Analysis of vascular Galectin-9 as an immunomodulator of B-cell activity

血管 Galectin-9 作为 B 细胞活性免疫调节剂的分析

• 批准号: 9807300
• 负责人: CHARLES J DIMITROFF
• 金额: $ 17.97万
• 依托单位: FLORIDA INTERNATIONAL UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-15 至 2021-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9807300
• 关键词: Adhesions; Adhesives; Antibodies; Antibody Formation; Antibody Response; Antigens; Attenuated; Attenuated Vaccines; Autoimmune Diseases; Automobile Driving; B Cell Proliferation; B-Cell Activation; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Biological Assay; Biology; Blood Vessels; CD22 gene; Carbohydrates; Cartoons; Cell Adhesion; Cell Adhesion Molecules; Cell Communication; Cell model; Cell surface; Cells; Data; Development; Endothelial Cells; Endothelium; Foundations; Galactose Binding Lectin; Galactosides; Genes; Goals; Grant; High Endothelial Venule; Homeostasis; Homing; Human; Immune; Immune response; Immunity; Immunology; Immunomodulators; In Situ; Infection; Inhibition of Cell Proliferation; Investigation; Knowledge; Laboratories; Lead; Lectin; Leukocytes; Ligands; Lupus; Lymphoid; Mediator of activation protein; Memory; Memory B-Lymphocyte; Methods; Modeling; Molecular; Mus; Mutant Strains Mice; N-acetyllactosamine; Organ; PTPN6 gene; Peripheral; Physiological; Plasma Cells; Polysaccharides; Positioning Attribute; Proteins; Protocols documentation; Publishing; Receptors, Antigen, B-Cell; Regulation; Role; Signal Transduction; Structure; Structure of germinal center of lymph node; Supporting Cell; Therapeutic; Tissues; Tonsil; Vaccination; Vascular Endothelial Cell; blood group; cytokine; experience; high risk; immunoregulation; in vivo; innovation; insight; lymph nodes; mouse model; novel; novel therapeutics; peripheral tolerance; recruit; therapy design; transcriptome sequencing

PROJECT ABSTRACT Development of effective antibody (Ab) responses is critically dependent on the recruitment of naïve B cells into secondary lymphoid organs and, upon antigen activation, their coordinated differentiation into germinal center (GC) B cells to memory B cells and Ab-producing plasma cells. Knowing which mechanistic factors control B cell subset transition with the therapeutic goal of Ab-boosting or -attenuating activity, however, is still poorly understood. Exciting new published data from our laboratory highlight striking differences in the glycomic signatures of human naïve, GC and memory B cell subsets featured by either i-linear or I-branched poly-N-acetyllactosamines (poly-LacNAcs). Whereas GC B cells express mainly I-branched poly-LacNAcs, naïve/memory B cells display principally i-linear poly-LacNAcs, which enable robust binding to immuno- modulator, galectin (Gal)-9. Gal-9-binding causes downstream inhibition of cell proliferation, activation and signaling related to BCR-engagement while, interestingly, evoking a pro-survival activity. Given the selective Gal-9-binding to naive/memory B cells, we speculate that Gal-9 serves as a physiologic “tuner” of peripheral B cell activation and B cell reactivity. Other key data on the distribution of Gal-9 in “reactive” lymph node (LN)- like tonsil tissue reveal that, while naïve B cells express endogenous Gal-9, Gal-9 expression is strongest on high endothelial venules (HEV). Since HEVs initiate adhesive contact with circulating naïve/memory B cells and are densely packed in the cortex adjacent to B cell follicles, HEVs are strategically poised to elicit Gal-9- dependent adhesion/regulation. The spatial, cellular and functional control of Gal-9 on B cells in lymphoid organs is still unknown and a major gap in the field of galectin immunology. Our guiding hypothesis is that Gal- 9 on HEV can bind circulating naïve/memory B cells and help recruit them into LNs as well as transmit regulatory signals as B cells traverse the endothelium and enter B cell follicles. In this exploratory proposal, we will examine the function of human endothelial cell (EC)-derived Gal-9 on human naïve B cell adhesion and immunoregulation and will assay for B cell homing to peripheral LNs in the presence/absence of Gal-9. The Specific Aims are: 1.) To study Gal-9-dependent vascular EC – B cell adhesive interactions and 2.) To analyze immunoregulatory effects of Gal-9 expressed by cytokine-activated human ECs on human naïve B cells. We will employ our unique experience and innovative primary human cell models, adhesion assays, mutant mice, gene editing methods to study whether Gal-9 on ECs supports naïve B cell adhesion, LN-homing as well as trigger immunoregulatory activity. These exploratory studies directly challenge current dogma that galectins largely function as immunoregulators, offering an alternative role for Gal-9 in facilitating B cell-EC adhesion, LN-homing and in situ peripheral control of B cell activity. Importantly, our findings will reveal novel targets for modulating B cell immunity and provide necessary data for a grant larger in scope.

