Project description:Neddylation is necessary for activation of Cullin-RING Ligases (CRLs) which degrade various immune regulatory proteins. Our recent study showed that while depletion of neddylation E2-E3 pair Ube2f-Sag in regulatory T cells (Treg cells) had no obvious phenotype, the same depletion of either Ube2m or Rbx1 caused inflammation disorders with different severity. Whether these E2s or E3s compensate each other in functional regulations of Treg cells is, however, previously unknown. In this report, we generated Foxp3Cre;Ube2mfl/fl;Ube2ffl/fl or Foxp3Cre;Rbx1fl/fl;Sagfl/fl double null mice by simultaneously deletion of both neddylation E2s or E3s in Treg cells, respectively. Remarkably, Ube2m&Ube2f double null mice developed much severe autoimmune phenotypes than Ube2m-null mice, indicating Ube2m significantly compensates Ube2f in Treg cells. The minor worsen autoimmune phenotypes seen at very early stage in Rbx1&Sag double null than Rbx1-null mice, is likely due to already severe phenotypes of the later, indicating a minor compensation of Rbx1 for Sag. The RNA profiling-based analyses revealed that up- and down-regulations of few signaling pathways in Treg cells are associated with the severity of autoimmune phenotypes. Finally, severer inflammation phenotypes seen in mice with double E3-null than with double E2-null Treg cells indicate a neddylation-independent mechanism of two E3s, also known to serve as the RING component of CRLs in regulation of Treg cell fitness.
Project description:Neddylation is necessary for activation of Cullin-RING Ligases (CRLs) which degrade various immune regulatory proteins. Our recent study showed that while depletion of neddylation E2-E3 pair Ube2f-Sag in regulatory T cells (Treg cells) had no obvious phenotype, the same depletion of either Ube2m or Rbx1 caused inflammation disorders with different severity. Whether these E2s or E3s compensate each other in functional regulations of Treg cells is, however, previously unknown. In this report, we generated Foxp3Cre;Ube2mfl/fl;Ube2ffl/fl or Foxp3Cre;Rbx1fl/fl;Sagfl/fl double null mice by simultaneously deletion of both neddylation E2s or E3s in Treg cells, respectively. Remarkably, Ube2m&Ube2f double null mice developed much severe autoimmune phenotypes than Ube2m-null mice, indicating Ube2m significantly compensates Ube2f in Treg cells. The minor worsen autoimmune phenotypes seen at very early stage in Rbx1&Sag double null than Rbx1-null mice, is likely due to already severe phenotypes of the later, indicating a minor compensation of Rbx1 for Sag. The RNA profiling-based analyses revealed that up- and down-regulations of few signaling pathways in Treg cells are associated with the severity of autoimmune phenotypes. Finally, severer inflammation phenotypes seen in mice with double E3-null than with double E2-null Treg cells indicate a neddylation-independent mechanism of two E3s, also known to serve as the RING component of CRLs in regulation of Treg cell fitness.
Project description:Cullin-RING Ligases (CRLs), upon activation by neddylation, play the key roles in regulating many biological processes. However, how CRL-neddylation regulates the function of Treg cells remains elusive. Here we show that mice with Treg-specific deletion of Rbx1, a RING component of CRLs required for its activity, developed an early-onset fetal inflammatory disorders and death at day ~25 after birth with disrupted homeostasis and impaired suppressive functions of Treg cells. Specifically, Rbx1 is essential for maintenance of the effector subpopulations in Treg cells, and regulates several inflammatory pathways. Similar phenotypes were seen in mice with deletion of Ube2m, a neddylation E2, in Treg cells, but with much lesser severity. Interestingly, Treg-specific deletion of Rbx2/Sag or Ube2f, the family member of Rbx1 or Ube2m, respectively, had no obvious phenotype. Thus, the Ube2m-Rbx1 axis is required for the maintenance of homeostasis and functions of Treg cells; and Rbx1 has Ube2m-independent roles in the fitness of Treg cells, suggesting a layer of complexity in neddylation activation of CRLs. We use the tranpritome dara to show the mechanism of the function of Rbx1 and Ube2m in Treg cells, also research the relationship of Rbx1 and Ube2m in Treg cells.
