Establishment of Culture System Capable of Inducing Neural Crest Cells from ES Cells

小鼠胚胎干细胞（embryonic stem cells，ES细胞）是从3、5天囊胚内细胞团中分离出来的全能性、原始性、外胚层样细胞。作为黑素细胞分化的体外模型，我们建立了从全能ES细胞系诱导黑素细胞的培养体系。当未分化的ES细胞与骨髓来源的基质细胞系共培养时，可重复地产生非常小但显著数量的黑素细胞。这一过程通过向培养物中添加地塞米松而大大增强，并且严格依赖于c-Kit信号传导和内皮素3信号传导。在这项研究中，我们发现尾化因子视黄酸提高了黑素细胞诱导的效率在这种文化。黑素细胞的早期前体细胞，在几个通道后克隆增殖，有效地诱导在培养和他们的自我更新刺激的内皮素3的加入，也由视黄酸。这些结果表明，神经嵴细胞在该培养系统中诱导相应的体内发育。

Mouse embryonic stem (ES) cells are totipotent, primitive, ectodermal-like cells derived from inner cell mass of 3,5 day blastocysts. As an in vitro model for melanocyte differentiation, we have developed the culture system to induce melanocytes from totipotent ES cell line. When undifferentiated ES cells were co-cultured with a bone marrow-derived stromal cell line, a very small but significant number of melanocytes were reproducibly generated. This process was greatly enhanced by addition of dexamethasone to the culture and strictly depended on the c-Kit signaling and endothelin 3 signaling. In this study, we found that caudalizing factor retinoic acid enhanced the efficiency of melanocyte induction in this culture. The early precursors for melanocytes, which proliferate clonally after several passages, were efficiently induced in the culture and their self-renew was stimulated by the addition of endothelin 3 and also by retinoic acid. These results suggests that neural crest cells are induced in this culture system upon corresponding in vivo development.