Cytokines, nitric oxide, and cGMP modulate the permeability of an in vitro model of the human blood-brain barrier.
The endothelial cells (EC) of the microvasculature in the brain form the anatomical basis of the blood-brain barrier (BBB). In the present study, the effects of agents that modify the permeability of a well-established in vitro model of the human BBB were studied. The monolayers formed by confluent human brain microvessel endothelial cell (HBMEC) cultures are impermeable to the macromolecule tracer horseradish peroxidase (HRP) and have high electrical resistance. Exposure of HBMEC to various cytokines including TNF-alpha, IL-1beta, interferon gamma (IFN-gamma), or lipopolysaccharide (LPS) decreased transendothelial electrical resistance (TEER) mainly by increasing the permeability of the tight junctions. Primary cultures of HBMEC express endothelial nitric oxide synthase (eNOS) and produce low levels of NO. Treatment with the NO donors sodium nitroprusside (SNP) and DETA NONOate or the cGMP agonist 8-Br-cGMP significantly increased monolayer resistance. Conversely, inhibition of soluble guanylyl cyclase with ODQ rapidly decreased the resistance, and pretreatment of HBMEC with Rp-8-CPT-cGMPS, an inhibitor of cGMP-dependent protein kinase, partially prevented the 8-Br-cGMP-induced increase in resistance. Furthermore, NO donors and 8-Br-cGMP could also reverse the increased permeability of the monolayers induced by IL-1beta, IFN-gamma, and LPS. These results indicate that NO can decrease the permeability of the human BBB through a mechanism at least partly dependent on cGMP production and cGMP-dependent protein kinase activation.
Wong
Donald
D
Department of Pathology and Laboratory Medicine, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3.
Dorovini-Zis
Katerina
K
Vincent
Steven R
SR
D001812:Blood-Brain Barrier / Q000502:physiology*; D002199:Capillary Permeability / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D016207:Cytokines / Q000378:metabolism*; D017097:Electric Impedance; D042783:Endothelial Cells / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology; D009599:Nitroprusside / Q000494:pharmacology; D009603:Nitroso Compounds / Q000494:pharmacology; D010069:Oxadiazoles / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D016207:Cytokines; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D010069:Oxadiazoles; D011810:Quinoxalines; C094210:2,2'-(hydroxynitrosohydrazono)bis-ethanamine; D009599:Nitroprusside; C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D006152:Cyclic GMP