1
|
Yuan Y, Higashiyama K, Hashiba N, Masumi-Koizumi K, Yusa K, Uchida K. Concise Analysis of Single-Stranded DNA of Recombinant Adeno-Associated Virus By Automated Electrophoresis System. Hum Gene Ther 2024; 35:104-113. [PMID: 38062752 PMCID: PMC10890949 DOI: 10.1089/hum.2023.148] [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: 08/22/2023] [Accepted: 11/29/2023] [Indexed: 02/01/2024] Open
Abstract
Recombinant adeno-associated virus (rAAV) is a prominent viral vector currently available for human gene therapy. The diameter of the rAAV capsid is ∼25 nm, and a positive or negative single-stranded DNA is packaged within the vector capsid. In this report, we describe a concise method to examine the extracted rAAV genome using an automated electrophoresis system. The rAAV genome, prepared from vector particles through either heat treatment at 95°C for 10 min or the phenol-chloroform extraction method, was analyzed using an automated electrophoresis system under denaturation conditions. The heat treatment protocol demonstrated a comparable yield with the phenol-chloroform extraction protocol, and the quantified amounts of the rAAV genome obtained using the automated electrophoresis system were consistent with those quantitated by quantitative PCR. Additionally, crude rAAV extractions could also be analyzed by the automated electrophoresis system after DNase I treatment. These results indicated that this simple and quick analysis using automated electrophoresis is highly useful for confirming the purity and integrity of the rAAV genome.
Collapse
Affiliation(s)
- Yuzhe Yuan
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| | - Kiyoko Higashiyama
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| | - Noriko Hashiba
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| | - Kyoko Masumi-Koizumi
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| | - Keisuke Yusa
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| | - Kazuhisa Uchida
- Graduate School of Science, Technology and Innovation, Kobe University, Chuo-ku, Kobe, Japan
| |
Collapse
|
2
|
Brimble MA, Winston SM, Davidoff AM. Stowaways in the cargo: Contaminating nucleic acids in rAAV preparations for gene therapy. Mol Ther 2023; 31:2826-2838. [PMID: 37533254 PMCID: PMC10556190 DOI: 10.1016/j.ymthe.2023.07.025] [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: 04/29/2023] [Revised: 07/11/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023] Open
Abstract
Recombinant AAV (rAAV) is the most used delivery vector for clinical gene therapy. However, many issues must be addressed before safer and more widespread implementation can be achieved. At present, efficacies are highly variable across trials and patients, and immune responses after treatment are widely reported. Although rAAV is capable of directly delivering gene-encoded therapeutic sequences, increased scrutiny of viral preparations for translational use have revealed contaminating nucleic acid species packaged within rAAV preparations. The introduction of non-therapeutic nucleic acids into a recipient patient adds to the risk burden, immunogenic or otherwise, of rAAV therapies. DNA from incomplete expression cassettes, portions of plasmids or vectors used to facilitate viral replication, and production cell line genomes all have the potential to be packaged within rAAV. Here, we review what is currently known about the profile, abundance, and post-treatment consequences of nucleic acid impurities within rAAV and cover strategies that have been developed to improve rAAV purity. Furthering our understanding of these aberrantly packaged DNA species will help to ensure the continued safe implementation of rAAV therapies as the number of patients treated with this modality increases.
Collapse
Affiliation(s)
- Mark A Brimble
- Department of Immunology, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA.
