Nitration of respiratory epithelial cells by myeloperoxidase depends on extracellular nitrite.

摘要: To investigate peroxidase induced 3'-nitrotyrosine (3NT) formation, neutrophil derived myeloperoxidase (MPO) (0.025 microM) was directly administered to A549 epithelial cells with or without H(2)O(2) (150 microM). Little evidence of 3NT found. In contrast, there a dose dependent increase in intracellular NO (p =100 microM), which 3NT. protein carbonyl formation and increased GSSG/GSH ratios were associated MPO treatment even the absence NO(2)(-). Co-culture polymorphonuclear leukocytes (PMN) (10(6)/ml) led immunocytochemical detection induction nitric oxide synthase (NOS2). However, Transwell system direct contact between PMN necessary for immunodetection but not NOS2 consistent role high local nitrite concentrations. These findings demonstrate dissociation endogenous production formation. Although can influence cellular oxidative stress, particularly presence H(2)O(2), requires concentrations NO(2)(-) milieu.