UNDERSTANDING THE ZINC INDUCED LACTATE SHIFT IN CHO CELL CULTURE AT TRANSCRIPTOMICS LEVEL TO IMPROVE THE PROTEIN PRODUCTION

摘要

Abstract: Mammalian cell culture plays a significant role in biopharmaceutical industry especially CHO cells are used in nearly 70% of all the recombinant protein production. Many recent advances in process development such as cell line development and media development have resulted in productivity enhancement. CHO cells respond to small changes in the culture such as trace metals. Few different trace metals were screened for their impact on cell culture performance. More than twice increase in protein titer was observed by the addition of zinc in cell culture at a particular level. Along with the titer increase, zinc also seems to prevent the lactate shift happening in the culture which is shown to have negative impact on cellular machinery efficiency as per literature. Understanding the reason for this lactate shift prevention by zinc at fundamental level can be potential target for cell line engineering in order to improve the productivity even higher by the addition of zinc. To understand this zinc induced prevention of lactate shift, RNA sequencing platform has been used for the differential gene expression between the two conditions. Messenger RNA from stationary phase were sequenced to find the gene expression responsible for causing the lactate behavior change induced by zinc. Exploration of global transcriptome exhibited the change in pathways regulation including acetyl CoA synthesis and usage, histone acetylation, mevalonate pathway, cholesterol synthesis, oxidative metabolism and apoptosis regulation. Also, the study reveals different genes involved in gluconeogenesis (PEP carboxykinase), metal and biotin transport (SLC5A6) that might be causing the impact on lactate behavior. These genes can be potential target for cell line engineering that can provide even higher titer after addition of specified zinc concentration.