A Prolyl-hydroxylase Inhibitor, Ethyl-3,4-dihydroxybenzoate, Induces Haem Oxygenase-1 Expression in Human Cells Through a Mechanism Independent of Hypoxia-inducible Factor-1α
A Prolyl-hydroxylase Inhibitor, Ethyl-3,4-dihydroxybenzoate, Induces Haem Oxygenase-1 Expression in Human Cells Through a Mechanism Independent of Hypoxia-inducible Factor-1α
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DOI：
10.1093/jb/mvn115
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发表时间：
2008-11-01
影响因子：
2.7
通讯作者：
Shibahara, Shigeki
中科院分区：
文献类型：
--
作者：
Li, Bin;Takeda, Kazuhisa;Shibahara, Shigeki
缺氧诱导因子（HIF）-1对于缺氧条件下的细胞稳态非常重要。血红素加氧酶-1（HO-1）是血红素细胞中的一种重要酶，其表达在缺氧条件下因细胞类型而异。在这里，我们研究了HIF-1 α，HIF-1的一个组成部分，在调节HO-1的表达，使用三种人类细胞系：HeLa宫颈癌，ARPE-19和D407视网膜色素上皮细胞。低氧（1%O（2））条件下，HeLa细胞HO-1 mRNA表达降低，D407细胞HO-1 mRNA表达升高，ARPE-19细胞HO-1 mRNA表达无明显变化，而HIF-1 α蛋白在上述细胞系中均有表达。因此，HIF-1 α不太可能在缺氧条件下作为HO-1表达的关键调节因子发挥作用。然后，我们使用3，4-二羟基苯甲酸乙酯（EDHB），脯氨酰羟化酶的抑制剂，在常氧下积累HIF-1 α蛋白。用EDHB（250-500 μ M）处理增加HeLa和D407细胞中的HIF-1 α蛋白水平，但不增加ARPE-19细胞中的HIF-1 α蛋白水平，而较低浓度（50-100 μ M）的EDHB在这三种细胞系中持续诱导HO-1 mRNA表达（约20倍）。此外，EDHB通过缺乏HIF-1结合位点的增强子增加HO-1基因启动子活性。总之，缺氧和EDHB治疗后引起的信号通过HIF-1 α非依赖性机制差异调节HO-1 mRNA表达。
Hypoxia-inducible factor (HIF)-1 is important for cellular homeostasis under hypoxia. Expression of haem oxygenase-1 (HO-1), an essential enzyme in haem catabolism, varies under hypoxia, depending on cell types. Here, we studied the role of HIF-1 alpha, a component of HIF-1, in the regulation of HO-1 expression using three human cell lines: HeLa cervical cancer, and ARPE-19 and D407 retinal pigment epithelial cells. Under hypoxia (1% O(2)), the expression of HO-1 mRNA was decreased in HeLa cells, increased in D407 cells, and unchanged in ARPE-19 cells, while HIF-1 alpha protein was accumulated in these cell lines. Thus, HIF-1 alpha is unlikely to function as a key regulator for HO-1 expression under hypoxia. We then used ethyl-3,4-dihydroxybenzoate (EDHB), an inhibitor of prolyl hydroxylases, to accumulate HIF-1 alpha protein under normoxia. Treatment with EDHB (250-500 mu M) increased HIF-1 alpha protein levels in HeLa and D407 cells, but not in ARPE-19 cells, whereas EDHB at lower concentrations (50-100 mu M) consistently induced HO-1 mRNA expression (about 20-fold) in these three cell lines. Moreover, EDHB increased the HO-1 gene promoter activity via the enhancer that lacks a HIF-1-binding site. In conclusion, the signals evoked by hypoxia and after EDHB treatment differentially regulate HO-1 mRNA expression through HIF-1 alpha-independent mechanisms.