首页 | 本学科首页   官方微博 | 高级检索  
   检索      


Ameloblast differentiation in the human developing tooth: Effects of extracellular matrices
Authors:Pingping He  Yan Zhang  Seong Oh Kim  Ralf J Radlanski  Kristin Butcher  Richard A Schneider  Pamela K DenBesten
Institution:1. Department of Orofacial Sciences, University of California, San Francisco, CA, USA;2. Department of Pediatric Dentistry, Oral Science Research Center, College of Dentistry, Yonsei University, Seoul, Republic of Korea;3. Charité Campus Benjamin Franklin, Center for Dental and Craniofacial Sciences, Institute for Orofacial Developmental Biology, Freie Universität Berlin, Germany;4. Department of Orthopedic Surgery, University of California, San Francisco, CA, USA
Abstract:Tooth enamel is formed by epithelially-derived cells called ameloblasts, while the pulp dentin complex is formed by the dental mesenchyme. These tissues differentiate with reciprocal signaling interactions to form a mature tooth. In this study we have characterized ameloblast differentiation in human developing incisors, and have further investigated the role of extracellular matrix proteins on ameloblast differentiation. Histological and immunohistochemical analyses showed that in the human tooth, the basement membrane separating the early developing dental epithelium and mesenchyme was lost shortly before dentin deposition was initiated, prior to enamel matrix secretion. Presecretary ameloblasts elongated as they came into contact with the dentin matrix, and then shortened to become secretory ameloblasts. In situ hybridization showed that the presecretory stage of odontoblasts started to express type I collagen mRNA, and also briefly expressed amelogenin mRNA. This was followed by upregulation of amelogenin mRNA expression in secretory ameloblasts. In vitro, amelogenin expression was upregulated in ameloblast lineage cells cultured in Matrigel, and was further up-regulated when these cells/Matrigel were co-cultured with dental pulp cells. Co-culture also up-regulated type I collagen expression by the dental pulp cells. Type I collagen coated culture dishes promoted a more elongated ameloblast lineage cell morphology and enhanced cell adhesion via integrin α2β1. Taken together, these results suggest that the basement membrane proteins and signals from underlying mesenchymal cells coordinate to initiate differentiation of preameloblasts and regulate type I collagen expression by odontoblasts. Type I collagen in the dentin matrix then anchors the presecretary ameloblasts as they further differentiate to secretory cells. These studies show the critical roles of the extracellular matrix proteins in ameloblast differentiation.
Keywords:
本文献已被 ScienceDirect 等数据库收录!
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号