缺氧诱导因子-1和红细胞生成素3′-增强子调节内皮细胞环氧合酶和血栓素合酶基因转录

HYPOXIA INDUCIBLE FACTOR-1 AND ERYTHROPOIETIN 3′-ENHANCER REGULATE GENE TRANSCRIPTION OF CYCLOOXYGENASE AND THROMBOXANE SYNTHASE IN ENDOTHELIAL CELLS

目的和方法 :将红细胞生成素 (EPO) 3′ 增强子野生片断及点突变片断借脂质体转入人脐静脉内皮细胞株ECV 30 4,用半定量RT PCR测定正常与缺氧诱导因子 1 (HIF 1 )诱导剂氯化钴 (CoCl2 )作用下培养 6h的细胞环氧合酶 2 (COX 2 )和血栓素合酶 (TXS)的mRNA。结果 :HIF 1诱导剂CoCl2 可诱导ECV 30 4的COX 2和TXS基因转录明显增强 ;向细胞导入野生EPO3′增强子片断可阻断CoCl2 诱导的COX 2和TXS基因转录增强 ,而点突变片断无此作用。结论 :在COX 2和TXS基因序列中 ,可能存在EPO3′ 增强子类似片断中的HIF 1的结合序列 ,HIF 1诱导COX 2和TXS基因表达增强可能主要通过HIF 1与该序列结合实现的。

Aim and Methods:Wild or spot mutant of erythropoietin(EPO)3′ enhancer fragments were synthesized in vitro and transfected into cultured human umbilical vein endothelial cell line ECV 304.Total RNA was extracted from ECV 304 cells exposed to normal or cobalt chloride, an inducer of hypoxia inducible factor 1 (HIF 1), for 6 hours. COX 2 and TXS mRNA were measured by semiquantitation RT PCR. Results:COX 2 and TXS mRNAs were increased in ECV 304 cells exposed to CoCl 2.which could be inhibited by the transfection of the wild EPO 3′ enhancer fragment but not by the mutant one. Conclusion:It is suggested that the COX 2 and TXS gene might contain sequences similar to the HIF 1 binding site in the EPO 3′ enhancer, which in combination with hypoxia induced factor 1 might contribute to the increase of COX 2 and TXS mRNA induced by CoCl 2.