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Catalán-Tatjer D, Tzimou K, Nielsen LK, Lavado-García J. Unravelling the essential elements for recombinant adeno-associated virus (rAAV) production in animal cell-based platforms. Biotechnol Adv 2024; 73:108370. [PMID: 38692443 DOI: 10.1016/j.biotechadv.2024.108370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 04/05/2024] [Accepted: 04/27/2024] [Indexed: 05/03/2024]
Abstract
Recombinant adeno-associated viruses (rAAVs) stand at the forefront of gene therapy applications, holding immense significance for their safe and efficient gene delivery capabilities. The constantly increasing and unmet demand for rAAVs underscores the need for a more comprehensive understanding of AAV biology and its impact on rAAV production. In this literature review, we delved into AAV biology and rAAV manufacturing bioprocesses, unravelling the functions and essentiality of proteins involved in rAAV production. We discuss the interconnections between these proteins and how they affect the choice of rAAV production platform. By addressing existing inconsistencies, literature gaps and limitations, this review aims to define a minimal set of genes that are essential for rAAV production, providing the potential to advance rAAV biomanufacturing, with a focus on minimizing the genetic load within rAAV-producing cells.
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Affiliation(s)
- David Catalán-Tatjer
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Konstantina Tzimou
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark
| | - Lars K Nielsen
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark; Australian Institute for Bioengineering and Nanotechnology, University of Queensland, Australia
| | - Jesús Lavado-García
- The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Denmark.
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2
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Pierce GF, Fong S, Long BR, Kaczmarek R. Deciphering conundrums of adeno-associated virus liver-directed gene therapy: focus on hemophilia. J Thromb Haemost 2024; 22:1263-1289. [PMID: 38103734 DOI: 10.1016/j.jtha.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/07/2023] [Accepted: 12/01/2023] [Indexed: 12/19/2023]
Abstract
Adeno-associated virus gene therapy has been the subject of intensive investigation for monogenic disease gene addition therapy for more than 25 years, yet few therapies have been approved by regulatory agencies. Most have not progressed beyond phase 1/2 due to toxicity, lack of efficacy, or both. The liver is a natural target for adeno-associated virus since most serotypes have a high degree of tropism for hepatocytes due to cell surface receptors for the virus and the unique liver sinusoidal geometry facilitating high volumes of blood contact with hepatocyte cell surfaces. Recessive monogenic diseases such as hemophilia represent promising targets since the defective proteins are often synthesized in the liver and secreted into the circulation, making them easy to measure, and many do not require precise regulation. Yet, despite initiation of many disease-specific clinical trials, therapeutic windows are often nonexistent, resulting in excess toxicity and insufficient efficacy. Iterative progress built on these attempts is best illustrated by hemophilia, with the first regulatory approvals for factor IX and factor VIII gene therapies eventually achieved 25 years after the first gene therapy studies in humans. Although successful gene transfer may result in the production of sufficient transgenic protein to modify the disease, many emerging questions on durability, predictability, reliability, and variability of response have not been answered. The underlying biology accounting for these heterogeneous responses and the interplay between host and virus is the subject of intense investigation and the subject of this review.
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Affiliation(s)
- Glenn F Pierce
- World Federation of Hemophilia, Montreal, Quebec, Canada.
| | - Sylvia Fong
- BioMarin Pharmaceutical Inc, Research and Early Development, Novato, California, USA
| | - Brian R Long
- BioMarin Pharmaceutical Inc, Research and Early Development, Novato, California, USA
| | - Radoslaw Kaczmarek
- Department of Pediatrics, Indiana University School of Medicine, Wells Center for Pediatric Research, Indiana, USA; Laboratory of Glycobiology, Hirszfeld Institute of Immunology and Experimental Therapy, Wroclaw, Poland
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3
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Hoad M, Roby JA, Forwood JK. Structural basis for nuclear import of bat adeno-associated virus capsid protein. J Gen Virol 2024; 105:001960. [PMID: 38441555 PMCID: PMC10999750 DOI: 10.1099/jgv.0.001960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Accepted: 01/22/2024] [Indexed: 03/07/2024] Open
Abstract
Adeno-associated viruses (AAV) are one of the world's most promising gene therapy vectors and as a result, are one of the most intensively studied viral vectors. Despite a wealth of research into these vectors, the precise characterisation of AAVs to translocate into the host cell nucleus remains unclear. Recently we identified the nuclear localization signals of an AAV porcine strain and determined its mechanism of binding to host importin proteins. To expand our understanding of diverse AAV import mechanisms we sought to determine the mechanism in which the Cap protein from a bat-infecting AAV can interact with transport receptor importins for translocation into the nucleus. Using a high-resolution crystal structure and quantitative assays, we were able to not only determine the exact region and residues of the N-terminal domain of the Cap protein which constitute the functional NLS for binding with the importin alpha two protein, but also reveal the differences in binding affinity across the importin-alpha isoforms. Collectively our results allow for a detailed molecular view of the way AAV Cap proteins interact with host proteins for localization into the cell nucleus.
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Affiliation(s)
- Mikayla Hoad
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Justin A. Roby
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
- Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
| | - Jade K. Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
- Gulbali Institute, Charles Sturt University, Wagga Wagga, NSW, 2678, Australia
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4
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Slack J, Nguyen C, Ibe-Enwo A. A Lac Repressor-Inducible Baculovirus Expression Vector for Controlling Adeno-Associated Virus Capsid Ratios. Viruses 2023; 16:51. [PMID: 38257750 PMCID: PMC10820722 DOI: 10.3390/v16010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 12/19/2023] [Accepted: 12/23/2023] [Indexed: 01/24/2024] Open
Abstract
The baculovirus expression vector (BEV) system is an efficient, cost-effective, and scalable method to produce recombinant adeno-associated virus (rAAV) gene therapy vectors. Most BEV designs emulate the wild-type AAV transcriptome and translate the AAV capsid proteins, VP1, VP2, and VP3, from a single mRNA transcript with three overlapping open reading frames (ORFs). Non-canonical translation initiation codons for VP1 and VP2 reduce their abundances relative to VP3. Changing capsid ratios to improve rAAV vector efficacy requires a theoretical modification of the translational context. We have developed a Lac repressor-inducible system to empirically regulate the expression of VP1 and VP2 proteins relative to VP3 in the context of the BEV. We demonstrate the use of this system to tune the abundance, titer, and potency of a neurospecific rAAV9 serotype derivative. VP1:VP2:VP3 ratios of 1:1:8 gave optimal potency for this rAAV. It was discovered that the ratios of capsid proteins expressed were different than the ratios that ultimately were in purified capsids. Overexpressed VP1 did not become incorporated into capsids, while overexpressed VP2 did. Overabundance of VP2 correlated with reduced rAAV titers. This work demonstrates a novel technology for controlling the production of rAAV in the BEV system and shows a new perspective on the biology of rAAV capsid assembly.
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Affiliation(s)
- Jeffrey Slack
- Voyager Therapeutics, 64 Sidney St., Cambridge, MA 02139, USA;
| | | | - Amanda Ibe-Enwo
- Voyager Therapeutics, 64 Sidney St., Cambridge, MA 02139, USA;
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5
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De BP, Cram S, Lee H, Rosenberg JB, Sondhi D, Crystal RG, Kaminsky SM. Assessment of Residual Full-Length SV40 Large T Antigen in Clinical-Grade Adeno-Associated Virus Vectors Produced in 293T Cells. Hum Gene Ther 2023; 34:697-704. [PMID: 37171121 PMCID: PMC10457653 DOI: 10.1089/hum.2023.032] [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: 02/28/2023] [Accepted: 05/06/2023] [Indexed: 05/13/2023] Open
Abstract
Efficient production of adeno-associated virus (AAV) vectors is a significant challenge. Human embryonic kidney HEK293T cells are widely used in good manufacturing practice facilities, producing higher yield of AAV vectors for clinical applications than HEK293 through the addition of a constitutive expression of SV40 large T antigen (SV40T), which stimulates Rep expression. However, the theoretical potential for tumorigenic consequences of a clinical AAV product containing residual DNA encoding SV40T, which may inhibit p53 growth suppressive functions is a safety concern. Although the risk is theoretical, to assure a low risk/high confidence of safety for clinical drug development, we have established a sensitive assay for assessment of functional full-length transcription competent SV40T DNA in HEK293T cell-produced AAV vectors. Using HEK293T generated 8, 9, and rh.10 serotype AAV vectors, the presence of SV40T in purified vector was assessed in vitro using quantitative polymerase chain reaction (qPCR) targeting a 129 bp amplicon combined with nested PCR targeting full-length SV40T DNA. Although low levels of the smaller amplicon were present in each AAV serotype, the full-length SV40T was undetectable. No transcription competent full-length SV40T DNA was observed by reverse transcription-quantitative polymerase chain reaction using an in vivo amplification of signal in mouse liver administered (2-10 × 1010 gc) 129 bp amplicon-positive AAV vectors. As a control for gene transfer, high levels of expressed transgene mRNAs were observed from each serotype AAV vector, yet, SV40T mRNA was undetectable. In vivo assessment of these three liver-tropic AAV serotypes, each with amplicon-positive qPCR SV40T DNA, demonstrated high transgene mRNA expression but no SV40T mRNA, that is, detection of small segments of SV40T DNA in 293T cell produced AAV inappropriately leads to the conclusion of residuals with the potential to express SV40T. This sensitive assay can be used to assess the level, if any, of SV40T antigen contaminating AAV vectors generated by HEK293T cells. ClinicalTrials.gov identifier: NCT03634007; NCT05302271; NCT01414985; NCT01161576.
