TGF-β2 介导的人视网膜色素上皮细胞上皮-间充质转化中 Na,K-ATPaseβ1 亚基的调节。
Regulation of Na,K-ATPase β1-subunit in TGF-β2-mediated epithelial-to-mesenchymal transition in human retinal pigmented epithelial cells.
机构信息
Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Rockland Center I, 1701 Rockland Road, Wilmington, DE 19803, USA.
出版信息
Exp Eye Res. 2013 Oct;115:113-22. doi: 10.1016/j.exer.2013.06.007. Epub 2013 Jun 28.
Proliferative vitreo retinopathy (PVR) is associated with extracellular matrix membrane (ECM) formation on the neural retina and disruption of the multilayered retinal architecture leading to distorted vision and blindness. During disease progression in PVR, retinal pigmented epithelial cells (RPE) lose cell-cell adhesion, undergo epithelial-to-mesenchymal transition (EMT), and deposit ECM leading to tissue fibrosis. The EMT process is mediated via exposure to vitreous cytokines and growth factors such as TGF-β2. Previous studies have shown that Na,K-ATPase is required for maintaining a normal polarized epithelial phenotype and that decreased Na,K-ATPase function and subunit levels are associated with TGF-β1-mediated EMT in kidney cells. In contrast to the basolateral localization of Na,K-ATPase in most epithelia, including kidney, Na,K-ATPase is found on the apical membrane in RPE cells. We now show that EMT is also associated with altered Na,K-ATPase expression in RPE cells. TGF-β2 treatment of ARPE-19 cells resulted in a time-dependent decrease in Na,K-ATPase β1 mRNA and protein levels while Na,K-ATPase α1 levels, Na,K-ATPase activity, and intracellular sodium levels remained largely unchanged. In TGF-β2-treated cells reduced Na,K-ATPase β1 mRNA inversely correlated with HIF-1α levels and analysis of the Na,K-ATPase β1 promoter revealed a putative hypoxia response element (HRE). HIF-1α bound to the Na,K-ATPase β1 promoter and inhibiting the activity of HIF-1α blocked the TGF-β2 mediated Na,K-ATPase β1 decrease suggesting that HIF-1α plays a potential role in Na,K-ATPase β1 regulation during EMT in RPE cells. Furthermore, knockdown of Na,K-ATPase β1 in ARPE-19 cells was associated with a change in cell morphology from epithelial to mesenchymal and induction of EMT markers such as α-smooth muscle actin and fibronectin, suggesting that loss of Na,K-ATPase β1 is a potential contributor to TGF-β2-mediated EMT in RPE cells.
增殖性玻璃体视网膜病变（PVR）与神经视网膜上细胞外基质膜（ECM）的形成以及多层视网膜结构的破坏有关，导致视力扭曲和失明。在 PVR 疾病进展过程中，视网膜色素上皮细胞（RPE）丧失细胞间粘附性，经历上皮间质转化（EMT），并沉积 ECM，导致组织纤维化。EMT 过程通过暴露于玻璃体液细胞因子和生长因子（如 TGF-β2）来介导。以前的研究表明，Na，K-ATPase 对于维持正常极化上皮表型是必需的，并且 Na，K-ATPase 功能和亚基水平的降低与 TGF-β1 介导的肾细胞 EMT 有关。与大多数上皮细胞（包括肾细胞）中的 Na，K-ATPase 基底外侧定位相反，Na，K-ATPase 存在于 RPE 细胞的顶膜上。我们现在表明，EMT 也与 RPE 细胞中 Na，K-ATPase 表达的改变有关。TGF-β2 处理 ARPE-19 细胞导致 Na，K-ATPaseβ1mRNA 和蛋白水平随时间的推移而降低，而 Na，K-ATPaseα1 水平、Na，K-ATPase 活性和细胞内钠离子水平基本保持不变。在 TGF-β2 处理的细胞中，Na，K-ATPaseβ1mRNA 的减少与 HIF-1α 水平呈负相关，并且对 Na，K-ATPaseβ1 启动子的分析显示出一个假定的缺氧反应元件（HRE）。HIF-1α 结合到 Na，K-ATPaseβ1 启动子上，并且抑制 HIF-1α 的活性阻止了 TGF-β2 介导的 Na，K-ATPaseβ1 减少，这表明 HIF-1α 在 EMT 期间在 RPE 细胞中 Na，K-ATPaseβ1 的调节中发挥潜在作用。此外，ARPE-19 细胞中 Na，K-ATPaseβ1 的敲低与细胞形态从上皮向间充质的变化以及 EMT 标志物如α-平滑肌肌动蛋白和纤维连接蛋白的诱导有关，表明 Na，K-ATPaseβ1 的丧失可能是 TGF-β2 介导的 RPE 细胞 EMT 的潜在贡献者。
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