MiR-125b调控系统性红斑狼疮T细胞作用机制及雷公藤甲素干预研究

MicroRNAs (miRNAs) are known to regulate several cellular processes,including differentiation, cell cycle, apoptosis, and immune functions.Among numerous immunologic research present in lupus patients, T cell is thought to play a pivotal role in pathogenesis.T-cell cytokines affect B cells by stimulating cell division, switching antibody production and promoting a change in the molecular sequence of the secreted antibody so that it binds more strongly to the driving antigen.Thus, T-cell makes possible the production of high-affinity IgG autoantibodies. These kinds of antibodies are closely linked to tissue damage in lupus.Our previous studies have shown that the expression of miR-125b was significantly lower in patients with lupus compared to controls. Further analysis showed that the down-regulation of miR-125b, mainly in T cells, was negatively correlated with lupus nephritis. We also confirmed that ETS1 are target genes of miR-125b using a dual-luciferase reporter transfection assay. Triptolide has been shown to be effective in treating lupus nephritis.However, the molecular mechanisms remains largely unknown.In this study, we identify the underexpression of miR-125b in patients with SLE and further demonstrate an association between miR-125b levels and overactivation of the ETS1 pathway and explore the potential molecular mechanisms.And we investigate the effects of triptolide activity on this pathway，uncover a new mechanism between triptolide and microRNA.The findings will reveal the relevance of miRNA genes in the biologic and clinical behavior of SLE and provide potential novel strategies for therapeutic intervention.

MicroRNA参与生物体的生长、发育、凋亡等的调控，在免疫细胞的功能调节中发挥重要作用。T细胞的功能紊乱在系统性红斑狼疮（SLE）发病中起着主要作用，异常的T淋巴细胞产生过多的细胞因子刺激B淋巴细胞，导致B淋巴细胞高度活化，产生大量自身抗体导致SLE的发病。项目申请人前期工作发现miR-125b在SLE患者中表达水平明显减低，在T细胞中表达差异最为显著，且与SLE肾脏受累相关，初步研究发现ETS1为mir-125b作用的靶基因。雷公藤甲素治疗SLE的药理机制尚不清楚，可能与雷公藤甲素广泛抑制基因转录相关，但雷公藤甲素作用于microRNA的研究未见报道。该课题在前期工作基础上深入探讨miR-125b对SLE患者T细胞的功能调节，提出可能的分子机制及信号通路。并以该通路为基础研究雷公藤甲素对该通路的影响，进而提出雷公藤甲素干预microRNA的机制，以期探寻SLE发病的新机制和防治新策略。

MicroRNAs (miRNAs)参与调控多种细胞过程包括细胞分化、细胞周期、细胞凋亡和免疫功能等。T淋巴细胞功能紊乱在系统性红斑狼疮（SLE）发病中起着主要作用，异常的T淋巴细胞产生过多的细胞因子能够通过促进B淋巴细胞的细胞分裂和影响抗体产生导致B淋巴细胞高度活化，产生大量自身抗体导致SLE的发病。项目申请人前期工作发现miR-125b在SLE患者外周血T淋巴细胞尤其是狼疮肾炎患者外周血T淋巴细胞中表达水平明显降低。该课题在前期工作基础上进一步研究发现：1.miR-125b抑制SLE患者外周血T淋巴细胞增殖、促进细胞凋亡。2.双荧光素酶报告系统证实转录因子STAT3为miR-125b靶基因，过表达miR-125b可导致SLE患者T淋巴细胞中STAT3表达减低，IL-6、IFN-γ表达减低。3.雷公藤甲素（TPL)抑制SLE患者T淋巴细胞增殖、促进细胞凋亡。4.雷公藤甲素作用于SLE患者T淋巴细胞可使miR-125b表达量增高，STAT3蛋白水平降低。5.初步研究发现miR-125b在狼疮肾炎患者血清及肾组织中表达增高，STAT3在狼疮肾炎患者血清及肾组织中表达减低。根据以上实验结果，我们认为miR-125b可能通过作用于转录因子STAT3引起IL-6、IFN-γ表达水平的变化从而参与SLE致病过程；雷公藤甲素可能通过作用于SLE患者T淋巴细胞促进miR-125b的表达发挥治疗SLE的作用；miR-125b及STAT3在狼疮肾炎患者T淋巴细胞及血清中存在差异表达，在肾组织可能存在差异表达，提示其在狼疮患者发病机制中可能发挥重要作用，并可能成为狼疮肾炎检测的新的生物学标记物；miR-125b参与调控T淋巴细胞增殖凋亡，其具体机制有待进一步探讨。