Schroedl Clara, McClintock David S, Budinger G R Scott, Chandel Navdeep S
Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
Am J Physiol Lung Cell Mol Physiol. 2002 Nov;283(5):L922-31. doi: 10.1152/ajplung.00014.2002.
The molecular mechanisms by which cells detect hypoxia (1.5% O2), resulting in the stabilization of hypoxia-inducible factor 1alpha (HIF-1alpha) protein remain unclear. One model proposes that mitochondrial generation of reactive oxygen species is required to stabilize HIF-1alpha protein. Primary evidence for this model comes from the observation that cells treated with complex I inhibitors, such as rotenone, or cells that lack mitochondrial DNA (rho(0)-cells) fail to generate reactive oxygen species or stabilize HIF-1alpha protein in response to hypoxia. In the present study, we investigated the role of mitochondria in regulating HIF-1alpha protein stabilization under anoxia (0% O2). Wild-type A549 and HT1080 cells stabilized HIF-1alpha protein in response to hypoxia and anoxia. The rho(0)-A549 cells and rho(0)-HT1080 cells failed to accumulate HIF-1alpha protein in response to hypoxia. However, both rho(0)-A549 and rho(0)-HT1080 were able to stabilize HIF-1alpha protein levels in response to anoxia. Rotenone inhibited hypoxic, but not anoxic, stabilization of HIF-1alpha protein. These results indicate that a functional electron transport chain is required for hypoxic but not anoxic stabilization of HIF-1alpha protein.
细胞检测低氧（1.5% O₂）从而导致低氧诱导因子1α（HIF-1α）蛋白稳定的分子机制仍不清楚。一种模型认为，活性氧的线粒体生成是稳定HIF-1α蛋白所必需的。该模型的主要证据来自以下观察结果：用复合物I抑制剂（如鱼藤酮）处理的细胞，或缺乏线粒体DNA的细胞（ρ⁰细胞），在低氧刺激下无法产生活性氧或稳定HIF-1α蛋白。在本研究中，我们研究了线粒体在缺氧（0% O₂）条件下调节HIF-1α蛋白稳定中的作用。野生型A549和HT1080细胞在低氧和缺氧刺激下稳定HIF-1α蛋白。ρ⁰-A549细胞和ρ⁰-HT1080细胞在低氧刺激下无法积累HIF-1α蛋白。然而，ρ⁰-A549和ρ⁰-HT1080细胞在缺氧刺激下均能稳定HIF-1α蛋白水平。鱼藤酮抑制低氧而非缺氧条件下HIF-1α蛋白的稳定。这些结果表明，功能性电子传递链是低氧而非缺氧条件下稳定HIF-1α蛋白所必需的。
