-chloroprene (2-chloro-1,3-butadiene), a monomer used in the production of neoprene elastomers, is of regulatory interest due to the production of multi-organ tumors in mouse and rat cancer bioassays. A significant increase in female mouse lung tumors was observed at the lowest exposure concentration of 12.8 ppm while a small, but not statistically significant, increase was observed in female rats only at the highest exposure concentration of 80 ppm. The metabolism of chloroprene results in the generation of reactive epoxides and the rate of overall chloroprene metabolism is highly species dependent. To identify potential key events in the mode-of-action of chloroprene lung tumorigenesis, dose response and time course gene expression microarray measurements were made in the lungs of female mice and female rats. The gene expression changes were analyzed using both a traditional analysis of variance approach followed by pathway enrichment analysis and a pathway-based benchmark dose (BMD) analysis approach. Pathways related to glutathione biosynthesis and metabolism were the primary pathways consistent with cross-species differences in tumor incidence and transcriptional BMD values for the pathway were more similar to differences in tumor response than were estimated target tissue dose surrogates based on the total amount of chloroprene metabolized per unit mass of lung tissue per day. The closer correspondence of the transcriptional changes with the tumor response are likely due to their reflection of the overall balance between metabolic activation and detoxication reactions whereas the current tissue dose surrogate reflects only oxidative metabolism.
Cross-species transcriptomic analysis of mouse and rat lung exposed to chloroprene.
Sex, Age, Specimen part, Subject
View SamplesExposure to vanadium pentoxide (V2O5) is a cause of occupational bronchitis. We evaluated gene expression profiles in cultured human lung fibroblasts exposed to V2O5 in vitro in order to identify candidate genes that could play a role in airway remodeling associated with V2O5-induced bronchitis. Gene expression was measured at various time points over a 24 hr period using the Affymetrix Human Genome U133A 2.0 Array. Expression data were preprocessed using RMA with a log2 transformation. Statistical analysis was performed in R using the affylmGUI package using a linear model with contrasts between untreated control and V2O5-exposed fibroblasts. Genes identified as statistically significant were filtered by selecting only those genes that exhibited a > 2-fold change. Quantitative real-time RT-PCR was utilized to confirm expression of selected genes. More than 2000 genes were significantly changed in response to V2O5 over the time course of our experiment. Genes altered by V2O5 were involved in biologic processes related to cell growth and differentiation, oxidative stress responses, immune regulation, and interferon signaling and apoptosis. In particular, V2O5 induced genes that encode growth factors involved in epithelial repair (HB-EGF) or angiogenesis (VEGF), peroxide generating enzymes (SOD2), pro-inflammatory enzymes (PGHS2), while suppressing genes involved in growth arrest (GAS1, STAT-1) and cell cycle inhibition (CDKN1B). Our study also identified a variety of novel genes that could be used as biomarkers of V2O5-induced bronchitis or could serve as candidate genes for disease progression.
Genomic analysis of human lung fibroblasts exposed to vanadium pentoxide to identify candidate genes for occupational bronchitis.
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View SamplesProvided later
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Sex, Age, Disease, Disease stage
View SamplesAlthough HSF1 is known to play an important role in regulating the cellular response to proteotoxic stressors, little is known about the structure and function of the HSF1 signaling network under both stressed and unstressed conditions. In this study, we used a combination of chromatin immunoprecipitation (ChIP) microarray analysis and time course gene expression microarray analysis with and without siRNA-mediated inhibition of HSF1 comprehensively identify genes directly and indirectly regulated by HSF1 and examine the structure of the extended HSF1 signaling network. Correlation between promoter binding and gene expression was not significant for all genes bound by HSF1 suggesting that HSF1 binding per se is not sufficient for expression. However, the correlation with promoter binding was significant for genes identified as HSF1-regulated following siRNA knockdown allowing the identification of direct transcriptional targets of HSF1. Among promoters bound by HSF1 following heat shock, a gene ontology (GO) analysis showed significant enrichment only in categories related to protein folding. In contrast, analysis of the extended HSF1 signaling network showed enrichment in a variety of categories related to protein folding, anti-apoptosis, RNA splicing, ubiquitination and others, highlighting a complex transcriptional program directly and indirectly regulated by HSF1.
