Role of secreted phospholipase A2 in the activation of human CD1-restricted T cells

分泌型磷脂酶 A2 在人 CD1 限制性 T 细胞激活中的作用

• 批准号: 10529317
• 负责人: Annemieke de Jong
• 金额: $ 35.64万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10529317
• 关键词: Acute; Anti-Inflammatory Agents; Antigen Presentation; Antigen-Presenting Cells; Antigens; Arachidonic Acids; Arthritis; Asthma; Atherosclerosis; Autoantigens; Autoimmune; Binding; Biological Assay; Blood; CD1 Antigens; CD1a antigen; Cell Culture Techniques; Cell Separation; Cell membrane; Cells; Chronic; Clinical; Clonal Expansion; Complex; Cross Reactions; Eicosanoid Production; Eicosanoids; Enzymes; Fatty Acids; Flow Cytometry; Generations; Homeostasis; Homing; Human; Hydrophobicity; Immune; Immune system; Individual; Infection; Inflammation; Inflammatory; Investigation; Lecithin; Link; Lipids; Lysophosphatidylcholines; Lysophospholipids; MHC Class I Genes; MHC antigen; Membrane; Modeling; Pathogenesis; Pathway interactions; Patients; Peptides; Phenotype; Phospholipase A2; Phospholipids; Physiological; Population; Proteins; Psoriasis; Regulation; Regulatory T-Lymphocyte; Rheumatoid Arthritis; Role; Skin; Specificity; System; T cell receptor repertoire sequencing; T cell response; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte Subsets; Therapeutic; Tissues; antigen binding; autoreactive T cell; blood fractionation; immunoregulation; in vivo; insight; lipid mediator; novel; phospholipase A2 inhibitor; prevent; response; sensor; skin disorder; therapy development; tool

PROJECT SUMMARY CD1 proteins are structurally related to MHC class I, but instead of peptides, they present lipid antigens to T cells. We and others have shown that CD1-restricted T cells recognizing self-lipids are abundant in the human T cell repertoire, yet it remains unclear how the activation of these T cells is regulated in vivo. Overt reactivity to self-lipids suggests that antigenic CD1-lipid complexes must be tightly regulated in order to prevent continuous T cell stimulation. Both fatty acids and lysophosphatidylcholine (LPC) have been identified as antigens for certain human CD1-restricted T cells. These lipids are released when the enzyme phospholipase A2 (PLA2) acts on membrane phospholipids, supporting a role for PLA2 activity in the generation of CD1 self antigens. Since secreted PLA2 (sPLA2) is increased in response to tissue damage and infections, we hypothesize that sPLA2 activity in humans is a common mechanism through which the activation of CD1-restricted T cells is regulated, by temporarily increasing the availability of CD1 self-lipid antigens. This is supported by our preliminary observations that PLA2 activity on antigen presenting cells results in CD1-dependent T cell activation in healthy individuals. Furthermore, since sPLA2 levels are constitutively elevated in many chronic inflammatory conditions, including rheumatoid arthritis, asthma, atherosclerosis and psoriasis, this mechanism may underlie persistent T cell activation in these conditions through continued high levels of self lipid antigens. In this proposal we will systematically investigate the link between sPLA2 activity and activation of lipid-specific T cell populations, and characterize the human CD1-restricted T cell populations that respond to PLA2-derived phospholipid breakdown products. Using T cell cultures and a human skin explant model, we will determine if PLA2 activity induces the activation/expansion of lysophospholipid-reactive T cell populations. We will investigate the breadth of the human lysophospholipid-specific T cell repertoire, and its specificity/promiscuity. For this we use a panel of lysophospholipid-loaded CD1 tetramers, and a CD1 plate assay. Last, we will apply combined single cell TCR sequencing and functional phenotyping to CD1-LPC tetramer+ T cells isolated from healthy donors and psoriasis patients, to determine if these populations primarily have pro-inflammatory or immunoregulatory functions, and whether clonal expansions occur in the context of inflammatory skin disease. This proposal will provide insight in whether sPLA2 activity is a significant driver of human CD1-restricted T cell activation, and will elucidate the specificities and functions of the responding T cell populations. Because sPLA2 activity is central to both acute and chronic inflammation, results from this study will lead to a better understanding of a common physiological pathway through which T cells can be activated in multiple distinct inflammatory conditions, and provide novel insights in modes through which lipid-specific T cell activation may be regulated therapeutically.

项目摘要 CD 1蛋白在结构上与MHC I类相关，但它们不是肽，而是向T细胞呈递脂质抗原。 细胞我们和其他人已经表明，识别自身脂质的CD 1限制性T细胞在人类中是丰富的。 T细胞库，但仍不清楚这些T细胞的激活是如何在体内调节的。明显反应性 自身脂质表明，抗原性CD 1-脂质复合物必须受到严格的调控，以防止连续的 T细胞刺激。脂肪酸和溶血磷脂酰胆碱（LPC）已被确定为某些抗原， 人CD 1限制性T细胞。当磷脂酶A2（PLA 2）作用于 膜磷脂，支持PLA 2活性在CD 1自身抗原产生中的作用。以来 分泌型PLA 2（sPLA 2）在组织损伤和感染时增加，我们假设sPLA 2 在人体中的活性是调节CD 1限制性T细胞活化的常见机制， 通过暂时增加CD 1自身脂质抗原的可用性。这一点得到了我们初步的支持。 观察到抗原呈递细胞上的PLA 2活性导致健康人中CD 1依赖性T细胞活化， 个体此外，由于sPLA 2水平在许多慢性炎症性疾病中组成性升高， 包括类风湿性关节炎、哮喘、动脉粥样硬化和银屑病，这种机制可能是持续T 在这些条件下通过持续高水平的自身脂质抗原的细胞活化。在本提案中，我们将 系统地研究sPLA 2活性与脂质特异性T细胞群活化之间的联系， 表征对PLA 2衍生的磷脂分解应答的人CD 1限制性T细胞群 产品.使用T细胞培养物和人皮肤外植体模型，我们将确定PLA 2活性是否诱导了T细胞增殖。 溶血磷脂反应性T细胞群的活化/扩增。我们将调查人类的广度 溶血磷脂特异性T细胞库及其特异性/混杂性。为此，我们使用一个面板， 溶血磷脂负载的CD 1四聚体和CD 1平板测定。最后，我们将应用组合的单细胞TCR 从健康供体和银屑病中分离的CD 1-LPC四聚体+ T细胞的测序和功能表型分析 患者，以确定这些人群是否主要具有促炎或免疫调节功能，以及 克隆扩增是否发生在炎症性皮肤病的背景下。这一建议将提供洞察力 sPLA 2活性是否是人CD 1限制性T细胞活化的重要驱动因素，并将阐明 特异性和功能的反应T细胞群体。由于sPLA 2活性是急性和慢性炎症的中心， 和慢性炎症，这项研究的结果将导致更好地了解一个共同的生理 T细胞可以通过其在多种不同的炎性病症中活化的途径，并提供新的 在脂质特异性T细胞活化的模式中的见解可以在治疗上进行调节。