Absorption, Metabolism and Biodistribution of Prions after Oral Ingestion

描述（由申请人提供）：朊病毒疾病是一组影响动物和人类的致命性神经退行性疾病。中心致病事件是宿主编码的朊病毒蛋白（PrPC）转化为错误折叠的同种型（PrPSc）。PrPSc似乎是感染因子（称为朊病毒）的主要或唯一组分，其具有在不存在核酸的情况下传播疾病的惊人能力。朊病毒可以通过各种途径感染个体，包括口服，进入体内并在各种组织中沉默复制很长一段时间，然后在大脑中引起毁灭性疾病。我们的工作假设是，几个生物过程，包括通过肠道屏障的吸收，组织分布，代谢，清除和外周朊病毒复制控制PrPSc在体内的命运，并决定是否最初的口腔感染将发展成全面的疾病。该项目的主要目标是以详细和定量的方式研究朊病毒在口服暴露后的初始命运，包括估计肠道代谢、肠道吸收、排泄、全身组织分布和脑摄取。此外，我们将调查胃肠道网站负责朊病毒的吸收和PrPSc穿透肠屏障的机制。我们还将研究朊病毒菌株对各种动物物种中这些参数的影响，包括大型动物（鹿）中的天然朊病毒宿主。此外，我们将研究PrPC表达的作用和PrPSc与土壤颗粒的相互作用在其体内摄入后的命运。最后，我们将研究朊病毒在整个身体的动态分布期间，从初始感染到临床疾病的表现。这项研究中产生的结果将大大增加我们对朊病毒命运控制机制和PrPSc从口腔到大脑运输途径的理解。这些数据将为评估朊病毒在不同组织中污染的风险提供重要信息。更重要的是，该项目的发现将为开发治疗策略开辟新的途径，例如防止朊病毒在肠道中吸收，减少大脑的摄取或增加朊病毒的代谢和消除。

DESCRIPTION (provided by applicant): Prion diseases are a group of fatal neurodegenerative disorders affecting animals and humans. The central pathogenic event is the conversion of the host-encoded prion protein (PrPC) into a misfolded isoform (PrPSc). PrPSc appears to be the main or sole component of the infectious agent (termed prion) that has the surprising ability to propagate the disease in the absence of nucleic acid. Prions can infect an individual by various routes, including oral ingestion, enter into the body and remain silently replicating in various tissues for a long time before causing a devastating disease in the brain. Our working hypothesis is that several biological processes, including absorption across intestinal barrier, tissue distribution, metabolism, clearance and peripheral prion replication control the fate of PrPSc in the body and determine whether or not the initial oral infection will progress into full-blown disease. The main goal of this project is to study in a detailed and quantitative manner the initial fate of prions upon oral exposure, including the estimation of gut metabolism, intestinal absorption, excretion, whole body tissue distribution, and brain uptake. In addition, we will investigate the gastrointestinal site responsible for prion absorption and the mechanism by which PrPSc penetrates the intestinal barrier. We will also study the effect of prion strains on these parameters in various animal species, including a natural prion host in large animals (cervids). Furthermore, we will study the role of PrPC expression and the interaction of PrPSc with soil particles in its fate upon ingestion in vivo. Finally, we will investigate the dynamic distribution of prions across the entire body during the period from initia infection to the manifestation of the clinical disease. The findings generated in this study will substantially increase our understanding of the mechanism controlling the fate of prions and the pathways implicated in the transport of PrPSc from the mouth to the brain. This data will provide important information to assess the risk of prion contamination in diverse tissues. More importantly, the findings generated in this project will open novel avenues to develop therapeutic strategies aiming for example to prevent prions to be absorbed in the intestine, to decrease uptake into the brain or to increase prion metabolism and elimination.