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Viruses Jun 2021Gene therapy vectors derived from different viral species have become a fixture in biomedicine, both for direct therapeutic intervention and as tools to facilitate... (Review)
Review
Gene therapy vectors derived from different viral species have become a fixture in biomedicine, both for direct therapeutic intervention and as tools to facilitate cell-based therapies, such as chimeric antigen receptor-based immunotherapies. On the contrary, extracellular vesicles have only recently gained a massive increase in interest and, concomitantly, knowledge in the field has drastically risen. Viral infections and extracellular vesicle biology overlap in many ways, both with pro- and antiviral outcomes. In this review, we take a closer look at these interactions for the most prominent groups of viral vectors (Adenoviral, Adeno-associated and Retro/Lentiviral vectors) and the possible implications of these overlaps for viral vector technology and its biomedical applications.
Topics: Adenoviridae; Dependovirus; Extracellular Vesicles; Genetic Therapy; Genetic Vectors; Humans; Lentivirus; Retroviridae; Virus Diseases
PubMed: 34206771
DOI: 10.3390/v13071238 -
PloS One 2023Recombinant adeno-associated virus (rAAV) vectors have become a reliable strategy for delivering gene therapies. As rAAV capsid content is known to be heterogeneous,...
Recombinant adeno-associated virus (rAAV) vectors have become a reliable strategy for delivering gene therapies. As rAAV capsid content is known to be heterogeneous, methods for rAAV characterization are critical for assessing the efficacy and safety of drug products. Multiplex digital PCR (dPCR) has emerged as a popular molecular approach for characterizing capsid content due to its high level of throughput, accuracy, and replicability. Despite growing popularity, tools to accurately analyze multiplexed data are scarce. Here, we introduce a novel statistical model to estimate genome integrity from duplex dPCR assays. This work demonstrates that use of a Poisson-multinomial mixture distribution significantly improves the accuracy and quantifiable range of duplex dPCR assays over currently available models.
Topics: Genetic Vectors; Genetic Therapy; Transgenes; Polymerase Chain Reaction; Dependovirus
PubMed: 38096204
DOI: 10.1371/journal.pone.0293277 -
Current Gene Therapy Jun 2005In recent years, significant efforts have been made on studying and engineering adeno-associated virus (AAV) capsid, in order to increase efficiency in targeting... (Review)
Review
In recent years, significant efforts have been made on studying and engineering adeno-associated virus (AAV) capsid, in order to increase efficiency in targeting specific cell types that are non-permissive to wild type (wt) viruses and to improve efficacy in infecting only the cell type of interest. With our previous knowledge of the viral properties of the naturally occurring serotypes and the elucidation of their capsid structures, we can now generate capsid mutants, or hybrid serotypes, by various methods and strategies. In this review, we summarize the studies performed on AAV retargeting, and categorize the available hybrid serotypes to date, based on the type of modification: 1) transcapsidation, 2) adsorption of bi-specific antibody to capsid surface, 3) mosaic capsid, and 4) chimeric capsid. Not only these hybrid serotypes could achieve high efficiency of gene delivery to a specific targeted cell type, which can be better-tailored for a particular clinical application, but also serve as a tool for studying AAV biology such as receptor binding, trafficking and genome delivery into the nucleus.
Topics: Animals; Capsid Proteins; Dependovirus; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Humans; Recombination, Genetic; Serotyping
PubMed: 15975007
DOI: 10.2174/1566523054064968 -
Journal of Pharmaceutical and... Sep 2023After more than two decades of research and development, adeno-associated virus (AAV) has become one of the dominant delivery vectors in gene therapy. Despite the...
