Publications by authors named "James Miskin"

A wealth of high-throughput biological data, of which omics constitute a significant fraction, has been made publicly available in repositories over the past decades. These data come in various formats and cover a range of species and research areas providing insights into the complexities of biological systems; the public repositories hosting these data serve as multifaceted resources. The potentially greater value of these data lies in their secondary utilization as the deployment of data science and artificial intelligence in biology advances.

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Lentiviral vectors are highly efficient gene delivery vehicles used extensively in the rapidly growing field of cell and gene therapy. Demand for efficient, large-scale, lentiviral vector bioprocessing is growing as more therapies reach late-stage clinical trials and are commercialized. However, despite substantial progress, several process inefficiencies remain.

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Both cell surface and soluble extracellular glycosaminoglycans have been shown to interfere with the exogenous nucleic acid delivery efficiency of non-viral gene delivery, including lipoplex and polyplex-mediated transfection. Most gene therapy viral vectors used commercially and in clinical trials are currently manufactured using transient transfection-based bioprocesses. The growing demand for viral vector products, coupled with a global shortage in production capability, requires improved transfection technologies and processes to maximise process efficiency and productivity.

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Article Synopsis
  • The demand for Lentiviral Vector (LV) drug substances is rising, but manufacturing challenges persist, especially in primary capture using anion-exchange chromatography due to complex adsorption behaviors.
  • Understanding the structural components of LVs, particularly the envelope components, is crucial for effective process design, as high binding heterogeneity influences elution profiles.
  • Eliminating the VSV-G protein did not affect the two-peak elution profile, while targeting glycosaminoglycans (GAGs) significantly altered the distribution of LVs in these peaks, indicating different binding interactions within discrete LV populations.
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Large-scale transient transfection has advanced significantly over the last 20 years, enabling the effective production of a diverse range of biopharmaceutical products, including viral vectors. However, a number of challenges specifically related to transfection reagent stability and transfection complex preparation times remain. New developments and improved transfection technologies are required to ensure that transient gene expression-based bioprocesses can meet the growing demand for viral vectors.

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Use of lentiviral vectors (LVs) in clinical Cell and Gene Therapy applications is growing. However, functional product loss during capture chromatography, typically anion-exchange (AIEX), remains a significant unresolved challenge for the design of economic processes. Despite AIEX's extensive use, variable performance and generally low recovery is reported.

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Process analytical technology (PAT) has demonstrated huge potential to enable the development of improved biopharmaceutical manufacturing processes by ensuring the reliable provision of quality products. However, the complexities associated with the manufacture of advanced therapy medicinal products have resulted in a slow adoption of PAT tools into industrial bioprocessing operations, particularly in the manufacture of cell and gene therapy products. Here we describe the applicability of a novel refractometry-based PAT system (Ranger system), which was used to monitor the metabolic activity of HEK293T cell cultures during lentiviral vector (LVV) production processes in real time.

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Immunotherapy using chimeric antigen receptor-modified T cells has demonstrated high response rates in patients with B cell malignancies, and chimeric antigen receptor T cell therapy is now being investigated in several hematologic and solid tumor types. Chimeric antigen receptor T cells are generated by removing T cells from a patient's blood and engineering the cells to express the chimeric antigen receptor, which reprograms the T cells to target tumor cells. As chimeric antigen receptor T cell therapy moves into later-phase clinical trials and becomes an option for more patients, compliance of the chimeric antigen receptor T cell manufacturing process with global regulatory requirements becomes a topic for extensive discussion.

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It is a current regulatory requirement to demonstrate absence of detectable replication-competent lentivirus (RCL) in lentiviral vector products prior to use in clinical trials. Immune Design previously described an HIV-1-based integration-deficient lentiviral vector for use in cancer immunotherapy (VP02). VP02 is enveloped with E1001, a modified Sindbis virus glycoprotein which targets dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN) expressed on dendritic cells in vivo.

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Usher syndrome type 1B is a combined deaf-blindness condition caused by mutations in the MYO7A gene. Loss of functional myosin VIIa in the retinal pigment epithelia (RPE) and/or photoreceptors leads to blindness. We evaluated the impact of subretinally delivered UshStat, a recombinant EIAV-based lentiviral vector expressing human MYO7A, on photoreceptor function in the shaker1 mouse model for Usher type 1B that lacks a functional Myo7A gene.

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Background: Parkinson's disease is typically treated with oral dopamine replacement therapies; however, long-term treatment leads to motor complications and, occasionally, impulse control disorders caused by intermittent stimulation of dopamine receptors and off-target effects, respectively. We aimed to assess the safety, tolerability, and efficacy of bilateral, intrastriatal delivery of ProSavin, a lentiviral vector-based gene therapy aimed at restoring local and continuous dopamine production in patients with advanced Parkinson's disease.

