Structure and function of a novel population of regenerating ependymal cells

项目总结 实验室已经发现了一种新型的室管膜细胞(E2)，它有两根由两个基底部固定的长纤毛 比其他细胞大30-100倍的小体(Mirzadeh等人)。2008、2017)。E2细胞存在于 脑室系统的关键位置，靠近外侧壁中的神经干细胞(NSCs) 脑室和第三和第四脑室对摄食和血糖调节至关重要的区域，昼夜节律 节奏、意识、警觉和睡眠(Mirzadeh等人)。2017年)。有趣的是，类E2细胞也 在室管膜瘤中观察到，这表明与增殖的祖细胞和癌症有关(Alfaro-Cervellóet al. 2015年；Ho，Caccamo和Garcia，1994)。E2细胞的遗传图谱，其组成和组织 独特的纤毛和基体，它们的发育起源，它们的再生能力和它们的功能 为人所知。室管膜(E)细胞仍然是大脑中最不被了解的神经胶质细胞类型之一，然而这些细胞 参与正常大脑功能所必需的功能。多纤毛室管膜(E1)细胞，通过 它们~50个活动纤毛的协调跳动，有助于脑脊液(CSF)流动，并被要求 预防脑积水(Jiménez等人)。2014年；Ohata和Alvarez-Buylla，2016年；Banizs等人。2005)。在侧边 脑室，E细胞参与成体神经干细胞(NSCs)的调节和神经元的迁移 成人大脑最大的生发区：脑室-脑室下区(V-SVZ)。E细胞如何感知和 将脑脊液信号传递到这个生发利基仍不清楚。E2细胞不太可能通过它们的两根纤毛 对脑脊液流量有显著贡献。相反，我们认为E2纤毛和基底体可能在 脑脊液信号的检测。它们位于脑脊液和重要脑区的交界处 这有力地表明，它们在大脑功能中扮演着关键的角色，但迄今尚未确定。令人惊讶的是，初步数据 表明侧脑室E2细胞寿命相对较短，数量随年龄增长而减少，并且 在成年小鼠体内不断再生。我们建议：1)表征E2细胞及其纤毛和基底体 利用单细胞基因表达分析、电子显微镜和超高分辨率显微镜；2)确定 E2细胞的发育和成体种群动态，并鉴定产生新的E2的祖细胞 成人中的细胞(初步证据表明，E2细胞来自成人神经干细胞)；以及3)调查 E2细胞纤毛信号是否通过有条件地删除关键纤毛来调节成体干细胞巢功能 信号分子在E2细胞中富含。这一新知识将对破译E2的功能至关重要 成体V-SVZ内的细胞。此外，在E2细胞中发现的分子标记和信号通路可能会有所帮助 了解某些室管膜瘤的细胞起源和生长控制。鉴于E2细胞存在于 第三脑室和第四脑室，以及中央管，旁边是非常重要的功能区域，这一新的 了解这一点也将有助于研究整个大脑中的E细胞功能。

PROJECT SUMMARY The laboratory has identified a novel type of ependymal cell (E2) that has two long cilia anchored by two basal bodies that are 30-100 fold larger than those in other cells (Mirzadeh et al. 2008, 2017). E2 cells are found in strategic locations of the ventricular system, next to Neural Stem Cells (NSCs) in the walls of the lateral ventricle and in regions of the third and fourth ventricle critical to feeding and glucose regulation, circadian rhythms, consciousness, alertness and sleep (Mirzadeh et al. 2017). Interestingly, E2-like cells have been also observed in ependymomas, suggesting a link to proliferating progenitors and cancer (Alfaro-Cervelló et al. 2015; Ho, Caccamo, and Garcia 1994). E2 cells' genetic profile, the composition and organization of their unique cilia and basal bodies, their developmental origin, their regenerative capacity, and their function are not known. Ependymal (E) cells remain one of the least understood glial cell types in the brain, yet these cells are involved in functions that are essential for proper brain function. Multiciliated ependymal (E1) cells, through the coordinated beating of their ~50 motile cilia, contribute to cerebrospinal fluid (CSF) flow, and are required to prevent hydrocephalus (Jiménez et al. 2014; Ohata and Alvarez-Buylla 2016; Banizs et al. 2005). In the lateral ventricles, E cells contribute to the regulation of adult neural stem cells (NSCs) and neuronal migration in the largest germinal zone of the adult brain: the ventricular-subventricular zone (V-SVZ). How E cells sense and transmit CSF signals to this germinal niche remains unknown. It is unlikely that E2 cells through their two cilia contribute significantly to CSF flow. Instead, we propose that E2 cilia and basal body could play a key role in the detection of CSF signals. Their location at the interface between the CSF and important brain regions strongly suggests they have pivotal, as-yet unidentified, roles in brain function. Surprisingly, preliminary data indicate that the lateral ventricle E2 cells are relatively short-lived, decrease in number with age, and are constantly regenerated in adult mice. We propose to: 1) characterize E2 cells and their cilia and basal bodies using single cell gene expression analysis, electron and ultra-high resolution microscopy; 2) determine the development and adult population dynamics of E2 cells, and identify the progenitor cells giving rise to new E2 cells in the adult (preliminary evidence suggests that E2 cells are derived from adult NSCs); and 3) investigate whether E2 cell cilia signaling modulates adult stem cell niche function, using conditional deletion of a key cilia signaling molecule enriched in E2 cells. This new knowledge will be essential to decipher the function of E2 cells in the adult V-SVZ. In addition, molecular markers and signaling pathways identified in E2 cells could help understand the cell of origin and growth control of some ependymomas. Given the presence of E2 cells in the third and fourth ventricles, and central canal, next to regions of great functional importance, this new understanding will also help studies of E cell function throughout the brain.