Progenitor Cells for High Endothelium in the Immune Response

项目概要/摘要 高内皮微静脉（HEV）是淋巴细胞进入淋巴组织的专门的毛细血管后门户 和慢性炎症的部位它们调节免疫细胞在生理和 包括自身免疫性疾病和癌症的病理环境。免疫组织化学淋巴结引流部位的HEV 挑战广泛增殖，以支持增强淋巴细胞募集，但内皮前体细胞 导致高内皮细胞和控制其增殖和分化的分子途径 不清楚。我们的转录组学和免疫学研究表明，毛细血管内皮细胞（CapEC）表达 与干细胞和祖细胞经典相关的多种标志物，导致毛细血管 表型EC包括促成HEV干细胞样血液内皮祖细胞群 在免疫反应期间扩张。根据目标1，我们将采用最先进的单细胞 免疫荧光和高维质量标记（CyTOF）流式细胞术，以揭示EC的多样性 LN和免疫细胞募集的淋巴外部位的亚群，定义了动力学和亚群特异性 它们对免疫挑战的增殖反应，并揭示了过渡性细胞出现的时间过程。 表型导致功能性HEV的扩增和成熟。弹道分析会显示 鉴定的亚群（包括鉴定的祖细胞）和免疫荧光的发育关系 组织学和共焦组织成像将确定它们在脉管系统内的位置。目标2：创新的命运 作图方法将阐明BEC亚群之间的同源物-产物关系， 前体对毛细血管和高内皮的贡献。目的3将应用转录谱诱导 EC亚群与泛EC和新型毛细血管EC特异性诱导基因靶向系统的组合， 定义HEV稳态的分子机制和调节祖细胞活化的途径， 在免疫应答中的扩增和对HEV扩增的贡献。 血液内皮细胞亚群及其对免疫应答的综合表型分析将 开辟了血管生物学和免疫学的新研究领域。阐明的机制 内皮细胞特化和稳态，包括调节内皮细胞的机制， 淋巴细胞运输，将导致新的目标和方法，用于控制自身免疫性炎症和 用于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.