Overexpression of heme oxygenase-1 in human pulmonary epithelial cells results in cell growth arrest and increased resistance to hyperoxia
Overexpression of heme oxygenase-1 in human pulmonary epithelial cells results in cell growth arrest and increased resistance to hyperoxia
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DOI：
10.1073/pnas.93.19.10393
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发表时间：
1996-09-17
影响因子：
11.1
通讯作者：
Choi, AMK
中科院分区：
文献类型：
--
作者：
Lee, PJ;Alam, J;Choi, AMK
血红素加氧酶（HO）催化血红素降解为胆绿素的限速步骤，胆绿素还原酶将血红素还原为胆红素，血红素加氧酶-1 （HO-1）不仅可被血红素底物诱导，还可被多种引起氧化应激的物质诱导，虽然对HO-1表达的调控已经了解很多，但氧化损伤后HO-1诱导的功能意义尚不清楚。我们假设并提供证据表明，HO-1诱导有助于保护细胞免受氧化应激。稳定转染大鼠HO-1 cDNA的人肺上皮细胞（A549细胞）表现出HO-1 mRNA水平显著升高，与HO酶活性升高相关，过表达HO-1 （A549- a4）的细胞与野生型A549 （A549- wt）细胞或转染对照DNA （A549-neo）的A549细胞相比，细胞生长明显下降。通过对碘化丙啶染色细胞的流式细胞术分析和溴脱氧尿苷脉冲实验发现，这种细胞生长放缓与指数生长期G(0)/G(1)期细胞数量增加和进入S期的细胞数量减少有关。此外，A549-A4细胞在G(2)/M期积累，在血清刺激下无法通过细胞周期。而A549-neo对照细胞表现出正常的细胞周期进程，有趣的是，A549-A4细胞也表现出对高氧氧化损伤的显著抵抗，选择性HO抑制剂锡原卟啉（Tin protoporphyrin）逆转了生长停滞，并消除了在过表达HO-1的A549-A4细胞中观察到的抗高氧生存的增加。综上所述，我们的数据表明，过表达HO-1导致细胞生长停滞。它可以促进细胞保护，防止非血红素介导的氧化性损伤，如高氧。
Heme oxygenase (HO) catalyzes the rate-limiting step in the degradation of heme to biliverdin, which is reduced by biliverdin reductase to bilirubin, Heme oxygenase-1 (HO-1) is inducible not only by its heme substrate, but also by a variety of agents causing oxidative stress, Although much is known about the regulation of HO-1 expression, the functional significance of HO-1 induction after oxidant insult is still poorly understood, We hypothesize and provide evidence that HO-1 induction serves to protect cells against oxidant stress. Human pulmonary epithelial cells (A549 cells) stably transfected with the rat HO-1 cDNA exhibit marked increases of HO-1 mRNA levels which were correlated with increased HO enzyme activity, Cells that overexpress HO-1 (A549-A4) exhibited a marked decrease in cell growth compared with wild-type A549 (A549-WT) cells or A549 cells transfected with control DNA (A549-neo), This slowing of cell growth was associated with an increased number of cells in G(0)/G(1) phase during the exponential growth phase and decreased entry into the S phase, as determined by flow cytometric analysis of propidium iodide-stained cells and pulse experiments with bromodeoxyuridine, Furthermore, the A549-A4 cells accumulated at the G(2)/M phase and failed to progress through the cell cycle when stimulated with serum, whereas the A549-neo control cells exhibited normal cell cycle progression, interestingly, the A549-A4 cells also exhibited marked resistance to hyperoxic oxidant insult, Tin protoporphyrin, a selective inhibitor of HO, reversed the growth arrest and ablated the increased survival against hyperoxia observed in the A549-A4 cells overexpressing HO-1, Taken together, our data suggest that overexpression of HO-1 results in cell growth arrest, which may facilitate cellular protection against non-heme-mediated oxidant insult such as hyperoxia.