Impairments of the blood-brain barrier (BBB) and vascular dysfunction contribute to Alzheimer's disease (AD) from the earliest stages. However, the influence of AD-affected astrocytes on the BBB remain largely unexplored. In the present study, we created an in vitro BBB using human-immortalized endothelial cells in combination with immortalized astroglial cell lines from the hippocampus of 3xTG-AD and wild-type mice (3Tg-iAstro and WT-iAstro, respectively). We found that co-culturing endothelial monolayers with WT-iAstro upregulates expression of endothelial tight junction proteins (claudin-5, occludin, ZO-1) and increases the trans-endothelial electrical resistance (TEER). In contrast, co-culturing with 3Tg-iAstro does not affect expression of tight junction proteins and does not change the TEER of endothelial monolayers. The same in vitro model has been used to evaluate the effects of extracellular vesicles (EVs) derived from the WT-iAstro and 3Tg-iAstro. The EVs derived from WT-iAstro increased TEER and upregulated expression of tight junction proteins, whereas EVs from 3Tg-iAstro were ineffective. In conclusion, we show for the first time that immortalized hippocampal astrocytes from 3xTG-AD mice exhibit impaired capacity to support BBB integrity in vitro through paracrine mechanisms and may represent an important factor underlying vascular abnormalities during development of AD.

中文翻译：

---

来自 3xTG-AD 小鼠的永生化海马星形胶质细胞无法支持体外 BBB 完整性：细胞外囊泡在神经胶质-内皮细胞通讯中的作用。

血脑屏障 (BBB) 的损伤和血管功能障碍从最早阶段就导致阿尔茨海默病 (AD)。然而，受 AD 影响的星形胶质细胞对 BBB 的影响在很大程度上仍未得到探索。在本研究中，我们使用人永生化内皮细胞与来自 3xTG-AD 和野生型小鼠（分别为 3Tg-iAstro 和 WT-iAstro）海马体的永生化星形胶质细胞系结合创建了体外 BBB。我们发现，与 WT-iAstro 共培养内皮单层可上调内皮紧密连接蛋白（claudin-5、occludin、ZO-1）的表达并增加跨内皮电阻 (TEER)。相比之下，与 3Tg-iAstro 共培养不会影响紧密连接蛋白的表达，也不会改变内皮单层的 TEER。相同的体外模型已用于评估源自 WT-iAstro 和 3Tg-iAstro 的细胞外囊泡 (EV) 的影响。来自 WT-iAstro 的 EV 增加了 TEER 并上调了紧密连接蛋白的表达，而来自 3Tg-iAstro 的 EV 无效。总之，我们首次表明来自 3xTG-AD 小鼠的永生化海马星形胶质细胞表现出通过旁分泌机制在体外支持 BBB 完整性的能力受损，并且可能代表了 AD 发展过程中血管异常的重要因素。