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Current Protocols Jun 2024Adeno-associated virus (AAV) vectors can efficiently transduce exogenous genes into various tissues in vivo. Owing to their convenience, high efficiency, long-term...
Adeno-associated virus (AAV) vectors can efficiently transduce exogenous genes into various tissues in vivo. Owing to their convenience, high efficiency, long-term stable gene expression, and minimal side effects, AAV vectors have become one of the gold standards for investigating gene functions in vivo, especially in non-clinical studies. However, challenges persist in efficiently preparing a substantial quantity of high-quality AAV vectors. Commercial AAV vectors are typically associated with high costs. Further, in-laboratory production is hindered by the lack of specific laboratory equipment, such as ultracentrifuges. Therefore, a simple, quick, and scalable preparation method for AAV vectors is needed for proof-of-concept experiments. Herein, we present an optimized method for producing and purifying high-quality AAV serotype 9 (AAV9) vectors using standard laboratory equipment and chromatography. Using ceramic hydroxyapatite as a mixed-mode chromatography medium can markedly increase the quality of purified AAV vectors. Basic Protocols and optional methods for evaluating purified AAV vectors are also described. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Production of AAV9 vectors in 293EB cells Basic Protocol 2: Concentration and buffer exchange of AAV9 vectors from 293EB cell culture supernatants using tangential flow filtration Basic Protocol 3: Purification of AAV9 vectors from TFF samples using ceramic hydroxyapatite chromatography Basic Protocol 4: Analysis of the purified AAV9 vectors.
Topics: Dependovirus; Genetic Vectors; Humans; Ceramics; Serogroup; Durapatite; Chromatography; HEK293 Cells
PubMed: 38837274
DOI: 10.1002/cpz1.1068 -
ACS Nano Jun 2024Using viral vectors as gene delivery vehicles for gene therapy necessitates their quality control. Here, we report on nanopore sensing for nondestructively inspecting...
Using viral vectors as gene delivery vehicles for gene therapy necessitates their quality control. Here, we report on nanopore sensing for nondestructively inspecting genomes inside the nanoscale cargoes at the single-molecule level. Using ionic current measurements, we motion-tracked the adeno-associated virus (AAV) vectors as they translocated through a solid-state nanopore. Considering the varying contributions of the electrophoretic forces from the negatively charged internal polynucleotides of different lengths, the nanocargoes carrying longer DNA moved more slowly in the nanochannel. Moreover, ion blockage characteristics revealed their larger volume by up to approximately 3600 nm in proportion to the length of single-stranded DNA packaged inside, thereby allowing electrical discriminations of AAV vectors by the gene-derived physical features. The present findings can be a promising tool for the enhanced quality control of AAV products by enabling the screening of empty and intermediate vectors at the single-particle level.
Topics: Nanopores; Dependovirus; Genetic Vectors; DNA, Single-Stranded; Humans
PubMed: 38836590
DOI: 10.1021/acsnano.4c01888 -
Generation of nanobodies from transgenic 'LamaMice' lacking an endogenous immunoglobulin repertoire.Nature Communications Jun 2024Due to their exceptional solubility and stability, nanobodies have emerged as powerful building blocks for research tools and therapeutics. However, their generation in...
Due to their exceptional solubility and stability, nanobodies have emerged as powerful building blocks for research tools and therapeutics. However, their generation in llamas is cumbersome and costly. Here, by inserting an engineered llama immunoglobulin heavy chain (IgH) locus into IgH-deficient mice, we generate a transgenic mouse line, which we refer to as 'LamaMouse'. We demonstrate that LamaMice solely express llama IgH molecules without association to Igκ or λ light chains. Immunization of LamaMice with AAV8, the receptor-binding domain of the SARS-CoV-2 spike protein, IgE, IgG2c, and CLEC9A enabled us to readily select respective target-specific nanobodies using classical hybridoma and phage display technologies, single B cell screening, and direct cloning of the nanobody-repertoire into a mammalian expression vector. Our work shows that the LamaMouse represents a flexible and broadly applicable platform for a facilitated selection of target-specific nanobodies.