Methods: We undertook a phase 1/2 open-label trial with 12-month follow-up at two study sites (France and UK) to assess the safety and efficacy of ProSavin after bilateral injection into the putamen of patients with Parkinson's disease.

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Purpose: StarGen is an equine infectious anemia virus (EIAV)-based lentiviral vector that expresses the photoreceptor-specific adenosine triphosphate (ATP)-binding cassette transporter (ABCA4) protein that is mutated in Stargardt disease (STGD1), a juvenile macular dystrophy. EIAV vectors are able to efficiently transduce rod and cone photoreceptors in addition to retinal pigment epithelium in the adult macaque and rabbit retina following subretinal delivery. The safety and biodistribution of StarGen following subretinal delivery in macaques and rabbits was assessed.

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The release of lentiviral vectors for clinical use requires the testing of vector material, production cells, and, if applicable, ex vivo-transduced cells for the presence of replication-competent lentivirus (RCL). Vectors derived from the nonprimate lentivirus equine infectious anemia virus (EIAV) have been directly administered to patients in several clinical trials, with no toxicity observed to date. Because EIAV does not replicate in human cells, and because putative RCLs derived from vector components within human vector production cells would most likely be human cell-tropic, we previously developed an RCL assay using amphotropic murine leukemia virus (MLV) as a surrogate positive control and human cells as RCL amplification/indicator cells.

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RetinoStat(®) is an equine infectious anemia virus-based lentiviral gene therapy vector that expresses the angiostatic proteins endostatin and angiostatin that is delivered via a subretinal injection for the treatment of the wet form of age-related macular degeneration. We initiated 6-month safety and biodistribution studies in two species; rhesus macaques and Dutch belted rabbits. After subretinal administration of RetinoStat the level of human endostatin and angiostatin proteins in the vitreous of treated rabbit eyes peaked at ∼1 month after dosing and remained elevated for the duration of the study.

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In Parkinson's disease, degeneration of specific neurons in the midbrain can cause severe motor deficits, including tremors and the inability to initiate movement. The standard treatment is administration of pharmacological agents that transiently increase concentrations of brain dopamine and thereby discontinuously modulate neuronal activity in the striatum, the primary target of dopaminergic neurons. The resulting intermittent dopamine alleviates parkinsonian symptoms but is also thought to cause abnormal involuntary movements, called dyskinesias.

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Article Synopsis
  • Pseudotyping viral vectors with VSV-G allows for efficient transduction across various cell types and species.
  • Two key factors influencing lentiviral vector transduction potential are the glycosylation status of VSV-G and the amount of glycoprotein on the virions.
  • VSV-G isoforms (VSV-G1 and VSV-G2) show differences in effectiveness, particularly impacting primate cells, with glycosylation enhancing expression in HEK293T cells, while the required amounts of VSV-G vary significantly across different cell types.
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Lentiviral vectors based on equine infectious anemia virus (EIAV) stably integrate into dividing and nondividing cells such as neurons, conferring long-term expression of their transgene. The integration profile of an EIAV vector was analyzed in dividing HEK293T cells, alongside an HIV-1 vector as a control, and compared to a random dataset generated in silico. A multivariate regression model was generated and the influence of the following parameters on integration site selection determined: (a) within/not within a gene, (b) GC content within 20 kb, (c) within 10 kb of a CpG island, (d) gene density within a 2-Mb window, and (e) chromosome number.

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The use of lentiviral vectors for gene transfer into hematopoietic stem cells has raised considerable interest as these vectors can permanently integrate their genome into quiescent cells. Vectors based on alternative lentiviruses would theoretically be safer than HIV-1-based vectors and could also be used in HIV-positive patients, minimizing the risk of generating replication-competent virus. Here we report the use of third-generation equine infectious anemia virus (EIAV)- and HIV-1-based vectors with minimal viral sequences and absence of accessory proteins.

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Motivation: A number of algorithms and analytical models have been employed to reduce the multidimensional complexity of DNA array data and attempt to extract some meaningful interpretation of the results. These include clustering, principal components analysis, self-organizing maps, and support vector machine analysis. Each method assumes an implicit model for the data, many of which separate genes into distinct clusters defined by similar expression profiles in the samples tested.

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The African swine fever virus (ASFV) j4R protein is expressed late during the virus replication cycle and is present in both the nucleus and the cytoplasm of infected cells. By using the yeast two-hybrid system, direct binding, and coprecipitation from cells, we showed that the j4R protein binds to the alpha chain of nascent polypeptide-associated complex (alpha NAC). Confocal microscopy indicated that a proportion of j4R and alpha NAC interact in areas close to the plasma membrane, as well as through the cytoplasm in cells.

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Five independent clones of the Propionibacterium acnes P-37 lipase gene (gehA) were obtained in Escherichia coli, and the gene was localized to a 2.75 kb Xhol fragment by subcloning. The five clones were shown to contain the same gene by Southern blotting with a DIG-labelled probe to gehA.

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