Prion protein conformers in prion disease

朊病毒病中的朊病毒蛋白构象异构体

• 批准号: 6611752
• 负责人: VISHWANATH R LINGAPPA
• 金额: $ 35.82万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-04-01 至 2007-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6611752
• 关键词: BCL2 gene /protein; Bax gene /protein; apoptosis; biological signal transduction; clinical research; crosslink; gene expression; gene mutation; gene targeting; genetically modified animals; immunocytochemistry; laboratory mouse; monoclonal antibody; neural degeneration; pathologic process; posttranslational modifications; prions; protein biosynthesis; protein protein interaction; protein signal sequence; spongiform encephalopathy; tissue /cell culture; transfection

DESCRIPTION (provided by applicant): The prion protein (PrP) is a conserved glycoprotein of vertebrates that is involved in a group of spongiform neurodegenerative disorders, collectively termed prion diseases, some of which pose a substantial and currently unmet public health hazard around the globe. Hence a better understanding of PrP's role in prion disease pathogenesis is paramount. Prion diseases include overlapping sets of disorders that vary as to whether, and to what degree, they are inherited (genetic), infectious (transmissible), or seemingly spontaneous (sporadic) in etiology. These diverse manifestations suggest that important relationships between PrP and other genes involved in the development, maintenance, or function of the nervous system remain to be elucidated. Thus, the study of prion disease pathogenesis may be a powerful probe of otherwise currently intractable dimensions of neurobiology. PrP has also been of interest because of its remarkable biogenesis. Initially homogeneous nascent PrP chains are synthesized as distinctive forms, termed conformers that are identical in primary amino acid sequence but different in both transmembrane topology and intrinsic folding. A complex machinery has been implicated in the genesis of two of the PrP conformers, termed SecPrP and CtmPrP, and a surprising role for signal sequences in directing this process has been identified. Independent lines of inquiry converged with the demonstration that the unusual features of PrP biogenesis are central to its role in genetic prion disease. From studies carried out over the past 4 years with support of the present grant, major progress has been made in understanding the conformer termed PrP, and its role in prion disease pathogenesis. In particular it has been established that CtmPrP also plays a crucial role in infectious as well as genetic prion disease and brings about neurodegeneration by triggering a pathway of apoptosis. Furthermore, powerful model systems, including cell culture and Tg mice that reproduce key features of prion disorders, have been developed and are beginning to be used for dissection of the disease-associated apoptotic pathway involving CtmPrP. In part as a result of the progress in the present grant period, important new questions regarding CtmPrP and other PrP conformers have emerged. In this renewal application we propose to build on our previous studies, utilizing the full range of tools and reagents that we have developed over the past four years, for the study of PrP conformers in disease. Based on our recent demonstration of their utility in detection of individual conformers, we will also generate conformer-specific mAbs optimized for immunocytochemistry. Using these tools we will: i) corroborate the Ctm index in other model systems of prion disease and explore the possibility of variations on this theme in triggering or suppressing apoptosis; ii) elucidate the precise interactions by which CtmPrP triggers apoptosis; iii) address the role of posttranslational modifications of PrP conformers in prion disease, including the putative role of cleavage of the signal peptide as a regulator of conformer production/export, iv) attempt to detect NtmPrP and explicate its role, if any, in prion disease, and v) identify the signaling pathway(s) by which PrPSc appears to trigger CtmPrP production. Through these studies, an ongoing fruitful line of investigation with regards to PrP-mediated neurodegeneration will be extended, providing a greater degree of clarity and precision with regards to the role of CtmPrP, SecPrP, and NtmPrP in prion disease. In addition, exciting new directions regarding the regulation of PrP conformers will be explored, setting the stage for the development of potential therapeutic modalities based on enhanced or suppressed production and maturation of PrP conformers.

描述（由申请人提供）：朊病毒蛋白（PrP）是脊椎动物的一种保守糖蛋白，与一组海绵状神经退行性疾病（统称为朊病毒疾病）有关，其中一些疾病对地球仪周围的公众健康造成了重大且目前尚未得到满足的危害。因此，更好地了解PrP在朊病毒疾病发病机制中的作用至关重要。 朊病毒疾病包括重叠的疾病集合，这些疾病在病因学上是否是遗传性的（遗传）、感染性的（传染性的）或看似自发的（散发性的）以及在何种程度上是不同的。这些不同的表现表明，PrP和其他基因参与神经系统的发育，维护或功能之间的重要关系仍有待阐明。因此，朊病毒病发病机制的研究可能是一个强有力的探针，否则目前棘手的神经生物学方面。 PrP也因其显著的生物起源而受到关注。最初同质的新生PrP链被合成为独特的形式，称为构象异构体，其在一级氨基酸序列中相同，但在跨膜拓扑结构和内在折叠中不同。一个复杂的机器已牵连在成因的两个PrP构象，称为SecPrP和CtmPrP，和一个令人惊讶的作用，信号序列在指导这一进程已被确定。 独立的调查路线与证明PrP生物发生的不寻常特征是其在遗传性朊病毒疾病中的作用的核心相融合。从过去4年来在本基金支持下进行的研究来看，在理解称为PrP的构象体及其在朊病毒疾病发病机制中的作用方面取得了重大进展。特别地，已经确定CtmPrP在传染性以及遗传性朊病毒疾病中也起关键作用，并且通过触发细胞凋亡途径而引起神经变性。此外，强大的模型系统，包括细胞培养和Tg小鼠复制朊病毒疾病的关键特征，已经开发出来，并开始用于解剖的疾病相关的凋亡途径，涉及CtmPrP。 部分由于在本补助期内的进展，出现了关于CtmPrP和其他PrP构象的重要新问题。在此更新申请中，我们建议建立在我们以前的研究基础上，利用我们在过去四年中开发的全系列工具和试剂，用于疾病中PrP构象的研究。基于我们最近证明它们在检测单个构象异构体中的实用性，我们还将产生针对免疫细胞化学优化的构象异构体特异性mAb。使用这些工具，我们将：i）证实朊病毒疾病的其他模型系统中的Ctm指数，并探索在触发或抑制细胞凋亡中该主题的变化的可能性; iii）阐明PrP构象异构体的翻译后修饰在朊病毒疾病中的作用，包括作为构象异构体产生/输出的调节剂的信号肽的切割的推定作用，iv）尝试检测NtmPrP并阐明其在朊病毒疾病中的作用（如果有的话），和v）鉴定PrPSc似乎通过其触发CtmPrP产生的信号传导途径。 通过这些研究，一个正在进行的富有成效的线调查方面的朊蛋白介导的神经变性将得到扩展，提供更大程度的清晰度和精确度方面的作用，CtmPrP，SecPrP和NtmPrP朊病毒疾病。此外，还将探索有关PrP构象异构体调节的令人兴奋的新方向，为基于增强或抑制PrP构象异构体的产生和成熟的潜在治疗方式的开发奠定基础。