Lipopolysaccharide-activated microglia induce dysfunction of the blood-brain barrier in rat microvascular endothelial cells co-cultured with microglia.
The blood-brain barrier (BBB) is formed by brain capillary endothelial cells, astrocytes, pericytes, microglia, and neurons. BBB disruption under pathological conditions such as neurodegenerative disease and inflammation is observed in parallel with microglial activation. To test whether activation of microglia is linked to BBB dysfunction, we evaluated the effect of lipopolysaccharide (LPS) on BBB functions in an in vitro co-culture system with rat brain microvascular endothelial cells (RBEC) and microglia. When LPS was added for 6 h to the abluminal side of RBEC/microglia co-culture at a concentration showing no effects on the RBEC monolayer, transendothelial electrical resistance was decreased and permeability to sodium-fluorescein was increased in RBEC. Immunofluorescence staining for tight junction proteins demonstrated that zonula occludens-1-, claudin-5-, and occludin-like immunoreactivities at the intercellular borders of RBEC were fragmented in the presence of LPS-activated microglia. These functional changes induced by LPS-activated microglia were blocked by the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor, diphenyleneiodonium chloride. The present findings suggest that LPS activates microglia to induce dysfunction of the BBB by producing reactive oxygen species through NADPH oxidase.
Sumi
Noriko
N
Department of Pharmaceutical Care and Health Sciences, Faculty of Pharmaceutical Sciences, Fukuoka University, 8-19-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
Nishioku
Tsuyoshi
T
Takata
Fuyuko
F
Matsumoto
Junichi
J
Watanabe
Takuya
T
Shuto
Hideki
H
Yamauchi
Atsushi
A
Dohgu
Shinya
S
Kataoka
Yasufumi
Y
D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000503:physiopathology; D002463:Cell Membrane Permeability; D018920:Coculture Techniques; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D008070:Lipopolysaccharides / Q000494:pharmacology*; D017628:Microglia / Q000166:cytology / Q000187:drug effects* / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism
D008070:Lipopolysaccharides; D017382:Reactive Oxygen Species