements into therapeutic viral vectors will potentially provide a new generation of safer and more efficient LVs for all hematopoietic stem cell gene therapy applications.
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Affiliation(s)
- Penelope-Georgia Papayanni
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece.,Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikoletta Psatha
- Altius Institute for Biomedical Sciences, Seattle, Washington, USA
| | - Panayota Christofi
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece.,Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Xing-Guo Li
- Graduate Institute of Biomedical Sciences, China Medical University, Taichung, Taiwan
| | - Pamela Melo
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece.,Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Monica Volpin
- San Raffaele Telethon Institute for Gene Therapy-IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Eugenio Montini
- San Raffaele Telethon Institute for Gene Therapy-IRCCS Ospedale San Raffaele Scientific Institute, Milan, Italy
| | - Mingdong Liu
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Georgios Kaltsounis
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece
| | - Minas Yiangou
- Department of Genetics, Development and Molecular Biology, School of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - David W Emery
- Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Achilles Anagnostopoulos
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece
| | | | - Suming Huang
- Department of Pediatrics, Pennsylvania State University College of Medicine, Hershey, Pennsylvania, USA
| | | | - Evangelia Yannaki
- Hematopoietic Cell Transplantation Unit, Hematology Department, Gene and Cell Therapy Center, "George Papanikolaou" Hospital, Thessaloniki, Greece.,Department of Medicine, University of Washington, Seattle, Washington, USA
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12
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Taher AT, Cappellini MD. Luspatercept for β-thalassemia: beyond red blood cell transfusions. Expert Opin Biol Ther 2021; 21:1363-1371. [PMID: 34404288 DOI: 10.1080/14712598.2021.1968825] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
INTRODUCTION Red blood cell transfusions and iron chelation therapy are the cornerstone of treatment for β-thalassemia, with allogeneic hematopoietic stem cell transplantation and gene therapy offering further disease-management options for eligible patients. With up to 90% of severe cases of β-thalassemia occurring in resource-constrained countries, and estimates indicating that 22,500 deaths occur annually as a direct consequence of undertransfusion, provision of adequate treatment remains a major issue. AREAS COVERED In this review, we provide an overview of luspatercept, a first-in-class erythroid maturation agent, and present the available clinical data related to the treatment of β-thalassemia. EXPERT OPINION The recent approval of luspatercept offers a new, long-term therapeutic option for adult patients with transfusion-dependent β-thalassemia to reduce red blood cell transfusion burden, anemia, and iron overload.
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Affiliation(s)
- Ali T Taher
- Department of Internal Medicine, American University of Beirut Medical Center, Beirut, Lebanon
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13
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Bulcha JT, Wang Y, Ma H, Tai PWL, Gao G. Viral vector platforms within the gene therapy landscape. Signal Transduct Target Ther 2021; 6:53. [PMID: 33558455 PMCID: PMC7868676 DOI: 10.1038/s41392-021-00487-6] [Citation(s) in RCA: 497] [Impact Index Per Article: 165.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 10/05/2020] [Accepted: 10/23/2020] [Indexed: 01/30/2023] Open
Abstract
Throughout its 40-year history, the field of gene therapy has been marked by many transitions. It has seen great strides in combating human disease, has given hope to patients and families with limited treatment options, but has also been subject to many setbacks. Treatment of patients with this class of investigational drugs has resulted in severe adverse effects and, even in rare cases, death. At the heart of this dichotomous field are the viral-based vectors, the delivery vehicles that have allowed researchers and clinicians to develop powerful drug platforms, and have radically changed the face of medicine. Within the past 5 years, the gene therapy field has seen a wave of drugs based on viral vectors that have gained regulatory approval that come in a variety of designs and purposes. These modalities range from vector-based cancer therapies, to treating monogenic diseases with life-altering outcomes. At present, the three key vector strategies are based on adenoviruses, adeno-associated viruses, and lentiviruses. They have led the way in preclinical and clinical successes in the past two decades. However, despite these successes, many challenges still limit these approaches from attaining their full potential. To review the viral vector-based gene therapy landscape, we focus on these three highly regarded vector platforms and describe mechanisms of action and their roles in treating human disease.
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Affiliation(s)
- Jote T Bulcha
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA
| | - Yi Wang
- Department of Pathophysiology, West China College of Basic medical sciences & Forensic Medicine, Sichuan University, Chengdu, China
| | - Hong Ma
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA
| | - Phillip W L Tai
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
- VIDE Program, University of Massachusetts Medical School, Worcester, MA, USA.
| | - Guangping Gao
- Horae Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA, USA.
- Department of Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, MA, USA.
- Li Weibo Institute for Rare Diseases Research, University of Massachusetts Medical School, Worcester, MA, USA.
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14
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Zimak J, Wagoner ZW, Nelson N, Waechtler B, Schlosser H, Kopecky M, Wu J, Zhao W. Epigenetic silencing directs expression heterogeneity of stably integrated multi-transcript unit genetic circuits. Sci Rep 2021; 11:2424. [PMID: 33510302 PMCID: PMC7844226 DOI: 10.1038/s41598-021-81975-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 01/08/2021] [Indexed: 12/19/2022] Open
Abstract
We report that epigenetic silencing causes the loss of function of multi-transcript unit constructs that are integrated using CRISPR-Cas9. Using a modular two color reporter system flanked by selection markers, we demonstrate that expression heterogeneity does not correlate with sequence alteration but instead correlates with chromosomal accessibility. We partially reverse this epigenetic silencing via small-molecule inhibitors of methylation and histone deacetylation. We then correlate each heterogeneously-expressing phenotype with its expected epigenetic state by employing ATAC-seq. The stability of each expression phenotype is reinforced by selective pressure, which indicates that ongoing epigenetic remodeling can occur for over one month after integration. Collectively, our data suggests that epigenetic silencing limits the utility of multi-transcript unit constructs that are integrated via double-strand repair pathways. Our research implies that mammalian synthetic biologists should consider localized epigenetic outcomes when designing complex genetic circuits.
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Affiliation(s)
- Jan Zimak
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Zachary W Wagoner
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Nellie Nelson
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Brooke Waechtler
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Hana Schlosser
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Morgan Kopecky
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA
| | - Jie Wu
- Chao Family Comprehensive Cancer Center, University of California, Irvine, Irvine, CA, 92697, USA.,Department of Biological Chemistry, University of California, Irvine, Irvine, CA, 92697, USA
| | - Weian Zhao
- Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, Irvine, CA, 92697, USA. .,Department of Pharmaceutical Sciences, University of California, Irvine, Irvine, CA, 92697, USA. .,Chao Family Comprehensive Cancer Center, University of California, Irvine, Irvine, CA, 92697, USA. .,Edwards Life Sciences Center for Advanced Cardiovascular Technology, University of California, Irvine, Irvine, CA, 92697, USA. .,Department of Biomedical Engineering, University of California, Irvine, Irvine, CA, 92697, USA. .,Department of Biological Chemistry, University of California, Irvine, Irvine, CA, 92697, USA.
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15
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Thenmozhi R, Lee JS, Park NY, Choi BO, Hong YB. Gene Therapy Options as New Treatment for Inherited Peripheral Neuropathy. Exp Neurobiol 2020; 29:177-188. [PMID: 32624504 PMCID: PMC7344374 DOI: 10.5607/en20004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 04/21/2020] [Accepted: 05/11/2020] [Indexed: 02/06/2023] Open
Abstract
Inherited peripheral neuropathy (IPN) is caused by heterogeneous genetic mutations in more than 100 genes. So far, several treatment options for IPN have been developed and clinically evaluated using small molecules. However, gene therapy-based therapeutic strategies have not been aggressively investigated, likely due to the complexities of inheritance in IPN. Indeed, because the majority of the causative mutations of IPN lead to gain-of-function rather than loss-of-function, developing a therapeutic strategy is more difficult, especially considering gene therapy for genetic diseases began with the simple idea of replacing a defective gene with a functional copy. Recent advances in gene manipulation technology have brought novel approaches to gene therapy and its clinical application for IPN treatment. For example, in addition to the classically used gene replacement for mutant genes in recessively inherited IPN, other techniques including gene addition to modify the disease phenotype, modulations of target gene expression, and techniques to edit mutant genes have been developed and evaluated as potent therapeutic strategies for dominantly inherited IPN. In this review, the current status of gene therapy for IPN and future perspectives will be discussed.
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Affiliation(s)
| | - Ji-Su Lee
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea
| | - Na Young Park
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
| | - Byung-Ok Choi
- Stem Cell & Regenerative Medicne Institute, Samsung Medical Center, Seoul 06351, Korea.,Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.,Department of Health Sciences and Technology, SAIHST, Sungkyunkwan University, Seoul 06351, Korea
| | - Young Bin Hong
- Department of Biochemistry, College of Medicine, Dong-A University, Busan 49201, Korea
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16
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Lu XB, Guo YH, Huang W. Characterization of the cHS4 insulator in mouse embryonic stem cells. FEBS Open Bio 2020; 10:644-656. [PMID: 32087050 PMCID: PMC7137798 DOI: 10.1002/2211-5463.12818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2019] [Revised: 02/09/2020] [Accepted: 02/21/2020] [Indexed: 01/16/2023] Open
Abstract
Synthetic biology circuits are often constructed with multiple gene expression units assembled in close proximity, and they can be used to perform complex functions in embryonic stem cells (ESCs). However, mutual interference between transcriptional units has not been well studied in mouse ESCs. To assess the efficiency of insulators at suppressing promoter interference in mouse ESCs, we used an evaluation scheme in which a tunable tetracycline response element promoter is connected to a constant Nanog promoter. The chicken hypersensitive site 4 (cHS4) insulator, widely used both for enhancer blocking and for barrier insulation in vitro and in vivo, was positioned between the two expression units for assessment. By inserting the cassette into various loci of the mouse ESC genome with PiggyBac transposon, we were able to quantitatively examine the protective effect of cHS4 by gradually increasing the transcriptional activity of the tetracycline response element promoter with doxycycline and then measuring the transcriptional activity of the Nanog promoter. Our results indicate that the cHS4 insulator has minimal insulating effects on promoter interference in mouse ESCs. Further studies show that the cHS4 insulation effect may be promoter specific and related to interaction with CCCTC‐binding factor‐mediated loop formation. In addition, we also compared DNA transposition and transgene expression with or without the cHS4 insulator using well‐established ESC reporters. The results indicate that cHS4 has no apparent effects on DNA transposition and transgene expression levels, but exerts modest protective effects on long‐term transgene silencing.
