Histone 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.
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View SamplesAcute progressive feed restriction (APFR) represents a specific form of caloric restriction in which feed availability is increasingly curtailed over a period of a few days to a few weeks. It is often used for control animals in toxicological and pharmacological studies on compounds causing body weight loss to equalize weight changes between experimental and control groups and thereby, intuitively, to also set their metabolic states to the same phase. However, scientific justification for this procedure is lacking. In the present study, we analyzed by DNA microarrays the impact on hepatic gene expression in rats of two APFR regimens that caused identical diminution of body weight (19%) but differed slightly in duration (4 vs. 10 days). In addition, white adipose tissue (WAT) was also subjected to the transcriptomic analysis on day-4. The data revealed that the two regimens led to distinct patterns of differentially expressed genes in liver, albeit some major pathways of energy metabolism were similarly affected (particularly fatty acid and amino acid catabolism). The reason for the divergence appeared to be entrainment by the longer APFR protocol of peripheral oscillator genes, which resulted in derailment of circadian rhythms and consequent interaction of altered diurnal fluctuations with metabolic adjustments in gene expression activities. WAT proved to be highly unresponsive to the 4-day APFR as only 17 mRNA levels were influenced by the treatment. This study demonstrates that body weight is a poor proxy of metabolic state and that the customary protocols of feed restriction can lead to rhythm entrainment.
Genome-wide effects of acute progressive feed restriction in liver and white adipose tissue.
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View SamplesProthrombin (PT) and osteopontin (OPN) promotes adhesion of different TRAP-positive multinucleated cells isolated from rat long bone (Hu et al. Exp Cell Res. 2008; 314: 638-50). The PT-adhering cell could represent either an immature precursor to the OPN-adherent osteoclast or constitute a distinct multinucleated cell population with a unique role in bone. Herein, phenotypic differences between PT- and OPN- cells were investigated with microarray- expression analysis. Characteristic for PT-cells was expression of innate immune response genes and scavenger receptors whereas OPN-cells expressed typical osteoclast proteins such as collagenases implicated in bone degradation.
Isolation and phenotypic characterization of a multinucleated tartrate-resistant acid phosphatase-positive bone marrow macrophage.
Specimen part
View SamplesTarget specific short single-stranded DNA (ssDNA) molecules, called aptamers, are auspicious ligands for numerous in vivo applications. However, aptamers are synthetic molecules, which might be recognized by the immune cells in vivo and induce an activation of the innate immune system. Thus, immune activation potential of synthetic ssDNA oligonucleotides (ODNs) was determined using a well established closed-loop circulation model. Fresh human blood was incubated at 37C for 2 or 4 hours with ssDNA ODNs (SB_ODN) or CpG ODN as positive control. Transcriptional changes were determined by microarray analyses. Blood samples containing SB_ODN demonstrated after 4 hours a significant regulation of 295 transcripts. Amongst others, CCL8, CXCL10, CCL7 and CXCL11 were highest regulated genes. Gene Ontology terms and KEGG pathway analyses exhibited that the differentially expressed genes belong to the transcripts that are regulated during an immune and inflammatory response, and were overrepresented in TLR signaling pathway. This study shows for the first time the potential of aptamers to activate immune system after systemic application into the human blood. Thus, we highly recommend performing of these preclinical tests with potential aptamer-based therapeutics.
Potential capacity of aptamers to trigger immune activation in human blood.
Sex, Specimen part, Treatment, Subject, Time
View SamplesCurrent pharmacotherapies for symptomatic benign prostatic hyperplasia (BPH), an androgen receptor (AR) driven, inflammatory disorder affecting elderly men, include 5a-reductase (5AR) inhibitors (i.e. dutasteride and finasteride) to block the conversion of testosterone to the more potent AR ligand dihydrotestosterone (DHT). Since DHT is the precursor for estrogen receptor ß (ERß) ligands, 5AR inhibitors could potentially limit ERß activation, which maintains prostate tissue homeostasis. We have uncovered signaling pathways in BPH-derived prostate epithelial cells (BPH-1) that are impacted by 5AR inhibition. The induction of apoptosis and repression of the cell-adhesion protein E-cadherin by the 5AR inhibitor, dutasteride, requires both ERß and TGFß. Dutasteride also induces cyclooxygenase type 2 (COX-2), which functions in a negative-feedback loop in TGFß and ERß signaling pathways as evidenced by the potentiation of apoptosis induced by dutasteride or finasteride upon pharmacological inhibition or shRNA-mediated ablation of COX-2. Concurrently, COX-2 positively impacts ERß action through its effect on the expression of a number of steroidogenic enzymes in the ERß-ligand metabolic pathway. Therefore, effective combination pharmacotherapies, which have included non-steroidal anti-inflammatory drugs, must take into account biochemical pathways affected by 5AR inhibition and opposing effects of COX-2 on the tissue protective action of ERß. Overall design: Next-generation sequencing (n=3) of shRNA mediated knockdown of COX-2 or scrambled control in BPH-1 prostate epithelial cell line
Opposing Effects of Cyclooxygenase-2 (COX-2) on Estrogen Receptor β (ERβ) Response to 5α-Reductase Inhibition in Prostate Epithelial Cells.
