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Relation between dysfunction of nitric oxide synthase and angiogenesis

一氧化氮合酶功能障碍与血管生成的关系

基本信息

批准号：
09672334
负责人：
MOMOSE Kazutaka
金额：
$ 1.54万
依托单位：
Showa University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

项目摘要

Reactive oxygen species (ROS) have been known to induce tissue injury in ischemialreperfusion and inflammation. Recently, however, it has beenTeported that-ROS regulates cel-lular-function such as proliferation. Interestingly, nitric oxide synthase (NOS) from brain releases ROS instead of nitric oxide (NO) when tetrahydrobiopterin (BH4), a cofactor of NOS, is decreased. The purpose of this study was to determine whether endothelial isoform of NOS also produces ROS with decreasing BH4, and the dysfunction of NOS affects angiogenesis. Addition of calcium ionophore to endothelial cells (ECs) released 0_2 which was measured by using MCLA, a Cypridina luciferin analogue. The calcium ionophore-induced 0_2 release was further stimulated by the treatment with 2,4-diamino-6-hydroxyprimidine (DAHP), an inhibitor of BH4 synthesis. Moreover, he calcium ionophore-induced O_2 release in the DAHP treated cells was strongly inhibited by NOS inhibitor. These findings suggest that endothelial isoform of NOS also produces ROS with decreasing BH4 content. We next examined the effect of H_20_2, one of the ROS, on in vitro angiogenesis. The low concentrations of H_20 stimulated angiogenesis. Ets-1 is a member of the ets gene family of transcription factors, which regulates the expression of urokinase plasminogen activator and matrix metalloprotease-1. Interestingly, H_20_2, increased the ets-l mRNA in ECs. The H_2_2-stimulated angiogenesis was completely blocked by an ets-1 antisense oligonucleotide. These results indicate that low concentrations of H_2O_2 stimulate angiogenesis, and the H_20_2-induced angiogenesis is likely to be mediated by the transcription factor ets-l. In the present study, we were not able to determine whether ROS from NOS affect angiogenesis, since DAHP itself has an inhibiting effect of angiogenesis. Future studies will be needed to find more selective inhibitor for BH4 synthesis.

活性氧（Reactive oxygen species，ROS）在缺血再灌注损伤和炎症反应中起重要作用.然而，最近的研究表明，-ROS调节细胞的功能，如增殖。有趣的是，当NOS的辅因子四氢生物蝶呤（BH 4）减少时，脑中的一氧化氮合酶（NOS）释放ROS而不是一氧化氮（NO）。本研究的目的是确定是否内皮型NOS也产生ROS与减少BH 4，NOS功能障碍影响血管生成。加入钙离子载体的内皮细胞（ECs）释放O_2，这是通过使用MCLA，Cypridina alcohol in类似物测量。BH_4合成抑制剂2，4-二氨基-6-羟基嘧啶（DAHP）可进一步促进钙离子载体诱导的O_2释放。NOS抑制剂可明显抑制DAHP诱导的细胞O_2释放。这些发现表明，内皮型NOS也产生ROS与减少BH 4含量。我们接下来检查了H_2O_2（ROS之一）对体外血管生成的影响。低浓度H_20刺激血管生成。Ets-1是ets基因转录因子家族的成员，调节尿激酶纤溶酶原激活物和基质金属蛋白酶-1的表达。有趣的是，H_2O_2增加了EC中ets-lmRNA的表达。ets-1反义寡核苷酸可完全阻断H_2_2诱导的血管生成。这些结果表明，低浓度H_2O_2刺激血管生成，H_2O_2诱导的血管生成可能是由转录因子ets-1介导的。在本研究中，我们不能确定来自NOS的ROS是否影响血管生成，因为DAHP本身具有抑制血管生成的作用。未来的研究将需要找到更有选择性的BH 4合成抑制剂。