Chitosan-based self-healing thermosensitive hydrogel loaded with siHMGB1 for treatment of rheumatoid arthritis via macrophage repolarization

Rheumatoid arthritis (RA) is a prevalent autoimmune disease marked by immune cell activation, particularly macrophages. An imbalance between pro-inflammatory M1 and anti-inflammatory M2 macrophages causes synovial inflammation and joint damage, worsening RA. This study presents a biomacromolecular hydrogel delivery system with apoferritin nanoparticles for effective delivery of small interfering high mobility group protein (siHMGB1). The system was designed to promote the polarization of M1 macrophages to the M2 phenotype by downregulating the HMGB1/TLR4/NF-kappa B-p65 signaling pathway, offering a potential therapeutic approach for the treatment of RA. The oxidized chondroitin sulfate - chitosan - sodium glycerol (3 - phosphate - Fn/siHMGB1 (OCF/siHMGB1) hydrogel system possessed temperature-sensitive and self-healing properties, enabling the sustained, stable, and efficient release of siHMGB1 at the affected joint. After effective uptake by macrophages, siHMGB1 could effectively repolarize M1-phenotype macrophages to M2-phenotype via the HMGB1/TLR4/NF kappa B-p65 signaling pathway both in vitro and in vivo. Additionally, it suppressed the release of pro-inflammatory cytokines and upregulated anti-inflammatory cytokines, which significantly blocked the TLR4/p65-mediated inflammatory signaling. In conclusion, the siHMGB1-loaded hydrogel delivery system designed in this study is effective in treating RA and highlights the potential of gene therapy to induce repolarization of M1 to M2 macrophages for RA treatment.