Single cell RNA-seq of metabolite specific T-cells (MR1-restricted) from adult mouse thymus

Mucosal-Associated Invariant T cells have a unique specificity for the microbial metabolite 5-OP-RU presented by the non-classical presentation molecule MR1. Upon activation, they release cytotoxic mediators and engage an antimicrobial activity. As a subset of T lymphocytes, MAIT development occurs in the thymus where they acquire their effector phenotype under the control of the key transcription factor ZBTB16. This particular maturation process is in contrast with conventional T cells that egress the thymus with a naive phenotype before populating the secondary lymphoid organs, and the molecular events driving the MAIT lineage decision are poorly known. In the present work, we evaluated the transcriptional events and the role of the slam-SAP pathway on the lineage decision of MR1-restricted T cells by single cell RNAseq. MAIT cells undergoing positive selection were FACS-sorted with a MR1:5-OP-RU labeled tetramer, from thymus of wild-type and sapKO mice. Their transcriptomes were captured using a 10x chromium system.黏膜相关恒定T细胞（Mucosal-Associated Invariant T cells，MAIT）对非经典呈递分子MR1所呈递的微生物代谢物5-OP-RU具有独特的特异性。该细胞激活后可释放细胞毒性介质并发挥抗菌活性。作为T淋巴细胞的一个亚群，MAIT细胞的发育过程发生于胸腺，在此期间其在关键转录因子ZBTB16的调控下获得效应表型。这一特殊的成熟过程与常规T细胞存在显著差异：常规T细胞以初始表型迁出胸腺，随后定植于次级淋巴器官。目前，调控MAIT细胞谱系决定的分子事件仍不甚明晰。本研究通过单细胞RNA测序（single cell RNAseq）评估了slam-SAP通路在MR1限制性T细胞谱系决定中的转录调控事件及其作用。研究人员从野生型及sap基因敲除（sapKO）小鼠的胸腺中，利用MR1:5-OP-RU标记的四聚体对经历阳性选择的MAIT细胞进行了流式细胞分选，并通过10x Chromium系统捕获了其转录组信息。