Revealing the cellular and transcriptome dynamics underlying vertebrate neural development and regeneration.

急性损伤，如中风和创伤或慢性神经退行性疾病，会导致神经元和大脑功能的破坏，从而在世界范围内给人类健康造成重大负担。神经元不能分裂，但主要是在胎儿发育期间由增殖的神经胶质前体细胞形成的。在成年哺乳动物的大脑中，神经元的形成及其与现有回路的整合仅限于较小的特定脑区，导致大多数脑区缺乏内源性再生能力。与哺乳动物相比，斑马鱼在许多脑区具有明显和广泛的成体神经发生，并能在损伤后有效地再生脑组织。因此，斑马鱼是成功再生的模型，并可以在脊椎动物的大脑中研究这一过程的机制。然而，成年斑马鱼大脑再生的细胞和分子机制仍不完全清楚。我们最近设计了一种方法来前瞻性地分离成年斑马鱼脑中的放射状胶质细胞、神经前体细胞及其后代，并通过单细胞测序对这些细胞进行分析。这些实验揭示了一个出人意料的大量放射状胶质细胞来源的新生神经元池，这表明了区域身份和细胞命运的多样性。在这里，我们将对新生神经元进行谱系追踪和细胞消融，以分析它们在动态平衡和损伤的成年端脑中的细胞命运或评估它们对脑再生的需求。进一步，我们将通过分析刺伤后放射状胶质细胞及其神经元后代的单细胞转录本，来破译参与脑损伤后再生的分子程序和细胞分化机制。这些研究还将以细胞分辨率揭示放射状胶质细胞对损伤的反应动力学，并提供一种手段来比较鱼类和哺乳动物成年神经发生中的细胞类型和分子程序。最后，利用之前发表的高度增殖的幼年斑马鱼大脑的scRNAseq数据，比较动态平衡和再生的成年斑马鱼大脑中的分子程序和网络与幼年斑马鱼的情况，以确定再生的特异性特征。通过拟议的项目，我们将对脊椎动物脑再生的机制产生新的见解，对鱼类和哺乳动物的脑细胞类型进行进化比较，并确定新生未成熟神经元在脑再生中的功能作用。

Acute injuries such as stroke and trauma or chronic neurodegenerative diseases result in the destruction of neurons and floss of brain function, thereby causing a major burden to human health worldwide. Neurons are unable to divide, but are formed by proliferating glial progenitors mostly during fetal development. In the adult mammalian brain, formation of neurons and their integration into existing circuits is confined to small specific brain areas, leaving most brain areas devoid of endogenous regeneration capabilities. In contrast to mammals, zebrafish possess pronounced and widespread adult neurogenesis in many brain regions and can regenerate brain tissue efficiently after injury. Thus, zebrafish are a model for successful regeneration and allow to study the mechanisms of this process in the vertebrate brain. However, the cellular and molecular mechanisms of regeneration in the adult zebrafish brain are still incompletely understood. We have recently devised a method to prospectively isolate radial glia, the neuronal progenitors and their progeny in the adult zebrafish brain and analyzed these cells by single cell sequencing. These experiments revealed an unexpectedly large pool of radial glia derived newborn neurons, which showed diversity in regional identity and cell fate. Here, we will perform lineage tracing and cell ablation of newborn neurons to analyze their cell fate in the homeostatic and injured adult telencephalon or evaluate their requirement for brain regeneration, respectively. Further, we will decipher the molecular programs and cellular differentiation mechanisms involved in brain regeneration after injury by analyzing single cell transcriptomes of radial glia and their neuronal progeny after stab lesion. These investigations will also reveal the dynamics of radial glia reaction to injury with cellular resolution and provide a means to compare cell types and molecular programs in adult neurogenesis between fish and mammals. Finally, taking advantage of previously published scRNAseq data from the highly proliferative juvenile zebrafish brain, compare molecular programs and networks in the homeostatic and regenerating adult zebrafish brain with the juvenile situation in order to identify regeneration-specific traits. With the proposed project, we will generate novel insights into the mechanisms of vertebrate brain regeneration, perform evolutionary comparison of brain cell types in fish and mammals and define the functional role of newborn, immature neurons for brain regeneration