Naturel两篇文章：更接近人类的小鼠胚胎干细胞培育成功

生物谷

    方兴未艾的干细胞研究领域又有新成果。来自英国和美国的两个独立研究小组6月27日分别在《自然》杂志在线发表论文指出，他们成功培养了一种名为EpiSC的新型小鼠胚胎干细胞。该种新型干细胞比现有的小鼠胚胎干细胞更接近人类，它的培养成功将有助于人们更好地理解人类细胞生长和分化的过程。

    领导这两个小组的分别是来自美国国立神经紊乱与中风研究所（U.S.  National  Institute  of  Neurological  Disorders  and  Stroke）的Ronald  McKay以及来自英国剑桥大学的Roger  Pedersen和Ludovic  Vallier，他们的实验对象分别是小鼠和大鼠。

    研究人员将受精卵植入小鼠子宫5天半后，就可从其外胚层分离得到EpiSC细胞。这是一种全新的多能性细胞，能够分化成各种组织。与传统的小鼠胚胎干细胞不同，该种细胞与人类的胚胎干细胞更为相似。比如，二者都需要关闭LIF（一种白血病抑制因子）以更好地分化，二者的基因表达和细胞表面标记的模式也基本相同。McKay认为，该种细胞代表了进化的更高级阶段，就好像是传统小鼠胚胎干细胞和已开始分化胚胎干细胞之间那条“丢失的链条”。他说：“绝大多数人都认为，将受精卵植入子宫后是无法分离出多能性细胞系的。”但是事实并非如此。

    至于大鼠的EpiSCs，Pedersen表示其与小鼠的很类似，并且预言科学家未来将能够从绝大多数甚至全部的哺乳动物胚胎内分离出这种细胞。他认为，从EpiSC分化出的细胞系有助于促进人类胚胎干细胞向组织的分化并用于疾病的治疗。

    来自斯坦福大学的干细胞学家Renee  Reijo  Pera乐观地认为，该种新型细胞的培养成功将有助于阐明人类胚胎干细胞的活动过程。她说，这项研究表明，科学家将有可能制造出具有专门应用目的的新型胚胎干细胞。（引自科学网）

原始出处:

文章（一）：

Nature advance online publication 27 June 2007 | doi:10.1038/nature05972; Received 30 April 2007; Accepted 31 May 2007; Published online 27 June 2007

New cell lines from mouse epiblast share defining features with human embryonic stem cells

Paul J. Tesar1,2,4, Josh G. Chenoweth1,4, Frances A. Brook2, Timothy J. Davies2, Edward P. Evans2, David L. Mack3, Richard L. Gardner2 & Ronald D. G. McKay1

Laboratory of Molecular Biology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
Mammalian Development Laboratory, Department of Zoology, University of Oxford, South Parks Road, Oxford OX1 3PS, UK
Stem Cell Biology Section, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA
These authors contributed equally to this work.

Correspondence to: Paul J. Tesar1,2,4Ronald D. G. McKay1 Correspondence and requests for materials should be addressed to R.D.G.M. (Email: mckayr@ninds.nih.gov) and P.J.T. (Email: paultesar@ninds.nih.gov).

Abstract
The application of human embryonic stem (ES) cells in medicine and biology has an inherent reliance on understanding the starting cell population. Human ES cells differ from mouse ES cells and the specific embryonic origin of both cell types is unclear. Previous work suggested that mouse ES cells could only be obtained from the embryo before implantation in the uterus1, 2, 3, 4, 5. Here we show that cell lines can be derived from the epiblast, a tissue of the post-implantation embryo that generates the embryo proper. These cells, which we refer to as EpiSCs (post-implantation epiblast-derived stem cells), express transcription factors known to regulate pluripotency, maintain their genomic integrity, and robustly differentiate into the major somatic cell types as well as primordial germ cells. The EpiSC lines are distinct from mouse ES cells in their epigenetic state and the signals controlling their differentiation. Furthermore, EpiSC and human ES cells share patterns of gene expression and signalling responses that normally function in the epiblast. These results show that epiblast cells can be maintained as stable cell lines and interrogated to understand how pluripotent cells generate distinct fates during early development.

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