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. Overall design: mRNA profiles of in-vitro-expanded FOXP3+ Treg and FOXP3-losing Treg cells generated by deep sequencing.
Histone methylation mediates plasticity of human FOXP3(+) regulatory T cells by modulating signature gene expressions.
Specimen part, Subject
View SamplesHepatitis 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. Overall design: A large-scale analysis of gene expression of 2 different cell types (HepG2, HepG2.2.15) using a digital gene expression (DGE) tag profiling approach.
Telbivudine treatment corrects HBV-induced epigenetic alterations in liver cells of patients with chronic hepatitis B.
Specimen part, Cell line, Subject
View SamplesUnderstanding how regulatory sequences interact in the context of chromosomal architecture is a central challenge in biology. Chromosome conformation capture revealed that mammalian chromosomes possess a rich hierarchy of structural layers, from multi-megabase compartments to sub-megabase topologically associating domains (TADs), and further down to sub-TAD loop domains. TADs appear to act as regulatory microenvironments by constraining and segregating regulatory interactions across discrete chromosomal regions. However, it is unclear whether other (or all) folding layers share similar properties, or rather TADs constitute a privileged folding scale with maximal impact on the organization of regulatory interactions. Here we present a novel parameter-free algorithm (CaTCH) that identifies hierarchical trees of chromosomal domains in Hi-C maps, stratified through their reciprocal physical insulation which is a simple and biologically relevant property. By applying CaTCH to published Hi-C datasets, we show that previously reported folding layers appear at different insulation levels. We demonstrate that although no structurally privileged folding level exists, TADs emerge as a functionally privileged scale defined by maximal enrichment of CTCF at boundaries, and maximal cell-type conservation. By measuring transcriptional output in embryonic stem cells and neural precursor cells, we show that TADs also maximize the likelihood that genes in a domain are co-regulated during differentiation. Finally, we observe that regulatory sequences occur at genomic locations corresponding to optimized mutual interactions at the scale of TADs. Our analysis thus suggests that the architectural functionality of TADs arises from the interplay between their ability to partition interactions and the genomic position of regulatory sequences. Overall design: The hybrid mouse ESC line F1-21.6 (129Sv-Cast/EiJ), previously described in (Jonkers et al., 2009), were grown on mitomycin C-inactivated MEFs in ES cell media containing 15% FBS (Gibco), 10-4 M b-mercaptoethanol (Sigma), and 1000U/ml of leukaemia inhibitory factor (LIF, Chemicon). Mouse ES cells were differentiated into neural progenitor cells (NPC) as previously described (Conti et al., 2005; Splinter et al., 2011). Total RNAs were prepared by Trizol extraction from the mouse ESC line, and for one NPC clone derived from it. Two biological replicates were collected for ESCs and NPCs. After ribosomal RNA depletion with Ribo-Zero (Illumina), RNA-seq libraries were prepared using ScriptSeq v2 kit (Illumina) following the manufacturer’s instructions. Libraries were prepared in two technical replicates per biological replicate. 50 bp single-end sequencing was performed on Illumina HiSeq 2000 instruments according to manufacturer’s instructions.
Reciprocal insulation analysis of Hi-C data shows that TADs represent a functionally but not structurally privileged scale in the hierarchical folding of chromosomes.
Specimen part, Subject
View SamplesSequencing of the 3' end of poly(A)+ RNA identifies cleavage and polyadenylation sites (pAs) and measures transcript expression. We previously developed a method, 3' region extraction and deep sequencing (3'READS), to address mispriming issues that often plague 3' end sequencing. Here we report a new version, named 3'READS+, which has vastly improved accuracy and sensitivity. Using a special locked nucleic acid oligo to capture poly(A)+ RNA and to remove bulk of the poly(A) tail, 3'READS+ generates RNA fragments with an optimal number of terminal As that balance data quality and detection of genuine pAs. With improved RNA ligation steps for efficiency, the method shows much higher sensitivity (over two orders of magnitude) compared to the previous version. Using 3'READS+, we have uncovered a sizable fraction of previously overlooked pAs located next to or within a stretch of adenylate residues in human genes, and more accurately assessed the frequency of alternative cleavage and polyadenylation (APA) in HeLa cells (~50%). 3'READS+ will be a useful tool to accurately study APA and to analyze gene expression by 3' end counting, especially when the amount of input total RNA is limited. Overall design: Nine 3''READS+ libraries were made with different amounts (100 ng, 200 ng, 400 ng, 1000 ng, 5000 ng, 15000 ng) of input Hela RNA.
