Role of human innate immune mutations in loss of tolerance to Borrelia burgdorferi

人类先天免疫突变在伯氏疏螺旋体耐受性丧失中的作用

基本信息

批准号：
10461854
负责人：
Linden T Hu
金额：
$ 58.86万
依托单位：
TUFTS UNIVERSITY BOSTON
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-09-08 至 2025-08-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10461854
关键词：
Affect Amino Acids Animals Antibiotic Therapy Arthritis Bacteria Belief Biological Assay Borrelia burgdorferi Carditis Cell Death Cell Line Cell surface Cells Clinical Collaborations Confocal Microscopy Dangerousness Data Defect Development Disease Exanthema Exhibits Exposure to Failure Fatigue Genes Health Heterodimerization Hour Human Human Genetics Human Inbreeding Immune Immune Tolerance Immune response Immune system Immunologic Receptors In Vitro Inbred Mouse Infection Inflammation Inflammatory Inflammatory Response Innate Immune System Isoleucine Knock-out Laboratories Life Ligands Link Lipoproteins Location Lyme Arthritis Lyme Disease Measures Mediating Meningitis Metabolism Modeling Movement Mutation Natural Immunity Neurocognitive Organism Pain Pathway interactions Patients Process Reaction Reporting Research Personnel Risk Role Serine Signal Pathway Signal Transduction Signaling Molecule Single Nucleotide Polymorphism Site Stimulus Symptoms Syndrome TLR1 gene TLR2 gene Testing Time Ursidae Family Vector-transmitted infectious disease acute infection cell type cytokine experimental study flu glucose metabolism immune clearance in vivo individual patient macrophage mouse model mutant pathogen persistent symptom polarized cell receptor receptor expression response trafficking weapons

项目摘要

The majority of symptoms of Lyme disease are due to the host immune response to the organism, Borrelia burgdorferi, and resolve over time, even without antibiotic treatment. In its natural host, little or no reaction to infection can be seen despite the fact that the organism persists for life. In humans and inbred mice (which do develop immune responses to the organism), inflammation is thought to be initiated by receptors of the innate immune system. In vitro, loss of innate, pathogen-sensing receptors that recognize B. burgdorferi such as toll- like receptor 2 (TLR2) results in a decrease inflammatory response. However, in vivo studies of animals deficient in these receptors or their adaptor molecules do not show reduced inflammation and in many cases show increased inflammation. Recently, in humans, a single nucleotide polymorphism (SNP) in the tlr1 gene that results in loss of expression of the receptor on the cell surface was found to be associated with increased inflammation and symptoms. This suggests that after the initial stimulus, a major role for these innate immune molecules is in dampening inflammation. One major difference between in vitro studies and the in vivo infections is that the in vitro experiments are typically conducted by measuring responses minutes to hours after exposure to the organism. We have evidence that more prolonged exposures in vitro result in the development of innate immune “tolerance” to stimulation by B. burgdorferi. In this proposal, we will study the role of the tlr1-1805GG SNP in disrupting innate immune tolerance, thereby leading to excessive inflammatory responses. The 1805GG SNP results in a loss of localization to the cell surface but does not affect the activity of the receptor. Therefore, in Aim 1, we will first determine the effects of the SNP on specific, localization-dependent signaling pathways and downstream cytokine responses. We have previously shown that the TLR1/TLR2 ligand Pam3CSK4 can initiate signaling from both intracellular and cell surface locations although the signals are different in each location. It is likely that the tlr1- 1805GG SNP continues to signal endosomally. We will track movements of the receptors and ligands as well as compare a tlr1 deletion to the tlr1-1805GG SNP. In Aim 2, we will assess the role of the tlr1-1805GG SNP on macrophage reprogramming leading to loss of innate immune tolerance to B. burgdorferi. We will focus on understanding its effects on macrophage polarization, cell death and the role of glucose metabolism. Finally, in Aim 3, using isogenic B. burgdorferi isolates that do or do not initiate tolerance, we will identify the role of specific components of the organism in moderating macrophage reprograming and loss of tolerance. We believe that B. burgdorferi infection, where there is prolonged infection with minimal evidence of inflammation over time, is an excellent model to understand how the immune system can control responses to invasive bacteria that pose less threat to health than continued efforts to clear the infection—in essence making the organism an invasive “commensal” through the development of innate immune tolerance.

莱姆病的大多数症状是由于宿主对生物体的免疫反应引起的即使没有抗生素治疗，也可以随着时间的流逝而解决。在天然主机中，很少或没有反应尽管有机体持续存在生命，但仍可以看到感染。在人类和近交小鼠中对组织产生免疫反应），炎症被认为是由先天的接收者发起的免疫系统。在体外，识别B. burgdorferi（例如Toll-）的先天病原体传感器的丧失 - 像受体2（TLR2）一样，炎症反应降低。但是，动物体内研究这些受体或其衔接子分子缺陷并未显示出降低的注射，在许多情况下显示炎症增加。最近，在人类中，TLR1基因中的单个核苷酸多态性（SNP）发现发现受体在细胞表面的表达丧失与增加有关炎症和符号。这表明在初始刺激之后，这些先天免疫的主要作用分子正在破坏炎症。体外研究和体内的主要区别感染是在体外实验通常是通过测量响应数分钟到小时来进行的暴露于生物体后。我们有证据表明，在体外延长暴露会导致 B. burgdorferi对刺激的先天免疫“耐受性”的发展。在此提案中，我们将研究TLR1-1805GG SNP在破坏先天免疫耐受性的作用，从而导致过度炎症反应。 1805GG SNP导致本地化损失细胞表面，但不影响接收器的活性。因此，在AIM 1中，我们将首先确定 SNP对特定定位依赖性信号通路和下游细胞因子的影响回答。我们先前已经表明，TLR1/TLR2配体PAM3CSK4可以启动两者的信号传导细胞内和细胞表面位置，尽管每个位置的信号都不同。 TLR1-可能 1805GG SNP继续以内体信号。我们还将跟踪接收器和配体的运动将TLR1删除与TLR1-1805GG SNP进行比较。在AIM 2中，我们将评估TLR1-1805GG SNP的作用关于巨噬细胞的重编程，导致对B. burgdorferi的先天免疫耐受性丧失。我们将重点关注了解其对巨噬细胞极化，细胞死亡和葡萄糖代谢作用的影响。最后，在 AIM 3，使用Isenic B. burgdorferi隔离株（或不启动公差），我们将确定生物体的特定成分调节巨噬细胞重编程和耐受性丧失。我们认为，伯格多菲利（B. burgdorferi 随着时间的流逝，炎症是了解免疫系统如何控制对的反应的绝佳模型侵入性细菌对健康构成的威胁少于继续努力清除感染的努力 - 本质上通过发展先天免疫耐受性，使生物体成为侵入性的“共生”。