Interleukin-2 receptor signaling acts as a checkpoint that shapes the distribution of regulatory T cell subsets (scRNA-Seq)
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ABSTRACT: Regulatory T cells (Tregs) require IL-2 for survival in the periphery, yet how IL-2 shapes Treg heterogeneity remains poorly defined. Here we found that inhibition of IL-2R signaling in post-thymic Tregs leads to a preferential early loss of central Tregs (cTregs). Gene expression of cTregs was more dependent on IL-2R signaling than effector Tregs (eTregs). Unexpectedly, ablation of IL-2R signaling in cTregs resulted in increased proliferation, expression of eTreg genes, and enhanced capacity to develop into eTregs. These findings indicate that physiological amounts of IL-2 act as a checkpoint to maintain cTreg homeostasis and tolerance while restraining their development into eTregs. Nevertheless, direct evaluation of eTregs revealed that loss of IL-2R signaling alters the distribution of eTreg subsets, with increased IFNgR1+ eTregs and CXCR5+ PD-1+ T follicular regulatory (TFR) cells but decreased intestinal RORgt+ TR17 cells. Thus, IL-2R signaling also shapes the development of specialized eTregs subsets.
Project description:Regulatory T cells (Tregs) require IL-2 for survival in the periphery, yet how IL-2 shapes Treg heterogeneity remains poorly defined. Here we found that inhibition of IL-2R signaling in post-thymic Tregs leads to a preferential early loss of central Tregs (cTregs). Gene expression of cTregs was more dependent on IL-2R signaling than effector Tregs (eTregs). Unexpectedly, ablation of IL-2R signaling in cTregs resulted in increased proliferation, expression of eTreg genes, and enhanced capacity to develop into eTregs. These findings indicate that physiological amounts of IL-2 act as a checkpoint to maintain cTreg homeostasis and tolerance while restraining their development into eTregs. Nevertheless, direct evaluation of eTregs revealed that loss of IL-2R signaling alters the distribution of eTreg subsets, with increased IFNgR1+ eTregs and CXCR5+ PD-1+ T follicular regulatory (TFR) cells but decreased intestinal RORgt+ TR17 cells. Thus, IL-2R signaling also shapes the development of specialized eTregs subsets.
Project description:Differentiation and homeostasis of Foxp3 + regulatory T cells (Tregs) are tightly controlled by the interleukin-2 receptor (IL-2R) signaling, yet the mechanisms governing these processes are incompletely understood. Here we report that transcription factor Bach2 attenuates IL-2R signaling to coordinate Treg differentiation and homeostasis by directly repressed CD25 (IL-2Rα). Thus, Bach2 balances IL-2R signaling to orchestrate development and homeostasis of various Treg subsets.
Project description:Regulatory CD4+ T cells (Tregs) are functionally distinct from conventional CD4+ T cells (Tconvs). To understand Treg identity, we have compared by proteomics and transcriptomics human naïve (n) and effector (e)Tregs, Tconvs and transitional FOXP3+ cells. Among these CD4+ T cell subsets, we detected differential expression of 421 proteins and 640 mRNAs, with only 48 molecules shared. Fifty proteins discriminated Tregs from Tconvs. This common Treg protein signature indicates altered signaling by TCR-, TNF receptor-, NFkB-, PI3 kinase/mTOR-, NFAT- and STAT pathways and unique cell biological and metabolic features. Another protein signature uniquely identified eTregs and revealed active cell division, apoptosis sensitivity and suppression of NFkB- and STAT signaling. eTreg fate appears consolidated by FOXP3 outnumbering its partner transcription factors. These features explain why eTregs cannot produce inflammatory cytokines, while transitional FOXP3+ cells can. Our collective data reveal that Tregs protect their identity by a unique “wiring” of signalling pathways
Project description:Regulatory CD4+ T cells (Tregs) are functionally distinct from conventional CD4+ T cells (Tconvs). To understand Treg identity, we compared by proteomics and transcriptomics human naïve (n) and effector (e)Tregs, Tconvs and transitional FOXP3+ cells. Only 12% of 422 differentially expressed proteins was identified as such at the mRNA level, demonstrating the importance of direct proteome measurement. Fifty-one proteins discriminated Tregs from Tconvs. This common Treg protein signature indicates altered signaling by TCR-, TNF receptor-, NFB-, PI3 kinase/mTOR-, NFAT- and STAT pathways, and unique cell biological and metabolic features. Another protein signature uniquely identified eTregs and revealed active cell division, apoptosis sensitivity and suppression of NFB- and STAT signaling. eTreg fate appears consolidated by FOXP3 outnumbering its partner transcription factors. These features explain why eTregs cannot produce inflammatory cytokines, whereas transitional FOXP3+ cells can. Collectively, our data reveal that Treg identity is defined and protected by uniquely “wired” signaling pathways. Associated GEO dataset is available at GSE90600.
Project description:Regulatory CD4+ T cells (Tregs) are functionally distinct from conventional CD4+ T cells (Tconvs). To understand Treg identity, we compared by proteomics and transcriptomics human naïve (n) and effector (e)Tregs, Tconvs and transitional FOXP3+ cells. Only 12% of 422 differentially expressed proteins was identified as such at the mRNA level, demonstrating the importance of direct proteome measurement. Fifty-one proteins discriminated Tregs from Tconvs. This common Treg protein signature indicates altered signaling by TCR-, TNF receptor-, NFB-, PI3 kinase/mTOR-, NFAT- and STAT pathways, and unique cell biological and metabolic features. Another protein signature uniquely identified eTregs and revealed active cell division, apoptosis sensitivity and suppression of NFB- and STAT signaling. eTreg fate appears consolidated by FOXP3 outnumbering its partner transcription factors. These features explain why eTregs cannot produce inflammatory cytokines, whereas transitional FOXP3+ cells can. Collectively, our data reveal that Treg identity is defined and protected by uniquely “wired” signaling pathways.
