文章摘要
徐巧明,凡 进,周 炜,蔡卫华,张 宁,殷国勇.GIT1通过BMP-2/p-Smad1/5/8信号通路调节骨折愈合[J].南京医科大学学报,2015,(10):1355~1359
GIT1通过BMP-2/p-Smad1/5/8信号通路调节骨折愈合
The mechanism of fracture healing regulated by GIT1 though BMP-2 p-Smad1/5/8 signal pathway
投稿时间:2015-03-09  
DOI:10.7655/NYDXBNS20151004
中文关键词: G蛋白偶联受体激酶结合蛋白1  骨形态发生蛋白2  骨折愈合  软骨内骨化
英文关键词: G-protein coupled reaptor kinase-interacting protein 1  bone morphogenetic protein 2  fracture healing  endochondral ossification
基金项目:国家自然科学基金资助(81271988)
作者单位
徐巧明 1南京医科大学第一附属医院骨科,江苏 南京 210029
2昆山市第六人民医院骨科,江苏 昆山 215300 
凡 进 南京医科大学第一附属医院骨科,江苏 南京 210029 
周 炜 南京医科大学第一附属医院骨科,江苏 南京 210029 
蔡卫华 南京医科大学第一附属医院骨科,江苏 南京 210029 
张 宁 南京医科大学第一附属医院骨科,江苏 南京 210029 
殷国勇 南京医科大学第一附属医院骨科,江苏 南京 210029 
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中文摘要:
      目的:探讨G蛋白偶联受体激酶结合蛋白1(G-protein coupled receptor kinase-interacting protein 1,GIT1)影响骨折愈合的具体机制。方法:分别取 GIT1基因敲除小鼠和同窝野生型小鼠制作股骨骨折模型,每组30只。造模成功后2周,免疫组化检测骨痂区软骨细胞矿化及p-Smad1/5/8表达量。分别取2组小鼠的骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSCs),予以10 ng/mL的骨形态发生蛋白2(bone morphogenetic protein 2,BMP2)刺激后检测Smad1/5/8磷酸化水平和核转入能力;取C3H10T1/2细胞,分别用1 μg pGL3重组质粒和1 μg GIT1-siRNA共转染细胞,荧光报告素酶技术检测细胞内GIT1蛋白对BMP2转录水平的影响。结果:与同窝野生型小鼠相比,GIT1基因敲除小鼠软骨内骨化减弱,骨痂区软骨细胞堆积,骨折愈合延迟,p-Samd1/5/8表达水平明显减少;与GIT1基因敲除小鼠相比,BMP2可明显提高同窝野生型小鼠BMCs中p-Samd1/5/8核转入能力;GIT1蛋白表达的缺失可明显降低BMP2的转录水平。结论:GIT1可通过调节Samd1/5/8的磷酸化及BMP2信号转导影响骨折部位的软骨内骨化。
英文摘要:
      Objective:To study the role of G-protein coupled receptor kinase-interacting protein 1 (GIT1) in fracture healing. Methods: GIT1 knockout(KO) mice (n=30) and GIT1 wildtype(WT) mice (n=30) were used to established the femoral model according to our pervious study. Immunohistochemical (IHC) staining was used to detect the endochondral mineralization and the expression of Smad1/5/8 in callus area. Bone marrow mesenchymal stem cells (BMSCs) of GIT1 WT and KO mice were collected and stimulated with 10 ng/mL BMP2,and then the expression of p-Smad1/5/8 and the level of p-Smad1/5/8 translocated into the nuclei of BMSCs were detected. One μg of GIT1-siRNA (or control-siRNA) was co-transfected into C3H10T1/2 cells. Luciferase reporter genes was used to detecte the influence of GIT1 on BMP2 transcription. Results:GIT1 KO mice exhibited delayed fracture healing,chondrocyte accumulation in the fracture area,and reduced staining intensity of phosphorylated Smad1/5/8 (p-Smad1/5/8). BMSCs extracted from GIT1 KO mice showed a decline of p-Smad1/5/8 levels and of p-Smad1/5/8 translocated into the cell nucleus after BMP2 stimulus. The results of luciferase reporter gene assay showed that the level of intracellular GIT1 protein significantly affected the level of BMP2 transcription through p-Smad1/5/8. Conclusion: GIT1 regulates Smad1/5/8 phosphorylation and mediates BMP2 regulation,thus affecting endochondral ossification.
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