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发育和行为异常有关， 后代。母亲的明显炎症反应是否会对 后代免疫系统的发育情况尚不清楚。这种知识上的差距， 这与缺乏对淋巴细胞在胎儿中正常发育的详细了解有关。如何 动物从胎儿到老年阶段产生多种免疫细胞亚型仍然是一个活跃的领域 有许多未解决的基本问题。特别是，不知道是否 免疫系统是a）一维的，由单个细胞产生的不同细胞类型的集合， 干细胞或B）多层，每层由功能特化细胞系统组成 根据动物不同的发育年龄定制。我们发现皮肤淋巴细胞 （免疫哨兵）必不可少的预防皮炎起源于祖细胞与专用 只在胚胎中发育的基因程序。重要的是，数据进一步表明， 免疫哨兵的遗传网络在胎儿组织中是活跃的， 造血干细胞（HSC）在胎儿肝脏。一直认为胎儿HSC是 所有淋巴细胞的原代干细胞。因此，我们的研究结果表明， 与经典HSC不同的胚胎先天淋巴样祖细胞（eILP）或其直接 向淋巴系分化的子细胞。我们计划识别和表征eILP 通过使用分子信标的光谱，每个分子信标嵌入基因组中， 报告eILP的预测基因网络枢纽的活性。胎儿中的稀有细胞 将捕获信标的指定组合，并分析这些候选eILP 在单细胞水平上进行分子检测，并移植到动物体内， 潜力预测候选eILP优先产生粘膜免疫哨兵， 胎儿和新生儿动物，一旦这些哨兵，他们坚持长期，以及进入 成年这些先天性哨兵的缺失或改变导致异常的组织稳态 和炎症性疾病。一旦胚胎造血谱系树构建完成， 妊娠期免疫紊乱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.