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Nature Reviews. Genetics Apr 2020Adeno-associated virus (AAV) vector-mediated gene delivery was recently approved for the treatment of inherited blindness and spinal muscular atrophy, and long-term... (Review)
Review
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 muscular 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.
Topics: Adaptive Immunity; Dependovirus; Genetic Engineering; Genetic Therapy; Genetic Vectors; Immunity, Innate
PubMed: 32042148
DOI: 10.1038/s41576-019-0205-4 -
Cells Mar 2023Despite scientific discoveries in the field of gene and cell therapy, some diseases still have no effective treatment. Advances in genetic engineering methods have... (Review)
Review
Despite scientific discoveries in the field of gene and cell therapy, some diseases still have no effective treatment. Advances in genetic engineering methods have enabled the development of effective gene therapy methods for various diseases based on adeno-associated viruses (AAVs). Today, many AAV-based gene therapy medications are being investigated in preclinical and clinical trials, and new ones are appearing on the market. In this article, we present a review of AAV discovery, properties, different serotypes, and tropism, and a following detailed explanation of their uses in gene therapy for disease of different organs and systems.
Topics: Serogroup; Genetic Vectors; Genetic Therapy; Genetic Engineering; Tropism; Dependovirus
PubMed: 36899921
DOI: 10.3390/cells12050785 -
Nature Methods Aug 2022As the resident immune cells in the central nervous system (CNS), microglia orchestrate immune responses and dynamically sculpt neural circuits in the CNS. Microglial...
As the resident immune cells in the central nervous system (CNS), microglia orchestrate immune responses and dynamically sculpt neural circuits in the CNS. Microglial dysfunction and mutations of microglia-specific genes have been implicated in many diseases of the CNS. Developing effective and safe vehicles for transgene delivery into microglia will facilitate the studies of microglia biology and microglia-associated disease mechanisms. Here, we report the discovery of adeno-associated virus (AAV) variants that mediate efficient in vitro and in vivo microglial transduction via directed evolution of the AAV capsid protein. These AAV-cMG and AAV-MG variants are capable of delivering various genetic payloads into microglia with high efficiency, and enable sufficient transgene expression to support fluorescent labeling, Ca and neurotransmitter imaging and genome editing in microglia in vivo. Furthermore, single-cell RNA sequencing shows that the AAV-MG variants mediate in vivo transgene delivery without inducing microglia immune activation. These AAV variants should facilitate the use of various genetically encoded sensors and effectors in the study of microglia-related biology.
Topics: Dependovirus; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors; Microglia; Transduction, Genetic
PubMed: 35879607
DOI: 10.1038/s41592-022-01547-7 -
Trends in Molecular Medicine Mar 2022In vivo therapeutic gene transfer has emerged as a novel class of medicines. Its feasibility relies on the safe and efficacious delivery of genetic cargo to the... (Review)
Review
In vivo therapeutic gene transfer has emerged as a novel class of medicines. Its feasibility relies on the safe and efficacious delivery of genetic cargo to the appropriate targets. The adeno-associated virus (AAV) vector manifested itself as a preferred gene delivery vehicle enabling therapeutic gene expression for several clinical indications. Here, we cover the recent trends in AAV capsid engineering to enhance its targeting specificity, safety, and endurance. While each and every desirable trait can be individually remodeled, combining several attributes in one capsid amounts to a significant engineering challenge. Taking advantage of virion structure and phylogenetics, harnessing directed evolution, sequence analyses, and machine learning, researchers develop novel capsid variants to realize the goals of safe and enduring gene therapy.
Topics: Capsid; Capsid Proteins; Dependovirus; Genetic Therapy; Genetic Vectors; Humans; Transduction, Genetic
PubMed: 35093287
DOI: 10.1016/j.molmed.2022.01.003 -
Annual Review of Neuroscience Jul 2022Recombinant adeno-associated viruses (AAVs) are commonly used gene delivery vehicles for neuroscience research. They have two engineerable features: the capsid (outer... (Review)
Review
Recombinant adeno-associated viruses (AAVs) are commonly used gene delivery vehicles for neuroscience research. They have two engineerable features: the capsid (outer protein shell) and cargo (encapsulated genome). These features can be modified to enhance cell type or tissue tropism and control transgene expression, respectively. Several engineered AAV capsids with unique tropisms have been identified, including variants with enhanced central nervous system transduction, cell type specificity, and retrograde transport in neurons. Pairing these AAVs with modern gene regulatory elements and state-of-the-art reporter, sensor, and effector cargo enables highly specific transgene expression for anatomical and functional analyses of brain cells and circuits. Here, we discuss recent advances that provide a comprehensive (capsid and cargo) AAV toolkit for genetic access to molecularly defined brain cell types.
Topics: Brain; Capsid; Dependovirus; Gene Transfer Techniques; Genetic Vectors
PubMed: 35440143
DOI: 10.1146/annurev-neuro-111020-100834 -
Trends in Biotechnology Oct 2023Accelerating the scale up of adeno-associated virus (AAV) manufacture is highly desirable to meet the increased demand for gene therapies. However, the development of... (Review)
Review
Accelerating the scale up of adeno-associated virus (AAV) manufacture is highly desirable to meet the increased demand for gene therapies. However, the development of bioprocesses for AAV gene therapies remains time-consuming and challenging. The quality by design (QbD) approach ensures bioprocess designs that meet the desired product quality and safety profile. Rapid stress tests, developability screens, and scale-down technologies have the potential to streamline AAV product and manufacturing bioprocess development within the QbD framework. Here we review how their successful use for antibody manufacture development is translating to AAV, but also how this will depend critically on improved analytical methods and adaptation of the tools as more understanding is gained on the critical attributes of AAV required for successful therapy.
