MicroRNA-139-5p acts as a suppressor gene for depression by targeting nuclear receptor subfamily 3, group C, member 1.

MicroRNA-139-5p (miR-139-5p) is one of the most differentially expressed miRNAs in the brain between healthy people and depressed patients. However, its function in depression is unclear. Therefore, we investigated the function of miR-139-5p in depression. Here, miR-139-5p expression was found to be upregulated in the model group. MiR-139-5p inhibition could increase sucrose preference and decrease mice immobility time after chronic corticosterone (CORT) injection. Furthermore, compared with the antago-NC group, 3 weeks of antagomiR-139-5p treatment significantly decreased miR-139-5p level in model group hippocampus, increased sucrose preference index, reduced neuron damages, and enhanced the levels of nuclear receptor subfamily 3 group C member 1 (NR3C1), brain-derived neurotrophic factor (BDNF), phosphorylated/total tyrosine kinase receptor B (p-TrkB/TrkB), phosphorylated/total cAMP-response element-binding protein (p-CREB/CREB) and phosphorylated/total extracellular regulated protein kinases (p-ERK/ERK). Moreover, as a potential target for miR-139-5p, NR3C1 level was reduced by miR-139-5p mimic. Altogether, by activating the BDNF-TrkB signaling pathway, miR-139-5p inhibition plays an antidepressant-like role and might serve as an effective depression target (Fig. graphical abstract).