Patrícia Gonçalves Tenório Liliane, Xavier Felipe Henrique da Cunha, Silveira Wagner Mônica, Moreira Bagri Kayo, Alves Ferreira Erick Gabriel, Galvani Romulo, Mermelstein Claudia, Bonomo Adriana Cesar, Savino Wilson, Barreto Emiliano
Cell Biology Laboratory, Federal University of Alagoas, Maceió, Brazil.
Laboratory on Thymus Research, Oswaldo Cruz Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil.
Front Pharmacol. 2025 Jan 7;15:1504556. doi: 10.3389/fphar.2024.1504556. eCollection 2024.
The epithelial-mesenchymal transition (EMT) is a biological process in which epithelial cells change into mesenchymal cells with fibroblast-like characteristics. EMT plays a crucial role in the progression of fibrosis. Classical inducers associated with the maintenance of EMT, such as TGF-β1, have become targets of several anti-EMT therapeutic strategies. Natural products from the pentacyclic triterpene class have emerged as promising elements in inhibiting EMT. Uvaol is a pentacyclic triterpene found in olive trees ( L.) known for its anti-inflammatory, antioxidant, and antiproliferative properties. Yet, its effect on the TGF-β1-induced EMT in alveolar epithelial cells is unknown. The present study aimed to investigate the impact of uvaol upon TGF-β1-induced EMT in a cultured A549 human alveolar epithelial cell line, a classic model for studies of EMT. Changes in cell shape were measured using phase-contrast and confocal microscopy, whereas protein expression levels were measured using immunofluorescence, flow cytometry, and Western blotting. We also performed wound scratch experiments to explore its effects on cell migration. Uvaol had no significant cytotoxic effects on A549 cells. By contrast, the changes in the cell morphology consistent with TGF-β1-induced EMT were largely suppressed by treatment with uvaol. In addition, increased contents of mesenchymal markers, namely, vimentin, N-cadherin, and fibronectin in TGF-β1-induced A549 cells, were downregulated by uvaol treatment. Furthermore, the TGF-β1-induced migration of A549 cells was significantly suppressed by uvaol. Mechanistically, uvaol prevented the nuclear translocation of β-catenin and reduced the TGF-β1-induced levels of ZEB1 in A549 cells. These results provide compelling evidence that uvaol inhibits EMT by regulating proteins related to the mesenchymal profile in human alveolar epithelial cells, likely by modulating β-catenin and ZEB1 levels.
上皮-间质转化（EMT）是一个生物学过程，在此过程中上皮细胞转变为具有成纤维细胞样特征的间质细胞。EMT在纤维化进展中起关键作用。与EMT维持相关的经典诱导因子，如转化生长因子-β1（TGF-β1），已成为多种抗EMT治疗策略的靶点。五环三萜类天然产物已成为抑制EMT的有前景的成分。乌索酸是一种在油橄榄（L.）中发现的五环三萜，以其抗炎、抗氧化和抗增殖特性而闻名。然而，其对TGF-β1诱导的肺泡上皮细胞EMT的影响尚不清楚。本研究旨在探讨乌索酸对培养的A549人肺泡上皮细胞系中TGF-β1诱导的EMT的影响，A549细胞系是EMT研究的经典模型。使用相差显微镜和共聚焦显微镜测量细胞形态变化，而使用免疫荧光、流式细胞术和蛋白质印迹法测量蛋白质表达水平。我们还进行了伤口划痕实验以探索其对细胞迁移的影响。乌索酸对A549细胞无明显细胞毒性作用。相比之下，与TGF-β1诱导的EMT一致的细胞形态变化在很大程度上被乌索酸处理所抑制。此外，TGF-β1诱导的A549细胞中间质标志物波形蛋白、N-钙黏蛋白和纤连蛋白含量的增加通过乌索酸处理而下调。此外，乌索酸显著抑制了TGF-β1诱导的A549细胞迁移。机制上，乌索酸阻止了β-连环蛋白的核转位，并降低了A549细胞中TGF-β1诱导的锌指E盒结合蛋白1（ZEB1）水平。这些结果提供了令人信服的证据，表明乌索酸通过调节人肺泡上皮细胞中与间质特征相关的蛋白质来抑制EMT，可能是通过调节β-连环蛋白和ZEB1水平来实现的。
