Epitranscriptomic Analysis of the Ventral Hippocampus in a Mouse Model of Post-Traumatic Stress Disorder Following Deep Brain Stimulation Treatment of the Basolateral Amygdala.

BACKGROUND

Basolateral amygdala (BLA) deep brain stimulation (DBS) has been shown to alleviate the symptoms of post-traumatic stress disorder (PTSD), but the specific mechanisms remain incompletely understood. The hippocampus, a brain region closely connected to the amygdala, plays a key role in the pathological processes of PTSD. The N6-methyladenosine (mA) methylation of RNAs in the hippocampus is known to play a significant role in regulating the brain's response to stress and emotional disorders.

METHODS

This study aimed to comprehensively analyze the roles of transcriptome-wide mA modifications of the hippocampus in the BLA DBS treatment of a PTSD mouse model using mA sequencing.

RESULTS

Significant alterations in functional connectivity between the ventral hippocampus (vHPC) and BLA were observed in foot shock (FS) mice through functional magnetic resonance imaging (fMRI) analysis. Furthermore, we observed that the expression of the key mA methyltransferase enzyme, METTL3, in the FS and BLA DBS groups was higher than that in the control group. At the same time, both FS and BLA DBS induced the widespread mA methylation of RNAs in the vHPC. Gene ontology (GO) enrichment analysis revealed that FS altered methylation in metabolic, developmental, and cytoskeletal pathways, while BLA DBS targeted metabolic, cell cycle, and neuroplasticity-related genes. Additionally, BLA DBS reversed the aberrant methylation of genes associated with multiple functional pathways induced by FS, including those related to cholinergic transmission, sodium and calcium ion homeostasis, and stress hormone responsiveness. We identified a set of RNAs with methylation changes that were reversed by BLA DBS in the FS vs. Ctrl (control) comparison, including those associated with cholinergic transmission, sodium and calcium ion balance, and stress hormone response. Additionally, we detected several specific BLA DBS-related genes through MeRIP-qPCR, indicating that DBS influences crucial genes linked to calcium signaling and synaptic plasticity.

CONCLUSIONS

We draw two conclusions from these findings: BLA DBS may alleviate PTSD-like symptoms by reversing FS-induced methylation changes and by altering the methylation levels of crucial genes. These findings indicate that epigenetic mA modifications in the vHPC may play an important role in the amelioration of PTSD using BLA DBS.