McKee M D, Nanci A
Faculty of Dentistry, Department of Stomatology, University of Montreal, QC, Canada.
Ann N Y Acad Sci. 1995 Apr 21;760:177-89. doi: 10.1111/j.1749-6632.1995.tb44629.x.
Relative to other noncollagenous, extracellular matrix proteins in mineralized tissues, colloidal-gold immunocytochemistry has demonstrated that the ultrastructural distribution of osteopontin (OPN) is unique in that this protein preferentially accumulates at mineralized tissue interfaces. In bone, this protein is present as a major component of cell-matrix and matrix-matrix interfacial structures called cement lines and laminae limitantes. In the present article, the implications of this distinct tissue distribution are discussed in terms of the bone remodeling sequence, and a detailed account of the secretion, accumulation and potential role of OPN is presented and related to current theory on the cellular and extracellular matrix events associated with basic multicellular unit (BMU)-based bone remodeling. In this context, a proposal is made describing the production of this protein as one of the earliest, and latest, secretory activities of the osteoblastic lineage, and that this activity manifests itself morphologically as a cement line ('plane') and a lamina limitans, respectively, at bone matrix interfaces. When integrated with other, known functional characteristics of this protein, the present morphological and compositional data indicate that OPN in cement lines and laminae limitantes may participate in initial and late extracellular matrix organization and mineralization, matrix-matrix/mineral adhesion and/or cell adhesion at bone interfaces.
相对于矿化组织中的其他非胶原蛋白细胞外基质蛋白，胶体金免疫细胞化学研究表明，骨桥蛋白（OPN）的超微结构分布具有独特性，即该蛋白优先在矿化组织界面处积聚。在骨骼中，这种蛋白是称为黏合线和限制板的细胞-基质及基质-基质界面结构的主要成分。在本文中，将根据骨重塑序列来讨论这种独特组织分布的意义，并详细阐述OPN的分泌、积聚及潜在作用，并将其与当前关于基于基本多细胞单位（BMU）的骨重塑过程中细胞和细胞外基质事件的理论相关联。在此背景下，提出一种观点，即该蛋白的产生是成骨细胞谱系最早和最晚的分泌活动之一，并且这种活动在形态学上分别表现为骨基质界面处的黏合线（“平面”）和限制板。当与该蛋白的其他已知功能特性相结合时，目前的形态学和成分数据表明，黏合线和限制板中的OPN可能参与骨界面处细胞外基质的初始和晚期组织与矿化、基质-基质/矿物质黏附及/或细胞黏附。
