Investigating selective regional and neuronal disease vulnerability in Spinocerebellar Ataxia Type 2

项目总结： 神经退行性疾病选择性地表现在特定的神经元群体和大脑区域，通过 我们还不了解的机制。脊髓小脑性共济失调2型(SCA2)是一种致命的遗传性疾病 ATXN2基因CAG核苷酸重复区域的扩张导致的神经退行性疾病， 导致一种具有神经毒性特性的功能增强的ATXN2蛋白。而ATXN2在整个 中枢神经系统，只有大脑结构和神经元的一部分容易受到严重萎缩和细胞死亡的影响。这个 小脑受到严重影响，导致失去自主运动、运动协调和语言能力。 SCA2患者的困难。在疾病进展过程中，有明显的小脑变性和 小脑浦肯野细胞的选择性丢失。小脑退行性变发生在前后部，以 抵抗神经变性的后部区域。基因和环境的多重侮辱也会导致 到小脑后部萎缩，这表明神经变性背后有一种保守的机制 渐变。到目前为止，可变小脑和浦肯野细胞背后的细胞和分子机制- SCA2中的特定漏洞尚未调查。我假设小脑的局部脆弱性 在SCA2中，神经保护通路在细胞应激反应中的差异表达是修饰的 和疾病。我将从以下几个具体目标来阐述这一假设。在目标1中，我将测试Hspb1、a 富含在小脑后部的基因，先前发现在其他小脑中具有神经保护作用 退行性疾病，可有助于保护小鼠SCA2模型中浦肯野细胞的丢失。如果是的话， 这将进一步支持退化模式背后的保守机制，并提出共同的 治疗途径。在目标2a中，我将通过使用SCA2模型来识别新的神经保护通路 小脑转录组时间和空间精细的高通量单细胞RNA测序 决议。在目标2B中，我将具体讨论SCA2中的区域浦肯野细胞脆弱性，方法是使用 细胞类型特异性核糖体图谱评估疾病易感性和疾病易感性之间的差异基因表达 有弹性的浦肯野细胞群。通过比较前部和后部的差异基因表达 小脑在Aim 2A和Aim 2B中，我将为未来确定疾病易感性的新基因修饰物 验证。这项研究将首次表征SCA2退变和疾病进展的单个- 单元时空分辨率。由于SCA2患者没有有效的治疗方法，因此理解 防止神经变性的因素和特定细胞类型对疾病病理的贡献将有所帮助 以便更好地为未来的治疗干预提供信息。

PROJECT SUMMARY: Neurodegenerative disorders manifest selectively in particular neuronal populations and brain regions, through mechanisms we do not yet understand. Spinocerebellar Ataxia Type 2 (SCA2) is a fatal, hereditary neurodegenerative disorder caused by expansions in the CAG nucleotide repeat region of the ATXN2 gene, causing a gain-of-function ATXN2 protein with neurotoxic properties. While ATXN2 is expressed throughout the CNS, only a subset of brain structures and neurons are vulnerable to gross atrophy and cell death. The cerebellum is highly affected, resulting in the loss of voluntary movement, motor coordination, and speech difficulties in SCA2 patients. Across disease progression, there is pronounced cerebellar degeneration and selective loss of cerebellar Purkinje cells. Cerebellar degeneration occurs anterior to posterior, with the most posterior regions resistant to neurodegeneration. Multiple genetic and environmental insults also cause anterior to posterior cerebellar atrophy, suggesting that a conserved mechanism underlies the neurodegeneration gradient. To date, the cellular and molecular mechanisms underlying the variable cerebellar and Purkinje cell- specific vulnerability in SCA2 have not been investigated. I hypothesize that regional cerebellar vulnerability in SCA2 is modified by differential expression of neuroprotective pathways in response to cellular stress and disease. I will address this hypothesis in the following specific aims. In Aim 1, I will test whether Hspb1, a gene enriched in the posterior cerebellum, and previously identified as neuroprotective in other cerebellar degenerative disorders, can contribute to the protection of Purkinje cell loss in a mouse model of SCA2. If so, this will further support a conserved mechanism underlying the degenerative pattern and suggest common therapeutic avenues. In Aim 2A, I will identify novel neuroprotective pathways in a SCA2 model with the use of high throughput single-cell RNA-sequencing of the cerebellar transcriptome at fine temporal and spatial resolution. In Aim 2B, I will specifically address regional Purkinje cell vulnerability in SCA2 through the use of cell-type-specific ribosomal profiling to assess differential gene expression between disease-vulnerable and - resilient Purkinje cell populations. By comparing differential gene expression between the anterior and posterior cerebellum in both Aim 2A and Aim 2B, I will identify novel genetic modifiers of disease vulnerability for future validation. This study will be the first to characterize SCA2 degeneration and disease progression at a single- cell spatiotemporal resolution. As there is no effective treatment available for SCA2 patients, understanding the factors that protect against neurodegeneration and cell-type-specific contributions to disease pathology will help to better inform future therapeutic interventions.