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Project description:The integrity of the organism depends on close and dynamic interactions between conventional and regulatory (Treg) T cells. The extracellular signals and signaling events that regulate this crosstalk have been extensively characterized. However, how conventional T cells translate Treg-dependent immunosuppressive signals at the chromatin level remains largely unknown. In differentiating CD4+ T helper (Th) cells, we and others previously reported that transcriptional specificity is largely controlled by heterochromatin-dependent gene silencing. We therefore hypothesized that Treg-mediated T cell suppression could also involve the repressive mark H3K9me3 and the histone-binding factor heterochromatin protein 1 (HP1). Using a bone marrow allograft model, in which graft rejection is coordinated by adoptively-transferred naive CD4+ T cells and can be inhibited by Treg, we show that Treg-dependent suppressive signals indeed mobilize HP1a to repress Th-cell effector genes. Unexpectedly, our screen also revealed that T cells deficient for HP1g or the lysine methyltransferase SUV39H1 are better tolerized than their wild-type counterparts. Mechanistically, our transcriptional and epigenetic profiling identified HP1g as a negative regulator of a network of genes functionally associated with T-cell anergy and exhaustion, including those encoding the transcription factor TOX and the inhibitory receptors PD-1, TIM-3 and LAG-3. In response to T cell receptor engagement, the expression of these immune checkpoints is deregulated in HP1g-deficient cells, thus promoting their better inhibition by Treg. Therefore, we demonstrate that H3K9me3-dependent epigenetic pathways critically regulate Th cell susceptibility to Treg-mediated suppression, and we identify HP1a and HP1g as new epigenetic players whose expression may be manipulated to restore protective immune responses or correct immunopathology, respectively.
2024-11-25 | GSE275355 | GEO
Project description:The integrity of the organism depends on close and dynamic interactions between conventional and regulatory (Treg) T cells. The extracellular signals and signaling events that regulate this crosstalk have been extensively characterized. However, how conventional T cells translate Treg-dependent immunosuppressive signals at the chromatin level remains largely unknown. In differentiating CD4+ T helper (Th) cells, we and others previously reported that transcriptional specificity is largely controlled by heterochromatin-dependent gene silencing. We therefore hypothesized that Treg-mediated T cell suppression could also involve the repressive mark H3K9me3 and the histone-binding factor heterochromatin protein 1 (HP1). Using a bone marrow allograft model, in which graft rejection is coordinated by adoptively-transferred naive CD4+ T cells and can be inhibited by Treg, we show that Treg-dependent suppressive signals indeed mobilize HP1a to repress Th-cell effector genes. Unexpectedly, our screen also revealed that T cells deficient for HP1g or the lysine methyltransferase SUV39H1 are better tolerized than their wild-type counterparts. Mechanistically, our transcriptional and epigenetic profiling identified HP1g as a negative regulator of a network of genes functionally associated with T-cell anergy and exhaustion, including those encoding the transcription factor TOX and the inhibitory receptors PD-1, TIM-3 and LAG-3. In response to T cell receptor engagement, the expression of these immune checkpoints is deregulated in HP1g-deficient cells, thus promoting their better inhibition by Treg. Therefore, we demonstrate that H3K9me3-dependent epigenetic pathways critically regulate Th cell susceptibility to Treg-mediated suppression, and we identify HP1a and HP1g as new epigenetic players whose expression may be manipulated to restore protective immune responses or correct immunopathology, respectively.
2024-11-25 | GSE246827 | GEO
Project description:Heterochromatin-dependent gene silencing controls CD4 T cell response to Treg-mediated suppression.
| PRJNA1034951 | ENA
Project description:Heterochromatin-dependent gene silencing controls CD4 T cell response to Treg-mediated suppression [Tmem]
| PRJNA1150523 | ENA
Project description:Heterochromatin-dependent gene silencing controls CD4 T cell response to Treg-mediated suppression [ATAC-seq]
| PRJNA1034955 | ENA
Project description:Mutations in the tumour suppressor gene BRCA1 lead to breast and/or ovarian cancer. Here we show that loss of Brca1 in mice results in transcriptional de-repression of the tandemly repeated satellite DNA. Brca1 deficiency is accompanied by a reduction of condensed DNA regions in the genome and loss of ubiquitylation of histone H2A at satellite repeats. BRCA1 binds to satellite DNA regions and ubiquitylates H2A in vivo. Ectopic expression of H2A fused to ubiquitin reverses the effects of BRCA1 loss, indicating that BRCA1 maintains heterochromatin structure via ubiquitylation of histone H2A. Satellite DNA de-repression was also observed in mouse and human BRCA1-deficient breast cancers. Ectopic expression of satellite DNA can phenocopy BRCA1 loss in centrosome amplification, cell-cycle checkpoint defects, DNA damage and genomic instability. We propose that the role of BRCA1 in maintaining global heterochromatin integrity accounts for many of its tumour suppressor functions.
