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-α (TNF-α)-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-α-induced activation of nuclear factor-κB (NF-κB) binding activity or inhibitor of NF-κB-α degradation. In contrast, Ad.N17Rac1 inhibited TNF-α-induced NF-κB-driven HIV(κB)4-CAT and p288VCAM-Luc promoter activity, suggesting that N17Rac1 inhibits TNF-α-induced VCAM-1, E-selectin, and ICAM-1 through suppressing NF-κB-mediated transactivation. In addition, expression of superoxide dismutase by adenovirus suppressed TNF-α-induced VCAM-1, E-selectin, and ICAM-1 mRNA accumulation. However, adenoviral-mediated expression of catalase only partially inhibited TNF-α-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.
Footnotes
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This study was supported by the National Institutes of Health Research Grant R01-HL-60135 (to X.C.), American Heart Association Grant-in-Aid (to X.C.), and by an unrestricted research grant from AtheroGenics, Inc. (to R.M.M.).
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DOI: 10.1124/jpet.102.047894
- Abbreviations:
- VCAM-1
- vascular cell adhesion molecule-1
- ICAM-1
- intercellular cell adhesion molecule-1
- TNF-α
- tumor necrosis factor-α
- NF-κB
- nuclear factor-κB
- IκB
- inhibitor of NF-κB
- MCP-1
- monocyte chemoattractant protein-1
- ROS
- reactive oxygen species
- IL
- interleukin
- HAECs
- human aortic endothelial cells
- HMECs
- human microvascular endothelial cells
- CAT
- chloramphenicol acetyltransferase
- ELISA
- enzyme-linked immunosorbent assay
- MOI
- multiplicity of infection
- Ad
- adenoviral
- SOD
- superoxide dismutase
- PI3K
- phosphatidylinositol 3-kinase
- HIV
- human immunodeficiency virus
- Received December 10, 2002.
- Accepted January 30, 2003.
- The American Society for Pharmacology and Experimental Therapeutics
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