The current study investigated the physiological mechanisms by which extracellular vesicle (EV)-encapsulated miR-181a–2–3p derived from mesenchymal stem cells (MSCs) might mediate oxidative stress (OS) in Parkinson’s disease (PD). First, 6-hydroxydopamine (6-OHDA)-induced PD cell and mouse models were established, after which miR-181a–2–3p, EGR1, and NOX4 expression patterns were determined in SH-SY5Y cells and substantia nigra (SN) of PD mice. Next, the binding affinity among miR-181a–2–3p, EGR1, and NOX4 was identified using multiple assays. Gain- or loss-of-function experiments were further adopted to detect SH-SY5Y cell proliferation and apoptosis and to measure the levels of SOD, MDA, and ROS. Finally, the effects of miR-181a–2–3p from MSC-derived EVs in PD mouse models were also explored. It was found that miR-181a–2–3p was poorly expressed in 6-OHDA-induced SH-SY5Y cells, whereas miR-181a–2–3p from MSCs could be transferred into SH-SY5Y cells via EVs. In addition, miR-181a–2–3p could target and inhibit EGR1, which promoted the expression of NOX4. The aforementioned miR-181a–2–3p shuttled by MSC-derived EVs facilitated SH-SY5Y proliferation and SOD levels, but suppressed apoptosis and MDA and ROS levels by regulating EGR1 via inhibition of NOX4/p38 MAPK, so as to repress OS of PD. Furthermore, in PD mice, miR-181a–2–3p was carried by EVs from MSCs to alleviate apoptosis of dopamine neurons and OS, accompanied by increased expressions of α-syn and decreased 4-HNE in SN tissues. Collectively, our findings revealed that MSC-derived EV-loaded miR-181a–2–3p downregulated EGR1 to inhibit OS via the NOX4/p38 MAPK axis in PD.
Background. Ferroptosis is a type of iron-dependent programmed cell death. Ferroptosis has been shown to be a significant factor for the pathogenesis of Parkinson’s disease (PD). However, the mechanism involved in ferroptosis has not been fully elucidated in PD. Methods. Repressor element-1 silencing transcription factor (REST) and specificity protein 1 (SP1) expressions were monitored by qRT-PCR. Cell viability, reactive oxygen species (ROS), and mitochondrial injury were validated by CCK-8, flow cytometry, and transmission electron microscope. The levels of neurons-related proteins and ferroptosis-associated proteins were identified by western blot and immunofluorescence assays. The interaction between miR-494-3p and REST or SP1 and ACSL4 was analyzed by luciferase, chromatin immunoprecipitation, or EMSA assay. Results. Erastin could dose-dependently induce neuron injury and ferroptosis of LUHMES cells. miR-494-3p overexpression induced ROS production, mitochondrial damage, ferroptosis, and neuron injury in erastin-induced LUHMES cells. Likewise, miR-494-3p inhibition had the opposite effects. We also showed that REST was a target gene of miR-494-3p and could repress erastin-induced ferroptosis, neuron injury, ROS, and mitochondrial injury via SP1 in LUHMES cells. Moreover, we demonstrated that SP1 could interact with ACSL4. We also confirmed that miR-494-3p could aggravate the pathological changes of substantia nigra and corpus striatum in the MPTP-induced PD mouse model. Conclusion. miR-494-3p significantly promotes ferroptosis by regulating the REST/SP1/ACSL4 axis in PD. Thus, our results open potential therapeutic targets for PD.
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