Endogenous barcoding to determine complex dynamics of adult neurogenesis in aging and Alzheimer's disease

摘要 成年人和动物海马体中的新神经元与几种认知功能有关。 功能协调发展的这些功能由于新神经元的丧失或产生不足而严重受损。神经元 是在一系列长时间的转变后产生的，包括激活、增殖、消除和 神经干细胞及其后代的分化。竞争的假设已经被提出来描述 如何执行这些步骤。这些假设意味着不同的，有时是矛盾的，蓝图的 从干细胞到神经元的转变，以及当这些蓝图受到干扰时的不同结果。 衰老或疾病。阿尔茨海默病（AD）对海马神经发生有显著的不利影响， 在人类和动物模型中，这种减少被认为与认知功能障碍直接相关。 在AD中观察识别AD诱导的神经发生的变化，并将其与 衰老引起的变化可能揭示了减轻甚至逆转AD相关认知功能的新方法。 立刻这一目标是具有挑战性的，不仅因为系统的复杂性，而且因为 目前可用于追踪干细胞及其后代的方法中固有的局限性。 我们最近开发了一种新的内源性条形码化方法来确定谱系轨迹， 以及成年小鼠脑中神经干细胞的分化轨迹。此外，我们还开发了一个 新技术的组合多标签标记的亚群分裂干细胞和他们的后代。现在 我们建议应用这些新的方法来确定AD和衰老引起的基础 神经干细胞分裂和分化的方案，并研究如何减轻这些变化。 在我们的第一个具体目标中，我们将Polylox条形码盒和相关基因引入基因组中， 应用重组诱导的内源性条形码化，并进行条形码分析 与单细胞转录组分析相结合，作为确定细胞分裂，分化， 以及个体神经干细胞的谱系，以及AD和衰老造成的变化。在我们的第二 目的是，我们将应用我们的新技术，多标签标记分裂细胞，以进一步确定动态的 成年神经发生和AD和衰老引起的扰动。总之，这些方法将提供 新的手段解剖的扰动，在神经发生引起的老化和AD。最后，我们的第三个目标， 我们将确定这些变化是如何被用于不同治疗方式的药物所改变的， 作为进一步揭示AD和衰老诱导的变化的实验工具。

ABSTRACT New neurons in the adult human and animal hippocampus have been implicated in several cognitive functions. These functions are profoundly impaired by the loss or insufficient production of new neurons. Neurons are produced after a prolonged series of transitions including the activation, proliferation, elimination, and differentiation of neural stem cells and their progeny. Competing hypotheses have been proposed to describe how these steps are executed. These hypotheses imply divergent, sometimes contradicting, blueprints of the transitions from stem cells to neurons, as well as different outcomes when these blueprints are perturbed by aging or disease. Alzheimer's disease (AD) has a dramatic adverse effect on hippocampal neurogenesis in humans and in animal models, and this decrease is thought to be directly linked to the cognitive dysfunction observed in AD. Identifying the changes in neurogenesis induced by AD and differentiating them from the changes induced by aging may reveal new means of mitigating or even reversing AD-associated cognitive impartment. This goal is challenging not only because of the complexity of the system, but also because of the limitations inherent in currently available approaches for tracing stem cells and their progeny. We have recently developed a novel approach of endogenous barcoding to determine the lineage trajectory and differentiation trajectories of neural stem cells in the adult mouse brain. In addition, we have developed a new technique for combinatorial multitag labeling of subpopulations of dividing stem cells and their progeny. Now we propose applying these new approaches to identify the changes that AD and aging induce in the basic scheme of neural stem cell division and differentiation and to examine how those changes can be mitigated. In our first specific aim, we will introduce the Polylox barcode cassette and related genes into the genome of mouse models of AD, apply recombination-induced endogenous barcoding, and perform barcode analysis integrated with single-cell transcriptome analysis as a novel approach for determining the division, differentiation, and lineages of individual neural stem cells, as well as the changes inflicted by AD and aging. In our second aim, we will apply our new technique of multitag labeling of dividing cells to further determine the dynamics of adult neurogenesis and perturbations introduced by AD and aging. Together, these approaches will provide a new means of dissecting the perturbations in neurogenesis provoked by aging and AD. Finally, in our third aim, we will determine how these changes are modified by drugs used in different therapy modalities, using them here as experimental instruments for further revealing the AD- and aging-induced changes.