1
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Gaugler L, Hofmann S, Schlüter M, Takors R. Mimicking CHO large-scale effects in the single multicompartment bioreactor: A new approach to access scale-up behavior. Biotechnol Bioeng 2024; 121:1244-1256. [PMID: 38192095 DOI: 10.1002/bit.28647] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 12/04/2023] [Accepted: 12/21/2023] [Indexed: 01/10/2024]
Abstract
During the scale-up of biopharmaceutical production processes, insufficiently predictable performance losses may occur alongside gradients and heterogeneities. To overcome such performance losses, tools are required to explain, predict, and ultimately prohibit inconsistencies between laboratory and commercial scale. In this work, we performed CHO fed-batch cultivations in the single multicompartment bioreactor (SMCB), a new scale-down reactor system that offers new access to study large-scale heterogeneities in mammalian cell cultures. At volumetric power inputs of 20.4-1.5 W m-3, large-scale characteristics like long mixing times and dissolved oxygen (DO) heterogeneities were mimicked in the SMCB. Compared to a reference bioreactor (REFB) set-up, the conditions in the SMCB provoked an increase in lactate accumulation of up to 87%, an increased glucose uptake, and reduced viable cell concentrations in the stationary phase. All are characteristic for large-scale performance. The unique possibility to distinguish between the effects of changing power inputs and observed heterogeneities provided new insights into the potential reasons for altered product quality attributes. Apparently, the degree of galactosylation in the evaluated glycan patterns changed primarily due to the different power inputs rather than the provoked heterogeneities. The SMCB system could serve as a potent tool to provide new insights into scale-up behavior and to predict cell line-specific drawbacks at an early stage of process development.
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Affiliation(s)
- Lena Gaugler
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
| | - Sebastian Hofmann
- Institute of Multiphase Flows, Hamburg University of Technology, Hamburg, Germany
| | - Michael Schlüter
- Institute of Multiphase Flows, Hamburg University of Technology, Hamburg, Germany
| | - Ralf Takors
- Institute of Biochemical Engineering, University of Stuttgart, Stuttgart, Germany
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2
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Belliveau J, Papoutsakis ET. The microRNomes of Chinese hamster ovary (CHO) cells and their extracellular vesicles, and how they respond to osmotic and ammonia stress. Biotechnol Bioeng 2023; 120:2700-2716. [PMID: 36788116 DOI: 10.1002/bit.28356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 01/23/2023] [Accepted: 02/12/2023] [Indexed: 02/16/2023]
Abstract
A new area of focus in Chinese hamster ovary (CHO) biotechnology is the role of small (exosomes) and large (microvesicles or microparticles) extracellular vesicles (EVs). CHO cells in culture exchange large quantities of proteins and RNA through these EVs, yet the content and role of these EVs remain elusive. MicroRNAs (miRs or miRNA) are central to adaptive responses to stress and more broadly to changes in culture conditions. Given that EVs are highly enriched in miRs, and that EVs release large quantities of miRs both in vivo and in vitro, EVs and their miR content likely play an important role in adaptive responses. Here we report the miRNA landscape of CHO cells and their EVs under normal culture conditions and under ammonia and osmotic stress. We show that both cells and EVs are highly enriched in five miRs (among over 600 miRs) that make up about half of their total miR content, and that these highly enriched miRs differ significantly between normal and stress culture conditions. Notable is the high enrichment in miR-92a and miR-23a under normal culture conditions, in contrast to the high enrichment in let-7 family miRs (let-7c, let-7b, and let-7a) under both stress conditions. The latter suggests a preserved stress-responsive function of the let-7 miR family, one of the most highly preserved miR families across species, where among other functions, let-7 miRs regulate core oncogenes, which, depending on the biological context, may tip the balance between cell cycle arrest and apoptosis. While the expected-based on their profound enrichment-important role of these highly enriched miRs remains to be dissected, our data and analysis constitute an important resource for exploring the role of miRs in cell adaptation as well as for synthetic applications.
