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John A. Chiorini – One of the best experts on this subject based on the ideXlab platform.
Human gene therapy, 2020Co-Authors: Maria C. Guimaro, Sandra Afione, Tsutomu Tanaka, John A. ChioriniAbstract:
Adeno-Associated Virus (AAV) vector technology is rapidly advancing and becoming not only the leading vector platform in the field of gene therapy but also a useful tool for functional genomic stud…
Adeno-Associated Virus type 4 (AAV4) targets ependyma and astrocytes in the subventricular zone and RMSGene Therapy, 2005Co-Authors: Gumei Liu, Inês Martins, John A. Chiorini, Beverly L. DavidsonAbstract:
Adeno-Associated Virus type 4 (AAV4) targets ependyma and astrocytes in the subventricular zone and RMS
Journal of virology, 2005Co-Authors: Eric Padron, Lakshmanan Govindasamy, John A. Chiorini, Valorie D. Bowman, Nikola Kaludov, Hazel C. Levy, Phillip Nick, Robert Mckenna, Nicholas Muzyczka, Timothy S. BakerAbstract:
Adeno-Associated Virus (AAV) is a member of the Parvoviridae, belonging to the DependoVirus genus. Currently, several distinct isolates of AAV are in development for use in human gene therapy applications due to their ability to transduce different target cells. The need to manipulate AAV capsids for specific tissue delivery has generated interest in understanding their capsid structures. The structure of AAV type 4 (AAV4), one of the most antigenically distinct serotypes, was determined to 13-A resolution by cryo-electron microscopy and image reconstruction. A pseudoatomic model was built for the AAV4 capsid by use of a structure-based sequence alignment of its major capsid protprotein, VP3, with that of AAV2, to which AAV4 is 58% identical and constrained by its reconstructed density envelope. The model showed variations in the surface loops that may account for the differences in receptor binding and antigenicity between AAV2 and AAV4. The AAV4 capsid surface topology also shows an unpredicted structural similarity to that of Aleutian mink disease Virus and human parvoVirus B19, autonomous members of the genus, despite limited sequence homology.
David W. Russell – One of the best experts on this subject based on the ideXlab platform.
Nature genetics, 2015Co-Authors: David W. Russell, Markus GrompeAbstract:
Adeno-Associated Virus (AAV) vectors have been widely adopted for use in gene therapy. A new study raises concerns regarding this approach, reporting that chromosomal insertions of AAV serotype 2 seem to activate proto-oncogenes in human hepatocellular carcinoma.
Current opinion in molecular therapeutics, 2009Co-Authors: David R. Deyle, David W. RussellAbstract:
Adeno-Associated Virus (AAV) vectors efficiently transduce various cell types and can produce long-term expression of transgenes in vivo. Although AAV vector genomes can persist within cells as episomes, vector integration has been observed in various experimental settings, either at non-homologous sites where DNA damage may have occurred or by homologous recombination. In some cases, integration is essential for the therapeutic or experimental efficacy of AAV vectors. Recently, insertional mutamutagenesis resulting from the integration of AAV vectors was associated with tumorigenesis in mice, a consideration that may have relevance for certain clinical applications.
Nature genetics, 2002Co-Authors: Daniel G. Miller, Elizabeth A. Rutledge, David W. RussellAbstract:
Adeno-Associated Virus (AAV) vectors are currently being used in several clinical gene-therapy trials (see the NIH OBA Human Gene Transfer Clinical Trials Database); however, little is known about the chromosomal effects of vector integration. Here we report that integrated vector proViruses are associated with chromosomal deletions and other rearrangements and are frequently located on chromosome 19 (although not at the wildtype AAV integration site).
