The pathological development of lens epithelial cells (LECs) leads to posterior capsular opacification (PCO). This studywas undertaken to investigate the effects of microRNA-486-5p (miR-486-5p) on TGF-b2-induced proliferation, invasionand epithelial-mesenchymal transition (EMT) in the lens epithelial cell line SRA01/04, and to explore the underlyingmolecular mechanisms. The expression of miR-486-5p in TGF-b2-induced SRA01/04 cells was down-regulated, and theexpression of Smad2, p-Smad2 and p-Smad3 was up-regulated. A dual-luciferase reporter assay revealed that miR-486-5pdirectly targets the 30-UTR of Smad2. MiR-486-5p mimic transfection markedly down-regulated the expression levels ofSmad2, thus inhibiting the expression of p-Smad2 and p-Smad3. MiR-486-5p overexpression in SRA01/04 cells markedlysuppressed TGF-b2-induced proliferation and invasion, inhibited protein expression of CDK2 and CDK4, down-regulatedfibronectin, a-SMA and vimentin and up-regulated E-cadherin; these effects were partly reversed by Smad2 overexpression.In short, these data show that miR-486-5p overexpression can inhibit TGF-b2-induced proliferation, invasion andEMT in SRA01/04 cells by repressing Smad2/Smad3 signalling, implying that miR-486-5p may be an effective target tointerfere in the progression of PCO.