Wang Xiuli, Wang Wei, Ma Juan, Guo Xin, Yu Xingju, Ma Xiaojun
Laboratory of Biomedical Material Engineering, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China.
Biotechnol Prog. 2006 May-Jun;22(3):791-800. doi: 10.1021/bp050386n.
Embryonic stem (ES) cells hold promise either as an in vitro model recapitulating early embryonic development or as a renewable source of therapeutically useful cells. Certain aspects of the microenvironment (or niche) play critical roles in determining the fate of ES cells. Here, we reported the feasibility of using the technique of microencapsulation to study the interaction between ES cells and their tissue niche. ES cells' growth, viability, and differentiation in vitro were evaluated when they were enclosed in solid or liquefied core APA microcapsules. In comparison with those microcapsules with solid cores, the liquefied capsules provided a more suitable culture environment for the growth of ES cells. In addition, behavior of encapsulated ES cells in vivo was observed after their being implanted into mouse peritoneal cavities. In contrast to the prolonged lag phase in vitro, ES cells encapsulated grew much faster in vivo. Typical markers for the undifferentiated ES cells, such as AP, SSEA-1, and Oct-4 gene, were also tracked by immunochemistry and RT-PCR. Results showed that expression of markers remained high over 2 weeks of culture in vitro. However, decreased expression of markers was found in those samples in vivo with time passage. These findings implied that it was the combination of the intrinsic characteristics of ES cells and their microenvironment that regulated their fate. The APA-ES cells system may provide an optimal model to study the interaction between stem cells and their tissue niches.
胚胎干细胞有望成为概括早期胚胎发育的体外模型，或是成为治疗用细胞的可再生来源。微环境（或生态位）的某些方面在决定胚胎干细胞的命运中起着关键作用。在此，我们报告了使用微囊化技术研究胚胎干细胞与其组织生态位之间相互作用的可行性。当胚胎干细胞被包裹在实心或液化核心的APA微囊中时，对其体外生长、活力和分化进行了评估。与具有实心核心的微囊相比，液化微囊为胚胎干细胞的生长提供了更合适的培养环境。此外，将包裹的胚胎干细胞植入小鼠腹腔后，观察其在体内的行为。与体外延长的滞后期相反，包裹的胚胎干细胞在体内生长得更快。还通过免疫化学和逆转录-聚合酶链反应追踪未分化胚胎干细胞的典型标志物，如碱性磷酸酶（AP）、阶段特异性胚胎抗原-1（SSEA-1）和八聚体结合转录因子4（Oct-4）基因。结果表明，在体外培养2周以上，标志物的表达仍保持较高水平。然而，随着时间的推移，在体内样本中发现标志物的表达下降。这些发现表明，是胚胎干细胞的内在特性与其微环境的结合调节了它们的命运。APA-胚胎干细胞系统可能为研究干细胞与其组织生态位之间的相互作用提供一个最佳模型。
