Figure 5.
Effect of cytoskeletal alterations on Sph-1-P–induced endothelial cell barrier protection. (a) Bovine endothelium, grown on gold microelectrodes, was pretreated with either vehicle or cytochalasin B (CytB; 25 μg/ml, 60 minutes), followed by stimulation with Sph-1-P (1 μM). Actin depolymerization and disruption of microfilament structure decreases TER and completely prevented the effect of Sph-1-P on TER. (b) Human endothelial cells were pretreated with either vehicle or latrunculin A (Lat; 0.1 μM, 40 minutes), followed by stimulation with Sph- 1-P (1 μM). Inhibition of actin polymerization decreases basal level TER and prevented Sph-1-P–mediated TER. (c) Bovine endothelial cells were incubated with either vehicle or the microtubule-disrupting agent, nocodazole (ND; 2.5 μM, 30 minutes), followed by stimulation with Sph-1-P (1 μM). Disruption of microtubule decreases TER, but failed to alter Sph-1-P–induced increases in TER.