title: Role of LOX-1 in monocyte adhesion-triggered redox, Akt/eNOS and Ca2+ signaling pathways in endothelial cells.
abstract: This study was conducted to examine the role of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in monocyte adhesion-induced redox-sensitive, Akt/eNOS and Ca2+ signaling pathways in endothelial cells (ECs). LOX-1 was blocked by an antibody-neutralizing LOX-1 TS92 or small interfering RNA. In cultured human aortic ECs, monocyte adhesion activated Rac1 and p47(phox), and increased NADPH oxidase activity and reactive oxygen species (ROS) generation within 30 min and NF-kappaB phosphorylation within 1 h, resulting in redox-sensitive gene expression. Akt and eNOS phosphorylation was induced 15 min after adding monocytes and returned to control level after 30 min, whereas NO production was not altered by monocyte adhesion. Blockade of LOX-1 blunted the monocyte adhesion-triggered redox-sensitive signaling pathway and Akt/eNOS phosphorylation in ECs. Both endothelial intracellular Ca2+ mobilization and Ca2+ influx caused by monocyte attachment were markedly attenuated by pretreatment of ECs with TS92. This suggests that LOX-1 is involved in redox-sensitive, Akt/eNOS and Ca2+ signaling pathways in monocyte adhesion to ECs independent of oxidized low-density lipoprotein (ox-LDL). Furthermore, blockade of Ca2+ inhibited monocyte adhesion-triggered Rac1 and p47(phox) activation and ROS generation in ECs, whereas Ca2+ signaling was suppressed by blockade of NADPH oxidase and ROS generation. Finally, TS92 blocked the monocyte adhesion to ECs stimulated with or without tumor necrosis factor-alpha or ox-LDL. We provide evidence that LOX-1 plays a role in redox-sensitive, Akt/eNOS and Ca2+ signaling pathways in monocyte adhesion to ECs independent of the ox-LDL-LOX-1 axis.
authors.affiliation: First Department of Internal Medicine, Fukushima Medical University, Fukushima 960-1295, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sakamoto
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ishibashi
authors.forename: Koichi
authors.initials: K
authors.lastname: Sugimoto
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Sawamura
authors.forename: Takayuki
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Inoue
authors.forename: Shu-Ichi
authors.initials: S
authors.lastname: Saitoh
authors.forename: Masashi
authors.initials: M
authors.lastname: Kamioka
authors.forename: Hironori
authors.initials: H
authors.lastname: Uekita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ohkawara
authors.forename: Koji
authors.initials: K
authors.lastname: Suzuki
authors.forename: Tamio
authors.initials: T
authors.lastname: Teramoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Maruyama
authors.forename: Yasuchika
authors.initials: Y
authors.lastname: Takeishi
mesh_terms: D000906:Antibodies; D020013:Calcium Signaling; D002448:Cell Adhesion; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000201:enzymology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D009000:Monocytes / Q000201:enzymology*; D019255:NADPH Oxidases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D034622:RNA Interference; D017382:Reactive Oxygen Species / Q000378:metabolism; D051127:Scavenger Receptors, Class E / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D013997:Time Factors; D014162:Transfection; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D000906:Antibodies; D016328:NF-kappa B; C495137:OLR1 protein, human; C107953:RAC1 protein, human; D017382:Reactive Oxygen Species; D051127:Scavenger Receptors, Class E; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; D019255:NADPH Oxidases; C060505:neutrophil cytosolic factor 1; D051057:Proto-Oncogene Proteins c-akt; D020830:rac1 GTP-Binding Protein