Genome-wide mapping of p300 binding in resting and activated human naïve and memory CD8 T cells
ABSTRACT: Memory T cells (TM) play a prominent role in protective and auto-immunity because they mount a more effective response than naïve T cells (TN), by rapidly expressing a large number of immune response genes upon stimulation. Previous studies have shown a correlation between increased histone acetylation levels and rapid gene expression at specific loci in CD8+ TM. However, the underlying mechanisms of histone acetylation remodeling in TM and its role in regulating global gene expression are not well defined, particularly in human TM cells. In this study, we examined the global level of histone acetylation and the expression of histone acetyltransferases and deacetylases , and found no differences between human CD8+ TN and TM cells. Through Genomegenome-wide mapping of the histone acetyltransferase p300 in human CD8+ TN and TM cells, recruitment of p300 was found to be positively correlated with the expression of 213 genes in TM and 516 genes in TN cells at rest, and was positively correlated with the expression of 556 genes in TM and 330 genes in TN cells after 4 hrs’ stimulation. Importantly, genes which have positive correlations between expression levels and p300 occupancy in TM were significantly enriched in effector functions of CD8+ T cells, while those in TN cells were over-presented in nucleic acid processing and cell differentiations. At IFNG locus, specifically, the recruitment of p300 was significantly higher in CD8+ TM than TN and cells that were correlated with increased levels of histone acetylation at this locus, and robust IFN-g expression by CD8+ TM cells. Selective inhibition of p300 and deletion of p300 binding sites within the IFNG promoter resulted in decreased histone acetylation at this locus and the lower expression level of IFN-g in CD8+ TM cells. These results suggest that recruitment of the histone acetyltransferase p300 modifies histone acetylation and allows rapid expression of IFNG, and likely a large set of immune response genes, in human CD8+ TM, which in turn contribute to the enhanced functionality of human CD8+ TM cells. Overall design: Human naïve and memory T cells were isolated from peripheral blood of healthy individuals by FACS, and were triggered through CD3/CD28 signaling for 0 hr or 4 hr. Chromatin were fixed with 1% formaldehyde, fragmented by sonication, and fragments that were bound by p300 were immuno-precipitated with a p300 specific antibody. Immuno-precipitated DNA was analyzed by Illumina/Solexa ChIP-Sequencing.
Project description:Memory T cells (TM) play a prominent role in protection and auto-immunity due to their ability to mount a more effective response than naïve T cells (TN). However, the molecular mechanisms underlying enhanced functionality of TM are not well defined, particularly in human TM. We examined the global gene expression profiles of human CD8+ TN and TM before and after stimulation. There were 1,284, 1,373 and 1,629 differentially expressed genes between TN and TM at 0 hr, 4 hr and 24 hr after stimulation, respectively, with more genes expressed to higher levels in TM. Genes rapidly up-regulated in TN cells were largely involved in nitrogen, nucleoside and amino acid metabolisms. In contrast, those in CD8+ TM were significantly enriched for immune-response-associated processes, including cytokine production, lymphocyte activation and chemotaxis. Multiple cytokines were rapidly up-regulated in TM cells, including effector cytokines known to be produced by CD8+ T cells and important for their functions, as well as regulatory cytokines, both pro- and anti-inflammatory, that are not typically produced by CD8+ T cells. These results provide new insights into molecular mechanisms that contribute to the enhanced functionality of human CD8+ TM and their prominent role in protection and auto-immunity. Naïve and memory phenotype CD8 T cells were purified by FACS from healthy individuals and cultured in vitro with the stimulation of anti-CD3/CD28 mAbs for 0 hr, 4 hr and 24 hr. Total RNA was purified from un-stimulated and stimulated naive and memory CD8 T cells and hybridized to individual single-color arrays.The purification and stimulation protocol was performed two independent times.
