The blood-brain barrier (BBB) is the interface between the circulatory system and the brain, which is responsible for maintaining brain homeostasis by controlling the cellular and molecular transport into the brain. Due to phenotypic differences between the BBB of mice and humans, substantial attention has been placed on the development of in vitro platforms that are able to recapitulate the key features of the human BBB. BBB models derived from human induced pluripotent stem cells (hiPSCs) exhibit superior barrier properties compared to other existing models; however, most studies with these cells have been carried out in conventional 2-D platforms that lack certain features of the human BBB. The purpose of this dissertation is to improve the functionality of hiPSC-derived BBB models by adding physiologically relevant complexity to their culture systems. In chapter 1, the BBB structure and function is discussed in more detail and the advantages and drawbacks of existing in vivo and in vitro models of the BBB are reviewed. In chapter 2, a BBB-on-a-chip device that supports perfusion and co-culture with an astrocyte-laden 3-D hydrogel is described. Since all the cells used to seed the devices were differentiated from hiPSCs, the fabricated BBB-on-a-chip platform can be used for genetic and rare disease modeling and personalized medicine applications. In chapter 3, the effect of laminins present in the endothelial basement membrane, specifically laminin 411 and laminin 511, on iBMEC functionality was investigated and compared to a commonly used collagen IV and fibronectin mixture. Based on our results, incorporation of laminin 511 in hiPSC-derived BBB models resulted in enhanced long-term barrier properties and improved shear stress response in the cells. In chapter 4, the effect of IL-1β, which was highly upregulated in brain-seeking triple negative breast cancer (TNBC) cells, on barrier tightness, gene and protein expression of iBMECs was studied. Moreover, using the BBB-on-a-chip device described in chapter 2, the extravasation potential of TNBC cells in different conditions was assessed. Our results suggest a promoting function for IL-1β in TNBC transmigration into the brain. Finally, concluding comments and recommendations for future studies are offered in chapter 5.
University of Minnesota Ph.D. dissertation. December 2020. Major: Chemical Engineering. Advisor: Samira Azarin. 1 computer file (PDF); ix, 146 pages.
Adding Physiologically Relevant Complexity to Human Induced Pluripotent Stem Cell-Derived Blood-Brain Barrier Models.
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