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Pupo A, Fernández A, Low SH, François A, Suárez-Amarán L, Samulski RJ. AAV vectors: The Rubik's cube of human gene therapy. Mol Ther 2022; 30:3515-3541. [PMID: 36203359 PMCID: PMC9734031 DOI: 10.1016/j.ymthe.2022.09.015] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 12/12/2022] Open
Abstract
Defective genes account for ∼80% of the total of more than 7,000 diseases known to date. Gene therapy brings the promise of a one-time treatment option that will fix the errors in patient genetic coding. Recombinant viruses are highly efficient vehicles for in vivo gene delivery. Adeno-associated virus (AAV) vectors offer unique advantages, such as tissue tropism, specificity in transduction, eliciting of a relatively low immune responses, no incorporation into the host chromosome, and long-lasting delivered gene expression, making them the most popular viral gene delivery system in clinical trials, with three AAV-based gene therapy drugs already approved by the US Food and Drug Administration (FDA) or European Medicines Agency (EMA). Despite the success of AAV vectors, their usage in particular scenarios is still limited due to remaining challenges, such as poor transduction efficiency in certain tissues, low organ specificity, pre-existing humoral immunity to AAV capsids, and vector dose-dependent toxicity in patients. In the present review, we address the different approaches to improve AAV vectors for gene therapy with a focus on AAV capsid selection and engineering, strategies to overcome anti-AAV immune response, and vector genome design, ending with a glimpse at vector production methods and the current state of recombinant AAV (rAAV) at the clinical level.
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Affiliation(s)
- Amaury Pupo
- R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, Durham, NC 27709, USA
| | - Audry Fernández
- R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, Durham, NC 27709, USA
| | - Siew Hui Low
- R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, Durham, NC 27709, USA
| | - Achille François
- Viralgen. Parque Tecnológico de Guipuzkoa, Edificio Kuatro, Paseo Mikeletegui, 83, 20009 San Sebastián, Spain
| | - Lester Suárez-Amarán
- R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, Durham, NC 27709, USA
| | - Richard Jude Samulski
- R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, Durham, NC 27709, USA,Department of Pharmacology, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA,Corresponding author: Richard Jude Samulski, R&D Department, Asklepios BioPharmaceutical, Inc. (AskBio), 20 T.W. Alexander, Suite 110 RTP, NC 27709, USA.
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Hacker UT, Bentler M, Kaniowska D, Morgan M, Büning H. Towards Clinical Implementation of Adeno-Associated Virus (AAV) Vectors for Cancer Gene Therapy: Current Status and Future Perspectives. Cancers (Basel) 2020; 12:E1889. [PMID: 32674264 PMCID: PMC7409174 DOI: 10.3390/cancers12071889] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 07/03/2020] [Accepted: 07/07/2020] [Indexed: 02/06/2023] Open
Abstract
Adeno-associated virus (AAV) vectors have gained tremendous attention as in vivo delivery systems in gene therapy for inherited monogenetic diseases. First market approvals, excellent safety data, availability of large-scale production protocols, and the possibility to tailor the vector towards optimized and cell-type specific gene transfer offers to move from (ultra) rare to common diseases. Cancer, a major health burden for which novel therapeutic options are urgently needed, represents such a target. We here provide an up-to-date overview of the strategies which are currently developed for the use of AAV vectors in cancer gene therapy and discuss the perspectives for the future translation of these pre-clinical approaches into the clinic.
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Affiliation(s)
- Ulrich T. Hacker
- Department of Oncology, Gastroenterology, Hepatology, Pulmonology, and Infectious Diseases, University Cancer Center Leipzig (UCCL), Leipzig University Medical Center, 04103 Leipzig, Germany;
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany; (M.B.); (M.M.)
| | - Martin Bentler
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany; (M.B.); (M.M.)
| | - Dorota Kaniowska
- Department of Oncology, Gastroenterology, Hepatology, Pulmonology, and Infectious Diseases, University Cancer Center Leipzig (UCCL), Leipzig University Medical Center, 04103 Leipzig, Germany;
| | - Michael Morgan
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany; (M.B.); (M.M.)
