The nature and functional significance of dentin extracellular matrix proteins.
The nature and functional significance of dentin extracellular matrix proteins.
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DOI：
10.1387/ijdb.7626404
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发表时间：
1995-02
期刊：
影响因子：
--
通讯作者：
W. Butler;H. Ritchie
中科院分区：
文献类型：
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作者：
W. Butler;H. Ritchie
成牙本质细胞负责形成前牙本质，当磷灰石晶体形成和纤维基质矿化时，前牙本质转变为牙本质。成牙本质细胞是一种特殊的细胞，它合成和分泌一组独特的非胶原蛋白(NCP)，以及主要由I型胶原组成的胶原基质。NCP由牙本质特异性和矿化组织特异性蛋白质以及在各种组织中发现的其他蛋白质组成。到目前为止，已发现三种牙本质特异性蛋白：牙本质磷酸蛋白(DPP)，又称磷酸化蛋白，AG1(牙本质基质蛋白1，Dmp1)和牙本质唾液蛋白(DSP)。DPP似乎是由成牙本质细胞形成的，并在短时间内出现在矿化前沿。它可能是通过成牙本质细胞过程分泌的。DPP与胶原结合，并可能启动磷灰石晶体的形成。DPP的第二个功能似乎是与生长中的磷灰石晶体的100面结合，并抑制或减缓其生长；因此，DPP可能起到双重作用，启动矿化，然后影响晶体生长，可能还影响晶体的习性。虽然AG1或DSP还没有被认为具有功能，但它们应该被证明是成牙本质细胞表型的重要标志。最近一个独特的发现是，两个独立的基因似乎编码不止一个DSP mRNA；其他转录本可能是差异剪接的结果。成骨细胞和成牙本质细胞表达的矿化组织特异性蛋白的例子是骨涎蛋白(BSP)和骨钙素。一些在成骨细胞、成牙本质细胞和其他组织中表达的NCPs包括骨桥蛋白(OPN)和含有蛋白多糖、核心蛋白聚糖和二聚糖的硫酸软骨素。我们认为，组织和培养中成牙本质细胞的特征应该依赖于上述NCP及其mRNAs的标记集的使用。类似的方法通常用于成骨细胞的研究。最后，牙本质(像骨一样)含有其他分子，如生长因子和血清衍生蛋白，在基质中发现；这一发现尚未具有功能意义。未来的实验将集中于阐明胶原纤维网络和NCPs的三维结构，以确定它们与矿化的关系。成牙本质细胞在控制细胞外事件中所起的作用，例如通过选择性的分泌途径，将需要仔细研究。
Odontoblasts are responsible for formation of predentin, which is transformed to dentin when apatite crystals are formed and the fibrillar matrix becomes mineralized. Odontoblasts are specialized cells that synthesize and secrete a unique set of non-collagenous proteins (NCPs), as well as the collagenous matrix largely comprised of type I collagen. The NCPs consist of dentin specific and mineralized tissue specific proteins, as well as other proteins that are found in a variety of tissues. Three dentin specific proteins have been recognized to date: dentin phosphoprotein (DPP), also called phosphophoryn, AG1 (dentin matrix protein 1, Dmp1) and dentin sialoprotein (DSP). DPP appears to be made by odontoblasts and appears at the mineralization front within a short time. It may be secreted via odontoblastic processes. DPP binds to collagen and potentially initiates formation of apatite crystals. A second DPP function appears to be to bind to the 100 face of growing apatite crystals and to inhibit or slow their growth; thus, DPP may play a dual role by initiating mineralization and then affecting the crystal growth and perhaps the habit of the crystals. Although no function has been ascribed to AG1 or DSP, they should prove to be important markers for the odontoblast phenotype. A recent unique finding is that two separate genes appear to code for more than one DSP mRNA; other transcripts may result from differential splicing. Examples of mineralized tissue specific proteins expressed by osteoblasts as well as odontoblasts are bone sialoprotein (BSP) and osteocalcin. Some NCPs expressed by osteoblasts, odontoblasts and several other tissues include osteopontin (OPN) and the chondroitin sulfate containing proteoglycans, decorin and biglycan. We propose that characterization of odontoblasts in tissues and cultures should rely upon utilization of sets of markers for the above NCPs and their mRNAs. Similar approaches are commonly used in investigations on osteoblasts. Finally, dentin (like bone) contains other molecules such as growth factors, and serum derived proteins, found within the matrix; no functional significance has yet been placed upon this finding. Future experiments should focus upon the elucidation of the three dimensional structures of the collagenous fibrillar network and of the NCPs to determine the relationships to mineralization. The role played by odontoblasts in controlling extracellular events, such as by selective secretory routes, will require careful exploration.