目的 探讨BMP和Notch信号通路介导红景天苷诱导骨髓间充质干细胞(MSCs)向神经细胞定向分化的分子机制。方法 实验分为对照组、红景天苷诱导组和阻断组。利用细胞免疫荧光化学方法、Real-Time PCR方法和Western blotting方法 分别研究了红景天苷对MSCs的增殖、形态以及对BMP和Notch信号通路的影响。结果 红景天苷影响MSCs的增殖且促进其形成神经元样细胞;细胞免疫荧光结果显示,红景天苷可降低Notch1和Jadge1阳性表达率(P<0.05);红景天苷诱导细胞12~72 h时,Notch1和Hes1 mRNA表达丰度明显下调(P<0.05);特异性阻断剂DAPT阻断Notch信号通路后,神经元细胞标志分子NSE、MAP-2和β-tubulin III mRNA和NSE、β-tubulin III蛋白的表达水平与阻断前比较显著上调(P<0.05)。12 h时Smad5和Smad8 mRNA的表达水平显著上调(P<0.01),且12和24 h时Smad1/5/8蛋白表达上调(P<0.05);Noggin阻断BMP信号通路后,NSE、MAP-2和β-tubulin III mRNA的表达丰度与诱导组比较明显下调(P<0.05);DAPT和Noggin同时阻断Notch和BMP信号通路后,与单独阻断BMP信号通路后比较,MAP-2和β-tubulin III mRNA的表达上调,NSE和β-tubulin III蛋白的表达水平上调(P<0.05)。结论 红景天苷通过抑制Notch信号通路、激活BMP信号通路诱导MSCs向神经元细胞定向分化。

Objective To study the molecule mechanism of salidroside inducing mesenchymal stem cells (MSCs) to directionally differentiate into neuronal cells via bone morphogenetic protein (BMP) and Notch signal pathways. Methods Experiments were divided into control, induced, and blocked groups. The technologies, such as immunofluorescence, real-time PCR, and Western blotting were used to analyze the effect of salidroside on cellular proliferation, morphosis, and BMP and Notch signal pathways. Results The immunofluorescence results showed that salidroside could affect cellular proliferation and induce MSCs to form the morphosis of neuronal cells. The positive rate of Notch1 and Jadge1 was significantly decrease to compare with the control (P < 0.05), real-time PCR results indicated that mRNA expression of Notch1 and Hes1 was obviously down-upregulated when treated with salidroside for 12-72 h (P < 0.05). However, Notch signal pathway was blocked with DAPT, a special inhibitor of Notch, the marker molecules of neuronal cells expression, such as neuron-specific enolase (NSE), microtubule associated protein 2 (MAP2), and β-tubulin III, were significantly increased when cells were treated with salisroside (P < 0.05). The mRNA levels of Smad5 and Smad8 were up-regulated when cells were treated with salidroside for 12 h, expression of Smad1/5/8 protein was increased at 12 and 24 h. When BMP signal pathway was blocked with Noggin, a special inhibitor of BMP, NSE, MAP2, and β-tubulin III mRNA expression was decreased to compare with the salidroside induced group (P < 0.05); When Notch and BMP signal pathways were simultaneously blocked with DAPT and Noggin, MAP2 and β-tubulin III mRNA expression was increased more obviously than that of the blocked with Noggin. Meanwhile the expression of NSE and β-tubulin III protein was also up-regulated (P < 0.05). Conclusion Salidroside promotes neuron-like differentiation of MSCs by negatively regulating the Notch pathway and activating BMP signal pathway, it plays a vital role for salidroside to inhibit Notch pathway on affecting MSCs differentiation.

国家自然科学基金面上项目资助(81073156)