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
| | - Hildegard Büning
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany; (M.B.); (M.M.)
- REBIRTH Research Center for Translational Regenerative Medicine, Hannover Medical School, 30625 Hannover, Germany
- German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Inhoffenstraße 7, 38124 Braunschweig, Germany
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3
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Büning H, Srivastava A. Capsid Modifications for Targeting and Improving the Efficacy of AAV Vectors. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2019; 12:248-265. [PMID: 30815511 PMCID: PMC6378346 DOI: 10.1016/j.omtm.2019.01.008] [Citation(s) in RCA: 155] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the past decade, recombinant vectors based on a non-pathogenic parvovirus, the adeno-associated virus (AAV), have taken center stage as a gene delivery vehicle for the potential gene therapy for a number of human diseases. To date, the safety of AAV vectors in 176 phase I, II, and III clinical trials and their efficacy in at least eight human diseases are now firmly documented. Despite these remarkable achievements, it has also become abundantly clear that the full potential of first generation AAV vectors composed of naturally occurring capsids is not likely to be realized, since the wild-type AAV did not evolve for the purpose of therapeutic gene delivery. In this article, we provide a brief historical account of the progress that has been made in the development of capsid-modified, next-generation AAV vectors to ensure both the safety and efficacy of these vectors in targeting a wide variety of human diseases.
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Affiliation(s)
- Hildegard Büning
- Institute of Experimental Hematology, Hannover Medical School, Hannover, Germany.,REBIRTH Cluster of Excellence, Hannover Medical School, Hannover, Germany
| | - Arun Srivastava
- Division of Cellular and Molecular Therapy, Departments of Pediatrics and Molecular Genetics & Microbiology, Powell Gene Therapy Center, University of Florida College of Medicine, Gainesville, FL, USA
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4
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Brown N, Song L, Kollu NR, Hirsch ML. Adeno-Associated Virus Vectors and Stem Cells: Friends or Foes? Hum Gene Ther 2018; 28:450-463. [PMID: 28490211 DOI: 10.1089/hum.2017.038] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The infusion of healthy stem cells into a patient-termed "stem-cell therapy"-has shown great promise for the treatment of genetic and non-genetic diseases, including mucopolysaccharidosis type 1, Parkinson's disease, multiple sclerosis, numerous immunodeficiency disorders, and aplastic anemia. Stem cells for cell therapy can be collected from the patient (autologous) or collected from another "healthy" individual (allogeneic). The use of allogenic stem cells is accompanied with the potentially fatal risk that the transplanted donor T cells will reject the patient's cells-a process termed "graft-versus-host disease." Therefore, the use of autologous stem cells is preferred, at least from the immunological perspective. However, an obvious drawback is that inherently as "self," they contain the disease mutation. As such, autologous cells for use in cell therapies often require genetic "correction" (i.e., gene addition or editing) prior to cell infusion and therefore the requirement for some form of nucleic acid delivery, which sets the stage for the AAV controversy discussed herein. Despite being the most clinically applied gene delivery context to date, unlike other more concerning integrating and non-integrating vectors such as retroviruses and adenovirus, those based on adeno-associated virus (AAV) have not been employed in the clinic. Furthermore, published data regarding AAV vector transduction of stem cells are inconsistent in regards to vector transduction efficiency, while the pendulum swings far in the other direction with demonstrations of AAV vector-induced toxicity in undifferentiated cells. The variation present in the literature examining the transduction efficiency of AAV vectors in stem cells may be due to numerous factors, including inconsistencies in stem-cell collection, cell culture, vector preparation, and/or transduction conditions. This review summarizes the controversy surrounding AAV vector transduction of stem cells, hopefully setting the stage for future elucidation and eventual therapeutic applications.
