缺氧时肺动脉平滑肌Kv亚型的表达及缺氧诱导因子-1在其中的作用

The expression of sub-Kv in pulmonary artery smooth muscle when hypoxia and the influence of hypoxia-inducible factor-1 (HIF-1) within it.

目的探讨缺氧对培养的大鼠肺动脉平滑肌细胞(PASMCs)上Kv3.1、Kv4.2基因转录的影响及缺氧诱导因子-1(HIF-1)和红细胞生成素(EPO)3′端增强子在其中的作用。方法体外合成EPO3′端增强子野生型和突变型片段,借助脂质体转入PASMCs,用RT-PCR法测定细胞在常氧或缺氧条件下培养18h的Kv3.1和Kv4.2的mRNA。结果缺氧18h能增加Kv3.1和Kv4.2基因转录。转入野生型EPO3′端增强子片段后,能消除缺氧时Kv3.1、Kv4.2基因转录的增加,而转入突变型片段则无此作用。结论缺氧有增加PASMCs上Kv3.1、Kv4.2基因转录的作用,该作用受到HIF-1的调制,且在Kv3.1、Kv4.2基因的调控序列中,可能存在与EPO3′端增强子片段相似的序列。

Objective To investigate the effect of hypoxia on the gene transcription of Kv3. 1, Kv4. 2 in the pulmonary artery smooth muscle cells and the influence of hypoxia-inducible factor-1 （HIF-1） and erythropoietin（EPO） 3＇ -enhancer within it. Methods Wild and mutant EPO3＇-enhancer DNA fragments were synthesized in viro. Cultured PASMCs were transfected by wild or mutant fragments. Total RNA was extracted from PASMCs exposed to normoxia or hypoxia forlSh. The amount of Kv3. 1 and Kv4. 2 mRNA was measured by RT-PCR. Results Hypoxia for 18h increased Kv3. 1, Kv4. 2 gene transcription; the wild EPO3＇-enhancer fragments inhibited the hypoxia-induced gene transcription of Kv3. 1 and Kv4. 2, whereas the mutantsequence did not. Conclusion Hypoxia has the ability of increasing the gene transcription of Kv3. 1, Kv4. 2 in PASMCs, and this effect may be regulated by HIF-1, there may be EPO3 ＇-enhancer-hke sequence in the regulating domain of these two genes.