title: NO modulates monocyte chemotactic protein-1 expression in endothelial cells under cyclic strain.
abstract: Endothelial cells (ECs) under hemodynamic forces increase intracellular reactive oxygen species (ROS) that modulate gene expression. We previously showed that NO attenuated the shear flow-induced gene level. The present study explored the role of endothelial NO in cyclic strain-treated ECs. Treatment of ECs with S-nitroso-N-acetylpenicillamine (SNAP), an NO donor, reduced cyclic strain-induced monocyte chemotactic protein (MCP)-1 expression. Conversely, exposure of ECs to an NO synthase inhibitor augmented MCP-1 mRNA levels. NO attenuated the binding of activator protein-1 to the 12-O-tetradecanoylphobol-13-acetate-responsive element (TRE) in the MCP-1 promoter region. ECs overexpressed with endothelial NO synthase (eNOS) inhibited cyclic strain-induced MCP-1 expression and MCP-1 promoter (-540 bp) activity. Consistently, ECs treated with SNAP or infected with adenovirus carrying eNOS reduced strain-induced superoxide levels. These strain-induced superoxide and MCP-1 expressions were greatly blunted by treating ECs with an NADPH oxidase inhibitor, diphenyleneiodonium chloride or apocynine, but not with a xanthine oxidase inhibitor. ECs infected with adenovirus carrying the dominant-negative mutant of Rac (RacN17), a component of NADPH oxidase, reduced the strain-induced superoxide and MCP-1 expression. In contrast, ECs transfected with a constitutively active Rac (RacV12) increased MCP-1 and 4x TRE promoter activities. However, ECs cotransfected with eNOS and RacV12 reduced those promoter activities. Consistently, the increases of superoxide levels and MCP-1 expression by overexpression of RacV12 were abolished after infecting ECs with eNOS. Our results show that NO from eNOS-inhibiting redox-sensitive MCP-1 expression is mediated via Rac-dependent NADPH oxidase by reducing ROS. This study provides a molecular basis to support the notion that endothelial NO acts as an antioxidant by negatively regulating redox-sensitive gene expression in ECs constantly under hemodynamic influence.
authors.affiliation: Cardiovascular Division, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, ROC.
authors.forename: B S
authors.initials: BS
authors.lastname: Wung
authors.forename: J J
authors.initials: JJ
authors.lastname: Cheng
authors.forename: S K
authors.initials: SK
authors.lastname: Shyue
authors.forename: D L
authors.initials: DL
authors.lastname: Wang
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000235:genetics* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D015870:Gene Expression; D018014:Gene Transfer Techniques; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D019255:NADPH Oxidases / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D019001:Nitric Oxide Synthase / Q000235:genetics; D010084:Oxidation-Reduction; D017382:Reactive Oxygen Species / Q000378:metabolism; D013314:Stress, Mechanical; D013481:Superoxides / Q000378:metabolism; D014158:Transcription, Genetic; D014471:Umbilical Veins / Q000166:cytology; D020744:rac GTP-Binding Proteins / Q000378:metabolism
chemical_list: D018932:Chemokine CCL2; D017382:Reactive Oxygen Species; D013481:Superoxides; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D019255:NADPH Oxidases; D020744:rac GTP-Binding Proteins