日本研究人員經(jīng)動物實驗證實，腦神經(jīng)細(xì)胞會激活神經(jīng)干細(xì)胞中的某種蛋白質(zhì),，向神經(jīng)干細(xì)胞發(fā)出制造星形膠質(zhì)細(xì)胞的指令。
研究人員在美國最新一期《發(fā)育細(xì)胞》（Development Cell）雜志上報告說,，星形膠質(zhì)細(xì)胞是腦內(nèi)神經(jīng)膠質(zhì)細(xì)胞的一種,，這類細(xì)胞有保護(hù)神經(jīng)細(xì)胞并將血液中的養(yǎng)分提供給后者的作用。此前的研究表明,，神經(jīng)干細(xì)胞首先分化生成神經(jīng)細(xì)胞,，隨后產(chǎn)生星形膠質(zhì)細(xì)胞，但其中的具體機制不明,。
日本奈良尖端科學(xué)技術(shù)研究生院大學(xué)教授中島欽一領(lǐng)導(dǎo)的研究小組,，將實驗鼠的神經(jīng)干細(xì)胞和神經(jīng)細(xì)胞放置在同一個培養(yǎng)皿中培養(yǎng)后發(fā)現(xiàn)，星形膠質(zhì)細(xì)胞產(chǎn)生較早,。如果用藥物抑制神經(jīng)干細(xì)胞中Notch蛋白質(zhì)的作用,，星形膠質(zhì)細(xì)胞就不能產(chǎn)生。
研究人員認(rèn)為,，人體內(nèi)也有同樣的機制在發(fā)揮作用,。這項成果將來有望應(yīng)用于再生醫(yī)療領(lǐng)域，以補充因腦梗塞或脊髓損傷而受損的神經(jīng)細(xì)胞,。（Bioon.com）
生物谷推薦原始出處：
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.
