Project description:Memory T cells provide rapid and long-term protection against infection and tumors. The memory CD8+ T cell repertoire contains phenotypically and transcriptionally heterogeneous subsets with specialized functions and recirculation patterns. While these T cell populations have been well characterized in terms of differentiation potential and function, the epigenetic changes underlying memory T cell fate determination and tissue-residency remain largely unexplored. Here, we examined the single-cell chromatin landscape of CD8+ T cells over the course of acute viral infection. We reveal an early bifurcation of memory precursors displaying distinct chromatin accessibility and define epigenetic trajectories that lead to a circulating (TCIRC) or tissue-resident memory T (TRM) cell fate. While TRM cells displayed a conserved epigenetic signature across organs, we demonstrate that these cells exhibit tissue-specific signatures and identify transcription factors that regulate TRM cell populations in a site-specific manner. Moreover, we demonstrate that TRM cells and exhausted T (TEX) cells are distinct epigenetic lineages that are distinguishable early in their differentiation. Together, these findings show that TRM cell development is accompanied by dynamic alterations in chromatin accessibility that direct a unique transcriptional program resulting in a tissue-adapted and functionally distinct T cell state.
Project description:This SuperSeries is composed of the following subset Series: GSE13914: Molecular profiling of breast cancer cell lines defines relevant tumor models (aCGH) GSE15361: Molecular profiling of breast cancer cell lines defines relevant tumor models (gene expression) Refer to individual Series
Project description:Human skin harbors two major T cell compartments of equal size that are distinguished by expression of the chemokine receptor CCR8. In vitro studies have demonstrated that CCR8 expression is under strict control of T cell antigen receptor (TCR)-engagement and the skin tissue microenvironment. We here examined the relationship between CCR8+ and CCR8− T cells. Phenotypic, functional, and transcriptomic analyses revealed that CCR8+ skin T cells bear all the hallmarks of resident memory T (TRM) cells, including homeostatic proliferation in response to IL-7 and IL-15, surface expression of tissue-localization (CD103) and -retention (CD69) markers, low levels of inhibitory receptors (PD-1, Tim-3, LAG-3), and a lack of senescence markers (CD57, KLRG1). In contrast, CCR8− skin T cells are heterogeneous and comprise variable numbers of exhausted (PD-1+), senescent (CD57+, KLRG1+), and effector (T-bethi, Eomeshi) T cells. Importantly, conventional and high-throughput analyses of expressed T cell receptor beta-chain (TRB) gene rearrangement sequences showed that the two skin memory T cell compartments distinguished by CCR8 expression are clonotypically distinct, suggesting that they are produced in response to separate antigenic challenges and distinct stimulatory conditions. Moreover, the phenotypic profiles of these populations were stable in vitro and the presence of similar levels of telomere erosion excludes the possibility of a linear differentiation pathway. In conclusion, CCR8 marks skin-specific, long-lived memory T cells. Therefore, we propose that CCR8+ T cells should be targeted in future skin vaccination research.
Project description:The therapeutic use of regulatory T cells (Tregs) in patients with autoimmune disorders has been hampered by the biological variability of memory Treg populations in the peripheral blood. In this study, we reveal through a combination of quantitative proteomic, multiparametric flow cytometry, RNA-seq data analysis and functional assays, that CD49f is heterogeneously expressed among human Tregs and impacts their immunomodulatory function. High expression of CD49f defines a subset of dysfunctional Tregs in the human blood characterized by a Th17-like phenotype and impaired suppressive capacity. CD49f is similarly distributed between naïve and memory Tregs and impacts the expression of CD39, CTLA-4, FoxP3 and CCR6 specifically in the memory compartment. Accumulation of CD49f high memory Tregs in the blood of ulcerative colitis patients correlates with disease severity. Our results highlight important considerations for Treg immunotherapy design in patients with inflammatory bowel disease which could possibly extend to other autoimmune disorders.