Agitation in a Microcarrier-Based Spinner Flask Bioreactor Modulates Homeostasis of Human Mesenchymal Stem Cells

Human Mesenchymal Stem Cells (hMSCs) are well known in cell therapy due to their secretion of trophic factors, multipotent differentiation potential, and ability for self-renewal. As a result, the number of clinical trials has been steadily increasing over the last decade highlighting the need for in vitro systems capable of producing large quantities of cells to meet growing demands. However, hMSCs are highly sensitive to microenvironment conditions, including shear stress caused by dynamic bioreactor systems, and can lead to alteration of cellular homeostasis. In this study, we demonstrate a 3-fold expansion of hMSCs within a 125 mL spinner flask bioreactor system. Furthermore, we show culturing in this dynamic environment (compared to conventional 2D planar culture) results in hMSCs exhibiting higher total levels of reactive oxidative species (ROS), as well as known ROS regulator Sirtuin-3, having implications on the nicotinamide adenine dinucleotide (NAD+) metabolic pathway and metabolic homeostasis. In addition, added stress from culturing in this dynamic microenvironment increased Prostaglandin E₂ (PGE2) secretion as well as reduced the potential for Indoleamine-pyrrole 2,3-dioxygenase (IDO) secretion upon stimulus with interferon gamma (IFNγ). The results of this study have implications on engineering strategies for scalable production of hMSCs utilized in clinical trials and biomanufacturing.