Progenitor cells maintain self-renewing tissues throughout life by sustaining their capacity for proliferation while suppressing cell cycle exit and terminal differentiation. DNA methylation provides a potential epigenetic mechanism for the cellular memory needed to preserve the somatic progenitor state through repeated cell divisions. DNA methyltransferase 1 (DNMT1) maintains DNA methylation patterns after cellular replication. Although dispensable for embryonic stem cell maintenance, a clear role for DNMT1 in maintaining the progenitor state in constantly replenished somatic tissues, such as mammalian epidermis, is uncharacterized. Here we show that DNMT1 is essential for supporting epidermal progenitor cell function. DNMT1 protein was found enriched in undifferentiated cells, where it was required to retain proliferative stamina and suppress differentiation. In tissue, DNMT1 depletion led to exit from the progenitor cell compartment, premature differentiation and eventual tissue loss. These effects correlated with DNA methylation as genome-wide analysis revealed that a significant portion of epidermal differentiation gene promoters were methylated in self-renewing conditions but were subsequently demethylated during differentiation.
DNMT1 maintains progenitor function in self-renewing somatic tissue.
Sex, Specimen part
View SamplesPseudomonas aeruginosa is a re-emerging opportunistic pathogen with broad antimicrobial resistance. We have previously reported that the major siderophore pyoverdine from this pathogen disrupts mitochondrial networks and induces a lethal hypoxic response in model host Caernorhabditis elegans. However, the mechanism of such cytotoxicity remained unclear. Here, we demonstrate that pyoverdine translocates into host cells, binding to host ferric iron sources. The reduction of host iron content disrupts mitochondrial function such as NADH oxidation and ATP production and activates mitophagy. This activates a specific immune response that is distinct from colonization-based pathogensis and exposure to downstream pyoverdine effector Exotoxin A. Host response to pyoverdine resembles that of a hypoxic crisis or iron chelator treatment. Furthermore, we demonstrate that pyoverdine is a crucial virulence factor in P. aerguinosa pathogenesis against cystic fibrosis patients; F508 mutation in human CFTR increases susceptibility to pyoverdine-mediated damage.
Pyoverdine, a siderophore from Pseudomonas aeruginosa, translocates into C. elegans, removes iron, and activates a distinct host response.
Specimen part, Treatment
View SamplesThis study assessed the transcriptional profile of SiHa cells. SiHa is a cervical cancer cell line with integrated HPV16, and was used as a model to study human gene expression in the context of integrated virus. Gene expression in SiHa, calculated by Cufflinks, was scored in windows around the locations of known viral integrations in patients or cell lines to determine if there was an association between gene expression and viral integration. We found that SiHa gene expression was higher near loci of integration for HPV18 vs. HPV16, cervical tissues vs. head and neck cancers, and cervical cancers vs. in vitro integrations. This study provides insight into the factors that may influence where viruses integrate in the human genome. Overall design: Gene Expression in untreated SiHa cells.
Meta-Analysis of DNA Tumor-Viral Integration Site Selection Indicates a Role for Repeats, Gene Expression and Epigenetics.
No sample metadata fields
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (dorsolateral prefrontal cortex and orbitofrontal cortex) from patients with bipolar disorder and matched healthy controls.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (dorsolateral prefrontal cortex) from patients with bipolar disorder and matched healthy controls. A cohort of 70 subjects was investigated and the final analysis included 30 bipolar and 31 control subjects. Differences between disease and control groups were identified using a rigorous statistical analysis with correction for confounding variables and multiple testing.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesFresh frozen post mortem prefrontal cortex tissue (Brodman area 46) was obtained from 44 individuals varying in age from 0 to 49 years. RNA was extracted from these samples and hybridized to HG133plus2.0 GeneChips. The data was used to examine patterns of gene expression over the course of human postnatal developmental and ageing.
Gene expression in the prefrontal cortex during adolescence: implications for the onset of schizophrenia.
No sample metadata fields
View SamplesNTHi bacteria or saline were inoculated into the middle ears of mice. Mice were sacrificed at various times to monitor the course of infection.
The transcriptome of a complete episode of acute otitis media.
Specimen part, Treatment, Time
View SamplesBipolar affective disorder is a severe psychiatric disorder with a strong genetic component but unknown pathophysiology. We used microarray technology (Affymetrix HG-U133A GeneChips) to determine the expression of approximately 22 000 mRNA transcripts in post-mortem brain tissue (orbitofrontal cortex) from patients with bipolar disorder and matched healthy controls. Orbitofrontal cortex tissue from a cohort of 30 subjects was investigated and the final analysis included 10 bipolar and 11 control subjects. Differences between disease and control groups were identified using a rigorous statistical analysis with correction for confounding variables and multiple testing.
Gene expression analysis of bipolar disorder reveals downregulation of the ubiquitin cycle and alterations in synaptic genes.
Sex, Age, Disease
View SamplesThis SuperSeries is composed of the SubSeries listed below.
BRAFV600E remodels the melanocyte transcriptome and induces BANCR to regulate melanoma cell migration.
Specimen part, Cell line
View SamplesThe epidermal growth factor receptor (EGFR) is frequently overexpressed in cancer and is an important therapeutic target. Aberrant expression and function of microRNAs has been associated with tumorigenesis. Bioinformatic predictions suggest that the human EGFR mRNA 3-untranslated region contains three microRNA-7 (miR-7) target sites, which are not conserved across mammals. We found that miR-7 down-regulates EGFR mRNA and protein expression in cancer cell lines (lung, breast, and glioblastoma) via two of the three sites, inducing cell cycle arrest and cell death. Because miR-7 was shown to decrease EGFR mRNA expression, we used microarray analysis to identify additional mRNA targets of miR-7. These included Raf1 and multiple other genes involved in EGFR signaling and tumorigenesis. Furthermore, miR-7 attenuated activation of protein kinase B (Akt) and extracellular signal-regulated kinase 1/2 (ERK1/2), two critical effectors of EGFR signaling, in different cancer cell lines. These data establish an important role for miR-7 in controlling mRNA expression and indicate that miR-7 has the ability to coordinately regulate EGFR signaling in multiple human cancer cell types.
Regulation of epidermal growth factor receptor signaling in human cancer cells by microRNA-7.
No sample metadata fields
View Samples