TSE Prion Cell Biology

传染性海绵状脑病(TSEs)是一组影响多种哺乳动物的神经退行性疾病，包括绵羊、山羊(瘙痒病)、鹿。(慢性消耗性疾病)和人类(克雅氏病)。我们的研究主要集中在Prion蛋白(PrP)上，因为该蛋白在控制TSE发病的许多方面起着关键作用，如疾病易感性和物种间传播。TSE病的一个中心事件涉及将正常宿主细胞内的Prion蛋白(PrPC)转换为部分抗蛋白酶的、聚集的、疾病相关的亚型(PrPSc)。TSE诱导的病理通常与PrP-res沉积有关，但其神经退行性变的机制尚不清楚。这种被称为PrP的感染性病原体的性质尚不清楚，但人们认为它主要由错误折叠的PrP组成，可能与另一种宿主辅助分子(S)形成了复合体。PrPC是一种糖基磷脂酰肌醇(GPI)锚定的糖蛋白，体内产生的PrPSc大多含有这个GPI锚定。正常PrP亚型和疾病相关PrP亚型的膜结合可能影响PrPC疾病的许多特征和PrPC功能。我们的工作集中在阐明Pron的摄取、复制和传播的机制，以及确定哺乳动物Pron的生化组成。 2014年，我们继续对来自纯化的重组PrP的新型TSE制剂合成菌株进行表征，并通过在新型神经元培养系统中的成像研究，进一步研究PrPSc的摄取、繁殖和细胞间扩散的机制。与前一条研究路线相关的实验表明，我们已经分离出一种完全依赖于GPI-无锚PrPC进行繁殖的独特的合成TSE Prion。我们还探索了非神经性脑细胞在TSE感染中的作用，并发现有证据表明，与神经元相比，成纤维细胞和星形胶质细胞在感染早期可能发挥重要作用，因为PrPSc的摄取增强。在与Motohiro Horiuchi的实验室合作中，我们还证明了输入PrPSc从晚期的内切/溶酶体途径运输到内吞循环途径对于在细胞中建立普恩病毒感染是重要的。

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 2014, 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 neuronal culture systems. Experiments associated with the former line of investigation indicate we have isolated a unique synthetic TSE prion completely dependent on GPI-anchorless PrPC for propagation. We have also explored the role of non-neuronal brain cells in TSE infections and found evidence that fibroblasts and astrocytes may play an important role at early time points of infection due to enhanced uptake of PrPSc compared to neurons. In collaboration with Motohiro Horiuchi's lab, we have also shown that trafficking of input PrPSc from the late endosomal/lysosomal pathway to the endocytic recycling pathway is important for establishment of prion infection in cells.