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Affiliation(s)
- Bishnu P. De
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Sara Cram
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Hyunmi Lee
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
| | | | - Dolan Sondhi
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Ronald G. Crystal
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
| | - Stephen M. Kaminsky
- Department of Genetic Medicine, Weill Cornell Medicine, New York, New York, USA
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6
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Ning K, Kuz CA, Cheng F, Feng Z, Yan Z, Qiu J. Adeno-Associated Virus Monoinfection Induces a DNA Damage Response and DNA Repair That Contributes to Viral DNA Replication. mBio 2023; 14:e0352822. [PMID: 36719192 PMCID: PMC9973366 DOI: 10.1128/mbio.03528-22] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/03/2023] [Indexed: 02/01/2023] Open
Abstract
Adeno-associated virus (AAV) belongs to the Dependoparvovirus genus of the Parvoviridae family. AAV replication relies on a helper virus, such as adenovirus (Ad). Co-infection of AAV and Ad induces a DNA damage response (DDR), although its function in AAV DNA replication remains unknown. In this study, monoinfection of AAV2 in HEK293T cells expressing a minimal set of Ad helper genes was used to investigate the role of the DDR solely induced by AAV. We found that AAV2 DNA replication, but not single stranded (ss)DNA genome accumulation and Rep expression only, induced a robust DDR in HEK293T cells. The induced DDR featured the phosphorylation of replication protein A32 (RPA32), histone variant H2AX (H2A histone family member X), and all 3 phosphatidylinositol 3-kinase-related kinases (PIKKs). We also found that the kinase ataxia telangiectasia and Rad3-related protein (ATR) plays a major role in AAV2 DNA replication and that Y family DNA repair DNA polymerases η (Pol η) and Pol κ contribute to AAV2 DNA replication both in vitro and in HEK293T cells. Knockout of Pol η and Pol κ in HEK293T cells significantly decreased wild-type AAV2 replication and recombinant AAV2 production. Thus, our study has proven that AAV2 DNA replication induces a DDR, which in turn initiates a DNA repairing process that partially contributes to the viral genome amplification in HEK293T cells. IMPORTANCE Recombinant AAV (rAAV) has emerged as one of the preferred delivery vectors for clinical gene therapy. rAAV production in HEK293 cells by transfection of a rAAV transgene plasmid, an AAV Rep and Cap expression packaging plasmid, and an Ad helper plasmid remains the popular method. Here, we demonstrated that the high fidelity Y family DNA repair DNA polymerase, Pol η, and Pol κ, plays a significant role in AAV DNA replication and rAAV production in HEK293T cells. Understanding the AAV DNA replication mechanism in HEK293T cells could provide clues to increase rAAV vector yield produced from the transfection method. We also provide evidence that the ATR-mediated DNA repair process through Pol η and Pol κ is one of the mechanisms to amplify AAV genome, which could explain AAV replication and rAAV ssDNA genome conversion in mitotic quiescent cells.
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Affiliation(s)
- Kang Ning
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Cagla Aksu Kuz
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Fang Cheng
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Zehua Feng
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa, USA
| | - Ziying Yan
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa, USA
| | - Jianming Qiu
- Department of Microbiology, Molecular Genetics and Immunology, University of Kansas Medical Center, Kansas City, Kansas, USA
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Hoad M, Cross EM, Donnelly CM, Sarker S, Roby JA, Forwood JK. Structural Characterization of Porcine Adeno-Associated Virus Capsid Protein with Nuclear Trafficking Protein Importin Alpha Reveals a Bipartite Nuclear Localization Signal. Viruses 2023; 15:v15020315. [PMID: 36851528 PMCID: PMC9964314 DOI: 10.3390/v15020315] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 01/11/2023] [Accepted: 01/17/2023] [Indexed: 01/24/2023] Open
Abstract
Adeno-associated viruses (AAV) are important vectors for gene therapy, and accordingly, many aspects of their cell transduction pathway have been well characterized. However, the specific mechanisms that AAV virions use to enter the host nucleus remain largely unresolved. We therefore aimed to reveal the interactions between the AAV Cap protein and the nuclear transport protein importin alpha (IMPα) at an atomic resolution. Herein we expanded upon our earlier research into the Cap nuclear localization signal (NLS) of a porcine AAV isolate, by examining the influence of upstream basic regions (BRs) towards IMPα binding. Using a high-resolution crystal structure, we identified that the IMPα binding determinants of the porcine AAV Cap comprise a bipartite NLS with an N-terminal BR binding at the minor site of IMPα, and the previously identified NLS motif binding at the major site. Quantitative assays showed a vast difference in binding affinity between the previously determined monopartite NLS, and bipartite NLS described in this study. Our results provide a detailed molecular view of the interaction between AAV capsids and the nuclear import receptor, and support the findings that AAV capsids enter the nucleus by binding the nuclear import adapter IMPα using the classical nuclear localization pathway.
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Affiliation(s)
- Mikayla Hoad
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Emily M. Cross
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Camilla M. Donnelly
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Subir Sarker
- Department of Microbiology, Anatomy, Physiology and Pharmacology, School of Agriculture, Biomedicine and Environment, La Trobe University, Melbourne, VIC 3086, Australia
| | - Justin A. Roby
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
| | - Jade K. Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW 2678, Australia
- Correspondence:
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Stolte B, Schreiber-Katz O, Günther R, Wurster C, Petri S, Osmanovic A, Freigang M, Uzelac Z, Leo M, von Velsen O, Bayer W, Dittmer U, Kleinschnitz C, Hagenacker T. Prevalence of Anti-AAV9 Antibodies in Adult Patients with Spinal Muscular Atrophy. Hum Gene Ther 2022; 33:968-976. [PMID: 35943879 DOI: 10.1089/hum.2022.054] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
5q-associated spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disorder that leads to progressive muscle atrophy and weakness. The disease is caused by a homozygous deletion or mutation in the survival of motor neuron 1 gene (SMN1), resulting in insufficient levels of SMN protein. Onasemnogene abeparvovec-xioi (OA) is a non-replicating vector based on adeno-associated virus serotype 9 (AAV9) that contains the full-length human SMN1 gene. Recently, OA was approved for the treatment of SMA by the U.S. Food and Drug Administration and the European Medicines Agency. Since the presence of neutralizing antibodies caused by previous natural exposure to wild-type AAVs may impair the efficiency of AAV-mediated gene transfer, and thus reduce the therapeutic benefit of the gene therapy, an AAV9-binding antibody titer of >1:50 was defined as a surrogate exclusion criterion in pivotal OA clinical trials. However, these studies were exclusively conducted in infants and children. Since data on anti-AAV9 antibody titers in adults are generally sparse and not available for adult patients with SMA, we determined the prevalence of anti-AAV9 antibodies in sera of adult individuals with SMA to evaluate the feasibility of AAV9-mediated gene therapy in this cohort. In our study population of 69 adult patients with SMA type 2 and type 3 from four German academic sites, only three patients (4.3%) had an elevated anti-AAV9 antibody titer of >1:50. The prevalence of anti-AAV9 antibodies did not increase with age. The low and age-independent prevalence of anti-AAV9 antibodies in our cohort provides evidence that gene therapy with intravenous administered recombinant AAV9 vectors (rAAV9) might be feasible in adult patients with SMA, regardless of the patients' sex, SMA type, walking ability, or ventilatory status. This could also apply to the treatment of other inherited neurological diseases with rAAV9.
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Affiliation(s)
- Benjamin Stolte
- University Medicine Essen, Dep of Neurology, Essen, Germany;
| | | | - René Günther
- Dresden University Hospital, Department of Neurology, Dresden, Sachsen, Germany;
| | - Claudia Wurster
- RKU, Department of Neurology, Ulm, Baden-Württemberg, Germany;
| | - Susanne Petri
- MHH, Department of Neurology, Hannover, Niedersachsen, Germany;
| | - Alma Osmanovic
- University Medicine Essen, 8Essen Center for Rare Diseases (EZSE), Essen, Germany.,MHH, Department of Neurology, Hannover, Niedersachsen, Germany;
| | - Maren Freigang
- Dresden University Hospital, Department of Neurology, Dresden, Sachsen, Germany;
| | - Zeljko Uzelac
- RKU, Department of Neurology, Ulm, Baden-Württemberg, Germany;
| | - Markus Leo
- University Medicine Essen, Dep of Neurology, Essen, Germany;
| | - Otgonzul von Velsen
- University Medicine Essen, Institute for Medical Informatics, Biometrics and Epidemiology, Essen, Germany;
| | - Wibke Bayer
- University Medicine Essen, Institute for Virology, Essen, Germany;
| | - Ulf Dittmer
- University Medicine Essen, Institute for Virology, Essen, Germany;
| | | | - Tim Hagenacker
- University Medicine Essen, Dep of Neurology, Hufelandstr. 55, Essen, Germany, 45127;
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9
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Gupta M. Parvovirus Vectors: The Future of Gene Therapy. Vet Med Sci 2022. [DOI: 10.5772/intechopen.105085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The unique diversity of parvoviral vectors with innate antioncogenic properties, autonomous replication, ease of recombinant vector production and stable transgene expression in target cells makes them an attractive choice as viral vectors for gene therapy protocols. Amongst various parvoviruses that have been identified so far, recombinant vectors originating from adeno-associated virus, minute virus of mice (MVM), LuIII and parvovirus H1 have shown promising results in many preclinical models of human diseases including cancer. The adeno-associated virus (AAV), a non-pathogenic human parvovirus, has gained attention as a potentially useful vector. The improved understanding of the metabolism of vector genomes and the mechanism of transduction by AAV vectors is leading to advancement in the development of more sophisticated AAV vectors. The in-depth studies of AAV vector biology is opening avenues for more robust design of AAV vectors that have potentially increased transduction efficiency, increased specificity in cellular targeting, and an increased payload capacity. This chapter gives an overview of the application of autonomous parvoviral vectors and AAV vectors, based on our current understanding of viral biology and the state of the platform.
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10
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Hoad M, Roby JA, Forwood JK. Structural characterization of the porcine adeno-associated virus Po1 capsid protein binding to the nuclear trafficking protein importin alpha. FEBS Lett 2021; 595:2793-2804. [PMID: 34661283 DOI: 10.1002/1873-3468.14209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 11/05/2022]
Abstract
Adeno-associated viruses (AAVs) are key vectors for gene therapy; thus, many aspects of their cell transduction pathway have been revealed in detail. However, the specific mechanisms AAV virions use to enter the host nucleus remain largely unresolved. We therefore aimed to reveal the structural interactions between the AAV capsid (Cap) protein and the nuclear transport protein importin alpha (IMPα). A putative nuclear localization sequence (NLS) in the virion protein 1 capsid protein of the porcine AAV Po1 was identified. This region was complexed with IMPα and a structure solved at 2.26 Å. This is the first time that an NLS of AAV Cap complexed with IMPα has been determined structurally. Our results support the findings that AAV capsids enter the nucleus through binding the nuclear import adapter IMPα.
