Gallate, the component of HIF-inducing catechins, inhibits HIF prolyl hydroxylase.
Gallate, the component of HIF-inducing catechins, inhibits HIF prolyl hydroxylase.
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DOI：
10.1016/j.bbrc.2006.10.025
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发表时间：
2006-12
影响因子：
3.1
通讯作者：
F. Tsukiyama;Y. Nakai;Masataka Yoshida;T. Tokuhara;K. Hirota;Akiko Sakai;H. Hayashi;T. Katsumata
中科院分区：
文献类型：
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作者：
F. Tsukiyama;Y. Nakai;Masataka Yoshida;T. Tokuhara;K. Hirota;Akiko Sakai;H. Hayashi;T. Katsumata
最近有报道儿茶素可增加哺乳动物细胞内缺氧诱导因子（HIF）-1α的含量。这些儿茶素具有没食子酸酯部分作为共同结构。我们现在报道，没食子酸正丙酯（nPG）也增加了大鼠心脏来源的H9 c2细胞中的HIF-1α蛋白。这种增加是剂量依赖性的，并在加入nPG后2- 4 h达到最大值。nPG没有改变HIF-1α mRNA水平，表明增加是转录后事件。虽然nPG没有抑制HIF脯氨酰羟化酶，没食子酸，nPG的水解产物，抑制酶完全在亚毫摩尔浓度。对人HIF脯氨酰羟化酶2的建模研究表明，没食子酸酯的两个酚氧原子与活性位点Fe 2+形成螯合物，而没食子酸酯的羧基与Arg 383形成强离子/氢键相互作用，这解释了为什么具有酯化羧基的nPG不能抑制羟化酶。结合在用nPG处理的H9 c2细胞中检测到没食子酸的观察结果，这些结果表明掺入细胞中的nPG被水解，释放的没食子酸抑制HIF脯氨酰羟化酶，从而降低HIF降解速率并增加HIF-1α含量。
Catechins have recently been reported to increase the cellular content of the hypoxia-inducible factor (HIF)-1α within mammalian cells. These catechins have a gallate moiety as a common structure. We now report that n-propyl gallate (nPG) also increases the HIF-1α protein in the rat heart-derived H9c2 cells. The increase was dose-dependent and reached a maximum at 2–4h after the addition of nPG to the cells. nPG did not change the HIF-1α mRNA level, showing that the increase is a posttranscriptional event. Although nPG did not inhibit the HIF prolyl hydroxylase, gallate, the hydrolysis product of nPG, inhibited the enzyme completely at submillimolar concentrations. Model building studies on the human HIF prolyl hydroxylase 2 showed that the two phenolate oxygen atoms of gallate form a chelate with the active site Fe2+, while the carboxyl group of gallate forms a strong ionic/hydrogen bonding interaction with Arg383, explaining why nPG, which has an esterified carboxyl group, is unable to inhibit the hydroxylase. Together with the observation that gallate was detected in the H9c2 cells treated with nPG, these results suggest that nPG incorporated into the cells is hydrolyzed and the released gallate inhibits the HIF prolyl hydroxylase, thereby reducing the HIF degradation rate and increasing the HIF-1α content.