04/01/2021
By Sokny Long

The Francis College of Engineering, Department of Chemical Engineering invites you to attend a doctoral dissertation defense by Bingyu Kuang on “Metabolic By-product Identification, Pathway Analysis and Control through Metabolomics Study in CHO Cell Culture."

Defense Date: Thursday, April 15, 2021
Time: 11:15 a.m. - 1:15 p.m. EST
Location: This will be a virtual defense via Zoom. Those interested in attending should contact Bingyu_Kuang@student.uml.edu and committee advisor Seongkyu_Yoon@uml.edu at least 24 hours prior to the defense to request access to the meeting.

Committee Chair (Advisor): Seongkyu Yoon, Ph.D., Professor, Department of Chemical Engineering, University of Massachusetts Lowell

Committee Members:

  • Dongming Xie, Ph.D., Associate Professor, Department of Chemical Engineering, University of Massachusetts Lowell
  • HsiWu Wong, Ph.D., Assistant Professor, Department of Chemical Engineering, University of Massachusetts Lowell
  • Scott Shaffer, Ph.D., Professor, Chemistry, UMass Medical School
  • Kyongbum Lee, Ph.D., Professor, Chemical and Biological Engineering, Tufts University
  • Wai Lam Ling, Ph.D., Sr. Director, Rocket Pharmaceuticals

Abstract:
Mammalian cells tend to consume as much as nutrients available and boost cell metabolism, which can cause metabolism disorders. Chinese Hamster Ovary (CHO) cells, the mammalian model used in this study, are the main workhorse of therapeutic proteins production, reached market value over $200 billion. CHO cells will often consume the available nutrients in order to support growth and key cell functions. However, inefficiencies in mammalian metabolism can lead to extracellular accumulation of waste metabolites and by-products, which in turn can inhibit proliferation and negatively impact protein synthesis. In this study, an LCMS-based metabolomics pipeline was utilized to screen CHO cellular metabolites accumulating in the cell supernatants. A total of eight metabolites produced through CHO cells metabolism were identified and characterized, six of which have not been reported previously to have been secreted by CHO cells. When supplemented back into a fed-batch culture, significant reduction in cellular growth was observed in the presence of each metabolite and all the identified metabolites were shown to impact the glycosylation of a model secreted antibody, with seven of these also reducing its productivity and all eight inhibiting the formation of mono-galactosylated biantennary (G1F) and biantennary galactosylated (G2F) N-glycans.  In-depth pathway analysis revealed that these metabolites are produced when cells utilize major energy sources such as glucose and select amino acids (tryptophan, arginine, isoleucine and leucine) for growth, maintenance and protein production. Furthermore, these novel inhibitory metabolites were observed to accumulate in multiple CHO cell lines (CHO-K1 and CHO-GS) as well as the human HEK293 cell line. The flux balance analysis (FBA) was constructed using CHO genome-scale model to simulate the optimized composition of the nutrients and the critical genes guiding the efficient cell metabolism, which can mitigate the inhibitory metabolites accumulation and promote cell growth. The biological validation of the optimized process shown 40-60% higher viable cell density and the extend the growth phase. The inhibitory metabolites and NH4+ accumulation were mitigated ranging from 20-80%. This study provides a robust and holistic methodology to incorporate global metabolomic analysis into cell culture studies for identification and control the novel metabolites that participate in key metabolic pathways inhibitory to growth, productivity and post-translational processing.

All interested students and faculty members are invited to attend the online defense via remote access.