Project description:Absent in melanoma 2 (AIM2) is a cytosolic dsDNA sensor that has been broadly studied for its role in inflammasome assembly and innate immune defense against intracellular pathogens. However, very little is known about the function of AIM2 in adaptive immune cells. The purpose of this study was to investigate whether AIM2 has a cell-intrinsic role in CD4+ T cell differentiation or function. We found that AIM2 is expressed in both human and mouse CD4+ T cells and that its expression is affected by T cell receptor (TCR) activation. AIM2-deficient (Aim2-/-) mouse CD4+ T cells upregulate the expression of regulatory T cell (Treg)-associated genes, both in unstimulated conditions and after TCR activation. Naïve CD4+ T cells from Aim2-/- mice also show a higher tendency to differentiate into FOXP3+ cells in vitro, while their capacity to differentiate into Th1 or Th17 cells remains unaltered. In agreement with these data, in a T cell transfer model of colitis, Aim2-/- naïve T cells induce ameliorated disease and also display a higher ability to differentiate into FOXP3+ cells. Our results suggest that AIM2 negatively regulates FOXP3 expression and Treg cell differentiation. We show that AIM2 function is not confined to innate immune cells but is also important in adaptive CD4+ T cells. Our data identify AIM2 as a regulator of Treg cell differentiation and therefore as a potential intervention target for restoring T cell homeostasis.
Project description:Absent in melanoma 2 (AIM2) is a cytosolic dsDNA sensor that has been broadly studied for its role in inflammasome assembly. However, little is known about the function of AIM2 in adaptive immune cells. The purpose of this study was to investigate whether AIM2 has a cell-intrinsic role in CD4+ T cell differentiation or function. We found that AIM2 is expressed in both human and mouse CD4+ T cells and that its expression is affected by T cell receptor (TCR) activation. Naïve CD4+ T cells from AIM2-deficient (Aim2-/-) mice showed higher ability to maintain forkhead box P3 (FOXP3) expression in vitro, while their capacity to differentiate into T helper (Th)1, Th2 or Th17 cells remained unaltered. Transcriptional profiling by RNA sequencing showed that AIM2 might affect regulatory T cell (Treg) stability not by controlling the expression of Treg signature genes, but through the regulation of the cell's metabolism. In addition, in a T cell transfer model of colitis, Aim2-/--naïve T cells induced less severe body weight loss and displayed a higher ability to differentiate into FOXP3+ cells in vivo. In conclusion, we show that AIM2 function is not confined to innate immune cells but is also important in CD4+ T cells. Our data identify AIM2 as a regulator of FOXP3+ Treg cell differentiation and as a potential intervention target for restoring T cell homeostasis.
Project description:In this study, we compared the proteomes of mouse CD4+Foxp3+ regulatory T cells (Treg) and CD4+Foxp3- conventional T cells (Tconv) in order to build a data set of proteins differentially regulated in these two cell populations. The data set contains mass spectrometry results from the analysis of 7 biological replicates of Treg/Tconv cell samples purified by flow cytometry, each experiment performed from a pool of 4-5 mice. Global proteomic analysis of each sample was performed by single-run nanoLC-MS/MS, using chromatographic separation of peptides on 50cm C18 reverse-phase columns, with either a 480min gradient on LTQ-Velos orbitrap mass spectrometer (replicates 1 and 2) or a 300min gradient on Q-Exactive orbitrap mass spectrometer (replicates 3-7). Several MS injection replicates were performed for some experiments, leading to 27 raw files composing the data set. The detailed description of each analysis (file name, sample type, biological replicate number, MS technical replicate number, MS instrument used, sample name in MaxQuant ouput) is given in the table “Files list.txt”.
Project description:We previously found that NF-kB inducing kinase (NIK) overexpression in T cells via CD4 promoter driven transgene induction caused lethal autoimmunity in mice. Autoimmunity was associated with increased conventional T cell effector function and decreased regulatory T cell (Foxp3+CD4+) suppression. The goal in this study was to elucidate global transcriptional changes in Foxp3+CD4+ and Foxp3-CD4+ T cells intrinsically caused by chronic NIK overexpression in these cell types.
