How substrate dosage drives prion disease kinetics

项目总结 Pron病是一种独特的快速、普遍致命的进行性神经退行性疾病，在人类和其他 哺乳动物。它起源于一种单一的蛋白质，即天然的Prion蛋白(PrP)，它能够翻译后 错误地折叠成一个自我模板和致命的“普里恩”。概念的遗传学和药理学证据 越来越多地将PrP剂量确定为了解并最终拦截这种致病机制的关键 卡斯卡德。在PrP基因水平改变的小鼠中，PrP水平较低会导致PrP水平较低的小鼠在PrP基因改变后存活时间更长 感染，而过量的PrP会加速疾病。降低PRP的反义寡核苷酸(ASO)现在显示 作为一种潜在的治疗策略。然而，有效的执行将取决于更深层次的 了解PrP水平如何控制PrP成核、复制和神经毒性的速率，以及如何 这种控制跨越了疾病的时间点、物种和品系。尽管几乎所有的人类普恩病毒病 起源于大脑，降低PrP的干预措施尚未在自发的情况下进行测试，而不是 接种过的普恩病毒模型。同时，50%的遗传性PrP减少所传达的保护程度可以 在不同的模型系统之间有所不同；减慢的Pron复制和减慢的神经毒性对 观察到的在不同物种中的生存益处，以及Pron菌株仍有待解开。最后，降低PrP 必须在患者来源的人类普恩病毒的背景下进行研究，以评估上述知识如何外推到 公共卫生利益的压力。我们将通过评估以下内容来填补这些空白。1)自发运动的动力学 普里恩形成。使用一种新的自发性Pron病小鼠模型，我们将跟踪自发的 通过对神经元损伤和普恩病毒种子活性的一系列分子测量来研究疾病过程。 通过在不同的时间点给予PrP降低工具化合物，我们将解开PrP是如何 剂量调节Pron的形成、扩增、神经毒性和症状进展。2)快速和 慢病毒亚型与PrP剂量的关系。使用新设计的PrP基因敲除仓鼠和大鼠 模型中，我们将描述病理性生物标记物相对于疾病的发病和晚期的上升的动力学。 典型快速(仓鼠)和进展较慢的PrP表达水平对疾病的影响 (大鼠)Pron疾病系统。3)PrP降低对人PrP的影响。使用了一系列的小说 已经显示了以六种不同剂量水平表达人PrP的人源化小鼠系 易受多种临床上相关的人类普恩病毒株的影响，我们将表征发病时间、症状 起病和绝症。PRP水平也将通过基因操作终生变化 如通过出生后，精确定时的干预，降低PrP的工具化合物。这些加在一起， 研究将阐明PrP在一系列Prion疾病范例中对疾病动力学的控制，而 为指导未来PrP降压疗法的发展奠定科学基础。

PROJECT SUMMARY Prion disease is a uniquely rapid, universally fatal progressive neurodegenerative disease of humans and other mammals. It arises from a single protein, the native prion protein (PrP), which is capable of post-translationally misfolding into a self-templating and deadly “prion.” Genetic and pharmacological proofs of concept increasingly identify PrP dosage as the key to understanding, and ultimately intercepting this pathogenic cascade. In mice with genetically altered PrP levels, lower PrP levels lead to longer survival following prion infection, while excess PrP hastens disease. PrP-lowering antisense oligonucleotides (ASOs) now show promise as a potential therapeutic strategy. However, effective implementation will hinge on a deeper understanding of how PrP level controls the rates of prion nucleation, replication and neurotoxicity, and how this control translates across disease timepoints, species and strains. Though almost all human prion disease originates in the brain, PrP-lowering interventions have not yet been tested in spontaneous, rather than inoculated, prion models. Meanwhile, the magnitude of protection conveyed by 50% genetic PrP reduction can vary between model systems; the relative contributions of slowed prion replication and slowed neurotoxicity to observed survival benefit in different species and prion strains remain to be disentangled. Finally, PrP lowering must be studied in the context of patient-derived human prions, to assess how above learnings extrapolate to strains of public health interest. We will fill these gaps by assessing the following. 1) Kinetics of spontaneous prion formation. Using a new mouse model of spontaneous prion disease, we will track the spontaneously disease process through serial molecular measurements of neuronal damage and prion seeding activity. Through PrP-lowering tool compounds administered at different timepoints, we will disentangle how PrP dosage modulates prion formation, amplification, neurotoxicity and symptomatic progression. 2) Rapid and slow prion subtypes as a function of PrP dosage. Using newly engineered PrP knockout hamster and rat models, we will characterize the kinetics of pathological biomarker rise relative to disease onset and terminal illness as a function of PrP expression level in both canonically rapid (hamster) and more slowly progressive (rat) prion disease systems. 3) Impact of PrP lowering on human prions. Using a series of novel “humanized” mouse lines expressing human PrP at six different dosage levels, that have been shown susceptible to multiple clinically relevant human prion strains, we will characterize time to pathology, symptom onset, and terminal illness. PrP level will be varied on a lifelong basis through genetically manipulation, as well as through postnatal, precisely timed intervention with PrP-lowering tool compounds. Taken together, these studies will illuminate PrP’s control of disease kinetics across a spectrum of prion disease paradigms, while building a scientific foundation to guide future development of PrP-lowering therapeutics.