Involvement of epithelial-mesenchymal transition in methotrexate-induced pulmonary fibrosis
Involvement of epithelial-mesenchymal transition in methotrexate-induced pulmonary fibrosis
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DOI：
10.2131/jts.39.319
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发表时间：
2014-04-01
影响因子：
2
通讯作者：
Yamamoto, Toshinori
中科院分区：
文献类型：
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作者：
Ohbayashi, Masayuki;Kubota, Satoshi;Yamamoto, Toshinori
上皮间质转化（EMT）在肺纤维化的发生发展中起着关键作用。我们以前曾报道，甲氨蝶呤（MTX）诱导的肺泡上皮细胞损伤，随后肺纤维化的结果招募和增殖的肌成纤维细胞。然而，目前尚无关于甲氨蝶呤诱导的肺纤维化是否发生EMT的数据。因此，在本研究中，我们通过免疫荧光分析研究了MTX给药后小鼠肺组织中EMT标志物如E-cadherin、α-SMA和波形蛋白的表达。我们发现，波形蛋白和α-SMA阳性细胞的MTX诱导的肺纤维化增加，另一方面，E-钙粘蛋白减少，表明上皮细胞作为间充质扩张的主要来源。这些结果表明，在原代小鼠肺泡上皮细胞（MAECs）和A549细胞系中，E-cadherin表达下调，α-平滑肌肌动蛋白（α-SMA）表达上调。此外，MTX诱导的A549细胞表现出EMT样表型，伴随着白细胞介素-6（IL-6）和转化生长因子（TGF）-β 1表达的升高，以及迁移的增强。所有这些结果表明，MTX诱导的肺纤维化通过EMT发生。
Epithelial-mesenchymal transition (EMT) plays a pivotal event in the development of pulmonary fibrosis. We have previously reported that methotrexate (MTX)-induced alveolar epithelial cell injury followed by pulmonary fibrosis as a result of the recruitment and proliferation of myofibroblasts. However, there is no data concerning whether EMT occurs in MTX-induced pulmonary fibrosis. In the present study, therefore, we investigated the expression of EMT markers such as E-cadherin, alpha-SMA, and vimentin by immunofluorescence analysis in mouse lung tissues after administration of MTX. We found that vimentin and alpha-SMA-positive cells of the MTX-induced pulmonary fibrosis were increased; on the other hand, E-cadherin was decreased, indicating that epithelial cells act as the main source of mesenchymal expansion. These results exhibited the down-regulation of E-cadherin expression and the up-regulation of alpha-smooth muscle actin (alpha-SMA) in primary mouse alveolar epithelial cells (MAECs) and A549 cell lines. Additionally, MTX-induced A549 cells exhibited an EMT-like phenotype accompanied by the elevation of the expression of interleukin-6 (IL-6) and transforming growth factor (TGF)-beta 1, as well as an enhancement of migration. All of these findings suggest that MTX-induced pulmonary fibrosis occurs via EMT.