After more than two decades of research and development, adeno-associated virus (AAV) has become one of the dominant delivery vectors in gene therapy. Despite the focused research, the cell entry pathway for AAV is still not fully understood. Universal AAV receptor (AAVR) has been identified to be involved in cellular entry of different AAV serotypes. With the unveiling of the high-resolution AAV-AAVR complex structure by cryogenic electron microscopy, the atomic level interaction between AAV and AAVR has become the focus of study in recent years. However, the serotype dependence of this binding interaction and the effect of pH have not been studied. Here, orthogonal approaches including bio-layer interferometry (BLI), size-exclusion chromatography coupled to multi-angle laser scattering (SEC-MALS) and sedimentation velocity analytical ultracentrifugation (SV-AUC) were utilized to study the interaction between selected AAV serotypes and AAVR under different pH conditions. A robust BLI method was developed and the equilibrium dissociation binding constants (K) between different AAV serotypes (AAV1, AAV5 and AAV8) and AAVR was measured. The binding constants measured by BLI together with orthogonal methods (SEC-MALS and SV-AUC) all confirmed that AAV5 has the strongest binding affinity followed by AAV1 while AAV8 binds the weakest. It was also observed that lower pH promotes the binding between AAV and AAVR and neutral or slightly basic conditions lead to very weak binding. These data indicate that for certain serotypes, AAVR may play a prominent role in trafficking AAV to the Golgi rather than acting as a host cell receptor. Information obtained from these combinatorial biophysical methods can be used to engineer future generations of AAVs to have better transduction efficiency.
Topics: Dependovirus; Hydrogen-Ion Concentration; Protein Binding; Serogroup
PubMed: 37441888
DOI: 10.1016/j.jpba.2023.115562 -
Journal of Nippon Medical School =... 2012A variety of gene transfer strategies have been developed to treat inherited, degenerative, and acquired diseases. Among the different vector systems developed so far,... (Review)
Review
A variety of gene transfer strategies have been developed to treat inherited, degenerative, and acquired diseases. Among the different vector systems developed so far, recombinant adeno-associated viral (AAV) vectors have shown notable benefits, including prolonged gene expression, transduction of both dividing and nondividing cells, and a lack of pathogenicity caused by wild-type infections. Thanks to these features, the use of AAV vectors as a gene transfer tool has increased dramatically during the past several years, and several recent clinical trials have used AAV vectors. However, AAV vectors are more complicated to produce than are other viral vectors. With steady advances toward clinical application, much effort has been made to isolate novel AAV serotypes and to develop methods for their efficient, scalable, and versatile production and purification. Here we review state of the art methods for AAV vector production and purification, which we have refined in our laboratory.
Topics: Animals; Dependovirus; Genetic Vectors; Green Fluorescent Proteins; Mice; Mice, Inbred C57BL; Recombinant Fusion Proteins; Reproducibility of Results; Serotyping; Transduction, Genetic
PubMed: 23291836
DOI: 10.1272/jnms.79.394 -
Human Gene Therapy Feb 2017Within the next decade, we will see many gene therapy clinical trials for eye diseases, which may lead to treatments for thousands of visually impaired people around the... (Review)
Review
Within the next decade, we will see many gene therapy clinical trials for eye diseases, which may lead to treatments for thousands of visually impaired people around the world. To target retinal diseases that affect specific cell types, several recombinant adeno-associated virus (AAV) serotypes have been generated and used successfully in preclinical mouse studies. Because there are numerous anatomic and physiologic differences between the eyes of mice and "men" and because surgical delivery approaches and immunologic responses also differ between these species, this study evaluated the transduction characteristics of two promising new serotypes, AAV7m8 and AAV8BP2, in the retinas of animals that are most similar to those of humans: non-human primates (NHPs). We report that while AAV7m8 efficiently targets a variety of cell types by subretinal injection in NHPs, transduction after intravitreal delivery was mostly restricted to the inner retina at lower doses that did not induce an immune response. AAV8BP2 targets the cone photoreceptors efficiently but bipolar cells inefficiently by subretinal injection. Additionally, transduction by both serotypes in the anterior chamber of the eye and the optic pathway of the brain was observed post-intravitreal delivery. Finally, we assessed immunogenicity, keeping in mind that these AAV capsids may be used in future clinical trials. We found that AAV8BP2 had a better safety profile compared with AAV7m8, even at the highest doses administered. These studies underscore the differences in AAV transduction between mice and primates, highlighting the importance of careful evaluation of therapeutic vectors in NHPs prior to moving to clinical trials.
Topics: Animals; Dependovirus; Genetic Therapy; Genetic Vectors; Humans; Primates; Retina; Retinal Degeneration
PubMed: 27750461
DOI: 10.1089/hum.2016.111 -
Proceedings of the National Academy of... Oct 1996Adeno-associated virus (AAV) has attracted considerable interest as a potential vector for gene delivery. Wild-type virus is notable for the lack of association with any... (Review)
Review
Adeno-associated virus (AAV) has attracted considerable interest as a potential vector for gene delivery. Wild-type virus is notable for the lack of association with any human disease and the ability to stably integrate its genome in a site-specific manner in a locus on human chromosome 19 (AAVS1). Use of a functional model system for AAV DNA integration into AAVS1 has allowed us to conclude that the recombination event is directed by cellular DNA sequences. Recombinant junctions isolated from our integration assay were analyzed and showed characteristics similar to those found in latently infected cell lines. The minimal DNA signals within AAVS1 required for targeted integration were identified and shown to contain functional motifs of the viral origin of replication. A replication mediated model of AAV DNA integration is proposed.
