Epidemics of influenza virus are of great challenges to the public concern. The lung inflammation and injury caused by excessive inflammatory cell infiltration into the lungs and overproduction of inflammatory mediators are major consequences during influenza virus infection. Neutrophils are vital for anti-microbial defense. However, the roles of neutrophils during viral infections are less clear. Furthermore, the molecular regulation of neutrophil fate and function at the viral infected sites is largely elusive. We found that BCL6 deficiency in neutrophils, but not in monocytes nor lung macrophages, attenuated host inflammation and morbidity following influenza infection. Mechanistically, BCL6 bound to the neutrophil gene loci involved in cellular apoptosis specifically at the site of infection. As such, BCL6 disruption resulted in increased expression of apoptotic genes in neutrophils in the respiratory tract, but not in the circulation nor bone marrow. Consequently, BCL6 deficiency promoted tissue neutrophil apoptosis. Our results have revealed a previously unappreciated role of BCL6 in modulating neutrophil apoptosis at the site of infection for the regulation of host disease development following viral infection. Overall design: Neutrophils were flow sorted based on their surface expression of CD11b and Ly6G from total lung cells of MRP8-Cre Bcl6 or Bcl6 fl/fl mice at day 6 post influenza virus infection. Total RNA was isolated and RNA-seq was performed.
BCL6 modulates tissue neutrophil survival and exacerbates pulmonary inflammation following influenza virus infection.
Specimen part, Subject
View SamplesAcute lymphoblastic leukemia (ALL), the commonest childhood malignancy, is characterized by recurring gross and submicroscopic structural genetic alterations that contribute to leukemogenesis. Disordered epigenetic regulation is a hallmark of many tumors, and while analysis of DNA methylation of limited numbers of genes or ALL samples suggests epigenetic alterations may also be important, a large-scale integrative genome-wide analysis evaluating DNA methylation in ALL has not been performed. Here, we report an integrated epigenomic, transcriptional and genetic analysis of 167 childhood ALL cases, comprising B-progenitor ALL with hyperdiploidy (N=26), ETV6-RUNX1 (N=27), TCF3-PBX1 (N=9), BCR-ABL1 (N=19), rearrangement of MLL (MLLr) (N=20), rearrangement of CRLF2 (N=11, CRLF2r), deletion of ERG (N=11), miscellaneous or normal karyotype (N=14), and T-lineage ALL (N=30), including 4 MLLr cases and 7 cases with early T-cell precursor immunophenotype. Genome-wide profiling of structural DNA alterations was performed for all cases using Affymetrix 500K and SNP 6.0 arrays. Affymetrix U133A gene expression profiling data was available for 154 cases. Genome-wide methylation profiling was performed using the HELP microarray assay, which measures methylation at approximately 50,000 CpGs distributed among 22,722 Refseq promoters. Methylation data was compared to that of normal pro-B (CD34+CD19+sIg-), pre-B (CD34-CD19+sIg-) and mature B (CD34-CD19+sIg+) cells FACS-sorted from bone marrow of 6 healthy individuals. Unsupervised hierarchical clustering of the top 4043 most variable methylation probesets identified 9 B-ALL clusters with significant correlation to specific genetic lesions including ETV6-RUNX1, MLLr, BCR-ABL1, CRLF2r, TCF3-PBX1 and ERG deletion. T-ALLs and hyperdiploid B-ALLs also defined specific DNA methylation clusters. Supervised analysis including limma and ANOVA identified distinct DNA methylation signatures for each subtype. Notably, the strength of these signatures was subtype dependent, with more differentially methylated genes observed in ALL cases with genetic alterations targeting transcriptional regulators (e.g. ETV6-RUNX1 and MLLr) and fewer genes in cases with alterations deregulating cytokine receptor signaling (e.g. CRLF2r). Aberrant DNA methylation affected specific and distinct biological processes in the various leukemia subtypes implicating epigenetic regulation of these pathways in the pathogenesis of these different forms of ALL (e.g. TGFB and TNF in ERG deleted leukemias; telomere and centriole regulation in BCR-ABL1 ALL). Aberrantly methylated genes were also enriched for binding sites of known or suspected oncogenic transcription factors that might represent cooperative influences in establishing the phenotype of the various B-ALL subtypes. Most importantly, an integrated analysis of methylation and gene expression of these ALL subtypes demonstrated striking inversely correlated expression of the corresponding gene transcripts. The methylation signatures of each subtype exhibited only partial overlap with those of normal B cells, indicating that the signatures do not simply reflect stage of lymphoid maturation. In a separate approach, we discovered that 81 genes showed consistent aberrant methylation across all ALL subtypes, including the tumor suppressor PDZD2, HOXA5, HOXA6 and MSH2. Inverse correlation with expression was confirmed in 66% of these genes. These data suggest the existence of a common epigenetic pathway underlying the malignant transformation of lymphoid precursor cells. Integrative genetic and epigenetic analysis revealed hypermethylation of genes on trisomic chromosomes that do not show increased expression, suggesting that epigenetic silencing may control genes within amplified regions and explain why only selected genes are overexpressed. Finally, analysis of individual genes targeted by recurring copy number alterations in ALL revealed a subset of genes also targeted by abnormal methylation, with corresponding changes in gene expression (e.g. ERG, GAB1), suggesting that such genes are inactivated far more frequently than suggested by genetic analyses alone. Collectively, the data support a key role of epigenetic gene regulation in the pathogenesis of ALL, and point towards a scenario where genetic and epigenetic lesions cooperatively determine disease phenotype.
