Concordance of TDP-43 Inclusions with Cortical Atrophy and Clinical Phenotype

项目摘要 错误折叠的蛋白质以异常包涵体的形式聚集和繁殖是 许多神经退行性疾病。大多数患有额颞叶变性(FTLD)的大脑 以反式激活反应元件DNA结合蛋白-43错误定位和聚集为特征 (TDP-43)转变为不溶性包裹体。鉴于TDP-43是最近发现的病理性疾病之一 关于沉淀，本项目第一周期的目标是探索TDP-43夹杂物之间的关系， FTLD和条件转基因小鼠的细胞变化、皮质萎缩和疾病表型 野生型人(H)TDP-43在前脑的表达模型。我们观察到TDP-43的密度 皮质灰质和白质中的包涵体、神经元萎缩和激活的小胶质细胞密度 与皮质萎缩和疾病表型的模式一致，TDP-43包涵体可能扩散 跨突触的。在TDP-43转基因小鼠中，我们证实了区域性选择性皮质萎缩，并且 进行性TDP-43积聚和包涵体形成、胶质细胞增生、细胞凋亡和行为改变 与FTLD的病理和行为改变相一致。重要的是，被激活的密度 小胶质细胞与皮质萎缩和疾病表型的关系最密切和最一致 FTLD。这个项目的第二个周期建立在第一个周期的观察基础上，并将重点放在小胶质细胞的作用上 /免疫激活，包括在疾病传播时对突触进行修剪。我们将进行一项全面调查 FTLD和hTDP转基因小鼠脑内小胶质细胞/免疫基因和蛋白表达的变化 探讨FTLD中突触和突触蛋白的变化及小胶质细胞介导的修剪的潜在作用 突触丢失，并将研究小胶质细胞产生的外体在TDP-43病理传播中的作用 在小鼠模型中。我们建议将这项调查建立在严格的量化方法基础上，包括 一组独特的尸检标本的无偏体视学定量和RNA测序(RNAseq) 具有广泛的临床和病理信息，并在小鼠模型中概括了 人类疾病。拟议研究的具体目标将检验以下假设：目标1.FTLD-- TDP和hTDP-43转基因小鼠脑内小胶质细胞将出现区域性选择性改变 转录组和相关的免疫蛋白。目的2.FTLD-TDP和hTDP-43转基因小鼠将显示 突触的大量、早期和区域性丢失，部分原因是突触修剪异常 小胶质细胞。目的3.hTDP-43转基因小鼠将随着时间的推移表现出TDP-43病理的跨突触传播 海马体和小胶质细胞衍生的外切体促进了这种在海马体和大脑皮层中的扩散。 这项拟议的研究将产生大量关于突触状态和潜在的反式作用的信息。 TDP病理的突触扩散以及小胶质细胞在这些过程和免疫中的作用 改装。这些发现有可能阐明可以作为治疗靶点的途径。

Project Summary Aggregation and propagation of misfolded proteins in the form of abnormal inclusions is a common feature of numerous neurodegenerative diseases. A majority of brains with frontotemporal lobar degeneration (FTLD) are characterized by mislocalization and aggregation of transactivation response element DNA binding protein-43 (TDP-43) into insoluble inclusions. Given that TDP-43 is among the most recently identified pathologic precipitates, the goal of Cycle 1 of this project was to explore the relationship between TDP-43 inclusions, cellular alterations, cortical atrophy and disease phenotype in FTLD and in a conditionally transgenic mouse model expressing wild-type human (h) TDP-43 in the forebrain. We observed that density of TDP-43 inclusions, neuronal shrinkage, and density of activated microglia in cortical gray and white matter are concordant with patterns of cortical atrophy and disease phenotype and that TDP-43 inclusions may spread trans-synaptically. In TDP-43 transgenic mice, we confirmed regionally selective cortical atrophy, and progressive TDP-43 accumulation and inclusion formation, gliosis, apoptosis and behavioral alterations consistent with the pathologic and behavioral alterations in FTLD. Importantly, the density of activated microglia displayed the closest and most consistent relationship with cortical atrophy and disease phenotype in FTLD. Cycle 2 of this project builds upon the observations during Cycle 1 and will focus on the role of microglia / immune activation, including synaptic pruning as disease spreads. We will conduct a comprehensive survey of microglia / immune gene and protein expression changes in brains of FTLD and hTDP transgenic mice, will explore alterations in synapses and synaptic proteins in FTLD and potential role of microglia mediated pruning in synaptic loss, and will investigate the role of microglia generated exosomes in spread of TDP-43 pathology in the mouse model. We propose to base this investigation on rigorous quantitative methods, including unbiased stereological quantification and RNA sequencing (RNAseq) in a unique set of autopsy specimens with extensive clinical and pathological information and in a mouse model which recapitulates features of human disease. The specific aims of the proposed research will test the following hypotheses: Aim 1. FTLD- TDP and hTDP-43 transgenic mouse brains will display regionally selective alterations in microglia transcriptome and associated immune proteins. Aim 2. FTLD-TDP and hTDP-43 transgenic mice will display substantial, early and regionally specific loss of synapses that is due in part to abnormal synaptic pruning by microglia. Aim 3. hTDP-43 transgenic mice will display trans-synaptic spread of TDP-43 pathology over time in the hippocampus and microglia derived exosomes facilitate this spread in the hippocampus and across cortex. The proposed research will generate a great deal of information on the status of synapses and potential trans- synaptic spread of TDP pathology as well as the role of microglia in these processes and in immune alterations. The findings have the potential to illuminate pathways that can serve as therapeutic targets.