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Affiliation(s)
- Jessica Belliveau
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
| | - Eleftherios T Papoutsakis
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
- Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, USA
- Department of Biological Sciences, University of Delaware, Newark, Delaware, USA
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3
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Jiménez del Val I, Kyriakopoulos S, Albrecht S, Stockmann H, Rudd PM, Polizzi KM, Kontoravdi C. CHOmpact: A reduced metabolic model of Chinese hamster ovary cells with enhanced interpretability. Biotechnol Bioeng 2023; 120:2479-2493. [PMID: 37272445 PMCID: PMC10952303 DOI: 10.1002/bit.28459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 05/19/2023] [Accepted: 05/22/2023] [Indexed: 06/06/2023]
Abstract
Metabolic modeling has emerged as a key tool for the characterization of biopharmaceutical cell culture processes. Metabolic models have also been instrumental in identifying genetic engineering targets and developing feeding strategies that optimize the growth and productivity of Chinese hamster ovary (CHO) cells. Despite their success, metabolic models of CHO cells still present considerable challenges. Genome-scale metabolic models (GeMs) of CHO cells are very large (>6000 reactions) and are difficult to constrain to yield physiologically consistent flux distributions. The large scale of GeMs also makes the interpretation of their outputs difficult. To address these challenges, we have developed CHOmpact, a reduced metabolic network that encompasses 101 metabolites linked through 144 reactions. Our compact reaction network allows us to deploy robust, nonlinear optimization and ensure that the computed flux distributions are physiologically consistent. Furthermore, our CHOmpact model delivers enhanced interpretability of simulation results and has allowed us to identify the mechanisms governing shifts in the anaplerotic consumption of asparagine and glutamate as well as an important mechanism of ammonia detoxification within mitochondria. CHOmpact, thus, addresses key challenges of large-scale metabolic models and will serve as a platform to develop dynamic metabolic models for the control and optimization of biopharmaceutical cell culture processes.
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Affiliation(s)
| | - Sarantos Kyriakopoulos
- Manufacturing Science and TechnologyBioMarin PharmaceuticalCorkIrelandIreland
- Present address:
Drug Product DevelopmentJanssen PharmaceuticalsSchaffhausenSwitzerland
| | - Simone Albrecht
- GlycoScience GroupNational Institute for Bioprocessing Research and TrainingDublinIreland
| | - Henning Stockmann
- GlycoScience GroupNational Institute for Bioprocessing Research and TrainingDublinIreland
| | - Pauline M. Rudd
- GlycoScience GroupNational Institute for Bioprocessing Research and TrainingDublinIreland
- Present address:
Bioprocessing Technology InstituteAgency for Science, Technology and Research (A*STAR)SingaporeSingapore
| | - Karen M. Polizzi
- Department of Chemical EngineeringImperial College LondonLondonUK
| | - Cleo Kontoravdi
- Department of Chemical EngineeringImperial College LondonLondonUK
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4
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Chitwood DG, Uy L, Fu W, Klaubert SR, Harcum SW, Saski CA. Dynamics of Amino Acid Metabolism, Gene Expression, and Circulomics in a Recombinant Chinese Hamster Ovary Cell Line Adapted to Moderate and High Levels of Extracellular Lactate. Genes (Basel) 2023; 14:1576. [PMID: 37628627 PMCID: PMC10454118 DOI: 10.3390/genes14081576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 08/27/2023] Open
Abstract
The accumulation of metabolic wastes in cell cultures can diminish product quality, reduce productivity, and trigger apoptosis. The limitation or removal of unintended waste products from Chinese hamster ovary (CHO) cell cultures has been attempted through multiple process and genetic engineering avenues with varied levels of success. One study demonstrated a simple method to reduce lactate and ammonia production in CHO cells with adaptation to extracellular lactate; however, the mechanism behind adaptation was not certain. To address this profound gap, this study characterizes the phenotype of a recombinant CHO K-1 cell line that was gradually adapted to moderate and high levels of extracellular lactate and examines the genomic content and role of extrachromosomal circular DNA (eccDNA) and gene expression on the adaptation process. More than 500 genes were observed on eccDNAs. Notably, more than 1000 genes were observed to be differentially expressed at different levels of lactate adaptation, while only 137 genes were found to be differentially expressed between unadapted cells and cells adapted to grow in high levels of lactate; this suggests stochastic switching as a potential stress adaptation mechanism in CHO cells. Further, these data suggest alanine biosynthesis as a potential stress-mitigation mechanism for excess lactate in CHO cells.
