INSERM U620-EA4427 SeRAIC, IFR140, Université de Rennes I, 2 Avenue du Pr Léon Bernard, 35043 Rennes, France.
Free Radic Biol Med. 2009 Sep 15;47(6):825-34. doi: 10.1016/j.freeradbiomed.2009.06.025. Epub 2009 Jun 24.
Polycyclic aromatic hydrocarbons such as benzo(a)pyrene (BaP) are toxic environmental contaminants known to regulate gene expression through activation of the aryl hydrocarbon receptor (AhR). In the present study, we demonstrated that acute treatment by BaP markedly increased expression of the NADPH oxidase subunit gene neutrophil cytosolic factor 1 (NCF1)/p47(phox) in primary human macrophages; NCF1 was similarly up-regulated in alveolar macrophages from BaP-instilled rats. NCF1 induction in BaP-treated human macrophages was prevented by targeting AhR, through its chemical inhibition or small interference RNA-mediated down-modulation of its expression. BaP moreover induced activity of the NCF1 promoter sequence, containing a consensus AhR-related xenobiotic-responsive element (XRE), and electrophoretic mobility shift assays and chromatin immunoprecipitation experiments indicated that BaP-triggered binding of AhR to this XRE. Finally, we showed that BaP exposure resulted in p47(phox) protein translocation to the plasma membrane and in potentiation of phorbol myristate acetate (PMA)-induced superoxide anion production in macrophages. This BaP priming effect toward NADPH oxidase activity was inhibited by the NADPH oxidase specific inhibitor apocynin and the chemical AhR inhibitor alpha-naphtoflavone. These results indicated that BaP induced NCF1/p47(phox) expression and subsequently enhanced superoxide anion production in PMA-treated human macrophages, in an AhR-dependent manner; such an NCF1/NADPH oxidase regulation by polycyclic aromatic hydrocarbons may participate in deleterious effects toward human health triggered by these environmental contaminants, including atherosclerosis and smoking-related diseases.
多环芳烃如苯并(a)芘（BaP）是有毒的环境污染物，已知通过激活芳烃受体（AhR）来调节基因表达。在本研究中，我们证明 BaP 的急性处理显著增加了原代人巨噬细胞中 NADPH 氧化酶亚基基因中性粒细胞胞质因子 1（NCF1）/p47(phox)的表达；在 BaP 灌注大鼠的肺泡巨噬细胞中，NCF1 也被上调。通过靶向 AhR，通过其化学抑制或小干扰 RNA 介导的表达下调，可防止 BaP 处理的人巨噬细胞中 NCF1 的诱导。此外，BaP 诱导包含共识 AhR 相关外源性反应元件（XRE）的 NCF1 启动子序列的活性，电泳迁移率变动分析和染色质免疫沉淀实验表明，BaP 触发 AhR 与该 XRE 的结合。最后，我们表明 BaP 暴露导致 p47(phox)蛋白易位到质膜，并增强了巨噬细胞中佛波酯（PMA）诱导的超氧阴离子产生。这种 NADPH 氧化酶活性的 BaP 引发效应被 NADPH 氧化酶特异性抑制剂 apocynin 和化学 AhR 抑制剂 alpha-naphtoflavone 抑制。这些结果表明，BaP 以 AhR 依赖的方式诱导 NCF1/p47(phox)表达，随后增强 PMA 处理的人巨噬细胞中超氧阴离子的产生；多环芳烃对 NCF1/NADPH 氧化酶的这种调节可能参与了这些环境污染物对人类健康的有害影响，包括动脉粥样硬化和与吸烟有关的疾病。
