State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat‑sen University, Guangzhou, Guangdong 510060, P.R. China.
Mol Med Rep. 2018 Mar;17(3):3607-3614. doi: 10.3892/mmr.2017.8360. Epub 2017 Dec 27.
Transforming growth factor (TGF)-β2-induced epithelial-mesenchymal transition (EMT) in human retinal pigment epithelium (RPE) cells has an important role in the pathophysiology of intraocular fibrotic disorders, which may cause vision impairment and blindness. Autophagy, an intracellular homeostatic pathway, contributes to the physiological and pathological processes of RPE. Furthermore, autophagy has previously been reported to function in the EMT process in numerous tissue and cell types. However, the association between autophagy and the EMT process in RPE cells has not yet been fully determined. The present study demonstrated that TGF‑β2‑treated human RPE cells (ARPE‑19 cell line) exhibited a significantly increased autophagic flux compared with control cells, as determined by western blot analysis of the protein levels of microtubule‑associated protein 1 light chain 3‑II and p62 (also termed sequestosome 1). Furthermore, it was demonstrated that autophagy activation enhanced the TGF‑β2‑induced EMT process in ARPE‑19 cells, and inhibition of autophagy by chloroquine administration attenuated TGF‑β2‑induced EMT, which was determined by analyzing the expression of mesenchymal and epithelial markers by reverse transcription‑quantitative polymerase chain reaction and/or western blotting. A transwell migration and invasion assays was also performed that demonstrated that autophagy activation by rapamycin enhanced TGF‑β2‑stimulated RPE cell migration and invasion, and inhibition of autophagy reduced TGF‑β2‑stimulated RPE cell migration and invasion. These results also demonstrated that autophagy activation enhanced the TGF‑β2‑induced EMT process in ARPE‑19 cells, and inhibition of autophagy attenuated TGF‑β2‑induced EMT. Overall, the results of the present study demonstrated that TGF‑β2‑induced EMT may be regulated by autophagy, thus indicating that autophagy may serve as a potential therapeutic target for the attenuation of EMT in intraocular fibrotic disorders.
转化生长因子-β2（TGF-β2）诱导的人视网膜色素上皮（RPE）细胞上皮-间充质转化（EMT）在眼内纤维性疾病的病理生理学中具有重要作用，可能导致视力损害和失明。自噬是一种细胞内的稳态途径，参与 RPE 的生理和病理过程。此外，先前有报道称自噬在许多组织和细胞类型的 EMT 过程中起作用。然而，自噬与 RPE 细胞 EMT 过程之间的关联尚未完全确定。本研究通过 Western blot 分析微管相关蛋白 1 轻链 3-II 和 p62（也称为自噬体相关蛋白 1）的蛋白水平，证实 TGF-β2 处理的人 RPE 细胞（ARPE-19 细胞系）与对照细胞相比，自噬通量明显增加。此外，还证实自噬激活增强了 ARPE-19 细胞中 TGF-β2 诱导的 EMT 过程，氯喹给药抑制自噬可减弱 TGF-β2 诱导的 EMT，这通过逆转录-定量聚合酶链反应和/或 Western blot 分析分析间充质和上皮标记物的表达来确定。还进行了 Transwell 迁移和侵袭实验，表明雷帕霉素激活自噬增强了 TGF-β2 刺激的 RPE 细胞迁移和侵袭，而自噬抑制减少了 TGF-β2 刺激的 RPE 细胞迁移和侵袭。这些结果还表明，自噬激活增强了 ARPE-19 细胞中 TGF-β2 诱导的 EMT 过程，而自噬抑制减弱了 TGF-β2 诱导的 EMT。综上所述，本研究结果表明，TGF-β2 诱导的 EMT 可能受自噬调节，表明自噬可能成为眼内纤维性疾病中 EMT 减弱的潜在治疗靶点。
