Background
Retinal neovascularization, which is characterized by the increased proliferation, migration, and tube formation of retinal microvascular endothelial cells (RMECs), contributes to the progression of diabetic retinopathy (DR). MiR-409-5p has been reported to be upregulated in peripheral blood of DR patients and in vascular endothelial growth factor (VEGF)-induced RMECs. However, the role of miR-409-5p in retinal neovascularization of DR remains unelucidated. Method: The expression of miR-409-5p was measured in retinal tissues of streptozocin-induced and db/db diabetic mice, in high glucose-induced mouse RMECs (mRMECs), and in vitreous fluid of proliferative DR patients. Antagomir of miR-409-5p was intravitreally injected into diabetic mice. Proliferation, migration, and tube formation were detected using cell counting kit-8 assay, transwell assay, and microscope observation, respectively. Luciferase reporter assay was used to detect the direct interaction between miR-409-5p and peroxisome proliferator-activated receptor-α (PPARα). Result: MiR-409-5p was upregulated in retinal tissues of diabetic mice, in high glucose-induced mRMECs, and in vitreous fluid of proliferative DR patients. The knockdown of miR-409-5p attenuated retinal neovascularization in vivo. The overexpression of miR-409-5p promotes the proliferation, migration, and tube formation, and increased VEGF expression and secretion, while the knockdown of miR-409-5p suppressed the VEGF-induced retinal neovascularization in vitro. PPARα is a downstream target of miR-409-5p, and PPARα overexpression negated the promotion of miR-409-5p overexpression on the proliferation, migration, and tube formation of mRMECs.
Conclusion
Our findings demonstrated that miR-409-5p acted as a neovasculogenic factor in DR, and anti-miR-409-5p therapy may provide a novel strategy in treating DR.