Comprehensive mRNA-sequencing-based characterization of three HEK-293 cell lines during an rAAV production process for Gene Therapy Applications
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ABSTRACT: Human embryonal kidney cells (HEK-293) are the most common host cells used for transient recombinant adeno-associated virus (rAAV) production in pharmaceutical industry. To better cover the expected gene therapy product demands in the future, different traditional strategies such as cell line sub-cloning and/or addition of chemical substances to the fermentation media have been used to maximize titers and improve product quality. A more effective and advanced approach to boost yield can be envisaged by characterizing the transcriptome of different HEK-293 cell line pedigrees with distinct rAAV productivity patterns to subsequently identify potential gene targets for cell engineering. In this work, the mRNA expression profile of three HEK-293 cell lines, resulting in various yields during a fermentation batch process for rAAV production, was investigated to gain basic insight into cell variability and eventually to identify genes that correlate with productivity. Mock runs using only transfection reagents were performed in parallel as a control. We found significant differences in gene regulatory behaviors between the three cell lines at different growth and production stages. The evaluation of these transcriptomics profiles combined with collected in-process control parameters and titers shed some light on potential cell engineering targets to maximize transient production of rAAV in HEK-293 cells Comparison of three HEK-293 suspension cell lines transcriptomics during an AAV production process
Project description:Recombinant adeno-associated virus (rAAV) is a widely used viral vector for gene therapy. Despite its clinical efficacy, the manufacturing of rAAV faces challenges in productivity and quality, leading to limited availability. To address the growing demand, next-generation process development should be informed by a mechanistic understanding of the cellular response to rAAV. In this study, we performed transcriptomic analysis of 5 cell lines with variable capacities for rAAV production. Using an intersectional approach, we assessed the transcriptional response to rAAV production and compared transcriptional profiles between high and baseline producers to identify possible targets for enhancing production. Modulation of cell cycle and nucleosome components suggested a reduction of proliferative capacity and a shift toward DNA replication to support rAAV production. During rAAV production, we observed upregulation of several core functions including transcription, stress response, and Golgi and endoplasmic reticulum organization. Conversely, inhibitors of DNA-binding proteins and mitochondrial components were consistently downregulated during rAAV production. We next performed a drug connectivity analysis of these results and identified 5 classes of drugs predicted to enhance rAAV production. Validation studies confirmed the efficacy of HDAC and microtubule inhibitors. Our data uncover novel and previously identified pathways that may enhance rAAV productivity, potentially enabling a path to engineer improved processes and cell lines for higher yields and better quality rAAV production.
Project description:We performed absolute quantification (AQUA) of viral proteins by targeted quantitative proteomics and conducted tandem mass tag (TMT)-based proteomics on the three rAAV and wtAAV production systems to identify potential factors limiting rAAV productivity in HEK293 cells
Project description:Comparison of the gene expression profiles of a recombinant protein producing Hek 293 cell line (referred to as producer) and its non-producing parental cell line Hek293F (referred to as non-producer). The parental cell line was obtained from Invitrogen, Carlsbad, CA. The producer was transfected with a heavy chain variable region fused to the Fc region of a human IgG (dAb-Fc). The aim of this study was to gain a better understanding of the process of recombinant protein production in Hek293 cells and to identify targets for the engineering of an improved host cell line.
Project description:The aim of this study is to discover genes regulated by miR-204. Differential gene expression in HEK-293 cells transfected with miR-204-mimic compared to HEK-293 cells transfected with control oligo (HEK-293 control) was analyzed using the Agilent Human Whole Genome 4x44K gene expression array (Agilent Technologies, Santa Clara, CA).
Project description:Comprehensive mRNA-sequencing-based characterization of three HEK-293 cell lines during an rAAV production process for Gene Therapy Applications
Project description:Recombinant adeno-associated viruses (rAAVs) are the predominant gene therapy vector. Several rAAV vectored therapies have achieved regulatory approval, but production of sufficient rAAV quantities remains difficult. The AAV Rep proteins, which are essential for genome replication and packaging, represent a promising engineering target for improvement of rAAV production but remain underexplored. To gain a comprehensive understanding of the Rep proteins and their mutational landscape, we assayed the effects of all 39,297 possible single codon mutations to the AAV2 rep gene on AAV2 production. Most beneficial variants are not observed in nature, indicating that improved production may require synthetic mutations. Additionally, the effects of AAV2 rep mutations were largely consistent across capsid serotypes, suggesting that production benefits are capsid independent. Our results provide a detailed sequence-to-function map that enhances our understanding of Rep protein function and lays the groundwork for Rep engineering and enhancement of large scale gene therapy production.
