Influence of the cellular redox state on NF-kappa B-regulated gene expression

The redox state has been shown to regulate a variety of biochemical functio ns including cellular proliferation. Previous studies from our laboratory a nd others have shown that the binding of many transcription factors to thei r cognate DNA sequences is sensitive to the redox environment. Therefore, i t is likely that redox status serves as an additional regulatory control fo r the activity of transcription factors and that this may mediate the redox regulation of proliferation. To assess this possibility, the influence of altering the redox stare on NF-kappa B-regulated gene expression was studie d. A more-reducing environment favored higher levels of expression of gro, an endogenous gene associated with proliferation, when the redox levels wer e changed either naturally by altering culture density or chemically by tre atment with modulators of glutathione synthesis. Furthermore, nuclear runof f studies showed that a more-reducing redox increased transcription of gro. In order to ascertain the singular effect of the redox state on the activi ty of NF-kappa B, expression of a secreted alkaline phosphatase (SEAP) repo rter gene solely under the control of an NF-kappa B response element was me asured under varying redox conditions. Changes in the redox stale modulated the expression of this reporter system. Taken together, these results sugg est the involvement of a redox mechanism regulating signaling events operat ing through the control of gene expression by transcription factors. (C) 20 00 Wiley-Liss, Inc.