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Maurer AC, Benyamini B, Fan VB, Whitney ON, Dailey GM, Darzacq X, Weitzman MD, Tjian R. Double-Strand Break Repair Pathways Differentially Affect Processing and Transduction by Dual AAV Vectors. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.19.558438. [PMID: 37790316 PMCID: PMC10542147 DOI: 10.1101/2023.09.19.558438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Recombinant adeno-associated viral vectors (rAAV) are a powerful tool for gene delivery but have a limited DNA carrying capacity. Efforts to expand this genetic payload have focused on engineering the vector components, such as dual trans-splicing vectors which double the delivery size by exploiting the natural concatenation of rAAV genomes in host nuclei. We hypothesized that inefficient dual vector transduction could be improved by modulating host factors which affect concatenation. Since factors mediating concatenation are not well defined, we performed a genome-wide screen to identify host cell regulators. We discovered that Homologous Recombination (HR) is inhibitory to dual vector transduction. We demonstrate that depletion or inhibition of HR factors BRCA1 and Rad51 significantly increase reconstitution of a large split transgene by increasing both concatenation and expression from rAAVs. Our results define new roles for DNA damage repair in rAAV transduction and highlight the potential for pharmacological intervention to increase genetic payload of rAAV vectors.
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Affiliation(s)
- Anna C. Maurer
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- CIRM Center of Excellence, University of California, Berkeley, CA
| | - Brian Benyamini
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Vinson B. Fan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Oscar N. Whitney
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Gina M. Dailey
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, CA, USA
| | - Xavier Darzacq
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, CA, USA
| | - Matthew D. Weitzman
- University of Pennsylvania Perelman School of Medicine and the Children’s Hospital of Philadelphia, Philadelphia, PA, USA
| | - Robert Tjian
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
- Li Ka Shing Center for Biomedical & Health Sciences, University of California, Berkeley, CA, USA
- Howard Hughes Medical Institute, University of California, Berkeley, CA, USA
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2
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Ngo AM, Puschnik AS. Genome-Scale Analysis of Cellular Restriction Factors That Inhibit Transgene Expression from Adeno-Associated Virus Vectors. J Virol 2023; 97:e0194822. [PMID: 36971544 PMCID: PMC10134838 DOI: 10.1128/jvi.01948-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 03/01/2023] [Indexed: 03/29/2023] Open
Abstract
Adeno-associated virus (AAV) vectors are one of the leading platforms for gene delivery for the treatment of human genetic diseases, but the antiviral cellular mechanisms that interfere with optimal transgene expression are incompletely understood. Here, we performed two genome-scale CRISPR screens to identify cellular factors that restrict transgene expression from recombinant AAV vectors. Our screens revealed several components linked to DNA damage response, chromatin remodeling, and transcriptional regulation. Inactivation of the Fanconi anemia gene FANCA; the human silencing hub (HUSH)-associated methyltransferase SETDB1; and the gyrase, Hsp90, histidine kinase, and MutL (GHKL)-type ATPase MORC3 led to increased transgene expression. Moreover, SETDB1 and MORC3 knockout improved transgene levels of several AAV serotypes as well as other viral vectors, such as lentivirus and adenovirus. Finally, we demonstrated that the inhibition of FANCA, SETDB1, or MORC3 also enhanced transgene expression in human primary cells, suggesting that they could be physiologically relevant pathways that restrict AAV transgene levels in therapeutic settings. IMPORTANCE Recombinant AAV (rAAV) vectors have been successfully developed for the treatment of genetic diseases. The therapeutic strategy often involves the replacement of a defective gene by the expression of a functional copy from the rAAV vector genome. However, cells possess antiviral mechanisms that recognize and silence foreign DNA elements thereby limiting transgene expression and its therapeutic effect. Here, we utilize a functional genomics approach to uncover a comprehensive set of cellular restriction factors that inhibit rAAV-based transgene expression. Genetic inactivation of selected restriction factors increased rAAV transgene expression. Hence, modulation of identified restriction factors has the potential to enhance AAV gene replacement therapies.
