Abstract：
Mesenchymal stem cells (MSCs) reveal multifaceted immunoregulatory properties, which can be applied for diverse refractory and recurrent disease treatment including acute graft-versus-host disease (aGVHD). Distinguishing from MSCs with considerable challenges before clinical application, MSCs-derived exosomes (MSC-Exos) are cell-free microvesicles with therapeutic ingredients and serve as advantageous alternatives for ameliorating the outcomes of aGVHD. MSC-Exos were enriched and identified by western blotting analysis, NanoSight, and transmission electron microscopy (TEM). Bone marrow-derived MSCs (denoted as MSCs) and exosomes (denoted as MSC-Exos) were infused into the aGVHD SD-Wister rat model via tail vein, and variations in general growth and survival of rats were observed. The level of inflammatory factors in serum was quantized by enzyme-linked immunosorbent assay (ELISA). The pathological conditions of the liver and intestine of rats were observed by frozen sectioning. The ratios of CD4+/CD8+ and Treg cell proportions in peripheral blood, together with the autophagy in the spleen and thymus, were analyzed by flow cytometry. After treatment with MSC-Exos, the survival time of aGVHD rats was prolonged, the clinical manifestations of aGVHD in rats were improved, whereas the pathological damage of aGVHD in the liver and intestine was reduced. According to ELISA, we found that MSC-Exos revealed ameliorative effect upon aGVHD inflammation (e.g., TNF-α, IL-2, INF-γ, IL-4, and TGF-β) compared to the MSC group. After MSC-Exo treatment, the ratio of Treg cells in peripheral blood was increased, whereas the ratio of CD4+/CD8+ in peripheral blood and the autophagy in the spleen and thymus was decreased. MSC-Exos effectively suppressed the activation of immune cells and the manifestation of the inflammatory response in the aGVHD rat model. Our data would supply new references for MSC-Exo-based \"cell-free\" biotherapy for aGVHD in future.
摘要：
间充质干细胞（MSCs）揭示了多方面的免疫调节特性，可用于多种难治性和复发性疾病的治疗，包括急性移植物抗宿主病（aGVHD）。区别于临床应用前面临相当大挑战的MSCs，MSC衍生的外泌体(MSC-Exos)是具有治疗成分的无细胞微泡,并且用作改善aGVHD结果的有利替代方案。通过蛋白质印迹分析富集和鉴定MSC-Exos，NanoSight,和透射电子显微镜（TEM）。通过尾静脉将骨髓来源的MSCs（表示为MSCs）和外泌体（表示为MSC-Exos）注入aGVHDSD-Wister大鼠模型，并观察到大鼠总体生长和存活的变化。通过酶联免疫吸附试验（ELISA）量化血清中的炎症因子水平。采用冰冻切片法观察大鼠肝脏和肠道的病理情况。外周血中CD4+/CD8+和Treg细胞比例，以及脾脏和胸腺中的自噬，通过流式细胞术进行分析。用MSC-Exos治疗后，aGVHD大鼠的存活时间延长,大鼠aGVHD的临床表现得到改善,而肝脏和肠道中aGVHD的病理损伤减轻。根据ELISA,我们发现MSC-Exos显示出对aGVHD炎症的改善作用(例如，TNF-α,IL-2,INF-γ,IL-4和TGF-β）与MSC组相比。MSC-Exo治疗后，外周血中Treg细胞的比例增加，而外周血中CD4+/CD8+的比例以及脾和胸腺中的自噬降低。MSC-Exos有效抑制aGVHD大鼠模型中免疫细胞的活化和炎症反应的表现。我们的数据将为将来基于MSC-Exo的“无细胞”生物治疗aGVHD提供新的参考。