Project description:Enhancer activation is a critical step for gene activation. Here we report a novel epigenetic crosstalk at enhancers between the UTX (H3K27 demethylase)-MLL4 (H3K4 methyltransferase) complex and the histone acetyltransferase p300. We demonstrate that UTX, in a demethylase activity-independent manner, facilitates conversion of naïve (unmarked) enhancers in embryonic stem cells to an active (H3K4me1+/H3K27ac+) state by recruiting and coupling the enzymatic functions of MLL4 and p300. Loss of UTX leads to attenuated enhancer activity, characterized by reduced levels of H3K4me1 and H3K27ac as well as impaired transcription. The UTX-MLL4 complex enhances p300-dependent H3K27 acetylation through UTX-dependent stimulation of p300 recruitment while MLL4-mediated H3K4 monomethylation, reciprocally, requires p300 function. Importantly, MLL4-generated H3K4me1 further enhances p300-dependent transcription. This work reveals a previously unrecognized cooperativity among enhancer-associated chromatin modulators, including a unique function for UTX, in establishing an “active enhancer landscape” and defines a mechanism for the joint deposition of H3K4me1 and H3K27ac. Overall design: RNA-sequencing of mouse ES cells.
Project description:Enhancer activation is a critical step for gene activation. Here we report a novel epigenetic crosstalk at enhancers between the UTX (H3K27 demethylase)-MLL4 (H3K4 methyltransferase) complex and the histone acetyltransferase p300. We demonstrate that UTX, in a demethylase activity-independent manner, facilitates conversion of naïve (unmarked) enhancers in embryonic stem cells to an active (H3K4me1+/H3K27ac+) state by recruiting and coupling the enzymatic functions of MLL4 and p300. Loss of UTX leads to attenuated enhancer activity, characterized by reduced levels of H3K4me1 and H3K27ac as well as impaired transcription. The UTX-MLL4 complex enhances p300-dependent H3K27 acetylation through UTX-dependent stimulation of p300 recruitment while MLL4-mediated H3K4 monomethylation, reciprocally, requires p300 function. Importantly, MLL4-generated H3K4me1 further enhances p300-dependent transcription. This work reveals a previously unrecognized cooperativity among enhancer-associated chromatin modulators, including a unique function for UTX, in establishing an “active enhancer landscape” and defines a mechanism for the joint deposition of H3K4me1 and H3K27ac. Overall design: ChIP-sequencing of mouse ES cells.
Project description:The acetyltransferases CBP and p300 are multifunctional transcriptional co-activators; however, their acetylation targets, site-specific acetylation kinetics, and function in proteome regulation are incompletely understood. We combined quantitative proteomics with novel CBP/p300-specific catalytic inhibitors, bromodomain inhibitor, and gene knockout to show that CBP/p300 acetylates thousands of sites, including signature histone sites, as well as a multitude of sites on signaling effectors and enhancer-associated transcriptional regulators. Kinetic analysis identified a subset of CBP/p300-regulated sites with very rapid (<30min) acetylation turnover, revealing a dynamic balance between acetylation and deacetylation. Quantification of acetylation, mRNA, and protein abundance after CBP/p300 inhibition reveals a kinetically competent network of gene expression that strictly depends on CBP/p300-catalyzed rapid acetylation. Collectively, our in-depth acetylome analyses reveal systems attributes of CBP/p300 targets, and the resource dataset provides a framework for investigating CBP/p300 functions, as well as for understanding the impact of small molecule inhibitors targeting its catalytic and bromodomain activities.
Project description:NUT, nuclear protein in testis is the universal fusion partner of BRD4 in the highly aggressive NUT Midline Carcinoma (NMC), but its physiological function was unknown. Here we show that Nut is exclusively expressed in post-meiotic spermatogenic cells, at the time of genome-wide histone hyperacetylation. Inactivation of Nut induces a spermatogenesis arrest at the histone-to-protamine replacement stage, leading to male infertility. Subsequent molecular investigations show that Nut sustains global histone H4 hyperacetylation in post-meiotic cells. Additionally, Nut mediates a p300/CBP-dependent gene expression program and, by enhancing acetylation of H4 at both K5 and K8 sites, provides binding sites for the first bromodomain of Brdt, which drives histone removal. Nut’s major function is therefore to use the ubiquitous HATs p300/CBP to direct a cell-type specific histone hyperacetylation. Its ectopic activity in NMC recreates a forced p300-induced histone hyperacetylation / bromodomain binding loop that normally operates in post-meiotic spermatogenic cells.
