Published in:
Open Access
01-04-2012
Vasodilator Phosphostimulated Protein (VASP) Protects Endothelial Barrier Function During Hypoxia
Authors:
Marthe A. Schmit, Valbona Mirakaj, Manfred Stangassinger, Klemens König, David Köhler, Peter Rosenberger
Published in:
Inflammation
|
Issue 2/2012
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Abstract
The endothelial barrier controls the passage of solutes from the vascular space. This is achieved through active reorganization of the actin cytoskeleton. A central cytoskeletal protein involved into this is vasodilator-stimulated phosphoprotein (VASP). However, the functional role of endothelial VASP during hypoxia has not been thoroughly elucidated. We determined endothelial VASP expression through real-time PCR (Rt-PCR), immunhistochemistry, and Western blot analysis during hypoxia. VASP promoter studies were performed using a PGL3 firefly luciferase containing plasmid. Following approval by the local authorities, VASP
−/−
mice and littermate controls were subjected to normobaric hypoxia (8% O2, 92% N2) after intravenous injection of Evans blue dye. In in vitro studies, we found significant VASP repression in human microvascular and human umbilical vein endothelial cells through Rt-PCR, immunhistochemistry, and Western blot analysis. The VASP promoter construct demonstrated significant repression in response to hypoxia, which was abolished when the binding of hypoxia-inducible factor 1 alpha was excluded. Exposure of wild-type (WT) and VASP
−/−
animals to normobaric hypoxia for 4 h resulted in an increase in Evans blue tissue extravasation that was significantly increased in VASP
−/−
animals compared to WT controls. In summary, we demonstrate here that endothelial VASP holds significant importance for endothelial barrier properties during hypoxia.