Shao Lianbo, Chen Yihuan, Li Jingjing, Chao Jingfan, Yang Ziying, Ding Yinglong, Shen Han, Chen Yueqiu, Shen Zhenya
Department of Cardiovascular Surgery of the First Affiliated Hospital & Institute for Cardiovascular Science, Soochow University, Suzhou, China.
Stem Cells Int. 2023 Jan 13;2023:1662182. doi: 10.1155/2023/1662182. eCollection 2023.
Myocardial infarction is a leading cause of mortality worldwide. Angiogenesis in the infarct border zone is vital for heart function restoration after myocardial infarction. Hypoxia-induced MSC modification is a safe and effective approach for angiogenesis in clinical therapy; however, the mechanism still requires further investigation. In our study, we preconditioned human umbilical cord mesenchymal stem cells (huMSCs) with hypoxia and isolated the small extracellular vesicles (sEVs) to promote cardiac repair. We also investigated the potential mechanisms.
huMSCs were preconditioned with hypoxia (1% O and 5% CO at 37°C for 48 hours), and their sEVs were isolated using the Total Exosome Isolation reagent kit. To explore the role of miR-214 in MSC-derived sEVs, sEVs with low miR-214 expression were prepared by transfecting miR-214 inhibitor into huMSCs before hypoxia pretreatment. Scratch assays and tube formation assays were performed in sEVs cocultured with HUVECs to assess the proangiogenic capability of MSC-sEVs and MSC-sEVs. Rat myocardial infarction models were used to investigate the ability of miR-214-differentially expressed sEVs in cardiac repair. Echocardiography, Masson's staining, and immunohistochemical staining for CD31 were performed to assess cardiac function, the ratio of myocardial fibrosis, and the capillary density after sEV implantation. The potential mechanism by which MSC-sEVs enhance angiogenesis was explored by RT-qPCR and western blotting.
Tube formation and scratch assays demonstrated that the proangiogenic capability of huMSC-derived sEVs was enhanced by hypoxia pretreatment. Echocardiography and Masson's staining showed greater improvements in heart function and less ventricular remodeling after MSC-sEV transplantation. The angiogenic capability was reduced following miR-214 knockdown in MSC-sEVs. Furthermore, Sufu, a target of miR-214, was decreased, and hedgehog signaling was activated in HUVECs.
We found that hypoxia induced miR-214 expression both in huMSCs and their sEVs. Transplantation of MSC-sEVs into a myocardial infarction model improved cardiac repair by increasing angiogenesis. Mechanistically, MSC-sEVs promote HUVEC tube formation and migration by transferring miR-214 into recipient cells, inhibiting Sufu expression, and activating the hedgehog pathway. Hypoxia-induced vesicle modification is a feasible way to restore heart function after myocardial infarction.
心肌梗死是全球范围内主要的死亡原因。梗死边缘区的血管生成对于心肌梗死后心脏功能的恢复至关重要。缺氧诱导的间充质干细胞修饰是临床治疗中一种安全有效的血管生成方法；然而，其机制仍需进一步研究。在我们的研究中，我们用缺氧预处理人脐带间充质干细胞（huMSCs）并分离小细胞外囊泡（sEVs）以促进心脏修复。我们还研究了潜在机制。
用缺氧（37°C下1%氧气和5%二氧化碳，处理48小时）预处理huMSCs，并用总外泌体分离试剂盒分离其sEVs。为了探索miR-214在间充质干细胞来源的sEVs中的作用，在缺氧预处理前将miR-214抑制剂转染到huMSCs中，制备miR-214表达低的sEVs。在与HUVECs共培养的sEVs中进行划痕试验和管形成试验，以评估间充质干细胞-sEVs和间充质干细胞-sEVs的促血管生成能力。使用大鼠心肌梗死模型研究miR-214差异表达的sEVs在心脏修复中的能力。进行超声心动图、Masson染色和CD31免疫组织化学染色，以评估sEV植入后的心脏功能、心肌纤维化比例和毛细血管密度。通过RT-qPCR和蛋白质印迹法探索间充质干细胞-sEVs增强血管生成的潜在机制。
管形成试验和划痕试验表明，缺氧预处理增强了huMSC来源的sEVs的促血管生成能力。超声心动图和Masson染色显示，间充质干细胞-sEV移植后心脏功能有更大改善，心室重构更少。间充质干细胞-sEVs中miR-214敲低后血管生成能力降低。此外，miR-214的靶标Sufu减少，并且HUVECs中的刺猬信号通路被激活。
我们发现缺氧诱导huMSCs及其sEVs中miR-214表达。将间充质干细胞-sEVs移植到心肌梗死模型中可通过增加血管生成改善心脏修复。机制上，间充质干细胞-sEVs通过将miR-214转移到受体细胞中、抑制Sufu表达并激活刺猬通路来促进HUVEC管形成和迁移。缺氧诱导的囊泡修饰是心肌梗死后恢复心脏功能的一种可行方法。
