Combined transient ablation and single-cell RNA-sequencing reveals the development of medullary thymic epithelial cells.
Combined transient ablation and single-cell RNA-sequencing reveals the development of medullary thymic epithelial cells.
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DOI：
10.7554/elife.60188
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发表时间：
2020-11-23
期刊：
影响因子：
7.7
通讯作者：
Steinmetz LM
中科院分区：
文献类型：
--
作者：
Wells KL;Miller CN;Gschwind AR;Wei W;Phipps JD;Anderson MS;Steinmetz LM
胸腺髓质上皮细胞 (mTEC) 通过外周自身抗原区室（包括组织特异性抗原 (TSA)）的集体表达来介导自身反应性 T 细胞的阴性选择，从而在中枢免疫耐受中发挥关键作用。最近的研究表明，mTEC 区室内的基因表达模式是异质的，并且包括多种分化的细胞状态。为了进一步定义 mTEC 的发育和髓质上皮谱系关系，我们将谱系追踪和瞬时体内 mTEC 消融的恢复与小家鼠的单细胞 RNA 测序相结合。生物信息学和实验方法的结合揭示了在 Aire 表达之前循环 mTEC 的非干转运扩增群体。我们提出了 mTEC 发育的分支模型，其中转运放大细胞的异质库产生了表达 Aire 和 Ccl21a 的 mTEC 子集。我们进一步使用实验技术表明，在表达 Aire 的发育分支中，随着 Aire 表达的减少，TSA 表达达到峰值，这意味着必须先建立 Aire 表达，然后才能发生 TSA 表达。总的来说，这些数据提供了 mTEC 开发的路线图，并展示了利用体内模型和高维数据集的组合方法的力量。免疫系统中的特殊细胞（称为 T 细胞）通过消灭致病微生物（例如细菌或病毒）来保护身体免受感染。 T 细胞利用其表面称为受体的蛋白质来粘附传染性微生物并将其从体内清除。然而，一些新开发的 T 细胞含有识别并结合体内细胞的受体。如果这些有缺陷的 T 细胞被释放，它们就会攻击健康组织并引起自身免疫性疾病。新的 T 细胞产生后，会被运送到胸部的一个腺体，即胸腺。胸腺中称为 mTEC 的细胞会筛选 T 细胞，寻找可能与身体组织结合的受体。 mTEC 通过向 T 细胞提供体内健康细胞表面常见的蛋白质来实现这一点。如果 T 细胞识别出任何这些“组织特异性蛋白质”，它就会被破坏或在体内发挥新的作用。然而，一些有缺陷的 T 细胞仍然设法逃避检测。揭示为什么会发生这种情况的一种方法是研究 mTEC 是如何发展的。之前的研究表明，mTEC 在达到最终形式之前会经历不同的阶段。然而，这些事件发生的顺序仍不清楚。为了更好地理解这些发育步骤，Wells、Miller 等人。从小鼠胸腺中提取 mTEC 并分析单个细胞的基因组成。这揭示了 mTEC 开发中缺失的环节：一种新型电池，它是最终 mTEC 的直接前身。这些“前身”细胞正在积极生长，这凸显了 mTEC 可以在体内不断生成。 Wells、Miller 等人通过探究 mTEC 中生成组织特异性蛋白质的基因。研究表明，这些蛋白质仅在 mTEC 发育的短期和后期阶段产生。这些发现有助于我们了解 mTEC 如何发展来筛选 T 细胞。绘制这些发育阶段图将更容易识别有缺陷的 T 细胞何时能够逃避 mTEC。这将导致更早发现自身免疫性疾病，从而带来更好的治疗。
Medullary thymic epithelial cells (mTECs) play a critical role in central immune tolerance by mediating negative selection of autoreactive T cells through the collective expression of the peripheral self-antigen compartment, including tissue-specific antigens (TSAs). Recent work has shown that gene-expression patterns within the mTEC compartment are heterogenous and include multiple differentiated cell states. To further define mTEC development and medullary epithelial lineage relationships, we combined lineage tracing and recovery from transient in vivo mTEC ablation with single-cell RNA-sequencing in Mus musculus. The combination of bioinformatic and experimental approaches revealed a non-stem transit-amplifying population of cycling mTECs that preceded Aire expression. We propose a branching model of mTEC development wherein a heterogeneous pool of transit-amplifying cells gives rise to Aire- and Ccl21a-expressing mTEC subsets. We further use experimental techniques to show that within the Aire-expressing developmental branch, TSA expression peaked as Aire expression decreased, implying Aire expression must be established before TSA expression can occur. Collectively, these data provide a roadmap of mTEC development and demonstrate the power of combinatorial approaches leveraging both in vivo models and high-dimensional datasets. Specialized cells in the immune system known as T cells protect the body from infection by destroying disease-causing microbes, such as bacteria or viruses. T cells use proteins on their surface called receptors to stick to infectious microbes and remove them from the body. Some newly developed T-cells, however, contain receptors that recognize and bind to cells that belong in the body. If these faulty T cells are released, they can attack healthy tissues and cause an autoimmune disease. After a new T cell is developed, it gets carried to a gland in the chest known as the thymus. Cells in the thymus called mTECs screen T cells for receptors that may bind to the body’s tissues. mTECs do this by presenting T cells with proteins that are commonly found on the surface of healthy cells in the body. If a T cell recognizes any of these ‘tissue specific proteins’, it is destroyed or given a new role in the body. Some faulty T cells, however, still manage to evade detection. One way to uncover why this might happen is to investigate how mTECs develop. Previous work showed that mTECs transition through various stages before reaching their final form. However, the order in which these events occur remained unclear. To gain a better understanding of these developmental steps, Wells, Miller et al. extracted mTECs from the thymus of mice and analyzed the genetic make-up of individual cells. This uncovered a missing link in mTEC development: a new type of cell that is the immediate predecessor of the final mTEC. These ‘predecessor’ cells were actively growing, highlighting that mTECs can be constantly generated in the body. By probing the genes that generate tissue-specific proteins in mTECs, Wells, Miller et al. revealed that these proteins were only produced for short periods and in the late stages of mTEC development. These findings contribute to our understanding of how mTECs develop to screen T cells. Mapping these developmental stages will make it easier to identify when faulty T cells are able to evade mTECs. This will lead to earlier detection of autoimmune diseases which could result in better treatments.
转录因子LMO4在胸腺发育中的一种新作用，通过与CID2的遗传相互作用2。
影响因子：
2.5
作者：
Michell, Anna C.;Braganca, Jose;Broadbent, Carol;Joyce, Bradley;Franklyn, Angela;Schneider, Juergen E.;Bhattacharya, Shoumo;Bamforth, Simon D.
通讯作者：
Bamforth, Simon D.