Resealing of endothelial junctions by focal adhesion kinase

• Published in: American journal of physiology. Lung cellular and molecular physiology Vol. 292; no. 1; pp. L334 - L342
• Main Authors: Quadri, Sadiqa K, Bhattacharya, Jahar
• Format: Journal Article
• Language: English
• Published: United States American Physiological Society 01.01.2007
• Subjects: Adherens Junctions - drug effects; Adherens Junctions - enzymology; Adherens Junctions - ultrastructure; Adhesion; Animals; Cadherins - metabolism; Cell adhesion & migration; Cells, Cultured; Endothelial Cells - drug effects; Endothelial Cells - enzymology; Endothelial Cells - ultrastructure; Enzymes; Focal Adhesion Kinase 1 - deficiency; Focal Adhesion Kinase 1 - genetics; Focal Adhesion Kinase 1 - physiology; Green Fluorescent Proteins - metabolism; Hydrogen peroxide; Hydrogen Peroxide - toxicity; Lungs; Membrane Potentials - drug effects; Oxidants - toxicity; Oxidizing agents; Rats; Recombinant Fusion Proteins - metabolism; Rodents; Signal Transduction - drug effects
• ISSN: 1040-0605; 1522-1504
• DOI: 10.1152/ajplung.00228.2006

Lung Biology Laboratory, College of Physicians and Surgeons, Columbia University, St. Luke's-Roosevelt Hospital Center, New York, New York Submitted 20 June 2006 ; accepted in final form 24 September 2006 Endothelial cell (EC) junctions determine vascular barrier properties and are subject to transient opening to allow liquid flux from blood to tissue. Although EC junctions open in the presence of permeability-enhancing factors, including oxidants, the mechanisms by which they reseal remain inadequately understood. To model opening and resealing of EC junctions in the presence of an oxidant, we quantified changes in H 2 O 2 -induced transendothelial resistance (TER) in monolayers of rat lung microvascular EC. During a 30-min exposure, H 2 O 2 (100 µM) decreased TER for an initial 10 min, indicating junctional opening. Subsequently, despite continuous presence of H 2 O 2 , TER recovered to baseline, indicating the activation of junctional resealing mechanisms. These bimodal TER transients matched the time course of loss and then gain of E-cadherin at EC junctions. The timing of the TER decrease matched the onset of focal adhesion formation, while F-actin increase at the cell periphery occurred with a time course that complemented the recovery of peripheral E-cadherin. In monolayers expressing a focal adhesion kinase (FAK) mutant (del-FAK) that inhibits FAK activity, the initial H 2 O 2 -induced junctional opening was present, although the subsequent junctional recovery was blocked. Expression of transfected E-cadherin was evident at the cell periphery of wild-type but not del-FAK-expressing EC. E-cadherin overexpression in del-FAK-expressing EC failed to effect major rescue of the junctional resealing response. These findings indicate that in oxidant-induced EC junction opening, FAK plays a critical role in remodeling the adherens junction to reseal the barrier. endothelial cells; E-cadherin; barrier regulation; transendothelial resistance Address for reprint requests and other correspondence: S. Quadri, St. Luke's-Roosevelt Hospital Center, AJA 509, 432 West 58th St., Rm. 509, New York, NY 10019 (e-mail: skq1{at}columbia.edu )