Btk breaks the tolerance of marginal zone macrophages to apoptotic antigens

Btk打破了边缘区巨噬细胞对凋亡抗原的耐受性

• 批准号: 8629254
• 负责人: John D Mountz
• 金额: --
• 依托单位: BIRMINGHAM VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2017-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8629254
• 关键词: Activities of Daily Living; Agammaglobulinaemia tyrosine kinase; Anatomy; Antigen-Antibody Complex; Antigens; Apoptotic; Area; Arts; Autoantibodies; Autoimmune Diseases; Autoimmune Process; Autoimmunity; B-Lymphocytes; Biochemical; Biological Markers; Biology; Blood Circulation; Cells; Clinical; Data; Defect; Detection; Development; Dimensions; Dioxygenases; Disease; Early Diagnosis; Ensure; Event; Experimental Models; Flow Cytometry; Functional disorder; Gene Targeting; Genes; Human; Human Characteristics; Hyperactive behavior; Image; Immune; Immune System Diseases; Immunoglobulin G; Individual; Inflammatory; Interferon Type I; Interferons; Interleukin-10; Interleukin-6; Knowledge; Lead; Link; Liposomes; Lupus; Mediating; Modeling; Molecular; Mus; Onset of illness; Pathogenesis; Pathway interactions; Patients; Pharmaceutical Preparations; Phase; Phenotype; Play; Positioning Attribute; Prevention; Process; Production; Recruitment Activity; Research; Resources; Role; Signal Transduction; Spleen; Staging; Structure; Systemic Lupus Erythematosus; T-Lymphocyte; Techniques; Technology; Testing; Therapeutic; Therapeutic Intervention; Time; Tissues; Tyrosine Kinase Inhibitor; Work; base; effective intervention; gene therapy; immunogenic; in vivo; indoleamine; innovation; insight; loss of function; macrophage; mouse model; nanoscience; novel; novel therapeutic intervention; pre-clinical; prevent; public health relevance; response; small hairpin RNA; success; therapeutic target; vector

Systemic lupus erythematosus (SLE) is a multifactorial autoimmune disease in which autoantibodies (autoAbs) play a key role in eliciting tissue destruction. Multiple immune irregularities have been identified, including hyperactivity of T and B cells, in patients with SLE but its pathogenesis remains an enigma. This gap in knowledge is a significant impediment to timely diagnosis, early therapeutic intervention and potential prevention. We propose a highly innovative pathogenic model that links irregularities typical of patients with SLE including the presence of autoAbs several years prior to manifestation of clinical disease, the presence of large immune complexes (ICs) and autoAbs targeting apoptotic debris in the circulation, the production of higher levels of type I interferons (IFNs) and their target genes, and the hyperactivity of B and T cells. The central component of the proposed hypothetical model is that the tolerogenic capacity of marginal zone macrophages (MZMs) in the marginal zone (MZ) of the spleen plays a pivotal role in the progression of SLE. We propose that there is a gradual erosion of the normally large reserve in the tolerogenic capacity of the MZMs during the pre-clinical disease phase of SLE. When the tolerogenic capacity of the MZMs declines below a critical threshold, the individual becomes susceptible to inciting events, especially those that induce type I IFNs, that precipitate a further rapid loss of tolerogenic capacity resulting in production of high titers of pathogenic autoAbs and clinical disease. We further propose that the erosion of the tolerogenic capacity of the MZMs during the pre-clinical state is driven primarily by circulating apoptotic cell antigens (AC-Ags) and IgG ICs that enhance immunogenic signals which in combination with type I IFN pathways reduce the tolerogenic capacity of MZMs. At the molecular level, we propose that the loss of the tolerogenic capacity of the MZMs is associated with an increase in expression of Bruton tyrosine kinase (Btk) in MZMs in response to AC-Ag/ICs. As the expression of Btk is further increased, the MZMs will relocate from their anatomic position adjacent to the FO and locate to more remote areas of the MZ. Some individuals develop ICs that increase type I IFN signaling and Btk induction in MZMs to the point that a threshold is reached at which a pro-inflammatory "trigger" precipitates the onset of clinical disease. ¿ Aim 1 will determine if autoAb-ICs induction of Btk leads to MZM dysfunction and loss. ¿ Aim 2 will determine if IFN¿ and ICs work together to break MZM tolerance. ¿ Aim 3 will determine if elevation of pBtk leads to loss of MZ macrophages, development of inflammatory macrophages and elevation of type I IFN genes in SLE patients. The proposed work will use state-of-art confocal imaging and high dimension phospho-flow cytometry analyses to enable detection of the aberrant signaling events associated with loss of function and numbers of MZMs due to abnormally upregulated pBtk in both humans and mice. We will also apply B cell tetramer technology to enable tracking the development of pathogenic multireactive autoAb forming B cells associated with the decline of MZM numbers and tolerance function. Btk activity will be manipulated by systemic treatment of mice with an irreversible Btk inhibitor, PCI-32765 or liposome gene therapy to directly target Btk shRNA or PCI-32765 to MZMs. Significance: This hypothetical model, if proven true, would pinpoint a defining event in the transition from pre-clinical to clinical SLE, which would suggest a biomarker that could be used in earlier diagnosis of SLE, i.e., the numbers and Btk phenotype of the MZMs in experimental models of autoimmunity, and the Btk phenotype of PBMCs from patients. This would have major implications in terms of earlier and thus more effective intervention using currently available therapeutic strategies. In addition, the results will provide insights critical to the development of Btk as a potential therapeutic target in SLE.

