Effect of Er Miao San on rheumatoid arthritis via the NF-κB signaling pathway: Based on network pharmacology and experimental validation

Abstract Background: This study aims to explore the potential molecular mechanism of Er Miao San (EMS) in rheumatoid arthritis (RA) on the basis of network pharmacology and molecular docking. Methods: The active ingredients and targets of EMS, RA and pathways were obtained through multiple databases. Common targets were analyzed by protein-protein interactions (PPIs) with the STRING database. Gene Ontology (GO) and KEGG enrichment analyses were conducted with the DAVID database to annotate targets of RA and common targets. Hub genes were obtained by the degree algorithm with the cytoHubba plug-in. Based on the determined network pharmacology, experimental validation was performed. Results: In this study, 45 active ingredients, 3162 potential drug targets and 343 pathway targets were uncovered via databases. The top 3 hub targets were obtained by the degree algorithm for 34 common target genes, including NFKBIA (encodes the IκBα protein), RELA (also named p65) and TNF. Molecular docking demonstrated that the core components fumarine, berberine and wogonin (Degree: 19, 16, 16, respectively) bind well to hub targets. In vivo experiments showed that EMS has better protective effects on adjuvant arthritis (AA) rats. In vitro studies demonstrated that EMS could inhibit the proliferation of TNF-ɑ-induced FLSs and attenuate the production of inflammatory cytokines in a dose-dependent manner. Moreover, treatment with EMS significantly decreased the ratio of p-NF-κB p65/NF-κB p65 and p-IκBα/IκBα in FLSs. Furthermore, as shown in the investigations, treatment of FLSs with 10% EMS remarkably suppressed TNF-ɑ-induced nuclear translocation of NF-κB p65 to FLSs. Conclusion: The potential mechanisms and therapeutic effects of EMS on RA may be attributed to the regulation of inflammation, which provides a reference for elucidating the mechanism of action of EMS.