Background. T cells in the thymus undergo opposing positive and negative selection processes so that the only T cells entering circulation are those bearing a T cell receptor (TCR) with a low affinity for self. The mechanism differentiating negative from positive selection is poorly understood, despite the fact that inherited defects in negative selection underlie organ-specific autoimmune disease in AIRE-deficient people and the non obese diabetic (NOD) mouse strain. Results. Here we use homogeneous populations of T cells undergoing either positive or negative selection in vivo together with genome-wide transcription profiling on microarrays to identify the gene expression differences underlying negative selection to an Aire-dependent organ-specific antigen, including the upregulation of a genomic cluster in the cytogenetic band 2F. Analysis of defective negative selection in the autoimmune-prone NOD strain demonstrates a global impairment in the induction of the negative selection response gene set, but little difference in positive selection response genes. Combining expression differences with genetic linkage data we identify differentially expressed candidate genes including Bim, Bnip3, Smox, Pdrg1, Id1, Pdcd1, Ly6c, Pdia3, Trim30 and Trim12. Conclusions. The data provide a molecular map of the negative selection response in vivo, and by analysis of deviations from this pathway in the autoimmune susceptible NOD strain, suggest that susceptibility arises from small expression differences in genes acting at multiple points in the pathway between the TCR and cell death.
Impairment of organ-specific T cell negative selection by diabetes susceptibility genes: genomic analysis by mRNA profiling.
No sample metadata fields
View SamplesIn a transgenic mouse model of Alzheimer disease (AD), cleavage of the amyloid precursor protein (APP) by the -secretase ADAM10 prevented amyloid plaque formation and alleviated cognitive deficits. Furthermore, there was a positive influence of ADAM10 over-expression on neurotransmitter-specific formation of synapses and on synaptic plasticity.
Differential gene expression in ADAM10 and mutant ADAM10 transgenic mice.
Sex, Age
View SamplesAdministration of spermidine, a natural polyamine whose intracellular concentration declines during human ageing, markedly extends the lifespan of various model organisms including yeast, flies and worms. In ageing yeast, spermidine treatment triggeres epigenetic deacetylation of histone H3 through inhibition of histone acetyltransferases (HAT), leading to induction of autophagy and thereby suppressing oxidative stress and necrosis. In order to further characterize the effects by spermidine supplementation of aging yeast cultures and to understand how global histone deacetylation affects gene transcription during aging, Affymetrix-based microarray analyses of three day old as well as ten day old cultures with and without administration of spermidine was performed.
Induction of autophagy by spermidine promotes longevity.
Age, Compound, Time
View SamplesRNA-sequencing was performed on human CD19- CD138+ bone marrow plasma cells. Overall design: 4 biological replicates of human CD19- CD138+ bone marrow plasma cells and 1 replicate each of naïve, IgM memory, IgG memory, and plasmablasts from peripheral blood.
Mitochondrial Pyruvate Import Promotes Long-Term Survival of Antibody-Secreting Plasma Cells.
Specimen part, Subject
View SamplesCryopreservation consists of preserving living cells or tissues at <-100C and has many applications in, for instance, stem cell and organ banking. Cryoprotectant agents, like ethylene glycol, are required for successful cryopreservation but have toxic side effects due to largely unknown mechanisms. In this work, we studied the toxicity of ethylene glycol in Human Umbilical Vein Endothelial Cells (HUVECs). Exposing cells to 60% ethylene glycol for two hours at 4C resulted in a slight decrease in cell growth, suggesting a modest toxicity of ethylene glycol and that HUVECs do not exhibit particular sensitivity to it. Gene expression analysis with whole genome micro-arrays revealed signatures indicative of a generalized stress response at 24 hours after stress and recovery at 72 hours, involving signaling pathways, glycoproteins, and genes involved in extracellular and transmembrane functions. These results reveal a new paradigm and signatures for future experiments in elucidating the toxicity effects of ethylene glycol in vascular endothelial cells.
Insights on cryoprotectant toxicity from gene expression profiling of endothelial cells exposed to ethylene glycol.
Specimen part, Treatment
View SamplesTotal RNA samples from three replicate cultures of wild type and mutant yeast strains was isolated and expression profile done using Affymetrix arrays. Comparsion between the samples indicate how mutation in a single amino acid residue in histone H4 (H4R45H) affects gene expression in yeast. Such a mutation in histone H4 is known to generate a specific class of mutants called SWI/SNF independent (SIN) mutants, and the mutants were identified by their ability to carry out transcription in the absence of yeast chromatin remodeling complex SWI/SNF. SIN mutations are known to affect higher order chromatin structure and the comparative expression profile would help identification of genes which get affected by such altered chromatin landscape.
A single amino acid change in histone H4 enhances UV survival and DNA repair in yeast.
No sample metadata fields
View SamplesThe expression profiles were determined using Affymetrix ATH1 arrays. Comparisons among the Col-0, ARF10 and mARF10 sample groups allow the identification of genes regulated by ARF10.
Repression of AUXIN RESPONSE FACTOR10 by microRNA160 is critical for seed germination and post-germination stages.
No sample metadata fields
View SamplesBackground:
Role of IFN-gamma and IL-6 in a protective immune response to Yersinia enterocolitica in mice.
Sex
View SamplesTo characterize the role of the ERI-6/7 helicase in endogenous small RNA pathways in C. elegans, small RNA populations from null alleles of eri-6 and eri-7, and from mutants of known endogenous RNAi pathway factors, eri-1 and ergo-1, were determined by deep sequencing, and compared to wild type. Overall design: Small RNA analysis in wild type and eri-1, ergo-1, eri-6 and eri-7 mutant C. elegans strains.
The ERI-6/7 helicase acts at the first stage of an siRNA amplification pathway that targets recent gene duplications.
Cell line, Subject
View SamplesArgonaute-associated siRNAs and Piwi-associated piRNAs have overlapping roles in silencing mobile genetic elements in animals. In C. elegans, mutator-class (mut) genes mediate siRNA-guided repression of transposons as well as exogenous RNA-directed gene silencing (RNAi), but their roles in endogenous RNA silencing pathways are not well understood. To characterize the endogenous small RNAs dependent on mutator-class genes, small RNA populations from a null allele of mut-16, as well as a regulatory mut-16(mg461) allele that disables only somatic RNAi, were subjected to deep sequencing. Overall design: Small RNA analysis in wild type and mut-16 mutant C. elegans strains
mut-16 and other mutator class genes modulate 22G and 26G siRNA pathways in Caenorhabditis elegans.
Cell line, Subject
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