James M Wilson – One of the best experts on this subject based on the ideXlab platform.
deamidation of amino acids on the surface of adeno associated Virus capsids leads to charge heterogeneity and altered vector functionMolecular Therapy, 2018Co-Authors: April R Giles, Joshua J Sims, Kevin B Turner, Lakshmanan Govindasamy, Mauricio R Alvira, Martin Lock, James M WilsonAbstract:
Post-translational modification of the Adeno-Associated Virus capsids is a poorly understood factor in the development of these viral vectors into pharmaceutical products. Here we report the extensive capsid deamidation of Adeno-Associated Virus serotype 8 and seven other diverse Adeno-Associated Virus serotypes, with supporting evidence from structural, biochemical, and mass spectrometry approaches. The extent of deamidation at each site depended on the vector’s age and multiple primary-sequence and three-dimensional structural factors. However, the extent of deamidation was largely independent of the vector recovery and purification conditions. We demonstrate the potential for deamidation to impact transduction activity and, moreover, correlate an early time point loss in vector activity to rapidly progressing spontaneous deamidation at several Adeno-Associated Virus 8 asparagines. We explore mutational strategies that stabilize side-chain amides, improving vector transduction and reducing the lot-to-lot molecular variability that presents a key concern in biologics manufacturing. This study illuminates a previously unknown aspect of Adeno-Associated Virus capsid heterogeneity and highlights its importance in the development of these vectors for gene therapy.
AdenoVirus–Adeno-Associated Virus Hybrid for Large-Scale Recombinant Adeno-Associated Virus ProductionHuman Gene Therapy, 2009Co-Authors: Hongwei Zhang, James M WilsonAbstract:
Abstract Recombinant Adeno-Associated Virus (rAAV) holds promise for applications in gene therapy. Advances in clinical studies of rAAV-based gene therapeutics have generated an encouraging momentum in the field of gene therapy; however, one of the major obstacles to the eventual clinical success of rAAV-mediated gene therapy is the need for large-scale production of clinical-grade vectors. The transfection-based rAAV production method is well suited for preclinical studies in small animal models, but it is difficult to support large-scale clinical studies with this method. In the past decade, several scalable rAAV production methods have emerged from extensive efforts to develop large-scale manufacturing processes. Among those, the recombinant adenoVirus–AAV infection method has some unique features in vector quality and yield. This minireview provides an overview of this scaleable rAAV production platform, describing its basic components and biological mechanisms and process.
Gene therapy, 1999Co-Authors: Narendra Chirmule, Kathleen J. Propert, Susan Magosin, Y Qian, Ruth Qian, James M WilsonAbstract:
Vectors based on human adenoVirus (Ad) and Adeno-Associated Virus (AAV) are being evaluated for human gene therapy. The response of the host to the vector, in terms of antigen-specific immunity, will play a substantial role in clinical outcome. We have surveyed cohorts of normal subjects and cystic fibrfibrosis patients for pre-existing immunity to these Viruses, caused by naturally acquired infections. A number of humoral and cellular assays to adenoVirus serotype 5 (Ad5) and Adeno-Associated Virus serotype 2 (AAV2) were performed from serum and peripheral blood mononuclear cells. Virtually all subjects had Ig to Ad5 although only 55% of these antibodies neutralized Virus (NAB). Approximately two of three patients demonstrated CD4+ T cells that proliferated to Ad antigens of which most were of the TH1 subset, based on cytokine secretion. A substantially different pattern of immune responses was observed to AAV2. Although virtually all patients had Ig to AAV2, most of these antibodies were not neutralizing (32% NAB) and only 5% of patients had peripheral blood lymphocytes that proliferated in response to AAV2 antigens. These studies demonstrate marked heterogeneity in pre-existing immunity to Ad5 and AAV2 in human populations. The impact of these findings on outcome following gene therapy will require further study.
Richard J. Samulski – One of the best experts on this subject based on the ideXlab platform.
Nature Reviews Genetics, 2020Co-Authors: Richard J. SamulskiAbstract:
Adeno-Associated Virus (AAV) vector-mediated gene delivery was recently approved for the treatment of inherited blindness and spinal muscular atrophy, and long-term therapeutic effects have been achieved for other rare diseases, including haemophilia and Duchenne muscmuscular dystrophy. However, current research indicates that the genetic modification of AAV vectors may further facilitate the success of AAV gene therapy. Vector engineering can increase AAV transduction efficiency (by optimizing the transgene cassette), vector tropism (using capsid engineering) and the ability of the capsid and transgene to avoid the host immune response (by genetically modifying these components), as well as optimize the large-scale production of AAV. Adeno-Associated Virus (AAV) vector-mediated gene delivery has had long-term therapeutic effects for several diseases, including haemophilia and Duchenne muscmuscular dystrophy. Genetically modifying AAV vectors to increase their transduction efficiency, vector tropism and ability to avoid the host immune response may further increase the success of AAV gene therapy.