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Affiliation(s)
- Xi-Bin Lu
- Core Research Facilities, Southern University of Science and Technology, Shenzhen, China
| | - Yu-Han Guo
- Forward Pharmaceuticals Limited Co., Shenzhen, China
| | - Wei Huang
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
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17
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Leonard A, Tisdale J, Abraham A. Curative options for sickle cell disease: haploidentical stem cell transplantation or gene therapy? Br J Haematol 2020; 189:408-423. [PMID: 32034776 DOI: 10.1111/bjh.16437] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Haematopoietic stem cell transplantation (HSCT) is curative in sickle cell disease (SCD); however, the lack of available matched donors makes this therapy out of reach for the majority of patients with SCD. Alternative donor sources such as haploidentical HSCT expand the donor pool to nearly all patients with SCD, with recent data showing high overall survival, limited toxicities, and effective reduction in acute and chronic graft-versus-host disease (GVHD). Simultaneously, multiple gene therapy strategies are entering clinical trials with preliminary data showing their success, theoretically offering all patients yet another curative strategy without the morbidity and mortality of GVHD. As improvements are made for alternative donors in the allogeneic setting and as data emerge from gene therapy trials, the optimal curative strategy for any individual patient with SCD will be determined by many critical factors including efficacy, transplant morbidity and mortality, safety, patient disease status and preference, cost and applicability. Haploidentical may be the preferred choice now based mostly on availability of data; however, gene therapy is closing the gap and may ultimately prove to be the better option. Progress in both strategies, however, makes cure more attainable for the individual with SCD.
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Affiliation(s)
- Alexis Leonard
- Cellular and Molecular Therapeutics Branch, National Heart, Lung, and Blood Institute (NHLBI) and National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA.,Division of Hematology, Center for Cancer and Blood Disorders, Children's National Health System, Washington, DC, USA.,Blood and Marrow Transplantation, Center for Cancer and Blood Disorders, Children's National Health System, Washington, DC, USA
| | - John Tisdale
- Cellular and Molecular Therapeutics Branch, National Heart, Lung, and Blood Institute (NHLBI) and National Institute of Diabetes, Digestive, and Kidney Diseases (NIDDK), National Institutes of Health, Bethesda, MD, USA
| | - Allistair Abraham
- Blood and Marrow Transplantation, Center for Cancer and Blood Disorders, Children's National Health System, Washington, DC, USA
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18
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Harbottle JA, Petrie L, Ruhe M, Houssen WE, Jaspars M, Kolb AF. A cell-based assay system for activators of the environmental cell stress response. Anal Biochem 2020; 592:113583. [PMID: 31945311 DOI: 10.1016/j.ab.2020.113583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/31/2019] [Accepted: 01/11/2020] [Indexed: 12/23/2022]
Abstract
Improved health span and lifespan extension in a wide phylogenetic range of species is associated with the induction of the environmental cell stress response through a signalling pathway regulated by the transcription factor Nrf2. Phytochemicals which stimulate this response may form part of therapeutic interventions which stimulate endogenous cytoprotective mechanisms, thereby delaying the onset of age-related diseases and promoting healthy ageing in humans. In order to identify compounds that activate the Nrf2 pathway, a cell-based reporter system was established in HepG2 cells using a luciferase reporter gene under the control of the Nqo1 promoter. Sulforaphane, an isothiocyanate derived from cruciferous vegetables and a known activator of the Nrf2 pathway, was used to validate the reporter system. The transfected cell line HepG2 C1 was subsequently used to screen natural product libraries. Five compounds were identified as activating the bioluminescent reporter by greater than 5-fold. The two most potent compounds, MBC20 and MBC37, were further characterised and shown to stimulate endogenous cytoprotective gene and protein expression. The bioluminescent reporter system will allow rapid, in vitro identification of novel compounds that have the potential to improve health span through activation of the environmental stress response.
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Affiliation(s)
| | - Linda Petrie
- Metabolic Health Group, Obesity & Metabolic Health Theme, Rowett Institute, UK
| | - Madeleine Ruhe
- Metabolic Health Group, Obesity & Metabolic Health Theme, Rowett Institute, UK
| | - Wael E Houssen
- Marine Biodiscovery Centre, Chemistry Department, University of Aberdeen, Aberdeen, AB24 3UE, Scotland, UK; Institute of Medical Sciences, University of Aberdeen, Aberdeen, AB25 2ZD, Scotland, UK
| | - Marcel Jaspars
- Marine Biodiscovery Centre, Chemistry Department, University of Aberdeen, Aberdeen, AB24 3UE, Scotland, UK
| | - Andreas F Kolb
- Metabolic Health Group, Obesity & Metabolic Health Theme, Rowett Institute, UK.
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19
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Karponi G, Zogas N. Gene Therapy For Beta-Thalassemia: Updated Perspectives. APPLICATION OF CLINICAL GENETICS 2019; 12:167-180. [PMID: 31576160 PMCID: PMC6765258 DOI: 10.2147/tacg.s178546] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/11/2019] [Indexed: 12/26/2022]
Abstract
Allogeneic hematopoietic stem cell transplantation was until very recently, the only permanent curative option available for patients suffering from transfusion-dependent beta-thalassemia. Gene therapy, by autologous transplantation of genetically modified hematopoietic stem cells, currently represents a novel therapeutic promise, after many years of extensive preclinical research for the optimization of gene transfer protocols. Nowadays, clinical trials being held on a worldwide setting, have demonstrated that, by re-establishing effective hemoglobin production, patients may be rendered transfusion- and chelation-independent and evade the immunological complications that normally accompany allogeneic hematopoietic stem cell transplantation. The present review will offer a retrospective scope of the long way paved towards successful implementation of gene therapy for beta-thalassemia, and will pinpoint the latest strategies employed to increase globin expression that extend beyond the classic transgene addition perspective. A thorough search was performed using Pubmed in order to identify studies that provide a proof of principle on the aforementioned topic at a preclinical and clinical level. Inclusion criteria also regarded gene transfer technologies of the past two decades, as well as publications outlining the pitfalls that precluded earlier successful implementation of gene therapy for beta-thalassemia. Overall, after decades of research, that included both successes and pitfalls, the path towards a permanent, donor-irrespective cure for beta-thalassemia patients is steadily becoming a realistic approach.
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Affiliation(s)
- Garyfalia Karponi
- Department of Veterinary Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Nikolaos Zogas
- Department of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
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20
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Ingusci S, Verlengia G, Soukupova M, Zucchini S, Simonato M. Gene Therapy Tools for Brain Diseases. Front Pharmacol 2019; 10:724. [PMID: 31312139 PMCID: PMC6613496 DOI: 10.3389/fphar.2019.00724] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 06/05/2019] [Indexed: 01/20/2023] Open
Abstract
Neurological disorders affecting the central nervous system (CNS) are still incompletely understood. Many of these disorders lack a cure and are seeking more specific and effective treatments. In fact, in spite of advancements in knowledge of the CNS function, the treatment of neurological disorders with modern medical and surgical approaches remains difficult for many reasons, such as the complexity of the CNS, the limited regenerative capacity of the tissue, and the difficulty in conveying conventional drugs to the organ due to the blood-brain barrier. Gene therapy, allowing the delivery of genetic materials that encodes potential therapeutic molecules, represents an attractive option. Gene therapy can result in a stable or inducible expression of transgene(s), and can allow a nearly specific expression in target cells. In this review, we will discuss the most commonly used tools for the delivery of genetic material in the CNS, including viral and non-viral vectors; their main applications; their advantages and disadvantages. We will discuss mechanisms of genetic regulation through cell-specific and inducible promoters, which allow to express gene products only in specific cells and to control their transcriptional activation. In addition, we will describe the applications to CNS diseases of post-transcriptional regulation systems (RNA interference); of systems allowing spatial or temporal control of expression [optogenetics and Designer Receptors Exclusively Activated by Designer Drugs (DREADDs)]; and of gene editing technologies (CRISPR/Cas9, Zinc finger proteins). Particular attention will be reserved to viral vectors derived from herpes simplex type 1, a potential tool for the delivery and expression of multiple transgene cassettes simultaneously.
