The NOTCH Signaling Pathway in Large Vessel Vasculitis

项目摘要 大血管炎(LVV)，如巨细胞性大动脉炎(GCA)，会导致失明、中风、主动脉弓 综合征、主动脉瘤、高血压和心肌功能不全。在老龄化的人口中， 需要长期治疗的LVV患者一直在稳步上升，而治疗性医疗设备 仍然严格限制在大剂量皮质类固醇的使用。在过去的十年里，在 提示先天免疫系统和获得性免疫系统参与了LVV的免疫发病机制。然而，有一个 我们对这种疾病为什么会以主动脉及其主要分支为靶点，以及免疫系统如何 动脉壁中的间质通讯启动和促进了血管炎。病原性免疫反应 有抗原诱导的克隆性扩张的特征，但我们最近看到了共刺激信号 来自组织壁龛中的常驻细胞的来源在推动组织破坏性免疫方面同样重要。GCA 动脉表达丰富的缺口受体和配体，为Superb 细胞间通讯。阻断Notch信号可有效抑制脉管炎。GCA来源的CD4T细胞 患者结构性地表达NOTCH1受体，使他们能够与Noch配体相互作用，表达 血管平滑肌细胞(VSMC)和内皮细胞(EC)。此应用程序旨在揭示如何 Notch途径参与免疫内皮细胞和免疫间质的通讯，以及Notch如何- 依赖的信号形成血管生成T细胞反应和不适应的VSMC和EC行为。这个 该项目建立在一系列使能资源的基础上；包括GCA患者的临床表型队列； 一种新的人体动脉壁三维模型系统，允许从 可堆叠的单元，填充了定义的细胞种群；以及携带炎症的人源化小鼠模型 人体动脉。通过配体竞争可以阻止对Notch受体和配体的访问 抗体/融合蛋白和细胞可通过RNAi技术使Notch信号缺失。特定的 目的1在机制水平上研究VSMC和EC上的缺口配体如何调节VSMC和EC的效应器功能 血管生成的CD4T细胞；调节其生长、组织侵袭能力和细胞因子的产生。特定的 目标2试图确定可用于抑制NOTCH1表达或靶向的信号网络 致病T细胞中依赖缺口的生存信号。干扰Notch衍生的小分子抑制剂 信号将在嵌合体模型中进行测试，以确定它们的抗血管潜力。具体目标3侧重于 VSMC作为信号发送和接收细胞的作用及其决定配体缺口的方式 相互作用影响VSMC的存活、迁移、基质产生、收缩和ROS释放。具体目标4 揭示了患者来源的CD4+NOTCH1+T细胞通过何种分子机制调节 内皮细胞的功能行为，并研究这种T细胞如何调节内皮细胞的促炎功能， 内皮细胞屏障的血管生成能力、粘附性和泄漏性。

Project Summary Large vessel vasculitides (LVV), such as giant cell arteritis (GCA) cause blindness, stroke, aortic arch syndrome, aortic aneurysm, hypertension and myocardial insufficiency. In an aging population the number of patients requiring chronic management for LVV has been steadily rising, while the therapeutic armamentarium has remained strictly limited to high-dose corticosteroids. The last decade has seen exciting progress in implicating the innate and adaptive immune system in the immunopathogenesis of LVV. However, there is a critical gap in our knowledge why the disease targets the aorta and its major branches and how immuno- stromal communications in the arterial wall initiate and promote vasculitis. The pathogenic immune response has a signature of antigen-induced clonal expansion, but we have recently seen that costimulatory signals deriving from resident cells in the tissue niche are equally important in driving tissue-damaging immunity. GCA arteries express abundant levels of NOTCH receptors and ligands, providing a molecular platform for superb cell-to-cell communication. Blocking of NOTCH signaling effectively inhibits vasculitis. CD4 T cells from GCA patients constitutively express NOTCH1 receptor, enabling them to interact with NOTCH ligand expressing vascular smooth muscle cells (VSMC) and endothelial cells (EC). This application is designed to uncover how the Notch pathway participates in immuno-endothelial and immuno-stromal communications and how NOTCH- dependent signaling shapes vasculitogenic T cell responses and maladaptive VSMC and EC behavior. The project builds on a series of enabling resources; including a clinically phenotyped cohort of GCA patients; a novel 3-D model system of human arterial walls which permits assembly of custom-made vessels from stackable units populated with defined cell populations; and a humanized mouse model carrying inflamed human arteries. Access to Notch receptor and ligands can be blocked through ligand-competing antibodies/fusion proteins and cells can be rendered Notch signaling deficient by RNAi technology. Specific Aim 1 examines on a mechanistic level how NOTCH ligands on VSMC and EC regulate effector functions of vasculitogenic CD4 T cells; modulate their growth, tissue invasion capacity and cytokine production. Specific Aim 2 seeks to identify signaling networks that can be utilized to either suppress NOTCH1 expression or target NOTCH-dependent survival signals in pathogenic T cells. Small molecule inhibitors disrupting Notch-derived signals will be tested in the chimera model for their anti-vasculitic potential. Specific Aim 3 is focused on the role of VSMC as signal-sending and signal-receiving cells and determines how NOTCH-NOTCH ligand interactions affect VSMC survival, migration, matrix production, contractility and ROS release. Specific Aim 4 unravels the molecular mechanisms through which patient-derived CD4+NOTCH1+ T cells regulate the functional behavior of ECs and investigates how such T cells modulate EC proinflammatory functions, angiogenic capacity, adhesiveness and leakiness of the EC barrier.