Bone morphogenetic protein-6 suppresses TGF-β₂-induced epithelial-mesenchymal transition in retinal pigment...

To evaluate the effect of bone morphogenetic protein-6 (BMP-6) on transforming growth factor (TGF)-β₂-induced epithelial-mesenchymal transition (EMT) in retinal pigment epithelium (RPE).

Adult retinal pigment epithelial cell line (ARPE-19) were randomly divided into control, TGF-β₂ (5 µg/L), and BMP-6 small interfering RNA (siRNA) group. The cell morphology was observed by microscopy, and the cell migration ability were detected by Transwell chamber. The EMT-related indexes and BMP-6 protein levels were detected by Western blotting. Furthermore, a BMP-6 overexpression plasmid was constructed and RPE cells were divided into the control group, TGF-β₂+empty plasmid group, BMP-6 overexpression group, and TGF-β₂+BMP-6 overexpression group. The EMT-related indexes and extracellular regulated protein kinases (ERK) protein levels were detected.

Compared with the control group, the migration of RPE cells in the TGF-β₂ group was significantly enhanced. TGF-β₂ increased the protein expression levels of α-smooth muscle actin (α-SMA), fibronectin and vimentin but significantly decreased the protein levels of E-cadherin and BMP-6 (P<0.05) in RPE. Similarly, the migration of RPE cells in the BMP-6 siRNA group was also significantly enhanced. BMP-6 siRNA increased the protein expression levels of α-SMA, fibronectin and vimentin but significantly decreased the protein expression levels of E-cadherin (P<0.05). Overexpression of BMP-6 inhibited the migration of RPE cells induced by TGF-β₂ and prevented TGF-β₂ from affecting EMT-related biomarkers (P<0.05).

BMP-6 prevents the EMT in RPE cells induced by TGF-β₂, which may provide a theoretical basis for the prevention and treatment of proliferative vitreoretinopathy.