Transcriptional profiling of brain CD4+ and CD8+ TRM cells reveals dominant presence in white and grey matter in Multiple Sclerosis (Location)

The human brain is populated by perivascular CD8+ and CD4+ T cells with a tissue-resident memory T (TRM)-cell phenotype. In multiple sclerosis (MS), these cells associate with white matter (WM) and, to a lesser extent, grey matter (GM) lesions. We here investigated the transcriptional and functional profile of brain-resident T cells. Of n=11 subsequent post-mortem brain donors, we isolated CD8+ and CD4+ effector memory and effector memory re-expressing CD45RA T cells from blood and CD8+ and CD4+ CD69+ T cells from corpus callosum WM and cortical GM. Additionally, brain CD69+ T cells were sorted from subcortical WM, corpus callosum WM, and medulla WM/GM of n=3–5 brain donors as well as from paired normal-appearing WM and GM and from WM and GM lesions of n=6 MS brain donors. In all donors, WM and GM T cells were overwhelmingly CD69+CD103+/-. Bulk RNA sequencing of CD8+ and CD4+ CD69+ T cells revealed TRM-cell signatures, as marked by differential expression of, among others, SELL (CD62L), ITGA1 (CD49a), and S1PR1. Notably, gene expression hardly differed between lesional and normal-appearing WM CD8+ and CD4+ CD69+ T cells in MS brains. Genes up-regulated in brain TRM cells were MS4A1 (CD20) and SPP1 (osteopontin, OPN). OPN is also abundantly expressed by microglia and has been shown to inhibit T-cell activity. In line with the increased presence of OPN in active MS lesions, we noticed a reduced production of the inflammatory cytokines IL-2, TNF, and IFNγ by MS lesion-derived CD8+ and CD4+ T cells ex vivo. This study discloses essential characteristics of human brain CD8+ and CD4+ TRM cells in non-MS and MS post-mortem WM and GM, reports OPN as a generic product of brain-resident immune cells, and shows a tight control of the activation state of TRM cells in MS lesions. Comparative gene expression profiling analysis of bulk RNA-seq data of brain CD8+ CD69+ T cells from subcortical WM, corpus callosum, and medulla oblongata of n=3–5 brain donors. Second dataset of 3.

人类大脑中存在具有组织驻留记忆T（tissue-resident memory T, TRM）细胞表型的血管周围CD8+与CD4+ T细胞。在多发性硬化（multiple sclerosis, MS）患者中，此类细胞与白质（white matter, WM）病灶相关，同时也会少量浸润灰质（grey matter, GM）病灶。本研究针对脑驻留T细胞的转录组与功能特征展开了探究。本研究纳入11例后续尸检脑供者，从其血液中分离出CD8+、CD4+ 效应记忆T细胞以及重新表达CD45RA的效应记忆T细胞，同时从胼胝体白质与皮层灰质中分离出CD8+、CD4+ CD69+ T细胞。此外，我们从3~5例脑供者的皮层下白质、胼胝体白质以及延髓白质/灰质中分选得到脑CD69+ T细胞；同时从6例MS脑供者的配对正常外观白质、正常外观灰质，以及病灶区白质与病灶区灰质中分离此类细胞。所有供者的白质与灰质T细胞均以CD69+CD103+/-表型为主。对CD8+与CD4+ CD69+ T细胞进行批量RNA测序（bulk RNA sequencing），结果显示其具有TRM细胞特征，具体表现为包括SELL（CD62L）、ITGA1（CD49a）以及S1PR1在内的多个基因存在差异表达。值得注意的是，MS患者脑组织中病灶区与正常外观白质的CD8+、CD4+ CD69+ T细胞之间的基因表达几乎无差异。脑TRM细胞中上调表达的基因包括MS4A1（CD20）与SPP1（骨桥蛋白，osteopontin, OPN）。骨桥蛋白（OPN）同样在小胶质细胞中高表达，且已被证实可抑制T细胞活性。鉴于活动性MS病灶中OPN表达水平升高，我们体外实验观察到，从MS病灶分离得到的CD8+、CD4+ T细胞所分泌的炎性细胞因子IL-2、TNF以及IFNγ水平均有所降低。本研究阐明了非MS与MS尸检脑组织白质、灰质中人类脑CD8+、CD4+ TRM细胞的核心特征，证实OPN是脑驻留免疫细胞的通用表达产物，并揭示了MS病灶内TRM细胞激活状态受到严格调控的现象。本研究还对3~5例脑供者皮层下白质、胼胝体及延髓的脑CD8+ CD69+ T细胞的批量RNA测序数据开展比较基因表达谱分析。第二份数据集：3。