title: Extracellular nucleotides, cartilage stress, and calcium crystal formation.
abstract: Nucleotides are released by chondrocytes at rest and in response to mechanical stimulation. Extracellular nucleotides are metabolized by a variety of ectoenzymes, producing free phosphate (Pi) or pyrophosphate (PPi) and promoting matrix mineralization. Ectoenzymes are differentially localized in cartilage and may be co-released with nucleotides during mechanical stimulation. Extracellular nucleotides can also serve as substrates and/or modulators of enzymes such as tissue transglutaminase and ecto-protein kinases that modify matrix proteins and regulate crystal deposition or growth. Understanding the evolution of osteoarthritis and calcium crystal deposition diseases will require clearer knowledge of the functions of nucleotides and ectoenzymes in the cartilage extracellular matrix.
authors.affiliation: Thurston Arthritis Research Center, University of North Carolina, North Carolina 27599-7280, USA. rgraff@med.unc.edu
authors.forename: Ronald D
authors.initials: RD
authors.lastname: Graff
authors.forename: Maryse
authors.initials: M
authors.lastname: Picher
authors.forename: Greta M
authors.initials: GM
authors.lastname: Lee
mesh_terms: D000818:Animals; D002114:Calcinosis / Q000209:etiology / Q000503:physiopathology*; D002131:Calcium Pyrophosphate / Q000378:metabolism*; D002358:Cartilage, Articular / Q000503:physiopathology*; D002805:Chondrocalcinosis / Q000201:enzymology* / Q000503:physiopathology*; D019902:Chondrocytes / Q000378:metabolism / Q000502:physiology; D003460:Crystallization; D005110:Extracellular Space; D006801:Humans; D008297:Male; D009711:Nucleotides / Q000378:metabolism* / Q000502:physiology; D012307:Risk Factors; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index
chemical_list: D009711:Nucleotides; D002131:Calcium Pyrophosphate