title: The P2X7 receptor: a key player in immune-mediated bone loss?
abstract: Inflammatory diseases are often multiorganic diseases with manifestations not related directly to the primary affected organ. They are often complicated by a generalized bone loss that subsequently leads to osteoporosis and bone fractures. The exact mechanism for the accompanying bone loss is not understood in full detail, but factors such as glucocorticoid treatment, immobilization, malnutrition, and insufficient intake of vitamin D play a role. However, it has become evident that the inflammatory process itself is involved and the resulting bone loss is termed immune-mediated bone loss. It stems from an increase in bone resorption and the pro-inflammatory cytokines tumor necrosis factor alpha and interleukin 1 beta and has been shown to not only mediate the inflammatory response but also to strongly stimulate bone degradation. The purinergic P2X7 receptor is central in the processing of these two cytokines and in the initiation of the inflammatory response, and it is a key molecule in the regulation of both bone formation and bone resorption. The aim of this review is therefore to provide evidence-based novel hypotheses of the role of ATP-mediated purinergic signalling via the P2X7 receptor in immune-mediated bone loss and -osteoporosis.
authors.affiliation: Research Center for Ageing and Osteoporosis, Departments of Medicine and Diagnostics, Glostrup Hospital, 2600 Glostrup, Denmark.
authors.forename: Torben Madsen
authors.identifier: 0000-0002-8743-3006
authors.initials: TM
authors.lastname: Kvist
authors.affiliation: Research Center for Ageing and Osteoporosis, Departments of Medicine and Diagnostics, Glostrup Hospital, 2600 Glostrup, Denmark ; Faculty of Health Sciences, Copenhagen University, 2100 Copenhagen Ø, Denmark.
authors.forename: Peter
authors.identifier: 0000-0002-0483-8594
authors.initials: P
authors.lastname: Schwarz
authors.affiliation: Research Center for Ageing and Osteoporosis, Departments of Medicine and Diagnostics, Glostrup Hospital, 2600 Glostrup, Denmark ; Faculty of Health Sciences, Copenhagen University, 2100 Copenhagen Ø, Denmark.
authors.forename: Niklas Rye
authors.initials: NR
authors.lastname: Jørgensen
mesh_terms: D000818:Animals; D016207:Cytokines / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D010024:Osteoporosis / Q000276:immunology / Q000378:metabolism*; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism*
chemical_list: D016207:Cytokines; D058486:Receptors, Purinergic P2X7