PrP-scrapie transport across intestinal & BBB

PrP-痒痒症跨肠道转运

• 批准号: 6951191
• 负责人: Neena Singh
• 金额: $ 26.78万
• 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/6951191
• 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BSE通过外周血静脉接种给实验动物传播，这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）外周血中朊病毒如何穿过内皮血脑屏障（BBB）。随着近100万头感染疯牛病的奶牛可能已经进入人类食物链，这些问题变得越来越重要。一个新出现的问题是慢性消耗病（CWD）的传播，这是美国某些地区鹿和麋鹿的朊病毒疾病，以及其传播给牲畜和人类的不确定性。尽管存在这些问题，但令人惊讶的是，人们对感染性朊病毒或PrP-scrapie（PrPsc）（一种27- 30 kDa的蛋白质）从肠道或外周血转运到中枢神经系统的机制知之甚少。 从我的实验室的初步数据表明，在散发性克雅氏病（sCJD）脑匀浆中的PrPsc与铁蛋白运输通过上皮细胞。当考虑在上下文中与额外的数据表明上调脑铁蛋白水平的sCJD的情况下，脑实质中的氧化还原活性铁的反应，这一观察提出了重要的问题。我们假设，运输PrPsc跨上皮和内皮细胞屏障是由蛋白质，如铁蛋白，具有明确的转胞途径，脑铁稳态的不平衡直接有助于某些朊病毒疾病的发病机制，并间接通过促进感染性通过铁蛋白。因此，该建议的中心目标是研究PrPs相关蛋白包括铁蛋白和转铁蛋白在促进其跨肠上皮和血脑屏障的运输中的作用，并评估氧化还原活性铁在朊病毒疾病发病机制中的作用。拟议的研究将在三个具体目标下进行。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跨人肠上皮细胞屏障和BBB的体外模型转运中的作用。在目标2中，将在表达人PrP的转基因小鼠中体内证实目标1中从体外模型获得的结果。在目标3中，将使用铁蛋白过表达和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。