Manipulating & imaging nutrient micro-milieux as B cells effect humoral immunity

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• 批准号: 10529278
• 负责人: Mark R Boothby
• 金额: $ 52.54万
• 依托单位: VANDERBILT UNIVERSITY MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-12-01 至 2024-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10529278
• 关键词: Affect; Affinity; Amino Acids; Animal Experiments; Antibodies; Antibody Response; B Cell Proliferation; B cell differentiation; B-Lymphocytes; Biological; Blood Circulation; Cell Differentiation process; Cell physiology; Cells; Chromatin; Complex; Critical Illness; Data; Defect; Development; Diet; Effectiveness; Elements; Endocrine; Environment; Epigenetic Process; Equilibrium; Experimental Models; FRAP1 gene; Gene Expression Regulation; Generations; Glucagon Receptor; Glucose; Glutamates; Glutaminase; Glutamine; Haptens; Health; Histones; Human; Humoral Immunities; Hypoxia; IgE; IgG1; Image; Immune; Immune response; Immunity; Immunization; Immunoglobulin Class Switching; Impairment; In Vitro; Infection; Link; Lymphocyte; Lymphocyte Function; Lymphoid; Lymphoid Follicle; Lysine; Malnutrition; Malpighian corpuscles; Mass Spectrum Analysis; Mature B-Lymphocyte; Measures; Mediator; Memory; Memory B-Lymphocyte; Metabolic; Metabolism; Methylation; Microanatomy; Microbe; Modeling; Molecular; Nature; Nutrient; Nutritional status; Organ; Outcome; Patients; Pattern; Permeability; Physiological; Plasma Cells; Precursor B-Lymphoblast; Process; Proliferating; Protein Deficiency; Proteins; Regulation; Reporting; Rodent; Scientist; Set protein; Signal Pathway; Signal Transduction; Spleen; Structure of germinal center of lymph node; T-Lymphocyte; Testing; Vaccination; Vaccines; Venous; Visualization; Work; adaptive immunity; alpha ketoglutarate; cell type; chromatin modification; density; deprivation; electric impedance; experimental study; genomic locus; histone methylation; in vivo; interstitial; loss of function; lymph nodes; lymphocyte proliferation; mass spectrometric imaging; microbiome; novel; novel strategies; nutrition; oxidation; plasma cell differentiation; restraint; sensor; vaccine efficacy; virtual

Project Summary Generating antibodies, refining their qualities, and creating durable humoral memory are crucial parts of adaptive immunity. The capacity of vaccines to protect against microbes draws on each facet of these processes, but even for some approved and useful vaccines the efficacy is needs to be better. Accordingly, it is vital to decipher key cellular and molecular processes that affect antibody (Ab) qualities. Major efforts are directed toward the identification of ways in which intracellular sensors, mediators of intermediary metabolism, and metabolites proper alter immune cell differentiation or function. It has long been known that malnutrition undermines immune defenses against infection, and a body of work has suggested that protein deficiency may decrease effective Ab responses. Nutrient supply is intrinsically linked to intracellular sensors such as mTORC1 and programming of cellular metabolism in immune cells. For instance, experimental models of isolated protein deficiency have documented decreases in venous concentrations of amino acids (a.a.) and lower mTORC1 activity in freshly isolated organs from the malnourished rodents. Our work on mTORC1 in B cells found antibody responses to be altered by B cell-restricted haplo-insufficiency of Raptor, with partially reduced activity similar in magnitude to that reported in the setting of protein deprivation. Moreover, we – and others in parallel – uncovered evidence of variegated hypoxia in the white pulp and lymphoid follicles after immunization and formation of germinal centers. Preliminary in vitro and in vivo experiments provide evidence that (a) glutamine, at the physiological concentration of non-inflamed interstitia, is limiting for fully efficient switching to IgG1 and for plasma cell differentiation, and (b) glutaminolysis (the conversion of glutamine to glutamate, and then α-ketoglutarate) can be limiting for these processes. These findings are the premise for the overarching model of this application: that nutrients may be present in follicles at concentrations where either increases or further decreases alter the nature of the antibody response as it draws on lymphocyte proliferation and function. Accordingly, in Aim 1 we will test the impact on Ab responses of reducing a.a. supply to or utilization by mature B cells. Aim 2 will identify consequences for metabolic and epigenetic programming of the B cells in which glutamine supply or glutaminolysis are restricted, alone or with reduced glucose oxidation capacity. An implication of the model is that increased circulating a.a. – or even just glutamine – could enhance outcomes of immunization. In Aim 3, we will use a newly identified endocrine approach to test if hyperaminoacidemia increases interstitial glutamine and yields greater Ab responses or humoral memory. As a novel facet of the experiments, we will leverage a state-of the-art development in imaging mass spectrometry (IMS) to assess glutamine and selected metabolites in selected lymphoid micro-environments of experimental animals. The expected outcome & impact of the proposed studies are that we will (i) provide a ground-breaking technical advance in application of IMS to biological problems, (ii) elucidate a long-standing issue at the nexus of nutrition and immunity, and (iii) identify a novel means of boosting antibody responses.