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Affiliation(s)
- Mikayla Hoad
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Justin A Roby
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
| | - Jade K Forwood
- School of Dentistry and Medical Sciences, Charles Sturt University, Wagga Wagga, NSW, Australia
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11
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Bastola P, Song L, Gilger BC, Hirsch ML. Adeno-Associated Virus Mediated Gene Therapy for Corneal Diseases. Pharmaceutics 2020; 12:pharmaceutics12080767. [PMID: 32823625 PMCID: PMC7464341 DOI: 10.3390/pharmaceutics12080767] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/05/2020] [Accepted: 08/06/2020] [Indexed: 12/14/2022] Open
Abstract
According to the World Health Organization, corneal diseases are the fourth leading cause of blindness worldwide accounting for 5.1% of all ocular deficiencies. Current therapies for corneal diseases, which include eye drops, oral medications, corrective surgeries, and corneal transplantation are largely inadequate, have undesirable side effects including blindness, and can require life-long applications. Adeno-associated virus (AAV) mediated gene therapy is an optimistic strategy that involves the delivery of genetic material to target human diseases through gene augmentation, gene deletion, and/or gene editing. With two therapies already approved by the United States Food and Drug Administration and 200 ongoing clinical trials, recombinant AAV (rAAV) has emerged as the in vivo viral vector-of-choice to deliver genetic material to target human diseases. Likewise, the relative ease of applications through targeted delivery and its compartmental nature makes the cornea an enticing tissue for AAV mediated gene therapy applications. This current review seeks to summarize the development of AAV gene therapy, highlight preclinical efficacy studies, and discuss potential applications and challenges of this technology for targeting corneal diseases.
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Affiliation(s)
- Prabhakar Bastola
- Ophthalmology, University of North Carolina, Chapel Hill, NC 27599, USA; (P.B.); (L.S.); (B.C.G.)
- Gene Therapy Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Liujiang Song
- Ophthalmology, University of North Carolina, Chapel Hill, NC 27599, USA; (P.B.); (L.S.); (B.C.G.)
- Gene Therapy Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Brian C. Gilger
- Ophthalmology, University of North Carolina, Chapel Hill, NC 27599, USA; (P.B.); (L.S.); (B.C.G.)
- Clinical Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Matthew L. Hirsch
- Ophthalmology, University of North Carolina, Chapel Hill, NC 27599, USA; (P.B.); (L.S.); (B.C.G.)
- Gene Therapy Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Correspondence: ; Tel.: +1-919-966-0696
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12
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Meier AF, Fraefel C, Seyffert M. The Interplay between Adeno-Associated Virus and its Helper Viruses. Viruses 2020; 12:v12060662. [PMID: 32575422 PMCID: PMC7354565 DOI: 10.3390/v12060662] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 12/14/2022] Open
Abstract
The adeno-associated virus (AAV) is a small, nonpathogenic parvovirus, which depends on helper factors to replicate. Those helper factors can be provided by coinfecting helper viruses such as adenoviruses, herpesviruses, or papillomaviruses. We review the basic biology of AAV and its most-studied helper viruses, adenovirus type 5 (AdV5) and herpes simplex virus type 1 (HSV-1). We further outline the direct and indirect interactions of AAV with those and additional helper viruses.
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13
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Ronzitti G, Gross DA, Mingozzi F. Human Immune Responses to Adeno-Associated Virus (AAV) Vectors. Front Immunol 2020; 11:670. [PMID: 32362898 PMCID: PMC7181373 DOI: 10.3389/fimmu.2020.00670] [Citation(s) in RCA: 178] [Impact Index Per Article: 44.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 03/24/2020] [Indexed: 12/24/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors are one of the most promising in vivo gene delivery tools. Several features make rAAV vectors an ideal platform for gene transfer. However, the high homology with the parental wild-type virus, which often infects humans, poses limitations in terms of immune responses associated with this vector platform. Both humoral and cell-mediated immunity to wild-type AAV have been documented in healthy donors, and, at least in the case of anti-AAV antibodies, have been shown to have a potentially high impact on the outcome of gene transfer. While several factors can contribute to the overall immunogenicity of rAAV vectors, vector design and the total vector dose appear to be responsible of immune-mediated toxicities. While preclinical models have been less than ideal in predicting the outcome of gene transfer in humans, the current preclinical body of evidence clearly demonstrates that rAAV vectors can trigger both innate and adaptive immune responses. Data gathered from clinical trials offers key learnings on the immunogenicity of AAV vectors, highlighting challenges as well as the potential strategies that could help unlock the full therapeutic potential of in vivo gene transfer.
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Affiliation(s)
- Giuseppe Ronzitti
- INTEGRARE, Genethon, Inserm, Univ Evry, Université Paris-Saclay, Evry, France
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Verdera HC, Kuranda K, Mingozzi F. AAV Vector Immunogenicity in Humans: A Long Journey to Successful Gene Transfer. Mol Ther 2020; 28:723-746. [PMID: 31972133 PMCID: PMC7054726 DOI: 10.1016/j.ymthe.2019.12.010] [Citation(s) in RCA: 335] [Impact Index Per Article: 83.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Accepted: 12/27/2019] [Indexed: 12/15/2022] Open
Abstract
Gene therapy with adeno-associated virus (AAV) vectors has demonstrated safety and long-term efficacy in a number of trials across target organs, including eye, liver, skeletal muscle, and the central nervous system. Since the initial evidence that AAV vectors can elicit capsid T cell responses in humans, which can affect the duration of transgene expression, much progress has been made in understanding and modulating AAV vector immunogenicity. It is now well established that exposure to wild-type AAV results in priming of the immune system against the virus, with development of both humoral and T cell immunity. Aside from the neutralizing effect of antibodies, the impact of pre-existing immunity to AAV on gene transfer is still poorly understood. Herein, we review data emerging from clinical trials across a broad range of gene therapy applications. Common features of immune responses to AAV can be found, suggesting, for example, that vector immunogenicity is dose-dependent, and that innate immunity plays an important role in the outcome of gene transfer. A range of host-specific factors are also likely to be important, and a comprehensive understanding of the mechanisms driving AAV vector immunogenicity in humans will be key to unlocking the full potential of in vivo gene therapy.
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Affiliation(s)
- Helena Costa Verdera
- Genethon and INSERM U951, 91000 Evry, France; Sorbonne Université and INSERM U974, 75013 Paris, France
| | | | - Federico Mingozzi
- Genethon and INSERM U951, 91000 Evry, France; Spark Therapeutics, Philadelphia, PA 19104, USA.
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The interaction of human papillomaviruses and adeno-associated viruses in suppressive co-infections. INFECTION GENETICS AND EVOLUTION 2019; 73:66-70. [PMID: 31026603 DOI: 10.1016/j.meegid.2019.04.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 03/05/2019] [Accepted: 04/19/2019] [Indexed: 02/07/2023]
Abstract
Human papillomavirus (HPV) is one of the most common oncogenic viruses which cause malignancy in different epithelial surfaces of the human body and its infection is the main cause of cervical cancer. However, research suggests that this virus might not be the sole cause of infection in target cells. It is believed that, other infectious agents could co-infect the same cell with HPV including; bacteria, viruses, and parasites, which may have different effects on the carcinogenesis of HPV infections. One of the most important viruses is adeno-associated virus (AAV), which comes from the parvoviridae family. The function of this virus is associated with several stages of HPV carcinogenicity, which leads to the suppression of HPV oncogenesis. The inhibition effects of AAV are exerted not only in viral parts but also in cellular parts. This suppression illuminates a new therapeutic approach in the way of HPV-associated cervical cancer. In the present review we consider the exact roles of AAV infection in this suppression.
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Hagedorn C, Schnödt-Fuchs M, Boehme P, Abdelrazik H, Lipps HJ, Büning H. S/MAR Element Facilitates Episomal Long-Term Persistence of Adeno-Associated Virus Vector Genomes in Proliferating Cells. Hum Gene Ther 2017; 28:1169-1179. [PMID: 28665147 DOI: 10.1089/hum.2017.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Adeno-associated virus (AAV) vectors are one of the most frequently applied gene transfer systems in research and human clinical trials. Since AAV vectors do not possess an integrase activity, application is restricted to terminally differentiated tissues if transgene expression is required long term. To overcome this limitation and to generate AAV vectors that persist episomally in dividing cells, AAV vector genomes were equipped with a scaffold/matrix attachment region (S/MAR). After a mild antibiotic selection, cells transduced with AAV-S/MAR established colonies that maintained long-term transgene expression (>50 population doublings) from replicating AAV vector episomes in the absence of further selection. Unexpectedly, with a lesser but still significant efficiency, the control vector (AAV-ΔS/MAR), a standard single-stranded AAV vector, also established stable transgene-expressing colonies, most of which were maintained as replicating episomes rather than integrated vector genomes. Thus, based on the result in HeLa cells, it is concluded that AAV vector genomes per se possess the ability to establish episomal maintenance in proliferating cells, a feature that can be enhanced by incorporation of a foreign genomic element such as an S/MAR element.
