Guangdong Eye Institute, Department of Ophthalmology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan Er Road, Guangzhou, 510080, Guangdong, People's Republic of China.
Graefes Arch Clin Exp Ophthalmol. 2013 Oct;251(10):2363-70. doi: 10.1007/s00417-013-2435-z. Epub 2013 Aug 2.
Post-cataract surgery fibrosis in the lens capsule is caused by epithelial to mesenchymal transition (EMT) of the lens epithelium. Mammalian target of rapamycin (mTOR) has been demonstrated to be a key regulator of EMT. The aim of this study was to investigate the role of mTOR in transforming growth factor β₂ (TGF-β₂)-induced EMT in human lens epithelial cells (HLECs).
Human lens epithelial B-3 (HLEB-3) cells were cultured with 10 ng/ml TGF-β₂ for different periods of time. The expression of E-cadherin, connexin 43, fibronectin and α-smooth muscle actin (α-SMA), and activation of mTOR were determined by Western blots. Cell migration was assessed by wound healing assay. An inhibition test was performed using two kinds of mTOR inhibitors.
E-cadherin and connexin 43 expressions were suppressed, whereas fibronectin and α-SMA expressions were increased in HLEB-3 cells after treatment with TGF-β₂. mTOR was activated during the TGF-β₂-induced EMT in a time-dependent manner. Rapamycin or Ku-0063794 with 100 nM was able to inhibit the phosphorylation of mTOR and impaired EMT induced by TGF-β₂. Cell motility enhanced by TGF-β₂ for 24 h was attenuated by both rapamycin and Ku-0063794.
mTOR is activated during TGF-β₂-induced EMT in HLECs, suggesting that it is involved in the regulation of TGF-β₂-induced EMT and may contribute to the development of posterior capsule opacification.
白内障手术后晶状体囊中的纤维组织增生是由晶状体上皮细胞的上皮-间质转化（EMT）引起的。哺乳动物雷帕霉素靶蛋白（mTOR）已被证明是 EMT 的关键调节因子。本研究旨在探讨 mTOR 在转化生长因子 β₂（TGF-β₂）诱导的人晶状体上皮细胞（HLECs）EMT 中的作用。
用 10ng/ml TGF-β₂培养人晶状体上皮 B-3（HLEB-3）细胞不同时间。通过 Western blot 检测 E-钙黏蛋白、连接蛋白 43、纤连蛋白和α-平滑肌肌动蛋白（α-SMA）的表达以及 mTOR 的激活情况。通过划痕愈合试验评估细胞迁移。使用两种 mTOR 抑制剂进行抑制试验。
TGF-β₂处理后，HLEB-3 细胞中 E-钙黏蛋白和连接蛋白 43 的表达受到抑制，而纤连蛋白和α-SMA 的表达增加。mTOR 在 TGF-β₂诱导的 EMT 过程中呈时间依赖性激活。雷帕霉素或 100nM 的 Ku-0063794 能够抑制 mTOR 的磷酸化，并损害 TGF-β₂诱导的 EMT。TGF-β₂作用 24 小时后增强的细胞迁移被雷帕霉素和 Ku-0063794 减弱。
mTOR 在 HLECs 的 TGF-β₂诱导的 EMT 过程中被激活，提示其参与 TGF-β₂诱导的 EMT 的调节，并可能有助于后囊混浊的发生。
