Mechanisms of Prion Spread and Neuronal Toxicity

突触功能障碍和神经性营养不良是Prion-And的显著病理特征 阿尔茨海默氏症影响的大脑。泛素化的蛋白质包涵体也经常被观察到， 提供了蛋白质抑制通路受损的有力证据。细胞膜泛素化 蛋白质和ESCRT途径的清除(内体分选复合体需要 运输)是维持突触内稳态的关键。在这里，我们将深入调查 ESCRT途径在Pron病突触动态平衡紊乱中的作用。在普恩病毒感染的小鼠中，我们发现ESCRT-0(一种HRS和STAM1蛋白复合体)显著减少 以及突触体内泛素化蛋白的丰富。令人惊讶的是，耗尽神经元的HRS 感染普恩病毒的小鼠存活时间缩短，突触退化加速， 从生化和结构上来说。此外，在一项对感染了普里恩病毒的 海马区，我们发现突触活性反应基因Arc/Arg3.1上调，并且 磷酸化的CaMKII和磷酸化AMPA受体的慢性升高，提示 突触功能在疾病早期就开始增强和改变。我们的长期目标是 破译Prion和淀粉样蛋白-β寡聚体如何扰乱与细胞Prion相关的信号通路 蛋白质，导致蛋白抑制功能障碍和突触变性。利用电生理学， 未感染和感染病毒的培养物的相关光电子显微镜和蛋白质组学研究 对于神经元，我们将首先确定HRs的表达如何影响突触，评估活性，突触前和突触后的蛋白质，结构和信号。然后我们将测试不同的普里子 构象影响ESCRT途径和谷氨酸能突触的神经元信号。 最后，我们将研究谷氨酸受体活性对病毒传播的贡献。 神经退行性变。我们将直接测试这些基因操纵模型中的发现 与人类普恩病毒感染的大脑进行比较。这些研究首次测试了神经元的活动 普恩病毒传播、突触退变和疾病进展的影响和结果是 预计将为推动神经元丢失的放松管制的突触信号提供关键见解， 从而揭示了新的治疗靶点。

Synaptic dysfunction and neuritic dystrophy are prominent pathologic features of the prion- and Alzheimer’s disease-affected brain. Ubiquitinated protein inclusions are also commonly observed, providing strong evidence of impaired proteostatic pathways. Ubiquitination of cell membrane proteins and clearance through the ESCRT pathway (endosomal sorting complex required for transport) is critical to maintaining synaptic homeostasis. Here we will deeply investigate the ESCRT pathway contributions to disrupted synaptic homeostasis in prion disease. In prion-infected mice, we have found markedly reduced ESCRT-0 (an Hrs and STAM1 protein complex) and an enrichment of ubiquitinated proteins in synaptosomes. Strikingly, depleting neuronal Hrs in prion-infected mice shortened survival time and accelerated the degeneration of synapses, biochemically and structurally. Additionally, in a longitudinal study of the prion-infected hippocampus, we found an upregulation in the synaptic activity response gene, Arc/Arg3.1, and a chronic elevation in phosphorylated CaMKII and phosphorylated AMPA receptors, suggestive of enhanced and altered synapse function beginning in early disease. Our long-term goal is to decipher how prion and amyloid-β oligomers disrupt signaling pathways linked to the cellular prion protein, inducing proteostatic dysfunction and synaptic degeneration. Using electrophysiology, correlative light-electron microscopy, and proteomics on uninfected and prion-infected cultured neurons, we will first determine how Hrs expression impacts synapses, assessing activity, pre-and post-synaptic proteins, structure, and signaling. We will then test how distinct prion conformers impact the ESCRT pathway and neuronal signaling at glutamatergic synapses. Finally, we will investigate the contribution of glutamate receptor activity to prion spread and neurodegeneration. We will directly test how the findings in these genetically manipulated models compare to human prion-affected brain. These studies are the first to test how neuronal activity impacts prion dissemination, synaptic degeneration, and disease progression, and outcomes are expected to provide key insights into the deregulated synaptic signaling that drives neuron loss, thus revealing new therapeutic targets.