Rani C S, MacDougall M
Department of Pediatric Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, Texas, 78229-3900, USA.
Mol Cell Biol Res Commun. 2000 Mar;3(3):145-52. doi: 10.1006/mcbr.2000.0205.
Odontoblasts and osteoblasts produce similar highly mineralized extracellular matrices. In bone, osteoblasts/stromal cells regulate osteoclast (ocl) formation and bone resorption by producing factors like osteoprotegerin (OPG), osteoclast differentiating factor (ODF/RANKL), and macrophage colony-stimulating factor (M-CSF) that interact with hematopoietic ocl precursor cells. Using odontoblast and pulp cell lines, we detected a constitutive expression of OPG, RANKL, and M-CSF mRNA in both cell types. OPG and RANKL proteins were also detectable. In vivo, RANKL and OPG were localized to odontoblasts, ameloblasts, and pulp cells in developing mouse teeth by immunohistochemistry. In a coculture system, we found the dental cells to be inhibitory to ocl formation from spleen and bone marrow precursors, despite their production of osteoclast stimulatory factors. Our data indicate for the first time that dental cells express factors important in regulation of osteoclastogenesis and bone resorption. Since both stimulatory (RANKL, M-CSF) and inhibitory (OPG) factors are expressed, a balance between positive and negative factors may contribute to regulation of bone resorption.
成牙本质细胞和成骨细胞产生相似的高度矿化的细胞外基质。在骨组织中，成骨细胞/基质细胞通过产生诸如骨保护素（OPG）、破骨细胞分化因子（ODF/RANKL）和巨噬细胞集落刺激因子（M-CSF）等与造血破骨细胞前体细胞相互作用的因子来调节破骨细胞（ocl）的形成和骨吸收。利用成牙本质细胞系和牙髓细胞系，我们在两种细胞类型中均检测到OPG mRNA、RANKL mRNA和M-CSF mRNA的组成性表达。OPG蛋白和RANKL蛋白也可检测到。在体内，通过免疫组织化学发现RANKL和OPG定位于发育中小鼠牙齿的成牙本质细胞、成釉细胞和牙髓细胞中。在共培养系统中，我们发现牙细胞对来自脾脏和骨髓前体细胞的破骨细胞形成具有抑制作用，尽管它们产生破骨细胞刺激因子。我们的数据首次表明牙细胞表达在破骨细胞生成和骨吸收调节中起重要作用的因子。由于刺激因子（RANKL、M-CSF）和抑制因子（OPG）均有表达，正负因子之间的平衡可能有助于骨吸收的调节。