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Affiliation(s)
- Nolan Brown
- 1 Gene Therapy Center, University of North Carolina at Chapel Hill , North Carolina.,2 Department of Ophthalmology, University of North Carolina at Chapel Hill , North Carolina
| | - Liujiang Song
- 1 Gene Therapy Center, University of North Carolina at Chapel Hill , North Carolina.,2 Department of Ophthalmology, University of North Carolina at Chapel Hill , North Carolina
| | - Nageswara R Kollu
- 1 Gene Therapy Center, University of North Carolina at Chapel Hill , North Carolina.,2 Department of Ophthalmology, University of North Carolina at Chapel Hill , North Carolina
| | - Matthew L Hirsch
- 1 Gene Therapy Center, University of North Carolina at Chapel Hill , North Carolina.,2 Department of Ophthalmology, University of North Carolina at Chapel Hill , North Carolina
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5
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Optimization of design and production strategies for novel adeno-associated viral display peptide libraries. Gene Ther 2017. [PMID: 28622288 DOI: 10.1038/gt.2017.51] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Libraries displaying random peptides on the surface of adeno-associated virus (AAV) are powerful tools for the generation of target-specific gene therapy vectors. However, for unknown reasons the success rate of AAV library screenings is variable and the influence of the production procedure has not been thoroughly evaluated. During library screenings, the capsid variants with the most favorable tropism are enriched over several selection rounds on a target of choice and identified by subsequent sequencing of the encapsidated viral genomes encoding the library capsids with targeting peptide insertions. Thus, a high capsid-genome correlation is crucial to obtain the correct information about the selected capsid variants. Producing AAV libraries by a two-step protocol with pseudotyped library transfer shuttles has been proposed as one way to ensure such a correlation. Here we show that AAV2 libraries produced by such a protocol via transfer shuttles display an unexpected additional bias in the amino-acid composition which confers increased heparin affinity and thus similarity to wildtype AAV2 tropism. This bias may fundamentally impair the intended use of AAV libraries, discouraging the use of transfer shuttles for the production of AAV libraries in the future.
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Abstract
Directed evolution represents an attractive approach to derive AAV capsid variants capable of selectively infect specific tissue or cell targets. It involves the generation of an initial library of high complexity followed by cycles of selection during which the library is progressively enriched for target-specific variants. Each selection cycle consists of the following: reconstitution of complete AAV genomes within plasmid molecules; production of virions for which each particular capsid variant is matched with the particular capsid gene encoding it; recovery of capsid gene sequences from target tissue after systemic administration. Prevalent variants are then analyzed and evaluated.
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Affiliation(s)
- Damien Marsic
- Department of Pediatrics, College of Medicine, University of Florida, 2033 Mowry Road, CGRC 235, Gainesville, FL, 32610, USA
| | - Sergei Zolotukhin
- Department of Pediatrics, College of Medicine, University of Florida, 2033 Mowry Road, CGRC 235, Gainesville, FL, 32610, USA.
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Buchholz CJ, Friedel T, Büning H. Surface-Engineered Viral Vectors for Selective and Cell Type-Specific Gene Delivery. Trends Biotechnol 2015; 33:777-790. [PMID: 26497425 DOI: 10.1016/j.tibtech.2015.09.008] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 09/08/2015] [Accepted: 09/11/2015] [Indexed: 12/12/2022]
Abstract
Recent progress in gene transfer technology enables the delivery of genes precisely to the application-relevant cell type ex vivo on cultivated primary cells or in vivo on local or systemic administration. Gene vectors based on lentiviruses or adeno-associated viruses can be engineered such that they use a cell surface marker of choice for cell entry instead of their natural receptors. Binding to the surface marker is mediated by a targeting ligand displayed on the vector particle surface, which can be a peptide, single-chain antibody, or designed ankyrin repeat protein. Examples include vectors that deliver genes to specialized endothelial cells or lymphocytes, tumor cells, or particular cells of the nervous system with potential applications in gene function studies and molecular medicine.