项目概要 产生抗体、完善其品质以及创造持久的体液记忆是适应性的关键部分 免疫。疫苗抵御微生物的能力取决于这些过程的各个方面，但即使 对于一些已批准且有用的疫苗，其功效需要更好。因此，破译密钥至关重要 影响抗体 (Ab) 质量的细胞和分子过程。主要努力方向是 识别细胞内传感器、中间代谢介质和代谢物适当的方式 改变免疫细胞的分化或功能。众所周知，营养不良会损害免疫力 防御感染，大量工作表明蛋白质缺乏可能会降低有效抗体 回应。营养供应与细胞内传感器（例如 mTORC1）和细胞内传感器的编程有内在联系。 免疫细胞中的细胞代谢。例如，分离蛋白质缺乏的实验模型 据记录，新鲜血液中氨基酸 (a.a.) 的静脉浓度降低，mTORC1 活性降低 从营养不良的啮齿动物身上分离出器官。我们对 B 细胞中 mTORC1 的研究发现抗体反应是 被 Raptor 的 B 细胞限制性单倍体不足所改变，部分活性降低的程度与此类似 据报道，在蛋白质剥夺的情况下。此外，我们 - 以及其他人 - 发现了证据 免疫后白髓和淋巴滤泡出现杂色缺氧并形成生发中心。 初步的体外和体内实验提供了以下证据：(a) 生理浓度的谷氨酰胺 非发炎间质的减少，限制了完全有效地转换为 IgG1 和浆细胞分化，并且 (b) 谷氨酰胺分解（谷氨酰胺转化为谷氨酸，然后转化为 α-酮戊二酸）可能会限制这些 流程。这些发现是该应用总体模型的前提：营养素可能是 存在于囊泡中的浓度增加或进一步减少都会改变抗体的性质 反应，因为它利用淋巴细胞增殖和功能。因此，在目标 1 中，我们将测试对 Ab 的影响 减少 a.a. 的反应供给成熟 B 细胞或被成熟 B 细胞利用。目标 2 将确定后果 B 细胞的代谢和表观遗传编程，其中谷氨酰胺供应或谷氨酰胺分解受到限制， 单独使用或与降低的葡萄糖氧化能力一起使用。该模型的一个含义是循环量增加。 - 或者 即使只是谷氨酰胺——也可以增强免疫效果。在目标 3 中，我们将使用一种新发现的内分泌激素 测试高氨基酸血症是否会增加间质谷氨酰胺并产生更大的抗体反应的方法或 体液记忆。作为实验的一个新颖方面，我们将利用最先进的成像技术 质谱 (IMS) 评估选定淋巴微环境中的谷氨酰胺和选定代谢物 的实验动物。拟议研究的预期结果和影响是，我们将 (i) 提供 将IMS应用于生物问题的突破性技术进步，（ii）阐明了一个长期存在的问题 结合营养和免疫，以及 (iii) 确定一种增强抗体反应的新方法。