(340ae) Analyzing and Manipulating Endoplasmic Reticulum Stress and the Unfolded Protein Response across Various Cell Types

My research experience focuses on analyzing and engineering proteins, protein secretion, and ER stress across cell types, with a specialization in mammalian cells. As an undergraduate, I worked to measure enzyme activity of a Polymer Conjugated Enzyme (PCE) system designed to assist in metabolizing liver toxins in vivo. Early in my graduate career, I worked on projects focused on characterizing and engineering various yeast species for growth in ionic liquids and expression of lignin-degrading enzymes. These experiences jumpstarted my interests in genetic and protein engineering and therapeutic drug development and delivery. My dissertation work followed suit with characterizing the events and subsequent signaling leading to Chinese hamster ovary (CHO) cells undergoing stress during biomanufacturing. These host cells are the most common protein production platforms due to efficient post-translational modification machinery and endoplasmic reticulum (ER) quality control. However, high titers of recombinant proteins pose a burden and lead to an imbalance in ER homeostasis. Cell stress, as a result, can have a significant impact on productivity, product titer, and product quality, which are all of particular importance in production of therapeutics and pharmaceuticals. Accumulation of improperly folded proteins in the ER initiates the unfolded protein response (UPR) to restore ER homeostasis. My work has focused on understanding the dynamics of the UPR in CHO cell lines producing distinct protein products, with the aim to manipulate this signaling response for improving recombinant protein production. The research has given me experience with a wide-variety of techniques, including transcriptomic analysis, and I have been able to model the transient nature of the UPR in different CHO cell lines as well as identify new targets which are hypothesized to enhance protein folding.

Research Interests

Despite the negative connotation of ER stress, the UPR results in increased expression of multiple chaperones, and review of the literature, including my research, suggests highly productive CHO cell lines exhibit increased mRNA and protein levels of ER stress markers. Therefore, I hypothesize CHO cell genomic integration sites can be associated with a high productivity phenotype based on the extent of subsequent ER stress and UPR activation. This could have tremendous impacts for improving efficacious development of stable CHO cell lines. I would also like to extend this rationale to yeast species, since the UPR is a somewhat conserved mechanism in yeast, and these species have relevance in industrial production of a wide-range of products, including therapeutics. It would also be interesting to engineer yeast species to express mammalian chaperones in an attempt to improve protein folding in a host cell platform with more rapid and cheaper growth than CHO cells. My research has progressed through interpreting the results of similar studies involving various cell types such as HeLa cells, HEK293 cells, cancer cells, and various disease models such as prion disease, Parkinson disease, and Alzheimer’s disease. Additionally, many cell and tissue types apply the UPR in a distinct manner. I would like to expand my research to study ER stress and the UPR in other cell types and disease models which could have implications in multiple sectors, including the industrial and biomedical fields.