Microglial regulation of neuronal activity in TDP-43 neurodegeneration

项目摘要 小胶质细胞作为中枢神经系统的常驻免疫细胞，是衰老和 神经退行性疾病，如阿尔茨海默病（AD）和AD相关性痴呆（ADRD）。但是，在这方面， 小胶质细胞如何感知和调节神经变性仍然是未知的。TDP-43是一种DNA结合剂， 是肌萎缩侧索硬化症（ALS）中发现的蛋白质聚集体的主要成分的蛋白质， 额颞叶痴呆（FTLD）和AD。我们采用诱导型TDP-43易位小鼠模型， （rNLS 8），其可以模拟TDP-43相关神经变性的特征性特征。利用体内两个- 光子成像，我们已经证明，rNLS 8小鼠显示在皮层神经元过度活跃， 疾病进展，这与独特的杆状小胶质细胞沿沿着神经元树突排列有关 在第四层皮层。基于这些令人兴奋的观察，我们假设小胶质细胞具有 通过调节皮层微回路和减弱神经元过度活跃来发挥神经保护作用， 对TDP-43相关神经变性的反应。我们将通过以下三个目标来检验这一假设： 目的1：确定TDP-43神经变性中小胶质细胞激活的功能异质性。 我们将使用慢性的体内双光子成像来确定小胶质细胞的时空激活， 包括过程动态、景观变化和扩散。此外，我们将检查小胶质细胞Ca 2 + 使用新开发的小胶质细胞GCaMP 7s小鼠系的活性和TREM 2依赖性。的结果 该目的将揭示TDP-43相关神经变性的不同阶段中的小胶质细胞异质性。 目的2：研究小胶质细胞如何调节TDP-43神经变性中的皮层微电路。我们将 研究疾病进展和恢复期间不同皮质层中的小胶质细胞-神经元相互作用， rNLS 8小鼠，同时使用双光子和电子显微镜。我们还将确定小胶质细胞 TREM 2调节神经元回路，特别是在疾病进展的早期阶段，与TDP-43相关。 神经变性 目的3：操纵小胶质细胞作为TDP-43神经变性的潜在治疗靶点。我们将 在疾病的不同阶段使用化学遗传学精确控制小胶质细胞功能， 小胶质细胞的贡献。此外，我们将靶向TREM 2用于治疗TDP-43相关的神经变性。 我们的团队完全准备好开发成像小胶质细胞-神经元相互作用的新方法，并研究它们的相互作用。 在衰老和TDP-43相关的神经变性如ALS、FTLD和AD中的精确功能。这些创新 这些方法将为调节TDP-43相关的小胶质细胞机制提供变革性的见解。 神经退行性变和产生推定的治疗靶点，最终将帮助ALS，FTLD， AD和ADRD。

PROJECT SUMMARY Microglia, as the resident immune cells of the central nervous system, are key players in aging and neurodegenerative diseases, such as Alzheimer’s disease (AD) and AD-related dementias (ADRD). However, how microglia sense and regulate neurodegeneration remains largely unknown. TDP-43 is a DNA-binding protein that is a main component of the protein aggregates found in amyotrophic lateral sclerosis (ALS), frontotemporal lobar dementia (FTLD), and AD. We used inducible mouse model of TDP-43 translocation (rNLS8) that can mimic characteristic features of TDP-43 related neurodegeneration. Utilizing in vivo two- photon imaging, we have demonstrated that rNLS8 mice show neuronal hyperactivity in the cortex during disease progression, which is associated with unique rod-shaped microglia aligning along neuronal dendrites in the layer 4 cortex. Based on these exciting observations, we hypothesize that microglia have neuroprotective roles by regulating cortical microcircuit and attenuating neuronal hyperactivity in response to TDP-43 related neurodegeneration. We will test this hypothesis with the following three Aims: Aim 1: Determine the functional heterogeneity of microglial activation in TDP-43 neurodegeneration. We will use chronic, in vivo two-photon imaging to determine the spatiotemporal activation of microglia, including process dynamics, landscape changes, and proliferation. In addition, we will examine microglial Ca2+ activity using a newly developed microglial GCaMP7s mouse line and TREM2 dependence. The results from this aim will uncover microglial heterogeneity in different phases of TDP-43 related neurodegeneration. Aim 2: Investigate how microglia regulate cortical microcircuits in TDP-43 neurodegeneration. We will study microglia-neuron interactions in different cortical layers during disease progression and recovery in rNLS8 mice using simultaneous two-photon and electron microscopy. We will also determine how microglial TREM2 regulates neuronal circuits, particularly during the early phases of disease progress, in TDP-43 related neurodegeneration. Aim 3: Manipulate microglia as a potential therapeutic target in TDP-43 neurodegeneration. We will precisely control microglial function using chemogenetics in the different phases of disease and delineate microglial contributions. In addition, we will target TREM2 for treatment of TDP-43 related neurodegeneration. Our group is perfectly poised to exploit novel methods of imaging microglia-neuron interactions and study their precise function in aging and TDP-43 related neurodegeneration like ALS, FTLD and AD. These innovative approaches will provide transformative insights into microglial mechanisms of regulating TDP-43 related neurodegeneration and spawn putative therapeutic targets that will ultimately help patients with ALS, FTLD, AD, and ADRD.