Molecular Therapy-Methods & Clinical Development最新文献

We sought to engineer mammalian cells to secrete nuclease activity as a step toward removing the need to purchase commercial nucleases as process additions in bioprocessing of AAV5 and AAV9 as gene therapy vectors. Engineering HeLa cells with a serratial nuclease transgene did not bring about nuclease activity in surrounding media whereas engineering serum-free, suspension-adapted HEK293-F cells with a staphylococcal nuclease transgene did result in detectable nuclease activity in surrounding media of the resultant stable transfectant cell line, 'NuPro-1S'. When cultivated in serum-free media, NuPro-1S cells yielded 3.06x10¹⁰ AAV5 viral genomes (vg) / mL via transient transfection, compared to 3.85x10⁹ vg /mL from the parental HEK293-F cell line. AAV9 production, followed by purification by ultracentrifugation, yielded 1.8x10¹³ vg /mL from NuPro-1S cells compared to 7.35x10¹² vg /mL from HEK293-F cells. AAV9 from both HEK293-F and NuPro-1S showed almost identical ability to transduce cells embedded in a scaffold tissue mimic or cells of mouse neonate brain tissue in-vivo. Comparison of agarose gel data indicated that the DNA content of AAV5 and AAV9 process streams from NuPro-1S cells was reduced by approximately 60% compared to HEK293-F cells. A similar reduction in HEK293-F cells was only achievable with a 50 U / mL Benzonase® treatment.

GM1-gangliosidosis (GM1) is a lysosomal storage disorder caused by mutations in the galactosidase beta 1 gene (GLB1) that leads to reduced β-galactosidase (β-gal) activity. This enzyme deficiency results in neuronal degeneration, developmental delay, and early death. A sensitive assay for the measurement of β-gal enzyme activity is required for the development of disease-modifying therapies. We have optimized fluorometric assays for quantitative analysis of β-gal activity in human cerebrospinal fluid (CSF) and serum for the development of a GLB1 gene replacement therapy. Assay analytical performance was characterized by assessing sensitivity, precision, accuracy, parallelism, specificity, and sample stability. Sensitivity of the CSF and serum β-gal activity assays were 0.05 nmol/mL/3hr and 0.20 nmol/mL/3hr, respectively. Assay precision represented by inter-assay percent coefficient of variation of the human CSF and serum was <15% and <20%, respectively. The effect of pre-analytical factors on β-gal activity was examined, and rapid processing and freezing of samples post-collection was critical to preserve enzyme activity. These assays enabled measurement of CSF and serum β-gal activities in both healthy individuals and patients with GM1-gangliosidosis. This CSF β-gal activity assay is the first of its kind with sufficient sensitivity to quantitatively measure β-gal enzyme activity in CSF samples from GM1 patients.

Lentiviral vector (LVV)-mediated cell and gene therapies have the potential to cure diseases that currently require lifelong intervention. However, the requirement for plasmid transfection hinders large-scale LVV manufacture. Moreover, large-scale plasmid production, testing and transfection all contribute to operational risk and the high cost associated with this therapeutic modality. Thus, we developed LVV packaging and producer cell lines, which reduce or eliminate the need for plasmid transfection during LVV manufacture. To develop a packaging cell line, lentiviral packaging genes were stably integrated by random integration of linearised plasmid DNA. Then, to develop EGFP- and anti-CD19 chimeric antigen receptor-encoding producer cell lines, transfer plasmids were integrated by transposase-mediated integration. Single cell isolation and testing were performed to isolate the top-performing clonal packaging and producer cell lines. Production of LVV that encode various cargo genes revealed consistency in the production performance of the packaging and producer cell lines compared to the industry-standard four-plasmid transfection method. By reducing or eliminating the requirement for plasmid transfection, while achieving production performance consistent with the current industry standard, the packaging and producer cell lines developed here can reduce costs and operational risks of LVV manufacture, thus increasing patient access to LVV-mediated cell and gene therapies.

Neuroinflammation is a miscreant in accelerating progression of many neurodegenerative diseases, including ALS. However, treatments targeting neuroinflammation alone have led to disappointing results in clinical trials. Both neuronal and non-neuronal cell types have been implicated in pathogenesis of ALS, and multiple studies have shown correction of each cell type has beneficial effect on disease outcome. Previously, we showed that AAV9-mediated SOD1 suppression in motor neurons and astrocytes significantly improves motor function and extends survival in ALS mouse models. Despite neuron and astrocyte correction, ALS mice still succumb to death with microgliosis observed in endpoint tissue. Therefore, we hypothesized that the optimal therapeutic approach will target and simultaneously correct motor neurons, astrocytes, and microglia. Here, we developed a novel approach to indirectly target microglia with Galectin-1 and combined this with our previously established AAV9.SOD1.shRNA treatment. We show Galectin-1 conditioning of SOD1^G93A microglia reduces inflammatory markers and rescues motor neuron death in vitro. When paired with SOD1 downregulation, we found a synergistic effect of combination treatment in vivo and show a significant extension of survival of SOD1^G93A mice over SOD1 suppression alone. These results highlight the importance of targeting inflammatory microglia as a critical component in future therapeutic development.

