The Department of Occupational and Environmental Health, School of Public Health, Ningxia Medical University, 1160 Shengli Street, Xingqing District, Yinchuan, 750004, People's Republic of China.
Environ Toxicol. 2016 Nov;31(11):1407-1414. doi: 10.1002/tox.22146. Epub 2015 Apr 15.
Epithelial-mesenchymal transition (EMT) is believed to be involved in lung fibrosis process induced by paraquat (PQ); however, the molecular mechanism of this process has not been clearly established. The present study investigated the potential involvement of EMT after PQ poisoning. The expressions of EMT markers, such as E-cadherin and α-smooth muscle actin (α-SMA), at multiple time points after exposure to different concentrations of PQ were evaluated by western blot analysis. Following PQ treatment, EMT induction was observed under microscopy. Related fibrosis genes, including Matrix metalloproteinase 2 (MMP-2), Matrix metalloproteinase 9 (MMP-9), collagens type I (COL I), and type III (COL III), were also evaluated by measuring their mRNA levels using RT-PCR analysis. Signaling pathways were analyzed using selective pharmacological inhibitors for MAPK. Cell migration ability was evaluated by scratch wound and Transwell assays. The data showed that PQ-induced epithelial RLE-6NT cells to develop mesenchymal cell characteristics, as indicated by a significant decrease in the epithelial marker E-cadherin and a significant increase in the extracellular matrix (ECM) marker α-smooth muscle actin in a dose and time-dependent manner. Moreover, PQ-treated RLE-6NT cells had an EMT-like phenotype with elevated expression of MMP-2, MMP-9, and COL I and COL III and enhanced migration ability. Signal pathway analysis revealed that PQ-induced EMT led to ERK-1 and Smad2 phosphorylation through activation of the MAPK pathway. The results of the current study indicate that PQ-induced pulmonary fibrosis occurs via EMT, which is mediated by the MAPK pathway. This implies that the MAPK pathway is a promising therapeutic target in alveolar epithelial cells. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1407-1414, 2016.
上皮-间充质转化（EMT）被认为参与了百草枯（PQ）诱导的肺纤维化过程；然而，这一过程的分子机制尚未明确。本研究探讨了 EMT 在 PQ 中毒后的潜在作用。通过 Western blot 分析评估了 EMT 标志物（如 E-钙黏蛋白和α-平滑肌肌动蛋白（α-SMA））在暴露于不同浓度 PQ 后的多个时间点的表达。在 PQ 处理后，通过显微镜观察到 EMT 的诱导。还通过 RT-PCR 分析测量相关纤维化基因（包括基质金属蛋白酶 2（MMP-2）、基质金属蛋白酶 9（MMP-9）、I 型胶原蛋白（COL I）和 III 型胶原蛋白（COL III））的 mRNA 水平来评估它们。使用选择性 MAPK 药理学抑制剂分析信号通路。通过划痕伤口和 Transwell 测定评估细胞迁移能力。数据显示，PQ 诱导上皮 RLE-6NT 细胞向间充质细胞特征发展，表现为上皮标志物 E-钙黏蛋白显著减少，细胞外基质（ECM）标志物α-SMA 显著增加，呈剂量和时间依赖性。此外，PQ 处理的 RLE-6NT 细胞具有 EMT 样表型，MMP-2、MMP-9 和 COL I 和 COL III 的表达上调，迁移能力增强。信号通路分析表明，PQ 诱导的 EMT 通过激活 MAPK 通路导致 ERK-1 和 Smad2 磷酸化。本研究结果表明，PQ 诱导的肺纤维化通过 EMT 发生，该 EMT 由 MAPK 通路介导。这意味着 MAPK 通路是肺泡上皮细胞有前途的治疗靶点。© 2015 威利父子公司，环境毒理学 31: 1407-1414，2016。
