Ouyang H, McCauley L K, Berry J E, D'Errico J A, Strayhorn C L, Somerman M J
Department of Periodontics/Prevention/Geriatrics, The University of Michigan, Ann Arbor, MI 48109-1078, USA.
Arch Oral Biol. 2000 Apr;45(4):293-303. doi: 10.1016/s0003-9969(99)00142-9.
Cementum is an essential component of the periodontium, but the mechanisms involved in regulating the activity of this tissue are poorly understood. As one approach to better defining the cellular and molecular properties of cementum and the associated ligament, immortalized murine cell populations expressing gene markers associated with both cementoblasts (CM) and periodontal ligament cells (PDL), termed CM/PDL cells, were established. To further characterize these cells, their responsiveness to parathyroid hormone (PTH) and parathyroid hormone-related protein (PTHrP) was examined. CM/PDL cells were tested for the presence of steady state PTH-1 receptor mRNA using Northern blot analysis. In addition, the ability of PTH and PTHrP to stimulate cAMP production and c-fos mRNA expression in CM/PDL cells was determined, using a cAMP-binding assay and northern blot hybridization, respectively. Rat osteosarcoma cells (ROS 17/2.8) were used as a positive control and human periodontal ligament cells as a negative control. Northern blot analysis demonstrated that cells within the CM/PDL cell population expressed PTH-1 receptor mRNA. Both PTH (1-34) and PTHrP (1-34) increased cAMP and c-fos mRNA in CM/PDL cells. Furthermore, PTHrP treatment for either 24 or 48 h downregulated expression of transcripts for bone sialoprotein, osteocalcin and PTH-1 receptor by CM/PDL cells and abolished CM/PDL cell-mediated mineralization in vitro. These results indicate that cells within the CM/PDL population are targets for PTH and PTHrP action and that PTHrP may play an important part in regulating the biomineralization of cementum.
牙骨质是牙周组织的重要组成部分，但调节该组织活性的机制仍知之甚少。作为更好地定义牙骨质及相关韧带的细胞和分子特性的一种方法，建立了表达与成牙骨质细胞（CM）和牙周韧带细胞（PDL）相关基因标记的永生化小鼠细胞群体，称为CM/PDL细胞。为了进一步表征这些细胞，检测了它们对甲状旁腺激素（PTH）和甲状旁腺激素相关蛋白（PTHrP）的反应性。使用Northern印迹分析检测CM/PDL细胞中稳态PTH-1受体mRNA的存在。此外，分别使用cAMP结合测定法和Northern印迹杂交法测定PTH和PTHrP刺激CM/PDL细胞中cAMP产生和c-fos mRNA表达的能力。大鼠骨肉瘤细胞（ROS 17/2.8）用作阳性对照，人牙周韧带细胞用作阴性对照。Northern印迹分析表明，CM/PDL细胞群体中的细胞表达PTH-1受体mRNA。PTH（1-34）和PTHrP（1-34）均增加了CM/PDL细胞中的cAMP和c-fos mRNA。此外，PTHrP处理24或48小时可下调CM/PDL细胞中骨唾液蛋白、骨钙素和PTH-1受体转录本的表达，并消除CM/PDL细胞介导的体外矿化。这些结果表明，CM/PDL群体中的细胞是PTH和PTHrP作用的靶点，并且PTHrP可能在调节牙骨质的生物矿化中起重要作用。
