Nox4 mediates the expression of plasminogen activator inhibitor-1 via p38 MAPK pathway in cultured human endothelial cells.
BACKGROUND
Plasminogen Activator Inhibitor-1 (PAI-1) is the most potent endogenous inhibitor of fibrinolysis which is implicated in the pathogenesis of myocardial infarction and metabolic syndrome. The formation of reactive oxygen species (ROS) plays an important role in the pathology of vascular disorders and has been shown to increase PAI-1 expression by endothelial cells. Growing evidence indicates that NADPH oxidase and in particular the constitutively active Nox4-p22(phox) complexes are major sources of ROS in endothelial cells. The aim of the present study was to characterize the role of NADPH oxidase and in particular Nox4 in the regulation of PAI-1 expression in cultured Human Umbilical Venous Endothelial Cells (HUVECs).


RESULTS
N-acetylcysteine (NAC, scavenger of ROS), diphenylene iodonium chloride (DPI, inhibitor of flavoproteins), M40403 (superoxyde dismutase mimic) and S17834 (inhibitor of NADPH oxidase) inhibited PAI-1 release and promoter activity in HUVECs. Specific knock down of Nox4 mRNA by siRNA caused a decrease in ROS production and NADPH oxidase activity. Moreover, Nox4 silencing decreased PAI-1 expression, release and activity as well as p38 MAPK pathways and NFkappaB activation. These signalling pathways are also involved in PAI-1 release.


CONCLUSIONS
The NADPH oxidase inhibitors DPI and S 17834 as well as Nox4 silencing decreased PAI-1 synthesis in human cultured endothelial cells demonstrating the involvement of the constitutively active Nox4-containing NADPH oxidase in ROS-mediated PAI-1 transcription via p38 MAPK pathways. NADPH oxidase targeting with inhibitors such as S17834 could be an interesting strategy to decrease both oxidative stress and PAI-1 synthesis.
Jaulmes
Amandine
A
Division of Angiology, Servier Research Institute, 11 rue des Moulineaux, Suresnes, France.
Sansilvestri-Morel
Patricia
P
Rolland-Valognes
Gaëlle
G
Bernhardt
Fabienne
F
Gaertner
Roger
R
Lockhart
Brian P
BP
Cordi
Alex
A
Wierzbicki
Michel
M
Rupin
Alain
A
Verbeuren
Tony J
TJ
D000111:Acetylcysteine / Q000494:pharmacology; D001578:Benzopyrans / Q000494:pharmacology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D020935:MAP Kinase Signaling System; D008345:Manganese; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism*; D009861:Onium Compounds / Q000494:pharmacology; D009942:Organometallic Compounds / Q000494:pharmacology; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
C438505:6,8-diallyl 5,7-dihydroxy 2-(2-allyl 3-hydroxy 4-methoxyphenyl)1-H benzo(b)pyran-4-one; D001578:Benzopyrans; D009861:Onium Compounds; D009942:Organometallic Compounds; D017395:Plasminogen Activator Inhibitor 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D017382:Reactive Oxygen Species; C051321:SERPINE1 protein, human; C121876:imisopasem manganese; D008345:Manganese; C007517:diphenyleneiodonium; D000074663:NADPH Oxidase 4; D019255:NADPH Oxidases; C498910:NOX4 protein, human; D048051:p38 Mitogen-Activated Protein Kinases; D000111:Acetylcysteine