1
|
Lu YA, Brien CMO, Mashek DG, Hu WS, Zhang Q. Kinetic-model-based pathway optimization with application to reverse glycolysis in mammalian cells. Biotechnol Bioeng 2023; 120:216-229. [PMID: 36184902 DOI: 10.1002/bit.28249] [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: 07/09/2022] [Revised: 09/19/2022] [Accepted: 09/28/2022] [Indexed: 12/13/2022]
Abstract
Over the last two decades, model-based metabolic pathway optimization tools have been developed for the design of microorganisms to produce desired metabolites. However, few have considered more complex cellular systems such as mammalian cells, which requires the use of nonlinear kinetic models to capture the effects of concentration changes and cross-regulatory interactions. In this study, we develop a new two-stage pathway optimization framework based on kinetic models that incorporate detailed kinetics and regulation information. In Stage 1, a set of optimization problems are solved to identify and rank the enzymes that contribute the most to achieving the metabolic objective. Stage 2 then determines the optimal enzyme interventions for specified desired numbers of enzyme adjustments. It also incorporates multi-scenario optimization, which allows the simultaneous consideration of multiple physiological conditions. We apply the proposed framework to find enzyme adjustments that enable a reverse glucose flow in cultured mammalian cells, thereby eliminating the need for glucose feed in the late culture stage and enhancing process robustness. The computational results demonstrate the efficacy of the proposed approach; it not only captures the important regulations and key enzymes for reverse glycolysis but also identifies differences and commonalities in the metabolic requirements for different carbon sources.
Collapse
Affiliation(s)
- Yen-An Lu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Conor M O' Brien
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Douglas G Mashek
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Wei-Shou Hu
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA
| | - Qi Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota, USA
| |
Collapse
|
2
|
Vappiani J, Eyster T, Orzechowski K, Ritz D, Patel P, Sévin D, Aon J. Exometabolome profiling reveals activation of the carnitine buffering pathway in fed-batch cultures of CHO cells co-fed with glucose and lactic acid. Biotechnol Prog 2021; 37:e3198. [PMID: 34328709 DOI: 10.1002/btpr.3198] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 07/22/2021] [Accepted: 07/26/2021] [Indexed: 11/06/2022]
Abstract
Adjustments to CHO cell physiology were recently observed during implementation of a Raman spectroscopy-based glucose and lactate control strategy. To further understand how these cells, under monoclonal antibody (mAb) production conditions, utilized the extra lactic acid fed, we performed a comprehensive semi-quantitative and time-dependent analysis of the exometabolome. This study focused on the CHO cell's metabolic shift from the fifth day of culture. We compared relative levels of extracellular metabolites in the absence or presence of a 2 g/L lactic acid setpoint while glucose was kept at 4 g/L. Our hypothesis is that extra lactic acid would supply more pyruvate, favoring oxidative phosphorylation. We subsequentially uncovered several carnitine derivatives as biomarkers of the simultaneous activation of TCA anaplerotic pathways as well as a carbon-buffering pathway. CHO cells exhibited a balance between intermediates from (i) amino acid catabolism, (ii) fatty acid β-oxidation, and (iii) pyruvate from glycolysis and lactic acid; and the secretion of their intermediate carnitine derivatives. In addition, 3-hydroxy-methyl-glutaric acid (HMG) and mevalonate syntheses were found as biomarkers of alternative acyl group removal. Together, under a limited capacity to assimilate the surplus of acyl-CoA groups as well as an ability to maintain the acyl-CoA: free CoA ratio for proper and continuous functioning of the TCA cycle, CHO cells activate the carnitine-buffering system, HMG, and mevalonate pathways.
