Hippocampal miR-124 mediates depression-like behavior via the USP14/REST signaling pathway in CRS- and CUMS-induced mouse models.

BACKGROUND

Stress is a significant trigger of depression, and miR-124 has been implicated in stress-induced depression, while the underlying molecular mechanisms remain unclear.

METHODS

We established mouse depression models using chronic restraint stress (CRS) and chronic unpredictable mild stress (CUMS), and the HT-22 cell models with corticosterone (CORT) and glutamate (Glu). Depression-like behaviors were assessed using the forced swimming test, tail suspension test, and sucrose preference test. Adeno-associated viruses were employed to manipulate miR-124 and ubiquitin-specific protease 14 (USP14) expression. mRNA levels of miR-124, Usp14, and Rest were measured by qRT-PCR, the interaction between miR-124 and Usp14 mRNA was assessed by luciferase reporter assays, protein expression and interaction of USP14 and repressor element 1 silencing transcription factor (REST) were detected by western blotting, ubiquitination assay and co-immunoprecipitation. Immunofluorescence visualized altered REST expression in hippocampal neurons.

RESULTS

CRS and CUMS robustly increased miR-124 levels in the hippocampus, while decreasing the USP14 and REST expression. Similar expression changes were seen in CORT- and Glu-treated HT-22 cells. Mice with miR-124 overexpression but not inhibition in the hippocampus exhibited notable depression-like behavior. Mechanistically, miR-124 directly targeted USP14, reduced USP14 binding to REST, thereby increasing REST ubiquitination and degradation. Inhibition of miR-124 produced antidepressant-like effects and restored the expression and interaction of USP14 and REST in the CRS and CUMS mice. Furthermore, overexpression of USP14 alleviated depression-like behaviors and low REST levels.

CONCLUSION

Hippocampal miR-124 mediates depression-like behavior under chronic stress via regulating the USP14/REST signaling pathway, highlighting its potential as a therapeutic target.