Defined Differentiation of Human Pluripotent Stem Cells to Brain Microvascular Endothelial-Like Cells for Modeling the Blood-Brain Barrier.

The blood-brain barrier (BBB) comprises brain microvascular endothelial cells (BMECs) that form a high-resistance cellular interface that separates the blood compartment from the brain parenchyma. An intact BBB is pivotal to maintaining brain homeostasis but also impedes the entry of neurotherapeutics. There are limited options for human-specific BBB permeability testing, however. Human pluripotent stem cell models offer a powerful tool for dissecting components of this barrier in vitro, including understanding mechanisms of BBB function, and developing strategies to improve the permeability of molecular and cellular therapeutics targeting the brain. Here, we provide a detailed, step-by-step protocol for differentiation of human pluripotent stem cells (hPSCs) to cells exhibiting key characteristics of BMECs, including paracellular and transcellular transport resistance and transporter function that enable modeling the human BBB.