Inhibitory effect of Anwulignan on the IL-36R/TLR9 signaling pathway: potential therapeutic role in hepatic fibrosis

Background Liver fibrosis is a critical pathological stage in the progression of chronic liver diseases, yet safe and effective antifibrotic agents remain lacking. Anwulignan (Anwu), a lignan component derived from the traditional hepatoprotective herb Schisandra chinensis (Turcz.) Baill., possesses hepatoprotective properties; however, its antifibrotic potential and underlying mechanism remain undefined. Purpose To evaluate the antifibrotic efficacy of Anwu and elucidate the role of the interleukin-36 receptor (IL-36R)/Toll-like receptor 9 (TLR9) signaling pathway in its mechanism of action. Methods Thioacetamide-induced liver fibrosis in mice and TGF-β-activated LX-2 cells were employed to evaluate Anwu’s antifibrotic activity. Transcriptomic profiling and pathway enrichment were performed, and functional validation was achieved through IL-36R and TLR9 knockdown in vivo and in vitro. Results Anwu markedly alleviated hepatic injury and collagen deposition, reduced serum aminotransferase levels, and restored extracellular matrix homeostasis by suppressing α-smooth muscle actin and type I collagen while upregulating matrix metalloproteinase-9. Transcriptomic analysis revealed that IL-36R and TLR9 were markedly upregulated during liver fibrosis but were significantly downregulated following Anwu treatment, suggesting that the IL-36R/TLR9 signaling axis may serve as a key target for its antifibrotic action. Genetic knockdown further confirmed this pathway dependence, as silencing either IL-36R or TLR9 mimicked Anwu’s therapeutic effects and occluded any additional benefit from Anwu treatment. Consistent findings were validated in human liver transcriptomic data, highlighting the clinical relevance of this pathway. Conclusion Anwu exerts antifibrotic effects via a previously unrecognized IL-36R/TLR9-mediated mechanism that links inflammatory resolution to matrix remodeling, underscoring its distinctive pharmacology and translational promise.