Knockdown Of Mir-125-3p Protects Against Oxidative Stress In Pc-12 Cells By Targeting Mef2

Aim: Spinal cord injury (SCI) is a devastating and common neurological disorder which causes local oxidative damage. The study aimed to investigate the underlying role of miR-125-3p mediated by expression of myocyte enhancer factor-2 (MEF2) in oxidative stress induced during spinal cord injury. Methods: Rat derived pheochromocytoma of adrenal medulla cells (PC-12) were cultured in plates and H2O2 was used as stimulus. PC-12 cells were transfected with miR-125-3p mimics to facilitate overexpression or suppression (silencing) of miR-125-3p expression, respectively. qRT-PCR was performed for testing the expression levels of miR-125-3p in PC-12 cells. CCK-8 and apoptosis assays were performed to evaluate the cell survival and apoptosis rates of PC-12 cells. ROS and dual luciferase activity assays were also performed. Western blot analysis was also performed to evaluate the levels of expression of different proteins associated with PI3K/AKT and Notch pathways. Results: H2O2 induced oxidative damage in PC-12 cells in a concentration dependent manner. H2O2 induced apoptosis and increased the ROS levels in PC-12 cells. MiR-125-3p was abnormally expressed in PC-12 cells and reduced oxidative damage in PC-12 cells and vice versa. Expression of miR-125-3p is directly regulated by myocyte enhancer factor 2 (MEF2). Knockdown of miR-125-3p activated PI3K/AKT pathway and suppressed Notch pathway by upregulation of MEF2. Conclusion: These findings suggested that knockdown of miR-125-3p protects PC-12 cells against oxidative stress by targeting MEF2. This might in turn provide novel insights regarding the role of circulating miRNAs especially miR-125-3p in pathogenesis of oxidative damage caused during SCI.