Department of Pathology and Laboratory Medicine, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA.
Department of Neonatology, Children's Hospital of Soochow University, No. 92 Zhongnan Street, Suzhou 215025, China.
Cells. 2022 May 7;11(9):1573. doi: 10.3390/cells11091573.
We demonstrated previously that extracellular vesicles (EVs) released from mesenchymal stem cells (MSCs) play a critical role in angiogenesis. Here, we examine whether this pro-angiogenic efficacy is enhanced in EVs derived from MSCs overexpressing GATA-4 (MSC). Methods and Results. EVs were isolated from MSC (EV) and control MSCs transduced with an empty vector (EV). EVs from both cell types were of the same size and displayed similar molecular markers. Compared with EV, EV increased both a tube-like structure formation and spheroid-based sprouting of human umbilical vein endothelial cells (HUVECs). The EV increased the numbers of CD31-positive cells and hemoglobin content inside Matrigel plugs subcutaneously transplanted into mice for 2 weeks. Moreover, EV encapsulated higher levels of let-7 family miRs compared to EV. The transfer of exosomal let-7 miRs into HUVECs was recorded with an accompanied down-regulation of thrombospondin-1 (THBS1) expression, a major endogenous angiogenesis inhibitor. The loss-and-gain of function studies of let-7 miRs showed that let-7f knockdown significantly decreased EV-mediated vascularization inside Matrigel plugs. In contrast, let-7f overexpression promoted HUVEC migration and tube formation. Conclusion. Our results indicate that EVs derived from genetically modified MSCs with GATA-4 overexpression had increased pro-angiogenic capacity due to the delivery of let-7 miRs that targeted THBS1 in endothelial cells.
我们之前已经证明，间充质干细胞（MSCs）释放的细胞外囊泡（EVs）在血管生成中起着关键作用。在这里，我们研究了过表达 GATA-4 的 MSC 来源的 EV 是否增强了这种促血管生成作用。
方法和结果。从 MSC（EV）和转导有空载体的对照 MSC（EV）中分离 EVs。两种细胞类型的 EV 大小相同，显示出相似的分子标记。与 EV 相比，EV 增加了人脐静脉内皮细胞（HUVEC）的管状结构形成和球体基发芽。EV 增加了 CD31 阳性细胞的数量和皮下植入小鼠 2 周的 Matrigel 塞内的血红蛋白含量。此外，EV 包裹的 let-7 家族 miR 水平高于 EV。将外泌体 let-7 miR 转移到 HUVEC 中，伴随着血栓素-1（THBS1）表达的下调，THBS1 是一种主要的内源性血管生成抑制剂。let-7 miR 的缺失和功能获得研究表明，let-7f 敲低显著降低了 Matrigel 塞内 EV 介导的血管生成。相比之下，let-7f 过表达促进了 HUVEC 的迁移和管腔形成。
结论。我们的结果表明，由于向内皮细胞中靶向 THBS1 的 let-7 miR 的传递，过表达 GATA-4 的基因修饰 MSC 来源的 EV 具有增强的促血管生成能力。
