Analysis of miRNA expression profiles in amygdala of mice induced by chronic stress in narrow space confinement

Abstract

Objective To analyze the miRNAs expression profile of the amygdala of mice with chronic stress-induced anxiety disorder and explore the key miRNAs and their possible targets. Methods Eight-week -old C57BL/6 male mice with body weight ranging from 18 g to 22 g were randomly divided into anxiety disorder group (n=12) and control group (n=12). The anxiety disorder group have been restrained in narrow space for 10 consecutive days (2 h/d) to create a mouse model of anxiety disorder, while the control group accepted no stress. After the modeling was completed, the anxiety-like behavior of mice was detected by elevated cross maze experiment, open field experiment and light and dark box experiment. Transcriptome sequencing was used to detect the expression of miRNAs in the amygdala of mice between the anxiety disorder group and the control group. The target genes of differentially expressed miRNA were predicted by miRanda. Functional annotation was conducted by Gene Ontology (GO) analysis, and signal pathway analysis by Kyoto Encyclopedia of Genes and Genomes (KEGG) database to explore the important miRNAs in the amygdala that play a role in anxiety disorders. The key miRNAs explored before were quantitatively detected by RT-qPCR. Results The anxiety disorder group showed significant anxiety-like behavior in elevated cross maze, open field and light and dark box experiments. Compared with the control group, the mice in the anxiety disorder group had 35 differentially expressed miRNAs in the amygdala. The results of GO function analysis showed that the predicted target genes were significantly enriched in the functions related to plasticity regulation of synaptic, while the results of KEGG signal pathway analysis showed that the differential miRNA predicted target genes were obviously enriched in signal transduction and cancer-related signaling pathways. The expression of miR-128-2-5p in the anxiety disorder group was significantly decreased (P < 0.05), while the expression of miR-10b-5p, miR-200a-3p, miR-200b-3p and miR-429-3p in the anxiety disorder group were significantly increased (P < 0.05). Among them, the extents of changes of miR-128-2-5p and miR-200a-3p were consistent with the transcriptome sequencing results. Conclusion The key miRNA molecule miR-128-2-5p and its downstream target genes bmpr2, irf6 and rbfox3 may become the potential therapeutic targets for anxiety disorders.

Keywords

• anxiety disorder
• amygdala
• mirna expression profile
• narrow space confinement