Growing studies have focused on the role of microRNA-21 (miR-21) in glioma, thus our objective was to discuss the effect of M2 bone marrow-derived macrophage (BMDM)-derived exosomes (BMDM-Exos) shuffle miR-21 on biological functions of glioma cells by regulating paternally expressed gene 3 (PEG3). Seventy-one cases of human glioma tissues and 30 cases of non-tumor normal brain tissues were collected and stored in liquid nitrogen. PEG3 and miR-21 expression in glioma tissues was tested. The fasting venous blood of glioma patients and healthy control was collected and centrifuged, and then the supernatant was stored at − 80 °C refrigerator. The contents of interferon (IFN)-γ and transforming growth factor-β1 (TGF-β1) in serum were tested by ELISA. Glioma cells and normal glial cells were cultured to screen the target cells for further in vitro experiments. BMDM-Exos was obtained by ultra-high speed centrifugation and then was identified. BMDM-Exos was co-cultured with U87 cells to detect the biological functions. The fasting venous blood of glioma patients was extracted and treated with ethylene diamine tetraacetic acid-K2 anti-freezing, and then CD8+T cells were isolated. CD8+T cells were co-cultured with U87 cells to detect the CD8+T proliferation, cell cytotoxic activity, U87 cell activity, as well as IFN-γ and TGF-β1 levels. Moreover, BALB/c-nu/nu mice was taken, and the human-nude mouse glioma orthotopic transplantation model was established with U87 cells, and then mice were grouped to test the trends in tumor growth. The brain of mice (fixed by 10% formaldehyde) was sliced to detect the expression of Ki67 and proliferating cell nuclear antigen (PCNA). The spleen of mice was taken to prepare single-cell suspension, and the percentage of T lymphocytes in spleen to CD8+T cells was detected. PEG3 expression was decreased and miR-21 expression was increased in glioma cells and tissues. Depleting miR-21 or restoring PEG3 suppressed growth, migration and invasion as well as accelerated apoptosis of glioma cells, also raised CD8+T proliferation, cell cytotoxic activity, and IFN-γ level as well as decreased U87 cell activity and TGF-β1 level. BMDM-Exos shuttle miR-21 promoted migration, proliferation and invasion as well as suppressed apoptosis of glioma cells by reducing PEG3. Exosomes enhanced the volume of tumor, Ki67 and PCNA expression, reduced the percentage of CD8+T cells in glioma mice. BMDM-Exos shuffle miR-21 to facilitate invasion, proliferation and migration as well as inhibit apoptosis of glioma cells via inhibiting PEG3, furthermore, promoting immune escape of glioma cells.

中文翻译：

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M2 骨髓来源的巨噬细胞来源的外泌体改组 microRNA-21，通过调节 PEG3 加速胶质瘤的免疫逃逸

越来越多的研究集中在 microRNA-21 (miR-21) 在胶质瘤中的作用，因此我们的目标是讨论 M2 骨髓衍生巨噬细胞 (BMDM) 衍生的外泌体 (BMDM-Exos) 改组 miR-21 对通过调节父系表达的基因 3 (PEG3) 来调节胶质瘤细胞的生物学功能。收集71例人脑胶质瘤组织和30例非肿瘤正常脑组织并储存在液氮中。检测了胶质瘤组织中 PEG3 和 miR-21 的表达。采集胶质瘤患者和健康对照的空腹静脉血并离心，上清液于-80℃冰箱保存。ELISA法检测血清中干扰素（IFN）-γ和转化生长因子-β1（TGF-β1）的含量。培养胶质瘤细胞和正常胶质细胞以筛选靶细胞以进行进一步的体外实验。BMDM-Exos通过超高速离心获得，然后进行鉴定。BMDM-Exos与U87细胞共培养以检测生物学功能。提取胶质瘤患者空腹静脉血，用乙二胺四乙酸-K2抗冻液处理，分离CD8+T细胞。CD8+T细胞与U87细胞共培养，检测CD8+T增殖、细胞毒活性、U87细胞活性以及IFN-γ和TGF-β1水平。此外，取BALB/c-nu/nu小鼠，用U87细胞建立人-裸鼠胶质瘤原位移植模型，然后对小鼠进行分组检测肿瘤生长趋势。将小鼠大脑（10%甲醛固定）切片，检测Ki67和增殖细胞核抗原（PCNA）的表达。取小鼠脾脏制备单细胞悬液，检测脾脏中T淋巴细胞占CD8+T细胞的百分比。胶质瘤细胞和组织中 PEG3 表达降低，miR-21 表达增加。消耗 miR-21 或恢复 PEG3 可抑制胶质瘤细胞的生长、迁移和侵袭，加速细胞凋亡，同时提高 CD8+T 增殖、细胞毒活性和 IFN-γ 水平，并降低 U87 细胞活性和 TGF-β1 水平. BMDM-Exos 穿梭 miR-21 通过减少 PEG3 促进胶质瘤细胞的迁移、增殖和侵袭以及抑制细胞凋亡。外泌体增强了肿瘤体积、Ki67 和 PCNA 表达，降低了胶质瘤小鼠中 CD8+T 细胞的百分比。BMDM-Exos 改组 miR-21 以促进侵袭、增殖和迁移，并通过抑制 PEG3 抑制胶质瘤细胞的凋亡，进而促进胶质瘤细胞的免疫逃逸。