Investigating novel mechanisms that underlie glial-mediated synapse elimination in development and aging

项目摘要 适当的神经元伴侣之间突触连接的形成和维持对于 正常的神经系统功能事实上，无论是最初的突触形成还是随后的突触形成， 发育性突触消除是许多神经发育障碍的基础。突触消除， 发生在适当的发育环境之外，是与年龄相关的突触丧失的基础。 认知能力下降和神经退行性疾病。因此，确定监管的基础机制 突触数量的变化将有助于了解发育过程中如何形成适当的连接， 这些突触消失的病理学。 尽管它在神经系统发育和功能中起着重要作用，但我们对它仍然知之甚少。 这一过程背后的机制。然而，我们知道神经胶质是必需的。为了识别新的 神经胶质调节突触发育，我完成了果蝇的正向遗传筛选，并确定了91 这些分子在神经胶质细胞中被击倒后，会改变突触的数量。在这些分子中， Crq受体，我发现它是神经胶质细胞在发育过程中消除突触所必需的。该提案将重点 了解Crq在突触消除中的作用，以便深入了解更大的问题， 突触经历发育性突触消除，这一特异性的潜在机制 过程，以及这些相同的机制是否在与衰老相关的病理性突触丧失中被重复使用。 目标1将解决的问题，哪些突触经历发育消除整个神经 系统，并评估其中哪些是Crq依赖。我最近开发了一种诱导性突触前 标签，使这项工作成为可能，并将产生可诱导的突触后标签作为这一目标的一部分。目标2将 使用邻近标记来识别Crq的神经元配体，其作用是指定哪些突触经历 消除，并将确定这些配体的表达和定位是如何调节的。目标3将定义 哪些突触随着年龄的增长而丢失，并确定Crq是否作为突触丢失的共同介质， 发育和衰老。我也会根据最近的转录分析进行一次有针对性的筛查 我完成了一个实验，以确定与年龄相关的突触丢失的其他神经胶质调节因子。 总之，这些研究将解决突触被靶向消除的机制以及如何消除。 这是一个关键问题，在实现更大的目标，了解神经元和胶质细胞如何共同努力， 在一生中建立并维持适当的突触连接。剖析这些机制也将 提供了深入了解与年龄相关的突触损失的过程，这是与年龄相关的认知衰退的基础。在 此外，执行这项工作将使我能够解决我的技术技能，使我能够 作为一名独立的调查员，实现我的长期研究目标。

Project Summary Formation and maintenance of synaptic connections between appropriate neuronal partners is essential for proper nervous system function. Indeed, impairments in either initial synapse formation or in subsequent developmental synapse elimination underlie many neurodevelopmental disorders. Synapse elimination that occurs outside of appropriate developmental contexts underlies synaptic loss associated with age-related cognitive decline and in neurodegenerative diseases. Thus, defining the mechanisms that underlie the regulation of synapse number will provide insight into how appropriate connections are formed during development, and these pathologies of synapse elimination. Despite its essential role in nervous system development and function throughout life, we still know little about the mechanisms underlying this process. We do know, however, that glia are required. In order to identify novel glial regulators of synapse development, I completed a forward genetic screen in Drosophila, and identified 91 molecules that, when knocked down in glia, alter synapse number. Among these molecules is the immune receptor Crq, which I found is required for glial elimination of synapses in development. This proposal will focus on understanding Crq’s role in synapse elimination, in order to gain insight into the larger questions of which synapses undergo developmental synapse elimination, the mechanisms underlying the specificity of this process, and whether these same mechanisms are re-used in pathological synapse loss associated with aging. Aim 1 will address the question of which synapses undergo developmental elimination across the nervous system and evaluate which of these are Crq-dependent. I have recently developed an inducible pre-synaptic label that makes this work possible, and will generate inducible postsynaptic labels as part of this aim. Aim 2 will use proximity labeling to identify the neuronal ligand(s) for Crq that act to specify which synapses undergo elimination, and will identify how expression and localization of these ligands are regulated. Aim 3 will define which synapses are lost with aging, and identify whether Crq acts as a common mediator of synaptic loss in development and aging. I will also perform a targeted screen based on a recent transcriptional profiling experiment I completed to identify additional glial regulators of age-related synaptic loss. Together, these studies will address the mechanisms by which synapses are targeted for elimination and how. This is a key question in achieving the larger goal of understanding how neurons and glia work together to create and maintain appropriate synaptic connections throughout life. Dissecting these mechanisms will also provide insight into the process of age-related synaptic loss that underlies age-related cognitive decline. In addition, performing this work will allow me to address existing gaps in my technical skills that will allow me to carry out my long-term research goals as an independent invesitigator.