Xue Yan, Wan Baolan, Wang Zhen, Wang Zhiwei, Wang Dongzhi, Yang Wanping, Wang Xueting, Zhu Li
Research Center of Molecular Medicine, Nantong Health College of Jiangsu Province, Nantong 226010, China
Institute of Special Environmental Medicine, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong 226019, China
Curr Neuropharmacol. 2025 May 9. doi: 10.2174/011570159X371235250417051313.
High-altitude cerebral edema (HACE) is a serious condition caused by pro-longed hypobaric hypoxia (HH). Autophagic degradation of Claudin-5 plays a crucial role in HH-induced blood-brain barrier (BBB) damage. Hydroxychloroquine (HCQ), a lysosomal inhibitor used in autophagy treatment, reduces inflammation and BBB damage in traumatic brain injury. However, its effectiveness in preventing HACE is still unknown.
C57BL/6J mice were treated with HCQ and exposed to HH for 24 hrs to study BBB integ-rity. We evaluated BBB disruption via brain water content, Evans blue, and FITC-dextran assays. Changes in tight junctions (TJs) of cerebrovascular endothelial cells were analyzed using electron microscopy and immunofluorescence. Western blotting quantified autophagy protein levels in brain tissue. Hypoxia-mimetic in vitro models were used to explore HCQ's effects on TJs and BBB per-meability, confirmed by various assays, including immunofluorescence, electron microscopy, and Western blotting.
HCQ significantly mitigated rapamycin-induced autophagy and Claudin-5 degradation. Pro-longed hypoxia exposure promoted lysosomal degradation of Claudin-5, increasing endothelial cell permeability. HCQ inhibited autophagy in bEnd.3 cells via the PI3K-Akt-mTOR and Erk pathway, reducing hypoxia-induced Claudin-5 down-regulation. In mice, HH exposure increased brain au-tophagy, damaging the vascular endothelial TJs and subsequently increasing endothelial permeabil-ity. Pretreatment with HCQ significantly reduced the level of autophagy in the brains of HH-exposed mice, thereby mitigating the HH-induced damage to vascular TJs, alleviating the downregulation of Claudin-5, and enhancing endothelial integrity.
HCQ effectively prevented HACE by inhibiting HH-induced Claudin-5 membrane ex-pression downregulation, thus mitigating BBB damage and brain water content increase in HH-exposed mice.
高原脑水肿（HACE）是一种由长期低压缺氧（HH）引起的严重病症。Claudin-5的自噬降解在HH诱导的血脑屏障（BBB）损伤中起关键作用。羟氯喹（HCQ）是一种用于自噬治疗的溶酶体抑制剂，可减轻创伤性脑损伤中的炎症和BBB损伤。然而，其预防HACE的有效性仍不清楚。
用HCQ处理C57BL/6J小鼠，并使其暴露于HH环境24小时，以研究BBB完整性。我们通过脑含水量、伊文思蓝和异硫氰酸荧光素葡聚糖测定来评估BBB破坏情况。使用电子显微镜和免疫荧光分析脑血管内皮细胞紧密连接（TJ）的变化。蛋白质印迹法定量脑组织中的自噬蛋白水平。使用缺氧模拟体外模型探索HCQ对TJ和BBB通透性的影响，通过包括免疫荧光、电子显微镜和蛋白质印迹法在内的各种测定进行确认。
HCQ显著减轻雷帕霉素诱导的自噬和Claudin-5降解。长时间缺氧暴露促进Claudin-5的溶酶体降解，增加内皮细胞通透性。HCQ通过PI3K-Akt-mTOR和Erk途径抑制bEnd.3细胞中的自噬，减少缺氧诱导的Claudin-5下调。在小鼠中，HH暴露增加脑自噬，破坏血管内皮TJ，随后增加内皮通透性。用HCQ预处理显著降低HH暴露小鼠脑内的自噬水平，从而减轻HH诱导的血管TJ损伤，减轻Claudin-5的下调，并增强内皮完整性。
HCQ通过抑制HH诱导的Claudin-5膜表达下调有效预防HACE，从而减轻HH暴露小鼠的BBB损伤和脑含水量增加。
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