1
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Fu C, Gobbooru S, Martino AT, Low WK. Production of VP3-only virus-like particles of Adeno-associated virus 2 in E. coli cells. Protein Expr Purif 2024; 220:106502. [PMID: 38754753 DOI: 10.1016/j.pep.2024.106502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 04/24/2024] [Accepted: 05/13/2024] [Indexed: 05/18/2024]
Abstract
Adeno-associated Virus (AAV) is a promising vector for gene therapy. However, few studies have focused on producing virus-like particles (VLPs) of AAV in cells, especially in E. coli. In this study, we describe a method to produce empty VP3-only VLPs of AAV2 in E. coli by co-expressing VP3 and assembly-activating protein (AAP) of AAV2. Although the yields of VLPs produced with our method were low, the VLPs were able to self-assemble in E. coli without the need of in vitro capsid assembly. The produced VLPs were characterized by immunological detection and transmission electron microscopy (TEM). In conclusion, this study demonstrated that capsid assembly of AAV2 is possible in E. coli, and E. coli may be a candidate system for production of VLPs of AAV.
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Affiliation(s)
- Chengyu Fu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA
| | - Shruthi Gobbooru
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA
| | - Ashley T Martino
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA
| | - Woon-Kai Low
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, NY, 11439, USA.
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2
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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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3
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Ye X, Hu Y, Qiu H, Li N. Probe capsid structure stability and dynamics of adeno-associated virus as an important viral vector for gene therapy by hydrogen-deuterium exchange-mass spectrometry. Protein Sci 2024; 33:e5074. [PMID: 38888268 PMCID: PMC11184576 DOI: 10.1002/pro.5074] [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: 01/08/2024] [Revised: 04/14/2024] [Accepted: 05/25/2024] [Indexed: 06/20/2024]
Abstract
Adeno-associated virus (AAV), a widely used gene therapy vector, is a small, nonenveloped virus that contains a single-stranded DNA genome with a maximum length of 4.7 kb. Despite extensive biophysical and structural characterization, many aspects of AAV functions remain elusive. This knowledge gap is primarily due to a lack of structurally resolved dynamic information and the absence of structural coverage of functionally critical segments on the AAV capsid. Here, we developed a protocol to study AAV structural dynamics by hydrogen-deuterium exchange mass spectrometry (HDX-MS), a powerful method for monitoring protein structure stability and dynamics in solution. We performed HDX-MS measurements on AAVs without or with different DNA payloads of different sizes, and obtained detailed dynamic information on the entire AAV sequence including the two functionally important segments not previously structurally characterized. The unique N terminus of the capsid protein VP1 (VP1u) was found to adopt a highly dynamic and unstable conformation with low HDX protection across the entire region, whereas the presence of a DNA payload increased its protection. The VP1 and VP2 shared region (VP1/2) showed no measurable protection, with or without DNA. Differential HDX between empty and full capsid samples allowed us to identify potential new DNA-capsid interaction sites located primarily around the five-fold channel, which differ from the three-fold pocket binding site previously identified. Our HDX-MS method for characterizing AAV structural dynamics opens a new way for future efforts to understand AAV structure-function relationships and engineer next-generation AAV vectors with improved gene delivery properties.
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Affiliation(s)
- Xiang Ye
- Regeneron Pharmaceuticals, Inc.TarrytownNew YorkUSA
| | - Yunli Hu
- Regeneron Pharmaceuticals, Inc.TarrytownNew YorkUSA
| | - Haibo Qiu
- Regeneron Pharmaceuticals, Inc.TarrytownNew YorkUSA
| | - Ning Li
- Regeneron Pharmaceuticals, Inc.TarrytownNew YorkUSA
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4
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Mietzsch M, Nelson AR, Hsi J, Zachary J, Potts L, Chipman P, Ghanem M, Khandekar N, Alexander IE, Logan GJ, Huiskonen JT, McKenna R. Structural characterization of antibody-responses from Zolgensma treatment provides the blueprint for the engineering of an AAV capsid suitable for redosing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.01.590489. [PMID: 38746165 PMCID: PMC11092599 DOI: 10.1101/2024.05.01.590489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2024]
Abstract
Monoclonal antibodies (mAbs) are useful tools to dissect the neutralizing antibody response against the adeno-associated virus (AAV) capsids used as gene therapy delivery vectors. This study structurally characterizes the interactions of 21 human-derived antibodies from patients treated with the AAV9 vector, Zolgensma ® , utilizing high-resolution cryo-electron microscopy. The majority of the bound antibodies do not conform to the icosahedral symmetry of the capsid, thus requiring localized reconstructions. These complex structures provide unprecedented details of the mAbs binding interfaces, with some antibodies inducing structural perturbations of the capsid upon binding. Key surface capsid amino acid residues were identified facilitating the design of capsid variants with an antibody escape phenotype, with the potential to expand the patient cohort treatable with AAV9 vectors to include those that were previously excluded due to their pre-existing neutralizing antibodies, and possibly also to those requiring redosing.
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5
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Lopes JA, Garnier NE, Pei Y, Yates JGE, Campbell ESB, Goens MM, Hughes ME, Rghei AD, Stevens BAY, Guilleman MM, Thompson B, Khursigara CM, Susta L, Wootton SK. AAV-vectored expression of monospecific or bispecific monoclonal antibodies protects mice from lethal Pseudomonas aeruginosa pneumonia. Gene Ther 2024:10.1038/s41434-024-00453-1. [PMID: 38678160 DOI: 10.1038/s41434-024-00453-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 04/08/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024]
Abstract
Pseudomonas aeruginosa poses a significant threat to immunocompromised individuals and those with cystic fibrosis. Treatment relies on antibiotics, but persistent infections occur due to intrinsic and acquired resistance of P. aeruginosa towards multiple classes of antibiotics. To date, there are no licensed vaccines for this pathogen, prompting the urgent need for novel treatment approaches to combat P. aeruginosa infection and persistence. Here we validated AAV vectored immunoprophylaxis as a strategy to generate long-term plasma and mucosal expression of highly protective monoclonal antibodies (mAbs) targeting the exopolysaccharide Psl (Cam-003) and the PcrV (V2L2MD) component of the type-III secretion system injectosome either as single mAbs or together as a bispecific mAb (MEDI3902) in a mouse model. When administered intramuscularly, AAV-αPcrV, AAV-αPsl, and AAV-MEDI3902 significantly protected mice challenged intranasally with a lethal dose of P. aeruginosa strains PAO1 and PA14 and reduced bacterial burden and dissemination to other organs. While all AAV-mAbs provided protection, AAV-αPcrV and AAV-MEDI3902 provided 100% and 87.5% protection from a lethal challenge with 4.47 × 107 CFU PAO1 and 87.5% and 75% protection from a lethal challenge with 3 × 107 CFU PA14, respectively. Serum concentrations of MEDI3902 were ~10× lower than that of αPcrV, but mice treated with this vector showed a greater reduction in bacterial dissemination to the liver, lung, spleen, and blood compared to other AAV-mAbs. These results support further investigation into the use of AAV vectored immunoprophylaxis to prevent and treat P. aeruginosa infections and other bacterial pathogens of public health concern for which current treatment strategies are limited.