Genome-wide analysis of human HSF1 signaling reveals a transcriptional program linked to cellular adaptation and survival.
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View SamplesRotavirus infection is the single most important cause of severe diarrhea in young children worldwide. We used Affymetrix Human U95Av2 high density oligonucleotide arrays to compare gene expression profiles in peripheral blood mononuclear cells (PBMC) of 10 children with acute rotavirus diarrhea and 8 age-matched healthy children. We also examined patterns of gene expression in 5 convalescent-phase PBMC samples from rotavirus patients. For data analysis, we imported .cel files generated by Affymetrix MAS5.0 into Genetraffic 3.1 software (Iobion) and performed robust multi-chip analysis. We considered a gene in patients differentially expressed if its level of expression was at least 1.5-fold higher or lower than the baseline (arithmetic mean) of the corresponding gene in 8 controls and if its pattern of elevated or repressed expression was observed in at least 7 of the 10 patients. Using these criteria, we identified ~1% up- and ~2% down-regulated genes in acute-phase PBMC of patients. Up-regulated genes included those involved in the differentiation, maturation, activation, and survival of B cells, as well as an array of genes with function in inflammatory and antiviral activities. We observed a pattern of repressed expression of a number of genes involved in the various stages of T-cell development and activation. On the basis of these results, we conclude that rotavirus infection induces robust inflammatory response and B-cell activation but represses T-cell response.
Rotavirus infection alters peripheral T-cell homeostasis in children with acute diarrhea.
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View SamplesSevere asthma exacerbations in children requiring hospitalisation are typically associated with viral infection, and occur almost exclusively amongst atopics, but the significance of these comorbidities is unknown. We hypothesised that underlying interactions between immunoinflammatory pathways related to responses to aeroallergen and virus are involved, and that evidence of these interactions is detectable in circulating cells during exacerbations.
Interactions between innate antiviral and atopic immunoinflammatory pathways precipitate and sustain asthma exacerbations in children.
Specimen part, Disease, Disease stage
View SamplesBaseline glucocorticoid resistance profiles were measured in a panel of 15 paediatric T-Cell acute lymphoblastic leukaemia cell lines and correlated with Affymetrix Gene expression to identify genes and pathways associated with drug resistance in T-ALL. The cell lines' resistance to Methylprednisolone (MPRED) and Dexamethasone (DEX) was then tested using the MTT assay and IC50 values (drug concentration lethal to 50% of cells) for each drug were calculated.
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Disease, Disease stage, Cell line
View SamplesDendritic cells differentiate from their precursors in the airway mucosa under local environmental instruction. Airway epithelial cells (AEC) are a potent source of both pro- and anti-inflammatory mediators and are in intimate contact with intraepithelial DC and their precursors. Thus, AEC are likely candidates for influencing this differentiation process in order to tailor the DC for optimal function in the airway mucosa.
Airway epithelial cells regulate the functional phenotype of locally differentiating dendritic cells: implications for the pathogenesis of infectious and allergic airway disease.
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View SamplesHuman and mouse blood each contain two monocyte subsets. Here, we investigated the extent of their similarity using a microarray approach. Approximately 300 genes in human and 550 genes in mouse were differentially expressed between subsets. More than 130 of these gene expression differences were conserved between mouse and human monocyte subsets. We confirmed numerous differences at the cell surface protein level. Despite overall conservation, some molecules were conversely expressed between the two species subsets, including CD36, CD9, and TREM-1. Furthermore, other differences existed, including a prominent PPAR signature in mouse monocytes absent in human. Overall, human and mouse monocyte subsets are far more broadly conserved than currently recognized. Thus, studies in mice may indeed yield relevant information regarding the biology of human monocyte subsets. However, differences between the species deserve consideration in models of human disease studied in the mouse.
Comparison of gene expression profiles between human and mouse monocyte subsets.
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View SamplesTransforming growth factor (TGF)-1 is a multifunctional cytokine regulating a number of physiological and patho-physiological processes in the adult brain. Its expression is elevated during neurodegeneration, which is associated with reduced levels of neurogenesis. We have postulated that TGF-1 might be one of the crucial factors involved in limiting neurogenesis in the diseased brain.
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Age
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