Inflammasome Complexes: Crucial mediators in osteoimmunology and bone diseases

Inflammasome complexes play a vital role in the inflammatory response by producing interleukin-1β and inducing cell pyroptosis. During the long period of co-evolution of the skeletal and immune systems, inflammasome complexes bridged the bone-immune interaction, which is crucial for osteoimmunology and bone diseases. Additionally, the M1/M2 ratio, the Th17/Treg ratio, and osteoclastogenesis are regulated by inflammasomes in multiple bone diseases. Particularly, based on different disease features and inflammasome functions, osteoclastogenesis can be categorized as site-specific inflammation-related and system inflammation-related and is probably the most well-studied process in osteoimmunology. Research on inflammasomes includes multiple bone diseases and clinical therapies, including bisphosphonate-related osteonecrosis of jaws, periodontitis, arthritis, metal particle-induced osteolysis, bone fracture, osseointegration, and bone marrow inflammatory diseases. Neonatal-onset multisystem inflammatory disease is directly related to NLRP3 mutation. This review consolidates our basic knowledge about inflammasome structure and highlights the main cell subtypes and their functions in the bone-immune interaction. Furthermore, we discuss the inflammasome complexes and relevant bone diseases to provide insights for future studies on inflammasomes, osteoimmunology, and bone diseases.