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Affiliation(s)
- Ashley M. Ngo
- Chan Zuckerberg Biohub, San Francisco, California, USA
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3
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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: 32] [Impact Index Per Article: 16.0] [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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4
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Handyside B, Ismail AM, Zhang L, Yates B, Xie L, Sihn CR, Murphy R, Bouwman T, Kim CK, De Angelis R, Karim OA, McIntosh NL, Doss MX, Shroff S, Pungor E, Bhat VS, Bullens S, Bunting S, Fong S. Vector genome loss and epigenetic modifications mediate decline in transgene expression of AAV5 vectors produced in mammalian and insect cells. Mol Ther 2022; 30:3570-3586. [PMID: 36348622 PMCID: PMC9734079 DOI: 10.1016/j.ymthe.2022.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 11/03/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors are often produced in HEK293 or Spodoptera frugiperda (Sf)-based cell lines. We compared expression profiles of "oversized" (∼5,000 bp) and "standard-sized" (4,600 bp) rAAV5-human α1-antitrypsin (rAAV5-hA1AT) vectors manufactured in HEK293 or Sf cells and investigated molecular mechanisms mediating expression decline. C57BL/6 mice received 6 × 1013 vg/kg of vector, and blood and liver samples were collected through week 57. For all vectors, peak expression (weeks 12-24) declined by 50% to week 57. For Sf- and HEK293-produced oversized vectors, serum hA1AT was initially comparable, but in weeks 12-57, Sf vectors provided significantly higher expression. For HEK293 oversized vectors, liver genomes decreased continuously through week 57 and significantly correlated with A1AT protein. In RNA-sequencing analysis, HEK293 vector-treated mice had significantly higher inflammatory responses in liver at 12 weeks compared with Sf vector- and vehicle-treated mice. Thus, HEK293 vector genome loss led to decreased transgene protein. For Sf-produced vectors, genomes did not decrease from peak expression. Instead, vector genome accessibility significantly decreased from peak to week 57 and correlated with transgene RNA. Vector DNA interactions with active histone marks (H3K27ac/H3K4me3) were significantly reduced from peak to week 57, suggesting that epigenetic regulation impacts transgene expression of Sf-produced vectors.
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Affiliation(s)
- Britta Handyside
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | | | - Lening Zhang
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Bridget Yates
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Lin Xie
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Choong-Ryoul Sihn
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Ryan Murphy
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Taren Bouwman
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Chan Kyu Kim
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | | | - Omair A. Karim
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | | | | | - Shilpa Shroff
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Erno Pungor
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Vikas S. Bhat
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Sherry Bullens
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Stuart Bunting
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA
| | - Sylvia Fong
- BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA,Corresponding author: Sylvia Fong, BioMarin Pharmaceutical Inc., 105 Digital Drive, Novato, CA 94949, USA.
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5
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Hale BG. Antiviral immunity triggered by infection-induced host transposable elements. Curr Opin Virol 2021; 52:211-216. [PMID: 34959082 DOI: 10.1016/j.coviro.2021.12.006] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 12/06/2021] [Indexed: 12/13/2022]
Abstract
Host silencing of transposable elements (TEs) is critical to prevent genome damage and inappropriate inflammation. However, new evidence suggests that a virus-infected host may re-activate TEs and co-opt them for antiviral defense. RNA-Seq and specialized bioinformatics have revealed the diversity of virus infections that induce TEs. Furthermore, studies with influenza virus have uncovered how infection-triggered changes to the SUMOylation of TRIM28, an epigenetic co-repressor, lead to TE de-repression. Importantly, there is a growing appreciation of how de-repressed TEs stimulate antiviral gene expression, either via cis-acting enhancer functions or via their recognition as viral mimetics by innate immune nucleic acid sensors (e.g. RIG-I, mda-5 and cGAS). Understanding how viruses trigger, and counteract, TE-based antiviral immunity should provide insights into pathogenic mechanisms.
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Affiliation(s)
- Benjamin G Hale
- Institute of Medical Virology, University of Zurich, Winterthurerstrasse 190, Zurich, 8057, Switzerland.
