Mir-7a targets insulin receptor substrate-2 gene and suppresses viability and invasion of cells in diabetic retinopathy mice via PI3K-AKT-VEGF pathway

Abstract

Introduction: Diabetic retinopathy (DR) is one of the major leading causes for vision loss globally. Current study illustrates the role of miR-7a in DR. Material and Methods: Retinal pericytes (RPs) and Endothelial cells (ECs) were isolated from mouse model of DR. qRT-PCR was done for expression of miR-7a and target gene mRNA, Western blot for protein expression. Identification of miR-7a target gene was done by TargetScan and Luciferase assay. Cell viability and invasion was done by MTT and Transwell chamber assay. Results: The expression of miR-7a was down-regulated whereas level of IRS-2 was unregulated in isolated RPs and ECs. Luciferase assay suggested correlation between miR-7a and IRS-2, over-expression of miR-7a using a mimic resulted in suppression in viability and invasion capacity of RPs and ECs and inhibited the protein levels of PI3K/Akt cascade and IRS-2, and however the inhibitor reversed them respectively. Transfection of siRNA targeting IRS-2 caused alteration in miR-7a mediated changes in ECs suggesting that miR-7a may decrease angiogenesis in DR by inhibiting the levels of IRS-2. Conclusion: miR-7a suppresses PI3K/Akt cascade via targeting IRS-2, thus decreasing the viability and invasion capacity of RPs and ECs, suggesting an interesting treatment target for DR.