骨保护素通过 syndecan-1 和磷酸肌醇 3-激酶/ Akt 诱导人牙周膜细胞骨桥蛋白的表达。

Osteoprotegerin induces osteopontin via syndecan-1 and phosphoinositol 3-kinase/Akt in human periodontal ligament cells.

机构信息

Department of Anatomy, Faculty of Dentistry, Chulalongkorn University, Patumwan, Bangkok, Thailand.

出版信息

J Periodontal Res. 2009 Dec;44(6):776-83. doi: 10.1111/j.1600-0765.2008.01190.x. Epub 2009 Jul 8.

DOI:10.1111/j.1600-0765.2008.01190.x

PMID:19602124

Abstract

BACKGROUND AND OBJECTIVE

Our previous study found that thrombin induced osteoprotegerin synthesis in human periodontal ligament cells. As elevated levels of osteoprotegerin can exert biological effects on various cell types, in the present study we investigated the effect of osteoprotegerin on the expression of osteopontin in human periodontal ligament cells.

MATERIAL AND METHODS

Cultured human periodontal ligament cells were treated with recombinant human osteoprotegerin (0-100 ng/mL) for 24-48 h. The expression of osteopontin mRNA and protein was analyzed using reverse transcription-polymerase chain reaction and western blot analyses, respectively. Phosphoinositol 3-kinase inhibitor, Akt inhibitor, heparinase, neutralizing antibody against receptor activator of nuclear factor-kappaB ligand (RANKL) and syndecan-1, and small interfering RNA against syndecan-1, were used to determine the mechanism involved.

RESULTS

Osteoprotegerin up-regulated the mRNA and protein expression of osteopontin in human periodontal ligament cells in a dose-dependent manner. Addition of neutralizing antibody against RANKL attenuated the inductive effect of osteoprotegerin on osteopontin expression. In addition, the inductive effect of osteoprotegerin was abolished by phosphoinositol 3-kinase and Akt inhibitors, as well as by syndecan-1 antibody or syndecan-1 small interfering RNA. None of the inhibitors had any effect on the background level of osteopontin expression.

CONCLUSION

An increased level of osteoprotegerin can generate signals via a RANKL/syndecan-1/phosphoinositol 3-kinase/Akt pathway. The results also suggest that osteopontin is one of the downstream targets of the pathway mediated by osteoprotegerin in human periodontal ligament cells. Thus, in addition to counteracting RANKL in the RANKL-osteoprotegerin system, osteoprotegerin may play a role in periodontal tissue remodeling through modulation of the extracellular matrix.

摘要

背景与目的

我们之前的研究发现凝血酶可诱导人牙周膜细胞合成护骨素。由于护骨素水平的升高可以对各种细胞类型发挥生物学效应，因此在本研究中，我们研究了护骨素对人牙周膜细胞中骨桥蛋白表达的影响。

材料与方法

用重组人护骨素（0-100ng/ml）处理培养的人牙周膜细胞 24-48h。分别采用逆转录-聚合酶链反应和 Western blot 分析检测骨桥蛋白 mRNA 和蛋白的表达。使用磷酸肌醇 3-激酶抑制剂、Akt 抑制剂、肝素酶、核因子-κB 配体（RANKL）受体拮抗剂中和抗体和 syndecan-1 小干扰 RNA 来确定涉及的机制。

结果

护骨素呈剂量依赖性地上调人牙周膜细胞中骨桥蛋白的 mRNA 和蛋白表达。添加 RANKL 受体拮抗剂中和抗体可减弱护骨素对骨桥蛋白表达的诱导作用。此外，磷酸肌醇 3-激酶和 Akt 抑制剂以及 syndecan-1 抗体或 syndecan-1 小干扰 RNA 均可消除护骨素的诱导作用。这些抑制剂对骨桥蛋白的背景表达均无影响。