MRNA-seq of thymic epithelial cells from PBS or IL-33 treated thymus
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ABSTRACT: Severe infection commonly results in T cell aging, which leads to impaired pathogen clearance or increased secondary infection in both humans and animals. However, the exact mechanisms remain poorly understood. Here, we demonstrated that severe infection-induced IL-33 production resulted in acute thymic involution-mediated naive T cell aging and impaired host control of infection in mouse disease models of schistosomiasis or sepsis. Furthermore, we illustrated that IL-33 triggered excessive generation of medullary thymic epithelial cell (mTEC) IV (thymic tuft cells) in a Pou2f3-dependent manner, as a consequence, disturbed mTEC/cortical TEC (cTEC) compartment and caused acute thymic involution during severe infection. More importantly, IL-33 deficiency or IL-33 receptor ST2 deficient thymus transplantation rescued T-cell immunity to better control infection in mice. Our findings not only uncover a novel link between severe infection-induced IL-33 and thymic involution-mediated naive T cell aging, but also suggest that targeting IL-33 or ST2 is a promising strategy to rejuvenate T cell immunity to better control severe infection.
Project description:Severe infection commonly results in T cell aging, which leads to impaired pathogen clearance or increased secondary infection in both humans and animals. However, the exact mechanisms remain poorly understood. Here, we demonstrated that severe infection-induced IL-33 production resulted in acute thymic involution-mediated naive T cell aging and impaired host control of infection in mouse disease models of schistosomiasis or sepsis. Furthermore, we illustrated that IL-33 triggered excessive generation of medullary thymic epithelial cell (mTEC) IV (thymic tuft cells) in a Pou2f3-dependent manner, as a consequence, disturbed mTEC/cortical TEC (cTEC) compartment and caused acute thymic involution during severe infection. More importantly, IL-33 deficiency or IL-33 receptor ST2 deficient thymus transplantation rescued T-cell immunity to better control infection in mice. Our findings not only uncover a novel link between severe infection-induced IL-33 and thymic involution-mediated naive T cell aging, but also suggest that targeting IL-33 or ST2 is a promising strategy to rejuvenate T cell immunity to better control severe infection.
Project description:The goal of this study was to determine whether thymic innate lymphoid cells type-2 (ILC2) activation during acute thymic involution is mediated by the alarmins IL-25 and IL-33. For this purpose we sorted thymic ILC2 from WT mice, treated them ex vivo with recombinant IL-25/IL-33 or both for 24 hours, and performed bulk RNA Seq.
Project description:T-cell factor 1 (Tcf-1) expressing CD8 T cells exhibit stem-like self-renewing capacity rendering them key for immune defense against chronic viral infection and cancer. Yet, the signals that promote the formation and maintenance of these memory-like CD8 T cell (CD8ML) remain poorly defined. Studying CD8 T cell differentiation in mice with chronic viral infection we identify the alarmin interleukin-33 (IL-33) as pivotal for the expansion and stem-like functioning of CD8ML as well as for virus control. IL-33 receptor- (ST2-) deficient CD8 T cells exhibit biased end-differentiation and premature loss of Tcf-1. Intriguingly, ST2-deficient CD8ML responses are restored by blockade of type I interferon signaling, suggesting that opposing IFN-I and IL-33 effects control CD8ML formation in chronic infection. IL-33 signals broadly augment chromatin accessibility in CD8ML and determine these cells’ re-expansion potential. Our study identifies the IL-33 – ST2 axis as an important CD8ML-promoting pathway in the context of chronic viral infection.
Project description:T-cell factor 1 (Tcf-1) expressing CD8 T cells exhibit stem-like self-renewing capacity rendering them key for immune defense against chronic viral infection and cancer. Yet, the signals that promote the formation and maintenance of these memory-like CD8 T cell (CD8ML) remain poorly defined. Studying CD8 T cell differentiation in mice with chronic viral infection we identify the alarmin interleukin-33 (IL-33) as pivotal for the expansion and stem-like functioning of CD8ML as well as for virus control. IL-33 receptor- (ST2-) deficient CD8 T cells exhibit biased end-differentiation and premature loss of Tcf-1. Intriguingly, ST2-deficient CD8ML responses are restored by blockade of type I interferon signaling, suggesting that opposing IFN-I and IL-33 effects control CD8ML formation in chronic infection. IL-33 signals broadly augment chromatin accessibility in CD8ML and determine these cells’ re-expansion potential. Our study identifies the IL-33 – ST2 axis as an important CD8ML-promoting pathway in the context of chronic viral infection.
Project description:T-cell factor 1 (Tcf-1) expressing CD8 T cells exhibit stem-like self-renewing capacity rendering them key for immune defense against chronic viral infection and cancer. Yet, the signals that promote the formation and maintenance of these memory-like CD8 T cell (CD8ML) remain poorly defined. Studying CD8 T cell differentiation in mice with chronic viral infection we identify the alarmin interleukin-33 (IL-33) as pivotal for the expansion and stem-like functioning of CD8ML as well as for virus control. IL-33 receptor- (ST2-) deficient CD8 T cells exhibit biased end-differentiation and premature loss of Tcf-1. Intriguingly, ST2-deficient CD8ML responses are restored by blockade of type I interferon signaling, suggesting that opposing IFN-I and IL-33 effects control CD8ML formation in chronic infection. IL-33 signals broadly augment chromatin accessibility in CD8ML and determine these cells’ re-expansion potential. Our study identifies the IL-33 – ST2 axis as an important CD8ML-promoting pathway in the context of chronic viral infection.