Topics: Animals; Single-Domain Antibodies; Camelids, New World; Immunoglobulin Heavy Chains; Mice, Transgenic; Mice; Spike Glycoprotein, Coronavirus; Lectins, C-Type; SARS-CoV-2; Immunoglobulin E; Humans; Dependovirus; Immunoglobulin G; COVID-19; B-Lymphocytes
PubMed: 38830864
DOI: 10.1038/s41467-024-48735-x -
Mutation Research. Genetic Toxicology... 2024Gene therapies have emerged as promising treatments for various conditions including inherited diseases as well as cancer. Ensuring their safe clinical application... (Review)
Review
Gene therapies have emerged as promising treatments for various conditions including inherited diseases as well as cancer. Ensuring their safe clinical application requires the development of appropriate safety testing strategies. Several guidelines have been provided by health authorities to address these concerns. These guidelines state that non-clinical testing should be carried out on a case-by-case basis depending on the modality. This review focuses on the genome safety assessment of frequently used gene therapy modalities, namely Adeno Associated Viruses (AAVs), Lentiviruses, designer nucleases and mRNAs. Important safety considerations for these modalities, amongst others, are vector integrations into the patient genome (insertional mutagenesis) and off-target editing. Taking into account the constraints of in vivo studies, health authorities endorse the development of novel approach methodologies (NAMs), which are innovative in vitro strategies for genotoxicity testing. This review provides an overview of NAMs applied to viral and CRISPR/Cas9 safety, including next generation sequencing-based methods for integration site analysis and off-target editing. Additionally, NAMs to evaluate the oncogenicity risk arising from unwanted genomic modifications are discussed. Thus, a range of promising techniques are available to support the safe development of gene therapies. Thorough validation, comparisons and correlations with clinical outcomes are essential to identify the most reliable safety testing strategies. By providing a comprehensive overview of these NAMs, this review aims to contribute to a better understanding of the genome safety perspectives of gene therapies.
Topics: Genetic Therapy; Humans; Gene Editing; Animals; Dependovirus; Genetic Vectors; CRISPR-Cas Systems; Lentivirus; Endonucleases; Mutagenicity Tests; Nucleotides
PubMed: 38821669
DOI: 10.1016/j.mrgentox.2024.503767 -
Medecine Sciences : M/S May 2024
Topics: Animals; Mice; Dependovirus; Deafness; Membrane Proteins; Genetic Vectors; Humans; Serine Endopeptidases; Genetic Therapy; Aging; Hearing; Disease Progression; Mice, Mutant Strains; Mutation; Neoplasm Proteins
PubMed: 38819271
DOI: 10.1051/medsci/2024042 -
PLoS Biology May 2024The CRISPR-associated endonuclease Cas12a has become a powerful genome-editing tool in biomedical research due to its ease of use and low off-targeting. However, the...
The CRISPR-associated endonuclease Cas12a has become a powerful genome-editing tool in biomedical research due to its ease of use and low off-targeting. However, the size of Cas12a severely limits clinical applications such as adeno-associated virus (AAV)-based gene therapy. Here, we characterized a novel compact Cas12a ortholog, termed EbCas12a, from the metagenome-assembled genome of a currently unclassified Erysipelotrichia. It has the PAM sequence of 5'-TTTV-3' (V = A, G, C) and the smallest size of approximately 3.47 kb among the Cas12a orthologs reported so far. In addition, enhanced EbCas12a (enEbCas12a) was also designed to have comparable editing efficiency with higher specificity to AsCas12a and LbCas12a in mammalian cells at multiple target sites. Based on the compact enEbCas12a, an all-in-one AAV delivery system with crRNA for Cas12a was developed for both in vitro and in vivo applications. Overall, the novel smallest high-fidelity enEbCas12a, this first case of the all-in-one AAV delivery for Cas12a could greatly boost future gene therapy and scientific research.
