Taurine chloramine produced by neutrophil protects macrophages from H2O2-derived cytotoxicity by induction of antioxidant enzymes like HO-1, Prx-1, Trx-1 and catalase

초록

Taurine chloramine produced by neutrophil protects macrophages from H2O2-derived cytotoxicity by induction of antioxidant enzymes like HO-1, Prx-1, Trx-1 and catalase S. Piao1, 2, 3; C. Suh4; Y. Cha1, 2; C. Kim1, 2, 4 1. Pharmacology and Toxicology, Inha University Medicine School , Incheon, Korea, Republic of. 2. BK21 Program Inha University School of Medicine, Incheon , Korea, Republic of. 3. Laboratory for leukocyte Singaling Research, Incheon , Korea, Republic of. 4. Physiology, Inha University Medicine School, Incheon, Korea, Republic of. Taurine chloramine (TauCl) is produced in the activated neutrophils by reaction between the stored taurine and the newly overproduced hypochlorous acid, the product of neutrophilic myeloperoxidase halide system intended to kill the phagocytosed bacteria. TauCl has been shown to exert both anti-inflammatory and cytoprotective effects in inflammatory tissues by inhibiting the production of inflammatory mediators such as NO, O2-, ONOO-, and H2O2 by the activated phagocytes. Recently, we reported that TauCl induced heme oxygenase 1 (HO-1) expression and elevated HO activity in RAW 264.7 macrophages. HO degrades the potentially damaging free heme to biliverdin, iron and carbon monoxide to inhibit Fenton reaction and also to provide the anti-inflammatory and antioxidant actions. In this study, we investigated whether TauCl could protect cells against the hydrogen peroxide (H2O2)-derived cytotoxic effect in RAW 264.7 macrophages. Macrophages exposed to exogenous H2O2 are known to undergo apoptosis and death. However, macrophages pretreated with TauCl were protected from the H2O2-derived apoptosis and death and increased cell viability in a time- and concentration-dependent manner of TauCl pretreatment. TauCl lowered cellular glutathione (GSH) level initially, which increased the expression of Nrf2-regulated cytoprotective anti-oxidant enzymes like peroxiredoxin (Prx)-1, thioredoxin (Trx)-1, HO-1. TauCl also increased catala