Zhang Xiaomei, Lu Aizhen, Li Zhi, Sun Jiali, Dai Dan, Qian Liling
Respiratory Department, Children's Hospital of Fudan University, Shanghai 201102, China.
The Children's Hospital of Zhejiang University, School of Medicine, Hangzhou 310052, China.
Ann Transl Med. 2019 Jun;7(12):254. doi: 10.21037/atm.2019.05.10.
Paracrine factors secreted by endothelial progenitor cells (EPCs) are suggested to be responsible, in part, for the improved microvascular development in bronchopulmonary dysplasia (BPD) models. This study aims to investigate the potential role of exosomes derived from EPCs (EPC-EXOs), a component of paracrine secretion, in angiogenesis by mediating the activity of PMVECs exposed to hyperoxia.
EPCs were isolated from bone marrow of rats. EPC-EXOs were isolated by ExoQuick-TC kits from the conditioned media of EPCs. The PMVECs were divided into three groups, including the normal group, the hyperoxia group (exposed to 85% O) and the EPC-EXOs treatment group (exposed to 85% O and EPC-EXOs with the concentration of 100 µg/mL). The activities of proliferation, migration and tube formation of PMVECs were detected at the endpoint. The mRNA and protein expression levels of VEGF, VEGFR2 and eNOS in different groups were detected by real-time quantitative PCR and western blot.
We found EPC-EXOs exhibited a cup or biconcave morphology, with the size ranging from 30 to 150 nm, and positive for the characteristic exosomal surface marker proteins, CD63 and TSG101. Comparing to the control group, Hyperoxic stress impaired the proliferation, migration, and tubule formation of PMVECs, and decreased the expression of endothelial nitric oxide synthase (eNOS), vascular endothelial growth factor (VEGF), and vascular endothelial growth factor receptor 2 (VEGFR-2) of PMVECs. Comparing to the hyperoxia group, EPC-EXOs treatment enhanced the bioactivity of PMVECs , and increased the expression of eNOS, VEGF and VEGFR2.
Our data demonstrate EPCs secrete exosomes that have independent angiogenic activity . This may help explain in part the protective effects of EPCs on hyperoxic injury in the developing lung vasculature and may represent a promising therapeutic strategy for BPD.
内皮祖细胞（EPCs）分泌的旁分泌因子被认为部分负责支气管肺发育不良（BPD）模型中微血管发育的改善。本研究旨在探讨EPCs来源的外泌体（EPC-EXOs），一种旁分泌分泌物的成分，通过介导暴露于高氧环境的肺微血管内皮细胞（PMVECs）的活性在血管生成中的潜在作用。
从大鼠骨髓中分离EPCs。通过ExoQuick-TC试剂盒从EPCs的条件培养基中分离EPC-EXOs。将PMVECs分为三组，包括正常组、高氧组（暴露于85%氧气）和EPC-EXOs治疗组（暴露于85%氧气并给予浓度为100μg/mL的EPC-EXOs）。在实验终点检测PMVECs的增殖、迁移和管形成活性。通过实时定量PCR和蛋白质印迹法检测不同组中血管内皮生长因子（VEGF）、血管内皮生长因子受体2（VEGFR2）和内皮型一氧化氮合酶（eNOS）的mRNA和蛋白质表达水平。
我们发现EPC-EXOs呈现杯状或双凹形态，大小范围为30至150nm，并且外泌体特征性表面标志物蛋白CD63和TSG101呈阳性。与对照组相比，高氧应激损害了PMVECs的增殖、迁移和小管形成，并降低了PMVECs中内皮型一氧化氮合酶（eNOS）、血管内皮生长因子（VEGF）和血管内皮生长因子受体2（VEGFR-2）的表达。与高氧组相比，EPC-EXOs治疗增强了PMVECs的生物活性，并增加了eNOS、VEGF和VEGFR2的表达。
我们的数据表明EPCs分泌具有独立血管生成活性的外泌体。这可能部分解释了EPCs对发育中的肺血管系统高氧损伤的保护作用，并可能代表一种有前景的BPD治疗策略。
