Calycosin Interacts with HMGB1 to Reduce Chondrocyte Injury and Prevent Osteoarthritis

Background/Aims: This study aims to elucidate the role and mechanism of secreted autophagy protein HMGB1 in calycosin’s improvement of chondrocyte damage and prevention of osteoarthritis (OA).

Materials and Methods: This study used the STITCH database to detect the interaction between HMGB1 and calycosin; cell viability was evaluated through the cell counting kit-8 (CCK-8) assay. The messenger RNA (mRNA) expression levels of autophagy-related genes, including ATG5, LC3B, and BECN1, were measured using quantitative real-time polymerase chain reaction (PCR); enzyme-linked immunosorbent assays were utilized to determine the concentrations of HMGB1, ATG5, LC3B, BECN1, and the inflammatory cytokines IL-6 and IL-1β in the cell culture supernatants. Protein expression levels of HMGB1, p-p65, and p-IκBα were analyzed using the Western blot technique.

Results: Calycosin is predicted to interact with HMGB1 based on database analysis. As the concentration of IL-1β increased, cell viability progressively decreased. Following IL-1β treatment, the expression of HMGB1 and autophagy- related genes initially increased before gradually decreasing. The expression level of HMGB1 in the IL-1β model group was higher than that in the control group, and a marked upregulation of HMGB1 was observed following rapamycin treatment. The exocytosis of HMGB1 depends on autophagic vesicles. The addition of rapamycin also promoted the extrusion of HMGB1. Different concentrations of calycosin have different toxic effects on SW1353 cells. With the increase of calycosin dose, the exocytosis of HMGB1 and the concentrations of autophagy-related genes ATG5 and BECN1 were downregulated. Compared with the control group, the expression of HMGB1 and p-P65 protein as well as inflammatory factors IL-6 and IL-1β in the model group cells significantly increased, and the expression of p-IkBα significantly decreased. The addition of different doses of calycosin reversed the above changes.

Conclusion: These in vitro findings suggest that calycosin improves cartilage cell damage and may prevent the onset of OA by inhibiting the exocytosis of secretory autophagy protein HMGB1. However, in vivo validation is required before clinical translation.

Cite this article as: Tian L, Cheng M, Zhong Z. Calycosin interacts with HMGB1 to reduce chondrocyte injury and prevent osteoarthritis. ArchRheumatol. 2026;41(4):307-315.