Effect of Lipopolysaccharide on alveolar bone metabolism

脂多糖对牙槽骨代谢的影响

• 批准号: 05671605
• 负责人: SHIMOJIMA Takahiro
• 金额: $ 1.15万
• 依托单位: Meikai University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1993
• 资助国家: 日本
• 起止时间: 1993 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05671605/
• 关键词: lipopolysaccharide; osteoblast; osteoclast formation; GM-CSF; IL-6; リポ多糖体; 破骨細胞

We recentily found that LPS stimulates osteoclast formation by IL-1 production on its precursor cell in long-term human cord blood cultures. This suggests that the mechanisms of osteoclast formation on LPS might removed by disaggregation from the influence of some cell typy, present in intact bone, that mediates cytokine resposiveness. We therefore tested the ability of cloned osteoblastic cell derived from human osteosalcoma (MG63) and osteoblastic cells derived from human alveolar bone restore hormone and cytokine responsiveness to unresponsive populations of osteoclast precursors. We found that conditioned medium (CM) from LPS (100ng/ml) -treated MG63 cell cultures induced a two-fold stimulation of osteoclast formation from human hemopoietic stem cells. Stimulation was observed at dilution of 33% (v/v) concentration of CM in the medium. The effects of LPS onthe regulation of IL-6, macrophage-colony stimulating factor (M-CSF), and granulocyte macrophage-colony stimulating factor (GM-CSF) gene expression were also studied in MG63 cells. GM-CSF,IL-6, and M-CSF transcripts were detectable in LPS-treated MG63 cells. However, GM-CSF gene expression did not occur in PTH or non stimulated osteoblast cultures. When CD34-positive hemopoietic cells were incubated with CM from LPS-treated osteoblasts, CFU-GM colonies which contain osteoclast early precursors were formed. This finding is proof that GM-CSF was present in the cell-free CM that stimulated osteoclast formation. Furthermore demonstrate in situ hybridization studies could be performed to have GM-CSF mRNA in LPS-treated osteoblasts from normal human bone. These experiments suggest that LPS stimulates osteoclast formation through a primary action on osteoblastic cells, which cells are induced by the LPS to produce IL-6, M-CSF,and GM-CSF which in turn stimulate osteoclast formation, resulting in osteoclastic bone resorption.

我们最近发现，在长期培养的人脐血中，内毒素通过在其前体细胞上产生IL-1来刺激破骨细胞的形成。这表明，破骨细胞在脂多糖上形成的机制可能通过解聚某些细胞类型的影响而消除，这些细胞类型存在于完整的骨骼中，介导细胞因子的反应。因此，我们测试了克隆的人骨肉瘤成骨细胞(MG63)和人牙槽骨修复激素来源的成骨细胞对破骨细胞前体无反应群体的细胞因子反应能力。我们发现，经内毒素(100 ng/ml)处理的MG63细胞的条件培养液(CM)对人造血干细胞的破骨细胞形成有两倍的刺激作用。当培养液中CM浓度为33%(v/v)时，可观察到刺激作用。研究了内毒素对MG63细胞IL-6、巨噬细胞集落刺激因子(M-CSF)和粒细胞巨噬细胞集落刺激因子(GM-CSF)基因表达的调节作用。在脂多糖处理的MG63细胞中可检测到GM-CSF、IL-6和M-CSF的转录本。然而，在甲状旁腺激素或非刺激的成骨细胞培养中，GM-CSF基因没有表达。当CD34阳性的造血细胞与脂多糖处理的成骨细胞的CM孵育时，形成了含有破骨细胞早期前体的CFU-GM集落。这一发现证明GM-CSF存在于刺激破骨细胞形成的无细胞CM中。进一步证明，在脂多糖处理的人正常骨成骨细胞中可以进行GM-CSF mRNA的原位杂交研究。这些实验表明，内毒素通过对成骨细胞的初级作用刺激破骨细胞的形成，成骨细胞在内毒素的诱导下产生IL-6、M-CSF和GM-CSF，继而刺激破骨细胞的形成，导致破骨细胞性骨吸收。