Department of Periodontology, School of Dentistry, Shandong University, Jinan, China.
Cell Prolif. 2011 Oct;44(5):420-7. doi: 10.1111/j.1365-2184.2011.00769.x.
To investigate tumor necrosis factor alpha (TNF-α)-induced changes in osteogenic differentiation from mesenchymal stem cells (MSCs).
Blockade of nuclear factor-κB (NF-κB) was achieved in ST2 murine MSCs via overexpression of the NF-κB inhibitor, IκBα. Osteogenic differentiation was induced in IκBα-overexpressing ST2 cells and normal ST2 cells when these cells were treated with TNF-α at various concentrations. Expression levels of bone marker genes were determined using real time RT-PCR and ALP activity assay. In vitro mineralization was performed to determine long-term exposure to TNF-α on mineral nodule formation. MTT assay was used to determine the changes in cell proliferation/survival.
Levels of Runx2, Osx, OC and ALP were up-regulated in cell cultures treated with TNF-α at lower concentrations, while down-regulated in cell cultures treated with TNF-α at higher concentrations. Blockade of NF-κB signaling reversed the inhibitory effect observed in cell cultures treated with TNF-α at higher concentrations, but showed no effect on cell cultures treated with TNF-α at lower concentrations. In contrast, long-term treatment of TNF-α at all concentrations induced inhibitory effects on in vitro mineral nodule formation. MTT assay showed that TNF-α inhibits proliferation/survival of mesenchymal stem cells when the NF-κB signaling pathway is blocked.
The binding of TNF-α to its receptors results in the activation of multiple signaling pathways, which actively interact with each other to regulate the differentiation, proliferation, survival and apoptosis of MSCs.
研究肿瘤坏死因子-α（TNF-α）诱导间充质干细胞（MSCs）成骨分化的变化。
通过过表达 NF-κB 抑制剂 IκBα，在 ST2 鼠 MSC 中阻断核因子-κB（NF-κB）。在 TNF-α以不同浓度处理 IκBα过表达的 ST2 细胞和正常 ST2 细胞时，诱导成骨分化。采用实时 RT-PCR 和碱性磷酸酶（ALP）活性测定法测定骨标记基因的表达水平。进行体外矿化实验以确定 TNF-α对长期矿化结节形成的影响。MTT 法测定细胞增殖/存活的变化。
较低浓度 TNF-α处理的细胞培养物中 Runx2、Osx、OC 和 ALP 水平上调，而较高浓度 TNF-α处理的细胞培养物中下调。NF-κB 信号通路的阻断逆转了高浓度 TNF-α处理的细胞培养物中观察到的抑制作用，但对低浓度 TNF-α处理的细胞培养物没有影响。相反，所有浓度的 TNF-α长期处理均对体外矿化结节形成产生抑制作用。MTT 实验表明，当 NF-κB 信号通路被阻断时，TNF-α抑制间充质干细胞的增殖/存活。
TNF-α与其受体结合导致多种信号通路的激活，这些信号通路相互积极作用，调节 MSC 的分化、增殖、存活和凋亡。
