TSE Prion Cell Biology

传染性海绵状脑病（Transmissible spongiform encephalopathies，TSE）是一组影响多种哺乳动物的神经退行性疾病，包括绵羊和山羊（羊瘙痒病）、鹿属（cervid spp.）（慢性消耗性疾病）和人类（克雅氏病）。 我们的研究集中在朊病毒蛋白（PrP），因为这种蛋白在控制TSE发病机制的许多方面，如疾病易感性和种间传播中起着关键作用。 TSE疾病的中心事件涉及正常宿主细胞朊病毒蛋白（PrPC）转化为部分蛋白酶抗性、聚集的疾病相关同种型（PrPSc）。 TSE引起的病理学改变通常与PrP-res沉积有关，但神经退行性变的机制尚不清楚。 感染因子的性质，称为朊病毒，仍然不确定，但被认为主要由错误折叠的PrP组成，可能与另一种宿主辅助分子复合。 PrPC是糖基磷脂酰肌醇（GPI）锚定的糖蛋白，并且体内产生的大多数PrPSc含有该GPI锚。 膜协会的正常和疾病相关的PrP亚型可能会影响朊病毒疾病和PrPC功能的许多特点。 我们的工作重点是阐明摄取，复制和传播的朊病毒的机制，除了确定哺乳动物朊病毒的生化组成。 2015年，我们继续对源自纯化重组PrP的新型TSE试剂合成菌株进行表征，并通过使用原代神经元的新型培养系统中的成像研究进一步研究了PrPSc的摄取、繁殖和细胞间扩散机制。 对合成TSE菌株的实验证实，我们已经分离出一种独特的合成TSE朊病毒，其繁殖完全依赖于GPI-无锚PrPC。 我们还表征了在表达GPI无锚PrPC的宿主中繁殖期间发生的TSE试剂的应变依赖性变化。

Transmissible spongiform encephalopathies (TSEs) are a group of neurodegenerative diseases affecting a wide variety of mammals including sheep and goats (scrapie), cervid spp. (chronic wasting disease), and humans (Creutzfeldt-Jakob disease). Our studies are focused on the prion protein (PrP) due to the critical role of this protein in controlling many aspects of TSE pathogenesis such as susceptibility to disease and interspecies transmission. A central event in TSE disease involves the conversion of the normal host cellular prion protein (PrPC) to a partially protease-resistant, aggregated, disease-associated isoform (PrPSc). TSE-induced pathology is usually associated with PrP-res deposition, but the mechanism of neurodegeneration is not understood. The nature of the infectious agent, called a prion, remains uncertain but is thought to be composed primarily of misfolded PrP, perhaps in complex with another host accessory molecule(s). PrPC is a glycosylphosphatidylinositol (GPI)-anchored glycoprotein, and the majority of PrPSc produced in vivo contains this GPI anchor. Membrane association of both normal and disease-associated PrP isoforms may influence many features of prion disease and PrPC function. Our work is focused on elucidating mechanisms of uptake, replication, and spread of prions, in addition to determining the biochemical composition of mammalian prions. In 2015, we have continued the characterization of novel synthetic strains of TSE agents that originate from purified recombinant PrP and further investigated mechanisms of uptake, propagation, and intercellular spread of PrPSc via imaging studies in novel culture systems using primary neurons. Experiments on synthetic TSE strains confirm we have isolated a unique synthetic TSE prion completely dependent on GPI-anchorless PrPC for propagation. We have also characterized strain-dependent changes to TSE agents that occur during propagation in hosts expressing GPI-anchorless PrPC.