SYSTEMATIC STEM CELL BIOPROCESS ENGINEERING

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Bioprocess engineering has played a transformative role in enabling discoveries in molecular biology and recombinant DNA technologies, ultimately yielding new therapeutics – monoclonal antibodies and vaccines. Building on Canadian strengths in stem cell biology, bioprocess engineering of cell-based therapies represents a next wave in the development of biologics to treat or cure disease. Whether or not these products ever reach patients depends upon technologies to manufacture cells in a robust and cost effective manner. Stem cells play an important role as the “raw material” in manufacturing cell therapies, analogous to E. coli and hybridoma cells as the workhorses of the biopharmaceutical industry. The fact that the product is living cells, not their isolated and enriched protein products, brings forward a different set of manufacturing and control challenges. Bioengineering fundamentals including bioreactor design, metabolic modeling and process control need to be combined with systems biology principles to guide the development of innovative technologies for manufacturing cell based products. The overall goal of this research program is to develop a mechanism-based platform for cell therapy manufacturing, focusing on two novel and interrelated projects: A) Integrating metabolic modeling and control into pluripotent stem cell bioprocesses. Understanding and controlling cell metabolism has played an important role in biopharmaceutical production and evidence suggests that cell therapies will similarly benefit from an increased understanding of metabolic networks in cell output optimization. Induced pluripotent stem cells (iPSC), cells generatable from any nucleated cell type via so-called reprogramming, are a powerful model with which to study the role of metabolism in cell production. In this project we specifically aim to develop computational models of the iPSC metabolic network during reprogramming, test the influence of key model control points on reprograming frequencies, and optimize metabolic control parameters in iPSC bioprocesses to increase cell yields. B) Automated secreted-factor feedback-controlled bioreactors for enhanced stem cell propagation. Process control strategies in biopharmaceutical production typically rely on the relatively stable and homogenous responses of transformed cells or microbes to culture set-points to optimize recombinant protein yield. In contrast, cell therapy production involves heterogeneous cell populations where competing growth rates and culture requirements yield continuously changing and often unstable cultures. Our NSERC research has demonstrated that endogenous soluble factor-mediated feedback inhibition represents a dominant control point in primary blood stem cell culture outputs. In this project we will undertake the development and validation of bioreactor systems based on real-time and dynamic control of endogenously produced signaling factors. This project will not only yield new strategies to achieve robust control in cell therapy manufacturing, but also fundamental information on feedback control of primary cell systems. Overall, by utilizing engineering-based approaches such mathematical modeling and bioreactor design, the proposed research program should allow the development of technologies that enable the emerging Canadian cell therapy industry. The proposed work will also support the continued training of personnel ideally suited to contribute to high value next-generation industrial biotechnology manufacturing processes.