Progenitor Cells for High Endothelium in the Immune Response

项目摘要/摘要 高内皮微静脉(HEV)是淋巴细胞进入淋巴组织的特殊毛细血管后通道 以及血液中的慢性炎症部位。它们调节免疫细胞在生理和免疫系统中的运输 病理环境包括自身免疫性疾病和癌症。HEV在淋巴引流部位的免疫 挑战广泛增殖以支持增强的淋巴细胞募集，但内皮细胞前体 导致高内皮细胞和控制其增殖和分化的分子途径 都不清楚。我们的转录和免疫学研究表明，毛细血管内皮细胞(CapEC)表达 传统上与干细胞和祖细胞相关的多个标记，导致了毛细血管 表型EC包括一群干细胞样血内皮祖细胞，这些细胞对HEV有贡献 在免疫反应过程中扩张。在目标1下，我们将应用最先进的单一电池 免疫荧光和高维质量标记(CyTOF)流式细胞术揭示EC多样性 LN和免疫细胞募集的淋巴外部位的亚群决定了免疫细胞募集的动力学和亚群特异性 它们对免疫攻击的增殖反应，揭示了过渡性T细胞出现的时间过程 导致功能性HEV扩增和成熟的表型。弹道分析将揭示 已鉴定亚群的发育关系，包括已鉴定的祖细胞和免疫荧光 组织学和共聚焦组织成像将确定它们在血管系统中的位置。在目标2中，创新的命运 作图方法将阐明BEC亚群之间的前体-产物关系，并将定义克隆 前体对毛细血管和高级内皮的贡献。AIM 3将应用诱导的转录特征分析 EC亚群与PAN-EC和新型毛细血管EC特异性诱导基因打靶系统相结合 明确HEV动态平衡的分子机制和调节祖细胞激活的途径 HEV在免疫反应中的扩增和贡献。 血液内皮细胞亚群的综合表型分析及其对免疫的反应 开拓血管生物学和免疫学研究的新领域。阐明其致病机制 内皮细胞特化和稳态，包括调控内皮细胞控制的机制 淋巴细胞运输，将导致新的靶点和方法来控制自身免疫性炎症和 疫苗接种和癌症免疫的免疫细胞运输的治疗性调节。

PROJECT SUMMARY / ABSTRACT High endothelial venules (HEV) are specialized post capillary portals for lymphocyte entry into lymphoid tissues and sites of chronic inflammation from the blood. They regulate immune cell trafficking in physiologic and pathologic settings including autoimmune diseases and cancer. HEV in lymph nodes draining sites of immune challenge proliferate extensively to support enhanced lymphocyte recruitment, but the endothelial precursors that give rise to high endothelium and the molecular pathways that control their proliferation and differentiation are unclear. Our transcriptomic and immunologic studies reveal that capillary endothelial cells (CapEC) express multiple markers classically associated with stem and progenitor cells, leading to the hypothesis that capillary phenotype EC comprise a population of stem cell-like blood endothelial progenitors that contribute to HEV expansion during the immune response. Under Aim 1 we will apply state-of-the-art single cell immunofluorescence and high dimensional mass label (CyTOF) flow cytometry to uncover the diversity of EC subsets in LN and in extra lymphoid sites of immune cell recruitment, define the kinetics and subset-specificity of their proliferative responses to immune challenge, and reveal the time course of emergence of transitional phenotypes leading to the amplification and maturation of functional HEV. Trajectory analyses will reveal developmental relationships of identified subsets including identified progenitors, and immunofluorescence histology and confocal tissue imaging will define their location within the vasculature. In Aim 2, innovative fate mapping approaches will elucidate precursor-product relationships among BEC subsets and will define clonal contributions of precursors to capillary and high endothelium. Aim 3 will apply transcriptional profiling of induced EC subsets in combination with pan-EC and novel capillary EC-specific inducible gene targeting systems to define molecular mechanisms of HEV homeostasis and pathways regulating progenitor cell activation, amplification and contribution to HEV expansion in the immune response. Comprehensive phenotypic analyses of blood endothelial cell subsets and their responses to immunization will open up new areas of investigation in vascular biology and immunology. Elucidation of the mechanisms of endothelial cell specialization and homeostasis, including mechanisms regulating endothelial cells that control lymphocyte traffic, will lead to novel targets and approaches for the control of autoimmune inflammation and for therapeutic regulation of immune cell traffic for vaccination and cancer immunity.