Department of Neurosurgery, Tianjin Medical University General Hospital, Tianjin 300052, China; Laboratory of Neuro-Oncology, Tianjin Neurological Institute, Department of Neurosurgery, Tianjin Medical University General Hospital and Key Laboratory of Neurotrauma, Variation, and Regeneration, Ministry of Education and Tianjin Municipal Government, Tianjin 300052, China.
Tianjin Key Laboratory of Composite and Functional Materials, School of Material Science and Engineering, Tianjin University, Tianjin 300072, China.
J Control Release. 2022 May;345:537-548. doi: 10.1016/j.jconrel.2022.03.038. Epub 2022 Mar 25.
Exosomes are small extracellular vehicles which could transport genetic materials and proteins between cells. Although there are reports about exosomes crossing the blood-brain barrier (BBB), the underlying mechanisms still need further study. We found that exosomes from primary brain tumors could upregulate the expression of Lipocalin-2 (LCN2) in bEnd.3 brain microvascular endothelial cells (BMVECs). Furthermore, exosomes increased the membrane fluidity of bEnd.3 cells in an LCN2 dependent manner. Both intraperitoneal injection and caudal vein injection of LCN2 increased the number of nanocapsules crossing the BBB. Evans Blue staining revealed that LCN2 does not interrupt the integrity of the BBB, as observed in the traumatic brain injury model. Tandem mass tags quantitative proteomics and bioinformatics analysis revealed that LCN2 is upregulated by exosomes via the JAK-STAT3 pathway, but not delivered from exosomes. Knocking down LCN2 in bEnd.3 cells significantly abrogated the effect of exosomes on BMVEC membrane fluidity. Previously, we have reported that 2-methacryloyloxyethyl phosphorylcholine (MPC) and a peptide crosslinker could encapsulate mAbs to achieve nanocapsules. The nanocapsules containing choline analogs could effectively penetrate the BBB to deliver therapeutic monoclonal antibodies (tAbs) to the glioma. However, the delivered tAbs could be significantly reduced by blocking the release of exosomes from the gliomas. Application of tAb nanocapsules prior to treatment with MK2206, an AKT pathway inhibitor that has been shown to inhibit the production of exosomes, resulted in a better combination. Insights from this study provide a mechanistic framework with regard to how glioblastomas hijack BMVECs using exosomes. In addition, we provide a strategy for maximizing the effect of the choline-containing nanocapsules and MK2206 combination. These results also demonstrate the therapeutic role of tAbs in glioblastoma and brain tumor metastasis, by shedding new light on strategies that can be used for BBB-penetrating therapies.
外泌体是一种能够在细胞间运输遗传物质和蛋白质的小型细胞外载体。虽然有报道称外泌体可以穿越血脑屏障（BBB），但其潜在机制仍需要进一步研究。我们发现，原发性脑肿瘤的外泌体可以上调脑微血管内皮细胞（BMVEC）中脂联素 2（LCN2）的表达。此外，外泌体以 LCN2 依赖的方式增加了 bEnd.3 细胞的膜流动性。腹腔注射和尾静脉注射 LCN2 均可增加穿过 BBB 的纳米胶囊数量。伊文思蓝染色显示，LCN2 不会像在创伤性脑损伤模型中那样破坏 BBB 的完整性。串联质量标签定量蛋白质组学和生物信息学分析表明，LCN2 是通过外泌体的 JAK-STAT3 途径上调的，而不是从外泌体中传递的。在 bEnd.3 细胞中敲低 LCN2 可显著阻断外泌体对 BMVEC 膜流动性的影响。此前，我们已经报道过 2-甲基丙烯酰氧基乙基磷酸胆碱（MPC）和肽交联剂可以包封单抗以实现纳米胶囊。含有胆碱类似物的纳米胶囊可以有效地穿透 BBB 将治疗性单克隆抗体（tAb）递送至神经胶质瘤。然而，通过阻断神经胶质瘤中外泌体的释放，可显著减少递送的 tAb。在应用 AKT 通路抑制剂 MK2206 治疗之前应用 tAb 纳米胶囊，该抑制剂已被证明可抑制外泌体的产生，结果更好。这项研究的结果为神经胶质瘤如何利用外泌体劫持 BMVECs 提供了一个机制框架。此外，我们还提供了一种最大限度发挥含胆碱纳米胶囊和 MK2206 联合作用的策略。这些结果还通过揭示可用于穿透 BBB 治疗的策略，为神经胶质瘤和脑肿瘤转移的治疗作用提供了新的视角。