Topics: Dependovirus; Genetic Therapy; Commerce; Quality Control; Genetic Vectors
PubMed: 37127491
DOI: 10.1016/j.tibtech.2023.04.002 -
Nature Reviews. Drug Discovery Oct 2023Recent advancements in gene supplementation therapy are expanding the options for the treatment of neurological disorders. Among the available delivery vehicles,... (Review)
Review
Recent advancements in gene supplementation therapy are expanding the options for the treatment of neurological disorders. Among the available delivery vehicles, adeno-associated virus (AAV) is often the favoured vector. However, the results have been variable, with some trials dramatically altering the course of disease whereas others have shown negligible efficacy or even unforeseen toxicity. Unlike traditional drug development with small molecules, therapeutic profiles of AAV gene therapies are dependent on both the AAV capsid and the therapeutic transgene. In this rapidly evolving field, numerous clinical trials of gene supplementation for neurological disorders are ongoing. Knowledge is growing about factors that impact the translation of preclinical studies to humans, including the administration route, timing of treatment, immune responses and limitations of available model systems. The field is also developing potential solutions to mitigate adverse effects, including AAV capsid engineering and designs to regulate transgene expression. At the same time, preclinical research is addressing new frontiers of gene supplementation for neurological disorders, with a focus on mitochondrial and neurodevelopmental disorders. In this Review, we describe the current state of AAV-mediated neurological gene supplementation therapy, including critical factors for optimizing the safety and efficacy of treatments, as well as unmet needs in this field.
Topics: Humans; Dependovirus; Genetic Therapy; Transgenes; Models, Biological; Nervous System Diseases; Genetic Vectors
PubMed: 37658167
DOI: 10.1038/s41573-023-00766-7 -
Viruses Jun 2020The adeno-associated virus (AAV) is a small, nonpathogenic parvovirus, which depends on helper factors to replicate. Those helper factors can be provided by coinfecting... (Review)
Review
The adeno-associated virus (AAV) is a small, nonpathogenic parvovirus, which depends on helper factors to replicate. Those helper factors can be provided by coinfecting helper viruses such as adenoviruses, herpesviruses, or papillomaviruses. We review the basic biology of AAV and its most-studied helper viruses, adenovirus type 5 (AdV5) and herpes simplex virus type 1 (HSV-1). We further outline the direct and indirect interactions of AAV with those and additional helper viruses.
Topics: Adenoviridae; Coinfection; Dependovirus; Helper Viruses; Herpesvirus 1, Human; Humans; Parvoviridae Infections; Viral Proteins; Virus Replication
PubMed: 32575422
DOI: 10.3390/v12060662 -
Trends in Microbiology May 2022Adeno-associated virus (AAV) is the leading vector in emerging treatments of inherited diseases. Higher transduction efficiencies and cellular specificity are required... (Review)
Review
Adeno-associated virus (AAV) is the leading vector in emerging treatments of inherited diseases. Higher transduction efficiencies and cellular specificity are required for broader clinical application, motivating investigations of virus-host molecular interactions during cell entry. High-throughput methods are identifying host proteins more comprehensively, with subsequent molecular studies revealing unanticipated complexity and serotype specificity. Cryogenic electron microscopy (cryo-EM) provides a path towards structural details of these sometimes heterogeneous virus-host complexes, and is poised to illuminate more fully the steps in entry. Here presented, is progress in understanding the distinct steps of glycan attachment, and receptor-mediated entry/trafficking. Comparison with structures of antibody complexes provides new insights on immune neutralization with implications for the design of improved gene therapy vectors.
Topics: Dependovirus; Genetic Vectors; Polysaccharides; Receptors, Cell Surface; Serogroup; Virus Internalization
PubMed: 34711462
DOI: 10.1016/j.tim.2021.09.005 -
Journal of Pharmaceutical Sciences Jul 2021Adeno-associated virus (AAV) has emerged as a leading platform for gene delivery for treating various diseases due to its excellent safety profile and efficient... (Review)
Review
Adeno-associated virus (AAV) has emerged as a leading platform for gene delivery for treating various diseases due to its excellent safety profile and efficient transduction to various target tissues. However, the large-scale production and long-term storage of viral vectors is not efficient resulting in lower yields, moderate purity, and shorter shelf-life compared to recombinant protein therapeutics. This review provides a comprehensive analysis of upstream, downstream and formulation unit operation challenges encountered during AAV vector manufacturing, and discusses how desired product quality attributes can be maintained throughout product shelf-life by understanding the degradation mechanisms and formulation strategies. The mechanisms of various physical and chemical instabilities that the viral vector may encounter during its production and shelf-life because of various stressed conditions such as thermal, shear, freeze-thaw, and light exposure are highlighted. The role of buffer, pH, excipients, and impurities on the stability of viral vectors is also discussed. As such, the aim of this review is to outline the tools and a potential roadmap for improving the quality of AAV-based drug products by stressing the need for a mechanistic understanding of the involved processes.
Topics: Dependovirus; Gene Transfer Techniques; Genetic Therapy; Genetic Vectors
PubMed: 33812887
DOI: 10.1016/j.xphs.2021.03.024