Project description:We previously found that NF-kB inducing kinase (NIK) overexpression in T cells via CD4 promoter driven transgene induction caused lethal autoimmunity in mice. Autoimmunity was associated with increased conventional T cell effector function and decreased regulatory T cell (Foxp3+CD4+) suppression. The goal in this study was to elucidate global transcriptional changes in Foxp3+CD4+ and Foxp3-CD4+ T cells intrinsically caused by chronic NIK overexpression in these cell types. Total RNA from FACS-sorted NIKtg and WT Foxp3RFP+CD4+ and Foxp3RFP-CD4+ harvested from NIKtg/CD4Cre/Foxp3RFP + WT/Thy1.1/Foxp3RFP mixed bone marrow chimeric mice, >8 weeks after bone marrow reconstitution.
Project description:CD4(+)Foxp3(+) regulatory T (Treg) cells originate primarily from thymic differentiation, but conversion of mature T lymphocytes to Foxp3 positivity can be elicited by several means, including in vitro activation in the presence of TGF-beta. Retinoic acid (RA) increases TGF-beta-induced expression of Foxp3, through unknown molecular mechanisms. We showed here that, rather than enhancing TGF-beta signaling directly in naive CD4(+) T cells, RA negatively regulated an accompanying population of CD4(+) T cells with a CD44(hi) memory and effector phenotype. These memory cells actively inhibited the TGF-beta-induced conversion of naive CD4(+) T cells through the synthesis of a set of cytokines (IL-4, IL-21, IFN-gamma) whose expression was coordinately curtailed by RA. This indirect effect was evident in vivo and required the expression of the RA receptor alpha. Thus, cytokine-producing CD44(hi) cells actively restrain TGF-beta-mediated Foxp3 expression in naive T cells, and this balance can be shifted or fine-tuned by RA.
Project description:CD4(+)Foxp3(+) regulatory T (Treg) cells originate primarily from thymic differentiation, but conversion of mature T lymphocytes to Foxp3 positivity can be elicited by several means, including in vitro activation in the presence of TGF-beta. Retinoic acid (RA) increases TGF-beta-induced expression of Foxp3, through unknown molecular mechanisms. We showed here that, rather than enhancing TGF-beta signaling directly in naive CD4(+) T cells, RA negatively regulated an accompanying population of CD4(+) T cells with a CD44(hi) memory and effector phenotype. These memory cells actively inhibited the TGF-beta-induced conversion of naive CD4(+) T cells through the synthesis of a set of cytokines (IL-4, IL-21, IFN-gamma) whose expression was coordinately curtailed by RA. This indirect effect was evident in vivo and required the expression of the RA receptor alpha. Thus, cytokine-producing CD44(hi) cells actively restrain TGF-beta-mediated Foxp3 expression in naive T cells, and this balance can be shifted or fine-tuned by RA. All gene expression profiles were obtained from highly purified T cell populations sorted by flow cytometry. To reduce variability, cells from multiple mice were pooled for sorting, and replicates were generated for essentially all groups. RNA from 0.5-3 x 105 cells was amplified, labeled, and hybridized to Affymetrix M430v2 microarrays. Raw data were preprocessed with the RMA algorithm in GenePattern, and averaged expression values were used for analysis.
Project description:The objective of the present study was to characterize the phenotype of CD4+CD25+Foxp3+ regulatory T cells (Tregs) in the course of parasitic Plasmodium yoelii (P .yoelii) infection of BALB/c mice. Therefore we performed microarray expression analysis of CD4+CD25+Foxp3+ Tregs isolated by FACS from spleens of non-infected mice and from spleens of mice infected with P. yoelii 3 days and 5 days post infection. By comparing the gene expression profiles, we were able to identify molecules which were differentially expressed by Tregs during parasitic infection and thereby might be involved in their immune-suppressive function. Moreover, we included CD4+CD25-Foxp3- T cells from spleens of non-infected and P. yoelii-infected mice in our analysis. It was proposed that immune-suppressive CD4+CD25-Foxp3- T cells might be induced during Plasmodium infection of mice. Thus, detailed gene expression data of these cells in comparison to CD4+CD25+Foxp3+ Tregs would contribute a better understanding in the phenotype. FACS sorted CD4+CD25+Foxp3+ Tregs and CD4+CD25-Foxp3- T cells from pooled spleens of non-infected Foxp3/ eGFP mice (served as reference) and from pooled spleens of P. yoelii infected Foxp3/ eGFP mice 3 days and 5 days post infection were analyzed as single probes.