(Korean Dandelion) Extract Protects Against Lipopolysaccharide-Induced Blood-Brain Barrier Destruction via Regulation of Tight Junctions and Inflammatory Responses in bEnd.3 Cells.

Dysfunction of the blood-brain barrier (BBB) is closely related to neuroinflammation-mediated neurodegenerative disorders. Lipopolysaccharide (LPS), an endotoxin, can cause inflammation by impairing the brain endothelial barrier function and increasing the BBB permeability. Although NAKAI extract (TC), a traditional medicine widely used in Korea, has antioxidant and anti-inflammatory properties, the protective effects on neuroinflammation and BBB dysfunction are not fully understood. In the present study, bEnd.3 cerebral vascular endothelial cells were treated with TC followed by LPS exposure, and the effects on transendothelial electrical resistance (TEER) values, pro-inflammatory cytokine production, and expression of proteins related to inflammatory responses and tight junction integrity were assessed. The TC-treated group exhibited elevated TEER values in bEnd.3 monolayer compared to LPS-only treated group. In addition, TC treatment increased the expression of proteins involved in the tight junctions, such as ZO-1, claudin-5, and occludin. Furthermore, the TC-treated group suppressed the proteins expression-related to nuclear factor-κB (NF-κB) pathway. Taken together, TC attenuates LPS-induced neuroinflammatory responses by regulating NF-κB activation, which may contribute to protecting against BBB disruption. These findings suggest that TC may have the potential to be used as a material for functional foods to prevent neuroinflammation-related brain diseases.