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Affiliation(s)
- Jordyn A Lopes
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Nicole E Garnier
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Yanlong Pei
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Jacob G E Yates
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Elena S B Campbell
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Melanie M Goens
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Madison E Hughes
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Amira D Rghei
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Brenna A Y Stevens
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Matthew M Guilleman
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Brad Thompson
- Avamab Pharma Inc., 120, 4838 Richard Road SW, Calgary, AB, T3E 6L1, Canada
| | - Cezar M Khursigara
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Leonardo Susta
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada
| | - Sarah K Wootton
- Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
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6
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Park S, Shin S, Lee H, Jang JH, Lee GM. Enhancing the production of adeno-associated virus (AAV)2 and AAV9 with high full capsid ratio in HEK293 cells through design-of-experiment optimization of triple plasmid ratio. Biotechnol J 2024; 19:e2300667. [PMID: 38479987 DOI: 10.1002/biot.202300667] [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: 11/26/2023] [Revised: 02/02/2024] [Accepted: 02/27/2024] [Indexed: 03/17/2024]
Abstract
The recombinant adeno-associated virus (rAAV) vectors used in gene therapy are usually produced by transfecting three different plasmids (Adenoviral helper plasmid (pHelper), AAV rep/cap plasmids (pRepCap), and Transgene plasmid (pAAV-GOI)) into human embryonic kidney 293 (HEK293) cells. However, the high proportion of unwanted empty capsids generated during rAAV production is problematic. To simultaneously enhance the genome titer and full capsid ratio, the ratio of the three plasmids transfected into HEK293 cells was optimized using design-of-experiment (DoE). AAV2 and AAV9, which have different production kinetics, were selected as cell-associated and secreted model AAVs, respectively. In 125 mL Erlenmeyer flasks, the genome titers of rAAV2 and rAAV9 at DoE-optimized plasmid weight ratios (pHelper:pRep2Cap2:pAAV-GOI = 1:3.52:0.50 for rAAV2 and pHelper:pRep2Cap9:pAAV-GOI = 1:1.44:0.27 for rAAV9) were 2.23-fold and 2.26-fold higher than those in the widely used plasmid weight ratio (1:1:1), respectively. In addition, compared with the plasmid ratio of 1:1:1, the relative VP3 band intensities of rAAV2 and rAAV9, which represent the relative empty capsid ratios, were reduced by 26% and 25%, respectively, at the DoE-optimized plasmid ratio. Reduced empty capsid ratios in the DoE-optimized plasmid ratios were also confirmed using transmission electron microscopy (TEM). Taken together, regardless of the AAV serotype, DoE-aided optimization of the triple plasmid ratio was found to be an efficient means of improving the production of rAAV with a high full capsid ratio.
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Affiliation(s)
- Sungje Park
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Seunghyeon Shin
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
| | - Haeshin Lee
- Department of Chemistry, KAIST, Daejeon, Republic of Korea
| | - Jae-Hyung Jang
- Department of Chemical and Biomolecular Engineering, Yonsei University, Seoul, Republic of Korea
- R&D Center, GluGene Therapeutics Inc., Seoul, Republic of Korea
| | - Gyun Min Lee
- Department of Biological Sciences, KAIST, Daejeon, Republic of Korea
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7
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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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8
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Wang Y, Fu Q, Park SY, Lee YS, Park SY, Lee DY, Yoon S. Decoding cellular mechanism of recombinant adeno-associated virus (rAAV) and engineering host-cell factories toward intensified viral vector manufacturing. Biotechnol Adv 2024; 71:108322. [PMID: 38336188 DOI: 10.1016/j.biotechadv.2024.108322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 01/22/2024] [Accepted: 02/06/2024] [Indexed: 02/12/2024]
Abstract
Recombinant adeno-associated virus (rAAV) is one of the prominent gene delivery vehicles that has opened promising opportunities for novel gene therapeutic approaches. However, the current major viral vector production platform, triple transfection in mammalian cells, may not meet the increasing demand. Thus, it is highly required to understand production bottlenecks from the host cell perspective and engineer the cells to be more favorable and tolerant to viral vector production, thereby effectively enhancing rAAV manufacturing. In this review, we provided a comprehensive exploration of the intricate cellular process involved in rAAV production, encompassing various stages such as plasmid entry to the cytoplasm, plasmid trafficking and nuclear delivery, rAAV structural/non-structural protein expression, viral capsid assembly, genome replication, genome packaging, and rAAV release/secretion. The knowledge in the fundamental biology of host cells supporting viral replication as manufacturing factories or exhibiting defending behaviors against viral production is summarized for each stage. The control strategies from the perspectives of host cell and materials (e.g., AAV plasmids) are proposed as our insights based on the characterization of molecular features and our existing knowledge of the AAV viral life cycle, rAAV and other viral vector production in the Human embryonic kidney (HEK) cells.
