Date of this Version
Ebea, P.O. (2019). Transport and Distribution of Bovine Milk Exosomes and miR-34a Cargo in Murine Cerebral Cortex Endothelial bEnd.3 Cells and BV2 Microglia. Master’s thesis, University of Nebraska-Lincoln.
The blood-brain barrier (BBB) poses an obstacle in the delivery of drugs to the brain. Bovine milk exosomes (BME) are explored for delivering antisense oligonucleotides to tumors, because BME are bioavailable and protect RNA cargos against degradation in the gastrointestinal tract. This study had the following objectives: 1) assess the transport kinetics of BME and their RNA cargos and secretion of RNA across the apical membrane in murine cerebral cortex endothelial bEnd.3 cells and 2) determine whether murine brain BV2 microglia have the potential to accumulate and, therefore, eliminate BME that crossed the BBB. The uptake of BME labeled with a lipophilic membrane dye followed Michaelis-Menten kinetics in bEnd.3 cells: Vmax = 0.77 ± 0.20 x 1011 BME/(10,000 cells x 45 min); Km = 1.8 ± 2.2 x 1011 BME/mL. Transport kinetics were similar in BV2 microglia compared to bEnd.3 cells. When BME were labeled with an RNA-reactive dye and uptake was analyzed by using Z-stack confocal microscopy, it was apparent that BME entered the cytoplasm of bEnd.3 cells. Studies of BME transfected with fluorophore-labeled miR-34a suggested that detectable amounts of miR-34a were transported from the apical into the basolateral compartment in dual chamber systems. We conclude that BME deserve further exploration for drug delivery across the BBB.
Advisor: Janos Zempleni