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Affiliation(s)
- Christian J Buchholz
- Paul-Ehrlich-Institut, 63225 Langen, Germany; German Cancer Consortium, 69120 Heidelberg, Germany.
| | | | - Hildegard Büning
- Institute of Experimental Hematology, Hannover Medical School, 30625 Hannover, Germany; Center for Molecular Medicine Cologne (CMMC), University of Cologne, 50931 Cologne, Germany; German Center for Infection Research (DZIF), partner sites Bonn-Cologne and Hannover-Braunschweig, Germany
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8
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Büning H, Huber A, Zhang L, Meumann N, Hacker U. Engineering the AAV capsid to optimize vector–host-interactions. Curr Opin Pharmacol 2015; 24:94-104. [DOI: 10.1016/j.coph.2015.08.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 08/03/2015] [Accepted: 08/05/2015] [Indexed: 12/15/2022]
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Abstract
Gene therapy vectors based on adeno-associated virus (AAV) are currently in clinical trials for numerous disease targets, such as muscular dystrophy, hemophilia, Parkinson's disease, Leber's congenital amaurosis and macular degeneration. Despite its considerable promise and emerging clinical success, several challenges impede the broader implementation of AAV gene therapy, including the prevalence of neutralizing antibodies in the human population, low transduction of a number of therapeutically relevant cell and tissue types, an inability to overcome physical and cellular barriers in vivo and a relatively limited carrying capacity. These challenges arise as the demands we place on AAV vectors are often different from or even at odds with the properties nature bestowed on their parent viruses. Viral-directed evolution-the iterative generation of large, diverse libraries of viral mutants and selection for variants with specific properties of interest-offers an approach to address these problems. Here we outline progress in creating novel classes of AAV variant libraries and highlight the successful isolation of variants with novel and advantageous in vitro and in vivo gene delivery properties.
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10
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Dickey DD, Excoffon KJDA, Koerber JT, Bergen J, Steines B, Klesney-Tait J, Schaffer DV, Zabner J. Enhanced sialic acid-dependent endocytosis explains the increased efficiency of infection of airway epithelia by a novel adeno-associated virus. J Virol 2011; 85:9023-30. [PMID: 21697483 PMCID: PMC3165813 DOI: 10.1128/jvi.05154-11] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 06/08/2011] [Indexed: 11/20/2022] Open
Abstract
We previously used directed evolution in human airway epithelia to create adeno-associated virus 2.5T (AAV2.5T), a highly infectious chimera of AAV2 and AAV5 with one point mutation (A581T). We hypothesized that the mechanism for its increased infection may be a higher binding affinity to the surface of airway epithelia than its parent AAV5. Here, we show that, like AAV5, AAV2.5T, uses 2,3N-linked sialic acid as its primary receptor; however, AAV2.5T binds to the apical surface of human airway epithelia at higher levels and has more receptors than AAV5. Furthermore, its binding affinity is similar to that of AAV5. An alternative hypothesis is that AAV2.5T interaction with 2,3N-linked sialic acid may instead be required for cellular internalization. Consistent with this, AAV2.5T binds but fails to be internalized by CHO cells that lack surface expression of sialic acid. Moreover, whereas AAV2.5T binds similarly to human (rich in 2,3N-linked sialic acid) and pig airway epithelia (2,6N-linked sialic acid), significantly more virus was internalized by human airway. Subsequent transduction correlated with the level of internalized rather than surface-bound virus. We also found that human airway epithelia internalized significantly more AAV2.5T than AAV5. These data suggest that AAV2.5T has evolved to utilize specific 2,3N-linked sialic acid residues on the surface of airway epithelia that mediate rapid internalization and subsequent infection. Thus, sialic acid serves as not just an attachment factor but is also required for AAV2.5T internalization, possibly representing an important rate-limiting step for other viruses that use sialic acids.
