日本研究人员经动物实验证实，脑神经细胞会激活神经干细胞中的某种蛋白质，向神经干细胞发出制造星形胶质细胞的指令。
研究人员在美国最新一期《发育细胞》（Development Cell）杂志上报告说，星形胶质细胞是脑内神经胶质细胞的一种，这类细胞有保护神经细胞并将血液中的养分提供给后者的作用。此前的研究表明，神经干细胞首先分化生成神经细胞，随后产生星形胶质细胞，但其中的具体机制不明。
日本奈良尖端科学技术研究生院大学教授中岛钦一领导的研究小组，将实验鼠的神经干细胞和神经细胞放置在同一个培养皿中培养后发现，星形胶质细胞产生较早。如果用药物抑制神经干细胞中Notch蛋白质的作用，星形胶质细胞就不能产生。
研究人员认为，人体内也有同样的机制在发挥作用。这项成果将来有望应用于再生医疗领域，以补充因脑梗塞或脊髓损伤而受损的神经细胞。（Bioon.com）
生物谷推荐原始出处：
Developmental Cell, 17 February 2009 doi:10.1016/j.devcel.2008.12.014
Committed Neuronal Precursors Confer Astrocytic Potential on Residual Neural Precursor Cells
Masakazu Namihira1,5,Jun Kohyama1,Katsunori Semi1,Tsukasa Sanosaka1,Benjamin Deneen2,Tetsuya Taga3,4andKinichi Nakashima1,,
1 Laboratory of Molecular Neuroscience, Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0101, Japan
2 Division of Biology 216-76, California Institute of Technology, Pasadena, CA 91125, USA
3 Division of Cell Fate Modulation, Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1 Honjo, Kumamoto 860-0811, Japan
4 Department of Stem Cell Regulation, Medical Research Institute, Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
5 Present address: Department of Human Genetics, David Geffen School of Medicine, University of California at Los Angeles, Los Angeles, CA 90095, USA
Summary
During midgestation, mammalian neural precursor cells (NPCs) differentiate only into neurons. Generation of astrocytes is prevented at this stage, because astrocyte-specific gene promoters are methylated. How the subsequent switch from suppression to expression of astrocytic genes occurs is unknown. We show in this study that Notch ligands are expressed on committed neuronal precursors and young neurons in mid-gestational telencephalon, and that neighboring Notch-activated NPCs acquire the potential to become astrocytes. Activation of the Notch signaling pathway in midgestational NPCs induces expression of the transcription factor nuclear factor I, which binds to astrocytic gene promoters, resulting in demethylation of astrocyte-specific genes. These findings provide a mechanistic explanation for why neurons come first: committed neuronal precursors and young neurons potentiate remaining NPCs to differentiate into the next cell lineage, astrocytes.