In vivo delivery of mRNA is promising for the study of gene expression and the treatment of diseases. Lipid nanoparticles (LNP) enable efficient delivery of mRNA constructs, but protein expression has been assumed to be limited to the liver. With specialized LNP, delivery to extrahepatic tissue occurs in small animal models, however it is unclear if global delivery of mRNA to all major organs is possible in humans, because delivery may be affected by differences in innate immune response and relative organ size. Furthermore, limited studies with LNP have been performed in large animal models, such as swine, due to their sensitivity to complement activation-related pseudoallergy (CARPA). In this study, we found that exogenous protein expression occurred in all major organs when swine were injected intravenously with a relatively low dose of mRNA encapsulated in a clinically relevant LNP formulation. Exogenous protein was detected in the liver, spleen, lung, heart, uterus, colon, stomach, kidney, small intestine, and brain of the swine without inducing CARPA. Furthermore, protein expression was detected in the bone marrow, including megakaryocytes, hematopoietic stem cells, granulocytes, and in circulating white blood cells and platelets. These results show that nearly all major organs contain exogenous protein expression and are viable targets for mRNA therapies.

Mucopolysaccharidosis type IVB (MPSIVB) is a lysosomal storage disorder caused by β-galactosidase (β-GAL) deficiency characterized by severe skeletal and neurological alterations without approved treatments. To develop hematopoietic stem progenitor cell-gene therapy (HSPC-GT) for MPSIVB, we designed lentiviral vectors (LVs) encoding human β-GAL to achieve supraphysiological release of the therapeutic enzyme in human HSPCs and metabolic correction of diseased cells. Transduced HSPCs displayed proper colony formation, proliferation, and differentiation capacity, but their progeny failed to release the enzyme at supraphysiological levels. Therefore, we tested alternative LVs to overexpress an enhanced β-GAL deriving from murine (LV-enhGLB1) and human selectively mutated GLB1 sequences (LV-mutGLB1). Only human HSPCs transduced with LV-enhGLB1 overexpressed β-GAL in vitro and in vivo without evidence of overexpression-related toxicity. Their hematopoietic progeny efficiently released β-GAL, allowing the cross-correction of defective cells, including skeletal cells. We found that the low levels of human GLB1 mRNA in human hematopoietic cells and the improved stability of the enhanced β-GAL contribute to the increased efficacy of LV-enhGLB1. Importantly, the enhanced β-GAL enzyme showed physiological lysosomal trafficking in human cells and was not associated with increased immunogenicity in vitro. These results support the use of LV-enhGLB1 for further HSPC-GT development and future clinical translation to treat MPSIVB multisystem disease.

Macrophage-based cell therapeutics are an emerging modality to treat cancer and repair tissue damage. A reproducible manufacturing and engineering process is central to fulfill their therapeutical potential. Here, we establish a robust macrophage manufacturing platform (Mo-Mac), and demonstrate that macrophage functionality can be enhanced by N1-methylpseudouridine (m1Ψ)-modified mRNA. Using single-cell transcriptomic analysis as an unbiased approach, we found that >90% cells in the final product were macrophages, and the rest primarily comprised T cells, B cells, natural killer cells, promyelocytes, promonocytes and hematopoietic stem cells. This analysis also guided the development of flow cytometry strategies to assess cell compositions in the manufactured product to meet requirements by the National Medical Products Administration. To modulate macrophage functionality, as an illustrative example, we examined whether the engulfment capability of macrophages could be enhanced by mRNA technology. We found that efferocytosis was increased in vitro when macrophages were electroporated with m1Ψ-modified mRNA encoding CD300LF (CD300LF-mRNA-macrophage). Consistently, in a mouse model of acute liver failure, CD300LF-mRNA-macrophage facilitated organ recovery from acetaminophen-induced hepatotoxicity. These results demonstrate a GMP-compliant macrophage manufacturing process, and indicate that macrophage can be engineered by versatile mRNA technology to achieve therapeutic goals.

Lamellar Ichthyosis (LI) is a chronic disease, mostly caused by mutations in TGM1 gene, marked by impaired skin barrier formation. No definitive therapies are available and current treatments aim at symptomatic relief. LI mouse models often fail to faithfully replicate the clinical and histopathological features of human skin conditions. To develop advanced therapeutic approaches, as combined ex vivo cell and gene therapy, we established a human cellular model of LI by efficient CRISPR-Cas9-mediated gene ablation of the TGM1 gene in human primary clonogenic keratinocytes. Gene edited cells showed complete absence of Transglutaminase-1 (TG1) expression and recapitulated a hyperkeratotic phenotype with most of the molecular hallmarks of LI in vitro. Using a SINγ-RV vector expressing transgenic TGM1 under the control of its own promoter, we tested an ex vivo gene therapy approach and validate the model of LI as a platform for pre-clinical evaluation studies. Gene-corrected TGM1-null keratinocytes displayed proper TG1 expression, enzymatic activity and cornified envelopes formation, hence restored proper epidermal architecture. Single cell multiomic analysis demonstrated proviral integrations in holoclone-forming epidermal stem cells, which are crucial to epidermal regeneration. This study serves as a proof-of-concept for assessing the potential of this therapeutic approach in treating TGM1 dependent LI.