SLE患者BM-MSCs释放的exosomes通过Galectin-3调节B细胞异常激活的研究

Previous studies revealed BM-MSCs from SLE patients played an important role in immune dysregulation of B cells. In the preliminary experiments, we discovered that high-expressed Galectin-3 in exosomes of BM-MSCs from SLE patients, binding to BAFF-R, could promote abnormal B cell activation. Upon this, we hypothesized that BM-MSCs from SLE patients would release abnormal exosomes, in which the expression of Galectin-3 increased, and Galectin-3 binding to N-glycosylated BAFF-R expressed by B cell, would led to aberrant B-cell activation. To test our hypothesis, we conducted the following experiments: 1) We studied the effect of Galectin-3 in exosomes from BM-MSCs of SLE patients on B cell immune regulation. 2) On this basis, we analyzed the combination of Galectin-3 and BAFF-R, and their effects on abnormal B cell activation. 3) We investigated that the combination of Galectin-3 and N- glycosylated BAFF-R, and the effect on B cell immune regulation. 4) Finally, we explored the disease activity of MRL/lpr mice by intervening the combination of Galectin-3 and BAFF-R. This project provided the experimental basis to understand the mechanism of SLE BM-MSCs abnormality and the theoretical basis to seek new diagnosis and treatments of SLE.

前期研究发现SLE患者BM-MSCs对B细胞免疫调节异常。预实验发现SLE患者BM-MSCs exosomes中Galectin-3增高，且与BAFF-R结合，促进B细胞异常激活。据此提出SLE患者BM-MSCs释放的exosomes中增高的Galectin-3与N-糖基化修饰的BAFF-R结合，促进B细胞异常激活及SLE发生的假说。本课题拟首先分析SLE患者BM-MSCs exosomes中Galectin-3对B细胞激活的影响；接着分析Galectin-3与BAFF-R结合对B细胞激活的影响；还深入地分析BAFF-R N糖基化修饰对其与Galectin-3结合及B细胞异常激活的影响；最后分析干预Galectin-3与BAFF-R结合对MRL/lpr鼠疾病活动的影响。本研究结果为阐明BM-MSCs异常导致SLE发生的细胞及分子机制提供实验依据，对SLE的诊断及治疗有重要意义。

系统性红斑狼疮是一种累及多器官、多系统，严重危害患者身体健康和生活质量的自身免疫性疾病。先前的研究表明SLE患者的BM-MSCs对B细胞免疫应答失调主要通过非细胞间直接接触机制。本项目我们首先分离出BM-MSCs来源的exosomes，并鉴定成功，分析SLE组及正常组exosomes对B细胞激活的影响，接着分析SLE患者BM-MSCs exosomes中Galectin-3的表达差异，及差异表达的Galectin-3对B细胞增殖能力及细胞因子分泌等的影响；并进一步分析了BAFF-R与Galectin-3结合能力及其在BM-MSCs调节B细胞免疫异常中的作用，最后，在SLE动物模型MRL/lpr鼠中，我们探讨了SLE的BM-MSCs来源的exosomes对外周器官（脾脏、淋巴结）的B细胞免疫调节的影响。在发现骨髓炎症微环境可导致BM-MSCs衰老，衰老的BM-MSCs可出现免疫调节异常的基础上，项目组发现衰老的BM-MSCs释放的exosomes存在异常，其中的Galectin-3增多，其可结合B细胞表面N-糖基化修饰的BAFF-R，进而导致B细胞的异常激活，最终导致SLE的发生。本研究将进一步丰富SLE是一种MSCs病的理论，发现并阐明SLE患者BM-MSCs衰老过程中exosomes释放导致疾病发生的原因及可能机制，对于研究SLE的发病机制及寻找新的治疗方案具有极为重要的意义。项目经费按照预算计划使用，共发表论文20篇。研究结果多次在国内外会议宣讲，共培养研究生5名。