Unknown,Transcriptomics,Genomics,Proteomics

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Process-sensitive sentinel genes as novel cell culture comparability metrics

ABSTRACT: Biotechnology-derived therapeutics manufacturing is highly regulated to assure product quality, safety and efficacy. Process conditions are closely monitored as they can influence product characteristics. Culture of mammalian cells at different scales is a vital part of biomanufacturing. Currently, scale up of bioreactors is largely done based on engineering parameters such as oxygen transfer and mixing characteristics. There is a lack of genomic translational studies in mammalian cell culture scale-up that can help delineate measurable cellular attributes for improved process understanding. These could be used for quantifying physiological response of cells due to changes in bioreactor environment. In this study, we identified 18 process-sensitive sentinel genes using microarray statistical analysis, which we further verified by qRT-PCR. These were differentially expressed transcripts between a typical 5 liter bench-scale bubble-aerated and impeller-agitated bioreactor and novel 35 mL high-throughput minibioreactors. Using expression changes and biochemical-pathway guidance of these sentinel genes, we were able to tune engineering parameters such that the improved scale-down resulted in both process parameter and sentinel gene profile convergence between the two systems, further solidifying the functionality evidence of these sentinel genes. This study serves as a starting point for developing qRT-PCR assays as comparability metrics that could be performed near-at-line during the cell culture process itself leading to enhanced process control. Additional broad applications of sentinel genes could be to validate different manufacturing facilities for the same product, and allow better process definition by fingerprinting the manufacturing process for more rapid biogenerics and vaccine approvals. We ran consecutive bioreactor (5L and HTCB) runs, each with an independent vial thaw, to achieve multiple biological replicates per time-point. Bioreactors were sampled approximately every 12 hours for RNA extraction. For the 5L bioreactors, microarray samples were run for day 1 (n=2), day 2 (n=2), day 3 (n=3), and day 3.5 (n=3). Here 2 or 3 of the three biological replicates run for each time-point were included in the analysis, based on >70% genes found. For the High-Throughput Controlled Minibioreactors (HTCB), microarray samples were run for day 1 (n=3), day 2 (n=3), day 3 (n=3), day 4 (n=2), and day 4.5 (n=2). Here 2 to 4 of the 4 biological replicate runs were included in the analysis, based on >70% genes found. We define early exponential as day 1, peak exponential as day 2 and day 3 and late stationary as day 3.5.

ORGANISM(S): Mus musculus

SUBMITTER: Bhargavi Kondragunta

PROVIDER: E-GEOD-33063 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Project description:There is a great need for setting novel measurable attributes at the cell physiological level in a scalable biopharmaceutical production process to be able to predict the process outcomes and improve process understanding. In a biologic production process, changes in culture environment due to several factors such as shear and bubble induced damage from gas sparging and agitation are known to occur. There is a gap in the knowledge of cellular response due to varying bioreactor environment itself during the course of cell culture, from lag-phase to log-phase to stationary-phase in culture. With the emergence of micro-arrays as tools for exploring cell physiological changes, it opens the possibility for studying the effect of bioreactor culture environment itself on the cell substrate. Such information could be eventually used to designate gene transcripts as biomarkers for cell status in a controlled bioreactor system. A model 5L bench-scale bubble aerated and impeller agitated bioreactor system was used to study gene expression profiles of a hybridoma cell line during the time-course of batch culture. Gene expression profiles that were variable from early-to-late in batch culture, as well as invariant gene profiles were summarized using microarray findings. Typical cellular functions studied were oxidative stress response, DNA damage response, apoptosis, antioxidant activity, cellular metabolism, and protein folding. These findings were also verified with a more rigorous semi-quantitative RT-PCR technique. The results of this study suggest that under predefined bioreactor culture conditions, significant gene changes from lag to log to stationary phase could be identified, which could then be used to track the culture state. We ran consecutive 5L bioreactor runs, each with an independent vial thaw, to achieve multiple biological replicates per time-point. Bioreactors were sampled approximately every 12 hours for RNA extraction. For the 5L bioreactors, microarray samples were run for day 1 (n=2), day 2 (n=2), day 3 (n=3), and day 3.5 (n=3). Here 2 or 3 of the three biological replicates run for each time-point were included in the analysis, based on >70% genes found. We define early exponential as day 1, peak exponential as day 2 and day 3 and late stationary as day 3.5.

