Project description:T cell receptor(TCR) engagement in the absence of costimulation leads to a state of T cell tolerance known as anergy. Anergy induction requires new protein synthesis since it is inhibited by cycloheximide. In this experiment, we tried to figure out kinetic properties of the gene expression in anergy induction phase and the subsequent anergy maintenance phase.
Project description:T cell receptor(TCR) engagement in the absence of costimulation leads to a state of T cell tolerance known as anergy. Anergy induction requires new protein synthesis since it is inhibited by cycloheximide. In this experiment, we tried to figure out kinetic properties of the gene expression in anergy induction phase and the subsequent anergy maintenance phase. A.E7 cell, a murine CD4(+) T cell clone, was stimulated with anti-TCR antibody for 0, 2, 4, and 6hrs followed by RNA extraction. For the maintenance phase, A.E7 was stimulated for 16hrs and rested for 5days before RNA extraction.
Project description:Establishment of a diverse B-cell receptor (BCR) repertoire by V(D)J recombination generates autoreactive B-cells that are eliminated by central tolerance in the bone marrow or down-regulate their BCR responsiveness to self-antigen during anergy induction in peripheral B-cells. The loss of anergy combined with hyperactivation of nucleic acid-sensing Toll-like receptors (TLRs) is thought to break B-cell tolerance leading to autoimmunity, although the transcriptional factors controlling these processes are still unknown. Here, we describe a critical role of Ikaros in promoting B-cell anergy and restraining TLR signaling by analyzing mice with specific deletion of Ikaros in mature B-cells, which resulted in systemic autoimmunity. While regulating many anergy-associated genes, Ikaros also activated the Zfp318 gene, implicated in down-tuning of the BCR responsiveness by shifting expression from IgM to IgD in anergic B-cells. TLR signaling was hyperactive in Ikaros-deficient B-cells, which failed to up-regulate feedback inhibitors of the MyD88-NF-?B signaling pathway. Systemic inflammation was lost upon expression of a non-self-reactive BCR or loss of MyD88 in Ikaros-deficient B-cells, which identified Ikaros as a guardian preventing autoimmunity by coordinately regulating anergy induction and TLR signaling.
Project description:T cell anergy is one of the mechanisms contributing to peripheral tolerance, particularly in the context of progressively growing tumors and in tolerogenic treatments promoting allograft acceptance. We recently reported that early growth response gene 2 (Egr2) is a critical transcription factor for the induction of anergy in vitro and in vivo, which was identified based on its ability to regulate the expression of inhibitory signaling molecules diacylglycerol kinase (DGK)-a and -z. We reasoned that other transcriptional targets of Egr2 might encode additional factors important for T cell anergy and immune regulation. Thus, we conducted two sets of genome-wide screens: gene expression profiling of wild type versus Egr2-deleted T cells treated under anergizing conditions, and a ChIP-Seq analysis to identify genes that bind Egr2 in anergic cells. Merging of these data sets revealed 49 targets that are directly regulated by Egr2. Among these are inhibitory signaling molecules previously reported to contribute to T cell anergy, but unexpectedly, also cell surface molecules and secreted factors, including lymphocyte-activation gene 3 (Lag3), Class-I-MHC-restricted T cell associated molecule (Crtam), Semaphorin 7A (Sema7A), and chemokine CCL1. These observations suggest that anergic T cells might not simply be functionally inert, and may have additional functional properties oriented towards other cellular components of the immune system.
Project description:T cell anergy is one of the mechanisms contributing to peripheral tolerance, particularly in the context of progressively growing tumors and in tolerogenic treatments promoting allograft acceptance. We recently reported that early growth response gene 2 (Egr2) is a critical transcription factor for the induction of anergy in vitro and in vivo, which was identified based on its ability to regulate the expression of inhibitory signaling molecules diacylglycerol kinase (DGK)-a and -z. We reasoned that other transcriptional targets of Egr2 might encode additional factors important for T cell anergy and immune regulation. Thus, we conducted two sets of genome-wide screens: gene expression profiling of wild type versus Egr2-deleted T cells treated under anergizing conditions, and a ChIP-Seq analysis to identify genes that bind Egr2 in anergic cells. Merging of these data sets revealed 49 targets that are directly regulated by Egr2. Among these are inhibitory signaling molecules previously reported to contribute to T cell anergy, but unexpectedly, also cell surface molecules and secreted factors, including lymphocyte-activation gene 3 (Lag3), Class-I-MHC-restricted T cell associated molecule (Crtam), Semaphorin 7A (Sema7A), and chemokine CCL1. These observations suggest that anergic T cells might not simply be functionally inert, and may have additional functional properties oriented towards other cellular components of the immune system. T cell-specific Egr2 deletion was mediated by use of a Cre-expressing adenovirus and a CAR Tg x Egr2flox/flox mouse in which CAR is expressed exclusively in the T cell compartment from a Lck promoter/CD2 enhancer cassette. OVA-specific Th1 cell clones were generated from CAR Tg x Egr2flox/flox mice. CAR Tg x Egr2flox/flox Th1 T cells were infected with an empty (EV) or a Cre-expressing adenovirus. Upon confirmation of Egr2 deletion by immunoblot, the T cells were left untreated (Control) or anergized (Anergic) by immobilized anti-CD3 for 16 hours, and microarray was conducted after 1 day of rest in culture medium. The microarray analysis was performed three times using three sets of independently manipulated samples
Project description:Nrn1-/- and Nrn1+/- Thy1.1+ OTII cells were cotransferred with wt Treg cell into TCRa-/- hosts and subjected to soluble OVA peptide i.v. treatment for anergy induction on day 1, 4, and 7 post transfer. Nrn1-/- and Nrn1+/- Thy1.1+ OTII cells were recoverred by cell sorting 13 days after cell transferand subjected to RNA-Sequencing analysis