Topics: Base Sequence; Chromosomes, Human, Pair 19; DNA; DNA Replication; DNA, Viral; Dependovirus; Genetic Vectors; Humans; Models, Genetic; Molecular Sequence Data; Nucleic Acid Conformation; Recombination, Genetic; Virus Integration; Virus Replication
PubMed: 8876128
DOI: 10.1073/pnas.93.21.11288 -
Clinical Microbiology Reviews Oct 2008The unique life cycle of adeno-associated virus (AAV) and its ability to infect both nondividing and dividing cells with persistent expression have made it an attractive... (Review)
Review
The unique life cycle of adeno-associated virus (AAV) and its ability to infect both nondividing and dividing cells with persistent expression have made it an attractive vector. An additional attractive feature of the wild-type virus is the lack of apparent pathogenicity. Gene transfer studies using AAV have shown significant progress at the level of animal models; clinical trials have been noteworthy with respect to the safety of AAV vectors. No proven efficacy has been observed, although in some instances, there have been promising observations. In this review, topics in AAV biology are supplemented with a section on AAV clinical trials with emphasis on the need for a deeper understanding of AAV biology and the development of efficient AAV vectors. In addition, several novel approaches and recent findings that promise to expand AAV's utility are discussed, especially in the context of combining gene therapy ex vivo with new advances in stem or progenitor cell biology.
Topics: Animals; Dependovirus; Genetic Therapy; Humans; Transduction, Genetic
PubMed: 18854481
DOI: 10.1128/CMR.00008-08 -
EMBO Molecular Medicine Apr 2023Over the last two decades, gene therapy has given hope of potential cure for many rare diseases. In the simplest form, gene therapy is the transfer or editing of a...
Over the last two decades, gene therapy has given hope of potential cure for many rare diseases. In the simplest form, gene therapy is the transfer or editing of a genetic material to cure a disease via nonviral or viral vehicles. Gene therapy can be performed either in vivo by injecting a vector carrying the gene or tools for gene editing directly into a tissue or into the systemic circulation, or ex vivo when patient cells are genetically modified outside of the body and then introduced back into the patient (Yilmaz et al, 2022). Adeno-associated viral vectors (AAV) have been the vectors of choice for in vivo gene therapy. There has been a lot of promising research on the development of novel tissue and cell-specific serotypes in order to improve efficacy and safety for clinical applications (Kuzmin et al, 2021). In this issue of EMBO Molecular Medicine, Boffa and colleagues present a novel AAV-based liver-directed gene therapy for ornithine aminotransferase deficiency.
Topics: Humans; Genetic Vectors; Liver; Genetic Therapy; Dependovirus
PubMed: 36846970
DOI: 10.15252/emmm.202217285 -
Frontiers in Immunology 2021Adeno-associated virus (AAV)-mediated gene transfer has benefited patients with inherited diseases, such as hemophilia B, by achieving long-term expression of the... (Review)
Review
Adeno-associated virus (AAV)-mediated gene transfer has benefited patients with inherited diseases, such as hemophilia B, by achieving long-term expression of the therapeutic transgene. Nevertheless, challenges remain due to rejection of AAV-transduced cells, which in some, but not all, patients can be prevented by immunosuppression. It is assumed that CD8 T cells induced by natural infections with AAVs are recalled by the AAV vector's capsid and upon activation eliminate cells expressing the degraded capsid antigens. Alternatively, it is feasible that AAV vectors, especially if given at high doses, induce capsid- or transgene product-specific T cell responses. This chapter discusses CD8 T cell responses to AAV infections and AAV gene transfer and avenues to prevent their activation or block their effector functions.
Topics: Animals; CD8-Positive T-Lymphocytes; Capsid Proteins; Dependovirus; Gene Transfer Techniques; Genetic Vectors; Humans; Immunosuppression Therapy; Models, Animal
PubMed: 33927727
DOI: 10.3389/fimmu.2021.666666