Asperuloside suppresses the progression of depression through O-GlcNAcylation of IκBα and regulating NFκB signaling

Abstract

Depression is a pervasive mental disorder that poses a significant threat to human health globally. Asperuloside (ASP), an iridoid glycoside extracted from Herba Paederiae, exhibits a range of pharmacological activities, including anti-tumor and anti-inflammatory effects. This study aims to explore the function and molecular mechanisms of ASP in alleviating depression. Chronic unpredictable mild stress (CUMS) was employed to establish a rat model of depression. Behavioral tests were conducted to evaluate the antidepressant effects of ASP. Apoptosis in hippocampal tissues was assessed using TUNEL assay. Primary hippocampal neuron apoptosis was assessed using Annexin V/PI staining and flow cytometry, while cell death was detected via PI staining. The expression levels of target mRNAs and proteins were analyzed by quantitative PCR (qPCR) and western blotting, respectively. Additionally, the levels of O-GlcNAcylation and ubiquitination were determined by western blot analysis following immunoprecipitation. Molecular docking was performed to elucidate the interaction mode between ASP and its target protein, O-linked β-N-acetylglucosamine transferase (OGT). Our findings revealed that ASP treatment significantly ameliorated depression-like behaviors and cognitive dysfunction, as well as inhibited hippocampus apoptosis in CUMS-induced rats, Moreover, ASP inhibited LPS-induced neuronal cell apoptosis and suppressed the activation of the NF-κB signaling pathway. Mechanistically, we demonstrated that ASP promoted O-GlcNAcylation of IκBα, and suppressed its ubiquitination and phosphorylation, thereby stabilizing IκBα protein. In conclusion, ASP exerts antidepressant effects by enhancing IκBα O-GlcNAcylation, thus inhibiting its ubiquitination and phosphorylation. These findings provide a novel therapeutic target for the treatment of depression.