| 1 | Cell signalling pathways underlying induced pluripotent stem cell reprogramming显示文摘Induced pluripotent stem(i PS) cells, somatic cells reprogrammed to the pluripotent state by forced expression of defined factors, represent a uniquely valuable resource for research and regenerative medicine. However, this methodology remains inefficient due to incomplete mechanistic understanding of the reprogramming process. In recent years, various groups have endeavoured to interrogate the cell signalling that governs the reprogramming process, including LIF/STAT3, BMP, PI3 K, FGF2, Wnt, TGFβ and MAPK pathways, with the aim of increasing our understanding and identifying new mechanisms of improving safety, reproducibility and efficiency. This has led to a unified model of reprogramming that consists of 3 stages: initiation, maturation and stabilisation. Initiation of reprogramming occurs in almost all cells that receive the reprogramming transgenes; most commonly Oct4, Sox2, Klf4 and c Myc, and involves a phenotypic mesenchymal-to-epithelial transition. The initiation stage is also characterised by increased proliferation and a metabolic switch from oxidative phosphorylation to glycolysis. The maturation stage is considered the major bottleneck within the process, resulting in very few 'stabilisation competent' cells progressing to the final stabilisation phase. To reach this stage in both mouse and human cells, pre-i PS cells must activate endogenous expression of the core circuitry of pluripotency, comprising Oct4, Sox2, and Nanog, and thus reach a state of transgene independence. By the stabilisation stage, i PS cells generally use the same signalling networks that govern pluripotency in embryonic stem cells. These pathways differ between mouse and human cells although recent work has demonstrated that this is context dependent. As i PS cell generation technologies move forward, tools are being developed to interrogate the process in more detail, thus allowing a greater understanding of this intriguing biological phenomenon. | Kate Hawkins Shona Joy Tristan Mc Kay | 2014 | World Journal of Stem Cells2014，6，5： | 5 |
| 2 | 牛囊胚ICM克隆多能性标记基因与表面标记的研究显示文摘本研究旨在探究牛类胚胎干细胞(Embryonic stem cells,ES)的多能性标记基因与表面标记,为优化牛类ES细胞培养条件和相关研究提供依据。利用2i/LIF培养液,通过全胚接种及机械传代法分离培养牛囊胚内细胞团(Inner cell mass,ICM),免疫荧光染色法检测其多能性标记基因与表面标记;qRT-PCR检测免疫磁珠法分选的牛囊胚ICM和滋养层细胞(Trophectoderm cell,TE)的多能性标记基因的差异表达结果。试验成功分离出了牛囊胚ICM克隆,并体外培养至第10代,且各代克隆均呈现出了典型的干细胞形态。结果表明,ICM表面标记SSEA1、SSEA4和TRA-1-60染色为阳性,且多能性标记基因OCT4、SOX2和NANOG在其中均有表达;OCT4、SOX2和NANOG在牛囊胚ICM和TE中的表达存在差异(P<0.05),其中SOX2的差异极显著(P<0.01)。综上表明,2i/LIF培养液有助于牛囊胚ICM的培养;SOX2可能成为牛ICM克隆的候选多能性标记基因。 | 崔莉莎 赵学明 郝海生 杜卫华 马友记 朱化彬 王宗礼 | 2015 | 畜牧兽医学报2015，46，7： | 1 |
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