Nitric oxide synthase generates superoxide and nitric oxide in arginine-depleted cells leading to peroxynitrite-mediated cellular injury
Nitric oxide synthase generates superoxide and nitric oxide in arginine-depleted cells leading to peroxynitrite-mediated cellular injury
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DOI：
10.1073/pnas.93.13.6770
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发表时间：
1996-06-25
影响因子：
11.1
通讯作者：
Zweier, JL
中科院分区：
文献类型：
--
作者：
Xia, Y;Dawson, VL;Zweier, JL
纯化的神经型一氧化氮合酶(NNOS)除了能合成一氧化氮(NO)外，还能在较低浓度的L-精氨酸中产生超氧化物歧化酶(O-)。(2)利用电子顺磁共振自旋捕捉技术，我们监测了NO和O-的生成。(2)在nNOS转染人肾293细胞中，钙离子载体A23187触发了NO的生成，但NO-。(2)-，在无L精氨酸的培养液中，我们观察到O-的生成随着细胞内L-精氨酸水平的降低而增加，而NO的生成却减少了。(2)N-硝基-L-精氨酸甲酯(L-NAME)可完全消除O-。(2)-的形成。硝基酪氨酸是过氧亚硝酸根的特异硝化产物，在L精氨酸耗竭细胞中积累，而在对照细胞中不积累。A23187激活对L精氨酸耗竭细胞有细胞毒性，但对对照细胞没有影响，并有明显的乳酸脱氢酶释放，超氧化物歧化酶和L-NAME在很大程度上阻止了这种细胞毒性。因此，随着L-精氨酸可获得性的降低，一氧化氮合酶通过产生O-和NO而引起细胞毒性。(2)-和NO相互作用形成强有力的氧化剂过氧亚硝酸盐。调节精氨酸水平可能为涉及O-。(2)-/NO介导的细胞损伤的疾病提供一种治疗方法。
Besides synthesizing nitric oxide (NO), purified neuronal NO synthase (nNOS) can produce superoxide (O-.(2)-) at lower L-Arg concentrations, By using electron paramagnetic resonance spin-trapping techniques, we monitored NO and O-.(2)- formation in nNOS-transfected human kidney 293 cells, In control transfected cells, the Ca2+ ionophore A23187 triggered NO generation but no O-.(2)- was seen, With cells in L-Arg-free medium, we observed O-.(2)- formation that increased as the cytosolic L-Arg levels decreased, while NO generation declined. O-.(2)- formation was virtually abolished by the specific NOS blocker, N-nitro-L-arginine methyl ester (L-NAME). Nitrotyrosine, a specific nitration product of peroxynitrite, accumulated in L-Arg-depleted cells but not in control cells, Activation by A23187 was cytotoxic to L-Arg-depleted, but not to control cells, with marked lactate dehydrogenase release, The cytotoxicity was largely prevented by either superoxide dismutase or L-NAME. Thus, with reduced L-Arg availability NOS elicits cytotoxicity by generating O-.(2)- and NO that interact to form the potent oxidant peroxynitrite. Regulating arginine levels may provide a therapeutic approach to disorders involving O-.(2)-/NO-mediated cellular injury.