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.

血红素氧1（HO-1）修饰的骨髓间充质干细胞（BMMSC）可有效保护和修复移植的小肠和肠上皮细胞（IEC）；但是，尚不清楚HO-1 / BMMSCs衍生的外泌体的机制和作用。在本研究中，我们旨在验证HO-1 / BMMSC和IEC-6细胞（IEC-6s）共培养系统的外泌体可以减少IEC-6s的凋亡并降低紧密连接蛋白的表达，透明带1，在炎症环境中。使用质谱，我们揭示了高迁移率族框3（HMGB3）和磷酸化的c-Jun NH2-末端激酶（JNK），在通过蛋白质组学分析鉴定出的差异丰富的蛋白质的影响下，在该机制中起着关键作用。进一步的研究表明，microRNA miR-200b，Hmgb3在这个生物过程中。功能性实验证实，miR-200b的过表达可以减少IEC-6s的炎症损伤，而细胞内miR-200b的敲低可以显着阻断HO-1 / BMMSCs外来体对IEC-6s的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的水平显着上调。在用HO-1 / BMMSCs处理的大鼠同种异体移植小肠移植模型中，我们证实了移植的小肠组织中miR-200b的水平显着增加，而HMGB3 / JNK的水平显着下调。总之，我们确定了HO-1 / BMMSCs的外泌体在减轻IECs的炎症损伤中起着重要作用。炎性损伤诱导IEC中的Hmgb3基因。降低的HMGB3水平可减轻炎症损伤。