TGF-β2 stimulates Tenon's capsule fibroblast proliferation in patients with glaucoma via suppression of miR-29b expression regulated by Nrf2.

PURPOSE: To investigate the role of transforming growth factor-β2 (TGF-β2) in Tenon's capsule fibroblasts proliferation from glaucoma patients and the effect of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) and miR-29b mRNA in this process.

METHODS: Tenon's capsule fibroblasts obtained from patients who had undergone selective glaucoma surgery (GTFs) were cultured and stimulated with 5 ng/mL TGF-β2 for 1, 3, 5, and 7 days. MTS assay was performed to detect the cell viability. Expression of Nrf2 and miR-29b was analyzed with western blot, RT-PCR and Chromatin immunoprecipitation assay (ChIP) in human fibroblast SX1412-B exposed to TGF-β2.

RESULTS: MTS assay showed that TGF-β2 was more stimulatory on GTFs proliferation than controls. At the same time, TGF-β2 exerted an intenser effect of decreasing the Nrf2 protein and miR-29b mRNA levels in GTFs, and the level of miR-29b was effectively regulated by Ad-Nrf2. In addition, ChIP assay suggested that TGF-β2 down-regulated miR-29b expression through repressing the binding of Nrf2 to the promoter of miR-29b. Finally, we found that overexpression Nrf2 in GTFs reduced the proliferation effect on GTFs induced by TGF-β2, while miR-29b inhibitor reversed this effect.

CONCLUSION: This study suggests that TGF-β2 has a time-effect relationship with Tenon's capsule fibroblasts proliferation from glaucoma patients, and it stimulates Tenon's capsule fibroblast proliferation via suppression of miR-29b expression regulated by Nrf2.