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Affiliation(s)
- Selene Ingusci
- Department of Medical Sciences and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy
| | - Gianluca Verlengia
- Department of Medical Sciences and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy.,Division of Neuroscience, University Vita-Salute San Raffaele, Milan, Italy
| | - Marie Soukupova
- Department of Medical Sciences and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy
| | - Silvia Zucchini
- Department of Medical Sciences and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy.,Technopole of Ferrara, LTTA Laboratory for Advanced Therapies, Ferrara, Italy
| | - Michele Simonato
- Department of Medical Sciences and National Institute of Neuroscience, University of Ferrara, Ferrara, Italy.,Division of Neuroscience, University Vita-Salute San Raffaele, Milan, Italy
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21
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Fernández-Chacón M, Casquero-García V, Luo W, Francesca Lunella F, Ferreira Rocha S, Del Olmo-Cabrera S, Benedito R. iSuRe-Cre is a genetic tool to reliably induce and report Cre-dependent genetic modifications. Nat Commun 2019; 10:2262. [PMID: 31118412 PMCID: PMC6531465 DOI: 10.1038/s41467-019-10239-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 04/23/2019] [Indexed: 01/09/2023] Open
Abstract
Most biomedical research aimed at understanding gene function uses the Cre-Lox system, which consists of the Cre recombinase-dependent deletion of genes containing LoxP sites. This system enables conditional genetic modifications because the expression and activity of the recombinase Cre/CreERT2 can be regulated in space by tissue-specific promoters and in time by the ligand tamoxifen. Since the precise Cre-Lox recombination event is invisible, methods were developed to report Cre activity and are widely used. However, numerous studies have shown that expression of a given Cre activity reporter cannot be assumed to indicate deletion of other LoxP-flanked genes of interest. Here, we report the generation of an inducible dual reporter-Cre mouse allele, iSuRe-Cre. By significantly increasing Cre activity in reporter-expressing cells, iSuRe-Cre provides certainty that these cells have completely recombined floxed alleles. This genetic tool increases the ease, efficiency, and reliability of conditional mutagenesis and gene function analysis.
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Affiliation(s)
- Macarena Fernández-Chacón
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Verónica Casquero-García
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Wen Luo
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Federica Francesca Lunella
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Susana Ferreira Rocha
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Sergio Del Olmo-Cabrera
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain
| | - Rui Benedito
- Molecular Genetics of Angiogenesis Group, Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, E28029, Spain.
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22
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Rozov SM, Deineko EV. Strategies for Optimizing Recombinant Protein Synthesis in Plant Cells: Classical Approaches and New Directions. Mol Biol 2019. [DOI: 10.1134/s0026893319020146] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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23
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Cellular Antisilencing Elements Support Transgene Expression from Herpes Simplex Virus Vectors in the Absence of Immediate Early Gene Expression. J Virol 2018; 92:JVI.00536-18. [PMID: 29950408 DOI: 10.1128/jvi.00536-18] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 06/13/2018] [Indexed: 01/22/2023] Open
Abstract
Inactivation of all herpes simplex virus (HSV) immediate early (IE) genes to eliminate vector cytotoxicity results in rapid silencing of the viral genome, similar to the establishment of HSV latency. We recently reported that silencing of a nonviral reporter cassette could be overcome in nonneuronal cells by positioning the cassette in the viral latency (LAT) locus between resident chromatin boundary elements. Here, we tested the abilities of the chicken hypersensitive site 4 insulator and the human ubiquitous chromatin opening element A2UCOE to promote transgene expression from an IE-gene-inactivated HSV vector. We found that A2UCOE was particularly active in nonneuronal cells and reduced reporter promoter occupancy by a repressive histone mark. We determined whether multiple transgenes could be expressed under the control of different promoters from different loci of the same virus. The results showed abundant coexpression of LAT-embedded and A2UCOE-flanked genes in nonneuronal cells. In addition, a third reporter gene without known protective elements was active in cultured rat sensory neurons. These findings indicate that cellular antisilencing sequences can contribute to the expression of multiple genes from separate promoters in fully IE gene-disabled HSV vectors, providing an opportunity for therapeutic applications requiring mutually independent expression of different gene products from a single vector.IMPORTANCE Gene therapy has now entered a phase of development in which a growing number of recessive single gene defects can be successfully treated by vector-mediated introduction of a wild-type copy of the gene into the appropriate tissue. However, many disease conditions, such as neurodegeneration, cancer, and inflammatory processes, are more complex, requiring either multiple gene corrections or provision of coordinated gene activities to achieve a therapeutic outcome. Although herpes simplex virus (HSV) vectors have the capacity to meet this need, the challenge has been to genetically engineer the HSV genome in a manner to prevent expression of any viral genes while retaining the ability to express multiple therapeutic transgenes under independent transcriptional control. Here, we show that non-HSV insulator elements can be applied to retain at least transient transgene activity from multiple viral loci, thereby opening the door for more complex gene therapy applications in the future.
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Cavalieri V, Baiamonte E, Lo Iacono M. Non-Primate Lentiviral Vectors and Their Applications in Gene Therapy for Ocular Disorders. Viruses 2018; 10:E316. [PMID: 29890733 PMCID: PMC6024700 DOI: 10.3390/v10060316] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 06/06/2018] [Accepted: 06/07/2018] [Indexed: 12/18/2022] Open
Abstract
Lentiviruses have a number of molecular features in common, starting with the ability to integrate their genetic material into the genome of non-dividing infected cells. A peculiar property of non-primate lentiviruses consists in their incapability to infect and induce diseases in humans, thus providing the main rationale for deriving biologically safe lentiviral vectors for gene therapy applications. In this review, we first give an overview of non-primate lentiviruses, highlighting their common and distinctive molecular characteristics together with key concepts in the molecular biology of lentiviruses. We next examine the bioengineering strategies leading to the conversion of lentiviruses into recombinant lentiviral vectors, discussing their potential clinical applications in ophthalmological research. Finally, we highlight the invaluable role of animal organisms, including the emerging zebrafish model, in ocular gene therapy based on non-primate lentiviral vectors and in ophthalmology research and vision science in general.
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Affiliation(s)
- Vincenzo Cavalieri
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, Viale delle Scienze Edificio 16, 90128 Palermo, Italy.
- Advanced Technologies Network (ATeN) Center, University of Palermo, Viale delle Scienze Edificio 18, 90128 Palermo, Italy.
| | - Elena Baiamonte
- Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital, 90146 Palermo, Italy.
| | - Melania Lo Iacono
- Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital, 90146 Palermo, Italy.
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25
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Yuen G, Khan FJ, Gao S, Stommel JM, Batchelor E, Wu X, Luo J. CRISPR/Cas9-mediated gene knockout is insensitive to target copy number but is dependent on guide RNA potency and Cas9/sgRNA threshold expression level. Nucleic Acids Res 2017; 45:12039-12053. [PMID: 29036671 PMCID: PMC5714203 DOI: 10.1093/nar/gkx843] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 09/11/2017] [Accepted: 09/13/2017] [Indexed: 12/26/2022] Open
Abstract
CRISPR/Cas9 is a powerful gene editing tool for gene knockout studies and functional genomic screens. Successful implementation of CRISPR often requires Cas9 to elicit efficient target knockout in a population of cells. In this study, we investigated the role of several key factors, including variation in target copy number, inherent potency of sgRNA guides, and expression level of Cas9 and sgRNA, in determining CRISPR knockout efficiency. Using isogenic, clonal cell lines with variable copy numbers of an EGFP transgene, we discovered that CRISPR knockout is relatively insensitive to target copy number, but is highly dependent on the potency of the sgRNA guide sequence. Kinetic analysis revealed that most target mutation occurs between 5 and 10 days following Cas9/sgRNA transduction, while sgRNAs with different potencies differ by their knockout time course and by their terminal-phase knockout efficiency. We showed that prolonged, low level expression of Cas9 and sgRNA often fails to elicit target mutation, particularly if the potency of the sgRNA is also low. Our findings provide new insights into the behavior of CRISPR/Cas9 in mammalian cells that could be used for future improvement of this platform.
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Affiliation(s)
- Garmen Yuen
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Fehad J. Khan
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
- Undergraduate Scholarship Program, National Institutes of Health, Bethesda, MD, USA
| | - Shaojian Gao
- Thoracic and Gastrointestinal Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Jayne M. Stommel
- Radiation Oncology Branch, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Eric Batchelor
- Laboratory of Pathology, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Xiaolin Wu
- Cancer Research Technology Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Ji Luo
- Laboratory of Cancer Biology and Genetics, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
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26
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Morgan RA, Gray D, Lomova A, Kohn DB. Hematopoietic Stem Cell Gene Therapy: Progress and Lessons Learned. Cell Stem Cell 2017; 21:574-590. [PMID: 29100011 PMCID: PMC6039108 DOI: 10.1016/j.stem.2017.10.010] [Citation(s) in RCA: 153] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The use of allogeneic hematopoietic stem cells (HSCs) to treat genetic blood cell diseases has become a clinical standard but is limited by the availability of suitable matched donors and potential immunologic complications. Gene therapy using autologous HSCs should avoid these limitations and thus may be safer. Progressive improvements in techniques for genetic correction of HSCs, by either vector gene addition or gene editing, are facilitating successful treatments for an increasing number of diseases. We highlight the progress, successes, and remaining challenges toward the development of HSC gene therapies and discuss lessons they provide for the development of future clinical stem cell therapies.
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Affiliation(s)
- Richard A Morgan
- Charles R. Drew University of Medicine and Science, Los Angeles, CA, 90059; Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095
| | - David Gray
- Molecular Biology Institute Interdepartmental Doctoral Program, University of California, Los Angeles, CA, 90095
| | - Anastasia Lomova
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095
| | - Donald B Kohn
- Department of Molecular and Medical Pharmacology, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095; Department of Microbiology, Immunology & Molecular Genetics, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095; Department of Pediatrics, David Geffen School of Medicine at University of California, Los Angeles, CA, 90095; The Eli & Edythe Broad Center of Regenerative Medicine & Stem Cell Research, University of California, Los Angeles, CA, USA.