Collapse
Affiliation(s)
| | - Tom Eyster
- Microbial & Cell Culture Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Keegan Orzechowski
- Microbial & Cell Culture Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Diana Ritz
- Microbial & Cell Culture Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Pramthesh Patel
- Microbial & Cell Culture Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| | - Daniel Sévin
- Cellzome GmbH, GlaxoSmithKline, Heidelberg, Germany
| | - Juan Aon
- Microbial & Cell Culture Development, GlaxoSmithKline, King of Prussia, Pennsylvania, USA
| |
Collapse
|
3
|
Kapuy O, Makk-Merczel K, Szarka A. Therapeutic Approach of KRAS Mutant Tumours by the Combination of Pharmacologic Ascorbate and Chloroquine. Biomolecules 2021; 11:652. [PMID: 33925206 PMCID: PMC8146763 DOI: 10.3390/biom11050652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/24/2021] [Accepted: 04/26/2021] [Indexed: 12/12/2022] Open
Abstract
The Warburg effect has been considered a potential therapeutic target to fight against cancer progression. In KRAS mutant cells, PKM2 (pyruvate kinase isozyme M2) is hyper-activated, and it induces GLUT1 expression; therefore, KRAS has been closely involved in the initiation of Warburg metabolism. Although mTOR (mammalian target of rapamycin), a well-known inhibitor of autophagy-dependent survival in physiological conditions, is also activated in KRAS mutants, many recent studies have revealed that autophagy becomes hyper-active in KRAS mutant cancer cells. In the present study, a mathematical model was built containing the main elements of the regulatory network in KRAS mutant cancer cells to explore the further possible therapeutic strategies. Our dynamical analysis suggests that the downregulation of KRAS, mTOR and autophagy are crucial in anti-cancer therapy. PKM2 has been assumed to be the key switch in the stress response mechanism. We predicted that the addition of both pharmacologic ascorbate and chloroquine is able to block both KRAS and mTOR pathways: in this case, no GLUT1 expression is observed, meanwhile autophagy, essential for KRAS mutant cancer cells, is blocked. Corresponding to our system biological analysis, this combined pharmacologic ascorbate and chloroquine treatment in KRAS mutant cancers might be a therapeutic approach in anti-cancer therapies.
Collapse
Affiliation(s)
- Orsolya Kapuy
- Department of Molecular Biology, Institute of Biochemistry and Molecular Biology, Semmelweis University, H-1428 Budapest, Hungary;
| | - Kinga Makk-Merczel
- Laboratory of Biochemistry and Molecular Biology, Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, H-1111 Budapest, Hungary;
- Biotechnology Model Laboratory, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
| | - András Szarka
- Department of Molecular Biology, Institute of Biochemistry and Molecular Biology, Semmelweis University, H-1428 Budapest, Hungary;
- Laboratory of Biochemistry and Molecular Biology, Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, H-1111 Budapest, Hungary;
- Biotechnology Model Laboratory, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Szent Gellért tér 4, H-1111 Budapest, Hungary
| |
Collapse
|
4
|
O'Brien CM, Zhang Q, Daoutidis P, Hu WS. A hybrid mechanistic-empirical model for in silico mammalian cell bioprocess simulation. Metab Eng 2021; 66:31-40. [PMID: 33813033 DOI: 10.1016/j.ymben.2021.03.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 01/10/2021] [Accepted: 03/27/2021] [Indexed: 12/20/2022]
Abstract
In cell culture processes cell growth and metabolism drive changes in the chemical environment of the culture. These environmental changes elicit reactor control actions, cell growth response, and are sensed by cell signaling pathways that influence metabolism. The interplay of these forces shapes the culture dynamics through different stages of cell cultivation and the outcome greatly affects process productivity, product quality, and robustness. Developing a systems model that describes the interactions of those major players in the cell culture system can lead to better process understanding and enhance process robustness. Here we report the construction of a hybrid mechanistic-empirical bioprocess model which integrates a mechanistic metabolic model with subcomponent models for cell growth, signaling regulation, and the bioreactor environment for in silico exploration of process scenarios. Model parameters were optimized by fitting to a dataset of cell culture manufacturing process which exhibits variability in metabolism and productivity. The model fitting process was broken into multiple steps to mitigate the substantial numerical challenges related to the first-principles model components. The optimized model captured the dynamics of metabolism and the variability of the process runs with different kinetic profiles and productivity. The variability of the process was attributed in part to the metabolic state of cell inoculum. The model was then used to identify potential mitigation strategies to reduce process variability by altering the initial process conditions as well as to explore the effect of changing CO2 removal capacity in different bioreactor scales on process performance. By incorporating a mechanistic model of cell metabolism and appropriately fitting it to a large dataset, the hybrid model can describe the different metabolic phases in culture and the variability in manufacturing runs. This approach of employing a hybrid model has the potential to greatly facilitate process development and reactor scaling.
