Endogenous glycosphingolipid antigens for NKT cells

NKT 细胞的内源性鞘糖脂抗原

• 批准号: 7867908
• 负责人: Dapeng Zhou
• 金额: $ 38.12万
• 依托单位: UNIVERSITY OF TX MD ANDERSON CAN CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-15 至 2014-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7867908
• 关键词: Address; Adoptive Transfer; Agonist; Anabolism; Antigen-Antibody Complex; Antigen-Presenting Cells; Antigens; Area; Asthma; Autoimmune Diseases; Autoimmunity; Bacterial Proteins; Biochemical; Biological Assay; Biology; CD1d antigen; Cell Line; Cells; Cellular Membrane; Ceramide glucosyltransferase; Characteristics; Clinical; Coenzymes; Communicable Diseases; Complex; Defect; Deficiency Diseases; Development; Disease; Enzymes; Event; Evolution; Fractionation; Generations; Genes; Genetic; Genomics; Glycolipids; Glycoside Hydrolases; Glycosphingolipids; Goals; Host Defense; Human; Human Genome; Human Genome Project; Hybrid Cells; Hybrids; Hypersensitivity; Immune; Immune System Diseases; Immune response; Immune system; Immunologic Receptors; Immunomodulators; Infection; Information Storage; Ions; Jaw; Knockout Mice; Knowledge; Leukocyte Adhesion Deficiency; Ligands; Link; Lipid Synthesis Pathway; Lipids; Lymphocyte; MHC antigen; Malignant Neoplasms; Mass Fragmentography; Mass Spectrum Analysis; Memory; Metabolism; Molecular; Molecular Chaperones; Molecular Cloning; Mouse Strains; Mus; Natural Immunity; Natural Killer Cells; Outcome; Pathology; Pathway interactions; Pattern; Pharmaceutical Preparations; Physiological; Play; Proteins; Proteomics; RNA Interference; Receptor Signaling; Regulation; Research; Research Personnel; Research Training; Role; Series; Side; Source; Sphingolipid Activator Proteins; Staging; Stimulus; Structure; Surveys; System; T-Cell Receptor; T-Lymphocyte; T-Lymphocyte Subsets; T-Lymphocyte and Natural Killer Cell; Technology; Testing; Thymus Gland; Tissues; Toll-like receptors; Tumor Antigens; UDP-galactose beta-D-galactosyl-1,4-glycosylceramide alpha-1,3-galactosyltransferase; Vertebrates; adaptive immunity; base; cell killing; cell type; chemical synthesis; embryonic antigen; experience; fight against; insight; isoglobotriaosylceramide; killer T cell; lipid metabolism; macrophage; mast cell; microbial; neutrophil; new technology; novel strategies; novel therapeutic intervention; novel therapeutics; pathogen; prevent; progenitor; public health relevance; receptor; success; vaccine development; viral DNA; viral RNA

DESCRIPTION (provided by applicant): Natural Killer T cells (NKT) are a hybrid cell type of NK cells and T cells, but are activated only by antigenic stimulation. NKT cells bridge innate and adaptive immunity through recognition of lipid ligands from both microbial and self origins. Endogenous NKT ligands, which are metabolism products of self lipids, are involved in immuno-pathology of infectious diseases, auto-immune diseases and cancer. However, molecular identification of these endogenous ligands has been difficult due to technical barriers. Recently, we found that NB-DGJ, a drug which inhibits glucosylceramide synthase, completely abolishes the development of NKT cells. More importantly, we identified isoglobotrihexosylceramide, one of the target glycosphingolipids being inhibited by NB-DGJ, as the first known natural ligand for NKT cells. However, iGb3 synthase knockout mice showed no defect in NKT cell development and function, indicating that other GSL and/or non-GSL ligands exist. Continued development of glycolipidomics assays, assisted by ion trap mass spectrometry technology, enhances our ability to further understand these mechanisms and identify new ligands. In this project, we will test the hypothesis that at least one endogenous ligand of NKT cells, other than iGb3, exists and is responsible for the development and activation of NKT cells. Identifying one or more endogenous ligands may permit new approaches to regulating the function of NKT cells in disease settings such as cancer and autoimmune diseases. The specific aims of this project are: 1) Determine the identities of stimulatory GSL and/or non-GSL antigens by biochemical fractionation and analysis; 2) Utilize the genetic pathways to identify potential endogenous NKT ligands. The molecular identification of natural ligands for NKT cells is not only an urgent, but also a challenging task in the field of innate immunity. Although the search for these ligands has lasted more than a decade, they remain elusive. We therefore have chosen a combined approach of biochemical fractionation/characterization and genetic knockdown of key enzymes to help bring this search to fruition. The completion of human genome project and the advancement of mass spectrometry technology provide the framework to move the field of lipid antigens forward and potentially permit the identification of new therapeutic approaches to some of the most complex immune-related diseases. More important, this project will provide early insights into cellular lipidomics studies, with a specific focus on the important immunological functions of glycolipids. More than 10% of the genes in the human genome are used for lipid metabolism; thus, knowledge and experience gained in this project may have profound implications on studies of functional lipidomics, an important but little-understood area compared with proteomics and genomics. PUBLIC HEALTH RELEVANCE: NKT lymphocytes represent an essential component of innate immunity, that can jump start the adaptive immune responses and regulate the immune outcome. Understanding the identities of the natural ligands for NKT cells is a prerequisite to study the regulation of NKT cells in patho-physiological conditions. Our long-term goal is to elucidate the molecular mechanisms of the biosynthesis pathways of natural ligands for NKT cells, and to identify druggable targets of regulation. The important clinical benefit of this project is 1) novel therapeutic application of lipid-metabolism-interfering drugs in immuno-regulation of NKT cells; 2) identification of new natural NKT ligands as targets for immuno-therapy of autoimmune diseases and cancer.