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Affiliation(s)
- Dylan G. Chitwood
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (D.G.C.); (L.U.); (S.W.H.)
| | - Lisa Uy
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (D.G.C.); (L.U.); (S.W.H.)
| | - Wanfang Fu
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634, USA;
| | - Stephanie R. Klaubert
- Department of Chemical & Biomolecular Engineering, Clemson University, Clemson, SC 29634, USA;
| | - Sarah W. Harcum
- Department of Bioengineering, Clemson University, Clemson, SC 29634, USA; (D.G.C.); (L.U.); (S.W.H.)
- Department of Chemical & Biomolecular Engineering, Clemson University, Clemson, SC 29634, USA;
| | - Christopher A. Saski
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC 29634, USA;
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5
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Papež M, Jiménez Lancho V, Eisenhut P, Motheramgari K, Borth N. SLAM-seq reveals early transcriptomic response mechanisms upon glutamine deprivation in Chinese hamster ovary cells. Biotechnol Bioeng 2023; 120:970-986. [PMID: 36575109 DOI: 10.1002/bit.28320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/30/2022] [Accepted: 12/25/2022] [Indexed: 12/29/2022]
Abstract
Mammalian cells frequently encounter subtle perturbations during recombinant protein production. Identifying the genetic factors that govern the cellular stress response can facilitate targeted genetic engineering to obtain production cell lines that demonstrate a higher stress tolerance. To simulate nutrient stress, Chinese hamster ovary (CHO) cells were transferred into a glutamine(Q)-free medium and transcriptional dynamics using thiol(SH)-linked alkylation for the metabolic sequencing of RNA (SLAM-seq) along with standard RNA-seq of stressed and unstressed cells were investigated. The SLAM-seq method allows differentiation between actively transcribed, nascent mRNA, and total (previously present) mRNA in the sample, adding an additional, time-resolved layer to classic RNA-sequencing. The cells tackle amino acid (AA) limitation by inducing the integrated stress response (ISR) signaling pathway, reflected in Atf4 overexpression in the early hours post Q deprivation, leading to subsequent activation of its targets, Asns, Atf3, Ddit3, Eif4ebp1, Gpt2, Herpud1, Slc7a1, Slc7a11, Slc38a2, Trib3, and Vegfa. The GCN2-eIF2α-ATF4 pathway is confirmed by a significant halt in transcription of translation-related genes at 24 h post Q deprivation. The downregulation of lipid synthesis indicates the inhibition of the mTOR pathway, further confirmed by overexpression of Sesn2. Furthermore, SLAM-seq detects short-lived transcription factors, such as Egr1, that would have been missed in standard experimental designs with RNA-seq. Our results describe the successful establishment of SLAM-seq in CHO cells and therefore facilitate its future use in other scenarios where dynamic transcriptome profiling in CHO cells is essential.
