miRNA146a调控NLRP3炎性体在SLE患者BM-MSCs免疫调节异常中的作用及机制研究

Previous studies of our research group revealed that the immunoregulation of senescent BM-MSCs from SLE patients was abnormal, which participated in the development of SLE. However, the mechanism remained uncertain. In the preliminary experiments, we discovered the high expression of inflammation factors, especially IL-1β in the culture medium of the BM-MSCs from SLE patients, which effected the regulatory T cell proliferation. The secretion of IL-1β was regulated by NLRP3 inflammasome, and the result showed the key molecular NLRP3 was increased significantly in the BM-MSCs from SLE patients. Further study found the expression of miR146a reduced observably in SLE BM-MSCs. Bioinformatics analysis indicated that NLRP3 may be the target gene of miR146a. Upon this, we proposed the hypothesis that the lower expression of miR146a promoted IL-1β secretion by activating the NLRP3 inflammasome in the BM-MSCs from SLE patients, which eventually leading to the immune dysregulation. Next, we will verify that whether the NLRP3 is the direct target gene of miR146a and whether IL-1β inhibited by miR146a can influence the immunoregulation of BM-MSCs in SLE patients. And we also will explore the effect in animal models by transplanting treated BM-MSCs. This project provided the experimental basis to understand the mechanism of SLE BM-MSCs immune dysregulation, which aim to seek new treatments of SLE.

前期研究已发现衰老的SLE患者BM-MSCs免疫调节存在异常，参与狼疮发生发展，但机制不明。课题组预实验提示SLE患者BM-MSCs培养基中IL-1β显著增多且影响Treg细胞增殖。IL-1β分泌主要受NLRP3炎性体调控，其关键分子NLRP3在SLE患者BM-MSCs中显著上调，进一步研究发现miR146a在其中低表达，同时生物信息学预测提示NLRP3为miR146a的靶基因。据此提出低表达的miR146a通过激活NLRP3炎性体促进SLE患者BM-MSCs IL-1β分泌，导致其免疫调节异常的假说。本项目拟进一步证实NLRP3是否为miR146a的直接靶基因，miR146a是否通过抑制IL-1β分泌影响SLE患者BM-MSCs免疫调节，同时在动物模型内观察干预上述机制后BM-MSCs移植的疗效。本研究将深入阐明SLE患者BM-MSCs免疫调节异常的机制，旨在寻求SLE治疗的新方法。

系统性红斑狼疮（SLE）患者骨髓间充质干细胞（BMSCs）存在分泌细胞因子及免疫调节异常。含NLR家族Pyrin域蛋白3(NLRP3)炎性体在SLE的发生发展中扮演重要角色。本课题旨在探讨miRNA是否参与了SLE-BMSCs中NLRP3的调节。研究结果表明SLE患者血清中IFN-α、IL-6、IL-18、IL-12、IL-13和IL-1β水平明显升高。NLRP3炎性小体在SLE-BMSC中高表达。let-7f-5p与NLRP3靶向相关，可抑制其表达。NLRP3下调或let-7f-5p上调均可抑制IL-1β的产生和NLRP3炎性体的表达。同时通过恢复NLRP3表达显著消弱了过表达let-7f-5p介导的抗炎效果。此外，在体内实验中慢病毒转染后上调let-7f-5p的SLE BMSCs 通过抑制NLRP3表达而改善MRL/lpr 鼠的炎症反应。最后，我们的研究表明，高表达的let-7f-5p通过针对NLRP3来缓解SLE-BMSC的至少部分炎症，该课题旨在强调let-7f-5p是SLE治疗的新有前途的治疗策略。