title: Fluoride promotes viability and differentiation of osteoblast-like Saos-2 cells via BMP/Smads signaling pathway.
abstract: The BMP/Smad signaling pathway plays an important role in the viability and differentiation of osteoblast; however, it is not clear whether this pathway is involved in the fluoride-induced osteoblast differentiation. In this study, we investigated the role of BMP/Smad signaling pathway in fluoride-induced osteoblast-like Saos-2 cells differentiation. Cells were exposed to fluoride of different concentrations (0, 0.1, 0.2, 0.4, 0.8, and 1.6 mM), and cell proliferation was determined using WST assays. The expression of osteoblast marker genes such as osteocalcin (BGP) and bone alkaline phosphatase (BALP) were detected by qRT-PCR. We found that fluoride enhanced the proliferation of Saos-2 cells in a dose-dependent manner and 0.2 mM of fluoride resulted in a higher expression of osteoblast marker genes. In addition, immunofluorescence analysis showed that the promotion effects of 0.2 mM of fluoride on Saos-2 cells differentiation were associated with the activation of the BMP/Smad pathway. Expression of phosphorylated Smad1/5(p-Smad1/5) was higher in cells exposed to 0.2 mM of fluoride. Plasmid expression vectors encoding the short hairpin RNA (shRNA) targeting Smad4 gene were used to block the BMP/Smad pathway, which resulted in a significantly reduced expression of BGP and BALP as well as their corresponding mRNA. The mRNA levels after transfection remained low even in the presence of fluoride. The present results reveal that BMP/Smad signaling pathway was altered during the period of osteogenesis, and that the activities of p-Smad1/5 were required for Saos-2 cells viability and differentiation induced by fluoride.
authors.affiliation: Department of Endemic Diseases Control and Prevention, Hangzhou Center for Disease Control and Prevention, Hangzhou, Zhejiang, China.
authors.forename: Liangliang
authors.initials: L
authors.lastname: Huo
authors.forename: Kangkang
authors.initials: K
authors.lastname: Liu
authors.forename: Junrui
authors.initials: J
authors.lastname: Pei
authors.forename: Yanmei
authors.initials: Y
authors.lastname: Yang
authors.forename: Yan
authors.initials: Y
authors.lastname: Ye
authors.forename: Yang
authors.initials: Y
authors.lastname: Liu
authors.forename: Jing
authors.initials: J
authors.lastname: Sun
authors.forename: Hepeng
authors.initials: H
authors.lastname: Han
authors.forename: Weimin
authors.initials: W
authors.lastname: Xu
authors.forename: Yanhui
authors.initials: Y
authors.lastname: Gao
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002454:Cell Differentiation / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D018613:Microscopy, Confocal; D010006:Osteoblasts / Q000187:drug effects / Q000378:metabolism; D015675:Osteocalcin / Q000235:genetics; D012516:Osteosarcoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation / Q000187:drug effects; D034622:RNA Interference; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D051785:Smad Proteins / Q000235:genetics / Q000378:metabolism*; D051898:Smad1 Protein / Q000378:metabolism; D051901:Smad4 Protein / Q000235:genetics / Q000378:metabolism; D051902:Smad5 Protein / Q000378:metabolism; D012969:Sodium Fluoride / Q000494:pharmacology*
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D051785:Smad Proteins; D051898:Smad1 Protein; D051901:Smad4 Protein; D051902:Smad5 Protein; D015675:Osteocalcin; D012969:Sodium Fluoride; D000469:Alkaline Phosphatase
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