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Affiliation(s)
- Claudia Hagedorn
- 1 Institute of Cell Biology, ZBAF, University of Witten/Herdecke , Witten, Germany
| | - Maria Schnödt-Fuchs
- 2 Laboratory for AAV Vector Development, Center for Molecular Medicine Cologne (CMMC), University of Cologne , Cologne, Germany .,3 Department I of Internal Medicine, University Hospital Cologne , Cologne, Germany .,4 German Center for Infection Research (DZIF) , partner sites Bonn-Cologne and Hannover-Braunschweig
| | - Philip Boehme
- 1 Institute of Cell Biology, ZBAF, University of Witten/Herdecke , Witten, Germany .,5 Institute of Virology and Microbiology, ZBAF, University of Witten/Herdecke , Witten, Germany
| | - Heba Abdelrazik
- 2 Laboratory for AAV Vector Development, Center for Molecular Medicine Cologne (CMMC), University of Cologne , Cologne, Germany .,6 Clinical Pathology Department, Faculty of Medicine, Cairo University , Cairo, Egypt
| | - Hans J Lipps
- 1 Institute of Cell Biology, ZBAF, University of Witten/Herdecke , Witten, Germany
| | - Hildegard Büning
- 2 Laboratory for AAV Vector Development, Center for Molecular Medicine Cologne (CMMC), University of Cologne , Cologne, Germany .,3 Department I of Internal Medicine, University Hospital Cologne , Cologne, Germany .,4 German Center for Infection Research (DZIF) , partner sites Bonn-Cologne and Hannover-Braunschweig.,7 Laboratory for Infection Biology and Gene Transfer, Institute of Experimental Hematology, Hannover Medical School , Hannover, Germany
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Abstract
AAV has been studied for 55 years and has been developed as a vector for about 35 years. By now, there is a fairly good idea of the dimensions of what would be useful to know to employ AAV optimally as a vector, but there are still many unanswered questions within the system. As with all biological systems, each good experiment raises further questions to answer. This article provides an overview of those areas in which unknown information can be identified and of those questions that have not yet been recognized. Some of these are touched on in the six review articles in this issue of Human Gene Therapy.
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Affiliation(s)
- Kenneth I Berns
- Guest Co-Editors, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine , Gainesville, Florida
| | - Nicholas Muzyczka
- Guest Co-Editors, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine , Gainesville, Florida
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Moore AR, Dong B, Chen L, Xiao W. Vaccinia virus as a subhelper for AAV replication and packaging. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15044. [PMID: 26636113 PMCID: PMC4650997 DOI: 10.1038/mtm.2015.44] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 10/02/2015] [Accepted: 10/05/2015] [Indexed: 11/30/2022]
Abstract
Adeno-associated virus (AAV) has been widely used as a gene therapy vector to treat a variety of disorders. While these vectors are increasingly popular and successful in the clinic, there is still much to learn about the viruses. Understanding the biology of these viruses is essential in engineering better vectors and generating vectors more efficiently for large-scale use. AAV requires a helper for production and replication making this aspect of the viral life cycle crucial. Vaccinia virus (VV) has been widely cited as a helper virus for AAV. However, to date, there are no detailed analyses of its helper function. Here, the helper role of VV was studied in detail. In contrast to common belief, we demonstrated that VV was not a sufficient helper virus for AAV replication. Vaccinia failed to produce rAAV and activate AAV promoters. While this virus could not support rAAV production, Vaccinia could initiate AAV replication and packaging when AAV promoter activation is not necessary. This activity is due to the ability of Vaccinia-driven Rep78 to transcribe in the cytoplasm and subsequently translate in the nucleus and undergo typical functions in the AAV life cycle. As such, VV is subhelper for AAV compared to complete helper functions of adenovirus.
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Affiliation(s)
- Andrea R Moore
- Department of Microbiology and Immunology, Sol Sherry Thrombosis Research Center, Temple University , Philadelphia, Pennsylvania, USA
| | - Biao Dong
- Department of Microbiology and Immunology, Sol Sherry Thrombosis Research Center, Temple University , Philadelphia, Pennsylvania, USA
| | - Lingxia Chen
- Department of Microbiology and Immunology, Sol Sherry Thrombosis Research Center, Temple University , Philadelphia, Pennsylvania, USA
| | - Weidong Xiao
- Department of Microbiology and Immunology, Sol Sherry Thrombosis Research Center, Temple University , Philadelphia, Pennsylvania, USA
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Dey S, Laredj L, Damjanovic K, Muller M, Beard P. Growth of osteosarcoma cells in a three-dimensional bone-like matrix alters their susceptibility to adeno-associated virus. J Gen Virol 2014; 95:1539-1543. [PMID: 24728713 DOI: 10.1099/vir.0.061945-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Osteosarcoma cells U2OS are partially susceptible to adeno-associated virus (AAV)-2 infection, allowing efficient synthesis of Rep proteins and, in a low percentage of cells, capsid production. It is not clear if this partial susceptibility to infection is due to the bone-cell-like nature of these cells or is a result of their transformed properties. Here, we grew osteosarcoma cells in a biomimetic three-dimensional bone-like matrix composed of calcium phosphate and chitosan, and tested whether this would increase or reduce their permissiveness to virus. The osteosarcoma cells grew in the matrix and began to express the alkaline phosphatase bone cell differentiation marker. This was accompanied by a block to their infection by AAV, as indicated by Rep and capsid production. Infection of cells growing in three-dimensional tissue-like matrices could be, in a wider context, a practical way to mimic in vivo conditions.
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Affiliation(s)
- Sangeeta Dey
- Swiss Federal Institute of Technology Lausanne (EPFL), Faculty of Life Sciences, EPFL SV-DEC PH-SV, SV 3516 - Station 19, 1015 Lausanne, Switzerland
| | - Leila Laredj
- Swiss Federal Institute of Technology Lausanne (EPFL), Faculty of Life Sciences, EPFL SV-DEC PH-SV, SV 3516 - Station 19, 1015 Lausanne, Switzerland
| | - Katarina Damjanovic
- Swiss Federal Institute of Technology Lausanne (EPFL), Faculty of Life Sciences, EPFL SV-DEC PH-SV, SV 3516 - Station 19, 1015 Lausanne, Switzerland
| | - Manon Muller
- Swiss Federal Institute of Technology Lausanne (EPFL), Faculty of Life Sciences, EPFL SV-DEC PH-SV, SV 3516 - Station 19, 1015 Lausanne, Switzerland
| | - Peter Beard
- Swiss Federal Institute of Technology Lausanne (EPFL), Faculty of Life Sciences, EPFL SV-DEC PH-SV, SV 3516 - Station 19, 1015 Lausanne, Switzerland
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20
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Martin J, Frederick A, Luo Y, Jackson R, Joubert M, Sol B, Poulin F, Pastor E, Armentano D, Wadsworth S, Vincent K. Generation and characterization of adeno-associated virus producer cell lines for research and preclinical vector production. Hum Gene Ther Methods 2013; 24:253-69. [PMID: 23848282 DOI: 10.1089/hgtb.2013.046] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adeno-associated virus (AAV) producer cell lines represent an effective method for large-scale production of AAV vectors. We set out to evaluate and characterize the use of an abbreviated protocol to generate "masterwells" (MWs; a nonclonal cell population) as a platform for research and preclinical vector production. In this system, a single plasmid containing three components, the vector sequence, the AAV rep, and cap genes, and a selectable marker gene is stably transfected into HeLaS3 cells. Producer cell lines generating an AAV2 vector expressing a secreted form of human placental alkaline phosphatase (SEAP) have been created. Several MWs showed vector yields in the 5×10(4) to 2×10(5) DNase-resistant particles/cell range, and the productivity was stable over >60 population doublings. Integrated plasmid copy number in three high-producing MWs ranged from approximately 12 to 50; copies were arranged in a head-to-tail configuration. Upon infection with adenovirus, rep/cap copy number was amplified approximately 100-fold and high yield appeared to be dependent on the extent of amplification. Rep/cap gene expression and vector packaging both reached a peak at 48 hr postinfection. AAV2-SEAP vector was produced in 1-liter shaker culture and purified for assessment of vector quality and potency. The data showed that the majority of the capsids from the MWs contained vector DNA (≥70%) and that purified vector was free of replication-competent AAV. In vitro and in vivo analyses demonstrated that potency of the producer cell-derived vector was comparable to vector generated via the standard transfection method.
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Affiliation(s)
- John Martin
- Genzyme, a Sanofi company , Framingham, MA 01701-9322, USA
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Louis Jeune V, Joergensen JA, Hajjar RJ, Weber T. Pre-existing anti-adeno-associated virus antibodies as a challenge in AAV gene therapy. Hum Gene Ther Methods 2013; 24:59-67. [PMID: 23442094 DOI: 10.1089/hgtb.2012.243] [Citation(s) in RCA: 225] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Adeno-associated virus (AAV)-based vectors are promising tools for gene therapeutic applications, in part because AAVs are nonpathogenic viruses, and vectors derived from them can drive long-term transgene expression without integration of the vector DNA into the host genome. AAVs are not strongly immunogenic, but they can, nonetheless, give rise to both a cellular and humoral immune response. As a result, a significant fraction of potential patients for AAV-based gene therapy harbors pre-existing antibodies against AAV. Because even very low levels of antibodies can prevent successful transduction, antecedent anti-AAV antibodies pose a serious obstacle to the universal application of AAV gene therapy. In this review, we discuss the current knowledge of the role of anti-AAV antibodies in AAV-based gene therapy with a particular emphasis on approaches to overcome the hurdle that they pose.
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Affiliation(s)
- Vedell Louis Jeune
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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22
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Abstract
Adeno-associated virus (AAV) has emerged as an attractive vector for gene therapy. The benefits of using AAV for gene therapy include long-term gene expression, the inability to autonomously replicate without a helper virus, transduction of dividing and nondividing cells, and the lack of pathogenicity from wild-type infections. A number of Phase I and Phase II clinical trials utilizing AAV have been carried out worldwide (Aucoin et al., 2008; Mueller and Flotte, 2008). A number of challenges have been identified based upon data generated from these clinical trials. These challenges include (1) large scale manufacturing technologies in accordance with current Good Manufacturing Practices (cGMP), (2) tissue specific tropism of AAV vectors, (3) high-quality/high potency recombinant AAV vectors (rAAV), and (4) immune response to AAV capsids and transgene. In this chapter, we will provide an overview of AAV biology, AAV vectorology, rAAV manufacturing, and the current status on the latest rAAV clinical trials.