Topics: Dependovirus; Humans; Gene Editing; Genetic Vectors; CRISPR-Cas Systems; Animals; HEK293 Cells; Genetic Therapy; CRISPR-Associated Proteins; Mice; Endodeoxyribonucleases; Bacterial Proteins
PubMed: 38814985
DOI: 10.1371/journal.pbio.3002619 -
Turkish Journal of Medical Sciences 2023Dorsal root ganglia (DRG) are structures containing primary sensory neurons. Intraganglionic (IG) and intrathecal (IT) applications are the most common methods used for... (Comparative Study)
Comparative Study
BACKGROUND/AIM
Dorsal root ganglia (DRG) are structures containing primary sensory neurons. Intraganglionic (IG) and intrathecal (IT) applications are the most common methods used for viral vector transfer to DRG. We aim to compare the efficiencies and pathological effects of IT and IG viral vector delivery methods to DRG, through in vivo imaging.
MATERIALS AND METHODS
Mice were divided into four groups of six each: IT, IG, IT-vehicle, and IG-vehicle. Adeno-associated virus (AAV) injection was performed for EGFP expression in IT/IG groups. DRGs were made visible through vertebral window surgery and visualized with multiphoton microscopy. After imaging, spinal cords and DRGs were removed and cleared, then imaged with light sheet microscopy.
RESULTS
No neuronal death was observed after IT injection, while the death rate was 17% 24 h after IG injection. EGFP expression efficiencies were 90%-95% of neurons in both groups. EGFP expression was only observed in targeted L2 DRG after IG injection, while it was observed in DRGs located between L1-L5 levels after IT injection.
CONCLUSION
IT injection is a more suitable method for labeling DRG neurons in neurodegenerative injury models. However, when the innervation of DRG needs to be specifically studied, IT injection reduces this specificity due to its spread. In these studies, IG injection is the most suitable method for labeling single DRG neurons.
Topics: Animals; Ganglia, Spinal; Injections, Spinal; Mice; Dependovirus; Green Fluorescent Proteins; Genetic Vectors; Male
PubMed: 38813001
DOI: 10.55730/1300-0144.5702 -
International Journal of Molecular... May 2024Recombinant adeno-associated virus (rAAV) has emerged as a prominent vector for in vivo gene therapy, owing to its distinct advantages. Accurate determination of the...
Recombinant adeno-associated virus (rAAV) has emerged as a prominent vector for in vivo gene therapy, owing to its distinct advantages. Accurate determination of the rAAV genome titer is crucial for ensuring the safe and effective administration of clinical doses. The evolution of the rAAV genome titer assay from quantitative PCR (qPCR) to digital PCR (dPCR) has enhanced accuracy and precision, yet practical challenges persist. This study systematically investigated the impact of various operational factors on genome titration in a single-factor manner, aiming to address potential sources of variability in the quantitative determination process. Our findings revealed that a pretreatment procedure without genome extraction exhibits superior precision compared with titration with genome extraction. Additionally, notable variations in titration results across different brands of dPCR instruments were documented, with relative standard deviation (RSD) reaching 23.47% for AAV5 and 11.57% for AAV8. Notably, optimal operations about DNase I digestion were identified; we thought treatment time exceeding 30 min was necessary, and there was no need for thermal inactivation after digestion. And we highlighted that thermal capsid disruption before serial dilution substantially affected AAV genome titers, causing a greater than ten-fold decrease. Conversely, this study found that additive components of dilution buffer are not significant contributors to titration variations. Furthermore, we found that repeated freeze-thaw cycles significantly compromised AAV genome titers. In conclusion, a comprehensive dPCR titration protocol, incorporating insights from these impact factors, was proposed and successfully tested across multiple serotypes of AAV. The results demonstrate acceptable variations, with the RSD consistently below 5.00% for all tested AAV samples. This study provides valuable insights to reduce variability and improve the reproducibility of AAV genome titration using dPCR.
Topics: Dependovirus; Genome, Viral; Genetic Vectors; Humans; Polymerase Chain Reaction; HEK293 Cells; Genetic Therapy; Viral Load
PubMed: 38791184
DOI: 10.3390/ijms25105149 -
Current Gene Therapy 2024Osteoarthritis (OA) is a highly debilitating, degenerative pathology of cartilaginous joints affecting over 500 million people worldwide. The global economic burden of...
