Defining how Microbes Drive Abnormal T Cell Responses in Rheumatoid Arthritis

定义微生物如何驱动类风湿性关节炎中的异常 T 细胞反应

• 批准号: 10314018
• 负责人: Laura Su
• 金额: --
• 依托单位: PHILADELPHIA VA MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10314018
• 关键词: Adult; Age; Aging; Antigens; Arthritis; Autoantigens; Autoimmune Process; Autoimmunity; Automobile Driving; Avidity; Binding; Biological Assay; Biological Markers; Biology; CD4 Positive T Lymphocytes; Cell Aging; Cell physiology; Cells; Chronic; Chronic Disease; Clinical; Communities; Competence; Complex; Cytometry; Cytoplasmic Granules; Data; Development; Disease; Environment; Etiology; Functional disorder; Future; Granzyme; Healthcare; Heterogeneity; Immune; Immune system; In Vitro; Individual; Inflammation; Inflammation Mediators; Inflammatory; Interferon Type II; Lead; Libraries; Link; Measures; Mediating; Memory; Microbe; Monitor; Pathogenesis; Patient Care; Patients; Peptide/MHC Complex; Peptides; Physiological; Play; Population; Premature aging syndrome; Process; Proteins; Publishing; Research; Rheumatoid Arthritis; Sampling; Signal Transduction; System; T cell response; T memory cell; T-Lymphocyte; T-Lymphocyte Subsets; TNF gene; Telomere Shortening; Testing; Time; United States; United States Department of Veterans Affairs; Veterans; Viral Antigens; Virus; Yeasts; combat; cross reactivity; cytokine; cytomegalovirus matrix protein 65kDa; design; disease diagnosis; interest; joint destruction; memory CD4 T lymphocyte; microbial; novel; novel marker; novel strategies; perforin; premature; public health relevance; response; senescence; tool

 DESCRIPTION (provided by applicant): Rheumatoid arthritis (RA) is a debilitating disease that causes inflammation and deforming joint destruction. RA afflicts 1.5 million people in the United States and is becoming increasingly more prevalent in the veteran community as this population ages. It is also one of the most expensive illnesses to treat, resulting in hundreds of millions of dollars in increased health care spending by the Veteran Administration (VA). T cell dysfunction plays a key role in driving RA pathogenesis. Past studies have identified premature aging of CD4+ T cells in RA patients. Despite being called "senescent", these cells are highly pro-inflammatory and produce high levels of TNFα, IFNγ, and cytolytic granules. There are still many unanswered questions about senescent CD4+ T cells. In particular, the mechanisms that accelerate T cell senescence and the effector functions that contribute to autoimmunity remain poorly defined. Understanding the etiology and the impact of premature T cell senescence in RA may lead to new approaches to monitor and treat this currently incurable chronic disease. In recently published data, we identified an abundance of memory CD4+ T cells specific for viral antigens in adults who have never been infected with these viruses. Intriguingly, these T cells can be activated in vitro by similar peptides from common microbes, indicating that a subset of CD4+ memory cells is generated predominately by cross-reactive microbial and/or environmental antigen stimulation. In new preliminary studies, we found that many memory T cells generated by cross-reactive stimulation are Ki67 positive, suggesting that these cells receive continuous stimulatory signals. Because continuous or repetitive TCR stimulation has the potential to drive senescence, we hypothesize that chronic stimulation by common environmental antigens contributes to the development of senescent CD4+ T cells. In new preliminary studies, we have begun to investigate the biology of senescence in RA patients. We identified several distinct CD4+ T cell subsets, including a CD5 high population that produces the greatest level of perforin. High CD5 expression suggests a stronger avidity for self-antigens. We thus hypothesize that senescent CD4+ T cells are heterogeneous and contain subsets that are self-reactive and their cytolytic activity contributes to RA pathogenesis. The proposed study has two interrelated yet independent objectives. The first is to define the functional heterogeneity of senescent CD4+ T cells in RA patients and test the hypothesis that the most cytolytic senescent subsets are preferentially expanded in patients with active disease. We will investigate the full diversity of senescent T cells in RA patients using cytometry by time-of-flight (CyTOF). CyTOF measures the expression of more than 40 proteins at a single cell level, and thus it is an ideal tool for discovering new cellular function. The second objective is to determine whether senescent T cells from RA patients are more cross-reactive than nonsenescent T cells from the same individual and if these cells have the ability to recognize self-antigens relevant in RA. The breadth of cross-reactivity will be determined in a systematic approach using a yeast library that displays over 108 random peptide-MHC complexes. Whether senescent T cells can recognize self-peptides from putative RA autoantigens will be determined by direct binding to peptide- MHC complexes using tetramers and by assaying functional response to antigen stimulation. Data generated from this study will provide the fundamental information necessary to develop new disease biomarkers and for designing tolerizing approaches to combat premature senescence in RA patients.

