Basic fibroblast growth factor activates endothelial nitric-oxide synthase in CHO-K1 cells via the activation of ceramide synthesis
Basic fibroblast growth factor activates endothelial nitric-oxide synthase in CHO-K1 cells via the activation of ceramide synthesis
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DOI：
10.1124/mol.63.2.297
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发表时间：
2003-02-01
影响因子：
3.6
通讯作者：
Schettini, G
中科院分区：
文献类型：
--
作者：
Florio, T;Arena, S;Schettini, G
在这项研究中，我们分析了细胞内的机制，导致碱性成纤维细胞生长因子（bFGF）依赖的生产NO在中国仓鼠卵巢（CHO）-K1细胞和可能的生理作用，这样的效果。bFGF通过激活内皮形式的NO合酶（eNOS）诱导NO产生，导致随后cGMP水平的增加。在这些细胞中，bFGF激活eNOS是Ca 2+和丝裂原活化蛋白激酶独立的。从质膜，在那里它是位于结合小窝蛋白1的小窝，到胞质溶胶的酶的易位是通过eNOS亚型的NO的合成的关键步骤。我们表明，碱性成纤维细胞生长因子激活鞘磷脂酶合成神经酰胺，这反过来，允许eNOS从小窝蛋白1和其易位的细胞质中的活性形式，在那里它催化NO的合成的解离。事实上，药物干扰鞘磷脂酶活性阻断bFGF激活eNOS，和神经酰胺含量的增加后，检测到碱性成纤维细胞生长因子治疗。此外，在来自尼曼-匹克病患者的成纤维细胞中，bFGF不能引起eNOS活化，其中酶在遗传上是失活的。bFGF处理后产生的NO，通过鸟苷酸环化酶和蛋白激酶G的激活，介导了一个丝裂原活化蛋白激酶非依赖性细胞增殖。总之，我们的数据表明，在CHO-K1细胞中，bFGF调节eNOS的活性，通过一种新的细胞内途径，涉及神经酰胺合成的诱导和释放的NO参与bFGF的增殖活性。
In this study, we analyzed the intracellular mechanisms leading to basic fibroblast growth factor (bFGF)-dependent production of NO in Chinese hamster ovary (CHO)-K1 cells and a possible physiological role for such an effect. bFGF induces NO production through the activation of the endothelial form of NO synthase (eNOS), causing a subsequent increase in the cGMP levels. In these cells, the activation of eNOS by bFGF is Ca2+- and mitogen-activated protein kinase-independent. The translocation of the enzyme from the plasma membrane, where it is located in caveolae bound to caveolin 1, to the cytosol is the crucial step for the synthesis of NO through the eNOS isoform. We demonstrate that bFGF activates a sphingomyelinase to synthesize ceramide, which, in turn, allows the dissociation of eNOS from caveolin 1 and its translocation to the cytosol in the active form, where it catalyzes the synthesis of NO. In fact, drugs interfering with sphingomyelinase activity blocked bFGF activation of eNOS, and an increase in ceramide content was detected after bFGF treatment. Moreover, in fibroblasts derived from patients with Niemann-Pick disease, in which the enzyme is genetically inactive, bFGF is unable to elicit eNOS activation. The NO produced after bFGF treatment, through the activation of guanylyl cyclase and protein kinase G, mediates a mitogen-activated protein kinase-independent cell proliferation. In conclusion, our data show that, in CHO-K1 cells, bFGF regulates the activity of eNOS through a novel intracellular pathway, involving the induction of ceramide synthesis and that the NO released participates in bFGF proliferative activity.