增加归巢能力对羊膜间充质干细胞防治急性移植物抗宿主病的影响研究

Prevention and treatment of acute graft versus host disease (aGVHD) is of great significance to improve the success rate of hematopoietic stem cell transplantation (HSCT) and improve the quality of life of patients. Mesenchyme stem cells (MSC) derived from bone marrow have been shown to be effective in preventing and treating aGVHD. However, their source, quantity, amplification and differentiation ability are limited. The human amniotic membrane is a highly abundant and readily available tissue. Amniotic MSC (AMSC) have been proposed as good candidates to be used in cell therapy or regenerative medicine to treat damaged or diseased tissues. We have shown AMSC can inhibit the PHA-induced allogeneic peripheral blood lymphocytes transformation and play a negative regulatory role in allogeneic immune response. This study is designed to evaluate the effects of AMSC on the prevention and treatment of aGVHD, and to observe the influences of enhancing the homing of AMSC by regulating SDF-1/ CXCR4 axis on the prevention and treatment of aGVHD in NSG mice. Some valuable informations may be provided to good advantage for modulating AMSC in the clinical setting, particularly for enhancing the effectiveness of HSCT.

防治急性移植物抗宿主病（aGVHD）对提高造血干细胞移植（HSCT）成功率、改善患者生存质量具有重要意义。已经证实骨髓间充质干细胞（mesenchymal stem cells，MSC）对防治aGVHD有效，但其来源、数量、扩增和分化能力有限，使研究和应用受到限制。羊膜MSC(AMSC)来源丰富、增殖迅速、分离纯化方法简单，可能成为一种更加理想的MSC新来源。前期我们已证实AMSC体外具有与骨髓MSC相似的多向分化潜能、支持造血作用及免疫特性，并且通过调节SDF-1/CXCR4轴能促进AMSC向骨髓归巢。本研究旨在探索应用AMSC预防和治疗aGVHD，并拟观察增强依赖SDF-1/CXCR4轴的归巢作用对AMSC预防和治疗aGVHD所产生的影响，为AMSC临床应用奠定基础，并希望为临床提高HSCT成功率提供新策略。

防治急性移植物抗宿主病（aGVHD）对提高造血干细胞移植（HSCT）成功率、改善患者生存质量具有重要意义。已经证实骨髓间充质干细胞（MSC）对防治aGVHD有效，但其来源、数量、扩增和分化能力有限，使研究和应用受到限制，且其免疫调节功能的具体调控机制尚缺乏进一步研究。羊膜MSC(AMSC)来源丰富、增殖迅速、分离纯化方法简单，可能成为一种更加理想的MSC新来源。本项目成功建立人源细胞-NPG小鼠aGVHD模型，证实输注人源AMSC能够明显减轻aGVHD临床表现，改善受体靶器官的病理损伤，延长小鼠生存。同时发现AEC条件培养基体外培养促进AMSC归巢，并很好地保存了AMSC的免疫调节功能。在此基础上进一步对其免疫调节调控机制进行探讨，采用shRNA技术特异性敲低AMSC中的肝激酶B1（Lkb1）表达以及利用基因敲除获得树突状细胞（DC）特异性Lkb1敲除小鼠，发现AMSC中Lkb1的表达对维持AMSC的自我更新及其对T细胞的免疫调节、维持机体的免疫平衡有重要作用；体内Treg细胞的丰度和免疫抑制的程度受DC中Lkb1动态调控。这为进一步操纵调控MSC免疫调节功能提供了重要的生物学信息和可能的途径，可能为诸如GVHD、自身免疫性疾病等的临床治疗提供新策略。