Rhizoma Panacis Majoris ameliorates rheumatoid arthritis by restoring apoptosis and autophagy dysregulation through reducing HMGB1 expression

Abstract

Background

Restoring the autophagy and apoptosis balance in RA synovium may offer a promising RA treatment. Our previous research showed that total saponins from Rhizoma Panacis Majoris (RPMTG) exhibit anti-RA effects by inhibiting autophagy and inducing apoptosis. This study suggests that increased HMGB1 expression and reduced Beclin 1-Bcl-2 complex binding might be key mechanisms behind this dysregulation.

Objective

This study investigated the anti-RA effects of RPMTG on collagen-induced arthritis (CIA) in rats and TNF-α-induced RA fibroblast-like synoviocytes (RA-FLSs), focusing on restoring autophagy and apoptosis balance through regulating HMGB1 expression and the Beclin 1-Bcl-2 complex binding.

Methods

Beclin 1, Bcl-2, and HMGB1 expressions were analyzed using WB, IHC, and RT-qPCR. Beclin 1-Bcl-2 complex binding was examined by Co-IP. Autophagy morphology was observed via TEM, and apoptosis was assessed with Hoechst 33342/PI staining. RPMTG’s therapeutic effect was evaluated through CIA rat symptoms and signs, inflammatory cytokine production via ELISA, and histopathological changes using HE staining. RPMTG’s main component in drug-containing serum was determined by UPLC-Q-TOF-MS/MS.

Results

The study found increased autophagy and decreased apoptosis in RA patients' synovial tissues compared to OA, which might link to higher HMGB1 levels and reduced Beclin 1-Bcl-2 binding. RPMTG effectively treated collagen-induced arthritis in rats by modulating Beclin 1, Bcl-2, and HMGB1 expression. It also reduced TNF-α-induced overproliferation in RA-FLSs and MH7A cells by lowering HMGB1 expression and enhancing the complex binding.

Conclusion

These findings emphasize the regulation of HMGB1 and Beclin 1-Bcl-2 complex in RA autophagy and apoptosis dysregulation, indicating RPMTG’s potential for treating RA.