ACTIVATION OF THE NF-KAPPA-B TRANSCRIPTION FACTOR IN A T-LYMPHOCYTIC CELL LIME BY HYPOCHLOROUS ACID

Reactive oxygen species (ROS) such as hydrogen peroxide serve as secon d messengers in the induction of the transcription factor NF-kappa B, and hence in the activation and replication of human immunodeficiency virus type 1 (HIV-1) in human cells. During inflammatory reactions, ma ny oxidative species are produced, one of which is hypochlorous acid ( HOCl), which is responsible for the microbicidal effects of activated human polymorphonuclear leukocytes. Treatment of a T-lymphocytic cell line with micromolar concentrations of HOCl promoted the appearance of transcription factor NF-kappa B (the heterodimer p50/p65) in the nucl eus of the cells, even in the absence of de novo protein synthesis. We stern blot analysis of the NF-kappa B inhibitory subunits (I kappa-B) demonstrated that both I kappa B-alpha proteolysis and p105 processing were induced by the treatment. NF-kappa B activation was very effecti ve when cells were subjected to hyperthermia before being treated with HOCl. Various antioxidants, such as pyrrolidine dithiocarbamate, p-br omophenacyl-bromide and nordihydroguaiaretic acid could strongly reduc e NF-kappa B translocation, demonstrating the importance of oxidative species in the transduction mechanism. Moreover, ACH-2 cells treated w ith HOCl or H2O2 released tumour necrosis factor-alpha (TNF-alpha) in the supernatants. The importance of TNF-alpha release in NF-kappa B in duction by HOCl or H2O2 was demonstrated by the fact that: (1) the nuc lear appearance of NF-kappa B was promoted in untreated cells; and (2) synergism between TNF-alpha and HOCl was detected. Collectively, thes e results suggest that HOCl should be considered as an oxidative speci es capable of inducing NF-kappa B in a T-lymphocytic cell line through a transduction mechanism involving ROS, and having a long-distance ef fect through subsequent TNF-alpha release.