Taurine chloramine inhibits the production of nitric oxide in lipopolysaccharide-stimulated RAW 264.7 cells by Regulating the activation of ERK and NF-kB

초록

Taurine is an abundant free amino acid in inflammatory cells, and protects cells from the damage. The mechanism of protection is uncertain, but one possibility is that taurine reacts with cytotoxic HOCl/OCl- to produce more stable but less toxic taurine chloramine (Tau-Cl). To understand the role of Tau-Cl, the effect of Tau-Cl on nitric oxide (NO) production was evaluated in murine macrophage cell line, RAW 264.7. Tau-Cl inhibited NO production and iNOS gene expression in lipopolisaccharide (LPS)-stimulated cells. We further inverstigated the effect of Tau-Cl on p38 mitogen-activated protein kinases (MAPK) and extracellular signal-regulated kinase (ERKs). Tau-Cl inhibited LPS-stimulated phosphorylation of ERK1/2, while had no effect on p38 MAPK activation. We also investigated the effect of Tau-Cl on nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), important transcription factors of iNOS in LPS-stimulated cells using gel mobility shift assays. Tau-Cl selectively inhibited activation of NF-κB, but not AP-1. Taken together, our results suggest that Taurine and Tau-Cl inhibit endotoxic-induced NO overproduction by regulating ERK1/2 signaling pathway and NF-κB activation.