Selective inhibition of inhibitory kappa B kinase-beta abrogates induction of nitric oxide synthase in lipopolysaccharide-stimulated rat aortic smooth muscle cells.
In this study, we utilised a number of adenoviral constructs in order to examine the role of intermediates of the NF-kappaB pathway in the regulation of inducible nitric oxide synthase (iNOS) induction in rat aortic smooth muscle cells (RASMCs). Lipopolysaccharide (LPS) stimulated a significant increase in iNOS induction and NF-kappaB DNA binding. These parameters were substantially reduced by overexpression of a wild-type Ikappa-Balpha adenoviral construct (Ad.Ikappa-Balpha), confirming a role for NF-kappaB in iNOS induction. Infection with a dominant-negative IKKalpha adenoviral construct (Ad.IKKalpha+/-) did not significantly affect iNOS induction, NF-kappaB DNA binding or Ikappa-Balpha loss. Infection of RASMCs with adenovirus encoding a dominant-negative IKKbeta (Ad.IKKbeta+/-) essentially abolished iNOS induction and activation of the NF-kappaB pathway. Pretreatment of RASMCs with a novel specific inhibitor of IKKbeta, SC-514, significantly reduced iNOS induction, NF-kappaB DNA binding and I-kappaBalpha loss in a concentration-dependent manner. In both RASMCs and human umbilical vein endothelial cells (HUVECs), infection with Ad.IKKbeta+/- also inhibited COX-2 expression in response to LPS. However, Ad.IKKalpha+/- was again without effect. These data suggest that IKKbeta plays a predominant, selective role in the regulation of NF-kappaB-dependent induction of iNOS in RASMCs.
Department of Physiology & Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, 27 Taylor Street, Glasgow G4 0NR, Scotland.
Almudena Bermejo
AB
Gomez
Christopher
C
MacKenzie
Andrew
A
Paul
Robin
R
Plevin
D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects*; D015153:Blotting, Western; D004247:DNA / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000187:drug effects; D005822:Genetic Vectors; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000201:enzymology*; D016328:NF-kappa B / Q000096:biosynthesis / Q000235:genetics; D009569:Nitric Oxide / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley
D008070:Lipopolysaccharides; D016328:NF-kappa B; D009569:Nitric Oxide; D004247:DNA