红细胞生成素3'-增强子片段对内皮细胞缺氧时环加氧酶-2基因表达的影响

目的和方法：体外合成红细胞生成素（Ｅｐｏ）３′－增强子野生型及突变型片段，借助脂质体，转入内皮细胞，用半定量ＲＴ－ＰＣＲ方法测定分离细胞在常氧或缺氧条件下培养４ｈ的环加氧酶２（ＣＯＸ－２）ｍＲＮＡ。结果：（１）大鼠主动脉内皮细胞、肺微血管内皮细胞在常氧下培养，有ＣＯＸ－２基因表达；（２）缺氧能诱导这两种细胞ＣＯＸ－２基因表达增加；（３）野生型Ｅｐｏ３′－增强子片段能阻断缺氧对内皮细胞ＣＯＸ－２基因表达的诱导作用，而突变片段则无此作用。结论：在ＣＯＸ－２基因序列中，可能存在Ｅｐｏ３′－端增强子片段，它参与了内皮细胞的缺氧反应

Effects of erythropoietin 3' (Epo3') -enhancer fragments on the hypoxia induced expression of cyclooxygenase-2 (COX-2) gene in endothelial cells

AIM and METHODS:Wild and mutant Epo 3'-enchancer DNA fragments were synthesized in vitro . Cultured endothelial cells were transfected by wild or mutant fragments. Total RNA was extracted from endothelial cells exposed to normoxia or hypoxia for 4h. The amount of COX-2 mRNA was measured by semiquantitative RT-PCR. RESULTS:1. There was expression of COX-2 gene in both aortic endothelial cells and pulmonary vascular endothelial cells in normoxia. 2. Hypoxia increased COX-2 gene expression in these two kinds of endothelial cells. 3. The wild Epo 3'-enchaner fragments inhibited the hypoxia-induced expression of COX-2 gene, whereas the mutant sequence did not. CONCLUSION:The increase of COX-2 expression in hypoxia might result from the combination of activated hypoxia inducible factor -1 with Epo 3'-enhancer-like sequence in COX-2 gene.