Multi‐Omics Study on the Impact of Cysteine Feed Level on Cell Viability and mAb Production in a CHO Bioprocess

Abstract

There is continual demand to maximize CHO cell culture productivity of a biotherapeutic while maintaining product quality. In this study, a comprehensive multi‐omics analysis is performed to investigate the cellular response to the level of dosing of the amino acid cysteine (Cys) in the production of a monoclonal antibody (mAb). When Cys feed levels are insufficient, there is a significant decrease in protein titer. Multi‐omics (metabolomics and proteomics, with support from RNAseq) is performed over the time course of the CHO bioprocess producing an IgG1 mAb in 5 L bioreactors. Pathway analysis reveals that insufficient levels of Cys in the feed lead to Cys depletion in the cell. This depletion negatively impacts antioxidant molecules, such as glutathione (GSH) and taurine, leading to oxidative stress with multiple deleterious cellular effects. In this paper, the resultant ER stress and subsequent apoptosis that affects cell viability and viable cell density has been considered. Key metabolic enzymes and metabolites are identified that can be potentially monitored as the process progresses and/or increased in the cell either by nutrient feeding or genetic engineering. This work reinforces the centrality of redox balance to cellular health and success of the bioprocess as well as the power of multi‐omics to provide an in‐depth understanding of the CHO cell biology during biopharmaceutical production.

Towards robust cell culture processes — Unraveling the impact of media preparation by spectroscopic online monitoring

“…Tyrosine is a fluorescent molecule and therefore variants of this amino acids directly affect the fluorescent signals. Taurine can play an important role for antioxidant processes in cell cultivations . It is capable of building stable complexes with Cu 2+ and therefore might affect tryptophan fluorescence in a similar way as described for methionine .…”

“…Through the coded factors out of the DoE it could be revealed that the derived, cell line dependent, models for specific lactate production q lac (cell line B), product titer (cell line A), and average specific cell growth µ average (cell line A) were mostly affected by the storage time and not by the preparation parameters of the P‐media. Although strong effects on the chemical media composition could be observed already after the media preparation processes (Table ) and the fact that several compounds have been reported before to have an impact on cell culture performance , potential effects of the media preparation parameters might have been masked by media storage or media equilibration conditions prior to inoculation. The impact of variable F‐media preparation parameters on process performance was negligible.…”

“…that several compounds have been reported before to have an impact on cell culture performance [40,41,48], potential effects of the media preparation parameters might have been masked by media storage or media equilibration conditions prior to inoculation. The impact of variable F-media preparation parameters on process performance was negligible.…”

Recent Developments in Bioprocessing of Recombinant Proteins: Expression Hosts and Process Development

“…A simple technique was also developed to screen multiple CHO cell clones for cell growth rate and protein production (Beketova et al, 2019). Additionally, a multi-omics study was carried out on the impact of cysteine feed level on cell viability and IgG 1 mAb production in 5 l bioreactors using CHO cells so as to obtain an in-depth understanding of the CHO cell biology (Ali et al, 2019). In a recent study, CHO cells were engineered with synthetic genetic circuits to tune the N-glycosylation of a stably expressed IgG (Chang et al, 2019).…”

Characterization of glutathione proteome in CHO cells and its relationship with productivity and cholesterol synthesis.

“…In a recent study, it was shown that a decrease of cysteine supply led to a depletion of glutathione (Ali et al, 2019). As a consequence, the oxidative stress generated led to cell death, titer decrease and differential expression of proteins.…”