In the context of NanoStem Project, a Marie-Curie Innovative Training Network project funded by the European Union’s Horizon 2020, and in collaboration with HCS Pharma, Elisa L.J. Moya defensed successfully her PhD the 15th December 2021 in Université d’Artois (Lens, France) about the miniaturization and automation of a well-established human in vitro BBB model, and the use of these models to evaluate the mechanisms of transport of nanoparticles.
Central nervous system (CNS) diseases are one of the top death causes worldwide, being a heavy burden for health care systems. CNS drug treatment is limited, because of the difficulty of drug penetration into the brain due to the BBB located at the brain capillary endothelial cells. Thus, many promising CNS drugs fail in clinical trials. Hence, there is a need to develop effective CNS drugs considering their ability to reach the brain. In order to avoid the many failures in the clinical phase, it is important to select them early during drug development. The use of in vitro BBB models has proved useful as a valuable tool to evaluate the impact of drugs/compounds toxicity, BBB permeation rates, cellular and molecular transport mechanisms within the brain cells as well as new strategies to bypass the BBB. However, these studies are time-consuming, require valuable and costly materials (animal brains, human cells, cell culture medium, sera…) and plastic-wastes in large quantity due to the format of the models.
The project developed during her PhD had two main objectives:
– Adapt a human in vitro BBB model to a higher screening capacity by miniaturizing and automating it.
– Study, using these human in vitro BBB models, the interactions of surfactant coated PLGA (Polylactide-co-glycolide) nanoparticles (NP) with human brain endothelial cells.
Based on a patented and well-established human in vitro BBB model, a miniaturized and automated replicate using 96-Multiwell system format has been developed. This model replicate has met the expected criteria reproducing the in vivo properties of a brain endothelium with presence of tight junctions and low paracellular permeability, as well as functionality of efflux pumps and membrane receptors. This model presents a high correlation with human in vivo data concerning the brain exposure to the drugs. Hence, this miniaturized and automated model allows to get predictive results, with a significant reduction in biological material, waste, and a higher screening capacity. An article about this miniaturized BBB model has been published in Pharmaceutics Journal in June 2021.
PLGA nanoparticles coated with surfactants, polysorbate 80 (PS80) or poloxamer 188 (P188) have been shown the ability to cross the BBB in animals and are thus interesting formulations for brain drug delivery. However, no data has been obtained about the interactions of these nanoformulations with human BBB endothelial cells. Thus, the original human BBB model and the miniaturized model were used to assess the interaction of these nanoformulations with the human cerebral endothelium. These PLGA nanoparticles coated with PS80 and P188, labelled with a fluorescent dye were produced by using the MicroJet reactor® technology. Results showed that both formulations presented no toxicity for the brain endothelium and that they were able to be internalized within the cells. The two formulations presented different uptake profiles depending on their coating: P188 NP showed higher internalization capacity than PS80 NP. Both NPs uptakes were ATP-dependent, following more than one endocytosis pathway, mediated by clathrin and caveolae routes; both NPs were colocalized in the early endosomes, ending with some NPs release by the BLECs in the brain compartment, being thus interesting formulations for brain drug delivery.
Congratulations for your PhD, Dr Elisa !!! It was a great pleasure working with you.
Feel free to contact us if you want more information about our cerebral in vitro models!