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27
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Li Q, Wang W, Guo X, Jia YL, Wang YF, Wang TY. A short synthetic chimeric sequence harboring matrix attachment region/PSAR2 increases transgene expression in Chinese hamster ovary cells. Biosci Biotechnol Biochem 2017; 81:1755-1761. [DOI: 10.1080/09168451.2017.1350563] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Abstract
A chimeric DNA fragment containing an interferon-beta matrix attachment region (MAR) and an immunoglobulin MAR (PSAR2) was synthesized. PSAR2 was cloned into the upstream or downstream region of an enhanced green fluorescent protein (eGFP) expression cassette in a eukaryotic vector, which was then transfected into CHO cells. The results showed that PSAR2 did not effectively increase transgene expression when it was cloned into the upstream region of the eGFP expression cassette. However, when inserted downstream of the eGFP expression cassette, PSAR2-enhanced transient transgene expression and significantly increased the numbers of stably transfected cells compared with the control vector. Additionally, PSAR2 significantly increased eGFP copy numbers as compared with the control vector. PSAR2 could significantly enhance transgene expression in CHO cells according to the position in the vector and increased transgene copy numbers. We found a short chimeric sequence harboring two MARs effectively increased transgene expression in CHO cells.
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Affiliation(s)
- Qin Li
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
| | - Wen Wang
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Xiao Guo
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Yan-Fang Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
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28
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Scholz SJ, Fronza R, Bartholomä CC, Cesana D, Montini E, von Kalle C, Gil-Farina I, Schmidt M. Lentiviral Vector Promoter is Decisive for Aberrant Transcript Formation. Hum Gene Ther 2017; 28:875-885. [PMID: 28825370 DOI: 10.1089/hum.2017.162] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Lentiviral vectors hold great promise for the genetic correction of various inherited diseases. However, lentiviral vector biology is still not completely understood and warrants the precise decoding of molecular mechanisms underlying integration and post-translational modification. This study investigated a series of self-inactivating (SIN) and full long terminal repeat (LTR) lentiviral vectors that contained different types of promoters with or without a transgene to gain deeper insights in lentiviral target site selection and potential perturbation of cellular gene expression. Using an optimized nonrestrictive linear amplification-mediated polymerase chain reaction (nrLAM-PCR) protocol, vector structure-dependent integration site profiles were observed upon transduction of mouse lin- hematopoietic progenitors in vitro. Initial target site selection mainly depended on the presence of the promoter while being independent of its nature. Despite the increased propensity for read-through transcription of SIN lentiviral vectors, the incidence of viral-cellular fusion transcript formation involving the canonical viral splice donor or cryptic splice sites was reduced in both unselected primary lin- cells and transformed 32D cells. Moreover, the strength of the internal promoter in vectors with SIN LTRs is decisive for in vitro selection and for the abundance of chimeric transcripts, which are decreased by moderately active promoters. These results will help to better understand vector biology and to optimize therapeutic vectors for future gene therapy applications.
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Affiliation(s)
- Simone J Scholz
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany
| | - Raffaele Fronza
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany .,2 GeneWerk GmbH, Heidelberg, Germany
| | - Cynthia C Bartholomä
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany
| | - Daniela Cesana
- 3 San Raffaele Telethon Institute for Gene Therapy , Milan, Italy
| | - Eugenio Montini
- 3 San Raffaele Telethon Institute for Gene Therapy , Milan, Italy
| | - Christof von Kalle
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany
| | - Irene Gil-Farina
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany
| | - Manfred Schmidt
- 1 Department of Translational Oncology, German Cancer Research Center and National Center for Tumor Diseases , Heidelberg, Germany .,2 GeneWerk GmbH, Heidelberg, Germany
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29
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Detailed comparison of retroviral vectors and promoter configurations for stable and high transgene expression in human induced pluripotent stem cells. Gene Ther 2017; 24:298-307. [PMID: 28346436 DOI: 10.1038/gt.2017.20] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 01/27/2017] [Accepted: 03/06/2017] [Indexed: 12/19/2022]
Abstract
Correction of patient-specific induced pluripotent stem cells (iPSC) upon gene delivery through retroviral vectors offers new treatment perspectives for monogenetic diseases. Gene-modified iPSC clones can be screened for safe integration sites and differentiated into transplantable cells of interest. However, the current bottleneck is epigenetic vector silencing. In order to identify the most suitable retroviral expression system in iPSC, we systematically compared vectors from different retroviral genera, different promoters and their combination with ubiquitous chromatin opening elements (UCOE), and several envelope pseudotypes. Lentiviral vectors (LV) pseudotyped with vesicular stomatitis virus glycoprotein were superior to gammaretroviral and alpharetroviral vectors and other envelopes tested. The elongation factor 1α short (EFS) promoter mediated the most robust expression, whereas expression levels were lower from the potent but more silencing-prone spleen focus forming virus (SFFV) promoter. Both full-length (A2UCOE) and minimal (CBX3) UCOE juxtaposed to two physiological and one viral promoter reduced transgene silencing with equal efficiency. However, a promoter-specific decline in expression levels was not entirely prevented. Upon differentiation of transgene-positive iPSC into endothelial cells, A2UCOE.EFS and CBX3.EFS vectors maintained highest transgene expression in a larger fraction of cells as compared with all other constructs tested here. The function of UCOE diminished, but did not fully counteract, vector silencing and possibilities for improvements remain. Nevertheless, the CBX3.EFS in a LV background exhibited the most promising promoter and vector configuration for both high titer production and long-term genetic modification of human iPSC and their progeny.
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30
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El Ashkar S, Van Looveren D, Schenk F, Vranckx LS, Demeulemeester J, De Rijck J, Debyser Z, Modlich U, Gijsbers R. Engineering Next-Generation BET-Independent MLV Vectors for Safer Gene Therapy. MOLECULAR THERAPY-NUCLEIC ACIDS 2017. [PMID: 28624199 PMCID: PMC5415309 DOI: 10.1016/j.omtn.2017.04.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Retroviral vectors have shown their curative potential in clinical trials correcting monogenetic disorders. However, therapeutic benefits were compromised due to vector-induced dysregulation of cellular genes and leukemia development in a subset of patients. Bromodomain and extraterminal domain (BET) proteins act as cellular cofactors that tether the murine leukemia virus (MLV) pre-integration complex to host chromatin via interaction with the MLV integrase (IN) and thereby define the typical gammaretroviral integration distribution. We engineered next-generation BET-independent (Bin) MLV vectors to retarget their integration to regions where they are less likely to dysregulate nearby genes. We mutated MLV IN to uncouple BET protein interaction and fused it with chromatin-binding peptides. The addition of the CBX1 chromodomain to MLV INW390A efficiently targeted integration away from gene regulatory elements. The retargeted vector produced at high titers and efficiently transduced CD34+ hematopoietic stem cells, while fewer colonies were detected in a serial colony-forming assay, a surrogate test for genotoxicity. Our findings underscore the potential of the engineered vectors to reduce the risk of insertional mutagenesis without compromising transduction efficiency. Ultimately, combined with other safety features in vector design, next-generation BinMLV vectors can improve the safety of gammaretroviral vectors for gene therapy.
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Affiliation(s)
- Sara El Ashkar
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Dominique Van Looveren
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium
| | - Franziska Schenk
- RG Gene Modification in Stem Cells, LOEWE Center for Cell and Gene Therapy Frankfurt, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Lenard S Vranckx
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Jonas Demeulemeester
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Jan De Rijck
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Zeger Debyser
- Laboratory for Molecular Virology and Drug Discovery, Department of Pharmaceutical and Pharmacological Sciences, 3000 Leuven, KU Leuven, Belgium
| | - Ute Modlich
- RG Gene Modification in Stem Cells, LOEWE Center for Cell and Gene Therapy Frankfurt, Paul-Ehrlich-Institute, 63225 Langen, Germany
| | - Rik Gijsbers
- Laboratory for Viral Vector Technology and Gene Therapy, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium; Leuven Viral Vector Core, KU Leuven, 3000 Leuven, Belgium.
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31
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Dong AC, Rivella S. Gene Addition Strategies for β-Thalassemia and Sickle Cell Anemia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1013:155-176. [PMID: 29127680 DOI: 10.1007/978-1-4939-7299-9_6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Beta-thalassemia and sickle cell anemia are two of the most common diseases related to the hemoglobin protein. In these diseases, the beta-globin gene is mutated, causing severe anemia and ineffective erythropoiesis. Patients can additionally present with a number of life-threatening co-morbidities, such as stroke or spontaneous fractures. Current treatment involves transfusion and iron chelation; allogeneic bone marrow transplant is the only curative option, but is limited by the availability of matching donors and graft-versus-host disease. As these two diseases are monogenic diseases, they make an attractive setting for gene therapy. Gene therapy aims to correct the mutated beta-globin gene or add back a functional copy of beta- or gamma-globin. Initial gene therapy work was done with oncoretroviral vectors, but has since shifted to lentiviral vectors. Currently, there are a few clinical trials underway to test the curative potential of some of these lentiviral vectors. This review will highlight the work done thus far, and present the challenges still facing gene therapy, such as genome toxicity concerns and achieving sufficient transgene expression to cure those with the most severe forms of thalassemia.
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Affiliation(s)
- Alisa C Dong
- Division of Hematology-Oncology, Department of Pediatrics, Weill Cornell Medical College, 515 E. 71st St., Room S-709, New York, NY, 10021, USA
| | - Stefano Rivella
- Division of Hematology-Oncology, Department of Pediatrics, Weill Cornell Medical College, 515 E. 71st St., S702, Box 284, New York, NY, 10021, USA.