BACKGROUND
Osteoarthritis (OA) is a highly debilitating, degenerative pathology of cartilaginous joints affecting over 500 million people worldwide. The global economic burden of OA is estimated at $260-519 billion and growing, driven by aging global population and increasing rates of obesity. To date, only the multi-injection chondroanabolic treatment regimen of Fibroblast Growth Factor 18 (FGF18) has demonstrated clinically meaningful disease-modifying efficacy in placebo-controlled human trials. Our work focuses on the development of a novel single injection disease-modifying gene therapy, based on FGF18's chondroanabolic activity.
METHODS
OA was induced in Sprague-Dawley rats using destabilization of the medial meniscus (DMM) (3 weeks), followed by intra-articular treatment with 3 dose levels of AAV2-FGF18, rh- FGF18 protein, and PBS. Durability, redosability, and biodistribution were measured by quantifying nLuc reporter bioluminescence. Transcriptomic analysis was performed by RNA-seq on cultured human chondrocytes and rat knee joints. Morphological analysis was performed on knee joints stained with Safranin O/Fast Green and anti-PRG antibody.
RESULTS
Dose-dependent reductions in cartilage defect size were observed in the AAV2-FGF18- treated joints relative to the vehicle control. Total defect width was reduced by up to 76% and cartilage thickness in the thinnest zone was increased by up to 106%. Morphologically, the vehicle- treated joints exhibited pronounced degeneration, ranging from severe cartilage erosion and bone void formation, to subchondral bone remodeling and near-complete subchondral bone collapse. In contrast, AAV2-FGF18-treated joints appeared more anatomically normal, with only regional glycosaminoglycan loss and marginal cartilage erosion. While effective at reducing cartilage lesions, treatment with rhFGF18 injections resulted in significant joint swelling (19% increase in diameter), as well as a decrease in PRG4 staining uniformity and intensity. In contrast to early-timepoint RNA-seq analysis, which showed a high degree of concordance between protein- and gene therapy-treated chondrocytes, transcriptomic analysis, revealed few gene expression changes following protein treatment. On the other hand, the gene therapy treatment exhibited a high degree of durability and localization over the study period, upregulating several chondroanabolic genes while downregulating OA- and fibrocartilage-associated markers.
CONCLUSION
FGF18 gene therapy treatment of OA joints can provide benefits to both cartilage and subchondral bone, with a high degree of localization and durability.
Topics: Animals; Fibroblast Growth Factors; Genetic Therapy; Rats; Rats, Sprague-Dawley; Humans; Osteoarthritis; Disease Models, Animal; Cartilage, Articular; Dependovirus; Chondrocytes; Genetic Vectors; Male
PubMed: 38783531
DOI: 10.2174/0115665232275532231213063634 -
Genome Biology May 2024Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure. Multiple identified mutations in nexilin (NEXN) have been suggested to be linked with...
BACKGROUND
Dilated cardiomyopathy (DCM) is one of the most common causes of heart failure. Multiple identified mutations in nexilin (NEXN) have been suggested to be linked with severe DCM. However, the exact association between multiple mutations of Nexn and DCM remains unclear. Moreover, it is critical for the development of precise and effective therapeutics in treatments of DCM.
RESULTS
In our study, Nexn global knockout mice and mice carrying human equivalent G645del mutation are studied using functional gene rescue assays. AAV-mediated gene delivery is conducted through systemic intravenous injections at the neonatal stage. Heart tissues are analyzed by immunoblots, and functions are assessed by echocardiography. Here, we identify functional components of Nexilin and demonstrate that exogenous introduction could rescue the cardiac function and extend the lifespan of Nexn knockout mouse models. Similar therapeutic effects are also obtained in G645del mice, providing a promising intervention for future clinical therapeutics.
CONCLUSIONS
In summary, we demonstrated that a single injection of AAV-Nexn was capable to restore the functions of cardiomyocytes and extended the lifespan of Nexn knockout and G645del mice. Our study represented a long-term gene replacement therapy for DCM that potentially covers all forms of loss-of-function mutations in NEXN.
Topics: Animals; Cardiomyopathy, Dilated; Mice, Knockout; Mice; Genetic Therapy; Humans; Dependovirus; Myocytes, Cardiac; Disease Models, Animal; Mutation; Genetic Vectors; Gene Transfer Techniques
PubMed: 38783323
DOI: 10.1186/s13059-024-03283-x