Integrated genetic and epigenetic analysis of childhood acute lymphoblastic leukemia.
Specimen part
View SamplesWe performed DNA methylation (HELP array) and gene expression profiling in 69 samples of diffuse large B cell lymphoma (DLBCL). First, by gene expression, two molecular subtypes of DLBCL termed as "germinal center B cell-like" (GCB) and "activated B cell-like" (ABC) DLBCL were assigned to the 69 DLBCL cases. Then, the supervised analysis using HELP data revealed strikingly different DNA promoter methylation patterns in the two molecular DLBCL subtypes. These data provide epigenetic evidence that the DLBCL subtypes are distinct diseases that utilize different oncogenic pathways.
DNA methylation signatures define molecular subtypes of diffuse large B-cell lymphoma.
Sex, Age, Specimen part
View SamplesThe scaffold attachment factors SAFB1 and SAFB2 are paralogs, which are involved in cell cycle regulation, apoptosis, differentiation, and stress response. They have been shown to function as estrogen receptor co-repressors, and there is evidence for a role in breast tumorigenesis. To identify their endogenous target genes in MCF-7 breast cancer cells, we utilized gene expression array analysis, which was set up in a two-by-four design, with vehicle and estrogen treatment, and control, SAFB1, SAFB2, and SAFB1/SAFB2 siRNA as variables. Using custom chips containing 1.5 kb upstream regulatory region, we identified 541 SAFB1/SAFB2 binding sites in promoters of known genes, with significant enrichment on chromosome 1 and 6. Gene expression analysis revealed that the majority of target genes were induced in the absence of SAFB1 or SAFB2, and less were repressed. In contrast to SAFB2, which shared most of its target genes with SAFB1, SAFB1 had many unique target genes, most of them involved in regulation of the immune system. A subsequent analysis of the estrogen treatment group revealed that twelve percent of estrogen-regulated genes were dependent on SAFB1, with the majority being estrogen-repressed genes. These were primarily genes involved in apoptosis, such as BBC3, NEDD9, and OPG. Thus, this study confirms SAFB1/SAFB2s primary role as co-repressors, and also uncovers a previously unknown role for SAFB1 in regulation of immune genes, and in estrogen-mediated repression of genes.
SAFB1 mediates repression of immune regulators and apoptotic genes in breast cancer cells.
Cell line, Treatment
View SamplesMaternal 5-HT1A-receptor (R) is required for the timely development of the hippocampus and the establishment of emotional behaviors in Swiss-Webster (SW) mice. A partial and/or complete loss of maternal 5-HT1AR results in delayed ventral dentate granule cell (v-DGC) development and subsequent anxiety-like phenotype in the wild-type offspring by a non-genetic, presumably epigenetic mechanism. Here we tested v-DGCs for genome-wide DNA methylation changes elicited by the receptor deficient maternal environment. We identified a set of hypomethylated regions in the offspring of receptor deficient mothers. A significant fraction of these maternal-differentially methylated regions (m-DMRs) mapped to strong CpG islands, sequences that are typically not methylated or if methylated, resistant to environmental-induced changes. Many m-DMRs mapped to exons and some were associated with expression changes. Their hypomethylation was due to an arrest in de novo methylation and, to a lesser extent, to demethylation during postnatal life indicating that the perturbation in methylation coincides with the developmental delay in DGC maturation in the offspring of receptor deficient mothers. Inhibiting methylation in differentiating neurons impaired their maturation further suggesting a link between de novo methylation and neuronal differentiation. These data suggest that methylation at specific exonic CpG-islands may contribute to the mechanism through which maternal 5-HT1AR modulates hippocampal development and consecutively the level of anxiety in the SW offspring. Reduced 5-HT1AR-binding has been reported in individuals, particularly in association with anxiety/depression, including peri/postpartum depression. Therefore, maternal receptor deficit may contribute, via a non-genetic mechanism, to the high prevalence and heritability of anxiety disorders in human. Overall design: Examined transcriptomes of 5HT1A wild type offspring with 5HT1A wild type/heterozygous mother or 5HT1A KO offspring with 5HT1A of heterozygous/knock out mother
Differential gene body methylation and reduced expression of cell adhesion and neurotransmitter receptor genes in adverse maternal environment.
