Biology subjects

Yang, R.-S.

Publications and source records attributed to Yang, R.-S..

3 recordsLinked to original sources

bioRxiv2025

Prolonged autophagy induction correlates with host cell protein reduction in CHO cell culture

Autophagy, a cellular recycling process regulated by the CLEAR signaling pathway, plays a pivotal role in maintaining cellular homeostasis. We hypothesize that this process may regulate and reduce HCP levels by targeting intracellular proteins and organelles for degradation. This study investigates the relationship between autophagy induction and the reduction of high-risk host cell proteins (HCPs), including polysorbate-degrading enzymes (PSDEs), to enhance the stability of therapeutic biologics such as monoclonal antibodies (mAbs). Using clonal analysis, we identified upregulation of the CLEAR pathway in one clone, correlating with a significant reduction in lipase activity and PSDE abundance. Furthermore, autophagy modulators, such as 3-methyladenine (3-MA), selectively decreased PSDE levels in both batch and fed-batch cultures. This resulted in 62% reduction in lipase activity that corresponded to a 22% improvement in polysorbate-80 stability. Additionally, 3-MA treatment increased mAb specific productivity and altered glycosylation profiles, increasing afucosylation and galactosylation levels. These findings highlight autophagy induction as a promising strategy to modulate product quality profiles and reduce high-risk HCPs in biologics production.

bioengineering↗

bioRxiv2025

Discovery of Chemical Tools for Polysorbate-Degradative Enzyme Control in Biopharmaceutical Upstream Process via Multi-Omic Profiling of Host Cell Clones

Host cell proteins are process-related impurities in biotherapeutics and can potentially pose risks to patient safety and product quality. Specifically, certain host cell-derived enzymes, including lipases, can degrade the formulation excipient polysorbate (PS) in biopharmaceutical formulations, affecting drug product stability in liquid formulations. We leveraged multi-omics approaches, including transcriptomics, proteomics, and activity-based protein profiling (ABPP), to identify mechanisms that regulate PS-degradative enzyme (PSDE) abundance and to develop strategies for their control. Comparative multiomics analysis of two monoclonal antibodies (mAb)-producing host cell clones revealed differential lipase profiles at the mRNA, protein, and enzyme activity levels and associated increased lipase activity with upregulated lipid catabolic pathways such as the fatty acid beta oxidation pathway. Further, for the first time in the literature, we identified peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}) as a key regulator of PSDEs in manufacturing Chinese Hamster Ovary (CHO) cells. Downregulation of the PPAR{gamma} pathway with its antagonists resulted in selective reduction of PSDE levels and improved PS stability without compromising mAb productivity or quality. This study highlights the potential of PPAR{gamma} modulators as chemical tools for PSDE control at the gene regulation level, offering significant implications for biopharmaceutical process development and control.

bioengineering↗

bioRxiv2020

Profiling Active Enzymes for Polysorbate Degradation in Biotherapeutics by Activity-Based Protein Profiling

Polysorbate is widely used to maintain stability of biotherapeutic proteins in formulation development. Degradation of polysorbate can lead to particle formation in drug products, which is a major quality concern and potential patient risk factor. Enzymatic activity from residual enzymes such as lipases and esterases can cause polysorbate degradation. Their high activity, even at low concentration, constitutes a major analytical challenge. In this study, we evaluated and optimized the activity-based protein profiling (ABPP) approach to identify active enzymes responsible for polysorbate degradation. Using chemical probes to enrich active serine hydrolases, more than 80 proteins were identified in harvested cell culture fluid (HCCF) from monoclonal antibodies (mAb) production. A total of 8 known lipases were identified by ABPP, while only 5 lipases were identified by a traditional abundance-based proteomics (TABP) approach. Interestingly, phospholipase B-like 2 (PLBL2), a well-known problematic HCP was not found to be active in process-intermediates from two different mAbs. In a proof-of-concept study, phospholipase A2 group VII (PLA2G7) and sialic acid acetylesterase (SIAE) were identified by ABPP as possible root causes of polysorbate-80 degradation. The established ABBP approach can fill the gap between lipase abundance and activity, which enables more meaningful polysorbate degradation investigations for biotherapeutic development.

bioengineering↗