C1q介导Wnt/β-catenin与IL-6信号交互在狼疮肾炎病理发生中的作用机制研究

Lupus nephritis (LN) is one of the most common complication and cause of death in patients with systemic lupus erythematosus (SLE), a better understanding of mechanisms of its pathogenesis is important for the diagnosis and regiment design for treatment of this disease in clinical settings. Our previous studies revealed the involvements of C1q complement, Wnt/β-catenin and interleukin-6 (IL-6) in the pathogenesis of LN, indicating a C1q-mediated interaction between Wnt/β-catenin and IL-) signaling in development of LN. This proposal thus aimed to explore the C1q-mediated cross-talk between Wnt/β-catenin and IL-6 signaling in the pathogenesis via an accomplishment of below three specific aims as following: (1) evaluating the concentration of proteins of Wnt/β-catenin and IL-6 signaling in renal tissues, sera and/or urines in SLE patients LN clinical, which will allow us to access a clinical relevance between these two signaling; (2) in vitro study to demonstrate the C1q-mediated cross-talk between Wnt/β-catenin and IL-6 signaling by stimulating glomerular cell lines and peripheral blood mononuclear cells (PBMCs) using immunoprecipitation complex isolated from human sera; (3) uncovering the pathogenic role and mechanism of cross-talk between Wnt/β-catenin and IL-6 by generating IL-6 gene deficient lupus nephritis of murine model to access pathological and dynamic changes of the expression of Wnt/β-catenin and IL-6 signaling molecules. An accomplishment of this study will lay a foundation for further investigations in identification of novel biomarkers and targets for the diagnosis and treatment of LN.

狼疮性肾炎（LN）是系统性红斑狼疮最为常见的合并症和死亡原因之一，致病机理的研究对LN诊断和治疗策略的制定有着重要的临床意义。我们前期研究发现补体C1q、Wnt/β-catenin和 白介素6(IL-6)信号都参与LN的临床病理发生过程。本项目将通过对下述内容的研究来探讨C1q介导的Wnt/β-catenin和IL-6信号交互作用在LN致病中的作用机制：(1) 检测 LN患者体液Wnt/β-catenin信号和IL-6含量，揭示它们在临床LN中的相关性；(2) 利用C1q和血清免疫沉淀复合物刺激肾小球细胞系和外周血单核细胞，体外分析C1q介导Wnt/β-catenin与IL-6信号交互作用；(3) 制备 IL-6基因缺陷狼疮小鼠肾炎模型体内探讨Wnt/β-catenin和IL-6信号交互作用在LN病理发生过程中的可能机制。本项目的完成将为临床LN的诊断标志和治疗靶标的深入研究提供理论依据。

狼疮性肾炎（LN）是系统性红斑狼疮最为常见的合并症和死亡原因之一。我们前期研究发现补体C1q、Wnt和白介素6（IL-6）信号都参与LN的临床病理发生过程，具体机制不明。因此，通过此项目研究我们深入探究了：1. 基于红斑狼疮患者临床标本的研究证实Wnt5a蛋白可能作为评估活动期SLE病人皮肤受损程度的生物学标志物。并且血浆和尿液Wnt5a阳性患者组皮肤红斑狼疮病面积和严重度指数（CLASI）活动性评分明显高于血浆和尿液Wnt5a阴性患者组。除此以外， IL-6可能作为临床诊断LN的危险因素之一，且血浆中IL-6联合临床实验室指标（抗dsDNA抗体、补体C4、抗U1RNP抗体）可提高临床诊断LN的特异度及敏感性。2. 细胞水平的研究结果证实：LN病人血浆刺激HGMC，可诱导其增殖及分泌炎症因子IL-6。同时，外源性增强IL-6和C1q高表达的LN病人血浆作用于HGMC可促进Wnt/β-catenin信号活性，而利用IL-6抗体中和IL-6后，IL-6联合LN病人血浆组，Wnt/β-catenin信号活性也随之降低。3. 动物实验研究结果证实：敲除MRL-Faslpr狼疮小鼠IL-6基因后，MRL-Faslpr狼疮小鼠相关疾病特征指标（肾脏组织病理、肾脏组织免疫复合物沉积、生存率、抗dsDNA抗体水平、血清中免疫复合物的水平、蛋白尿、脾脏大小及淋巴结大小等）明显降低。同时，免疫印迹、RT-PCR及免疫组化结果发现，与MRL-Faslpr狼疮小鼠相比较，IL-6缺陷的MRL-Faslpr狼疮小鼠肾脏组织Wnt/β-catenin信号的关键蛋白具有活性的β-catenin（ABC）、配体Wnt3a、抑制分子DKK1、胞核转录因子TCF-4、 LEF-1及CycliD1 均下调。基于过细胞、动物、人体三个层面的研究证实：C1q介导IL-6与Wnt信号之间的交互作用在狼疮肾炎病理发生中起着关键作用。IL-6和Wnt信号可作为治疗LN的新靶点。