Sinomenine treats Rheumatoid Arthritis by regulating IL-6 Gene Promoter Methylation

Sinomenine (SIN) is the main active component of the Chinese herbal medicine Sinomenium acutum (Thunb.) Rehder & E.H.Wilson. It exerts therapeutic effects on rheumatoid arthritis (RA), but its underlying mechanism remains incompletely understood.

This study explored the mechanism of SIN's anti-inflammatory and anti-RA effects by modulating the interleukin-6 (IL-6) gene promoter methylation, using integrated network pharmacology and experimental analysis.

Network pharmacology and bioinformatics identified core targets and signaling pathways of SIN against RA. Molecular docking confirmed binding potential of SIN to core targets. Inflammatory models were established in LPS-stimulated RAW264.7 and THP-1 cells; CCK-8 assay, NO/cytokine (TNF-α, IL-6) detection, Western blot (DNMT1, DNMT3b, p-STAT3, p-JAK2), and bisulfite sequencing (IL-6 promoter methylation in THP-1 cells) were performed. A collagen-induced arthritis (CIA) rat model evaluated in vivo efficacy via foot swelling, arthritis index, cytokine levels, and histological analysis.

SIN targets TNF-α, IL-1β, IL-6, STAT3, PTGS2, JAK2 mainly via the JAK-STAT pathway. In vitro, SIN reduced LPS-induced NO/TNF-α/IL-6, upregulated IL-6 promoter methylation (reversed by 5-Aza). In vivo, SIN alleviated CIA rats' paw edema, arthritis index, synovial inflammation, and lowered TNF-α/IL-6.

SIN alleviates inflammation and RA progression by enhancing IL-6 promoter specific site methylation levels, modulating inflammatory responses via epigenetic regulation.