Acute 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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Prothrombin (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 partView Samples
Current 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, SubjectView Samples
Target 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, TimeView Samples
We show that NRF2 activation drives hepatocellular carcinoma development in vivo. Moreover, NRF2 undergoes glucose dependent modification called glycation and requires the de-glycating enzyme FN3K to maintain NRF2' oncogenic functions. Overall design: Gene expression analysis in MYC-driven murine HCC with and without NRF2 activation. NRF2 is activated by targeting its negative regulators Keap1 or Cul3 or targeting NRF2 ETGE motif by sgRNA/Cas9 editing.
The Oncogenic Action of NRF2 Depends on De-glycation by Fructosamine-3-Kinase.
Specimen part, Disease, Disease stage, SubjectView Samples
MicroRNAs (miRNAs) have emerged as novel cancer genes. In particular, the 17~92 cluster of miRNAs is highly expressed in haematopoietic cancers and promotes lymphomagenesis in vivo1,2. Clinical use of these findings hinges on isolating the oncogenic activity within the 17~92 cluster and defining its relevant target genes. Here we show that miR-19 is sufficient to promote leukaemogenesis in Notch1 induced T-cell lymphoblastic leukaemia (T-ALL) in vivo. Consistent with the pathogenic importance of this interaction, we report a novel translocation targeting the 17~92 miRNA cluster coinciding with a second rearrangement that activates Notch1 in T-ALL. To identify the miR-19 targets responsible for its oncogenic action, we conducted a large-scale short-hairpin RNA (shRNA) screen for genes whose knockdown could phenocopy miR-19. Strikingly, the results of this screen were enriched for miR-19 target genes, and included Bim (Bcl2L11)1,3, AMP-activated kinase (Prkaa1), and the tumour suppressor phosphatases Pten and PP2A (Ppp2r5e). Hence, an unbiased, functional genomics approach reveals a coordinate clamp down on several regulators of PI3K-related survival signals by the leukaemogenic miR-19.
Genome-wide RNA-mediated interference screen identifies miR-19 targets in Notch-induced T-cell acute lymphoblastic leukaemia.
Cell lineView Samples
Background – 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, SubjectView Samples
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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Human 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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