Osteoprotegerin induces osteoclast pyroptosis via NF-κB signaling activation.

As a decoy receptor for RANKL, osteoprotegerin (OPG) suppresses osteoclast differentiation and can induce osteoclast death. Pyroptosis, an inflammatory programmed cell death, critically influences bone resorption, but its regulation remains unclear. This study investigated whether OPG induces pyroptosis in osteoclasts via the NF-κB pathway. Osteoclasts were treated with OPG and assessed for pyroptotic markers, NF-κB activation, morphology, and bone resorption. OPG dose-dependently decreased osteoclast viability, induced membrane rupture (LDH release, P < 0.01), and increased IL-18/IL-1β secretion (P < 0.01). Pyroptosis-related proteins (NLRP3, cleaved caspase-1, cleaved GSDMD) were upregulated. Transcriptomic analysis highlighted NF-κB pathway activation, confirmed by western blot (P-NF-κB, P-IκBα) and immunofluorescence (p65 nuclear translocation). Scanning electron microscopy directly visualized membrane rupture and pore formation, and bone resorption pit assays showed impaired resorptive function (P < 0.01). qRT-PCR validated downregulation of osteoclast marker genes and upregulation of pyroptosis-related genes. The NF-κB inhibitor QNZ blocked OPG-induced pyroptosis. In conclusion, OPG induces osteoclast pyroptosis through NF-κB activation, providing a potential therapeutic target for osteoclast-related bone disorders.