title: Excess magnesium inhibits excess calcium-induced matrix-mineralization and production of matrix gla protein (MGP) by ATDC5 cells.
abstract: We found that excessive extracellular Ca2+ and/or Mg2+ affected the process of matrix mineralization and glycosaminoglycan (GAG) production by cells of the prechondrogenic cell line, ATDC5. Excess Ca2+ induced both matrix mineralization and GAG production in the cells. On the other hand, excess Mg2+ reduced this Ca2+-mediated rise in both mineralization and GAG production in them. Next we measured the mRNA levels of cartilage-associated genes such as calcium-sensing receptor (CaSR), matrix gla protein (MGP), bone gla protein (BGP), and Runt-related transcription factor 2 (Runx2) in ATDC5 cells. Excess Ca2+ increased the MGP, BGP, and CaSR mRNA levels, and excess Mg2+ reduced the Ca2+-induced increase in the MGP mRNA level in the cells. The changes in the MGP mRNA level paralleled those in the MGP protein level. These data show that Ca2+ and Mg2+ regulated the matrix mineralization positively and negatively, respectively, in ATDC5 cells and suggest that excess Mg2+ might inhibit the excess Ca2+-promoted mineralization mediated by MGP induction in chondrocytes.
authors.affiliation: Department of Food Functional Science, Graduate School of Pharmacology, Josai University, Sakado, Saitama 3500295, Japan.
authors.forename: Sachie
authors.initials: S
authors.lastname: Nakatani
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mano
authors.forename: I M
authors.initials: IM
authors.lastname: Ryanghyok
authors.forename: Jun
authors.initials: J
authors.lastname: Shimizu
authors.forename: Masahiro
authors.initials: M
authors.lastname: Wada
mesh_terms: D000818:Animals; D002118:Calcium / Q000037:antagonists & inhibitors / Q000502:physiology*; D002135:Calcium-Binding Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D045744:Cell Line, Tumor; D005109:Extracellular Matrix / Q000378:metabolism*; D016326:Extracellular Matrix Proteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis*; D006025:Glycosaminoglycans / Q000096:biosynthesis; D006801:Humans; D008274:Magnesium / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D000097568:Matrix Gla Protein
chemical_list: D002118:Calcium; D002135:Calcium-Binding Proteins; D016326:Extracellular Matrix Proteins; D006025:Glycosaminoglycans; D008274:Magnesium; D000097568:Matrix Gla Protein