NADPH oxidase mediates vascular endothelial cadherin phosphorylation and endothelial dysfunction.
Vascular endothelial activation is an early step during leukocyte/endothelial adhesion and transendothelial leukocyte migration in inflammatory states. Leukocyte transmigration occurs through intercellular gaps between endothelial cells. Vascular endothelial cadherin (VE-cadherin) is a predominant component of endothelial adherens junctions that regulates intercellular gap formation. We found that tumor necrosis factor (TNF) caused tyrosine phosphorylation of VE-cadherin, separation of lateral cell-cell junctions, and intercellular gap formation in human umbilical vein endothelial cell (HUVEC) monolayers. These events appear to be regulated by intracellular oxidant production through endothelial NAD(P)H (nicotinamide adenine dinucleotide phosphate) oxidase because antioxidants and expression of a transdominant inhibitor of the NADPH oxidase, p67(V204A), effectively blocked the effects of TNF on all 3 parameters of junctional integrity. Antioxidants and p67(V204A) also decreased TNF-induced JNK activation. Dominant-negative JNK abrogated VE-cadherin phosphorylation and junctional separation, suggesting a downstream role for JNK. Finally, adenoviral delivery of the kinase dead PAK1(K298A) decreased TNF-induced JNK activation, VE-cadherin phosphorylation, and lateral junctional separation, consistent with the proposed involvement of PAK1 upstream of the NADPH oxidase. Thus, PAK-1 acts in concert with oxidase during TNF-induced oxidant production and loss of endothelial cell junctional integrity.
Department of Surgery, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX 75390-9156, USA. fiemu.nwariaku@utsouthwestern.edu.
Fiemu E
FE
Nwariaku
Zijuan
Z
Liu
Xudong
X
Zhu
Dorit
D
Nahari
Christine
C
Ingle
Ru Feng
RF
Wu
Ying
Y
Gu
George
G
Sarosi
Lance S
LS
Terada
D015703:Antigens, CD; D000975:Antioxidants / Q000494:pharmacology; D015820:Cadherins / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000166:cytology / Q000201:enzymology*; D006801:Humans; D007365:Intercellular Junctions / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D019255:NADPH Oxidases / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D054462:p21-Activated Kinases; D000099152:Cadherin 5
D015703:Antigens, CD; D000975:Antioxidants; D015820:Cadherins; D048031:JNK Mitogen-Activated Protein Kinases; D019255:NADPH Oxidases; D016877:Oxidants; D017346:Protein Serine-Threonine Kinases; D014409:Tumor Necrosis Factor-alpha; D054462:p21-Activated Kinases; D000099152:Cadherin 5; C515903:PAK1 protein, human