牙龈间充质干细胞通过IDO信号抑制移植物抗宿主病的机制研究

移植物抗宿主病(GVHD)是移植后的难治性并发症。近年来发现人牙龈间充质干细胞(GMSC)具有免疫调控功能。我们前期研究证实GMSC能通过增加调节性T细胞(Treg)来缓解小鼠关节炎。但GMSC能否用于治疗GVHD尚不清楚。我们预实验结果显示GMSC能延长异种GVHD小鼠存活期，并抑制T细胞增殖，阻断CD39及IDO信号逆转其作用。本项目拟进一步研究其作用机制。首先，观察GMSC是否通过调控Treg、Th1及Th17保护GVHD。然后，通过CD39 shRNA转染预处理GMSC或IDO抑制剂1-MT处理GVHD小鼠，明确GMSC的体内调控机制。慢病毒载体沉默或过表达CD39，活化或阻断腺苷信号处理GMSC，利用Western、PCR检测IDO表达，验证GMSC细胞的CD39-腺苷-IDO调控通路的存在。本项目将揭示GMSC抑制GVHD的作用机制，为临床应用GMSC治疗GVHD提供科学依据。

Graft-versus-host disease (GVHD) is intractable complications after organ transplantation. Recently, it has been reported that human gingival derived mesenchymal stem cells (GMSC) plays an important role in regulating immune reactions. We found that GMSC exerted a positive role in mouse model of arthritis partially via upregurating regulatory T cell (Treg). But it is still unknown about the effect and mechanism of GMSC on GVHD model. Our pre-experiment results showed that GMSC treatment significantly extended the survival of the xeno-graft versus-host disease (xeno-GVHD) model mice. We also found that the GMSC significantly inhibited the proliferation of human T lymphocytes proliferation in vitro, and it lost its suppression function while blocking CD39 and IDO signal. This project intends to further explore the specific molecular mechanism of the GMSC to treat GVHD. First, to observe if the Treg, Th1, Th17 were involved in the function of GMSC treatment in GVHD model. To investigate the mechanism of GMSC treated GVHD model in vivo, CD39 shRNA was transfected to GMSC before treatment. In another way, IDO inhibitor 1-MT was intraperitoneal injected to GMSC treated GVHD mice. To detect the regulatory pathways of CD39-adenosine-IDO in GMSC, we will use the lentiviral vector silencing or overexpressing CD39 molecules to treat GMSC, or activating or blocking the pathway of adenosine. In that circumstance IDO expression was verified via Western Blot, real time - PCR methods. This project aimed to reveal the GMSC function in GVHD model and its specific molecular mechanism. So that we might provide a scientific basis for the clinical application of the GMSC treatment of GVHD.