Fig. 7: SP@M restores osteoimmunology homeostasis in CIA mouse models via NRF2/KEAP1 signaling pathways in vivo.

A Gene Ontology (GO) analysis of biological processes of the saline and SP@M groups (n = 3, biological repeats). B Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis between the saline and SP@M groups. C Gene set enrichment analysis (GSEA) of oxidative phosphorylation signaling pathway between the saline and SP@M groups. D Immunofluorescence analysis of KEAP1 and NRF2 in the focused area of ankle joints in RA mice paraffin section. Ta: Talus bone, Tb: Tibia bone, *synovium. Scale bar = 500 μm. E Integrated optical density (IOD)/DAPI quantification of KEAP1 and NRF2 as shown in panel D. F Immunofluorescence analysis of KEAP1, ubiquitin, and LC3 in the focused area of ankle joints in RA mice paraffin section. Ta Talus bone, Tb Tibia bone, *synovium. Scale bar = 500 μm. Zoomed-in scale bar = 25 μm. Six independent biological experiments were repeated. G SP@M regulates the macrophages and osteoclasts to suppress synovial inflammation and osteoclast differentiation, leading to inflammation antagonism, bone protection, and cartilage recovery in joints of RA mice in vivo. Mechanistically, SP@M suppresses KEAP1 via LC3-mediated autophagy and ubiquitin-mediated proteasomal degradation, promoting the nuclear translocation of NRF2 for antioxidant system activation (Created in BioRender. Yang, X. (2025) https://BioRender.com/vdfpv0u). All data presented as mean (SD) are from six biological replicates. Statistical analysis was performed using the one-way ANOVA followed by Tukey’s post-hoc test. The exact p-values were labeled.