Interplay of Innate and Adaptive Immunity in Lupus Pathogenesis

先天免疫和适应性免疫在狼疮发病机制中的相互作用

• 批准号: 8470539
• 负责人: Michelle L. Hermiston
• 金额: $ 35.94万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-06-01 至 2015-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8470539
• 关键词: Adjuvant; Amino Acid Substitution; Antibodies; Antigen-Antibody Complex; Autoantibodies; Autoimmune Diseases; Autoimmunity; B-Lymphocytes; Backcrossings; Biochemical; Bone Marrow; Candidate Disease Gene; Cells; Cessation of life; Chimera organism; Chromosomes, Human, Pair 9; Chronic; Clinical; Complex; Computer Simulation; Congenic Mice; DNA; Data; Development; Disease; Genes; Genetic; Genetic Polymorphism; Genetic Screening; Glomerulonephritis; Goals; Homeostasis; Human; Hybrids; Immune; Immune System Diseases; Immune system; Inbred BALB C Mice; Individual; Leucine-Rich Repeat; Ligand Binding Domain; Ligands; Lupus; Lymphoproliferative Disorders; Malignant lymphoid neoplasm; Maps; Mediating; Modeling; Molecular; Molecular Models; Mus; Mutation; Natural Immunity; Organ; PTPRC gene; Pathogenesis; Patients; Peripheral; Phenotype; Phosphoric Monoester Hydrolases; Process; Production; Relative (related person); Research; Signal Pathway; Signal Transduction; System; Systemic Lupus Erythematosus; T-Lymphocyte; TLR9 gene; Testing; Therapeutic Intervention; Toll-like receptors; Vaccines; adaptive immunity; anti-dsDNA antibodies; arm; autoreactivity; defined contribution; ds-DNA; insight; interest; molecular modeling; mouse model; novel; premature; programs; public health relevance; receptor; response; src-Family Kinases; trafficking

DESCRIPTION (provided by applicant): Systemic Lupus Erythematosus (SLE) is a complex, polygenic disease. The delayed onset and variable pentetrance of SLE support the hypothesis that disease pathogenesis is a multi-step process. The highly variable clinical presentation of human SLE makes the study of this process difficult in patients. Here, we take advantage of a tractable and simplified genetic system, the CD45E613R mouse, to interrogate SLE pathogenesis. These mice express a single amino acid substitution that results in constitutive CD45 phosphatase activity. Mirroring the variable presentation of human SLE, the CD45E613R phenotype is extremely sensitive to genetic background. On a hybrid 129-C57Bl/6 (B6) background, CD45E613R mice develop anti-dsDNA antibodies and immune complex-mediated glomerulonephritis (GN). However, on a B6 genetic background mice lack autoantibodies despite biochemical hyper-responsiveness to receptor stimulation while BALB/c CD45E613R mice develop high-titer anti-dsDNA but no GN. We have taken advantage of the genetic separation of cellular hyper-responsiveness, autoantibody production, and end-organ damage to search for genetic modifiers required for disease. Here, we focus on the mechanisms governing the first two steps in SLE pathogenesis: Loss of tolerance to self and peripheral amplification of this autoreactivity. The goal of Aim 1 is to define the contributions of two novel loci we recently identified, Wam1 and Wam2, to autoantibody production. Congenic mice will be generated to test how these loci regulate the threshold for tolerance in the context of hyperactive CD45 phosphatase activity. In Aim 2, we evaluate the contributions of a promising candidate gene in Wam1, Toll Like Receptor (TLR) 9, to disease pathogenesis. Molecular modeling of the TLR9 polymorphisms indicate they map to leucine rich repeats in the DNA ligand binding domain. Our preliminary data indicate differential responses to TLR9 stimulation between B6 and BALB/c mice. These differences are further modulated by the CD45E613R mutation, indicating a novel interaction between CD45 and TLR9 signaling networks. We will use genetic and mixed bone-marrow chimera approaches to define the impact of TLR9 on autoantibody production and identify the cellular compartments in which it must function in CD45E613R mice. The focus of Aim 3 is to interrogate the cellular and molecular mechanisms by which the TLR9 polymorphisms and the CD45E613R mutation regulate tolerance. We will evaluate whether the observed differences are due to altered interaction with ligand, perturbations in intracellular trafficking, and/or altered signal transduction networks. Results of these studies will not only help elucidate the mechanisms governing tolerance, but should provide new insights into how the adaptive and innate arms of the immune system interact in systemic autoimmunity. This is a topic of significant importance in the pathogenesis of autoimmune disease in humans and has broad impact given the growing interest in targeting TLRs in the treatment of autoimmune disease and as an adjuvant in vaccine strategies.

描述（由申请人提供）：系统性红斑狼疮（SLE）是一种复杂的多基因疾病。SLE的迟发性和可变渗透性支持了疾病发病是一个多步骤过程的假设。人类SLE的高度可变的临床表现使得在患者中研究这一过程变得困难。在这里，我们利用一个易于处理和简化的遗传系统，CD45E613R小鼠，来探究SLE的发病机制。这些小鼠表达单个氨基酸替代，导致组成型CD45磷酸酶活性。反映了人类SLE的可变表现，CD45E613R表型对遗传背景极其敏感。在129-C57Bl/6 （B6）杂交背景下，CD45E613R小鼠产生抗dsdna抗体和免疫复合物介导的肾小球肾炎（GN）。然而，在B6遗传背景下，小鼠缺乏自身抗体，尽管对受体刺激的生化高反应性，而BALB/c CD45E613R小鼠产生高滴度的抗dsdna，但没有GN。我们利用细胞超反应性、自身抗体产生和终末器官损伤的基因分离来寻找疾病所需的基因修饰因子。在这里，我们关注控制SLE发病的前两个步骤的机制：对自身和外周自身反应性扩增的耐受性丧失。Aim 1的目标是确定我们最近发现的两个新基因座Wam1和Wam2对自身抗体产生的贡献。将产生同源小鼠，以测试这些基因座如何在CD45磷酸酶活性过度活跃的情况下调节耐受阈值。在Aim 2中，我们评估了Wam1中一个有希望的候选基因Toll样受体（TLR） 9在疾病发病机制中的作用。TLR9多态性的分子模型表明，它们映射到DNA配体结合域中富含亮氨酸的重复序列。我们的初步数据表明，B6和BALB/c小鼠对TLR9刺激的反应存在差异。这些差异被CD45E613R突变进一步调节，表明CD45和TLR9信号网络之间存在一种新的相互作用。我们将使用遗传和混合骨髓嵌合体方法来确定TLR9对自身抗体产生的影响，并确定它在CD45E613R小鼠中必须发挥作用的细胞区室。Aim 3的重点是探究TLR9多态性和CD45E613R突变调节耐受性的细胞和分子机制。我们将评估观察到的差异是否由于与配体相互作用的改变，细胞内运输的扰动和/或信号转导网络的改变。这些研究的结果不仅有助于阐明耐受的机制，而且应该为免疫系统的适应性臂和先天臂如何在全身自身免疫中相互作用提供新的见解。在人类自身免疫性疾病的发病机制中，这是一个非常重要的话题，鉴于人们对靶向tlr治疗自身免疫性疾病和作为疫苗策略中的佐剂的兴趣日益浓厚，这一话题具有广泛的影响。