MIF影响SLE激素抵抗的上游调控机制及其潜在靶点在鼠模型上的靶向研究

Some patients with systemic lupus erythematosus (SLE) exhibit clinical resistance to glucocoticoid therapy,which constructs an obstacle to the remission of SLE.In our previous work,we have revealed that macrophage migration inhibitory factor(MIF) paly a key role in steroid sensitivity in SLE and it works through impacts on the NF-κB/IκB signaling cascade.These observations can be of significance in elucidating the underlying mechanisms behind steroid resistance. Based on the these observations,we will further explore the upstream regulatory mechanisms about MIF affecting glucocorticoid sensitivity in SLE patients.There is evidence that annexin-1 ,an upstream protein, can exert endogeneous antiinflammatory effects via regulating MIF and also mediates the antiinflammatory actions of dexamethasone.Also,the results from some recent studies showed that MIF gene promoter polymorphisms correlate with MIF expression.In our study,we will explore the role of annexin-1 in the interactions between MIF and glucocorticoid in SLE first time.We aim to find that the down-regulation of annexin-1 expression promotes the synthesis of MIF and then upregulates the activation of NF-κB/IκB signaling transduction pathway and to some extent glucocorticoid resistance.In addition,we will also investigate whether the MIF gene promoter polymorphisms correlates with glucocorticoid sensitivity in steroid-sensitive and steroid-resistant SLE patients.And, we will try some target therapies based on MRL/lpr and MRL/lpr (MIF knocking in)mice by means of anti-MIF and annexin-1 antagonist. The studies will tell us if annexin-1 and MIF can be a promising upstream target affecting glucocorticoid sensitivity and if MIF alleles can be regarded as a biomarker in evaluating the response to glucocorticoid therapy in patients with SLE.

SLE合并激素抵抗由于治疗困难而严重影响患者预后。我们已发现巨噬细胞游走抑制因子(MIF)可通过调控NF-κB/IκB信号通路参与SLE患者的激素抵抗发生机制，并证实MIF影响SLE患者的激素敏感性(发表于Arthritis Research & Therapy)。近来有依据表明膜联蛋白-1(annexin-1)是MIF的重要上游信号蛋白且与激素抵抗有关,此外，研究也显示MIF基因启动子区多态性可影响MIF表达。故本研究拟通过以下三方面：1. annexin-1与MIF-NF-κB/IκB调控通路的关系；2. SLE患者对激素不同应答的遗传学原因；3. MRL/lpr及MIF转基因MRL/lpr小鼠实体模拟靶向治疗的研究，以期能深入诠释SLE激素抵抗发生机制，并探讨annexin-1及MIF作为影响激素敏感性的药物靶点的可能性及挖掘MIF等位基因作为临床预测激素治疗反应的生物标志物的潜力。

目的：探究MIF在系统性红斑狼疮中的组织及细胞表达定位，上下游调控分子，共同参与的发病机制环节，以及在风湿病诊疗价值中的潜在价值。.方法：1.通过流式细胞学、Western Blot 、荧光定量PCR、及免疫组化技术研究MIF在外周血细胞亚群以及肾脏组织中的表达水平及定位，分析病例对照表达差异及临床相关性；.2.通过生物信息学、荧光素酶报告基因系统、体外转染、Tagman探针、siRNA基因沉默等技术对靶向调控MIF的miRNA进行筛选，并研究其表达及功能；3.使用SLE肾脏组织及正常对照肾组织中检测CD44mRNA、蛋白表达水平及临床相关性；使用原代肾小管上皮细胞、MIF敲减细胞株及transwell模型探究MIF及CD44在炎症通路的激活和炎症细胞浸润机制。.结果：1.MIF在狼疮患者外周血及肾脏组织中显著升高，其表达与肾脏受累与否及严重程度相关，狼疮患者肾脏中阳性定位主要位于肾小管上皮细胞。.2.miR-152在狼疮患者肾组织中显著上调，其表达与肾脏慢性指数及MIF的表达负相关，荧光素酶报告基因及体外细胞学证实其靶向调控MIF的表达，miR-152抑制COL1A1表达；而MIF促进COL1A1表达；狼疮患者肾组织中COL1A1高于正常组织，与MIF表达正相关，与miR-152表达负相关。.3. CD44在狼疮患者肾组织中显著升高，其表达与肾脏活动性指数正相关；MIF上调CD44表达，siRNA抑制MIF表达抑制多种炎症因子对CD44诱导；MIF及CD44促进U937细胞向原代肾小管上皮细胞趋化。.结论： MIF在系统性红斑狼疮肾脏受累机制中处于中心位置，MIF可受miR-152调控参与狼疮肾炎的纤维化进程，MIF调控CD44参与狼疮肾炎的炎症激活通路及炎性细胞的浸润