Downregulation of miR-384-5p attenuates rotenone-induced neurotoxicity in dopaminergic SH-SY5Y cells through inhibiting endoplasmic reticulum stress

In this study, we investigated the role of miR-384-5p in an in vitro model of PD using dopaminergic SH-SY5Y cells treated with rotenone. We found that miR-384-5p was persistently induced by rotenone in neurons. Also, the inhibition of miR-384-5p significantly suppressed rotenone-induced neurotoxicity, while overexpression of miR-384-5p aggravated rotenone-induced neurotoxicity. Through bioinformatics and dual-luciferase reporter assay, miR-384-5p was found to directly target the 3'-untranslated region of glucose-regulated protein 78 (GRP78), the master regulator of ER stress sensors. Quantitative polymerase chain reaction and Western blotting analysis showed that miR-384-5p negatively regulated the expression of GRP78. Inhibition of miR-384-5p remarkably suppressed rotenone-evoked ER stress, which was evident by a reduction in the phosphorylation of activating transcription factor 4 (ATF4) and inositol-requiring enzyme 1 (IRE1α). The downstream target genes of ER stress including CCAAT/enhancer-binding protein-homologous protein (CHOP) and X box-binding protein-1 (XBP-1) were also decreased by the miR-384-5p inhibitor. In contrast, overexpression of miR-384-5p enhanced ER stress signaling. In addition, knockdown of GRP78 significantly abrogated the inhibitory effect of miR-384-5p inhibitors on cell apoptosis and ER stress signaling. Moreover, we observed a significant increase of miR-384-5p expression in primary neurons induced by rotenone. Taken together, our results s...
Source: AJP: Cell Physiology - Category: Cytology Authors: Tags: ARTICLES Source Type: research