Methods in molecular medicine, 1997Co-Authors: Jeffrey S. Bartlett, Richard J. SamulskiAbstract:
The development of gene transfer vectors from the human parvoVirus, Adeno-Associated Virus (AAV), has provided scientists with an efficient and effective way of delivering genes into mammalian cells. This chapter aims to explore the various practical aspects of the AAV vector system, and in consequence, to highlight particular difficulties that may be encountered by workers new to the field. However, before describing the methodology involved in the generation of recombinant AAV vectors, it is of value to briefly discuss the structure and life cycle of this unique Virus. Detailed and more extensive reviews that describe the biology of Adeno-Associated Virus are also available (1-3).
Viral Gene Techniques, 1995Co-Authors: A. W. Skulimowski, Richard J. SamulskiAbstract:
Publisher Summary This chapter describes the generation of a recombinant Adeno-Associated Virus (rAAV) that expresses the Escherichia coli β-galactosidase ( lac Z) gene and its use in identifying cell types permissive to AAV infection. Viral research has revealed a number of Viruses that can be modified to introduce novel genes efficiently into a variety of cell types, including adenoVirus, retroVirus, vaccinia Virus, herpesVirus, and Adeno-Associated Virus (AAV). Some of the unique features that make this Virus attractive for gene therapy include the facts that AAV is prevalent in humans, it has never been identified as a causative agent of human disease, and it is able to insert its genome locus-specifically into human chromosomes. AAVs are members of the family Parvoviridiae in the genus dependoVirus , appropriately named for their complete dependence on coinfection with a helper Virus for productive infection. In the absence of helper Virus, the wild-type ( wt ) AAV genome integrates efficiently in a locus-specific manner into the cellular genome and can exist as a proVirus for many cellular generations until rescue with a helper Virus. AAVs are among the smallest DNA animal Viruses. The production of recombinant lacZ AAV involves cotransfection of the AAV vector and helper plasmids into permissive cells, followed by adenoVirus infection.
Matthew D. Weitzman – One of the best experts on this subject based on the ideXlab platform.
Human gene therapy, 2020Co-Authors: Anna C. Maurer, Matthew D. WeitzmanAbstract:
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.
Methods in molecular biology (Clifton N.J.), 2011Co-Authors: Matthew D. Weitzman, R. Michael LindenAbstract:
Adeno-Associated Virus (AAV) was first discovered as a contaminant of adenoVirus stocks in the 1960s. The development of recombinant AAV vectors (rAAV) was facilitated by early studies that generated infectious molecular clones, determined the sequence of the genome, and defined the genetic elements of the Virus. The refinement of methods and protocols for the production and application of rAAV vectors has come from years of studies that explored the basic biology of this Virus and its interaction with host cells. Interest in improving vector performance has in turn driven studies that have provided tremendous insights into the basic biology of the AAV lifecycle. In this chapter, we review the background on AAV biology and its exploitation for vectors and gene delivery.
transduction with recombinant adeno associated Virus for gene therapy is limited by leading strand synthesisJournal of Virology, 1996Co-Authors: Krishna J Fisher, Matthew D. Weitzman, Guangping Gao, R Dematteo, John F Burda, James M WilsonAbstract:
Adeno-Associated Virus is an integrating DNA parvoVirus with the potential to be an important vehicle for somatic gene therapy. A potential barrier, however, is the low transduction efficiencies of recombinant Adeno-Associated Virus (rAAV) vectors. We show in this report that adenoVirus dramatically enhances rAAV transduction in vitro in a way that is dependent on expression of early region 1 and 4 (E1 and E4, respectively) genes and directly proportional to the appearance of double-stranded replicative forms of the rAAV genome. Expression of the open reading frame 6 protein from E4 in the absence of E1 accomplished a similar but attenuated effect. The helper activity of adenoVirus E1 and E4 for rAAV gene transfer was similarly demonstrated in vivo by using murine models of liver- and lung-directed gene therapy. Our data indicate that conversion of a single-stranded rAAV genome to a duplex intermediate limits transduction and usefulness for gene therapy.