Myeloid-Derived Regulatory Cells in Asthma

 描述（由申请人提供）：目的：本提案的目的是研究由产生自由基的髓源性调节细胞（MDRC）产生的氧化剂修饰的自身肽可触发气道高反应性（AHR）的新概念。我们最近的特点是MDRC作为关键的调节剂的气道炎症在小鼠和人类。MDRC使用活性氧和活性氮物质（ROS和RNS）来增强T细胞增殖并加剧AHR。我们最近的研究表明，MDRC诱导自身肽的硝化和氧化修饰，这些肽是免疫原性新抗原，尚未建立耐受性。因此，这些新抗原可以引起代表一种新形式的自身免疫的病理性炎症反应。因此，MDRC是耐受性和炎症之间平衡的调节剂。在目的1中，我们将鉴定由哮喘患者中的促炎性气道MDRC产生的修饰的自身抗原/抗原肽。我们将确定与O2的HLA-Class II分子结合的肽库。产生从正常和哮喘受试者中分离的气道MDRC，并定义这些自身肽的ROS和RNS诱导的修饰。这些研究将通过从支气管肺泡灌洗（BAL）MDRC中洗脱II类结合肽，并通过质谱法鉴定这些肽的硝化和氧化修饰来进行。在目标2中，我们将确定在哮喘患者中由产生ROS的MDRC呈递的修饰的自身蛋白是否是真正的新抗原。从健康和哮喘受试者纯化的外周血T细胞和气道MDRC，以及体外修饰的自身蛋白/肽将用于功能测定， 有限稀释分析和共培养以研究T细胞增殖应答、克隆增殖和Th极化。我们将使用小鼠哮喘模型来研究MDRC介导的Th极化的分子机制。这些研究将为MDRCs在哮喘中作为免疫耐受和炎症调节剂的重要作用提供证据，并阐明哮喘的新致病模式。翻译后修饰肽新抗原的鉴定可以帮助定义表征哮喘表型的生物标志物。这些研究也有可能开发新的和改进的治疗策略，以靶向MDRC，用于哮喘表型亚组的疾病控制（即，精确/个性化医疗方法）。我们将获得潜在的新肽免疫治疗策略的洞察力，靶向抗原特异性T细胞与新的合成肽代表修饰的T细胞表位。.

 DESCRIPTION (provided by applicant): Objective: The goal of this proposal is to investigate the novel concept that oxidant-modified self-peptides produced by free radical producing myeloid-derived regulatory cells (MDRCs) can trigger airway hyper- responsiveness (AHR). We recently characterized MDRCs as critical regulators of airway inflammation in both mice and humans. MDRCs use reactive oxygen and reactive nitrogen species (ROS and RNS) to enhance T cell proliferation and exacerbate AHR. Our recent studies show that MDRCs induce nitrative and oxidative modifications of self-peptides which are immunogenic neo-antigens for which tolerance has not been established. Consequently, these neo-antigens can elicit pathologic inflammatory responses that represent a novel form of autoimmunity. MDRCs thus are regulators of balance between tolerance and inflammation. In Aim 1, we will identify modified self-antigens/antigenic peptides produced by pro-inflammatory airway MDRCs in asthmatics. We will determine the peptide repertoire bound to HLA-Class II molecules of O2.-- producing airway MDRCs isolated from normal and asthmatic subjects, and define the ROS- and RNS-induced modifications of these self-peptides. These studies will be conducted by eluting the Class II-bound peptides from bronchoalveolar lavage (BAL) MDRCs, and identifying the nitrative and oxidative modifications of these peptides by mass spectrometry. In Aim 2, we will determine if modified self-proteins presented by ROS- producing MDRCs in asthmatics are true neo-antigens. Peripheral blood T cells and airway MDRCs purified from healthy and asthmatic subjects, and in-vitro modified self-proteins/peptides will be used in functional assays, limiting dilution analyses and co-cultures to investigate T cell proliferative responses, clonal proliferations and Th polarization. We will use a murine model of asthma to examine molecular mechanisms of MDRC-mediated Th polarization. These studies will provide evidence of a major role for MDRCs as regulators of immune tolerance and inflammation in asthma, and elucidate a new pathogenic paradigm for asthma. Identification of post- translational modified peptide neo-antigens can help define biomarkers to characterize asthma phenotypes. These studies also have the potential to enable development of new and improved therapeutic strategies to target MDRCs for disease control of subsets of asthma phenotypes (i.e., a precision/personalized medicine approach). We will obtain insight for potential novel peptide immunotherapy strategies targeting antigen- specific T cells with novel synthetic peptides representing modified T cell epitopes. .