COLLABORATIVE RESEARCH: Role of Glia during Postembryonic Formation of the CNS

摘要-合作研究：Fahrbach和Mesce昆虫的变态伴随着中枢神经系统的广泛重组。这些变化是由类固醇激素调节的，在变态过程中，昆虫神经元和胶质细胞表达核类固醇激素受体。飞蛾和蝴蝶神经系统变态的一个显著特征是由单个节段神经节形成复合神经节。Manduca sexta是一种很容易在实验室中饲养的大型物种，在毛虫化蛹后不久，复合神经节就形成了。这个合作项目将测试一个复合神经节形成的模型，其中两类胶质细胞是类固醇的主要靶点。在这个模型中，神经节间连接的巨大神经胶质细胞通过改变其细胞结构来移动神经元簇，而包裹中枢神经系统的神经周围神经胶质细胞改变其粘附特性以允许神经元自由移动。将在明尼苏达大学Mesce博士的实验室进行的实验将描述复合神经节形成过程中巨胶质细胞的运动，并将研究巨胶质细胞的损伤如何影响神经节的迁移和融合。这些实验是由于最近发现的一种形式的束状蛋白II，一种在昆虫细胞表面表达的蛋白质，可以用作巨大胶质细胞的标记物。在伊利诺伊大学厄巴纳-香槟分校Fahrbach博士的实验室进行的实验将确定变形过程中神经周围胶质细胞增殖的时间，并研究该细胞群消融对神经节迁移和融合的影响。此外，针对昆虫类固醇激素受体（蜕皮激素受体，EcR）的特定同种异构体的抗体将用于确定胶质细胞表达哪种形式的受体。这被设想为鉴定类固醇调节基因参与调节胶质细胞骨架和胶质细胞粘附分子的第一步。以前对昆虫神经系统变态的研究只集中在神经元上。本项目将为昆虫胚胎后期神经胶质细胞结构和黏附性的发育调控提供新的信息。这个结果很可能推广到所有节肢动物，因为细胞“粘性”和细胞形状的调节是所有多细胞生物的基本属性，所以也适用于其他动物。

Lay Summary - Collaborative Research: Fahrbach and Mesce Insect metamorphosis is accompanied by extensive reorganization of the central nervous system. These changes are regulated by steroid hormones, and during metamorphosis insect neurons and glia express nuclear steroid hormone receptors. A notable feature of metamorphosis in the nervous system of moths and butterflies is the formation of compound ganglia from individual segmental ganglia. In the moth Manduca sexta, a large species easily reared in the laboratory, compound ganglia form shortly after the caterpillar pupates. This collaborative project will test a model of compound ganglion formation in which two classes of glial cells are the primary steroid targets. In this model, the giant glial cells of the interganglionic connectives move clusters of neurons by changes in their cytoarchitecture while the perineurial glial cells that wrap the central nervous system alter their adhesive properties to permit the neurons to move freely. Experiments to be conducted at the University of Minnesota in Dr. Mesce's laboratory will describe the motility of giant glial cells during the formation of compound ganglia and will study how damage to the giant glial cells affects ganglionic migration and fusion. These experiments are facilitated as a result of the recent discovery that a form of fasciclin II, a protein expressed on the surface of insect cells, can be used as a marker for the giant glial cells. Experiments to be conducted in Dr. Fahrbach's laboratory at the University of Illinois at Urbana-Champaign will determine the timing of perineurial glial cell proliferation during metamorphosis and study the effects of ablation of this cell population on ganglionic migration and fusion. In addition, antibodies targeted to specific isoforms of the insect steroid hormone receptor (the ecdysone receptor, EcR) will be used to determine which form of the receptor is expressed by glial cells. This is envisioned as a first step toward identifying steroid-regulated genes involved in regulation of the glial cytoskeleton and glial cell adhesion molecules.Previous studies of metamorphosis of the insect nervous system have focused exclusively on neurons. This project will provide new information about the developmental modulation of glial cell cytoarchitecture and glial cell adhesivity during the postembryonic life of insects. The results are likely to generalize to all arthropods and, because the regulation of cell "stickiness" and cell shape are fundamental attributes of all multicellular organisms, to other animals as well.