Astrocytes in the central nervous system (CNS) provide supportive neural functions and mediate inflammatory responses from microglia. Increasing evidence supports their critical roles in regulating brain homoeostasis in response to pro-inflammatory factors such as cytokines and pathogen/damage-associated molecular pattern molecules in infectious and neurodegenerative diseases. However, the underlying mechanisms of the trans-cellular communication are still unclear. Extracellular vesicles (EVs) can transfer a large diversity of molecules such as lipids, nucleic acids and proteins for cellular communications. The purpose of this study is to characterize the EVs cargo proteins derived from human primary astrocytes (ADEVs) under both physiological and pathophysiological conditions. ADEVs were isolated from human primary astrocytes after vehicle (CTL) or interleukin-1β (IL-1β) pre-treatment. Label-free quantitative proteomic profiling revealed a notable up-regulation of proteins including actin-associated molecules, integrins and major histocompatibility complex in IL-1β-ADEVs compared to CTL-ADEVs, which were involved in cellular metabolism and organization, cellular communication and inflammatory response. When fluorescently labelled ADEVs were added into primary cultured mouse cortical neurons, we found a significantly increased neuronal uptake of IL-1β-ADEVs compared to CTL-ADEVs. We further confirmed it is likely due to the enrichment of surface proteins in IL-1β-ADEVs, as IL-1β-ADEVs uptake by neurons was partially suppressed by a specific integrin inhibitor. Additionally, treatment of neurons with IL-1β-ADEVs also reduced neurite outgrowth, branching and neuronal firing. These findings provide insight for the molecular mechanism of the ADEVs' effects on neural uptake, neural differentiation and maturation, and its alteration in inflammatory conditions.

中文翻译：

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活化的人类星形胶质细胞源性小泡调节神经元的摄取，分化和射击。

中枢神经系统（CNS）中的星形胶质细胞提供支持性神经功能并介导小胶质细胞的炎症反应。越来越多的证据支持它们在调节促炎因素（如感染性疾病和神经退行性疾病中的细胞因子和与病原体/损伤相关的分子模式分子）反应中在调节脑稳态中的关键作用。但是，跨细胞通信的潜在机制仍不清楚。细胞外囊泡（EV）可以转移大量分子，例如脂质，核酸和蛋白质，以进行细胞通讯。这项研究的目的是在生理和病理生理条件下表征源自人类原代星形胶质细胞（ADEV）的EV货物蛋白。经过媒介物（CTL）或白介素-1β（IL-1β）预处理后，从人原代星形胶质细胞中分离出ADEV。与CTL-ADEV相比，IL-1β-ADEV中无标记的定量蛋白质组学分析显示蛋白质显着上调，包括肌动蛋白相关分子，整联蛋白和主要组织相容性复合物，CTL-ADEV参与细胞代谢和组织，细胞通讯和炎症回复。当将荧光标记的ADEV添加到原代培养的小鼠皮质神经元中时，我们发现与CTL-ADEV相比，IL-1β-ADEV的神经元摄取显着增加。我们进一步证实，这很可能是由于IL-1β-ADEV中表面蛋白的富集所致，因为特定整联蛋白抑制剂可部分抑制神经元对IL-1β-ADEV的摄取。此外，用IL-1β-ADEV治疗神经元也减少了神经突生长，分支和神经元放电。这些发现为深入了解ADEV对神经摄取，神经分化和成熟及其在炎症条件下的改变的分子机制提供了见识。