Collapse
Affiliation(s)
- Conor M O'Brien
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455-0132, USA
| | - Qi Zhang
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455-0132, USA
| | - Prodromos Daoutidis
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455-0132, USA
| | - Wei-Shou Hu
- Department of Chemical Engineering and Materials Science, University of Minnesota, 421 Washington Avenue SE, Minneapolis, MN, 55455-0132, USA.
| |
Collapse
|
5
|
van Rosmalen RP, Smith RW, Martins Dos Santos VAP, Fleck C, Suarez-Diez M. Model reduction of genome-scale metabolic models as a basis for targeted kinetic models. Metab Eng 2021; 64:74-84. [PMID: 33486094 DOI: 10.1016/j.ymben.2021.01.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 01/05/2021] [Accepted: 01/15/2021] [Indexed: 11/26/2022]
Abstract
Constraint-based, genome-scale metabolic models are an essential tool to guide metabolic engineering. However, they lack the detail and time dimension that kinetic models with enzyme dynamics offer. Model reduction can be used to bridge the gap between the two methods and allow for the integration of kinetic models into the Design-Built-Test-Learn cycle. Here we show that these reduced size models can be representative of the dynamics of the original model and demonstrate the automated generation and parameterisation of such models. Using these minimal models of metabolism could allow for further exploration of dynamic responses in metabolic networks.
Collapse
Affiliation(s)
- R P van Rosmalen
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, Wageningen, the Netherlands
| | - R W Smith
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, Wageningen, the Netherlands
| | - V A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, Wageningen, the Netherlands; Lifeglimmer GmbH, Berlin, Germany
| | - C Fleck
- Freiburg Center for Data Analysis and Modelling University of Freiburg Freiburg Germany; Control Theory and Systems Biology Laboratory, Department of Biosystems Science and En- gineering, ETH Zürich, Basel, Switzerland
| | - M Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Department of Agrotechnology and Food Sciences, Wageningen University & Research, Wageningen, the Netherlands.
| |
Collapse
|
6
|
O’Brien SA, Hu WS. Cell culture bioprocessing - the road taken and the path forward. Curr Opin Chem Eng 2020; 30:100663. [PMID: 33391982 PMCID: PMC7773285 DOI: 10.1016/j.coche.2020.100663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Cell culture processes are used to produce the vast majority of protein therapeutics, valued at over US$180 billion per annum worldwide. For more than a decade now, these processes have become highly productive. To further enhance capital efficiency, there has been an increase in the adoption of disposable apparatus and continuous processing, as well as a greater exploration of in-line sensing, various -omic tools, and cell engineering to enhance process controllability and product quality consistency. These feats in cell culture processing for protein biologics will help accelerate the bioprocess advancements for virus and cell therapy applications.
Collapse
Affiliation(s)
- Sofie A. O’Brien
- Department of Biomedical Engineering and Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| | - Wei-Shou Hu
- Department of Biomedical Engineering and Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, MN 55455-0132 USA
| |
Collapse
|
7
|
Gopalakrishnan S, Dash S, Maranas C. K-FIT: An accelerated kinetic parameterization algorithm using steady-state fluxomic data. Metab Eng 2020; 61:197-205. [DOI: 10.1016/j.ymben.2020.03.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/31/2020] [Accepted: 03/02/2020] [Indexed: 12/12/2022]
|
8
|
Abstract
Following the success of and the high demand for recombinant protein-based therapeutics during the last 25 years, the pharmaceutical industry has invested significantly in the development of novel treatments based on biologics. Mammalian cells are the major production systems for these complex biopharmaceuticals, with Chinese hamster ovary (CHO) cell lines as the most important players. Over the years, various engineering strategies and modeling approaches have been used to improve microbial production platforms, such as bacteria and yeasts, as well as to create pre-optimized chassis host strains. However, the complexity of mammalian cells curtailed the optimization of these host cells by metabolic engineering. Most of the improvements of titer and productivity were achieved by media optimization and large-scale screening of producer clones. The advances made in recent years now open the door to again consider the potential application of systems biology approaches and metabolic engineering also to CHO. The availability of a reference genome sequence, genome-scale metabolic models and the growing number of various “omics” datasets can help overcome the complexity of CHO cells and support design strategies to boost their production performance. Modular design approaches applied to engineer industrially relevant cell lines have evolved to reduce the time and effort needed for the generation of new producer cells and to allow the achievement of desired product titers and quality. Nevertheless, important steps to enable the design of a chassis platform similar to those in use in the microbial world are still missing. In this review, we highlight the importance of mammalian cellular platforms for the production of biopharmaceuticals and compare them to microbial platforms, with an emphasis on describing novel approaches and discussing still open questions that need to be resolved to reach the objective of designing enhanced modular chassis CHO cell lines.
Collapse
|