Bone morphogenetic protein-6 suppresses TGF-β 2 -induced epithelial-mesenchymal transition in retinal pigment epithelium.

AIM: 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).

METHODS: 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.

RESULTS: 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).

CONCLUSION: 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.