Xu Li, Xiang Xudong, Ji Xiaoying, Wang Wenjing, Luo Min, Luo Shuangling, Li Keng, Gong Subo, Liu Shaokun, Ma Libing, Chen Ping, Li Jinxiu
1Department of Respiratory Medicine, The Second Xiangya Hospital, Central South University, Changsha City, Hunan Province, China.
Exp Lung Res. 2014 Jun;40(5):211-21. doi: 10.3109/01902148.2013.879966. Epub 2014 May 2.
Chronic persistent asthma is characterized by airway remodeling, in which epithelial-mesenchymal transition (EMT) may play a significant role. Dehydroepiandrosterone (DHEA), a steroid hormone and testosterone analog, is considered as an important immunomodulating hormone. However, its role in EMT remains unclear. We sought to investigate whether transforming growth factor-β1 (TGF-β1) stimulates human bronchial epithelial cells (16HBE-14o) to undergo EMT, and whether this transition can be abrogated by DHEA.
The 16HBE-14o cells were stimulated with 5 ng/ml TGF-β1 for 3 days to induce EMT, with or without DHEA pretreatment, and assayed for epithelial or mesenchymal markers using Western Blot. The involvement of phosphoinositide 3-kinase (PI3K) -mediated signaling pathway was also evaluated, the epithelial cells were also incubated with pharmacological approaches (agonists and antagonists of Akt, LY294002 or IGF-1) or flutamide, the antagonist of androgen receptor. Results were analyzed using nonparametric statistical tests.
Our data demonstrate that treatment of 16HBE-14o cells with TGF-β1 for 3 days induced EMT as reflected by conversion to the spindle-like morphology, loss of E-cadherin, and acquisition of a-smooth muscle actin (a-SMA). Pretreatment of 16HBE-14o cells with DHEA preserved the epithelial-like morphology, restored the expression of E-cadherin, and abolished the activation of a-SMA, and this effect is a PI3K-dependent mechanism.
Our results indicate that TGF-β1 induces EMT in a PI3K-dependent manner in 16HBE-14o cells. DHEA inhibits the bronchial epithelial to mesenchymal transition via the inhibition of PI3K/Akt-dependent signal pathway stimulated by TGF-β1. Therefore, DHEA may be a useful therapy for asthma.
慢性持续性哮喘的特征是气道重塑，其中上皮-间质转化（EMT）可能起重要作用。脱氢表雄酮（DHEA）是一种类固醇激素和睾酮类似物，被认为是一种重要的免疫调节激素。然而，其在EMT中的作用仍不清楚。我们试图研究转化生长因子-β1（TGF-β1）是否刺激人支气管上皮细胞（16HBE-14o）发生EMT，以及这种转化是否能被DHEA消除。
用5 ng/ml TGF-β1刺激16HBE-14o细胞3天以诱导EMT，有无DHEA预处理，并用蛋白质印迹法检测上皮或间质标志物。还评估了磷酸肌醇3-激酶（PI3K）介导的信号通路的参与情况，上皮细胞还用药理学方法（Akt、LY294002或IGF-1的激动剂和拮抗剂）或氟他胺（雄激素受体拮抗剂）孵育。结果采用非参数统计检验进行分析。
我们的数据表明，用TGF-β1处理16HBE-14o细胞3天诱导了EMT，表现为转化为纺锤样形态、E-钙黏蛋白丢失和α-平滑肌肌动蛋白（α-SMA）的获得。用DHEA预处理16HBE-14o细胞可保留上皮样形态，恢复E-钙黏蛋白的表达，并消除α-SMA的激活，且这种作用是一种PI3K依赖性机制。
我们的结果表明，TGF-β1在16HBE-14o细胞中以PI3K依赖性方式诱导EMT。DHEA通过抑制TGF-β1刺激的PI3K/Akt依赖性信号通路来抑制支气管上皮向间质转化。因此，DHEA可能是一种治疗哮喘的有效方法。
