Yu Li-yun, Pei Yu, Xia Wei-bo, Xing Xiao-ping, Meng Xun-wu, Zhou Xue-ying
Department of Anesthesiology, Beijing Electric Power Hospital, Beijing 100073, China.
Chin Med J (Engl). 2007 Mar 20;120(6):491-5.
Fibroblast growth factor 9 (FGF9), expressed in brain, kidney and developing skeletal tissues, can physiologically inhibit endochondral ossification; but little is known about how FGF9 affects osteoblasts and its detailed regulatory mechanism. Here we examined the effect of FGF9 on the activity of the murine Runt-related transcription factor 2 (Runx2) gene promoter in preosteoblast MC3T3-E1 and premyoblast C2C12 cells.
Plasmids containing the Runx2 promoter region were transfected into MC3T3-E1 and C2C12 cells and stably transfected cell lines were established. The method of luciferase reporter gene activation was used to examine the effects of FGF9 on the promoter activity.
FGF9 (10 ng/ml) increased Runx2 promoter activity in MC3T3-E1 cells. When MC3T3-E1 cells were treated with FGF9 plus the various inhibitors or activator of the intracellular signaling transducation pathways, including 10 micromol/L U0126 (the inhibitor of mitogen-activated protein kinase kinase), 10 micromol/L SB203580 (the inhibitor of p38/mitogen activated protein kinase), or 1 micromol/L C6 ceramide (an activator of mitogen activated protein kinase), the luciferase expression did not change significantly compared with that of the cells treated with FGF9 only. However, when C2C12 cells were treated with 10 ng/ml FGF9, Runx2 gene promoter activity first decreased and then increased over a period of 1 to 5 days. Among the above inhibitors, only U0126 (10 micromol/L) completely blocked the effects of FGF9 on Runx2 gene promoter activity.
Our data showed that FGF9 can affect Runx2 gene promoter activity in MC3T3-E1 and C2C12 cells. The action of FGF9 appears to depend partly on the mitogen-activated protein kinase kinase/mitogen-activated protein kinase pathways in C2C12 cells.
成纤维细胞生长因子9（FGF9）在脑、肾和发育中的骨骼组织中表达，可在生理上抑制软骨内成骨；但关于FGF9如何影响成骨细胞及其详细调控机制知之甚少。在此，我们研究了FGF9对前成骨细胞MC3T3-E1和前成肌细胞C2C12中鼠类Runx相关转录因子2（Runx2）基因启动子活性的影响。
将含有Runx2启动子区域的质粒转染到MC3T3-E1和C2C12细胞中，并建立稳定转染的细胞系。采用荧光素酶报告基因激活方法检测FGF9对启动子活性的影响。
FGF9（10 ng/ml）增加了MC3T3-E1细胞中Runx2启动子活性。当MC3T3-E1细胞用FGF9加细胞内信号转导通路的各种抑制剂或激活剂处理时，包括10 μmol/L U0126（丝裂原活化蛋白激酶激酶抑制剂）、10 μmol/L SB203580（p38/丝裂原活化蛋白激酶抑制剂）或1 μmol/L C6神经酰胺（丝裂原活化蛋白激酶激活剂），与仅用FGF9处理的细胞相比，荧光素酶表达没有显著变化。然而，当C2C12细胞用10 ng/ml FGF9处理时，Runx2基因启动子活性在1至5天内先降低后升高。在上述抑制剂中，只有U0126（10 μmol/L）完全阻断了FGF9对Runx2基因启动子活性的影响。
我们的数据表明，FGF9可影响MC3T3-E1和C2C12细胞中Runx2基因启动子活性。FGF9的作用似乎部分取决于C2C12细胞中的丝裂原活化蛋白激酶激酶/丝裂原活化蛋白激酶通路。
