Taurine Chloramine Activates Nrf2, Increases HO-1 Expression and Protects Cells from Death Caused by Hydrogen Peroxide

Hypochlorous acid (HOCl) is toxic and causes cell death. However, this effect is inhibited by reaction with taurine, which generates taurine chloramine (TauCl), thereby protecting the cells from HOCl-generated toxicity. TauCl has been shown to inhibit the production of inflammatory mediators like O2•−, H2O2 and NO. In this study, RAW 264.7 macrophages treated with TauCl were protected from death caused by H2O2. TauCl increased the expression of peroxiredoxin-1, thioredoxin-1 and heme oxygenase (HO)-1, the anti-oxidant enzymes normally induced by activation of NF-E2-related factor-2 (Nrf2). TauCl increased nuclear translocation of Nrf2 and binding to the anti-oxidant response element. These data suggest that TauCl produced abundantly in the activated neutrophils and released to surrounding cells in the inflamed tissues may induce the expression of cytoprotective anti-oxidant enzymes. Elevation of HO activity via induction of HO-1 expression within neighboring cells may provide protection from cytotoxicity caused by inflammatory oxidants like H2O2.