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Affiliation(s)
- Maja Papež
- Austrian Centre of Industrial Biotechnology (acib GmbH), Graz, Austria
| | | | - Peter Eisenhut
- Austrian Centre of Industrial Biotechnology (acib GmbH), Graz, Austria
| | | | - Nicole Borth
- Austrian Centre of Industrial Biotechnology (acib GmbH), Graz, Austria
- University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
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6
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Cordova LT, Dahodwala H, Elliott KS, Baik J, Odenewelder DC, Nmagu D, Skelton BA, Uy L, Klaubert SR, Synoground BF, Chitwood DG, Dhara VG, Naik HM, Morris CS, Yoon S, Betenbaugh M, Coffman J, Swartzwelder F, Gillmeister MP, Harcum SW, Lee KH. Generation of reference cell lines, media, and a process platform for CHO cell biomanufacturing. Biotechnol Bioeng 2023; 120:715-725. [PMID: 36411514 DOI: 10.1002/bit.28290] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 11/03/2022] [Accepted: 11/17/2022] [Indexed: 11/23/2022]
Abstract
Due to the favorable attributes of Chinese hamster ovary (CHO) cells for therapeutic proteins and antibodies biomanufacturing, companies generate proprietary cells with desirable phenotypes. One key attribute is the ability to stably express multi-gram per liter titers in chemically defined media. Cell, media, and feed diversity has limited community efforts to translate knowledge. Moreover, academic, and nonprofit researchers generally cannot study "industrially relevant" CHO cells due to limited public availability, and the time and knowledge required to generate such cells. To address these issues, a university-industrial consortium (Advanced Mammalian Biomanufacturing Innovation Center, AMBIC) has acquired two CHO "reference cell lines" from different lineages that express monoclonal antibodies. These reference cell lines have relevant production titers, key performance outcomes confirmed by multiple laboratories, and a detailed technology transfer protocol. In commercial media, titers over 2 g/L are reached. Fed-batch cultivation data from shake flask and scaled-down bioreactors is presented. Using productivity as the primary attribute, two academic sites aligned with tight reproducibility at each site. Further, a chemically defined media formulation was developed and evaluated in parallel to the commercial media. The goal of this work is to provide a universal, industrially relevant CHO culture platform to accelerate biomanufacturing innovation.
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Affiliation(s)
- Lauren T Cordova
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Hussain Dahodwala
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,National Institute for Innovation in Manufacturing Biopharmaceuticals, Newark, Delaware, USA
| | - Kathryn S Elliott
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
| | - Jongyoun Baik
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,Department of Biological Sciences and Bioengineering, Inha University, Incheon, South Korea
| | | | - Douglas Nmagu
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA
| | - Bradley A Skelton
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
| | - Lisa Uy
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
| | - Stephanie R Klaubert
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, South Carolina, USA
| | | | - Dylan G Chitwood
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
| | - Venkata Gayatri Dhara
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Harnish Mukesh Naik
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | - Caitlin S Morris
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, Massachusetts, USA
| | - Seongkyu Yoon
- Department of Chemical Engineering, University of Massachusetts Lowell, Lowell, Massachusetts, USA
| | - Michael Betenbaugh
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland, USA
| | | | | | | | - Sarah W Harcum
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
| | - Kelvin H Lee
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, USA.,National Institute for Innovation in Manufacturing Biopharmaceuticals, Newark, Delaware, USA
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7
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Chitwood DG, Wang Q, Klaubert SR, Green K, Wu CH, Harcum SW, Saski CA. Microevolutionary dynamics of eccDNA in Chinese hamster ovary cells grown in fed-batch cultures under control and lactate-stressed conditions. Sci Rep 2023; 13:1200. [PMID: 36681715 PMCID: PMC9862248 DOI: 10.1038/s41598-023-27962-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 01/10/2023] [Indexed: 01/22/2023] Open
Abstract
Chinese hamster ovary (CHO) cell lines are widely used to manufacture biopharmaceuticals. However, CHO cells are not an optimal expression host due to the intrinsic plasticity of the CHO genome. Genome plasticity can lead to chromosomal rearrangements, transgene exclusion, and phenotypic drift. A poorly understood genomic element of CHO cell line instability is extrachromosomal circular DNA (eccDNA) in gene expression and regulation. EccDNA can facilitate ultra-high gene expression and are found within many eukaryotes including humans, yeast, and plants. EccDNA confers genetic heterogeneity, providing selective advantages to individual cells in response to dynamic environments. In CHO cell cultures, maintaining genetic homogeneity is critical to ensuring consistent productivity and product quality. Understanding eccDNA structure, function, and microevolutionary dynamics under various culture conditions could reveal potential engineering targets for cell line optimization. In this study, eccDNA sequences were investigated at the beginning and end of two-week fed-batch cultures in an ambr®250 bioreactor under control and lactate-stressed conditions. This work characterized structure and function of eccDNA in a CHO-K1 clone. Gene annotation identified 1551 unique eccDNA genes including cancer driver genes and genes involved in protein production. Furthermore, RNA-seq data is integrated to identify transcriptionally active eccDNA genes.
