Targeting renal inflammatory pathways of SLE nephritis in mouse and man

描述（由申请人提供）：该提案是Davidson和Kretzler实验室的合作项目，反映了一组基于人类和小鼠SLE肾炎基因发现的聚合实验，以及一组基于这些研究结果产生的假设的小鼠功能研究。该建议基于SLE肾炎进展途径的分子标记物可以作为预后和治疗反应的预测因子的中心假设。利用一种独特的小鼠SLE肾炎缓解诱导模型，我们已经确定了两种主要的生理途径，即与疾病发作和缓解相关。它们是：1)肾内皮的激活和2)肾巨噬细胞和树突状细胞的激活，产生促炎细胞因子。部分特征与其他进行性小鼠肾脏疾病共享，这两个特征与人类SLE肾脏活检中发现的特征显著重叠。我们进一步发现，在几种不同的SLE小鼠模型中，常驻肾巨噬细胞的激活是临床肾炎发病的一个标志，并且与ITGAM的上调有关，ITGAM是一种最近被发现与SLE风险相关的基因。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，以确定可靶向治疗的关键途径。我们将首先确定小鼠狼疮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，我们将描述肾脏和尿液沉积物中活化的巨噬细胞和树突状细胞的功能。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/预后标志物或疾病发病、缓解和复发的生物标志物的基因。对人类SLE肾活检和尿细胞颗粒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功能的途径。同时，在小鼠模型中鉴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。基于人类和小鼠数据集分析的更复杂的系统将有助于确定关键的信号转导和转录途径，从而可以靶向治疗。我们的研究使我们能够最大限度地利用大型数据集来研究可能在SLE患者中共享的途径。此外，我们计划建立标准化的最先进的组织采购和银行联盟，并通过复杂的基于网络的工具提供数据，以便与其他研究者共享。

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.