Tumor necrosis factor receptor superfamily member 11B (Osteoprotegerin) (OPG)

Tumor necrosis factor receptor superfamily member 11B, commonly known as Osteoprotegerin (OPG), is a secreted decoy receptor that plays a fundamental role in bone homeostasis and vascular health [1, 3]. It functions primarily by binding to the Receptor Activator of Nuclear Factor kappa-B Ligand (RANKL), thereby preventing RANKL from interacting with its receptor RANK on the surface of osteoclast precursors [12, 14]. This inhibition effectively suppresses the differentiation, activation, and survival of osteoclasts, the cells responsible for bone resorption [1, 12]. Beyond its role in bone metabolism, OPG also acts as a decoy receptor for the TNF-related apoptosis-inducing ligand (TRAIL), which can influence cell survival and apoptosis in both normal and malignant tissues [11, 15]. Dysregulation of the OPG/RANKL/RANK axis is implicated in various pathologies, including osteoporosis, Paget disease, and bone metastases, as well as cardiovascular conditions like arterial calcification [6, 13, 16]. Therapeutic strategies involving OPG include the use of recombinant OPG proteins or monoclonal antibodies like denosumab, which mimics OPG's function by neutralizing RANKL [6, 25]. However, clinical application must consider OPG's dual role, as its inhibition of TRAIL-induced apoptosis may potentially promote tumor cell survival in certain contexts [1, 24].

Other names

OsteoprotegerinOsteoclastogenesis inhibitory factorOCIFTNFRSF11BTR1PDB5

Acts as a decoy receptor for RANKL (Receptor Activator of Nuclear Factor kappa-B Ligand), preventing its interaction with the RANK receptor on osteoclast precursors to inhibit bone resorption. It also functions as a decoy for TRAIL (TNF-related apoptosis-inducing ligand), thereby regulating apoptosis in various cell types.