Project description:Ectopic expression of the double homeodomain transcription factor DUX4 causes facioscapulohumeral muscular dystrophy (FSHD). Mechanisms of action of DUX4 are currently unknown. Using immortalized human myoblasts with a titratable DUX4 transgene, we identify by mass spectrometry an interaction between the DUX4 C-terminus and the histone acetyltransferases p300/CBP. Chromatin immunoprecipitation shows that DUX4 recruits p300 to its target gene, ZSCAN4, displaces histone H3 from the center of its binding site, and induces H3K27Ac in its vicinity, but C-terminal deleted DUX4 does not. We show that a DUX4 minigene, bearing only the homeodomains and C-terminus, is transcriptionally functional and cytotoxic, and that overexpression of a nuclear targeted C-terminus impairs the ability of WT DUX4 to interact with p300 and to regulate target genes. Genomic profiling of DUX4, histone H3, and H3 modifications reveals that DUX4 binds two classes of locus: DNase accessible H3K27Ac-rich chromatin and inaccessible H3K27Ac-depleted MaLR-enriched chromatin. At this latter class, it acts as a pioneer factor, recruiting H3K27 acetyltransferase activity and opening the locus for transcription. In concert with local increased H3K27Ac, the strong H3K27Ac peaks at distant sites are significantly depleted of H3K27Ac, thus DUX4 uses its C-terminus to induce a global reorganization of H3K27 acetylation. Two biological samples were analyzed with 4 antibodies for ChIP-Seq and in triplicate for RNA-Seq.
Project description:Th cell differentiation is transcriptionally regulated, relying on the induction of “lineage-defining” transcription factors. We report that formation of super-enhancers is critical in robust induction of Th9 cells and that assembly of the Il9 super-enhancers requires OX40-triggered chromatin H3K27 acetylation. Mechanistically, we found that OX40 costimulation induces RelB expression, which recruits the histone acetyltransferase p300 to the Il9 locus to catalyze H3K27 acetylation. This allows binding of the super-enhancer factor Brd4 to initiate assembly of the super-enhancer complex, which in turn drives robust Th9 induction. Thus, Th9 cells are induced in massive numbers upon OX40 costimulation and disruption of super-enhancers abolished Th9 induction in vitro and inhibited Th9-mediated allergic airway inflammation in vivo. Our data identify super-enhancers as a key mechanism of Th9 induction and uncover a new mechanism of Th cell differentiation. Overall design: Analysis of H3K27Ac histone modifications and BRD4 binding in CD4+ T cells cultured in vitro under Th9 differentiation conditions for 48 hours in the presence or absence of OX40 ligation.
Project description:Many questions remain about how close association of genes and distant enhancers occurs and how this is linked to transcription activation. In erythroid cells, LDB1 is recruited to the β-globin locus via LMO2 and is required for looping of the β-globin locus control region (LCR) to the active β-globin promoter. We show that the LDB1 dimerization domain (DD) is necessary and, when fused to LMO2 is sufficient, to completely restore LCR-promoter looping and transcription in LDB1 depleted cells. The looping function of the DD is unique and irreplaceable by heterologous dimerization domains. Dissection of the DD revealed distinct functional properties of conserved subdomains. Notably, a conserved helical region (DD4/5) is dispensable for LDB1 dimerization and chromatin looping but essential for transcriptional activation. DD4/5 is required for the recruitment of the co-regulators FOG1 and NuRD complex. Lack of DD4/5 alters histone acetylation and RNA polymerase II recruitment and results in failure of the locus to migrate to the nuclear interior as normally occurs during erythroid maturation. These results uncouple enhancer-promoter looping from nuclear migration and transcription activation and reveal new roles for LDB1in these processes. RNA-seq in LDB1 knockdown, LDB1 delta4/5 construct, LDB1 full-length construct, and control in induced MEL cells; three replicates each.
