Targeting renal inflammatory pathways of SLE nephritis in mouse and man

描述(由申请人提供)：这项提案是Davidson和Kretzler实验室的合作项目，反映了一系列基于人类和小鼠SLE肾炎基因发现的融合实验，以及基于这些研究结果产生的假设的一系列小鼠功能研究。该建议是基于这样一个中心假设，即SLE肾炎进展途径的分子标志物可以作为结果和治疗反应的预测因子。利用一种独特的小鼠系统性红斑狼疮肾炎缓解诱导模型，我们已经确定了两条主要的生理通路：相关疾病的发病和缓解。它们是：1)激活肾内皮细胞；2)激活肾巨噬细胞和树突状细胞，产生促炎细胞因子。部分签名与其他进行性小鼠肾脏疾病相同，这两个签名与在人类SLE肾活检中发现的签名显著重叠。我们进一步发现，在几种不同的小鼠SLE模型中，常驻肾巨噬细胞的激活是临床肾炎发病的一个标志，并与ITGAM上调有关，ITGAM是最近发现的一种赋予SLE风险的基因。目前的建议侧重于肾脏中巨噬细胞/树突状细胞的激活途径，以期确定可以作为治疗靶点的关键途径。我们将首先确定狼疮小鼠肾脏中活化的巨噬细胞/单核细胞的表型和来源，以及它们的前体是否可以在外周血中找到。然后，我们将描述激活的巨噬细胞和树突状细胞在肾脏和尿液沉渣中的功能。我们将结合免疫组织化学、流式细胞术、功能研究和基因表达谱来识别可能是严重程度/预后标志的基因，或者是疾病开始、缓解和复发的生物标志。对人类系统性红斑狼疮、肾脏活检和尿细胞球的平行研究将使我们能够确定可以在小鼠模型中进一步探索的途径。同时，在小鼠模型中确定的候选基因将在人类样本中使用服装阵列qRT-PCR方法进行评估。对人类和小鼠数据集进行更复杂的系统分析将有助于识别可以作为治疗靶点的关键信号转导和转录途径。我们的研究允许我们最大限度地利用大型数据集来磨练可能在SLE患者之间共享的途径。此外，我们计划为标准化的最先进的组织采购和银行业务建立我们的联盟，并通过复杂的基于网络的工具提供数据，以便与其他研究人员共享。 公共卫生相关性： 肾脏疾病是导致系统性红斑狼疮患者死亡和残疾的重要原因。目前的治疗方法疗效不佳，毒性大。由于SLE患者的肾脏疾病类型不同，我们将使用几种SLE肾炎的小鼠模型来更多地了解不同类型肾脏疾病的肾脏炎症和缓解的机制，并使用获得的数据来探索从人类SLE肾脏活检中获得的信息。我们将进行基因发现实验，以确定与肾脏疾病的不同阶段和治疗反应相关的新的基因表达模式。我们的研究应该帮助我们识别新的致病机制，为治疗干预找到新的靶点，并识别有助于预测结果和治疗反应的强大生物标记物。

DESCRIPTION (provided by applicant): This proposal is a collaborative venture from the Davidson and Kretzler laboratories that reflects a set of converging experiments based on gene discovery in human and murine SLE nephritis, and a set of functional studies in mice based on hypotheses generated as a result of these studies. The proposal is based on the central hypothesis that molecular markers of SLE nephritis progression pathways can serve as predictors of outcome and therapeutic response. Using a unique model of remission induction of murine SLE nephritis we have identified two main physiologic pathways are associated disease onset and remission. These are: 1) activation of the renal endothelium and 2) activation of renal macrophages and dendritic cells with production of pro-inflammatory cytokines. Part of the signature is shared with other progressive murine renal diseases and both signatures overlap significantly with those found in human SLE renal biopsies. We have further discovered that activation of resident renal macrophages is a hallmark of onset of clinical nephritis in several disparate murine SLE models and is associated with upregulation of ITGAM, a gene that has recently been found to confer SLE risk. The current proposal focuses on the activation pathways of macrophages/dendritic cells in the kidneys with a view to identifying key pathways that could be targeted therapeutically. We will first determine the phenotype and origins of activated macrophages/monocytes in murine lupus kidneys and whether their precursors can be found in the peripheral blood. We will then characterize the function of activated macrophages and dendritic cells in the kidneys and urine sediment. We will use a combination of immuno- histochemistry, flow cytometry, functional studies and gene expression profiling to identify genes that are putative severity/prognostic markers or that are biomarkers for disease onset, remission and relapse. Parallel studies in human SLE renal biopsies and urinary cell pellets will allow us to identify pathways that can further be explored functionally in the murine models. At the same time candidate genes identified in the murine models will be evaluated in the human samples using a costume array qRT-PCR approach. More sophisticated systems based analysis of the human and murine data sets will help identify key signal transduction and transcriptional pathways that can be targeted therapeutically. Our studies allow us to make maximal use of large data sets to hone in on pathways that are likely to be shared among SLE patients. In addition we plan to build our consortium for standardized state-of-the-art tissue procurement and banking and to make data available through sophisticated web based tools for sharing with other investigators. PUBLIC HEALTH RELEVANCE: Kidney disease is a significant cause of death and disability in patients with SLE. Current treatments have insufficient efficacy and high toxicity. Because SLE patients differ from each other with respect to the patterns of kidney disease we will use several mouse models of SLE nephritis to understand more about the mechanisms for kidney inflammation and remission in different types of kidney disease and use the data obtained to probe information obtained from human SLE kidney biopsies. We will perform gene discovery experiments to identify novel patterns of gene expression that are associated with the various stages of kidney disease and with responses to treatment. Our studies should help us identify new pathogenetic disease mechanisms, to find novel targets for therapeutic intervention and to identify robust biomarkers that will help predict outcomes and responses to therapy.