Gastrodin Protects Neuronal Cells Against Oxidative Stress Through miRNA-125b-5p/Mamdc2 Axis.

Deregulated reactive oxygen species (ROS) levels trigger oxidative stress (OS) injury that is closely associated with the pathophysiology of various neurological disorders. Therefore, therapeutic efforts at oxidative events in the pathway of neuronal degeneration would be promisingly helpful for intervention and treatment of related diseases. Here, we report that gastrodin, the main bioactive constituent of Rhizoma Gastrodiae, protects the mouse hippocampal HT22 cells from OS caused by hydrogen peroxide (HO), including the increased cell viability, elevated Glutathione (GSH) levels, decreased Malondialdehyde (MDA) activity, and down-regulated ROS levels with restored cell morphology. Through RNA-sequencing (RNA-Seq) and multiple experiments, we screened the gene Mamdc2 that could be a potential regulating target of gastrodin. Mechanistically, gastrodin exerts its protective effects on neuronal cells from oxidative injury by suppressing miRNA-125b-5p, which increases its target Mamdc2 expression. Overexpression of miR-125b-5p mimics significantly attenuates the gastrodin-triggered protective effects against HO in HT22 cells, including the decreased cell viability, down-regulated GSH activity, increased MDA activity, and up-regulated ROS production, compared to the gastrodin-administration with control miRNA group. However, these results could be effectively restored by the ectopic expression of Mamdc2, leading to the opposite outcomes to those of miR-125b-5p mimics-overexpression. Thus, the current study provides evidence that gastrodin has the potential for intervention and therapy of OS injury-associated neurological diseases in future.