Induction of dopaminergic neurons from human ES cells, and transplantation of the cells into monkey Parkinson's disease models

我们从日本京都大学建立的人类胚胎干细胞系KhES-1、-2 -3中诱导多巴胺能神经元，将人类胚胎干细胞衍生的神经祖细胞移植到猴帕金森病的纹状体中，其中一只猴子出现肿瘤形成。PET扫描显示肿瘤区域葡萄糖代谢和氟噻咪啶摄取增加。免疫荧光研究显示肿瘤中有Oct3/4-、ES细胞标记阳性细胞聚集。在对移植细胞的分析中发现，导致肿瘤形成的细胞中含有oct3 /4阳性的ES细胞，而未形成肿瘤的细胞中不含这种细胞。这些结果表明移植物中受污染的胚胎干细胞导致肿瘤形成。利用小鼠胚胎干细胞证实了这种可能性。当选择胚胎干细胞衍生的神经祖细胞（npc）时。通过荧光活化细胞分选（FACS），这些细胞从未在小鼠脑或免疫缺陷小鼠皮下间隙发现任何肿瘤。这些结果表明，NPCs的纯化对于安全有效的细胞移植至关重要，目前我们正在开发人类胚胎干细胞来源的NPCs的筛选方法。

We induced dopaminergic neurons from human ES cell lines, KhES-1, -2 -3, which were established in Kyoto University, Japan-When we grafted human ES cell-derived neural progenitors into the striatum of monkey Parkinson's disease, one of the three monkeys showed tumor formation. PET scan demonstrated an increase of glucose metabolism and an uptake of fluorothimidine at the tumor region. Immunofluorescence study showed accumulation of Oct3/4-, ES cell marker positive cells in the tumor. In to analysis of the grafted cells revealed that the cells which caused tumor formation contained Oct3/4-positive ES cells, but that the cells which did not tumors contained no such cells. These results suggest that contaminated ES cells in the graft lead to tumor formation.This possibility was confirmed by using mouse ES cells. When ES cell-derived neural progenitor cells (NPCs) were selected. by fluorescence-activated cell sorting (FACS), these cells never famed any tumors in the mouse brain or subcutaneous space of immunodeficient mice.These results indicate that purification of NPCs is important for the safe and effective cell transplantation, and we are now developing the method to sort out human ES cell-derived NPCs.