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6
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Abstract
The single-stranded DNA genome of adeno-associated viruses (AAV) undergoes second-strand synthesis and transcription in the host cell nucleus. While wild-type AAV genomes are naturally silenced upon integration into the host genome, recombinant AAV (rAAV) genomes typically provide robust expression of transgenes persisting as extrachromosomal DNA or episomes. Episomal DNA associating with host histones are subject to epigenetic modifications, although the mechanisms underlying such are not well understood. Here, we provide evidence that the double-stranded DNA binding protein NP220, in association with the human silencing hub (HUSH) complex, mediates transcriptional silencing of single-stranded as well as self-complementary rAAV genomes. In cells lacking NP220 or other components of the HUSH complex, AAV genome transcript levels are increased and correlate with a marked reduction in repressive H3K9 histone methylation marks. We also provide evidence that the AAV capsid (serotype) can profoundly influence NP220-mediated mediated silencing of packaged genomes, indicating potential role(s) for capsid-genome or capsid-host factor interactions in regulating epigenetic silencing of rAAV genomes. Importance Recombinant AAV vectors can enable long term gene expression in a wide variety of tissues. However, transgene silencing has been reported in some human gene therapy clinical trials. Here, we demonstrate the human silencing hub (HUSH) complex can suppress transcript formation from rAAV vector genomes by epigenetic modification of associated host histones. Further, the AAV capsid appears to play an important role in this pathway. We postulate that modulation of epigenetic pathways could help improve rAAV expression.
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7
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Mattola S, Hakanen S, Salminen S, Aho V, Mäntylä E, Ihalainen TO, Kann M, Vihinen-Ranta M. Concepts to Reveal Parvovirus-Nucleus Interactions. Viruses 2021; 13:1306. [PMID: 34372512 PMCID: PMC8310053 DOI: 10.3390/v13071306] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 07/02/2021] [Indexed: 01/23/2023] Open
Abstract
Parvoviruses are small single-stranded (ss) DNA viruses, which replicate in the nucleoplasm and affect both the structure and function of the nucleus. The nuclear stage of the parvovirus life cycle starts at the nuclear entry of incoming capsids and culminates in the successful passage of progeny capsids out of the nucleus. In this review, we will present past, current, and future microscopy and biochemical techniques and demonstrate their potential in revealing the dynamics and molecular interactions in the intranuclear processes of parvovirus infection. In particular, a number of advanced techniques will be presented for the detection of infection-induced changes, such as DNA modification and damage, as well as protein-chromatin interactions.
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Affiliation(s)
- Salla Mattola
- Department of Biological and Environmental Science, University of Jyvaskyla, 40500 Jyvaskyla, Finland; (S.M.); (S.H.); (S.S.); (V.A.)
| | - Satu Hakanen
- Department of Biological and Environmental Science, University of Jyvaskyla, 40500 Jyvaskyla, Finland; (S.M.); (S.H.); (S.S.); (V.A.)
| | - Sami Salminen
- Department of Biological and Environmental Science, University of Jyvaskyla, 40500 Jyvaskyla, Finland; (S.M.); (S.H.); (S.S.); (V.A.)
| | - Vesa Aho
- Department of Biological and Environmental Science, University of Jyvaskyla, 40500 Jyvaskyla, Finland; (S.M.); (S.H.); (S.S.); (V.A.)
| | - Elina Mäntylä
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland; (E.M.); (T.O.I.)
| | - Teemu O. Ihalainen
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, 33520 Tampere, Finland; (E.M.); (T.O.I.)
| | - Michael Kann
- Department of Infectious Diseases, Institute of Biomedicine, Sahlgrenska Academy, University of Gothenburg, 41390 Gothenburg, Sweden;
- Department of Clinical Microbiology, Sahlgrenska University Hospital, 41345 Gothenburg, Sweden
| | - Maija Vihinen-Ranta
- Department of Biological and Environmental Science, University of Jyvaskyla, 40500 Jyvaskyla, Finland; (S.M.); (S.H.); (S.S.); (V.A.)
