The NLRP12 Osteoimmune Checkpoint: Coordinating Inflammatory Signaling and Bone Remodeling.

Bone remodeling is increasingly recognized as an immunologically regulated process in which inflammatory signaling governs the balance between bone formation and resorption. While extensive efforts have focused on pathways that promote osteoclastogenesis, endogenous mechanisms that restrain inflammatory bone destruction remain less well defined. Here, we propose NLRP12 as a previously underappreciated osteoimmune checkpoint that integrates innate immune regulation with skeletal homeostasis. Emerging evidence demonstrates that NLRP12 suppresses NF-κB and MAPK signaling, antagonizes NLRP3 inflammasome activation, and limits the production of osteoclastogenic cytokines, thereby constraining pathological bone resorption. Beyond its direct effects on osteoclast precursors, NLRP12 may shape the broader bone marrow immune niche through regulation of macrophages, dendritic cells, neutrophils, immunometabolic pathways, and host-microbiota interactions. We synthesize current knowledge linking NLRP12 to osteoclast differentiation, inflammatory bone diseases, and osteoimmune communication, and highlight key unanswered questions regarding its functions in osteoblasts, osteocytes, and skeletal aging. By framing NLRP12 as an important regulator of inflammatory tone within the skeletal microenvironment, we introduce an osteoimmune checkpoint paradigm that provides new conceptual insights into the pathogenesis of osteolytic disorders and identifies opportunities for therapeutic intervention.