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Affiliation(s)
- Yongdan Wang
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, United States of America
| | - Qiang Fu
- Department of Biomedical Engineering and Biotechnology, University of Massachusetts Lowell, Lowell, MA 01854, United States of America
| | - So Young Park
- Department of Pharmaceutical Sciences, University of Massachusetts Lowell, Lowell, MA 01854, United States of America
| | - Yong Suk Lee
- Department of Pharmaceutical Sciences, University of Massachusetts Lowell, Lowell, MA 01854, United States of America
| | - Seo-Young Park
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea
| | - Dong-Yup Lee
- School of Chemical Engineering, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon, Gyeonggi-do 16419, Republic of Korea
| | - Seongkyu Yoon
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, MA 01854, United States of America.
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9
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Blasiak J, Pawlowska E, Ciupińska J, Derwich M, Szczepanska J, Kaarniranta K. A New Generation of Gene Therapies as the Future of Wet AMD Treatment. Int J Mol Sci 2024; 25:2386. [PMID: 38397064 PMCID: PMC10888617 DOI: 10.3390/ijms25042386] [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: 01/19/2024] [Revised: 02/14/2024] [Accepted: 02/16/2024] [Indexed: 02/25/2024] Open
Abstract
Age-related macular degeneration (AMD) is an eye disease and the most common cause of vision loss in the Western World. In its advanced stage, AMD occurs in two clinically distinguished forms, dry and wet, but only wet AMD is treatable. However, the treatment based on repeated injections with vascular endothelial growth factor A (VEGFA) antagonists may at best stop the disease progression and prevent or delay vision loss but without an improvement of visual dysfunction. Moreover, it is a serious mental and financial burden for patients and may be linked with some complications. The recent first success of intravitreal gene therapy with ADVM-022, which transformed retinal cells to continuous production of aflibercept, a VEGF antagonist, after a single injection, has opened a revolutionary perspective in wet AMD treatment. Promising results obtained so far in other ongoing clinical trials support this perspective. In this narrative/hypothesis review, we present basic information on wet AMD pathogenesis and treatment, the concept of gene therapy in retinal diseases, update evidence on completed and ongoing clinical trials with gene therapy for wet AMD, and perspectives on the progress to the clinic of "one and done" therapy for wet AMD to replace a lifetime of injections. Gene editing targeting the VEGFA gene is also presented as another gene therapy strategy to improve wet AMD management.
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Affiliation(s)
- Janusz Blasiak
- Faculty of Medicine, Collegium Medicum, Mazovian Academy in Plock, 09-402 Plock, Poland
| | - Elzbieta Pawlowska
- Department of Pediatric Dentistry, Medical University of Lodz, 92-217 Lodz, Poland; (E.P.); (M.D.); (J.S.)
| | - Justyna Ciupińska
- Clinical Department of Infectious Diseases and Hepatology, H. Bieganski Hospital, 91-347 Lodz, Poland;
| | - Marcin Derwich
- Department of Pediatric Dentistry, Medical University of Lodz, 92-217 Lodz, Poland; (E.P.); (M.D.); (J.S.)
| | - Joanna Szczepanska
- Department of Pediatric Dentistry, Medical University of Lodz, 92-217 Lodz, Poland; (E.P.); (M.D.); (J.S.)
| | - Kai Kaarniranta
- Department of Ophthalmology, University of Eastern Finland, 70210 Kuopio, Finland;
- Department of Ophthalmology, Kuopio University Hospital, 70210 Kuopio, Finland
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10
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Li X, Miller LM, Chrzanowski M, Tian J, Jarrold MF, Herzog RW, Xiao W, Draper B, Zhang J. Quantitative analysis of preferential utilization of AAV ITR as the packaging terminal signal. Front Bioeng Biotechnol 2023; 11:1327433. [PMID: 38173872 PMCID: PMC10761532 DOI: 10.3389/fbioe.2023.1327433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 12/05/2023] [Indexed: 01/05/2024] Open
Abstract
Genetic engineering advances have led to recombinant adeno-associated virus (rAAV) becoming an invaluable tool for the development of effective gene therapies. The production of rAAV is susceptible to off-target heterogeneous packaging, the effects of which are still being understood. Here, rAAV vectors with four-genome lengths were produced using both adherent and suspension HEK293 cells to understand the 5'ITR termination. AAV8 vectors were produced from the human FVIII plasmid for a full-length cargo of 4,707 nucleotides with specific truncations, creating smaller genomes. Conventionally, rAAV is characterized by differentiating empty capsids from full capsids, but for this work, that description is incomplete. The small genomes in this study were characterized by charge detection-mass spectrometry (CD-MS). Using CD-MS, packaged genomes in the range conventionally attributed to partials were resolved and quantified. In addition, alkaline gels and qPCR were used to assess the identity of the packaged genomes. Together, these results showed a propensity for unit-length genomes to be encapsidated. Packaged genomes occurred as replication intermediates emanating from the 5'ITR, indicating that HEK293 cells prefer unit-length genomes as opposed to the 5'ITR termination and heterogeneous DNA packaging observed previously from Sf9 cell systems. As both manufacturing processes are used and continually assessed to produce clinical material, such an understanding will benefit rAAV design for basic research and gene therapy.
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Affiliation(s)
- Xin Li
- Herman B Wells Center for Pediatric Research, Indiana University IUSM, Indianapolis, IN, United States
| | | | | | - Jiahe Tian
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, United States
| | - Martin F. Jarrold
- Chemistry Department, Indiana University, Bloomington, IN, United States
| | - Roland W. Herzog
- Herman B Wells Center for Pediatric Research, Indiana University IUSM, Indianapolis, IN, United States
| | - Weidong Xiao
- Herman B Wells Center for Pediatric Research, Indiana University IUSM, Indianapolis, IN, United States
| | | | - Junping Zhang
- Herman B Wells Center for Pediatric Research, Indiana University IUSM, Indianapolis, IN, United States
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11
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Madigan V, Zhang F, Dahlman JE. Drug delivery systems for CRISPR-based genome editors. Nat Rev Drug Discov 2023; 22:875-894. [PMID: 37723222 DOI: 10.1038/s41573-023-00762-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/06/2023] [Indexed: 09/20/2023]
Abstract
CRISPR-based drugs can theoretically manipulate any genetic target. In practice, however, these drugs must enter the desired cell without eliciting an unwanted immune response, so a delivery system is often required. Here, we review drug delivery systems for CRISPR-based genome editors, focusing on adeno-associated viruses and lipid nanoparticles. After describing how these systems are engineered and their subsequent characterization in preclinical animal models, we highlight data from recent clinical trials. Preclinical targeting mediated by polymers, proteins, including virus-like particles, and other vehicles that may deliver CRISPR systems in the future is also discussed.
