Among the multiple mechanisms that control the intensity and duration of macrophage activation, the development of a state of refractoriness to a second stimulation in cells treated with LPS has long been recognized. Release of inhibitory cytokines and alterations in intracellular signaling pathways may be involved in the development of LPS tolerance. Although a number of molecules have been implicated, a detailed picture of the molecular changes in LPS tolerance is still missing. We have used a genome-wide gene expression analysis approach to (i) define which fraction of LPS target genes are subject to tolerance induction and (ii) identify genes that are expressed at high levels in tolerant macrophages. Our data show that in LPS tolerant macrophages the vast majority of LPS-induced gene expression is abrogated. The extent of tolerance induction varies for individual genes, and a small subset appears to be excepted. Compared to other negative control mechanisms of macrophages, e.g. IL-10-induced deactivation, LPS-tolerance inhibits a much wider range of transcriptional targets. Some previously described negative regulators of TLR-signaling (e.g. IRAK-M) were confirmed as expressed at higher levels in LPS-tolerant macrophages. In addition, we discuss other potential players in LPS tolerance identified in this group of genes.
A genome-wide analysis of LPS tolerance in macrophages.
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View SamplesMicroarrays were used to analyse gene expression underlying early tumourigenesis in Eker rats. Distinct classes of up- and downregulated genes were identified in different preneoplasic lesion vs. microdissected normal (healthy) renal tubules.
Molecular characterization of preneoplastic lesions provides insight on the development of renal tumors.
Sex, Specimen part
View SamplesThe mycotoxin deoxynivalenol (DON) is a secondary metabolite from Fusarium species and is frequently present on wheat and other cereals. The main effects of DON are a reduction of the feed intake and reduced weight gain of broilers. At the molecular level DON binds to the 60S ribosomal subunit and inhibits subsequently protein synthesis at the translational level. It has been suggested that cells and tissues with high protein turnover rate, like the liver and small intestine, are most affected by DON. However, little is known about other effects of DON e.g. at the transcriptional level. Therefore we decided to perform a microarray analysis, which allows us the investigation of thousands of transcripts in one experiment.
Fusarium mycotoxin-contaminated wheat containing deoxynivalenol alters the gene expression in the liver and the jejunum of broilers.
Age, Specimen part, Treatment
View SamplesThe Polycomb group (PcG) proteins form chromatin-modifying complexes that are essential for embryonic development and stem cell renewal and are commonly deregulated in cancer. Here, we identify their target genes using genome-wide location analysis in human embryonic fibroblasts. We find that Polycomb-Repressive Complex 1 (PRC1), PRC2, and tri-methylated histone H3K27 co-occupy >1000 silenced genes with a strong functional bias for embryonic development and cell fate decisions. We functionally identify 40 genes derepressed in human embryonic fibroblasts depleted of the PRC2 components (EZH2, EED, SUZ12) and the PRC1 component, BMI-1. Interestingly, several markers of osteogenesis, adipogenesis, and chrondrogenesis are among these genes, consistent with the mesenchymal origin of fibroblasts. Using a neuronal model of differentiation, we delineate two different mechanisms for regulating PcG target genes. For genes activated during differentiation, PcGs are displaced. However, for genes repressed during differentiation, we paradoxically find that they are already bound by the PcGs in nondifferentiated cells despite being actively transcribed. Our results are consistent with the hypothesis that PcGs are part of a preprogrammed memory system established during embryogenesis marking certain key genes for repressive signals during subsequent developmental and differentiation processes.
Genome-wide mapping of Polycomb target genes unravels their roles in cell fate transitions.
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View SamplesAdipose-derived stromal/stem cells (ASC) capable of multipotential differentiation can be isolated with high yield from human subcutaneous lipoaspirates. This study reports our recent experience isolating and immunophenotypically characterizing ASCs from >60 human subjects
Yield and characterization of subcutaneous human adipose-derived stem cells by flow cytometric and adipogenic mRNA analyzes.
No sample metadata fields
View SamplesAlthough mast cells elicit proinflammatory and type I IFN responses upon VSV infection, in response to L.monocytogenes (L.m) or S. Typhimurium (S.t), such cells elicit a transcriptional program devoid of type I IFN response.
Mast cells elicit proinflammatory but not type I interferon responses upon activation of TLRs by bacteria.
Specimen part
View SamplesChlamydia pneumoniae, an obligate intracellular bacterium, causes pneumonia in humans and mice. Toll-like receptors and the key adaptor molecule MyD88 play a critical role in inducing immunity against this microorganism and are crucial to survive the infection. To explore the influence of MyD88 on induction of immune responses in vivo on a genome wide level, WT or MyD88-/- mice were infected with C. pneumoniae upon anesthesia and the pulmonary transcriptome was analyzed three days later by microarrays. We find that the infection induced the transcription of 360 genes and repressed 18 genes in WT mice. Of these, 221 genes were not or weakly induced in lungs of MyD88-/- mice. This cluster contains primarily genes encoding for chemokines, cytokines and other immune effector molecules. Genes induced by interferons were abundant in a cluster of 102 genes which were only partially MyD88-dependent. Interestingly, a set of 37 genes were induced more strongly in MyD88-/- mice and most of them are involved in the regulation of cellular replication. In summary, ex vivo analysis of the pulmonary transcriptome upon infection with C. pneumoniae demonstrated a major impact of MyD88 on inflammatory responses but not on interferon-type responses, and identified MyD88-independent genes involved in cellular replication
MyD88-dependent changes in the pulmonary transcriptome after infection with Chlamydia pneumoniae.
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View SamplesThis experiment is an additional experiment to GSE6688. Mouse macrophages (ANA-1 cells) were infected in vitro with C. pneumoniae with a M.O.I. of 10. Twenty two genes were significantly upregulated. Examples of the most upregulated genes in mouse macrophages after C. pneumoniae infection are serum amyloid A3 (saa3), a protein that is mainly produced by activated macrophages during tissue injury or inflammation, MIP-2 (cxcl2) and irg1. Expression levels of all genes induced by C. pneumoniae in macrophages in vitro correlated with the results obtained from infected lungs from wild type mice (GSE6688), suggesting that this cell type participates in host defense in vivo against C. pneumoniae.
MyD88-dependent changes in the pulmonary transcriptome after infection with Chlamydia pneumoniae.
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View SamplesHyperglycemic memory is part of the pathogenesis of diabetic retinopathy. We established a novel mouse model of intermediate-term hyperglycemic memory and demonstrated that changes in gene expression and microvascular damage in the neurovascular unit of the diabetic retina persist after euglycemic reentry, indicating memory.
Hyperglycaemic memory affects the neurovascular unit of the retina in a diabetic mouse model.
Specimen part, Disease
View Samples3 weeks old aseptically grown WT and loss-of-function lines of SnRK1s (transgenic SnRK1a1 T-DNA insertion mutant line crossed with an estradiol inducible amiRNA construct targeting SnRK1a2) and group S1 bZIPs (bZIP1/bZIP53 T-DNA insertion mutant line crossed with an estradiol inducible amiRNA construct simultaneously targeting bZIP2, bZIP11 and bZIP44) were cultivated for 6h under extended night. Total RNA was extracted from whole seedlings and used for RNAseq library preparation. Overall design: Examination of global transcriptional changes in WT as well as SnRK1 and S1-bZIP knockdown lines in response to short-term dark cultivation.
Snf1-RELATED KINASE1-Controlled C/S<sub>1</sub>-bZIP Signaling Activates Alternative Mitochondrial Metabolic Pathways to Ensure Plant Survival in Extended Darkness.
Age, Subject
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