Fundamental biology of neuronal extracellular vesicles

项目摘要 细胞外囊泡携带Aβ和tau蛋白，可将致病蛋白传播到整个大脑，促进Aβ 聚集和加速淀粉样斑块的形成，也可能作为阿尔茨海默氏症的生物标志物 疾病来自血液、脑脊液和细胞培养物的EV含有Aβ和tau， 阿尔茨海默病病理学进展中的中枢介质。相反，EV可能具有 阿尔茨海默病的益处：神经元衍生的EV促进小胶质细胞对Aβ的摄取， 培养细胞中的细胞外Aβ水平。EV分泌的上调-由中性粒细胞诱导 鞘磷脂酶敲低-有效降低神经元共培养物中的细胞外Aβ水平 和小胶质细胞。EV在阿尔茨海默病中的作用目前是该疾病的一大谜团 机制我们将研究神经元EV脱落是如何被阿尔茨海默氏症相关因素所调节的 疾病，包括年龄，氧化应激，蛋白质稳态和神经胶质功能障碍。几乎所有细胞 脑中的细胞类型释放EV，包括干细胞、神经元、星形胶质细胞、小胶质细胞和少突胶质细胞。 EV可以被细胞用作细胞间通讯的一种形式，并且因此可以介导广泛的细胞间通讯。 一系列生理和病理过程。细胞包装有益或有毒的EV货物，以促进 健康或疾病。在哺乳动物神经系统中，电动汽车具有抗氧化的神经保护作用 应激、细胞应激和缺血;并且还可以促进衰老中的髓鞘形成。在大脑中，电动汽车可能 携带易于聚集的货物，并有助于阿尔茨海默病的传播。了解 体内基于EV的信号传导的基础生物学对于阐述它们的生理和 阿尔茨海默病的病理功能。基本的分子解剖对于开发 新的治疗应用。 生物学一直被一个 然而，一个大问题是， 缺乏易驾驭的实验动物系统。我们建议采取 强大和无与伦比的细胞生物学和分子方法的优势，可以应用 线虫C. elegans作为研究体内神经元EV的基础生物学的跳板。 我们开发了第一个系统来研究生活中神经元EV的生物发生，脱落，靶向和信号传导。 动物，这种策略将克服基于细胞培养的研究的局限性。这种创新方法 将用于解决电动汽车领域的主要挑战。我们的目标是：1）确定 神经元活动、年龄和应激对神经元EV脱落和信号传导的影响; 2）解密分子 控制神经元EV脱落的机制;和3）确定神经元EV在长- 远距离细胞间通讯和神经元-胶质细胞通讯。我们的工作应该告知 与健康大脑衰老和阿尔茨海默病相关的神经元EV的基础生物学， 确定治疗目标，以对抗与异常EV信号相关的阿尔茨海默氏症等疾病。

Project Summary Extracellular vesicles carry Aβ and tau that may spread pathogenic proteins across the brain, promote Aβ aggregation and accelerate amyloid plaque formation, and may also serve as biomarkers of Alzheimer's disease. EVs from blood, cerebral spinal fluid, and cell culture contain Aβ and tau and are proposed to be central mediators in the progression of Alzheimer's disease pathology. Conversely, EVs may have benefits in Alzheimer's disease: neuron-derived EVs promote uptake of Aβ by microglia and reduce extracellular levels of Aβ in cultured cells. Up-regulation of EV secretion - induced by neutral sphingomyelinase knockdown - efficiently reduced extracellular levels of Aβ in a co-culture of neuronal and microglial cells. The role of EVs in Alzheimer's disease is currently a major mystery of the disease mechanism. We will study how neuronal EV shedding is modulated by factors relevant to Alzheimer's disease, including age, oxidative stress, and proteostasis and neuron-glia dysfunction. Virtually all cell types in the brain release EVs including stem cells, neurons, astrocytes, microglia, and oligodendrocytes. EVs may be used by cells as a form of intercellular communication and may thereby mediate a broad range of physiological and pathological processes. Cells package beneficial or toxic EV cargo to promote health or disease. In the mammalian nervous system, EVs have neuroprotective roles against oxidative stress, cellular stress, and ischemia; and may also promote myelination in aging. In the brain, EVs may carry aggregation-prone cargo and contribute to the spread of Alzheimer's diseases. Understanding the fundamental biology of an EV-based signaling in vivo is essential for elaborating their physiological and pathological functions in Alzheimer's disease. A basic molecular dissection is critical for developing novel therapeutic applications. biology has been thwarted by a A big problem, however, is that advancing mechanistic dissection of EV lack of tractable experimental animal systems. We propose to take advantage of the powerful and unparalleled cell biological and molecular approaches that can be applied in the nematode C. elegans as a springboard to study the fundamental biology of neuronal EVs in vivo. We developed the first system to study neuronal EV biogenesis, shedding, targeting and signaling in living animals, and this strategy will overcome limitations of cell-culture based studies. This innovative approach will be used to tackle major challenges in the EV field . Our goals are to: 1) Determine the impact of neuronal activity, age and stress on neuronal EV shedding and signaling; 2) Decipher molecular mechanisms that control neuronal EV shedding; and 3) Determine the functions of neuronal EVs in long- distance intercellular communication and in neuron-glia communication. Our work should inform the fundamental biology of neuronal EVs relevant to both healthy brain aging and Alzheimer's disease and identify therapeutic targets to combat diseases like Alzheimer's associated with abnormal EV signaling.