title: Expression and roles of syndecan-4 in dental epithelial cell differentiation.
abstract: Syndecan-4 (SDC4), a transmembrane heparan sulfate proteoglycan, acts as a signal transducer. It affects the growth and differentiation of a number of tissues and organs. However, the specific mechanisms through which SDC4 regulates the differentiation of dental epithelial cells (amelogenesis) and tooth development remains largely unknown. In the present study, to identify the SDC4-regulated processes in dental epithelial cells, the SDC4 expression pattern was examined in mouse molar and postnatal incisor tooth germs during the late bell stage of development. Small interfering RNA (siRNA) was designed for this study and used to downregulate SDC4 expression in the rat dental epithelial cell line, HAT-7. The results revealed that SDC4 was mainly present in the oral epithelium, the dental epithelial cells of enamel organs in the molars and the cervical loops in the incisors. When the inner enamel epithelial cells gave rise to ameloblasts, however, the loss of SDC4 expression was evident. SDC4 was also expressed in stratum intermedium (SI) cells in the incisors and in dental mesenchymal cells adjacent to the cervical loops in molars (E18) and postnatal incisors. Fibroblast growth factor 10 (FGF10) promoted proliferation and slightly decreased cell differentiation. The knockdown of SDC4 using specific siRNA led to a decrease in cell proliferation and a highly significant increase in amelogenin, ameloblastin, kallikrein 4 and matrix metalloproteinase 20 expression, molecules that are known to participate in the formation of enamel. These effects were attenuated by FGF10, which upregulated SDC4 expression. Taken together, these results suggest that SDC4 participates in amelogenesis, and FGF10 may modulate dental epithelial cell behaviors through the regulation of SDC4 expression.
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Zhiling
authors.initials: Z
authors.lastname: Yan
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Yaling
authors.initials: Y
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Liang
authors.initials: L
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Zongting
authors.initials: Z
authors.lastname: Jiang
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Lian
authors.initials: L
authors.lastname: Feng
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Mei
authors.initials: M
authors.lastname: Yu
authors.affiliation: National Engineering Laboratory for Oral Regenerative Medicine, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Weihua
authors.initials: W
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, Sichuan 610041, P.R. China.
authors.forename: Weidong
authors.initials: W
authors.lastname: Tian
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D015536:Down-Regulation; D004847:Epithelial Cells / Q000166:cytology*; D051526:Fibroblast Growth Factor 10 / Q000235:genetics / Q000378:metabolism; D005346:Fibroblast Growth Factors / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D018507:Gene Expression Regulation, Developmental; D020868:Gene Silencing; D007180:Incisor / Q000166:cytology; D051379:Mice; D008810:Mice, Inbred C57BL; D009805:Odontogenesis / Q000502:physiology*; D034741:RNA, Small Interfering / Q000235:genetics; D051381:Rats; D015398:Signal Transduction; D053671:Syndecan-4 / Q000235:genetics / Q000378:metabolism*
chemical_list: C496465:Fgf10 protein, rat; D051526:Fibroblast Growth Factor 10; D034741:RNA, Small Interfering; C508306:Sdc4 protein, mouse; C508307:Sdc4 protein, rat; D053671:Syndecan-4; C503562:fibroblast growth factor 11, mouse; D005346:Fibroblast Growth Factors