体内诱导小鼠诱导性多能干细胞向胸腺上皮细胞分化的方法

Generation of thymic epithelial cells in mouse by blastocyst injection of induced pluripotent stem cells

目的:探讨体内诱导小鼠诱导性多能干细胞(i PS)分化为胸腺上皮细胞的方法,为i PS细胞在再生医学中的应用奠定实验基础。方法:将表达绿色荧光蛋白的C57BL/6小鼠的i PS细胞,通过显微注射的方法,注射到ICR小鼠囊胚腔内,嵌合胚胎移植到代孕雌性小鼠子宫内,后代在出生后10 d左右通过毛色判定嵌合情况。将嵌合率50%以上的小鼠胸腺移植到BALB/c裸小鼠肾被膜下,4周后检测受体小鼠T淋巴细胞的重建情况。结果:受孕的代孕母鼠在胚胎移植后第17天左右自然分娩,共获得13只嵌合小鼠,嵌合体获得率为23.2%。从小鼠的被毛颜色评估,i PS来源的细胞在嵌合后代中所占的比例从5%到90%不等。嵌合体的胸腺表达绿色荧光蛋白,移植后在受体体内能促进受体T淋巴细胞重建。结论:通过构建嵌合体的体内诱导方法可获得i PS来源的有功能的胸腺上皮细胞。

Objective To examine an in vivo method for the differentiation of induced pluripotent stem cells （iPSCs） into thymic epithelial cells （TECs） in mice. Methods Green fluorescent protein-expressing iPS cells, derived from C57BL/6 mice, were injected into blastocysts from ICR mice. Chimeric blastocysts were then transferred into uteri of E2.5 pseudopregnant mice. Chimeric mouse could be identified by coat color 10 days after birth. The chimeric thymus was transplanted under the renal capsule of BALB/c nude mice. The spleen was cut out from the thymus-transplanted nude mice and the cells were dispersed and analyzed by a flow cytometer 4 weeks after transplantation. Results Chimeras were born 17 days after embryo transfer and 13 live-born chimeras were obtained. The contribution of iPSC-derived cells in the chimeras ranged from 5% to at most 90%. Typical thymic epithelium structure consisted of green fluorescent protein-expressing cells in chimera. The iPSCs-derived thymic epithelial cells could support the generation of new T cells. Conclusion The results indicate that mouse iPS cells can differentiate in vivo towards normally functioning TECs.