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32
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Mansilla-Soto J, Riviere I, Boulad F, Sadelain M. Cell and Gene Therapy for the Beta-Thalassemias: Advances and Prospects. Hum Gene Ther 2016; 27:295-304. [PMID: 27021486 DOI: 10.1089/hum.2016.037] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
The beta-thalassemias are inherited anemias caused by mutations that severely reduce or abolish expression of the beta-globin gene. Like sickle cell disease, a related beta-globin gene disorder, they are ideal candidates for performing a genetic correction in patient hematopoietic stem cells (HSCs). The most advanced approach utilizes complex lentiviral vectors encoding the human β-globin gene, as first reported by May et al. in 2000. Considerable progress toward the clinical implementation of this approach has been made in the past five years, based on effective CD34+ cell mobilization and improved lentiviral vector manufacturing. Four trials have been initiated in the United States and Europe. Of 16 evaluable subjects, 6 have achieved transfusion independence. One of them developed a durable clonal expansion, which regressed after several years without transformation. Although globin lentiviral vectors have so far proven to be safe, this occurrence suggests that powerful insulators with robust enhancer-blocking activity will further enhance this approach. The combined discovery of Bcl11a-mediated γ-globin gene silencing and advances in gene editing are the foundations for another gene therapy approach, which aims to reactivate fetal hemoglobin (HbF) production. Its clinical translation will hinge on the safety and efficiency of gene targeting in true HSCs and the induction of sufficient levels of HbF to achieve transfusion independence. Altogether, the progress achieved over the past 15 years bodes well for finding a genetic cure for severe globin disorders in the next decade.
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Affiliation(s)
- Jorge Mansilla-Soto
- 1 Center for Cell Engineering, Memorial Sloan Kettering Cancer Center , New York, New York
| | - Isabelle Riviere
- 1 Center for Cell Engineering, Memorial Sloan Kettering Cancer Center , New York, New York
| | - Farid Boulad
- 1 Center for Cell Engineering, Memorial Sloan Kettering Cancer Center , New York, New York.,2 Department of Pediatrics, Memorial Sloan Kettering Cancer Center , New York, New York
| | - Michel Sadelain
- 1 Center for Cell Engineering, Memorial Sloan Kettering Cancer Center , New York, New York
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33
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Browning DL, Everson EM, Leap DJ, Hocum JD, Wang H, Stamatoyannopoulos G, Trobridge GD. Evidence for the in vivo safety of insulated foamy viral vectors. Gene Ther 2016; 24:187-198. [PMID: 28024082 PMCID: PMC5374020 DOI: 10.1038/gt.2016.88] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 11/28/2016] [Accepted: 12/05/2016] [Indexed: 12/15/2022]
Abstract
Retroviral vector mediated stem cell gene therapy is a promising approach for the treatment of hematopoietic disorders. However, genotoxic side effects from integrated vector proviruses are a significant concern for the use of retroviral vectors in the clinic. Insulated foamy viral (FV) vectors are potentially safer retroviral vectors for hematopoietic stem cell gene therapy. We evaluated two newly identified human insulators, A1 and A2 for use in FV vectors. These insulators had moderate insulating capacity and higher titers than previously developed insulated FV vectors. The A1 insulated FV vector was chosen for comparison with the previously described 650cHS4 insulated FV vector in human cord blood CD34+ repopulating cells in an immunodeficient mouse model. To maximize the effects of the insulators on the safety of FV vectors, FV vectors containing a highly genotoxic spleen focus forming virus (SFFV) promoter was used to elicit differences in genotoxicity. In vivo, the A1 insulated FV vector showed an approximate 50% reduction in clonal dominance compared to either the 650cHS4 insulated or control FV vectors, although the transduction efficiency of the A1 insulated vector was higher. This data suggests that the A1 insulated FV vector is promising for future pre-clinical and clinical studies.
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Affiliation(s)
- D L Browning
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA
| | - E M Everson
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - D J Leap
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - J D Hocum
- Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
| | - H Wang
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, USA
| | - G Stamatoyannopoulos
- Department of Medicine, Division of Medical Genetics, University of Washington, Seattle, WA, USA
| | - G D Trobridge
- School of Molecular Biosciences, Washington State University, Pullman, WA, USA.,Department of Pharmaceutical Sciences, Washington State University, Spokane, WA, USA
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34
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Singh S, Khan I, Khim S, Seymour B, Sommer K, Wielgosz M, Norgaard Z, Kiem HP, Adair J, Liggitt D, Nienhuis A, Rawlings DJ. Safe and Effective Gene Therapy for Murine Wiskott-Aldrich Syndrome Using an Insulated Lentiviral Vector. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2016; 4:1-16. [PMID: 28344987 PMCID: PMC5363182 DOI: 10.1016/j.omtm.2016.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Accepted: 11/15/2016] [Indexed: 12/18/2022]
Abstract
Wiskott-Aldrich syndrome (WAS) is a life-threatening immunodeficiency caused by mutations within the WAS gene. Viral gene therapy to restore WAS protein (WASp) expression in hematopoietic cells of patients with WAS has the potential to improve outcomes relative to the current standard of care, allogeneic bone marrow transplantation. However, the development of viral vectors that are both safe and effective has been problematic. While use of viral transcriptional promoters may increase the risk of insertional mutagenesis, cellular promoters may not achieve WASp expression levels necessary for optimal therapeutic effect. Here we evaluate a self-inactivating (SIN) lentiviral vector combining a chromatin insulator upstream of a viral MND (MPSV LTR, NCR deleted, dl587 PBS) promoter driving WASp expression. Used as a gene therapeutic in Was−/− mice, this vector resulted in stable WASp+ cells in all hematopoietic lineages and rescue of T and B cell defects with a low number of viral integrations per cell, without evidence of insertional mutagenesis in serial bone marrow transplants. In a gene transfer experiment in non-human primates, the insulated MND promoter (driving GFP expression) demonstrated long-term polyclonal engraftment of GFP+ cells. These observations demonstrate that the insulated MND promoter safely and efficiently reconstitutes clinically effective WASp expression and should be considered for future WAS therapy.
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Affiliation(s)
- Swati Singh
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Iram Khan
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Socheath Khim
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Brenda Seymour
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Karen Sommer
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA
| | - Matthew Wielgosz
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Zachary Norgaard
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Hans-Peter Kiem
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Pathology, University of Washington, Seattle, WA 98105, USA
| | - Jennifer Adair
- Clinical Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA; Department of Medical Oncology, University of Washington, Seattle, WA 98105, USA
| | - Denny Liggitt
- Department of Comparative Medicine, University of Washington, Seattle, WA 98105, USA
| | - Arthur Nienhuis
- Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - David J Rawlings
- Center for Immunity and Immunotherapies and Program for Cell and Gene Therapy, Seattle Children's Research Institute, Seattle, WA 98101, USA; Department of Pediatrics, University of Washington, Seattle, WA 98105, USA; Department of Immunology, University of Washington, Seattle, WA 98105, USA
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35
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Abstract
Viral vector use in gene therapy has highlighted several safety concerns, including genotoxic events. Generally, vector-mediated genotoxicity results from upregulation of cellular proto-oncogenes via promoter insertion, promoter activation, or gene transcript truncation, with enhancer-mediated activation of nearby genes the primary mechanism reported in gene therapy trials. Vector-mediated genotoxicity can be influenced by virus type, integration target site, and target cell type; different vectors have distinct integration profiles which are cell-specific. Non-viral factors, including patient age, disease, and dose can also influence genotoxic potential, thus the choice of test models and clinical trial populations is important to ensure they are indicative of efficacy and safety. Efforts have been made to develop viral vectors with less risk of insertional mutagenesis, including self-inactivating (SIN) vectors, enhancer-blocking insulators, and microRNA targeting of vectors, although insertional mutagenesis is not completely abrogated. Here we provide an overview of the current understanding of viral vector-mediated genotoxicity risk from factors contributing to viral vector-mediated genotoxicity to efforts made to reduce genotoxicity, and testing strategies required to adequately assess the risk of insertional mutagenesis. It is clear that there is not a 'one size fits all' approach to vector modification for reducing genotoxicity, and addressing these challenges will be a key step in the development of therapies such as CRISPR-Cas9 and delivery of future gene-editing technologies.
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Affiliation(s)
- Rhiannon M David
- Genetic Toxicology, Discovery Safety, AstraZeneca, Cambridge, CB4 0WG, UK
| | - Ann T Doherty
- Genetic Toxicology, Discovery Safety, AstraZeneca, Cambridge, CB4 0WG, UK
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Towards a Safer, More Randomized Lentiviral Vector Integration Profile Exploring Artificial LEDGF Chimeras. PLoS One 2016; 11:e0164167. [PMID: 27788138 PMCID: PMC5082951 DOI: 10.1371/journal.pone.0164167] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 09/20/2016] [Indexed: 11/19/2022] Open
Abstract
The capacity to integrate transgenes into the host cell genome makes retroviral vectors an interesting tool for gene therapy. Although stable insertion resulted in successful correction of several monogenic disorders, it also accounts for insertional mutagenesis, a major setback in otherwise successful clinical gene therapy trials due to leukemia development in a subset of treated patients. Despite improvements in vector design, their use is still not risk-free. Lentiviral vector (LV) integration is directed into active transcription units by LEDGF/p75, a host-cell protein co-opted by the viral integrase. We engineered LEDGF/p75-based hybrid tethers in an effort to elicit a more random integration pattern to increase biosafety, and potentially reduce proto-oncogene activation. We therefore truncated LEDGF/p75 by deleting the N-terminal chromatin-reading PWWP-domain, and replaced this domain with alternative pan-chromatin binding peptides. Expression of these LEDGF-hybrids in LEDGF-depleted cells efficiently rescued LV transduction and resulted in LV integrations that distributed more randomly throughout the host-cell genome. In addition, when considering safe harbor criteria, LV integration sites for these LEDGF-hybrids distributed more safely compared to LEDGF/p75-mediated integration in wild-type cells. This approach should be broadly applicable to introduce therapeutic or suicide genes for cell therapy, such as patient-specific iPS cells.