Project description:The p53 homologue, p63, is critical for normal epidermal development. While overexpression of deltaNp63alpha has been reported in squamous cell cancers, the contribution of p63 to cancer pathogenesis remains unclear. We previously demonstrated that overexpressed deltaNp63alpha aberrantly maintains proliferation of primary epidermal keratinocytes under conditions that normally induce growth arrest and differentiation. To identify target genes impacted by dysregulated deltaNp63alpha that may contribute to squamous cancer development and progression, microarray analyses were performed. Herein we report that elevated deltaNp63alpha differentially regulates genes in primary mouse keratinocytes involved in a variety of cellular functions, including cell cycle regulation, differentiation, skin barrier formation and function, apoptosis, host defense/inflammation, adhesion, migration and invasion. Of note, multiple protease inhibitor mRNAs were coordinately downregulated under both proliferating and differentiating culture conditions. These downregulated genes include two serine protease inhibitors: maspin (serpinB5) and plasminogen activator inhibitor-2 (PAI-2; serpinB2), as well as a tissue inhibitor of metalloproteinase-3 (TIMP-3). Correspondingly, secreted levels of TIMP-3 and PAI-2 protein declined in the presence of dysregulated deltaNp63alpha, while secreted maspin protein levels remained stable. Intracellular maspin protein expression decreased in response to overexpressed deltaNp63alpha, as did intracellular PAI-2. Unlike PAI-2 and maspin, TIMP-3 protein was not detected intracellularly in control or deltaNp63alpha-overexpressing keratinocytes, supporting a solely extracellular function for TIMP-3. Electrophoretic mobility shift assays using a p53/p63 consensus DNA binding sequence from the maspin promoter revealed binding of an endogenous transcription factor(s) to the consensus sequence in normal keratinocytes that was disrupted by overexpressed deltaNp63alpha. This binding was also interrupted by the addition of a p73 antibody, but not antibodies to p63 or p53, and was absent in samples derived from p73(-/-) keratinocytes, confirming p73 as a constituent of the endogenous transcription factor complex. These data suggest protease inhibitors as novel targets of dysregulated deltaNp63alpha in cancer pathogenesis. Keratinocytes were transduced with adenoviruses encoding deltaNp63alpha. Keratinocytes were either maintained in low calcium conditions (0.05 mM for 24 hours) (n=6) or high calcium conditions (0.12 mM for 24 hours) (n=6). Control samples consisted of keratinocytes transduced with adenoviruses encoding beta-galactosidase also treated with low calcium (n=6) and high calcium (n=6) conditions. Twelve technical repeat microarray experiments were conducted, pairing high-calcium deltaNp63alpha samples with high-calcium beta-galactosidase samples (n=6) and low-calcium deltaNp63alpha samples with low-calcium beta-galactosidase samples (n=6). Six of the technical repeats were conducted as reverse-fluoro experiments.

Project description:Abstract: Hematopoietic stem cells (HSCs) are used in transplantation therapy to reconstitute the hematopoietic system. Human cord blood (hCB) transplantation has emerged as an attractive alternative treatment option when traditional HSC sources are unavailable, however, the absolute number of hCB HSCs transplanted is significantly lower than bone marrow or mobilized peripheral blood stem cells (MPBSCs). We previously demonstrated that dimethyl-prostaglandin E2 (dmPGE2) increased HSCs in vertebrate models. Here, we describe preclinical analyses of the therapeutic potential of dmPGE2-treatment using human and non-human primate HSCs. dmPGE2 significantly increased total human hematopoietic colony formation in vitro and enhanced engraftment of unfractionated and CD34+ hCB following xenotransplantation. In non-human primate autologous transplantation, dmPGE2-treated CD34+ MPBSCs showed stable multilineage engraftment over one year post-infusion. Together, our analyses indicated that dmPGE2 mediates conserved responses in HSCs from human and non-human primates, and provided sufficient preclinical information to support proceeding to an FDA-approved phase 1 clinical trial. In order to identify the potential mechanism of action of dmPGE2 on gene expression and HSC function, and to possibly explain the muted response of rhesus CD34+ MPBSCs to dmPGE2 exposure, microarray gene expression analysis was conducted. Human and rhesus CD34+ MPBSCs were exposed to DMSO control or dmPGE2 at a dose of either 10 and 50 uM as described above, and processed for microarray analysis at 0, 2, 6, 12 and 24 hours post treatment. Four human donors contributed 8 to 10 samples each at varying time points and dosage for a total of 37 samples (2 samples were technical repeats). Six rhesus macaques contributed 3 to 9 samples each at varying time points and dosage for a total of 28 samples (4 samples were technical repeats). Pooled PBMC's from 6 donors aphereses were used as a reference sample.

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Process-sensitive sentinel genes as novel cell culture comparability metrics

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