How do you build an astrocyte?

项目摘要 星形胶质细胞是大脑发育和功能的重要调节器。星形胶质细胞获得了非常复杂的形态 这使得它们能够相互关联，与其他细胞类型（例如脉管系统）和它们调节的突触相关联。 突触发生，神经递质再摄取，代谢支持，离子平衡，最终动物行为。虽然 相信星形胶质细胞的精细形态对于星形胶质细胞的有效功能是绝对必要的，星形胶质细胞如何 这种异常复杂的体系结构仍然没有得到很好的定义。这是令人惊讶的，因为它们在神经系统中起着至关重要的作用。 电路的形成和功能，以及星形胶质细胞生长控制的破坏导致最棘手的， 致命的人脑肿瘤胶质母细胞瘤 星形胶质细胞是如何获得其独特的形态，以及它们是如何组织其亚细胞结构的 使其具有不同的功能？我们将尝试以果蝇星形胶质细胞为模型来回答这些核心问题。 果蝇星形胶质细胞在形态、发育、分子和生物学方面与哺乳动物星形胶质细胞非常相似， 果蝇提供了一系列强大的分子遗传学工具，可以用来探索基本的 星形胶质细胞生物学中的问题，在其他生物体中不存在。我们将开始全面描述 星形胶质细胞的细胞器景观，通过检查~30个遗传编码标记的分布， 标记细胞器（Aim 1）。这将使我们能够以单细胞的精度定义基本的细胞器结构 星形胶质细胞。这将是理解它们复杂形态是如何排列的重要的第一步 超微结构和它如何可能决定，或被调节，他们的功能。这些细胞地标也将使一个 对影响星形胶质细胞形态的突变体进行严格分析。在目标2中，我们将执行第一个无偏正向遗传算法， 筛选星形胶质细胞生长控制途径。为此，我们建立了一个独特的遗传筛查平台， 基于MARCM技术的果蝇，可以通过单细胞分辨率快速筛选突变体， 改变多种表型，包括细胞形态（生长、平铺、与突触的结合）、增殖变化， 或星形胶质细胞特性的其他变化。在初步工作中，我们已经优化了我们的筛选系统，沿着成像 最大限度地促进我们的工作。这是了解星形胶质细胞如何在体内构建的长期努力的一部分。 确定星形胶质细胞如何控制其细胞生长、浸润和平铺，对于我们更好地理解星形胶质细胞的作用至关重要。 星形胶质细胞如何影响大脑健康和疾病。由于这将是第一次对星形胶质细胞生长控制进行正向遗传筛选， 途径，大量令人兴奋的突变体等待发现。我们将把我们随后的努力集中在保守的途径， 哺乳动物星形胶质细胞，并考虑到苍蝇和 哺乳动物，我们希望我们的工作将确定一些新的高优先级的途径，了解星形胶质细胞 哺乳动物的形态发生

Project Summary Astrocytes are crucial regulators of brain development and function. Astrocytes acquire a remarkably complex morphology that allows them to associate with each other, other cell types (e.g. the vasculature) and synapses where they regulate synaptogenesis, neurotransmitter reuptake, metabolic support, ion balance, and ultimately animal behavior. While it is believed that the elaborate morphology of astrocytes is absolutely essential for efficient astrocyte function, how astrocytes acquire this unusually complex architecture remains poorly defined. This is surprising in light of their crucial roles in neural circuit formation and function, and the fact that disruption of astrocyte growth control results in the most intractable and deadly human brain tumor, glioblastoma. How do astrocytes acquire their remarkably morphology, and how do they organize their subcellular architecture to enable their diverse functions? We will attempt to answer these central questions using Drosophila astrocytes as a model. Fly astrocytes are remarkably similar to their mammalian counterparts by morphological, developmental, molecular, and functional criteria, and Drosophila offers a battery of powerful molecular-genetic tools with which to explore fundamental questions in astrocyte biology that are not available in other organisms. We will begin by comprehensively characterizing the cell-wide organellar landscape of astrocytes by examining the distribution of ~30 genetically encodable markers that label cellular organelles (Aim 1). This will allow us to define, with single-cell precision, the basic organellar architecture of astrocytes. This will be an essential first step toward understanding how their intricate morphology is arranged ultrastructurally and how it may dictate, or be regulate by, their functions. These cellular landmarks will also enable a rigorous analysis of mutants that affect astrocyte morphology. In Aim 2, we will perform the first unbiased forward genetic screen for astrocyte growth control pathways. We have established a unique genetic screening platform for this purpose in Drosophila based on MARCM technology, which allows for rapid screening with single-cell resolution for mutants that alter a variety of phenotypes including cell morphology (growth, tiling, association with synapses), changes in proliferation, or other changes in astrocyte properties. In preliminary work we have optimized our screening system, along with imaging methods to maximally facilitate our work. This is part of a long term effort to understand how astrocytes are built in vivo. Defining how astrocytes control their cell growth, infiltration, and tiling will be critical for us to gain a better understanding how astrocytes affect brain health and disease. Since this will be the first forward genetic screen for astrocyte growth control pathways, a wealth of exciting mutants await discovery. We will focus our subsequent efforts on pathways conserved in mammalian astrocytes, and given the strong conservation of the developmental and functional properties in flies and mammals, we expect our work will identify a number of new high-priority pathways for understanding astrocyte morphogenesis in mammals.