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Affiliation(s)
- Dylan G Chitwood
- Department of Bioengineering, Clemson University, Clemson, SC, USA
| | - Qinghua Wang
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Stephanie R Klaubert
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, SC, USA
| | - Kiana Green
- Department of Biological Sciences, University of South Carolina, Columbia, SC, USA
| | - Cathy H Wu
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, DE, USA
| | - Sarah W Harcum
- Department of Bioengineering, Clemson University, Clemson, SC, USA
- Department of Chemical and Biomolecular Engineering, Clemson University, Clemson, SC, USA
| | - Christopher A Saski
- Department of Plant and Environmental Sciences, Clemson University, Clemson, SC, USA.
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8
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Zhao M, Aweya JJ, Feng Q, Zheng Z, Yao D, Zhao Y, Chen X, Zhang Y. Ammonia stress affects the structure and function of hemocyanin in Penaeus vannamei. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2022; 241:113827. [PMID: 36068754 DOI: 10.1016/j.ecoenv.2022.113827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 06/19/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Anthropogenic factors and climate change have serious effects on the aquatic ecosystem and aquaculture. Among water pollutants, ammonia has the greatest impact on aquaculture organisms such as penaeid shrimp because it makes them more susceptible to infections. In this study, we explored the effects of ammonia stress (0, 50, 100, and 150 mg/L) on the molecular structure and functions of the multifunctional respiratory protein hemocyanin (HMC) in Penaeus vannamei. While the mRNA expression of Penaeus vannamei hemocyanin (PvHMC) was up-regulated after ammonia stress, both plasma hemocyanin protein and oxyhemocyanin (OxyHMC) levels decreased. Moreover, ammonia stress changed the molecular structure of hemocyanin, modulated the expression of protein phosphatase 2 A (PP2A) and casein kinase 2α (CK2α) to regulate the phosphorylation modification of hemocyanin, and enhanced its degradation into fragments by trypsin. Under moderate ammonia stress conditions, hemocyanin also undergoes glycosylation to improve its in vitro antibacterial activity and binding with Gram-negative (Vibrio parahaemolyticus) and Gram-positive (Staphylococcus aureus) bacteria, albeit differently. The current findings indicate that P. vannamei hemocyanin undergoes adaptive molecular modifications under ammonia stress enabling the shrimp to survive and counteract the consequences of the stress.
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Affiliation(s)
- Mingming Zhao
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China
| | - Jude Juventus Aweya
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; College of Ocean Food and Biological Engineering, Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Jimei University, Xiamen 361021, Fujian, China
| | - Qian Feng
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China
| | - Zhihong Zheng
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China
| | - Defu Yao
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China
| | - Yongzhen Zhao
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Nanning 530021, China
| | - Xiuli Chen
- Guangxi Academy of Fishery Sciences, Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Nanning 530021, China
| | - Yueling Zhang
- Institute of Marine Sciences and Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou 515063, China; Southern Marine Science and Engineering Guangdong Laboratory, Guangzhou 511458, China.
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9
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Cortada-Garcia J, Haggarty J, Moses T, Daly R, Alison Arnold S, Burgess K. On-line untargeted metabolomics monitoring of an E. coli succinate fermentation process. Biotechnol Bioeng 2022; 119:2757-2769. [PMID: 35798686 PMCID: PMC9541951 DOI: 10.1002/bit.28173] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 06/19/2022] [Indexed: 11/08/2022]
Abstract
The real‐time monitoring of metabolites (RTMet) is instrumental for the industrial production of biobased fermentation products. This study shows the first application of untargeted on‐line metabolomics for the monitoring of undiluted fermentation broth samples taken automatically from a 5 L bioreactor every 5 min via flow injection mass spectrometry. The travel time from the bioreactor to the mass spectrometer was 30 s. Using mass spectrometry allows, on the one hand, the direct monitoring of targeted key process compounds of interest and, on the other hand, provides information on hundreds of additional untargeted compounds without requiring previous calibration data. In this study, this technology was applied in an Escherichia coli succinate fermentation process and 886 different m/z signals were monitored, including key process compounds (glucose, succinate, and pyruvate), potential biomarkers of biomass formation such as (R)‐2,3‐dihydroxy‐isovalerate and (R)‐2,3‐dihydroxy‐3‐methylpentanoate and compounds from the pentose phosphate pathway and nucleotide metabolism, among others. The main advantage of the RTMet technology is that it allows the monitoring of hundreds of signals without the requirement of developing partial least squares regression models, making it a perfect tool for bioprocess monitoring and for testing many different strains and process conditions for bioprocess development.
