title: F-actin cytoskeleton and sucrose permeability of immortalised rat brain microvascular endothelial cell monolayers: effects of cyclic AMP and astrocytic factors.
abstract: The immortalised RBE4 cell line, derived from rat brain capillary endothelial cells, preserves many features of the in vivo brain endothelium, and hence is of interest as a potential in vitro model of the blood-brain barrier (BBB). This study reports the effects of elevated intracellular cAMP and factors released by astrocytes on the F-actin cytoskeleton and paracellular sucrose permeability of monolayers of RBE4 cells. RBE4 cells grown in control medium showed a marked increase in the F-actin staining at the cytoplasmic margin at confluence, which was not significantly enhanced by elevation of intracellular cAMP and/or addition of astrocyte-conditioned medium (ACM). The formation of the marginal band of F-actin was accompanied by an increase in the F-actin content of the RBE4 cells up to confluence, and a decline in F-actin content thereafter. Elevation of intracellular cAMP or co-culture above astrocytes significantly decreased the paracellular sucrose permeability of confluent RBE4 cell monolayers grown on collagen filters (P < 0.01 and P < 0.001, respectively). Co-culture above astrocytes together with elevated cAMP also produced a significant decrease in the sucrose permeability of the monolayer (P < 0.01) but this was no greater than with astrocytes alone. These findings show that the RBE4 cell line may serve as a useful in vitro model for the study of brain endothelial cell physiology and agents which alter the permeability of the BBB.
authors.affiliation: Biomedical Sciences Division, King's College London, Strand, UK.
authors.forename: R J
authors.initials: RJ
authors.lastname: Rist
authors.forename: I A
authors.initials: IA
authors.lastname: Romero
authors.forename: M W
authors.initials: MW
authors.lastname: Chan
authors.forename: P O
authors.initials: PO
authors.lastname: Couraud
authors.forename: F
authors.initials: F
authors.lastname: Roux
authors.forename: N J
authors.initials: NJ
authors.lastname: Abbott
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D000242:Cyclic AMP / Q000494:pharmacology*; D003599:Cytoskeleton / Q000187:drug effects*; D004730:Endothelium, Vascular / Q000187:drug effects*; D008833:Microcirculation / Q000187:drug effects; D008856:Microscopy, Fluorescence; D051381:Rats; D013395:Sucrose / Q000493:pharmacokinetics*
chemical_list: D000199:Actins; D013395:Sucrose; D000242:Cyclic AMP