| | - Stephen M Winston
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA; St. Jude Children's Research Hospital Graduate School of Biomedical Sciences, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Andrew M Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| |
Collapse
|
3
|
Tran NT, Lecomte E, Saleun S, Namkung S, Robin C, Weber K, Devine E, Blouin V, Adjali O, Ayuso E, Gao G, Penaud-Budloo M, Tai PW. Human and Insect Cell-Produced Recombinant Adeno-Associated Viruses Show Differences in Genome Heterogeneity. Hum Gene Ther 2022; 33:371-388. [PMID: 35293222 PMCID: PMC9063199 DOI: 10.1089/hum.2022.050] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 03/02/2022] [Indexed: 02/01/2023] Open
Abstract
In the past two decades, adeno-associated virus (AAV) vector manufacturing has made remarkable advancements to meet large-scale production demands for preclinical and clinical trials. In addition, AAV vectors have been extensively studied for their safety and efficacy. In particular, the presence of empty AAV capsids and particles containing "inaccurate" vector genomes in preparations has been a subject of concern. Several methods exist to separate empty capsids from full particles; but thus far, no single technique can produce vectors that are free of empty or partial (non-unit length) capsids. Unfortunately, the exact genome compositions of full, intermediate, and empty capsids remain largely unknown. In this work, we used AAV-genome population sequencing to explore the compositions of DNase-resistant, encapsidated vector genomes produced by two common production pipelines: plasmid transfection in human embryonic kidney cells (pTx/HEK293) and baculovirus expression vectors in Spodoptera frugiperda insect cells (rBV/Sf9). Intriguingly, our results show that vectors originating from the same construct design that were manufactured by the rBV/Sf9 system produced a higher degree of truncated and unresolved species than those generated by pTx/HEK293 production. We also demonstrate that empty particles purified by cesium chloride gradient ultracentrifugation are not truly empty but are instead packaged with genomes composed of a single truncated and/or unresolved inverted terminal repeat (ITR). Our data suggest that the frequency of these "mutated" ITRs correlates with the abundance of inaccurate genomes in all fractions. These surprising findings shed new light on vector efficacy, safety, and how clinical vectors should be quantified and evaluated.
Collapse
Affiliation(s)
- Ngoc Tam Tran
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, Massachusetts, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Emilie Lecomte
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Sylvie Saleun
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Suk Namkung
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, Massachusetts, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, Massachusetts, USA
| | - Cécile Robin
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | | | - Eric Devine
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Veronique Blouin
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Oumeya Adjali
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Eduard Ayuso
- INSERM UMR 1089, University of Nantes, CHU of Nantes, Nantes, France
| | - Guangping Gao
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, Massachusetts, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, Massachusetts, USA
- Li Weibo Institute of Rare Diseases Research; UMass Chan Medical School, Worcester, Massachusetts, USA
| | | | - Phillip W.L. Tai
- Horae Gene Therapy Center, UMass Chan Medical School, Worcester, Massachusetts, USA
- Department of Microbiology and Physiological Systems, UMass Chan Medical School, Worcester, Massachusetts, USA
- Li Weibo Institute of Rare Diseases Research; UMass Chan Medical School, Worcester, Massachusetts, USA
| |
Collapse
|
4
|
Brimble MA, Cheng PH, Winston SM, Reeves IL, Souquette A, Spence Y, Zhou J, Wang YD, Morton CL, Valentine M, Thomas PG, Nathwani AC, Gray JT, Davidoff AM. Preventing packaging of translatable P5-associated DNA contaminants in recombinant AAV vector preps. Mol Ther Methods Clin Dev 2022; 24:280-291. [PMID: 35211640 PMCID: PMC8829444 DOI: 10.1016/j.omtm.2022.01.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Accepted: 01/16/2022] [Indexed: 11/25/2022]
Abstract
Recombinant adeno-associated virus (rAAV) vectors are increasingly being used for clinical gene transfer and have shown great potential for the treatment of several monogenic disorders. However, contaminant DNA from producer plasmids can be packaged into rAAV alongside the intended expression cassette-containing vector genome. The consequences of this are unknown. Our analysis of rAAV preps revealed abundant contaminant sequences upstream of the AAV replication (Rep) protein driving promoter, P5, on the Rep-Cap producer plasmid. Characterization of P5-associated contaminants after infection showed transfer, persistence, and transcriptional activity in AAV-transduced murine hepatocytes, in addition to in vitro evidence suggestive of integration. These contaminants can also be efficiently translated and immunogenic, revealing previously unrecognized side effects of rAAV-mediated gene transfer. P5-associated contaminant packaging and activity were independent of an inverted terminal repeat (ITR)-flanked vector genome. To prevent incorporation of these potentially harmful sequences, we constructed a modified P5-promoter (P5-HS), inserting a DNA spacer between an Rep binding site and an Rep nicking site in P5. This prevented upstream DNA contamination regardless of transgene or AAV serotype, while maintaining vector yield. Thus, we have constructed an rAAV production plasmid that improves vector purity and can be implemented across clinical rAAV applications. These findings represent new vector safety and production considerations for rAAV gene therapy.
