Duan Li, de Vos Paul, Fan Mingwen, Ren Yijin
Department of Orthodontics, University Medical Centre Groningen, University of Groningen, The Netherlands.
Front Biosci. 2008 May 1;13:7064-71. doi: 10.2741/3210.
The process of osteoclast differentiation and resorption is fine-tuned by signal pathways, which need to be further elucidated. The aim of this study was to explore the possible connections between NF-kappaB and Notch in RANKL-induced osteoclast activity. To this end, RANKL was used to stimulate mouse osteoclast precursor cell line RAW264.7. The number of multinucleated TRAP+ osteoclasts was counted and the resorption area was measured. NF-kappaB transcriptional factor activity was determined by EMSA. Quantitative RT-PCR and Western blotting analysis were used to determine Hes1 (one of Notch signaling primary targets) mRNA and protein expressions respectively. Mature osteoclasts and bone resorption areas were detected in the present study. NF-kappaB activity was increased in RANKL-induced osteoclast differentiation and resorption. mRNA and protein expressions of Hes1 in RAW264.7 cells were up-regulated after RANKL stimulation. In conclusion, NF-kappaB signaling mediated RANKL-induced osteoclast differentiation and resorption, during which, Notch signaling was activated. Therefore, Notch could be a novel therapeutic target for bone resorption related diseases.
破骨细胞的分化和吸收过程由信号通路进行精细调节，而这些信号通路仍有待进一步阐明。本研究的目的是探讨核因子-κB（NF-κB）与Notch信号通路在RANKL诱导的破骨细胞活性中的可能联系。为此，使用RANKL刺激小鼠破骨细胞前体细胞系RAW264.7。对多核抗酒石酸酸性磷酸酶阳性（TRAP+）破骨细胞的数量进行计数，并测量吸收面积。通过电泳迁移率变动分析（EMSA）测定NF-κB转录因子活性。分别使用定量逆转录聚合酶链反应（qRT-PCR）和蛋白质印迹分析来测定Hes1（Notch信号通路的主要靶点之一）的mRNA和蛋白质表达。本研究检测了成熟破骨细胞和骨吸收面积。在RANKL诱导的破骨细胞分化和吸收过程中，NF-κB活性增加。RANKL刺激后，RAW264.7细胞中Hes1的mRNA和蛋白质表达上调。总之，NF-κB信号通路介导了RANKL诱导的破骨细胞分化和吸收，在此过程中，Notch信号通路被激活。因此，Notch可能成为骨吸收相关疾病的新型治疗靶点。
