3月22日，国际学术期刊Cell Research在线发表了中科院上海生命科学研究院/上海交大医学院健康所、中科院干细胞生物学重点实验室杨黄恬研究组和上海生命科学研究院生化与细胞所肖磊研究组合作的最新研究成果。本项研究建立了全新的大鼠胚胎干细胞（rat embryonic stem cells, rESCs）体外分化体系，并在国际上率先证实rESCs可以在体外分化为具有功能性的心肌细胞。
大鼠是最早被用于科学研究的实验动物。与最为常用的模式生物小鼠相比，大鼠具有许多独特的优势，如生理特征与药物反应性与人更为接近等，因而长期广泛地应用于行为学、生理学和药理学以及毒性测试等实验。大鼠疾病模型也已成功应用于心脏衰竭，高血压，糖尿病，神经性疾病等的研究。然而由于缺乏类似于小鼠的胚胎干细胞系，大鼠在实验研究中的应用受到了极大地限制。2008年，Austin Smith和Qi-long Ying研究组通过应用特殊的无血清培养系统，成功建立了真正的具有多能性的rESCs。然而，目前rESCs体外分化仍非常困难。
杨黄恬研究员的博士研究生曹楠在肖磊研究组廖婧博士建立的rESCs系基础上，通过系统的筛选和摸索，结合使用条件性培养基以及特定的信号通路抑制剂，建立了可同时分化至内、中、外三胚层的rESCs体外分化模型，并成功获得了具有典型大鼠胚胎心肌细胞形态和肌丝结构特征的心肌细胞，该分化系统时序表达中胚层、心肌前体细胞和心肌细胞的标志性基因，分化的细胞包括了三种主要的心肌细胞类型：心室肌细胞、心房肌细胞以及窦房结细胞，且分化的心肌细胞对b-肾上腺素受体激动剂Isoproterenol和乙酰胆碱激动剂Carbachol也显现与大鼠胚胎心肌细胞类似的反应。
该项研究建立的rESCs体外分化模型为研究心脏发生、发育的分子机制、心肌细胞药物毒性检测和促进心肌细胞分化、改善心肌细胞收缩和心电功能的化合物筛选提供了新的工具，也为进一步开展细胞治疗研究提供了新途径。
该项研究工作得到了国家科技部、农业部、国家自然科学基金委和中国科学院的支持。（生物谷Bioon.com）
生物谷推荐原文出处：
Cell Research , (22 March 2011) | doi:10.1038/cr.2011.48
In vitro differentiation of rat embryonic stem cells into functional cardiomyocytes
Nan Cao, Jing Liao, Zumei Liu, Wenmin Zhu, Jia Wang, Lijun Liu, Lili Yu, Ping Xu, Chun Cui, Lei Xiao and Huang-Tian Yang
AbstractThe recent breakthrough in the generation of rat embryonic stem cells (rESCs) opens the door to application of gene targeting to create models for the study of human diseases. In addition, the in vitro differentiation system from rESCs into derivatives of three germ layers will serve as a powerful tool and resource for the investigation of mammalian development, cell function, tissue repair, and drug discovery. However, these uses have been limited by the difficulty of in vitro differentiation. The aims of this study were to establish an in vitro differentiation system from rESCs and to investigate whether rESCs are capable of forming terminal-differentiated cardiomyocytes. Using newly established rESCs, we found that embryoid body (EB)-based method used in mouse ESC (mESC) differentiation failed to work for the serum-free cultivated rESCs. We then developed a protocol by combination of three chemical inhibitors and feeder-conditioned medium. Under this condition, rESCs formed EBs, propagated and differentiated into three embryonic germ layers. Moreover, rESC-formed EBs could differentiate into spontaneously beating cardiomyocytes after plating. Analyses of molecular, structural, and functional properties revealed that rESC-derived cardiomyocytes were similar to those derived from fetal rat hearts and mESCs. In conclusion, we successfully developed an in vitro differentiation system for rESCs through which functional myocytes were generated and displayed phenotypes of rat fetal cardiomyocytes. This unique cellular system will provide a new approach to study the early development and cardiac function, and serve as an important tool in pharmacological testing and cell therapy.
