MicroRNA-181a-5p Down-Regulation Presents Neuroprotective Effect in 1-Methyl-4-Phenylpyridinium-Induced Parkinson’s Disease: An In Vitro Study

Abstract

Background: Parkinson’s disease (PD) is a long-term degenerative disease that mainly affects the central nervous system of the motor system. MicroRNA-181a-5p (miR-181a-5p) is well studied a variety of malignancies. But, till now, there is no report of the role of miR-181a-5p in PD. Methods: miR-181a-5p level was detected using quantitative reverse transcription polymerase chain reaction (qRT-PCR), and western blotting analysis/qRT-PCR was used to measure the level of Sirtuin 1 (SIRT1). We evaluated cell viability and apoptosis using 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and flow cytometry (FCM), and used enzyme linked immunosorbent assay (ELISA) assay to examine the releases of inflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α. Commercially available kits was applied to assess the lactate dehydrogenase (LDH) activity. Western blotting analyse was used to detect nuclear factor-κB p65 (NF-κB p65) and phosphorylated (p)-p65 protein expression. TargetScan and Dual luciferase reporter assay were carried out to determine the interaction between miR-181a-5p and SIRT1. Results: Results showed that miR-181a-5p was up-regulated and SIRT1 was down-regulated in MMP+-treated C6 cells. miR-181a-5p knockdown attenuated the neurotoxicity induced by MMP+-treatment in C6 cells, evidenced by the enhancement of C6 cell viability, and the suppression of C6 cell apoptosis, LDH activity and inflammation. SIRT1 was found as a direct target of miR-181a-5p, and all these effects of miR-181a-5p inhibition on MMP+-treated C6 cells were reversed by SIRT1 knockdown. Conclusion: Our data suggested that miR-181a-5p down-regulation presents neuroprotective effect in MMP+-induced PD in vitro model by targeting SIRT1.