miR-214-3p Targets ß-Catenin to Regulate Depressive-like Behaviors Induced by Chronic Social Defeat Stress in Mice.

ß-Catenin has been implicated in major depressive disorder (MDD), which is associated with synaptic plasticity and dendritic arborization. MicroRNAs (miRNA) are small noncoding RNAs containing about 22 nucleotides and involved in a variety of physiological and pathophysiological process, but their roles in MDD remain largely unknown. Here, we investigated the expression and function of miRNAs in the mouse model of chronic social defeat stress (CSDS). The regulation of ß-catenin by selected miRNA was validated by silico prediction, target gene luciferase reporter assay, and transfection experiment in neurons. We demonstrated that the levels of miR-214-3p, which targets ß-catenin transcripts were significantly increased in the medial prefrontal cortex (mPFC) of CSDS mice. Antagomir-214-3p, a neutralizing inhibitor of miR-214-3p, increased the levels of ß-catenin and reversed the depressive-like behavior in CSDS mice. Meanwhile, antagomir-214-3p increased the amplitude of miniature excitatory postsynaptic current (mEPSC) and the number of dendritic spines in mPFC of CSDS mice, which may be related to the elevated expression of cldn1. Furthermore, intranasal administered antagomir-214-3p also significantly increased the level of ß-catenin and reversed the depressive-like behaviors in CSDS mice. These results may represent a new therapeutic target for MDD.

Rapid Antidepressant Effect of Hydrogen Sulfide: Evidence for Activation of mTORC1-TrkB-AMPA Receptor Pathways.

AIMS: We asked whether hydrogen sulfide (H2S), as the third gaseous mediator, provided fast antidepressant effect on major depressive disorders and underlying mechanisms. RESULTS: The decreased level of H2S was detected in the hippocampus of chronic unpredictable mild stress (CUMS)-treated rats. Acute administration of H2S either by H2S inhalation or by the donor NaHS produced a rapid antidepressant-like behavioral effect. Further investigation demonstrated that this effect of H2S was mediated by reversing the CUMS-induced decrease in dendritic spine density and required the activation of mammalian target of rapamycin (mTOR)C1 and neurotrophic TrkB receptors, which proceeded to increase synaptic protein expression, including postsynaptic density protein 95, synaptophysin, and α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid receptor GluR1/2 subunit. INNOVATION: This study provides the first direct evidence for detecting the decreased H2S in hippocampus of CUMS rats and the biological significance of H2S in treating major depression. CONCLUSION: Our data demonstrate that H2S activates mTORC1 signaling cascades and thereby produces fast-onset antidepressant effect. The study provides a profound insight into H2S or its donors as potent preventive and therapeutic agents for intervention of depression. Antioxid. Redox Signal. 27, 472-488.