Pfeiffer S, Lass A, Schmidt K, Mayer B
Institut für Pharmakologie und Toxikologie, Karl-Franzens-Universität Graz, A-8010 Graz, Austria.
FASEB J. 2001 Nov;15(13):2355-64. doi: 10.1096/fj.01-0295com.
Tyrosine nitration is considered a key reaction of peroxynitrite-triggered tissue injury in inflammatory diseases. We investigated the potential involvement of peroxynitrite in protein tyrosine nitration in isolated murine peritoneal macrophages activated either in vitro with interferon-gamma/lipopolysaccharide or in vivo by priming mice with Corynebacterium parvum (10 mgxkg-1). Both protocols led to release of NO and accumulation of nitrite accompanied by formation of protein-bound 3-nitrotyrosine. Oxidation of dihydrorhodamine 123, a measure of peroxynitrite release, remained close to basal levels upon in vitro activation of the macrophages but was increased approximately twofold in vivo. Tyrosine nitration in macrophages activated in vitro was inhibited by catalase and the time course of nitration correlated with nitrite accumulation, whereas superoxide (O2*-) and H2O2 release occurred at much earlier times. To address the contribution of O2*- and peroxynitrite to in vivo nitration, a O2*- scavenger (MnTBAP; 1 mgxkg-1) was given to C. parvum-primed mice. MnTBAP led to almost complete inhibition of C. parvum-triggered O2*- and peroxynitrite release, whereas nitrite accumulation and formation of 3-nitrotyrosine were less affected ( approximately 50% of controls). These results argue against an essential role of peroxynitrite in protein tyrosine nitration in vivo.
酪氨酸硝化被认为是炎症性疾病中过氧亚硝酸盐引发组织损伤的关键反应。我们研究了过氧亚硝酸盐在分离的小鼠腹腔巨噬细胞蛋白质酪氨酸硝化中的潜在作用，这些巨噬细胞要么在体外经γ-干扰素/脂多糖激活，要么在体内经微小棒状杆菌（10 mg/kg）致敏。两种方案均导致一氧化氮释放和亚硝酸盐积累，并伴有蛋白质结合的3-硝基酪氨酸形成。二氢罗丹明123的氧化是过氧亚硝酸盐释放的一种度量，在体外激活巨噬细胞时其仍接近基础水平，但在体内增加了约两倍。体外激活的巨噬细胞中的酪氨酸硝化受到过氧化氢酶的抑制，硝化的时间进程与亚硝酸盐积累相关，而过氧化物（O2*-）和过氧化氢的释放在更早的时间发生。为了探讨O2*-和过氧亚硝酸盐对体内硝化的作用，给微小棒状杆菌致敏的小鼠注射一种O2*-清除剂（MnTBAP；1 mg/kg）。MnTBAP几乎完全抑制了微小棒状杆菌引发的O2*-和过氧亚硝酸盐释放，而亚硝酸盐积累和3-硝基酪氨酸的形成受到的影响较小（约为对照组的50%）。这些结果表明过氧亚硝酸盐在体内蛋白质酪氨酸硝化中并非起关键作用。