Project description:Reversible acetylation of histone and nonhistone proteins plays pivotal role in cellular homeostasis. Dysfunction of histone acetyltransferases (HATs) leads to several diseases including cancer, neurodegenaration, asthma, diabetes, AIDS and cardiac hypertrophy. We describe the synthesis and characterization of a set of p300-HAT specific small molecule inhibitors from a natural nonspecific HAT inhibitor, garcinol, which is highly toxic to cells. We show that the specific inhibitor selectively represses the p300-mediated acetylation of p53 in vivo. Furthermore, inhibition of p300-HAT down regulates several genes but significantly a few important genes are also upregulated. Remarkably, these inhibitors were found to be nontoxic to T cells, inhibit histone acetylation of HIV infected cells and consequently inhibit the multiplication of HIV. Keywords: Response to Inhibition of p300-HAT Overall design: The total RNA was isolated from control and treated cells using TRIZOL (Invitrogen) method. The Micromax direct labeling kit, MPS502 (PerkinElmer) was used to synthesize the labeled cDNA from 70 ug of total RNA and further process the hybridized cDNA on the array. All the steps were carried out according to manufacturer’s instructions (www.perkinelmer.com/lifesciences). The array slides were scanned immediately by PerkinElmer Scan array Gx Microarray scanner. The Scan array software (PerkinElmer) was used for grid wise normalization of array images. Four arrays were used with at least two biological treatments of cells and dye swap experiments were included in the final analysis. The data was analysed by GeneSpring GX and Biointerpreter software from Genotypic Technology, Bangalore. The differential expression was considered if the Log 2 mean of at least -1 for the down regulated genes and +1 for the upregulated genes. We considered only the genes that were reproducible from all four replicates.
Project description:Some unicellular organisms exhibit collective decision-making through intercellular communication once a quorum of members sense an environmental stress. Whether T cells at different states of differentiation may also synchronize their behavior on a population basis through direct interactions remains unclear. We report that memory CD8+ T cells (TMem) directly interact with naive T cells (TN) during priming, affecting the phenotypic, functional, transcriptional and metabolic differentiation of TN-derived progeny. This previously unrecognized, contact and concentration-dependent interaction between naive (TN) and memory CD8+ T cells (TMem) directly enhanced TN effector differentiation through non-apoptotic Fas signaling resulting in downstream Akt pathway activation. TN primed with TMem exhibited significantly impaired persistence and antitumor activity compared with TN primed alone. Disruption of FasL-Fas signaling in TN cells limited differentiation and enhanced anti-tumor immunity while provision of exogenous FasL in the absence of TMem impaired anti-tumor immunity by augmenting TN differentiation. These findings reveal that the full therapeutic potential of TN-derived cells for adoptive immunotherapy requires physical separation from TMem prior to priming or antagonism of Fas-signaling. FACS-sorted in vitro differentiated TMem samples were without stimulation (0 hours) (n=3), and FACS-sorted in vitro differentiated TMem samples were stimulated using CD3-specific and CD28-specific antibodies and IL-2 for 18 (n=3) and 96 (n=3) hours. FACS-sorted naive Pmel-1 CD8+ T cell samples were without stimulation (0 hours) (n=3), and FACS-sorted TN-derived Pmel-1 CD8+ T cell samples were stimulated using CD3-specific and CD28-specific antibodies and IL-2 for 18 (n=3) and 96 (n=3) hours. FACS-sorted TN-derived Pmel-1 CD8+ T cell samples were stimulated in the presence of TMem using CD3-specific and CD28-specific antibodies and IL-2 for 18 (n=3) and 96 (n=3) hours. FACS-sorted in vitro differentiated TMem samples were stimulated in the presence of TN using CD3-specific and CD28-specific antibodies and IL-2 for 18 (n=3) and 96 (n=3) hours. All samples were done in triplicate as biological repeats.