描述（由申请人提供）：自然杀伤T细胞（NKT）是NK细胞和T细胞的混合细胞类型，但只能通过抗原刺激激活。NKT细胞通过识别来自微生物和自身来源的脂质配体架起先天免疫和适应性免疫的桥梁。内源性NKT配体是自身脂质的代谢产物，参与感染性疾病、自身免疫性疾病和癌症的免疫病理。然而，由于技术障碍，这些内源性配体的分子鉴定一直很困难。最近，我们发现抑制糖基神经酰胺合成酶的药物NB-DGJ可以完全消除NKT细胞的发育。更重要的是，我们确定了异血红蛋白三己糖神经酰胺，这是NB-DGJ抑制的靶鞘糖脂之一，是已知的第一个NKT细胞的天然配体。然而，iGb3合酶敲除小鼠未发现NKT细胞发育和功能缺陷，表明存在其他GSL和/或非GSL配体。在离子阱质谱技术的辅助下，糖脂组学分析的持续发展增强了我们进一步了解这些机制和识别新配体的能力。在这个项目中，我们将验证一个假设，即除了iGb3之外，至少存在一种NKT细胞的内源性配体，并负责NKT细胞的发育和激活。鉴定一种或多种内源性配体可能为调节NKT细胞在癌症和自身免疫性疾病等疾病中的功能提供新的途径。该项目的具体目的是：1)通过生化分离和分析确定刺激性GSL和/或非GSL抗原的身份；2)利用遗传途径鉴定潜在的内源性NKT配体。在先天免疫领域，NKT细胞天然配体的分子鉴定不仅是一项紧迫的任务，也是一项具有挑战性的任务。尽管对这些配体的研究已经持续了十多年，但它们仍然难以捉摸。因此，我们选择了一种结合生化分离/表征和关键酶基因敲除的方法来帮助实现这一搜索。人类基因组计划的完成和质谱技术的进步为推动脂质抗原领域的发展提供了框架，并有可能确定一些最复杂的免疫相关疾病的新治疗方法。更重要的是，该项目将为细胞脂质组学研究提供早期见解，特别关注糖脂的重要免疫功能。人类基因组中超过10%的基因用于脂质代谢；因此，本项目获得的知识和经验可能对功能脂质组学的研究具有深远的意义，这是一个与蛋白质组学和基因组学相比重要但鲜为人知的领域。公共卫生相关性：NKT淋巴细胞是先天免疫的重要组成部分，可以启动适应性免疫反应并调节免疫结果。了解NKT细胞天然配体的特性是研究NKT细胞在病理生理条件下调控的前提。我们的长期目标是阐明NKT细胞天然配体生物合成途径的分子机制，并确定可药物调节的靶点。该项目的重要临床益处是：1)脂质代谢干扰药物在NKT细胞免疫调节中的新治疗应用；2)鉴定新的天然NKT配体作为自身免疫性疾病和癌症的免疫治疗靶点。