| S-EPMC3240576 | biostudies-literature
Project description:BackgroundIn humans and mice naturally occurring CD4(+)CD25(+) regulatory T cells (nTregs) are a thymus-derived subset of T cells, crucial for the maintenance of peripheral tolerance by controlling not only potentially autoreactive T cells but virtually all cells of the adaptive and innate immune system. Recent work using Dicer-deficient mice irrevocably demonstrated the importance of miRNAs for nTreg cell-mediated tolerance.Principal findingsDNA-Microarray analyses of human as well as murine conventional CD4(+) Th cells and nTregs revealed a strong up-regulation of mature miR-155 (microRNA-155) upon activation in both populations. Studying miR-155 expression in FoxP3-deficient scurfy mice and performing FoxP3 ChIP-Seq experiments using activated human T lymphocytes, we show that the expression and maturation of miR-155 seem to be not necessarily regulated by FoxP3. In order to address the functional relevance of elevated miR-155 levels, we transfected miR-155 inhibitors or mature miR-155 RNAs into freshly-isolated human and mouse primary CD4(+) Th cells and nTregs and investigated the resulting phenotype in nTreg suppression assays. Whereas miR-155 inhibition in conventional CD4(+) Th cells strengthened nTreg cell-mediated suppression, overexpression of mature miR-155 rendered these cells unresponsive to nTreg cell-mediated suppression.ConclusionInvestigation of FoxP3 downstream targets, certainly of bound and regulated miRNAs revealed the associated function between the master regulator FoxP3 and miRNAs as regulators itself. miR-155 is shown to be crucially involved in nTreg cell mediated tolerance by regulating the susceptibility of conventional human as well as murine CD4(+) Th cells to nTreg cell-mediated suppression.
| S-EPMC2743997 | biostudies-literature
Project description:The integrity of the organism depends on close and dynamic interactions between conventional and regulatory (Treg) T cells. The extracellular signals and signaling events that regulate this crosstalk have been extensively characterized. However, how conventional T cells translate Treg-dependent immunosuppressive signals at the chromatin level remains largely unknown. In differentiating CD4+ T helper (Th) cells, we and others previously reported that transcriptional specificity is largely controlled by heterochromatin-dependent gene silencing. We therefore hypothesized that Treg-mediated T cell suppression could also involve the repressive mark H3K9me3 and the histone-binding factor heterochromatin protein 1 (HP1). Using a bone marrow allograft model, in which graft rejection is coordinated by adoptively-transferred naive CD4+ T cells and can be inhibited by Treg, we show that Treg-dependent suppressive signals indeed mobilize HP1a to repress Th-cell effector genes. Unexpectedly, our screen also revealed that T cells deficient for HP1g or the lysine methyltransferase SUV39H1 are better tolerized than their wild-type counterparts. Mechanistically, our transcriptional and epigenetic profiling identified HP1g as a negative regulator of a network of genes functionally associated with T-cell anergy and exhaustion, including those encoding the transcription factor TOX and the inhibitory receptors PD-1, TIM-3 and LAG-3. In response to T cell receptor engagement, the expression of these immune checkpoints is deregulated in HP1g-deficient cells, thus promoting their better inhibition by Treg. Therefore, we demonstrate that H3K9me3-dependent epigenetic pathways critically regulate Th cell susceptibility to Treg-mediated suppression, and we identify HP1a and HP1g as new epigenetic players whose expression may be manipulated to restore protective immune responses or correct immunopathology, respectively.
2024-11-25 | GSE246828 | GEO
Project description:The integrity of the organism depends on close and dynamic interactions between conventional and regulatory (Treg) T cells. The extracellular signals and signaling events that regulate this crosstalk have been extensively characterized. However, how conventional T cells translate Treg-dependent immunosuppressive signals at the chromatin level remains largely unknown. In differentiating CD4+ T helper (Th) cells, we and others previously reported that transcriptional specificity is largely controlled by heterochromatin-dependent gene silencing. We therefore hypothesized that Treg-mediated T cell suppression could also involve the repressive mark H3K9me3 and the histone-binding factor heterochromatin protein 1 (HP1). Using a bone marrow allograft model, in which graft rejection is coordinated by adoptively-transferred naive CD4+ T cells and can be inhibited by Treg, we show that Treg-dependent suppressive signals indeed mobilize HP1a to repress Th-cell effector genes. Unexpectedly, our screen also revealed that T cells deficient for HP1g or the lysine methyltransferase SUV39H1 are better tolerized than their wild-type counterparts. Mechanistically, our transcriptional and epigenetic profiling identified HP1g as a negative regulator of a network of genes functionally associated with T-cell anergy and exhaustion, including those encoding the transcription factor TOX and the inhibitory receptors PD-1, TIM-3 and LAG-3. In response to T cell receptor engagement, the expression of these immune checkpoints is deregulated in HP1g-deficient cells, thus promoting their better inhibition by Treg. Therefore, we demonstrate that H3K9me3-dependent epigenetic pathways critically regulate Th cell susceptibility to Treg-mediated suppression, and we identify HP1a and HP1g as new epigenetic players whose expression may be manipulated to restore protective immune responses or correct immunopathology, respectively.
2024-11-25 | GSE246829 | GEO
Project description:Measuring regulatory T cell suppression provides important insight into T cell dysfunction in autoimmune disease. However, to date, suppression assays are limited by the requirement for freshly isolated cells, and significant cell numbers. Here, we present a novel and rapid in vitro assay using effector T cell surface expression of both CD25 and CD134 as a surrogate marker of regulatory T cell-mediated suppression. This surface marker-based suppression assay works for frozen samples and for samples with limited cell numbers. It is also shorter taking two days to complete compared to the four days required for proliferation-based assays. Furthermore, this assay works with both in vitro expanded and natural Tregs, as well as anti-CD3/anti-CD28 bead-based and APC stimulation conditions. In conclusion, we have developed and validated a new suppression assay for cryopreserved samples with limited cell numbers that may be helpful to investigate T cell regulation in the context of infection or autoimmune diseases.
| S-EPMC5573621 | biostudies-literature