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Chira S, Jackson CS, Oprea I, Ozturk F, Pepper MS, Diaconu I, Braicu C, Raduly LZ, Calin GA, Berindan-Neagoe I. Progresses towards safe and efficient gene therapy vectors. Oncotarget 2016; 6:30675-703. [PMID: 26362400 PMCID: PMC4741561 DOI: 10.18632/oncotarget.5169] [Citation(s) in RCA: 134] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 08/22/2015] [Indexed: 12/11/2022] Open
Abstract
The emergence of genetic engineering at the beginning of the 1970′s opened the era of biomedical technologies, which aims to improve human health using genetic manipulation techniques in a clinical context. Gene therapy represents an innovating and appealing strategy for treatment of human diseases, which utilizes vehicles or vectors for delivering therapeutic genes into the patients' body. However, a few past unsuccessful events that negatively marked the beginning of gene therapy resulted in the need for further studies regarding the design and biology of gene therapy vectors, so that this innovating treatment approach can successfully move from bench to bedside. In this paper, we review the major gene delivery vectors and recent improvements made in their design meant to overcome the issues that commonly arise with the use of gene therapy vectors. At the end of the manuscript, we summarized the main advantages and disadvantages of common gene therapy vectors and we discuss possible future directions for potential therapeutic vectors.
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Affiliation(s)
- Sergiu Chira
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania
| | - Carlo S Jackson
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | - Iulian Oprea
- Department of Oncology and Pathology, Cancer Center Karolinska, Karolinska Institutet and Karolinska University Hospital, Stockholm, Sweden
| | - Ferhat Ozturk
- Department of Molecular Biology and Genetics, Canik Başari University, Samsun, Turkey
| | - Michael S Pepper
- Department of Immunology and Institute for Cellular and Molecular Medicine, Faculty of Health Sciences, University of Pretoria, Pretoria, South Africa
| | | | - Cornelia Braicu
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania
| | - Lajos-Zsolt Raduly
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Physiopathology, Faculty of Veterinary Medicine, University of Agricultural Science and Veterinary Medicine, Cluj Napoca, Romania
| | - George A Calin
- Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.,Center for RNA Interference and Non-Coding RNAs, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Ioana Berindan-Neagoe
- Research Center for Functional Genomics, Biomedicine and Translational Medicine, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Immunology, University of Medicine and Pharmacy "Iuliu Haţieganu", Cluj Napoca, Romania.,Department of Functional Genomics and Experimental Pathology, Oncological Institute "Prof. Dr. Ion Chiricuţă", Cluj Napoca, Romania.,Department of Experimental Therapeutics, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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Baiamonte E, Spinelli G, Maggio A, Acuto S, Cavalieri V. The Sea Urchin sns5 Chromatin Insulator Shapes the Chromatin Architecture of a Lentivirus Vector Integrated in the Mammalian Genome. Nucleic Acid Ther 2016; 26:318-326. [PMID: 27248156 DOI: 10.1089/nat.2016.0614] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lentivirus vectors are presently the favorite vehicles for therapeutic gene transfer in hematopoietic cells. Nonetheless, these vectors integrate randomly throughout the genome, exhibiting variegation of transgene expression due to the spreading of heterochromatin into the vector sequences. Moreover, the cis-regulatory elements harbored by the vector could disturb the proper transcription of resident genes neighboring the integration site. The incorporation of chromatin insulators in flanking position to the transferred unit can alleviate both the above-mentioned dangerous effects, due to the insulator-specific barrier and enhancer-blocking activities. In this study, we report the valuable properties of the sea urchin-derived sns5 insulator in improving the expression efficiency of a lentivirus vector integrated in the mammalian erythroid genome. We show that these results neither reflect an intrinsic sns5 enhancer activity nor rely on the recruitment of the erythroid-specific GATA-1 factor to sns5. Furthermore, by using the Chromosome Conformation Capture technology, we report that a single copy of the sns5-insulated vector is specifically organized into an independent chromatin loop at the provirus locus. Our results not only provide new clues concerning the molecular mechanism of sns5 function in the erythroid genome but also reassure the use of sns5 to improve the performance of gene therapy vectors.
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Affiliation(s)
- Elena Baiamonte
- 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy
| | - Giovanni Spinelli
- 2 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo , Palermo, Italy
| | - Aurelio Maggio
- 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy
| | - Santina Acuto
- 1 Campus of Haematology Franco e Piera Cutino, Villa Sofia-Cervello Hospital , Palermo, Italy
| | - Vincenzo Cavalieri
- 2 Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo , Palermo, Italy
- 3 Mediterranean Center for Human Health Advanced Biotechnologies (CHAB), University of Palermo , Palermo, Italy
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Browning DL, Collins CP, Hocum JD, Leap DJ, Rae DT, Trobridge GD. Insulated Foamy Viral Vectors. Hum Gene Ther 2016; 27:255-66. [PMID: 26715244 PMCID: PMC4800274 DOI: 10.1089/hum.2015.110] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 12/24/2015] [Indexed: 01/12/2023] Open
Abstract
Retroviral vector-mediated gene therapy is promising, but genotoxicity has limited its use in the clinic. Genotoxicity is highly dependent on the retroviral vector used, and foamy viral (FV) vectors appear relatively safe. However, internal promoters may still potentially activate nearby genes. We developed insulated FV vectors, using four previously described insulators: a version of the well-studied chicken hypersensitivity site 4 insulator (650cHS4), two synthetic CCCTC-binding factor (CTCF)-based insulators, and an insulator based on the CCAAT box-binding transcription factor/nuclear factor I (7xCTF/NF1). We directly compared these insulators for enhancer-blocking activity, effect on FV vector titer, and fidelity of transfer to both proviral long terminal repeats. The synthetic CTCF-based insulators had the strongest insulating activity, but reduced titers significantly. The 7xCTF/NF1 insulator did not reduce titers but had weak insulating activity. The 650cHS4-insulated FV vector was identified as the overall most promising vector. Uninsulated and 650cHS4-insulated FV vectors were both significantly less genotoxic than gammaretroviral vectors. Integration sites were evaluated in cord blood CD34(+) cells and the 650cHS4-insulated FV vector had fewer hotspots compared with an uninsulated FV vector. These data suggest that insulated FV vectors are promising for hematopoietic stem cell gene therapy.
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Affiliation(s)
- Diana L. Browning
- School of Molecular Biosciences, Washington State University, Pullman
| | - Casey P. Collins
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Jonah D. Hocum
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - David J. Leap
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Dustin T. Rae
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
| | - Grant D. Trobridge
- School of Molecular Biosciences, Washington State University, Pullman
- Department of Pharmaceutical Sciences, Washington State University, Spokane, Washington
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40
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West DB, Engelhard EK, Adkisson M, Nava AJ, Kirov JV, Cipollone A, Willis B, Rapp J, de Jong PJ, Lloyd KC. Transcriptome Analysis of Targeted Mouse Mutations Reveals the Topography of Local Changes in Gene Expression. PLoS Genet 2016; 12:e1005691. [PMID: 26839965 PMCID: PMC4739719 DOI: 10.1371/journal.pgen.1005691] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 10/30/2015] [Indexed: 01/21/2023] Open
Abstract
The unintended consequences of gene targeting in mouse models have not been thoroughly studied and a more systematic analysis is needed to understand the frequency and characteristics of off-target effects. Using RNA-seq, we evaluated targeted and neighboring gene expression in tissues from 44 homozygous mutants compared with C57BL/6N control mice. Two allele types were evaluated: 15 targeted trap mutations (TRAP); and 29 deletion alleles (DEL), usually a deletion between the translational start and the 3' UTR. Both targeting strategies insert a bacterial beta-galactosidase reporter (LacZ) and a neomycin resistance selection cassette. Evaluating transcription of genes in +/- 500 kb of flanking DNA around the targeted gene, we found up-regulated genes more frequently around DEL compared with TRAP alleles, however the frequency of alleles with local down-regulated genes flanking DEL and TRAP targets was similar. Down-regulated genes around both DEL and TRAP targets were found at a higher frequency than expected from a genome-wide survey. However, only around DEL targets were up-regulated genes found with a significantly higher frequency compared with genome-wide sampling. Transcriptome analysis confirms targeting in 97% of DEL alleles, but in only 47% of TRAP alleles probably due to non-functional splice variants, and some splicing around the gene trap. Local effects on gene expression are likely due to a number of factors including compensatory regulation, loss or disruption of intragenic regulatory elements, the exogenous promoter in the neo selection cassette, removal of insulating DNA in the DEL mutants, and local silencing due to disruption of normal chromatin organization or presence of exogenous DNA. An understanding of local position effects is important for understanding and interpreting any phenotype attributed to targeted gene mutations, or to spontaneous indels.