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8
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Maurer AC, Weitzman MD. Adeno-Associated Virus Genome Interactions Important for Vector Production and Transduction. Hum Gene Ther 2020; 31:499-511. [PMID: 32303138 PMCID: PMC7232694 DOI: 10.1089/hum.2020.069] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022] Open
Abstract
Recombinant adeno-associated virus has emerged as one of the most promising gene therapy delivery vectors. Development of these vectors took advantage of key features of the wild-type adeno-associated virus (AAV), enabled by basic studies of the underlying biology and requirements for transcription, replication, and packaging of the viral genome. Each step in generating and utilizing viral vectors involves numerous molecular interactions that together determine the efficiency of vector production and gene delivery. Once delivered into the cell, interactions with host proteins will determine the fate of the viral genome, and these will impact the intended goal of gene delivery. Here, we provide an overview of known interactions of the AAV genome with viral and cellular proteins involved in its amplification, packaging, and expression. Further appreciation of how the AAV genome interacts with host factors will enhance how this simple virus can be harnessed for an array of vector purposes that benefit human health.
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Affiliation(s)
- Anna C. Maurer
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Matthew D. Weitzman
- Division of Protective Immunity, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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9
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Siebels S, Czech-Sioli M, Spohn M, Schmidt C, Theiss J, Indenbirken D, Günther T, Grundhoff A, Fischer N. Merkel Cell Polyomavirus DNA Replication Induces Senescence in Human Dermal Fibroblasts in a Kap1/Trim28-Dependent Manner. mBio 2020; 11:e00142-20. [PMID: 32156811 PMCID: PMC7064754 DOI: 10.1128/mbio.00142-20] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Accepted: 01/29/2020] [Indexed: 12/16/2022] Open
Abstract
Merkel cell polyomavirus (MCPyV) is the only polyomavirus known to be associated with tumorigenesis in humans. Similarly to other polyomaviruses, MCPyV expresses a large tumor antigen (LT-Ag) that, together with a small tumor antigen (sT-Ag), contributes to cellular transformation and that is of critical importance for the initiation of the viral DNA replication. Understanding the cellular protein network regulated by MCPyV early proteins will significantly contribute to our understanding of the natural MCPyV life cycle as well as of the mechanisms by which the virus contributes to cellular transformation. We here describe KRAB-associated protein 1 (Kap1), a chromatin remodeling factor involved in cotranscriptional regulation, as a novel protein interaction partner of MCPyV T antigens sT and LT. Kap1 knockout results in a significant increase in the level of viral DNA replication that is highly suggestive of Kap1 being an important host restriction factor during MCPyV infection. Differently from other DNA viruses, MCPyV gene expression is unaffected in the absence of Kap1 and Kap1 does not associate with the viral genome. Instead, we show that in primary normal human dermal fibroblast (nHDF) cells, MCPyV DNA replication, but not T antigen expression alone, induces ataxia telangiectasia mutated (ATM) kinase-dependent Kap1 S824 phosphorylation, a mechanism that typically facilitates repair of double-strand breaks in heterochromatin by arresting the cells in G2 We show that MCPyV-induced inhibition of cell proliferation is mainly conferred by residues within the origin binding domain and thereby by viral DNA replication. Our data suggest that phosphorylation of Kap1 and subsequent Kap1-dependent G2 arrest/senescence represent host defense mechanisms against MCPyV replication in nHDF cells.IMPORTANCE We here describe Kap1 as a restriction factor in MCPyV infection. We report a novel, indirect mechanism by which Kap1 affects MCPyV replication. In contrast with from other DNA viruses, Kap1 does not associate with the viral genome in MCPyV infection and has no impact on viral gene expression. In MCPyV-infected nHDF cells, Kap1 phosphorylation (pKap1 S824) accumulates because of genomic stress mainly induced by viral DNA replication. In contrast, ectopic expression of LT or LT MCPyV mutants, previously shown to be important for induction of genotoxic stress, does not result in a similar extent of pKap1 accumulation. We show that cells actively replicating MCPyV accumulate pKap1 (in a manner dependent on the presence of ATM) and display a senescence phenotype reflected by G2 arrest. These results are supported by transcriptome analyses showing that LT antigen, in a manner dependent on the presence of Kap1, induces expression of secreted factors, which is known as the senescence-associated secretory phenotype (SASP).
