神经元素3蛋白(Ngn3)诱导大鼠骨髓间充质干细胞向胰岛素表达细胞分化的初步研究

Transdifferentiation of Rat Mesenchymal Stem Cells in vitro by Transduction of Ngn3 Protein

胰腺发育相关基因神经元素3(neurogenin3,Ngn3),属于碱性螺旋-环-螺旋(basic helix-loop-helix,bHLH)家族的转录因子,对胰腺内分泌细胞的发育及分化至关重要,且被认为是胰腺祖细胞的标志蛋白质.之前的研究发现,全长Ngn3蛋白具有蛋白质转导功能,可以高效进入多种真核细胞系.近年来多项研究显示,骨髓间充质干细胞是一种具有多向分化潜能的多能干细胞.利用蛋白质转导技术,将体外表达纯化的胰腺发育重要因子Ngn3蛋白导入体外分离培养的大鼠骨髓间充质干细胞中,诱导其向胰岛素表达细胞分化.结果显示,经Ngn3蛋白诱导的大鼠骨髓间充质干细胞出现细胞聚集生长现象,并有形状类似胰岛的细胞团出现.RT-PCR结果显示经Ngn3蛋白诱导的大鼠骨髓间充质干细胞可以有效表达胰岛素,并且一些β细胞相关基因如胰十二指肠同源盒基因-1(pancreatic-duodenal homeobox 1,Pdx-1),神经分化因子(neurogenic differentiation,NeuroD),同源结构域基因4(paired box gene 4,Pax4),葡萄糖转运体-2(glucose transporter 2,Glut-2)都有表达.细胞免疫荧光也可检测到胰岛素的表达.通过Ngn3蛋白质诱导分化大鼠骨髓间充质干细胞的初步研究,探索了应用骨髓间充质干细胞体外诱导分化获得胰岛素表达细胞的可行性,为糖尿病治疗提供一定的实验依据.

Neurogenin3 （Ngn3）, a basic helix-imp-helix transcription factor, plays a central role in endocrine pancreas differentiation and the development of pancreas. Our previous study has shown that Ngn3 protein has the ability to permeate cells. Recent reports have suggested bone marrow-derived mesenehymal stem ceils as a potential renewable source for pancreatic islet cells. The isolated rat mesenchymal stem cells（rMSCs） were treated with Ngn3 protein by protein transduction. After the treatment of Ngn3, they took morphologically changes which formed clusters like islet of Langerhans within one month and expressed insulin and several transcription factors, Pdx-1, NeuroD,Pax4 and Glut-2. Moreover, immonofluoresee confirmed the expression of insulin. The data suggest that Ngn3 protein transduction could be a novel strategy for the transdifferentiation of rat mesenchymal stem cells into insulin-expressing cells.