GLUCOCORTICOID CELL PRIMING ENHANCES NONVIRAL GENE DELIVERY TO HUMAN MESENCHYMAL STEM CELLS

Safe and efficient gene delivery to human mesenchymal stem cells (hMSCs) is vital for their clinical effectiveness, yet non-viral gene delivery, which is considered safer than viral delivery, remains comparably inefficient. Glucocorticoids (GCs), when conjugated to a polymeric vector, have been shown to increase nonviral gene delivery to human liver carcinoma and rat cardiomyocytes, and maintain the stemness of hMSCs when added to cell media. Here, GCs, dexamethasone and cortisol, were shown to significantly enhance nonviral gene delivery to hMSCs, demonstrated by an increase in transfection efficiency (3 to 3.5-fold enhancement), transgene expression (8 to 13-fold enhancement), and prolonged transgene expression when compared to gene delivery without GCs. These results were consistent across four cell donors using the most common nonviral delivery vehicles: Lipofectamine 2000 and LTX, and polyethylenimine. The effects of GCs on transfection were shown to be dependent on GC receptor binding and caused in part by the maintenance of normal hMSC metabolic activity and an increase in cellular DNA uptake, 3 to 6-fold over cells without GCs. These results demonstrate the simplicity and effectiveness of GC priming to enhance transfection in hMSCs across multiple donors. Additional evaluation of the mechanisms responsible for the GC-mediated transfection enhancement will serve to identify new cell targets for GC priming and mechanisms for perturbation in unresponsive cell types, which could ultimately lead to the creation of a universally applicable cell priming protocol for enhancing nonviral gene delivery to all cell types. Advisor: Angela K. Pannie