Abstract 20527: Nrf2 Signaling Modulates Human Endothelial Cell Barrier Regulation by S1P
Endothelial cell (EC) barrier dysfunction results in increased vascular permeability observed in inflammation, tumor angiogenesis, and atherosclerosis. The platelet-derived phospholipid, sphingosine-1-phosphate (S1P), decreases EC permeability in vitro and in vivo, features of obvious therapeutic potential. Oxidative stress is a common primary or secondary cause of vascular hyperpermeability in multiple pathological conditions, including inflammation, and exposure to excessive mechanical stress. Thus it is important to understand the relationship between S1P-mediated vascular protection and oxidative stress-induced barrier disruption. We examined the interaction of S1P and human pulmonary artery EC signaling and barrier regulation by the oxidative stress signaling mediator, Nrf2. Human pulmonary ECs pre-treated with either tBHQ (Nrf2 inducer) or Brusatol (Nrf2 inhibitor), were evaluated by transendothelial electric resistance (TER) in response to S1P or thrombin. tBHQ clearly augmented S1P-mediated endothelial barrier enhancement. In parallel, brusatol reduced the S1P-mediated endothelial barrier enhancement. In addition, neither tBHQ or brusatol modified the peak effects of thrombin-induced endothelial barrier disruption. However, tBHQ accelerated the recovery of endothelial barrier disruption induced by thrombin, whereas brusatol retarded EC recovery process. Furthermore, we demonstrated that tBHQ enhanced S1P mediated cortical actin polymerization and barrier enhancement, whereas Brusotal enhanced stress fiber formation in endothelial cells and inhibited S1P-mediated cortical actin formation confirming the active role of Nrf2 signaling in S1P-mediated endothelial barrier regulation. The effect of Brusatol on endothelial barrier function was confirmed by Nrf2 siRNA. These functional analyses confirm the importance of Nrf2 signaling in EC barrier restoration, a highly relevant response in acute lung inflammation resolution and lung fluid balance and further define a novel role of Nrf2-dependent signaling in vascular barrier regulation and cytoskeleton rearrangements
Author Disclosures: T. Jiang: None. J.B. Mascarenhas: None. V. Ramamoorthi Elangovan: None. T. Wang: None. D.D. Zhang: None. J.G. Garcia: None.
- © 2014 by American Heart Association, Inc.