 描述（由申请人提供）： 风湿性关节炎（RA）是一种使人衰弱的疾病，可导致炎症和变形关节破坏。RA在美国困扰着150万人，随着这一人群的老龄化，RA在退伍军人社区中变得越来越普遍。它也是治疗费用最高的疾病之一，导致数亿美元的医疗保健费用增加 退伍军人管理局（Veteran Administration）。T细胞功能障碍在驱动RA发病机制中起关键作用。过去的研究已经确定了RA患者中CD 4 + T细胞的过早老化。尽管被称为“衰老”，但这些细胞具有高度促炎性，并产生高水平的TNFα、IFNγ和溶细胞颗粒。关于衰老的CD 4 + T细胞仍有许多未解之谜。特别是，加速T细胞衰老的机制和有助于自身免疫的效应器功能仍然不清楚。了解RA中T细胞过早衰老的病因和影响可能会导致新的方法来监测和治疗这种目前无法治愈的慢性疾病。在最近发表的数据中，我们在从未感染过这些病毒的成年人中发现了大量对病毒抗原具有特异性的记忆性CD 4 + T细胞。有趣的是，这些T细胞可以在体外被来自普通微生物的类似肽激活，表明CD 4+记忆细胞的子集主要由交叉反应性微生物和/或环境抗原刺激产生。在新的初步研究中，我们发现许多由交叉反应刺激产生的记忆T细胞是Ki 67阳性的，这表明这些细胞接受连续的刺激信号。由于连续或重复的TCR刺激有可能驱动衰老，我们假设常见环境抗原的慢性刺激有助于衰老的CD 4 + T细胞的发育。在新的初步研究中，我们已经开始调查RA患者衰老的生物学。我们鉴定了几种不同的CD 4 + T细胞亚群，包括产生最高水平穿孔素的CD 5高群体。高的CD 5表达表明对自身抗原有更强的亲合力。因此，我们假设，衰老的CD 4 + T细胞是异质性的，并含有亚群，是自我反应和它们的细胞溶解活性有助于RA的发病机制。拟议的研究有两个相互关联但又独立的目标。第一个是定义RA患者衰老的CD 4 + T细胞的功能异质性，并检验最溶细胞的衰老亚群在活动性疾病患者中优先扩增的假设。我们将使用飞行时间流式细胞术（CyTOF）研究RA患者衰老T细胞的全部多样性。CyTOF在单细胞水平上测量40多种蛋白质的表达，因此它是发现新细胞功能的理想工具。第二个目标是确定RA患者的衰老T细胞是否比同一个体的非衰老T细胞更具交叉反应性，以及这些细胞是否具有识别RA相关自身抗原的能力。交叉反应性的宽度将使用展示超过108个随机肽-MHC复合物的酵母文库以系统方法确定。衰老T细胞是否可以识别来自推定RA自身抗原的自身肽将通过使用四聚体直接结合肽- MHC复合物和通过测定对抗原刺激的功能应答来确定。从这项研究中产生的数据将提供必要的基本信息，以开发新的疾病生物标志物和设计耐受性的方法，以打击RA患者的早衰。