miR-326调控Ets-1在系统性红斑狼疮发病中作用的机制研究

Systemic lupus erythematosus (SLE) is a clinically heterogeneous and progressive autoimmune disease with multiple organ involvement. The exact pathogenesis of SLE is still not clear. But it was all known that both T and B lymphocyte abnormalities contributed to the pathogenesis of SLE. Recent studies have found that the transcription factor Ets-1 could suppress the differentiation of B cells and Th17 cells, and affect the stable expression of Foxp3 in Treg cells，the deficiency of Ets-1 might involve in the pathogenesis of SLE. At present, miRNAs have been confirmed that paly an important role in autoimmune diseases by regulating the gene expression. Theoretically, microRNA may be involved in the pathogenesis of SLE by regulating the expression of Ets-1. So, deep exploration of this study will be helpful to clarify the pathogenesis of SLE, which is of great significance. Our previous studies have found that miR-326 was elevated and mRNA expression of Ets-1 was decreased in SLE patients. Therefore, on the basis of previous work, we will use case control study, in vitro studies and animal experiments to explore the experiment listed as follows. The expression of Ets-1 will be observed when we stimulate or suppress the expression of miR-326. Differentiation of B cells and Th17 cells as well as the expression of Foxp3 will also be observed. This research will clarify that miR-326 may play an important role in pathogenesis of SLE through regulating Ets-1 expression. It will provide a scientific basis for the discovery of new therapeutic targets for SLE.

系统性红斑狼疮（SLE）发病机制尚不清楚，T、B淋巴细胞异常参与了SLE的发病。近期研究发现转录因子Ets-1对B和Th17细胞分化、Treg细胞Foxp3表达有影响，其产生不足可能与SLE发病有关；而目前microRNA通过调控基因表达参与自身免疫性疾病的作用日益显著。理论上而言，microRNA可能通过调控Ets-1参与SLE发病，深入探索该研究将对阐明SLE发病机制具有重要意义。而本课题组前期研究发现SLE患者miR-326升高、Ets-1的mRNA降低，二者呈显著负相关。因此，本项目拟在前期研究基础上从病例对照、离体研究和动物实验三个层面，采用促进和抑制miR-326表达的不同手段、观察其对Ets-1表达以及B和Th17细胞分化、Treg细胞Foxp3表达三条路径的影响，全方位多层次阐明miR-326调控Ets-1参与SLE发病的关键作用机制，为SLE的治疗提供新靶点。

系统性红斑狼疮（SLE）是一种以B和T细胞免疫失调为特征的自身免疫病。转录因子Ets-1是B和Th17细胞分化的负性调节因子。研究报道Ets-1表达异常与SLE发病有关。研究证实miR-326过表达可抑制其靶基因Ets-1表达。因而提出miR-326可能通过抑制Ets-1，影响B和Th17细胞分化参与SLE发病的假说。主要研究内容：（1）病例对照研究：观察SLE患者miR-326表达与Ets-1表达、B和Th17细胞分化以及临床特征的关联；（2）离体实验：通过促进或抑制SLE患者外周naïve T细胞miR-326表达，观察Ets-1表达以及B和Th17细胞分化的变化；（3）动物实验：促进或抑制MRL/lpr狼疮模型鼠miR-326表达，通过病理和免疫学指标观察miR-326变化对疾病进程的影响。研究结果：（1）SLE活动期患者外周血B细胞中Ets-1表达减少，miR-326表达增加，两者表达成负相关(r=-0.667)，且Th17细胞比例和CD19-CD138+浆细胞比例均显著高于健康对照（0.78±0.21 % vs 0.49±0.28 %，p=0.004; 0.465±0.185% vs 0.198±0.118%，p=0.005）。此外，SLE患者miR-326高表达与疾病严重程度相关，其中有浆膜腔积液患者Treg细胞中miR-326表达高于无此临床症状者。（2）增加或减少新发SLE患者naïveT细胞miR-326表达可导致Ets-1 mRNA水平的降低或增加；miR-326过表达的naïve T细胞经Th17极化后较对照组产生更多的Th17细胞，但差异均无统计学意义（p<0.05）。（3）miR-326过表达鼠脾脏浆母细胞和Th17细胞比率均高于miR-326抑制鼠（7.980±0.561 % vs 4.650 ± 0.344 %，p=0.0001；0.940 ± 0.123 % vs 0.609 ± 0.043 % , p=0.002）；miR-326过表达鼠血清IL-17、IL-6和抗双链DNA抗体水平均高于miR-326抑制鼠（p=0.02，0.046，0.024）。MiR-326过表达可增加小鼠肾脏IgG沉积，加重肾小球损伤。科学意义：本研究证实miR-326可通过抑制Ets-1，促进B和Th17细胞分化参与SLE进展。为SLE治疗提供了新靶点。