title: Rac1 and superoxide are required for the expression of cell adhesion molecules induced by tumor necrosis factor-alpha in endothelial cells.
abstract: Oxidative signals play an important role in the regulation of endothelial cell adhesion molecule expression. Small GTP-binding protein Rac1 is activated by various proinflammatory substances and regulates superoxide generation in endothelial cells. In the present study, we demonstrate that adenoviral-mediated expression of dominant negative N17Rac1 (Ad.N17Rac1) suppresses tumor necrosis factor-alpha (TNF-alpha)-induced vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), and E-selectin gene expression in a dose-dependent manner. Ad.N17Rac1 did not inhibit TNF-alpha-induced activation of nuclear factor-kappaB (NF-kappaB) binding activity or inhibitor of NF-kappaB-alpha degradation. In contrast, Ad.N17Rac1 inhibited TNF-alpha-induced NF-kappaB-driven HIV(kappaB)(4)-CAT and p288VCAM-Luc promoter activity, suggesting that N17Rac1 inhibits TNF-alpha-induced VCAM-1, E-selectin, and ICAM-1 through suppressing NF-kappaB-mediated transactivation. In addition, expression of superoxide dismutase by adenovirus suppressed TNF-alpha-induced VCAM-1, E-selectin, and ICAM-1 mRNA accumulation. However, adenoviral-mediated expression of catalase only partially inhibited TNF-alpha-induced E-selectin gene expression and had no effect on VCAM-1 and ICAM-1 gene expression. These data suggest that Rac1 and superoxide play crucial roles in the regulation of expression of cell adhesion molecules in endothelial cells.
authors.affiliation: Discovery Research, AtheroGenics, Inc., 8995 Westside Parkway, Alpharetta, GA 30004, USA. xchen@atherogenics.com
authors.forename: Xi-Lin
authors.initials: XL
authors.lastname: Chen
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ruozhi
authors.initials: R
authors.lastname: Zhao
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Ding
authors.forename: Pradyumna E
authors.initials: PE
authors.lastname: Tummala
authors.forename: Russell M
authors.initials: RM
authors.lastname: Medford
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D015152:Blotting, Northern; D002374:Catalase / Q000096:biosynthesis; D015815:Cell Adhesion Molecules / Q000096:biosynthesis* / Q000235:genetics; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D016207:Cytokines / Q000096:biosynthesis; D019040:E-Selectin / Q000096:biosynthesis / Q000235:genetics; D024202:Electrophoretic Mobility Shift Assay; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D010957:Plasmids / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013268:Stimulation, Chemical; D013482:Superoxide Dismutase / Q000096:biosynthesis; D013481:Superoxides / Q000378:metabolism*; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects; D019010:Vascular Cell Adhesion Molecule-1 / Q000096:biosynthesis / Q000235:genetics; D020830:rac1 GTP-Binding Protein / Q000235:genetics / Q000378:metabolism*
chemical_list: D015815:Cell Adhesion Molecules; D016207:Cytokines; D019040:E-Selectin; D016328:NF-kappa B; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D013481:Superoxides; D018799:Intercellular Adhesion Molecule-1; D006861:Hydrogen Peroxide; D002374:Catalase; D013482:Superoxide Dismutase; D020830:rac1 GTP-Binding Protein