TLR4异常激活导致BM-MSCs衰老在SLE发生中的作用

Previous studies of our research group revealed the senescence of BM-MSCs from SLE patients, which participated in the development of SLE. However, the mechanism of the senescence remained uncertain. In the preliminary experiments, we discovered the high expression of inflammation factors, such as HMGB-1 in the supernate of SLE patients' bone marrow, the abnormal activation of TLR4 signal transduction in the BM-MSCs from SLE patients, and the distinctively low expression of the mir146a upon TLR4 pathway. Upon this, we proposed the hypothesis that HMGB-1 triggered the senescence of BM-MSCs from SLE patients through the activation of TLR4 signal transduction, and mir146a participated in the process through the inhibition of TLR4 signal transduction. To test our hypothesis, we conducted the following experiments: 1)We studied the correlation of the senescence with the abormal expression of TLR4 in the BM-MSCs from SLE patients. 2) On this basis, we analyzed the combination of HMGB-1and TLR4, the regulation of mir146a upon TLR4 signal transduction, and their effects on the BM-MSCs senescence and the immune dysfunction.3)Finally, we explored the effect in animal models by transplanting treated BM-MSCs. This project provided the experimental basis to understand the mechanism of SLE BM-MSCs senescence and the theoretical basis to seek new treatments of SLE.

课题组前期研究表明SLE患者BM-MSCs是衰老的MSCs，参与狼疮发生发展，但衰老原因不明。预实验发现SLE患者骨髓上清液中HMGB-1等炎性因子高表达；SLE患者BM-MSCs内TLR4信号转导异常活化，作用于TLR4通路的mir146a显著低表达。据此提出HMGB-1通过激活TLR4信号转导导致SLE患者BM-MSCs衰老；mir146a通过调节TLR4信号转导参与其中的假说。课题组拟首先分析SLE患者BM-MSCs中TLR4表达异常与衰老的关系；在此基础上分析HMGB-1与TLR4结合及mir146a对TLR4信号转导调节在BM-MSCs衰老及免疫失能中的作用；最后在SLE动物模型内观察干预上述机制后BM-MSCs移植的疗效。本课题为阐明SLE患者BM-MSCs衰老机制提供实验基础，为寻找SLE治疗的新方法提供理论依据。

系统性红斑狼疮（SLE）是一种多系统、多器官受累，严重影响患者生活质量和寿命的自身免疫性疾病。先前研究表明骨髓间充质干细胞（BM-MSCs）的衰老参与SLE的发生发展。炎症微环境在细胞衰老的发生过程中具有十分重要的作用。本研究首先运用蛋白组学分析SLE患者及正常人骨髓中炎症因子的表达情况，并运用ELISA进一步验证。接着检测骨髓上清液对BM-MSCs衰老的作用，并确定炎症因子HMGB1在其中的作用。接着分析HMGB1对BM-MSCs衰老的作用并进一步明确TLR4/NF-κB信号通路与BM-MSCs衰老的关系，并运用丙酮酸乙酯(Ethyl pyruvate，HMGB1抑制剂)治疗狼疮动物模型验证上述结果。最后，在此基础上分析miR146a如何介导TLR4信号通路而导致SLE患者BM-MSCs衰老和免疫失能。本研究进一步阐明炎症微环境在BM-MSCs衰老中的作用，深入探讨SLE患者BM-MSCs衰老的原因及可能机制，对于BM-MSCs异基因移植复发的机制研究提供了新的思路，对于研究SLE的发病机制及靶向治疗SLE具有重要意义。项目经费按照预算计划使用，共发表23篇SCI期刊收录论文，1篇SCI修回，1篇SCI已投稿。研究结果多次在国内外会议宣讲，共培养研究生4名。