Specimen part, Cell line, Subject
View SamplesHistone modifications and DNA methylation represent two distinct modes of varying epigenetic landscapes, but whose exact interrelationship remains unclear. Previous studies have shown that histone H3 lysine 4 trimethylation (H3K4me3) inhibits the binding of de novo DNA methyltransferases (Dnmt) through the ATRX-DNMT3-DNMTL (ADD) domain, thus protecting H3K4me3 marked CpG islands (CGI) from DNA methylation. In addition to H3K4me3, we identified antagonistic relationship between H3T3 phosphorylation and the binding of the ADD domain to the unmodified H3 N-terminus. To assess the physiological relevance of these restrictions, we engineered the wild-type ADD domain of Dnmt3a (WT) to permit additional binding to either H3K4me3 (WWD) or H3T3ph (R) and stably introduced FLAG-tagged, full-length normal or mutant Dnmt3a2 into ESCs lacking all Dnmts (TKO; triple knock-out of Dnmt1, Dnmt3a, and Dnmt3b) using the PiggyBac transposon system. For each WT-, WWD-, and R-Dnmt3a2, we generated bulk and clonally-derived ESC lines. We then employed chromatin immunoprecipitation followed by high-throughput DNA sequencing (ChIP-seq) to identify the genomic distribution of full-length WT-, WWD-, R-Dnmt3a2, and the H3K4me3 distribution. In parallel, we quantitatively measured genome-wide CpG (cytosine) methylation at base-pair resolution using an enhanced form of reduced representation bisulfite sequencing (RRBS), and performed RNA-seq to assess transcription in matched ESC lines. Overall design: Examination of mRNA profiles in Dnmt TKO-ESCs expressing wild-type/mutant Dnmt3a2.
Engineering of a Histone-Recognition Domain in Dnmt3a Alters the Epigenetic Landscape and Phenotypic Features of Mouse ESCs.
No sample metadata fields
View SamplesOur data demonstrated that Bcl6 directly binds and represses trafficking receptors S1pr1 and Grp183 by recruiting Hdac2 through the RD2 domain. Deregulation of these genes impairs B-cell migration and may contribute to the Germinal Center failure in Bcl6RD2MUT mice. Overall design: RNAseq was performed in endogenous BCL6-depleted OCI-LY1 cells rescued with either WT or RD mutant BCL6 (N=3 for each group).
The BCL6 RD2 domain governs commitment of activated B cells to form germinal centers.
No sample metadata fields
View SamplesThe EZH2 histone methyltransferase is required for B cells to form germinal centers (GCs). Here we show that EZH2 mediates GC formation through repression of cyclin-dependent kinase inhibitor CDKN1A (p21Cip1). Deletion of Cdkn1a rescued the GC reaction in Ezh2 knockout mice. To study the effects of EZH2 in primary GC B cells we generated and validated a 3D B cell follicular organoid system that mimics the endogenous GC reaction. Using this system we found that depletion of EZH2 suppressed G1 to S phase transition of GC B cells in a Cdkn1a dependent manner. GC B cells of Cdkn1a;Ezh2 double knockout mice exhibited high levels of phospho Rb, indicating that loss of Cdkn1a allows progression of cell cycle. Moreover, we show that the transcription factor E2F1 plays a major role in inducing EZH2 upregulation during the GC reaction. E2F1 deficient mice manifest impaired GC responses, which was rescued by restoring EZH2 expression, thus defining a positive feedback loop whereby EZH2 controls GC B cell proliferation by suppressing CDKN1A, allowing cell cycle progression with a concomitant phosphorylation of Rb and release of E2F1. Overall design: gene expression profiles of murine B cells
EZH2 enables germinal centre formation through epigenetic silencing of CDKN1A and an Rb-E2F1 feedback loop.
Specimen part, Disease, Cell line, Subject, Time
View SamplesAcute Myeloid Leukemia (AML) is a heterogeneous disease from the molecular and biological standpoints, and even patients with a specific gene expression profile may present clinical and molecular heterogeneity. We studied the epigenetic profiles of a cohort of patients that shared a common gene expression profile but differed in that only half of them harbored mutations of the CEBPA locus, while the rest presented with silencing of this gene and co-expression of certain T cell markers. DNA methylation studies revealed that these two groups of patients could be readily segregated in an unsupervised fashion based on their DNA methylation profiles alone. Furthermore, CEBPA silencing was associated with the presence of an aberrant DNA hypermethylation signature, which was not present in the CEBPA mutant group. This aberrant hypermethylation occurred more frequently at sites within CpG islands. CEBPA silenced leukemias also displayed marked hypermethylation when compared with normal CD34+ hematopoietic cells, while CEBPA mutant cases showed only mild changes in DNA methylation when compared to these normal progenitors. Biologically, CEBPA silenced leukemias presented with a decreased response to myeloid growth factors in vitro.
Genome-wide epigenetic analysis delineates a biologically distinct immature acute leukemia with myeloid/T-lymphoid features.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
H2.0-like homeobox regulates early hematopoiesis and promotes acute myeloid leukemia.
Specimen part, Cell line
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