Hsa-miR-155 regulates the cell cycle and barrier function of corneal endothelial cells through E2F2

This study was aimed to determine the role of has-miR-155 and E2F2 on corneal endothelial cells. Real-time quantitative PCR and Western blot assays were carried out to determine the levels of has-miR-155 and E2F2, and Flow cytometry assay was conducted to detect cell cycle. In addition, Targetscan7.2 was adopted to analyze the internal connection between hsa-miR-155 and E2F2, and a dual luciferase reporter gene assay to determine predicted site between has-miR-155 and E2F2. Increased hsa-miR-155 resulted in decreased E2F2, while decreased hsa-miR-155 increased the level of E2F2. In addition, both increased hsa-miR-155 and decreased E2F2 led to an increase in S-phase cells and a decrease in G1-phase cells. Also, they induced an increase in the activity of barrier-related proteins MLCK and ZO-1, an up-regulation of Cyclin D1 and Cyclin E1, and a down-regulation of apoptosis proteins (Caspase 3/Bax/Bim/Bid) whereas decreased hsa-miR-155 led to an opposite change in cells, and decreased E2F2 could offset cell changes caused by increased has-miR-155. In conclusion, Has-miR-155 regulates the cell cycle of corneal endothelial cells and improves their barrier function by down regulating E2F2.