Identification and single cell analysis of embryonic lymphoid progenitors that generate neonatal innate T cells

项目摘要 怀孕期间的某些感染与儿童的发育和行为异常有关 后代。母亲体内的显性炎症反应是否会对 后代的免疫系统发育尚不清楚。这种知识上的差距是直接的 这与缺乏对淋巴细胞在胎儿中正常发育的详细了解有关。多么 动物从胎儿期到老年期产生多种免疫细胞亚型仍然是一个活跃的领域 研究中有许多尚未解决的基本问题。特别是，目前还不清楚 免疫系统是一维的，由单个细胞产生的不同类型的细胞的集合 干细胞或b)多层，每一层由功能特化的细胞系统组成 为动物的不同发育年龄量身定做的。我们发现皮肤上的淋巴细胞 (免疫哨兵)预防皮炎所必需的，源于祖细胞具有专门的 只在胚胎中发育的基因程序。重要的是，数据进一步表明， 在单个免疫哨兵出现之前，免疫哨兵的遗传网络在胎儿组织中活跃 胎肝中的造血干细胞(HSC)。一直认为胎儿的HSCs是 所有淋巴细胞的初级干细胞。因此，我们的结果表明存在未被发现的 胚胎先天淋巴祖细胞(EILPs)不同于经典的HSCs或其直系干细胞 子代细胞向淋巴系分化。我们计划识别和表征eILP 通过使用一系列分子信标进行亚型划分，每个分子信标嵌入基因组和 报告eILP的预测基因网络枢纽的活动。胎儿中的稀有细胞，患有 将捕获指定的信标组合，并分析这些候选eILP 在单细胞水平上的分子水平并移植到动物体内以确定它们的生殖力 潜力。候选eILP被预测优先产生粘膜免疫哨兵在 胎儿和新生动物，一旦这些哨兵被制造出来，它们就会长期存在，直到 成人期。这些先天哨兵的缺失或改变会导致组织动态平衡的异常 和炎症性疾病。一旦胚胎造血树被构建， 孕期免疫紊乱可影响先天淋巴细胞的发育 系统评估。

Project Summary Certain infections during pregnancy are linked to developmental and behavioral abnormalities in the offspring. Whether overt inflammatory responses in the mother can have a lasting impact on the development of immune system of the offspring is unknown. This gap in knowledge is directly linked to a lack of detailed insights into how lymphocytes normally develop in the fetus. How animals generate multiple immunocyte subtypes from fetal to aged stages remains an active area of research with many unresolved fundamental questions. In particular, it is unknown whether the immune system is a) one dimensional, a collective of diverse cell types generated from a single stem cell or is b) multi-layered, with each layer made of functionally specialized cell systems tailored to the distinct developmental age of an animal. We discovered that skin lymphocytes (immune sentinels) essential to prevent dermatitis originate from progenitors with dedicated gene programs that only develop in embryos. Importantly, data further suggest that the unique genetic networks of immune sentinels are active in fetal tissues prior to the emergence of a single hematopoietic stem cell (HSC) in the fetal liver. It has been assumed that fetal HSCs are the primary stem cell for all lymphocytes. Our results thus suggest the existence of undiscovered embryonic innate lymphoid progenitors (eILPs) distinct from classical HSCs or their immediate daughter cells primed toward the lymphoid lineage. We plan to identify and characterize eILP subtypes by employing a spectrum of molecular beacons, each embedded in the genome and reporting the activity of predicted gene network hubs of eILPs. Rare cells in the fetus with a specified combination of beacons will be captured and these candidate eILPs will be analyzed molecularly at a single cell level and transplanted into animals to determine their generative potential. Candidate eILPs are predicted to preferentially generate mucosal immune sentinels in fetal and neonatal animals, and once these sentinels are made they persist long term, well into adulthood. Absence or alterations of these innate sentinels results in aberrant tissue homeostasis and inflammatory disorders. Once the embryonic hematopoietic lineage tree is constructed how immune perturbations in pregnancy impact the development of innate lymphocytes can be systematically assessed.