Project description:Regulatory T cells (Treg) have been shown to adopt a catabolic metabolic programme with increased capacity for fatty acid oxidation fuelled oxidative phosphorylation (OXPHOS). The role of Foxp3 in this metabolic shift is poorly understood. Here we show that Foxp3 was sufficient to induce a significant increase in the spare respiratory capacity of the cell, the extra OXPHOS capacity available to a cell to meet increased demands on energy in response to work. Foxp3-expressing cells were enhanced in their ability to utilise palmitate for respiration and, in addition, the activity of electron transport complexes I, II and IV were enhanced following Foxp3 expression. Foxp3 also imparts a selective advantage in ATP generation capacity, one that might be exploited as a source of adenosine for functional immunomodulation. In order to explore possible mechanisms for these differences in metabolism we conducted a quantitative proteomics study to compare the contribution of TGFβ and the transcription factor Foxp3 to the Treg proteome. We used quantitative mass spectrometry to examine differences between proteomes of nuclear and cytoplasmic Foxp3-containing CD4+ T cells from various sources with Foxp3- activated CD4 T cells, as well as Treg from human peripheral blood. Gene set enrichment analysis of our proteomic datasets demonstrated that Foxp3 expression is associated with a significant up regulation of several members of the mitochondrial electron transport chain. Not only does Foxp3 influence genes directly concerned with immune function, but also with the energy generating functions of Treg.
Project description:Regulatory T (Treg) cells harbor immune suppressive capacity and are crucial for the maintenance of peripheral tolerance. Treg cells are considered to be heterogenic, where compromised FOXP3 expression results in the generation of exTreg cells. Here we report that the E3 deubiquitinase USP21 prevents the depletion of FOXP3 protein and restricts tissue-resident exTreg cell generation. Mice lacking USP21 in Treg cells display immune disorders characterized by spontaneous T cell activation and excessive T helper type 1 (Th1) skewing. USP21 stabilizes FOXP3 protein by mediating its deubiquitination and therefore helps to maintain the expression of Treg signature genes. Moreover, at inflamed loci, tissue-resident USP21-deficient Treg cells display a Th1-like effector phenotype. Therefore, we demonstrate how USP21 controls the identity of tissue-resident Treg cells by preventing FOXP3 loss.
Project description:Natural CD4+FOXP3+ regulatory T (Treg) cells constitute a unique T-cell lineage that plays a pivotal role in maintaining immune homeostasis and immune tolerance. Recent studies provide evidence for the heterogeneity and plasticity of the Treg cell lineage. However, the fate of human Treg cells after loss of FOXP3 expression and the underlying epigenetic mechanisms remain to be fully elucidated. Here, we compared gene expression profiles and histone methylation status on two histone H3 lysine residues (H3K4me3 and H3K27me3) of expanded FOXP3+ and corresponding FOXP3-losing Treg cells. DGE assay showed that human Treg cells down-regulated Treg signature genes, whereas up-regulated a set of Th lineages-associated genes, especially for Th2, such as GATA3, GFI1 and IL13, after in vitro expansion. Furthermore, we found that reprogramming of Treg cells was associated with histone modifications, as shown by decreased abundance of permissive H3K4me3 within down-regulated Treg signature genes, such as FOXP3, CTLA4 and LRRC32 loci, although with no significant changes in H3K27me3 modification. Thus, our results indicate that human Treg cells could convert into a Th-like cells upon in vitro expansion, displaying a gene expression signature dominated by Th2 lineage associated genes, and the histone methylation might contribute to such conversion. mRNA profiles of in-vitro-expanded FOXP3+ Treg and FOXP3-losing Treg cells generated by deep sequencing.
Project description:Tregs restrain anti-tumor immunity and facilitate the evasion of tumor cells from immune surveillance, thus has long been considered as a promising target for anti-tumor therapy. Recent studies found that excessive type 1 immune responses (mainly mediated by IFN-γ and IL-12 et al.) in the tumor microenvironment drive Treg fragility that downregulates FOXP3 but upregulates IFN-γ, hereby compromises its suppressive function.The expression level of FOXP3 in Treg cells regulates its immunosuppressive function. Therefore, we sorted FOXP3-high and FOXP3-low Treg cells and strived to find their differentially expressed genes and their functional regulatory mechanisms.