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Affiliation(s)
- Victoria Madigan
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- McGovern Institute for Brain Research at MIT, Cambridge, MA, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
| | - Feng Zhang
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
- McGovern Institute for Brain Research at MIT, Cambridge, MA, USA
- Department of Brain and Cognitive Science, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
- Howard Hughes Medical Institute, Cambridge, MA, USA
| | - James E Dahlman
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University School of Medicine, Atlanta, GA, USA.
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12
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Mietzsch M, Liu W, Ma K, Bennett A, Nelson AR, Gliwa K, Chipman P, Fu X, Bechler S, McKenna R, Viner R. Production and characterization of an AAV1-VP3-only capsid: An analytical benchmark standard. Mol Ther Methods Clin Dev 2023; 29:460-472. [PMID: 37273903 PMCID: PMC10238842 DOI: 10.1016/j.omtm.2023.05.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Accepted: 05/04/2023] [Indexed: 06/06/2023]
Abstract
Adeno-associated viruses (AAVs) are non-enveloped ssDNA icosahedral T = 1 viruses used as vectors for clinical gene delivery. Currently, there are over 200 AAV-related clinical trials and six approved biologics on the market. As such new analytical methods are continually being developed to characterize and monitor the quality and purity of manufactured AAV vectors, these include ion-exchange chromatography and Direct Mass Technology. However, these methods require homogeneous analytical standards with a high molecular weight standard comparable to the mass of an AAV capsid. Described here is the design, production, purification, characterization, and the cryo-electron microscopy structure of an AAV1-VP3-only capsid that fulfills this need as a calibrant to determine capsid mass, charge, homogeneity, and transgene packaging characteristics.
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Affiliation(s)
- Mario Mietzsch
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Weijing Liu
- Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, CA 95134, USA
| | - Ke Ma
- Thermo Fisher Scientific, 490 Lakeside Dr., Sunnyvale, CA 94085, USA
| | - Antonette Bennett
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Austin R. Nelson
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Keely Gliwa
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Paul Chipman
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Xiaofeng Fu
- Biological Science Imaging Resource, Department of Biological Sciences, Florida State University, Tallahassee, FL, USA
| | - Shane Bechler
- Thermo Fisher Scientific, 490 Lakeside Dr., Sunnyvale, CA 94085, USA
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Rosa Viner
- Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, CA 95134, USA
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13
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Xiang YS, Hao GG. Biophysical characterization of adeno-associated virus capsid through the viral transduction life cycle. J Genet Eng Biotechnol 2023; 21:62. [PMID: 37195476 DOI: 10.1186/s43141-023-00518-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/11/2023] [Indexed: 05/18/2023]
Abstract
Adeno-associated virus (AAV) vectors have emerged as the leading delivery platforms for gene therapy. Throughout the life cycle of the virions, the capsid vector carries out diverse functions, ranging from cell surface receptor engagement, cellular entry, endosomal escape, nuclear import to new particle packaging, and assembly. Each of these steps is mediated by exquisite structure features of the viral capsid and its interaction with viral genome, Rep proteins, and cellular organelle and apparatus. In this brief review, we provide an overview of results from over a decade of extensive biophysical studies of the capsid employing various techniques. The remaining unaddressed questions and perspective are also discussed. The detailed understanding of the structure and function interplay would provide insight to the strategy for improving the efficacy and safety of the viral vectors.
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Affiliation(s)
| | - Gang Gary Hao
- Weston Biomedical Reviews, 65 Autumn Road, Weston, MA, 02493, USA.
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14
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Barnes LF, Draper BE, Kurian J, Chen YT, Shapkina T, Powers TW, Jarrold MF. Analysis of AAV-Extracted DNA by Charge Detection Mass Spectrometry Reveals Genome Truncations. Anal Chem 2023; 95:4310-4316. [PMID: 36880264 DOI: 10.1021/acs.analchem.2c04234] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Adeno-associated virus (AAV) is a widely used gene therapy vector. The intact packaged genome is a critical quality attribute and necessary for an effective therapeutic. In this work, charge detection mass spectrometry (CDMS) was used to measure the molecular weight (MW) distribution for the genome of interest (GOI) extracted from recombinant AAV (rAAV) vectors. The measured MWs were compared to sequence masses for a range of rAAV vectors with different GOIs, serotypes, and production methods (Sf9 and HEK293 cell lines). In most cases, the measured MWs were slightly larger than the sequence masses, a result attributed to counterions. However, in a few cases, the measured MWs were significantly smaller than the sequence masses. In these cases, genome truncation is the only reasonable explanation for the discrepancy. These results suggest that direct analysis of the extracted GOI by CDMS provides a rapid and powerful tool to evaluate genome integrity in gene therapy products.
