The role of purinergic signaling in mediating the dynamics of microglia repopulation following depletion in the adult cortex in vivo

项目摘要。小胶质细胞是大脑的免疫细胞，长期以来因其关键作用而受到赞赏 在脑损伤和疾病期间。然而，最近的研究表明小胶质细胞具有重要作用 在没有病理的情况下，有助于维持大脑稳态，支持神经元发育并帮助 发育和可塑性过程中神经回路的重塑。这使得小胶质细胞成为治疗靶点 神经回路发育或重塑不当的疾病。尽管它们对大脑很重要 对于健康和疾病，人们对小胶质细胞在大脑中定殖后如何自我维持知之甚少。 发展。这些知识对于理解小胶质细胞如何在整个过程中维持其功能至关重要。 寿命。虽然小胶质细胞是长寿细胞，但耗竭方法已证明成年小胶质细胞 群体可以通过驻留细胞的增殖快速重建。因为这些研究已经 在固定组织中进行该过程的动力学和机制尚不清楚。我建议确定如何 小胶质细胞在体内出生并成熟。我还将探讨嘌呤能受体 P2Y12 在此过程中的作用。 我假设小胶质细胞是由单个小胶质细胞分裂产生的，并且依赖于嘌呤能 信号传导以在形态和功能上快速分化以发挥其生理作用 大脑。为了检验这个假设，我将讨论两个相关但独立的目标。在目标 1 中，我有 开始测试以下假设：小胶质细胞通过单个存活小胶质细胞的快速分裂而重新增殖 正常条件下和实验耗尽后。我还表明小胶质细胞对于体验至关重要- 成人视觉皮层的依赖性可塑性。在目标 2 中，我将检验以下假设：生理属性 小胶质细胞的变化，例如过程运动和小胶质细胞突触相互作用，在小胶质细胞形成后不久就恢复到基线 都是在成年时出生的。我还将探讨 P2Y12 信号传导是否有助于这些属性的成熟 在新生的成年小胶质细胞中。最后，我将研究新生的小胶质细胞如何快速获得其功能 支持视觉皮层中依赖于经验的可塑性。这两个目标共同描述了小胶质细胞如何 增殖并维持成人皮质的稳态。因此，该提案体现了一套新的技术 这使得可以密切监测小胶质细胞的自我更新动态。我将在研究生中获得的培训 学校在执行第一个目标的同时，将为我在目标 3 中进行博士后研究做好准备，我将在那里进行 开展协作工作以确定治疗神经发育障碍的治疗目标。

Project Summary. Microglia are the brain’s immune cells and have long been appreciated for their critical roles during brain injury and disease. Recent studies, however, have demonstrated that microglia have important roles in the absence of pathology and serve to maintain brain homeostasis, support developing neurons and aid in the remodeling of neural circuitry during development and plasticity. This makes microglia a therapeutic target for diseases in which neural circuits either develop or remodel inappropriately. Despite their importance in brain health and disease, very little is known about how microglia self-maintain after they colonize the brain during development. This knowledge is fundamental to understanding how microglia maintain their functions throughout the lifespan. While microglia are long-lived cells, depletion methods have demonstrated that the adult microglial population can be rapidly reconstituted by the proliferation of resident cells. Because these studies have been carried out in fixed tissue the dynamics and mechanisms of this process are unclear. I propose to determine how microglia are born and mature in vivo. I will also explore the role of the purinergic receptor, P2Y12 in this process. I hypothesize that microglia are born by the division of single microglia and depend on purinergic signaling to rapidly differentiate morphologically and functionally to perform their physiological roles in the brain. In order to test this hypothesis, I will address two related but independent aims. In Aim 1, I have started to test the hypothesis that microglia repopulate from rapid division of single surviving microglia under normal conditions and after experimental depletion. I have also shown that microglia are critical to experience- dependent plasticity in the adult visual cortex. In Aim 2, I will test the hypothesis that the physiological attributes of microglia such as process motility and microglia-synapse interactions return to baseline soon after microglia are born in the adult. I will also explore whether P2Y12 signaling contributes to the maturation of these attributes in newly-born adult microglia. Lastly, I will examine how rapidly newly-born microglia acquire their functions that support experience-dependent plasticity in the visual cortex. Together these two aims characterize how microglia proliferate and maintain homeostasis in the adult cortex. Thus, this proposal embodies a new set of techniques that allows the close monitoring of the self-renewal dynamics of microglia. The training I will obtain in graduate school while performing the first to aims, will prepare me for my postdoctoral studies in Aim 3, where I will carry out collaborative work to determine therapeutic targets for the treatment of neurodevelopmental disorders.