Preterm infants are susceptible to neonatal inflammatory/infective diseases requiring drug therapy. The present study hypothesized that mRNA expression in the blood may be modulated by signaling pathways during treatment. The current study aimed to explore changes in global gene expression in the blood from preterm infants with the objective of identifying patterns or pathways of potential relevance to drug therapy. The infants involved were selected based on maternal criteria indicating increased risk for therapeutic intervention. Global mRNA expression was measured in 107 longitudinal whole blood samples using Affymetrix Human Genome U133 Plus 2.0 arrays; samples were obtained from 20 preterm infants. Unsupervised clustering revealed a distinct homogeneous gene expression pattern in 13 samples derived from seven infants undergoing continuous oxygen therapy. At these sampling times, all but one of the seven infants exhibited severe drops in peripheral capillary saturation levels below 60%. The infants were reoxygenated with 100% inspired oxygen concentration. The other samples (n=94) represented the infants from the cohort at time points when they did not undergo continuous oxygen therapy. Comparing these two sets of samples identified a distinct gene expression pattern of 5,986 significantly differentially expressed genes, of which 5,167 genes exhibited reduced expression levels during transient hypoxia. This expression pattern was reversed when the infants became stable, i.e., when they were not continuously oxygenated and had no events of hypoxia. To identify signaling pathways involved in gene regulation, the Database for Annotation, Visualization and Integrated Discovery online tool was used. Mitogen activated protein kinases, which are normally induced by oxidative stress, exhibited reduced gene expression during hypoxia. In addition, nuclear factor erythroid 2 related factor 2 antioxidant response element target genes involved in oxidative stress protection were also expressed at lower levels, suggesting reduced transcription of this pathway. The findings of the present study suggest that oxidative stress dependent signaling is reduced during hypoxia. Understanding the molecular response in preterm infants during continuous oxygenation may aid in refining therapeutic strategies for oxygen therapy.
Gene expression profiles in preterm infants on continuous long‑term oxygen therapy suggest reduced oxidative stress‑dependent signaling during hypoxia.
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View SamplesA prospective study was conducted in the Neonatal Intensive Care Unit of the University Children's hospital between September 1, 2008 and November 30, 2010. The entry criteria were (1) preterm birth below 32 weeks gestational age, (2) birthweight<1500g (VLBW). During the follow-up period, bronchopulmonary dysplasia (BPD) was diagnosed in 68 (61%) infants, including 40 (36%) children with mild disease, 13 (12%) with moderate and 15 (13%) with severe BPD. Forty-three babies served as a control group (no BPD).
Gene expression profiling in preterm infants: new aspects of bronchopulmonary dysplasia development.
Sex, Specimen part
View SamplesPerinatal asphyxia is detrimental to the newborn baby and the use of supplemental oxygen during resuscitation may worsen the prognosis of these babies. The mechanism behind hyperoxic injury is not fully understood and our aim was to investigate four oxygen therapies following hypoxia and these effects on transcriptional activity.
Transcriptome profiling of the newborn mouse brain after hypoxia-reoxygenation: hyperoxic reoxygenation induces inflammatory and energy failure responsive genes.
Specimen part
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Androgen Receptor Deregulation Drives Bromodomain-Mediated Chromatin Alterations in Prostate Cancer.
Specimen part, Cell line, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks.
Cell line, Time
View SamplesAltered patterns of transcription factor (TF) binding are now accepted as a hallmark of many aggressive cancers including prostate and breast cancers1,2. This implies that underlying global changes in chromatin accessibility may drive cancer progression, as previously hypothesized3-5. In addition there are epigenetic readers such as bromodomain containing protein 4 (BRD4), which have been shown to associate with these TFs6-8 and also to contribute to aggressive cancers of many types8,9 including prostate cancer (PC)6,10. Here we show for the first time that formaldehyde-assisted isolation of regulatory elements followed by sequencing (FAIRE-seq) applied to human prostate tumors tissue can define castrate-resistant prostate cancer (CRPC) and can be used to inform the discovery of gene-level classifiers for therapy. In addition, we show that the androgen receptor (AR) overexpression alone is a primary driver for chromatin relaxation and that this effect can be reversed using bromodomain inhibitors. We also report that bromodomain-containing proteins (BRDs) are overexpressed in advanced CRPCs and that ATAD2 and BRD2 have prognostic value. In conclusion, this is the first study demonstrating a major impact of BRDs on chromatin accessibility in CRPC in patient samples. Consequently, targeting bromodomains provides a compelling rational for combination therapy in which BRD-mediated TF binding is enhanced or modified as cancer progresses.
Androgen Receptor Deregulation Drives Bromodomain-Mediated Chromatin Alterations in Prostate Cancer.
Time
View SamplesProstate cancer is the most common non-cutaneous cancer in men. The androgen receptor (AR) a ligand-activated transcription factor, constitutes the main drug target for advanced cases of the disease. However, a variety of other transcription factors and signalling networks have been shown to be altered in patients and to influence AR activity. The oncogenic transcription factor c-Myc has been studied extensively in multiple malignancies, but its impact on AR activity in prostate cancer remains elusive. In this study we assessed the impact of clinically relevant levels of c-Myc overexpression on AR activity and transcriptional output. We found that c-Myc and the AR share a substantial amount of binding sites, which exhibit enhancer-like characteristics. Interestingly, c-Myc overexpression altered global AR chromatin occupancy and antagonised a subset of androgen-induced genes. Furthermore, c-Myc overexpression modified histone marks, most notably H3K4me1 and H3K27me3. Lastly, we validated the antagonistic relationship between c-Myc and two AR target genes, KLK3 and GNMT, in patient samples.
c-Myc Antagonises the Transcriptional Activity of the Androgen Receptor in Prostate Cancer Affecting Key Gene Networks.
Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Promoter DNA methylation patterns of differentiated cells are largely programmed at the progenitor stage.
Specimen part
View Samples-myosin heavy chain promoter controlled MerCreMer expression enables conditional, cardiomyocyte specific and tamoxifen dependent gene inactivation of floxed genes. Administration of tamoxifen has been linked to development of acute and transient cardiomyopathy. The mechanism for this is unknown.
Cre-loxP DNA recombination is possible with only minimal unspecific transcriptional changes and without cardiomyopathy in Tg(alphaMHC-MerCreMer) mice.
Sex, Specimen part, Time
View SamplesThe aim of the present study was to examine potential differences in the regulation of myocardial ECM constituents, in mice that develop hypertrophy only (ABnonHF) and in mice that develop overt heart failure (ABHF) as response to pressure overload.
Differential regulation of extracellular matrix constituents in myocardial remodeling with and without heart failure following pressure overload.
Specimen part, Treatment
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