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Affiliation(s)
- Lauren F Barnes
- Chemistry Department, Indiana University, 800 E Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Benjamin E Draper
- Chemistry Department, Indiana University, 800 E Kirkwood Avenue, Bloomington, Indiana 47405, United States
| | - Justin Kurian
- Analytical Research and Development, Pfizer Inc., 875 Chesterfield Pkwy. West, Chesterfield, Missouri 63017, United States
| | - Yu-Ting Chen
- Analytical Research and Development, Pfizer Inc., 875 Chesterfield Pkwy. West, Chesterfield, Missouri 63017, United States
| | - Tatiana Shapkina
- Analytical Research and Development, Pfizer Inc., 875 Chesterfield Pkwy. West, Chesterfield, Missouri 63017, United States
| | - Thomas W Powers
- Analytical Research and Development, Pfizer Inc., 875 Chesterfield Pkwy. West, Chesterfield, Missouri 63017, United States
| | - Martin F Jarrold
- Chemistry Department, Indiana University, 800 E Kirkwood Avenue, Bloomington, Indiana 47405, United States
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15
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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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16
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Emerging Perspectives on Gene Therapy Delivery for Neurodegenerative and Neuromuscular Disorders. J Pers Med 2022; 12:jpm12121979. [PMID: 36556200 PMCID: PMC9788053 DOI: 10.3390/jpm12121979] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/31/2022] [Accepted: 11/07/2022] [Indexed: 12/05/2022] Open
Abstract
Neurodegenerative disorders (NDDs), such as Alzheimer's disease (AD) and Parkinson's Disease (PD), are a group of heterogeneous diseases that mainly affect central nervous system (CNS) functions. A subset of NDDs exhibit CNS dysfunction and muscle degeneration, as observed in Gangliosidosis 1 (GM1) and late stages of PD. Neuromuscular disorders (NMDs) are a group of diseases in which patients show primary progressive muscle weaknesses, including Duchenne Muscular Dystrophy (DMD), Pompe disease, and Spinal Muscular Atrophy (SMA). NDDs and NMDs typically have a genetic component, which affects the physiological functioning of critical cellular processes, leading to pathogenesis. Currently, there is no cure or efficient treatment for most of these diseases. More than 200 clinical trials have been completed or are currently underway in order to establish safety, tolerability, and efficacy of promising gene therapy approaches. Thus, gene therapy-based therapeutics, including viral or non-viral delivery, are very appealing for the treatment of NDDs and NMDs. In particular, adeno-associated viral vectors (AAV) are an attractive option for gene therapy for NDDs and NMDs. However, limitations have been identified after systemic delivery, including the suboptimal capacity of these therapies to traverse the blood-brain barrier (BBB), degradation of the particles during the delivery, high reactivity of the patient's immune system during the treatment, and the potential need for redosing. To circumvent these limitations, several preclinical and clinical studies have suggested intrathecal (IT) delivery to target the CNS and peripheral organs via cerebrospinal fluid (CSF). CSF administration can vastly improve the delivery of small molecules and drugs to the brain and spinal cord as compared to systemic delivery. Here, we review AAV biology and vector design elements, different therapeutic routes of administration, and highlight CSF delivery as an attractive route of administration. We discuss the different aspects of neuromuscular and neurodegenerative diseases, such as pathogenesis, the landscape of mutations, and the biological processes associated with the disease. We also describe the hallmarks of NDDs and NMDs as well as discuss current therapeutic approaches and clinical progress in viral and non-viral gene therapy and enzyme replacement strategies for those diseases.
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17
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Frenkel R, Tribby D, Boumajny B, Larson N, Sampson M, Barney C, Bergelson S, Sosic Z, Yeung B. ACUVRA: Anion-Exchange Chromatography UV-Ratio Analysis-A QC-Friendly Method for Monitoring Adeno-Associated Virus Empty Capsid Content To Support Process Development and GMP Release Testing. AAPS J 2022; 25:3. [PMID: 36414847 DOI: 10.1208/s12248-022-00768-0] [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: 07/06/2022] [Accepted: 10/28/2022] [Indexed: 11/24/2022] Open
Abstract
The genome content of adeno-associated virus (AAV) vectors is critical to the safety and potency of AAV-based gene therapy products. Empty capsids are considered a product-related impurity and a critical quality attribute (CQA) of the drug product, thus requiring characterization throughout the production process to demonstrate they are controlled to acceptable levels in the final drug product. Anion exchange chromatography has been used to achieve separation between empty and full capsids, but requires method development and gradient optimization for different serotypes and formulations. Here, we describe an alternative approach to quantitation that does not rely on achieving separation between empty and full capsids, but instead uses the well-established relationship between absorbance at UV A260/A280 and relation to DNA/protein content, in combination with anion-exchange chromatography to allow one to calculate the relative proportion of empty and full capsids in AAV samples from a single peak. We call this approach ACUVRA: Anion-exchange Chromatography UV-Ratio Analysis, and show the applicability of the method through a case study with recombinant AAV2 (rAAV2) process intermediates and drug substance. Method qualification and GMP validation in a quality control (QC) laboratory results show that ACUVRA is a fit-for-purpose method for process development support and characterization, while also being a QC-friendly option for GMP release testing at all stages of clinical development. Graphical abstract.
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Affiliation(s)
- Ruth Frenkel
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA.
| | - Dana Tribby
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
| | - Boris Boumajny
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
| | - Nicholas Larson
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
| | - Matthew Sampson
- Department of Quality Control-Analytical Technology, Biogen Inc, 5000 Davis Dr, Durham, North Carolina, 27709, USA
| | - Christopher Barney
- Department of Quality Control-Analytical Technology, Biogen Inc, 5000 Davis Dr, Durham, North Carolina, 27709, USA
| | - Svetlana Bergelson
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
| | - Zoran Sosic
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
| | - Bernice Yeung
- Department of Gene Therapy Analytical Development, Biogen Inc, 255 Binney St, Cambridge, Massachusetts, 02142, USA
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18
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Pan X, Yue Y, Boftsi M, Wasala LP, Tran NT, Zhang K, Pintel DJ, Tai PWL, Duan D. Rational engineering of a functional CpG-free ITR for AAV gene therapy. Gene Ther 2022; 29:333-345. [PMID: 34611321 PMCID: PMC8983793 DOI: 10.1038/s41434-021-00296-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/10/2021] [Accepted: 09/15/2021] [Indexed: 12/12/2022]
Abstract
Inverted terminal repeats (ITRs) are the only wild-type components retained in the genome of adeno-associated virus (AAV) vectors. To determine whether ITR modification is a viable approach for AAV vector engineering, we rationally deleted all CpG motifs in the ITR and examined whether CpG elimination compromises AAV-vector production and transduction. Modified ITRs were stable in the plasmid and maintained the CpG-free nature in purified vectors. Replacing the wild-type ITR with the CpG-free ITR did not affect vector genome encapsidation. However, the vector yield was decreased by approximately 3-fold due to reduced vector genome replication. To study the biological potency, we made micro-dystrophin (μDys) AAV vectors carrying either the wild-type ITR or the CpG-free ITR. We delivered the CpG-free μDys vector to one side of the tibialis anterior muscle of dystrophin-null mdx mice and the wild-type μDys vector to the contralateral side. Evaluation at four months after injection showed no difference in the vector genome copy number, microdystrophin expression, and muscle histology and force. Our results suggest that the complete elimination of the CpG motif in the ITR does not affect the biological activity of the AAV vector. CpG-free ITRs could be useful in engineering therapeutic AAV vectors.
