Serine dipeptide lipids of Porphyromonas gingivalis inhibit osteoblast differentiation: Relationship to Toll-like receptor 2.
Serine dipeptide lipids of Porphyromonas gingivalis inhibit osteoblast differentiation: Relationship to Toll-like receptor 2.
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DOI：
10.1016/j.bone.2015.09.008
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发表时间：
2015-12
期刊：
影响因子：
4.1
通讯作者：
Nichols FC
中科院分区：
文献类型：
--
作者：
Wang YH;Nemati R;Anstadt E;Liu Y;Son Y;Zhu Q;Yao X;Clark RB;Rowe DW;Nichols FC
牙龈卟啉单胞菌是一种牙周病原体，与牙齿附着和支撑骨的丧失密切相关。我们之前已经证明，牙龈卟啉单胞菌的总脂质提取物通过与 Toll 样受体 2 (TLR2) 的结合来抑制成骨细胞分化，并且牙龈卟啉单胞菌的丝氨酸二肽脂质与小鼠和人的 TLR2 结合。本研究的目的是确定这些丝氨酸脂质是否在体外和体内抑制成骨细胞分化以及是否涉及 TLR2 参与。成骨细胞取自也表达 Col2.3GFP 转基因的野生型或 TLR2 敲除小鼠幼崽的颅骨。测试了两类丝氨酸二肽脂质，称为脂质 654 和脂质 430。通过细胞 GFP 荧光和成骨细胞基因表达监测成骨细胞分化，并通过 von Kossa 染色矿物质沉积物监测成骨细胞功能。在维持 21 天的颅骨细胞培养物中评估成骨细胞的分化和功能。 Lipid 654 显着抑制 GFP 表达、成骨细胞基因表达和矿物质结节形成，并且这种抑制依赖于 TLR2 的参与。 Lipid 430 还显着抑制 GFP 表达、成骨细胞基因表达和矿物质结节形成，但这些效应仅部分归因于 TLR2 的参与。更重要的是，Lipid 430 刺激野生型细胞中的 TNF-α 和 RANKL 基因表达，但不刺激 TLR2 敲除细胞中的 TNF-α 和 RANKL 基因表达。最后，观察到成骨细胞培养物将脂质 654 水解为脂质 430，这可能是通过培养细胞中 PLA2 活性升高而发生的。总之，我们的结果表明牙龈卟啉单胞菌的丝氨酸二肽脂质至少部分通过TLR2的参与抑制成骨细胞分化和功能。 Lipid 430 丝氨酸类还增加了可增加破骨细胞活性的基因的表达。我们得出结论，脂质 654 和脂质 430 有可能促进 TLR2 依赖性骨丢失，正如口腔感染牙龈卟啉单胞菌后实验性牙周炎所报道的那样。这些结果也支持丝氨酸二肽脂质参与慢性牙周炎的牙槽骨丢失的结论。
Porphyromonas gingivalis is a periodontal pathogen strongly associated with loss of attachment and supporting bone for teeth. We have previously shown that the total lipid extract of P. gingivalis inhibits osteoblast differentiation through engagement of Toll-like receptor 2 (TLR2) and that serine dipeptide lipids of P. gingivalis engage both mouse and human TLR2. The purpose of the present investigation was to determine whether these serine lipids inhibit osteoblast differentiation in vitro and in vivo and whether TLR2 engagement is involved. Osteoblasts were obtained from calvaria of wild type or TLR2 knockout mouse pups that also express the Col2.3GFP transgene. Two classes of serine dipeptide lipids, termed Lipid 654 and Lipid 430, were tested. Osteoblast differentiation was monitored by cell GFP fluorescence and osteoblast gene expression and osteoblast function was monitored as von Kossa stained mineral deposits. Osteoblast differentiation and function were evaluated in calvarial cell cultures maintained for 21 days. Lipid 654 significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation and this inhibition was dependent on TLR2 engagement. Lipid 430 also significantly inhibited GFP expression, osteoblast gene expression and mineral nodule formation but these effects were only partially attributed to engagement of TLR2. More importantly, Lipid 430 stimulated TNF-α and RANKL gene expression in wild type cells but not in TLR2 knockout cells. Finally, osteoblast cultures were observed to hydrolyze Lipid 654 to Lipid 430 and this likely occurs through elevated PLA2 activity in the cultured cells. In conclusion, our results show that serine dipeptide lipids of P. gingivalis inhibit osteoblast differentiation and function at least in part through engagement of TLR2. The Lipid 430 serine class also increased the expression of genes that could increase osteoclast activity. We conclude that Lipid 654 and Lipid 430 have the potential to promote TLR2-dependent bone loss as is reported in experimental periodontitis following oral infection with P. gingivalis. These results also support the conclusion that serine dipeptide lipids are involved in alveolar bone loss in chronic periodontitis.