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Affiliation(s)
- David D. Dickey
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | | | - James T. Koerber
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462
| | - Jamie Bergen
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462
| | - Benjamin Steines
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - Julia Klesney-Tait
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
| | - David V. Schaffer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720-1462
| | - Joseph Zabner
- Department of Internal Medicine, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242
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12
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Sellner L, Veldwijk MR, Kleinschmidt JA, Laufs S, Topaly J, Fruehauf S, Zeller WJ, Wenz F. Efficient gene transfer with pseudotyped recombinant adeno-associated viral vectors into human chronic myelogenous leukemia cells. Leuk Lymphoma 2011; 52:483-90. [PMID: 21323526 DOI: 10.3109/10428194.2010.545460] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Gene transfer into chronic myelogenous leukemia (CML) cells may become of relevance for overcoming therapy resistance. Single-stranded pseudotyped adeno-associated viruses of serotypes 2/1 to 2/6 (ssAAV2/1-ssAAV2/6) were screened on human CML cell lines and primary cells to determine gene transfer efficiency. Additionally, double-stranded self-complementary vectors (dsAAVs) were used to determine possible second-strand synthesis limitations. On human CML cell lines, ssAAV2/2 and ssAAV2/6 were most efficient. On primary cells, ssAAV2/6 proved significantly more efficient (4.1 ± 2.5% GFP(+) cells, p = 0.011) than the other vectors (<1%). The transduction efficiency could be significantly increased (45.5 ± 13.4%) by using dsAAV2/6 vectors (p < 0.001 vs. ssAAV2/6). In these settings, our data suggest conversion of single- to double-stranded DNA and cell binding/entry as rate-limiting steps. Furthermore, gene transfer was observed in both late and earlier CML (progenitor) populations. For the first time, efficient AAV gene transfer into human CML cells could be shown, with the potential for future clinical application.
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Affiliation(s)
- Leopold Sellner
- Pharmacology of Cancer Treatment, German Cancer Research Center, Heidelberg, Germany
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Adachi K, Nakai H. A NEW RECOMBINANT ADENO-ASSOCIATED VIRUS (AAV)-BASED RANDOM PEPTIDE DISPLAY LIBRARY SYSTEM: INFECTION-DEFECTIVE AAV1.9-3 AS A NOVEL DETARGETED PLATFORM FOR VECTOR EVOLUTION. GENE THERAPY AND REGULATION 2010; 5:31-55. [PMID: 21603583 PMCID: PMC3095953 DOI: 10.1142/s1568558610000197] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Directed evolution through genetic engineering of viral capsids followed by selection has emerged as a powerful means to create novel recombinant adeno-associated virus (rAAV) vectors with desired tropism and enhanced properties. One of the most effective approaches uses rAAV-based random peptide display libraries. Here we report a novel system based on an infection-defective rAAV1.9-3 as a platform for random peptide display, and show that biopanning of the libraries in vitro effectively identifies the peptides that restore and enhance rAAV transduction. rAAV1.9-3 has a genetically engineered AAV1 capsid with amino acids 445-568 being replaced with those of AAV9, and has been identified as a variant exhibiting significantly impaired infectivity and delayed blood clearance when infused into mice. In this study, we generated rAAV1.9-3 variant libraries in which 7- or 12-mer random peptides were expressed at the capsid amino acid position 590. Three rounds of positive selection for primary human dermal fibroblasts successfully identified new rAAV-peptide variants that transduce them more efficiently than the prototype rAAV2. Thus our study demonstrates that an infection-defective rAAV variant serves as a novel detargeted platform for random peptide display libraries. We also describe a brief review of recent progress in rAAV-based random peptide display library approaches.
