Effects of long noncoding RNA-MIAT on lens epithelial to mesenchymal transition induced by transforming growth factor-β2

Objective

To investigate the roles of long noncoding RNA-myocardial infarction-associated transcript (MIAT) on lens epithelial cells (LECs) fibrosis induced by transforming growth factor-β₂ (TGF-β₂).

Methods

LECs line (SRA01/04) was cultured in conventional DMEM (normal control group) and DMEM containing 10 ng/ml TGF-β₂(TGF-β₂ induced group) for 48 hours.The morphology of the cells was observed under the optical microscope, and the relative expression levels of MIAT, E-cadherin(E-cad), α-smooth muscle action (α-SMA), collagenⅠ(CollⅠ) in protein level and mRNA level were detected by real-time fluorescence quantitative PCR and Western blot, respectively.The cells cultured in DMEM or DMEM containing 10 ng/ml TGF-β₂ were transfected by siNRA empty carrier (siNRA group, siNRA+ TGF-β₂ group) and siRNA-MIAT (siRNA-MIAT group, siNRA-MIAT+ TGF-β₂group) for 48 hours, and the morphology of the cells was observed under the optical microscope, and the relative expression levels of MIAT, E-cadherin(E-cad), α-smooth muscle action (α-SMA), collagenⅠ(CollⅠ) in protein level and mRNA level were detected by real-time fluorescence quantitative PCR and Western blot.

Results

The cells in the normal control group showed the round and polygon in shape, and those in the TGF-β₂induced group showed the spindle-like.Compared with the normal control group, the relative expression levels of MIAT mRNA, α-SMA mRNA and CollⅠmRNA were significantly elevated (2.497±0.644 vs.0.827±0.062; 2.951±0.146 vs.1.085±0.517; 2.115±0.090 vs.1.002±0.088), and the expression of E-Cad mRNA was significantly reduced (0.102±0.027 vs.1.020±0.262) in the TGF-β₂ induced group (P=0.045, 0.004, 0.000, 0.025). The expressions of MIAT, α-SMA, CollⅠ and E-Cad showed a similar trend between two groups.The relative expressions of MIAT protein and mRNA were evidently reduced in the SiRNA-MIAT group compared with the siRNA empty vector group (all at P<0.05). Compared with the siRNA+ TGF-β₂ group, the relative expressions of α-SMA and CollⅠin protein and mRNA levels were significantly reduced, and the expressions of E-cad protwin and mRNA were elevated in the siRNA-MIAT+ TGF-β₂ group (all at P<0.01).

Conclusions

MIAT might participate in TGF-β₂-induced LECs-EMT.The down-regulation of MIAT in the LECs inhibits the fibrosis of LECs.

Myocardial infarction-associated transcript; Long non-coding RNA; Lens epithelial cells; Epithelial to mesenchymal transition; Posterior capsule opacification