Application of nuclear transferred embryonic stem cells for reconstitution of hematopoiesis

人类胚胎干细胞（ES）细胞系的建立促进了对这些细胞潜在应用的研究。胚胎干细胞衍生细胞群用于细胞治疗似乎是更有前途的临床应用之一。然而，有一些理由限制胚胎干细胞衍生细胞的临床应用。一种情况是胚胎干细胞和受体细胞之间的主要组织相容性（MHC）抗原不匹配。这一限制可以通过几种方式克服：使用胚胎干细胞衍生的抗原呈递细胞诱导受体耐受；产生多种ES细胞系，覆盖多种MHC类型；生产具有来自受体细胞核的克隆胚胎干细胞系，即所谓的“治疗性克隆”。利用小鼠卵母细胞和细胞核建立核转移ES细胞系是可行的。另一方面，虽然人类ntES细胞系的建立尚未成功，但更有可能的是，未来建立人类ntES细胞系的技术将得到发展。在临床使用人类ntES细胞系之前，许多基础研究应该使用小鼠和/或灵长类动物ntES细胞系进行。由于许多研究小组已经报道了造血细胞可以从人类胚胎干细胞中提取，因此造血细胞也可能从人类胚胎干细胞中提取。然后，我们测试了是否可以从小鼠ntES细胞中获得造血细胞。首先，我们分析了几种小鼠ntES细胞系的特征。所有经测试的小鼠ntES细胞系均具有与普通胚胎干细胞细胞系非常相似的特征，如形态学、细胞表面表型和基因表达模式。接下来，我们测试了小鼠ntES细胞在诱导这些细胞成为造血细胞后是否能够产生造血细胞。结果表明，所有小鼠ntES细胞系均能产生强大的造血细胞。我们目前正在研究造血干细胞是否包含在小鼠ntES细胞产生的造血细胞群中。此外，我们将通过移植试验来测试这些造血干细胞在体内能否重建造血细胞的潜力。少

The establishment of a number of human embryonic stem (ES) cell lines has spurred research into the potential applications of such cells. The use of ES cell-derived cell populations for cell therapy appears to be one of the more promising clinical applications. However, there are a few reasons to limit clinical uses of the cells derived from ES cells. One is in the case of a mismatch of major histo-compatibility (MHC) antigen between the ES cells and the recipient's cells. This limitation may be overcome in several ways: an induction of tolerance in the recipient using ES cell-derived antigen-presenting cells; production of many ES cell lines to cover many types of MHC; production of cloned ES cell lines that possess nuclei derived from the recipient, i.e. so called "therapeutic cloning".The establishment of nuclear transferred ES (ntES) cell line is possible with mouse oocytes and nuclei. On the other hand, although the establishment of human ntES cell line has not been succeeded yet, … More it is highly likely that the technology to establish human ntES cell line will be developed in the future. Prior to the use of human ntES cell lines in the clinic, many basic researches should be performed using mouse and/or primate ntES cell lines.Since many groups have already reported that hematopoietic cells can be derived from human ES cells, hematopoietic cells may be also derived from human ntES cells. Then, we have tested whether hematopoietic cells can be derived from mouse ntES cells. First, we have analyzed the characteristics of several mouse ntES cell lines. All mouse ntES cell lines tested have demonstrated that they have the characteristics quite similar to ordinary ES cell lines, e.g., in morphology, cell surface phenotype, and gene expression pattern. Next, we have tested whether mouse ntES cells could produce hematopoietic cells following the induction of those cells into hematopoietic cells. As the results, all mouse ntES cell lines tested could produce hematopoietic cells robustly.We are currently studying whether hematopoietic stem cells are included in the hematopoietic cell population produced from mouse ntES cells. In addition, we will test the potential of those hematopoietic stem cells whether they can reconstitute hematopoietic cells in vivo by transplantation assay. Less