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Affiliation(s)
- Kei Adachi
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
| | - Hiroyuki Nakai
- Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15219, USA
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14
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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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15
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Veldwijk MR, Sellner L, Stiefelhagen M, Kleinschmidt JA, Laufs S, Topaly J, Fruehauf S, Zeller WJ, Wenz F. Pseudotyped recombinant adeno-associated viral vectors mediate efficient gene transfer into primary human CD34(+) peripheral blood progenitor cells. Cytotherapy 2010; 12:107-12. [PMID: 19929455 DOI: 10.3109/14653240903348293] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND AND AIMS Because of their pluripotency, human CD34(+) peripheral blood progenitor cells (PBPC) are targets of interest for the treatment of many acquired and inherited disorders using gene therapeutic approaches. Unfortunately, most current vector systems lack either sufficient transduction efficiency or an appropriate safety profile. Standard single-stranded recombinant adeno-associated virus 2 (AAV2)-based vectors offer an advantageous safety profile, yet lack the required efficiency in human PBPC. METHODS A panel of pseudotyped AAV vectors (designated AAV2/x, containing the vector genome of serotype 2 and capsid of serotype x, AAV2/1-AAV2/6) was screened on primary human granulocyte-colony-stimulating factor (G-CSF)-mobilized CD34(+) PBPC to determine their gene transfer efficacy. Additionally, double-stranded self-complementary AAV (dsAAV) were used to determine possible second-strand synthesis limitations. RESULTS AAV2/6 vectors proved to be the most efficient [12.8% (1.8-25.4%) transgene-expressing PBPC after a single transduction], being significantly more efficient (all P<0.005) than the other vectors [AAV2/2, 2.0% (0.2-7.3%); AAV2/1, 1.3% (0.1-2.9%); others, <; 1% transgene-expressing PBPC]. In addition, the relevance of the single-to-double-strand conversion block in transduction of human PBPC could be shown using pseudotyped dsAAV vectors: for dsAAV2/2 [9.3% (8.3-20.3%); P<0.001] and dsAAV2/6 [37.7% (23.6-61.0%); P<0.001) significantly more PBPC expressed the transgene compared with their single-stranded counterparts; for dsAAV2/1, no significant increase could be observed. CONCLUSIONS We have shown that clinically relevant transduction efficiency levels using AAV-based vectors in human CD34(+) PBPC are feasible, thereby offering an efficient alternative vector system for gene transfer into this important target cell population.
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Affiliation(s)
- Marlon R Veldwijk
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany.
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16
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Michelfelder S, Trepel M. Adeno-associated viral vectors and their redirection to cell-type specific receptors. ADVANCES IN GENETICS 2010; 67:29-60. [PMID: 19914449 DOI: 10.1016/s0065-2660(09)67002-4] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Efficient and specific delivery of genes to the cell type of interest is a crucial issue in gene therapy. Adeno-associated virus (AAV) has gained particular interest as gene vector recently and is therefore the focus of this chapter. Its low frequency of random integration into the genome and the moderate immune response make AAV an attractive platform for vector design. Like in most other vector systems, the tropism of AAV vectors limits their utility for certain tissues especially upon systemic application. This may in part be circumvented by using AAV serotypes with an in vivo gene transduction pattern most closely fitting the needs of the application. Also, the tropism of AAV capsids may be changed by combining parts of the natural serotype diversity. In addition, peptides mediating binding to the cell type of interest can be identified by random phage display library screening and subsequently be introduced into an AAV capsid region critical for receptor binding. Such peptide insertions can abrogate the natural tropism of AAV capsids and result in detargeting from the liver in vivo. In a novel approach, cell type-directed vector capsids can be selected from random peptide libraries displayed on viral capsids or serotype-shuffling libraries in vitro and in vivo for optimized transduction of the cell type or tissue of interest.
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Affiliation(s)
- Stefan Michelfelder
- Department of Oncology and Hematology, Hubertus Wald Cancer Center, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
| | - Martin Trepel
- Department of Oncology and Hematology, Hubertus Wald Cancer Center, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, D-20246 Hamburg, Germany
