title: Morphogenetic activity of silica and bio-silica on the expression of genes controlling biomineralization using SaOS-2 cells.
abstract: In a previous study (Schröder et al., J Biomed Mater Res B Appl Biomater 75:387-392, 2005) we demonstrated that human SaOS-2 cells, when cultivated on bio-silica matrices, respond with an increased hydroxyapatite deposition. In the present contribution we investigate if silica-based components (Na-silicate, tetraethyl orthosilicate [TEOS], silica-nanoparticles) (1) change the extent of biomineralization in vitro (SaOS-2 cells) and (2) cause an alteration of the expression of the genes amelogenin, ameloblastin, and enamelin, which are characteristic for an early stage of osteogenesis. We demonstrate that the viability of SaOS-2 cells was not affected by the silica-based components. If Na-silicate or TEOS was added together with ss-glycerophosphate, an organic phosphate donor, a significant increase in biomineralization was measured. Finally, expression levels of the amelogenin, ameloblastin, and enamelin genes were determined in SaOS-2 cells during exposure to the silica-based components. After exposure for 2 days, expression levels of amelogenin and enamelin strongly increased in response to the silica-based components, while no significant change was seen for ameloblastin. In contrast, exposure of SaOS-2 cells to ss-glycerophosphate resulted in increased expression of all three genes. We conclude that the levels of the structural molecules of the enamel matrix, amelogenin and enamelin, increase in the presence of silica-based components and substantially contribute to the extent of hydroxyapatite crystallite formation. These results demonstrate that silica-based components augment hydroxyapatite deposition in vitro and suggest that enzymatically synthesized bio-silica (via silicatein) might be a promising route for tooth reconstruction in vivo.
authors.affiliation: Institut für Physiologische Chemie, Abteilung Angewandte Molekularbiologie, Universität, Duesbergweg 6, D-55099 Mainz, Germany. wmueller@uni-mainz.de
authors.forename: Werner E G
authors.initials: WE
authors.lastname: Müller
authors.forename: Alexandra
authors.initials: A
authors.lastname: Boreiko
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Wang
authors.forename: Anatoli
authors.initials: A
authors.lastname: Krasko
authors.forename: Werner
authors.initials: W
authors.lastname: Geurtsen
authors.forename: Márcio Reis
authors.initials: MR
authors.lastname: Custódio
authors.forename: Thomas
authors.initials: T
authors.lastname: Winkler
authors.forename: Lada
authors.initials: L
authors.lastname: Lukić-Bilela
authors.forename: Thorben
authors.initials: T
authors.lastname: Link
authors.forename: Heinz C
authors.initials: HC
authors.lastname: Schröder
mesh_terms: D053523:Amelogenin / Q000235:genetics; D001672:Biocompatible Materials / Q000494:pharmacology* / Q000627:therapeutic use; D001861:Bone Regeneration / Q000187:drug effects / Q000502:physiology; D002113:Calcification, Physiologic / Q000187:drug effects* / Q000502:physiology; D045744:Cell Line, Tumor; D003743:Dental Enamel / Q000254:growth & development* / Q000378:metabolism; D003746:Dental Enamel Proteins / Q000235:genetics*; D018507:Gene Expression Regulation, Developmental / Q000187:drug effects* / Q000235:genetics; D005994:Glycerophosphates / Q000494:pharmacology; D006801:Humans; D008855:Microscopy, Electron, Scanning; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D017640:Silicates / Q000494:pharmacology / Q000627:therapeutic use; D012822:Silicon Dioxide / Q000494:pharmacology* / Q000627:therapeutic use; D014070:Tooth / Q000254:growth & development* / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: C490889:AMBN protein, human; D053523:Amelogenin; D001672:Biocompatible Materials; D003746:Dental Enamel Proteins; D005994:Glycerophosphates; D012333:RNA, Messenger; D017640:Silicates; C109069:enamel matrix proteins; C038456:tuftelin; D012822:Silicon Dioxide; C031463:beta-glycerophosphoric acid