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: 10311019
• 负责人: Annemieke de Jong
• 金额: $ 32.08万
• 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/10311019
• 关键词: Acute; Anti-Inflammatory Agents; Antigen-Presenting Cells; Antigens; Arachidonic Acids; Asthma; Atherosclerosis; Autoantigens; Autoimmune; Biological Assay; Blood; CD1 Antigens; CD1a antigen; Cell Culture Techniques; Cell membrane; Cells; Chronic; Clinical; Clonal Expansion; Clone Cells; Complex; 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; Psoriatic Arthritis; 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; base; 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 CD1蛋白质在结构上与MHC I类相关，但它们不是肽，而是将脂质抗原呈现于T 细胞。我们和其他人表明，识别自脂的CD1限制的T细胞在人中很丰富 T细胞库，但尚不清楚这些T细胞在体内如何调节这些T细胞的激活。公开反应性 自脂表明必须严格调节抗原CD1-脂质复合物，以防止连续 T细胞刺激。脂肪酸和溶物磷脂酰胆碱（LPC）均被确定为某些抗原 人CD1限制的T细胞。当酶磷脂酶A2（PLA2）作用于 膜磷脂，支持PLA2活性在CD1自抗原产生中的作用。自从 分泌的PLA2（SPLA2）因组织损伤和感染而增加，我们假设SPLA2 人类的活性是一种常见的机制，通过该机制调节CD1限制的T细胞的激活， 通过暂时增加CD1自脂抗原的可用性。这是我们的初步支持的 观察到PLA2在抗原呈现细胞上的活性导致CD1依赖性T细胞在健康中的活化 个人。此外，由于SPLA2水平在许多慢性炎症条件下组成型升高，所以 包括类风湿关节炎，哮喘，动脉粥样硬化和牛皮癣，这种机制可能是持续性T的基础 通过持续高水平的自脂抗原在这些条件下的细胞激活。在这个建议中，我们将 系统地研究SPLA2活性与脂质特异性T细胞群体激活之间的联系， 表征人类CD1限制的T细胞种群，这些细胞群体响应PLA2衍生的磷脂分解 产品。使用T细胞培养和人类皮肤外植模，我们将确定PLA2活性是否诱导 溶血磷脂反应性T细胞种群的激活/扩展。我们将调查人类的广度 溶血磷脂特异性的T细胞库及其特异性/滥交。为此，我们使用一个面板 溶血磷脂的CD1四聚体和CD1板测定法。最后，我们将应用组合的单细胞TCR 从健康供体和牛皮癣分离出的CD1-LPC四聚体+ T细胞的测序和功能表型 患者，确定这些人群是否主要具有促炎或免疫调节功能，并且 克隆扩张是否发生在炎症性皮肤病的背景下。该建议将提供见识 在SPLA2活性是否是人类CD1限制的T细胞激活的重要驱动力，并将阐明 响应T细胞种群的特异性和功能。因为SPLA2活性对于两个急性都是核心 和慢性炎症，这项研究的结果将使人们更好地了解常见的生理 在多种不同的炎症条件下可以激活T细胞的途径，并提供新颖 在脂质特异性T细胞激活的模式下的见解。