TLR4 and rheumatoid arthritis: Together, these above results demonstrated that HP@CEL displayed immunomodulatory effect including down-regulating the proinflammatory cytokines, harnessing the macrophage polarization, and mediating the macrophage and synovial fibroblast cross-talk transmitted through TLR4/MAPK/NF-κB signal pathway, thus effectively intervening the positive feedback of the chronic inflammation and improving the osteogenesis in RA.