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23
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Glauser DL, Fraefel C. Interactions between AAV-2 and HSV-1: implications for hybrid vector design. Future Virol 2011. [DOI: 10.2217/fvl.11.13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herpes simplex virus type 1 (HSV-1)-based amplicon vectors have a transgene capacity of up to 150 kbp and can efficiently transduce many different cell types in culture and in vivo without causing cytopathic effects. However, these vectors do not support long-term transgene expression. Adeno-associated virus type 2 (AAV-2) has the capacity to integrate its genome into a specific site on human chromosome 19, but AAV-2-derived gene therapy vectors have a transgene capacity of only 4.5 kb. To combine the large transgene capacity of HSV-1 with the potential for site-specific genomic integration and long-term transgene expression of AAV-2, HSV/AAV hybrid vectors have been developed. This review describes the design, applications and limitations of these hybrid vectors. However, as HSV-1 is a full helper virus for AAV-2 replication, the main focus is the analysis of the molecular mechanisms of interaction between the two viruses. The knowledge of these interactions will have direct implications on the design of novel HSV/AAV hybrid vectors.
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Affiliation(s)
- Daniel L Glauser
- Division of Virology, Department of Pathology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QP, UK
| | - Cornel Fraefel
- Institute of Virology, University of Zurich, Winterthurerstr. 266a, 8057 Zurich, Switzerland
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24
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Abstract
Adeno-associated virus (AAV) vectors have evolved over the past decade as a particularly useful gene -vector for in vivo applications. In contrast to oncoretro- and lentiviral vectors, this vector stays essentially episomal after gene transfer, making it safer because of the absence of insertional mutagenesis. AAV's non-pathogenicity is a further advantage. For decades, this vector could only be produced at a small scale for research purposes and, eventually, used at very small doses for clinical studies, because only transfection methods were available, which have limited scalability. However, since the development of scalable production methods, this bottleneck is resolved and, from a technical point of view, large quantities of AAV vectors can be produced, opening the possibility of using AAV vectors for whole body treatments in gene therapy trials. This chapter presents the basic principles of small- and large-scale production procedures as well as detailed procedure of small-scale production, purification, and analytical protocols for AAV vectors. In Chapter 10, the reader will find a large-scale production method based on the use of the insect cell/baculovirus system.
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Mitchell AM, Nicolson SC, Warischalk JK, Samulski RJ. AAV's anatomy: roadmap for optimizing vectors for translational success. Curr Gene Ther 2010; 10:319-340. [PMID: 20712583 PMCID: PMC3920455 DOI: 10.2174/156652310793180706] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 07/20/2010] [Indexed: 12/14/2022]
Abstract
Adeno-Associated Virus based vectors (rAAV) are advantageous for human gene therapy due to low inflammatory responses, lack of toxicity, natural persistence, and ability to transencapsidate the genome allowing large variations in vector biology and tropism. Over sixty clinical trials have been conducted using rAAV serotype 2 for gene delivery with a number demonstrating success in immunoprivileged sites, including the retina and the CNS. Furthermore, an increasing number of trials have been initiated utilizing other serotypes of AAV to exploit vector tropism, trafficking, and expression efficiency. While these trials have demonstrated success in safety with emerging success in clinical outcomes, one benefit has been identification of issues associated with vector administration in humans (e.g. the role of pre-existing antibody responses, loss of transgene expression in non-immunoprivileged sites, and low transgene expression levels). For these reasons, several strategies are being used to optimize rAAV vectors, ranging from addition of exogenous agents for immune evasion to optimization of the transgene cassette for enhanced therapeutic output. By far, the vast majority of approaches have focused on genetic manipulation of the viral capsid. These methods include rational mutagenesis, engineering of targeting peptides, generation of chimeric particles, library and directed evolution approaches, as well as immune evasion modifications. Overall, these modifications have created a new repertoire of AAV vectors with improved targeting, transgene expression, and immune evasion. Continued work in these areas should synergize strategies to improve capsids and transgene cassettes that will eventually lead to optimized vectors ideally suited for translational success.
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Affiliation(s)
- Angela M. Mitchell
- UNC Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Sarah C. Nicolson
- UNC Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Jayme K. Warischalk
- UNC Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - R. Jude Samulski
- UNC Gene Therapy Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
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Bandyopadhyay S, Cao M, Liu Y, Hermonat PL. HPV E1 up-regulates replication-related biochemistries of AAV Rep78. Virology 2010; 402:94-101. [PMID: 20378143 DOI: 10.1016/j.virol.2010.03.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Revised: 02/09/2010] [Accepted: 03/01/2010] [Indexed: 11/26/2022]
Abstract
Human papillomavirus type 16 (HPV) E1 protein provides helper function for the adeno-associated virus type 2 (AAV) life cycle. E1 is the replication protein of HPV, analogous to AAV Rep78, but without the endonuclease/covalent attachment activity of Rep78. Previously we have shown that E1 and Rep78 interact in vitro. Here we investigated E1's effects on Rep78 interaction with AAV's inverted terminal repeat (ITR) DNA in vitro, using purified Rep78 and E1 proteins from bacteria. E1 enhanced Rep78-ITR binding, ATPase activity, Rep78-ITR-covalent linkage and Rep78-ITR-endonuclease activity (central to AAV replication). These enhancements occurred in a dose-dependent manner whenever assayed. However, overall Rep78-plus-E1 helicase activity was lower than Rep78's helicase activity. These data suggest that E1's broad-based helper function for the AAV life cycle (AAV DNA, mRNA, and protein levels are up-regulated by E1) is likely through its ability to enhance Rep78's critical replication-required biochemistries on ITR DNA.
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Affiliation(s)
- Sarmistha Bandyopadhyay
- Department of Internal Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, AR 72205, USA
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Zhang H, Xie J, Xie Q, Wilson JM, Gao G. Adenovirus–Adeno-Associated Virus Hybrid for Large-Scale Recombinant Adeno-Associated Virus Production. Hum Gene Ther 2009; 20:922-9. [DOI: 10.1089/hum.2009.125] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Hongwei Zhang
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605
| | - Jun Xie
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605
| | - Qing Xie
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605
- Department of Microbiology, Peking University Health Science Center, Beijing 100191, China
| | - James M. Wilson
- Gene Therapy Program, University of Pennsylvania School of Medicine, Philadelphia, PA 19104
| | - Guangping Gao
- Gene Therapy Center, University of Massachusetts Medical School, Worcester, MA 01605
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Adeno-associated virus type 2 induces apoptosis in human papillomavirus-infected cell lines but not in normal keratinocytes. J Virol 2009; 83:10286-92. [PMID: 19625406 DOI: 10.1128/jvi.00343-09] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The results of seroepidemiological studies suggest that infection with adeno-associated virus type 2 (AAV2) is negatively correlated with the incidence of human papillomavirus (HPV)-associated cervical cancer. We studied the potential of AAV2 oncosuppression of HPV and showed that HPV/AAV2 coinfection of cells culminated in apoptotic death, as determined by DNA laddering and caspase-3 cleavage. The induction of apoptosis coincided with AAV2 Rep protein expression; increased S-phase progression; upregulated pRb displaying both hyper- and hypophosphorylated forms; increased levels of p21(WAF1), p16(INK4), and p27(KIP1) proteins; and diminished levels of E7 oncoprotein. In contrast, normal keratinocytes that were infected with AAV2 or transfected with the cloned full-length AAV2 genome failed to express Rep proteins or undergo apoptosis. The failure of AAV2 to productively infect normal keratinocytes could be clinically advantageous. The delineation of the molecular mechanisms underlying the HPV/AAV2 interaction could be harnessed for developing novel AAV2-derived therapeutics for cervical cancer.
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29
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Kang BY, You H, Bandyopadhyay S, Agrawal N, Melchert RB, Basnakian AG, Liu Y, Hermonat PL. Cervical cancer isolate PT3, super-permissive for adeno-associated virus replication, over-expresses DNA polymerase delta, PCNA, RFC and RPA. BMC Microbiol 2009; 9:79. [PMID: 19389243 PMCID: PMC2685399 DOI: 10.1186/1471-2180-9-79] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Accepted: 04/23/2009] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Adeno-associated virus (AAV) type 2 is an important virus due to its use as a safe and effective human gene therapy vector and its negative association with certain malignancies. AAV, a dependo-parvovirus, autonomously replicates in stratified squamous epithelium. Such tissue occurs in the nasopharynx and anogenitals, from which AAV has been clinically isolated. Related autonomous parvoviruses also demonstrate cell tropism and preferentially replicate in oncogenically transformed cells. Combining these two attributes of parvovirus tropism, squamous and malignant, we assayed if AAV might replicate in squamous cervical carcinoma cell isolates. RESULTS Three primary isolates (PT1-3) and two established cervical cancer cell lines were compared to normal keratinocytes (NK) for their ability to replicate AAV. One isolate, PT3, allowed for high levels of AAV DNA replication and virion production compared to others. In research by others, four cellular components are known required for in vitro AAV DNA replication: replication protein A (RPA), replication factor C (RFC), proliferating cell nuclear antigen (PCNA), and DNA polymerase delta (POLD1). Thus, we examined PT3 cells for expression of these components by DNA microarray and real-time quantitative PCR. All four components were over-expressed in PT3 over two representative low-permissive cell isolates (NK and PT1). However, this super-permissiveness did not result in PT3 cell death by AAV infection. CONCLUSION These data, for the first time, provide evidence that these four cellular components are likely important for AAV in vivo DNA replication as well as in vitro. These data also suggest that PT3 will be a useful reagent for investigating the AAV-permissive transcriptome and AAV anti-cancer effect.
