Tsuchiya M, Tye C E, Sharma R, Smith C E, Bartlett J D
Department of Cytokine Biology, The Forsyth Institute, and Department of Developmental Biology, Harvard School of Dental Medicine, 140 The Fenway, Boston, MA 02115, USA.
J Dent Res. 2008 Nov;87(11):1058-62. doi: 10.1177/154405910808701115.
Ameloblasts progress through defined stages of development as enamel forms on teeth. Pre-secretory ameloblasts give rise to tall columnar secretory ameloblasts that direct the enamel to achieve its full thickness. During the maturation stage, the ameloblasts shorten and direct the enamel to achieve its final hardened form. Here we ask how the volume of selected ameloblast organelles changes (percent volume per ameloblast) as ameloblasts progress through six defined developmental stages. We demonstrate that mitochondria volume peaks during late maturation, indicating that maturation-stage ameloblasts maintain a high level of metabolic activity. Also, the endoplasmic reticulum (ER) volume changes significantly as a function of developmental stage. This prompted us to ask if X-box-binding protein-1 (XBP1) plays a role in regulating ameloblast ER volume, as has been previously demonstrated for secretory acinar cells and for plasma cell differentiation. We demonstrate that Xbp1 expression correlates positively with percent volume of ameloblast ER.
随着牙齿上釉质的形成，成釉细胞经历特定的发育阶段。分泌前成釉细胞分化为高柱状的分泌性成釉细胞，后者引导釉质形成其完整厚度。在成熟阶段，成釉细胞变短并引导釉质形成其最终的硬化形式。在这里，我们探讨在成釉细胞经历六个特定发育阶段时，选定的成釉细胞器的体积（每个成釉细胞的体积百分比）如何变化。我们证明，线粒体体积在成熟后期达到峰值，这表明成熟阶段的成釉细胞维持高水平的代谢活性。此外，内质网（ER）体积随发育阶段发生显著变化。这促使我们探究X盒结合蛋白1（XBP1）是否像先前在分泌性腺泡细胞和浆细胞分化中所证明的那样，在调节成釉细胞内质网体积中发挥作用。我们证明，Xbp1表达与成釉细胞内质网的体积百分比呈正相关。
