title: Zinc deprivation inhibits extracellular matrix calcification through decreased synthesis of matrix proteins in osteoblasts.
abstract: METHODS
  Zinc is implicated as an activator for bone formation, however, its influence on bone calcification has not been reported. This study examined how zinc regulates the bone matrix calcification in osteoblasts.
  
  
  RESULTS
  Two osteoblastic MC3T3-E1 cell subclones (SC 4 and SC 24 as high and low osteogenic differentiation, respectively) were cultured in normal osteogenic (OSM), Zinc deficient (Zn-, 1 μM), or adequate (Zn+, 15 μM) media up to 20 days. Cells (SC 4) were also supplemented with (50 μg/mL) or no ascorbic acid (AA) in combination with Zinc treatment. Zn- decreased collagen synthesis and matrix accumulation. Although AA is essential for collagen formation, its supplementation could not compensate for Zinc deficiency-induced detrimental effects on extracellular matrix mineralization. Zn- also decreased the medium and cell layer alkaline phosphatase ALP activity. This decreased ALP activity might cause the decrease of Pi accumulation in response to Zn-, as measured by von Kossa staining. Ca deposition in cell layers, measured by Alizarin red S staining, was also decreased by Zn(-) .
  
  
  CONCLUSIONS
  Our findings suggest that zinc deprivation inhibits extracellular matrix calcification in osteoblasts by decreasing the synthesis and activity of matrix proteins, type I collagen and ALP, and decreasing Ca and Pi accumulation. Therefore zinc deficiency can be considered as risk factor for poor extracellular matrix calcification.
authors.affiliation: Department of Food Science and Nutrition, Andong National University, 388 Songchundong,Andong, Kyungbook, South Korea.
authors.forename: Ethel H
authors.initials: EH
authors.lastname: Alcantara
authors.forename: Ria-Ann R
authors.initials: RA
authors.lastname: Lomeda
authors.forename: Joerg
authors.initials: J
authors.lastname: Feldmann
authors.forename: Graeme F
authors.initials: GF
authors.lastname: Nixon
authors.forename: John H
authors.initials: JH
authors.lastname: Beattie
authors.forename: In-Sook
authors.initials: IS
authors.lastname: Kwun
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D002113:Calcification, Physiologic / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D024042:Collagen Type I / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects*; D015032:Zinc / Q000172:deficiency* / Q000494:pharmacology / Q000502:physiology
chemical_list: D024042:Collagen Type I; D000469:Alkaline Phosphatase; D015032:Zinc; D001205:Ascorbic Acid; D002118:Calcium