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Affiliation(s)
- David B. West
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, California, United States of America
- * E-mail:
| | - Eric K. Engelhard
- Mouse Biology Program, University of California, Davis, California, United States of America
| | - Michael Adkisson
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, California, United States of America
| | - A. J. Nava
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, California, United States of America
| | - Julia V. Kirov
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, California, United States of America
| | - Andreanna Cipollone
- Mouse Biology Program, University of California, Davis, California, United States of America
| | - Brandon Willis
- Mouse Biology Program, University of California, Davis, California, United States of America
| | - Jared Rapp
- Mouse Biology Program, University of California, Davis, California, United States of America
| | - Pieter J. de Jong
- Children’s Hospital Oakland Research Institute (CHORI), Oakland, California, United States of America
| | - Kent C. Lloyd
- Mouse Biology Program, University of California, Davis, California, United States of America
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Abstract
Retroviral vector gene therapy is a promising approach to treating HIV-1. However, integrated vectors are mutagens with the potential to dysregulate nearby genes and cause severe adverse side effects. Leukemia has already been a documented severe adverse event in gene therapy clinical trials for the treatment of primary immunodeficiencies. These side effects will need to be reduced or avoided if retroviral vectors are to be used clinically for HIV-1 treatment. The addition of chromatin insulators to retroviral vectors is a potential strategy for reducing adverse side effects. Insulators have already been effectively used in retroviral vectors to reduce genotoxicity in pre-clinical studies. Here, we will review how insulators function, genotoxicity in gene therapy clinical trials, the design of insulated retroviral vectors, promising results from insulated retroviral vector studies, and considerations for the development of insulated retroviral treatment vectors for HIV-1 gene therapy.
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Affiliation(s)
- Diana L. Browning
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA;
| | - Grant D. Trobridge
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164, USA;
- Pharmaceutical Sciences, College of Pharmacy, Washington State University Spokane, Spokane, WA 99202, USA
- Correspondence: ; Tel.: +1-509-368-6535
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42
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Abstract
The rapid advances in the field of genome editing using targeted endonucleases have called considerable attention to the potential of this technology for human gene therapy. Targeted correction of disease-causing mutations could ensure lifelong, tissue-specific expression of the relevant gene, thereby alleviating or resolving a specific disease phenotype. In this review, we aim to explore the potential of this technology for the therapy of β-thalassemia. This blood disorder is caused by mutations in the gene encoding the β-globin chain of hemoglobin, leading to severe anemia in affected patients. Curative allogeneic bone marrow transplantation is available only to a small subset of patients, leaving the majority of patients dependent on regular blood transfusions and iron chelation therapy. The transfer of gene-corrected autologous hematopoietic stem cells could provide a therapeutic alternative, as recent results from gene therapy trials using a lentiviral gene addition approach have demonstrated. Genome editing has the potential to further advance this approach as it eliminates the need for semi-randomly integrating viral vectors and their associated risk of insertional mutagenesis. In the following pages we will highlight the advantages and risks of genome editing compared to standard therapy for β-thalassemia and elaborate on lessons learned from recent gene therapy trials.
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Affiliation(s)
- Astrid Glaser
- 1Murdoch Childrens Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia
| | - Bradley McColl
- 1Murdoch Childrens Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia
| | - Jim Vadolas
- 1Murdoch Childrens Research Institute, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia; Department of Paediatrics, University of Melbourne, Royal Children's Hospital, 50 Flemington Rd, Parkville, VIC, 3052, Australia
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43
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Zulliger R, Conley SM, Naash MI. Non-viral therapeutic approaches to ocular diseases: An overview and future directions. J Control Release 2015; 219:471-487. [PMID: 26439665 PMCID: PMC4699668 DOI: 10.1016/j.jconrel.2015.10.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Revised: 10/01/2015] [Accepted: 10/02/2015] [Indexed: 12/31/2022]
Abstract
Currently there are no viable treatment options for patients with debilitating inherited retinal degeneration. The vast variability in disease-inducing mutations and resulting phenotypes has hampered the development of therapeutic interventions. Gene therapy is a logical approach, and recent work has focused on ways to optimize vector design and packaging to promote optimized expression and phenotypic rescue after intraocular delivery. In this review, we discuss ongoing ocular clinical trials, which currently use viral gene delivery, but focus primarily on new advancements in optimizing the efficacy of non-viral gene delivery for ocular diseases. Non-viral delivery systems are highly customizable, allowing functionalization to improve cellular and nuclear uptake, bypassing cellular degradative machinery, and improving gene expression in the nucleus. Non-viral vectors often yield transgene expression levels lower than viral counterparts, however their favorable safety/immune profiles and large DNA capacity (critical for the delivery of large ocular disease genes) make their further development a research priority. Recent work on particle coating and vector engineering presents exciting ways to overcome limitations of transient/low gene expression levels, but also highlights the fact that further refinements are needed before use in the clinic.
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Affiliation(s)
- Rahel Zulliger
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204-5060, United States
| | - Shannon M Conley
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, United States
| | - Muna I Naash
- Department of Biomedical Engineering, University of Houston, Houston, TX 77204-5060, United States.
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44
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Maksimenko O, Gasanov NB, Georgiev P. Regulatory Elements in Vectors for Efficient Generation of Cell Lines Producing Target Proteins. Acta Naturae 2015; 7:15-26. [PMID: 26483956 PMCID: PMC4610161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To date, there has been an increasing number of drugs produced in mammalian cell cultures. In order to enhance the expression level and stability of target recombinant proteins in cell cultures, various regulatory elements with poorly studied mechanisms of action are used. In this review, we summarize and discuss the potential mechanisms of action of such regulatory elements.
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Affiliation(s)
- O. Maksimenko
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
| | - N. B. Gasanov
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
| | - P. Georgiev
- Institute of Gene Biology, Russian Academy of Sciences, Vavilova str. 34/5, 119334, Moscow, Russia
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45
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Progress in gene therapy for primary immunodeficiencies using lentiviral vectors. Curr Opin Allergy Clin Immunol 2015; 14:527-34. [PMID: 25207699 DOI: 10.1097/aci.0000000000000114] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
PURPOSE OF REVIEW This review gives an overview over the most recent progress in the field of lentiviral gene therapy for primary immunodeficiencies (PIDs). The history and state-of-the-art of lentiviral vector development are summarized and the recent advancements for a number of selected diseases are reviewed in detail. Past retroviral vector trials for these diseases, the most recent improvements of lentiviral vector platforms and their application in preclinical development as well as ongoing clinical trials are discussed. RECENT FINDINGS Main focus is on the preclinical studies and clinical trials for the treatment of Wiskott-Aldrich syndrome, chronic granulomatous disease, adenosine deaminase deficient severe combined immunodeficiency (ADA-SCID) and X-linked severe combined immunodeficiency with lentiviral gene therapy. SUMMARY Gene therapy for PIDs is an effective treatment, providing potential long-term clinical benefit for affected patients. Substantial progress has been made to make lentiviral gene therapy platforms available for a number of rare genetic diseases. Although many ongoing gene therapy trials are based on ex-vivo approaches with autologous hematopoietic stem cells, other approaches such as in-vivo gene therapy or gene-repair platforms might provide further advancement for certain PIDs.
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Romero Z, Campo-Fernandez B, Wherley J, Kaufman ML, Urbinati F, Cooper AR, Hoban MD, Baldwin KM, Lumaquin D, Wang X, Senadheera S, Hollis RP, Kohn DB. The human ankyrin 1 promoter insulator sustains gene expression in a β-globin lentiviral vector in hematopoietic stem cells. Mol Ther Methods Clin Dev 2015; 2:15012. [PMID: 26029723 PMCID: PMC4445009 DOI: 10.1038/mtm.2015.12] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 02/20/2015] [Indexed: 02/06/2023]
Abstract
Lentiviral vectors designed for the treatment of the hemoglobinopathies require the inclusion of regulatory and strong enhancer elements to achieve sufficient expression of the β-globin transgene. Despite the inclusion of these elements, the efficacy of these vectors may be limited by transgene silencing due to the genomic environment surrounding the integration site. Barrier insulators can be used to give more consistent expression and resist silencing even with lower vector copies. Here, the barrier activity of an insulator element from the human ankyrin-1 gene was analyzed in a lentiviral vector carrying an antisickling human β-globin gene. Inclusion of a single copy of the Ankyrin insulator did not affect viral titer, and improved the consistency of expression from the vector in murine erythroleukemia cells. The presence of the Ankyrin insulator element did not change transgene expression in human hematopoietic cells in short-term erythroid culture or in vivo in primary murine transplants. However, analysis in secondary recipients showed that the lentiviral vector with the Ankyrin element preserved transgene expression, whereas expression from the vector lacking the Ankyrin insulator decreased in secondary recipients. These studies demonstrate that the Ankyrin insulator may improve long-term β-globin expression in hematopoietic stem cells for gene therapy of hemoglobinopathies.
