Molecular pathways regulating astrocyte morphogenesis and function

总结 星形胶质细胞是人脑中最丰富的胶质细胞类型，对中枢神经系统至关重要 (CNS)发展和功能。成熟的星形胶质细胞是异常复杂的细胞，具有复杂的， 分枝形态学它们众多的精细细胞突起与突触、神经元细胞 体、轴突、血管和整个CNS的其他神经胶质细胞。通过这些相互作用，星形胶质细胞 实现多种功能以支持和增强神经元活性，维持CNS稳态，并调节 电路.强调了星形胶质细胞正常发育的重要性，星形胶质细胞生长缺陷或 星形胶质细胞复杂性与许多神经系统疾病有关，包括亚历山大病、自闭症和 癫痫然而，对于星形胶质细胞是如何形成其复杂的形态结构的， 关联和调节神经回路功能。 我们的长期目标是了解星形胶质细胞是如何获得其显着的形态，靶向它们的细胞， 突触，并使用这些细胞与细胞的接触来调节大脑功能。我们最近进行了一次 在果蝇中进行遗传筛选，以确定星形胶质细胞发育的新调节因子，并发现了一个新的基因， 被困在内胚层1（Tre 1），如星形胶质细胞形态发生所需。我们发现，Tre 1的缺失导致 严重降低了体内星形胶质细胞的复杂性，导致突触神经元浸润减少。Tre 1 编码G蛋白偶联受体（GPCR），在CNS中没有已知的功能。该提案将使用一个 果蝇和斑马鱼中可用分子遗传工具与新工具的协同组合沿着 我们已经产生了体内成像，以确定Tre 1如何调节星形胶质细胞的形态发生，功能， 和果蝇的动物行为（目的1）;阐明Tre 1上游和下游的信号通路 激活（目标1+2）;并确定Tre 1在脊椎动物中的进化保守性（目标3）。我们的工作将 为调节体内星形胶质细胞发育和功能的机制提供了令人兴奋的新见解， 为了解人类疾病中星形胶质细胞的生长和功能障碍奠定基础。

SUMMARY Astrocytes are the most abundant glial cell type in the human brain and are critical for central nervous system (CNS) development and function. Mature astrocytes are unusually elaborate cells, with an intricate and ramified morphology. Their numerous fine cellular processes interact closely with synapses, neuronal cell bodies, axons, blood vessels, and other glial cells throughout the CNS. Through these interactions, astrocytes fulfil diverse functions to support and enhance neuronal activity, maintain CNS homeostasis, and modulate circuits. Underscoring the importance of proper astrocyte development, defects in astrocyte growth or loss of astrocyte complexity are implicated in many neurological diseases, including Alexander's disease, autism, and epilepsy. However, it remains poorly understood how astrocytes develop their intricate morphological associations and regulate neural circuit function. Our long-terms goals are to understand how astrocyte acquire their remarkable morphology, target their processes to synapses, and use these cell-cell contacts to modulate brain function. We recently performed a genetic screen in Drosophila to identify new regulators of astrocyte development, and uncovered a novel gene, Trapped in endoderm 1 (Tre1), as required for astrocyte morphogenesis. We find that loss of Tre1 leads to severely reduced astrocyte complexity in vivo, resulting in decreased infiltration of the synaptic neuropil. Tre1 encodes a G protein-coupled receptor (GPCR) with no known function in the CNS. This proposal will use a synergistic combination of molecular-genetic tools available in Drosophila and zebrafish along with new tools we have generated and in vivo imaging to: determine how Tre1 regulates astrocyte morphogenesis, function, and animal behavior in Drosophila (Aim 1); elucidate signaling pathways upstream and downstream of Tre1 activation (Aims 1+2); and define the evolutionary conservation of Tre1 in vertebrates (Aim 3). Our work will provide exciting new insights into the mechanisms regulating astrocyte development and function in vivo and lay the foundation for understanding astrocyte growth and dysfunction in human disease.