Protein tyrosine phosphatase activity regulates endothelial cell-cell interactions, the paracellular pathway, and capillary tube stability

Abstract

. Protein tyrosine phosphatase activity regulates endothelial cell-cell interactions, the paracellular pathway, and capillary tube stability. Am J Physiol Lung Cell Mol Physiol 285: L63-L75, 2003. First published March 7, 2003 10.1152/ajplung.00423.2002-Protein tyrosine phosphorylation is tightly regulated through the actions of both protein tyrosine kinases and protein tyrosine phosphatases. In this study, we demonstrate that protein tyrosine phosphatase inhibition promotes tyrosine phosphorylation of endothelial cell-cell adherens junction proteins, opens an endothelial paracellular pathway, and increases both transendothelial albumin flux and neutrophil migration. Tyrosine phosphatase inhibition with sodium orthovanadate or phenylarsine oxide induced dose-and time-dependent increases in [14 C]bovine serum albumin flux across postconfluent bovine pulmonary artery endothelial cell monolayers. These increases in albumin flux were coincident with actin reorganization and intercellular gap formation in both postconfluent monolayers and preformed endothelial cell capillary tubes. Vanadate (25 M) increased tyrosine phosphorylation of endothelial cell proteins 12-fold within 1 h. Tyrosine phosphorylated proteins were immunolocalized to the intercellular boundaries, and several were identified as the endothelial cell-cell adherens junction proteins, vascular-endothelial cadherin, and ␤-, ␥-, and p120-catenin as well as platelet endothelial cell adhesion molecule-1. Of note, these tyrosine phosphorylation events were not associated with disassem-

ICAM-1-Mediated, Src- and Pyk2-Dependent Vascular Endothelial Cadherin Tyrosine Phosphorylation Is Required for Leukocyte Transendothelial Migration

“…Pervanadate treatment of EC has previously been shown to increase tyrosine phosphorylation of AJ proteins as well as increasing neutrophil TEM (16,18). We confirmed these findings in our system as well (data not shown).…”

“…Numerous lines of evidence have demonstrated that tyrosine phosphorylation of endothelial adherens junction proteins is associated with the dissociation of junctions (15)(16)(17)(18). Although much is known about the role of tyrosine phosphorylation in regulating the general maintenance of adherens junctions in endothelia, the role of tyrosine phosphorylation of EC adherens junction proteins as it relates specifically to leukocyte TEM has not been fully explored.…”

TNF-α increases tyrosine phosphorylation of vascular endothelial cadherin and opens the paracellular pathway through fyn activation in human lung endothelia

“…Prior studies have suggested that protein tyrosine phosphorylation plays a key role in the regulation of endothelial barrier function (3,11,15,20,42,54,55). In the present studies, we demonstrate that TNF-␣ increases the tyrosine phosphorylation states of EC proteins and identify several substrates for TNF-␣-induced tyrosine phosphorylation as ZA proteins.…”

“…HMVEC-L were cultured at 4 ϫ 10 5 EC/3 ml in each well of a Matrigel (BD Discovery Labware; Bedford, MA)-coated six-well plate and incubated for 16 h to allow for EC capillary tube formation as described previously (54). The preformed tubes were incubated for 6 h with TNF-␣ (100 U/ml) or medium alone, after which they were visualized through an inverted Zeiss microscope and photographed with a digital camera.…”

Pleural Mesothelial Cells Express Both BLT2 and PPARα and Mount an Integrated Response to Pleural Leukotriene B4

“…A first step in the activation of STAT-1 is the phosphorylation of tyrosine residues, and this event is tightly regulated by protein tyrosine kinases and protein tyrosine phosphatases (13,14). The effect of herbimycin (a tyrosine kinases inhibitor) and of sodium ortho vanadate (a phosphotyrosine phosphatases inhibitor) on the expression of ICAM-1 was determined.…”