title: Characteristics of minerals in vesicles produced by human osteoblasts hFOB 1.19 and osteosarcoma Saos-2 cells stimulated for mineralization.
abstract: Bone cells control initial steps of mineralization by producing extracellular matrix (ECM) proteins and releasing vesicles that trigger apatite nucleation. Using transmission electron microscopy with energy dispersive X-ray microanalysis (TEM-EDX) we compared the quality of minerals in vesicles produced by two distinct human cell lines: fetal osteoblastic hFOB 1.19 and osteosarcoma Saos-2. Both cell lines, subjected to osteogenic medium with ascorbic acid (AA) and β-glycerophosphate (β-GP), undergo the entire osteoblastic differentiation program from proliferation to mineralization, produce the ECM and spontaneously release vesicles. We observed that Saos-2 cells mineralized better than hFOB 1.19, as probed by Alizarin Red-S (AR-S) staining, tissue nonspecific alkaline phosphatase (TNAP) activity and by analyzing the composition of minerals in vesicles. Vesicles released from Saos-2 cells contained and were surrounded by more minerals than vesicles released from hFOB 1.19. In addition, there were more F and Cl substituted apatites in vesicles from hFOB 1.19 than in those from Saos-2 cells as determined by ion ratios. Saos-2 and h-FOB 1.19 cells revealed distinct mineralization profiles, indicating that the process of mineralization may proceed differently in various types of cells. Our findings suggest that TNAP activity is correlated with the relative proportions of mineral-filled vesicles and mineral-surrounded vesicles. The origin of vesicles and their properties predetermine the onset of mineralization at the cellular level.
authors.affiliation: Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Strzelecka-Kiliszek
authors.affiliation: Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland.
authors.forename: Lukasz
authors.initials: L
authors.lastname: Bozycki
authors.affiliation: Université de Lyon, 69622 Villeurbanne Cedex, France; Université Lyon 1, 69622 Villeurbanne Cedex, France; INSA de Lyon, 69622 Villeurbanne Cedex, France; CPE Lyon, 69622 Villeurbanne Cedex, France; ICBMS CNRS UMR 5246, 69622 Villeurbanne Cedex, France.
authors.forename: Saida
authors.initials: S
authors.lastname: Mebarek
authors.affiliation: Université de Lyon, 69622 Villeurbanne Cedex, France; Université Lyon 1, 69622 Villeurbanne Cedex, France; INSA de Lyon, 69622 Villeurbanne Cedex, France; CPE Lyon, 69622 Villeurbanne Cedex, France; ICBMS CNRS UMR 5246, 69622 Villeurbanne Cedex, France.
authors.forename: Rene
authors.initials: R
authors.lastname: Buchet
authors.affiliation: Department of Biochemistry, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 3 Pasteur Str., 02-093 Warsaw, Poland. Electronic address: s.pikula@nencki.gov.pl.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Pikula
mesh_terms: D001205:Ascorbic Acid / Q000494:pharmacology*; D002113:Calcification, Physiologic; D002454:Cell Differentiation / Q000187:drug effects; D045744:Cell Line, Tumor; D000067128:Extracellular Vesicles / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure; D005994:Glycerophosphates / Q000494:pharmacology*; D006801:Humans; D046529:Microscopy, Electron, Transmission; D008903:Minerals / Q000737:chemistry* / Q000378:metabolism; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism*; D013194:Staining and Labeling
chemical_list: D005994:Glycerophosphates; D008903:Minerals; D001205:Ascorbic Acid
keywords: Apatites; Mineralization; Osteoblasts; Osteosarcoma; Vesicles