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Affiliation(s)
- Svenja Siebels
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Manja Czech-Sioli
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Michael Spohn
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Claudia Schmidt
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Juliane Theiss
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Daniela Indenbirken
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Thomas Günther
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Adam Grundhoff
- Heinrich Pette Institute, Leibniz Institute for Experimental Virology, Hamburg, Germany
| | - Nicole Fischer
- Institute for Medical Microbiology, Virology and Hygiene, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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10
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Phosphatase Regulator NIPP1 Restrains Chemokine-Driven Skin Inflammation. J Invest Dermatol 2020; 140:1576-1588. [PMID: 31972250 DOI: 10.1016/j.jid.2020.01.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 12/20/2019] [Accepted: 01/05/2020] [Indexed: 02/06/2023]
Abstract
Nuclear inhibitor of protein phosphatase 1 (NIPP1) is a ubiquitously expressed nuclear protein that regulates functions of protein serine/threonine phosphatase-1 in cell proliferation and lineage specification. The role of NIPP1 in tissue homeostasis is not fully understood. This study shows that the selective deletion of NIPP1 in mouse epidermis resulted in epidermal hyperproliferation, a reduced adherence of basal keratinocytes, and a gradual decrease in the stemness of hair follicle stem cells, culminating in hair loss. This complex phenotype was associated with chronic sterile skin inflammation and could be partially rescued by dexamethasone treatment. NIPP1-deficient keratinocytes massively expressed proinflammatory chemokines and immunomodulatory proteins in a cell-autonomous manner. Chemokines subsequently induced the recruitment and activation of immune cells, in particular conventional dendritic cells and Langerhans cells, accounting for the chronic inflammation phenotype. The data identifies NIPP1 as a key regulator of epidermal homeostasis and as a potential target for the treatment of inflammatory skin diseases.
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11
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Methylation Status of the Adeno-Associated Virus Type 2 (AAV2). Viruses 2019; 11:v11010038. [PMID: 30634383 PMCID: PMC6356613 DOI: 10.3390/v11010038] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 01/04/2019] [Accepted: 01/04/2019] [Indexed: 11/16/2022] Open
Abstract
To analyze the methylation status of wild-type adeno-associated virus type 2 (AAV2), bisulfite PCR sequencing (BPS) of the packaged viral genome and its integrated form was performed and 262 of the total 266 CG dinucleotides (CpG) were mapped. In virion-packaged DNA, the ratio of the methylated cytosines ranged between 0⁻1.7%. In contrast, the chromosomally integrated AAV2 genome was hypermethylated with an average of 76% methylation per CpG site. The methylation level showed local minimums around the four known AAV2 promoters. To study the effect of methylation on viral rescue and replication, the replication initiation capability of CpG methylated and non-CpG methylated AAV DNA was compared. The in vitro hypermethylation of the viral genome does not inhibit its rescue and replication from a plasmid transfected into cells. This insensitivity of the viral replicative machinery to methylation may permit the rescue of the integrated heavily methylated AAV genome from the host's chromosomes.
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Ferreira M, Beullens M, Bollen M, Van Eynde A. Functions and therapeutic potential of protein phosphatase 1: Insights from mouse genetics. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2019; 1866:16-30. [PMID: 30056088 PMCID: PMC7114192 DOI: 10.1016/j.bbamcr.2018.07.019] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 07/16/2018] [Accepted: 07/19/2018] [Indexed: 02/07/2023]
Abstract
Protein phosphatase 1 (PP1) catalyzes more than half of all phosphoserine/threonine dephosphorylation reactions in mammalian cells. In vivo PP1 does not exist as a free catalytic subunit but is always associated with at least one regulatory PP1-interacting protein (PIP) to generate a large set of distinct holoenzymes. Each PP1 complex controls the dephosphorylation of only a small subset of PP1 substrates. We screened the literature for genetically engineered mouse models and identified models for all PP1 isoforms and 104 PIPs. PP1 itself and at least 49 PIPs were connected to human disease-associated phenotypes. Additionally, phenotypes related to 17 PIPs were clearly linked to altered PP1 function, while such information was lacking for 32 other PIPs. We propose structural reverse genetics, which combines structural characterization of proteins with mouse genetics, to identify new PP1-related therapeutic targets. The available mouse models confirm the pleiotropic action of PP1 in health and diseases.
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Affiliation(s)
- Mónica Ferreira
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Monique Beullens
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Mathieu Bollen
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium
| | - Aleyde Van Eynde
- Laboratory of Biosignaling & Therapeutics, KU Leuven Department of Cellular and Molecular Medicine, University of Leuven, B-3000 Leuven, Belgium.
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