microRNA-182 Negatively Influences the Neuroprotective Effect of Apelin Against Neuronal Injury in Epilepsy

PURPOSE: To explore the neuroprotective effects and mechanisms of Apelin (APLN), and to study the regulation of APLN expression by microRNA (miRNA) in epilepsy. MATERIALS AND METHODS: In vitro and in vivo epileptic models were established with hippocampal neurons and Wistar rats. Apoptosis of neurons was identified by flow cytometry. Western blotting was used to detect the expression of proteins, and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) was used to analyze the expression of miRNA and messenger RNA (mRNA). Bioinformatics software was used to predict target genes of miRNA, which were confirmed by dual-luciferase reporter gene system and functional experiments. RESULTS: Our study demonstrated protective effects of APLN against neuronal death in epilepsy both in vitro and in vivo. The underlying mechanisms involved are inhibiting the expression of metabotropic glutamate receptor 1 (mGluR1), Bax, and caspase-3; promoting the expression of Bcl-2; and increasing phosphorylated-AKT (p-AKT) levels in neurons. For the first time, we found that miR-182 could negatively regulate both transcriptional and translational levels of APLN, and that the up-regulation of miR-182 inhibited the expression of APLN and Bcl-2, and promoted the expression of Bax and caspase-3. CONCLUSION: APLN could protect the neurons from injury in epilepsy by regulating the expression of apoptosis-associated proteins and mGluR1 and increasing p-AKT levels, which were attenuated by miR-182. Hence, miR-182/APLN may be potential targets for epilepsy control and treatment.