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Affiliation(s)
- Bum Yong Kang
- Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Central Arkansas Veterans Healthcare System, John L McClellan Memorial Veterans Hospital, 4300 West 7th St., Little Rock, AR 72205, USA
| | - Hong You
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
| | - Sarmistha Bandyopadhyay
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
| | - Nalini Agrawal
- Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
| | - Russell B Melchert
- Pharmaceutical Sciences, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
| | - Alexei G Basnakian
- Pharmacology and Toxicology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Central Arkansas Veterans Healthcare System, John L McClellan Memorial Veterans Hospital, 4300 West 7th St., Little Rock, AR 72205, USA
| | - Yong Liu
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
| | - Paul L Hermonat
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Obstetrics and Gynecology, University of Arkansas for Medical Sciences, 4301 West Markham St, Little Rock, AR 72205, USA
- Central Arkansas Veterans Healthcare System, John L McClellan Memorial Veterans Hospital, 4300 West 7th St., Little Rock, AR 72205, USA
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Bandyopadhyay S, Raney KD, Liu Y, Hermonat PL. AAV-2 Rep78 and HPV-16 E1 interact in vitro, modulating their ATPase activity. Biochemistry 2007; 47:845-56. [PMID: 18092809 DOI: 10.1021/bi701579v] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Adeno-associated virus (AAV) is a nonpathogenic single-stranded human parvovirus which usually requires the presence of a "helper" virus for strong DNA replication. In addition to adeno- and herpes viruses, human papillomavirus (HPV) can serve as an AAV helper. We recently published that HPV type 16 (HPV-16) E1 protein contributes significantly as an individual helper gene for AAV-2 DNA replication and transcription. As Rep78 and E1 are the corresponding DNA helicase/replication proteins of AAV and HPV, respectively, and Rep78 and E1 have a degree of homology, we assayed whether these two proteins interact physically. The full length proteins were purified from bacteria as GST-E1 and MBP-Rep78 and used in five assays to observe Rep78-E1 interactions. All five assays (pull-down, coimmunoprecipitation, enzyme-linked immunosorbent assay (ELISA), chemical cross-linking, and ATPase activity) provided evidence consistent with Rep78-E1 interaction. Most intriguing, an overall decrease in ATPase activity was observed when both proteins were present together. These data strongly suggest that E1 and Rep78 interact and that this interaction modulates at least some of their individual biochemical functions. This study adds to our understanding of AAV-HPV interaction biology, E1's modulation of Rep78 biochemistry, Rep78's modulation of E1 biochemistry and provides initial clues which may lead to the underlying mechanism of HPV E1 helper function for AAV DNA replication.
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Affiliation(s)
- Sarmistha Bandyopadhyay
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham Street, Little Rock, Arkansas 72205, USA
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Adeno-associated virus type 12 (AAV12): a novel AAV serotype with sialic acid- and heparan sulfate proteoglycan-independent transduction activity. J Virol 2007; 82:1399-406. [PMID: 18045941 DOI: 10.1128/jvi.02012-07] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV) is a promising vector for gene therapy. Recent isolations of novel AAV serotypes have led to significant advances by broadening the tropism and increasing the efficiency of gene transfer to the desired target cell. However, a major concern that remains is the strong preexisting immune responses to several vectors. In this paper, we describe the isolation and characterization of AAV12, an AAV serotype with unique biological and immunological properties. In contrast to those of all other reported AAVs, AAV12 cell attachment and transduction do not require cell surface sialic acids or heparan sulfate proteoglycans. Furthermore, rAAV12 is resistant to neutralization by circulating antibodies from human serum. The feasibility of rAAV12 as a vector was demonstrated in a mouse model in which muscle and salivary glands were transduced. These characteristics make rAAV12 an interesting candidate for gene transfer applications.
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Garner E, Martinon F, Tschopp J, Beard P, Raj K. Cells with defective p53-p21-pRb pathway are susceptible to apoptosis induced by p84N5 via caspase-6. Cancer Res 2007; 67:7631-7. [PMID: 17699767 DOI: 10.1158/0008-5472.can-07-0334] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Adeno-associated virus (AAV) infection triggers a DNA damage response in the cell. This response is not induced by viral proteins but by virtue of the structure of AAV ssDNA being recognized by the cell as damaged DNA. The consequence of this is the killing of cells lacking p53 activity. We have observed that cells that lack p21 or pRb activity are also sensitive to AAV-induced cell death. We report that cells respond to AAV infection by activating two DNA damage signaling cascades. The first activates the p84N5 protein, which in turn activates caspase-6, leading to cell death. The second cascade activates the p53-21-pRb pathway, which inhibits activation of the p84N5 protein and thus prevents cell death. The result of the antagonistic interaction between these two pathways is that cells that do not exhibit functional p53-p21-pRb signaling undergo apoptosis as a consequence of AAV infection. Cells with a functional p53-21-pRb pathway are refractory to AAV-induced cell death. These results show that p53, although a proapoptotic protein, together with pRb and p21 proteins, is a member of an antiapoptotic cellular mechanism. As such, these experiments reveal features that may be exploited to specifically kill cells that lack the p53-p21-pRb pathway, such as cancer cells. The use of AAV to expose these subtle characteristics of intracellular signaling further highlights the advantages of using viruses as precision tools with which to address questions of cell biology.
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Affiliation(s)
- Elizabeth Garner
- Department of Virology, National Institute for Medical Research, London, United Kingdom
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33
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Murray S, Nilsson CL, Hare JT, Emmett MR, Korostelev A, Ongley H, Marshall AG, Chapman MS. Characterization of the capsid protein glycosylation of adeno-associated virus type 2 by high-resolution mass spectrometry. J Virol 2006; 80:6171-6. [PMID: 16731956 PMCID: PMC1472596 DOI: 10.1128/jvi.02417-05] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Adeno-associated virus type 2 (AAV-2) capsid proteins have eight sequence motifs that are potential sites for O- or N-linked glycosylation. Three are in prominent surface locations, close to the sites of cellular receptor attachment and to neutralizing epitopes on or near protrusions surrounding the three-fold axes, raising the possibility that AAV-2 might use glycosylation as a means of immune escape or for preventing reattachment on release of progeny virus. Peptide mapping and structural analysis by Fourier transform ion cyclotron resonance mass spectrometry demonstrates, however, no glycosylation of the capsid protein for virus prepared in cultured HeLa cells.
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Affiliation(s)
- Sarah Murray
- Institute of Molecular Biophysics, Florida State University, Tallahassee, FL 32306-4380, USA
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34
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Park JY, Lim BP, Lee K, Kim YG, Jo EC. Scalable production of adeno-associated virus type 2 vectors via suspension transfection. Biotechnol Bioeng 2006; 94:416-30. [PMID: 16622883 DOI: 10.1002/bit.20776] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Vectors derived from adeno-associated virus type 2 (AAV2) are promising gene delivery vehicles, but it is still challenging to get the large number of recombinant adeno-associated virus (rAAV) particles required for large animal and clinical studies. Current transfection technology requires adherent cultures of HEK 293 cells that can only be expanded by preparing multiple culture plates. A single large-scale suspension culture could replace these multiple culture preparations, but there is currently no effective co-transfection scheme for generating rAAV from cells in suspension culture. Here, we weaned HEK 293 cells to suspension culture using hydrogel-coated six-well culture plates and established an efficient transfection strategy suitable for these cells. Then the cultures were gradually scaled up. We used linear polyethylenimine (PEI) to mediate transfection and obtained high transfection efficiencies ranging from 54% to 99%, thereby allowing efficient generation of rAAV vectors. Up to 10(13) rAAV particles and, more importantly, up to 10(11) infectious particles were generated from a 2-L bioreactor culture. The suspension-transfection strategy of this study facilitates the homogeneous preparation of rAAV at a large scale, and holds further potential as the basis for establishing a manufacturing process in a larger bioreactor.
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Affiliation(s)
- Joon Young Park
- MOGAM Biotechnology Research Institute, 341 Pojung-Ri Koosung-Eup Yongin, Kyonggi-Do 449-913, Republic of Korea
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35
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You H, Liu Y, Prasad CK, Agrawal N, Zhang D, Bandyopadhyay S, Liu H, Kay HH, Mehta JL, Hermonat PL. Multiple human papillomavirus genes affect the adeno-associated virus life cycle. Virology 2005; 344:532-40. [PMID: 16203022 DOI: 10.1016/j.virol.2005.08.039] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2005] [Revised: 05/25/2005] [Accepted: 08/02/2005] [Indexed: 11/30/2022]
Abstract
The risk of cervical cancer, one of the most prevalent cancers in the world, is determined by two viruses. Human papillomavirus (HPV) is the main risk factor for developing cervical cancer. However, although little known, it is well substantiated that the human Parvovirus adeno-associated virus type 2 (AAV), and its encoded Rep78 protein, interacts with HPV and lowers the risk of cervical cancer. HPV also contributes to AAV inhibition by serving as a helper virus for AAV and stimulating higher AAV replication levels. Here we surveyed four HPV-16 early genes, E1, E2, E6 and E7, for their ability to increase/decrease the basal level of AAV replication in stratifying squamous epithelium (the epithelial raft culture system). It was found that the HPV-16 E1, E2 and E6 genes were able to help/enhance AAV-2 replication in epithelial raft cultures. Under these conditions, with all the HPV genes being expressed from the AAV p5 promoter, E1 appeared to have the strongest enhancing effect on AAV DNA replication (Southern blot), RNA expression (RT-PCR), protein expression (Western blot) and AAV virion production (2 plate-Southern blot). Further study of E1 mutants showed that the carboxy-half of E1, the putative helicase/ATPase domain, was the main contributor of helper activity. These data are important for understanding the HPV-AAV interaction and its effect on modifying cervical cancer risk. These data also suggest the possibility that the identified HPV helper genes may be useful in the generation of recombinant (r)AAV virions for gene therapy, as rAAV is increasing in popularity for such purposes.
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Affiliation(s)
- Hong You
- Department of Internal Medicine, Gene Therapy Program, University of Arkansas for Medical Sciences, 4301 West Markham St., Little Rock, AR 72205, USA
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36
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Adeno-associated virus type 2 enhances goose parvovirus replication in embryonated goose eggs. Virology 2005; 336:265-73. [DOI: 10.1016/j.virol.2005.03.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Revised: 02/03/2005] [Accepted: 03/21/2005] [Indexed: 11/24/2022]
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37
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Prasad CK, Meyers C, Zhan DJ, You H, Chiriva-Internati M, Mehta JL, Liu Y, Hermonat PL. The adeno-associated virus major regulatory protein Rep78-c-Jun-DNA motif complex modulates AP-1 activity. Virology 2003; 314:423-31. [PMID: 14517094 DOI: 10.1016/s0042-6822(03)00439-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Multiple epidemiologic studies show that adeno-associated virus (AAV) is negatively associated with cervical cancer (CX CA), a cancer which is positively associated with human papillomavirus (HPV) infection. Mechanisms for this correlation may be by Rep78's (AAV's major regulatory protein) ability to bind the HPV-16 p97 promoter DNA and inhibit transcription, to bind and interfere with the functions of the E7 oncoprotein of HPV-16, and to bind a variety of HPV-important cellular transcription factors such as Sp1 and TBP. c-Jun is another important cellular factor intimately linked to the HPV life cycle, as well as keratinocyte differentiation and skin development. Skin is the natural host tissue for both HPV and AAV. In this article it is demonstrated that Rep78 directly interacts with c-Jun, both in vitro and in vivo, as analyzed by Western blot, yeast two-hybrid cDNA, and electrophoretic mobility shift-supershift assay (EMSA supershift). Addition of anti-Rep78 antibodies inhibited the EMSA supershift. Investigating the biological implications of this interaction, Rep78 inhibited the c-Jun-dependent c-jun promoter in transient and stable chloramphenicol acetyl-transferase (CAT) assays. Rep78 also inhibited c-Jun-augmented c-jun promoter as well as the HPV-16 p97 promoter activity (also c-Jun regulated) in in vitro transcription assays in T47D nuclear extracts. Finally, the Rep78-c-Jun interaction mapped to the amino-half of Rep78. The ability of Rep78 to interact with c-Jun and down-regulate AP-1-dependent transcription suggests one more mechanism by which AAV may modulate the HPV life cycle and the carcinogenesis process.
