PrP-scrapie transport across intestinal & BBB

PrP-痒痒症跨肠道转运

• 批准号: 7119700
• 负责人: Neena Singh
• 金额: $ 26.15万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-20 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7119700
• 关键词: blood brain barrier; clinical research; communicable disease transmission; ferritin; food chain contamination; gastrointestinal epithelium; gene expression; gene mutation; genetic models; genetically modified animals; host organism interaction; human tissue; iron oxide; laboratory mouse; postmortem; prions; protein transport; scrapie; spongiform encephalopathy; tissue /cell culture; transferrin; virus genetics; virus infection mechanism; virus protein; virus replication

DESCRIPTION (provided by applicant): The transmission of variant Creutzfeldt-Jakob disease (vCJD) to humans from bovine-spongiform encephalopathy (BSE)-contaminated meat, and the transmission of BSE by intra-venous inoculation of peripheral blood to experimental animals raises two important questions: 1) how are prions from food transported across the intestinal epithelial barrier, and 2) how do prions in the peripheral blood cross the endothelial blood brain barrier (BBB). These questions have gained increasing importance with the realization that close to one million BSE infected cows may have entered the human food chain. An emerging concern is the spread of Chronic Wasting Disease (CWD), a prion disease of the deer and elk in certain parts of USA, and the uncertainties regarding its transmission to livestock and humans. Despite these concerns, surprisingly little is known about the mechanism(s) by which the infectious prion or PrP-scrapie (PrPsc), a protein of 27-30kDa, is transported from the intestine or peripheral blood to the central nervous system. Preliminary data from my laboratory demonstrate that PrPsc in sporadic CJD (sCJD) brain homogenates is transported across epithelial cells in association with ferritin. When considered in context with additional data indicating an upregulation of brain ferritin levels in response to redox active iron in the brain parenchyma of sCJD cases, this observation raises important questions. We hypothesize that the transport of PrPsc across epithelial and endothelial cell barriers is facilitated by proteins like ferritin that have a defined transcytotic route, and that imbalance of brain iron homeostasis contributes directly to the pathogenesis of certain prion disorders, and indirectly by promoting infectivity through ferritin. Thus, the central goal of this proposal is to investigate the role of PrPs-associated proteins including ferritin and transferrin in facilitating its transport across the intestinal epithelium and the BBB, and to evaluate the role of redox active iron in the pathogenesis of prion disorders. The proposed studies will be carried out in three specific aims. In aim 1, the role of ferritin, transferrin, and other PrPsc-associated proteins in the transport of PrPsc across in vitro models of human intestinal epithelial cell barrier and the BBB will be evaluated. In aim 2, the results obtained from in vitro models in aim 1 will be confirmed in vivo in transgenic mice expressing human PrP. In aim 3, the role of redox active iron in the pathogenesis of priori disorders will be investigated using ferritin over-expressing and H-ferritin deletion transgenic mice. These studies will help in evaluating the risk of human population to BSE, vCJD, and CWD infection, and help in understanding the mechanism of prion disease pathogenesis.

描述（申请人提供）：变异型克雅氏病（vCJD）通过牛海绵状脑病（BSE）污染的肉类传播给人类，以及通过外周血静脉内接种向实验动物传播疯牛病，提出了两个重要问题：1）食物中的朊病毒如何穿过肠上皮屏障，2）如何 外周血中的朊病毒可穿过内皮血脑屏障（BBB）。随着人们认识到近一百万头感染 BSE 的奶牛可能已进入人类食物链，这些问题变得越来越重要。一个新出现的问题是慢性消耗性疾病（CWD）的传播，这是美国某些地区鹿和麋鹿的一种朊病毒病，以及其传播给牲畜和人类的不确定性。尽管存在这些担忧，但令人惊讶的是，人们对传染性朊病毒或 PrP-scrapie (PrPsc)（一种 27-30kDa 的蛋白质）从肠道或外周血转运至中枢神经系统的机制知之甚少。 我实验室的初步数据表明，散发性克雅氏病 (sCJD) 脑匀浆中的 PrPsc 与铁蛋白一起跨上皮细胞转运。当结合其他数据考虑时，这些数据表明 sCJD 病例脑实质中氧化还原活性铁导致脑铁蛋白水平上调，这一观察结果提出了重要的问题。我们假设铁蛋白等具有明确转胞吞途径的蛋白质促进 PrPsc 穿过上皮细胞和内皮细胞屏障的转运，并且脑铁稳态失衡直接导致某些朊病毒疾病的发病机制，并通过铁蛋白间接促进感染性。因此，该提案的中心目标是研究 PrPs 相关蛋白（包括铁蛋白和转铁蛋白）在促进其跨肠上皮和 BBB 运输方面的作用，并评估氧化还原活性铁在朊病毒疾病发病机制中的作用。拟议的研究将针对三个具体目标进行。在目标 1 中，将评估铁蛋白、转铁蛋白和其他 PrPsc 相关蛋白在 PrPsc 穿过人肠上皮细胞屏障和 BBB 体外模型转运中的作用。在目标 2 中，从目标 1 的体外模型获得的结果将在表达人 PrP 的转基因小鼠体内得到证实。在目标 3 中，将使用铁蛋白过度表达和 H-铁蛋白缺失转基因小鼠研究氧化还原活性铁在先天性疾病发病机制中的作用。这些研究将有助于评估人群感染 BSE、vCJD 和 CWD 的风险，并有助于了解朊病毒病的发病机制。