title: Do osteocytes contribute to phosphate homeostasis?
abstract: Osteocytes, the terminally differentiated cell of the osteoblast lineage, account for over 90% of all bone cells. Due to their relative inaccessibility within mineralized matrix, little is known regarding their specific functions in comparison to the well studied surface bone cells, osteoblasts and osteoclasts. Furthermore, bone is often viewed as a mineral reservoir that passively releases calcium and phosphate in response to hormones secreted from remote organs. Noncollagenous matrix proteins produced in osteocytes, such as dentin matrix protein 1 (DMP1), have also been viewed as inert scaffolds for calcium-phosphate deposition. Recent discoveries of new genetic mutations in human diseases and development of genetically engineered animal models challenge these classic paradigms, suggesting that the osteocyte plays an active role in both mineralization and total systemic phosphate regulation. In this review, we will focus on roles of osteocytes in mineralization and particularly in phosphate regulation via the DMP1- FGF23 pathway.
authors.affiliation: Department of Biomedical Sciences, Texas A&M Health Science Center, Baylor College of Dentistry, Dallas, Texas 75246, USA. jfeng@bcd.tamhsc.edu
authors.forename: Jian Q
authors.initials: JQ
authors.lastname: Feng
authors.forename: Ling
authors.initials: L
authors.lastname: Ye
authors.forename: Susan
authors.initials: S
authors.lastname: Schiavi
mesh_terms: D000818:Animals; D002113:Calcification, Physiologic; D019070:Cell Lineage; D002908:Chronic Disease; D016326:Extracellular Matrix Proteins / Q000502:physiology; D000089703:Fibroblast Growth Factor-23; D005346:Fibroblast Growth Factors / Q000502:physiology; D006023:Glycoproteins / Q000502:physiology; D006706:Homeostasis; D006801:Humans; D007674:Kidney Diseases / Q000209:etiology; D010011:Osteocytes / Q000378:metabolism*; D053402:PHEX Phosphate Regulating Neutral Endopeptidase / Q000502:physiology; D010710:Phosphates / Q000378:metabolism*; D010750:Phosphoproteins / Q000502:physiology
chemical_list: C513309:DMP1 protein, human; D016326:Extracellular Matrix Proteins; C000717427:FGF23 protein, human; D006023:Glycoproteins; C486579:MEPE protein, human; D010710:Phosphates; D010750:Phosphoproteins; D005346:Fibroblast Growth Factors; D000089703:Fibroblast Growth Factor-23; D053402:PHEX Phosphate Regulating Neutral Endopeptidase; C506231:PHEX protein, human