miR-486-5p Restrains Extracellular Matrix Production and Oxidative Damage in Human Trabecular Meshwork Cells by Targeting TGF-β/SMAD2 Pathway

BACKGROUND: Glaucoma is characterized by elevated intraocular pressure caused by aqueous outflow dysfunction. Trabecular meshwork plays a key role in controlling intraocular pressure by modulating aqueous outflow. This study investigated the protective effects of miR-486-5p in H(2)O(2)-stimulated human trabecular meshwork cells (TMCs). METHODS: TMCs were disposed with 300 μM H(2)O(2) to establish oxidative damage models in vitro. miR-486-5p mimics and its controls were transfected into TMCs, and cell apoptosis and extracellular matrix production (ECM) genes were measured by flow cytometry, western blotting, and immunofluorescence staining. Activities of superoxide dismutase (SOD) and malondialdehyde (MDA) were also assayed. Online tools and luciferase reporter assays were used to uncover the relationship between miR-486-5p and the TGF-β/SMAD2 pathway. RESULTS: We found that H(2)O(2)-induced oxidative damage in TMCs and miR-486-5p was downregulated in H(2)O(2)-stimulated TMCs. Overexpression of miR-486-5p mitigated H(2)O(2)-induced oxidative damage by inhibiting apoptosis, reducing cleaved caspase-3/9 expression, reducing MDA levels, and increasing SOD levels as well as downregulating ECM genes. SMAD2 was demonstrated to be targeted by miR-486-5p, and miR-486-5p inhibited TGF-β/SMAD2 signaling in H(2)O(2)-stimulated TMCs. Additionally, SMAD2 was upregulated by H(2)O(2), and SMAD2 upregulation abrogated the protective effects of miR-486-5p against H(2)O(2)-induced injury. CONCLUSION: miR-486-5p restrains H(2)O(2)-induced oxidative damage in TMCs by targeting the TGF-β/SMAD2 pathway.