(511f) Carnitine Derivatives Reveal Mitochondrial Dysfunction in Two Distinctly Performing CHO Cell Cultures Co-Fed with Glucose and Lactic Acid

Metabolomics analysis of cell culture processes can provide valuable insight into cellular physiology that can be leveraged to develop more robust and productive processes. In this work, we applied metabolomics to interrogate CHO cell behavior in two different chemically-defined media formulations in cultures co-fed with glucose and lactic acid. We previously reported carnitine derivatives are clear biomarkers of altered metabolism when cultures are fed lactic acid. Acylcarnitines cannot simply be considered byproducts of the carnitine transfer system but also indicate altered mitochondrial metabolism. Considering the extracellular metabolite profiles in cultures supplied lactic acid as a direct source of pyruvic acid and so of acetyl-CoA, we found a larger secretion of certain carnitine derivatives in medium A compared to medium B. Medium B supports better functioning of the TCA cycle by increasing the capacity to process the additional acetyl-CoA provided by co-feeding lactic acid. Homeostasis between acetyl-CoA/CoA and acetyl-CoA/carnitine is based on the export of acylcarnitines via the carnitine buffering system. Furthermore, when cells were grown in medium B, increased cell growth and antibody production were observed than in medium A. To interpret the data, we focused on selected media components which were considered crucial for the proper functioning of the TCA cycle and pathways predominantly required for mAb production. Improved functioning of the TCA cycle was revealed in the differentially utilized vitamins between media. As co-factors of key dehydrogenases, they appear highly consumed in medium B correlating with a better functioning of the TCA leading to better growth and productivity.