Advisors

Johnna Temenoff, PhD (Georgia Institute of Technology)

Robert Guldberg, PhD (University of Oregon)

Committee

Nick Willett, PhD (University of Oregon)

Levi Wood, PhD (Georgia Institute of Technology)

Christopher Evans, PhD (Mayo Clinic)

Title: Culture Systems for controlling mesenchymal stromal cell, protein, and cell-secreted protein release

Abstract: Mesenchymal stromal cells (MSCs) are highly-secretory cells that are of great clinical interest, due to their immunomodulatory and pro-regenerative properties when transplanted in vivo. Despite their clinical potential, current methods commonly used for MSC culture are unsuitable for their production as secretory cell therapies at clinical- or commercial scales. Furthermore, their development has been limited by a poor understanding of mechanisms regulating MSC secretory and therapeutic function. Comprehensive investigation of different conditioning strategies and culture systems is needed to identify those critical to improving the production of MSCs and MSC-secreted factors. Doing so may also reveal key cellular processes controlling therapeutic factor release, which may be further leveraged to improve MSC potency.

The long-term goal of this thesis was to develop culture systems for better understanding and controlling the release of cells, proteins, and cell-secreted proteins towards improved MSC scaling and, ultimately, potency as a therapeutic product. First, multiomics characterization of MSCs cultured in monolayer and as aggregates was performed to evaluate changes to cell physiology corresponding with enhanced secretory activity. Additionally, MSCs were cultured on hydrogel substrates with different mechanical and biochemical properties to determine those most important for controlling MSC proliferation and secretion. Next, one critical culture substrate property (stiffness) was utilized to develop microcarriers for improving secretion by genetically-modified MSCs. Lastly, a novel culture substrate responsive to Factor Xa was developed for on-demand release of MSCs from culture, as well as for the release of proteins for therapeutic applications. Overall, this work provides strategies for better interrogating and improving MSC bioactive factor release, which may be used to further develop highly efficacious MSC-based therapies, as well as other therapies that rely on responsive release of bioactive agents.