Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230601, China; Institute of Respiratory Diseases, Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230601, China.
Department of Respiratory and Critical Care Medicine, Second Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230601, China; Department of Respiratory and Critical Care Medicine, Chengdu Fifth People's Hospital, Chengdu, Sichuan 611130, China.
J Hazard Mater. 2024 Jul 15;473:134560. doi: 10.1016/j.jhazmat.2024.134560. Epub 2024 May 8.
Benzo[a]pyrene (BaP) and its metabolic end product benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide (BPDE), are known toxic environmental pollutants. This study aimed to analyze whether sub-chronic BPDE exposure initiated pulmonary fibrosis and the potential mechanisms. In this work, male C57BL6/J mice were exposed to BPDE by dynamic inhalation exposure for 8 weeks. Our results indicated that sub-chronic BPDE exposure evoked pulmonary fibrosis and epithelial-mesenchymal transition (EMT) in mice. Both in vivo and in vitro, BPDE exposure promoted nuclear translocation of Snail. Further experiments indicated that nuclear factor erythroid 2-related factor 2 (Nrf2) and p62 were upregulated in BPDE-exposed alveolar epithelial cells. Moreover, Nrf2 siRNA transfection evidently attenuated BPDE-induced p62 upregulation. Besides, p62 shRNA inhibited BPDE-incurred Snail nuclear translocation and EMT. Mechanically, BPDE facilitated physical interaction between p62 and Snail in the nucleus, then repressed Snail protein degradation by p62-dependent autophagy-lysosome pathway, and finally upregulated transcriptional activity of Snail. Additionally, aryl hydrocarbon receptor (AhR) was activated in BPDE-treated alveolar epithelial cells. Dual-luciferase assay indicated activating AhR could bind to Nrf2 gene promoter. Moreover, pretreatment with CH223191 or α-naphthoflavone (α-NF), AhR antagonists, inhibited BPDE-activated Nrf2-p62 signaling, and alleviated BPDE-induced EMT and pulmonary fibrosis in mice. Taken together, AhR-mediated Nrf2-p62 signaling contributes to BaP-induced EMT and pulmonary fibrosis.
苯并[a]芘（BaP）及其代谢终产物苯并[a]芘-7,8-二氢二醇-9,10-环氧化物（BPDE）是已知的有毒环境污染物。本研究旨在分析亚慢性 BPDE 暴露是否引发肺纤维化及其潜在机制。在这项工作中，雄性 C57BL6/J 小鼠通过动态吸入暴露于 BPDE 8 周。我们的结果表明，亚慢性 BPDE 暴露可诱发小鼠肺纤维化和上皮-间充质转化（EMT）。体内和体外实验均表明，BPDE 暴露促进了 Snail 的核转位。进一步的实验表明，BPDE 暴露的肺泡上皮细胞中核因子红细胞 2 相关因子 2（Nrf2）和 p62 上调。此外，Nrf2 siRNA 转染可明显减弱 BPDE 诱导的 p62 上调。此外，p62 shRNA 抑制 BPDE 诱导的 Snail 核转位和 EMT。机制上，BPDE 促进了 p62 和 Snail 在核内的物理相互作用，然后通过 p62 依赖的自噬溶酶体途径抑制 Snail 蛋白降解，最终上调了 Snail 的转录活性。此外，BPDE 处理的肺泡上皮细胞中激活了芳香烃受体（AhR）。双荧光素酶报告基因检测表明，激活的 AhR 可以结合到 Nrf2 基因启动子上。此外，用 AhR 拮抗剂 CH223191 或α-萘黄酮（α-NF）预处理可抑制 BPDE 激活的 Nrf2-p62 信号通路，并减轻 BPDE 诱导的 EMT 和小鼠肺纤维化。综上所述，AhR 介导的 Nrf2-p62 信号通路参与了 BaP 诱导的 EMT 和肺纤维化。
