Human Choroid Plexus Endothelial Cells (HCPEC)

Human Choroid Plexus Endothelial Cells (HCPEC) are primary microvascular endothelial cells isolated from the choroid plexus stroma. In stark contrast to the tight-junction-sealed endothelium of the blood-brain barrier, HCPEC constitutively form a fenestrated, highly permeable capillary network that uniquely governs the blood-cerebrospinal fluid barrier (BCSFB). As non-immortalized diploid cells, they faithfully preserve native expression of the fenestral diaphragm protein PLVAP (PV-1), caveolin-1, and von Willebrand factor, free from the phenotypic drift of transformed lines.

A paramount advantage of HCPEC is their in-vivo-like leakiness: they exhibit low transendothelial electrical resistance and high paracellular permeability, enabling physiological passage of solutes and serving as the principal gate for leukocyte trafficking into the cerebrospinal fluid under homeostasis and disease. Upon pro-inflammatory challenge with TNF-α or IL-1β, HCPEC robustly upregulate ICAM-1 and VCAM-1, making them a superior system for dissecting the molecular mechanisms of immune cell diapedesis across fenestrated endothelium-a process critical to neuroinflammation, immune surveillance, and multiple sclerosis. Moreover, they provide a relevant substrate for studying metastatic tumor cell arrest and extravasation, as the choroid plexus is a recognized portal for cerebral metastases.

HCPEC form confluent monolayers on Transwell inserts, enabling quantitative permeability assays and co-culture with choroid plexus epithelial cells to reconstruct the complete BCSFB in vitro. Collectively, HCPEC offer an indispensable, human-specific platform for investigating endothelial fenestration biology, CNS immune entry, brain metastasis, and the delivery of therapeutics across the BCSFB.