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Affiliation(s)
- C Krishna Prasad
- Department of Internal Medicine, Gene Therapy Center for Molecular Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA
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Di Pasquale G, Chiorini JA. PKA/PrKX activity is a modulator of AAV/adenovirus interaction. EMBO J 2003; 22:1716-24. [PMID: 12660177 PMCID: PMC152897 DOI: 10.1093/emboj/cdg153] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2002] [Revised: 02/10/2003] [Accepted: 02/12/2003] [Indexed: 11/14/2022] Open
Abstract
Interference between viruses occurs when infection by one virus results in the inhibition of replication of another virus. Adeno-associated virus (AAV2) is a human parvovirus with the unique characteristics of a dependence upon a helper virus for a productive infection and the ability to interfere with the replication of the helper virus. Previously, we demonstrated that AAV2 Rep78 and Rep52 interact and inhibit cAMP-dependent protein kinase A (PKA) and its novel homolog PrKX. We hypothesized that modulation of PKA activity by AAV2 may be responsible for inhibition of helper virus replication. In this study we demonstrate that adenovirus replication is sensitive to PKA activity and that AAV2 Rep78/Rep52 proteins contain an inhibitory domain similar to that of the heat-stable PKA inhibitor. This domain, while not directly necessary for AAV2 replication and packaging, is necessary to preserve AAV2 replication fitness during an Ad co-infection. Furthermore, a mutant AAV2 virus lacking this region fails to inhibit adenovirus replication. Thus, inhibition of PKA activity by AAV2 constitutes a novel form of viral interference.
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Affiliation(s)
- Giovanni Di Pasquale
- Gene Therapy and Therapeutics Branch, NIDCR, NIH 10/1N113, 10 Center Drive MSC 1190, Bethesda, MD 20892-1190, USA
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39
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Agrawal N, Mane M, Chiriva-Internati M, Roman JJ, Hermonat PL. Temporal acceleration of the human papillomavirus life cycle by adeno-associated virus (AAV) type 2 superinfection in natural host tissue. Virology 2002; 297:203-10. [PMID: 12083819 DOI: 10.1006/viro.2002.1405] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Epidemiologically, certain human papillomaviruses are positively associated with cervical cancer, while adeno-associated viruses (AAV-2) are negatively associated with this same cancer. Both HPV and AAV productively replicate in differentiating keratinocytes of the skin and interact with each other. However, AAV has a relatively fast life cycle, generating infectious progeny by the third to fourth day of an organotypic epithelial raft culture. In contrast, HPV is slow, generating infectious progeny only after 10-12 days. As earlier studies indicated that these two skin-tropic virus types significantly affect each other's life cycle, we investigated if the temporal kinetics of the slow HPV life cycle was affected by the fast AAV in raft cultures. Here it is shown that the presence of AAV-2 at a variety of multiplicities of infection (m.o.i.) resulted in early onset HPV-31b DNA replication. Using plasmids which each expressed only one of the four rep proteins, an enhancement affect was seen for all four rep proteins of AAV, with Rep40 having the highest activity. Furthermore, AAV (m.o.i. of 5) also resulted in a temporally accelerated production of HPV infectious units, seen as early as Day 4, with high levels of viral progeny being produced by Day 6.5. Like earlier studies at Day 12, histological differences were seen at Day 6.5 between AAV-infected and mock-infected HPV/rafts. These data suggest that under specific conditions the AAV rep trans-factors can positively regulate HPV gene expression in addition to the usual negative regulation that has been consistently observed by the rep proteins. These data also suggest that AAV has a significant effect upon the temporal kinetics of the HPV life cycle in natural host tissue. However, it is unclear if or how this AAV-induced fast HPV life cycle mechanistically correlates with lower rates of HPV-associated cervical disease.
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Affiliation(s)
- Nalini Agrawal
- Department of Obstetrics and Gynecology, University of Arkansas for Medical Sciences, Little Rock, Arkansas 72205, USA
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40
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Kiehl K, Schlehofer JR, Schultz R, Zugaib M, Armbruster-Moraes E. Adeno-associated virus DNA in human gestational trophoblastic disease. Placenta 2002; 23:410-5. [PMID: 12061857 DOI: 10.1053/plac.2002.0827] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Previous studies had shown a correlation between infection with the human adeno-associated virus (AAV) and spontaneous abortion in early pregnancy. Furthermore, AAV DNA had been detected in cells of the human trophoblast lines, Jeg-3, JAr, and BeWo, in cells of the human amnion line, FL, and in trophoblasts from amnion fluids. Infectious AAV virions could be isolated from amnion fluids. To further analyse AAV infection during pregnancy, we tested material from Gestational Trophoblastic Disease for the presence of AAV DNA. With 63 tissue samples from patients from Brazil, including 49 hydatiform moles and 14 choriocarcinomas, nested PCR was performed to detect the presence of AAV DNA. In addition, 15 samples from spontaneous abortions were analysed. AAV DNA was found in 43 samples (28/49 hydatiform moles, 4/14 choriocarcinomas, 11/15 miscarriage material). These findings confirm AAV infection of embryo-derived tissue in humans and further suggest a role of AAV in miscarriage and trophoblastic disease.
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Affiliation(s)
- K Kiehl
- Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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41
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Gao GP, Lu F, Sanmiguel JC, Tran PT, Abbas Z, Lynd KS, Marsh J, Spinner NB, Wilson JM. Rep/Cap gene amplification and high-yield production of AAV in an A549 cell line expressing Rep/Cap. Mol Ther 2002; 5:644-9. [PMID: 11991756 DOI: 10.1006/mthe.2001.0591] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Cell lines stably expressing rep/cap are important tools for studying adeno-associated virus (AAV) biology and producing AAV vectors. Several rep/cap cell lines have been isolated, each of which is based on HeLa cells. Infection of these cell lines with adenovirus for production of AAV vector is associated with substantial amplification of the rep/cap gene. Concerns over the presence of human papilloma viral (HPV) sequences in HeLa cells may limit use of such lines for production of clinical-grade vectors. Here we describe a non-HeLa-derived rep/cap cell line called K209, generated by stable transfection of A549 cells with a plasmid construct containing the P5 rep/cap cassette from AAV2. Infection of K209 cells with adenovirus leads to a 1000-fold amplification of the rep/cap gene with high-yield production of AAV vectors. The multiplicity of infection (MOI) of adenovirus that led to maximum amplification of the rep/cap gene and high-level production of AAV is 10 times higher in the HeLa-based cell line than that required in K209 cells. Our data suggest that papilloma-derived gene products present in HeLa cells are not required for high-yield production of AAV vectors.
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Affiliation(s)
- Guang-ping Gao
- Institute for Human Gene Therapy, Department of Molecular, the Wistar Institute, Philadelphia, Pennsylvania, 19104-4268, USA
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Nada S, Trempe JP. Characterization of adeno-associated virus rep protein inhibition of adenovirus E2a gene expression. Virology 2002; 293:345-55. [PMID: 11886255 DOI: 10.1006/viro.2001.1286] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Adeno-associated virus (AAV) replication (Rep) proteins are pleiotropic effectors of viral DNA replication, RNA transcription, and site-specific integration into chromosome 19. In addition to regulating AAV gene expression, the Rep proteins modulate expression of a variety of cellular and viral genes. In this report we investigate Rep-mediated effects on expression of the adenovirus (Ad) E2a gene and the Ad major late promoter. We have found that all four Rep proteins repress E2a expression at the protein level, with Rep40 showing the weakest repression. Mutations in the purine nucleotide binding (PNB) site weakened each of the protein's abilities to repress expression. Analysis of steady-state E2a mRNA showed that Rep proteins decreased mRNA levels, but to a lesser extent than E2a protein levels. Analysis of mRNA stability demonstrated that neither Rep78 nor Rep52 affected E2a mRNA stability, suggesting that the decrease in mRNA is due to Rep-mediated inhibition of Ad E2a transcription. To determine if Rep68 proteins could directly inhibit RNA transcription, we performed in vitro transcription assays using HeLa nuclear extracts supplemented with Rep68 and Rep68PNB. We demonstrate that Rep68, but not mutant Rep68PNB, blocked in vitro transcription of a template containing the Ad major late promoter. These results provide insight into how AAV and its encoded Rep proteins interact with Ad and provide a model system for the study of AAV and host-cell interactions.
