Hypoosmolarity influences the activity of transcription factor NF-kappa B in rat H4IIE hepatoma cells

The influence of anisoosmolarity on NF-kappa B binding activity was studied in H4IIE rat hepatoma cells. Hypoosmolarity induced a sustained NF-kappa B binding activity whereas the hyperosmotic NF-kappa B response mas only min or. Hypoosmotic NF-kappa B activation was accompanied by degradation of the inhibitory I kappa B-alpha. Protein kinase C, PI3-kinase, reactive oxygen intermediates and the proteasome apparently participate in mediating the hy poosmotic effect on NF-kappa B. Hypoosmolarity plus PMA induced, amplified and prolonged I kappa B-alpha degradation and NF-kappa B binding activity. Transforming growth factor beta-induced apoptosis was diminished by hypoosm olarity. However, this anti-apoptotic effect was probably not related to KF -kappa B activation. (C) 2000 Federation of European Biochemical Societies.