Dynamic metabolic modeling of CHO cell metabolism coupled with N-glycosylation in the industrial pharmaceutical production

Cellular metabolism consists of a complex network of biochemical reactions and thus presents a challenging modeling problem. Experimental and modeling work, described in this article is focused on the metabolic pathway of Chinese hamster ovary (CHO) cells, which are the preferred expression system for monoclonal antibody (mAb) protein production. CHO cells are one of the primary hosts for mAbs production, which have extensive applications in multiple fields like biochemistry, biology and medicine. Here, an approach to explain cellular metabolism with in-silico modeling of a microkinetic reaction network is presented and validated with unique experimental results. Experimental data of 25 different fed-batch bioprocesses included the variation of multiple process parameters, such as pH, agitation speed, oxygen and carbon dioxide content, and dissolved oxygen. 151 metabolites were involved in our proposed metabolic network, which consisted of 132 chemical reactions that describe the reaction pathways, and include 25 reactions describing N-glycosylation and additional reactions for the accumulation of the produced glycoforms. Additional 8 reactions are considered for accumulation of the N-glycosylation products in the extracellular environment and 1 reaction to correlate cell degradation. The following pathways were considered: glycolysis, pentose phosphate pathway, nucleotide synthesis, tricarboxylic acid cycle, lipid synthesis, protein synthesis, biomass production, anaplerotic reactions and membrane transport. Our contribution to this field is the comparison of unique experimental data to our model, which is coupled with biomass production and N-glycosylation. The effect of various operational conditions was assessed and their effect on the cell production process. The modeling performed is a complementary tool to experimentation, nevertheless, with the applied modeling procedure, different operational scenarios and fed-batch techniques can be tested without the need for long-term experimental campaigns.