Novel experimental models to study the effect of extracellular vesicles on neurons

细胞外小泡(EVS)在生物学研究的几乎每一个领域都占据着中心舞台，包括 神经生物学。EV是一种分泌囊泡，可以将脂质、rna/dna和蛋白质从供体输送到受体。 细胞，包括致病多肽和蛋白，如Aβ、tau和突触核蛋白。因此，传播的 EVS在阿尔茨海默病(AD)和帕金森病(PD)中的致病因素是近年来许多研究的焦点 学习。然而，内源性EVS的生理意义和作用机制如下 很大程度上是未知的。一个关键的知识差距和进步的障碍是我们缺乏对 由于体内模型的缺乏，EVS的生理和病理功能。 我们发现，由星形胶质细胞分泌并富含神经鞘脂神经酰胺(“星形胶质”)的EV是 被神经元摄取并运输到线粒体。我们发现中性的遗传缺陷 鞘磷脂酶2(NSMase2)是一种通过神经鞘蛋白水解产生神经酰胺的酶，它能减少 星体和上调与神经元发育和信号转导相关的转录簇， 这表明星形体能调节神经功能。 为了测试星形体对神经元的调节，我们建议建立新的技术和模型 电动汽车功能分析。我们建立了星形胶质细胞特异性nSMase2缺乏的小鼠模型(丢失 功能)模型和荧光标记星形体分泌(报告模型)。我们将主要使用 这些模型有助于了解内源性星形胶质细胞对正常神经功能的意义。我们会 结合试点研究以了解星体在(变化的)生理条件下的功能(例如， 老化)。 我们的总体目标是建立新的技术来确定星体的体内功能。一次 这些技术已经建立，可以用于从其他类型的细胞(神经元， 小胶质细胞或任何其他组织和细胞类型)

Extracellular vesicles (EVs) have taken center stage in almost every area of biological research, including neurobiology. EVs are secreted vesicles that transport lipids, RNA/DNA, and proteins from a donor to a recipient cell, including pathogenic peptides and proteins such as Aβ, tau, and synuclein. Therefore, spreading of pathogenic factors by EVs in Alzheimer’s disease (AD) and Parkinson’s Disease (PD) is the focus of many recent studies. However, the physiological significance of endogenously generated EVs and mechanism of function are largely unknown. A critical knowledge gap and barrier to progress is our lack of understanding of the physiological and pathological function of EVs due to the scarcity of in vivo models. We showed that EVs secreted by astrocytes and enriched with the sphingolipid ceramide (“astrosomes”) are taken up by neurons and transported to mitochondria. We discovered that genetic deficiency of neutral sphingomyelinase 2 (nSMase2), an enzyme generating ceramide by hydrolysis of sphingomyelin, reduces astrosomes and upregulates transcript clusters associated with neuronal development and signal transduction, suggesting that astrosomes regulate neuronal function. To test the regulation of neurons by astrosomes, we propose to establish novel techniques and models for EV functional analysis. We developed mouse models with-astrocyte specific nSMase2 deficiency (loss-of- function) models and secretion of fluorescently labeled astrosomes (reporter models). We will primarily use these models to understand the significance of endogenous astrosomes for normal neuronal function. We will incorporate pilot studies to understand the function of astrosomes in (changing) physiological conditions (e.g., aging). Our overall goal is to establish novel techniques to determine the in vivo function of astrosomes. Once established, these techniques can be adapted to determine the function of EVs from other cell types (neurons, microglia, or any other tissue and cell type) as well