The role of superoxide radical in TNF-alpha induced NF-kappaB activation.
Wang-S; Leonard-SS; Castranova-V; Vallyathan-V; Shi-X
Ann Clin Lab Sci 1999 Jul; 29(3):192-199
Electron spin resonance (ESR) spin trapping with 5-(diethioxyphosphoyl)-5-methyl-1-pyrroline N-oxide (DEPMPO) was utilized to investigate the generation of oxygen free radicals from macrophages stimulated by tumor necrosis factor-alpha (TNF-alpha). TNF-alpha stimulated macrophages generated hydroxyl (*OH) and superoxide anion (O2*-) radicals. Incubation of TNF-alpha with macrophages resulted in an activation of DNA binding activity of the nuclear transcription factor NF-kappaB. Superoxide dismutase (SOD), but not catalase or sodium formate, inhibited this NF-kappaB activation, suggesting that O2*- rather than H2O2 or *OH, radicals play the most critical role in this induction. beta-Nicotinamide adenine dinucleotide phosphate (NADPH) did not affect the NF-kappaB activation, while allopurinol, an inhibitor of xanthine oxidase, repressed it, suggesting that xanthine/xanthine oxidase, and not NADPH dependent oxidase, may be a source of O2*- radicals which induce NF-kappaB activation. 02*-is generated via reduction of molecular oxygen by xanthine and xanthine oxidase, as demonstrated by the oxygen consumption assay. The results indicate that TNF-alpha induces oxygen radical generation from macrophages. 02*- seems to play a key role in TNF-alpha-induced NF-kappaB activation in macrophages. Xanthine and xanthine oxidase appears to be a source of O2*- radicals responsible for TNF-alpha-induced NF-kappaB activation.
In-vitro-studies; Cancer; Analytical-methods; Proteins; Enzymes; Genetics
to: Xianglin Shi, Ph.D., Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, 1095 Willowdale Road, Mail Stop B167, Morgantown WV 26505
Cancer Research Methods; Research Tools and Approaches
Annals of Clinical and Laboratory Science