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Veldwijk MR, Herskind C, Sellner L, Radujkovic A, Laufs S, Fruehauf S, Zeller WJ, Wenz F. Normal-tissue radioprotection by overexpression of the copper-zinc and manganese superoxide dismutase genes. Strahlenther Onkol 2009; 185:517-23. [PMID: 19652935 DOI: 10.1007/s00066-009-1973-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 05/11/2009] [Indexed: 12/14/2022]
Abstract
BACKGROUND AND PURPOSE Protection of normal tissue against radiation-induced damage may increase the therapeutic ratio of radiotherapy. A promising strategy for testing this approach is gene therapy-mediated overexpression of the copper-zinc (CuZnSOD) or manganese superoxide dismutase (MnSOD) using recombinant adeno-associated viral (rAAV2) vectors. The purpose of this study was to test the modulating effects of the SOD genes on human primary lung fibroblasts (HPLF) after irradiation. MATERIAL AND METHODS HPLF were transduced with rAAV2 vectors containing cDNA for the CuZnSOD, MnSOD or a control gene. The cells were irradiated (1-6 Gy), and gene transfer efficiency, apoptosis, protein expression/activity, and radiosensitivity measured by the colony-forming assay determined. RESULTS After transduction, 90.0% +/- 6.4% of the cells expressed the transgene. A significant fivefold overexpression of both SOD was confirmed by an SOD activity assay (control: 21.1 +/- 12.6, CuZnSOD: 95.1 +/- 17.1, MnSOD: 108.5 +/- 36.0 U SOD/mg protein) and immunohistochemistry. CuZnSOD and MnSOD overexpression resulted in a significant radioprotection of HPLF compared to controls (surviving fraction [SF] ratio SOD/control > 1): CuZnSOD: 1.18-fold (95% confidence interval [CI]: 1.06-1.32; p = 0.005), MnSOD: 1.23-fold (95% CI: 1.07-1.43; p = 0.01). CONCLUSION Overexpression of CuZnSOD and MnSOD in HPLF mediated an increase in clonogenic survival after irradiation compared to controls. In previous works, a lack of radioprotection in SOD-overexpressing tumor cells was observed. Therefore, the present results suggest that rAAV2 vectors are promising tools for the delivery of radioprotective genes in normal tissue.
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Affiliation(s)
- Marlon R Veldwijk
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
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Michelfelder S, Kohlschütter J, Skorupa A, Pfennings S, Müller O, Kleinschmidt JA, Trepel M. Successful expansion but not complete restriction of tropism of adeno-associated virus by in vivo biopanning of random virus display peptide libraries. PLoS One 2009; 4:e5122. [PMID: 19357785 PMCID: PMC2664470 DOI: 10.1371/journal.pone.0005122] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Accepted: 02/26/2009] [Indexed: 12/30/2022] Open
Abstract
Targeting viral vectors to certain tissues in vivo has been a major challenge in gene therapy. Cell type-directed vector capsids can be selected from random peptide libraries displayed on viral capsids in vitro but so far this system could not easily be translated to in vivo applications. Using a novel, PCR-based amplification protocol for peptide libraries displayed on adeno-associated virus (AAV), we selected vectors for optimized transduction of primary tumor cells in vitro. However, these vectors were not suitable for transduction of the same target cells under in vivo conditions. We therefore performed selections of AAV peptide libraries in vivo in living animals after intravenous administration using tumor and lung tissue as prototype targets. Analysis of peptide sequences of AAV clones after several rounds of selection yielded distinct sequence motifs for both tissues. The selected clones indeed conferred gene expression in the target tissue while gene expression was undetectable in animals injected with control vectors. However, all of the vectors selected for tumor transduction also transduced heart tissue and the vectors selected for lung transduction also transduced a number of other tissues, particularly and invariably the heart. This suggests that modification of the heparin binding motif by target-binding peptide insertion is necessary but not sufficient to achieve tissue-specific transgene expression. While the approach presented here does not yield vectors whose expression is confined to one target tissue, it is a useful tool for in vivo tissue transduction when expression in tissues other than the primary target is uncritical.
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Affiliation(s)
- Stefan Michelfelder
- Department of Hematology and Oncology, University of Freiburg Medical Center, Freiburg, Germany
| | - Johannes Kohlschütter
- University Medical Center Hamburg-Eppendorf, Department of Oncology and Hematology, Hamburg, Germany
| | - Alexandra Skorupa
- Institute for Molecular Medicine and Cell Research, Freiburg, Germany
| | - Sabrina Pfennings
- Institute for Molecular Medicine and Cell Research, Freiburg, Germany
| | - Oliver Müller
- University of Heidelberg, Internal Medicine III, Heidelberg, Germany
| | | | - Martin Trepel
- Department of Hematology and Oncology, University of Freiburg Medical Center, Freiburg, Germany
- Institute for Molecular Medicine and Cell Research, Freiburg, Germany
- University Medical Center Hamburg-Eppendorf, Department of Oncology and Hematology, Hamburg, Germany
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