Project description:Allergic conjunctivitis is a chronic inflammatory disease that is characterized by severe itch in the conjunctiva; but how neuro-immune interactions shape the pathogenesis of severe itch remains unclear. We identified a subset of memory-type pathogenic Th2 cells that preferentially expressed Il1rl1-encoding ST2 and Calca-encoding calcitonin gene-related peptide (CGRP) in the inflammatory conjunctiva using a single-cell analysis. The IL-33-ST2 axis in memory Th2 cells controlled the axonal elongation of the peripheral sensory C-fiber and the induction of severe itch. Pharmacological blockade and genetic deletion of CGRP signaling in vivo attenuated scratching behavior. The analysis of giant papillae from patients with severe allergic conjunctivitis revealed ectopic lymphoid structure formation with the accumulation of IL-33-producing epithelial cells and CGRP-producing pathogenic CD4+ T cells accompanied by peripheral nerve elongation. Thus, the IL-33-ST2-CGRP axis directs severe itch with neuro-reconstruction in the inflammatory conjunctiva and is a potential therapeutic target for severe itch in allergic conjunctivitis.
Project description:In order to recover from infection, organisms must balance robust immune responses to pathogens with the tolerance of immune-mediated pathology. This balance is particularly critical within the central nervous system, whose complex architecture, essential function, and limited capacity for self-renewal render it susceptible to both pathogen- and immune-mediated pathology. Here, we identify the alarmin IL-33 and its receptor ST2 as critical for host survival to neuroinvasive flavivirus infection. We identify oligodendrocytes as the critical source of IL-33, and microglia as the key cellular responders. Notably, we find that the IL-33/ST2 axis does not impact viral control or adaptive immune responses; rather, it is required to promote the activation and survival of microglia. In the absence of intact IL-33/ST2 signaling in the brain, neuroinvasive flavivirus infection triggered aberrant recruitment of monocyte-derived peripheral immune cells, increased neuronal stress, and neuronal cell death, effects that compromised organismal survival. These findings identify IL-33 as a critical mediator of CNS tolerance to pathogen-initiated immunity and inflammation.
Project description:Given its central role in immune aging, identifying regulators of thymic involution is important. While conventional programmed cell death plays a fundamental role in thymocyte development, how cell death pathways contribute to thymic involution remains unclear. In this study, we found that CD4+CD8+ double positive (DP) thymocytes acquired characteristics of senescence in aged mice undergoing thymic involution, while expression of the m6A methyltransferase METTL3 (enriched in DP cells from young mice) decreased with aging. By conditionally deleting METTL3 in T cells, we revealed a critical role for METTL3 in DP cell survival, and in restraining features of aging in DP thymocytes by preventing ferroptosis signaling, through glutathione peroxidase 4 (GPX4). Mechanistically, GPX4 was maintained by METTL3 at the translational level, independent of its methyltransferase activity. Furthermore, we found that pharmacological inhibition of ferroptosis promoted DP cell survival, and attenuate d features of aging in DP thymocytes. These findings uncover a role for METTL3-regulated ferroptosis in thymic involution, and identify strategies to restore thymic function.
Project description:The effects of IL-33 on ST2+ Treg cells were not studied thouroughly. We FACS-sorted in vitro expanded ST2+ Treg cells from C57BL/6 Foxp3-IRES-mRFP (B6 FIR) mice. We next used RNA-seq techonology to define how recombinant IL-33 (rIL-33) may impact mouse Treg by to assessing the transcriptome of IL-33-stimulated ST2+ Treg cells compared to that of untreated ST2+ Treg cells. Our data revealed that ST2+ Treg stimulated with rIL-33 for 6 hours exhibited increased expression of Il10 and Il13 compared to unstimulated ST2+ Treg cells.
Project description:Severe asthma and sinus disease is a consequence of Type 2 inflammation (T2I), mediated by IL-33 signaling through its membrane-bound receptor, ST2. Soluble (s)ST2 reduces available IL-33 and limits T2I, but little is known about its regulation. We demonstrate that prostaglandin E2 (PGE2) drives production of sST2 to limit features of lung T2I. PGE2 deficient mice display diminished sST2. In humans with severe respiratory T2I, urinary PGE2 metabolites correlate with serum sST2. In mice, PGE2 enhanced sST2 secretion by mast cells (MCs). Mice lacking MCs, ST2 expression by MCs or EP2 receptors by MCs showed reduced sST2 lung concentrations and strong T2I. Recombinant sST2 reduced T2I in mice lacking PGE2 or ST2 expression by MCs back to control levels. PGE2 deficiency also reversed the hyperinflammatory phenotype in mice lacking ST2 expression by MCs. PGE2 thus suppresses T2I through MC-derived sST2, explaining the severe T2I observed in low PGE2 states.