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. Genome-wide analysis of histone H3 K4 and K27 trimethylation in expanded human FOXP3+ Treg cells and FOXP3-losing Treg cells
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:The gene expression profile of peripheral Foxp3+ natural regulatory T cells isolated from Foxp3/EGFP bicistronic mice was compared to that of in vitro-induced regulatory T cells and to CD4+ conventional (Foxp3-) T cells. The role of the regulatory T cell transcription factor Foxp3 in shaping the transcriptosomes of natural and induced regulatory T cells was analyzed using mice expressing a mutant FOXP3-EGFP fusion protein (Foxp3deltaEGFP). We used gene expression microarrays to examine the transcriptional programs of natural and induced regulatory T cells and the function of Foxp3 in organizing the transcriptosomes of the respective cell type Experiment Overall Design: Conventional T cells and natural and induced regulatory T cells were derived from Foxp3/EGFP bicistronic mice and analyzed for their gene expression profile. Conventional T cells, regulatory T cell precursors (CD4+Foxp3deltaEGFP+) and induced regulatory T cell precursors (CD4+Foxp3deltaEGFP+) cells were deriv ed from Foxp3deltaEGFP mice
Project description:Hepatitis B virus (HBV) is a hepatotropic virus that can regulate many host cellular gene expressions participating in the HBV life cycle, liver inflammation and hepatocellular injury. However, the underlying mechanism of differential gene expression is not understood. We report here a genome-wide analysis of histone methylation on two histone H3 lysine residues (H3K4me3 and H3K27me3) and gene expression profiles in HepG2 and HepG2.2.15 cells. We found that specific correlation exists between gene expression and the amounts of H3K4me3 (positive correlation) and H3K27me3 (negative correlation) across the gene body. These correlations displayed three distinct modes (repressive, active and poised), reflecting different functions of these genes in the HBV life cycle, liver inflammation and hepatocellular injury. Furthermore, a permissive chromatin state of each gene was established by a combination of different histone modifications. Our findings reveal a complex regulation by histone methylation in differential gene expression and suggest that histone methylation may be responsible for the HBV life cycle, liver inflammation and hepatocellular injury induced by HBV. Examination of 2 different histone modifications (H3K4me3, H3K27me3) in 2 cell types (HepG2, HepG2.2.15).
Project description:In this study, we determined the signature of CD4+Foxp3- effector T cells and CD4+Foxp3+ Treg cells in naive animals and following LCMV WE infection. In addition, transcriptional signatures were determined in CXCR3+ CD4+Foxp3+ Treg cells arising in Th1 settings following LCMV infection.
Project description:Epigenetic changes are crucial for the generation of immunological memory1-4. Failure to generate or maintain these changes will result in poor memory responses. Similarly, augmenting or stabilizing the correct epigenetic states offers a potential method of enhancing immune memory. Yet the transcription factors that regulate these processes are poorly defined, as are the chromatin modifying complexes they recruit and the chromatin modifications they control. Using pathogen infection models and three different mouse models, including a new conditional allele, we find that the widely expressed transcription factor Oct15, and its cofactor OCA-B6,7, are selectively required the in vivo generation of functional CD4 memory. In vitro, both proteins are also required to maintain a poised state at the Il2 target locus in resting but previously stimulated CD4 T cells, and to generate robust Il2 expression upon restimulation. OCA-B is also required for the robust re-expression of other known targets including Il17a, and Ifng. We identify an underlying mechanism involving OCA-B recruitment of the histone lysine demethylase Jmjd1a8 to targets such as Il2 and Ifng. The findings pinpoint Oct1 and OCA-B as unanticipated mediators of CD4 T cell memory. Examination of 4 different conditions in 2 genotypes
Project description:CD4+Foxp3+ Treg cells are essential for maintaining self-tolerance and preventing excessive immune responses. In the context of Th1 immune responses, co-expression of the Th1 transcription factor T-bet with Foxp3 is essential for Treg cells to control Th1 responses. T-bet-dependent expression of CXCR3 directs Tregs to the site of inflammation, however, the suppressive mediators enabling effective control of Th1 responses at this site are unknown. In this study, we determined the signature of CXCR3+ Treg cells arising in Th1 settings and defined universal features of Treg cells in this context using multiple Th1-dominated models. Our analysis defined a set of Th1-specific co-inhibitory receptors that are specifically expressed in Treg cells during Th1 immune responses. Among these, we identified the novel co-inhibitory receptor CD85k as a functional mediator of the enhanced suppression of Th1 effector cells by CXCR3+ Treg cells.
Project description:This project focuses on examining the differences in the global CD4+ T cell proteome between cells lacking the negative regulators of eIF4E( eIf4E-Binding Proteins 1/2) and WT naive CD4+ T cells both prior and following TCR stimulation.
Project description:Epigenetic changes are crucial for the generation of immunological memory. Failure to generate or maintain these changes will result in poor memory responses. Similarly, augmenting or stabilizing the correct epigenetic states offers a potential method of enhancing immune memory. Yet the transcription factors that regulate these processes are poorly defined, as are the target genes they control and they chromatin-modifying complexes they recruit. Using model pathogens and three different mouse models, we find that the widely expressed transcription factor Oct1 and its cofactor OCA-B are selectively required for the in vivo generation of functional CD4 memory. In vitro, both proteins are required to maintain a poised state at the Il2 target locus in resting but previously stimulated CD4 T cells, and to generate robust Il2 expression upon restimulation. Gene expression profiling indicates that OCA-B is also required for the robust re-expression of multiple other targets including Ifng and Il17a. ChIPseq identify multiple differentially expressed direct targets. We identify an underlying mechanism involving OCA-B recruitment of the histone lysine demethylase Jmjd1a to targets such as Il2 and Ifng. The findings pinpoint Oct1 and OCA-B as unanticipated mediators of CD4 T cell memory. Examination of transcription factor occupancy in CD4 T cells upon rest and restimulation.