项目摘要 有效抗体 (Ab) 反应的发展关键取决于初始 B 细胞的招募 进入次级淋巴器官，并在抗原激活后协调分化为生发细胞 中心 (GC) B 细胞转变为记忆 B 细胞和产生抗体的浆细胞。了解哪些机械因素 然而，以增强抗体或减弱抗体活性为治疗目标的控制 B 细胞亚群转变仍然是一个难题。 不太了解。我们实验室发布的令人兴奋的新数据突显了 人类幼稚细胞、GC 和记忆 B 细胞亚群的糖组特征，以 i 线性或 I 分支为特征 聚-N-乙酰基乳糖胺（聚-LacNAcs）。而 GC B 细胞主要表达 I 分支聚 LacNAc， 幼稚/记忆 B 细胞主要显示 i 线性聚 LacNAc，这使得能够与免疫- 调节剂，半乳糖凝集素 (Gal)-9。 Gal-9 结合导致细胞增殖、活化和下游抑制 有趣的是，该信号传导与 BCR 参与相关，同时还能引发促生存活动。鉴于选择性 Gal-9 与幼稚/记忆 B 细胞结合，我们推测 Gal-9 充当外周 B 细胞的生理“调节器” 细胞活化和 B 细胞反应性。有关 Gal-9 在“反应性”淋巴结 (LN) 中分布的其他关键数据 - 就像扁桃体组织揭示的那样，虽然幼稚 B 细胞表达内源性 Gal-9，但 Gal-9 的表达在 高内皮微静脉（HEV）。由于 HEV 启动与循环的幼稚/记忆 B 细胞的粘附接触 HEV 密集地分布在 B 细胞滤泡附近的皮质中，战略性地准备好引发 Gal-9- 依赖性粘附/调节。 Gal-9 对淋巴 B 细胞的空间、细胞和功能控制 器官仍然未知，是半乳糖凝集素免疫学领域的一个主要空白。我们的指导性假设是 Gal- HEV 上的 9 可以结合循环的幼稚/记忆 B 细胞，帮助将它们募集到 LN 中并传输 当 B 细胞穿过内皮并进入 B 细胞滤泡时发出调节信号。在这个探索性提案中， 我们将检查人内皮细胞 (EC) 来源的 Gal-9 对人幼稚 B 细胞粘附的功能，以及 免疫调节，并将在存在/不存在 Gal-9 的情况下检测 B 细胞归巢至外周 LN。这 具体目标是：1.) 研究 Gal-9 依赖性血管 EC-B 细胞粘附相互作用，以及 2.) 分析细胞因子激活的人 ECs 表达的 Gal-9 对人体的免疫调节作用 幼稚 B 细胞。我们将利用我们独特的经验和创新的原代人体细胞模型、粘附 检测、突变小鼠、基因编辑方法来研究 EC 上的 Gal-9 是否支持幼稚 B 细胞粘附， LN 归巢并触发免疫调节活性。这些探索性研究直接挑战了当前的 半乳糖凝集素主要充当免疫调节剂的教条，为 Gal-9 在促进 B 细胞-EC 粘附、LN 归巢和 B 细胞活性的原位外周控制。重要的是，我们的研究结果将 揭示调节 B 细胞免疫的新靶标，并为更大范围的资助提供必要的数据。