Project description:BACKGROUND:Isobutanol is a promising next generation biofuel with demonstrated high yield microbial production, but the toxicity of this molecule reduces fermentation volumetric productivity and final titers. Organic solvent tolerance is a complex, multigenic phenotype that has been recalcitrant to rational engineering approaches. We apply experimental evolution followed by genome resequencing and a gene expression study to elucidate genetic bases on adaptation to exogenous isobutanol stress. RESULTS:The adaptations acquired in our evolved lineages exhibit antagonistic pleiotropy between minimal and rich medium, and appear to be specific to the effects of longer chain alcohols. By examining genotypic adaptation in multiple independent lineages, we find evidence of parallel evolution in hfq, mdh, acrAB, gatYZABCD, and rph genes. Many isobutanol tolerant lineages show reduced rpoS activity, perhaps related to mutations in hfq or acrAB. Consistent with the complex, multigenic nature of solvent tolerance, we observe adaptations in a diversity of cellular processes. Many adaptations appear to involve epistasis between different mutations, implying a rugged fitness landscape for isobutanol tolerance. We observe a trend of evolution targeting post-transcriptional regulation and high centrality nodes of biochemical networks. Collectively, the genotypic adaptations we observe suggest mechanisms of adaptation to isobutanol stress based on remodelling the cell envelope and surprisingly, stress response attenuation. CONCLUSIONS:We have discovered a set of genotypic adaptations that confer increased tolerance to exogenous isobutanol stress. Our results are immediately useful to efforts to engineer more isobutanol tolerant host strains of E. coli for isobutanol production. We suggest that rpoS and post-transcriptional regulators, such as hfq, RNA helicases, and sRNAs may be interesting mutagenesis targets for futurue global phenotype engineering. Two strains (WT strain and G3.2 mutant strain), each with two culture conditions (with and without isobutanol in medium). Three biological replicates for each strain/culture condition. Twelve samples in total.
Project description:We used high-throughput sequencing to investigate the genome-wide transcriptional response in human cells to treatment with Borrelia burgdorferi. We chose a time point of 72 h as ticks feed on their host for several days and at the same time the early response in Lyme disease is expected to occur at this time period at a cellular level. We found that the two cell models studied (HUVEC and HEK-293 cells) had significantly different responses. More significantly differentially expressed genes (69 in total) were found in HUVEC cells than in HEK-293 cells (8 in total). Functional analysis indicated induction of the immune response in HUVEC and suggest changes in the extracellular matrix in HEK-293.
Project description:Comparison of the gene expression profiles of a recombinant protein producing Hek 293 cell line (referred to as producer) and its non-producing parental cell line Hek293F (referred to as non-producer). The parental cell line was obtained from Invitrogen, Carlsbad, CA. The producer was transfected with a heavy chain variable region fused to the Fc region of a human IgG (dAb-Fc). The aim of this study was to gain a better understanding of the process of recombinant protein production in Hek293 cells and to identify targets for the engineering of an improved host cell line. Duplicate samples for RNA extraction were taken at four time points (approximately 30, 43, 51 and 67 hours after inoculation of the bioreactor) during the exponential phase of batch bioreactor cultures. Only one of these technical duplicates was analysed. Three bioreactor cultures were performed for each cell line representing three biological replicates resulting in 12 (3 x 4) samples per cell line.
Project description:This series of microarray experiments monitored the gene expression profiles for monoclonal cell lines (derived from HEK-293 parental cell culture) with high (H1, H15, H24, H36, H39) or low (L3, L28, L29) levels of store-operated Ca2+ entry (SOCE). For selection of clones, HEK-293 cells were loaded with indo-1 and sorted by FACS on the basis of their cyclopiazonic acid (CPA)-stimulated Ca2+ entry. Monoclonal cell lines were selected from the sorted cells and their levels of SOCE confirmed by monitoring thapsigargin-stimulated Ba2+ entry. Total RNA was extracted from cells immediately after removal from their growth environment. RNA was processed and hybridized to the Affymetrix HG-U133A chip. Two parallel hybridizations were done for each RNA preparation from each monoclonal cell line or from the parental HEK-293 cell culture. Keywords: parallel sample