Specimen part, Cell line, Subject
View SamplesAnalysis of genes regulated by Maf and donwstream of ErbB2 in P8 Schwann cells
Maf links Neuregulin1 signaling to cholesterol synthesis in myelinating Schwann cells.
Specimen part
View SamplesBackground – Epigenetic alterations are stable modifications to chromatin structure that occur in response to environmental cues such as hypoxia or altered nutrient delivery. DNA methylation is a well-established and dynamic DNA modification that contributes to the regulation of gene expression. In the current study, we test the hypothesize that ischemic heart failure is defined by a distinct signature of DNA methylation that corresponds with altered expression of genes involved in cardiac ventricular dysfunction. Methods and Results – Using a methylation array, we quantified genome-wide DNA methylation of endomyocardial samples acquired from patients with ischemic (n = 6) or non-ischemic (n = 5) heart failure. RNA-sequencing analysis was performed in the same samples to identify transcriptomic changes (Fold Change > 1.5, Q < 0.05, FPKM > 2) associated with differential methylation (|Percent Change| > 5%, p < 0.05). Of the promoter-associated CpG Islands, which are well-established regions of negative transcriptional regulation, we identified a signature of robust hypermethylation. The methylation changes linked to significantly decreased transcripts included key fatty acid metabolic regulators (e.g. KLF15, AGPAT9, APOA1, and MXD4). Among the few hypomethylated and induced genes was PFKFB3, which encodes for the rate-limiting enzyme of glycolysis. Gene set enrichment analysis identified TGFß as a nodal upstream regulator of the methylation changes, potentially supporting a role of DNA methylation in the increased fibrosis and apoptosis that accompanies ischemic heart failure. Conclusions – Our data identify that the DNA methylation signature recapitulates the pathologic hallmarks of ischemic heart failure. Furthermore, we show that differential DNA methylation of CpG islands within the promoter depict alterations in metabolic substrate utilization known to occur in ischemic heart failure, and may govern a return to the fetal-like metabolic program. Overall design: RNA Sequencing analysis of left ventricle samples in 11 subjects with end-stage heart failure.
Genome-wide DNA methylation encodes cardiac transcriptional reprogramming in human ischemic heart failure.
Sex, Age, Race, Subject
View SamplesHuman embryonic stem cells were differentiated into peripheral sensory neurons via the intermediate generation of neural crest like cell (NCC). Using various markers we identified these cells as LTMR. We then analyzed there complete transcriptional profile in comparison to the intermediate neural crest like cells. Overall design: mRNA expression data of human ESC-derived sensory neuron clusters (10-20 cells) and human ESC-derived neural crest like cells (~100 cells) was generated by illumina deep sequencing
PIEZO2 is required for mechanotransduction in human stem cell-derived touch receptors.
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View SamplesAML/MDS patients carrying 11q amplifications involving the mixed lineage leukemia gene (MLL) locus are characterized by a later onset, a complex aberrant karyotype (CAK) frequently including deletions within 5q, 17p and 7q, as well as fast progression of the disease with extremely poor prognosis. We and other have shown that the MLL gene is over expressed in amplified cases, however, in most of the cases the amplified region is not restricted to the MLL locus. In the present study we investigated 19 patients with AML/MDS and MLL gain/amplification [15 AML (two secondary, following MDS and PV, and three therapy related) and 4 MDS cases (two therapy related)]. By means of array CGH performed in 12 patients (GSE9928) we were able to delineate the minimal deleted regions within 5q, 17p and 7q and identified three independent regions 11q/I-III that were amplified in all cases. Gene expression profiles established in 15 cases were used to define the candidate genes within these regions. Interestingly, analysis of our data suggests an interdependency of genes influenced by losses of 5q and 17p and expression of genes present in 11q23-25. Additionally, we demonstrate that the gene expression signature can be used to discriminate AML/MDS with MLL amplification from all other types of AML, thus, indicating specific pathogenesis present in this entity.
AML/MDS with 11q/MLL amplification show characteristic gene expression signature and interplay of DNA copy number changes.
Sex, Age, Specimen part, Disease
View SamplesThis work purposed on screening candidates of key genes invovled in the production of phenylacylated flavonol-glycosides
Characterization of a recently evolved flavonol-phenylacyltransferase gene provides signatures of natural light selection in Brassicaceae.
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