ZO-1 redistribution and F-actin stress fiber formation in pulmonary endothelial cells after XXXX .

@entity1 @entity10034 @entity13293 @entity130
BACKGROUND: In response to isolated inflammatory stimuli, changes in endothelial cell morphology that enhance paracellular flow of solutes result from F-actin stress fiber formation, myosin phosphorylation, and actin anchoring protein (ZO-1) modifications. We hypothesized that myosin light chain kinase inhibition would diminish burn-enhanced endothelial monolayer permeability by secondarily preventing F-actin and actin anchoring protein rearrangements. METHODS: @entity1 pulmonary microvascular endothelial cells were treated for 4 hours with 20% human burn serum (isolated from @entity1 with > 45% total body surface area @entity130 or healthy volunteers). Select cultures were pretreated with myosin light chain kinase inhibitors ( @entity13293 ). Permeability was assessed by migration of bovine serum albumin across cell monolayers. Cells were stained with @entity10034 and anti-ZO-1 antisera and examined by means of confocal microscopy. RESULTS: Burn serum significantly enhanced monolayer permeability to albumin, whereas pretreatment with @entity13293 limited this effect. Control cells maintained cortical F-actin and peripheral ZO-1 distributions (1a, b), whereas burn serum induced transcellular F-actin stress fiber formation and a diffuse ZO-1 staining (2a, b). @entity13293 prevented burn-induced actin rearrangements, but not the diffuse redistribution of ZO-1. CONCLUSION: These data demonstrate that endothelial F-actin stress fiber formation and ZO-1 redistribution contribute to postburn loss of pulmonary endothelial monolayer integrity. Although myosin phosphorylation appears to be required for endothelial F-actin stress fiber formation, redistribution of actin-membrane anchoring proteins appears to be regulated independently after @entity130 .
