Exposure of tumor necrosis factor-alpha to luminal membrane of bovine brain capillary endothelial cells cocultured with astrocytes induces a delayed increase of permeability and cytoplasmic stress fiber formation of actin.
Tumor necrosis factor-alpha (TNF-alpha), a proinflammatory cytokine, has long been known to be involved in the pathogenesis of central nervous system infections and of certain neurodegenerative diseases. However, the possible role of the blood-brain barrier (BBB), the active interface between the blood circulation and brain tissue, remained unknown during these pathological conditions. In our in vitro reconstructed BBB model, 1-hr exposure of recombinant human TNF-alpha (in concentrations of 50, 250, and 500 U/ml, respectively) to the luminal membrane of bovine brain capillary endothelial cells (BBCEC) did not change significantly the transendothelial flux of either sucrose (m.w. 342 Da), or inulin (m.w. 5 kDa) up to 4 hr (early phase), except for a slight decrease (P < 0.05) in sucrose permeation at 2-4 hr with the highest dose of TNF-alpha. On the other hand, at 16 hr after the 1-hr challenge with TNF-alpha (delayed phase) at all 3 concentrations, significant increase was induced in the permeability of BBCEC monolayers for both markers. These changes of permeability were accompanied by a selective reorganization of F-actin filaments into stress fibers, while the intracellular distribution of vimentin remained similar to the control. These results suggest that BBCEC can respond directly to TNF-alpha by a delayed increase of permeability and reorganization of actin filaments.
D000199:Actins / Q000187:drug effects*; D000818:Animals; D001253:Astrocytes / Q000187:drug effects; D001812:Blood-Brain Barrier; D001921:Brain / Q000187:drug effects*; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000187:drug effects*; D008566:Membranes / Q000187:drug effects; D018613:Microscopy, Confocal; D010539:Permeability / Q000187:drug effects*; D013395:Sucrose / Q000378:metabolism; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D000199:Actins; D014409:Tumor Necrosis Factor-alpha; D013395:Sucrose