Tianjin First Central Hospital Clinic Institute, Tianjin Medical University, 300070, Tianjin, P.R. China.
Department of Organ Transplantation, Tianjin First Central Hospital, 300192, Tianjin, P.R. China.
Cell Death Dis. 2020 Jun 25;11(6):480. doi: 10.1038/s41419-020-2685-8.
Heme Oxygen-1 (HO-1)-modified bone marrow mesenchymal stem cells (BMMSCs) are effective to protect and repair transplanted small bowel and intestinal epithelial cells (IECs); however, the mechanism and the role of HO-1/BMMSCs-derived exosomes is unclear. In the present study, we aimed to verify that exosomes from a HO-1/BMMSCs and IEC-6 cells (IEC-6s) co-culture system could reduce the apoptosis of IEC-6s and decrease the expression of the tight junction protein, zona occludens 1, in the inflammatory environment. Using mass spectrometry, we revealed that high mobility group box 3 (HMGB3) and phosphorylated c-Jun NH2-terminal kinase (JNK), under the influence of differentially abundant proteins identified through proteomic analysis, play critical roles in the mechanism. Further studies indicated that microRNA miR-200b, which was upregulated in exosomes derived from the co-culture of HO-1/BMMSCs and IEC-6s, exerted its role by targeting the 3' untranslated region of Hmgb3 in this biological process. Functional experiments confirmed that miR-200b overexpression could reduce the inflammatory injury of IEC-6s, while intracellular miR-200b knockdown could significantly block the protective effect of HO-1/BMMSCs exosomes on the inflammatory injury of IEC-6s. In addition, the level of miR-200b in cells and exosomes derived from HO-1/BMMSCs stimulated by tumor necrosis factor alpha was significantly upregulated. In a rat small bowel transplantation model of allograft rejection treated with HO-1/BMMSCs, we confirmed that the level of miR-200b in the transplanted small bowel tissue was increased significantly, while the level of HMGB3/JNK was downregulated significantly. In conclusion, we identified that exosomes derived from HO-1/BMMSCs play an important role in alleviating the inflammatory injury of IECs. The mechanism is related to miR-200b targeting the abnormally increased expression of the Hmgb3 gene in IECs induced by inflammatory injury. The reduced level of HMGB3 then decreases the inflammatory injury.
血红素加氧酶-1（HO-1）修饰的骨髓间充质干细胞（BMMSCs）可有效保护和修复移植的小肠和肠上皮细胞（IECs）；然而，HO-1/BMMSCs 衍生的外泌体的机制和作用尚不清楚。在本研究中，我们旨在验证来自 HO-1/BMMSCs 和 IEC-6 细胞（IEC-6s）共培养系统的外泌体可减少 IEC-6s 的凋亡，并降低炎症环境中紧密连接蛋白，封闭蛋白 1（zona occludens 1）的表达。通过质谱分析，我们发现高迁移率族蛋白 B3（HMGB3）和磷酸化 c-Jun NH2-末端激酶（JNK）在通过蛋白质组分析鉴定的差异丰度蛋白的影响下，在该机制中发挥关键作用。进一步的研究表明，miR-200b 在 HO-1/BMMSCs 和 IEC-6s 共培养衍生的外泌体中上调，通过靶向该生物过程中 Hmgb3 的 3'非翻译区发挥作用。功能实验证实，miR-200b 过表达可减少 IEC-6s 的炎症损伤，而细胞内 miR-200b 敲低可显著阻断 HO-1/BMMSCs 外泌体对 IEC-6s 炎症损伤的保护作用。此外，肿瘤坏死因子 α 刺激的 HO-1/BMMSCs 细胞和外泌体中 miR-200b 的水平显著上调。在接受 HO-1/BMMSCs 治疗的同种异体小肠移植排斥大鼠模型中，我们证实移植小肠组织中 miR-200b 的水平显著升高，而 HMGB3/JNK 的水平显著降低。总之，我们发现 HO-1/BMMSCs 衍生的外泌体在减轻 IECs 的炎症损伤中发挥重要作用。其机制与 miR-200b 靶向炎症损伤诱导的 IEC 中异常增加的 Hmgb3 基因表达有关。HMGB3 水平的降低继而减轻炎症损伤。
