Role of reactive oxygen species in epithelial­-mesenchymal transition and apoptosis of human lens epithelial cells

Abstract

AIM: To investigate the role of reactive oxygen species (ROS) in epithelial–mesenchymal transition (EMT) and apoptosis of human lens epithelial cells (HLECs). METHODS: Flow cytometry was used to assess ROS production after transforming growth factor β2 (TGF-β2) induction. Apoptosis of HLECs after H2O2 and TGF-β2 interference with or without ROS scavenger N-acetylcysteine (NAC) were assessed by flow cytometry. The corresponding protein expression levels of the EMT marker α-smooth muscle actin (α-SMA), the extracellular matrix (ECM), marker fibronectin (Fn), and apoptosis-associated proteins were detected by using Western blotting in the presence of an ROS scavenger (NAC). Wound-healing and Transwell assays were used to assess the migration capability of HLECs. RESULTS: TGF-β2 stimulates ROS production within 8h in HLECs. Additionally, TGF-β2 induced HLECs cell apoptosis, EMT/ECM synthesis protein markers expression, and pro-apoptotic proteins production; nonetheless, NAC treatment prevented these responses. Similarly, TGF-β2 promoted HLECs cell migration, whereas NAC inhibited cell migration. We further determined that although ROS initiated apoptosis, it only induced the accumulation of the EMT marker α-SMA protein, but not COL-1 or Fn. CONCLUSION: ROS contribute to TGF-β2-induced EMT/ECM synthesis and cell apoptosis of HLECs; however, ROS alone are not sufficient for EMT/ECM synthesis.

Keywords

• human lens epithelial cells
• epithelial–mesenchymal transition
• transforming growth factor β2
• reactive oxygen species
• apoptosis