Qiu Lina, Cai Ying, Geng Yanqin, Yao Xiuhua, Wang Lanxing, Cao Hongmei, Zhang Xuebin, Wu Qiaoli, Kong Deling, Ding Dan, Shi Yang, Wang Yuebing, Wu Jialing
Department of Neurology, Tianjin Huanhu Hospital, Tianjin 300350, China; Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurosurgical Institute, Tianjin Huanhu Hospital, Tianjin 300350, China.
Tianjin Key Laboratory of Cerebral Vascular and Neurodegenerative Diseases, Tianjin Neurosurgical Institute, Tianjin Huanhu Hospital, Tianjin 300350, China.
Acta Biomater. 2022 Dec;154:424-442. doi: 10.1016/j.actbio.2022.10.022. Epub 2022 Oct 29.
Intracerebral hemorrhage following blood-brain barrier (BBB) disruption resulting from thrombolysis of ischemic stroke with tissue plasminogen activator (tPA) remains a critical clinical problem. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are promising nanotherapeutic agents that have the potential to repair the BBB after ischemic stroke; however, whether they can attenuate BBB disruption and hemorrhagic transformation after tPA thrombolysis is largely unknown. Here, we observed that MSC-EVs efficiently passed through the BBB and selectively accumulated in injured brain regions in ischemic stroke model mice in real time using aggregation-induced emission luminogens (AIEgens), which exhibit better tracking ability than the commercially available tracer DiR. Moreover, tPA administration promoted the homing of MSC-EVs to the ischemic brain and increased the uptake of MSC-EVs by astrocytes. Furthermore, the accumulated MSC-EVs attenuated the tPA-induced disruption of BBB integrity and alleviated hemorrhage by inhibiting astrocyte activation and inflammation. Mechanistically, miR-125b-5p delivered by MSC-EVs played an indispensable role in maintaining BBB integrity by targeting Toll-like receptor 4 (TLR4) and inhibiting nuclear transcription factor-kappaB (NF-κB) signaling in astrocytes. This study provides a noninvasive method for real-time tracking of MSC-EVs in the ischemic brain after tPA treatment and highlights the potential of MSC-EVs as thrombolytic adjuvants for ischemic stroke. STATEMENT OF SIGNIFICANCE: Although tPA thrombolysis is the most effective pharmaceutical strategy for acute ischemic stroke, its clinical application and therapeutic efficacy are challenged by tPA-induced BBB disruption and hemorrhagic transformation. Our study demonstrated that MSC-EVs can act as an attractive thrombolytic adjuvant to repair the BBB and improve thrombolysis in a mouse ischemic stroke model. Notably, by labeling MSC-EVs with AIEgens, we achieved accurate real-time imaging of MSC-EVs in the ischemic brain and therapeutic visualization. MSC-EVs inhibit astrocyte activation and associated inflammation through miR-125b-5p/TLR4/NF-κB pathway. Consequently, we revealed that MSC-EVs combined with tPA thrombolysis may be a promising approach for the treatment of ischemic stroke in clinical setting.
组织型纤溶酶原激活剂（tPA）溶栓治疗缺血性中风导致血脑屏障（BBB）破坏后发生的脑出血仍然是一个关键的临床问题。间充质干细胞衍生的细胞外囊泡（MSC-EVs）是很有前景的纳米治疗剂，具有修复缺血性中风后血脑屏障的潜力；然而，它们是否能减轻tPA溶栓后的血脑屏障破坏和出血性转化在很大程度上尚不清楚。在这里，我们观察到，使用聚集诱导发光剂（AIEgens），MSC-EVs能有效穿过血脑屏障，并实时选择性地聚集在缺血性中风模型小鼠的损伤脑区，其追踪能力比市售示踪剂DiR更好。此外，给予tPA可促进MSC-EVs归巢至缺血脑，并增加星形胶质细胞对MSC-EVs的摄取。此外，积聚的MSC-EVs通过抑制星形胶质细胞激活和炎症，减轻了tPA诱导的血脑屏障完整性破坏并缓解了出血。机制上，MSC-EVs递送的miR-125b-5p通过靶向Toll样受体4（TLR4）并抑制星形胶质细胞中的核转录因子-κB（NF-κB）信号传导，在维持血脑屏障完整性中发挥不可或缺的作用。本研究提供了一种在tPA治疗后对缺血脑中的MSC-EVs进行实时追踪的非侵入性方法，并突出了MSC-EVs作为缺血性中风溶栓佐剂的潜力。重要性声明：尽管tPA溶栓是急性缺血性中风最有效的药物治疗策略，但其临床应用和治疗效果受到tPA诱导的血脑屏障破坏和出血性转化的挑战。我们的研究表明，在小鼠缺血性中风模型中，MSC-EVs可作为一种有吸引力的溶栓佐剂来修复血脑屏障并改善溶栓效果。值得注意的是，通过用AIEgens标记MSC-EVs，我们实现了对缺血脑中MSC-EVs的精确实时成像和治疗可视化。MSC-EVs通过miR-125b-5p/TLR4/NF-κB途径抑制星形胶质细胞激活及相关炎症。因此，我们揭示了MSC-EVs联合tPA溶栓可能是临床治疗缺血性中风的一种有前景的方法。
