近日,刊登在国际杂志Proceedings of the National Academy of Sciences上的一篇研究论文中,来自日本理化研究所的研究人员通过研究成功诱导人类胚胎干细胞(ES),将其转化成为大脑皮层组织。
此前研究者开发了一种新型的细胞培养技术,其可以使得ES细胞悬浮其中,从而使得这些ES细胞自组装形成复杂的三维结构;同时研究者还利用这种方法来将ES细胞诱导产生大脑皮层组织,并且促进小鼠的ES细胞分化形成胚胎的眼睛组织。
这项研究中,研究小组利用携带信号分子的细胞培养系统来诱导ES细胞分化形成处于外胚层的神经组织,研究者发现,这些ES细胞可以自组装形成神经上皮组织,随后其可以折叠形成多层脑皮层。
在人类胚胎发育期间,神经管会在两端加厚,尤其是大脑皮层前端会剧烈加厚,研究人员的一个重要发现就是,神经管前端加厚取决于径向神经胶质纤维的生长,神经胶质纤维可以沿着神经管生长并且引导细胞迁移。
与此同时这项研究也揭示了人类和小鼠神经管发育之间的关键差异,在人类机体中,神经管的内表面和神经上皮区域(位于神经管下)包含有很多不同的神经前体细胞来装配形成放射状胶质细胞,而在发育的小鼠大脑皮层中并不存在神经祖细胞。
最后研究者Kadoshima表示,大脑外皮组织的有效产生为神经元的功能发育以及医疗用组织的需求提供了很大帮助,通过结合特殊的人类诱导多能性干细胞技术,未来将会更加有效地治疗更为复杂的人类疾病。
原文链接:
doi:10.1073/pnas.1315710110
Self-organization of axial polarity, inside-out layer pattern, and species-specific progenitor dynamics in human ES cell–derived neocortex
Taisuke Kadoshimaa,b,1, Hideya Sakaguchia,b, Tokushige Nakanoa,2, Mika Soena, Satoshi Andoa,2, Mototsugu Eirakuc, and Yoshiki Sasaia,b,3
Here, using further optimized 3D culture that allows highly selective induction and long-term growth of human ES cell (hESC)-derived cortical neuroepithelium, we demonstrate unique aspects of self-organization in human neocorticogenesis. Self-organized cortical tissue spontaneously forms a polarity along the dorsocaudal-ventrorostral axis and undergoes region-specific rolling morphogenesis that generates a semispherical structure. The neuroepithelium self-forms a multilayered structure including three neuronal zones (subplate, cortical plate, and Cajal-Retzius cell zones) and three progenitor zones (ventricular, subventricular, and intermediate zones) in the same apical-basal order as seen in the human fetal cortex in the early second trimester. In the cortical plate, late-born neurons tend to localize more basally to early-born neurons, consistent with the inside-out pattern seen in vivo. Furthermore, the outer subventricular zone contains basal progenitors that share characteristics with outer radial glia abundantly found in the human, but not mouse, fetal brain. Thus, human neocorticogenesis involves intrinsic programs that enable the emergence of complex neocortical features.