Department of Neurosurgery, The First Affiliated Hospital, Hengyang Medical School, University of South China.
Department of Neurology, The First Affiliated Hospital, Hengyang Medical School, University of South China.
Arch Biochem Biophys. 2022 May 30;721:109193. doi: 10.1016/j.abb.2022.109193. Epub 2022 Mar 20.
Stroke is a life-threatening neurological disorder with limited therapeutic efficacy. Previous studies have demonstrated that macrophages play an important role in brain injury after a stroke. However, its underlying mechanism remains unclear and the role of exosomes derived from M2-polarized macrophages (M2-Exo) in ischemic stroke has not yet been reported. In this study, we established an in vitro oxygen/glucose deprivation and re-oxygen/glucose (OGD/R) model to investigate the potential role of M2-Exo in protecting HT22 neurons against ischemia-reperfusion injury. Interleukin-4 was used to induce the M2 phenotype in macrophages, following which the exosomes were isolated from the supernatant of M2-polarized macrophages and identified by western blotting, transmission electron microscopy, and nanoparticle tracking analysis. After co-incubation with M2-Exo, OGD/R-induced neuronal injury in HT22 cells was improved, accompanied by increased cell viability and decreased lactate dehydrogenase release. In addition, the increase in percentage of terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end labeling-positive cells in OGD/R-treated HT22 cells was attenuated after incubation with M2-Exo. M2-Exo treatment also suppressed reactive oxygen species and malondialdehyde production and improved the reduction of superoxide dismutase activity. Moreover, M2-Exo treatment was found to activate the nuclear factor erythroid related factor 2 (Nrf2)/heme-oxygenase-1 (HO-1) signaling pathway in OGD/R-treated HT22 neurons. Importantly, inhibition of Nrf2 by ML385 partially reversed the protective effects of M2-Exo against OGD/R-induced oxidative damage. Taken together, these data demonstrated that M2-Exo exerted protective effects against OGD/R-induced oxidative damage in HT22 neurons, which was mediated by the activation of Nrf2/HO-1 signaling. Hence, our findings provide a promising therapeutic approach for ischemic stroke.
中风是一种危及生命的神经系统疾病，其治疗效果有限。先前的研究表明，巨噬细胞在中风后的脑损伤中发挥重要作用。然而，其潜在机制尚不清楚，并且源自 M2 极化巨噬细胞（M2-Exo）的外泌体在缺血性中风中的作用尚未报道。在这项研究中，我们建立了体外氧/葡萄糖剥夺和再氧/葡萄糖（OGD/R）模型，以研究 M2-Exo 保护 HT22 神经元免受缺血再灌注损伤的潜在作用。白细胞介素 4 用于诱导巨噬细胞的 M2 表型，然后从 M2 极化巨噬细胞的上清液中分离出外泌体，并通过 Western blot、透射电子显微镜和纳米颗粒跟踪分析进行鉴定。与 M2-Exo 共孵育后，OGD/R 诱导的 HT22 细胞神经元损伤得到改善，同时细胞活力增加，乳酸脱氢酶释放减少。此外，与 OGD/R 处理的 HT22 细胞相比，经 M2-Exo 孵育后，末端脱氧核苷酸转移酶介导的 dUTP-地高辛尼克末端标记阳性细胞的百分比增加得到减弱。M2-Exo 处理还抑制活性氧和丙二醛的产生，并改善超氧化物歧化酶活性的降低。此外，发现 M2-Exo 处理可激活核因子红细胞相关因子 2（Nrf2）/血红素加氧酶 1（HO-1）信号通路在 OGD/R 处理的 HT22 神经元中。重要的是，用 ML385 抑制 Nrf2 部分逆转了 M2-Exo 对 OGD/R 诱导的氧化损伤的保护作用。综上所述，这些数据表明，M2-Exo 对 HT22 神经元 OGD/R 诱导的氧化损伤具有保护作用，其机制是通过激活 Nrf2/HO-1 信号通路。因此，我们的研究结果为缺血性中风提供了一种有前途的治疗方法。