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Affiliation(s)
- Joan Cortada-Garcia
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH8 9AB, United Kingdom
| | - Jennifer Haggarty
- Institute of Infection, Immunity and Inflammation, Glasgow Polyomics, University of Glasgow, Glasgow, G61 1QH, United Kingdom
| | - Tessa Moses
- EdinOmics, SynthSys - Centre for Synthetic and Systems Biology, School of Biological Sciences, The University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - Rónán Daly
- Institute of Infection, Immunity and Inflammation, Glasgow Polyomics, University of Glasgow, Glasgow, G61 1QH, United Kingdom
| | - S Alison Arnold
- Ingenza Ltd., Roslin Innovation Centre, Roslin, EH25 9RG, United Kingdom
| | - Karl Burgess
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Edinburgh, EH8 9AB, United Kingdom
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10
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Savizi ISP, Maghsoudi N, Motamedian E, Lewis NE, Shojaosadati SA. Valine feeding reduces ammonia production through rearrangement of metabolic fluxes in central carbon metabolism of CHO cells. Appl Microbiol Biotechnol 2022; 106:1113-1126. [PMID: 35044498 DOI: 10.1007/s00253-021-11755-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/21/2021] [Accepted: 12/27/2021] [Indexed: 11/02/2022]
Abstract
Ammonia is a toxic byproduct of CHO cell metabolism, which inhibits cell growth, reduces cell viability, alters glycosylation, and decreases recombinant protein productivity. In an attempt to minimize the ammonium accumulation in cell culture media, different amino acids were added individually to the culture medium before the production phase to alleviate the negative effects of ammonium on cell culture performance. Among all the amino acids examined in this study, valine showed the most positive impact on CHO cell culture performance. When the cultured CHO cells were fed with 5 mM valine, EPO titer was increased by 25% compared to the control medium, and ammonium and lactate production were decreased by 23 and 26%, respectively, relative to the control culture. Moreover, the sialic acid content of the EPO protein in valine-fed culture was higher than in the control culture, most likely because of the lower ammonium concentration. Flux balance analysis (FBA) results demonstrated that the citric acid cycle was enriched by valine feeding. The measurement of TCA cycle activity supported this finding. The analysis revealed that there might be a link between promoting tricarboxylic acid (TCA) cycle metabolism in valine-fed culture and reduction in lactate and ammonia accumulation. Furthermore, in valine-fed culture, FBA outcomes showed that alanine was excreted into the medium as the primary mechanism for reducing ammonium concentration. It was predicted that the elevated TCA cycle metabolism was concurrent with an increment in recombinant protein production. Taken together, our data demonstrate that valine addition could be an effective strategy for mitigating the negative impacts of ammonium and enhancing glycoprotein production in both quality and quantity. KEY POINTS: • Valine feeding can mitigate the negative impacts of ammonia on CHO cell growth. • Valine addition assists the ammonia removal mechanism by enriching the TCA cycle. • Ammonia is removed from the media through alanine excretion in valine-fed culture.
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Affiliation(s)
- Iman Shahidi Pour Savizi
- Biotechnology Department, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran
| | - Nader Maghsoudi
- Neuroscience Research Center, Shahid Beheshti University of Medical Science, Tehran, Iran
| | - Ehsan Motamedian
- Biotechnology Department, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran
| | - Nathan E Lewis
- Department of Bioengineering, University of California, La Jolla, San Diego, CA, USA.,School of Medicine, Novo Nordisk Foundation Center for Biosustainability at the University of California, La Jolla, San Diego, CA, USA.,Department of Pediatrics, School of Medicine, University of California, La Jolla, San Diego, CA, USA
| | - Seyed Abbas Shojaosadati
- Biotechnology Department, Faculty of Chemical Engineering, Tarbiat Modares University, P.O. Box 14155-4838, Tehran, Iran.
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