Collapse
Affiliation(s)
- Mark A. Brimble
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Department of Haematology, University College London (UCL) Cancer Institute, London WC1E 6DD, UK
| | - Pei-Hsin Cheng
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Stephen M. Winston
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Isaiah L. Reeves
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Aisha Souquette
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Yunyu Spence
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Junfang Zhou
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Yong-Dong Wang
- Department of Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Christopher L. Morton
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
| | - Marcus Valentine
- Cytogenetics Shared Resource, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Paul G. Thomas
- Department of Immunology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Amit C. Nathwani
- Department of Haematology, University College London (UCL) Cancer Institute, London WC1E 6DD, UK
- Katharine Dormandy Haemophilia and Thrombosis Centre, Royal Free Hospital, London NW3 2QG, UK
| | - John T. Gray
- Vertex Cell and Genetic Therapies, Vertex Pharmaceuticals, Boston, MA 02210, USA
| | - Andrew M. Davidoff
- Department of Surgery, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, TN 38105, USA
- Graduate School of Biomedical Sciences, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| |
Collapse
|
5
|
PCR-Based Analytical Methods for Quantification and Quality Control of Recombinant Adeno-Associated Viral Vector Preparations. Pharmaceuticals (Basel) 2021; 15:ph15010023. [PMID: 35056080 PMCID: PMC8779925 DOI: 10.3390/ph15010023] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/17/2021] [Accepted: 12/22/2021] [Indexed: 11/17/2022] Open
Abstract
Recombinant adeno-associated viral vectors (rAAV) represent a gene therapy tool of ever-increasing importance. Their utilization as a delivery vehicle for gene replacement, silencing and editing, among other purposes, demonstrate considerable versatility. Emerging vector utilization in various experimental, preclinical and clinical applications establishes the necessity of producing and characterizing a wide variety of rAAV preparations. Critically important characteristics concerning quality control are rAAV titer quantification and the detection of impurities. Differences in rAAV constructs necessitate the development of highly standardized quantification assays to make direct comparisons of different preparations in terms of assembly or purification efficiency, as well as experimental or therapeutic dosages. The development of universal methods for impurities quantification is rather complicated, since variable production platforms are utilized for rAAV assembly. However, general agreements also should be achieved to address this issue. The majority of methods for rAAV quantification and quality control are based on PCR techniques. Despite the progress made, increasing evidence concerning high variability in titration assays indicates poor standardization of the methods undertaken to date. This review summarizes successes in the field of rAAV quality control and emphasizes ongoing challenges in PCR applications for rAAV characterization. General considerations regarding possible solutions are also provided.
Collapse
|
6
|
Green EA, Lee KH. Analytical methods to characterize recombinant adeno-associated virus vectors and the benefit of standardization and reference materials. Curr Opin Biotechnol 2021; 71:65-76. [PMID: 34273809 PMCID: PMC8530916 DOI: 10.1016/j.copbio.2021.06.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 05/26/2021] [Accepted: 06/28/2021] [Indexed: 12/18/2022]
Abstract
Recombinant adeno-associated virus (rAAV) is an increasingly important gene therapy vector, but its properties present unique challenges to critical quality attribute (CQA) identification and analytics development. Advances in, and ongoing hurdles to, characterizing rAAV proteins, nucleic acids, and vector potency are discussed in this review. For nucleic acids and vector potency, current analytical techniques for defined CQAs would benefit from further optimization, while for proteins, more complete characterization and mapping of properties to safety and efficacy is needed to finalize CQAs. The benefits of leveraging reference vectors to validate analytics and CQA ranges are also proposed. Once defined, CQA specifications can be used to establish target parameters for and inform the development of next generation rAAV processes.
Collapse
Affiliation(s)
- Erica A Green
- Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA
| | - Kelvin H Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, 590 Avenue 1743, Newark, DE 19713, USA.
| |
Collapse
|
7
|
Peixoto C, Merten O. Biomanufacturing of Gene Therapy Vectors. Biotechnol J 2021. [DOI: 10.1002/biot.202000614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Cristina Peixoto
- iBET Instituto de Biologia Experimental e Tecnológica Oeiras Portugal
| | | |
Collapse
|