Nahomi Rooban B, Nagaraj Ram H
Department of Ophthalmology, University of Colorado, Aurora, Colorado.
Department of Pharmaceutical Science, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, Colorado.
J Cell Biochem. 2018 Aug;119(8):6814-6827. doi: 10.1002/jcb.26877. Epub 2018 Apr 25.
Human lens epithelial cells (HLE) undergo mesenchymal transition and become fibrotic during posterior capsule opacification (PCO), which is a frequent complication after cataract surgery. TGF-β2 has been implicated in this fibrosis. Previous studies have focused on the role of hypoxia-inducible factor-1α (HIF-1α) in fibrotic diseases, but the role of HIF-1α in the TGF-β2-mediated fibrosis in HLE is not known. TGF-β2 treatment (10 ng/mL, 48 h) increased the HIF-1α levels along with the EMT markers in cultured human lens epithelial cells (FHL124 cells). The increase in HIF-1α corresponded to an increase in VEGF-A in the culture medium. However, exogenous addition of VEGF-A (up to 10 ng/mL) did not alter the EMT marker levels in HLE. Addition of a prolyl hydroxylase inhibitor, dimethyloxalylglycine (DMOG, up to 10 µM), enhanced the levels of HIF-1α, and secreted VEGF-A but did not alter the EMT marker levels. However, treatment of cells with a HIF-1α translational inhibitor, KC7F2, significantly reduced the TGF-β2-mediated EMT response. This was accompanied by a reduction in the ERK phosphorylation and nuclear translocation of Snail and Slug. Together, these data suggest that HIF-1α is important for the TGF-β2-mediated EMT of human lens epithelial cells.
人晶状体上皮细胞（HLE）在晶状体后囊膜混浊（PCO）过程中发生间充质转化并纤维化，PCO是白内障手术后常见的并发症。转化生长因子-β2（TGF-β2）与这种纤维化有关。以往的研究主要关注缺氧诱导因子-1α（HIF-1α）在纤维化疾病中的作用，但HIF-1α在TGF-β2介导的HLE纤维化中的作用尚不清楚。TGF-β2处理（10 ng/mL，48小时）可增加培养的人晶状体上皮细胞（FHL124细胞）中HIF-1α水平以及上皮-间质转化（EMT）标志物水平。HIF-1α的增加与培养基中血管内皮生长因子-A（VEGF-A）的增加相对应。然而，外源性添加VEGF-A（高达10 ng/mL）并未改变HLE中的EMT标志物水平。添加脯氨酰羟化酶抑制剂二甲基草酰甘氨酸（DMOG，高达10 μM）可提高HIF-1α水平并分泌VEGF-A，但未改变EMT标志物水平。然而，用HIF-1α翻译抑制剂KC7F2处理细胞可显著降低TGF-β2介导的EMT反应。这伴随着细胞外信号调节激酶（ERK）磷酸化以及Snail和Slug核转位的减少。总之，这些数据表明HIF-1α对TGF-β2介导的人晶状体上皮细胞EMT很重要。
