Dysregulation of ectonucleotidase-mediated extracellular adenosine during postmenopausal bone loss

• Published in: Science advances Vol. 5; no. 8; p. eaax1387
• Main Authors: Shih, Yu-Ru V, Liu, Mengqian, Kwon, Seong Keun, Iida, Masayuki, Gong, Ya, Sangaj, Nivedita, Varghese, Shyni
• Format: Journal Article
• Language: English
• Published: United States American Association for the Advancement of Science 01.08.2019
• Subjects: Adenosine - metabolism; Adenosine A2 Receptor Agonists - pharmacology; Adenosine Triphosphatases - metabolism; Animals; Biomarkers; Cell Biology; Cell Membrane; Cells, Cultured; Diseases and Disorders; Estrogen Receptor alpha - genetics; Estrogen Receptor alpha - metabolism; Extracellular Space - metabolism; Gene Expression; Humans; Mice; Osteoclasts - metabolism; Osteogenesis - genetics; Osteoporosis, Postmenopausal - diagnosis; Osteoporosis, Postmenopausal - etiology; Osteoporosis, Postmenopausal - metabolism; Osteoporosis, Postmenopausal - prevention & control; Receptor, Adenosine A2B - metabolism; SciAdv r-articles; X-Ray Microtomography
• ISSN: 2375-2548; 2375-2548
• DOI: 10.1126/sciadv.aax1387

Adenosine and its receptors play a key role in bone homeostasis and regeneration. Extracellular adenosine is generated from CD39 and CD73 activity in the cell membrane, through conversion of adenosine triphosphate to adenosine monophosphate (AMP) and AMP to adenosine, respectively. Despite the relevance of CD39/CD73 to bone health, the roles of these enzymes in bona fide skeletal disorders remain unknown. We demonstrate that CD39/CD73 expression and extracellular adenosine levels in the bone marrow are substantially decreased in animals with osteoporotic bone loss. Knockdown of estrogen receptors ESR1 and ESR2 in primary osteoprogenitors and osteoclasts undergoing differentiation showed decreased coexpression of membrane-bound CD39 and CD73 and lower extracellular adenosine. Targeting the adenosine A2B receptor using an agonist attenuated bone loss in ovariectomized mice. Together, these findings suggest a pathological association of purine metabolism with estrogen deficiency and highlight the potential of A2B receptor as a target to treat osteoporosis.