State Key Laboratory of Chemical Oncogenomics, and Shenzhen Key Laboratory of Health Sciences and Technology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, China.
School of Life Sciences, Tsinghua University, Beijing, 100084, China.
Stem Cell Res Ther. 2021 Jun 21;12(1):358. doi: 10.1186/s13287-021-02416-4.
We show previously that three-dimensional (3D) spheroid cultured mesenchymal stem cells (MSCs) exhibit reduced cell size thus devoid of lung entrapment following intravenous (IV) infusion. In this study, we determined the therapeutic effect of 3D-cultured MSCs on ischemic stroke and investigated the mechanisms involved.
Rats underwent middle cerebral artery occlusion (MCAO) and reperfusion. 1 × 10 of 3D- or 2D-cultured MSCs, which were pre-labeled with GFP, were injected through the tail vain three and seven days after MCAO. Two days after infusion, MSC engraftment into the ischemic brain tissues was assessed by histological analysis for GFP-expressing cells, and infarct volume was determined by MRI. Microglia in the lesion were sorted and subjected to gene expressional analysis by RNA-seq.
We found that infusion of 3D-cultured MSCs significantly reduced the infarct volume of the brain with increased engraftment of the cells into the ischemic tissue, compared to 2D-cultured MSCs. Accordingly, in the brain lesion of 3D MSC-treated animals, there were significantly reduced numbers of amoeboid microglia and decreased levels of proinflammatory cytokines, indicating attenuated activation of the microglia. RNA-seq of microglia derived from the lesions suggested that 3D-cultured MSCs decreased the response of microglia to the ischemic insult. Interestingly, we observed a decreased expression of mincle, a damage-associated molecular patterns (DAMPs) receptor, which induces the production of proinflammatory cytokines, suggestive of a potential mechanism in 3D MSC-mediated enhanced repair to ischemic stroke.
Our data indicate that 3D-cultured MSCs exhibit enhanced repair to ischemic stroke, probably through a suppression to ischemia-induced microglial activation.
我们之前表明，三维（3D）球体培养的间充质干细胞（MSCs）表现出细胞体积减小，因此静脉（IV）输注后不会被肺部截留。在这项研究中，我们确定了 3D 培养的 MSCs 对缺血性中风的治疗效果，并研究了相关机制。
大鼠进行大脑中动脉闭塞（MCAO）和再灌注。在 MCAO 后 3 天和 7 天，通过尾静脉注射 1×10 的 3D 或 2D 培养的 GFP 预标记的 MSC。输注后 2 天，通过 GFP 表达细胞的组织学分析评估 MSC 向缺血性脑组织的植入情况，并通过 MRI 确定梗死体积。对病变中的小胶质细胞进行分选，并通过 RNA-seq 进行基因表达分析。
我们发现，与 2D 培养的 MSC 相比，输注 3D 培养的 MSC 可显著减少大脑的梗死体积，并增加细胞向缺血组织的植入。因此，在 3D MSC 治疗动物的脑损伤部位，阿米巴样小胶质细胞数量明显减少，促炎细胞因子水平降低，表明小胶质细胞的激活减弱。从小胶质细胞病变中提取的 RNA-seq 表明，3D 培养的 MSC 降低了小胶质细胞对缺血损伤的反应。有趣的是，我们观察到损伤相关分子模式（DAMPs）受体 mincle 的表达降低，该受体诱导促炎细胞因子的产生，提示 3D MSC 介导的增强对缺血性中风修复的潜在机制。
我们的数据表明，3D 培养的 MSC 对缺血性中风表现出增强的修复作用，可能是通过抑制缺血诱导的小胶质细胞激活。