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Affiliation(s)
- Xiufang Pan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - Maria Boftsi
- Pathobiology Area Graduate Program, University of Missouri, Columbia, MO, 65212, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65212, USA
| | - Lakmini P Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
- Pathobiology Area Graduate Program, University of Missouri, Columbia, MO, 65212, USA
| | - Ngoc Tam Tran
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, 01605, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
| | - David J Pintel
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA
- Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO, 65212, USA
| | - Phillip W L Tai
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, MA, 01605, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, MA, 01605, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Neurology, School of Medicine, University of Missouri, Columbia, MO, 65212, USA.
- Department of Biomedical, Biological & Chemical Engineering, College of Engineering, University of Missouri, Columbia, MO, 65212, USA.
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19
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Barnes CR, Lee H, Ojala DS, Lewis KK, Limsirichai P, Schaffer DV. Genome-wide activation screens to increase adeno-associated virus production. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:94-103. [PMID: 34513296 PMCID: PMC8413672 DOI: 10.1016/j.omtn.2021.06.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/30/2021] [Indexed: 11/24/2022]
Abstract
We describe a genome-wide screening strategy to identify target genes whose modulation increases the capacity of a cell to produce recombinant adeno-associated viral (AAV) vector. Specifically, a single-guide RNA (sgRNA) library for a CRISPR-based genome-wide transcriptional activation screen was inserted into an AAV vector, and iterative rounds of viral infection and rescue in HEK293 producer cells enabled the enrichment of sgRNAs targeting genes whose upregulation increased AAV production. Numerous gain-of-function targets were identified, including spindle and kinetochore associated complex subunit 2 (SKA2) and inositol 1, 4, 5-trisphosphate receptor interacting protein (ITPRIP). Furthermore, individual or combinatorial modulation of these targets in stable producer cell lines increased vector genomic replication and loading into AAV virions, resulting in up to a 3.8-fold increase in AAV manufacturing capacity. Our study offers an efficient approach to engineer viral vector producer cell lines and enhances our understanding of the roles of SKA2 and ITPRIP in AAV packaging.
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Affiliation(s)
- Christopher R. Barnes
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Hyuncheol Lee
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
| | - David S. Ojala
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Kazuomori K. Lewis
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Prajit Limsirichai
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - David V. Schaffer
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, Berkeley, CA 94720, USA
- California Institute for Quantitative Biosciences (QB3), University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Bioengineering, University of California, Berkeley, Berkeley, CA 94720, USA
- Department of Cell and Molecular Biology, University of California, Berkeley, Berkeley, CA 94720, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
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20
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Mietzsch M, Yu JC, Hsi J, Chipman P, Broecker F, Fuming Z, Linhardt RJ, Seeberger PH, Heilbronn R, McKenna R, Agbandje-McKenna M. Structural Study of Aavrh.10 Receptor and Antibody Interactions. J Virol 2021; 95:e0124921. [PMID: 34549984 PMCID: PMC8577363 DOI: 10.1128/jvi.01249-21] [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: 07/23/2021] [Accepted: 09/13/2021] [Indexed: 11/20/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors are one of the leading tools for the delivery of therapeutic genes in human gene therapy applications. For a successful transfer of their payload, the AAV vectors have to circumvent potential preexisting neutralizing host antibodies and bind to the receptors of the target cells. Both of these aspects have not been structurally analyzed for AAVrh.10. Here, cryo-electron microscopy and three-dimensional image reconstruction were used to map the binding site of sulfated N-acetyllactosamine (LacNAc; previously shown to bind AAVrh.10) and a series of four monoclonal antibodies (MAbs). LacNAc was found to bind to a pocket located on the side of the 3-fold capsid protrusion that is mostly conserved to AAV9 and equivalent to its galactose-binding site. As a result, AAVrh.10 was also shown to be able to bind to cell surface glycans with terminal galactose. For the antigenic characterization, it was observed that several anti-AAV8 MAbs cross-react with AAVrh.10. The binding sites of these antibodies were mapped to the 3-fold capsid protrusions. Based on these observations, the AAVrh.10 capsid surface was engineered to create variant capsids that escape these antibodies while maintaining infectivity. IMPORTANCE Gene therapy vectors based on adeno-associated virus rhesus isolate 10 (AAVrh.10) have been used in several clinical trials to treat monogenetic diseases. However, compared to other AAV serotypes little is known about receptor binding and antigenicity of the AAVrh.10 capsid. Particularly, preexisting neutralizing antibodies against capsids are an important challenge that can hamper treatment efficiency. This study addresses both topics and identifies critical regions of the AAVrh.10 capsid for receptor and antibody binding. The insights gained were utilized to generate AAVrh.10 variants capable of evading known neutralizing antibodies. The findings of this study could further aid the utilization of AAVrh.10 vectors in clinical trials and help the approval of the subsequent biologics.
