本帖最后由 细胞海洋 于 2010-9-19 07:16 编辑 4 T" w3 U* F. Q. i# E3 _- `/ m
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9月13日,日本理化研究所发布新闻公报称，该所研究人员成功诱导小鼠胚胎干细胞，有选择性地分化成小脑神经细胞，且实现了较高的分化效率。 , V5 v8 h" ]# _* d- S* v: v, B4 u/ M C1 Q# ~4 @6 B
公报说，小脑皮质中层内的浦肯雅细胞是掌管精确运动和学习的主要神经细胞，在医学方面具有相当重要的作用，以往诱导胚胎干细胞有选择性地分化成浦肯雅细胞的方法效率低下，只有约0．5％的胚胎干细胞最终能分化成浦肯雅细胞。 : c8 v& Y5 ~! d F w5 g- C8 |+ x6 L" t
理化研究所发展生物学研究中心的研究小组，改进了此前培育大脑神经细胞的无血清浮游培养法，开发出一种能在试管内再现胚胎发育过程中小脑发育环境的新方法。0 \4 g0 w! h1 e* e# u
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在实验中用这种方法诱导小鼠胚胎干细胞分化时，约80％的胚胎干细胞分化成了浦肯雅细胞的祖细胞，这其中又有约30％的祖细胞最后形成了浦肯雅细胞。将如此分化形成的细胞在试管中培育一段时间后，通过电生理学分析，研究人员观察到这些细胞拥有浦肯雅细胞特有的神经活动，从而证实这些细胞确实具备浦肯雅细胞的功能。 / @; f. K& ^- D# z' Y- @9 Y- b3 V9 ^. @
在移植实验中，研究人员将提纯后的浦肯雅细胞的祖细胞，移植入小鼠胚胎的小脑中，移植细胞顺利“扎根”在小脑的浦肯雅细胞层中，并正确融入小脑回路。- x/ m2 r0 v' p, j2 v$ B( J
) J5 W6 M0 U8 W( V/ @, L. O公报说，脊髓小脑变性症是小脑神经细胞因逐渐萎缩、死亡而数量减少导致的疾病，这项成果为此类疾病的病理研究和开发新疗法提供了新途径。 2 [8 m4 Y. t d0 q$ i% x; o7 g* Z( |" a& \% G* H( Z
生物谷推荐英文摘要：; J9 B1 ]5 w! t! y* J0 F# x
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Nature Neuroscience doi:10.1038/nn.2638* F x' k# ?$ c
/ j& B9 Y* D( Y" H& rOntogeny-recapitulating generation and tissue integration of ES cell–derived Purkinje cells 9 O8 K9 l# B) f0 _5 l, IKeiko Muguruma,Ayaka Nishiyama,Yuichi Ono,Hiroyuki Miyawaki,Eri Mizuhara,Seiji Hori,Akira Kakizuka,Kunihiko Obata,Yuchio Yanagawa,Tomoo Hirano& Yoshiki Sasai 6 _7 ~2 @6 l' n7 i1 [/ Z% M- F) v# ^+ \& Z
Purkinje cells are the sole output neurons of the cerebellar cortex and their dysfunction causes severe ataxia. We found that Purkinje cells could be robustly generated from mouse embryonic stem (ES) cells by recapitulating the self-inductive signaling microenvironments of the isthmic organizer. The cell-surface marker Neph3 enabled us to carry out timed prospective selection of Purkinje cell progenitors, which generated morphologically characteristic neurons with highly arborized dendrites that expressed mature Purkinje cell–specific markers such as the glutamate receptor subunit GluRδ2. Similar to mature Purkinje cells, these neurons also showed characteristic spontaneous and repeated action potentials and their postsynaptic excitatory potentials were generated exclusively through nonNMDA glutamate receptors. Fetal transplantation of precursors isolated by fluorescence-activated cell sorting showed orthotopic integration of the grafted neurons into the Purkinje cell layer with their axons extending to the deep cerebellar nuclei and dendrites receiving climbing and parallel fibers. This selective preparation of bona fide Purkinje cells should aid future investigation of this important neuron.3 L* C V% u. f2 I P; y( m