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.
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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.
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Epithelial-mesenchymal transition (EMT) and mesenchymal-epithelial transition (MET) facilitate breast cancer (BC) metastasis, however stable molecular changes that result as a consequence of these processes remain poorly defined. Therefore, we sought to identify molecular markers that could distinguish tumor cells that had completed the EMT:MET cycle in the hopes of identifying and targeting unique aspects of metastatic tumor outgrowth.Therefore, normal murine mammary gland (NMumG) cells transformed by overexpression of EGFR (NME) cells were cultured in the presence of TGF-beta1 (5 ng/ml) for 4 weeks, at which point TGF-beta1 supplementation was discontinued and the cells were allowed to recover for an additional 4 weeks (Post-TGF-Rec). Total RNA was prepared from unstimulated cells (Pre-TGF) of similar passage and compared by microarray analysis.
Fibroblast growth factor receptor splice variants are stable markers of oncogenic transforming growth factor β1 signaling in metastatic breast cancers.
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Human NK cells were sorted into CD56dim and CD56bright NK cell subpopulations. In order to define characteristics of both populations gene profiling was performed using Affymetrix arrays U133a and U133B.
Gene and protein characteristics reflect functional diversity of CD56dim and CD56bright NK cells.
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Development of systems allowing the maintenance of native properties of mesenchymal stromal cells (MSC) is a critical challenge for studying physiological functions of skeletal progenitors, as well as towards cellular therapy and regenerative medicine applications. Conventional stem cell culture in monolayer on plastic dishes (2D) is associated with progressive loss of functionality, likely due to the absence of a biomimetic microenvironment and the selection of adherent populations. Here we demonstrate that 2D MSC expansion can be entirely bypassed by culturing freshly isolated bone marrow cells within the pores of 3D scaffolds in a perfusion-based bioreactor system, followed by enzymatic digestion for cell retrieval. The 3D-perfusion system supported MSC growth while maintaining cells of the hematopoietic lineage, and thus generated a cellular environment mimicking some features of the bone marrow stroma. As compared to 2D-expansion, sorted CD45- cells derived from 3D-perfusion culture after the same time (3 weeks) or a similar extent of proliferation (7-8 doublings) maintained a 4.3-fold higher clonogenicity and exhibited a superior differentiation capacity towards all typical mesenchymal lineages, with similar immunomodulatory function in vitro. Transcriptomic analysis performed on MSC from 5 donors validated the robustness of the process and indicated a reduced inter-donor variability as well as a significant upregulation of multipotency-related gene clusters following 3D-perfusion as compared to 2D expansion. The described system offers a model to study how factors of a 3D engineered niche may regulate MSC function and, by streamlining conventional labor-intensive processes, is prone to automation and scalability within closed bioreactor systems.
Expansion of human mesenchymal stromal cells from fresh bone marrow in a 3D scaffold-based system under direct perfusion.
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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.
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The division rate of hematopoietic stem cells (HSCs) are promoted by estradiol. To identify the mechanism by which estradiol regulates HSCs, we performed gene expresssion profiling of HSCs isolated from mice of both sexes treated with either control vehicle (oil) or estradiol for one week.
Oestrogen increases haematopoietic stem-cell self-renewal in females and during pregnancy.
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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.
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