Taurine chloramine inhibits superoxide anion production by regulating NADPH oxidase components.

초록

NADPH oxidase is a membrane-associated enzyme complex that generates superoxide anion (O2-). Upon stimulation, the cytosolic components of NADPH oxidase, p47phox, p40phox, p67phox and small GTPase, Rac move to plasma membrane and become associated with the membrane components of NADPH oxidase, gp91phox and p22phox. We previously showed that taurine chloramine (Tau-Cl) inhibits O2- production in mouse peritoneal polymorphonuclear cells. In this study, we investigated the mechanisms underlying the inhibition effect of Tau-Cl on O2- production using a human myeloid leukemia cell line, PLB-985 cells. Tau-Cl inhibited the phorbol myristate acetate (PMA)-elicited O2- production which was measured by cytochrome c reduction and nitroblue tetrazolium assay. Tau-Cl also inhibited PMA-stimulated translocation of p47phox and p67phox to plasma membrane, but not Rac. In addition, Tau-Cl inhibited phosphorylation of p47phox. These results suggest that the deceased PMA-elicited O2- production by Tau-Cl in PLB-985 cells may be caused by the inhibition of NADPH oxidase assembly rather than interaction with assembled NADPH oxidase complex.