Department of Anesthesiology, Shengjing Hospital, China Medical University, Shenyang, China.
Spine Research Institute, Longhua Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
J Cell Physiol. 2018 Oct;233(10):6921-6928. doi: 10.1002/jcp.26592. Epub 2018 Apr 25.
Notch activator Jagged1 (JAG1) plays a critical role in the regulation of osteoblast differentiation and bone metabolism. In this study, JAG1-induced osteoblast proliferation, differentiation, and mineralization has been analyzed in primary osteoblasts for up to 7 days. Alkaline phosphatase and Alizarin red staining showed an enhanced osteoblast maturation and mineralization in JAG1 treated cells, as well as higher mRNA levels of late osteoblast differentiation markers. In contrast, Notch inhibitor DAPT and deletion of Runx2 totally blocked JAG1 effects on osteoblast mineralization. Flow cytometry data further showed a significantly higher cell proliferation in early stages of culture at day 3, and lower levels of osteoblast apoptosis in late stages of culture at day 7. More importantly, activation of anti-apoptotic factor BCL-2 was enhanced, while pro-apoptotic factor Caspase3 was reduced in JAG1 treated osteoblasts. Therefore, we conclude that cell mineralization is enhanced via anti-apoptotic actions of Notch signaling within the osteoblast cells.
Notch 激活剂 Jagged1（JAG1）在调节成骨细胞分化和骨代谢中起着关键作用。在这项研究中，我们分析了 Jagged1 诱导的原代成骨细胞增殖、分化和矿化作用，时间长达 7 天。碱性磷酸酶和茜素红染色显示 Jagged1 处理的细胞中成骨细胞成熟和矿化增强，以及晚期成骨细胞分化标志物的 mRNA 水平更高。相比之下，Notch 抑制剂 DAPT 和 Runx2 的缺失完全阻断了 Jagged1 对成骨细胞矿化的作用。流式细胞术数据进一步显示，Jagged1 处理的细胞在培养第 3 天的早期阶段细胞增殖显著增加，而在培养第 7 天的晚期阶段成骨细胞凋亡水平降低。更重要的是，Jagged1 处理的成骨细胞中抗凋亡因子 BCL-2 的激活增强，而促凋亡因子 Caspase3 减少。因此，我们得出结论，Notch 信号在成骨细胞中通过抗凋亡作用增强细胞矿化。
