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P2X7 receptor drives osteoclast fusion by increasing the extracellular adenosine concentration
Author(s) -
Pellegatti Patrizia,
Falzoni Simonetta,
Donvito Giovanna,
Lemaire Irma,
Di Virgilio Francesco
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.10-169854
Subject(s) - osteoclast , adenosine , microbiology and biotechnology , purinergic signalling , extracellular , purinergic receptor , biology , cell fusion , adenosine deaminase , rankl , receptor , adenosine receptor , activator (genetics) , endocrinology , biochemistry , cell , agonist
Defects in bone homeostasis are a major health problem. Osteoclast differentiation and activation have a crucial role in bone remodeling in health and disease. Osteoclasts are bone‐resorbing cells derived from mononuclear phagocyte progenitors. The key event in osteoclast formation is fusion of mononucleate precursors to form mature multinucleated osteclasts. Here we provide evidence of an absolute requirement for the P2X7 receptor, ATP release, and adenosine signaling in human osteoclast formation, as shown by the following findings: macrophage‐colony stimulating factor/receptor activator for nuclear fac‐tor‐κB ligand (M‐CSF/RANKL)‐stimulated fusion of human monocytes is fully prevented by an anti‐P2X7 mAb, by specific P2X7 pharmacological antagonists, or by inhibition of CD39/NTPDase;fusion‐competent monocytes release ATP via the P2X7 receptor; accelerated degradation of released ATP by addition of either apyrase or hexokinase strongly increases fusion; removal of extracellular adenosine by adenosine deaminase blocks, while addition of exogenous adenosine strongly potentiates, fusion; and pharmacologic stimulation of the adenosine A2A receptor increases, while selective A2A blockade inhibits, fusion. These results show that the purinergic axis plays a crucial and as yet undescribed role in osteoclast formation and reconcile previous evidence advocating a keyrole for either ATP or adenosine receptors in multinucleated giant cell formation.—Pellegatti, P., Falzoni, S., Donvito, G., Lemaire, I., Di Virgilio, F. P2X7 receptor drives osteoclast fusion by increasing the extracellular adenosine concentration. FASEB J. 25, 1264–1274 (2011). www.fasebj.org