Project description:Regulatory CD4+ T cells (Tregs) are functionally distinct from conventional CD4+ T cells (Tconvs). To understand Treg identity, we compared by proteomics and transcriptomics human naïve (n) and effector (e)Tregs, Tconvs and transitional FOXP3+ cells. Only 12% of 422 differentially expressed proteins was identified as such at the mRNA level, demonstrating the importance of direct proteome measurement. Fifty-one proteins discriminated Tregs from Tconvs. This common Treg protein signature indicates altered signaling by TCR-, TNF receptor-, NFB-, PI3 kinase/mTOR-, NFAT- and STAT pathways, and unique cell biological and metabolic features. Another protein signature uniquely identified eTregs and revealed active cell division, apoptosis sensitivity and suppression of NFB- and STAT signaling. eTreg fate appears consolidated by FOXP3 outnumbering its partner transcription factors. These features explain why eTregs cannot produce inflammatory cytokines, whereas transitional FOXP3+ cells can. Collectively, our data reveal that Treg identity is defined and protected by uniquely “wired” signaling pathways.
Project description:IL-2R signaling is essential for regulatory T cell (Treg) function. However, the precise contribution for IL-2 during Treg thymic development, peripheral homeostasis, and lineage stability remains unclear. Here we show that IL-2R signaling is essential for thymic Tregs at an early step for expansion/survival and a later step for functional maturation. Using selective deletion of CD25 in peripheral Tregs, we also find that IL-2R signaling was absolutely essential for their persistence whereas Treg lineage stability was IL-2-independent. CD25 knockout peripheral Tregs showed increased apoptosis, oxidative stress, signs of mitochondrial dysfunction, and reduced transcription of key enzymes of lipid and cholesterol biosynthetic pathways. A divergent IL-2 transcriptional signature was noted for thymic Tregs versus peripheral Tregs. These data indicate that IL-2R signaling in the thymus and the periphery leads to distinctive effects on Treg function, where peripheral Treg survival depends on a non-conventional mechanism of metabolic regulation.
Project description:Adoptive transfer of regulatory T cells (Tregs) has been shown to improve alloengraftment in animal models. However, it is technically challenging to expand Tregs ex vivo for the purpose of infusing large numbers of cells in the clinic. We demonstrated an innovative approach to engineer an orthogonal IL-2-IL-2 receptor (IL-2R) pair that selectively interacts with each other and transmits native IL-2 signals, but does not interact with the natural IL-2 or IL-2R counterparts, thereby enabling selective stimulation of target cells in vivo. Here, we introduced this orthogonal IL-2R into Tregs. Upon adoptive transfer in a murine mixed hematopoietic chimerism model, orthogonal IL-2 injection significantly promoted orthogonal IL-2R+Foxp3GFP+CD4+ cell proliferation without increasing other T cell subsets, and facilitated donor hematopoietic cell engraftment followed by acceptance of heart allografts. Our data indicate that selective IL-2 stimulation enabled by cytokine receptor engineering improves Treg potential for the induction of organ transplantation tolerance.
Project description:Thymic-derived natural T regulatory cells (nTregs) are characterized by functional and phenotypic heterogeneity. Recently, a small fraction of peripheral Tregs have been shown to express Klrg1, but it remains unclear the extent Klrg1 defines a unique Treg subset. Here we show that Klrg1+ Tregs represent a terminally differentiated Treg subset derived from Klrg1- Tregs. This subset is a recent antigen-responsive and a highly activated short-lived Treg population that expresses enhanced levels of Treg suppressive molecules and that preferentially resides within mucosal tissues. The development of Klrg1+ Tregs also requires extensive IL-2R signaling. This activity represents a distinct function for IL-2, independent from its contribution to Treg homeostasis and competitive fitness. These and other properties are analogous to terminally differentiated short-lived CD8+ T effector cells. Our findings suggest that an important pathway driving antigen-activated conventional T lymphocytes also operates for Tregs. Gene expression analysis was performed of this and other Treg subsets based on expression of CD62L, CD69, and Klrg1 to define the molecular properties of Klrg1+ Tregs and its relationship to other Treg subsets found in the peripheral immune tissues. Mice were euthanized, spleen cell preparations were made, and each Treg subset was isolated by FACS cell sorting. RNA was immediately prepared for processing.
Project description:Effector regulatory T cells (eTregs) exhibit distinct homeostatic properties and superior suppressor capacities pivotal for controlling immune responses mediated by their conventional T cell counterpart. While the role of microRNAs (miRNAs) in Tregs has been well-established, how miRNAs regulate eTregs remains poorly understood. Here, we demonstrate that miR-15/16 clusters act as key regulators in limiting eTreg responses. Loss of miR-15/16 clusters leads to increased eTreg frequencies with enhanced suppressor function. Consequently, mice with Treg-specific ablation of miR-15/16 clusters display attenuated immune responses during neuroinflammation and upon both infectious and non-infectious challenges. Mechanistically, miR-15/16 clusters exert their regulatory effect in part through repressing IRF4, a transcription factor essential for eTreg differentiation and function. Moreover, miR-15/16 clusters also directly target neuritin, an IRF4-dependent molecule, known for its role in Treg-mediated regulation of plasma cell responses. Together, we identify an miRNA family that controls an important Treg subset and further demonstrate that eTreg responses are tightly regulated at both transcriptional and posttranscriptional levels.