3'READS+, a sensitive and accurate method for 3' end sequencing of polyadenylated RNA.
Cell line, Subject
View SamplesIn the current study, we performed transcriptome profiling of the mouse PFC to determine the dynamic changes in the Prefrontal cortex (PFC)after repeated cocaine treatment. In the current study, we observed dynamic changes in the transcriptome profiling of the PFC of repeated-cocaine treated mice, and found that distinct pathways were involved in the acute, sub-acute, and chronic stages of cocaine withdrawal. The main findings of our results include: 1) energy metabolism and protein metabolism pathways showed gradual or fluctuant decrease after cocaine withdrawal; 2) ERK pathway showed persistent changes after cocaine withdrawal; 3) plasticity related pathways, such as long-term potentiation, the regulation of the actin cytoskeleton, and the axon guidance pathway, showed a fluctuant increase after cocaine withdrawal. Our results suggest that maladaptive neural plasticity associated with psychostimulant dependence may be an ongoing degenerative process with dynamic changes in the gene network at different stages of withdrawal. Overall design: The bilateral PFC was excised from each animal at either 2 h, 24 h, or 7 days after the final injection of cocaine. To account for inter-animal variations, we obtained 2 biological replicates for each treatment group, with each replicate representing the PFCs pooled from 5 animals. Pair-end 75-nt sequencing was performed using the Illumina HiSeq2000.
Dynamic Expression Changes in the Transcriptome of the Prefrontal Cortex after Repeated Exposure to Cocaine in Mice.
Age, Specimen part, Cell line, Treatment, Subject
View SamplesCells adapt to environmental changes, including fluctuations in oxygen levels, through the induction of specific gene expression programs. To identify genes regulated by hypoxia at the transcriptional level, we pulse-labeled HUVEC cells with 4-thiouridine and sequenced nascent transcripts. Then, we searched genome-wide binding profiles from the ENCODE project for factors that correlated with changes in transcription and identified binding of several components of the Sin3A co-repressor complex, including SIN3A, SAP30 and HDAC1/2, proximal to genes repressed by hypoxia. SIN3A interference revealed that it participates in the downregulation of 75% of the hypoxia-repressed genes in endothelial cells. Unexpectedly, it also blunted the induction of 47% of the upregulated genes, suggesting a role for this corepressor in gene induction. In agreement, ChIP-seq experiments showed that SIN3A preferentially localizes to the promoter region of actively transcribed genes and that SIN3A signal was enriched in hypoxia-repressed genes, prior exposure to the stimulus. Importantly, SINA3 occupancy was not altered by hypoxia in spite of changes in H3K27ac signal. In summary, our results reveal a prominent role for SIN3A in the transcriptional response to hypoxia and suggest a model where modulation of the associated histone deacetylase activity, rather than its recruitment, determines the transcriptional output. Overall design: Exponentially growing non-synchronized HUVEC were exposed to normoxia or hypoxia (21% or 1% oxygen respectively) for 8 hours and pulse-labelled with 4-thiouridine during the last two hours of treatment. RNA was extracted from samples in each condition (total RNA) and an aliquot was subjected to affinity chromatography to purify the 4-thiouridine-labelled (newly transcribed RNA, Newly Tr) and non-labelled (Pre-existent) RNA fractions. All three RNA fractions (total, newly transcribed and pre-existent) from each sample were analyzed by high-throughput sequencing. Submission includes 12 samples corresponding to 3 independent biological replicates.
The SIN3A histone deacetylase complex is required for a complete transcriptional response to hypoxia.