系统性红斑狼疮（SLE）是一种多因素自身免疫性疾病， （autoAb）在引发组织破坏中起关键作用。已经发现了多种免疫异常， 包括T和B细胞的过度活跃，但其发病机制仍然是一个谜。这 知识的差距是及时诊断、早期治疗干预和 潜在预防。我们提出了一个高度创新的致病模型，将典型的 SLE患者，包括在临床表现前几年存在自身抗体 疾病，大的免疫复合物（IC）和autoAb靶向凋亡碎片的存在， 循环，产生更高水平的I型干扰素（IFN）及其靶基因， B和T细胞过度活跃。拟议的假设模型的核心组成部分是， 脾脏边缘区（MZ）中边缘区巨噬细胞（MZMs）的致耐受能力发挥着重要作用。 在SLE的进展中起关键作用。我们认为，正常情况下， 在SLE的临床前疾病阶段保留MZM的致耐受能力。当 MZM的致耐受性能力下降到临界阈值以下，个体变得易感 刺激事件，特别是那些诱导I型IFN的事件，这些事件促使进一步快速丧失IFN-γ。 致耐受性能力导致产生高滴度的致病性自身抗体和临床疾病。我们 进一步提出，在临床前状态期间MZM的致耐受性能力的侵蚀是 主要由循环凋亡细胞抗原（AC-Ag）和IgG IC驱动， 与I型IFN途径组合的信号降低MZM的致耐受性能力。 在分子水平上，我们认为MZM致耐受能力的丧失与 在MZM中布鲁顿酪氨酸激酶（Btk）的表达增加以响应AC-Ag/IC。为 当Btk的表达进一步增加时，MZM将从其邻近于MZM的解剖位置重新定位。 FO和定位到MZ的更偏远的地区。有些人开发的IC增加I型IFN MZM中的Btk诱导达到促炎性细胞因子释放的阈值。 “触发”促使临床疾病的发作。 目标1将确定autoAb-IC诱导Btk是否导致MZM功能障碍和损失。 目标2将确定IFN和IC是否共同工作以打破MZM公差。 目标3将确定pBtk的升高是否导致MZ巨噬细胞的损失， SLE患者中炎性巨噬细胞和I型IFN基因升高。 拟议的工作将使用最先进的共聚焦成像和高维磷酸流式细胞术 分析以能够检测与功能丧失相关的异常信号传导事件， 由于人类和小鼠中pBtk的异常上调，MZM的数量增加。我们还将应用B 细胞四聚体技术能够跟踪致病性多反应性自身抗体形成B的发展 与MZM数量下降和耐受功能相关的细胞。Btk活动将被操纵 通过用不可逆的Btk抑制剂、PCI-32765或脂质体基因疗法全身治疗小鼠， 直接将Btk shRNA或PCI-32765靶向MZM。 意义：如果这个假设模型被证明是正确的，它将指出转型中的一个决定性事件 从临床前到临床SLE，这将提示可用于早期诊断的生物标志物 SLE，即，自身免疫实验模型中MZM的数量和Btk表型，以及 患者PBMC的Btk表型。这将对更早和更长时间的工作产生重大影响。 从而使用当前可用的治疗策略进行更有效的干预。此外，结果将 为Btk作为SLE潜在治疗靶点的发展提供了重要见解。