Omoto Jaison Jiro, Yogi Puja, Hartenstein Volker
Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA.
Department of Molecular Cell and Developmental Biology, University of California, Los Angeles, CA 90095, USA.
Dev Biol. 2015 Aug 15;404(2):2-20. doi: 10.1016/j.ydbio.2015.03.004. Epub 2015 Mar 14.
Glia comprise a conspicuous population of non-neuronal cells in vertebrate and invertebrate nervous systems. Drosophila serves as a favorable model to elucidate basic principles of glial biology in vivo. The Drosophila neuropil glia (NPG), subdivided into astrocyte-like (ALG) and ensheathing glia (EG), extend reticular processes which associate with synapses and sheath-like processes which surround neuropil compartments, respectively. In this paper we characterize the development of NPG throughout fly brain development. We find that differentiated neuropil glia of the larval brain originate as a cluster of precursors derived from embryonic progenitors located in the basal brain. These precursors undergo a characteristic migration to spread over the neuropil surface while specifying/differentiating into primary ALG and EG. Embryonically-derived primary NPG are large cells which are few in number, and occupy relatively stereotyped positions around the larval neuropil surface. During metamorphosis, primary NPG undergo cell death. Neuropil glia of the adult (secondary NPG) are derived from type II lineages during the postembryonic phase of neurogliogenesis. These secondary NPG are much smaller in size but greater in number than primary NPG. Lineage tracing reveals that both NPG subtypes derive from intermediate neural progenitors of multipotent type II lineages. Taken together, this study reveals previously uncharacterized dynamics of NPG development and provides a framework for future studies utilizing Drosophila glia as a model.
神经胶质细胞在脊椎动物和无脊椎动物的神经系统中构成了一个显著的非神经元细胞群体。果蝇是阐明体内神经胶质生物学基本原理的理想模型。果蝇神经纤维网神经胶质细胞（NPG）可细分为星形胶质细胞样（ALG）和包被神经胶质细胞（EG），它们分别延伸出与突触相关的网状突起和围绕神经纤维网区室的鞘状突起。在本文中，我们描述了果蝇全脑发育过程中NPG的发育情况。我们发现，幼虫脑内分化的神经纤维网神经胶质细胞起源于位于脑基部的胚胎祖细胞衍生的一群前体细胞。这些前体细胞经历特征性迁移，在神经纤维网表面扩散，同时特化/分化为初级ALG和EG。胚胎来源的初级NPG是数量较少的大细胞，在幼虫神经纤维网表面占据相对固定的位置。在变态过程中，初级NPG发生细胞死亡。成虫的神经纤维网神经胶质细胞（次级NPG）在神经胶质发生的胚胎后期阶段源自II型谱系。这些次级NPG的体积比初级NPG小得多，但数量更多。谱系追踪显示，两种NPG亚型均源自多能II型谱系的中间神经祖细胞。综上所述，本研究揭示了NPG发育中以前未被描述的动态变化，并为未来利用果蝇神经胶质细胞作为模型的研究提供了一个框架。
