Osteoprotegerin (OPG), also known as osteoclastogenesis inhibitory factor (OCIF) or tumour necrosis factor receptor superfamily member 11B (TNFRSF11B), is a cytokine receptor of the tumour necrosis factor (TNF) receptor superfamily encoded by the TNFRSF11B gene.
OPG was first discovered as a novel secreted TNFR related protein that played a role in the regulation of bone density and later for its role as a decoy receptor for receptor activator of nuclear factor kappa-B ligand (RANKL).[5] OPG also binds to TNF-related apoptosis-inducing ligand (TRAIL) and inhibits TRAIL induced apoptosis of specific cells, including tumour cells.[6] Other OPG ligands include syndecan-1, glycosaminoglycans, von Willebrand factor, and factor VIII-von Willebrand factor complex.[7]
OPG has been identified as having a role in tumour growth and metastasis,[6] heart disease,[8][9][10] immune system development and signalling,[7] mental health,[11] diabetes,[12] and the prevention of pre-eclampsia[13] and osteoporosis during pregnancy.[14]
^Nabipour I, Kalantarhormozi M, Larijani B, Assadi M, Sanjdideh Z (May 2010). "Osteoprotegerin in relation to type 2 diabetes mellitus and the metabolic syndrome in postmenopausal women". Metabolism. 59 (5): 742–7. doi:10.1016/j.metabol.2009.09.019. PMID19922962.
^Yano K, Shibata O, Mizuno A, Kobayashi F, Higashio K, Morinaga T, Tsuda E (October 2001). "Immunological study on circulating murine osteoprotegerin/osteoclastogenesis inhibitory factor (OPG/OCIF): possible role of OPG/OCIF in the prevention of osteoporosis in pregnancy". Biochemical and Biophysical Research Communications. 288 (1): 217–24. doi:10.1006/bbrc.2001.5745. PMID11594776.