Yang Huai-Chun, Zhang Min, Wu Rui, Zheng Hai-Qing, Zhang Li-Ying, Luo Jing, Li Li-Li, Hu Xi-Quan
Department of Rehabilitation Medicine, the Third Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, Guangdong Province, China.
Department of Andrology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510000, Guangdong Province, China.
World J Stem Cells. 2020 Feb 26;12(2):152-167. doi: 10.4252/wjsc.v12.i2.152.
Human-derived mesenchymal stromal cells have been shown to improve cognitive function following experimental stroke. The activity of exosomes has been verified to be comparable to the therapeutic effects of mesenchymal stromal cells. However, the effects of exosomes derived from human umbilical cord mesenchymal stem cells (HUC-MSCs) (Exo) on post-stroke cognitive impairment (PSCI) have rarely been reported. Moreover, whether exosomes derived from C-C chemokine receptor type 2 (CCR2)-overexpressing HUC-MSCs (Exo) can enhance the therapeutic effects on PSCI and the possible underlying mechanisms have not been studied.
To investigate the effects of Exo on PSCI and whether Exo can enhance therapeutic effects on PSCI.
Transmission electron microscopy, qNano particles analyzer, and Western blotting were employed to determine the morphology and CCR2 expression of Exo or Exo. ELISA was used to study the binding capacity of exosomes to CC chemokine ligand 2 (CCL2) . After the intravenous injection of Exo or Exo into experimental rats, the effect of Exo and Exo on PSCI was assessed by Morris water maze. Remyelination and oligodendrogenesis were analyzed by Western blotting and immunofluorescence microscopy. QRT-PCR and immunofluorescence microscopy were conducted to compare the microglia/macrophage polarization. The infiltration and activation of hematogenous macrophages were analyzed by Western blotting and transwell migration analysis.
CCR2-overexpressing HUC-MSCs loaded the CCR2 receptor into their exosomes. The morphology and diameter distribution between Exo and Exo showed no significant difference. Exo bound significantly to CCL2 but Exo showed little CCL2 binding. Although both Exo and Exo showed beneficial effects on PSCI, oligodendrogenesis, remyelination, and microglia/macrophage polarization, Exo exhibited a significantly superior beneficial effect. We also found that Exo could suppress the CCL2-induced macrophage migration and activation and , compared with Exo treated group.
CCR2 over-expression enhanced the therapeutic effects of exosomes on the experimental PSCI by promoting M2 microglia/macrophage polarization, enhancing oligodendrogenesis and remyelination. These therapeutic effects are likely through suppressing the CCL2-induced hematogenous macrophage migration and activation.
研究表明，人源间充质基质细胞可改善实验性中风后的认知功能。外泌体的活性已被证实与间充质基质细胞的治疗效果相当。然而，人脐带间充质干细胞（HUC-MSCs）来源的外泌体（Exo）对中风后认知障碍（PSCI）的影响鲜有报道。此外，C-C趋化因子受体2（CCR2）过表达的HUC-MSCs来源的外泌体（Exo）是否能增强对PSCI的治疗效果及其潜在机制尚未得到研究。
研究Exo对PSCI的影响以及Exo是否能增强对PSCI的治疗效果。
采用透射电子显微镜、qNano颗粒分析仪和蛋白质免疫印迹法检测Exo或Exo的形态及CCR2表达。采用酶联免疫吸附测定法研究外泌体与CC趋化因子配体2（CCL2）的结合能力。将Exo或Exo经静脉注射到实验大鼠体内后，通过莫里斯水迷宫评估Exo和Exo对PSCI的影响。通过蛋白质免疫印迹法和免疫荧光显微镜分析髓鞘再生和少突胶质细胞生成。采用实时荧光定量聚合酶链反应和免疫荧光显微镜比较小胶质细胞/巨噬细胞极化情况。通过蛋白质免疫印迹法和transwell迁移分析检测血源性巨噬细胞的浸润和活化情况。
CCR2过表达的HUC-MSCs将CCR2受体载入其外泌体中。Exo和Exo之间的形态和直径分布无显著差异。Exo与CCL2有显著结合，但Exo与CCL2的结合较少。尽管Exo和Exo对PSCI、少突胶质细胞生成、髓鞘再生和小胶质细胞/巨噬细胞极化均有有益作用，但Exo的有益效果显著更优。我们还发现，与Exo治疗组相比，Exo可抑制CCL2诱导的巨噬细胞迁移和活化。
CCR2过表达通过促进M2小胶质细胞/巨噬细胞极化、增强少突胶质细胞生成和髓鞘再生，增强了外泌体对实验性PSCI的治疗效果。这些治疗效果可能是通过抑制CCL2诱导的血源性巨噬细胞迁移和活化实现的。
