Twist1 regulates lung vascular barrier function through the Ang-Tie2 pathway.

<p>Vascular permeability in the lung can be controlled by Twist1-Tie2 signaling depending on the Ang1/Ang2 ratio. In physiological conditions where the ratio of Ang1 and Ang2 is in favor of Ang1, knockdown of Twist1, which decreases the expression of Tie2, increases vascular permeability in the lung. However, during a pathological condition such as endotoxin-induced lung injury, in which Ang2 is upregulated [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073407#B12" target="_blank">12</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073407#B13" target="_blank">13</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0073407#B38" target="_blank">38</a>], knockdown of Twist1 fails to increase vascular permeability, rather reverses the increase of vascular leakage in the lungs.