Resistance to endotoxic shock in endothelial nitric-oxide synthase (eNOS) knock-out mice -: A pro-inflammatory role for eNOS-derived no in vivo
Resistance to endotoxic shock in endothelial nitric-oxide synthase (eNOS) knock-out mice -: A pro-inflammatory role for eNOS-derived no in vivo
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DOI：
10.1074/jbc.m411991200
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发表时间：
2005-03-18
影响因子：
4.8
通讯作者：
Hobbs, AJ
中科院分区：
文献类型：
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作者：
Connelly, L;Madhani, M;Hobbs, AJ
诱导型一氧化氮合酶(INOS)的表达和随后的“高输出”一氧化氮(NO)的产生是感染性休克相关的全身低血压、组织灌流不足和器官衰竭的基础。因此，内源性和外源性iNOS表达和活性的调节因子在决定这种情况的大小和时间过程中非常重要。我们以前已经证明，在小鼠巨噬细胞暴露于脂多糖(LPS)后，来自内皮型一氧化氮合酶(ENOS)的NO是获得最大iNOS表达和活性所必需的。因此，eNOS是体外诱导型一氧化氮合酶表达的重要调节因子。在这里，我们使用脓毒症的小鼠模型在体内验证了这一假设。与野生型动物相比，内毒素治疗的eNOS基因敲除(KO)小鼠的iNOS表达和活性在时间上降低；这反映在内毒素血症期间eNOS KO小鼠更稳定的血流动力学特征。此外，在人脐静脉内皮细胞中，内毒素通过磷酸肌醇3-激酶和Akt/蛋白激酶B依赖的酶的磷酸化导致eNOS的激活。这些数据表明，脓毒症的发病机制是以eNOS的初始激活为特征的，所产生的NO作为iNOS表达的共同刺激，从而突出了eNOS的新的促炎作用。
The expression of inducible nitric-oxide synthase (iNOS) and subsequent "high-output" nitric oxide (NO) production underlies the systemic hypotension, inadequate tissue perfusion, and organ failure associated with septic shock. Therefore, modulators of iNOS expression and activity, both endogenous and exogenous, are important in determining the magnitude and time course of this condition. We have shown previously that NO from the constitutive endothelial NOS (eNOS) is necessary to obtain maximal iNOS expression and activity following exposure of murine macrophages to lipopolysaccharide (LPS). Thus, eNOS represents an important regulator of iNOS expression in vitro. Herein, we validate this hypothesis in vivo using a murine model of sepsis. A temporal reduction in iNOS expression and activity was observed in LPS-treated eNOS knock-out (KO) mice as compared with wild-type animals; this was reflected in a more stable hemodynamic profile in eNOS KO mice during endotoxaemia. Furthermore, in human umbilical vein endothelial cells, LPS leads to the activation of eNOS through phosphoinositide 3-kinase- and Akt/protein kinase B-dependent enzyme phosphorylation. These data indicate that the pathogenesis of sepsis is characterized by an initial eNOS activation, with the resultant NO acting as a co-stimulus for the expression of iNOS, and therefore highlight a novel pro-inflammatory role for eNOS.