Role of heparan sulfate in neural cell vulnerability to prions

项目概要/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增殖的机制。 易损性.硫酸乙酰肝素蛋白聚糖（HSPG）是促进淀粉样蛋白寡聚化的糖蛋白， β和朊病毒在体外和减缓清除淀粉样蛋白-β在阿尔茨海默病小鼠模型的大脑。 HSPGs通过其HS链与错误折叠的蛋白质相互作用，并促进其在永生化细胞中的内化。 神经细胞这种蛋白质聚集体的摄取受到HS长度和硫酸化水平的深刻影响， 重要的是，在细胞类型之间有很大差异。我们和其他人使用了高度硫酸化的HS-样糖共聚物 以测试HS在朊病毒的相互作用和体外复制中的关键作用。然而， 内源性HS及其在健康老年人和受疾病影响的大脑中的具体作用尚不清楚。我发现 表达较短HS链的小鼠表现出延长的存活时间和深刻改变朊病毒斑块分布 在大脑中，当感染了形成噬斑的朊病毒菌株时， 由朊病毒聚集形成的表型。在这里，我将定义HS分子，结合到生理 和错误折叠的朊病毒蛋白。我假设HS与 错误折叠的朊病毒是朊病毒疾病中选择性细胞脆弱性的主要决定因素。在 目的1，我将确定HS硫酸化在朊病毒复制中的作用i）在体外，使用从不同的 神经元群体，和ii）通过HS硫酸化缺陷的小鼠模型在体内。我将测量 HS硫酸化影响PrP细胞的向性和脑中的病变靶点，以及年龄如何影响HS 混合物.接下来，我将操纵不同神经元群体中的HS组成i）以测量 朊病毒菌株的选择性细胞摄取及其对HS的依赖程度（目的2），以及ii）测试新策略 基于使用HSPG模拟物作为促进朊病毒降解的媒介物， 溶酶体（Aim 3）。我希望能确定朊病毒选择性细胞脆弱性的分子机制 疾病和发现新的目标，为患者的神经保护疗法的合理设计与朊病毒 疾病由于朊病毒病和阿尔茨海默病的发病机制之间有许多共同点， 我计划最终将我的研究策略扩展到β淀粉样蛋白靶向细胞的研究。K99/R00 应用程序是一个理想的途径，以独立，是由一个优秀的导师组的支持， 顾问，高度创新技术的广泛培训，世界一流的科学环境， 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.