S100A4 upregulation suppresses tissue ossification and enhances matrix degradation in experimental periodontitis models.
OBJECTIVE
S100A4, also known as fibroblast-specific protein 1 or metastasin 1, is not only highly expressed in growth-stimulated cultured cells and metastatic tumor cells, but also in the periodontal ligament. The aim of this study was to investigate the roles of S100A4 in the pathogenesis of periodontitis and its regulatory mechanisms in inflammatory milieu.


METHODS
Experimental periodontitis was induced in rats by submarginal silk ligatures. TRAP activity and S100A4 expression in periodontal ligaments were examined using immunohistochemistry and immunofluorescence methods. IL-1β-treated human periodontal ligament cells (hPDLCs) were used as in vitro model of experimental periodontitis. S100A4 mRNA and protein were assessed using qRT-PCR and Western blot, respectively. hPDLCs were transfected with either S100A4 overexpression plasmids or shRNAs plasmids. The mineralization in hPDLCs was evaluated with a 12-d osteogenic induction assay, and the expression of ALP, OCN, MMP-2 and MMP-13 was analyzed by qRT-PCR.


RESULTS
In the periodontal ligaments of rats with experimental periodontitis, TRAP activity and S100A4 protein staining were considerably more intense compared with those in the control rats. Treatment of hPDLCs with IL-1β (10, 50 and 100 ng/mL) dose-dependently increased the mRNA and protein levels of S100A4. Transfection with shRNAs markedly increased mineralized nodule formation and the osteogenic-related markers ALP and OCN levels in hPDLCs, whereas the overexpression of S100A4 significantly reduced mineralized nodule formation, and increased the matrix degradation enzymes MMP-2 and MMP-13 levels in hPDLCs.


CONCLUSIONS
S100A4 is upregulated in the experimental rat periodontitis and in IL-1β-treated hPDLCs, where S100A4 suppresses osteogenic differentiation and enhances matrix degradation. Thus, S100A4 is a potential target for the treatment of periodontitis.
Shanghai Engineering Research Center of Tooth Restoration and Regeneration, School of Stomatology, Tongji University, Shanghai 200072, China.
Min
M
Zhou
Shanghai East Hospital, The Institute for Biomedical Engineering and Nano Science, Tongji University School of Medicine, Tongji University, Shanghai 200092, China.
Zhuo-quan
ZQ
Li
Shanghai Engineering Research Center of Tooth Restoration and Regeneration, School of Stomatology, Tongji University, Shanghai 200072, China.
Zuo-lin
ZL
Wang
D000328:Adult; D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology; D008297:Male; D010012:Osteogenesis; D010513:Periodontal Ligament / Q000166:cytology* / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D010518:Periodontitis / Q000235:genetics* / Q000276:immunology / Q000473:pathology; D017207:Rats, Sprague-Dawley; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins / Q000032:analysis / Q000235:genetics* / Q000276:immunology; D014162:Transfection; D015854:Up-Regulation
D053583:Interleukin-1beta; D000071999:S100 Calcium-Binding Protein A4; D009418:S100 Proteins; C499412:S100a4 protein, rat; C077591:S100A4 protein, human