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Affiliation(s)
- Mario Mietzsch
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Jennifer C. Yu
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Jane Hsi
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Paul Chipman
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Felix Broecker
- Department of Biomolecular Systems, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Zhang Fuming
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Robert J. Linhardt
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York, USA
| | - Peter H. Seeberger
- Department of Biomolecular Systems, Max-Planck Institute of Colloids and Interfaces, Potsdam, Germany
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Regine Heilbronn
- Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health, Berlin, Germany
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
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21
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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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22
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Mietzsch M, Eddington C, Jose A, Hsi J, Chipman P, Henley T, Choudhry M, McKenna R, Agbandje-McKenna M. Improved Genome Packaging Efficiency of Adeno-associated Virus Vectors Using Rep Hybrids. J Virol 2021; 95:e0077321. [PMID: 34287038 PMCID: PMC8428402 DOI: 10.1128/jvi.00773-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 07/03/2021] [Indexed: 01/11/2023] Open
Abstract
Recombinant adeno-associated viruses (rAAVs) are one of the most commonly used vectors for a variety of gene therapy applications. In the last 2 decades, research focused primarily on the characterization and isolation of new cap, genes resulting in hundreds of natural and engineered AAV capsid variants, while the rep gene, the other major AAV open reading frame, has been less studied. This is due to the fact that the rep gene from AAV serotype 2 (AAV2) enables the single-stranded DNA packaging of recombinant genomes into most AAV serotype and engineered capsids. However, a major by-product of all vector productions is empty AAV capsids, lacking the encapsidated vector genome, especially for non-AAV2 vectors. Despite the packaging process being considered the rate-limiting step for rAAV production, none of the rep genes from the other AAV serotypes have been characterized for their packaging efficiency. Thus, in this study AAV2 rep was replaced with the rep gene of a select number of AAV serotypes. However, this led to a lowering of capsid protein expression, relative to the standard AAV2-rep system. In further experiments the 3' end of the AAV2 rep gene was reintroduced to promote increased capsid expression and a series of chimeras between the different AAV Rep proteins were generated and characterized for their vector genome packaging ability. The utilization of these novel Rep hybrids increased the percentage of genome containing (full) capsids approximately 2- to -4-fold for all of the non-AAV2 serotypes tested. Thus, these Rep chimeras could revolutionize rAAV production. IMPORTANCE A major by-product of all adeno-associated virus (AAV) vector production systems are "empty" capsids, void of the desired therapeutic gene, and thus do not provide any curative benefit for the treatment of the targeted disease. In fact, empty capsids can potentially elicit additional immune responses in vivo gene therapies if not removed by additional purification steps. Thus, there is a need to increase the genome packaging efficiency and reduce the number of empty capsids from AAV biologics. The novel Rep hybrids from different AAV serotypes described in this study are capable of reducing the percentage of empty capsids in all tested AAV serotypes and improve overall yields of genome-containing AAV capsids at the same time. They can likely be integrated easily into existing AAV manufacturing protocols to optimize the production of the generated AAV gene therapy products.
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Affiliation(s)
- Mario Mietzsch
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Courtnee Eddington
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Ariana Jose
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Jane Hsi
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Paul Chipman
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Tom Henley
- Intima Bioscience, New York, New York, USA
| | | | - Robert McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, Florida, USA
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Havlik LP, Simon KE, Smith JK, Klinc KA, Tse LV, Oh DK, Fanous MM, Meganck RM, Mietzsch M, Kleinschmidt J, Agbandje-McKenna M, Asokan A. Coevolution of Adeno-associated Virus Capsid Antigenicity and Tropism through a Structure-Guided Approach. J Virol 2020; 94:e00976-20. [PMID: 32669336 PMCID: PMC7495376 DOI: 10.1128/jvi.00976-20] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 07/06/2020] [Indexed: 12/26/2022] Open
Abstract
Adeno-associated viruses (AAV) are composed of nonenveloped, icosahedral protein shells that can be adapted to package and deliver recombinant therapeutic DNA. Approaches to engineer recombinant capsids for gene therapy applications have focused on rational design or library-based approaches that can address one or two desirable attributes; however, there is an unmet need to comprehensively improve AAV vector properties. Such cannot be achieved by utilizing sequence data alone but requires harnessing the three-dimensional (3D) structural properties of AAV capsids. Here, we solve the structures of a natural AAV isolate complexed with antibodies using cryo-electron microscopy and harness this structural information to engineer AAV capsid libraries through saturation mutagenesis of different antigenic footprints. Each surface loop was evolved by infectious cycling in the presence of a helper adenovirus to yield a new AAV variant that then serves as a template for evolving the next surface loop. This stepwise process yielded a humanized AAV8 capsid (AAVhum.8) displaying nonnatural surface loops that simultaneously display tropism for human hepatocytes, increased gene transfer efficiency, and neutralizing antibody evasion. Specifically, AAVhum.8 can better evade neutralizing antisera from multiple species than AAV8. Further, AAVhum.8 displays robust transduction in a human liver xenograft mouse model with expanded tropism for both murine and human hepatocytes. This work supports the hypothesis that critical properties, such as AAV capsid antibody evasion and tropism, can be coevolved by combining rational design and library-based evolution for clinical gene therapy.IMPORTANCE Clinical gene therapy with recombinant AAV vectors has largely relied on natural capsid isolates. There is an unmet need to comprehensively improve AAV tissue tropism, transduction efficiency, and antibody evasion. Such cannot be achieved by utilizing capsid sequence data alone but requires harnessing the 3D structural properties of AAV capsids. Here, we combine rational design and library-based evolution to coevolve multiple, desirable properties onto AAV by harnessing 3D structural information.
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Affiliation(s)
- L Patrick Havlik
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Katherine E Simon
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - J Kennon Smith
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Kelli A Klinc
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Longping V Tse
- School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
| | - Daniel K Oh
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Marco M Fanous
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Rita M Meganck
- Curriculum in Genetics and Molecular Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
| | - Mario Mietzsch
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Jürgen Kleinschmidt
- German Cancer Research Center, Research Program Infection and Cancer, Heidelberg, Germany
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, University of Florida, Gainesville, Florida, USA
| | - Aravind Asokan
- Department of Surgery, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, USA
- Regeneration Next, Duke University, Durham, North Carolina, USA
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24
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Mietzsch M, McKenna R, Väisänen E, Yu JC, Ilyas M, Hull JA, Kurian J, Smith JK, Chipman P, Lasanajak Y, Smith D, Söderlund-Venermo M, Agbandje-McKenna M. Structural Characterization of Cuta- and Tusavirus: Insight into Protoparvoviruses Capsid Morphology. Viruses 2020; 12:E653. [PMID: 32560452 PMCID: PMC7354515 DOI: 10.3390/v12060653] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2020] [Revised: 06/12/2020] [Accepted: 06/13/2020] [Indexed: 12/15/2022] Open
Abstract
Several members of the Protoparvovirus genus, capable of infecting humans, have been recently discovered, including cutavirus (CuV) and tusavirus (TuV). To begin the characterization of these viruses, we have used cryo-electron microscopy and image reconstruction to determine their capsid structures to ~2.9 Å resolution, and glycan array and cell-based assays to identify glycans utilized for cellular entry. Structural comparisons show that the CuV and TuV capsids share common features with other parvoviruses, including an eight-stranded anti-parallel β-barrel, depressions at the icosahedral 2-fold and surrounding the 5-fold axes, and a channel at the 5-fold axes. However, the viruses exhibit significant topological differences in their viral protein surface loops. These result in three separated 3-fold protrusions, similar to the bufaviruses also infecting humans, suggesting a host-driven structure evolution. The surface loops contain residues involved in receptor binding, cellular trafficking, and antigenic reactivity in other parvoviruses. In addition, terminal sialic acid was identified as the glycan potentially utilized by both CuV and TuV for cellular entry, with TuV showing additional recognition of poly-sialic acid and sialylated Lewis X (sLeXLeXLeX) motifs reported to be upregulated in neurotropic and cancer cells, respectively. These structures provide a platform for annotating the cellular interactions of these human pathogens.