Cell line, Treatment, Subject
View SamplesCells adapt to environmental changes, including fluctuations in oxygen levels, through the induction of specific gene expression programs. To identify genes regulated by hypoxia at the transcriptional level, we pulse-labeled HUVEC cells with 4-thiouridine and sequenced nascent transcripts. Then, we searched genome-wide binding profiles from the ENCODE project for factors that correlated with changes in transcription and identified binding of several components of the Sin3A co-repressor complex, including SIN3A, SAP30 and HDAC1/2, proximal to genes repressed by hypoxia. SIN3A interference revealed that it participates in the downregulation of 75% of the hypoxia-repressed genes in endothelial cells. Unexpectedly, it also blunted the induction of 47% of the upregulated genes, suggesting a role for this corepressor in gene induction. In agreement, ChIP-seq experiments showed that SIN3A preferentially localizes to the promoter region of actively transcribed genes and that SIN3A signal was enriched in hypoxia-repressed genes, prior exposure to the stimulus. Importantly, SINA3 occupancy was not altered by hypoxia in spite of changes in H3K27ac signal. In summary, our results reveal a prominent role for SIN3A in the transcriptional response to hypoxia and suggest a model where modulation of the associated histone deacetylase activity, rather than its recruitment, determines the transcriptional output. Overall design: Exponentially growing non-synchronized HUVEC were transduced with lentiviral particles encoding for shRNA targeting EPAS1 or control shRNA. 72h after infection, cells were exposed to normoxia or hypoxia (21% or 1% oxygen respectively) for 8 hours and pulse-labelled with 4-thiouridine during the last two hours of treatment. RNA was extracted from samples in each condition (total RNA) and an aliquot subjected to affinity chromatography to purify the 4-thiouridine-labelled RNA fraction (newly transcribed RNA, Newly Tr). Both RNA fractions from each condition were analyzed by high-throughput sequencing. Data includes 8 samples from a single biological replicate.
The SIN3A histone deacetylase complex is required for a complete transcriptional response to hypoxia.
Cell line, Subject
View SamplesHeterosis has long been exploited for crop breeding; however, the genetic mechanisms, particularly the initial establishment of heterosis during the early vegetative growth phase, remain elusive. The biggest challenge for that is to exclude noise genes from the identified heterosis-related candidates. Herein, we use nutrient-deficient hybrid with no measurable growth heterosis as control to filter potential background noise differentially expressed genes
Dissimilar Manifestation of Heterosis in Superhybrid Rice at Early-Tillering Stage under Nutrient-Deficient and Nutrient-Sufficient Condition.
Specimen part, Treatment
View SamplesWe found that primary root (PR) is more resistant to salt stress compared with crown roots (CR) and seminal roots (SR). To understand better salt stress responses in maize roots, six RNA libraries were generated and sequenced from primary root (PR), primary roots under salt stress (PR-salt) , seminal roots (SR), seminal roots under salt stress (SR-salt), crown roots (CR), and crown roots under salt stress (CR-salt). Through integrative analysis, we identified 444 genes regulated by salt stress in maize roots, and found that the expression patterns of some genes and enzymes involved in important pathway under salt stress, such as reactive oxygen species scavenging, plant hormone signal perception and transduction, and compatible solutes synthesis differed dramatically in different maize roots. 16 of differentially expressed genes were selected for further validation with quantitative real time RT-PCR (qRT-PCR).We demonstrate that the expression patterns of differentially expressed genes are highly diversified in different maize roots. The differentially expressed genes are correlated with the differential growth responses to salt stress in maize roots. Our studies provide deeper insight into the molecular mechanisms about the differential growth responses of different root types in response to environmental stimuli in planta. Overall design: Examination of three root types of maize under salt treatment for understanding the different responding mechenism to salt stress.
Comparative transcriptome profiling of the maize primary, crown and seminal root in response to salinity stress.
Specimen part, Subject
View SamplesThe mesenteric lymph nodes represent the immune response to eggs in schistosome infections,and the analysis of gene expression profiles of the mesenteric lymph nodes from the Vac-Cha (vaccinated with UV attenuated cercariae and challenged with normal cercariae)and Inf-Con (infected with normal cercariae) groups.
Immune events associated with high level protection against Schistosoma japonicum infection in pigs immunized with UV-attenuated cercariae.
Sex, Specimen part, Treatment
View Samples