Abstract
Spinal cord injury (SCI) is one of the most devastating diseases. MicroRNAs (miRNAs) are recognized as key regulators in SCI; however, the role of miR-223 in SCI remains unclear. Herein, our study aimed to explore the effect of miR-223 on lipopolysaccharide (LPS)-induced injury to PC-12 cells. PC-12 cells were treated with different concentrations of LPS, and then cell viability, apoptosis, apoptosis-related factors and autophagy-related factors were analyzed by CCK-8, flow cytometry and western blot. Subsequently, miR-223 mimic, miR-223 inhibitor, pEX-RPH1, sh-RPH1 and corresponding controls were transfected into PC-12 cells followed by 5 μg/ml of LPS treatment. Cell viability, apoptosis, apoptosis-related and autophagy-related factors were analyzed again. A target gene of miR-223 was validated by dual-luciferase assay. Besides, the main factors expressions of mTOR and NF-κB signal pathways were measured by western blot. LPS reduced cell viability but increased apoptotic cells rate, up-regulated Bax, cleaved-caspase-3, cleaved-caspase-9, LC-II and Beclin-1, and down-regulated Bcl-2 and p62 expressions in a dose-dependent way. Additionally, miR-223 overexpression promoted cell viability but inhibited apoptosis, and autophagy in LPS-stimulated PC-12 cells. RPH1 was a direct target of miR-223, and RPH1 exhibited contrary impacts to miR-223 on LPS-induced cell apoptosis and autophagy. Besides, the promoting effects of miR-223 suppression on cell apoptosis and autophagy were relieved by RPH1 silence. Furthermore, miR-223 blocked LPS-induced mTOR and NF-κB pathways by down-regulation of RPH1. MiR-223 improved cell viability but declined apoptosis and autophagy by targeting RPH1 and blocked mTOR and NF-κB pathways in LPS challenged PC-12 cells.