Regulation of NF-kappaB activation and nuclear translocation by exogenous nitric oxide (NO) donors in TNF-alpha activated vascular endothelial cells.
Nitric oxide (NO) is a unique mediator which may promote or suppress inflammation. In this study, we examine the effect of exogenous NO on nuclear translocation of nuclear factor-kappa B (NF-kappaB) in quiescent human umbilical vein endothelial cells (HUVECs) subsequently activated by tumor necrosis factor-alpha (TNF-alpha), and in HUVECs previously activated by TNF-alpha, a model of vascular inflammation. Quiescent and activated HUVECs are exposed to exogenous NO donors of varying half-lives and the degree of NF-kappaB translocation into the nucleus determined by unique application of immunofluorescence image analysis in whole cells and correlative biochemical analysis of activated NF-kappaB proteins in the nucleus. NO donors with shorter half-lives are more effective in blocking the activation and translocation of NF-kappaB, when added to quiescent HUVECs prior to cellular activation by TNF-alpha. However, in previously activated HUVECs where NF-kappaB had relocated into the cytoplasm, addition of short half-life NO donors, but not TNF-alpha, induced re-translocation of NF-kappaB back into the nucleus sustaining the inflamed cell phenotype. These data suggest that NO as an inhibitor or activator of NF-kappaB may depend on the state of activation of vascular endothelial cells in which it contacts. Additionally, in activated cells, NO may modulate expression of NF-kappaB-dependent gene products, when cytokines are ineffective.
Rogers
Jennifer A
JA
Department of Cellular Biology and Anatomy, Louisiana State University-Health Science Center at Shreveport, Shreveport, LA 71130, USA.
Fuseler
John W
JW
D021581:Active Transport, Cell Nucleus / Q000502:physiology*; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010084:Oxidation-Reduction; D051996:Transcription Factor RelA / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D020030:Nitric Oxide Donors; D051996:Transcription Factor RelA; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide