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，其中自身抗体 （自身抗体）在引发组织破坏中发挥关键作用。已发现多种免疫异常， SLE 患者的 T 细胞和 B 细胞过度活跃，但其发病机制仍然是个谜。这 知识差距是及时诊断、早期治疗干预和治疗的重大障碍。 潜在的预防。我们提出了一种高度创新的致病模型，将典型的不规则现象联系起来 患有 SLE 的患者，包括在临床表现前几年就存在自身抗体 疾病、针对细胞凋亡碎片的大型免疫复合物 (IC) 和自身抗体的存在 循环、产生更高水平的 I 型干扰素 (IFN) 及其靶基因，以及 B 细胞和 T 细胞过度活跃。所提出的假设模型的核心组成部分是 脾脏边缘区 (MZ) 边缘区巨噬细胞 (MZM) 的耐受能力 在 SLE 的进展中发挥着关键作用。我们认为，通常较大的区域正在逐渐受到侵蚀。 SLE 临床前疾病阶段 MZM 的耐受能力储备。当 MZM 的耐受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 型干扰素的事件，这些事件会导致 IFN 进一步快速丧失 耐受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，临床前状态期间 MZM 的耐受能力的侵蚀是 主要由循环凋亡细胞抗原 (AC-Ag) 和增强免疫原性的 IgG IC 驱动 与 I 型 IFN 通路结合的信号会降低 MZM 的耐受能力。 在分子水平上，我们认为 MZM 耐受能力的丧失与 随着 AC-Ag/IC 的响应，MZM 中布鲁顿酪氨酸激酶 (Btk) 的表达增加。作为 Btk 的表达进一步增加，MZM 将从其邻近的解剖位置重新定位 FO 并定位到 MZ 的更偏远地区。有些人开发了增加 I 型 IFN 的 IC MZM 中的信号传导和 Btk 诱导达到促炎性阈值 “触发”加速临床疾病的发生。 目的 1 将确定 Btk 的 autoAb-IC 诱导是否会导致 MZM 功能障碍和丧失。 目标 2 将确定 IFN¿ 和 IC 是否共同作用以打破 MZM 耐受性。 ¿ 目标 3 将确定 pBtk 的升高是否会导致 MZ 巨噬细胞的损失、 SLE 患者炎症巨噬细胞和 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 分析以检测与功能丧失相关的异常信号事件 由于人类和小鼠中 pBtk 异常上调而导致 MZM 数量增加。我们也会申请B 细胞四聚体技术能够追踪致病性多反应性自身抗体形成 B 的发展 与 MZM 数量和耐受功能下降相关的细胞。 Btk活动将被操纵 通过使用不可逆 Btk 抑制剂、PCI-32765 或脂质体基因疗法对小鼠进行全身治疗， 直接将 Btk shRNA 或 PCI-32765 靶向 MZM。 意义：这个假设模型如果被证明是正确的，将准确指出转型中的一个决定性事件 从临床前到临床 SLE，这将表明可用于早期诊断的生物标志物 SLE 的数量，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。这将对早期和未来产生重大影响。 因此，使用当前可用的治疗策略进行更有效的干预。此外，结果将 提供对将 Btk 开发为 SLE 潜在治疗靶点至关重要的见解。