Activation of the endothelial nitric-oxide synthase by tumor necrosis factor-α -: A novel feedback mechanism regulating cell death
Activation of the endothelial nitric-oxide synthase by tumor necrosis factor-α -: A novel feedback mechanism regulating cell death
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DOI：
10.1074/jbc.m006535200
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发表时间：
2001-03-02
影响因子：
4.8
通讯作者：
Clementi, E
中科院分区：
文献类型：
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作者：
Bulotta, S;Barsacchi, R;Clementi, E
肿瘤坏死因子-α (TNF-α) 诱导的细胞凋亡导致的细胞死亡在许多生理和病理条件下发挥着重要作用。已知由该细胞因子激活的信号转导途径受到几种细胞内信使的调节。特别是，在许多系统中，一氧化氮 (NO) 已被证明可以保护细胞免受 TNF-α 诱导的细胞凋亡。然而，细胞因子是否可以产生NO来下调其自身的细胞凋亡程序尚未被研究。我们已经在四环素响应启动子下用内皮 NO 合酶稳定转染的 HeLa Tet-off 细胞克隆中解决了这个问题。通过去除抗生素，这些细胞中的内皮NO合酶被诱导约100倍，在细胞内定位和功能活性方面保留了内皮细胞天然酶的特征。内皮NO合酶的表达足以防止TNF-α诱导的细胞凋亡。这种保护是由 NO 的产生介导的。 TNF-α本身刺激内皮NO合酶活性，通过涉及其脂质信使神经酰胺的途径产生NO。我们的结果确定了一种由死亡受体激活的信号转导途径调节的新机制，并表明 NO 可能构成 TNF-α 控制其自身细胞凋亡程序的内在机制。
Cell death via apoptosis induced by tumor necrosis factor-alpha (TNF-alpha) plays an important role in many physiological and pathological conditions. The signal transduction pathway activated by this cytokine is known to be regulated by several intracellular messengers. In particular, in many systems nitric oxide (NO) has been shown to protect cells from TNF-alpha -induced apoptosis. However, whether NO can be generated by the cytokine to down-regulate its own apoptotic program has never been studied. We have addressed this question in HeLa Tet-off cell clones stably transfected with the endothelial NO synthase under a tetracycline-responsive promoter. Endothelial NO synthase, induced about 100-fold in these cells by removal of the antibiotic, retained the characteristics of the native enzyme of endothelial cells, both in terms of intracellular localization and functional activity. Expression of the endothelial NO synthase was sufficient to protect from TNF-alpha -induced apoptosis. This protection was mediated by the generation of NO. TNF-alpha itself stimulated endothelial NO synthase activity to generate NO through a pathway involving its lipid messenger, ceramide. Our results identify a novel mechanism of regulation of a signal transduction pathway activated by death receptors and suggest that NO may constitute a built-in mechanism by which TNF-alpha controls its own apoptotic program.