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Affiliation(s)
- Zulema Romero
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Beatriz Campo-Fernandez
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Jennifer Wherley
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Michael L Kaufman
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Fabrizia Urbinati
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Aaron R Cooper
- Molecular Biology Interdepartmental PhD Program, University of California, Los Angeles, California, USA
| | - Megan D Hoban
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Kismet M Baldwin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Dianne Lumaquin
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Xiaoyan Wang
- Department of Internal Medicine and Health Services Research, University of California, Los Angeles, California, USA
| | - Shantha Senadheera
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Roger P Hollis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
| | - Donald B Kohn
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, California, USA
- Department of Pediatrics, UCLA Children’s Discovery and Innovation Institute David Geffen School of Medicine, University of California, Los Angeles, California, USA
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Müller-Kuller U, Ackermann M, Kolodziej S, Brendel C, Fritsch J, Lachmann N, Kunkel H, Lausen J, Schambach A, Moritz T, Grez M. A minimal ubiquitous chromatin opening element (UCOE) effectively prevents silencing of juxtaposed heterologous promoters by epigenetic remodeling in multipotent and pluripotent stem cells. Nucleic Acids Res 2015; 43:1577-92. [PMID: 25605798 PMCID: PMC4330381 DOI: 10.1093/nar/gkv019] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Epigenetic silencing of transgene expression represents a major obstacle for the efficient genetic modification of multipotent and pluripotent stem cells. We and others have demonstrated that a 1.5 kb methylation-free CpG island from the human HNRPA2B1-CBX3 housekeeping genes (A2UCOE) effectively prevents transgene silencing and variegation in cell lines, multipotent and pluripotent stem cells, and their differentiated progeny. However, the bidirectional promoter activity of this element may disturb expression of neighboring genes. Furthermore, the epigenetic basis underlying the anti-silencing effect of the UCOE on juxtaposed promoters has been only partially explored. In this study we removed the HNRPA2B1 moiety from the A2UCOE and demonstrate efficient anti-silencing properties also for a minimal 0.7 kb element containing merely the CBX3 promoter. This DNA element largely prevents silencing of viral and tissue-specific promoters in multipotent and pluripotent stem cells. The protective activity of CBX3 was associated with reduced promoter CpG-methylation, decreased levels of repressive and increased levels of active histone marks. Moreover, the anti-silencing effect of CBX3 was locally restricted and when linked to tissue-specific promoters did not activate transcription in off target cells. Thus, CBX3 is a highly attractive element for sustained, tissue-specific and copy-number dependent transgene expression in vitro and in vivo.
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Affiliation(s)
- Uta Müller-Kuller
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Mania Ackermann
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Stephan Kolodziej
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Christian Brendel
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Jessica Fritsch
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Nico Lachmann
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Hana Kunkel
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Jörn Lausen
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
| | - Axel Schambach
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Division of Pediatric Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Thomas Moritz
- RG Reprogramming and Gene Therapy, REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany Institute of Experimental Hematology, Hannover Medical School, Hannover, Lower Saxony, 30625, Germany
| | - Manuel Grez
- Institute for Tumor Biology and Experimental Therapy, Georg-Speyer-Haus, Frankfurt, Hessen, 60596, Germany
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Liu M, Maurano MT, Wang H, Qi H, Song CZ, Navas PA, Emery DW, Stamatoyannopoulos JA, Stamatoyannopoulos G. Genomic discovery of potent chromatin insulators for human gene therapy. Nat Biotechnol 2015; 33:198-203. [PMID: 25580597 DOI: 10.1038/nbt.3062] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Accepted: 10/09/2014] [Indexed: 12/29/2022]
Abstract
Insertional mutagenesis and genotoxicity, which usually manifest as hematopoietic malignancy, represent major barriers to realizing the promise of gene therapy. Although insulator sequences that block transcriptional enhancers could mitigate or eliminate these risks, so far no human insulators with high functional potency have been identified. Here we describe a genomic approach for the identification of compact sequence elements that function as insulators. These elements are highly occupied by the insulator protein CTCF, are DNase I hypersensitive and represent only a small minority of the CTCF recognition sequences in the human genome. We show that the elements identified acted as potent enhancer blockers and substantially decreased the risk of tumor formation in a cancer-prone animal model. The elements are small, can be efficiently accommodated by viral vectors and have no detrimental effects on viral titers. The insulators we describe here are expected to increase the safety of gene therapy for genetic diseases.
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Affiliation(s)
- Mingdong Liu
- Division of Medical Genetics, University of Washington, Seattle, Washington, USA
| | - Matthew T Maurano
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Hao Wang
- Department of Genome Sciences, University of Washington, Seattle, Washington, USA
| | - Heyuan Qi
- 1] Division of Medical Genetics, University of Washington, Seattle, Washington, USA. [2] Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
| | - Chao-Zhong Song
- 1] Division of Medical Genetics, University of Washington, Seattle, Washington, USA. [2] Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
| | - Patrick A Navas
- Division of Medical Genetics, University of Washington, Seattle, Washington, USA
| | - David W Emery
- 1] Division of Medical Genetics, University of Washington, Seattle, Washington, USA. [2] Institute for Stem Cell and Regenerative Medicine, University of Washington, Seattle, Washington, USA
| | - John A Stamatoyannopoulos
- 1] Department of Genome Sciences, University of Washington, Seattle, Washington, USA. [2] Department of Medicine, University of Washington, Seattle, Washington, USA
| | - George Stamatoyannopoulos
- 1] Division of Medical Genetics, University of Washington, Seattle, Washington, USA. [2] Department of Genome Sciences, University of Washington, Seattle, Washington, USA
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Acuto S, Baiamonte E, Di Stefano R, Spina B, Barone R, Maggio A. Development and Recent Progresses of Gene Therapy for β-Thalassemia. THALASSEMIA REPORTS 2014. [DOI: 10.4081/thal.2014.2925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
β-thalassemias are among the most common inherited monogenic disorders worldwide due to mutations in the β-globin gene that reduce or abolish the production of the β-globin chain resulting in transfusion-dependent chronic anemia. Currently, the only curative treatment is allogeneic hematopoietic stem cells (HSCs) transplantation, but this option is limited by the a vailability of HLA-matched donor. Gene therapy, based on autologous transplantation of genetically corrected HSCs, holds the promise to treat patients lacking a compati ble bone marrow donor. I nit ial attempts of gene transfer have been unsuccessful due to limitations of available vectors to stably transfer a globin gene in HSCs and reach high and regulated expression in the erythroid progeny. With the advent of lentiviral vectors (LVs), based on human immunodeficiency virus, many of the initial limitations have been overcome. Since 2000 when Sadelain and co-workers first demonstrated successful globin gene transfer in murine thalassemia models with improvement of the phenotype using a recombinant β globin/LV, several other groups have developed different vectors encoding either β, γ or mutated globin genes and confirmed these results in both murine models and erythroid progeny derived from patient’s HSCs. In light of these encouraging results, research has recently moved into clinical trials that are ongoing or soon to begin. One participant in an ongoing gene transfer trial for β-thalassemia has achieved clinical benefit with elimination of his transfusi on re quirement. Here , dev elopmen t and recent progress of gene therapy for β-thalassemia is reviewed.
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Gschweng EH, McCracken MN, Kaufman ML, Ho M, Hollis RP, Wang X, Saini N, Koya RC, Chodon T, Ribas A, Witte ON, Kohn DB. HSV-sr39TK positron emission tomography and suicide gene elimination of human hematopoietic stem cells and their progeny in humanized mice. Cancer Res 2014; 74:5173-83. [PMID: 25038231 DOI: 10.1158/0008-5472.can-14-0376] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Engineering immunity against cancer by the adoptive transfer of hematopoietic stem cells (HSC) modified to express antigen-specific T-cell receptors (TCR) or chimeric antigen receptors generates a continual supply of effector T cells, potentially providing superior anticancer efficacy compared with the infusion of terminally differentiated T cells. Here, we demonstrate the in vivo generation of functional effector T cells from CD34-enriched human peripheral blood stem cells modified with a lentiviral vector designed for clinical use encoding a TCR recognizing the cancer/testes antigen NY-ESO-1, coexpressing the PET/suicide gene sr39TK. Ex vivo analysis of T cells showed antigen- and HLA-restricted effector function against melanoma. Robust engraftment of gene-modified human cells was demonstrated with PET reporter imaging in hematopoietic niches such as femurs, humeri, vertebrae, and the thymus. Safety was demonstrated by the in vivo ablation of PET signal, NY-ESO-1-TCR-bearing cells, and integrated lentiviral vector genomes upon treatment with ganciclovir, but not with vehicle control. Our study provides support for the efficacy and safety of gene-modified HSCs as a therapeutic modality for engineered cancer immunotherapy. Cancer Res; 74(18); 5173-83. ©2014 AACR.
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Affiliation(s)
- Eric H Gschweng
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Melissa N McCracken
- Department of Medical and Molecular Pharmacology, University of California, Los Angeles, Los Angeles, California
| | - Michael L Kaufman
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Michelle Ho
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Roger P Hollis
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Xiaoyan Wang
- Department of Medicine Statistics Core, University of Los Angeles, Los Angeles, Los Angeles, California
| | - Navdeep Saini
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California
| | - Richard C Koya
- Center for Immunotherapy, Roswell Park Cancer Institute, Buffalo, New York
| | - Thinle Chodon
- Center for Immunotherapy, Roswell Park Cancer Institute, Buffalo, New York
| | - Antoni Ribas
- Department of Medical and Molecular Pharmacology, University of California, Los Angeles, Los Angeles, California. Department of Medicine, Division of Hematology/Oncology, University of California, Los Angeles, Los Angeles, California. Jonsson Comprehensive Cancer Center, Los Angeles, California. The Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Los Angeles, California
| | - Owen N Witte
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California. Department of Medical and Molecular Pharmacology, University of California, Los Angeles, Los Angeles, California. Jonsson Comprehensive Cancer Center, Los Angeles, California. The Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Los Angeles, California
| | - Donald B Kohn
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, Los Angeles, California. Jonsson Comprehensive Cancer Center, Los Angeles, California. The Eli and Edythe Broad Center for Regenerative Medicine and Stem Cell Research, Los Angeles, California. Department of Pediatrics, Division of Hematology/Oncology, Mattel Children's Hospital, University of California, Los Angeles, Los Angeles, California.
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