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Affiliation(s)
- Mario Mietzsch
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Robert McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Elina Väisänen
- Department of Virology, University of Helsinki, 00014 Helsinki, Finland; (E.V.); (M.S.-V.)
| | - Jennifer C. Yu
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Maria Ilyas
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Joshua A. Hull
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Justin Kurian
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - J. Kennon Smith
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Paul Chipman
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
| | - Yi Lasanajak
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, GA 30322, USA; (Y.L.); (D.S.)
| | - David Smith
- Emory Comprehensive Glycomics Core, Emory University School of Medicine, Atlanta, GA 30322, USA; (Y.L.); (D.S.)
| | | | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, McKnight Brain Institute, College of Medicine, University of Florida, Gainesville, FL 32610, USA; (M.M.); (R.M.); (J.C.Y.); (M.I.); (J.A.H.); (J.K.); (J.K.S.); (P.C.)
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25
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Maurer AC, Weitzman MD. Adeno-Associated Virus Genome Interactions Important for Vector Production and Transduction. Hum Gene Ther 2020; 31:499-511. [PMID: 32303138 PMCID: PMC7232694 DOI: 10.1089/hum.2020.069] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022] Open
Abstract
Recombinant adeno-associated virus has emerged as one of the most promising gene therapy delivery vectors. Development of these vectors took advantage of key features of the wild-type adeno-associated virus (AAV), enabled by basic studies of the underlying biology and requirements for transcription, replication, and packaging of the viral genome. Each step in generating and utilizing viral vectors involves numerous molecular interactions that together determine the efficiency of vector production and gene delivery. Once delivered into the cell, interactions with host proteins will determine the fate of the viral genome, and these will impact the intended goal of gene delivery. Here, we provide an overview of known interactions of the AAV genome with viral and cellular proteins involved in its amplification, packaging, and expression. Further appreciation of how the AAV genome interacts with host factors will enhance how this simple virus can be harnessed for an array of vector purposes that benefit human health.
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Affiliation(s)
- Anna C. Maurer
- Department of Molecular and Cell Biology, University of California, Berkeley, California, USA
| | - Matthew D. Weitzman
- Division of Protective Immunity, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Division of Cancer Pathobiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
- Department of Pathology and Laboratory Medicine, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
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26
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Holographic Imaging of Insect Cell Cultures: Online Non-Invasive Monitoring of Adeno-Associated Virus Production and Cell Concentration. Processes (Basel) 2020. [DOI: 10.3390/pr8040487] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The insect cell-baculovirus vector system has become one of the favorite platforms for the expression of viral vectors for vaccination and gene therapy purposes. As it is a lytic system, it is essential to balance maximum recombinant product expression with harvest time, minimizing product exposure to detrimental proteases. With this purpose, new bioprocess monitoring solutions are needed to accurately estimate culture progression. Herein, we used online digital holographic microscopy (DHM) to monitor bioreactor cultures of Sf9 insect cells. Batches of baculovirus-infected Sf9 cells producing recombinant adeno-associated virus (AAV) and non-infected cells were used to evaluate DHM prediction capabilities for viable cell concentration, culture viability and AAV titer. Over 30 cell-related optical attributes were quantified using DHM, followed by a forward stepwise regression to select the most significant (p < 0.05) parameters for each variable. We then applied multiple linear regression to obtain models which were able to predict culture variables with root mean squared errors (RMSE) of 7 × 105 cells/mL, 3% for cell viability and 2 × 103 AAV/cell for 3-fold cross-validation. Overall, this work shows that DHM can be implemented for online monitoring of Sf9 concentration and viability, also permitting to monitor product titer, namely AAV, or culture progression in lytic systems, making it a valuable tool to support the time of harvest decision and for the establishment of controlled feeding strategies.
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27
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Mietzsch M, Pénzes JJ, Agbandje-McKenna M. Twenty-Five Years of Structural Parvovirology. Viruses 2019; 11:E362. [PMID: 31010002 PMCID: PMC6521121 DOI: 10.3390/v11040362] [Citation(s) in RCA: 101] [Impact Index Per Article: 20.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 04/10/2019] [Accepted: 04/11/2019] [Indexed: 12/13/2022] Open
Abstract
Parvoviruses, infecting vertebrates and invertebrates, are a family of single-stranded DNA viruses with small, non-enveloped capsids with T = 1 icosahedral symmetry. A quarter of a century after the first parvovirus capsid structure was published, approximately 100 additional structures have been analyzed. This first structure was that of Canine Parvovirus, and it initiated the practice of structure-to-function correlation for the family. Despite high diversity in the capsid viral protein (VP) sequence, the structural topologies of all parvoviral capsids are conserved. However, surface loops inserted between the core secondary structure elements vary in conformation that enables the assembly of unique capsid surface morphologies within individual genera. These variations enable each virus to establish host niches by allowing host receptor attachment, specific tissue tropism, and antigenic diversity. This review focuses on the diversity among the parvoviruses with respect to the transcriptional strategy of the encoded VPs, the advances in capsid structure-function annotation, and therapeutic developments facilitated by the available structures.
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Affiliation(s)
- Mario Mietzsch
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Judit J Pénzes
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
| | - Mavis Agbandje-McKenna
- Department of Biochemistry and Molecular Biology, Center for Structural Biology, The McKnight Brain Institute, University of Florida, Gainesville, FL 32610, USA.
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