Hypoxia inducible factor-1: regulation by nitric oxide in posthypoxic microvascular endothelium
Hypoxia inducible factor-1: regulation by nitric oxide in posthypoxic microvascular endothelium
复制标题
DOI：
10.1139/o05-047
复制
发表时间：
2005-10-01
影响因子：
2.9
通讯作者：
Fowler, AA
中科院分区：
文献类型：
--
作者：
Natarajan, R;Jones, DG;Fowler, AA
微血管内皮细胞在血液成分和组织之间提供关键的调节界面。低氧诱导因子-1（Hypoxia inducible factor-1，HIF-1）是低氧依赖基因表达的关键转录因子。我们采用了缺氧和复氧（H/R）模型，使用真皮微血管内皮细胞系HMEC-1来研究改变氧浓度对微血管HIF-1表达和一氧化氮（NO）形成的影响。缺氧增加诱导型一氧化氮合酶（iNOS）mRNA的时间依赖性的方式在HMEC-1。然而，内皮NO合酶mRNA进行性下降，在缺氧。H/R促进了细胞亚硝酸盐水平的显著增加，而特异性iNOS抑制剂N-6-（1-亚氨基乙基）-L-赖氨酸二盐酸盐显著消除了亚硝酸盐水平。外源性NO促进HIF-1 α亚基的稳定并产生功能性DNA结合。HMEC-1暴露于H/R导致先前未识别的复氧期间的双相HIF-1 α稳定化。当通过使用iNOS特异性小干扰RNA沉默iNOS基因时，HIF-1 α稳定性和HIF-1活化显著降低，表明诱导型NOS衍生的NO是在缺氧和复氧期间维持HIF-1活化的关键因素。
Microvascular endothelial cells provide a critical regulatory interface between blood constituents and tissue. Hypoxia inducible factor-1 (HIF-1) is a key transcription factor required for expression of hypoxia-dependent genes. We employed a model of hypoxia and reoxygenation (H/R) using the dermal microvascular endothelial cell line HMEC-1 to examine the effects of altered oxygen concentrations on rnicrovascular HIF-1 expression and nitric oxide (NO) formation. Hypoxia increased inducible NO synthase (iNOS) mRNA in a time-dependent manner in HMEC-1. However, endothelial NO synthase mRNA progressively declined during hypoxia. H/R promoted significant increases in cellular nitrite levels that were significantly abrogated by the specific iNOS inhibitor N-6-(1-iminoethyl)-L-lysine, dihydrochloride. Exogenous NO promoted stabilization of the alpha subunit of HIF-1 and produced functional DNA binding. Exposure of HMEC-1 to H/R resulted in previously unrecognized biphasic HIF-1 alpha-stabilization during reoxygenation. When the iNOS gene was silenced through the use of iNOS-specific small interfering RNA, HIF-1 alpha stabilization and HIF-1 activation were dramatically diminished, suggesting that inducible NOS-derived NO is a key factor sustaining HIF-1 activation during both hypoxia and reoxygenation.