Suvorava Tatsiana, Nagy Nadine, Pick Stephanie, Lieven Oliver, Rüther Ulrich, Dao Vu Thao-Vi, Fischer Jens W, Weber Martina, Kojda Georg
1 Institute for Pharmacology and Clinical Pharmacology, Heinrich-Heine-University , Düsseldorf, Germany .
2 Institute for Animal Developmental and Molecular Biology, Heinrich-Heine-University , Düsseldorf, Germany .
Antioxid Redox Signal. 2015 Sep 20;23(9):711-23. doi: 10.1089/ars.2014.6059. Epub 2015 Jun 8.
Vascular oxidative stress generated by endothelial NO synthase (eNOS) was observed in experimental and clinical cardiovascular disease, but its relative importance for vascular pathologies is unclear. We investigated the impact of eNOS-dependent vascular oxidative stress on endothelial function and on neointimal hyperplasia.
A dimer-destabilized mutant of bovine eNOS where cysteine 101 was replaced by alanine was cloned and introduced into an eNOS-deficient mouse strain (eNOS-KO) in an endothelial-specific manner. Destabilization of mutant eNOS in cells and eNOS-KO was confirmed by the reduced dimer/monomer ratio. Purified mutant eNOS and transfected cells generated less citrulline and NO, respectively, while superoxide generation was enhanced. In eNOS-KO, introduction of mutant eNOS caused a 2.3-3.7-fold increase in superoxide and peroxynitrite formation in the aorta and myocardium. This was completely blunted by an NOS inhibitor. Nevertheless, expression of mutant eNOS in eNOS-KO completely restored maximal aortic endothelium-dependent relaxation to acetylcholine. Neointimal hyperplasia induced by carotid binding was much larger in eNOS-KO than in mutant eNOS-KO and C57BL/6, while the latter strains showed comparable hyperplasia. Likewise, vascular remodeling was blunted in eNOS-KO only.
Our results provide the first in vivo evidence that eNOS-dependent oxidative stress is unlikely to be an initial cause of impaired endothelium-dependent vasodilation and/or a pathologic factor promoting intimal hyperplasia. These findings highlight the importance of other sources of vascular oxidative stress in cardiovascular disease.
eNOS-dependent oxidative stress is unlikely to induce functional vascular damage as long as concomitant generation of NO is preserved. This underlines the importance of current and new therapeutic strategies in improving endothelial NO generation.
在实验性和临床心血管疾病中均观察到内皮型一氧化氮合酶（eNOS）产生的血管氧化应激，但尚不清楚其在血管病变中的相对重要性。我们研究了eNOS依赖性血管氧化应激对内皮功能和内膜增生的影响。
克隆了牛eNOS的二聚体不稳定突变体，其中半胱氨酸101被丙氨酸取代，并以内皮特异性方式导入eNOS缺陷小鼠品系（eNOS-KO）。通过降低的二聚体/单体比率证实了细胞和eNOS-KO中突变体eNOS的不稳定。纯化的突变体eNOS和转染的细胞分别产生较少的瓜氨酸和一氧化氮，而超氧化物的产生增加。在eNOS-KO中，引入突变体eNOS导致主动脉和心肌中超氧化物和过氧亚硝酸盐形成增加2.3至3.7倍。这被一氧化氮合酶抑制剂完全抑制。然而，在eNOS-KO中突变体eNOS的表达完全恢复了主动脉对乙酰胆碱的最大内皮依赖性舒张。颈动脉结扎诱导的内膜增生在eNOS-KO中比在突变体eNOS-KO和C57BL/6中要大得多，而后两种品系显示出相当的增生。同样，血管重塑仅在eNOS-KO中受到抑制。
我们的结果提供了首个体内证据，表明eNOS依赖性氧化应激不太可能是内皮依赖性血管舒张受损的初始原因和/或促进内膜增生的病理因素。这些发现突出了心血管疾病中其他血管氧化应激来源的重要性。
只要保留一氧化氮的伴随生成，eNOS依赖性氧化应激不太可能诱导功能性血管损伤。这强调了当前和新治疗策略在改善内皮一氧化氮生成方面的重要性。
