The role of prion protein conformers in prion disease

描述(申请人提供)：Prion蛋白(PrP)是脊椎动物的一种保守的糖蛋白，与一组海绵状神经退行性疾病有关，统称为Prion疾病，其中一些疾病在全球范围内构成重大的、目前未得到满足的公共健康危害。因此，更好地了解PrP在PrP疾病发病机制中的作用是至关重要的。 Pron疾病包括一组重叠的疾病，这些疾病在病因学上是否遗传(遗传)、传染性(可传播)或看似自发(散发性)的程度各不相同。这些不同的表现表明PrP和其他涉及神经系统发育、维持或功能的基因之间的重要关系仍有待阐明。因此，对Pron病发病机制的研究可能是对神经生物学其他方面目前难以解决的问题的一个强有力的探索。 PRP也因其非凡的生物发生而引起人们的兴趣。最初均一的新生PrP链被合成为独特的形式，称为构象，这些构象在初级氨基酸序列中相同，但在跨膜拓扑和固有折叠方面都不同。一种复杂的机制与两种PrP构象的发生有关，被称为SecPrP和CtmPrP，并且信号序列在指导这一过程中具有令人惊讶的作用。 独立的研究路线汇聚在一起，证明PrP生物发生的不寻常特征是其在遗传性PrP疾病中作用的核心。在过去4年的研究中，在本基金的支持下，在理解PrP构象及其在PrP疾病发病机制中的作用方面取得了重大进展。特别是，已经确定CtmPrP在传染性和遗传性Pron疾病中也起着关键作用，并通过触发一条凋亡通路而导致神经变性。此外，包括细胞培养和TG小鼠在内的强大的模型系统已经被开发出来，并开始用于剖析涉及CtmPrP的疾病相关的凋亡途径。 在一定程度上，由于目前赠款期间的进展，出现了关于CtmPrP和其他PrP一致性的重要新问题。在这份续签申请中，我们建议在以前研究的基础上，利用我们在过去四年中开发的各种工具和试剂，研究疾病中的PrP构象。基于我们最近展示的它们在检测单个构象方面的效用，我们还将产生针对构象特异性的mAbs，用于免疫细胞化学的优化。利用这些工具，我们将：i)证实在其他Prion病模型系统中的CTM指数，并探索在触发或抑制细胞凋亡方面这一主题的变化的可能性；ii)阐明CtmPrP触发细胞凋亡的精确相互作用；iii)解决PrP构象的翻译后修饰在Prion病中的作用，包括作为构象生产/输出调节因子的信号肽的假定作用；iv)尝试检测NtmPrP并阐明其在Prion病中的作用(如果有的话)，以及v)确定PrPSc似乎通过其触发CtmPrP产生的信号通路(S)。 通过这些研究，正在进行的关于PrP介导的神经退行性变的卓有成效的研究将得到延伸，提供关于CtmPrP、SecPrP和NtmPrP在PrP疾病中的作用的更高程度的清晰度和精确度。此外，还将探索有关PrP构象调控的令人兴奋的新方向，为基于增强或抑制PrP构象的产生和成熟的潜在治疗方法的开发奠定基础。

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.