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Affiliation(s)
- Shadia Nada
- Department of Biochemistry and Molecular Biology, Medical College of Ohio, 3035 Arlington Avenue, Toledo, Ohio 43614-5804, USA
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43
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Jing XJ, Kalman-Maltese V, Cao X, Yang Q, Trempe JP. Inhibition of adenovirus cytotoxicity, replication, and E2a gene expression by adeno-associated virus. Virology 2001; 291:140-51. [PMID: 11878883 DOI: 10.1006/viro.2001.1192] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adeno-associated virus (AAV) and the other parvoviruses have long been known to inhibit proliferation of nonpermissive cells. The mechanism of this inhibition is not thoroughly understood. To learn how AAV interacts with host cells, we have begun an investigation into AAV's relationship with adenovirus (Ad), AAV's most efficient helper virus. AAV, but not UV-inactivated AAV, delayed Ad-induced cytotoxicity and inhibited Ad E2a gene expression. AAV, but not UV-inactivated AAV or a recombinant AAV vector, inhibited Ad DNA replication. To determine whether AAV or its replication (Rep) proteins alter Ad early gene expression, we measured steady state E2a mRNA levels in AAV and Ad coinfected cultures and in a cell line (Neo6) that inducibly expresses the Rep proteins. AAV, but not UV-AAV, and Rep expression resulted in diminution of E2a protein and mRNA levels. To determine whether the AAV Rep proteins directly affect the individual Ad early promoters, we constructed luciferase reporter plasmids containing each of the five early promoters. Cotransfection of Ad-luciferase and an AAV rep gene-expressing plasmid in HeLa cells demonstrated that Rep78 repressed the E1a, E2a, and E4 promoters but trans-activated the E1b and E3 promoters. In the presence of a cotransfected E1a-expressing plasmid, Rep78 repressed expression from all five promoters. These results indicate that Rep may have different effects on the Ad early promoters dependent upon the presence of the E1a trans-activating protein.
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Affiliation(s)
- X J Jing
- Department of Biochemistry and Molecular Biology, Medical College of Ohio, 3035 Arlington Avenue, Toledo, Ohio 43614-5804, USA
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Erles K, Rohde V, Thaele M, Roth S, Edler L, Schlehofer JR. DNA of adeno-associated virus (AAV) in testicular tissue and in abnormal semen samples. Hum Reprod 2001; 16:2333-7. [PMID: 11679515 DOI: 10.1093/humrep/16.11.2333] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Human genital tissues, including spermatozoa, have been found to be frequently infected with the helper-virus dependent parvovirus, adeno-associated virus (AAV). METHODS To assess the role of AAV infection in disorders of the male reproductive system, semen samples from 95 men (including 73 men attending a fertility programme) and testicular samples from patients with azoospermia (n = 38) or prostate cancer (n = 8) were analysed using polymerase chain reaction for the presence of AAV DNA. Semen quality was assessed according to World Health Organization guidelines and the grade of atrophy of testicular biopsies was determined histomorphologically. RESULTS AAV DNA was detected in 38% (28/73) of ejaculates from men with abnormal semen analyses (oligoasthenozoospermia or asthenozoospermia) and in 4.6% of normal semen samples (1/22, P = 0.003). DNA from AAV helper-viruses (human papillomaviruses, cytomegalovirus) was detected at similar frequencies in normal and abnormal semen samples. In testes, AAV DNA was detected in 10 out of 38 biopsies from infertile men (26%), and in 2 out of 8 orchidectomy samples. CONCLUSION The data show an increased incidence of AAV infection with abnormal semen analysis. Detection of AAV DNA in the testes might point to a role for AAV infection in male infertility, possibly by interfering with spermatozoa development.
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Affiliation(s)
- K Erles
- Angewandte Tumorvirologie, Deutsches Krebsforschungszentrum, Heidelberg, Germany
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45
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Abstract
A major goal of molecular oncology is to identify means to kill cells lacking p53 function. Most current cancer therapy is based on damaging cellular DNA by irradiation or chemicals. Recent reports support the notion that, in the event of DNA damage, the p53 tumour-suppressor protein is able to prevent cell death by sustaining an arrest of the cell cycle at the G2 phase. We report here that adeno-associated virus (AAV) selectively induces apoptosis in cells that lack active p53. Cells with intact p53 activity are not killed but undergo arrest in the G2 phase of the cell cycle. This arrest is characterized by an increase in p53 activity and p21 levels and by the targeted destruction of CDC25C. Neither cell killing nor arrest depends upon AAV-encoded proteins. Rather, AAV DNA, which is single-stranded with hairpin structures at both ends, elicits in cells a DNA damage response that, in the absence of active p53, leads to cell death. AAV inhibits tumour growth in mice. Thus viruses can be used to deliver DNA of unusual structure into cells to trigger a DNA damage response without damaging cellular DNA and to selectively eliminate those cells lacking p53 activity.
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Affiliation(s)
- K Raj
- Swiss Institute for Experimental Cancer Research (ISREC), Epalinges, Switzerland
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46
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Meyers C, Alam S, Mane M, Hermonat PL. Altered biology of adeno-associated virus type 2 and human papillomavirus during dual infection of natural host tissue. Virology 2001; 287:30-9. [PMID: 11504539 DOI: 10.1006/viro.2001.0968] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Adeno-associated virus (AAV), a common genital virus, may have a "protective" role against human papillomavirus (HPV)-associated cervical cancer. Epidemiological studies indicate a negative correlation between AAV infection and the incidence of cervical cancer. In contrast, HPV is positively associated with cervical cancer. To investigate interactions between these two viruses we used the organotypic "raft" culture system. The raft culture system is capable of supporting the complete HPV life cycle. Raft tissues that were actively replicating HPV were superinfected with AAV type 2 (AAV-2). We observed a multiplicity of infection (m.o.i.)-dependent enhancement and inhibition of HPV DNA replication, concomitant with AAV-2 replication. The data suggest that at low m.o.i. of AAV-2 infection, HPV DNA replication was slightly increased compared to controls and AAV-2 replicated poorly. At high AAV-2 m.o.i., HPV DNA replication was reduced and AAV-2 replicated to high levels. AAV-2 replication was increased in the presence of HPV compared to primary human keratinocyte, squamous cell carcinoma, and HaCat raft cultures infected with AAV-2 alone. These data suggest that HPV may provide types of "enhancer/helper" functions for AAV-2 replication and progeny formation. Infection with AAV-2 had significant effects on epithelial morphology. During infection with low m.o.i. of AAV-2 the epithelium stratified to a greater extent than in controls. With high m.o.i. of AAV-2 infections, tissue cytopathic effects were observed, indicating an additional factor responsible for the effect of AAV-2 on HPV replication and infection. Our results demonstrate a complex interaction between AAV-2, HPV, and skin during dual infection.
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Affiliation(s)
- C Meyers
- Department of Microbiology and Immunology, The Pennsylvania State University College of Medicine, Hershey, Pennsylvania 17033, USA
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Tessier J, Chadeuf G, Nony P, Avet-Loiseau H, Moullier P, Salvetti A. Characterization of adenovirus-induced inverted terminal repeat-independent amplification of integrated adeno-associated virus rep-cap sequences. J Virol 2001; 75:375-83. [PMID: 11119606 PMCID: PMC113930 DOI: 10.1128/jvi.75.1.375-383.2001] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Stable packaging cell lines expressing the rep and cap genes for recombinant adeno-associated virus type 2 (rAAV-2) assembly constitute an attractive alternative to transient transfection protocols. We recently characterized a stable HeLa rep-cap cell clone (HeRC32) and demonstrated that upon vector transfection and adenovirus infection, efficient rAAV assembly correlated with a 100-fold amplification of the integrated rep-cap sequence with the inverted terminal repeats (ITRs) deleted. We now report a more detailed analysis of this phenomenon and highlight the key cellular and viral factors involved. Determination of the rep-cap copy number of HeRC32 cells indicated that maximum rep-cap amplification occurred between 24 and 48 h following adenovirus infection. Analysis by pulsed-field gel electrophoresis of adenovirus-infected HeRC32 cells indicated that amplified rep-cap sequences were found in an extrachromosomal form. Amplification of the rep-cap sequence with the ITRs deleted was not dependent on adenovirus replication and still occurred when the highly specific adenovirus polymerase was inactivated. In contrast, amplification was inhibited in the presence of aphidicolin, indicating that cellular polymerases were needed. Our study also documented that among the adenovirus gene products, the DNA-binding protein (DBP) was essential, since rep-cap amplification was severely abrogated when HeRC32 cells were infected at a nonpermissive temperature with an adenovirus mutant encoding a thermosensitive DBP. Furthermore, expression of DBP alone in HeRC32 cells was sufficient to induce a sustained level of rep-cap amplification. Finally, immunofluorescence analysis showed that HeRC32 cells expressing the DBP also simultaneously expressed the Rep proteins, suggesting a possible involvement of the latter in rep-cap amplification. Indeed, the lack of detectable amplification in an adenovirus-infected stable rep-cap HeLa cell clone unable to produce Rep proteins further supported that, among the viral gene products, both the DBP and Rep proteins are necessary to induce the targeted amplification of the integrated rep-cap sequences in the absence of the AAV ITRs.
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Affiliation(s)
- J Tessier
- Laboratoire de Thérapie Génique, CHU Hôtel-Dieu, 44035 Nantes Cedex 01, France
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48
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Marcello A, Massimi P, Banks L, Giacca M. Adeno-associated virus type 2 rep protein inhibits human papillomavirus type 16 E2 recruitment of the transcriptional coactivator p300. J Virol 2000; 74:9090-8. [PMID: 10982355 PMCID: PMC102107 DOI: 10.1128/jvi.74.19.9090-9098.2000] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infection by human adeno-associated virus type 2 (AAV2) is a possible protective factor in the development of cervical carcinomas associated with human papillomaviruses (HPV). The replicative proteins of AAV2 (Rep) have been implicated in the inhibition of papillomavirus replication and transforming activities, although the molecular events underlying these effects are poorly understood. We observed that each of the four forms of AAV2 Rep inhibited the E1- and E2-driven replication of oncogenic HPV type 16 (HPV16). Rep40, corresponding to the C-terminal domain of all Rep proteins, inhibited both HPV DNA replication and HPV16 E2-mediated transactivation. Rep40 specifically bound the N-terminal transactivation domain of HPV16 E2 both in vitro and in vivo. This interaction was found to specifically disrupt the binding of E2 to the cellular transcriptional coactivator p300. Accordingly, the inhibitory effect of Rep on HPV16 E2 transactivation was rescued by the overexpression of p300. These data indicate a novel role of Rep in the down-regulation of papillomaviruses through inhibition of complex formation between the HPV16 E2 transcriptional activator and its cellular coactivator, p300.
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Affiliation(s)
- A Marcello
- Molecular Medicine, International Center for Genetic Engineering and Biotechnology, 34012 Trieste, Italy
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