With increasing needs for high-value protein-based therapeutics, plant cells offer a safe and cost-effective alternative bioproduction platform. However, low protein productivity is a common bottleneck in the commercialization of this technology. This project engineers plant cells to express foreign proteins that are secreted into the cell culture medium. This is advantageous as the protein is now sequestered from intracellular proteolytic degradation and can be readily recovered and purified. Fundamental knowledge gained from this research will advance our understanding of plant development, stress defense, and plant cell wall assembly. This is a highly interdisciplinary research project that will present unique learning opportunities for both graduate and undergraduate students at Arkansas State University.
The overall goal of this project is to leverage a designer molecular carrier engineering technology in developing a commercially competitive plant cell-based bioproduction platform for high-value proteins. Specifically, this project aims to exploit the unique plant Hyp-O-glycosylation 'code' that precisely directs the O-glycosylation of a proline-rich peptide, to develop novel Hyp-O-glycosylated peptides (HypGPs) that function as a molecular carrier in excreting conjoined heterologous proteins to cell culture media. The PIs will test the hypothesis that strategically designed HypGP carriers can function to improve plant cell culture productivity by boosting the secretion of several model proteins and stabilizing these products in culture media. The precise Hyp-O-glycosylation process in tobacco BY-2 cells, and the key mechanisms facilitating protein secretion will be dissected. Based on the outcome of this study, optimal HypGP design in terms of peptide sequence and chain length to achieve the highest protein yields will be established. In order to assess the practical and broader applications of the designer HypGPs for expressing larger and complex therapeutic proteins, expression of two distinct and therapeutically promising proteins, human alfa1-antitrypsin (52 kDa) and interleukin-12 (70 kDa) will be tested. Additionally, broader applicability of Hyp-O-glycosylation 'code' to engineering functional designer HypGPs in monocot rice cell culture will be investigated towards advancing our understanding about the Hyp-O-glycosylation in monocot plants and achieving high protein productivity in rice cell culture. This award by the Biotechnology and Biochemical Engineering Program of the CBET Division is co-funded by the Systems and Synthetic Biology Program of the Division of Molecular and Cellular Biosciences and by the Experimental Program to Stimulate Competitive Research (EPSCoR).
