Role of heparan sulfate in neural cell vulnerability to prions

项目摘要/摘要 神经退行性疾病中一个尚未解决的主要问题是驱动选择性细胞的机制 脆弱性。硫酸乙酰肝素蛋白多糖(HSPGs)是一种促进淀粉样蛋白齐聚的糖蛋白。 β和普鲁恩在体外，并减缓淀粉样蛋白-β在阿尔茨海默病小鼠模型脑中的清除。 HSPG通过HS链与错误折叠的蛋白质相互作用，促进其在永生化中的内化 神经细胞。这种蛋白质的聚集摄取受到HS的硫酸盐化长度和水平的深刻影响， 重要的是，不同类型的细胞有很大不同。我们和其他人已经使用了高度硫酸盐化的HS类糖共聚物 测试HS在Pron相互作用和体外复制中的关键作用。然而，组成的 内源性HS及其在健康、老年和疾病影响的脑中的具体作用尚不清楚。我发现 表达较短HS链的小鼠存活时间延长，Pron斑块分布发生深刻变化 在大脑中感染了一种形成空斑的普恩病毒株，但在普恩病毒病中没有表现出任何变化 由聚集体形成的普恩引起的表型。在这里，我将定义结合到生理上的HS分子 以及在不同的神经元群体中错误折叠的Prion蛋白。我假设HS和Hs的相互作用 Pron的错误折叠是Pron病选择性细胞脆弱性的主要决定因素。在……里面 目的1)利用从DISTINCT中分离到的HS，确定HS硫化在体外PrP复制中的作用 以及ii)在体内，通过HS硫酸盐化缺陷的小鼠模型。我将衡量这种变化如何 在HS中，硫酸盐化影响大脑中PrP细胞的趋向性和损伤靶点，以及年龄如何影响HS 组成。接下来，我将操纵不同神经元群体中的HS成分i)以测量 Pron菌株的选择性细胞摄取及其对HS的依赖程度(目标2)，和ii)测试新策略 基于使用HSPG模拟物作为载体来促进PrN降解的基础上阻止Prion的进展 溶酶体(目标3)。我希望能确定普恩病毒选择性细胞脆弱性背后的分子机制。 并为合理设计普恩患者的神经保护治疗寻找新的靶点 疾病。由于Prion病和阿尔茨海默病的发病机制有许多共同之处，我 计划最终将我的研究策略扩展到通过淀粉样蛋白β进行细胞靶向的研究。这是K99/R00 应用程序是一条理想的独立之路，它得到了一群优秀的导师和 顾问，在高度创新技术方面的广泛培训，世界级的科学环境，以及清晰的 部门承诺。

PROJECT SUMMARY / ABSTRACT A major unresolved question in neurodegenerative disease is the mechanisms that drive selective cell vulnerability. Heparan sulfate proteoglycans (HSPGs) are glycoproteins that promote oligomerization of amyloid- β and prions in vitro and slow the clearance of amyloid-β in the brain of an Alzheimer’s disease mouse model. HSPGs interact with misfolded proteins through their HS chains and promote their internalization in immortalized neural cells. This protein aggregate uptake is profoundly impacted by the HS length and level of sulfation which, importantly, broadly differ between cell types. We and others have used highly sulfated HS-like glycopolymers to test the crucial role of HS in the interaction and in vitro replication of prions. However, the composition of endogenous HS and their specific roles in healthy aged and disease-affected brain are unknown. I found that mice expressing shorter HS chains showed prolonged survival and profoundly altered prion plaque distribution in brain when infected with a plaque-forming prion strain, but did not show any change in the prion disease phenotype caused by aggregate-forming prions. Here I will define the HS molecules that bind to physiological and misfolded prion protein in different neuronal populations. I hypothesize that the interaction of HS with misfolded prions is a major determinant underlying the selective cell vulnerability in prion disease. In Aim 1, I will determine the role of HS sulfation in the prion replication i) in vitro, using HS isolated from distinct neuronal populations, and ii) in vivo, by mouse models deficient in HS sulfation. I will measure how the variation in the HS sulfation impacts the PrP cell tropism and lesion targets in the brain, and how age affects HS composition. I will next manipulate the HS composition in different neuronal populations i) to measure the selective cell uptake of prions strains and their degree of dependence on HS (Aim 2), and ii) to test a new strategy to block prion progression based on using HSPG mimetics as vehicles to promote prion degradation in lysosomes (Aim 3). I expect to define the molecular mechanisms underlying selective cell vulnerability in prion disease and to discover new targets for the rational design of neuroprotective therapies for patients with prion disease. Due to the many commonalities between the pathogenesis of prion disease and Alzheimer’s disease, I plan to ultimately extend my research strategy to the study of cell targeting by amyloid-β. This K99/R00 application is an ideal pathway to independence that is supported by an outstanding group of mentors and advisors, extensive training in highly innovative techniques, a world-class scientific environment, and clear departmental commitment.