Proteomic analysis of the regulation of quercetin on TNF-α/IFN-γ- induced hyperactivation of keratinocytes

Context Quercetin is a naturally occurring flavonoid that has been shown to have anti-allergic properties, which has been traditionally used for atopic dermatitis (AD) therapy in China. However, the molecular mechanisms underlying the anti-AD properties of quercetin is unclear. Objective To explore the molecular mechanism of quercetin on AD by proteomics. Materials and methods CCK8 was used to detect the cytotoxicity of different concentrations of quercetin on HaCaT cells. The effect of quercetin pretreatment on the gene expression of cytokines and chemokines in TNF-α/IFN-γ -induced HaCaT cells was detected by quantitative real-time PCR (qPCR). Candidate proteins were identified by proteomics and validated by western blot (WB). Results Quercetin showed no cytotoxicity at the highest concentration (80 μM) and dose-dependently inhibited the mRNA overexpression of cytokines/chemokines (IL-1β, TSLP, MDC, CXCL1, CXCL10, CXCL11) induced by TNF-α/IFN-γ. Proteomics analysis revealed that the TNF-α/IFN-γ group identified a total of 1086 differentially expressed proteins (DEPs), while the quercetin group identified 119 DEPs. Among them, 49 of the DEPs could be reversed by quercetin treatment. Functional annotation analysis showed that quercetin's role involved regulation of NF-κB signal transduction and cytokine mediated signaling pathways. The pathway enrichment analysis showed that the Toll-like signaling pathway was significantly enriched after quercetin treatment. STAT1 plays an important role in cytokine-mediated signaling pathways and was significantly downregulated by quercetin. Discussion and conclusions Quercetin effectively inhibited the excessive activation of keratinocytes caused by TNF-α/IFN-γ. The mechanism involves multiple target actions, which can reverse the disease-related proteomic dysregulation and regulate key immune-inflammatory pathways, highlighting its potential role in the treatment of AD.